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Genetic expression profiles and chromosomal alterations in sporadic breast cancer in Mexican women
Abstract
Breast cancer is the second-leading cause of death among Mexican women >35 years of age. At the molecular level, changes in many genetic pathways have been reported to be associated with this neoplasm. To analyze these changes, we determined gene expression profiles and chromosomal structural alterations in tumors from Mexican women. We obtained mRNA to identify expression profiles with microarray technology, and DNA to determine amplifications and deletions, in 10 fresh sporadic breast tumor biopsies without treatment, as well as in 10 nonaffected breast tissues. Expression profiles were compared with genetic changes observed by comparative genomic hybridization (CGH). We compared the expression profiles against the structural alterations from the studied genes by means of microarrays; at least 17 of these genes correlated with DNA copy number alterations. We found that the following genes were overexpressed: LAMC1, PCTK3, CCNC, CCND1, FGF3, PCTK2, L1CAM, BGN, and PLXNB3 (alias PLEXR). Underexpressed genes included CASP9, FGR, TP73, HSPG2, and ERCC1; genes turned off included FRAP1, EPHA2 (previously ECK), IL12A, E2F5, TNFRSF10B, TNFRSF10A, EFNB3, and BCL2. The results will allow us, in the near future, to outline genes that could serve as diagnostic, prognostic, or target therapy markers for the Mexican population.
... In breast cancer, L1 copy number gain has been reported to correlate with increased L1 gene expression. 3 Similarly, CHL1 copy number deletion and decreased gene expression have been reported in breast cancer patients. 4,5 L1 expression is upregulated in a variety of tumor types including NSCLC, glioma, ovarian, pancreatic, gastric, and colon carcinomas; however, the presence of L1 CNVs in these cancers has not been investigated. ...
... However, copy number gain and increased expression of L1 have been demonstrated in breast cancer. 3 Moreover, increased L1 expression has been observed in various cancers including lung, glioma, ovarian, pancreatic, and colon carcinomas. [6][7][8][9][10][11] Our result showed that alterations in NFASC copy number were most common in adenocarcinoma. ...
Metastasis and cell adhesion are key aspects of cancer progression. Neurofascin (NFASC) is a member of the immunoglobulin superfamily of adhesion molecules and, while studies on NFASC are inadequate, other members have been indicated pivotal roles in cancer progression and metastasis. This study aimed at increasing the knowledge on the involvement of adhesion molecules in lung cancer progression by studying the regulation and role of NFASC in non-small cell lung cancer (NSCLC). Here, copy number variations in the NFASC gene were analyzed in tumor and non-tumorous lung tissues of 204 NSCLC patients. Frequent gene amplifications (OR = 4.50, 95% CI: 2.27-8.92, P ≤ 0.001) and increased expression of NFASC (P = 0.034) were identified in tumors of NSCLC patients. Furthermore, molecular mechanisms of NFASC in lung cancer progression were evaluated by investigating the effects of NFASC silencing on cell proliferation, viability, migration and invasion using siRNA technology in four NSCLC cell lines. Silencing of NFASC did not affect cell proliferation or viability but rather decreased NCSLC cell migration (P ≤ 0.001) and led to morphological changes, rearrangements in the actin cytoskeleton and changes in F-actin networks in migrating NSCLC cell lines. This study is the first to report frequent copy number gain and increased expression of NFASC in NCSLC. Moreover, these data suggest that NFASC is a novel regulator of NSCLC cell motility and support a role of NFASC in the regulation of NSCLC progression. This article is protected by copyright. All rights reserved.
... Molecular profiling has been a great aid in sorting out potential markers for early cancer diagnosis. From previously established databases of breast cancer clinical samples or in vitro cultured cell lines, the L1CAM gene or the region in the X chromosome where it is located (Xq28) [40,41] has been found to be abnormally amplified in some cases [33,42,43]. Its over-expression also is correlated with progressing stages of cancer in patients (Figure 1A, [33]). ...
... In order to invade through the ECM, gene expression changes causing proteolysis and degradation of the matrix are required [54,55], which evidently are not achieved by adding sL1 alone in a short time period. Given that L1CAM is rarely present other than in the nervous system, immune effector cells, and kidney under normal circumstances [23,41], its constitutive expression and shedding in tumors makes it an ideal marker for cancer detection and treatment. For example, short hairpin RNA targeting L1CAM, which has been found to impair axon outgrowth [56] in normal neurons, can disrupt cell proliferation and neurosphere formation of brain tumor cells [57] . ...
Neural recognition molecule L1CAM, which is a key protein involved in early nervous system development, is known to be abnormally expressed and shed in several types of cancers where it participates in metastasis and progression. The distinction of L1CAM presence in cancerous vs. normal tissues has suggested it to be a new target for cancer treatment. Our current study focused on the potential role of soluble L1CAM in breast cancer cell adhesion to extracellular matrix proteins, migration, and invasion.
We found L1 expression levels were correlated with breast cancer stage of progression in established data sets of clinical samples, and also were high in more metastatic breast cancer cell lines MDA-MB-231 and MDA-MB-435, but low in less migratory MDA-MB-468 cells. Proteolysis of L1 into its soluble form (sL1) was detected in cell culture medium from all three above cell lines, and can be induced by PMA activation. Over-expression of the L1 ectodomain in MDA-MB-468 cells by using a lentiviral vector greatly increased the amount of sL1 released by those cells. Concomitantly, cell adhesion to extracellular matrix and cell transmigration ability were significantly promoted, while cell invasion ability through Matrigel™ remained unaffected. On the other hand, attenuating L1 expression in MDA-MB-231 cells by using a shRNA lentiviral vector resulted in reduced cell-matrix adhesion and transmigration. Similar effects were also shown by monoclonal antibody blocking of the L1 extracellular region. Moreover, sL1 in conditioned cell culture medium induced a directional migration of MDA-MB-468 cells, which could be neutralized by antibody treatment.
Our data provides new evidence for the function of L1CAM and its soluble form in promoting cancer cell adhesion to ECM and cell migration. Thus, L1CAM is validated further to be a potential early diagnostic marker in breast cancer progression and a target for breast cancer therapy.
... An increase in L1-CAM expression could also be linked to breast cancer [58] . Upon analysis of gene expression patterns by DNA microarrays and chromosomal aberrations by comparative genomic hybridization (CGH) in human breast carcinoma samples and non-affected breast tissue, a correlation was detected between gene expression levels and chromosomal alterations. ...
... Upon analysis of gene expression patterns by DNA microarrays and chromosomal aberrations by comparative genomic hybridization (CGH) in human breast carcinoma samples and non-affected breast tissue, a correlation was detected between gene expression levels and chromosomal alterations. One of the nine overexpressed genes that correlated with chromosomal gains in breast cancer was L1-CAM [58] . Moreover, L1-CAM expression was downregulated in nonmetastatic breast cancer cells expressing the metastasis suppressor gene Nm23-H1. ...
L1-cell adhesion molecule (L1-CAM) is a cell adhesion receptor of the immunoglobulin superfamily, known for its roles in nerve cell function. While originally believed to be present only in brain cells, in recent years L1-CAM has been detected in other tissues, and in a variety of cancer cells, including some common types of human cancer.
We review the prevalence of L1-CAM in human cancer, the possible mechanisms involved in L1-CAM-mediated tumorigenesis, and cancer therapies based upon L1-CAM antibody treatment.
In colon cancer cells, the L1-CAM gene was identified as a target of the Wnt/beta-catenin-TCF signaling pathway, and L1-CAM was exclusively detected at the invasive front of colon and ovarian cancer tissue. The expression of L1-CAM in normal and cancer cells enhanced tumorigenesis and conferred metastasis in colon cancer cells. Antibodies against the L1-CAM ectodomain severely inhibited the proliferation of a variety of cancer cells in culture and reduced tumor burden when injected into mice harboring cancer cells expressing L1-CAM. These results, in addition to the presence of L1-CAM on the cell surface and its restricted distribution in normal tissues, make it an ideal target for tumor therapy.
... To be noted, regarding the genes used to construct the stemness subtype predictor and prognostic signature, GAS1 (Li et al., 2016a), CHIT1 (Li et al., 2016b), COL10A1 (Patra et al., 2021), FABP4 (Wang et al., 2019), HOXC9 (Hu et al., 2019), INHBB (Yuan et al., 2020), and NKAIN4 have been previously found to be associated with CRC development. In contrast, the role of PLXNB3 in CRC has not been yet investigated, although it was found to be overexpressed in breast cancer (Valladares et al., 2006). This evidence suggested that each stemness-related gene is crucial to CRC development and prognosis. ...
Cancer stem cells play crucial roles in colorectal cancer (CRC) tumorigenesis and treatment response. This study aimed to determine the value of the mRNA stemness index (mRNAsi) in CRC and introduce a stemness-related classification to predict the outcome of patients. mRNAsi scores and RNA sequence data of CRC patients were analyzed. We found that high mRNAsi scores were related to early-stage CRC and a better patient prognosis. Two stemness-based subtypes (subtype I and II) were identified. Patients in subtype I presented a significantly better prognosis than those in subtype II. Patients in these two subtype groups presented significantly different tumor immunity scores and immune cell infiltration patterns. Genomic variations revealed that patients in subtype I had a lower tumor mutation burden than those in subtype II. A three-gene stemness subtype predictor was established, showing good diagnostic value in discriminating patients in different subtypes. A prognostic signature based on five stemness-related genes was established and validated in two independent cohorts and clinical samples, showing a better predictive performance than other clinical parameters. We concluded that mRNAsi scores were associated with the clinical outcome in CRC patients. The stemness-related classification was a promising prognostic predictor for CRC patients.
... PPRP4 via NEDD4 downregulates ROBO1, which is implicated as a tumor suppressor in various cancers, resulting in activation of SRC and FAK, thus promoting breast cancer metastasis 29 . PLXNB3 is reportedly overexpressed in breast cancer tissues 30 , and CD74 is associated with poor breast cancer prognosis 31 . MIF can activate NF-kB through CD74 to control the dynamics and stability of mitochondria, thus promoting carcinogenesis by preventing apoptosis 32 . ...
Background: Immunotherapy plays an increasingly important role in the treatment of advanced female breast cancer, which has the highest mortality rate among malignant tumors. The purpose of this study was to identify immune-related genes associated with breast cancer prognosis as possible targets of immunotherapy, and their related biological processes and signaling pathways.
Methods: Clinical data and gene expression profiles of patients with breast cancer were extracted from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and divided into training (n = 1053) and verification (n = 508) groups. CIBERSORT was used to predict differences in immune cell infiltration in patient subsets stratified according to risk. Gene Ontology (GO) enrichment analysis was used to identify pathways associated with immune-related genes in patient subsets stratified according to risk.
Results: The prognostic model composed of 27 immune-related gene pairs significantly distinguished between high- and low-risk patients. Univariate and multivariate analyses indicated that the model was an independent prognostic factor for breast cancer. Among the identified genes, APOBEC3G, PLXNB1, and C3AR1 had not been previously studied in breast cancer and warrant further exploration. CCR chemokine receptor binding, regulation of leukocyte-mediated cytotoxicity, T cell migration, T cell receptor complex, and other pathways were significantly enriched in low-risk patients. M2 and M0 macrophages were more highly expressed in high-risk than in low-risk patients. CD8+ T cells and naïve B cells were more abundant in low-risk than in high-risk patients.
Conclusion: The immune-related gene pairs prognostic model developed in the current study can help assess breast cancer prognosis and provides a potential target and research direction for breast cancer immunotherapy in the future.
... It was shown earlier that Notch4 and CCNA1 participate in the development of drug resistance in breast [47] and ovarian [48] cancers. Moreover, upregulated expression of CCNA1 is associated with the increased rate of acute lymphoblastic leukemia development in the mouse model of this disease [49], whereas high levels of CCNB2 and CCNC expression may be observed in various growing tumors in colorectal adenocarcinoma, breast cancer [50], and pituitary adenoma [51]. On the contrary, downregulation of PTPN11 expression attenuates the influence of BRAF V600E on the expression of cyclin genes CCNA1, CCNB2, and CCNC and Notch4 gene, thereby pointing at the ambiguous role of SHP-2 in the development of tumors with the BRAF V600E mutation. ...
The MAPK (RAS/BRAF/MEK/ERK) signaling pathway is a kinase cascade involved in the regulation of cell proliferation, differentiation, and survival in response to external stimuli. The V600E mutation in the BRAF gene has been detected in various tumors, resulting in a 500-fold increase in BRAF kinase activity. However, monotherapy with selective BRAF V600E inhibitors often leads to reactivation of MAPK signaling cascade and emergence of drug resistance. Therefore, new targets are being developed for the inhibition of components of the aberrantly activated cascade. It was recently discovered that resistance to BRAF V600E inhibitors may be associated with the activity of the tyrosine phosphatase SHP-2 encoded by the PTPN11 gene. In this paper, we analyzed transcriptional effects of PTPN11 gene knockdown and selective suppression of BRAF V600E in a model of thyroid follicular epithelium. We found that the siRNA-mediated knockdown of PTPN11 after vemurafenib treatment prevented an increase in the expression CCNA1 and NOTCH4 genes involved in the formation of drug resistance of tumors. On the other hand, downregulation of PTPN11 expression blocked the transcriptional activation of genes (p21, pl5, pl6, RBI, and IGFBP7) involved in cell cycle regulation and oncogene-induced senescence in response to BRAF V600E expression. Therefore, it can be assumed that SHP-2 participates not only in emergence of drug resistance in cancer cells, but also in oncogene-induced cell senescence.
... EphrinA1 and EphA2 are co-expressed in many malignant tumor tissues and tumor-associated vascular endothelial cells. This overlapping expression pattern allows full contact between ephrinA1 and EphA2 (24). The EphA2 ligand ephrinA1 induces EphA2 phosphorylation and intracellular internalization and degradation, thus inhibiting tumor progression (25). ...
Background:
Research whether the Ad-ephrinA1-caspase-3-T has a targeted cytotoxic effect on breast cancer cells in vitro.
Methods:
First, the breast cancer cells were isolated, cultured and identified. The Ad-ephrinA1-caspase-3-T was used to infect human breast cells, and detect the effect that Ad-ephrinA1-caspase-3-T made on the viability of breast cancer cells with EphA2 positive by MTT. The effect of Ad-ephrinA1-caspase-3-T on the apoptosis of breast cancer cells was detected by flow cytometer. Finally, the specific cytotoxic effect of Ad-ephrinA1-caspase-3-T on target cells was examined by antibody neutralization experiments.
