前列腺癌中AMACR高表达的转录和转录后调控机制及其生物学功能的研究

Prostate cancer is one of the most common malignant tumors of the male urogenital system. AMACR/P504S (alpha-methylacyl-CoA racemase) is a sensitive and specific marker for the diagnosis of prostate cancer. But it is not clear why it is overexpressed in prostate cancer up to now. In this project, we propose several hypotheses for the up-regulation of AMACR in prostate cancer on the basis of literature review, bioinformatics analysis and our preliminary experiments: (1) the transcription of AMACR is directly regulated by a group of activated transcription factors (HIF-1a，ETS1，STAT，SP1,etc);(2) some deletion hotspots in AMACR promoter CpG island are putative cis-regulatory elements for some inactivated or dysfunctional transcription factors (NKX3.1, AP2, TP53, PAX6, C/EBP,etc);(3)a group of miRNAs(miR-200c, miR-200b, miR-429, miR-1197,etc) bind to the 3'-UTR binding site of AMACR and play a negative post-transcriptional regulatory function. AMACR plays an important biological function in prostate cancer and participates in androgen receptor signaling pathway either in a direct or indirect way. We will test these hypotheses by experimental work in this project.

前列腺癌是男性泌尿生殖系统最常见的恶性肿瘤之一。AMACR/P504S是前列腺癌敏感而特异的诊断标记之一，但其在前列腺癌中高表达的机制不明。本课题通过广泛文献复习结合生物信息学分析及本课题组前期实验结果提出前列腺癌中AMACR高表达的可能机制：（1）直接调控AMACR启动子序列的转录因子（HIF-1a、ETS1、STAT、SP1等）活化；（2）AMACR启动子序列CpG热点缺失或其他序列异常影响表达下调或功能缺陷的转录因子（NKX3.1、AP2、TP53、PAX6、C/EBP等）结合；（3）微小RNA（miR-200c, miR-200b, miR-429, miR-1197等）与AMACR 3'-UTR区相互作用，对其进行转录后负调控。AMACR在前列腺癌中发挥重要生物学功能。AMACR直接或间接参与雄激素受体信号通路。课题拟通过多种实验方法对以上假说进行验证。

AMACR/P504S是前列腺癌敏感而特异的诊断标记之一，但其在前列腺癌中高表达的机制不明。本课题通过广泛文献复习结合生物信息学分析及本课题组前期实验结果提出前列腺癌中AMACR高表达的可能机制：（1）直接调控AMACR启动子序列的转录因子（HIF-1a、ETS1、STAT、SP1等）活化；（2）AMACR启动子序列CpG热点缺失或其他序列异常影响表达下调或功能缺陷的转录因子（NKX3.1、AP2、TP53、PAX6、C/EBP等）结合；（3）微小RNA（miR200c, miR200b, miR429, miR1197等）与AMACR 3'-UTR区相互作用，对其进行转录后负调控。后续研究发现，良性前列腺组织及前列腺癌细胞株中miR200c与AMACR的表达呈负相关，腺病毒载体人工过表达miR200c后，AMACR表达明显下调。双荧光素酶报告基因系统证实miR200c直接结合AMACR 3’-UTR区90-97nt序列，负调控AMACR的表达。腺病毒过表达miR200c或siRNA下调AMACR的表达均可导致前列腺癌PC-3和Du145细胞生长减慢，迁移和侵袭能力下降；且人工过表达AMACR可逆转腺病毒过表达miR200c所导致的生物学效应。进一步探讨前列腺癌中miR200c的上游靶分子，结果显示HIF-1a可通过结合miR200c启动子序列-425bp的HRE位点，直接靶向抑制miR200c的转录，HIF-1a-miR200c-AMACR通路异常可能是前列腺癌中AMACR高表达的重要原因。该课题深入研究了前列腺癌中AMACR高表达的转录和转录后调控机制，提出HIF-1a-miR200c-AMACR通路异常可能在前列腺癌发生发展过程中发挥重要作用，可能成为潜在的治疗靶点。