Chemopreventive Signaling Mechanisms in Prostate Cancer

描述(申请人提供)：前列腺癌是美国男性最常见的恶性肿瘤，每年夺走约4万人的生命。转移性前列腺癌是不可治愈的，与平均2-3年的存活期有关。局限性前列腺癌向转移性和侵袭性疾病发展的特点是从前驱病变的出现到临床表现的潜伏期相对较长。为了减少前列腺癌的发病率，通过饮食和/或化学干预进行癌症化学预防将是一种合乎逻辑和实际的方法。最近，我们和其他人发现，众所周知的第2相基因诱导剂，包括十字花科蔬菜中的异硫氰酸酯(ITCs)(包括苯基异硫氰酸酯(PEITC)和萝卜硫醚(SFN))，以及众所周知的黄酮类核因子-kappaB抑制剂姜黄素，在体外和体内对各种人前列腺细胞株以及裸鼠体内都有很强的抑制作用。在这项题为“前列腺癌中化学预防药物的信号传递”的新应用中，我们将通过检验异硫氰酸酯和姜黄素单独和/或联合通过抑制细胞增殖和促进前列腺细胞凋亡来预防癌症发生的假设，重点讨论异硫氰酸酯单独或与酚类化合物姜黄素联合使用对癌症的抑制作用。我们将在体外细胞培养模型中检测异硫氰酸酯和姜黄素的剂量效应以及相关药物的代谢、分布、药代动力学和组织水平，体内抗癌机制和相关的分子机制。以下具体目标旨在解决我们的假设。1.检测和建立PEITC和姜黄素单独或联合应用对裸鼠PC-3肿瘤移植瘤的作用。我们将研究不同剂量的PEITC和姜黄素单独或联合短期和长期治疗对细胞增殖和肿瘤进展的抑制作用。2.观察和建立PEITC和姜黄素单独或联合应用对TRAMP小鼠模型的影响。我们将研究不同剂量的PEITC和姜黄素单独或联合长期治疗对细胞增殖和肿瘤进展的抑制作用。3.研究PEITC和姜黄素单独或联合应用对裸鼠和裸鼠的体内抑癌作用机制。我们将在裸鼠和TRAMP小鼠的短期和长期实验中，研究PEITC和姜黄素单独或联合应用对细胞增殖和肿瘤进展的抑制作用是否与相关信号通路(如核因子-KB、AKT、MAPK)的活性有关。4.深入研究PEITC和姜黄素单独或联合诱导前列腺癌细胞生长抑制和凋亡的信号通路，包括IKKS-NF-KB、生长因子/酪氨酸激酶-AKT通路和MAPK-caspase-凋亡通路的作用。我们的长期目标是阐明PEITC和姜黄素单独或联合抑制前列腺癌发生的机制，并确定其化学预防作用的分子靶点。这些知识将有助于开发更好的化学预防化合物，并设计更有效的前列腺癌化学预防临床试验。

DESCRIPTION (provided by applicant): Prostate Cancer is the most common malignancy in American men claiming about 40,000 lives per year. Metastatic prostate cancer is not curable and is associated with a mean survival of 2-3 years. The progression of localized prostate cancer to metastatic and invasive disease is often characterized by a relatively long latency from the occurrence of precursor lesions to the manifestation of clinical disease. To decrease the incidence of prostate cancer, cancer chemoprevention through dietary and/or chemical intervention would be a logical and practical approach. Recently, we as well as others have found that the well known Phase 2 gene inducers, isothiocyanates (ITCs) including phenethylisothiocyanate (PEITC) and sulforaphane (SFN) that are present in cruciferous vegetables, and curcumin, the well known flavonoid NF-kappaB inhibitor that is present in tumeric powdered food preparation, have potent inhibitory effects in various human prostatic cell lines in vitro as well as in vivo in athymic nude mice. In this new application entitled "Signaling of Chemopreventive Agents in Prostate Cancer", we will focus on the effects of isothiocyanates alone or in combination with the phenolic compounds curcumin, on the inhibition of carcinogenesis by testing the hypothesis that isothiocyanate and curcumin alone and/or in combination prevent carcinogenesis by inhibiting cellular proliferation and enhancing apoptosis in the prostate. We will examine the dose-response of the isothiocyanate and curcumin and the related metabolism, distribution, pharmacokinetics and tissue levels of the drugs, the in vivo anti-carcinogenesis mechanism and the related molecular mechanisms in the in vitro cell culture models. The following specific aims are designed to address our hypothesis. 1 .To examine and establish the effect of PEITC and curcumin, alone or in combination in Nude mice PC-3 tumor xenografts. We will study the inhibition of cell proliferation and tumor progression by different doses of PEITC and curcumin alone or in combination in short-term as well as in long-term treatments. 2. To investigate and establish the effect of PEITC and curcumin alone or in combination in the TRAMP mice model. We will investigate the inhibition of cell proliferation and tumor progression by different doses of PEITC and curcumin alone or and in combination, in long-term treatments. 3. Examine the in vivo mechanisms of inhibition of carcinogenesis by PEITC and curcumin alone or in combination in nude mice and in TRAMP mice. We will study whether the inhibition of cell proliferation and tumor progression by PEITC and curcumin alone or in combination described in Aims 1 and 2, could be related to the activity of pertinent signaling pathways (e.g., NF-KB, AKT, MAPK) in short- and long-term Nude mice and TRAMP mice experiments. 4. Elucidate in-depth mechanistic studies in prostate cancer cell lines on the signaling pathways leading to growth inhibition and apoptosis induced by PEITC and curcumin alone or in combination including the role of IKKs-NF-KB, growth factors/tyrosine kinase-AKT pathways, and the MAPK-caspase-apoptosis pathways. Our long-term goal is to elucidate the mechanisms of inhibition of prostate carcinogenesis by PEITC and curcumin alone or in combination, and to identify the molecular targets of their chemopreventive effects. Such knowledge will help to develop better chemopreventive compounds and to design more effective cancer chemoprevention clinical trials in prostate cancer.