Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

X-linked primate-specific melanoma antigen-A11 (MAGE-A11) is a human androgen receptor (AR) coactivator and proto-oncogene expressed at low levels in normal human reproductive tract tissues and at higher levels in castration-resistant prostate cancer where it is required for androgen-dependent cell growth. In this report, we show that MAGE-A11 is targeted for degradation by human p14-ARF, a tumor suppressor expressed from an alternative reading frame of the p16 cyclin-dependent kinase inhibitor INK4a/ARF gene. MAGE-A11 degradation by the proteasome was mediated by an interaction with p14-ARF and was independent of lysine ubiquitination. A dose-dependent inverse relationship between MAGE-A11 and p14-ARF correlated with p14-ARF inhibition of the MAGE-A11-induced increase in androgen-dependent AR transcriptional activity and constitutive activity of a splice variant-like AR. Reciprocal stabilization between MAGE-A11 and AR did not protect against degradation promoted by p14-ARF. p14-ARF prevented MAGE-A11 interaction with the E2F1 oncoprotein and inhibited the MAGE-A11-induced increase in E2F1 transcriptional activity. Post-translational down-regulation of MAGE-A11 promoted by p14-ARF was independent of HDM2, the human homologue of mouse double minute 2, an E3 ubiquitin ligase inhibited by p14-ARF. However, MAGE-A11 had a stabilizing effect on HDM2 in the absence or presence of p14-ARF and cooperated with HDM2 to increase E2F1 transcriptional activity in the absence of p14-ARF. We conclude that degradation of MAGE-A11 promoted by the human p14-ARF tumor suppressor contributes to low levels of MAGE-A11 in nontransformed cells and that higher levels of MAGE-A11 associated with low p14-ARF increase AR and E2F1 transcriptional activity and promote the development of castration-resistant prostate cancer.
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PMID:Post-translational Down-regulation of Melanoma Antigen-A11 (MAGE-A11) by Human p14-ARF Tumor Suppressor. 2633 May 56

The androgen receptor (AR) is a transcriptional factor that has a pivotal role in the development of normal and also cancerous prostate. Therefore, analyzing AR signaling is essential to understand cancerogensis and proliferation of prostate cancer (PCa). Inhibitor of growth 1 (ING1) and ING2 are tumor suppressors with reduced expression in many cancer types. There are also indications of misregulation of ING1 and ING2 in PCa. However, the roles of ING1 and ING2 in PCa and AR signaling are poorly understood. Here, we show that surprisingly the ING1b knockdown (KD) represses AR-mediated transactivation on AR key target genes in the human LNCaP PCa cells. This is associated with growth reduction of LNCaP cells by ING1 KD. In line with this, using Ing1 knockout (KO) mice, we provide further evidence that ING1 deficiency downregulates prostate-specific AR target genes in vivo. Further analyses suggest that KD of ING1b results in induction of both cellular senescence and the cell cycle inhibitor p16 INK4a . The unexpected finding that the ING1 KD results in growth inhibition was further analyzed and can be explained by a compensatory mechanism through enhanced levels of ING2 protein in ING1-deficient condition. Accordingly, the data suggest that ING2 interacts with AR and hampers the AR transcriptional activation, causes growth arrest, and induces cellular senescence. The data further suggest that ING2 upregulates p16 INK4a , which is a novel target for ING2. Taken together, our data suggest that ING2 is a novel corepressor for AR. ING2 levels are increased upon downregulation of ING1 expression indicating a compensatory mechanism and suggests a novel crosstalk between ING1 and ING2 tumor suppressors to inhibit AR signaling and induce cellular senescence in PCa cells.
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PMID:A novel crosstalk between the tumor suppressors ING1 and ING2 regulates androgen receptor signaling. 2730 9