Results:
Breast cancer cells showed adherent growth, and high levels of EphA2 receptor and ephrinA1 expression were seen in breast cancer cells. Ad-ephrinA1-caspase-3-T showed a strong cytotoxic effect on breast cancer cells, and the growth inhibition rate was 42.3%. After culture for 72 h, the apoptosis rates corresponding to the dilution ratios of 1, 2, 4, 8 and 16 were 36%, 24%, 18%, 8%, and 7%, respectively, which were significantly higher than those of the control group, whose apoptosis rate was 3.5%. Neutralizing antibody could effectively reduce the cytotoxic effect of Ad-ephrinA1-caspase-3-T on EphA2 positive breast cancer cells.
Conclusions:
The Ad-ephrinA1-caspase-3-T has a targeted cytotoxic effect on breast cancer cells in vitro.
... The co-expression profile of MEG3 was identified with a large cluster of 3, 852 genes across 16 breast carcinomas (Fig. 7A) [34]. Heparan sulfate proteoglycan 2 (HSPG2) is a top correlated gene, which is underexpressed in breast cancer and inhibits chemotherapy resistance of breast cancer cells [35,36]. Data mining in bc-GenExMiner 4.0 confirmed a positive correlation between MEG3 and HSPG2 expression (Fig. 7B). ...
Background/aims:
Maternally expressed gene 3 (MEG3) is an imprinted gene with maternal expression, which may function as a tumor suppressor by inhibiting angiogenesis. To identify the prognostic value of MEG3 in breast cancer, systematic analysis was performed in this study.
Methods:
To evaluate gene alteration during breast carcinogenesis, we explored MEG3 expression using the Serial Analysis of Gene Expression Genie suite and Oncomine analysis. The prognostic roles of MEG3 in breast cancer were investigated using the PrognoScan database. The heat map and methylation status of MEG3 were determined using the UCSC Genome Browser.
Results:
We found that MEG3 was more frequently downregulated in breast cancer than in normal tissues and this correlated with prognosis. However, estrogen receptor and progesterone receptor status were found to be positively correlated with MEG3 expression. Conversely, basal-like status, triple-negative breast cancer status, and Scarff Bloom & Richardson grade criterion were negatively correlated with MEG3 expression. Following data mining in multiple big data databases, we confirmed a positive correlation between MEG3 and heparan sulfate proteoglycan 2 (HSPG2) expression in breast cancer tissues.
Conclusion:
MEG3 could be adopted as a marker to predict the prognosis of breast cancer with HSPG2. However, large-scale and comprehensive research is needed to clarify our results.
... While there is no mention of PCSK9 in the context of oncogenesis in the literature, overexpression of CDK18 has been seen in association with breast cancer and reduced expression of GOT1 has recently been demonstrated to be associated with poorer outcomes in glioblastoma. [14][15][16] Histopathologic analysis of contralateral quadrants from each cross-section revealed pleomorphic cells infiltrating through the pons. No microvascular proliferation or tumor necrosis was observed and the histology was consistent with a diffuse infiltrative glioma with focal anaplastic changes. ...
Improved molecular understanding is needed for rational treatment of diffuse intrinsic pontine gliomas (DIPG). Here, using multi-focal paired tumor and germline exome DNA and RNA sequencing, we uncovered phosphatase and tensin homolog (PTEN) loss as a clonal mutation in the case of a 6-year-old boy with a diffuse intrinsic pontine glioma, and incorporated copy number alteration analyses to provide a more detailed understanding of clonal evolution in diffuse intrinsic pontine gliomas. As well, using the PedcBioPortal, we found alterations in PTEN in 16 of 326 (4.9%) cases of pediatric high-grade glioma (3 of 154 (1.9%) brainstem) for which full sequencing data was available. Our data strengthens the association with PTEN loss in diffuse intrinsic pontine gliomas and provides further argument for the inclusion of PTEN in future targeted sequencing panels for pediatric diffuse intrinsic pontine gliomas and for the development and optimization of mTOR/PI3K inhibitors with optimal central nervous system penetration.
... Analysis of gene expression data from the European Molecular Biology Laboratories -European Bioinformatics Institute (EMBL-EBI) database 31,32 revealed that 143 out of 160 genes that encode putative nucleases are upregulated in BCa cell lines compared with whole blood, including cell lines that lack EpCAM expression ( Figure 2A; Table S1). The expression of nucleases that have been implicated in cancer progression (EXO1, NEIL3, FEN1, DNA2, and ERCC1) 23,24,[33][34][35][36][37] was also higher in cancer cells versus blood. In addition, nuclease gene expression is elevated in the clear majority of BCa cell lines ( Figure 2B, left panel) and in analyzed patient tumor samples ( Figure 2B, right panel). ...
... Analysis of gene expression data from the European Molecular Biology Laboratories -European Bioinformatics Institute (EMBL-EBI) database 31,32 revealed that 143 out of 160 genes that encode putative nucleases are upregulated in BCa cell lines compared with whole blood, including cell lines that lack EpCAM expression ( Figure 2A; Table S1). The expression of nucleases that have been implicated in cancer progression (EXO1, NEIL3, FEN1, DNA2, and ERCC1) 23,24,[33][34][35][36][37] was also higher in cancer cells versus blood. In addition, nuclease gene expression is elevated in the clear majority of BCa cell lines ( Figure 2B, left panel) and in analyzed patient tumor samples ( Figure 2B, right panel). ...
A challenge for circulating tumor cell (CTC)-based diagnostics is the development of simple and inexpensive methods that reliably detect the diverse cells that make up CTCs. CTC-derived nucleases are one category of proteins that could be exploited to meet this challenge. Advantages of nucleases as CTC biomarkers include: (1) their elevated expression in many cancer cells, including cells implicated in metastasis that have undergone epithelial-to-mesenchymal transition; and (2) their enzymatic activity, which can be exploited for signal amplification in detection methods. Here, we describe a diagnostic assay based on quenched fluorescent nucleic acid probes that detect breast cancer CTCs via their nuclease activity. This assay exhibited robust performance in distinguishing breast cancer patients from healthy controls, and it is rapid, inexpensive, and easy to implement in most clinical labs. Given its broad applicability, this technology has the potential to have a substantive impact on the diagnosis and treatment of many cancers.
... HSPG2 and type 4 collagens are well known constituents of the basement membrane in normal mammary epithelium and loss of expression is commonly observed during breast cancer pathogenesis. [191][192][193] Interestingly, a 26-kDa region of COL4A1, termed arresten, has been shown to possess tumor suppressor and antiangiogenic properties in murine models of tumor metastasis. [194][195][196] Further, a 24-kDa region of COL4A2, termed canstantin, has also been similarly shown to inhibit tumor growth and discourage angiogenesis in xenograft models of tumorigenesis and in in vitro analyses of endothelial cells, respectively. ...
The utilization of high-throughput -omics strategies, such as proteomics, in the analysis of breastcancer will function to define central molecular characteristics across a disease that is associatedwith a high degree of molecular heterogeneity. Data reported herein details the investigation ofkey subjects in breast cancer biology focused on the characterization of endogenous andexperimentally-induced disease biology characteristics utilizing the application of LC-MS basedproteomic analyses of both in vitro models of breast cancer as well as primary clinical samples.Results include a combined global and functional proteomic strategy to identify governingfunctional roles for mutually, differentially abundant proteins observed across three divergentcell line models of breast cancer. Further, evidence is presented which provides insights into theregulatory activity of the breast cancer-associated microRNA (miR-145) in several cell linemodels of breast cancer in which expression of this microRNA has been restored. Lastly, robustanalyses are detailed focused on the identification of differential protein characteristics indicativeof disease stage as well as of recurrent disease in breast cancer derived from proteomic analysisof formalin-fixed, paraffin embedded (FFPE) clinical samples. These studies contribute to thefield of proteomics in the form of 1) providing robust experimental workflows directed towardsinvestigation of functional themes and associated functional targets in large protein data sets 2)detailing strategies for navigating the application of proteomic analysis to microRNA targetdiscovery and 3) further development and utilization of methodologies towards the proteomicanalysis of clinical, FFPE tissue samples. Furthermore, these studies benefit the breast cancercommunity on several fronts including 1) the elucidation of provocative protein candidateswhich warrant further investigation for their role in regulating disease mechanisms underlyingvbreast cancer biology and 2) through the discovery of diagnostic markers indicative of discretesubtypes and stages of disease progression in breast cancer. The results reported herein detaildisease-specific protein abundance characteristics associated with neoplastic progression inbreast cancer that will benefit further expansion of the basic biological understanding of thisdisease and describes novel proteins for further evaluation as biomarker candidates for thediagnosis of breast cancer.
... Second, we analysed the DEGs among TP53-associated DE-MMPVs. Adan Valladares showed that CCND1 and LAMC1 are overexpressed in breast cancer patients [35]. We observed that, compared to patients with mutated TP53, the expression of CCND1 and LAMC1 is increased in patients with wild type TP53. ...
MicroRNAs (miRNAs) are a class of small noncoding RNAs that can regulate gene expression by binding to target mRNAs and induce translation repression or RNA degradation.
There have been many studies indicating that both miRNAs and mRNAs display aberrant expression in breast cancer.
Previously, most researches into the molecular mechanism of breast cancer examined miRNA expression patterns and mRNA expression patterns separately.
In this study, we systematically analysed miRNA-mRNA paired variations (MMPVs),
which are miRNA-mRNA pairs whose pattern of regulation can vary in association with biopathological features, such as the oestrogen receptor (ER),
TP53 and human epidermal growth factor receptor 2 (HER2) genes, survival time, and breast cancer subtypes.
We demonstrated that the existence of MMPVs is general and widespread but that there is a general unbalance in the distribution of MMPVs among the different biopathological features.
Furthermore, based on studying MMPVs that are related to multiple biopathological features, we propose a potential crosstalk mechanism between ER and HER2.
... [23,3233343536. Therefore the GSTM1 and GSTT1 null alleles have also been reported to be associated with diminished GST enzyme activity altering response and toxicity from chemotherapy in patients with acute leukemia, breast cancer and metastatic colorectal cancer [15,20,31,37]. The chemotherapy exerts the antineoplastic effect by generating reactive oxygen products (ROS) and by products that are metabolized by different enzymes like GSTT1 and GSTM1 [38]. ...
Introduction: Breast cancer is a common disease diagnosed in Mexican women and the first leading cause of death [1]. Heterogeneity in patients' response to treatment is consistently observed across populations. Glutathione S-transferases (GSTs) are involved in the metabolism of environmental carcinogens, reactive oxygen species and chemotherapeutic agents by catalyzing the glutathione with electrophilic compounds. The deletion of GSTT1 and GSTM1 genes result in loss of enzyme activity. A few studies evaluated the response to treatment and the polymorphisms of GSTT1 and GSTM1. The aim of this work is to make the association of the null polymorphisms of GSTT1 and GSTM1 with the response to chemotherapy basically doxorubicin and cyclophosphamide. Methods: The genotyping of thirty patients with breast cancer was made with the Polymerase chain reaction, to identify the polymorphisms of GSTT1 and GSTM1. We deter-mine the status of HER-2 neu, estrogen and progesterone receptors, then the response to treatment was made with an ultrasound and pathological data. We made the association with the χi 2 statistics using a p ≤ 0.05. Results: Using the Sigma Stat 3.5 program and the chi-squared analysis, we do not observe a significant association with the GSTT1+/GSTM1+, GSTT1–/GSTM1+ and GSTT1–/GSTM1– polymorphisms and the better or worse response to cyclo-phosphamide and doxorubicin. With the HER-2 neu, estrogen and progesterone receptors status, we neither found an association with the response to the therapy. Conclusion: This study suggests that GSTT1 and GSTM1 polymorphisms have no statistical significance between the genotype of women with advanced breast cancer and the response to neoadjuvant chemotherapy, but we can see a clear tendency toward better response with the null genotype.
... Among the mRNAs potentially targeted by miR-205, identified using the miRGen database (Megraw et al., 2007), we selected a component of the extracellular matrix named LAMC1. This protein has been implicated in a wide variety of biological processes including cell adhesion, differentiation, proliferation, migration, signaling, neurite outgrowth and metastasis, and it is altered in human hepatocellular carcinoma (Lietard et al., 1997), breast cancer (Valladares et al., 2006) and glioblastoma, where it is targeted by miR-124a (Fowler et al., 2011). ...
An increasing body of evidence highlights an intriguing interaction between microRNAs and transcriptional factors involved in determining cell fate, including the well known “genome guardian” p53. Here we show that miR‐205, oncosuppressive microRNA lost in breast cancer, is directly transactivated by oncosuppressor p53.
Moreover, evaluating miR‐205 expression in a panel of cell lines belonging to the highly aggressive triple negative breast cancer (TNBC) subtype, which still lacks an effective targeted therapy and characterized by an extremely undifferentiated and mesenchymal phenotype, we demonstrated that this microRNA is critically down‐expressed compared to a normal‐like cell line. Re‐expression of miR‐205 where absent strongly reduces cell proliferation, cell cycle progression and clonogenic potential in vitro, and inhibits tumor growth in vivo, and this tumor suppressor activity is at least partially exerted through targeting of E2F1, master regulator of cell cycle progression, and LAMC1, component of extracellular matrix involved in cell adhesion, proliferation and migration.
... TP73, a structural and functional homologue of transcription factor P53, has the potential to activate TP53 target genes and to interact with P53, as well as inhibit cell growth in a P53-like manner by inducing apoptosis when overproduced. Under-expression or loss may contribute to arrest failure at cell-cycle check points [35]. Homeotic genes encode master regulatory transactivating proteins which are likely to regulate other genes within the mammary epithelium [36]. ...
