茶氨酸溴香酰胺对人肝癌细胞体内外生长的抑制作用

以L-茶氨酸作对照，评估本实验室合成的新颖的茶氨酸衍生物-茶氨酸溴香酰胺（TBrC）对人肝癌HepG2细胞系体内外生长的抑制作用，并初步探究其作用的分子机制。采用MTT法检测不同浓度的TBrC对HepG2细胞体外生长的影响，应用蛋白质印迹法检测解析HepG2细胞中与癌细胞凋亡和生长密切相关蛋白的表达和药物可能作用的分子靶点。此外，建立动物肿瘤模型，与对照组茶氨酸和临床常用抗癌药物五氟尿嘧啶组相比较，评价TBrC对荷瘤裸鼠人肝癌HepG2肿瘤生长的抑制效果。实验结果显示，TBrC抑制人肝癌细胞体内外生长的活性超过其母体化合物茶氨酸分别为3倍和4倍以上，对小鼠生长无明显毒性。TBrC比茶氨酸更显著地抑制肝癌细胞生长因子受体c-Met和抗凋亡的Bcl-2等蛋白的表达；此外，TBrC大大上调促进凋亡的Bax蛋白的表达。TBrC抑制c-Met信号传导通路，下调Bcl-2/Bax蛋白比率可能是其作用的分子机制之一。这些结果提示，TBrC具有广泛应用于临床治疗和（或）辅助治疗人肝癌和其他癌症的潜力。

Inhibitory effects of TBrC against in vitro and in vivo growth of human hepatoma cells

The purpose of this study is to investigate the inhibitory effects of TBrC, a new synthesized theanine derivative on the in vitro and in vivo growth of human hepatoma HepG2 cells and the molecular mechanisms of action. The MTT assays were used to evaluate the effects of TBrC on the in vitro growth of human hepatoma cells. Western blotting was employed to analyze the protein expressions and the possible targets of action related to the growth inhibition and apoptosis in the human hepatoma cells treated with TBrC. In addition, an animal hepatoma model was established to assess the inhibitory effects of TBrC on the HepG2 human hepatoma growth in tumor-bearing nude mice. The experimental results show that TBrC enhance the in vitro and in vivo growth inhibition of the human HepG2 hepatoma cells and tumors by more than 4-fold and 3-fold, respectively as compared with its parental compound, theanine without detectable toxicity to the mice. TBrC reduces the expressions of c-Met receptor and antiapoptotic Bcl-2 protein as well as increases the expression of Bax protein in the human hepatoma cells. The molecular mechanism of TBrC action may be related to its suppression of the signaling pathway of c-Met and reduction of the Bcl - 2 / Bax ratio. All these results suggest that the new synthesized TBrC may have the wide therapeutic and/or adjuvant therapeutic application in the treatment of human hepatoma and other cancers.