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A human oncogene formed by the fusion of truncates tropomyosin and protein kinase sequences
Abstract
A biologically active complementary DNA clone of a transforming gene present in a human colon carcinoma contains gene sequences of both tropomyosin and a previously unknown protein tyrosine kinase. The predicted protein (641 amino acids) encoded by this oncogene seems to have been formed by a somatic rearrangement that replaced the extracellular domain of a putative transmembrane receptor by the first 221 amino acids of a non-muscle tropomyosin molecule.
... However, TRKs can be constitutively activated via NTRK gene fusions in the pathogenesis of human malignant cancers, in which the 3 0 region of the NTRK gene, including the kinase domain, achieves an in-frame fusion to the 5 0 sequence of fusion partner gene 5,6 . The first NTRK fusion gene TPM3-NTRK1 was discovered in human colorectal carcinoma in 1982 7,8 , and to date, over 100 different NTRK fusion partners have been identified in various cancers 9,10 . TRK proteins have been considered as attractive "pan-cancer" targets for the treatment of various cancers harboring NTRK fusions 11 . ...
... Driving by the 5 0 upstream partner, the NTRK chimeric oncoprotein can be constitutively activated through a ligand-independent manner, leading persistent activation of TRK downstream signaling pathways and high risks of oncogenesis 50e52 . Since the first NTRK fusion protein TPM3-NTRK1 was detected in colon cancer in 1982, over 100 different 5 0 fusion partners have been identified in more than 20 types of human tumors 8,10,12,53,54 . Among three NTRK isoforms, NTRK1 and NTRK3 fusions are widely distributed in a series of different cancer types, while NTRK2 fusions are mainly detected in central nervous system (CNS) tumors 54e57 . ...
... However, the xDFG mutations stabilize the kinases in DFG-out inactive conformation, thus sensitizing the binding of type II TRK inhibitors 28,29 . Some multi-targeted type II kinase inhibitors, e.g., cabozantinib (5), altiratinib (6), foretinib (7) and ponatinib (8), preferentially bind to TRK xDFG mutations and exhibit strong in vitro and in vivo inhibitory activities (Fig. 7). Cabozantinib, a multi-kinase inhibitor for hepatocyte growth factor receptor (c-Met), vascular endothelial growth factor receptor 2 (VEGFR2), and rearranged during transfection (RET) 89 , displays strong biochemical and cellular inhibitory activities against TRKA G667C and Ba/F3-TPM3-NTRK1 cells with IC 50 values of 1 and 99 nmol/L, respectively. ...
Neurotrophic receptor kinase (NTRK) fusions are actionable oncogenic drivers of multiple pediatric and adult solid tumors, and tropomyosin receptor kinase (TRK) has been considered as an attractive therapeutic target for “pan-cancer” harboring these fusions. Currently, two generations TRK inhibitors have been developed. The representative second-generation inhibitors selitrectinib and repotrectinib were designed to overcome clinic acquired resistance of the first-generation inhibitors larotrectinib or entrectinib resulted from solvent-front and gatekeeper on-target mutations. However, xDFG (TRKAG667C/A/S, homologous TRKCG696C/A/S) and some double mutations still confer resistance to selitrectinib and repotrectinib, and overcoming these resistances represents a major unmet clinical need. In this review, we summarize the acquired resistance mechanism of the first- and second-generation TRK inhibitors, and firstly put forward the emerging selective type II TRK inhibitors to overcome xDFG mutations mediated resistance. Additionally, we concluded our perspectives on new challenges and future directions in this field.
... The tyrosine kinase receptor TrkA, the high-affinity receptor for Nerve Growth Factor (NGF), is essential for both the survival and differentiation of neural cells. TrkA, encoded by the NTRK1 gene, was first discovered as a fusion oncogene in colon cancer by Martin-Zanca et al. [1]. Subsequently, this oncogene was detected in other cancers, such as human breast tumor cells and papillary thyroid carcinoma [2,3]. ...
... Here, we discuss the therapeutic potential of these 2 types of compounds for the treatment of cancer in a curative or palliative way. (1,2). First are molecules that block the NGF/TrkA association (1). ...
... Tanezumab is a monoclonal antibody that binds NGF. Peptide A2 and BVNP-0197 also bind NGF but do not (1,2). First are molecules that block the NGF/TrkA association (1). ...
Simple Summary
NGF was the first growth factor discovered by Rita Levi Montalcini in 1950. TrkA, its high affinity receptor, is an oncogene that is overexpressed in many cancers. However, targeted therapies against TrkA, in particular kinase inhibitors, have not yet demonstrated efficacy in the context of overexpression. In this review, after describing the state-of-the-art TrkA-targeted therapies, we will elicit the failures of these therapies by focusing on non-genomic resistance.
Abstract
Larotrectinib and Entrectinib are specific pan-Trk tyrosine kinase inhibitors (TKIs) approved by the Food and Drug Administration (FDA) in 2018 for cancers with an NTRK fusion. Despite initial enthusiasm for these compounds, the French agency (HAS) recently reported their lack of efficacy. In addition, primary and secondary resistance to these TKIs has been observed in the absence of other mutations in cancers with an NTRK fusion. Furthermore, when TrkA is overexpressed, it promotes ligand-independent activation, bypassing the TKI. All of these clinical and experimental observations show that genetics does not explain all therapeutic failures. It is therefore necessary to explore new hypotheses to explain these failures. This review summarizes the current status of therapeutic strategies with TrkA inhibitors, focusing on the mechanisms potentially involved in these failures and more specifically on the role of TrkA.
... The tropomyosin receptor kinase (TRK) receptors, encoded by neurotrophic tyrosine receptor kinase (NTRK) genes (8)(9)(10), belong to the family of integral membrane tyrosine kinases that regulates cell differentiation and survival predominantly in the nervous system (11,12). There are three members in the TRK family: TRKA (encoded by NTRK1), TRKB(NTRK2), and TRKC(NTRK3) (8,13,14). ...
... The tropomyosin receptor kinase (TRK) receptors, encoded by neurotrophic tyrosine receptor kinase (NTRK) genes (8)(9)(10), belong to the family of integral membrane tyrosine kinases that regulates cell differentiation and survival predominantly in the nervous system (11,12). There are three members in the TRK family: TRKA (encoded by NTRK1), TRKB(NTRK2), and TRKC(NTRK3) (8,13,14). Native TRK receptors can be activated by its specific ligands (13)(14)(15)(16) and dimerize to trigger downstream signaling cascades (17). The dimerization of native TRKs leads to the autophosphorylation and subsequent activation of downstream signaling pathways, mainly including RAS(rat sarcoma)-MAPK(mitogen activated protein kinase), phosphoinositide 3-kinase, and protein kinase C (PKC) pathways (18). ...
NTRK (neurotrophic tyrosine receptor kinase) gene fusions that encode chimeric proteins exhibiting constitutive activity of tropomyosin receptor kinases (TRK), are oncogenic drivers in multiple cancer types. However, the underlying mechanisms in oncogenesis that involve various N-terminal fusion partners of NTRK fusions remain elusive. Here, we show that NTRK fusion proteins form liquid-like condensates driven by their N-terminal fusion partners. The kinase reactions are accelerated in these condensates where the complexes for downstream signaling activation are also concentrated. Our work demonstrates that the phase separation driven by NTRK fusions is not only critical for TRK activation, but the condensates formed through phase separation serve as organizational hubs for oncogenic signaling.
... Tropomyosin receptor kinase A (TrkA) serves as a high-affinity catalytic receptor for NGF. In its function as a kinase, TrkA orchestrates various NGF effects, including neuronal differentiation, neural proliferation, nociceptor response, the inhibition of programmed cell death, cell metastasis, and tumor progression [20,21]. Researchers have demonstrated that inhibiting NGF or its receptor (TrkA) significantly retards tumor development, reduces pain-related activity, and ameliorated bone damage in sarcoma. ...
Osteosarcoma (OS) therapy presents numerous challenges, due largely to a low survival rate following metastasis onset. Nerve growth factor (NGF) has been implicated in the metastasis and progression of various cancers; however, the mechanism by which NGF promotes metastasis in osteosarcoma has yet to be elucidated. This study investigated the influence of NGF on the migration and metastasis of osteosarcoma patients (88 cases) as well as the underlying molecular mechanisms, based on RNA-sequencing and gene expression data from a public database (TARGET-OS). In osteosarcoma patients, the expression of NGF was significantly higher than that of other growth factors. This observation was confirmed in bone tissue arrays from 91 osteosarcoma patients, in which the expression levels of NGF and matrix metallopeptidase-2 (MMP-2) protein were significantly higher than in normal bone, and strongly correlated with tumor stage. In summary, NGF is positively correlated with MMP-2 in human osteosarcoma tissue and NGF promotes osteosarcoma cell metastasis by upregulating MMP-2 expression. In cellular experiments using human osteosarcoma cells (143B and MG63), NGF upregulated MMP-2 expression and promoted wound healing, cell migration, and cell invasion. Pre-treatment with MEK and ERK inhibitors or siRNA attenuated the effects of NGF on cell migration and invasion. Stimulation with NGF was shown to promote phosphorylation along the MEK/ERK signaling pathway and decrease the expression of microRNA-92a-1-5p (miR-92a-1-5p). In in vivo experiments involving an orthotopic mouse model, the overexpression of NGF enhanced the effects of NGF on lung metastasis. Note that larotrectinib (a tropomyosin kinase receptor) strongly inhibited the effect of NGF on lung metastasis. In conclusion, it appears that NGF promotes MMP-2-dependent cell migration by inhibiting the effects of miR-92a-1-5p via the MEK/ERK signaling cascade. Larotrectinib emerged as a potential drug for the treatment of NGF-mediated metastasis in osteosarcoma.
... NTRK1 was initially discovered in 1986 as part of a novel tyrosine kinase family isolated from human colon carcinoma cells (Martin-Zanca et al., 1986, 1989. NTRK1 encodes the TrkA protein, which acts as a signaltransducing receptor for NGF (Kaplan et al., 1991;Klein et al., 1991). ...
Background:
Congenital insensitivity to pain with anhidrosis (CIPA) is an extremely rare autosomal recessive disorder caused by loss-of-function mutations of the NTRK1 gene, affecting the autonomic and sensory nervous system. Clinical manifestation is varied and includes recurrent fever, pain insensitivity, anhidrosis, self-mutilating behavior, and intellectual disability.
Methods:
Clinical and genetic features were assessed in two males and one female with genetically confirmed CIPA using exome or genome sequencing.
Results:
CIPA symptoms including recurrent fever, pain insensitivity, and anhidrosis manifested at the age of 1 year (age range: 0.3-8 years). Two patients exhibited self-mutilation tendencies, intellectual disability, and developmental delay. Four NTRK1 (NM_002529.3) mutations, c.851-33T>A (p.?), c.2020G>T (p.Asp674Tyr), c.2303C>T (p.Pro768Leu), and c.574-156_850+1113del (exons 5-7 del) were identified. Two patients exhibited early onset and severe phenotype, being homozygous for c.851-33T>A (p.?) mutations and compound heterozygous for c.851-33T>A (p.?) and c.2020G>T (p.Asp674Tyr) mutation of NTRK1. The third patient with compound heterozygous mutations of c.2303C>T (p.Pro768Leu) and c.574-156_850+1113del (exons 5-7 del) displayed a late onset and milder clinical manifestation.
Conclusion:
All three patients exhibited variable phenotypes and disease severity. This research enriches our understanding of clinical and genetic aspects of CIPA, highlighting variable phenotypes and disease severity.
... 34 However, its role in hematopoiesis and HSC biology has been less reported. NTRK1 fusions have been implicated in a number of solid tumor malignancies, [35][36][37][38] representing an important therapeutic target. 39 In normal hematopoiesis, NTRK1 is expressed at the highest levels in the common myeloid progenitors and early monocytes, whereas in AML, NTRK1 is overexpressed mainly in core-binding factor AML. 40,41 In RUNX1::RUNX1T1 rearranged AML, BM stromal cells express nerve growth factor, which can bind to TRKA (encoded by the NTRK1 gene), leading to leukemogenesis. ...