This study aimed to determine the changes in the expression of genes for selected specific transcriptional factors that have both activating and repressing functions in in vitro ductal breast cancer cells, under the influence of paclitaxel, applying the microarray technique. The cells are treated with 60 ng/ml and 300 ng/ml doses of paclitaxel that correspond to those applied in breast cancer therapy. About 60 ng/ml doses of paclitaxel cause a statistically significant increase in expression of all the 16 analysed genes coding transcriptional factors, ranging from 1.84-fold (for PO4F2) to 4.65-fold (for LMO4) (p < 0.05) in comparison with the control cells, and enhanced the taxane mechanism of action. The 300 ng/ml doses of paclitaxel cause a cytotoxic effect in the cells. In this article, we argue that these changes in gene expression values may constitute prognostic and predictive factors in ductal breast cancer therapy.
... A human genome-wide linkage analysis of posterior amorphous corneal dystrophy identified a region of human chromosome 12 that is orthologous to a Mcs6 region that contains genes DCN, LUM, KERA, and EPYC [21]. PCTK2 has been shown to be upregulated in sporadic breast cancer biopsies in women of Mexican ancestry [22]. Suppressor of cytokine signaling 2 (Socs2) is also a promising potential candidate gene in Mcs6. ...
Only a portion of the estimated heritability of breast cancer susceptibility has been explained by individual loci. Comparative genetic approaches that first use an experimental organism to map susceptibility QTLs are unbiased methods to identify human orthologs to target in human population-based genetic association studies. Here, overlapping rat mammary carcinoma susceptibility (Mcs) predicted QTLs, Mcs6 and Mcs2, were physically confirmed and mapped to identify the human orthologous region. To physically confirm Mcs6 and Mcs2, congenic lines were established using the Wistar-Furth (WF) rat strain, which is susceptible to developing mammary carcinomas, as the recipient (genetic background) and either Wistar-Kyoto (WKy, Mcs6) or Copenhagen (COP, Mcs2), which are resistant, as donor strains. By comparing Mcs phenotypes of WF.WKy congenic lines with distinct segments of WKy chromosome 7 we physically confirmed and mapped Mcs6 to ~33 Mb between markers D7Rat171 and gUwm64-3. The predicted Mcs2 QTL was also physically confirmed using segments of COP chromosome 7 introgressed into a susceptible WF background. The Mcs6 and Mcs2 overlapping genomic regions contain multiple annotated genes, but none have a clear or well established link to breast cancer susceptibility. Igf1 and Socs2 are two of multiple potential candidate genes in Mcs6. The human genomic region orthologous to rat Mcs6 is on chromosome 12 from base positions 71,270,266 to 105,502,699. This region has not shown a genome-wide significant association to breast cancer risk in pun studies of breast cancer susceptibility.
... This complex mediates the proliferation inhibiting effect of transforming growth factor-beta. A downregulation of E2F5 was already reported in breast cancer [43]. ...
Lysyl oxidase-like 2 (LOXL2) plays a part in epithelial-mesenchymal transition (EMT) by stabilizing the transcription factor SNAI1. Previous studies showed that LOXL2 is one of the most highly and specifically upregulated genes in pancreatic cancer. LOXL2 was also found to be strongly upregulated in the secretome of established pancreatic cancer cell lines. To get more insight into the aggressive growth and infiltrating nature of pancreatic cancer, we evaluated the functional role of LOXL2 in pancreatic cancer cells.
Gene inhibition by small interfering RNAs was used to silence LOXL2 in pancreatic cancer cell lines MiaPaCa-2 and Panc1. Cell death, proliferation, and morphology of transfected cells were determined. Cell characteristics under cell stress and gemcitabine treatment were analyzed. Gene expression analysis of transfected cells by DNA microarray was used to understand the processes of chemosensitization.
Silencing of LOXL2 in pancreatic cancer cells resulted in an augmented sensitivity toward gemcitabine treatment, with significantly elevated cell death and reduced viable cells. However, transfection had no direct effect on morphology or growth pattern of Mia PaCa-2 and Panc1 cell lines. Gene expression analysis identified among others the transcription factor E2F5 as possible target of LOXL2.
Gene inhibition of the EMT regulatory gene LOXL2 resulted in a distinct sensitization toward gemcitabine. Additionally, gene expression analysis showed a role for LOXL2 in the regulation of different transcription factors associated with invasion and metastasis. Our results suggest that the improved response toward chemotherapy in LOLX2-silenced pancreatic cancer cells is possibly mediated by the transcription factor E2F5.
... BGN is associated with transforming growth factor beta activation of p38 mitogen-activated protein kinase and plays a role in cellular adhesion and migration in human osteosarcoma [80]. BGN was markedly overexpressed in breast carcinoma [81] and in salivary gland carcinomas [82]. Another factor that was previously linked to invasiveness and metastasis in a variety of malignancies is the family of metalloproteinases [83,84]. ...
The new classification of malignant fibrous histiocytoma leaves only a small group of tumors without further line of differentiation, so-called pleomorphic sarcomas, not otherwise specified (NOS) as a pseudo-entity. This study focused on these tumors and analyzed the association of gene expression profiles to clinical outcome.
Ten fresh samples of pleomorphic NOS sarcomas were evaluated histopathologically and by means of microarray analysis. Analysis of expression profiles was performed by clustering methods as well as by statistical analysis of primary vs recurrent tumors, irradiated vs nonirradiated tumors, tumors of patients above and below 60 years of age, male and female, and of tumors that developed metastatic or recurrent disease during the clinical course and those that did not.
Tumor clustering did not correlate to any histopathological or clinical finding. Detailed gene expression analysis showed a variety of genes whose upregulation (platelet-derived growth factor receptor alpha polypeptide, solute carrier family 39 member 14, solute carrier family 2 member 3, pleiotrophin, trophinin, pleckstrin and Sec7 domain containing 3, enolase 2, biglycan, SH3 and cysteine-rich domain, matrix metalloproteinases 16) and whose downregulation (tissue inhibitor of metalloproteinase 4, hairy/enhancer of split related with YRPW motif 2, protein tyrosine phosphatase receptor-type Z polypeptide 1, SH3 domain GRB2-like 2, microtubule-associated protein 7, potassium voltage-gated channel shaker-related subfamily member 1, RUN and FYVE domain containing 3, Sin3A-associated protein 18 kDa, proline-rich 4, calcium/calmodulin-dependent protein kinase ID, myeloid/lymphoid or mixed-lineage leukemia translocated to 3, insulin-like growth factor binding protein 5, nucleoside diphosphate-linked moiety X-type motif 9, NudC domain containing 3, imprinted in Prader-Willi syndrome, TAF6-like RNA polymerase II p300/CBP-associated factor 65 kDa, WD repeat and SOCS box-containing 2, adenosine diphosphate ribosylation factor 3, KRR1, proliferation-associated 2G4; CD36, complement component (3b/4b) receptor 1, solute carrier family 4 sodium bicarbonate cotransporter member 4, lipoprotein lipase (LPL), GATA binding protein 3, LPL, glutathione peroxidase 3, D: -aspartate oxidase, apolipoprotein E, sphingomyelin phosphodiesterase acid-like 3A) were associated with poor clinical outcome in terms of development of metastatic or recurrent disease.
The classification of these tumors may undergo further changes in the future. Gene expression profiling can provide additional information to categorize pleomorphic sarcoma (NOS) and reveal potential prognostic factors in this "entity."
... Blasting this peptide sequence against NCBI-nr database showed that part of the peptide 'ELAEQMT' aligned perfectly with mouse PCTAIRE-motif protein kinase 2 (pctk2). Valladares et al (36) showed over-expression of pctk2 in breast cancer samples from Mexican women. The PCTAIRE protein kinases comprise a distinct subfamily of the cell division controller 2 (cdc2) related serine/threonine-specific protein kinases. ...
To assess the potential of tumor-associated, alternatively spliced gene products as a source of biomarkers in biological fluids, we have analyzed a large data set of mass spectra derived from the plasma proteome of a mouse model of human pancreatic ductal adenocarcinoma. MS/MS spectra were interrogated for novel splice isoforms using a nonredundant database containing an exhaustive three-frame translation of Ensembl transcripts and gene models from ECgene. This integrated analysis identified 420 distinct splice isoforms, of which 92 did not match any previously annotated mouse protein sequence. We chose seven of those novel variants for validation by reverse transcription-PCR. The results were concordant with the proteomic analysis. All seven novel peptides were successfully amplified in pancreas specimens from both wild-type and mutant mice. Isotopic labeling of cysteine-containing peptides from tumor-bearing mice and wild-type controls enabled relative quantification of the proteins. Differential expression between tumor-bearing and control mice was notable for peptides from novel variants of muscle pyruvate kinase, malate dehydrogenase 1, glyceraldehyde-3-phosphate dehydrogenase, proteoglycan 4, minichromosome maintenance, complex component 9, high mobility group box 2, and hepatocyte growth factor activator. Our results show that, in a mouse model for human pancreatic cancer, novel and differentially expressed alternative splice isoforms are detectable in plasma and may be a source of candidate biomarkers.
... Genomic analysis of cancer in Mexico is experiencing a transition from the classical genetic approaches to the generation and management of genome-wide analysis using highthroughput genomic technologies. Genomic methods, including genome-wide expression and DNA copy number variation analysis (Hidalgo et al. 2005;Valladares et al. 2006;Vazquez-Ortiz et al. 2007), as well as serial analysis of gene expression (PerezPlasencia et al. 2005), have powered the study of cervical and breast cancers, and the application of genomic analysis of other cancers is becoming more common. To develop human genetics and genomic medicine in Mexico, the country will require more robust study designs based on the known genetic structure of the Mexican population and the collection of large number of samples in different diseases. ...
Mexico faces important demographic and epidemiological transitions with significant implications to patterns of disease, disability, and death. On the one hand, there are problems of underdevelopment and, on the other, the emerging challenges of the chronic and degenerative diseases of the industrialized world. For these diseases, prevention becomes a key strategy for alleviating a major burden to the economy and health of the Mexican population. Genomic medicine has become a priority to the Mexican government as a means of finding new strategies to tackle common diseases. In 2000, strategic planning for genomic medicine began, from a feasibility study and a multi-institutional consortium effort, to the creation of a National Institute of Genomic Medicine by the Mexican congress in 2004. Current research programs in genomic medicine in Mexico include the construction of a haplotype map of the Mexican population, several genome-wide association studies for common diseases, such as diabetes, obesity, cardiovascular disease, and cancer, as well as translational medicine projects that include biomarkers discovery for several kinds of cancer, pharmacogenomics, and nutrigenomics. Although this strategy has been successful, there are challenges that still need to be addressed, including increased investment in science and technology to stimulate a more vigorous and competitive research environment, development of more effective basic and clinical research synergies, recruitment and training of more human resources in genomic medicine, developing mechanisms to stimulate translational research, and developing a more modern regulatory framework to ensure that genomic medicine will successfully contribute to improve healthcare in the Mexican population.
Numerous studies have demonstrated an inverse link between cancer and Alzheimer’s disease (AD), with data suggesting that people with Alzheimer’s have a decreased risk of cancer and vice versa. Although other studies have investigated mechanisms to explain this relationship, the connection between these two diseases remains largely unexplained. Processes seen in cancer, such as decreased apoptosis and increased cell proliferation, seem to be reversed in AD. Given the need for effective therapeutic strategies for AD, comparisons with cancer could yield valuable insights into the disease process and perhaps result in new treatments. Here, through a review of existing literature, we compared the expressions of genes involved in cell proliferation and apoptosis to establish a genetic basis for the reciprocal association between AD and cancer. We discuss an array of genes involved in the aforementioned processes, their relevance to both diseases, and how changes in those genes produce varying effects in either disease.
Cyclin-dependent kinases (CDKs) are serine/threonine kinases whose catalytic activities are regulated by interactions with cyclins and CDK inhibitors (CKIs). CDKs are key regulatory enzymes involved in cell proliferation through regulating cell-cycle checkpoints and transcriptional events in response to extracellular and intracellular signals. Not surprisingly, the dysregulation of CDKs is a hallmark of cancers, and inhibition of specific members is considered an attractive target in cancer therapy. In breast cancer (BC), dual CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, combined with other agents, were approved by the Food and Drug Administration (FDA) recently for the treatment of hormone receptor positive (HR+) advanced or metastatic breast cancer (A/MBC), as well as other sub-types of breast cancer. Furthermore, ongoing studies identified more selective CDK inhibitors as promising clinical targets. In this review, we focus on the roles of CDKs in driving cell-cycle progression, cell-cycle checkpoints, and transcriptional regulation, a highlight of dysregulated CDK activation in BC. We also discuss the most relevant CDK inhibitors currently in clinical BC trials, with special emphasis on CDK4/6 inhibitors used for the treatment of estrogen receptor-positive (ER+)/human epidermal growth factor 2-negative (HER2−) M/ABC patients, as well as more emerging precise therapeutic strategies, such as combination therapies and microRNA (miRNA) therapy.
Exploring the genetic aberrations favoring metastasis is important for understanding and developing novel strategies to combat cancer metastasis. It remains lack of effective treatment for the dismal prognosis of intrahepatic cholangiocarcinoma (ICC). Here, we aimed to study genetic alternations during lymph node metastasis of ICC and investigate potential mechanisms and clinical strategy focused on mutations. We performed whole‐exome sequencing and transcriptome sequencing on samples from 30 ICC patients, including lymph node metastases from five of the patients. We identified the alterations of genetic pattern related to lymph node metastases of ICC. EPHA2, a member of the tyrosine kinase family, was found to be frequently mutated in ICC. Correlation analysis indicated that EPHA2 mutations were closely associated with lymph node metastasis of ICC. In vitro and in vivo experiments revealed that EPHA2 mutations could lead to ligand independent phosphorylation of Ser897, and promote lymphatic metastasis of ICC, in which NOTCH1 signaling pathway played an important role. In both in vitro assays and patient‐derived xenografts, an inhibitor of Ser897 phosphorylation effectively suppressed the metastasis of ICC with mutated EPHA2. Our findings demonstrated that EPHA2 mutants may be an attractive therapeutic target for lymphatic metastasis of ICC.
