Androgen receptor mediates the expression of UDP-glucuronosyltransferase 2 B15 and B17 genes
Androgen receptor mediates the expression of UDP-glucuronosyltransferase 2 B15 and B17 genes
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DOI：
10.1002/pros.20749
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发表时间：
2008-06-01
期刊：
影响因子：
2.8
通讯作者：
Lee, Gwo-Shu Mary
中科院分区：
文献类型：
--
作者：
Bao, Bo-Ying;Chuang, Bin-Fay;Lee, Gwo-Shu Mary
背景。雄激素受体（AR）活性的增强可能在前列腺癌发展到去势抵抗状态中起重要作用。比较雄激素依赖性和非依赖性前列腺肿瘤的表达谱发现，雄激素分解代谢酶udp -葡萄糖醛酸糖基转移酶2B15 （UGT2B15）的表达显著增加。我们研究了UGT2B15和B17在雄激素治疗下差异表达的控制机制。方法。RT-PCR检测基因表达。采用染色质免疫沉淀法（CHIP）检测AR与UGT2B15/B17基因的相关性。采用RNA干扰法敲除基因表达。结果。UGT2B15和B17基因在AR阴性前列腺癌细胞系、PC3和DU145中不表达，而在AR阳性细胞系、LNCaP、LNCaP-abl（雄激素非依赖性LNCaP亚系）和VCaP中表达。与LNCaP相比，LNCaP-abl中UGT2B15/B17的表达水平上调。这些结果提示AR对UGT2B15/B17的表达是必需的。DHT处理后，LNCaP中UGT2B15/B17的表达呈时间和剂量依赖性下调，这种下调被氟他胺和比卡鲁胺竞争性拮抗，提示AR介导的通路。进一步的CHIP实验证实AR与UGT2B15/B17基因启动子区直接相互作用。在LNCaP中敲低AR表达可显著降低UGT2B15/B17的表达，完全抑制dht诱导的UGT2B15/B17基因下调。结论。我们证明了UGT2B15和B17是雄激素调节的主要基因，AR是其基础表达和雄激素调节表达所必需的。
BACKGROUND. Enhanced androgen receptor (AR) activity by increased testosterone availability may play important roles in prostate cancer progressing to castration resistant state. Comparison of expression profiles in androgen dependent and independent prostate tumors demonstrated a marked increase of the expression of UDP-glucuronosyltransferase 2B15 (UGT2B15), an androgen catabolic enzyme. We investigated mechanisms controlling the differential expression of UGT2B15 and B17 in response to androgen treatments. METHODS. Gene expression was determined by RT-PCR. The association of AR with UGT2B15/B17 genes was determined by Chromatin immuno-precipitation (CHIP). RNA interference was used to knock-down gene expression. RESULTS. UGT2B15 and B17 genes were not expressed in AR negative prostate cancer cell lines, PC3 and DU145, while they were expressed in AR positive cell lines, LNCaP, LNCaP-abl (an androgen independent LNCaP sub-line), and VCaP. The expression levels of UGT2B15/B17 were up-regulated in LNCaP-abl comparing to those in LNCaP. These results suggest the requirement of AR for the expression of UGT2B15/B17. Treatment with DHT down-regulated the expression of UGT2B15/B17 in LNCaP in a time and dose dependent manner and this down-regulation was competitively antagonized by flutamide and bicalutimide, suggesting a pathway mediated by AR. Further CHIP experiments demonstrated the direct interaction of AR with the promoter regions of UGT2B15/B17 genes. Knocking down AR expression in LNCaP significantly reduced the expression of UGT2B15/B17 and completely inhibited the DHT-induced down-regulation of UGT2B15/B17 genes. CONCLUSIONS. We demonstrated that UGT2B15 and B17 are primary androgen-regulated genes and AR is required for both their basal expression and their androgen-regulated expression.