PI3K／AKT／mTOR信号传导通路在姜黄素抑制人肝癌细胞Cox-2表达中的作用

Role of PI3K/AKT/mTOR pathway in the expression of Cox-2 in inhibition of human hepatocellular carcinoma cells by curcumin

目的探讨MAPK和PI3K信号传导通路在姜黄素调节的环氧合酶2(Cox-2)表达中的作用。方法分别加入25、50μmol/L LY294002,10、20μmol/L U0126,5、10ng/ml西罗莫司(雷帕霉素,rapamycin)处理人肝癌细胞BEL-7402,30min后加入10μmol/L姜黄素,对照组单独加入0、10μmol/L姜黄素,培养6h后,采用RT-PCR和Western blotting方法检测BEL-7402细胞中Cox-2 mRNA和蛋白的表达。以不同浓度(0、2.5、5、10、15、20μmol/L)姜黄素或25μmol/L LY294002处理BEL-7402细胞,培养6h后,采用Western blotting检测总AKT蛋白和磷酸化AKT蛋白的表达;以不同浓度(0、2.5、5、10、15、20μmol/L)姜黄素或10μmol/L U0126处理BEL-7402细胞,培养6h后,采用Western blotting检测总ERK蛋白和磷酸化ERK蛋白的表达。结果与仅加入10μmol/L姜黄素的BEL-7402细胞比较,分别加入25、50μmol/L LY294002,5、10ng/ml西罗莫司后,BEL-7402细胞中的Cox-2 mRNA和蛋白表达均明显降低,差异有统计学意义(P<0.01),而加入10、20μmol/L U0126后表达无明显变化(P>0.05)。采用不同浓度姜黄素或25μmol/L LY294002处理后,BEL-7402细胞磷酸化AKT蛋白表达逐渐降低,与对照组相比差异有统计学意义(P<0.01),但总AKT蛋白表达与对照组相比无明显变化(P>0.05)。不同浓度姜黄素或10μmol/L U0126处理后,BEL-7402细胞磷酸化ERK蛋白和总ERK蛋白表达与对照组相比均无明显变化(P>0.05)。结论姜黄素可能通过PI3K/AKT/mTOR信号传导通路抑制人肝癌细胞BEL-7402中Cox-2的表达。

Objective To investigate the roles of MAPK and PI3K signal transduction pathway in the expression of Cox-2 regulated by curcumin in human hepatocellular carcinoma BEL-7402 ceils. Methods BEL-7402 cells were pretreated with 20 or 50μmol/L of LY294002, 10 or 20μmol/L of U0126, and 5 or 10ng/ml of rapamycin for 30 minutes, followed by treatment with 10μmol/L of curcumin. The BEL-7402 cells in control group were treated with 0 or 10μmol/L of curcumin alone. After being cultured for 6 hours, the expression of Cox-2 mRNA and protein were determined by RT-PCR and Western blotting. BEL-7402 cells were treated with different concentrations of curcumin （0, 2.5, 5, 10, 15, 20lxmol/L） or 25pomol/L of LY294002 for 6 hours, and phosphorylated AKT and total AKT were detected by Western blotting. BEL-7402 ceils were treated with different concentrations of curcumin （0, 2.5, 5, 10, 15, 20μmol/L） or 10 txmol/L ofU0126 for 6 hours, then the phosphorylated ERK and total ERK were also assessed by Western blotting. Results Compared with the BEL-7402 cells treated with 10μmol/L curcumin alone, the expression of Cox-2 mRNA and protein decreased significantly in the BEL-7402 cells treated with 25, 50μmol/L of LY294002, and 5, 10ng/ml of rapamycin respectively （P〈0.01）, but no difference was found when 10 or 20μmol/L of U0126 was added （P〉0.05）. Compared with control group, the expression of phosphorylated AKT protein decreased gradually in BEL-7402 cells treated with different concentrations of curcumin or 251xmol/L of LY294002 （P〈0.01）, but there was no significant difference in the expression of total AKT protein （P〉0.05）. There was no significant difference in the expression ofphosphorylated ERK protein and total ERK protein in BEL-7402 cells treated with different concentrations ofcurcumin or 10μmol/L ofU0126 （P〉0.05）. Conclusion Curcumin may inhibit the expression of Cox-2 in human hepatocellular carcinoma BEL-7402 cells through PI3K/AKT/mTOR signal transduction pathway.