OBJECTIVE: To study the protein expressions of EphA2 and EphrinA1 in breast cancer tissues and to explore their significance. METHODS: Using immunohistochemistry Sp method to detect the protein expressions of EphA2 and EphrinA1 in cancer tissues from 130 breast cancer patients. Then studying their relationship to clinicopathological factors. RESULTS: Among the 130 breast carcinoma cases, The total positive rate of EphA2 and EphrinA1 protein was 72. 31% and 59. 23%. The positive expression of EphA2 protein were associated with clinical stage, lymph node metastasis and histological grade(P<0. 05). The positive expression of EphrinAl protein were significantly correlated with clinical stage and histological grade(P<0. 05). The positive staining of EphA2 and EphrinAl protein co-located in roughly the same tumor areas and vascular endothelial cells. Their distribution were fundamentally unanimous and their expression were positively correlated (P<0. 05). CONCLUSIONS: EphA2 and EphrinA1 may be involved in carcinogenesis and development procedures of breast carcinoma. The combined detection of EphA2 and EphrinA1 can help to predict the clinical and pathologic characteristics of breast carcinoma. It is an important index to guide treatment, and they are predictive factors for breast cancer.
Objective: To investigate the expressions of ER, PR and EphA2 in breast cancers and their clinical significance. Methods: The expressions of ER, PR and EphA2 were detected in 130 cases of breast career by immunohistochemistry S-P method. Results: (1) The positive rates of expressions of ER, PR and EphA2 were 63.1%, 58.4% and 72.3%, respectively. (2) No significant association of expression of ER and PR was noted with age, histological types, tumor size, lymphatic metatasis and clinical stages. (3) The expression of EphA2 was related to clinical stages and lymphatic metatasis(P < 0.05), but not to age, tumor size and histological types(P > 0.05). (4) The positive rate of expression of EphA2 in the group with the positive expression of ER and PR was lower than that in the group with negative expression of ER and PR(P < 0.05). Conclusions: ER, PR and EphA2 are related with the occurrence and development of breast cancer. The combined detection of ER, PR and EphA2 can help to predict the clinical and pathologic characteristics of breast career, which is an important index to guide treatment. ER, PR and EphA2 are predictive factors for breast cancer.
L1-type proteins are transmembrane cell adhesion molecules with an evolutionary well-conserved protein domain structure of usually six immunoglobulin and five fibronectin type III domains. By engaging in many different protein-protein interactions they are involved in a multitude of molecular functions and are important players during the formation and maintenance of metazoan nervous systems. As a result, mutations in L1-type genes cause a great variety of phenotypes, most of which are neurological in nature. In humans, mutations in the L1CAM gene are responsible for L1 syndrome and other L1-type genes have been implicated in conditions as varied as mental retardation, autism, schizophrenia, multiple sclerosis, and other disorders. Equally, the overexpression of L1-type proteins appears to have deleterious effects in various types of human tumor cells, where they generally contribute to an increase in cell mobility and metastatic potential.
Objectives
To determine the distribution of the distinct breast carcinoma phenotypes in Venezuelan patients, characterize the clinicopathologic variables in each subgroup, and establish survival patterns for each phenotype.
Patients and methods
We retrospectively evaluated data from 266 patients diagnosed with breast carcinoma and an immunohistochemical study of the initial biopsy. The patients were classified into 3 groups of tumor phenotypes (estrogen receptor-positive, HER2/neu overexpression and triple-negative). We determined and correlated epidemiological, clinical and pathological variables.
Results
The tumor phenotype groups were distributed as follows: estrogen receptor-positive in 60.9%, triple-negative in 27.8%, and HER2/neu overexpression in 11.3%. A total of 92% of the patients with triple-negative phenotype were African American. Survival was best with the estrogen receptor-positive phenotype and worst with the triple-negative phenotype, but these differences were not significant.
Conclusions
The phenotypic distribution of breast carcinoma in Venezuela is similar to that reported in the general literature. The incidence of the triple-negative subtype, which showed the worst survival –although this result was not significant– was higher than in other populations. Most patients in this subgroup were African American.
Although two major breast cancer susceptibility genes, BRCA1 and BRCA2, have been identified accounting for 20% of breast cancer genetic risk, identification of other susceptibility genes accounting for 80% risk remains a challenge due to the complex, multi-factorial nature of breast cancer. Complexity derives from multiple genetic determinants, permutations of gene-environment interactions, along with presumptive low-penetrance of breast cancer predisposing genes, and genetic heterogeneity of human populations. As with other complex diseases, dissection of genetic determinants in animal models provides key insight since genetic heterogeneity and environmental factors can be experimentally controlled, thus facilitating the detection of quantitative trait loci (QTL). We therefore, performed the first genome-wide scan for loci contributing to radiation-induced mammary tumorigenesis in female F2-(Dahl S x R)-intercross rats. Tumorigenesis was measured as tumor burden index (TBI) after induction of rat mammary tumors at forty days of age via (127)Cs-radiation. We observed a spectrum of tumor latency, size-progression, and pathology from poorly differentiated ductal adenocarcinoma to fibroadenoma, indicating major effects of gene-environment interactions. We identified two mammary tumorigenesis susceptibility quantitative trait loci (Mts-QTLs) with significant linkage: Mts-1 on chromosome-9 (LOD-2.98) and Mts-2 on chromosome-1 (LOD-2.61), as well as two Mts-QTLs with suggestive linkage: Mts-3 on chromosome-5 (LOD-1.93) and Mts-4 on chromosome-18 (LOD-1.54). Interestingly, Chr9-Mts-1, Chr5-Mts-3 and Chr18-Mts-4 QTLs are unique to irradiation-induced mammary tumorigenesis, while Chr1-Mts-2 QTL overlaps with a mammary cancer susceptibility QTL (Mcs 3) reported for 7,12-dimethylbenz-[α]antracene (DMBA)-induced mammary tumorigenesis in F2[COP x Wistar-Furth]-intercross rats. Altogether, our results suggest at least three distinct susceptibility QTLs for irradiation-induced mammary tumorigenesis not detected in genetic studies of chemically-induced and hormone-induced mammary tumorigenesis. While more study is needed to identify the specific Mts-gene variants, elucidation of specific variant(s) could establish causal gene pathways involved in mammary tumorigenesis in humans, and hence novel pathways for therapy.
RESUMEN Antecedentes: El estado ganglionar axilar, la expresión de los receptores hormonales y del HER2 son importantes factores pro-nóstico en cáncer de mama temprano. El inmunofenotipo triple negativo (HER2 y receptores hormonales negativos) se ha asocia-do con mayor frecuencia de recurrencia y menor tiempo de super-vivencia. El objetivo de esta investigación fue evaluar el compor-tamiento clínico, recurrencia y supervivencia en mujeres con cán-cer de mama temprano-triple negativo y otros inmunofenotipos. Material y métodos: Estudio retrospectivo de mujeres en etapas I-IIB, mayores de 18 años, en quienes se determinó la expresión de la proteína HER2, receptores de estrógeno y de progesterona a través de inmunohistoquímica. Se identificaron cinco grupos: triple negativo, triple positivo, HER2 negativo y receptores hormo-nales positivos, HER2 positivo y receptores hormonales negativos, HER2 negativo y un receptor hormonal positivo. sobrevida global. Resultados: 17 pacientes (15.4%) manifestaron el fenotipo triple negativo; 14 (12.7%), triple positivo; 52 (47.3%) en el grupo 3, 11 (10%) en el 4 y 16 (14.5%) en el grupo 5. El fenotipo triple negativo se asoció con proliferación celular aumentada (p<0.000), menor edad (mediana 43 años), mayor tamaño tumoral (mediana 2.5 cm) y menor proporción de pacientes en etapa I, así como mayor frecuen-cia de expresión positiva de la proteína p53 (78.5%). Observamos mayor frecuencia de recurrencia y de muerte en el grupo triple negativo y en HER2 positivo con receptores hormonales negativos. Conclusiones: El cáncer de mama triple negativo se presenta en mujeres jóvenes y se asocia con proliferación celular aumentada, induce mayor incidencia de recurrencia y de mortalidad. El com-portamiento biológico del cáncer de mama con fenotipo triple negativo es agresivo y similar al observado en pacientes con HER2 positivo y receptores hormonales negativos. Palabras clave: Cáncer de mama, fenotipo triple negativo, estado ganglionar axilar, receptores hormonales SUMMARY Background: Axillary lymph node status, hormonal receptors (HR) and HER2 expression are significant prognostic factors for early breast cancer. Triple negative immunophenotype (HER2 and HR negative) is associated with a high frequency of recurrence and lower overall survival. The objective was assess clinical behavior, recurrence and survival of patients with triple negative early breast cancer and patients with other immunophenotypes. Material and methods: We carried out a retrospective study among women with stages I-IIB over 18 years with determination of HR and HER2 expression by immunohistochemical assay. We identified 5 groups: triple negative, triple positive, HER2 negative & HR positive, HER2 positive & HR negative, HER2 negative & 1 HR positive. We recorded age, date of diagnosis, clinical stage, tumor size, axillary lymph node status, ER, PR, HER2, p53, angiogenesis, Ki67, type of surgery, adjuvant treatment, time to recurrence, number and recurrence site and overall survival. Results: 17 patients (15.4%) had triple negative phenotype, 14 (12.7%) triple positive, 52 (47.3%) were localized in group 3, 11 (10%) in 4 and 16 (14.5%) in group 5. Triple negative phenotype was associated with increased cellular proliferation (p<0.000); being young (median 43 years), large tumor size (median size 2.5 cm) lower proportion of patients in stage I and high frequency of p53 positive (78.5%). We observed a high frequency of recurrence and death among the triple negative group and among the HER2 positive and HR negative cases. Conclusions: Triple negative breast cancer is more common among young women and is associated with a high frequency of recurrence and mortality. Clinical behavior among triple negative breast cancer cases is aggressive and displays a similar clinical profile that observed among HER2 positive and HR negative patients.
Approximately 75 % of extraskeletal myxoid chondrosarcoma tumors (EMC) harbor a t(9;22) chromosome translocation generating an EWS/NR4A3 fusion protein that is thought to be instrumental in the tumoral process. Current evidence suggests that one function of the fusion protein is to overexpress target genes. We have generated an in vitro human cellular model in which the fusion protein is expressed in mesenchymal bone marrow stem cells. We have performed microarray analyses of these cells and identified several genes overexpressed in the presence of EWS/NR4A3 which are also overexpressed in EMC tumors. These genes and their products represent potential therapeutic targets for EMC tumors.
A novel series of N-aryl-N'-pyrimidin-4-yl ureas has been optimized to afford potent and selective inhibitors of the fibroblast growth factor receptor tyrosine kinases 1, 2, and 3 by rationally designing the substitution pattern of the aryl ring. On the basis of its in vitro profile, compound 1h (NVP-BGJ398) was selected for in vivo evaluation and showed significant antitumor activity in RT112 bladder cancer xenografts models overexpressing wild-type FGFR3. These results support the potential therapeutic use of 1h as a new anticancer agent.
To investigate the expression and prognostic significance of EphA2 and EphrinA-1 in ovarian serous carcinomas.
Ninety five tumors from the patients with ovarian serous carcinomas and 2 ovarian cancer cell lines were recruited. The expressions of EphA2 and EphrinA-1 were examined by means of immunohistochemistry. The relationships among protein expression and clinicopathological features, survival of patients were analyzed. The mRNA and protein expressions of EphA2 and EphrinA-1 in ovarian cancer cell lines were measured with semiquantitative polymerase chain reaction and western blotting.
The protein expressions of EphA2 and EphrinA-1 in tumor were 92.6% (88/95)and 97.9% (93/95) respectively, while were 40%(8/20) and 30% (6/20) in adjacent ovarian tissue (P = 0.000). EphA2 immunohistochemical staining could be observed in both tumour and vascular endothelial cells, and EphrinA-1 mainly localized in the tumor cells. The expression of EphA2 was significantly associated with the expression of EphrinA-1 (r = 0.98, P = 0.02). There was no significant correlation between the expressions of EphA2/EphrinA-1 and age, FIGO stage, residual tumour size and histological grade. High levels of both EphA2 and EphrinA-1 protein expression were significantly associated with a shorter overall survival in multivariate analysis (P < 0.05). High levels of EphA2 and EphrinA-1 mRNA and protein were detected in OVCAR3 and SKOV3 cell lines.
There are over-expression of EphA2 and EphrinA-1 in ovarian serous carcinomas and ovarian cancer cell lines. Tumours with higher expression levels of both EphA2 and EphrinA-1 significantly associated with poorer clinical outcome.
Breast cancer is a highly heterogeneous disease, an observation that underscores the importance of elucidating conserved molecular characteristics, such as gene and protein expression, across breast cancer cell types toward providing a greater understanding of context-specific features central to this disease. Motivated by the goal of defining central biological themes across breast cancer cell subtypes, we conducted a global proteomic analysis of three breast cancer cell lines, MCF7, SK-BR-3, and MDA-MB-231, and compared these to a model of nontransformed mammary cells (MCF10A). Our results demonstrate modulation of proteins localized to the extracellular matrix, plasma membrane, and nucleus, along with coordinate decreases in proteins that regulate "cell spreading," a cellular event previously shown to be dysregulated in transformed cells. Protein interaction network analysis revealed the clustering of focal adhesion kinase (FAK), a fundamental regulator of cell spreading, with several proteins identified as mutually, differentially abundant across breast cancer cell lines that impact expression and activity of FAK, such as neprilysin and keratin 19. These analyses provide insights into conservation of protein expression across breast cancer cell subtypes, a subset of which warrants further investigation for their roles in the regulation of cell spreading and FAK in breast cancer.
Purpose
The new classification of malignant fibrous histiocytoma leaves only a small group of tumors without further line of differentiation, so-called pleomorphic sarcomas, not otherwise specified (NOS) as a pseudo-entity. This study focused on these tumors and analyzed the association of gene expression profiles to clinical outcome.
Materials and methods
Ten fresh samples of pleomorphic NOS sarcomas were evaluated histopathologically and by means of microarray analysis. Analysis of expression profiles was performed by clustering methods as well as by statistical analysis of primary vs recurrent tumors, irradiated vs nonirradiated tumors, tumors of patients above and below 60 years of age, male and female, and of tumors that developed metastatic or recurrent disease during the clinical course and those that did not.
