Dietary prevention of prostate cancer

描述（由申请人提供）：我们的研究重点是对癌症具有化疗和/或化学预防特性的天然化合物。在拟议的研究中，我们将表征化合物Withaferin-A（WA）的作用机制，该化合物是一种广泛用于亚洲和非洲传统医学的催眠Withania的生物活性化合物。WA对雄激素依赖性和雄激素非依赖性前列腺癌（分别为ADPC和AIPC）显示出令人印象深刻的选择性活性，其中后者对所有现有形式的治疗都是难治的。我们的初步体外和体内数据表明，WA通过抑制Akt（一种激活细胞存活途径的蛋白激酶）的活性靶向ADPC和AIPC细胞。我们的初步数据表明，伴随着ADPC和AIPC细胞中Akt的抑制，WA激活FOXO 3a，FOXO 3a进而激活前列腺凋亡反应-4（Par-4），Par-4是一种选择性诱导癌细胞凋亡的蛋白质。基于我们的结果，我们假设WA克服了Akt对CREB/Par-4信号传导的负面影响，以实现对AIPC的化学预防和/或化疗效果。为了验证这一假设，我们提出了以下目标：研究Akt/CREB和Par-4信号之间的相互作用（目的1）;以及WA如何调节AIPC中的促凋亡信号（目的2）;评估WA对小鼠前列腺转基因腺癌（TRAMP）模型中雄激素非依赖性前列腺肿瘤生长的影响（目的3）;并在TRAMP和/或TRAMP细胞系中检查WA介导的肿瘤抑制的机制（目的4）。对于我们研究的体外部分，我们将使用多种方法（免疫沉淀、siRNA策略、免疫荧光、Western印迹、北方印迹、芯片测定、siRNA策略、下拉测定、药理学阻断）以确定Akt/CREB 3a和Par-4会聚的分子连接。对于我们的体内研究，我们将进行肿瘤消退研究，但我们还将检查组织病理学、细胞死亡、肿瘤组织中促存活蛋白和促凋亡蛋白的表达模式以及血清和前列腺组织中的WA水平。我们的长期目标是将天然化合物推广到临床环境中，在那里可以彻底评估这些药物的化学预防和化学治疗特性。我们的初步数据表明，WA是一个潜在的候选人，这样的临床评价，我们提出的研究将阐明其对前列腺癌的效力，无论是从化学预防和化疗的角度在一个机制的水平。

DESCRIPTION (provided by applicant): Our research focuses on natural compounds that possess chemotherapeutic and/or chemopreventive properties with respect to cancer. In the proposed study, we will characterize the mechanism of action of the compound Withaferin-A (WA), a bioactive compound of Withania somnifera, which is extensively used in Asian and African traditional medicine. WA displays impressive and selective activity against androgen- dependent and androgen-independent prostate cancer (ADPC and AIPC, respectively), of which the latter is refractory to all current forms of treatment. Our preliminary in vitro and in vivo data indicate WA targets ADPC and AIPC cells by inhibiting the activity of Akt, a protein kinase that activates cell survival pathways. Our preliminary data demonstrate that, concomitant to Akt inhibition in ADPC and AIPC cells, WA activates FOXO3a, which in turn activates prostate apoptosis response-4 (Par-4), a protein that selectively induces apoptosis in cancer cells Based on our results, we hypothesize WA overrides the negative effects of Akt on CREB/Par-4 signaling to achieve chemopreventive and/or chemotherapeutic effects on AIPC. To address this hypothesis, we propose the following aims: investigate the interaction between Akt/CREB and Par-4 signaling, (Aim 1); and how WA modulates the pro-apoptotic signaling in AIPC (Aim 2); evaluate the effects of WA on androgen- -independent prostate tumor growth in the transgenic adenocarcinoma of mouse prostate (TRAMP) model (Aim 3); and examine the mechanisms of WA-mediated tumor inhibition in TRAMP and/or TRAMP cell lines (Aim 4). For the in vitro arm of our studies we will use a variety of approaches (immunoprecipitation, siRNA strategies, immunofluorescence, Western blot, Northern blots, Chip assays, siRNA strategies, pull down assays, pharmacological blocking) in order to determine the molecular junction at which Akt/CREB 3aand Par-4 converge. For our in vivo studies, we will conduct tumor regression studies, yet we will also examine histopathology, cell death, expression patterns of pro-survival proteins and pro-apoptotic proteins in the tumor tissues, and WA levels in the serum and prostate tissue. Our long term goal is to promote natural compounds to a clinical environment, where these agents can be thoroughly assessed for their chemopreventive and chemotherapeutic properties. Our preliminary data indicate WA is a potential candidate for such clinical evaluation, and our proposed studies will elucidate at a mechanistic level its potency against prostate cancer, both from a chemopreventive and chemotherapeutic standpoint.