Rapamycin Regulation of the Androgen Receptor: Implications in Prostate Cancer

项目摘要： 在该应用中，我们表明mTOR抑制剂雷帕霉素和抗雄激素药物的组合 比卡鲁胺对雄激素非依赖性前列腺癌的长期生长抑制和细胞凋亡 （AIPC）细胞，尽管两种药物都不具有与单一药剂相同的效果。目前的总体目标 该项目旨在阐明这种治疗影响的信号转导途径，从而导致细胞周期 停滞和凋亡。在初步研究中，我们提供了新的证据，表明比卡鲁胺单独不能 抑制细胞生长并诱导AIPC细胞凋亡，由于存在强雄激素非依赖性， 但对雷帕霉素敏感，是mTOR下游的存活途径。另一方面，雷帕霉素 由于AR依赖性细胞的刺激，单一疗法不能诱导长期生长抑制 通过雷帕霉素处理的存活途径。因此，我们假设mTOR和AR通路调节 前列腺癌细胞的存活是平行的，只有当两种途径都同时存在时才能诱导细胞凋亡 同时抑制。为检验这一假设，设计了以下具体目标： 1.为了验证抗雄激素比卡鲁胺不能诱导细胞凋亡的假设， 雄激素非依赖性前列腺癌细胞由于雄激素非依赖性的存在，但 雷帕霉素敏感，mTOR 1下游的细胞存活途径，mTOR的复合物。mTORC1 磷酸化下游靶点p70 S6激酶和4 E-BP 1，一种eIF 4 E结合蛋白。我们将确定 mTORC 1/4 E-BP 1/eIF 4 E通路的激活增加是否促进雄激素非依赖性细胞增殖 雄激素依赖性前列腺癌细胞的增殖和存活。此外，我们将研究是否 mTOR途径在雄激素非依赖性人前列腺癌组织中被激活。 2：检验用mTOR抑制剂长期治疗前列腺癌细胞的假设 雷帕霉素刺激AR转录活性，导致存活率增加和对 通过雷帕霉素的生长抑制。(i)我们将检验长期雷帕霉素治疗刺激 前列腺癌细胞中的AR转录活性。(ii)我们将检验雷帕霉素刺激的AR 转录活性导致细胞存活增加，这引起对雷帕霉素处理的抗性。 3.为了检验雷帕霉素和比卡鲁胺联合治疗诱导 前列腺癌细胞凋亡和预防AIPC。我们将确定雷帕霉素和 比卡鲁胺联合预防体内雄激素非依赖性前列腺肿瘤的生长。我们还 将研究雷帕霉素和比卡鲁胺联合治疗雄激素依赖性 在前列腺癌进展的模型中，前列腺肿瘤预防前列腺肿瘤的复发。

PROJECT ABSTRACT: In this application, we show that the combination of the mTOR inhibitor rapamycin and the anti-androgen bicalutamide caused long-term growth inhibition and apoptosis in androgen independent prostate cancer (AIPC) cells despite neither drug having the same effect as single agents. The overall objective of the present project is to elucidate the signal transduction pathways affected by this treatment, which lead to cell cycle arrest and apoptosis. In preliminary studies, we provide novel evidence that bicalutamide alone was unable to inhibit cell growth and induce apoptosis in AIPC cells, due to the presence of a strong androgen-independent, but rapamycin-sensitive, survival pathway downstream of mTOR. On the other hand, rapamycin as monotherapy was unable to induce long-term growth inhibition due to the stimulation of an AR-dependent cell survival pathway by rapamycin treatment. Thus we hypothesize that the mTOR and AR pathways regulate survival in prostate cancer cells in parallel, and apoptosis was induced only when both pathways were simultaneously inhibited. The following specific aims have been designed to test this hypothesis: 1. To test the hypothesis that the anti-androgen bicalutamide is unable to induce apoptosis in androgen-independent prostate cancer cells due to the presence of an androgen-independent, but rapamycin-sensitive, cell survival pathway downstream of mTORC1, a complex of mTOR. mTORC1 phosphorylates downstream targets p70S6 kinase and 4E-BP1, an eIF4E binding protein. We will determine whether increased activation of the mTORC1/4E-BP1/eIF4E pathway promotes androgen-independent cell proliferation and survival in androgen-dependent prostate cancer cells. In addition, we will examine whether the mTOR pathway is activated in androgen-independent human prostate cancer tissues. 2: To test the hypothesis that long-term treatment of prostate cancer cells with the mTOR inhibitor rapamycin stimulates AR transcriptional activity resulting in increased survival and resistance to growth inhibition by rapamycin. (i) We will test the hypothesis that long-term rapamycin treatment stimulates AR transcriptional activity in prostate cancer cells. (ii) We will test the hypothesis that rapamycin-stimulated AR transcriptional activity results in increased cell survival which causes resistance to rapamycin treatment. 3. To test the hypothesis that combination treatment with rapamycin and bicalutamide induce apoptosis in prostate cancer cells and prevent AIPC. We will determine whether rapamycin and bicalutamide in combination prevent the growth of androgen-independent prostate tumors in vivo. Further, we will investigate whether combination treatment with rapamycin and bicalutamide in androgen-dependent tumors prevent the recurrence of prostate tumors in a model of prostate cancer progression.