Results
Tumor clustering did not correlate to any histopathological or clinical finding. Detailed gene expression analysis showed a variety of genes whose upregulation (platelet-derived growth factor receptor alpha polypeptide, solute carrier family 39 member 14, solute carrier family 2 member 3, pleiotrophin, trophinin, pleckstrin and Sec7 domain containing 3, enolase 2, biglycan, SH3 and cysteine-rich domain, matrix metalloproteinases 16) and whose downregulation (tissue inhibitor of metalloproteinase 4, hairy/enhancer of split related with YRPW motif 2, protein tyrosine phosphatase receptor-type Z polypeptide 1, SH3 domain GRB2-like 2, microtubule-associated protein 7, potassium voltage-gated channel shaker-related subfamily member 1, RUN and FYVE domain containing 3, Sin3A-associated protein 18 kDa, proline-rich 4, calcium/calmodulin-dependent protein kinase ID, myeloid/lymphoid or mixed-lineage leukemia translocated to 3, insulin-like growth factor binding protein 5, nucleoside diphosphate-linked moiety X-type motif 9, NudC domain containing 3, imprinted in Prader–Willi syndrome, TAF6-like RNA polymerase II p300/CBP-associated factor 65 kDa, WD repeat and SOCS box-containing 2, adenosine diphosphate ribosylation factor 3, KRR1, proliferation-associated 2G4; CD36, complement component (3b/4b) receptor 1, solute carrier family 4 sodium bicarbonate cotransporter member 4, lipoprotein lipase (LPL), GATA binding protein 3, LPL, glutathione peroxidase 3, d-aspartate oxidase, apolipoprotein E, sphingomyelin phosphodiesterase acid-like 3A) were associated with poor clinical outcome in terms of development of metastatic or recurrent disease.
Conclusions
The classification of these tumors may undergo further changes in the future. Gene expression profiling can provide additional information to categorize pleomorphic sarcoma (NOS) and reveal potential prognostic factors in this “entity.”
The L1 cell adhesion molecule (L1CAM) belongs to the immunoglobulin superfamily and was originally identified in the nervous system. Recent studies demonstrated L1CAM expression in various types of cancer, predominantly at the invasive front of tumors and in metastases, suggesting its involvement in advanced stages of tumor progression. Overexpression of L1CAM in normal and cancer cells increased motility, enhanced growth rate and promoted cell transformation and tumorigenicity. Moreover, the expression of L1CAM in tumor cells conferred the capacity to form metastases. These properties of L1CAM, in addition to its cell surface localization, make it a potentially useful diagnostic marker for cancer progression and a candidate for anti-cancer therapy. We review the role of L1CAM in cancer progression with particular emphasis on colon cancer, and the potential of anti-L1CAM antibodies as a therapeutic tool for cancer.
Breast cancer is classified based on clinical stage, cellular morphology and immunohistochemical analysis. More precise prognostic factors are necessary to aid with therapeutic decisions. Breast cancer subtypes that differ in their genetic expression and prognosis have been determined using cDNA microarrays. These findings confirm the differences between the phenotypes and provide new knowledge about the biology of breast cancer. Based on the presence or absence of expression of the estrogen receptor (ER), breast cancer is divided in two groups: ER+ and ER-. Genetic expression profile has identified two subtypes of the ER+ tumors: luminal A and luminal B. ER- tumors also include two subtypes, the HER2+ and the basal type. These subtypes differ in their biology and both demonstrate short disease-free periods after treatment and poorer outcome. This classification has shown the relationship between cDNA microarrays and clinical outcome of these tumors. This classification is proposed as a method of identifying those patients who will demonstrate better results with the different adjuvant modalities.
Axillary lymph node status, hormonal receptors (HR) and HER2 expression are significant prognostic factors for early breast cancer. Triple negative immunophenotype (HER2 and HR negative) is associated with a high frequency of recurrence and lower overall survival. The objective was assess clinical behavior, recurrence and survival of patients with triple negative early breast cancer and patients with other immunophenotypes.
We carried out a retrospective study among women with stages I-IIB over 18 years with determination of HR and HER2 expression by immunohistochemical assay. We identified 5 groups: triple negative, triple positive, HER2 negative & HR positive, HER2 positive & HR negative, HER2 negative & 1 HR positive. We recorded age, date of diagnosis, clinical stage, tumor size, axillary lymph node status, ER, PR, HER2, p53, angiogenesis, Ki67, type of surgery, adjuvant treatment, time to recurrence, number and recurrence site and overall survival.
17 patients (15.4%) had triple negative phenotype, 14 (12.7%) triple positive, 52 (47.3%) were localized in group 3, 11 (10%) in 4 and 16 (14.5%) in group 5. Triple negative phenotype was associated with increased cellular proliferation (p < 0.000); being young (median 43 years), large tumor size (median size 2.5 cm) lower proportion of patients in stage I and high frequency of p53 positive (78.5%). We observed a high frequency of recurrence and death among the triple negative group and among the HER2 positive and HR negative cases.
Triple negative breast cancer is more common among young women and is associated with a high frequency of recurrence and mortality. Clinical behavior among triple negative breast cancer cases is aggressive and displays a similar clinical profile that observed among HER2 positive and HR negative patients.
Amplification of loci present on band q13 of human chromosome 11 is a feature of a subset of estrogen receptor positive breast carcinomas prone to metastasis. As many as five distinct amplification units have been described on 11q13. They include particularly a genomic area encompassing the GARP gene at 11q13.5-->q14.1. We have reassessed our current knowledge of this region, located telomeric to CCND1 and EMS1, which is amplified in 7-10% of mammary tumors. The loose definition of the driving forces of these amplification events led us to map accurately the boundaries of the amplifiable region, and thus to contribute a physical and transcriptional map of a 3-Mb region of chromosome 11. Four new genes were placed on the regional map, namely CBP2, CLNS1A, UVRAG, and PAK1. We have narrowed the core of the 11q13-->q14 amplicon to a 350-kb area encompassing D11S533, mostly on its telomeric side. The map reported here represents an indispensable step toward sequencing the entire region, and thus toward uncovering gene(s) which play(s) a critical role in breast cancer progression.
Small GTP-binding proteins of the Rab family play important roles at defined steps of vesicular transport in protein secretion and the endocytosis pathway. In mammals, more than 30 proteins belonging to the Rab family have been reported to date. We report here the molecular cloning and characterization of a novel Rab protein, Rab33B. The amino acid sequence of Rab33B shows 55.3% identity to the Rab33A protein (previously called S10), and these two proteins share unique amino acid sequences at the effector domain. The genomic organization of rab33B was the same as rab33A: it consists of two exons. Thus, these two proteins make a subclass within the Rab family. Northern blot analysis showed that rab33B is expressed ubiquitously in mouse tissues, in contrast to rab33A whose expression is restricted to the brain and the immune system. A 26 kDa protein was detected by western blotting using a Rab33B-specific monoclonal antibody. Using immunofluorescence studies, Rab33B was shown to co-localize with (alpha)-mannosidase II, a Golgi-specific marker. Immunoelectron microscopy analysis further defined the localization of Rab33B to the medial Golgi cisternae. These results suggest Rab33B plays a role in intra-Golgi transport.
Testicular germ-cell tumours (TGCT) affect 1 in 500 men and are the most common cancer in males aged 15-40 in Western European populations. The incidence of TGCT has risen dramatically over the last century. Known risk factors for TGCT include a history of undescended testis (UDT), testicular dysgenesis, infertility, previously diagnosed TGCT (ref. 7) and a family history of the disease. Brothers of men with TGCT have an 8-10-fold risk of developing TGCT (refs 8,9), whereas the relative risk to fathers and sons is fourfold (ref. 9). This familial relative risk is much higher than that for most other types of cancer. We have collected samples from 134 families with two or more cases of TGCT, 87 of which are affected sibpairs. A genome-wide linkage search yielded a heterogeneity lod (hlod) score of 2.01 on chromosome Xq27 using all families compatible with X inheritance. We obtained a hlod score of 4.7 from families with at least one bilateral case, corresponding to a genome-wide significance level of P=0.034. The proportion of families with UDT linked to this locus was 73% compared with 26% of families without UDT (P=0.03). Our results provide evidence for a TGCT susceptibility gene on chromosome Xq27 that may also predispose to UDT.
Desde la Edad Media los monasterios europeos han sido considerados como importantes centros de la cultura y del saber, entre otras razones por las ricas bibliotecas y la valiosa documentación que se guardaba celosamente en el archivo. Los fondos de estas bibliotecas, cuyos responsables supieron conservan durante muchos siglos, fueron engrosándose progresivamente gracias en buena medida a la labor desarrollada pon algunos monjes estudiosos que investigaron sobre diversos temas a partir de la Edad Moderna. Este es el caso de los monjes que profesaron en el monasterio de San Juan de la Peña donde algunos de ellos llevaron a cabo una fructífera carrera profesional como investigadores.
A significant proportion of familial breast cancers cannot be explained by mutations in the BRCA1 or BRCA2 genes. We applied a strategy to identify predisposition loci for breast cancer by using mathematical models to identify early somatic genetic deletions in tumor tissues followed by targeted linkage analysis. Comparative genomic hybridization was used to study 61 breast tumors from 37 breast cancer families with no identified BRCA1 or BRCA2 mutations. Branching and phylogenetic tree models predicted that loss of 13q was one of the earliest genetic events in hereditary cancers. In a Swedish family with five breast cancer cases, all analyzed tumors showed distinct 13q deletions, with the minimal region of loss at 13q21-q22. Genotyping revealed segregation of a shared 13q21 germ-line haplotype in the family. Targeted linkage analysis was carried out in a set of 77 Finnish, Icelandic, and Swedish breast cancer families with no detected BRCA1 and BRCA2 mutations. A maximum parametric two-point logarithm of odds score of 2.76 was obtained for a marker at 13q21 (D13S1308, θ = 0.10). The multipoint logarithm of odds score under heterogeneity was 3.46. The results were further evaluated by simulation to assess the probability of obtaining significant evidence in favor of linkage by chance as well as to take into account the possible influence of the BRCA2 locus, located at a recombination fraction of 0.25 from the new locus. The simulation substantiated the evidence of linkage at D13S1308 (P < 0.0017). The results warrant studies of this putative breast cancer predisposition locus in other populations.
Nucleotide excision repair is a DNA repair pathway that is highly conserved in nature, with analogous repair systems described in Escherichia coli, yeast, and mammalian cells. The rate-limiting step, DNA damage recognition and excision, is effected by the protein products of the genes ERCC1 and XPAC. We therefore assessed mRNA levels of ERCC1 and XPAC in malignant ovarian cancer tissues from 28 patients that were harvested before the administration of platinum-based chemotherapy. Cancer tissues from patients whose tumors were clinically resistant to therapy (n = 13) showed greater levels of total ERCC1 mRNA (P = 0.059), full length transcript of ERCC1 mRNA (P = 0.026), and XPAC mRNA (P = 0.011), as compared with tumor tissues from those individuals clinically sensitive to therapy (n = 15). In 19 of these tissues, the percentage of alternative splicing of ERCC1 mRNA was assessed. ERCC1 splicing was highly variable, with no difference observed between responders and nonresponders. The alternatively spliced species constituted 2-58% of the total ERCC1 mRNA in responders (median = 18%) and 4-71% in nonresponders (median = 13%). These data suggest greater activity of the DNA excision repair genes ERCC1 and XPAC in ovarian cancer tissues of patients clinically resistant to platinum compounds. These data also indicate highly variable splicing of ERCC1 mRNA in ovarian cancer tissues in vivo, whether or not such tissues are sensitive to platinum-based therapy.
The cyclin D1 (PRAD1, CCND1) gene is affected by translocations and amplification in the genomes of a number of human tumors, suggesting that these changes confer growth advantage on developing tumor cell clones. We show here that in cultured cells, a cDNA clone of the cyclin D1 gene can contribute to cell transformation by complementing a defective adenovirus E1A oncogene. In such cells, this candidate oncogene indeed functions like an oncogene, suggesting a similar role in tumor progression in vivo.
Ataxia-telangiectasia (A-T) is a multisystem recessive disease characterized clinically by cerebellar ataxia, oculocutaneous telangiectasias, immunodeficiency, sensitivity to radiomimetic agents, and cancer predisposition. This pleiotropic disorder is caused by mutations in the ATM (mutated in A-T) gene, which is located in the human chromosomal region 11q22-q23. The ATM gene product is a member of a novel family of large proteins implicated in the regulation of the cell cycle and response to DNA damage. Heterozygosity for A-T was previously suggested to be associated with an increased risk of tumors, particularly female breast cancer. Because of loss of constitutional heterozygosity at 11q22-q23 is a frequent event in breast and other tumors, suggesting the presence of a tumor suppressor gene(s) in this region, we screened blood DNA samples from 88 unrelated breast cancer patients of Swedish cancer families for ATM mutations using single-strand conformation polymorphism analysis. All patients had a family history of tumors previously associated with A-T heterozygosity or homozygosity. We demonstrate the first three germ-line mutations in ATM identified by screening of breast cancer patients. Two mutations were previously found in A-T homozygotes and one mutation was a 1-bp insertion. All mutations were found in families with a large number of tumors, however, they did not cosegregate with malignancies. Although the proportion of A-T carriers in this sample seems to be higher than expected by chance, larger studies and pooled data sets will be required to establish that an A-T allele confers cancer susceptibility in heterozygotes.
Transforming growth factor beta (TGF-beta) promotes tumor progression in some model systems including human breast cancer cells. In this study, we report that human breast cancer cell lines express reduced amounts of TGF-beta type III receptor (RIII) when compared with untransformed human mammary epithelial cells. Consequently, we examined whether expression of RIII in human breast cancer MDA-MB-231 cells could reduce TGF-beta's tumor promoting activity by sequestering active TGF-beta isoforms produced by the cells. A tetracycline-repressible human RIII expression vector was stably transfected into the cell line. RIII expression in a pool of transfected clones and a single clone was found to be reversibly repressed by tetracycline treatment. Expression of RIII reduced the amount of active TGF-beta1 and TGF-beta2 in the conditioned medium. The medium conditioned by control cells showed a significantly higher growth inhibitory effect than that conditioned by RIII-transfected cells on the growth of the mink lung epithelial CCL64 cells. A conditioned medium collected from RIII-transfected cells treated with tetracycline significantly increased its growth inhibitory activity to that of control cells. Expression of RIII also reduced tumor incidence and growth rate in two separate experiments when the cells were inoculated in athymic nude mice. Treatment of the mice with tetracycline repressed RIII expression in the tumors generated by RIII-transfected cells and increased tumor incidence and growth rate. These results suggest that TGF-beta RIII can reduce tumorigenicity of MDA-MB-231 cells apparently by sequestering TGF-beta isoforms produced by these cells.
