Figure 5 - uploaded by Shuk-Mei Ho
Content may be subject to copyright.
AP-2 regulates ERb gene expression. (a) Forced expression of AP-2a or -2g increased ERb mRNA level. PC-3 cells were transfected with plasmids expressing AP-2a or -2g, with or without AP-2D using the Nucleofector. After 24 h, cellular ERb transcript levels were quantified by real-time RT–PCR. Unrelated vector pGEM-T was used as the DNA dosage control in all transfections. (b) Transfection of siRNA for AP-2a and -2g into PC-3 cells reduced levels of AP-2 and ERb transcripts. Levels of transcripts in PC-3 cells transfected with siRNA negative control (siControl) were arbitrary assigned a value of 1. (c) Forced expression of AP-2a or -2g increased ERb 0N promoter activity in a dose-dependent manner in DU145 cells. Co-expression of AP-2D resulted in the repression of promoter activity. Asterisk denotes a significant difference (Po0.01). Bars are mean7s.d. of three independent experiments.
Source publication
We reported previously that the loss of expression of estrogen receptor (ER)-beta during the development of prostate cancer (PCa) is associated with methylation of a CpG island located in the 5'-flanking sequence of the 0N promoter. Three methylation hotspots, referred to as centers 1, 2 and 3, were identified in the CpG island. In this study, we d...
Contexts in source publication
Context 1
... expression or siRNA-mediated knockdown of AP-2 induced concordant changes in ERb expression AP-2a and -2g expression plasmids were transfected with or without a dominant negative AP-2D plasmid into PC-3 cells, in which its ERb 0N promoter is unmethylated ( Zhu et al., 2004), and thus interaction between AP-2 and its cis-regulatory element will not be hindered by methylation. Real-time RT-PCR demon- strated that forced expression of AP-2a or -2g, but not AP-2b (data not shown), in PC-3 cells induced significant increases (135-185%) in ERb transcripts as compared with the empty vector control (Figure 5a). Such effects can be reversed by co-transfecting AP-2D into the same system, demonstrating the specificity of AP-2. ...
Context 2
... effects can be reversed by co-transfecting AP-2D into the same system, demonstrating the specificity of AP-2. Conversely, siRNA-mediated double knockdown (Figure 5b) of AP-2a and -2g transcripts in PC-3 cells resulted in 76-79% reduction of AP-2 transcripts and 81% decrease in ERb mRNA. Further investigation using DU145 cell, which expresses lower endogenous AP-2, revealed that AP-2a and -2g, but not AP-2b (data not shown), can upregulate 0N promoter activity in a dose-dependent manner, and its activity can be sup- pressed by AP-2D co-expression ( Figure 5c). ...
Context 3
... siRNA-mediated double knockdown (Figure 5b) of AP-2a and -2g transcripts in PC-3 cells resulted in 76-79% reduction of AP-2 transcripts and 81% decrease in ERb mRNA. Further investigation using DU145 cell, which expresses lower endogenous AP-2, revealed that AP-2a and -2g, but not AP-2b (data not shown), can upregulate 0N promoter activity in a dose-dependent manner, and its activity can be sup- pressed by AP-2D co-expression ( Figure 5c). ...
Similar publications
Pathological characteristics of Alzheimer's disease (AD) include amyloid-beta (Abeta) plaques. Abeta is derived from the Abeta peptide precursor protein (APP) by gamma- and beta-secretases, the latter known as beta-site APP-cleaving enzyme 1 (BACE1, or herein BACE). We have also described potentially important regions in the promoter of BACE, which...
Mouse aphakia (ak) is a recessive phenotype that spontaneously occurs in the 129/Sv-SlJ strain and is characterized by small eyes that lack a lens. We have recently identified a homeobox-containing gene, Pitx3, and have shown that it is expressed in the developing lens and maps to chromosome 19 close to ak in mouse. Human PITX3 gene was found to un...
