Mammalian Target of Rapamycin in Prostate Carcinogenesis

描述(由申请人提供)： 哺乳动物雷帕霉素靶标(MTOR)在营养和微环境信号的作用下，调节一系列控制细胞增殖、细胞生长和血管生成的特定基因的翻译；mTOR还独立地调节细胞的存活。在前列腺癌中，上游抑制物突变失活和上游mTOR激活物功能增强已被证实。然而，mTOR在营养应激的微环境中以及在正常、肿瘤和恶性的完整动物的前列腺中发挥作用的生物学尚不清楚。在这项建议中，我们操纵了前列腺癌细胞和一组独特的基因定义的前列腺上皮细胞系中的mTOR功能，以确定在提供有限的营养、能量底物和氧气的情况下对肿瘤和恶性肿瘤生存的调节。我们还测试了生物黄酮类的mTOR抑制以及对营养和能量限制的反应。与此同时，我们在转基因小鼠的前列腺上皮中设计了mTOR功能的获得，并使用一套组织病理学、增殖、微血管形态和密度、细胞凋亡和侵袭性的检测来测试前列腺癌在前列腺生长、血管生成、雄激素反应性、肿瘤进展以及生长和转移扩散方面的变化。我们的具体目标是：1.确定PI3-K/AKT/mTOR功能的获得或丧失是否会改变已建立的前列腺癌细胞系(PC-3、LN-CAP和DU145)在营养和氧气应激条件下的生存和/或增殖能力。2.确定营养响应mTOR信号通路是否是染料木素和其他生物黄酮类化合物在前列腺癌化学预防中的相关分子靶点。3.测定mTOR功能的增加以及前列腺生长、血管生成和雄激素反应性的改变。4.在前列腺发育不良的遗传模型中测试mTOR功能和肿瘤进展的增益。5.在前列腺癌发生、局部转移和远处转移的小鼠模型(Probove-SV40Tag-TRAMP)中测试mTOR功能的增益。在这项建议完成后，我们将在与人类前列腺癌发生密切相关的明确遗传改变的背景下，确定在营养-微环境底物可用性的双重压力下，前列腺癌细胞mTOR功能的分子和生物学机制。最终，这项研究可能会建议对mTOR信号系统进行新的操作，以防止或抑制前列腺癌的生长和扩散。

DESCRIPTION (provided by applicant): Mammalian target of rapamycin (mTOR) regulates translation of a select repertoire of mRNA's controlling proliferation, cell growth and angiogenesis in response to nutritional and microenvironmental signals; mTOR also independently regulates cell survival. Mutational inactivation of upstream inhibitors and gain of function of upstream mTOR activators have been demonstrated in prostate cancer. However, the biology of mTOR function in nutritionally stressed microenvironments and in normal, neoplastic, and malignant prostate of the intact animal is unknown. In this proposal, we manipulate mTOR function in prostate cancer cells and a unique set of genetically defined prostate epithelial cell lines to determine regulation of neoplastic and malignant survival in face of provision of limited nutrients, energy substrates and oxygen. We also test bioflavonoid mTOR inhibition and response to nutrient and energy restriction. In parallel, we engineer gain of mTOR function in the prostatic epithelium of transgenic mice and use a suite of assays for histopathology, proliferation, microvascular morphology and density, apoptosis, and invasion, to test changes in prostate growth, angiogenesis, androgen responsiveness, neoplastic progression, and growth and metastatic spread of prostate cancer. Our Specific Aims are: 1. Determine whether gain or loss of PI3- kinase/AKT/mTOR function alters the ability of established prostate cancer cell lines (PC-3, LN-CAP, and DU145) to survive and/or proliferate under conditions of nutrient and oxygen stress. 2. Determine whether the nutrient-responsive mTOR-signaling pathway is a relevant molecular target for genistein and other bioflavonoid compounds implicated in prostate cancer chemoprevention. 3. Determine gain of mTOR function and alteration of prostate growth, angiogenesis, and androgen responsiveness. 4. Test gain of mTOR function and neoplastic progression in a genetic model of prostate dysplasia. 5. Test gain of mTOR function in a mouse model (probasin-SV40Tag-TRAMP) of prostate carcinogenesis, loco-regional, and distant metastasis. At completion of this proposal we will determine both molecular and biological mechanisms of mTOR function in prostate cancer cells under the dual stress of nutrient-microenvironmental substrate availability in the context of defined genetic alterations germane to human prostate carcinogenesis. Ultimately this research may suggest novel manipulations of the mTOR signaling system to either prevent or inhibit prostate cancer growth and spread.