The human kinome, which comprises over five hundred kinases, plays a critical role in regulating numerous essential cellular functions. Although the dysregulation of kinases has been observed in various human cancers, the characterization and clinical implications of kinase expressions in myelodysplastic syndrome (MDS) have not been systematically investigated. In this study, we evaluated the kinome expression profiles of 341 adult patients with primary MDS and identified seven kinases (PTK7, KIT, MAST4, NTRK1, PAK6, CAMK1D, and PRKCZ) whose expression levels were highly predictive of compromised patient survival. We then constructed the KInase Stratification Score (KISS) by combining the weighted expressions of the seven kinases, and validated its prognostic significance in two external MDS cohorts. A higher KISS was associated with older age, higher peripheral blood and marrow blast percentages, higher Revised International Prognostic Scoring System (IPSS-R) risks, complex karyotype, and mutations in several adverse-risk genes in MDS, such as ASXL1, EZH2, NPM1, RUNX1, STAG2, and TP53. Multivariate analysis confirmed that a higher KISS was an independent unfavorable risk factor in MDS. Mechanistically, the KISS-high patients were enriched for genesets associated with hematopoietic and leukemic stem cell signatures. By investigating the Genomics of Drug Sensitivity in Cancer (GDSC) database, we identified axitinib and taselisib as candidate compounds that could potentially target the KISS-high myeloblasts. Altogether, our findings suggest that KISS holds the potential to improve the current prognostic scheme of MDS and inform novel therapeutic opportunities.
... Interestingly, the study by Kinnunen et al. employed proximity-labeled mass spectrometry to establish a stable, reliable association of the ETV6-NTRK3 fusion with several key signaling pathways, including ERBB, IRS-1, and JAK/STAT (Kinnunen et al., 2023). As another of the more common and first reported NTRK fusion mutations, TPM3-NTRK1 was initially identified in colorectal cancer (CRC) samples, and subsequent studies have confirmed that chromosomal rearrangements in this manner make patients with CRC highly sensitive to TRKA inhibitors (Martin-Zanca et al., 1986;Ardini et al., 2014;Créancier et al., 2015). Other fusion types, such as SQSTM1-NTRK1, although carried by only one patient with THCA in our study, a recent case report demonstrated that patients carrying SQSTM1-NTRK1 had a 51% reduction in tumor burden after 18 months of treatment with larotrectinib, and this impressive efficacy continued (Bargas et al., 2022). ...
Introduction: The discovery of neurotrophic tyrosine receptor kinase (NTRK) gene fusions has facilitated the development of precision oncology. Two first-generation NTRK inhibitors (larotrectinib and entrectinib) are currently approved for the treatment of patients with solid tumors harboring NTRK gene fusions. Nevertheless, comprehensive NTRK profiling at the pan-cancer genomic level and real-world studies pertaining to the adverse events of NTRK inhibitors are lacking.
Methods: We characterize the genome of NTRK at the pan-cancer level through multi-omics databases such as The Cancer Genome Atlas (TCGA). Through the FDA Adverse Event Reporting System (FAERS) database, we collect reports of entrectinib and larotrectinib-induced adverse events and perform a pharmacovigilance analysis using various disproportionality methods.
Results: NTRK1/2/3 expression is lower in most tumor tissues, while they have higher methylation levels. NTRK gene expression has prognostic value in some cancer types, such as breast invasive carcinoma (BRCA). The cancer type with highest NTRK alteration frequency is skin cutaneous melanoma (SKCM) (31.98%). Thyroid carcinoma (THCA) has the largest number of NTRK fusion cases, and the most common fusion pair is ETV6-NTRK3. Adverse drug events (ADEs) obtained from the FAERS database for larotrectinib and entrectinib are 524 and 563, respectively. At the System Organ Class (SOC) level, both drugs have positive signal value for “nervous system disorder”. Other positive signals for entrectinib include “cardiac disorders”, “metabolism and nutrition disorders”, while for larotrectinib, it is “hepatobiliary disorders”. The unexpected signals are also listed in detail. ADEs of the two NTRK inhibitors mainly occur in the first month. The median onset time of ADEs for entrectinib and larotrectinib was 16 days (interquartile range [IQR] 6–86.5) and 44 days ([IQR] 7–136), respectively.
Conclusion: Our analysis provides a broad molecular view of the NTRK family. The real-world adverse drug event analysis of entrectinib and larotrectinib contributes to more refined medication management.
... Oncogenic fusions between the C-terminal kinase domain with the N-terminal fusion partner of the NTRK genes have been identified in high prevalence in rare subtypes of pediatric and adult tumors and are implicated in a small percentage of common adult patient cancers. The first TRK fusion protein was originally described more than 35 years ago in colorectal cancer [9]. In subsequent years, few other studies on NTRK gene alterations in colorectal carcinomas have been reported [10,11]. ...
Objectives
Actionable, solid tumor activating neurotrophic receptor tyrosine kinase (NTRK) fusions are best detected via nucleic acid-based assays, while Pan-TRK immunohistochemistry (IHC) serves as a reasonable screening modality. We describe a practical and cost-effective approach to validate pan-TRK and discuss challenges that may be encountered.
Methods
Pan-TRK Clone EPR17341 was validated in accordance with the 2014 consensus statements set forth by the College of American Pathologists. Confirmation of IHC results were guided by the European Society of Medical Oncology recommendations for standard methods to detect NTRK fusions.
Results
Within 36 samples, ETV6-NTRK3 (n = 8) and TPM4-NTRK3 (n = 1) fusions were confirmed. ETV6-NTRK3 fusion positive cases revealed cytoplasmic and nuclear staining. A TPM4-NTRK3 fusion positive high grade malignant peripheral nerve sheath tumor revealed diffuse cytoplasmic staining. A high grade ovarian serous carcinoma revealed focal punctate staining and revealed a non-actionable NTRK1 truncation at intron 2. Diffuse cytoplasmic staining was observed in a case of fusion-negative polymorphous adenocarcinoma. Wild-type expression of TRK in pulmonary meningothelial-like nodules was discovered following a false-positive IHC interpretation.
Conclusion
Pan-TRK IHC shows some utility as a diagnostic and surrogate marker for NTRK screening however, physiologic or non-specific expression may lead to false-positive results.
... A family of genes called NTRK1, NTRK2, and NTRK3 encode a protein called tropomyosin receptor kinases (TRK). Mutation in NTRK genes results in TRK fusion proteins that lead to tissue-independent oncogenic transformation [33][34][35]. TRK fusion proteins are found in more than 20 different tumor types. As a result, a phase II basket trial was conducted to evaluate the therapeutic effect of larotrectinib, a TRK inhibitor, in 55 patients diagnosed with 12 different cancer types. ...
Simple Summary
This paper provides a review of statistical methods for tumor-agnostic clinical trials. In particular, the review focuses on basket trials and provides methodological insights into various Bayesian approaches. The key concept of borrowing information through Bayesian hierarchical models is emphasized, and some novel trial designs are introduced. The review is expected to provide oncology and biostatistics researchers with more exposure to powerful Bayesian methods for the design and analysis of tumor-agnostic clinical trials.
Abstract
Basket trials allow simultaneous evaluation of a single therapy across multiple cancer types or subtypes of the same cancer. Since the same treatment is tested across all baskets, it may be desirable to borrow information across them to improve the statistical precision and power in estimating and detecting the treatment effects in different baskets. We review recent developments in Bayesian methods for the design and analysis of basket trials, focusing on the mechanism of information borrowing. We explain the common components of these methods, such as a prior model for the treatment effects that embodies an assumption of exchangeability. We also discuss the distinct features of these methods that lead to different degrees of borrowing. Through simulation studies, we demonstrate the impact of information borrowing on the operating characteristics of these methods and discuss its broader implications for drug development. Examples of basket trials are presented in both phase I and phase II settings.
... The rearrangement between tropomyosin 3 (TPM3) and NTRK1 in colorectal cancer was the first detected NTRK fusion (8). Afterward, NTRK fusions were found with several partners in a wide diversity of cancer typologies: among the fusions involving NTRK1 are known the fusions with ROS Proto-Oncogene 1, Receptor Tyrosine Kinase (ROS1) and Lamin A/C (LMNA), involved in spitzoid neoplasms and in soft tissue sarcomas (STS), respectively (9). ...
The family of the neurotrophic tyrosine kinase receptor ( NTRK ) gene encodes for members of the tropomyosin receptor kinase (TRK) family. Rearrangements involving NTRK1/2/3 are rare oncogenic factors reported with variable frequencies in an extensive range of cancers in pediatrics and adult populations, although they are more common in the former than in the latter. The alterations in these genes are causative of the constitutive activation of TRKs that drive carcinogenesis. In 2017, first-generation TRK inhibitor (TRKi) larotrectinib was granted accelerated approval from the FDA, having demonstrated histologic-agnostic activity against NTRK s fusions tumors. Since this new era has begun, resistance to first-generation TRKi has been described and has opened the development of second-generation molecules, such as selitrectinib and repotrectinib. In this review, we provide a brief overview of the studies on NTRK alterations found in pediatric central nervous system tumors and first and second-generation TRKi useful in clinical practice.
... Генетические аберрации с вовлечением генов семейства NTRK встречаются в 0,34-2,2% случаев всех солидных ЗНО, при этом опухоли с перестройками указанных генов не имеют общих характерных клинических или гистологических особенностей [1][2][3]. Перестройки генов NTRK впервые были обнаружены при карциноме толстой кишки в 1982 г. [8], а химерный ген ETV6::NTRK3 был описан при инфантильной фибросаркоме еще в 1998 г. [9]. В последние годы благодаря широкому использованию технологии высокопроизводительного секвенирования спектр опухолей с перестройками генов NTRK1/2/3 постепенно расширялся. ...
Somatic translocations involving the NTRK genes occur in 0.34–2.2% of all malignant neoplasms in children. TRK inhibitors whose efficacy has been demonstrated in prospective clinical studies expand treatment options for patients with solid tumors harboring NTRK gene rearrangements. The aim of our study was to summarize the first Russian experience with the use of the TRK inhibitor entrectinib in patients with extracranial NTRK fusion-positive solid tumors included in the compassionate use program. This study was approved by the Independent Ethics Committee and the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The study included 8 patients who had been treated at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology and the N.N. Blokhin National Medical Research Center of Oncology. The main criteria for inclusion in the compassionate use program were a confirmed rearrangement of either NTRK1/2/3 genes in a solid tumor in patients with unresectable disease for whom no effective standard systemic therapy was available, progressive or recurrent disease during therapy prescribed according to the established diagnosis, risk group and risk stratification criteria, and the infeasibility of non-mutilating radical surgery. The median age at diagnosis was 4.3 months (range 1.2–83.6). The male to female ratio was 1:1. The primary site distribution was as follows: head and neck (n = 6; 75%), chest wall (n = 1; 12.5%), pelvis (n = 1; 12.5%). None of the patients had regional lymph node involvement or distant metastases at diagnosis. The distribution by histology (according to histopathology reports) was as follows: infantile fibrosarcoma (n = 4; 50%), undifferentiated round cell sarcoma, low-grade (n = 1; 12.5%), undifferentiated spindle cell sarcoma, high-grade (n = 1; 12.5%), NTRK-rearranged spindle cell sarcoma, low-grade (n = 1; 12.5%), spindle cell tumor associated with an NTRK rearrangement (n = 1; 12.5%). Immunohistochemistry (IHC) with a pan-Trk monoclonal antibody was performed in 7/8 (87.5%) patients. Pan-Trk IHC was positive in 4/7 (57%) patients. Rearrangements in the NTRK1 and NTRK3 genes were confirmed in all the patients. The final methods used for the detection of fusion transcripts were as follows: reverse transcription polymerase chain reaction (n = 4; 50%) and RNA-based next-generation sequencing (n = 4; 50%). NTRK1 and NTRK3 gene translocations were detected in 3/8 (37.5%) and 5/8 (62.5%) patients, respectively. The following fusion transcripts were identified: ETV6::NTRK3 (n = 4), DIP2C::NTRK3 (n = 1), TPR::NTRK1 (n = 1), TPM3::NTRK1 (n = 1), MYH10::NTRK1 (n = 1). One (12.5%) patient received entrectinib as first-line therapy, other patients (7/8, 87.5%) received entrectinib as secondor subsequent-line therapy. Three (37.5%) patients had undergone surgery before treatment with entrectinib: 2 had R2 resection, 1 had R0/R1 resection (resection margins were not evaluated). None of the patients received radiation therapy. The median duration of entrectinib therapy at the time of analysis was 11.8 months (range 2.3–20.1). Delayed surgery was performed in 2/8 patients; according to the histopathology reports, they achieved grade IV pathomorphosis. Three patients experienced adverse events during treatment with entrectinib. The median time to adverse events was 0.23 months (range 0.2–7.96). Three patients required temporary interruption in treatment to relieve symptoms, a subsequent dose reduction by one dose level was necessary when resuming therapy in two patients. The median follow-up since diagnosis was 19.5 months (range 14.9–75.0). All the patients included in our analysis were alive, three of them had no radiologic evidence of disease. Fifty percent of the patients completed targeted therapy, another 50% of the patients continued treatment with entrectinib. Complete and very good partial response was achieved in 3/8 and 2/8 patients, respectively. Partial response, minor partial response and stable disease were observed in one patient each. These results indicate high efficacy and safety of entrectinib in pediatric patients with extracranial NTRK fusion-positive solid tumors. Further studies are needed to determine the therapeutic potential of TRK inhibitors in the treatment of different solid malignant neoplasms in children and to assess long-term treatment results.