Involucrin is an integral component of the cornified envelope which is a characteristic feature of the differentiated keratinocyte. Involucrin expression is tightly linked to the onset of differentiation and first expressed in the immediate suprabasal layers of the epidermis. We have identified a transcriptional response element within the distal 5...
Citations
... For instance, TFAP2A potentiates lung adenocarcinoma metastasis and stimulates angiogenesis in lung cancer cells with acquired resistance to anlotinib [37,38]; TFAP2A-mediated activation of E2F and EZH2 drives melanoma metastasis [39]. TFAP2A, along with TFAP2B and TFAP2C, are known to be expressed in breast tissue and coordinated the growth and development of the breast via regulation of several breast-related genes such as human epidermal growth factor receptor-2(HER2) and estrogen receptor (ER) [40][41][42][43]. In contrast to TFAP2C, extensive research indicates that TFAP2A plays a significant tumor suppressive role in breast tissues, exhibiting functions crucial for growth suppression and maintenance of the differentiated state [43][44][45]. ...
Background
Triple-negative breast cancer (TNBC) represents a highly aggressive subset of breast malignancies characterized by its challenging clinical management and unfavorable prognosis. While TFAP2A, a member of the AP-2 transcription factor family, has been implicated in maintaining the basal phenotype of breast cancer, its precise regulatory role in TNBC remains undefined.
Methods
In vitro assessments of TNBC cell growth and migratory potential were conducted using MTS, colony formation, and EdU assays. Quantitative PCR was employed to analyze mRNA expression levels, while Western blot was utilized to evaluate protein expression and phosphorylation status of AKT and ERK. The post-transcriptional regulation of TFAP2A by miR-8072 and the transcriptional activation of SNAI1 by TFAP2A were investigated through luciferase reporter assays. A xenograft mouse model was employed to assess the in vivo growth capacity of TNBC cells.
Results
Selective silencing of TFAP2A significantly impeded the proliferation and migration of TNBC cells, with elevated TFAP2A expression observed in breast cancer tissues. Notably, TNBC patients exhibiting heightened TFAP2A levels experienced abbreviated overall survival. Mechanistically, TFAP2A was identified as a transcriptional activator of SNAI1, a crucial regulator of epithelial-mesenchymal transition (EMT) and cellular proliferation, thereby augmenting the oncogenic properties of TFAP2A in TNBC. Moreover, miR-8072 was unveiled as a negative regulator of TFAP2A, exerting potent inhibitory effects on TNBC cell growth and migration. Importantly, the tumor-suppressive actions mediated by the miR-8072/TFAP2A axis were intricately associated with the attenuation of AKT/ERK signaling cascades and the blockade of EMT processes.
Conclusions
Our findings unravel the role and underlying molecular mechanism of TFAP2A in driving tumorigenesis of TNBC. Targeting the TFAP2A/SNAI1 pathway and utilizing miR-8072 as a suppressor represent promising therapeutic strategies for treating TNBC.
... In prostate cancer, TFAP2A can bind to the ESR2 promoter region to activate expression [112]. ERβ may exert its tumor promotion effects by enhancing cell invasion and metastasis [113][114][115]. ...
The transcription factor family activator protein 2 (TFAP2) is vital for regulating both embryonic and oncogenic development. The TFAP2 family consists of five DNA-binding proteins, including TFAP2A, TFAP2B, TFAP2C, TFAP2D and TFAP2E. The importance of TFAP2 in tumor biology is becoming more widely recognized. While TFAP2D is not well studied, here, we mainly focus on the other four TFAP2 members. As a transcription factor, TFAP2 regulates the downstream targets directly by binding to their regulatory region. In addition, the regulation of downstream targets by epigenetic modification, posttranslational regulation, and interaction with noncoding RNA have also been identified. According to the pathways in which the downstream targets are involved in, the regulatory effects of TFAP2 on tumorigenesis are generally summarized as follows: stemness and EMT, interaction between TFAP2 and tumor microenvironment, cell cycle and DNA damage repair, ER- and ERBB2-related signaling pathway, ferroptosis and therapeutic response. Moreover, the factors that affect TFAP2 expression in oncogenesis are also summarized. Here, we review and discuss the most recent studies on TFAP2 and its effects on carcinogenesis and regulatory mechanisms.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12967-023-04189-1.