The laminin-gamma1 chain is present in most basement membranes and is involved in various physiological and pathological processes, including carcinogenesis in the liver. We have investigated the role of the transcription factor Sp1 in the activation of the LamC1 gene, which encodes laminin-gamma1, both in hepatocytes and in human hepatocellular carcinomas. DNAse I hypersensitive sites were mapped in the murine LamC1 promoter using early hepatocyte primary cultures in which LamC1 becomes activated. Three hypersensitive sites were found in enhancer-like elements that contain GC-rich regions. Gel-shift analyses showed that specific complexes were resolved using GC-containing oligonucleotides and Faza 567 hepatoma cells, which constitutively express laminin-gamma1 at a high level. Increased GC-binding activity was observed using nuclear extracts from early hepatocyte cultures versus normal liver. Sp1 overexpression in normal hepatocytes transfected with an Sp1 expression vector induced a marked increased of laminin-gamma1 mRNA content and co-transfection of promoter fragments in Drosophila melanogaster SL2 cells demonstrated that Sp1 transactivates LamC1. In human hepatocellular carcinomas, Sp1 and laminin-gamma1 mRNA were simultaneously expressed at high levels, and gel-shift experiments demonstrated a higher GC-binding activity to Sp1 compared with control livers. In situ hybridization indicated that cells exhibiting a high content of laminin-gamma1 mRNA were also strongly positive for Sp1 mRNA, including both cancer cells at the invasion front and stromal cells. These results show that Sp1 is involved in the activation of LamC1 that occurs in human hepatocellular carcinomas.
Neoplasia is characterised by abnormal regulation of the cell cycle. Cyclin D1 is a protein derived from the PRAD1, CCND1 or bcl-1 gene on chromosome 11q13, which is involved in both normal regulation of the cell cycle and neoplasia. In the G1 (resting) phase of the cell cycle, cyclin D1 together with its cyclin dependent kinase (cdk) partner, is responsible for transition to the S (DNA synthesis) phase by phosphorylating the product of the retinoblastoma gene (pRB), which then releases transcription factors important in the initiation of DNA replication. Amplification of the CCND1 gene or overexpression of the cyclin D1 protein releases a cell from its normal controls and causes transformation to a malignant phenotype. Analysis of these changes provides important diagnostic information in mantle cell (and related) lymphomas, and is of prognostic value in many cancers. Knowledge of cyclin D1's role in malignancy at the various sites, provides a basis on which future treatment directed against this molecule can proceed.
Transforming growth factor beta (TGF-beta) can promote late stage tumor progression in a number of model systems. In the present study, we have examined whether expression of a truncated soluble extracellular domain of TGF-beta type III receptor (sRIII) in human breast cancer MDA-MB-231 cells can antagonize the tumor-promoting activity of TGF-beta by sequestering active TGF-beta isoforms that are produced by the cancer cells. The secretion of sRIII reduced the amount of active TGF-beta1 and TGF-beta2 in the conditioned medium. This led to a significant reduction of the growth-inhibitory activity of the medium conditioned by sRIII-expressing cells on the growth of mink lung epithelial CCL64 cells in comparison with the medium conditioned by the control cells. The tumor incidence and growth rate of all of the three sRIII-expressing clones studied were significantly lower than those of the control cells in athymic nude mice. Four of five control cell-inoculated mice showed spontaneous metastasis in the lung, whereas none of the sRIII-expressing cell-inoculated mice had any lung metastasis. Thus, our results suggest that the sRIII may be used to antagonize the tumor-promoting activity of TGF-beta.
A significant proportion of familial breast cancers cannot be explained by mutations in the BRCA1 or BRCA2 genes. We applied a strategy to identify predisposition loci for breast cancer by using mathematical models to identify early somatic genetic deletions in tumor tissues followed by targeted linkage analysis. Comparative genomic hybridization was used to study 61 breast tumors from 37 breast cancer families with no identified BRCA1 or BRCA2 mutations. Branching and phylogenetic tree models predicted that loss of 13q was one of the earliest genetic events in hereditary cancers. In a Swedish family with five breast cancer cases, all analyzed tumors showed distinct 13q deletions, with the minimal region of loss at 13q21-q22. Genotyping revealed segregation of a shared 13q21 germ-line haplotype in the family. Targeted linkage analysis was carried out in a set of 77 Finnish, Icelandic, and Swedish breast cancer families with no detected BRCA1 and BRCA2 mutations. A maximum parametric two-point logarithm of odds score of 2.76 was obtained for a marker at 13q21 (D13S1308, theta = 0.10). The multipoint logarithm of odds score under heterogeneity was 3.46. The results were further evaluated by simulation to assess the probability of obtaining significant evidence in favor of linkage by chance as well as to take into account the possible influence of the BRCA2 locus, located at a recombination fraction of 0.25 from the new locus. The simulation substantiated the evidence of linkage at D13S1308 (P < 0.0017). The results warrant studies of this putative breast cancer predisposition locus in other populations.
Breast cancer cell lines provide a useful starting point for the discovery and functional analysis of genes involved in breast cancer. Here, we studied 38 established breast cancer cell lines by comparative genomic hybridization (CGH) to determine recurrent genetic alterations and the extent to which these cell lines resemble uncultured tumors. The following chromosomal gains were observed: 8q (75%), 1q (61%), 20q (55%), 7p (44%), 3q (39%), 5p (39%), 7q (39%), 17q (33%), 1p (30%), and 20p (30%), and the most common losses were: 8p (58%), 18q (58%), 1p (42%), Xp (42%), Xq (42%), 4p (36%), 11q (36%), 18p (33%), 10q (30%), and 19p (28%). Furthermore, 35 recurrent high-level amplification sites were identified, most often involving 8q23 (37%), 20q13 (29%), 3q25-q26 (24%), 17q22-q23 (16%), 17q23-q24 (16%), 1p13 (11%), 1q32 (11%), 5p13 (11%), 5p14 (11%), 11q13 (11%), 17q12-q21 (11%), and 7q21-q22 (11%). A comparison of DNA copy number changes found in the cell lines with those reported in 17 published studies (698 tumors) of uncultured tumors revealed a substantial degree of overlap. CGH copy number profiles may facilitate identification of important new genes located at the hotspots of such chromosomal alterations. This was illustrated by analyzing expression levels of 1236 genes using cDNA microarrays in four of the cell lines. Several highly overexpressed genes (such as RCH1 at 17q23, TOPO II at 17q21-q22, as well as CAS and MYBL2 at 20q13) were involved in these recurrent DNA amplifications. In conclusion, DNA copy number profiles were generated by CGH for most of the publicly available breast cancer cell lines and were made available on a web site (http://www.nhgri.nih.gov/DIR/CGB/++ +CR2000). This should facilitate the correlative analysis of gene expression and copy number as illustrated here by the finding by cDNA microarrays of several overexpressed genes that were amplified.
The known susceptibility genes for breast cancer, including BRCA1 and BRCA2, only account for a minority of the familial aggregation of the disease. A recent study of 77 multiple case breast cancer families from Scandinavia found evidence of linkage between the disease and polymorphic markers on chromosome 13q21. We have evaluated the contribution of this candidate "BRCA3" locus to breast cancer susceptibility in 128 high-risk breast cancer families of Western European ancestry with no identified BRCA1 or BRCA2 mutations. No evidence of linkage was found. The estimated proportion (alpha) of families linked to a susceptibility locus at D13S1308, the location estimated by Kainu et al. [(2000) Proc. Natl. Acad. Sci. USA 97, 9603-9608], was 0 (upper 95% confidence limit 0.13). Adjustment for possible bias due to selection of families on the basis of linkage evidence at BRCA2 did not materially alter this result (alpha = 0, upper 95% confidence limit 0.18). The proportion of linked families reported by Kainu et al. (0.65) is excluded with a high degree of confidence in our dataset [heterogeneity logarithm of odds (HLOD) at alpha = 0.65 was -11.0]. We conclude that, if a susceptibility gene does exist at this locus, it can only account for a small proportion of non-BRCA1/2 families with multiple cases of early-onset breast cancer.
Solid tumors in humans are now believed to develop through a multistep process that activates oncogenes and inactivates tumor suppressor genes. Loss of heterozygosity at chromosomes 3p25, 3p22-24, 3p21.3, 3p21.2-21.3, 3p14.2, 3p14.3, and 3p12 has been reported in breast cancers. Retinoid acid receptor beta2 (3p24), thyroid hormone receptor beta1 (3p24.3), Ras association domain family 1A (3p21.3), and the fragile histidine triad gene (3p14.2) have been considered as tumor suppressor genes (TSGs) for breast cancers. Epigenetic change may play an important role for the inactivation of these TSGs. Screens for promoter hypermethylation may be able to identify other TSGs in chromosome 3p. Alternatively, use of an "epigenetic modifier" may enhance the response to another type of agent for breast cancer.
Genetic changes underlie tumor progression and may lead to cancer-specific expression of critical genes. Over 1100 publications have described the use of comparative genomic hybridization (CGH) to analyze the pattern of copy number alterations in cancer, but very few of the genes affected are known. Here, we performed high-resolution CGH analysis on cDNA microarrays in breast cancer and directly compared copy number and mRNA expression levels of 13,824 genes to quantitate the impact of genomic changes on gene expression. We identified and mapped the boundaries of 24 independent amplicons, ranging in size from 0.2 to 12 Mb. Throughout the genome, both high- and low-level copy number changes had a substantial impact on gene expression, with 44% of the highly amplified genes showing overexpression and 10.5% of the highly overexpressed genes being amplified. Statistical analysis with random permutation tests identified 270 genes whose expression levels across 14 samples were systematically attributable to gene amplification. These included most previously described amplified genes in breast cancer and many novel targets for genomic alterations, including the HOXB7 gene, the presence of which in a novel amplicon at 17q21.3 was validated in 10.2% of primary breast cancers and associated with poor patient prognosis. In conclusion, CGH on cDNA microarrays revealed hundreds of novel genes whose overexpression is attributable to gene amplification. These genes may provide insights to the clonal evolution and progression of breast cancer and highlight promising therapeutic targets.
Estrogen receptor-mediated transcription is enhanced by overexpression of G1/S cyclins D1, E or A in the presence as well in the absence of estradiol. Excess of G1/S cyclins also prevents the inhibition of transactivation of estrogen receptor (ER) by the pure antiestrogen ICI 182780. Cyclin D1 mediates this transactivation independent of complex formation to its CDK4/6 partner. This raises the possibility that overexpression of G1/S cyclins renders growth of ER-positive breast cancer hormone-independent and resistant to treatment with antiestrogens. Transient transfection of ER-positive breast cancer cell lines T47D and MCF7 with G1/S cyclins could overcome the growth arrest induced by ICI 182780 treatment. The ability of various cyclin D1 mutants to overcome the ICI 182780 mediated growth arrest corresponded with their ability to stimulate cyclin A- and E2F- promoter based reporter activities in the presence of ICI 182780. Transfection of a mutant cyclin D1 (cyclin D1-KE) that was unable to bind CDK4 and was reported to transactivate ER in the presence of ICI 182780, could not stimulate proliferation in ICI 182780 treated cells. On the other hand, cyclin D1-LALA, which is unable to stimulate ERE transactivation, could overcome the ICI 182780 cell cycle arrest. Furthermore, transient transfection of T47D cells using cyclin D1 together with a catalytic inactive mutant of CDK4 (CDK4-DN) indicated that the observed effect is due to binding to CDK inhibitors. However, a moderate, sixfold overexpression of cyclin D1 in stably transfected MCF7 cells did not overcome the ICI 182780 mediated growth arrest. These results indicate that CDK-independent transactivation of the estrogen receptor by cyclin D1 is by itself, not sufficient to result in estradiol-independent growth of breast cancer cells, whereas a vast overexpression of G1/S cyclins is able to do so, most likely by capturing of CDK inhibitors.
Multiple chromosomal imbalances have been identified in breast cancer using comparative genomic hybridization (CGH). Their association with the primary tumors' potential for building distant metastases is unknown. In this study we have investigated 39 invasive breast carcinomas with a mean follow-up period of 99 months (max. 193 months) by CGH to determine the prognostic value of chromosomal gains and losses. The mean number of chromosomal imbalances per tumor was 6.5+/-0.7 (range 2 to 18). The most frequent alterations identified in more than 1/3 of cases were gains on chromosomes 11q13, 12q24, 16, 17, and 20q, and losses on 2q and 13q. A significantly different frequency of chromosomal aberrations (p<or=0.05) was found between DNA-diploid and non-diploid tumors (gain on chromosome 17). Differences were also noted between tumors progressing to distant metastases within the period of follow-up and those which do not (gains on 11q13 and 12q24; loss on 12q). Significant univariate correlations (p<or=0.05) with the metastasis-free survival of patients were found for lymph node status, the cytometrical determined DNA ploidy (diploid/non-diploid) and anisokaryosis, and for DNA gains on 11q13, 12q24, 17, and 18p. An unexpected inverse correlation was found between clinical outcome and gains on 11q13 and 12q24. In multivariate analysis independent prognostic value, in addition to lymph node status, was found for chromosomal gains on 11q13, 12q24, 17 and 18p. Amplification on 20q, which did not correlate with metastasis-free survival in a univariate analysis, showed weak prognostic significance in combination with the nodal status. The prognostic value of chromosomal alterations - some of them by inverse correlation - suggests an interaction and/or compensation of the involved amplified genes and their effects on the occurrence of distant metastases in breast cancer patients.
The protein p53 is the most frequently mutated tumour suppressor to be
identified so far in human cancers,. The ability of p53 to inhibit cell
growth is due, at least in part, to its ability to bind to specific DNA
sequences and activate the transcription of target genes such as that
encoding the cell-cycle inhibitor p21Waf1/Cip1 (ref. 3). A
gene has recently been identified that is predicted to encode a protein
with significant amino-acid sequence similarity to p53 (ref. 4). In
particular, each of the p53 amino-acid residues implicated in direct
sequence-specific DNA binding is conserved in this protein. This gene,
called p73, maps to the short arm of chromosome 1, and is found in a
region that is frequently deleted in neuroblastomas. Here we show that
p73 can, at least when overproduced, activate the transcription of
p53-responsive genes and inhibit cell growth in a p53-like manner by
inducing apoptosis (programmed cell death).
