Expression levels of retinoic acid receptor gamma (NR1B3/RARG, encodes RARγ) are commonly reduced in prostate cancer (PCa). Therefore, we sought to establish the cellular and gene regulatory consequences of reduced RARγ expression, and determine RARγ regulatory mechanisms. RARG shRNA approaches in non-malignant (RWPE-1 and HPr1-AR) and malignant (LNCaP) prostate models revealed that reducing RARγ levels, rather than adding exogenous retinoid ligand, had the greatest impact on prostate cell viability and gene expression. ChIP-Seq defined the RARγ cistrome, which was significantly enriched at active enhancers associated with AR binding sites. Reflecting a significant genomic role for RARγ to regulate androgen signaling, RARγ knockdown in HPr1-AR cells significantly regulated the magnitude of the AR transcriptome. RARγ downregulation was explained by increased miR-96 in PCa cell and mouse models, and TCGA PCa cohorts. Biochemical approaches confirmed that miR-96 directly regulated RARγ expression and function. Capture of the miR-96 targetome by biotin-miR-96 identified that RARγ and a number of RARγ interacting co-factors including TACC1 were all targeted by miR-96, and expression of these genes were prominently altered, positively and negatively, in the TCGA-PRAD cohort. Differential gene expression analyses between tumors in the TCGA-PRAD cohort with lower quartile expression levels of RARG and TACC1 and upper quartile miR-96, compared to the reverse, identified a gene network including several RARγ target genes (e.g., SOX15) that significantly associated with worse disease-free survival (hazard ratio 2.23, 95% CI 1.58 to 2.88, p = 0.015). In summary, miR-96 targets a RARγ network to govern AR signaling, PCa progression and disease outcome.

中文翻译：

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miR-96和RARγ信号轴控制雄激素信号和前列腺癌的进展。

维甲酸受体γ（NR1B3 / RARG，编码RARγ）的表达水平通常在前列腺癌（PCa）中降低。因此，我们寻求建立减少RARγ表达的细胞和基因调控结果，并确定RARγ调控机制。在非恶性（RWPE-1和HPr1-AR）和恶性（LNCaP）前列腺模型中的RARG shRNA方法显示，降低RARγ水平而不是添加外源类维生素A配体对前列腺细胞生存力和基因表达影响最大。ChIP-Seq定义了RARγ病，该病在与AR结合位点相关的活性增强子上显着富集。反映RARγ调节雄激素信号的重要基因组作用，HPr1-AR细胞中的RARγ敲低显着调节了AR转录组的大小。在PCa细胞和小鼠模型以及TCGA PCa队列中，miR-96的增加解释了RARγ的下调。生化方法证实了miR-96直接调节RARγ的表达和功能。生物素-miR-96对miR-96靶基因组的捕获表明，miR-96靶向RARγ和包括TACC1在内的许多RARγ相互作用辅因子，并且这些基因的表达在正向和负向显着改变。 TCGA-PRAD队列。与反向比较，在具有较低RARG和TACC1四分位数表达水平和较高miR-96四分位数表达水平的TCGA-PRAD队列中的肿瘤之间的差异基因表达分析确定了一个包含多个RARγ靶基因（例如SOX15）的显着相关的基因网络无病生存期较差（危险比2.23，95％CI为1.58至2.88，p = 0.015）。总之，