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Supplementary Table 1 from Molecular Profiling Uncovers a p53-Associated Role for MicroRNA-31 in Inhibiting the Proliferation of Serous Ovarian Carcinomas and Other Cancers

Supplementary Table 2 from Molecular Profiling Uncovers a p53-Associated Role for MicroRNA-31 in Inhibiting the Proliferation of Serous Ovarian Carcinomas and Other Cancers

Supplementary Table 4 from Molecular Profiling Uncovers a p53-Associated Role for MicroRNA-31 in Inhibiting the Proliferation of Serous Ovarian Carcinomas and Other Cancers

Supplementary Table Legends 1-4 from Molecular Profiling Uncovers a p53-Associated Role for MicroRNA-31 in Inhibiting the Proliferation of Serous Ovarian Carcinomas and Other Cancers

Supplementary Table 3 from Molecular Profiling Uncovers a p53-Associated Role for MicroRNA-31 in Inhibiting the Proliferation of Serous Ovarian Carcinomas and Other Cancers

Background The biguanide metformin has been shown to not only reduce circulating glucose levels but also suppress in vitro and in vivo growth of prostate cancer. However, the mechanisms underlying the anti-tumor effects of metformin in advanced prostate cancers are not fully understood. The goal of the present study was to define the signaling pathways regulated by metformin in androgen-receptor (AR) positive, castration-resistant prostate cancers. Methods Our group used RNA sequencing (RNA-seq) to examine genes regulated by metformin within the C4–2 human prostate cancer cell line. Western blot analysis and quantitative RT-PCR were used to confirm alterations in gene expression and further explore regulation of protein expression by metformin. Results Data from the RNA-seq analysis revealed that metformin alters the expression of genes products involved in metabolic pathways, the spliceosome, RNA transport, and protein processing within the endoplasmic reticulum. Gene products involved in ErbB, insulin, mTOR, TGF-β, MAPK, and Wnt signaling pathways are also regulated by metformin. A subset of metformin-regulated gene products were genes known to be direct transcriptional targets of p53 or AR. Western blot analyses and quantitative RT-PCR indicated these alterations in gene expression are due in part to metformin-induced reductions in AR mRNA and protein levels. Conclusions Together, our results suggest metformin regulates multiple pathways linked to tumor growth and progression within advanced prostate cancer cells.

Mounting evidence is revealing a granularity within gene regulation that occurs at the level of mRNA translation. Within mammalian cells, canonical cap-dependent mRNA translation is dependent upon the interaction between the m7G cap-binding protein eukaryotic initiation factor 4E (eIF4E) and the scaffolding protein eukaryotic initiation factor 4G (eIF4G), the latter of which facilitates pre-translation initiation complex assembly, mRNA circularization, and ultimately ribosomal scanning. In breast epithelial cells, we previously demonstrated that the CELF1 RNA-binding protein promotes the translation of epithelial to mesenchymal transition (EMT) effector mRNAs containing GU-rich elements (GREs) within their 3’ untranslated regions (UTRs). Here we show that within this context, CELF1 directly binds to both the eIF4E cap-binding protein and Poly(A) binding protein (PABP), promoting translation of GRE-containing mRNAs in mesenchymal cells. Disruption of this CELF1/eIF4E interaction inhibits both EMT induction and experimental metastasis. Our findings illustrate a novel way in which non-canonical mechanisms of translation initiation underlie transitional cellular states within the context of development or human disease.

Nuclear receptors are a superfamily of ligand-activated transcription factors that play critical roles in the regulation of normal biological processes and several disease states. Of the nuclear receptors expressed within the prostate, the androgen receptor (AR) promotes the differentiation of prostatic epithelial cells and stimulates production of enzymes needed for liquefaction of semen. Multiple forms of AR also promote the growth of both early and late stage prostate cancers. As a result, drugs that target the AR signaling pathway are routinely used to treat patients with advanced forms of prostate cancer. Data also suggest that a second member of the nuclear receptor superfamily, the peroxisome proliferator activated receptor gamma (PPARγ), is a tumor suppressor that regulates growth of normal prostate and prostate cancers. Recent studies indicate there is a bidirectional interaction between AR and PPARγ, with each receptor influencing the expression and/or activity of the other within prostatic tissues. In this review, we examine how AR and PPARγeach regulate the growth and development of normal prostatic epithelial cells and prostate cancers. We also discuss interactions between the AR and PPARγsignaling pathways and how those interactions may influence prostate biology.

