The Proteasome as Molecular Target of Grape Polyphenols

描述（由申请人提供）： 我们的长期目标是发现新的有效的，特异性的癌症预防和抗癌剂，没有细胞毒性。最近的体外、体内和临床试验结果支持使用蛋白酶体抑制剂作为潜在的新型抗癌药物。我们已经发现，天然和合成的绿色茶多酚与酯键是有效的和具体的蛋白酶体胰凝乳蛋白酶样抑制剂，而那些没有酯键是无活性的。最近，我们报道了葡萄提取物抑制白血病Jurkat T细胞提取物和完整Jurkat T细胞中的蛋白酶体糜蛋白酶样活性，与凋亡诱导相关。此外，葡萄提取物在前列腺癌PC-3中诱导球形细胞的出现优先于正常NIH 3 T3细胞系。我们的研究结果表明，蛋白酶体是葡萄抗氧化成分的癌症相关的分子靶点。基于这些结果，我们推测，抑制蛋白酶体活性的一些抗氧化多酚化合物有助于前列腺癌的预防活动的葡萄。为了解决这个问题，我们提出了以下三个具体目标。具体目的1是使用纯化的20 S蛋白酶体、前列腺癌细胞提取物和完整的前列腺癌细胞评价几种葡萄多酚化合物抑制蛋白酶体活性的效力和选择性。具体目标2是评估这些多酚化合物在人前列腺癌和正常细胞中的促前列腺增生诱导效力。具体目标3是确定这些葡萄抗氧化多酚化合物抑制蛋白酶体活性和诱导细胞凋亡的能力是否与它们在体内使用携带人前列腺癌细胞的裸鼠的癌症预防活性相关。这些研究应该有助于对葡萄和其他水果和蔬菜的消费如何预防癌症有一个基本的了解，并发现有效的，特异性的和稳定的多酚蛋白酶体抑制剂，没有或几乎没有毒性，用于预防前列腺癌和其他癌症。

DESCRIPTION (provided by applicant): Our long-term objective is to discover novel potent, specific cancer preventative and anticancer agents with no cytotoxicity. Recent results from in vitro, in vivo and clinical trials have supported the use of proteasome inhibitors as potential novel anticancer drugs. We have found that natural and synthetic green tea polyphenols with an ester bond are potent and specific proteasomal chymotrypsin-like inhibitors, while those without an ester bond are inactive. Most recently, we have reported that grape extract inhibits the proteasomal chymotrypsin-like activity in leukemia Jurkat T cell extract and intact Jurkat T cells, associated with apoptosis induction. Furthermore, grape extract induces the appearance of spherical cells preferentially in prostate cancer PC-3 over normal NIH 3T3 cell line. Our findings suggest that the proteasome is a cancer related molecular target for grape antioxidant components. Based on these results, we hypothesize that inhibition of the proteasome activity by some antioxidant polyphenolic compounds contributes to the prostate cancer-preventative activities of grapes. To address this hypothesis, we propose the following Three Specific Aims. Specific Aim 1 is to evaluate potency and selectivity of several grape polyphenolic compounds to inhibit the proteasome activity using purified 20S proteasome, prostate cancer cell extracts, and intact prostate cancer cells. Specific Aim 2 is to evaluate the apoptosis-inducing potency of these polyphenolic compounds in human prostate cancer and normal cells. Specific Aim 3 is to determine whether the abilities of these grape antioxidant polyphenolic compounds to inhibit the proteasome activity and to induce apoptosis correlate with their cancer-preventative activity in vivo using nude mice bearing human prostate cancer cells. These studies should help develop a fundamental understanding about how consumption of grapes and other fruits and vegetables prevents cancer, and discover potent, specific and stable polyphenol proteasome inhibitors with no or little toxicity for the prevention of prostate and other cancers.