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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 investigate the effect of signal regulatory protein α (SIRPα) on the adhesion, invasion and apoptosis of breast cancer cells and its possible mechanism. Methods: Western blotting was used to detect the expression of SIRPα in MDA-MB-231 breast cancer cells with strong invasiveness and MDA-MB-435 breast cancer cells with weak invasiveness. The expression of SIRPαmRNA in MDA-MB-231 cells was detected by RT-PCR and the apoptosis of MDA-MB-231 cells was detected by lipofectamine. The changes of cell invasiveness were observed by cell invasion assay , Adhesion experiments were observed changes in cell adhesion capacity, Western blotting detection of JNK and p-JNK protein expression. EGF-stimulated MDA-MB-435 cells were co-immunoprecipitated to detect the binding of SIRPα to SHP2 in MDA-MB-435 cells. Results: MDA-MB-435 cells with high invasiveness did not express SIRPα and MDA-MB-435 cells with low invasiveness expressed high levels of SIRPα protein. Transfection with pcDNA3.0-SIRPα enhanced the adhesion of MDA-MB-231 cells, decreased the invasiveness of MDA-MB-231 cells and promoted the apoptosis of MDA-MB-231 cells. Transfection of pcDNA3.0-SIRPα inhibits phosphorylation of JNK in MDA-MB-231 cells. EGF stimulation can further up-regulate SIRPα protein expression in MDA-MB-435 cells and promote the binding of SIRPα to SHP-2 protein. Conclusion: SIRPα is associated with adhesion and invasion of breast cancer cells and may promote breast cancer cell apoptosis by inhibiting JNK phosphorylation.