HEPATIC OVAL CELLS IN CULTURE AND IN VIVO

描述（申请人提供）：肝内胆管癌是高发病率和死亡率的高度恶性腺癌，治疗方案有限。在之前的资助期间，我们获得了初步数据，支持建立一种独特的肝内胆管癌快速生长和进展的临床前大鼠模型，该模型概括了人类疾病的临床以及关键的细胞和分子特征。最值得注意的是，我们通过该模型，将突变激活的ErbB-2/Neu转化的大鼠胆管细胞原位移植到等基因大鼠肝脏中，发现胆管阻塞与肿瘤生长增强之间存在正相关关系，提示一种新的重要的生长调节机制，可能作为一种与人类胆管癌生长进展相关的新型促进刺激具有重要意义。我们之前的工作也证明了在胆管癌中ErbB-2/Neu过表达和环氧合酶-2上调之间的联系，支持这些分子途径在胆管癌发生中的重要作用。最近，我们首次实现了大鼠胆管细胞的自发肿瘤移植，发现这与环氧化酶-2的显著上调以及Akt的显著激活有关，但令人惊讶的是，与ErbB-2/Neu表达或信号传导增强无关。有趣的是，与同样过表达环氧化酶-2的ErbB-2/ new转化体相比，这些自发转化的胆管细胞仅具有中等致瘤性。我们现在建议扩展我们的初步发现：(1)探索胆管梗阻后胆管癌生长改变的机制和调节因素，以及采用最先进的分子和定量免疫组织化学技术的基因表达谱，以提供我们独特的肿瘤大鼠胆管细胞系之间差异的全面图片及其体外和体内生长反应；(2)阐明环氧化酶-2上调与Akt活化在大鼠胆管细胞体外自发转化中的功能调控关系，以及HGF和TGF-？促进这些细胞的恶性潜能。该研究具有重要意义，因为它将建立一个强大的胆管癌新模型，对靶向治疗的临床前测试具有重要价值。

DESCRIPTION (provided by applicant): Intrahepatic cholangiocarcinomas are highly malignant adenocarcinomas with high morbidity and mortality rates, and limited treatment options. During the previous grant period, we obtained preliminary data supporting the establishment of a unique preclinical rat model of rapid intrahepatic cholangiocarcinoma growth and progression that recapitulates clinical as well as key cellular and molecular features of the human disease. Most notably, we identified with this model, based on orthotopic cell transplantation of mutationally-activated ErbB-2/Neu transformed rat cholangiocytes into the livers of isogenic rats, a positive correlation between bile duct obstruction and enhanced tumor growth, suggesting a new and important growth regulatory mechanism that may have great significance as a novel promoting stimulus relevant to human cholangiocarcinoma growth and progression. Our previous work also demonstrated a link between ErbB-2/Neu overexpression and cyclooxygenase-2 up-regulation in cholangiocarcinoma, supporting an important role for these molecular pathways in cholangiocarcinogenesis. Even more recently, we achieved for the first time spontaneous neoplastic transplantation of rat cholangiocytes, which was found to be associated with a significant up-regulation of cyclooxygenase-2 together with prominent activation of Akt, but surprisingly not with enhanced ErbB-2/Neu expression or signaling. Interestingly, these spontaneously transformed cholangiocytes were only intermediately tumorigenic when compared with ErbB-2/Neu transformants that also overexpressed cyclooxygenase-2. We now propose to extend our preliminary findings by (1) exploring mechanisms and regulators of altered cholangiocarcinoma growth following bile duct obstruction, as well as employing state-of-the art molecular and quantitative immunohistochemical technologies of gene expression profiling to provide a comprehensive picture of the differences among our unique neoplastic rat cholangiocyte cell lines and their growth responses in vitro and in vivo, and (2) elucidate the functional regulatory relationships between cyclooxygenase-2 up-regulation and Akt activation in in vitro spontaneous transformation of rat cholangiocytes, and the role played by HGF and TGF-? in promoting the malignant potential of these cells. The proposed research is highly significant since it will establish a powerful new model of cholangiocarcinoma that can be of great value for preclinical testing of target based therapies.