The chromobox 7 (CBX7) protein of the polycomb repressive complex 1 (PRC1) functions to repress transcription of tumor suppressor p16 (INK4a) through long noncoding RNA, ANRIL (antisense noncoding RNA in the INK4 locus) directed chromodomain (ChD) binding to trimethylated lysine 27 of histone H3 (H3K27me3), resulting in chromatin compaction at the INK4a/ARF locus. In this study, we report structure-guided discovery of two distinct classes of small-molecule antagonists for the CBX7ChD. Our Class A compounds, a series including analogues of the previously reported MS452, inhibit CBX7ChD/methyl-lysine binding by occupying the H3K27me3 peptide binding site, whereas our Class B compound, the newly discovered MS351, appears to inhibit H3K27me3 binding when CBX7ChD is bound to RNA. Our crystal structure of the CBX7ChD/MS351 complex reveals the molecular details of ligand recognition by the aromatic cage residues that typically engage in methyl-lysine binding. We further demonstrate that MS351 effectively induces transcriptional derepression of CBX7 target genes, including p16 (INK4a) in mouse embryonic stem cells and human prostate cancer PC3 cells. Thus, MS351 represents a new class of ChD antagonists that selectively targets the biologically active form of CBX7 of the PRC1 in long noncoding RNA- and H3K27me3-directed gene transcriptional repression.
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PMID:Structure-Guided Discovery of Selective Antagonists for the Chromodomain of Polycomb Repressive Protein CBX7. 2732 34

ARF couples with TP53 in a canonical signaling pathway to activate cellular senescence for tumor suppressive function under oncogenic insults. However, the mechanisms on aberrant elevation of ARF in cancers are still poorly understood. We previously showed that ARF (p14ARF in human and p19Arf in mouse) elevation correlates with PTEN loss and stabilizes SLUG to reduce cell adhesion in prostate cancer (PCa). Here we report that ARF is essential for MMP7 expression, E-Cadherin decrease and the anchorage loss to the extracellular matrix (ECM) in PCa in vitro and in vivo. We found that Mmp7 is aberrantly elevated in cytosol and nucleus of malignant prostate tumors of Pten/Trp53 mutant mice. Interestingly, p19Arf deficiency strikingly decreases Mmp7 levels but increases E-Cadherin in Pten/Trp53/p19Arf mice. ARF knockdown markedly reduces MMP7 in human PCa cells. Conversely, tetracycline-inducible expression of ARF increases MMP7 with a decrease of E-Cadherin in PCa cells. Importantly, MMP7 physically binds ARF to show the co-localization in nucleus. Co-expression of MMP7 and ARF promotes cell migration, and MMP7 knockdown decreases wound healing in PCa cells. Furthermore, MMP7 elevation correlates with ARF expression in advanced human PCa. Our findings reveal for the first time that the crosstalk between ARF and MMP7 in nucleus contributes to ECM network in tumor microenvironments in vivo, implicating a novel therapeutic target for advanced PCa treatment.
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PMID:MMP7 interacts with ARF in nucleus to potentiate tumor microenvironments for prostate cancer progression in vivo. 2735 44

Several studies have suggested that long non-coding RNA (lncRNA) gene polymorphisms are associated with cancer risk. In the present study, we conducted a meta-analysis related to studies on the association between lncRNA single-nucleotide polymorphisms (SNPs) and the overall risk of cancer. A total of 12 SNPs in five common lncRNA genes were finally included in the meta-analysis. In the lncRNA antisense non-coding RNA (ncRNA) in the INK4 locus (ANRIL), the rs1333048 A/C, rs4977574 A/G, and rs10757278 A/G polymorphisms, but not rs1333045 C/T, were correlated with overall cancer risk. Our study also demonstrated that other SNPs were correlated with overall cancer risk, namely, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1, rs619586 A/G), HOXA distal transcript antisense RNA (HOTTIP, rs1859168 A/C), and highly up-regulated in liver cancer (HULC, rs7763881 A/C). Moreover, four prostate cancer-associated ncRNA 1 (PRNCR1, rs16901946 G/A, rs13252298 G/A, rs1016343 T/C, and rs1456315 G/A) SNPs were in association with cancer risk. No association was found between the PRNCR1 (rs7007694 C/T) SNP and the risk of cancer. In conclusion, our results suggest that several studied lncRNA SNPs are associated with overall cancer risk. Therefore, they might be potential predictive biomarkers for the risk of cancer. More studies based on larger sample sizes and more lncRNA SNPs are warranted to confirm these findings.
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PMID:Association between long non-coding RNA polymorphisms and cancer risk: a meta-analysis. 2980 54

