Regulation of Intratumor Androgen/Androgen Receptor signaling in Prostrate Cancer

前列腺癌管理的挑战源于1）无法区分惰性前列腺癌和 具有转移潜力的侵袭性恶性肿瘤; 2）复发性、去势抵抗的治疗选择有限 前列腺癌（CRPC）。CRPC中雄激素受体（AR）的再活化是由于表达升高和 AR的活性，并增加从DHEA的从头雄激素生物合成。抗AR/抗雄激素生物合成 药物抑制化疗后的癌症几个月，但反应不是普遍的。寻找新的预测因子 癌症进展和新的药物靶点是高度优先的目标。我们将研究一个新的方面， 雄激素激活的AR信号，这是从我们的研究揭示。这需要i）调节雄激素 通过前列腺表达的SULT 2B（一种介导胆固醇硫酸化的磺基转移酶）实现体内平衡 和DHEA，和ii）增强的甲基化AR活性。我们显示1）SULT 2B mRNA和蛋白水平是 在临床标本中显著降低，组织微阵列的IHC染色显示高度统计学意义 在癌组织中SULT 2B的显著（p<0.001）损失; 2）SULT 2B沉默引起癌细胞增殖增加， 前列腺癌细胞; 3）维生素D受体（VDR）和氧固醇诱导的肝X受体（LXR）可以 诱导SULT 2B基因（SULT 2B 1）; 4）AR在其铰链结构域中的赖氨酸残基处被 SET 9赖氨酸甲基转移酶。SET 9缺失降低野生型但不降低甲基化位点突变体的AR活性; 5)LSD 1是一种组蛋白赖氨酸脱甲基酶，可将甲基化AR转化为非甲基化AR; 6）LXR-<$是一种潜在的 编码SET 9和LSD 1的基因的调节子，因为LXR响应性顺式元件存在于这两个基因中。 基于计算机分析的基因。我们已经研制出一种抗体可以特异性识别赖氨酸- 通过蛋白质印迹法测定甲基化AR。我们假设晚期前列腺癌与减少的 SULT 2B和升高的甲基修饰的AR，LXR-1通过防止前列腺癌的丢失来部分抑制前列腺癌。 SULT 2B和甲基化AR的升高，以及VDR协同LXR效应。这个假设是建立在我们的 i）LXR- -/-小鼠在腹侧前列腺中显示出增强的雄激素敏感性， 但AR水平无变化; ii）对抗DHEA硫酸化的类固醇硫酸酯酶（Sts）在前列腺中诱导 iii）LXR抑制异种移植物中的前列腺癌; 肿瘤的我们建议确定：目的1）SULT 2B丢失在前列腺癌中的意义，以及DNA的作用 甲基化在这个过程中我们将检查i）不同标本中癌组织中低SULT 2B的相关性 i）DHT水平和AR靶基因表达，ii）酶AKR 1C 3和SRD 5A 1的水平，和iii） SULT 2B 1基因的甲基化状态。临床变量（包括种族的作用）与 将对上述参数进行研究。目的2）SULT 2B调节的雄激素对LXR信号转导的影响 前列腺内稳态、与VDR可能的协同作用及其在前列腺癌中的相关性。我们将调查 i）SULT 2B 1中的LXR响应性DNA顺式元件及其与LXR-、辅助调节子、染色质的相互作用 修饰剂; ii）LXR-与VDR在SULT 2B诱导和前列腺癌抑制中的协同作用; iii）LXR-与VDR在SULT 2B诱导和前列腺癌抑制中的DHT水平; LXR-沉默的前列腺癌细胞在体外和体内，并在LXR-无效的小鼠前列腺和逆转的前列腺癌细胞， 骨化三醇对LXR沉默的影响; iv）临床标本中低SULT 2B与减毒LXR之间的联系 LXR-和LXR-靶向脂肪生成基因的表达。目的3）前列腺组织中AR甲基化的意义 癌症及其与LXR的相互作用我们将检查i）LXR中甲基化AR水平- -敲低癌症 ii）LXR-在SET 9和LSD 1表达中的作用及其与AR的关联iii） 临床标本中甲基化AR水平升高（相对于总AR）。方法：免疫组化，组织芯片， LCM，蛋白质印迹，焦磷酸测序，硫酸氢盐修饰的DNA，启动子测定，ChIP，慢病毒，siRNA，LC- MS/MS分子生物学家，病理学家和生物统计学家将合作。将使用多个核心。 意义：这项研究可能揭示新的预测标志物和新的干预靶点，以预防CRPC。 .