... TPM3 is frequently involved in gene rearrangements leading to fusion with the neurotrophic tyrosine kinase receptor type 1 (NTRK1) gene, which then acts as an oncogene [50,51]. The "TPM3-TRK" fusion oncogene is the result of an intra-chromosomal rearrangement that results in the fusion of the TPM3 gene with sequences encoding the transmembrane and intracellular domains of the transmembrane tyrosine kinase known as tropomyosin receptor kinase (TRK) [52,53]. Similar studies have reported that anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase. ...
Cancer is one of the most difficult diseases for human beings to overcome. Its development is closely related to a variety of factors, and its specific mechanisms have been a hot research topic in the field of scientific research. The tropomyosin family (Tpm) is a group of proteins closely related to the cytoskeleton and actin, and recent studies have shown that they play an important role in various cancers, participating in a variety of biological activities, including cell proliferation, invasion, and migration, and have been used as biomarkers for various cancers. The purpose of this review is to explore the research progress of the Tpm family in tumorigenesis development, focusing on the molecular pathways associated with them and their relevant activities involved in tumors. PubMed and Web of Science databases were searched for relevant studies on the role of Tpms in tumorigenesis and development and the activities of Tpms involved in tumors. Data from the literature suggest that the Tpm family is involved in tumor cell proliferation and growth, tumor cell invasion and migration, tumor angiogenesis, tumor cell apoptosis, and immune infiltration of the tumor microenvironment, among other correlations. It can be used as a potential biomarker for early diagnosis, follow-up, and therapeutic response of some tumors. The Tpm family is involved in cancer in a close relationship with miRNAs and LncRNAs. Tpms are involved in tumor tissue invasion and migration as a key link. On this basis, TPM is frequently used as a biomarker for various cancers. However, the specific molecular mechanism of its involvement in cancer progression has not been explained clearly, which remains an important direction for future research.
... The protein encoded by the fusion gene can bind to TRK and activate the downstream PI3K and MAPK pathways, resulting in tumor growth, proliferation, and differentiation. NTRK gene fusion was first identified in patients with CRC and then in those with other tumors (Martin-Zanca et al., 1986;Vaishnavi et al., 2015;Amatu et al., 2019;Solomon et al., 2019). Entrectinib, which targets the NTRK fusion gene, has been shown to be highly therapeutic for patients with NTRK. ...
Colorectal cancer (CRC) is one of the most common malignancies, accounting for approximately 10% of global cancer incidence and mortality. Approximately 20% of patients with CRC present metastatic disease (mCRC) at the time of diagnosis. Moreover, up to 50% of patients with localized disease eventually metastasize. mCRC encompasses a complex cascade of reactions involving multiple factors and processes, leading to a diverse array of molecular mechanisms. Improved comprehension of the pathways underlying cancer cell development and proliferation, coupled with the accessibility of relevant targeted agents, has propelled advancements in CRC treatment, ultimately leading to enhanced survival rates. Mutations in various pathways and location of the primary tumor in CRC influences the efficacy of targeted agents. This review summarizes available targeted agents for different CRC pathways, with a focus on recent advances in anti-angiogenic and anti-epidermal growth factor receptor agents, BRAF mutations, and human epidermal growth factor receptor 2-associated targeted agents.
... The neurotrophic receptor tyrosine kinase (NTRK) genes, including NTRK1, NTRK2 and NTRK3, are key regulators of neuronal and embryonic development. NTRK rearrangements were shown to be able to drive oncogenesis, independently of histology [170,171]. Indeed, NTRK fusions were detected in several type of solid tumors, such us, lung, breast, pancreatic, colon and thyroid [172]. On the basis of a combined analysis of three clinical trials, NCT02122913, NCT02637687 and NCT02576431, which included cancer patients with fusion in one of the three known NTRK genes, larotrectinib was the first FDA-approved molecule in November 2018 for adult and paediatric patients with NTRK fusions solid tumours [173]. ...
Tissue-based biopsy is the present main tool to explore the molecular landscape of cancer, but it also has many limits to be frequently executed, being too invasive with the risk of side effects. These limits and the ability of cancer to constantly evolve its genomic profile, have recently led to the need of a less invasive and more accurate alternative, such as liquid biopsy. By searching Circulating Tumor Cells and residues of their nucleic acids or other tumor products in body fluids, especially in blood, but also in urine, stools and saliva, liquid biopsy is becoming the future of clinical oncology. Despite the current lack of a standardization for its workflows, that makes it hard to be reproduced, liquid biopsy has already obtained promising results for cancer screening, diagnosis, prognosis, and risk of recurrence.
Through a more accessible molecular profiling of tumors, it could become easier to identify biomarkers predictive of response to treatment, such as EGFR mutations in non-small cell lung cancer and KRAS mutations in colorectal cancer, or Microsatellite Instability and Mismatch Repair as predictive markers of pembrolizumab response.
By monitoring circulating tumor DNA in longitudinal repeated sampling of blood we could also predict Minimal Residual Disease and the risk of recurrence in already radically resected patients.
In this review we will discuss about the current knowledge of limitations and strengths of the different forms of liquid biopsies for its inclusion in normal cancer management, with a brief nod to their newest biomarkers and its future implications.
... The three TRKA/B/C members of the receptor tyrosine kinases (TRKs), which are responsible for the growth and functioning of neuronal tissues, are encoded by the NTRK1/2/3 genes [104]. Chen group developed a of potent and selective TRKA degraders 55 & 56 in 2020 by linking a pan-TRK inhibitor, GNF-8625, to a CRBN ligand, thalidomide [105]. . ...
The technology known asPROTACs (PROteolysisTArgeting Chimeras) is a method of protein degradation. Utilising bifunctional small molecules, the ubiquitin-proteosome system (UPS) is used to induce the ubiquitination and degradation of target proteins. In addition to being novel chemical knockdown agents for biological studies that are catalytic, reversible, and rapid, PROTACs used in the treatment for disorders like cancer, immunological disorders, viral diseases, and neurological disorders. The protein degradation field has advanced quickly over the last two years, with a significant rise in research articles on the subject as well as a quick rise in smallmolecule degraders that are currently in or will soon enter the clinical stage. Other new degrading technologies, in addition to PROTAC and molecular glue technology, are also emerging rapidly. In this review article, we mainly focuses on various PROTAC molecules designed with special emphasis on targeted cellular pathways for different diseases i.e., cancer, Viral diseases Immune disorders, Neurodegenerative diseases, etc. We discussed about new technologies based on PROTACs such as Antibody PROTAC, Aptamers, Dual target, Folate caged, TF PROTAC, etc. Also, we listed out the PROTACs which are in clinical trials.
... The initial discovery of nerve growth factor (NGF) [1] paved the way for the identification of homologue proteins including brain-derived neurotrophic factor (BDNF) [2], neurotrophin (NT)-3 [3] and NT-4 [4]. The first tropomyosin receptor kinase (Trk) was originally discovered as a receptor tyrosine kinase with transforming growth activity [5]. It was later on demonstrated that neurotrophins bind to the cognate Trk family of receptors where NGF preferentially binds to TrkA [6], BDNF and NT-4 binds to TrkB [7] and NT-3 binds to TrkC [8]. ...
The introduction of anti-amyloid monoclonal antibodies against Alzheimer’s disease (AD) is of high importance. However, even though treated patients show very little amyloid pathology, there is only a modest effect on the rate of cognitive decline. Although this effect possibly can increase over time, there is still a need for alternative treatments that will improve the cognitive function in patients with AD. Therefore, the purpose of this study was to characterize the triazinetrione ACD856, a novel pan-Trk positive allosteric modulator, in multiple models to address its neuroprotective and potential disease modifying effects. The pharmacological effect of ACD856 was tested in recombinant cell lines, primary cortical neurons or animals. We demonstrate that ACD856 enhanced NGF-induced neurite outgrowth, increased the levels of the pre-synaptic protein SNAP25 in PC12 cells and increased the degree of phosphorylated TrkB in SH-SY5Y cells. In primary cortical neurons, ACD856 led to increased levels of phospho-ERK1/2, showed neuroprotective effect against amyloid-beta or energy-deprivation induced neurotoxicity, and increased the levels of brain derived neurotrophic factor (BDNF). Consequently, administration of ACD856 resulted in a significant increase of BDNF in the brains of 21-months old mice. Furthermore, repeated administration of ACD856 resulted in a sustained anti-depressant effect which lasted up to seven days, suggesting effects that go beyond merely symptomatic effects. In conclusion, the results confirm ACD856 as a cognitive enhancer, but more importantly, they provide substantial in vitro and in vivo evidence of neuroprotective and long-term effects that contribute to neurotrophic support and increased neuroplasticity. Presumably, the described effects of ACD856 may improve cognition, increase resilience, and promote neurorestorative processes, thereby leading to a healthier brain in patients with AD.
... In conclusion, the results confirm ACD856 as a cognitive enhancer, but more importantly, they provide substantial in vitro and in vivo evidence of neuroprotective and longterm effects that contribute to neurotrophic support and increased neuroplasticity. Presumably, the described effects of ACD856 may improve cognition, increase resilience, and promote neurorestorative processes, thereby leading to a healthier brain in patients with AD. kinase with transforming growth activity [5]. It was later demonstrated that neurotrophins bind to the cognate Trk family of receptors where NGF preferentially binds to TrkA [6], BDNF and NT-4 bind to TrkB [7], and NT-3 binds to TrkC [8]. ...
The introduction of anti-amyloid monoclonal antibodies against Alzheimer’s disease (AD) is of high importance. However, even though treated patients show very little amyloid pathology, there is only a modest effect on the rate of cognitive decline. Although this effect can possibly increase over time, there is still a need for alternative treatments that will improve cognitive function in patients with AD. Therefore, the purpose of this study was to characterize the triazinetrione ACD856, a novel pan-Trk positive allosteric modulator, in multiple models to address its neuroprotective and potential disease-modifying effects. The pharmacological effect of ACD856 was tested in recombinant cell lines, primary cortical neurons, or animals. We demonstrate that ACD856 enhanced NGF-induced neurite outgrowth, increased the levels of the pre-synaptic protein SNAP25 in PC12 cells, and increased the degree of phosphorylated TrkB in SH-SY5Y cells. In primary cortical neurons, ACD856 led to increased levels of phospho-ERK1/2, showed a neuroprotective effect against amyloid-beta or energy-deprivation-induced neurotoxicity, and increased the levels of brain-derived neurotrophic factor (BDNF). Consequently, administration of ACD856 resulted in a significant increase in BDNF in the brains of 21 months old mice. Furthermore, repeated administration of ACD856 resulted in a sustained anti-depressant effect, which lasted up to seven days, suggesting effects that go beyond merely symptomatic effects. In conclusion, the results confirm ACD856 as a cognitive enhancer, but more importantly, they provide substantial in vitro and in vivo evidence of neuroprotective and long-term effects that contribute to neurotrophic support and increased neuroplasticity. Presumably, the described effects of ACD856 may improve cognition, increase resilience, and promote neurorestorative processes, thereby leading to a healthier brain in patients with AD.
