Prostate cancer chemoprevention by penta-galloyl-glucose

描述(由申请人提供)： 该研究项目的总体目标是开发东方草药化合物1，2，3，4，6-五-O-没食子酰-β-D-葡萄糖(PGG)，用于化学预防前列腺癌(PCA)，前列腺癌是美国男性癌症死亡的第二大原因。我们的初步数据显示，PGG诱导人LNCaP(P53野生型，雄激素依赖)和DU145(突变型P53，雄激素非依赖性)PCa细胞G1期和S期阻滞，以及caspase介导的涉及活性氧(ROS)的细胞凋亡。我们的数据表明，PGG用于化学预防的新靶点/途径包括快速抑制DNA复制合成，激活P53肿瘤抑制因子和失活STAT3癌信号，与细胞周期蛋白D1(细胞周期)和Bcl-xl/Mcl-1(细胞存活)下调相关。此外，PGG显著抑制人DU145-PCa裸鼠移植瘤的体内生长，且对体重无不良影响。在我们的合作者Sung-Hoon Kim完成的工作中，PGG具有强大的抗血管生成活性，并在小鼠肺癌模型中发挥强大的抗肿瘤作用。我们推测，PGG通过不同的G1和S阻滞机制抑制癌细胞增殖，诱导P53依赖和非依赖的细胞凋亡，并通过抑制血管生成来预防PCa。我们建议实现5个具体目标来检验这些假设。目的：1.从DNA损伤/复制应激检查点通路(如atm/atr、p53)的角度，探讨前列腺素G抑制DNA复制合成及其在S细胞周期阻滞和细胞凋亡中的作用。目的：研究细胞周期蛋白D_1和信号转导通路STAT3在前列腺素G_2抑制血管内皮细胞G1期进展中的作用，并验证其抑制血管内皮细胞增殖的作用机制之一。目的3.检测ROS在细胞周期停滞和细胞凋亡信号转导中的作用及其亚细胞来源，并评价内源性和外源性caspase级联通路的作用。在上述细胞培养模型中，将使用生化、药理学和遗传学方法来确定因果关系。目的：建立前列腺素G对转基因小鼠前列腺癌(TRAMP)原发前列腺癌模型的化学预防作用。目的5.利用Aim 4的合适组织，在体内鉴定包括细胞增殖、细胞凋亡、血管生成和PGG分子靶点(如细胞周期蛋白D1、p-STAT3、Bcl2家族、血管内皮生长因子)在内的化学预防作用的生物标志物。细胞培养研究(AIMS 1-3)将通过不同的细胞周期G1和S阻滞以及caspase介导的血管内皮细胞凋亡来全面了解PGG化学预防作用的新机制、靶点和途径。动物研究(目标4)将测试PGG抑制前列腺癌发生的优点，特别是预防或延缓雄激素非依赖性前列腺癌的发生。AIM 5中的生物标志物分析将有助于在体内识别和验证PGG化学预防效果的相关分子靶点和途径。该研究项目的总体目标是开发东方草药化合物1，2，3，4，6-五-O-没食子酰-β-D-葡萄糖(PGG)，用于化学预防前列腺癌(PCA)，前列腺癌是美国男性癌症死亡的第二大原因。化学预防已被认为是降低PCa发病率和死亡率的一种合理且经济有效的替代方法。我们的建议得到了令人兴奋的初步数据的支持，这些数据表明，PGG不仅通过G1期阻滞，而且通过S阻滞并诱导半胱氨酸天冬氨酸酶介导的凋亡来抑制前列腺癌细胞的增殖。特别是，我们的初步数据支持，在不同雄激素依赖和P53状态的PCa细胞中，PGG有效且快速地抑制DNA复制合成，作为主要的抗增殖机制。据我们所知，到目前为止还没有关于癌症化学预防药物的描述。公共卫生相关性：对机制的拟议阐明可能导致建立一种新的范例，不仅可用于前列腺癌，还可用于其他器官部位的癌症的新型化学预防药物。这些多重靶向活动和已发表的支持抗血管生成活性的工作为测试前列腺癌化学预防的有效性提供了强有力的理论基础。

DESCRIPTION (provided by applicant): The overall goal of this research project is to develop Oriental herbal compound 1,2,3,4,6-penta-O-galloyl- beta-D-glucose (PGG) for the chemoprevention of prostate cancer (PCa), the number 2 cause of cancer death in US men. Our preliminary data show that PGG induced G1 and S-phase arrests in human LNCaP (p53 wild type, androgen dependent) and DU145 (mutant p53, androgen independent) PCa cells as well as caspase- mediated apoptosis involving reactive oxygen species (ROS). We data suggest novel targets/pathways of PGG for chemoprevention include a rapid inhibition of DNA replicative synthesis, and an activation of the p53 tumor suppressor and inactivating the Stat3 oncogenic signaling, associated with cyclin D1 (cell cycle) and Bcl-xL/Mcl-1 (cell survival) down regulation. Furthermore, PGG significantly inhibited the in vivo growth of human DU145 PCa xenografts in nude mice without adverse effect on body weight. In work accomplished by our collaborator Sung-Hoon Kim, PGG possesses potent anti-angiogenic activities and exerts a strong anti- tumor effect in a mouse lung cancer model. We hypothesize that PGG prevents PCa by inhibiting cancer cell proliferation through distinct G1 and S arrest mechanisms, inducing p53-dependent and -independent apoptosis and by inhibiting angiogenesis. We propose to accomplish 5 specific aims to test these hypotheses. Aim 1. To determine how PGG inhibits DNA replicative synthesis and the role in S-arrest