Class I histone deacetylases (HDACs) have been reported to be overexpressed in clear cell renal cell carcinoma (ccRCC), whereas the expression of class II HDACs is unknown. Four isogenic cell lines C2/C2VHL and 786-O/786-OVHL with differential VHL expression are used in our studies. Cobalt chloride is used to mimic hypoxia in vitro. HIF-2α knockdowns in C2 and 786-O cells is used to evaluate the effect on HDAC 1 expression and activity. Invasion and migration assays are used to investigate the role of HDAC 1 and HDAC 6 expression in ccRCC cells. Comparisons are made between experimental groups using the paired T-test, the two-sample Student’s T-test or one-way ANOVA, as appropriate. ccRCC and the TCGA dataset are used to observe the clinical correlation between HDAC 1 and HDAC 6 overexpression and overall and progression free survival. Our analysis of tumor and matched non-tumor tissues from radical nephrectomies showed overexpression of class I and II HDACs (HDAC6 only in a subset of patients). In vitro, both HDAC1 and HDAC6 over-expression increased cell invasion and motility, respectively, in ccRCC cells. HDAC1 regulated invasiveness by increasing matrix metalloproteinase (MMP) expression. Furthermore, hypoxia stimulation in VHL-reconstituted cell lines increased HIF isoforms and HDAC1 expression. Presence of hypoxia response elements in the HDAC1 promoter along with chromatin immunoprecipitation data suggests that HIF-2α is a transcriptional regulator of HDAC1 gene. Conversely, HDAC6 and estrogen receptor alpha (ERα) were co-localized in cytoplasm of ccRCC cells and HDAC6 enhanced cell motility by decreasing acetylated α-tubulin expression, and this biological effect was attenuated by either biochemical or pharmacological inhibition. Finally, analysis of human ccRCC specimens revealed positive correlation between HIF isoforms and HDAC. HDAC1 mRNA upregulation was associated with worse overall survival in the TCGA dataset. Taking together, these results suggest that HDAC1 and HDAC6 may play a role in ccRCC biology and could represent rational therapeutic targets.

BACKGROUND: Currently, limited mouse models that mimic the clinical course of castrate resistant prostate development currently exist. Such mouse models are urgently required to conduct pre‐clinical studies to assist in the understanding of disease progression and the development of rational therapeutic strategies to treat castrate resistant prostate cancer.METHODS: Wild type intact FVB male mice were injected by subcutaneous injection with Myc‐CaP cells to establish androgen sensitive Myc‐CaP tumors. Tumor bearing mice were castrated and resulting tumors serially passaged in pre‐castrated FVB male mice to produce a bone fide Myc‐CaP castrate resistant tumor.RESULTS: Immunohistochemical analysis revealed that initial androgen sensitive Myc‐CaP tumors had strong nuclear transcriptional active androgen receptor expression, as indicated by marked c‐MYC staining and were highly proliferative. Castration of tumor bearing animals resulted in cytoplasmic relocation of androgen receptor concurrent with loss of transcriptional activity and tumor proliferation. Serial passaging of castrate refractory Myc‐CaP in pre‐castrated male FVB mice resulted in the development of a bona fide castrate resistant Myc‐CaP tumor which pheno‐copied the original androgen sensitive parental Myc‐CaP tumor.CONCLUSIONS: Developing a murine castrate transplant resistant tumor model that mimics the clinical course of human castrate resistant prostate cancer will create better opportunities to understand the development of castrate resistant prostate cancer and also allow for more rapid pre‐clinical studies to stratify rational novel therapies for this lethal form of prostate cancer. Prostate 72:587–591, 2012.

