转录因子GCF2通过PI3K/PTEN/Akt/mTOR通路影响肝癌增殖和凋亡的作用机制研究

GCF2(GC binding factor 2)是一个转录因子,通过结合下游基因的启动子GC丰富区抑制基因转录。我们前期研究证实GCF2在肝癌细胞过表达，下调GCF2表达可抑制肝癌细胞增殖、促进凋亡；同时，PTEN蛋白表达显著增加。因为PTEN与PI3K激酶起着相反作用。我们猜测，GCF2可能调控PI3K/PTEN/Akt/mTOR通路，进而影响肝癌增殖和凋亡。本研究拟在临床肝癌标本中检测GCF2与PTEN表达的相关性；在细胞和动物模型中，通过敲低GCF2蛋白表达和过表达等方法，研究GCF2对肝癌增殖、凋亡及PI3K/PTEN/Akt/mTOR通路影响，进一步，我们通过凝胶阻滞分析和荧光素酶报告基因验证PTEN是否为GCF2的靶基因？本研究有望明确GCF2对PTEN的调控关系，有助于揭示GCF2参与肝癌发生发展的作用机制，可为开展以GCF2为干预靶点的药物研究提供实验依据。

GC-binding factor 2(GCF2) is transcription factor that represses the activities of the genes enriching GC sequences in promoters. Our previous work has reported that knockdown of GCF2 by RNAi caused cell growth inhibition, increased apoptosis and PTEN protein expression in hepatocellular carcinoma (HCC) BEL-7404 and HepG2 cells. Since PTEN plays an important role on PI3K/PTEN/Akt/mTOR pathway, we conjecture that GCF2 may take part in the process of proliferation and apoptosis of HCC by PI3K/PTEN/Akt/mTOR signaling. Here we first analyze the protein expression of GCF2 and PTEN in tumor of HCC patients by immunohistochemistry. Then, the effect of GCF2 on cell proliferation, apoptosis and PI3K/PTEN/mTOR signaling is detected by knockdown or up-regulation GCF2 expression in HCC cell lines and tumor of SCID transplanted with HCC cells. Additionally, interreaction between GCF2 and the promoter of PTEN is evaluated through methods of gel retardation assasy and relative activity of luciferase. Thus, this research project may expoud the relationship between GCF2 and PTEN, provide a molecular mechanism of HCC, and give the experiment support that GCF2 may be a potential target for treating HCC.