and apoptosis with an emphasis on DNA damage/replicative stress-checkpoint pathways (e.g., ATM/ATR, p53). Aim 2. To investigate the role of cyclin D1 and Stat3 as targets for PGG to inhibit G1 progression and validate G1- and S- arrest mechanisms in mitogen-activated vascular endothelial cells as one mechanism of anti-angiogenesis action of PGG. Aim 3. To test the role and the subcellular origin of ROS in cell cycle arrests and apoptosis signaling and evaluate the contribution of the intrinsic and the extrinsic caspase cascades. In the above cell culture models, biochemical, pharmacological and genetic approaches will be used to establish cause-effects. Aim 4. To establish the chemopreventive efficacy of PGG against the autochthonous transgenic adenocarcinoma mouse prostate (TRAMP) model of primary prostate carcinogenesis. Aim 5. To characterize in vivo biomarkers of chemopreventive efficacy including cell proliferation, apoptosis, angiogenesis and molecular targets of PGG (e.g., cyclin D1, p-Stat3, Bcl-2 family, VEGF) using suitable tissues from Aim 4. The cell culture studies (Aims 1-3) will provide a comprehensive understanding of the novel mechanisms, targets and pathways of chemopreventive action of PGG through distinct cell cycle G1 and S-arrests and caspase-mediated apoptosis in PCa cells and in vascular endothelial cells. The animal studies (Aim 4) will test the merit of PGG to inhibit primary prostate carcinogenesis and in particular the prevention or delay of genesis of androgen-independent PCa. The biomarker analyses in Aim 5 will help to identify and validate in vivo relevant molecular targets and pathways for the chemopreventive efficacy of PGG. The overall goal of this research project is to develop Oriental herbal compound 1,2,3,4,6-penta-O-galloyl-beta- D-glucose (PGG) for the chemoprevention of prostate cancer (PCa), the number 2 cause of cancer death in US men. Chemoprevention has become recognized as a plausible and cost-effective alternative approach to reduce the morbidity and mortality of PCa. Our proposal is supported by exciting preliminary data that suggest novel mechanisms/targets for PGG to inhibit prostate cancer cell proliferation through not only G1 arrest but also S arrest and induces caspase-mediated apoptosis. In particular, our preliminary data support a potent and rapid inhibition of DNA replicative synthesis by PGG in PCa cells of diverse androgen-dependence and p53 status as a primary anti-proliferative mechanism. This, to our knowledge, has not been described for cancer chemopreventive agents so far studied. PUBLIC HEALTH RELEVANCE: The proposed elucidation of the mechanisms could lead to the establishment of a new paradigm for a novel class of chemopreventive agents for not only prostate cancer, but also cancers of other organ sites. These multiple targeting activities plus published work supporting anti- angiogenesis activity provide strong rationale for testing the efficacy of PGG for prostate cancer chemoprevention.