The tumor suppressor p16Ink4a, encoded by the INK4a gene, is an inhibitor of cyclin D-dependent kinases 4 and 6, CDK4 and CDK6. This inhibition prevents the phosphorylation of the retinoblastoma protein (pRb), resulting in cellular senescence through inhibition of E2F-mediated transcription of S phase genes required for cell proliferation. The p16Ink4a plays an important role in tumor suppression, whereby its deletion, mutation, or epigenetic silencing is a frequently observed genetic alteration in prostate cancer. To assess its roles and related molecular mechanisms in prostate cancer initiation and progression, we generated a mouse model with conditional deletion of p16Ink4a in prostatic luminal epithelium. The mice underwent oncogenic transformation and developed prostatic intraepithelial neoplasia (PIN) from eight months of age, but failed to develop prostatic tumors. Given the prevalence of aberrant androgen signaling pathways in prostate cancer initiation and progression, we then generated R26hARL/wt:p16L/L: PB-Cre4 compound mice, in which conditional expression of the human AR transgene and deletion of p16Ink4a co-occur in prostatic luminal epithelial cells. While R26hARL/wt:PB-Cre4 mice showed no visible pathological changes, R26hARL/wt:p16L/L: PB-Cre4 compound mice displayed an early onset of high-grade PIN (HGPIN), prostatic carcinoma, and metastatic lesions. Strikingly, we observed tumors resembling human sarcomatoid carcinoma with intermixed focal regions of signet ring cell carcinoma (SRCC) in the prostates of the compound mice. Further characterization of these tumors showed they were of luminal epithelial cell origin, and featured characteristics of epithelial to mesenchymal transition (EMT) with enhanced proliferative and invasive capabilities. Our results not only implicate a biological role for AR expression and p16Ink4a deletion in the pathogenesis of prostatic SRCC, but also provide a new and unique genetically engineered mouse (GEM) model for investigating the molecular mechanisms for SRCC development.
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PMID:Deletion of the p16INK4a tumor suppressor and expression of the androgen receptor induce sarcomatoid carcinomas with signet ring cells in the mouse prostate. 3067 79

Prostate cancer (PCa) is characterized by a unique dependence on optimal androgen receptor (AR) activity where physiological androgen concentrations induce proliferation but castrate and supraphysiological levels suppress growth. This feature has been exploited in bipolar androgen therapy (BAT) for castrate resistant malignancies. Here, we investigated the role of the tumor suppressor protein p14ARF in maintaining optimal AR activity and the function of the AR itself in regulating p14ARF levels. We used a tumor tissue array of differing stages and grades to define the relationships between these components and identified a strong positive correlation between p14ARF and AR expression. Mechanistic studies utilizing CWR22 xenograft and cell culture models revealed that a decrease in AR reduced p14ARF expression and deregulated E2F factors, which are linked to p14ARF and AR regulation. Chromatin immunoprecipitation studies identified AR binding sites upstream of p14ARF. p14ARF depletion enhanced AR-dependent PSA and TMPRSS2 transcription, hence p14ARF constrains AR activity. However, p14ARF depletion ultimately results in apoptosis. In PCa cells, AR co-ops p14ARF as part of a feedback mechanism to ensure optimal AR activity for maximal prostate cancer cell survival and proliferation.
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PMID:The p14ARF tumor suppressor restrains androgen receptor activity and prevents apoptosis in prostate cancer cells. 3233 May 14


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