Estrogen Receptors in Human Prostate Stem-Progenitor Cells

描述（由申请人提供）：前列腺是一种激素依赖性组织，在整个生命过程中受雄激素作用调节。还已知雌激素在前列腺发育和体内平衡中起关键作用，并有助于前列腺癌的发生和进展。虽然雌激素通过多种受体在女性器官中的作用已被详细研究，但对前列腺中雌激素作用的机制还不清楚。最近，我们的实验室证明，来自正常成人前列腺的人前列腺上皮干细胞和祖细胞表达强水平的雌激素受体- ER <$、ER <$和GPR 30-并表现出对雌二醇-17 <$的增殖反应增加。此外，初步数据表明，在人前列腺癌（PCa）干细胞样细胞中ER表达增加，表明这种小肿瘤细胞群可能是直接的雌激素靶点。拟议研究的总体目标是描述雌激素受体（ER <$、ER <$和GPR 30）在正常和癌变人前列腺上皮干细胞和祖细胞中的作用，并阐明其在促进或预防癌变和进展中的特定作用。为实现这些目标，提出了三个具体目标。目标1：明确ER <$、ER <$和GPR 30在调节来自正常成人组织的人前列腺干祖细胞的自我更新、扩增、凋亡和/或分化中的特定作用。为了实现这一点，我们将利用一个充分表征的前列腺系统，询问干细胞和祖细胞从原代前列腺上皮细胞培养的无病器官捐赠者。目的2：探讨特异性雌激素受体在人前列腺癌干细胞样细胞中的表达及作用。将使用患者标本中良性和PCa细胞的原代上皮培养物，通过前列腺球试验富集干细胞/祖细胞。结果将通过询问两种永生化人PCa干细胞样细胞系HPET和HuSLC中的ER作用来支持。与正常和癌症相关的成纤维细胞的共培养研究将用于定义正常和癌症人类前列腺中的雌激素响应性干细胞小生境。目的3：阐明特异性雌激素受体在体内介导激素致癌和调节前列腺癌生长和进展中的作用。已经使用与胚胎间充质混合的正常人前列腺干/祖细胞或人PCa干细胞样细胞建立了体内细胞重组移植模型，以产生具有正常人前列腺上皮或前列腺癌的嵌合前列腺样组织。将测试靶向ER敲除和选择性雌激素受体调节剂（SERM）以描述雌激素作用并调节体内PCa生长。总之，目前的方法将提供第一个直接的证据ER特异性的行动，在人类前列腺干细胞和祖细胞。重要的是，使用来自器官捐献者和PCa患者的新鲜人前列腺标本将使这些发现具有翻译相关性。由前列腺癌生长对SERM的体内反应支持的详细分子结果有可能确定用于管理PCa的新治疗靶点，并为未来使用靶向干细胞ER作用的新型小分子的药物发现策略提供信息。

DESCRIPTION (provided by applicant): The prostate gland is a hormone dependent tissue regulated throughout life by androgen action. It is also known that estrogens play key roles in prostate development and homeostasis and contribute to prostate carcinogenesis and progression. While estrogen actions through multiple receptors have been studied in detail in female organs, the mechanisms of estrogenic effects in the prostate gland are not well understood. Recently, our laboratory demonstrated that human prostate epithelial stem and progenitor cells from normal adult prostates express robust levels of estrogen receptors - ER¿, ER¿ and GPR30 - and exhibit increased proliferative responses to estradiol-17¿. Further, preliminary data indicate heightened ER expression in human prostate cancer (PCa) stem-like cells suggesting that this minor tumor cell population may be a direct estrogen target. The overall goal of the proposed studies is to delineate the roles of estrogen receptors (ER¿, ER¿ and GPR30) in epithelial stem and progenitor cells of the normal and cancerous human prostate gland and to elucidate their specific roles in promoting or preventing carcinogenesis and progression. Three Specific Aims are proposed to accomplish these goals. AIM 1: Define the specific roles for ER¿, ER¿ and GPR30 in regulating self-renewal, amplification, apoptosis and/or differentiation in human prostate stem- progenitor cells from normal adult tissues. To accomplish this, we will utilize a fully characterized prostasphere system to interrogate stem and progenitor cells from primary prostate epithelial cultures of disease-free organ donors. AIM 2: Elucidate the expression and roles of specific ERs in human prostate cancer stem-like cells. Primary epithelial cultures of benign and PCa cells from patient specimens will be utilized to enrich for stem/progenitor cells by prostasphere assay. Results will be supported by interrogating ER actions in two immortalized human PCa stem-like cell lines, HPET and HuSLC. Co-culture studies with normal and cancer- associated fibroblasts will be used to define the estrogen-responsive stem cell niche in normal and cancerous human prostates. AIM 3: Delineate the actions of specific ERs in mediating hormonal carcinogenesis in vivo and regulating PCa growth and progression. An in vivo cell recombination graft model has been established using normal human prostate stem/progenitor cells or human PCa stem-like cells mixed with embryonic mesenchyme to generate chimeric prostate-like tissues with normal human prostate epithelium or prostate cancer. Targeted ER knockdown and selective estrogen receptor modulators (SERMs) will be tested to delineate estrogen actions and regulate PCa growth in vivo. Together, the present approaches will provide the first direct evidence for ER-specific actions in human prostate stem and progenitor cells. Importantly, use of fresh human prostate specimens from organ donors and PCa patients will grant translational relevance to the findings. The detailed molecular results supported by in vivo responses of prostate cancer growth to SERMs have potential to identify new therapeutic targets for management of PCa and inform future drug discovery strategies using novel small molecules that target stem cell ER actions.