增强的雌激素效应通过启动EMT程序诱导良性前列腺增生的作用及其分子机制的研究

The enhanced estrogenic effect is an important predisposing factor of BPH. The applicants have long been engaged in studying the role of estrogen actions in the etiology of BPH. Recently, we noticed that there are some cellular clusters budding towards the stroma from the basal layer in human BPH tissues, and there are also a few cellular clusters cresting towards the inner side of acinis from the luminal layer. The cells in these clusters lost the expression of their epithelial specific marker, E-cadherin, but express the mesenchymal cell marker, Vimentin. The epithelial-mensenchymal transition (EMT) related transcription factor Twist, the stemness cell and de-differentiation marker, SMemb, are also expressing in these cell. We have successfully established testosterone/estradiol induced rat BPH model. We observed that in the early stage of the development of hyperplasia, the eplthelial cells expressed a great amount of estrogen receptor alpha, SMemb and Vimentin. Laser Capture Microdissection (LCM)/Microarray techniques was used to analyze the gene expression profiles in prostate epithelial cells during the progression of BPH. The results show that in the early stage of the BPH development, the stemness cell marker and the genes related to EMT/MET are apparently up-regulated in epithelial cells. Based on our previous study, herein we make the hypothesis that "The enhanced estrogenic effects activate the stemness cells and initiate the EMT program similar to that in embryonic development, which plays critical roles in the pathogenesis of BPH". In this project, we will study the role of estrogen in activating stemness cell and promoting the EMT progress, and clarify the mechanism underlying these effects. The achievements of this study will provide novel annotation of the pathogenesis of BPH, and generate an enormous improvement in the management of this disorder.

雌激素效应增强是前列腺增生（BPH）发生的重要诱因。申请人长期从事雌激素效应在BPH中作用机制研究。近期发现，人BPH组织中发生病理改变的上皮细胞失去了上皮细胞特异的E-Cadherin，表达间质细胞标记分子Vimentin、EMT转录因子Twist和干性细胞以及去分化标记分子SMemb。在雌/雄激素诱导大鼠增生早期前列腺上皮细胞中表达大量雌激素受体α、SMemb和Vimentin。激光显微切割联合表达谱芯片分析大鼠上皮细胞中表达的差异基因发现，干性细胞标记分子和与EMT/MET相关基因明显上调。据此提出"增强的雌激素效应通过使基底层中干性细胞去分化启动前列腺胚胎发育中EMT程序，改变了上皮与间质细胞相互作用，诱导了组织重构性的前列腺增生"的研究假说。本项目将证实这个研究假说，阐明雌激素在激活干性细胞和促进EMT中的作用及其分子机制。其研究成果将对BPH发生机制和转归提供新的诠释和途径。

良性前列腺增生症（BPH）是中老年男性泌尿外科的常见疾病。上皮-间质转化（Epithelial-to-mesenchymal transition，EMT）参与了多种疾病的发生和发展。本项目在前期研究工作中发现BPH组织中存在EMT，而且BPH中发生的EMT可能与雌激素效应有关的基础上，通过体外三维细胞技术进一步研究雌二醇是否能够促进人良性前列腺上皮细胞发生EMT及其作用的分子机制。研究发现，雌二醇在雌激素受体α（ERα）的介导下通过激活基底和鲁米诺细胞中干性细胞的转分化使前列腺上皮细胞发生EMT；而且发生EMT的细胞表型为表达细胞角蛋白CK17的中间态细胞。生物信息学分析发现，雌雄激素诱导的大鼠良性前列腺增生组织中与Wnt通路相关的基因表达增加。免疫组化实验结果显示，人良性前列腺增生组织发生EMT的细胞存在着β-catenin入核的现象；雌二醇处理体外前列腺上皮细胞中亦出现β-catenin入核的细胞数目增加。提示，发生EMT的细胞伴随着Wnt信号通路的激活。这些研究成果部分阐明了雌激素效应在BPH发生发展过程中的作用机制，为开发临床治疗BPH的药物提供了新的理论基础。