... Trks are a family of high-affinity neurotrophin receptors belonging to receptor tyrosine kinases. Trks proteins regulate neuronal survival and differentiation 1,2 , and are involved in a variety of diseases, including cancers and neurodegenerative disorders, which makes them prospective drug targets 3,4 . The Human Trk family includes three members: TrkA, TrkB, and TrkC, each specific to its own neurotrophin molecule: NGF, BDNF, and NT3 5 . ...
Neurotrophin receptors of the Trk family are involved in the regulation of brain development and neuroplasticity, and therefore can serve as targets for anti-cancer and stroke-recovery drugs, antidepressants, and many others. The structures of Trk protein domains in various states upon activation need to be elucidated to allow rational drug design. However, little is known about the conformations of the transmembrane and juxtamembrane domains of Trk receptors. In the present study, we employed NMR spectroscopy to solve the structure of the TrkB dimeric transmembrane domain in the lipid environment. We verified the structure using mutagenesis and confirmed that the conformation corresponds to the active state of the receptor. Subsequent study of TrkB interaction with the antidepressant drug fluoxetine, and the antipsychotic drug chlorpromazine, provided a clear self-consistent model, describing the mechanism by which fluoxetine activates the receptor by binding to its transmembrane domain.
... Neurotrophic tyrosine receptor kinase (NTRK) fusions are validated oncogenic drivers of various adult and pediatric tumor types, including NTRK1, NTRK2, and NTRK3, which encode the TRK proteins TRKA, TRKB, and TRKC, respectively (3). Since the initial discovery in colorectal carcinoma (4), NTRK fusions have been identified in 17 unique cancer types, including thyroid cancer (5). NTRK fusions are found at high frequencies(>90%) in rare cancer types (secretory carcinoma, secretory breast carcinoma, infantile fibrosarcoma, and cellular or mixed congenital mesoblastic nephroma), moderate frequencies (5%-25%) in some cancers (papillary thyroid cancer, spitzoid neoplasm, and gastrointestinal stromal tumor) and lower frequencies(<5%) in other common tumors (lung cancer, breast cancer, colorectal cancer, pancreatic cancers, melanoma, and other solid or hematologic cancers) (5). ...
NTRK fusions are validated oncogenic drivers of various adult and pediatric tumor types, including thyroid cancer, and serve as a therapeutic target. Recently, tropomyosin receptor kinase (TRK) inhibitors, such as entrectinib and larotrectinib, display promising therapeutic efficacy in NTRK -positive solid tumors. Although some NTRK fusion partners have been identified in thyroid cancer, the spectrum of NTRK fusion is not fully characterized. In this study, a dual NTRK3 fusion was identified by targeted RNA-Seq in a 47-year-old female patient with papillary thyroid carcinoma. The patient harbors a novel in-frame fusion between NTRK3 exon 13 and AJUBA exon 2, co-existing with a known in-frame fusion between ETV6 exon 4 and NTRK3 exon 14. The dual NTRK3 fusion was validated by Sanger sequencing and fluorescence in situ hybridization (FISH) but lack TRK protein expression as defined by pan-TRK immunohistochemistry (IHC). We supposed the pan-TRK IHC result to be falsely negative. In conclusion, we present the first case of a novel NTRK3-AJUBA fusion co-existing with a known ETV6-NTRK3 fusion in thyroid cancer. These findings extend the spectrum of translocation partners in NTRK3 fusion, and the effect of dual NTRK3 fusion on TRK inhibitor therapy and prognosis needs long-term follow-up.
... NTRK receptors signal through the JAK/STAT, PI3K/AKT, and MEK/ERK pathways to promote cell proliferation, differentiation, and survival [39]. Although numerous studies have investigated the key roles of these receptors in the development and function of the central and peripheral nervous system [40], alterations in NTRK genes have been observed in patients with colon [41], thyroid [42,43], lung [44], glial [45], and breast [46] cancers. These alterations occur at relatively low frequencies (<1%) among patients with each of these types of tumors, but NTRK-driven cancers affect numerous patients, making them key therapeutic targets [47][48][49]. ...
Background: Kidney transplantation is a lifesaving option of selected patients with end-stage kidney disease (ESKD). Urothelial carcinoma (UC) is the most common de novo cancer after kidney transplantation in Taiwan. UC has the characteristics of high mutational burden and elevated degree of molecular heterogeneity compared with other solid tumors. However, there are limited research exploring the genomic alterations in UC after kidney transplantation.
Methods: In this study, we performed whole exome sequencing (WES) to compare the genetic alterations between UC developed after kidney transplantation (UCKT) and UC from hemodialysis patients (UCHD). After mapping and variant calling, a total of 18,733 and 11,093 mutations were identified from UCKT and UCHD patients, respectively. We first excluded known SNPs and then retained genes that were annotated in Cosmic, Intogen, and TCGA bladder databases for onco-driver genes. Seventeen UCKT unique genes with recurrent SNPs in more than two patients were subjected for further analysis. IPA pathway analysis was used to explore the interconnections among these genes.
Results: 17 novel mutations of BTK, CARD11, ELL, FNBP1, GNAQ, HOXD13, IKZF1, MAX, MLLT10, NTRK3, PAX5, SEPTIN6, SEPTIN9, SH3GL1, SLC34A2, TAL1 , and TRAF7 were identified UCKT groups, and none of the genes had been reported in the genomes of patients with UC. Among the affected genes, GNAQ, IKZF1, and NTRK3 were potentially involved in the signaling network of UCKT.
Conclusion : Our findings provide information for understanding the mutational landscape of UC developed after kidney transplantation, and a gene list that may be of great importance in related molecular mechanisms. Genetic analysis in malignancy after transplantation may help to identify high risk patients in post-transplant care and also illuminate a fundamental aspect of the molecular pathogenesis of post-transplantation UC.
... The tropomyosin receptor kinase (TRK) receptor family comprises three members: TRKA, TRKB, and TRKC that are encoded by the NTRK1, NTRK2, and NTRK3 genes, respectively, which plays an important role in regulating cell differentiation, proliferation, pain, and survival (Pulciani et al., 1982;Martin-Zanca et al., 1986;Klein et al., 1989). TRKs are tyrosine kinases receptors and their main implication is the development and function of neuronal tissues (Kargbo, 2020). ...
Proteolysis targeting chimeras (PROTACs) technology can realize the development of drugs for non-druggable targets that are difficult to achieve with traditional small molecules, and therefore has attracted extensive attention from both academia and industry. Up to now, there are more than 600 known E3 ubiquitin ligases with different structures and functions, but only a few have developed corresponding E3 ubiquitin ligase ligands, and the ligands used to design PROTAC molecules are limited to a few types such as VHL (Von-Hippel-Lindau), CRBN (Cereblon), MDM2 (Mouse Doubleminute 2 homolog), IAP (Inhibitor of apoptosis proteins), etc. Most of the PROTAC molecules that have entered clinical trials were developed based on CRBN ligands, and only DT2216 was based on VHL ligand. Obviously, the structural optimization of E3 ubiquitin ligase ligands plays an instrumental role in PROTAC technology from bench to bedside. In this review, we review the structure optimization process of E3 ubiquitin ligase ligands currently entering clinical trials on PROTAC molecules, summarize some characteristics of these ligands in terms of druggability, and provide some preliminary insights into their structural optimization. We hope that this review will help medicinal chemists to develop more druggable molecules into clinical studies and to realize the greater therapeutic potential of PROTAC technology.
... In 1986, the TrkA receptor was isolated from a human colon carcinoma [68] and is encoded by the NTRK1 gene [69,70], located on chromosome 1 (1q21-22) [61,71], in the same manner of the NGF gene. Several lines of evidence underline that the binding of NGF to TrkA receptor mediates proliferation, differentiation and survival of both neurons and cancer cells via the activation of PI3K/Akt, Ras/MAPK and PLCγ pathways [10]. ...
Breast cancer represents the most common type of cancer and is the leading cause of death due to cancer among women. Thus, the prevention and early diagnosis of breast cancer is of primary urgency, as well as the development of new treatments able to improve its prognosis. Nerve Growth Factor (NGF) is a neurotrophic factor involved in the regulation of neuronal functions through the binding of the Tropomyosin receptor kinase A (TrkA) and the Nerve Growth Factor receptor or Pan-Neurotrophin Receptor 75 (NGFR/p75NTR). In addition, its precursor (pro-NGF) can extert biological activity by forming a trimeric complex with NGFR/p75NTR and sortilin, or by binding to TrkA receptors with low affinity. Several examples of in vitro and in vivo evidence show that NGF is both synthesized and released by breast cancer cells, and has mitogen, antiapoptotic and angiogenic effects on these cells through the activation of different signaling cascades that involve TrkA and NGFR/p75NTR receptors. Conversely, pro-NGF signaling has been related to breast cancer invasion and metastasis. Other studies suggested that NGF and its receptors could represent a good diagnostic and prognostic tool, as well as promising therapeutic targets for breast cancer. In this paper, we comprehensively summarize and systematically review the current experimental evidence on this topic. INPLASY ID: INPLASY2022100017.
... un punto de inflexión en la quimioterapia anticancerosa y en el descubrimiento de fármacos por varios motivos. en primer lugar, se trata de uno de los primeros antineoplásicos dirigido a una diana específica y distinta del ADn, gracias a los descubrimientos impulsados por mariano barbacid en el campo de los oncogenes y las proteínas quinasas (4). Por otro lado, el descubrimiento del imatinib supuso un avance en el paradigma del descubrimiento de fármacos moderno, ya que se trata de uno de los primeros ejemplos de diseño basado en estructura para el cáncer, es decir, a partir del conocimiento estructural de la diana farmacológica y su interacción con el fármaco. ...
According to World Health Organization (WHO) cancer is one of top non- infectious death causes worldwide. In this context, as such the searching of new potent and safe anticancer drugs is a hot point for pharmacy industry and academic investigation. Despite protein kinases have been one of the most explored anticancer targets, its evolutionary degenerated parents, pseudokinases, have attracted the attention of scientific community during the last decade. Integrin Linked Kinase (ILK) is a member of the human pseudokinome that has been claimed and validated as a prommissing target for neoplastic diseases. The only well-known ILK inhibitor, CPD22, has probed its activity in phenotypic assays, however very few knowledge regarding its mechanism of action at molecular level is available. Using chemoinformatic and molecular modelling techniques we were able to elucidate if this molecule is able to bind to ILK and how. Additionally, our model explains the SAR raised from the optimization campaign, and SPR experiments have probed, by first time, that this molecule binds to ILK, thus supporting the hypothesis of inhibition by direct binding and the computational model as well.
... 120 Rearrangements occur through fusion of the 3' NTRK1, NTRK2 or NTRK3 sequence with the 5' sequence of a partner gene; partner genes are frequently characterized by oligomerization domains, which contribute to the oncogenic potential of the chimeric protein. [121][122][123] The first to be described and most common fusion partner in adult NTRK-fusion-positive tumours is ETV6, followed by many others (TPM3, TPR, SQSTM1, IRF2BP2 REVIEW -Non-small-cell lung cancer: how to manage ALK-, ROS1-and NTRK-rearranged disease drugsincontext.com perioral distribution and were mostly mild in grade, often requiring no therapeutic intervention. ...
