SIRPα对乳腺癌细胞MDA-MB-231黏附、侵袭和凋亡的影响

Influence of signal regulatory protein α on adhesion,invasion and apoptosis of breast cancer cell line MDA-MB-231

目的:研究信号调节蛋白α(signal regulatory protein α,SIRPα)对乳腺癌细胞黏附、侵袭和凋亡的影响及其可能机制。方法:Western blotting检测侵袭能力强的MDA-MB-231乳腺癌细胞和侵袭能力弱的MDA-MB-435乳腺癌细胞中SIRPα蛋白的表达。脂质体法将pcDNA3.0-SIRPα转染MDA-MB-231细胞后,RT-PCR检测MDA-MB-231细胞SIRPαmRNA的表达,TUNEL法检测细胞的凋亡,细胞侵袭实验观察细胞侵袭能力变化,黏附实验观察细胞黏附能力变化,Westernblotting检测JNK和p-JNK蛋白的表达。EGF刺激MDA-MB-435细胞,免疫共沉淀检测MDA-MB-435细胞中SIRPα与SHP2的结合。结果:侵袭能力强的MDA-MB-231细胞不表达SIRPα,侵袭能力弱的MDA-MB-435细胞表达高水平SIRPα蛋白。pcDNA3.0-SIRPα转染可增强MDA-MB-231细胞的黏附,降低MDA-MB-231细胞的侵袭能力,并促进MDA-MB-231细胞的凋亡。pcDNA3.0-SIRPα转染抑制MDA-MB-231细胞JNK的磷酸化。EGF刺激可进一步上调MDA-MB-435细胞中SIRPα蛋白表达,并促进SIRPα与SHP-2蛋白的结合。结论:SIRPα与乳腺癌细胞的黏附、侵袭能力相关,并可能通过抑制JNK磷酸化促进乳腺癌细胞凋亡。

Objective：To observe the effects of signal regulatory protein α （SIRPα） on the adhesion,invasion and apoptosis of human breast cancer cells,and to explore the possible mechanism.Methods： SIRPα protein expression in high invasion breast cancer MDA-MB-231 cells and low invasion breast cancer MDA-MB-435 cells were detected by Western blotting analysis.pcDNA3.0-SIRPα plasmid was transfected into MDA-MB-231 cells by lipofectant assay,and SIRPα mRNA expression was examined by RT-PCR.Apoptosis of cells was examined by TUNEL method; invasion and adhesion abilities of MDA-MB-231 cells were examined by invasion or adhesion assays; and JNK and p-JNK protein expressions were determined by Western blotting analysis.Interaction of SIRPα with SHP2 in MDA-MB-435 cells stimulated with EGF was determined by immunoprecipitation assay.Results： Highly invasive MDA-MB-231 cells did not express SIRPα,while lowly invasive MDA-MB-435 cells expressed high level of SIRPα protein.pcDNA3.0-SIRPα transfection enhanced the adhesion of MDA-MB-231 cells,decreased their invasion ability,and promoted their apoptosis.Phosphorylation of JNK in pcDNA3.0-SIRPα transfected MDA-MB-231 cells was also decreased.EGF stimulation further increased SIRPα protein expression in MDA-MB-435 cells and enhanced the interaction of SIRPα with SHP2.Conclusion： SIRPα is related to adhesion and invasion of breast cancer cells,and might promote their apoptosis by decreasing the phosphorylation of JNK.