A novel mouse prostate carcinogenesis model for dietary cancer prevention researc

描述(申请人提供)：本项目的目标是利用hCYP1A小鼠和PhIP建立一种新的前列腺癌模型，表征致癌的分子变化，并确定富含生育酚(-T)的生育酚混合物(-TMT)对前列腺癌的预防活性，与-T不同，TMT是一种更有效的化学预防药物。这些假说是：1)PhIP通过引起DNA加合物的突变形成并伴随氧化应激和炎症而导致前列腺癌的发生；2)高脂饮食(HFD)可以促进前列腺癌的发生，缩短实验周期；3)-TMT通过其抗氧化和抗炎作用以及抑制致癌信号通路而抑制前列腺癌的发生。具体目标如下：目的1.建立PhIP诱导的hCYP1A小鼠前列腺癌模型，并对其细胞/分子变化进行研究。将PhIP(200 mg/kg，po)给以AIN76A饮食维持的雄性hCYP1A小鼠；然后将它们保持在AIN76A饮食或HFD(含20%脂肪)饮食中。在20周、30周、40周和50周将监测前列腺病变和癌症的发展。采用免疫组织化学方法(IHC)检测细胞增殖(Ki67和增殖细胞核抗原)、细胞凋亡(裂解caspase-3和TUNEL)、炎症(核因子-kB和CD45)、氧化应激(8-OHdG和-H_2AX)及GSTP1、E-cadherin、COX-2、p63、p27、Pten、Nkx3.1、p16和Bcl2的表达。在开发更快的模型的过程中，我们还可以检验HFD促进前列腺癌发生的假设。此外，还将探讨在饮食中添加PhIP对前列腺癌的诱导作用。目的2.测定生育酚预防前列腺癌的活性。将经PhIP处理的hCYP1A小鼠置于HFD或HFD加-TMT的治疗下。-TMT预计将减少前列腺中的氧化和亚硝化压力和炎症以及致癌信号，并防止或推迟PIN病变和前列腺癌的发生。影响：这项研究将通过以下方面对前列腺癌研究产生影响：1)开发一种新的相关模型来研究饮食因素和前列腺癌；2)评估高脂肪饮食是一种危险因素；以及3)确定TMT作为前列腺癌的化学预防药物。

DESCRIPTION (provided by applicant): The objectives of this project are to develop a novel prostate cancer model using hCYP1A mice and PhIP, to characterize the molecular changes of carcinogenesis, and to determine the prostate cancer preventive activity of a -tocopherol (-T) rich mixture of tocopherols (-TmT) which, unlike -T, is a more effective chemopreventive agent. The hypotheses are: 1) PhIP induces prostate carcinogenesis by causing mutagenic DNA-adduct formation accompanied by oxidative stress and inflammation, 2) a high-fat diet (HFD) can promote carcinogenesis, shortening the experimental period; and 3) -TmT can inhibit prostate carcinogenesis due to its antioxidant and anti-inflammatory actions as well as its inhibition of oncogenic signaling pathways. The specific aims are as follows: Aim 1. Develop the PhIP-induced prostate cancer model in hCYP1A mice and characterize the cellular/molecular changes involved. PhIP will be administered (200mg/kg, po) to male hCYP1A mice maintained on the AIN76A diet; then they will be kept either on AIN76A diet or the HFD (containing 20% fat). The development of prostate lesions and cancer will be monitored at 20, 30, 40, and 50 weeks. We will analyze the development of PIN and carcinoma in the prostate as well as determine the levels of cell proliferation (Ki67 and PCNA), apoptosis (cleaved caspase-3 and TUNEL), inflammation (NF-kB and CD45), and oxidative stress (8-OHdG and -H2AX), as well as the expression of GSTP1, E-cadherin, COX-2, p63, p27, Pten, Nkx3.1, p16, and Bcl-2 by immunohistochemistry (IHC). In the development of a faster model, we can also test the hypothesis that HFD promotes prostate carcinogenesis. The induction of prostate cancer by PhIP added to the diet will also be explored. Aim 2. Determine the prostate cancer preventive activity of tocopherols. The PhIP-treated hCYP1A mice will be put on the HFD or HFD supplemented with -TmT. -TmT is expected to decrease oxidative and nitrosative stress and inflammation as well as oncogenic signaling in the prostate, and prevents or delays the onset of PIN lesions and prostate carcinoma. Impact: This research will make an impact in prostate cancer research by 1) developing a novel and relevant model to study dietary factors and prostate cancer; 2) evaluating high fat diet as a risk factor; and 3) determining -TmT as a chemopreventive agent for prostate cancer.