Oncogene addiction in non-small-cell lung cancer (NSCLC) has profound diagnostic and therapeutic implications. ALK, ROS1 and NTRK rearrangements are found in about 2-7%, 1-2% and 0.2% of unselected NSCLC samples, respectively; however, their frequency is markedly higher in younger and never-smoker patients with adenocarcinoma histology. Moreover, ALK, ROS1 and NTRK rearrangements are often mutually exclusive with other known driver alterations in NSCLC. Due to such a low frequency, diagnostic screening with accurate and inexpensive techniques such as immunohistochemistry is useful to identify positive cases; however, confirmation with fluorescent in situ hybridization or next-generation sequencing is often required due to higher specificity. In ALK-rearranged NSCLC, sequential treatment with second-generation and third-generation tyrosine kinase inhibitors leads to long-lasting disease control with most patients surviving beyond 5 years with metastatic disease. In ROS1-rearranged NSCLC, first-line treatment with crizotinib or entrectinib and subsequent treatment with lorlatinib at disease progression leads to similar results in patients with metastatic disease. NTRK1-3 fusions are extremely rare in unselected NSCLC. However, treatment with TRK inhibitors yields high response rates and durable disease control in most patients; diagnostic screening through multigene DNA/RNA-based next-generation sequencing testing is therefore crucial to identify positive cases. This article is part of the Treatment of advanced non-small-cell lung cancer: one size does not fit all Special Issue: https://www.drugsincontext.com/special_issues/treatment-of-advanced-non-small-cell-lung-cancer-one-size-does-not-fit-all/.
... pain-related disorders, [11][12][13] and neurodegenerative diseases. 14,15 The biological action of NGF depends on the cellular context and is elicited through binding and activation of its receptors, namely TrkA (Tropomyosin-Related Kinase receptor type I) [16][17][18][19] and p75 NTR (a member of the Tumor necrosis factor receptor superfamily). [20][21][22][23] TrkA has the highest affinity for NGF, and responds to ligand binding with dimerization and transphosphorylation, leading to the activation of key signaling pathways, such as extracellular signal-regulated kinase (ERK), phospholipase C-γ (PLC-γ) and phosphatidyl-inositol 3 kinase (PI3K). ...
The binding of nerve growth factor (NGF) to the tropomyosin–related kinase A (TrkA) and p75NTR receptors activates a large variety of pathways regulating critical processes as diverse as proliferation, differentiation, membrane potential, synaptic plasticity, and pain. To ascertain the details of TrkA‐p75NTR interaction and cooperation, a plethora of experiments, mostly based on receptor overexpression or downregulation, have been performed. Among the heterogeneous cellular systems used for studying NGF signaling, the PC12 pheochromocytoma‐derived cell line is a widely used model. By means of CRISPR/Cas9 genome editing, we created PC12 cells lacking TrkA, p75NTR, or both. We found that TrkA‐null cells become unresponsive to NGF. Conversely, the absence of p75NTR enhances the phosphorylation of TrkA and its effectors. Using a patch‐clamp, we demonstrated that the individual activation of TrkA and p75NTR by NGF results in antagonizing effects on the membrane potential. These newly developed PC12 cell lines can be used to investigate the specific roles of TrkA and p75NTR in a genetically defined cellular model, thus providing a useful platform for future studies and further gene editing.
... The TrkA receptor was isolated in 1986 from a human colon carcinoma [76] and is encoded by the NTRK1 gene [77,78], located on chromosome 1 (1q21-22) [69,79] in the same manner of the NGF gene. Several data showed that the NGF binding to TrkA receptor mediates proliferation, differentiation and survival of both neurons and cancer cells via activation of PI3K/Akt, Ras/MAPK and PLCγ pathways [10]. ...
Breast cancer represents the most frequent cancer and the leading cause of cancer death among women. Thus, the prevention and early diagnosis of breast cancer appears to be of primary urgency as well as the development of new treatments able to improve its prognosis. Nerve Growth Factor (NGF) is a neurotrophic factor that plays a key role in the regulation of neuronal functions thought the binding to the Tropomyosin receptor kinase A (TrkA) and the Nerve Growth Factor receptor or Pan-Neurotrophin Receptor 75 (NGFR/p75NTR). Also, its precursor (pro-NGF) can extert biological activity by forming a trimeric complex with NGFR/p75NTR and sortilin or by binding to TrkA receptors with low affinity. Both in vitro and in vivo studies showed that NGF is synthesized and released by breast cancer cells and has mitogen, antiapoptotic and angiogenic effects on these cells through the activation of different signaling cascades that involve TrkA and NGFR/p75NTR receptors. Conversely, pro-NGF signaling has been related to breast cancer invasion and metastasis. Other studies suggested that NGF and its receptors could represent a good diagnostic and prognostic tool, as well as promising therapeutic targets for breast cancer. Here, we comprehensively summarize and systematically review the current experimental evidence on this topic.
... During early postnatal period, proBDNF reaches a high concentration, while mBDNF is more dominant in adulthood (Yang et al., 2009(Yang et al., , 2014. mBDNF takes effect by binding with two kinds of plasma membrane receptors, the TrkB receptor (Martin-Zanca et al., 1986) and the p75 neurotrophin receptor (Dechant and Barde, 2002). mBDNF, as a member of the neurotrophin family, has a high affinity (dissociation constant ∼10 11 M) to TrkB receptor (Rodriguez-Tébar and Barde, 1988), which promotes cell survival (Volosin et al., 2006), facilitates long term potentiation (LTP) and increases spine complexity (Zagrebelsky et al., 2005). ...
Brain derived neurotrophic factor (BDNF) has multiple biological functions which are mediated by the activation of two receptors, tropomyosin receptor kinase B (TrkB) receptor and the p75 neurotrophin receptor, involving in physiological and pathological processes throughout life. The diverse presence and activity of BDNF indicate its potential role in the pathogenesis, progression and treatment of both neurological and psychiatric disorders. This review is to provide a comprehensive assessment of the current knowledge and future directions in BDNF-associated research in the central nervous system (CNS), with an emphasis on the physiological and pathological functions of BDNF as well as its potential treatment effects in CNS diseases, including depression, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, multiple sclerosis, and cerebral ischemic stroke.
... NTRK receptors signal through the JAK/STAT, PI3K/AKT, and MEK/ ERK pathways to promote cell proliferation, differentiation, and survival [61]. Although numerous studies have investigated the key roles of these receptors in the development and function of the central and peripheral nervous system [62], alterations in NTRK genes have been observed in patients with colon [63], thyroid [64,65], lung [66], glial [67], and breast [68] cancers. These alterations occur at relatively low frequencies (< 1%) among patients with each of these types of tumors, but NTRKdriven cancers affect numerous patients, making them key therapeutic targets [69][70][71]. ...
Kidney transplantation is a lifesaving option for patients with end-stage kidney disease. In Taiwan, urothelial carcinoma (UC) is the most common de novo cancer after kidney transplantation (KT). UC has a greater degree of molecular heterogeneity than do other solid tumors. Few studies have explored genomic alterations in UC after KT. We performed whole-exome sequencing to compare the genetic alterations in UC developed after kidney transplantation (UCKT) and in UC in patients on hemodialysis (UCHD). After mapping and variant calling, 18,733 and 11,093 variants were identified in patients with UCKT and UCHD, respectively. We excluded known single-nucleotide polymorphisms (SNPs) and retained genes that were annotated in the Catalogue of Somatic Mutations in Cancer (COSMIC), in the Integrative Onco Genomic cancer mutations browser (IntOGen), and in the Cancer Genome Atlas (TCGA) database of genes associated with bladder cancer. A total of 14 UCKT-specific genes with SNPs identified in more than two patients were included in further analyses. The single-base substitution (SBS) profile and signatures showed a relative high T > A pattern compared to COMSIC UC mutations. Ingenuity pathway analysis was used to explore the connections among these genes. GNAQ, IKZF1, and NTRK3 were identified as potentially involved in the signaling network of UCKT. The genetic analysis of posttransplant malignancies may elucidate a fundamental aspect of the molecular pathogenesis of UCKT.
... TRKs are receptor tyrosine kinases encoded by the NTRK1/2/3 genes and contain mainly three members(TRKA/B/C), which are associated with the development and function of neuronal tissues. 470 When the extracellular structural domains of TRKs bind to their corresponding ligands, they will induce dimerization and activation of the intracellular kinase domains of TRKs thereby providing signals to downstream PI3K/AKT, RAF/MEK/ ERK, and phospholipase C gamma(PLCγ). 471 This ultimately leads to constitutive activation of the TRK pathway and promotes cell proliferation, survival, and malignant transformation. ...
PROteolysis TArgeting Chimeras (PROTACs) technology is a new protein-degradation strategy that has emerged in recent years. It uses bifunctional small molecules to induce the ubiquitination and degradation of target proteins through the ubiquitin–proteasome system. PROTACs can not only be used as potential clinical treatments for diseases such as cancer, immune disorders, viral infections, and neurodegenerative diseases, but also provide unique chemical knockdown tools for biological research in a catalytic, reversible, and rapid manner. In 2019, our group published a review article “PROTACs: great opportunities for academia and industry” in the journal, summarizing the representative compounds of PROTACs reported before the end of 2019. In the past 2 years, the entire field of protein degradation has experienced rapid development, including not only a large increase in the number of research papers on protein-degradation technology but also a rapid increase in the number of small-molecule degraders that have entered the clinical and will enter the clinical stage. In addition to PROTAC and molecular glue technology, other new degradation technologies are also developing rapidly. In this article, we mainly summarize and review the representative PROTACs of related targets published in 2020–2021 to present to researchers the exciting developments in the field of protein degradation. The problems that need to be solved in this field will also be briefly introduced.
... TrkA fut le premier membre de la famille des récepteurs à activité tyrosine kinase Trk à être découvert en 1986 (Martin-Zanca et al., 1986). Les auteurs mirent alors en avant l'existence, dans le cancer du côlon humain, d'un oncogène résultant de la fusion des séquences d'une partie intracellulaire d'un récepteur encore inconnu et de la partie extracellulaire de la tropomyosine, qu'ils nommèrent en conséquence trk (tropomyosin receptor kinase). ...
Le laboratoire INSERM U908 a montré le rôle déterminant du facteur de croissance NGF dans l’agressivité du cancer du sein. De précédentes études ont montré que l’inhibition de l’activité de TrkA, le récepteur du NGF, aboutissait à une diminution de la taille des tumeurs in vitro mais aussi dans des modèles pré-cliniques. Néanmoins, ces inhibiteurs ont donné lieu à des essais cliniques décevants. La résistance à ces inhibiteurs est en partie due à l’association de récepteurs membranaires. Plus précisément, mon travail de thèse a permis de démontrer qu’une forme particulière du récepteur CD44 interagit avec TrkA ce qui conduit à une résistance aux traitements. De plus, j’ai également montré l’existence d’une interaction entre TrkA et deux autres récepteurs. Ainsi, j’ai pu déterminer précisément comment ces récepteurs coopèrent afin de développer des inhibiteurs ciblant leur interaction. Ces inhibiteurs pourraient donc s’avérer efficaces pour le traitement de certains cancers du sein. Ma thèse souligne l’importance des complexes de récepteurs dans la plasticité des cellules cancéreuses et leur capacité à s’adapter pour résister aux thérapies ciblées.
... The binding of TrkA by nerve growth factor (NGF) causes activation of the RAS/MAPK pathway, leading to increased cellular proliferation and growth via ERK signaling (7). The oncogenic role of Trk was first identified in colorectal cancer (CRC) in 1986 due to an NTRK1 rearrangement (8), resulting in fusion with other genes, upregulating downstream signaling pathways independent of ligand, and promoting tumor cell proliferation and metastasis. In recent years, NTRK1 rearrangements have been confirmed in multiple cancers by next-generation sequencing, including lung cancer, soft tissue sarcoma, glioma, and malignant melanoma (9)(10)(11)(12)(13). ...
