Estrogen Receptors in Human Prostate Stem-Progenitor Cells

描述（由申请人提供）：前列腺是一个终生受雄激素作用调节的激素依赖性组织。众所周知，雌激素在前列腺发育和体内平衡中起着关键作用，并有助于前列腺癌的发生和发展。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，但雌激素在前列腺中的作用机制尚不清楚。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了高水平的雌激素受体——ER¿、ER¿和GPR30，并对雌二醇-17¿表现出增加的增殖反应。此外，初步数据表明，人前列腺癌（PCa）干细胞样细胞中ER表达升高，表明这种次要肿瘤细胞群可能是雌激素的直接靶点。本研究的总体目标是描述雌激素受体（ER¿，ER¿和GPR30）在正常和癌性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发生和进展中的具体作用。为实现这些目标，提出了三个具体目标。目的1：明确ER¿、ER¿和GPR30在正常成人组织中调节人前列腺干细胞祖细胞自我更新、扩增、凋亡和/或分化中的具体作用。为了实现这一目标，我们将利用一个完全表征的前列腺球系统来询问来自无病器官供者的原代前列腺上皮培养的干细胞和祖细胞。目的2：阐明特异性内质网在人前列腺癌干细胞中的表达和作用。来自患者标本的良性和前列腺癌细胞的原代上皮培养物将用于通过前列腺球试验富集干细胞/祖细胞。结果将通过对两种永生化人PCa干细胞样细胞系HPET和HuSLC的ER作用进行询问来支持。与正常和癌症相关成纤维细胞的共培养研究将用于确定正常和癌变人类前列腺中的雌激素应答干细胞生态位。目的3：描述特异性内质网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。利用正常人前列腺干细胞/祖细胞或人前列腺干细胞样细胞与胚胎间充质混合，建立了与正常人前列腺上皮或前列腺癌嵌合的前列腺样组织的体内细胞重组移植模型。将测试靶向ER敲除和选择性雌激素受体调节剂（SERMs）来描述雌激素的作用和调节体内PCa的生长。总之，目前的方法将为人类前列腺干细胞和祖细胞中的er特异性作用提供第一个直接证据。重要的是，使用来自器官捐献者和前列腺癌患者的新鲜人类前列腺标本将使研究结果具有翻译相关性。前列腺癌生长对SERMs的体内反应所支持的详细分子结果有可能确定前列腺癌管理的新治疗靶点，并为未来使用靶向干细胞内质网作用的新型小分子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.