Prostate cancer chemoprevention by penta-galloyl-glucose

本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）用于前列腺癌（PCa）的化学预防，PCa是癌症死亡的第二大原因 在美国男人。我们的初步数据表明，PGG诱导人LNCaP（p53野生型）细胞G1期和S期阻滞 型，雄激素依赖性）和DU 145（突变型p53，雄激素非依赖性）PCa细胞以及半胱天冬酶- 介导的凋亡，涉及活性氧（ROS）。我们的数据表明，新的目标/途径 PGG的化学预防作用包括快速抑制DNA复制合成和激活p53 肿瘤抑制和失活Stat 3致癌信号，与细胞周期蛋白D1（细胞周期）和 Bcl-xL/Mcl-1（细胞存活）下调。此外，PGG显著抑制体内生长， 人DU 145 PCa异种移植物在裸鼠中的生长，而对体重没有不利影响。在工作中， 我们的合作者Sung-Hoon Kim，PGG具有有效的抗血管生成活性， 在小鼠肺癌模型中的肿瘤效应。我们假设PGG通过抑制癌细胞增殖来预防PCa， 通过不同的G1和S期阻滞机制增殖，诱导p53依赖性和非依赖性 细胞凋亡和抑制血管生成。我们提出了五个具体目标来验证这些假设。 目标1.探讨PGG抑制DNA复制合成的机制及其在S期阻滞和细胞凋亡中的作用 重点在于DNA损伤/复制应激-检查点途径（例如，ATM/ATR，第53页）。目标2.到 研究细胞周期蛋白D1和Stat 3作为PGG抑制G1进展的靶点的作用，并验证G1-和S- 丝裂原激活的血管内皮细胞中的阻滞机制作为抗血管生成的机制之一 PGG的作用。目标3：检测ROS在细胞周期阻滞和凋亡中的作用及其亚细胞来源 信号传导并评估内在和外在胱天蛋白酶级联的贡献。在上面的牢房里 将使用培养模型、生物化学、药理学和遗传学方法来确定因果关系。 目标4。建立PGG对本地转基因小鼠的化学预防效果 原发性前列腺癌小鼠前列腺（TRAMP）模型。目标5。表征 化学预防功效的体内生物标志物，包括细胞增殖、细胞凋亡、血管生成和 PGG的分子靶标（例如，细胞周期蛋白D1、p-Stat 3、Bcl-2家族、VEGF）。 细胞培养研究（目标1-3）将提供对新机制的全面理解， PGG通过不同的细胞周期G1和S-阻滞的化学预防作用的靶点和途径， 前列腺癌细胞和血管内皮细胞中半胱天冬酶介导的细胞凋亡。动物研究（目标4）将测试 PGG抑制原发性前列腺癌发生，特别是预防或延迟发生的优点 雄激素非依赖性前列腺癌目标5中的生物标志物分析将有助于在体内识别和验证 PGG化学预防功效的相关分子靶点和途径。本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-没食子酰基-β- D-葡萄糖（PGG）用于前列腺癌（PCa）的化学预防，PCa是癌症死亡的第二大原因， 美国男人化学预防已被公认为是一种合理的和具有成本效益的替代方法， 降低PCa的发病率和死亡率。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阻滞， S期阻滞并诱导半胱天冬酶介导的凋亡。特别是，我们的初步数据支持一个强大的， PGG对不同雄激素依赖和p53的前列腺癌细胞DNA复制合成的快速抑制作用 作为主要的抗增殖机制。据我们所知，这还没有被描述为癌症 化学预防剂迄今为止研究。拟议的机制说明可能导致 建立了一种新的化学预防剂的新范例，不仅用于前列腺癌， 以及其他器官部位的癌症。这些多目标活动加上发表的支持反- 血管生成活性为测试PGG对前列腺癌的功效提供了强有力的理论基础 化学预防

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. 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.