Determination of HER-2/neu oncogene amplification has become clinically important in the present management of breast cancer and may have important applications in other areas of clinical oncology and scientific research. In situ hybridization is an extremely accurate and sensitive technique for assessing amplification of HER-2/neu. A new method using a chromogen-labeled probe offers numerous advantages, including the ability to view the morphologic features of the cells of interest using a light microscope, which can be found in every laboratory. We used both techniques to assay 31 cases of infiltrating breast carcinoma; assays were performed in laboratories at 2 institutions. Identical results for both methods were found in 26 cases (10 amplified, 16 nonamplified). One case was misinterpreted as overexpressed by chromogenic in situ hybridization (CISH) because of background precipitate. In 4 cases, CISH suggested low-level amplification. Three of these cases subsequently were found to have chromosome 17 polysomy. In the remaining case, the initial section chosen was suboptimal, showing weak signals by both methods. If a probe for chromosome 17 (now available for CISH) is used in cases of questionable HER-2/neu amplification, CISH seems to be as accurate and more practical than FISH.
Interleukin (IL)-12 was cloned on the basis of its ability to activate natural killer (NK) cells and promote the development of cytolytic T cells. With further understanding of its activities, IL-12 has emerged as an important cytokine, affecting both immune and hematologic functions. It has been shown to be necessary for the T cell independent induction of interferon (IFN)-γ, critical for the initial suppression of bacterial and parasitic infection; for the development of a Th1 response, critical for effective host defense against intracellular pathogens; and for the activation of differentiated T lymphocytes of both CD4+ and CD8+ phenotype. IL-12 thus functions to activate and to link the innate and acquired immune responses. The therapeutic potential of these activities is suggested by studies in tumor and microbial models. IL-12 has suppressed tumor growth in all murine models examined. Antimicrobial activity has been demonstrated in bacterial, yeast, parasitic, and viral models of infection. In many of these models, activity has been linked to production of IFN-γ and, in the parasite model, to development of a Th1 response. In addition to the therapeutic potential associated with IL-12 activity in these disease models, the understanding of its role in immune development and interaction with other cytokines, particularly antagonists, such as IL-4 and IL-10, has clarified and extended our understanding of immune regulation and should lead to significant developments in understanding the progression of AIDS and the development of vaccine adjuvants able to direct the immune response.
A preparative method for isolating high-molecular-weight DNA from animal cells is described. This method is based on the use of proteinase K, a powerful proteolytic enzyme with a broad action spectrum, which is very active in the presence of sodium dodecylsulfate and ethylene-diamine tetraacetate. The DNA preparation is free of RNA, protein and degrading enzymes. The number-average molecular weight of the native DNA is 190 × 106, whereas it is 90 × 106 for single-stranded DNA, indicating that the DNA molecules do not contain single-stranded nicks. The native DNA molecules range in molecular weight from 40 × 106 to more than 500 × 106.
The biology of the fibroblast growth factor (FGF) gene family is reviewed. The structure, expression and known and putative functions of the seven members of this family characterized to date are discussed. These genes include: acidic and basic FGF, the INT.2 and HST proto-oncogenes and the recently characterized FGF.5, FGF.6 and KGF genes. These genes play a role in various processes such as cell proliferation, angiogenesis and embryogenesis, and possibly carcinogenesis.
int-2 was discovered as a proto-oncogene transcriptionally activated by MMTV proviral insertion during mammary tumorigenesis in the mouse. Sequence analysis showed int-2 to be a member of the fibroblast growth factor family of genes. In normal breast and most other adult mouse tissues, int-2 expression was not detected except for low levels in brain and testis. However, using in situ hybridization, expression was found at a number of sites during embryonic development, from day 7 until birth. An analysis of the int-2 transcripts found in embryonal carcinoma cells revealed six major classes of RNA initiating at three promoters and terminating at either of two polyadenylation sites. Despite the transcriptional complexities, all size classes of RNA encompass the same open reading frame. Using an SV40 early promoter to drive transcription of an int-2 cDNA in COS-1 cells, several proteins were observed. These were shown to be generated by initiation from either of two codons: One, a CUG, leads to a product which localizes extensively to the cell nucleus and partially to the secretory pathway. In contrast, initiation at a downstream AUG codon results in quantitative translocation across the endoplasmic reticulum and the accumulation of products ranging in size from 27.5 x 10(3) Mr to 31.5 x 10(3) Mr in organelles of the secretory pathway. These proteins represented glycosylated and non-glycosylated forms of the same primary product with or without the signal peptide removed. These findings suggest the potential for a dual role of int-2; an autocrine function acting at the cell nucleus, and a possible paracrine action through a secreted product.
The genetic disease xeroderma pigmentosum (XP) demonstrates the association between defective repair of DNA lesions and cancer. Complementation analysis performed on XP cell strains and on repair deficient rodent cell lines has revealed that at least nine and possibly more than 13 genes are involved in early steps of the excision of ultraviolet light-induced DNA lesions in mammalian cells. Two of these genes have been cloned and others are in an advanced stage of cloning. One cloned gene, ERCC-1, has been characterized at the molecular level. This human gene is homologous with excision repair genes in yeast and in Escherichia coli. These results indicate that the excision repair system is conserved during evolution. It is expected that the cloning and characterization of prokaryotic and eukaryotic repair genes will pave the way to a deeper understanding of mammalian repair systems and their association with cancer.
GADD45 is a ubiquitously expressed mammalian gene that is induced by DNA damage and certain other stresses. Like another p53-regulated gene, p21WAF1/CIP1, whose product binds to cyclin-dependent kinases (Cdk's) and proliferating cell nuclear antigen (PCNA), GADD45 has been associated with growth suppression. Gadd45 was found to bind to PCNA, a normal component of Cdk complexes and a protein involved in DNA replication and repair. Gadd45 stimulated DNA excision repair in vitro and inhibited entry of cells into S phase. These results establish GADD45 as a link between the p53-dependent cell cycle checkpoint and DNA repair.
The FAU gene (FBR-MuSV associated ubiquitously expressed gene) encodes the ribosomal protein S30 fused with a Ubiquitin-like
molecule. The FAU gene is expressed in a wide range of tissues, is evolutionarily conserved, and has putative tumour suppressor
activity in vitro. The human FAU gene maps to the long arm of chromosome 11 band q13, close to the PYGM locus. This locus is tightly linked
to the Multiple Endocrine Neoplasia type 1 (MEN1) locus. The FAU gene properties, together with its chromosomal localisation
on 11q13, make it a candidate gene for MEN1. To test this hypothesis we screened 33 unrelated patients with MEN1 for constitutional
genetic alterations in the FAU gene by Southern blot analysis, denaturing gradient gel electrophoresis (DGGE) and in two cases
complemented by DNA sequencing to confirm the DGGE data. Furthermore, 10 parathyroid and pancreatic tumours from MEN1 patients
and 15 each of sporadic parathyroid and pituitary tumours were similarly examined. In addition, we studied the expression
of the FAU gene at the RNA level in 9 MEN1-associated tumours by Northern blot analysis. No FAU gene anomalies could be demonstrated
by any of these techniques. We conclude that FAU is not likely to be the MEN1 tumour suppressor gene.
We have characterized a new human gene, named GARP, localized in the 11q14 chromosomal region. GARP comprises two coding exons, is expressed as two major transcripts of 4.4 and 2.8 kilobases, respectively, and encodes a putative transmembrane protein of 662 amino acids, the extracellular portion of which is almost entirely made of leucine-rich repeats. The molecular weight of the protein immunoprecipitated from transfected cells is 80,000. The GARP protein has structural similarities with the human GP Ib alpha and GP V platelet proteins, and with the Chaoptin, Toll, and Connectin adhesion molecules of Drosophila.
The human Gi-phase cyclins are important regulators of cell cycle progression that interact with various cyclin-dependent kinases and facilitate entry into S-phase. We have confirmed the localization of the human cyclin C (CCNC) gene to chromosome 6q21 and of human cyclin E (CCNE) to 19q12. The CCNC gene structure was also determined, and we have shown that it is deleted in a subset of acute lymphoblastic leukemias, including a patient sample containing a t(2;6)(p21;q15), with no apparent cytogenetic deletion. Single-strand conformational polymorphism analysis of the remaining CCNC allele from patients with a deletion of one allele established that there were no further mutations within the exons or the flanking intronic sequences. These results suggest either that haploinsufficiency of the cyclin C protein is sufficient to promote tumorigenesis or that the important tumor suppressor gene is linked to the CCNC locus.
Tumor necrosis factor (TNF) is a powerful cytokine which is involved in the immune and pro-inflammatory response. The TNF receptors (TNF-R1 and TNF-R2) are the sole mediators of TNF signaling. The receptors consist of a disulfide rich domain which recognizes TNF, a transmembrane helix, and a cytoplasmic domain. Signaling occurs when a TNF trimer binds two or three receptors in an extracellular complex which permits aggregation and activation of the cytoplasmic domains. The complex is then endocytosed where it dissociates at low pH. We have now determined the structure of the soluble extracellular domain of TNF-R1 in two crystal forms at pH 3.7 in addition to our earlier report of one form at pH 7.5. One low pH form diffracts to 1.85 A and the entire polypeptide sequence has now been traced for this protein. The C-terminal 20 residues of the protein which were disordered in all previous structures show a different topology and disulfide connectivity to that seen in the remainder of the structure. In all crystal forms, the uncomplexed soluble extracellular domain of the type I TNF-R (sTNF-R1) exists as a dimer. At low pH the dimer buries a large amount of solvent accessible surface (2,900 A2), over 800 A2 greater than the area buried by TNF complexation. This dimer at low pH is different than both dimers observed in our previous pH 7.5 structure of unliganded sTNF-R1. We suggest that the low pH dimer forms during endocytosis and as the dimer completely buries the TNF interaction surface, the dimer would break up the receptor TNF complex. We have identified two distinct structural modules in sTNF-R1, a type A and a type B module. We suggest that these modules are the unit of structural conservation rather than the 6 cysteine subdomain. Although the orientation of these modules with respect to each other is sensitive to crystal packing, complexation, and pH, the modules themselves are structurally well conserved between and within the known sTNF-R1 structures. This modular approach will allow us to build accurate models for all members of the TNF-R superfamily.
The protein p53 is the most frequently mutated tumour suppressor to be identified so far in human cancers. The ability of p53 to inhibit cell growth is due, at least in part, to its ability to bind to specific DNA sequences and activate the transcription of target genes such as that encoding the cell-cycle inhibitor p21Waf1/Cip1 . A gene has recently been identified that is predicted to encode a protein with significant amino-acid sequence similarity to p53. In particular, each of the p53 amino-acid residues implicated in direct sequence-specific DNA binding is conserved in this protein. This gene, called p73, maps to the short arm of chromosome 1, and is found in a region that is frequently deleted in neuroblastomas. Here we show that p73 can, at least when overproduced, activate the transcription of p53-responsive genes and inhibit cell growth in a p53-like manner by inducing apoptosis (programmed cell death).
The cyclin D1/CCND1 oncogene (PRAD1) is amplified in 15% of primary human breast cancers and overexpressed in 30-50% of breast cancers, suggesting that mechanisms in addition to DNA amplification may lead to deregulated expression of this gene in breast cancer. Cyclin D1 overexpression at a higher frequency than gene amplification is also seen in a variety of other tumors. Cyclin D1 overexpression without amplification could result from a trans-acting regulatory disturbance or could be a consequence of a clonal regulatory mutation in one allele of the gene. We have, therefore, examined whether the overexpression of cyclin D1 mRNA is derived from one parental allele or both alleles in tumor cell lines with or without amplification of the cyclin D1 gene. Eight tumor cell lines, MCF-7, SK-BR-3, ZR-75-1, U-2-OS, SK-LMS-1, DLD1, HCT15, and HT29, out of 20 tumor cells initially examined were found to be heterozygous at the polymorphic NciI site within exon 4 of the cyclin D1 gene. Polymerase chain reaction and NciI digestion (PCR-RFLP) analysis of genomic DNA demonstrated DNA amplification of one allele in the ZR-75-1 cells and HT29 cells and no such imbalance in cyclin D1 gene copy number in the other cells, consistent with Southern blot analyses. Reverse-transcription polymerase chain reaction analysis and NciI digestion (RT-PCR-RFLP) of total cDNA revealed that the overexpressed cyclin D1 mRNA is preferentially derived from the amplified allele in the ZR-75-1 and HT29 cells. In contrast, the other tumor cells overexpressed cyclin D1 mRNA equally from both alleles. This finding strongly suggests that, in breast, sarcoma, and in colon cancer cells with cyclin D1 overexpression and normal gene copy number, elevated levels of cyclin D1 mRNA result from a trans-acting influence on both alleles rather than a clonal somatic mutation or rearrangement in or near a single cyclin D1 gene.
Interleukin-12 (IL-12) is a heterodimeric cytokine that plays a central role in promoting type 1 T helper cell (Th1) responses and, hence, cell-mediated immunity. Its activities are mediated through a high-affinity receptor composed of two subunits, designated beta 1 and beta 2. Of these two subunits, beta 2 is more restricted in its distribution, and regulation of its expression is likely a central mechanism by which IL-12 responsiveness is controlled. Studies with neutralizing anti-IL-12 antibodies and IL-12-deficient mice have suggested that endogenous IL-12 plays an important role in the normal host defense against infection by a variety of intracellular pathogens. However, IL-12 appears also to play a central role in the genesis of some forms of immunopathology. Inhibition of IL-12 synthesis or activity may be beneficial in diseases associated with pathologic Th1 responses, such as multiple sclerosis or Crohn's disease. On the other hand, administration of recombinant IL-12 may have utility in the treatment of diseases associated with pathologic Th2 responses such as allergic disorders and asthma.
