多柔比星诱导乳腺癌细胞PARP-1活性上调依赖于Kif4A蛋白低表达

背景与目的：化疗作为乳腺癌术后治疗的重要手段，由其引发的耐药现象备受关注，而耐药的出现与DNA损伤修复异常增强密切相关。驱动蛋白家族成员4A(kinesin family member 4A，Kif4A)和聚腺苷酸二磷酸核糖聚合酶-1[poly(ADP-ribose)polymerase，PARP-1]是重要的DNA损伤修复分子。本研究探讨Kif4A在多柔比星诱导乳腺癌细胞PARP-1活性上调中的作用及意义。方法：蛋白质印迹法检测多柔比星处理后乳腺癌MDA-MB-231和MCF-7细胞Kif4A蛋白表达及PARP-1活性的变化；并检测高表达Kif4A蛋白后，乳腺癌细胞PARP-1蛋白表达及其活性变化；流式细胞技术检测多柔比星联合PARP-1抑制剂3-氨基苯酰胺(3-Aminobenzamide，3-ABA)干预后乳腺癌细胞的凋亡情况。结果：多柔比星能上调PARP-1活性并诱导乳腺癌细胞Kif4A蛋白低表达，两者都呈浓度和时间依赖性；高表达Kif4A后，PARP-1活性被明显抑制，细胞凋亡数增加，而多柔比星能部分逆转由Kif4A高表达而引起的PARP-1活性抑制。多柔比星和3-ABA都诱导乳腺癌细胞凋亡，联合使用能增加细胞凋亡，与单独使用比较，差异有统计学意义(P<0.05)。结果还显示，多柔比星、PARP-1抑制剂3-ABA及高表达的Kif4A诱导的MDA-MB-231细胞凋亡数高于MCF-7细胞，差异有统计学意义(P<0.05)。结论：多柔比星诱导乳腺癌细胞PARP-1活性上调依赖于细胞Kif4A蛋白低表达，Kif4A有望成为逆转多柔比星耐药的新靶点。

Epirubicin up-regulates PARP-1 activity dependent on Kif4A low expression in breast cancer cells

Background and purpose: Chemotherapy is the important way of breast cancer treatment, but the drug-resistance has attracted special attention. The emergence of drug resistance is closely related to the abnormal enhancement of DNA-damage repair. Both Kif4A and PARP-1 are important molecules of DNA repair. The research investigated the function of Kif4A in epirubicin up-regulating the activity of PARP-1 in breast cancer cells and possible significance. Methods: Western blot was used to detect the expression of Kif4A and PARP-1 after treatment with epirubicin in MDA-MB-231 and MCF-7 cells; the expression of PARP-1 and its activity were detected after high expression of Kif4A and treatment with epirubicin; FCM was used to detect cell apoptosis after treatment with epirubicin combined with PARP-1 inhibitor 3-ABA. Results: Epirubicin up-regulated PARP-1 activity and induced low expression of Kif4A in breast cancer cells, both of them showed dose-dependent and time-dependent. After high expression of Kif4A, the activity of PARP-1 was inhibited and the apoptosis of cells increased, epirubicin partially reversed the activity of PARP-1 inhibited by high Kif4A expression. Both of epirubicin and 3-ABA induced cell apoptosis, combination of them further increased cell apoptosis compared with alone used (P<0.05). The results also showed the apoptosis rate of MDA-MB-231 cells induced by epirubicin, PARP-1 inhibitor 3-ABA and high expression Kif4A was higher than that of MCF-7 cells (P<0.05). Conclusion: Epirubicin increases the activity of PARP-1 dependent on the low expression of Kif4A in breast cancer cells. Kif4A might become a novel target for overcoming resistance of epirubicin.