Challenges in prostate cancer management stem from 1) inability to distinguish indolent prostate cancer from aggressive malignancy with metastatic potential; 2) limited treatment options for recurrent, castration-resistant prostate cancer (CRPC). Reactivated androgen receptor (AR) in CRPC results from elevated expression and activity of AR, and increased de novo androgen biosynthesis from DHEA. Anti-AR/anti-androgen biosynthesis drugs inhibit post chemotherapy cancer for a few months, but response is not universal. Finding new predictors for cancer progression and new drug targets are high-priority goals. We will examine a novel aspect of androgen-activated AR signaling that was revealed from our study. This entails i) regulation of androgen homeostasis by the prostate-expressed SULT2B, a sulfotransferase which mediates sulfation of cholesterol and DHEA, and ii) enhanced activity of methylated AR. We show 1) SULT2B mRNA and protein levels are markedly reduced in clinical specimens and IHC staining of tissue microarrays revealed highly statistically significant (p<0.001) loss of SULT2B in cancer tissue; 2) SULT2B silencing caused increased proliferation of prostate cancer cells; 3) Vitamin D receptor (VDR) and the oxysterol-inducible liver X receptor (LXR) can induce the SULT2B gene (SULT2B1); 4) AR is monomethylated at a lysine residue in its hinge domain by the SET9 lysine methyltransferase. SET9 depletion reduced wild type but not methylation-site-mutant AR activity; 5) LSD1, a histone lysine demethylase can convert methylated AR to unmethylated AR; 6) LXR-¿ is a potential regulator of genes encoding SET9 and LSD1, since LXR-responsive cis elements are present in these two genes based on in silico analysis. We have developed an antibody that can specifically recognize lysine- methylated AR by western blotting. We hypothesize that advanced prostate cancer associates with reduced SULT2B and elevated methyl-modified AR, LXR-¿ inhibits prostate cancer in part by preventing loss of SULT2B and elevation of methylated AR, and VDR synergizes LXR effects. The hypothesis is built from our own results and from reports that i) LXR- -/- mice show heightened androgen sensitivity in ventral prostates, but no change in AR levels; ii) steroid sulfatase (Sts) which counters DHEA sulfation, was induced in prostates of Lxr- -/- mice and suppressed in LXR- -activated mice; iii) LXR inhibited prostate cancer in xenograft tumors. We propose to determine: Aim 1) significance of SULT2B loss in prostate cancer, and a role for DNA methylation in this loss. We will examine i) diverse specimens for association of low SULT2B in cancer tissue with i) DHT levels and AR target gene expression, ii) levels of the enzymes AKR1C3 & SRD5A1, and iii) methylation status of the SULT2B1 gene. Statistical association of clinical variables (including role of race) with above parameters will be explored. Aim 2) the dynamics of LXR- signaling with SULT2B-regulated androgen homeostasis in prostate, possible synergy with VDR and their relevance in prostate cancer. We will investigate i) LXR-responsive DNA cis element(s) in SULT2B1 and its interaction with LXR- , coregulators, chromatin modifiers; ii) Synergy of LXR- with VDR in SULT2B induction and prostate cancer inhibition; iii) DHT levels in LXR- -silenced prostate cancer cells in vitro & in vivo, and in Lxr- -null mouse prostates and reversal of the effect of LXR silencing by calcitriol; iv) a link in clinical specimens between low SULT2B and attenuated expression of LXR- and LXR- -targeted lipogenic genes. Aim 3) significance of AR methylation in prostate cancer and its interplay with LXR-¿. We will examine i) methylated AR levels in LXR- -knocked down cancer cells in vitro & in vivo; ii) a role for LXR- in SET9 & LSD1 expression and in their association with AR iii) clinical specimens for elevated methylated AR levels (relative to total AR). Methods: IHC, tissue microarray, LCM, western blot, pyrosequencing, bisulfate-modified DNA, promoter assay, ChIP,, lentivirus, si RNAs, LC- MS/MS. Molecular biologists, pathologists and biostatisticians will collaborate. Multiple cores will be used. Significance: This study may reveal new predictive markers and new intervention targets to prevent CRPC. .