... In addition, the ERβ receptor has been reported to inhibit cell growth, decrease epithelial-mesenchymal transition-related aggressive behavior and induce apoptosis in PCa cells (5,6). Although the results in the literature are conflicting, ERα is associated with malignant transformation from high-grade prostatic intraepithelial neoplasia (PIN) to PCa, while ERβ has antiproliferative, antiinvasive and pro-apoptotic effects (7)(8)(9)(10)(11)(12)(13)(14). ...
Estrogen receptors in prostate cancer (PCa) are a subject of debate. The aim of the present study was to investigate whether estrogen receptor-α (ERα) and estrogen receptor-β (ERβ) impact the biochemical recurrence (BCR) of non-metastatic PCa after surgery. Following the application of the exclusion criteria, data from 108 patients who underwent laparoscopic radical prostatectomy between January 2011 and December 2019 were retrospectively evaluated. A total of 36 patients with BCR constituted the BCR group. The control group was formed using the Propensity Score Matching (PSM) method with a 1:2 ratio, including parameters with well-studied effects on BCR. The median follow-up time was 74.3 (range, 30-127.5) months in the BCR group and 66.6 (range, 31.5-130) months in the control group. Pathology specimens from the two groups were immunohistochemically stained with ERα and ERβ antibodies. Logistic regression analysis and survival analysis were performed. No differences in clinicopathological characteristics were detected between the two groups. The patients with ERα(-)/ERβ(+) staining results had a significantly fewer BCRs than other patients (P=0.024). In the logistic regression analysis, patients with ERα(-)/ERβ(+) PCa also had a significantly lower risk of recurrence (P=0.048). In the survival analysis, the 5-year BCR-free survival rate of patients with ERα(-)/ERβ(+) PCa was higher than that of other patients (85.7 vs. 66.1%; P=0.031). Excluding the effects of well-studied risk factors for recurrence by the PSM method, the present study showed that ERα and ERβ have prognostic value for non-metastatic PCa. The 5-year BCR-free survival rate is significantly higher in patients whose PCa tissue has ERα(-)/ERβ(+) staining results.
... NFkB FOXP3, and AP-2 ( Figure 6A). The identified TFs are reported to be regulated by estrogen or ERs (38)(39)(40)(41)(42)(43)(44)(45)(46)(47). Moreover, the predicted binding sites for TFs overlapped with the hypermethylated CpGs ( Figures 6A, B). ...
... The 27-HC-mediated transcriptional downregulation of PTDSS2 is well correlated with the PTDSS2 deletion phenotype observed in many cancers. In silico analysis of putative TFs that binds to the hypermethylated regions of PTDSS2 gene promoter showed ER-a, GATA-1, GATA-2 P53, GR-alpha, Sp1, FOXA1, NFkB, FOXP3, and AP-2 that are regulated by estrogen or ERs (38)(39)(40)(41)(42)(43)(44)(45)(46)(47). It is understood that methylation can affect binding affinities of TF depending on the position of methylated CpGs within their binding motifs (48). ...
... It is understood that methylation can affect binding affinities of TF depending on the position of methylated CpGs within their binding motifs (48). TFs like NFkB and AP-2 are known to repress from binding when there is methylation at binding sites (47,48). Thus, this connotes that 27-HC-mediated promoter hypermethylation and downregulation of PTDSS2 gene are most likely by affecting the local dynamics of TFs. ...
