葫芦素B逆转人乳腺癌细胞MCF-7/Dox多柔比星耐药的作用及机制研究

Effects and Mechanisms of Cucurbitacin B on Reversal of the Chemoresistance to Human MCF-7/Dox Breast Cancer Cells

目的:探讨天然化合物葫芦素B(Cucurbitacin B,CuB)对多柔比星(Doxorubicin,Dox)耐药的人乳腺癌细胞MCF-7/Dox的耐药逆转作用及机制。方法:台盼蓝计数实验及集落形成率实验检测CuB对细胞生长的抑制作用;MTT法检测CuB对MCF-7/Dox的抑制作用及逆转Dox耐受作用;核染色免疫荧光及免疫印迹法分析CuB诱导细胞凋亡作用及逆转MCF-7/Dox细胞Dox耐药的作用机理。结果:CuB可以显著抑制MCF-7/Dox细胞增殖、生长,诱导凋亡及逆转Dox耐药。机制研究发现,CuB能够抑制与肿瘤多药耐药相关蛋白的表达,包括P-糖蛋白(P-glycoprotein,P-gp)、多药耐药性相关蛋白(multidrug resistance-associated protein 1,MRP1)和细胞周期蛋白Cyclin D1。CuB可以诱导Caspase依赖性的细胞凋亡和降低Akt的磷酸化。CuB通过诱导蛋白磷酸酶2A(protein phosphatase 2A,PP2A)的活化实现对Akt活性的抑制,而下调蛋白磷酸酶2A癌性抑制因子(Cancerous inhibitor of protein phosphatase 2A,CIP2A)可以活化PP2A。结论:CuB能够逆转MCF-7/Dox对Dox的耐药并诱导其凋亡,其机制可能是抑制了CIP2A/PP2A/Akt信号级联。

Objective To explore the effects and mechanisms of natural compound（Cucurbitacin B,CuB） on reversing drug resistance to doxorubicin（Dox）-resisted human breast cancer（MCF-7/Dox） cells. Methods Trypan blue dye staining,MTT and colony formation assay were used to detect the inhibitory effects of CuB on the growth of MCF-7/Dox cells. DAPI staining and Western blot were used to investigate the mechanisms of CuB on reversing Doxorubicin-resisted MCF-7/Dox cells. Results CuB inhibited MCF-7/Dox cell proliferation,cell viability,and reversed chemoresistance to doxorubicin.CuB down-regulated the expression of P-glycoprotein,multidrug resistance-associated protein 1,and Cyclin D1. CuB also induced caspase-dependent apoptosis,and decreased phosphorylation of Akt（p Akt）. The suppression of p Akt was mediated by CuB-induced activation of protein phosphatase 2A（PP2A） through the suppressing CIP2 A. Conclusion The CIP2 A/PP2 A/Akt pathway may mediate the reversal effect of CuB on Doxorubicin-resisted MCF-7/Dox cells.