雄黄诱导MCF-7/ADM细胞凋亡及逆转其耐药性的研究

目的探讨雄黄诱导人乳腺癌MCF-7／ADM细胞凋亡及逆转其耐药性的调节机制。方法经MTT法探讨雄黄对人乳腺癌MCF-7／ADM细胞药物敏感性的影响；用透射电镜观察凋亡细胞形态改变；应用流式细胞术，探讨凋亡抑制基因bcl-2的编码蛋白Bcl-2的改变及凋亡百分率的改变；通过荧光分光光度法观察雄黄对细胞内化疗药物阿霉素积累的影响。结果雄黄对MCF-7／ADM的耐药性有明显的逆转作用，无毒剂量（15mg，L）及低毒剂量（25mg，L）雄黄作用后，逆转倍数分别为2．3倍及2．8倍；出现凋亡细胞，凋亡百分率由0．6％分别增至2．0％（P〈0．05）及3．4％（P〈0．01）；Bcl-2表达由90．2％分别降至63．6％（P〈0．01）及52．7％（P〈0．01）；MCF-7／ADM的细胞内阿霉素浓度明显增加（P〈0．01）。结论雄黄通过降低Bcl-2表达，促进细胞凋亡，增加耐药细胞内阿霉素积累量等耐药机制的调节，部分逆转了MCF-7／ADM细胞对阿霉素的耐药性。

Studies of Realgar on Induction of Apoptosis and Reversal of Drug Resistance in Human Breast Tumor Cells MCF-7/ADM

Objective One of the major obstacle to the successful treatment of cancer in clinic is the drug-resistance phenotype.In this study,the effect of realgar(REA) on the induction of apoptosis and the reversal of drug resistance were investigated. Methods Human breast cancer line MCF-7 and its adriamycin(ADM) resistant counterpart MCF-7/ADM cells were used in this study.15mg/L REA and 25mg/L REA were selected as non-cytotoxic dose and low-cytotoxic to MCF-7/ADM cells respectively by MTT assay.Then,they were adopted to affect the growth of MCF-7/ADM cells. MTT assay was used to analyze the effect of REA on drug sensitivity to ADM.The cells apoptosis was detected by transmission electron microscope and flow cytornetry.The expressions of anti-apoptosis protein Bcl-2 were detected by flow cytometry.Finally,the intracellular accumulation of ADM in MCF-7/ADM cells was detected by fluorescent-spectrophotometry. Results REA reversed the drug-resistance of ADM in MCF-7/ADM cells with dose-dependent relationship.When 15mg/L REA or 25mg/L REA was added into the culture,the 50% inhibitory concentration(IC_(50)) of ADM in MCF-7/ADM cells was reduced from 30.4mg/L to 13.2mg/L and 10.8mg/L(P<0.01) respectively,the reversal folds were 2.3 and 2.8 respectively.The cell apoptosis was observed under transmission electron microscope and the apoptosis of MCI-7/ADM cells was increased from 0.6% to 2.0%(P<0.05) and 3.4%(P<0.01) respectively.The expression of Bcl-2 protein in MCF-7/ADM cells was reduced from 90.2% to 63.6%(P<0.01) and 52.7%(P<0.01) respectively.The intracellular accumulation of ADM in MCF-7/ADM cells was obviously increased after treatment with REA(P<0.01).Conclusion REA could obviously reduce the expression of Bcl-2,increase the intracellular ADM concentration.Finally,it induces MCF-7/ADM cell apoptosis with reversing the drug resistance to ADM partly.