27-hydroxycholesterol (27-HC) is the first known endogenous selective estrogen receptor modulator (SERM), and its elevation from normal levels is closely associated with breast cancer. A plethora of evidence suggests that aberrant epigenetic signatures in breast cancer cells can result in differential responses to various chemotherapeutics and often leads to the development of resistant cancer cells. Such aberrant epigenetic changes are mostly dictated by the microenvironment. The local concentration of oxygen and metabolites in the microenvironment of breast cancer are known to influence the development of breast cancer. Hence, we hypothesized that 27-HC, an oxysterol, which has been shown to induce breast cancer progression via estrogen receptor alpha (ERα) and liver X receptor (LXR) and by modulating immune cells, may also induce epigenetic changes. For deciphering the same, we treated the estrogen receptor-positive cells with 27-HC and identified DNA hypermethylation on a subset of genes by performing DNA bisulfite sequencing. The genes that showed significant DNA hypermethylation were phosphatidylserine synthase 2 (PTDSS2), MIR613, indoleamine 2,3-dioxygenase 1 (IDO1), thyroid hormone receptor alpha (THRA), dystrotelin (DTYN), and mesoderm induction early response 1, family member 3 (MIER). Furthermore, we found that 27-HC weakens the DNMT3B association with the ERα in MCF-7 cells. This study reports that 27-HC induces aberrant DNA methylation changes on the promoters of a subset of genes through modulation of ERα and DNMT3B complexes to induce the local DNA methylation changes, which may dictate drug responses and breast cancer development.
... [121] This implies that the expression of ERβ1 and its isoform is regulated by independent mechanisms. Zhang et al. demonstrated that the ERβ transcription is driven by two promoters 0K and 0N-upstream to 5'most-untranslated exons, preceding exon 1. [122,123] Both promoters were found to be active in normal and cancerous prostate tissues. Promoter 0N with higher transcriptional activity has AP-2 site, whereas promoter 0K has CpG-rich region with lower transcriptional activity than that triggered by promoter 0N. ...
... Zhang et al. demonstrated preferential use of promoter 0N for ERβ1 transcription. [123] Lee et al. extended that these observations to demonstrate that ERβ1 and ERβ2 are transcribed from both promoters 0N and 0K whereas ERβ5 transcription is predominantly initiated from promoter 0K. [124] It was demonstrated that the transcripts transcribed from promoter 0K contain different combinations of untranslated exons 0Xs (0X1-8) which do not contribute to protein expression. ...
Estrogens are implicated in a diverse range of functions varying from reproduction, circulation, skeletal health to neuroprotection. Estrogens are also being increasingly recognized for their pathological contribution to cancers of various organs. This has spurred several investigations on estrogen-initiated signaling mechanisms in various cell types in physiological and pathological conditions. Estrogens exert their biological actions through a class of conventional nuclear receptors known as estrogen receptors (ERs), majorly of two subtypes – ERα and ERβ, both encoded by different genes, and each has multiple isoforms. It is reported that different ER subtypes and their specific isoforms have overlapping and nonoverlapping functions. Moreover, ER functions are highly cell-context specific. Thus, it is difficult to propose a unified scheme for estrogen signaling. Another layer of complexity is added by diverse subcellular localization, i.e., nucleus, plasma membrane, and cytosol, of ERs in estrogen-responsive tissues. Size as well as site dictates the sequence of cellular events triggered by estrogen signaling. This review compiles the existing information on different subtypes, different isoforms, and different sites of subcellular localization of ERs.
... The transcription factors c-jun and CREB can bind to ERβ promoter and promote ERβ transcription [117]. In addition, AP2α and AP2γ, two transcription factors that regulate ERα transcription, bind to ERβ promoter and stimulate ERβ transcription [118]. An evolutionally conserved E-box motif (CAC GTG ) has been identified in the ERβ promoter. ...
