DBC2基因诱导乳腺癌细胞周期G_1期阻滞的机制

Mechanisms of DBC2 Inducing the Cell Cycle G_1 Arrest in Breast Cancer Cell Line

目的研究肿瘤抑癌基因DBC2(deletion in breast cancer2)抑制乳腺癌MDA-MB-435S细胞增殖的可能机制。方法野生型DBC2基因的真核表达载体pEBG-DBC2瞬时转染MDA-MB-435S细胞72h,RT-PCR方法证实DBC2基因的过表达;流式细胞术检测DBC2的瞬时过表达对MDA-MB-435S细胞周期的影响,Western blot检测DBC2的过表达对细胞周期蛋白CyclinD1表达的作用。结果DBC2基因在MDA-MB-435S细胞中瞬时转染72h后,其mR-NA表达水平即可成倍增加,同时DBC2基因的过表达可诱导该乳腺癌细胞周期的G1期阻滞,并随着时间的延长出现细胞凋亡。结论DBC2基因体外抑制乳腺癌细胞生长的功能,可能通过抑制CyclinD1的表达并使细胞停滞于G1期,以及诱导细胞凋亡等机制实现。

Objective To discuss the probable mechanisms by which DBC2 inhibits proliferation of MDA-MB-435S breast cancer cell line in vitro. Methods Transient DBC2 over-expression in MDA-MB-435S cell line was generated by lipofectamine2000 transfection, and RT-PCR was performed to verify the over-expression of DBC2 mRNA. The effects of transient DBC2 over-expression was checked by flow cytometry. Western blot was used to evaluate the cell cycle related protein expression. Results The expression of DBC2 mRNA was twice more than the control group after transient transfection of pEBG-DBC2 for 72 h in MDA-MB-435S breast cancer cell line. The over-expression of DBC2 could significantly induce cell cycle G1 arrest during 48 to 72 h in vitro, and induce apoptosis after 72 h. DBC2 could also decrease the expression of Cyclin DI protein. Conclusion Transient over-expression of DBC2 in vitro could inhibit the growth of breast cancer cells, possibly through the mechanisms of decreasing the expression of Cyclin D1, inducing G1 cell cycle arrest and apoptosis.