Stromal antigen 2 (STAG2), in healthy somatic cells, functions in sister chromatid cohesion, DNA damage repair, and genome organization, but its role in muscle-invasive bladder cancer (MIBC) remains unknown. Here, using whole-exome and targeted sequencing (n = 119 bladder cancer clinical samples), we found several STAG2 mutations in MIBC that correlate with loss of protein expression. The analysis of a bladder cancer tissue microarray (n = 346) revealed that decreased STAG2 protein expression is associated with improved overall and progression-free survival for patients with MIBC. In mouse xenograft studies, STAG2 knockdown (KD) decelerated MIBC tumor growth, whereas STAG2 overexpression accelerated tumor growth. In cell line studies, STAG2 loss augmented treatment with cisplatin, a first-line therapy for MIBC. STAG2 KD or overexpression did not alter degree of aneuploidy, copy-number variations, or cell-cycle distribution. However, unbiased RNA-sequencing analysis revealed that STAG2 KD altered gene expression. STAG2 KD led to significant downregulation of several gene sets, such as collagen containing extracellular matrix, external encapsulating structure organization, and regulation of chemotaxis. Therefore, we investigated the effect of STAG2 KD on cell migration and invasion in vitro. We found that STAG2 KD minimized cell speed, displacement, and invasion. Altogether, our results present a noncanonical function of STAG2 in promoting cell motility and invasion of MIBC cells. This work forms the basis for additional investigation into the role of STAG2 in transcriptional regulation and how it becomes dysregulated in STAG2-mutant MIBC.Significance: The cohesin component STAG2 regulates cell motility and invasion. STAG2 expression is associated with decreased MIBC survival and may be a useful biomarker to guide bladder cancer treatment.

Dihydrotestosterone (DHT) and testosterone (T), which mediate androgen receptor nuclear translocation and target gene transcription, are crucial androgens and essential molecular triggers required for the proliferation and survival of prostate cancer cells. Therefore, androgen metabolism is commonly targeted in the treatment of prostate cancer. Using a high-pressure liquid chromatographic assay with tandem mass spectral detection, we determined the serum levels of metabolites produced during DHT/T biosynthesis in African American (AA) and European American (EA) men with localized, therapy naïve prostate cancer. Serum progesterone and related metabolites were significantly lower in AA men than in EA men, and these differences were associated with rapid disease progression. Multivariate analysis revealed significant differences between a subset of intermediate androgen metabolites between AA and EA men and between men with <=3 + 4 and >=4 + 3 Gleason score disease. AA men have a significantly higher frequency of single nucleotide polymorphisms in CYP11B1 and CYP11B2, enzymes that regulate corticosterone-aldosterone conversion. Finally, higher levels of T and pregnenolone were associated with a lower risk of progression-free survival only in AA men. This work provides new insight into androgen metabolism and racial disparities in prostate cancer by presenting evidence of dysregulated androgen biosynthesis in therapy naïve disease that correlates with clinical variables.

Authors: Xuan Peng1, Eduardo Cortes Gomez1, Kristopher Attwood1, Ivan V. Maly2, Wilma A. Hofmann2, Wendy Huss1, Gissou Azabdaftari1, Li Yan1, Jianmin Wang1, and Anna Woloszynska1 Affiliations: 1Roswell Park Comprehensive Cancer Center, 2Jacobs School of Medicine and Biomedical Sciences Abstract Body: "African American (AA) men are often diagnosed with aggressive

Dihydrotestosterone (DHT) and testosterone (T) mediated androgen receptor (AR) nuclear translocation initiates transcription of AR target genes that are pivotal for prostate cancer (PrCa) development and progression. Here we provide data indicating that in contrast to European American (EA) men, African American (AA) men with localized PrCa can exploit an alternative progesterone-androsterone-5α-androstanedione pathway for DHT biosynthesis. Enzymes that are involved in alternate pathways of DHT biosynthesis are elevated in PrCa tissues from AA men, compared to EA men, and also correlated with increased serum DHT levels. In addition, higher serum DHT levels reflect increased RNA expression of AR target genes in PrCa tissues from AA men. Interestingly, serum T but not DHT levels are significantly lower in AA men compared to EA men with PrCa. Furthermore, serum progesterone and related intermediate metabolites levels that are produced during alternate pathways of DHT biosynthesis are significantly lower in AA men with PrCa and associated with a shorter time to disease progression. These data highlight that androgen biosynthesis is altered in therapy naïve localized PrCa in AA men, and can potentially serve as prognostic indicators of disease progression. Significance Our work provides a rationale to examine potential pharmacological interventions that target androgen biosynthesis and AR signaling earlier in the disease continuum in AA men with PrCa. Additionally, our study lays the groundwork for developing serum measurements of intermediate androgen metabolites as PrCa prognostic biomarkers.