MicroRNAs (miRNAs) are small noncoding RNAs that direct gene regulation through translational repression and degradation of complementary mRNA. Although miRNAs have been implicated as oncogenes and tumor suppressors in a variety of human cancers, functional roles for individual miRNAs have not been described in clear cell ovarian carcinoma, an aggressive and chemoresistant subtype of ovarian cancer. We performed deep sequencing to comprehensively profile miRNA expression in 10 human clear cell ovarian cancer cell lines compared with normal ovarian surface epithelial cultures and discovered 54 miRNAs that were aberrantly expressed. Because of the critical roles of the phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene homolog 1/mammalian target of rapamycin (mTOR) pathway in clear cell ovarian cancer, we focused on mir-100, a putative tumor suppressor that was the most down-regulated miRNA in our cancer cell lines, and its up-regulated target, FRAP1/mTOR. Overexpression of mir-100 inhibited mTOR signaling and enhanced sensitivity to the rapamycin analog RAD001 (everolimus), confirming the key relationship between mir-100 and the mTOR pathway. Furthermore, overexpression of the putative tumor suppressor mir-22 repressed the EVI1 oncogene, which is known to suppress apoptosis by stimulating phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene homolog 1 signaling. In addition to these specific effects, reversing the expression of mir-22 and the putative oncogene mir-182 had widespread effects on target and nontarget gene populations that ultimately caused a global shift in the cancer gene signature toward a more normal state. Our experiments have revealed strong candidate miRNAs and their target genes that may contribute to the pathogenesis of clear cell ovarian cancer, thereby highlighting alternative therapeutic strategies for the treatment of this deadly cancer.

The peroxisome proliferator activated receptor gamma (PPARγ) is a ligand‐activated transcription factor that regulates growth and differentiation within normal prostate and prostate cancers. However the factors that control PPARγ within the prostate cancers have not been characterized. The goal of this study was to examine whether the androgen receptor (AR) regulates PPARγ expression and function within human prostate cancer cells. qRT‐PCR and Western blot analyses revealed nanomolar concentrations of the AR agonist dihydrotestosterone (DHT) decrease PPARγ mRNA and protein within the castration‐resistant, AR‐positive C4‐2 and VCaP human prostate cancer cell lines. The AR antagonists bicalutamide and enzalutamide blocked the ability of DHT to reduce PPARγ levels. In addition, siRNA mediated knockdown of AR increased PPARγ protein levels and ligand‐induced PPARγ transcriptional activity within the C4‐2 cell line. Furthermore, proteasome inhibitors that interfere with AR function increased the level of basal PPARγ and prevented the DHT‐mediated suppression of PPARγ. These data suggest that AR normally functions to suppress PPARγ expression within AR‐positive prostate cancer cells. To determine whether increases in AR protein would influence PPARγ expression and activity, we used lipofectamine‐based transfections to overexpress AR within the AR‐null PC‐3 cells. The addition of AR to PC‐3 cells did not significantly alter PPARγ protein levels. However, the ability of the PPARγ ligand rosiglitazone to induce activation of a PPARγ‐driven luciferase reporter and induce expression of FABP4 was suppressed in AR‐positive PC‐3 cells. Together, these data indicate AR serves as a key modulator of PPARγ expression and function within prostate tumors. J. Cell. Physiol. 231: 2664–2672, 2016. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

