Estrogen Receptors in Human Prostate Stem-Progenitor Cells

描述(申请人提供)：前列腺癌是一种激素依赖的组织，在整个生命过程中受到雄激素作用的调节。众所周知，雌激素在前列腺癌的发生和发展中起着重要的作用，促进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，但对前列腺癌中雌激素作用的机制尚不清楚。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高水平的雌激素受体-ER、ER和GPR30-并对雌二醇-17表现出更强的增殖反应。此外，初步数据表明，人类前列腺癌(PCA)干细胞中ER表达增加，这表明这一微小的肿瘤细胞群可能是直接的雌激素靶点。本研究的总体目标是阐明雌激素受体(ER、ER和GPR30)在正常和癌变的人前列腺癌的上皮干细胞和前体细胞中的作用，并阐明它们在促进或预防前列腺癌发生和发展中的具体作用。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在调节正常成人组织中人前列腺干细胞的自我更新、扩增、凋亡和/或分化中的具体作用。为了实现这一点，我们将利用一个完全特化的PROSTASHER系统来询问来自无疾病器官捐赠者的原代前列腺上皮培养的干细胞和祖细胞。目的2：探讨特异性内质网在人前列腺癌干细胞中的表达及其作用。来自患者标本的良性和前列腺癌细胞的原代上皮培养将被用来通过PROSTASHER分析来丰富干细胞/祖细胞。结果将通过询问两个永生化的人前列腺癌干细胞系HPET和HuSLC中的ER行为来支持。与正常和癌症相关的成纤维细胞的共培养研究将被用来确定正常和癌症人类前列腺中雌激素反应干细胞的生态位。目的3：阐明特异性内质网在体内介导激素性癌变和调控前列腺癌生长进展中的作用。利用正常人前列腺干细胞/祖细胞或人前列腺癌干细胞与胚胎间充质混合，建立了体内细胞重组移植模型，以产生与正常前列腺上皮或前列腺癌嵌合的前列腺样组织。靶向ER基因敲除和选择性雌激素受体调节剂(SERM)将被测试来描述体内的雌激素作用和调节PCa的生长。总之，本方法将为人类前列腺干细胞和祖细胞中ER特异性作用提供第一个直接证据。重要的是，使用来自器官捐赠者和前列腺癌患者的新鲜人类前列腺标本将与这一发现具有翻译相关性。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为前列腺癌的治疗确定新的治疗靶点，并利用针对干细胞ER活动的新的小分子为未来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.