Galectin-9调控SHH信号通路影响结直肠癌HT29细胞凋亡

Galectin-9 regulates SHH signaling pathway to influence apoptosis of colorectal cancer HT29 cells

目的:探讨半乳糖凝集素9(galectin-9)对结直肠癌细胞凋亡的影响及机制。方法:在结直肠癌细胞系HT29中分别转染galectin-9过表达载体pcDNA3.1-Galectin-9和对照载体pcDNA3.1,用real-time PCR和Western blot检测过表达效果。Annexin V-FITC/PI双染法检测细胞凋亡变化,Western blot测定细胞中活化的caspase-3水平,以及SHH信号通路蛋白Smo、Gli1和SHH的表达变化。用SHH信号通路特异性抑制剂cyclopamine处理上调galectin-9表达的结直肠癌细胞,用上述方法检测细胞凋亡、细胞中活化的caspase-3水平,以及SHH信号通路蛋白Smo、Gli1和SHH的表达变化。结果:pcDNA3.1-Galectin-9可显著上调结直肠癌HT29细胞中galectin-9的mRNA和蛋白水平。上调galectin-9表达后的结直肠癌HT29细胞凋亡率升高,细胞中活化的caspase-3蛋白水平升高,同时细胞中SHH信号通路蛋白Smo、Gli1和SHH的表达水平降低(P<0.05)。Cyclopamine处理可以进一步诱导上调galectin-9表达的结直肠癌HT29细胞凋亡,促进细胞中活化的caspase-3蛋白水平上调,降低细胞中SHH信号通路的激活水平(P<0.05)。结论:Galectin-9通过抑制SHH信号通路诱导结直肠癌HT29细胞凋亡。

AIM: To investigate the effect of galectin-9 on the apoptosis of colorectal cancer HT29 cells. METHODS: Galectin-9 over-expression vector(pcDNA3.1-Galectin-9) or control vector(pcDNA3.1) was transfected into the HT29 cells. The galectin-9 over-expression was detected by real-time PCR and Western blot. Annexin V-FITC/PI double staining was used to detect the apoptosis. The protein level of activated caspase-3 and the expression of SHH signaling pathway-related proteins Smo, Gli1 and SHH in the HT29 cells were determined by Western blot. SHH signaling pathway specific inhibitor cyclopamine was used to treat the HT29 cells with up-regulated galectin-9 expression, and the apoptosis, the protein level of cleaved caspase-3 and the expression of SHH signaling pathway-related proteins Smo, Gli1 and SHH in the HT29 cells were detected by the above methods. RESULTS: Transfection with pcDNA3.1-Galectin-9 up-regulated galectin-9 expression at mRNA and protein levels in the colorectal cancer HT29 cells(P<0.05). The apoptotic rate of the HT29 cells was increased after galectin-9 up-regulation. The protein level of cleaved caspase-3 in the cells was increased, while the expression levels of SHH signaling pathway-related proteins Smo, Gli1 and SHH were decreased. Cyclopamine treatment further induced the apoptosis of the HT29 cells with up-regulation of galectin-9, increased the protein le-vels of cleaved caspase-3, and decreased the activation level of SHH signaling pathway in the HT29 cells(P<0.05). CONCLUSION: Galectin-9 induces the apoptosis of colorectal cancer HT29 cells by inhibiting SHH signaling pathway.