Estrogen is a steroid hormone that has critical roles in reproductive development, bone homeostasis, cardiovascular remodeling and brain functions. However, estrogen also promotes mammary, ovarian and endometrial tumorigenesis. Estrogen antagonists and drugs that reduce estrogen biosynthesis have become highly successful therapeutic agents for breast cancer patients. The effects of estrogen are largely mediated by estrogen receptor (ER) α and ERβ, which are members of the nuclear receptor superfamily of transcription factors. The mechanisms underlying the aberrant expression of ER in breast cancer and other types of human tumors are complex, involving considerable alternative splicing of ERα and ERβ, transcription factors, epigenetic and post-transcriptional regulation of ER expression. Elucidation of mechanisms for ER expression may not only help understand cancer progression and evolution, but also shed light on overcoming endocrine therapy resistance. Herein, we review the complex mechanisms for regulating ER expression in human cancer.
... Distinct cis-regulatory sequences in the human ER gene confer a molecular architecture that facilitates alternative splicing in prostate and mammary glands, raising the possibility that these same molecular mechanisms contribute to brainregion specific splicing. For instance, full length hER transcription can be initiated from 2 different promoters characterized as 5' untranslated exons, 0K and 0N, in the prostate and mammary glands (57)(58)(59). In the prostate gland, hER1 and hER2 were predominantly transcribed from the 0N promoter, whereas hER5 was uniquely transcribed from the 0K promoter (58). ...
Estrogen receptor beta (ERβ) is a multifunctional nuclear receptor that mediates the actions of estrogenic compounds. Despite its well defined role in mediating the actions of estrogens, a substantial body of evidence demonstrates that ERβ has broad range of physiological functions that are independent of those normally attributed to estrogen signaling. These functions can, in part, be achieved by the activity of several alternatively spliced isoforms that have been identified for ERβ. This short review will describe structural differences between the ERβ splice variants that are known to be translated into proteins. Moreover, we discuss how these alternative structures contribute to functional differences in the context of both healthy and pathological conditions. This review also describes the principal factors that regulate alternative RNA splicing. The alternatively spliced isoforms of ERβ are differentially expressed according to brain region, age, and hormonal milieu underscoring the likelihood that there are precise cell-specific mechanisms that regulate ERβ alternative splicing. However, despite these correlative data, the molecular factors regulating alternative ERβ splicing in the brain remain unknown. Here, we review the basic mechanisms that regulate alternative RNA splicing and use that framework to make logical predictions about ERβ alternative splicing in the brain. This article is protected by copyright. All rights reserved.
... During progression to malignant cells, normal breast cells show a gradual loss of AP-2α expression. The downregulation or absence of AP-2α expression is associated with many cancers such as cutaneous melanomas (14), breast cancer (15), oral squamous cell carcinoma, colon (16), and prostate cancers (17). In contrast, over-expression of AP-2α is known to suppress cell growth (18) and induce apoptosis in cell lines of breast cancer (19), retinoblastoma (20), and colon and others (21). ...
Background:
The molecular mechanisms of tumor suppressor gene DLEC1 are largely unknown.
Objectives:
In this study, we established DLEC1 over-expression stable clones to study the cellular function of DLEC1 in the colorectal cancer cell line, HCT116.
Materials and methods:
Stable clones with DLEC1 over-expression were first established by the transfection of DLEC1 expression construct pcDNA31DLEC1 in HCT116. On G418 selection, positive stable clones were screened for DLEC1 expression level by conventional reverse transcription-polymerase chain reaction (RT-PCR), and verified by real-time RT-PCR and Western blotting. Subsequently, these stable clones were subjected to colony formation and cell cycle analyses and identification of factors involved in G1 arrest. Lastly, three stable clones, DLEC1-7 (highest DLEC1 expression), DLEC1-3 (lowest expression) and pcDNA31 vector control, were employed to analyze cell proliferation and cell cycle after AP-2α2 knockdown by siRNAs.