We collected 61 craniopharyngioma (CP) specimens to investigate the expression of TrkA, β-catenin, BRAF gene mutation, and NTRK1 fusion in CP. There were 37 male and 24 female individuals with a median age of 34 years (range, 4–75 years). Histologically, there were 46 cases of adamantinomatous craniopharyngioma (ACP), 14 cases of papillary craniopharyngioma (PCP), and 1 case with a mixed adamantinomatous and papillary pattern. By immunohistochemistry, we found that moderate/high TrkA expression was detected in 47% (28/60) CP and was significantly higher in adult patients (p = 0.018). Interestingly, TrkA is more expressed in “whorled epithelium” cells in ACP, similar to the localization of abnormal β-catenin. The abnormal expression rate of β-catenin was 70% (43/61), and the medium/high cyclin D1 expression rate was 73% (44/60), both of which were significantly higher in ACP than in PCP. Of the CP, 41% (21/51) had a moderate/strong P16-positive signal; 58% (34/59) showed a high Ki-67 expression, and there was a significant correlation between high Ki-67 L.I. and high tumor recurrence (p = 0.021). NTRK1 fusion was not found in CP by fluorescence in situ hybridization (FISH). By PCR, 26% (15/58) CP showed BRAF V600E gene mutation, which mainly occurred in PCP (100%, 14/14) except one case of mixed CP. Moreover, TrkA expression was negatively correlated with Ki-67 index and positively correlated with P16 expression. There was a significantly negative correlation between BRAF V600E mutation and abnormal β-catenin expression. Our results demonstrate for the first time that TrkA expression might occur in CP, especially in adult CP patients, and suggest that cyclin D1 could be used for ACP histological classification in addition to β-catenin and BRAF V600E mutation, while Ki-67 could be used as a marker to predict CP recurrence.
Mutation of thetumor suppressor gene, TP53 (tumor protein 53), occurs in up to 15% of all patients with acute myeloid leukemia (AML) and is enriched within specific clinical subsets, most notably in older adults, and including secondary AML cases arising from preceding myeloproliferative neoplasm (MPN), myelodysplastic syndrome (MDS), patients exposed to prior DNA-damaging, cytotoxic therapies. In all cases, these tumors have remained difficult to effectively treat with conventional therapeutic regimens. Newer approaches fortreatmentofTP53-mutated AML have shifted to interventions that maymodulateTP53 function, target downstream molecular vulnerabilities, target non-p53 dependent molecular pathways, and/or elicit immunogenic responses. This review will describe the basic biology of TP53, the clinical and biological patterns of TP53 within myeloid neoplasms with a focus on elderly AML patients and will summarize newer therapeutic strategies and current clinical trials.
Background:
The tropomyosin receptor kinases (TRKs) are crucial for many cellular functions, such as growth, motility, differentiation, and metabolism. Abnormal TRK signalling contributes to a variety of human disorders, most evidently cancer. Comprehensive genomic stud-ies have found numerous changes in the genes that code for TRKs like MET, HER2/ErbB2, and EGFR, among many others. Precision medicine resistance, relapse occurring because of the pro-tein point mutations, and the existence of multiple molecular feedback loops are significant thera-peutic hurdles to the long-term effectiveness of TRK inhibitors as general therapeutic agents for the treatment of cancer.
Objective:
This review is carried out to highlight the role of tropomyosin receptor kinase in can-cer and the function of TRK inhibitors in the intervention of cancer.
Methods:
Literature research has been accomplished using Google Scholar and databases like ScienceDirect, WOS, PubMed, SciFinder, and Scopus.
Results:
In this review, we provide an overview of the main molecular and functional properties of TRKs and their inhibitors. It also discusses how these advancements have affected the devel-opment and use of novel treatments for malignancies and other conditions caused by activated TRKs. Several therapeutic strategies, including the discovery and development of small-molecule TRK inhibitors belonging to various chemical classes and their activity, as well as selectivity to-wards the receptors, have been discussed in detail.
Conclusion:
This review will help the researchers gain a fundamental understanding of TRKs, how this protein family works, and the ways to create chemical moieties, such as TRK inhibitors, which can serve as tailored therapies for cancer.
Tropomyosin receptor kinase (TRK) A, TRKA, is a specific binding receptor of nerve growth factor (NGF), which plays an essential role in the occurrence and progression of human cancers. TRKA overexpression has been proven to be a powerful carcinogenic driver and has been verified in many tumors. The TRKA receptor kinase domain is over-activated in an NGF-dependent manner, accompanied by activation of downstream signal pathways, such as RAS-MAPK, PI3K-AKT, JAK2-STAT3 pathway, PLC γ pathway, and Hippo pathway, which participate in tumor cell proliferation, invasion, epithelial-mesenchymal transition (EMT), perineural invasion (PNI), drug resistance, and cancer pain. In addition, chimeric oncogenes produced by the fusion of NTRK1 and other genes are also the direct cause of tumorigenesis and cancer development. The newly developed TRK inhibitors can improve symptoms and tumor regression in cancer patients with overexpression of TRKA or NTRK1 fusion gene. With the emergence of drug resistance, next generation of TRK inhibitors can still maintain strong clinical efficacy in the case of TRK kinase domain mutations, and these inhibitors are in clinical trials. This review summarizes the characteristics and research progress of TRKA, focusing on the regulatory role of the TRKA signal pathway in different tumors. In addition, we have summarized the clinical significance of TRKA and the TRK inhibitors. This review may provide a new reference for the study of the mechanism of TRKA in different tumors, and also provide a new perspective for the in-depth understanding of the role of TRKA as a biomarker and therapeutic target in human cancer.
The success of precision oncology—which aims to match the right therapies to the right patients based on molecular status—is predicated on a robust pipeline of molecular targets against which therapies can be developed. Recent advances in genomics and functional genetics have enabled the unbiased discovery of novel molecular targets at scale. We summarize the promise and challenges in integrating genomic and functional genetic landscapes of cancer to establish the next generation of cancer targets.
Fusions involving the Neurotrophic tropomyosin receptor kinase (NTRK) gene family (NTRK1, NTRK2 and NTRK3) are targetable oncogenic alterations that are found in a diverse range of tumours. There is an increasing demand to identify tumours which harbour these fusions to enable treatment with selective tyrosine kinase inhibitors such as larotrectinib and entrectinib. NTRK fusions occur in a wide range of tumours including rare tumours such as infantile fibrosarcoma and secretory carcinomas of the salivary gland and breast, as well as at low frequencies in more common tumours including melanoma, colorectal, thyroid and lung carcinomas. Identifying NTRK fusions is a challenging task given the different genetic mechanisms underlying NTRK fusions, their varying frequency across different tumour types, complicated by other factors such as tissue availability, optimal detection methods, accessibility and costs of testing methods. Pathologists play a key role in navigating through these complexities by determining optimal approaches to NTRK testing which has important therapeutic and prognostic implications. This review provides an overview of tumours harbouring NTRK fusions, the importance of identifying these fusions, available testing methods including advantages and limitations, and generalised and tumour-specific approaches to testing.
NTRK-rearranged spindle cell neoplasms (NTRK-RSCNs) represent an emerging group of rare tumours defined using molecular means. To the best of our knowledge, there have been no large series of reports about this tumour in the Chinese population in English full-text articles. Herein, we present 13 NTRK-RSCNs with peculiar characteristics. Ten of the 13 (77%) patients were children without sex differences. The tumour locations included six trunks, four extremities, two recta, and one small bowel. The histological morphology included four lipofibromatosis-like neural tumour (LPF-NT)-like, eight malignant peripheral nerve sheath tumours (MPNST)/fibrosarcoma-like, and one extremely rare myxofibrosarcoma-like pattern. Immunohistochemically, all cases were CD34, pan-TRK and TRK-A positive, SOX-10 negative, and H3K27me3 intact. S-100 protein expression was identified in 11 of 13 (85%) cases. Genetically, NTRK1 rearrangements were considered positive (7/13, 54%) or suspicious for positivity (6/13, 46%) by fluorescence in situ hybridisation. Next-generation sequencing and Sanger sequencing confirmed NTRK1 fusions with a variety of partner genes, including five LMNA, three TPM3, one SQSTM1, three novel CPSF6, IGR (downstream PMVK), and GAS2L1 genes. Interestingly, the last tumour concurrently harboured a second EWSR1-PBX1 fusion, which has never been reported. Four patients developed local recurrence and two of them suffered metastasis. In our study, NTRK-RSCNs had peculiar fusions that displayed unusual or complicated clinicopathological features. Histological clues and IHC helped streamline a small subset of potential candidates. Although FISH is a powerful technology for identifying NTRK rearrangements, RNA-/DNA-based NGS is recommended for highly suspected cases in which FISH signal patterns are not discernible as classic positive patterns, particularly if targeted therapy is considered.
With the development of technologies, multiple primary lung cancer (MPLC) has been detected more frequently. Although large-scale genomics studies have made significant progress, the aberrant gene mutation in MPLC is largely unclear. In this study, 141 and 44 lesions from single and multiple primary lung adenocarcinoma (SP- and MP-LUAD) were analyzed. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tumor tissue and sequenced by using the next-generation sequencing-based YuanSu450TM gene panel. We systematically analyzed the clinical features and gene mutations of these lesions, and found that there were six genes differently mutated in MP-LUAD and SP-LUAD lesions, including RBM10, CDK4, ATRX, NTRK1, PREX2, SS18. Data from the cBioPortal database indicated that mutation of these genes was related to some clinical characteristics, such as TMB, tumor type, et al. Besides, heterogeneity analysis suggested that different lesions could be tracked back to monophyletic relationships. We compared the mutation landscape of MP-LUAD and SP-LUAD and identified six differentially mutated genes (RBM10, CDK4, ATRX, NTRK1, PREX2, SS18), and certain SNV loci in TP53 and EGFR which might play key roles in lineage decomposition in multifocal samples. These findings may provide insight into personalized prognosis prediction and new therapies for MP-LUAD patients.
Cancer diagnosis and therapeutics have been traditionally based on pathologic classification at the organ of origin. The availability of an unprecedented amount of clinical and biologic data provides a unique window of opportunity for the development of new drugs. What was once treated as a homogeneous disease with a one-size-fits-all approach was shown to be a rather heterogeneous condition, with multiple targetable mutations that can vary during the course of the disease. Clinical trial designs have had to adapt to the exponential growth of targetable mechanisms and new agents, with ensuing challenges that are closer to those experienced with rare diseases and orphan medicines. To face these problems, precision/enrichment and other novel trial designs have been developed, and the concept of histology-agnostic targeted therapeutic agents has emerged. Patients are selected for a specific agent based on specific genomic or molecular alterations, with the same compound used to potentially treat a multiplicity of cancers, granted that the actionable driver alteration is present. There are currently approved drugs for such indications, but this approach has raised issues on multiple levels. This review aims to address the challenges of this new concept and provide insights into possible solutions and frameworks on how to tackle them.
Sensory difficulties represent a crucial issue in the life of autistic individuals. The diagnostic and statistical manual of mental disorders describes both hyper- and hypo-responsiveness to sensory stimulation as a criterion for the diagnosis autism spectrum disorders (ASD). Among the sensory domain affected in ASD, altered responses to tactile stimulation represent the most commonly reported sensory deficits. Although tactile abnormalities have been reported in monogenic cohorts of patients and genetic mouse models of ASD, the underlying mechanisms are still unknown. Traditionally, autism research has focused on the central nervous system as the target to infer the neurobiological bases of such tactile abnormalities. Nonetheless, the peripheral nervous system represents the initial site of processing of sensory information and a potential site of dysfunction in the sensory cascade. Here we investigated the gene expression deregulation in the trigeminal ganglion (which directly receives tactile information from whiskers) in two genetic models of syndromic autism (Shank3b and Cntnap2 mutant mice) at both adult and juvenile ages. We found several neuronal and non-neuronal markers involved in inhibitory, excitatory, neuroinflammatory and sensory neurotransmission to be differentially regulated within the trigeminal ganglia of both adult and juvenile Shank3b and Cntnap2 mutant mice. These results may help in entangling the multifaced complexity of sensory abnormalities in autism and open avenues for the development of peripherally targeted treatments for tactile sensory deficits exhibited in ASD.
