SIRT1 as a Resveratrol target in PTEN knockout Prostate Cancer Model

描述（由申请人提供）：衰老是前列腺癌（PCA）的主要危险因素之一，前列腺癌是男性癌症相关死亡的第二大原因。流行病学研究表明，饮食习惯包括食用水果和蔬菜的东方人群前列腺癌发病率较低。这些数据暗示无毒的生物活性食品成分可以预防前列腺癌。因此，了解与年龄依赖性前列腺癌风险增加相关的分子致病因素对于制定有效的前列腺癌管理策略至关重要。沉默信息调节因子1 （SIRT1）已被证明可以延长寿命，这意味着SIRT1在衰老中起作用。白藜芦醇是葡萄、浆果和花生皮中发现的一种植物抗毒素，在SIRT1活性调节剂的筛选中，白藜芦醇被确定为最有效的SIRT1激活剂。白藜芦醇已被证明在包括前列腺在内的各种模型中抑制肿瘤的发展。然而，目前尚不清楚SIRT1激活是否可以作为一种新的癌症预防靶点。作为原理证明，我们假设白藜芦醇诱导SIRT1激活通过调节akt介导的NFkB和FOXO3a信号的激活来阻止前列腺癌的发生。据我们所知，在体内模型中，SIRT1作为预防前列腺癌的分子靶点的相关性尚未得到测试。本试点提案的主要目的是通过各种分子和生化研究来证明(i) SIRT1信号在抑制前列腺癌细胞生长中的重要性（ii）通过PTEN敲除小鼠模型通过SIRT1信号通路通过膳食给药白藜芦醇预防前列腺癌的能力。我们将使用免疫组织化学、western blotting、RT-PCR和组织样本的酶活性（SIRT1）来验证与其生物活性相关的分子靶点。由于内源性肿瘤抑制基因（PTEN）失活，我们选择的动物模型在不同阶段发展为类似于人类前列腺癌的前列腺癌，而内源性肿瘤抑制基因（PTEN）在大多数人类前列腺肿瘤中经常缺失。因此，在该模型中获得的结果将有直接的转化应用于治疗用途。这些目标与计划公告PA-07-362的重点是生物活性食品成分分子靶点的鉴定和表征非常吻合。公共卫生相关性：前列腺癌（PCA）是一个主要的健康问题，发病率随着年龄的增长而增加。本提案的目标是在PCA的临床前模型中测试一种延长寿命、具有成本效益和无毒的膳食补充剂，该模型针对新的SIRT1信号（与延长寿命相关）预防前列腺癌。

DESCRIPTION (provided by applicant): Aging is one of the major risk factors for prostate cancer (PCA) which is the second leading cause of cancer related deaths in men. Epidemiological studies show lower incidence of prostate cancer in Oriental population whose dietary habits include consumption of fruits and vegetables. These data implicate non toxic bioactive food components in prostate cancer prevention. Therefore understanding the molecular causative factors associated with the age-dependent increase in the risk of prostate cancer are critical for developing effective strategies for its management. Silent information regulator 1 (SIRT1) has been shown to increase life span implicating a role for SIRT1 in aging. Resveratrol, a phytoalexin found in the skin of grapes, berries and peanuts has been identified as the most potent SIRT1 activator in a screen for identifying modulators of SIRT1 activity. Resveratrol has been shown to inhibit tumor development in various models including prostate. However it is not known if SIRT1 activation can be exploited as a novel cancer-prevention target. As proof of principle we hypothesize that Resveratrol induced SIRT1 activation prevents prostate carcinogenesis through modulation of Akt-mediated activation of NFkB and FOXO3a signaling. To the best of our knowledge the relevance of SIRT1 as a molecular target for preventing prostate cancer in an in vivo model has not been tested. The major objective of this pilot proposal is to demonstrate the (i) importance of SIRT1 signaling in inhibiting prostate cancer cell growth using a variety of molecular and biochemical studies (ii) ability of dietary administration of Resveratrol to prevent prostate cancer using PTEN knock-out mouse model through SIRT1 signaling pathway. We will validate the molecular targets associated with its biological activity using immunohistochemistry, western blotting, RT-PCR and enzymatic activities (SIRT1) from tissue samples. The animal model we chose develops prostate cancer resembling human prostate cancer in distinct stages due to inactivation of endogenous tumor suppressor gene (PTEN) that is frequently deleted in majority of human prostate tumors. Therefore the results obtained in this model will have direct translational application for therapeutic use. These objectives fit well with the program announcement PA-07-362 focusing on the identification and characterization of molecular targets for bioactive food components. PUBLIC HEALTH RELEVANCE: Prostate cancer (PCA) is a major health problem with incidence increasing with age. The goal of this proposal is to test a life-span increasing, cost-effective and non toxic dietary supplement in a preclinical model of PCA targeting novel SIRT1 signaling (associated with increasing life span) for prostate cancer prevention.