Mutation of Caspase 9 (Casp9) results in embryonic lethality and defective brain development associated with decreased apoptosis. Casp9-/- embryonic stem cells and embryonic fibroblasts are resistant to several apoptotic stimuli, including UV and gamma irradiation. Casp9-/- thymocytes are also resistant to dexamethasone- and gamma irradiation-induced apoptosis, but are surprisingly sensitive to apoptosis induced by UV irradiation or anti-CD95. Resistance to apoptosis is accompanied by retention of the mitochondrial membrane potential in mutant cells. In addition, cytochrome c is translocated to the cytosol of Casp9-/- ES cells upon UV stimulation, suggesting that Casp9 acts downstream of cytochrome c. Caspase processing is inhibited in Casp9-/- ES cells but not in thymocytes or splenocytes. Comparison of the requirement for Casp9 and Casp3 in different apoptotic settings indicates the existence of at least four different apoptotic pathways in mammalian cells.
The deletion of region 36 in the short arm of chromosome 1 (1p36) was investigated in 18 patients with oral squamous cell carcinoma by means of the double-target fluorescence in situ hybridization (FISH) method. 1p36 has been suggested to harbor a putative tumor suppressor gene, and thought to carry several genes such as p58, FRAP and TNF-R II. The deletion of 1p36 may play a part in cell regulation, apotosis, promotion and progression of carcinoma cells. The double-target FISH was completed by the use of a biotin-labeled chromosome 1 centromeric repetitive probe and a digoxigenin-labeled 1p36 probe in biopsied specimens obtained from these patients before the treatment. The ploidy pattern of the nuclear DNA of these specimens was also examined by flow cytometry. The deletion of 1p36 was observed in 3 patients with poor prognosis showing aneuploidy in their nuclear DNA. These results may indicate that the deletion of 1p36 can be a reliable factor in the poor prognosis of patients with oral squamous cell carcinoma.
By screening for differentially expressed genes in cancer cells, using the RNA differential display (DD) technique, we identified a novel cDNA, LDOC1, that is down-regulated in some cancer cell lines. A Northern blot analysis revealed no expression in pancreatic and gastric cancer cell lines but ubiquitous expression in normal human tissues. This new gene was mapped on chromosome Xq27 and the predicted protein sequence showed no similarity to known sequences in the database except for a leucine zipper-like motif at the N-terminal region and a proline-rich region that shares marked similarity to an SH3-binding domain. In an enhanced green fluorescent protein (EGFP) assay, the EGFP-LDOC1 fusion protein was localized in the nucleus. Although the function of LDOC1 is still unknown, our results suggest that this novel gene codes for a nuclear protein, and down-regulation of LDOC1 may have an important role in the development and/or progression of some cancers.
We have developed a protocol for degenerate oligonucleotide-primed-polymerase chain reaction-based array comparative genomic hybridization (array CGH) that, when combined with a laser microdissection technique, allows the analysis of cancer cell populations isolated from routine, formalin-fixed, paraffin-embedded tissue samples. Comparison of copy number changes detected by degenerate oligonucleotide-primed-polymerase chain reaction-based array CGH to those detected by conventional array CGH or fluorescence in situ hybridization, demonstrated that amplifications can be reliably detected. Using a genomic microarray containing 57 oncogenes, we screened a total of 28 breast cancer samples and obtained a detailed amplicon profile that is the most comprehensive to date in human breast cancer. The array CGH method described here will allow the genetic analysis of paraffin-embedded human cancer materials for example in the context of clinical trials.
As a result of substantial advances in recent cancer biology, cell cycle regulation in the G1 phase has attracted a great deal of attention as a promising target for the research and treatment of cancer. Many of the important genes associated with G1 regulation have been shown to play a key role in proliferation, differentiation and oncogenic transformation and programmed cell death (apoptosis). Currently, a variety of "cytostatic" agents that affects G1 progression and/or G1/S transition are being evaluated in clinical trials. Flavopiridol is a potent inhibitor of cyclin-dependent kinases (CDKs). UCN-01 was originally found to be a PKC-selective protein kinase antagonist. More recent studies have revealed that this agent can also inhibit several CDKs and the checkpoint kinase CHK1. FR901228, MS-27-275 and SAHA are histone deacetylase inhibitors that induce changes in the transcription of specific genes via the hyperacetylation of histones. The proteasome inhibitor PS-341 disrupts the degradation process of intracellular proteins, including cell cycle regulatory proteins such as cyclins. R115777, SCH66336 and BMS-214662 are non-peptidic farnesyl transferase inhibitors that prevent p21 ras oncogene activation. Rapamycin derivative CCI-779 downregulates signals through S6 kinase and FRAP (FKBP-rapamycin associating protein), affecting the expression levels of mRNAs important for progression from G1 to S phase. 17-Allylaminogeldanamycin targets the Hsp-90 (heat shock protein-90) family of cellular chaperones regulating the function of signaling proteins. TNP-470 (AGM-1470), a fumagillin derivative shows antiangiogenic action through binding to MetAP-2 (methionine aminopeptidase-2). The antitumor sulfonamide E7070, causing a cellular accumulation in the G1 phase, has been shown to suppress the activation of CDK2 and cyclin E expression in HCT116 colorectal cancer cell line highly sensitive to the drug. With respect to several growth factor receptors such as EGFR, PDGFR, bFGFR and VEGFR, potent and specific inhibitors of receptor tyrosine kinases have been also examined as hopeful drug candidates. In this report, we review the current status of extensive efforts directed towards the discovery and development of new chemotherapeutic anticancer agents targeting cell cycle regulation in the G1 phase, with particular focus on the compounds undergoing clinical investigations.
Alterations in gene expression represent key events in carcinogenesis. We have studied HPV-induced cervical carcinogenesis, using an HPV-33-positive cell line (UT-DEC-1) established from a low-grade vaginal dysplasia (VAIN-I). Early-passage cells contained HPV-33 in episomal form, but these were superseded at later passages by cells carrying only integrated virus. To gain insight into the biologic significance of HPV integration, we compared the level of gene expression in normal vaginal keratinocytes, early-passage and late-passage UT-DEC-1 cells, using cDNA microarrays. Total RNA was isolated from cells by CsCl-gradient centrifugation, reverse-transcribed with MMLV reverse transcriptase and labeled with alpha-(32)P ATP. A cDNA microarray expression profile analysis was performed with Clontech's Human Cancer 1.2 cDNA expression array kit. The 16 upregulated genes (cut-off 2-fold), identified by comparing both cell types to control keratinocytes, appeared to support cell-cycle progression or to be functional in mitosis. These included, e.g., MCM4 DNA replication licensing factor, cdc2p34 and chromatin assembly factor 1 p48 subunit. Downregulated genes (44 altogether) interfered with apoptosis and cell adhesion, including the apoptosis-inducing genes FRAP, Bik and caspase-9 precursor. The most significant differences between the late and early passages (29 and 46 constantly up- and downregulated genes without any fluctuation) were overexpression of the transcription factors E2F5 with its dimerization partner DP1, NF-kappa B and serine/threonine kinases and underexpression of enzymes of the MAPK pathway. Acquisition of a selective growth advantage after viral integration might be explained by a major shift from a MAPK pathway to cell-cycle dysregulation (G(2)/M).
Breast cancer has a high incidence and associated mortality rate, yet little is known of the sequence of genetic events that underlie the clinical course.
The study was a comparative genomic hybridization analysis of 40 primary breast cancers with survival data at a mean of 8.4 years.
The mean number of aberrations was 9.0, with a mean of 5.5 gains and 3.5 deletions per tumour. The most common aberrations were: gain of 1q (27 of 40), 8q (19 of 40) and 17q (13 of 40), and deletion of 17p (12 of 40) and 8p (11 of 40). These results are consistent with a distinctive pattern of large-scale (karyotypic) genetic change in primary breast cancer.
The novel findings of this study were that only women who were disease-free had loss of 16q (E-cadherin) in association with a gain of 16p, and 17p13 (p53) loss combined with 17q12 (HER2) amplification was found only in the cancers of women who developed recurrent disease. The karyotypic changes seen in primary breast cancer seem to be associated with outcome and point to the underlying genetic events.
Determination of HER-2/neu oncogene amplification has become clinically important in the present management of breast cancer and may have important applications in other areas of clinical oncology and scientific research. In situ hybridization is an extremely accurate and sensitive technique for assessing amplification of HER-2/neu. A new method using a chromogen-labeled probe offers numerous advantages, including the ability to view the morphologic features of the cells of interest using a light microscope, which can be found in every laboratory. We used both techniques to assay 31 cases of infiltrating breast carcinoma; assays were performed in laboratories at 2 institutions. Identical results for both methods were found in 26 cases (10 amplified, 16 nonamplified). One case was misinterpreted as overexpressed by chromogenic in situ hybridization (CISH) because of background precipitate. In 4 cases, CISH suggested low-level amplification. Three of these cases subsequently were found to have chromosome 17 polysomy. In the remaining case, the initial section chosen was suboptimal, showing weak signals by both methods. If a probe for chromosome 17 (now available for CISH) is used in cases of questionable HER-2/neu amplification, CISH seems to be as accurate and more practical than FISH.
Breast tumors display a wide variety of genomic alterations. This review focuses on DNA copy number variations in these tumors as measured by the recently developed microarray-based form of comparative genomic hybridization. The capabilities of this new technology are reviewed. Initial applications of array CGH to the analysis of breast cancer, and the mechanisms by which the particular types of copy number changes might arise are discussed.
Nearly 30% of the breast cancer patients in the Taiwanese community have their diseases diagnosed before the age of 40. Their 5-year survival rate is poorer than that of their late-onset breast cancer counterparts. Genomic abnormalities between these two breast cancer age groups were compared using comparative genomic hybridization (CGH) analyses. The sample set was made up of 44 early-onset (<35 years old) and 54 late-onset cases (>63 years old). Frequent CGH changes were noted, such as gains on 8q, 1q, and 17q and losses on 16q, 17p, and 8p. These were very similar for the two age groups, as well as for Taiwanese women and other ethnic populations. In contrast, several less common lesions, such as gains on 16p and 8p and losses on 11q and 9p, were significantly different between the early- and late-onset breast tumors. In addition, more profound chromosomal changes were consistently associated with the more advanced-stage tumors, and less expression of the estrogen and the progesterone receptors, and of HER-2/neu. About 19% of the breast cancers examined carried a TP53 mutation in exons 4-9. Of these, 88% (15/17) were missense point mutations and these were distributed randomly along the tested gene fragments without apparent clustering, as has been shown in certain other ethnic or regional studies. On average, patients carrying these TP53 mutations had 9.5 CGH lesions per case, compared to only 2.8 changes in samples that had no TP53 mutation. Our results indicate that certain genomic lesions, especially 11q loss, may play a role in early-onset breast tumor formation, and that combined use of genomic patterns and molecular targets may provide a useful tool for diagnostic, therapeutic, and prognostic purposes.
p53 mutation is associated with poor prognosis in breast cancer patients. Mutations in different structural and functional domains of p53 have different effects on its biological activities. Nevertheless, few studies have examined the full spectrum of p53 gene mutations in relation to breast cancer survival.
To evaluate the prognostic significance of the types, localizations, and multiplicity of p53 gene mutations in breast cancer patients.
Prospective cohort study of a consecutive series of 271 women with histologically confirmed primary breast cancer who underwent breast resection at the Jackson Memorial Hospital, Miami, FL, between 1984 and 1986. Main outcome measures. Ten year overall and breast-cancer-specific deaths.
After adjustment for tumor stage, treatment regimen, and the number of mutations, patients with p53 mutations had significantly greater breast-cancer-specific mortality than did patients without p53 mutations (hazard ratio = 2.86; 95% confidence interval: 1.15-7.11). Further analysis of mutation characteristics showed that patients with the following mutations had significantly poorer breast cancer disease-free survival: silent/missense mixed mutations (7.95; 1.28-49.62), nonsense mutations (9.43; 1.29-69.12), transitions (3.79; 1.46-9.88), mutations in which guanine changed (3.32; 1.01-10.35), and mutations on exon 7 (6.46; 1.78-23.45).
Breast-cancer-specific and all-cause mortality are increased in female breast cancer patients with the following p53 mutation characteristics: silent and missense mixed mutations, transitional mutations, mutations in which guanine changed, mutations on exon 7, or multiple mutations occurring within 60 codons. These findings indicate that not just p53 mutation per se but the full spectrum (i.e., different types, locations, and numbers) of p53 mutation needs to be examined when it is used as a prognostic marker of survival in breast cancer patients.
Breast cancer is the second leading cause of death in women older than 35 years in Mexico. In this study, we used comparative genomic hybridization (CGH) to analyze sporadic breast cancers at stages II and III from untreated patients. We obtained 4.1 chromosomal alterations per sample, less than in previous reports. We identified a small region in Xq27 with high-level amplification in 3 of 16 samples. This amplification has been reported only in pancreatic and gastric cancer cell lines and in testis tumors; in addition, this amplification had been reported in one primary breast cancer, but in a more extended region that we identified. We also identified a loss in 2p13, not previously reported in this neoplasia. The most frequent alterations were amplifications in 4q, 5q, 8q, 12p, and 13q and losses in 1p, 8p, 16p, 19q, and Xp. CGH provides data for better understanding of molecular events in this neoplasia.
The candidate human tumor suppressor gene cyclin C is a primary target of the anti-proliferative hormone 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], but binding sites for the 1α,25(OH)2D3 receptor (VDR), so-called 1α,25(OH)2D3 response elements (VDREs), have not yet been identified in the promoter of this gene. We screened various cancer cell lines
by quantitative PCR and found that the 1α,25(OH)2D3 inducibility of cyclin C mRNA expression, in relationship with the 24-hydroxylase (CYP24) gene, was best in MCF-7 human breast cancer cells. To characterize the molecular mechanisms, we analyzed 8.4 kb of the cyclin C promoter by using chromatin immunoprecipitation assays (ChIP) with antibodies against acetylated histone 4, VDR and its partner
receptor, retinoid X receptor (RXR). The histone 4 acetylation status of all 23 investigated regions of the cyclin C promoter did not change significantly in response to 1α,25(OH)2D3, but four independent promoter regions showed a consistent, 1α,25(OH)2D3-dependent association with VDR and RXR over a time period of 240 min. Combined in silico/in vitro screening identified in each of these promoter regions a VDRE and reporter gene assays confirmed their functionality. Moreover,
re-ChIP assays monitored simultaneous association of VDR with RXR, coactivator, mediator and RNA polymerase II proteins on
these regions. Since cyclin C protein is associated with those mediator complexes that display transcriptional repressive
properties, this study contributes to the understanding of the downregulation of a number of secondary 1α,25(OH)2D3-responding genes.