In the past decade (2011–2020), there was a growing interest in the discovery and development of orphan drugs for the treatment of rare diseases. However, rare diseases only account for a population of 0.65‰–1‰ which usually occur with previously unknown biological mechanisms and lack of specific therapeutics, thus to increase the demands for the first-in-class (FIC) drugs with new biological targets or mechanisms. Considering the achievements in the past 10 years, a total of 410 drugs were approved by U.S. Food and Drug Administration (FDA), which contained 151 FIC drugs and 184 orphan drugs, contributing to make up significant numbers of the approvals. Notably, more than 50% of FIC drugs are developed as orphan drugs and some of them have already been milestones in drug development. In this review, we aim to discuss the FIC small molecules for the development of orphan drugs case by case and highlight the R&D strategy with novel targets and scientific breakthroughs.
Neurotrophins, such as brain-derived neurotrophic factor (BDNF) and neural growth factor (NGF), are small proteins expressed in the brain and peripheral tissues, which regulate several aspects of neuronal function, including not only neurogenesis, synaptic plasticity, neuroprotection but also programmed cell death. This broad range of effects is a result of a complex downstream signaling pathway, with differential spatial and temporal activation patterns further diversifying their physiological effects. Alterations in neurotrophin levels, or known polymorphisms in neurotrophin genes, have been linked to a variety of disorders, including depression and Alzheimer’s disease (AD). Historically, their therapeutic potential in these disorders has been hampered by the lack of suitable tool molecules for clinical studies. However, recent advancements have led to the development of new therapeutic candidates, which are now in clinical testing.
Teaser: Neurotrophins have key roles in neuronal function and are an attractive target from a therapeutic perspective. Novel therapeutic candidates targeting this biological system are now in clinical testing.
The oncogene (v-src) of Rous sarcoma virus apparently arose by transduction of the chicken gene known as c-src(chicken). We
isolated DNA fragments representative of two src-related loci from recombinant DNA bacteriophage libraries of the human genome.
One of these loci, c-src1(human), appeared to direct the synthesis of a 5-kilobase polyadenylated RNA that presumably encodes
pp60c-src(human). Probes specific for the other locus, c-src2(human), did not hybridize to polyadenylated RNA prepared from
a variety of human cell lines. Partial nucleotide sequence determinations of the loci demonstrated that c-src1(human) is highly
related to chicken c-src and that c-src2(human) is slightly more divergent. The sequences imply that the final two coding
exons of each human locus are identical in length to those of chicken c-src and that the location of an amber stop codon is
unchanged in all three loci. c-src1(human) has been mapped to chromosome 20, and the second locus is located on chromosome
1. We conclude that c-src1(human) is the analog of c-src(chicken) and that the duplicated locus, c-src2(human), may also be
expressed.
Transfection with high molecular weight DNA from a primary stomach cancer induced foci of transformed NIH 3T3 cells, and the transformed cells were tumorigenic in nude mice. By screening with a human Alu-family probe, we isolated the human DNA sequence from the secondary transformant cells. This transforming sequence encompasses about 60 kilobase pairs and is unrelated to known human transforming genes. Examination of homologies between this sequence and retroviral oncogenes revealed that the human transforming sequence is closely related to the v-raf oncogene of murine transforming retrovirus 3611-MSV.
We have isolated a cDNA clone from a human fibroblast cDNA library that contains the entire protein-coding region of a 1.1-kilobase mRNA. This mRNA encodes a 284-amino acid tropomyosin, the primary structure of which most closely resembles smooth muscle tropomyosin. Thus, the expression of both 284-amino acid muscle-type and 247-amino acid non-muscle-type tropomyosins appears to be a normal feature of human non-muscle cells. We also present evidence to suggest that this cytoskeletal tropomyosin and a human skeletal muscle beta-tropomyosin are derived from a common structural gene by an alternative RNA splicing mechanism.
The BJC is owned by Cancer Research UK, a charity dedicated to understanding the causes, prevention and treatment of cancer and to making sure that the best new treatments reach patients in the clinic as quickly as possible. The journal reflects these aims. It was founded more than fifty years ago and, from the start, its far-sighted mission was to encourage communication of the very best cancer research from laboratories and clinics in all countries. The breadth of its coverage, its editorial independence and it consistent high standards, have made BJC one of the world's premier general cancer journals. Its increasing popularity is reflected by a steadily rising impact factor.
A new technique for assaying infectivity of adenovirus 5 DNA has been developed. Viral DNA was diluted in isotonic saline containing phosphate at a low concentration, and calcium chloride was added, resulting in the formation of a calcium phosphate precipitate. DNA coprecipitated with the calcium phosphate and, when the resulting suspension was added to human KB cell monolayers, became adsorbed to the cells. Following adsorption, uptake of DNA into the cells occurred during an incubation in liquid medium at 37 ° in the continued presence of extra calcium chloride.For adenovirus 5 DNA the assay resulted in up to 100-fold more plaques than could be obtained using DEAE-dextran. Furthermore a reproducible relationship between amounts of DNA inoculated per culture and numbers of plaques produced was demonstrated. The assay was most efficient at high DNA concentrations (10–30 μg/ml); below this range the addition of carrier DNA was necessary for optimum results.In addition to adenovirus 5 DNA, the technique has been used successfully to assay infectivity of DNA from adenovirus 1 and simian virus 40.
The complete (172,282 base pairs) nucleotide sequence of the B95-8 strain of Epstein-Barr virus has been established using the dideoxynucleotide/M13 sequencing procedure. Many RNA polymerase II promoters have been mapped and the mRNAs from these promoters have been assigned to the latent or early/late productive virus cycles. Likely protein-coding regions have been identified and three of these have been shown to encode a ribonucleotide reductase, a DNA polymerase and two surface glycoproteins.
The muscle tropomyosin I (mTm I) gene from Drosophila melanogaster has been analyzed and shown to express a complex transcription
unit consisting of two sets of tissue-specific mRNAs. A 1.3- and 1.6-kilobase set of mRNAs is expressed during myogenesis
in embryos, and in myogenic cell cultures. The mRNAs encode a 34,000-dalton muscle tropomyosin isoform. The same mTm I gene
expresses a different set of 1.7- and 1.9-kilobase mRNAs in thoracic flight muscle tissue of the adult. The thorax RNAs encode
a new tropomyosin isoform resolved on two-dimensional gels. The structure of the gene has been determined, and we show that
the embryonic and thoracic mRNAs are generated by alternative splicing. The alternate exon splicing patterns determine a different
27 amino acids at the carboxy-terminal end of the two tropomyosin isoforms. These results show that the carboxy-terminal domain
of tropomyosin is highly regulated in determining tropomyosin function. The results also show that contractile protein isoforms
can be generated by single as well as multiple genes.
A cDNA library of approximately equal to 9,000 members has been prepared from chicken smooth muscle mRNA by using the plasmid expression vector pUC8. Addition of Sal I and EcoRI linkers at different stages during the preparation of the cDNA resulted in a population of molecules, most of which had EcoRI linkers at the end of the cDNA that corresponded to the 5' end of the template mRNA and Sal I linkers at the end that corresponded to the 3' end of the mRNA. The cDNA molecules then were inserted into a EcoRI-Sal I-cut plasmid vector, pUC8, that contains the transcriptional and translational start sequences from the lacZ gene upstream of the EcoRI site. The sequential addition of the linkers to the cDNA ensured that most of the cDNAs were inserted into pUC8 in the proper orientation for expression. The colonies were replica plated onto nitrocellulose filters and lysed in situ with chloroform vapor. The library was screened for colonies producing products immunologically related to chicken tropomyosin by incubating the filters first with a rabbit antitropomyosin antibody and second with a 125I-labeled goat anti-rabbit IgG. Two colonies were detected that reacted specifically with the antisera. Plasmids from both clones have been partially subjected to sequence analysis; both plasmids contain cDNAs that encode tropomyosin. These protocols are potentially useful for the identification of cDNA clones for genes expressed at low levels from large cDNA expression libraries.
Each of six peptides derived from the human epidermal growth factor (EGF) receptor very closely matches a part of the deduced sequence of the v-erb-B transforming protein of avian erythroblastosis virus (AEV). In all, the peptides contain 83 amino acid residues, 74 of which are shared with v-erb-B. The AEV progenitor may have acquired the cellular gene sequences of a truncated EGF receptor (or closely related protein) lacking the external EGF-binding domain but retaining the transmembrane domain and a domain involved in stimulating cell proliferation. Transformation of cells by AEV may result, in part, from the inappropriate acquisition of a truncated EGF receptor from the c-erb-B gene.
Deletion experiments have defined two stretches of DNA (genetic elements), lying close to the promoter for a human gene for metallothionein, that separately mediate the induction of the gene by heavy metal ions, particularly cadmium, and by glucocorticoid hormones. The element responsible for induction by cadmium is duplicated, yet a single copy is fully functional; the element responsible for induction by glucocorticoid hormones is coincident with the DNA-binding site for the glucocorticoid hormone receptor.
We have deduced the entire 1,370-amino-acid sequence of the human insulin receptor precursor from a single complementary DNA clone. The precursor starts with a 27-amino-acid signal sequence, followed by the receptor α-subunit, a precursor processing enzyme cleavage site, then the β-subunit containing a single 23-amino-acid transmembrane sequence. There are sequence homologies to human epidermal growth factor receptor and the members of the src family of oncogene products.
Equine platelet β tropomyosin (247 residues), like rabbit skeletal muscle α tropomyosin (284 residues) has a repeating pattern of amino acid residues characterisitic of a coiled-coil structure. When compared with the muscle protein, it is extended by 5 residues at the NH2-terminus and possesses two 21 residue deletions (positions 23–43 and 60–80 of the muscle sequence). The two proteins are highly conserved from residues 81–260, but are significantly different at their COOH-termini (residues 261–284). These differences in platelet tropomyosin can be correlated with its diminshed head-to-tail polymerization, a weaker interaction with F-actin and a reduced affinity for muscle troponin and the T1 fragment of troponin-T.
A procedure is described for screening bacterial colonies containing recombinant plasmids by nucleic acid hybridization at high density, i.e., at 100 000 colonies per 150 mm diameter plate. Small colonies are established on nitrocellulose filters from which they can be faithfully replicated to additional filters. Chloramphenicol amplification may be carried out in situ before screening. The filters may be kept frozen for long-term storage of colonies which may be further replicated after thawing.
The human homologues of several independent viral oncogenes, each of which encodes tyrosine-specific protein kinases, have been identified. Of these, three (v-src, v-yes and v-fes/fps) are known to exhibit considerable sequence homology, particularly in the regions of their phosphorylation acceptor sites. In the present study, sequences encoding the tyrosine phosphorylation acceptor sites of the Abelson murine leukaemia virus oncogene, v-abl, and its human cellular homologue, c-abl, have been identified and their nucleic acid sequences determined. Our results establish extensive homology between this region of c-abl and acceptor domains of the v-src, v-yes and v-fes/fps family of viral oncogenes, as well as more distant relatedness to the catalytic chain of the mammalian cyclic AMP-dependent protein kinase. These findings suggest that, of the homologues of retroviral oncogenes with tyrosine protein kinase activity examined to date, all were probably derived from a common progenitor and may represent members of a diverse family of cellular protein kinases.
The complete 1,210-amino acid sequence of the human epidermal growth
factor (EGF) receptor precursor, deduced from cDNA clones derived from
placental and A431 carcinoma cells, reveals close similarity between the
entire predicted ν-erb-B mRNA oncogene product and the receptor
transmembrane and cytoplasmic domains. A single transmembrane region of
23 amino acids separates the extracellular EGF binding and cytoplasmic
domains. The receptor gene is amplified and apparently rearranged in
A431 cells, generating a truncated 2.8-kilobase mRNA which encodes only
the extracellular EGF binding domain.
DNA can be sequenced by a chemical procedure that breaks a terminally labeled DNA molecule partially at each repetition of a base. The lengths of the labeled fragments then identify the positions of that base. We describe reactions that cleave DNA preferentially at guanines, at adenines, at cytosines and thymines equally, and at cytosines alone. When the products of these four reactions are resolved by size, by electrophoresis on a polyacrylamide gel, the DNA sequence can be read from the pattern of radioactive bands. The technique will permit sequencing of at least 100 bases from the point of labeling.