MicroRNAs (miRNA) regulate complex patterns of gene expression, and the relevance of altered miRNA expression to ovarian cancer remains to be elucidated. By comprehensively profiling expression of miRNAs and mRNAs in serous ovarian tumors and cell lines and normal ovarian surface epithelium, we identified hundreds of potential miRNA-mRNA targeting associations underlying cancer. Functional overexpression of miR-31, the most underexpressed miRNA in serous ovarian cancer, repressed predicted miR-31 gene targets including the cell cycle regulator E2F2. MIR31 and CDKN2A, which encode p14ARF and p16INK4A, are located at 9p21.3, a genomic region commonly deleted in ovarian and other cancers. p14ARF promotes p53 activity, and E2F2 overexpression in p53 wild-type cells normally leads via p14ARF to an induction of p53-dependent apoptosis. In a number of serous cancer cell lines with a dysfunctional p53 pathway (i.e., OVCAR8, OVCA433, and SKOV3), miR-31 overexpression inhibited proliferation and induced apoptosis; however, in other lines (i.e., HEY and OVSAYO) with functional p53, miR-31 had no effect. Additionally, the osteosarcoma cell line U2OS and the prostate cancer cell line PC3 (p14ARF-deficient and p53-deficient, respectively) were also sensitive to miR-31. Furthermore, miR-31 overexpression induced a global gene expression pattern in OVCAR8 associated with better prognosis in tumors from patients with advanced stage serous ovarian cancer, potentially affecting many genes underlying disease progression. Our findings reveal that loss of miR-31 is associated with defects in the p53 pathway and functions in serous ovarian cancer and other cancers, suggesting that patients with cancers deficient in p53 activity might benefit from therapeutic delivery of miR-31. Cancer Res; 70(5); 1906–15

The peroxisome proliferator activated receptor gamma (PPARγ) is a ligand-activated transcription factor that regulates in vitro and in vivo growth of castration-resistant human prostate cancer (PCa) cells. However, the factors that control expression of PPARγ within human PCa have not been characterized. We have previously shown that the androgen dihydrotestosterone decreases PPARγ levels and transcriptional activity in human PCa cells. Dihydrotestosterone serves as a high affinity ligand for the 110 kD form of the androgen receptor (AR-FL). Recent studies have shown the development of castration-resistant forms of prostate cancer is not only due to reactivation of AR-FL but also results from the expression of androgen receptor splice variants (ARVs) that lack the ligand-binding domain of the receptor. The goal of this study is to define the extent to which AR-FL and an ARV found in castration-resistant prostate cancer, AR-V7, regulate PPARγ expression and function. We first examined the role of AR-FL in the AR-positive C4-2 cell line. siRNA-mediated knockdown of endogenous AR-FL within C4-2 cells increased PPARγ protein and transcriptional activity. We next used reporter assays to further define the role of AR-FL and AR-V7 in PPARγ function. In these experiments, we first transfected plasmid vectors that express the AR-V7 or AR-FL into the AR null PC-3 prostate cancer cell line. A luciferase-based reporter assay was then used to measure alterations in PPARγ transcriptional activity within transfected cells. The addition of AR-FL to PC-3 cells resulted in reduced basal PPARγ luciferase activity. The ability of the ligand rosiglitazone to increase PPARγ activation was also suppressed in AR-FL positive PC-3 cells. A comparable decrease in ligand-induced PPARγ activation was detected in PC-3 cells that expressed AR-V7. The reduction in PPARγ activity produced by AR-FL and AR-V7 was likely not due to alterations in PPAR gamma expression, for we did not detect a consistent reduction in PPARγ mRNA and protein in transfected cells. Overall these data suggest that both AR-FL and AR-V7 are negative regulators of PPARγ function. Moreover, the AR-V7 stimulated reduction in PPARγ activity does not require the presence of AR-FL. Studies currently are underway to define the effect of endogenous AR-V7 on PPARγ expression and activity. This project was supported by NIGMS RISE grant (2R25GM059994-13), a NCI Mentored Career Development Award (K01CA114253), and the Vanderbilt CTSA grant UL1 RR024975-01 from NCRR/NIH. Citation Format: Emuejevoke Olokpa, Lamonica V. Stewart. PPARγ function is attenuated by full length androgen receptor and the AR-V7 variant in human prostate cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1848. doi:10.1158/1538-7445.AM2015-1848