Results:
The DLEC1 over-expression was found to reduce the number of colonies in colony formation and to induce G1 arrest in seven clones, and apoptosis in one clone in the cell cycle analysis. Furthermore, regardless of the different cell cycle defects in all eight stable clones, the expression level of transcriptional factor AP-2α2 was found to be elevated. More interestingly, we found that when AP-2α2 was knocked down, DLEC1 over-expression neither suppressed cancer cell growth nor induced G1 arrest, yet, instead promoted cell growth and decreased cells in the G1 fraction. This promotion of cell proliferation and release of G1 cells also seemed to be proportional to DLEC1 expression levels in DLEC1 stable clones.
Conclusions:
DLEC1 suppresses tumor cell growth the presence of AP-2α2 and stimulates cell proliferation in the down-regulation of AP-2α2 in DLEC1 over-expression stable clones of HTC116.
... ER-b is the main estrogen receptor subtype in the prostatic tissue, which serves as a tumor suppressor gene by protecting against uncontrolled cell proliferation in normal prostate [37]. Several tumor suppressor genes (including ER-b) have been reported to be transcriptionally silenced by hypermethylation during cancer development. ...
Estrogen Receptor-β (ER-β), a tumor-suppressor in prostate cancer, is epigenetically repressed by hypermethylation of its promoter. DNA-methyltransferases (DNMTs), which catalyze the transfer of methyl-groups to CpG islands of gene promoters, are overactive in cancers and can be inhibited by DNMT-inhibitors to re-express the tumor suppressors. The FDA-approved nucleoside DNMT-inhibitors like 5-Azacytidine and 5-Aza-deoxycytidine carry notable concerns due to their off-target toxicity, therefore non-nucleoside DNMT inhibitors are desirable for prolonged epigenetic therapy. Disulfiram (DSF), an antabuse drug, inhibits DNMT and prevents proliferation of cells in prostate and other cancers, plausibly through the re-expression of tumor suppressors like ER-β. To increase the DNMT-inhibitory activity of DSF, its chemical scaffold was optimized and compound-339 was discovered as a doubly potent DSF-derivative with similar off-target toxicity. It potently and selectively inhibited cell proliferation of prostate cancer (PC3/DU145) cells in comparison to normal (non-cancer) cells by promoting cell-cycle arrest and apoptosis, accompanied with inhibition of total DNMT activity, and re-expression of ER-β (mRNA/protein). Bisulfite-sequencing of ER-β promoter revealed that compound-339 demethylated CpG sites more efficaciously than DSF, restoring near-normal methylation status of ER-β promoter. Compound-339 docked on to the MTase domain of DNMT1 with half the energy of DSF. In xenograft mice-model, the tumor volume regressed by 24% and 50% after treatment with DSF and compound-339, respectively, with increase in ER-β expression. Apparently both compounds inhibit prostate cancer cell proliferation by re-expressing the epigenetically repressed tumor-suppressor ER-β through inhibition of DNMT activity. Compound-339 presents a new lead for further study as an anti-prostate cancer agent. © 2015 Wiley Periodicals, Inc.
... AP-2 regulates the transcription of ERβ by acting through a methylation hotspot of the 0N promoter in prostate cancer cells. Loss of protein AP-2 allows methylation at the critical AP-2 binding domain in ERβ promoter (46). Interestingly, very recently, a regulation between ERβ2 and ΕRβ1 has been addressed; ERβ2 is proposed to repress ERβ1 transcription, thereby affecting its Metabolism of estrogen receptor β physiological ligand, 3β-adiol. ...
Although androgen receptor (AR) signaling is the main molecular tool regulating growth and function of prostate gland, estrogen receptor beta (ERβ) is involved contributive in the differentiation of prostatic epithelial cells and numerous antiproliferative actions on prostate cancer cells. However, ERβ splice variants have been associated with prostate cancer initiation and progression mechanisms. Nowadays, ERß is a promising target as an anticancer therapy and prevention for prostate cancer. Herein, we review the recent experimental findings of ERβ signaling in prostate.