This paper describes a method of transferring fragments of DNA from agarose gels to cellulose nitrate filters. The fragments can then be hybridized to radioactive RNA and hybrids detected by radioautography or fluorography. The method is illustrated by analyses of restriction fragments complementary to ribosomal RNAs from Escherichia coli and Xenopus laevis, and from several mammals.
We have deduced the entire 1,370-amino-acid sequence of the human insulin receptor precursor from a single complementary DNA clone. The precursor starts with a 27-amino-acid signal sequence, followed by the receptor alpha-subunit, a precursor processing enzyme cleavage site, then the beta-subunit containing a single 23-amino-acid transmembrane sequence. There are sequence homologies to human epidermal growth factor receptor and the members of the src family of oncogene products.
Human chronic myelogenous leukaemia is characterized by a reciprocal translocation between chromosomes 9 and 22 resulting in an abbreviated form of chromosome 22 and the transfer of the abl cellular oncogene from chromosome 9 into the bcr gene of chromosome 22. Characterization of an 8-kilobase RNA specific to chronic myelogenous leukaemia shows it to be a fused transcript of the two genes. The fused protein that would be produced is probably involved in the malignant process.
A novel transforming gene was detected by transfection of NIH 3T3 cells with human lymphoma DNA. The tumor DNA induced a single focus in primary transfections, whereas DNAs of transformed NIH cells induced transformation with high efficiencies in secondary and tertiary assays. Molecular clones spanning about 37 kb of human sequence were isolated from tertiary transformant DNA. Blot hybridization indicated that the transforming gene consisted of two segments that were unlinked in both normal human and primary lymphoma DNAs. The two segments of human DNA were cotranscribed in transformed NIH cells but not in any human cells examined. The transforming gene thus appeared to be activated by recombination between two unlinked human DNA segments, possibly by cointegration during transfection.
The cell-derived domain of Gardner-Rasheed feline sarcoma virus (GR-FeSV) consists of a gamma-actin- and a tyrosine-specific protein kinase-encoding sequence designated v-fgr. By utilizing a v-fgr probe, it was possible to detect related sequences present at low copy number in DNAs of a variety of mammalian species and to isolate a human fgr homologue. Comparative studies revealed that this human DNA clone represented all but 200 base pairs of v-fgr. Analysis of human genomic DNA demonstrated that the fgr protooncogene was distinct from the cellular homologues of other retrovirus onc genes. In addition, the fgr protooncogene was localized to the distal portion of the short arm of human chromosome 1 at p36.1-36.2 by in situ hybridization. Taken together, our findings establish that the fgr protooncogene is a unique member of the tyrosine kinase gene family.
Tropomyosins are a closely related family of proteins with a dimeric alpha-coiled-coil structure. Skeletal isoforms are composed of two types of subunits, alpha and beta which, in turn, are assorted into two main molecular species alpha alpha and alpha beta. Both isoforms are present in different molar ratios in individual skeletal muscle types. In small mammals, however, only alpha-chain is expressed in cardiac muscle. Tropomyosin, in association with the troponin complex (troponin-I, -T and -C) plays a central role in the Ca2+-dependent regulation of vertebrate striated muscle contraction. On the other hand, despite structural similarities with the striated isoforms, the function of this protein in smooth muscle and non-muscle cells remains unknown, because in these cells contraction is thought to be regulated by myosin-linked processes independently of tropomyosin. Here we report the nucleotide sequences of cloned complementary DNAs for rat striated and smooth muscle alpha-tropomyosin. Comparison of the derived amino-acid sequences reveals the existence of tissue-specific peptides that delimit the putative troponin-I and troponin-T binding domains of tropomyosin. S1-nuclease mapping studies reveal the existence of three distinct alpha-tropomyosin messenger RNA isoforms each encoding a different protein; these isoforms are tissue-specific, developmentally regulated and most probably encoded by the same gene.
Utilizing DNA transfection analysis with the continuous NIH 3T3 cell line as assay cell, we and other have observed that as many as 10-50% of human haematopoietic tumours contain oncogenes, the vast majority of which are members of the ras proto-oncogene family. In addition, Cooper and co-workers have reported the detection and isolation of specific oncogenes, B-lym and T-lym, which appear to be activated in human and rodent tumours of certain B and T lymphoid cells, respectively. In surveying human haematopoietic malignancies, we observed that DNA of a primary human diffuse B-cell lymphoma induced an unusual transformed focus on transfection of NIH 3T3 cells. Here, we report the molecular cloning and physical characterization of this human oncogene, whose transforming activity was shown to reside within a human DNA sequence of 45 kilobases (kb) cloned in a cosmid vector. Its properties distinguish it from previously reported retroviral or nonretroviral oncogenes.
Cellular transforming genes can be detected in human tumours by DNA-mediated transfection into NIH 3T3 mouse fibroblasts. The activated transforming genes have been, in most cases, members of the ras gene family, of which the most frequently found is the c-Ki-ras oncogene and least frequently the c-Ha-ras gene. An increasing number of studies has identified the presence of activated N-ras (which has no known viral homologue) in human tumour cell lines. Furthermore, other transforming genes, distinct from the ras gene family, have been reported in B-and T-cell lymphomas. The activation of c-Ha-ras and N-ras has been described in some cell lines derived from cases of human malignant melanoma. Here we describe the presence of transforming activity in the DNA from a human melanoma cell line which shows weak homology with members of the ras oncogene family.
We have developed a sensitive bioassay for transforming genes based on the tumorigenicity of cotransfected NIH3T3 cells in
nude mice. The assay differs substantially from the NIH3T3 focus assay. Using it, we have detected the transfer of three transforming
genes from the DNA of MCF-7, a human mammary carcinoma cell line. One of these is N-ras, which is amplified in MCF-7 DNA.
The other two, which we have called mcf2 and mcf3, do not appear to be related to known oncogenes. We cannot detect their
transfer by using the NIH3T3 focus assay. We do not yet know whether either mcf2 or mcf3 is associated with genetic abnormalities
in MCF-7 cells.
We have observed three effects of deletion mutations on polyadenylation of late SV40 mRNAs. The first class of mutants lack segments (-3 to -14 bp) between the 5-AAUAAA-3' and normal poly(A) site. These mutants produce mRNas polyadenylated at new sites, downstream from the wild-type site. The poly(A) site is moved farther downstream as the deletions become larger; as a result, polyadenylation always occurs within an 11-19 nucleotide range from the AAUAAA sequence. The second class of mutants lack segments (-12 to -30 bp) between the AAUAAA sequence and the coding region of the mRNA. The poly(A) site for only one of these mutants was studied (dl1457, -12 bp). In this case, the spatial relationship between AAUAAA and poly(A) site is altered. dl1457 produces a class of mRNAs polyadenylated at the first Ca following the AAUAAA sequence, as well as other mRNAs polyadenylated farther downstream. Finally, a 16 bp deletion that includes the AAUAAA sequence prevents poly(A) addition.
From the complete nucleotide sequence of the genome of the avian sarcoma virus Y73, we have predicted amino acid sequence of p90 gag-yes, the product of the transforming gene. Contrary to previous evidence from molecular hybridization studies p90 gag-yes was found to have much homology with the transforming gene product p60 src of Rous sarcoma virus, suggesting that the cellular counterparts of the two (c-yes and c-src) originated from a common prototype sequence.
Site-directed mutagenesis techniques were used to construct defined point mutations within the src gene of the Prague A strain of Rous sarcoma virus. Bisulfite mutagenesis at a Bg/I restriction site in the src gene yielded three mutations which contained the same single base change, a guanine-to-adenine transition. The resulting genomes encoded an src protein containing a substitution of threonine for alanine at amino acid position 433. Transfection of chicken cells with mutagenized DNA did not result in cellular transformation even though the cells produced a pp60src. Immune complexes containing mutant pp60src did not phosphorylate immunoglobulin G heavy chain or casein.
We have isolated and characterized a human genomic DNA sequence that defines a family of closely related sequences. At least one member of this family expresses a 2.5 X 10(3) base messenger RNA transcript encoding a 30,000 molecular weight tropomyosin in human fibroblasts. The coding sequence of this mRNA but not the non-coding sequence is also related to that of a 1.1 X 10(3) base mRNA encoding a 36,000 molecular weight non-muscle tropomyosin. This demonstrates the existence of at least two functional genes encoding human non-muscle tropomyosins.
The human c-ab1 oncogene maps within the region (q34-qter) of chromosome 9 which is translocated to chromosome 22, the Philadelphia (Ph') chromosome, in chronic myelocytic leukaemia (CML). The position of the Ph' chromosomal break point is shown to be variable and, in one CML patient, has been localized immediately 5' of, or within, the c-ab1 oncogene. A DNA restriction fragment corresponding to this site has been molecularly cloned and shown to represent a chimaeric fragment of DNA from chromosomes 9 and 22.
The nucleotide sequence of the region of Gardner-Rasheed feline sarcoma virus (GR-FeSV) encoding its primary translation product,
p70gag-fgr, has been determined. From the nucleotide sequence, the amino acid sequence of this transforming protein was deduced.
Computer analysis indicates that a portion of P70gag-fgr has extensive amino acid sequence homology with actin, a eukaryotic
cytoskeletal protein. A second region of P70gag-fgr is closely related to the tyrosine-specific kinase gene family. Thus,
the v-fgr oncogene appears to have arisen as a result of recombinational events involving two distinct cellular genes, one
coding for a structural protein and the other for a protein kinase.
The complete 1,210-amino acid sequence of the human epidermal growth factor (EGF) receptor precursor, deduced from cDNA clones derived from placental and A431 carcinoma cells, reveals close similarity between the entire predicted v-erb-B mRNA oncogene product and the receptor transmembrane and cytoplasmic domains. A single transmembrane region of 23 amino acids separates the extracellular EGF binding and cytoplasmic domains. The receptor gene is amplified and apparently rearranged in A431 cells, generating a truncated 2.8-kilobase mRNA which encodes only the extracellular EGF binding domain.
Molecular cloning of the transforming gene from a chemically transformed human osteosarcoma-derived cell line enables the gene to be mapped to chromosome 7 (7p11.4-7qter) and by this criterion and by direct hybridization to be shown to be unrelated to known oncogenes.
The identification and isolation of oncogenes capable of inducing malignant transformation on transfection into rodent cells from human tumour cells has opened the possibility of deciphering the processes involved in human carcinogenesis. With the exception of three human lymphomas1, the human transforming genes so far identified have been detected in established tumour cell lines1-8, raising the possibility that they might have been activated during in vitro manipulation of the cells. However, we report here that unmanipulated human solid tumours, including carcinomas of the colon (two), lung and pancreas and an embryonal rhabdomyosarcoma, also contain dominant transforming genes. The carcinomas of the lung and pancreas and the rhabdomyosarcoma possessed a common oncogene which, like that isolated from human LX-1 lung carcinoma cells9, shares sequences with the onc gene of the Kirsten strain of murine sarcoma virus (MSV). We also show that several other human tumour cell lines, including those established from carcinomas of the colon (A2233), lung (A427 and A2182), gall bladder (A1604) and urinary bladder (A1698), possess the same oncogene. Thus a variety of human tumours, regardless of their clinical manifestations, contain a common transforming gene.
The molecularly cloned, long terminal repeat (LTR) of the Moloney sarcoma virus (M-MSV) provirus has been covalently linked
to c-mos, the cellular homolog of the M-MSV-specific sequence, v-mos. These newly constructed clones lack any M-MSV-derived
sequences other than the LTR, but in DNA transfection assays they transform cells as efficiently as cloned subgenomic M-MSV
fragments containing both v-mos and LTR. Cells transformed by LTR:c-mos hybrid molecules contain additional copies of mos
DNA, and several size classes of polyadenylated RNA's with sequence homology to mos. The activation of the transforming potential
of c-mos by the proviral LTR suggests a model whereby LTR-like elements could activate other normal cell sequences with oncogenic
potential.