Prostate Cancer Prevention by Procyanidins in Grape Seed Extract

6.项目摘要 前列腺癌（PCA）是老年男性中最常见的恶性肿瘤， 男性癌症死亡的原因。恶性肿瘤从癌前病变发展到晚期病变有很长的潜伏期。 充分发展的癌症提供了充足的时间来干预或改变这种疾病的进展， 化学预防策略此外，许多研究表明，某些癌症的风险可能是 通过饮食控制，特别是通过增加水果和蔬菜的消费来降低。因此， 一直对确定饮食或饮食成分（营养和非营养植物化学物质）非常感兴趣 作为化学预防剂的潜在用途。葡萄籽提取物（GSE），一种丰富的和商业上可获得的 原花青素（也称为原花青素）的来源，通常作为健康补充剂食用，因为其广泛的 一系列有益效果。关于癌症，我们和其他人的几项研究表明， 以及GSE对包括PCA细胞在内的各种上皮恶性肿瘤的化学预防功效。自从GSE 代表多酚的复杂混合物，在上一个资助期内，研究的中心重点是 分离和表征GSE中活性成分，以进行详细的机制和功效研究， 使用纯的和确定的试剂的抗癌活性。我们最近分离并鉴定了原花青素B2- 3，3 '-二-O-没食子酸酯（B2-G2）是GSE中的一个活性化合物，对人前列腺具有较强的抗癌活性 DU 145细胞。对这种化合物的进一步研究表明，它被PCA细胞吸收， 引起细胞毒性以及细胞生长抑制作用。进一步的研究表明，B2-G2导致这两种疾病， 在携带功能性雄激素受体的人PCA细胞中的细胞周期阻滞和凋亡诱导;这些细胞 特别代表大多数人前列腺肿瘤。重要的是，B2-G2在正常人中未显示细胞毒性。 人前列腺上皮和基质细胞，显示其在人PCA细胞中的选择性。由于不受控制 由于细胞周期进程失调导致的增殖和凋亡功能的丧失是主要的潜在原因。 由于B2-G2在大多数癌症中存在缺陷，包括PCA，并且由于B2-G2发挥强烈的细胞周期停滞和凋亡， 在PCA细胞中的反应，我们的中心假设是原花青素B2- 3，3 '-二-O-没食子酸酯选择性地诱导细胞 细胞周期阻滞和细胞凋亡，共同导致其预防性 和对PCA的治疗效果。我们的具体目标是：1）准备B2-G2所需的计划 机制、生物利用度和有效性研究，2）进行体外研究，以阐明B2-G2的作用机制 参与细胞周期阻滞和细胞凋亡，以及3）使用一种抑制剂测定B2-G2的功效和生物利用度。 小鼠前列腺的体内转基因癌（TRAMP）模型，其紧密且自然地模拟了 人类前列腺癌的进展。总的来说，我们的长期目标是开发原花青素B2- 3，3 '-二- O-没食子酸酯作为一种基于机理的潜在的PCA化学预防剂。7.项目叙述 前列腺癌是美国癌症相关死亡的第二大原因，因此是一个重要的癌症。 公共卫生问题。使用化学预防剂似乎是控制 前列腺癌，因为它有很长的潜伏期的发展;有时超过十年，从前驱病变， 全面爆发的疾病目前的赠款提案侧重于开发一种这样的代理， 从葡萄籽提取物中分离出来，这是一种广泛使用的健康补充剂。我们提议的研究结果 将提供用于预防人类前列腺癌的基于机制的药剂。

6. PROJECT SUMMARY ABSTRACT Prostate cancer (PCA) is the most frequently diagnosed malignancy in elderly men, and is rated as second leading cause of cancer deaths in men. The malignancy has long latent period of development from pre-neoplastic lesion to full-blown cancer providing ample time to intervene or alter the progression of this disease employing chemopreventive strategies. Additionally, numerous studies have shown that the risk for certain cancers could be lowered by dietary manipulations, especially by increased consumption of fruits and vegetables. Accordingly, there has been serious interest in identifying diets or dietary constituents (both nutritive and non-nutritive phytochemicals) for their potential use as chemopreventive agents. Grape seed extract (GSE), a rich and commercially available source of proanthocyanidins (also known as procyanidins), is usually consumed as a health supplement for its wide range of beneficial effects. Regarding cancer, several studies by us and others have demonstrated the anti-cancer and chemopreventive efficacy of GSE against various epithelial malignancies including PCA cells. Since GSE represents a complex mixture of polyphenols, the central focus of the studies during the last funding period was to isolate and characterize active component(s) in GSE to carry out detailed mechanistic and efficacy studies for anticancer activity employing pure and defined agents. We recently isolated and characterized procyanidin B2- 3,3'-di-O-gallate (B2-G2) as an active compound from GSE with strong anti-cancer activity against human prostate carcinoma DU145 cells. Further studies with this compound revealed that it is taken up by PCA cells and that it causes both cytotoxic as well as cell growth inhibitory effects. Additional studies revealed that B2-G2 causes both cell cycle arrest and apoptosis induction in human PCA cells carrying functional androgen receptor; these cells specifically represent majority of human prostate tumors. Importantly, B2-G2 did not show cytotoxicity in normal human prostate epithelial and stromal cells, showing its selectivity in human PCA cells. Since uncontrolled proliferation due to deregulated cell cycle progression and loss of apoptotic function are the major underlying defects in most of the cancers including PCA and since B2-G2 exerts strong cell cycle arrest and apoptotic responses in PCA cells, our central hypothesis is that procyanidin B2-3,3'-di-O-gallate selectively induces cell cycle arrest and apoptosis in neoplastic prostate epithelial cells which collectively leads to its preventive and therapeutic efficacy against PCA. Our specific aims are to: 1) prepare B2-G2 needed for planned mechanistic, bioavailability and efficacy studies, 2) conduct in vitro studies to address mechanism of action of B2-G2 involved in cell cycle arrest and apoptosis, and 3) determine efficacy and bioavailability of B2-G2 employing an in vivo transgenic carcinoma of the mouse prostate (TRAMP) model, which closely and naturally mimics the progression of prostatic carcinoma in humans. Overall, our long term goal is to develop procyanidin B2-3,3'-di- O-gallate as a mechanism-based potential chemopreventive agent against PCA. 7. PROJECT NARRATIVE Prostate cancer is second leading cause of cancer-related deaths in United States, and thus is an important public health issue. Use of chemopreventive agents seems to be more effective approach for the control of prostate cancer as it has long latent period of development; sometimes over decade from precursor lesions to full blown disease. Current grant proposal focuses on the development of one such agent, which has been isolated from grape seed extract, a widely consumed health supplement. Outcomes of our proposed research will provide a mechanism-based agent for the prevention of prostate cancer in humans.