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结直肠癌。总体而言，结直肠癌的生长、进展和转移涉及多年来遗传和表观遗传变化的逐渐积累。一种控制结直肠癌生长和转移的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的植物化学物质来预防结直肠癌的生长和转移，这些植物化学物质可以抑制肿瘤分期的一个或多个事件并降低总体癌症风险。葡萄籽提取物（GSE）在美国是一种广泛食用的膳食补充剂，因为它具有多种健康益处，而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显著抑制人结肠癌HT29、SW480和LoVo细胞的生长、导致细胞周期阻滞和诱导细胞凋亡，并且GSE喂养显著抑制裸鼠HT29肿瘤异种移植物的生长，阻止APCmin小鼠息肉的形成和生长，且通过动物体重和饮食消耗测量无明显毒性迹象。在人结直肠癌细胞系中的机制研究表明，GSE非常强烈地诱导Cip1/p21水平，同时CDKs和细胞周期蛋白减少；在gse处理的HT29异种移植物中也观察到p21的诱导。其他研究发现，GSE在结直肠癌细胞系中引起强烈的caspase 3和PARP裂解。我们还观察到GSE抑制CRC细胞中配体诱导的AKT活化。最近的研究也表明，在大鼠模型中，GSE喂养可防止azoxymethane （AOM）诱导的结肠癌发生，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，其靶向细胞周期进程和细胞存活信号，从而具有抗CRC增殖和凋亡的功效。我们的具体目标是：1)进一步评估和确定GSE在aome诱导的大鼠CRC模型中的疗效，2)确定GSE诱导Cip1/p21在其抗CRC生物学疗效中的作用，3)评估和确定GSE对有丝分裂和细胞存活信号通路以及APC/p-catenin/ TCF4通路的影响，4)进一步研究和确定GSE对凋亡调节因子的影响。我们预计，拟议的研究将确定GSE作为一种基于机制的预防CRC的膳食补充剂剂，并将在临床前CRC模型中确定其体内功效。作为一种实用和可转化的方法，这些研究的长期目标是确定和建立GSE在预防和干预人类结直肠癌方面的有用性。

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.