PHⅡ—7增强阿霉素杀伤HL-60／ADR细胞的作用及机制研究

Mechanism of synergistic anti-tumor effect of PHⅡ-7 with doxorubicin on multi-drug resistant HL- 60/ADR cells

目的研究PHⅡ-7增强阿霉素杀伤HL-60／ADR细胞的作用及其相关机制。方法用MTT法测定阿霉素、PHⅡ-7单独及联合用药对阿霉素杀伤人急性髓系白血病耐药细胞株（HL-60／ADR）及其亲代细胞系（HL-60）作用的，IC50值，提取不同浓度PHⅡ-7处理不同时间后HL-60和HL-60／ADR细胞的RNA，RT—PCR法分析PHⅡ-7对MRP基因表达水平的影响，通过激光共聚焦显微镜和流式细胞术观察PHⅡ-7处理前后HL-60和HL-60／ADR细胞内阿霉素浓度的改变。结果PHⅡ-7本身具有抗肿瘤活性，对HL-60和HL-60／ADR的，IC50值分别为（0．83±0．08）μmol／L，（1．74±0．56）μmoL／L。PHⅡ-7还能协同提高阿霉素的细胞毒作用，HL-60组两药相互作用指数（CDI）值为0．7，HL-60／ADR组CDI值为0．43，其对耐药细胞的协同作用更为显著。随PHⅡ-7作用时间延长及剂量增加，细胞MRP基因表达水平逐渐下降，细胞内阿霉素浓度逐渐提高，可达敏感细胞的55％。结论PHⅡ-7是有效的肿瘤细胞化疗药物，还具有下调MRP耐药基因表达的作用，从而有效逆转HL-60／ADR细胞的耐药现象，协同增强化疗药物对细胞的杀伤作用。

Objective To study the synergistic mechanism between PHⅡ-7 and doxorubicin against multi-drug resistant HL-60/ADR cells and its parent HL-60 cells. Methods The anti-tumor activity of doxorubicin alone and combined with PHⅡ-7 were measured by MTT assay. RNA was extracted from the cells treated with PHⅡ-7 for different times or doses then the expression of MRP gene was measured by RT-PCR. Confocal laser scanning microscopy and FACS were used to detect the intracellular cumulation of doxorubicin in PHⅡ-7 treated HL-60 and HL-60/ADR cells. Results PHⅡ-7 has anti-tumor effect with IC50 of （0.83 ±0.08）μmol/L and （ 1.74±0.56） μmol/L for HL-60 and HL-60/ADR, respectively. It could potentiate the anti-tumor effect of dororubicin with CDI of 0.7 and 0.43 for HL-60 and HL-60/ADR, respectively.PHⅡ-7 and doxorubicin act synergistically in inhibiting the proliferation of HL-60 and HL-60/ADR cells and down-regulating the expression of MRP gene in a dose and time dependent manner. PHⅡ-7 restored the intracellular cumulation of doxorubicin in HL-60/ADR cells to 55% of that in HL-60 cells. Conclusion PHⅡ-7 can significantly hasten the cytotoxicity of doxorubicin to HL-60 and HL-60/ADR cells through down-regulating the expression of MRP. The synergistic effect was more obvious in HL-60/ADR cells.