Colon Cancer Chemoprevention by Grape Seed Extract

描述（由申请人提供）：结直肠癌（CRC）是人类癌症死亡的第二大常见原因，约5%的美国人口将在其一生中发展为CRC。总的来说，CRC的生长、进展和转移涉及遗传和表观遗传变化在数年内的逐渐积累。控制CRC生长和转移的一种方法可能是通过饮食中存在的植物化学物质和作为膳食补充剂消费的植物化学物质进行预防，这些植物化学物质抑制肿瘤阶段的一个或多个事件并降低整体癌症风险。葡萄籽提取物（GSE）是美国广泛消费的膳食补充剂，具有多种健康益处，并且是被称为原花青素的标准化植物化学物质的丰富来源。最近，我们观察到，GSE显着抑制生长，导致细胞周期停滞，并诱导人结肠癌HT 29，SW 480和LoVo细胞的凋亡，GSE喂养显着抑制HT 29肿瘤异种移植物在裸鼠中的生长，并防止息肉的形成及其在APC小鼠中的生长，而没有任何明显的毒性迹象，如在动物体重和饮食消耗方面测量的。在人CRC细胞系中的机制研究表明，GSE非常强烈地诱导Cip 1/p21水平，以及CDK和细胞周期蛋白的减少;在GSE处理的HT 29异种移植物中也观察到p21诱导。其他研究发现，GSE在CRC细胞系中引起强烈的半胱天冬酶3和PARP切割。我们还观察到GSE抑制CRC细胞中配体诱导的AKT活化。最近的研究还表明，GSE喂养防止氧化偶氮甲烷（AOM）诱导的大鼠模型结肠癌的发生，这与其在体内的抗增殖和凋亡作用有关。总之，基于这些研究，我们假设GSE是一种新型的结肠癌化学预防膳食补充剂，其靶向细胞周期进展和细胞存活信号传导，导致其对CRC的抗增殖和凋亡功效。我们的具体目标是：I）进一步评估和确定GSE在AOM诱导的大鼠CRC模型中的功效，II）确定GSE诱导Cip 1/p21在其针对CRC的生物功效中的作用，III）评估和确定GSE对促有丝分裂和细胞存活信号传导以及APC/β-连环蛋白/TCF 4途径的作用，以及IV）进一步检查和确定GSE对细胞凋亡调节剂的作用。我们预计，拟议的研究将确定GSE作为一种基于机制的膳食补充剂，用于预防CRC，并将建立其在临床前CRC模型中的体内疗效。作为一种实用和转化的方法，这些研究的长期目标是确定和建立GSE对预防和干预人类CRC的有用性。

DESCRIPTION (provided by applicant): Colorectal cancer (CRC) is the second most common cause of cancer deaths in humans, and about 5% of the US population will develop CRC in their life times. Overall, CRC growth, progression and metastasis involve a gradual accumulation of genetic and epigenetic changes over a period of years. One approach to control CRC growth and metastasis could be its prevention by phytochemicals present in diet and those consumed as dietary supplement, which inhibit one or more events of neoplastic stages and reduce overall cancer risk. Grape seed extract (GSE) is a widely consumed dietary supplement in the United States for its several health benefits, and is a rich source of standardized phytochemicals known as proanthocyanidins. Recently, we observed that GSE significantly inhibits growth, causes cell cycle arrest and induces apoptosis in human colon carcinoma HT29, SW480 and LoVo cells, and that GSE feeding significantly inhibits HT29 tumor xenograft growth in nude mice and prevents polyp formation and its growth in APCmin mice without any apparent signs of toxicity as measured in terms of animal body weight and diet consumption. Mechanistic studies in human CRC cell lines showed that GSE very strongly induces Cip1/p21 levels, together with a decrease in CDKs and cyclins; p21 induction was also observed in GSE-treated HT29 xenografts. Other studies found that GSE causes strong caspase 3 and PARP cleavage in CRC cell lines. We also observed that GSE inhibits ligand-induced AKT activation in CRC cells. Recent studies have also shown that GSE feeding prevents azoxymethane (AOM)-induced colon carcinogenesis in rat model, which was associated with its in vivo anti-proliferative and apoptotic effects. Together, based on these studies, we hypothesize that GSE is a novel colon cancer chemopreventive dietary supplement agent, which targets cell cycle progression and cell survival signaling leading to its anti-proliferative and apoptotic efficacy against CRC. Our specific aims are to: I) further assess and establish GSE efficacy in AOM-induced rat CRC model, II) establish the role of Cip1/p21 induction by GSE in its biological efficacy against CRC, III) assess and define GSE effect on mitogenic and cell survival signaling, and APC/p-catenin/ TCF4 pathway, and IV) further examine and define the effects of GSE on apoptosis regulators. We anticipate that proposed studies will identify GSE as a mechanism-based dietary supplement agent for the prevention of CRC, and will establish its in vivo efficacy in pre-clinical CRC models. As a practical and translational approach, the long- range goal of these studies would be to define and establish the usefulness of GSE for the prevention and intervention of human CRC.