Anti-carcinogenic effects of White Tea on Lung Cancer

描述(由申请人提供)：该R21项目的最终目标是评估白茶提取物(WTE)在肺癌化学预防中的潜力。虽然大多数评价茶的抗肿瘤作用的工作都是针对绿茶进行的，但白茶的潜在健康益处及其相对于绿茶的优势正得到越来越多的认识。因此，我们假设白茶提取物可以有利地调节与肺癌发生相关的机制，并可能对肺癌的化学预防有用。具体目的1：评价WTE对肺癌的抗癌作用。目的：研究WTE诱导非小细胞肺癌(NSCLC)细胞凋亡的作用，进一步探讨WTE诱导细胞凋亡的分子机制。特定目的1.1B：在体外肺癌发生模型中，确定WTE在诱导细胞凋亡中的作用。通过比较有条件的非小细胞肺癌(NSCLC)细胞系和正常的人支气管上皮(NHBE)细胞，将确定不同剂量WTE对细胞凋亡的不同影响。为了探索WTE在预防恶性转化方面的潜力，将使用肺癌发生的体外模型进行类似的实验，该模型由暴露于肺癌致癌物的BEAS-2B细胞组成。WTE通过增加15-HETE的产生来激活PPAR-1，从而诱导肿瘤细胞(包括癌前支气管上皮细胞系1198)凋亡的能力将被确定。具体目的1.2：评价WTE对NSCLC、BEAS-2B、1198和NHBE细胞中肿瘤相关、通路特异性基因表达的差异。除了诱导细胞凋亡外，WTE还可能有利地调节多种致癌机制。我们将使用癌症路径探索器实时定量聚合酶链式反应阵列来检测WTE在这些细胞中癌症相关、路径特异性基因表达的差异变化。特异目的1.3：评价WTE对NSCLC、BEAS-2B、1198和NHBE细胞中caspase3活性的影响。具体目的2：在体外肺微环境模型上，评价黄连提取物对花生四烯酸代谢及PPAR信号通路的影响。为了了解WTE是否会介导肺微环境的变化，可能有助于预防肺癌，将使用由人支气管肺泡灌洗(BAL)细胞与NSCLC或NHBE或1198或BEAS-2B细胞组成的共培养系统的代理模型。将评估WTE对共培养中花生四烯酸代谢和PPAR激活的不同影响。具体目标3：评估EGCG在我们的模型系统中的稳定性和新陈代谢，以确保WTE诱导的抗肿瘤作用不是由于体外“人工制品”。这项拟议的研究结果将为研究WTE在肺部的抗肿瘤特性提供重要的见解，并确定潜在的替代终点生物标记物，用于监测未来WTE用于肺癌化学预防试验的有效性。 公共卫生相关性：肺癌是我国癌症死亡的主要原因，超过结直肠癌、乳腺癌和前列腺癌造成的死亡总和；由于预后糟糕，迫切需要安全、有效的肺癌化学预防策略。本R21的应用目的是评价白茶提取物(WTE)对肺癌的抗癌作用，使用多种体外模型系统模拟肺癌发生的不同阶段，以及肺微环境。这一临床前应用的结果将为WTE在肺部的抗肿瘤特性提供新的、重要的见解，并为临床试验确定WTE在未来肺癌化学预防中的可行性和有效性奠定基础。

DESCRIPTION (provided by applicant): The ultimate goal of this R21 project is to evaluate the potential of white tea extract (WTE) for lung cancer chemoprevention. Whereas most of the work evaluating the anti-neoplastic effects of tea has been done on green tea, the potential health benefits of white tea and its advantage over green tea are becoming increasingly recognized. We therefore hypothesize that white tea extract can favorably modulate mechanisms associated with lung tumorigenesis, and may be useful for lung cancer chemoprevention. Specific Aim 1: To evaluate the anticarcinogenic effects of WTE against lung cancer. Specific Aim 1.1A: To examine effects of WTE on the induction of apoptosis in nonsmall cell lung cancer (NSCLC) and to further characterize the molecular mechanisms responsible for the WTE-induced apoptotic cell death. Specific Aim 1.1B: To determine the effects of WTE on the induction of apoptosis in an in vitro model of lung carcinogenesis. The differential effects of varying doses of WTE on apoptosis will be determined by comparing conditioned nonsmall cell lung cancer (NSCLC) cell lines to normal human bronchial epithelial (NHBE) cells. To explore the potential of WTE on preventing malignant transformation, similar experiments will be carried out using an in vitro model of lung carcinogenesis, comprised of BEAS-2B cells exposed to lung carcinogens. The ability of WTE to induce apoptosis in neoplastic cells (including 1198, a premalignant bronchial epithelial cell line) through activating PPAR- via an increase in 15-HETE production will be ascertained. Specific Aim 1.2: To evaluate the differential effects of WTE on cancer-relevant, pathway specific gene expression in NSCLC, BEAS-2B, 1198, and NHBE cells. In addition to inducing apoptosis, WTE may also favorably modulating multiple carcinogenic mechanisms. We will use Cancer PathwayFinder real time PCR array to detect differential alterations in cancer relevant, pathway specific gene expression by WTE in these cells. Specific Aim 1.3: To evaluate the differential effects of WTE on caspase 3 activities in NSCLC, BEAS-2B, 1198 and NHBE cells. Specific Aim 2: To evaluate the effects of WTE on arachidonic acid metabolism and PPAR- signaling pathway in an in vitro model of the lung microenvironment. To see if WTE will mediate changes in the lung microenvironment that may help prevent lung cancer, a surrogate model using coculture systems comprised of human bronchoalveolar lavage (BAL) cells with either NSCLC or NHBE, or 1198 or BEAS-2B cells will be used. The differential effects of WTE on arachidonic acid metabolism and PPAR- activation in the co-cultures will be assessed. Specific Aim 3: To evaluate the stability and metabolism of EGCG in our model systems to ensure that WTE-induced antineoplastic effects are not due to in vitro "artifacts." The findings of this proposed study will provide important insights into the anti-neoplastic properties of WTE in the lungs, and identify potential surrogate endpoint biomarkers for monitoring the efficacy of lung cancer chemoprevention trials with WTE in the future. PUBLIC HEALTH RELEVANCE: Lung cancer is the leading cause of cancer death in this country, surpassing deaths caused by colorectal, breast and prostate cancers combined; because of the dismal prognosis, safe, efficacious chemopreventive strategy for lung cancer is urgently needed. The purpose of this R21 application is to evaluate the anti- carcinogenic effects of white tea extract (WTE) on lung cancer, using a variety of in vitro model systems to simulate different stages of lung carcinogenesis, as well as the lung microenvironment. The findings of this preclinical application will provide novel, important insights into the anti-neoplastic properties of WTE in the lungs, and set the stage for clinical trials to determine the feasibility and efficacy of WTE for lung cancer chemoprevention in the future.