GPAT3在肝癌发生发展中的作用及机制研究

Under the support of the previous National Natural Science Foundation, we carried out a deep study on D4S2964 locus in hepatocellular carcinoma (HCC) tissues. The frequent gene copy number gains and mRNA/protein over-expression of GPAT3 gene, which located at the edge of locus D4S2964, were found in HCC tissues, and were significantly correlated with poor prognosis of patients. In our preliminary experiments, knock-down of GPAT3 could effectively inhibit HCC cell growth, induce cell apoptosis and blockade mTOR signaling. Based on these results, we suppose that GPAT3 might be a novel candidate tumor suppressor gene for HCC. This study will evaluate the expression level of GPAT3 in large cohorts of samples of HCCs, and retrospectively analyzed with clinical and follow-up data, with aim to elucidate its clinical significance; develop inducible and liver-specific GPAT3-knockout transgenic mice for evaluation of chemically induced HCC in mice, in order to explore the functions of GPAT3 in HCC oncogenesis; construct stable cell lines over-expressing and down-expressing GPAT3 to observe the influence of GPAT3 on HCC cell biological behaviors and tumor formation, development and metastasis in vitro and in vivo, with emphasis on the mechanism by which GPAT3 and its produced catalysate regulate mTOR or other signal pathway. This study will help to elucidate the pathogenesis of HCC and provide a brand new biomarker for prognosis prediction and target treatment of HCC.

本课题组在前期国自然基金的资助下，开展了肝癌4号染色体D4S2964位点的研究，发现其远端的GPAT3基因DNA拷贝数增加且mRNA和蛋白表达升高，而后者与肝癌预后差相关；预实验结果显示下调GPAT3可抑制肝癌细胞生长、诱导凋亡并能够抑制mTOR通路活性。据此，我们假测GPAT3是一个肝癌相关的候选癌基因。本项目拟通过检测GPAT3在大样本肝癌中的表达水平，结合临床和随访资料进行分析，以明确其在肝癌临床中的作用和意义；构建肝脏特异性可诱导型GPAT3转基因鼠并辅以化学诱癌，以研究其在肝癌发生中的作用；建立GPAT3上调和下调的细胞株，采用体内和体外模型以探讨其在肝癌中的细胞生物学功能及在肝癌发生、形成与转移中的作用，重点将研究该基因及其催化产物调控mTOR信号通路或其他信号通路的详细机制。本项目的实施将有助于阐明肝癌的发病分子机理，并为肝癌临床提供一个潜在的预后标志物和靶向治疗的靶点分子。