下调SRGN基因表达对乳腺癌细胞凋亡及JAK/STAT信号通路的影响

Effect of down-regulation of SRGN gene on apoptosis and JAK/STAT signaling pathway in breast cancer cells

目的探讨小分子糖蛋白丝甘蛋白聚糖(SRGN)在乳腺癌细胞中的表达及下调其表达对细胞凋亡和JAK/STAT信号通路的影响。方法以正常乳腺上皮细胞MCF-10A为对照,采用Western blot检测乳腺癌细胞MDA-MB-231、SMMC-7721、MCF7、HCC1569中SRGN蛋白的表达水平。通过脂质体LipofectamineTM2000将SRGN si RNA转染MDA-MB-231细胞(si RNA-SRGN组),以si RNA-Con为阴性对照(si RNA-Con组),并设置空白对照组,收集转染48 h的细胞,Western blot检测各组细胞中SRGN、活化的含半胱氨酸的天冬氨酸蛋白水解酶3(cleaved caspase 3)以及JAK/STAT信号通路中磷酸化的蛋白酪氨酸激酶2(p-JAK2)和磷酸化的信号转导与转录因子3(p-STAT3)的表达水平;流式细胞仪检测各组细胞的凋亡率。结果乳腺癌细胞中SRGN蛋白的表达水平高于正常乳腺上皮细胞(P﹤0.05);si RNA-SRGN组的SRGN蛋白表达水平低于空白对照组(P﹤0.05);与空白对照组比较,si RNA-SRGN组的细胞凋亡率升高,cleaved caspase 3蛋白表达水平升高,p-JAK2和p-STAT3蛋白表达水平均下降,差异均有统计学意义(P﹤0.05)。结论 SRGN在乳腺癌细胞中的表达水平升高,通过RNA干扰抑制其表达后可诱导癌细胞凋亡,并下调JAK/STAT信号通路蛋白的表达水平。

Objective To investigate the effect of serglycin（SRGN） expression and down-regulation on apoptosis and JAK/STAT signaling pathway in breast cancer cells. Method Normal mammary epithelial cell line MCF-10 A was used as control, the expression of SRGN protein in MDA-MB-231, SMMC-7721, MCF7, HCC1569 breast cancer cells were detected by Western blot; SRGN siRNA（siRNA-SRGN group） and siRNA-Con（siRNA-Con group as negative control） were transfected into MDA-MB-231 cells by LipofectamineTM2000, and set the blank control group; cells were transfected for 48 h, the expression of SRGN, cleaved caspase 3, p-JAK2 and p-STAT3 protein were detected by Western blot; the apoptotic rate was detected by flow cytometry. Result Compared to MCF-10 A cells, the expression of SRGN in breast cancer cells were significantly higher（P〈0.05）; expression of SRGN protein in siRNA-SRGN group was significantly lower than that in blank control group（P〈0.05）; compared to the blank control group, the apoptosis rate and the expression of cleaved caspase 3 protein in siRNA-SRGN group increased significantly（P〈0.05）, and the expression of p-JAK2 and p-STAT3 protein decreased significantly（P〈0.05）. Conclusion The expression of SRGN is increased in breast cancer cells, inhibition of its expression by RNA interference can induce apoptosis of the cancer cells and down regulate the JAK/STAT signaling pathway.