吗丙嗪逆转多药抗药性作用及其分子机制的探讨

目的：探讨吗丙嗪逆转肿瘤多药抗药性（ＭＤＲ）的作用及其机制。方法：以ＭＴＴ与Ｆｕｒａ－２－ＡＭ法进行吗丙嗪逆转ＭＤＲ活性测定；以ＤＰＨ荧光测定法探讨吗丙嗪对膜脂流动性的影响；以荧光分光光度计法测定吗丙嗪与高钙或低钙对细胞内阿霉素（Ｄｏｘ）积累的影响及Ｆｕｒａ－２－ＡＭ法测定吗丙嗪对细胞内游离钙离子浓度的影响。结果：在浓度２．５μｍｏｌ·Ｌ－１时，吗丙嗪能显著增加ＭＣＦ－７／ＡＤＲ细胞内Ｆｕｒａ－２的积累和降低ＭＣＦ－７／ＡＤＲ对Ｄｏｘ的ＩＣ５０而对敏感株ＭＣＦ－７无明显影响，表明吗丙嗪具有逆转ＭＤＲ的作用。吗丙嗪能显著增加ＭＤＲ细胞内Ｄｏｘ积累和降低ＭＤＲ细胞的膜脂流动性。高钙或低钙对ＭＤＲ细胞内Ｄｏｘ积累无影响，吗丙嗪也不能改变１９９７－０４－１１收稿１中山医科大学中心实验室，广州５１００８９作者简介：符立梧，男，３２岁，博士，讲师，主要从事逆转多药抗药性的研究；潘启超，男，６７岁，教授，博士生导师，主要从事肿瘤药理与化疗方面的研究ＭＤＲ细胞内游离钙离子浓度。结论：吗丙嗪有逆转ＭＤＲ作用。其逆转机制与降低膜脂流动性增加细胞内ＤＯＸ积累有关，与钙离子浓度无关

The study of multidrug resistance reversal by probimane and its mechanisms

AIM: To study on the reversal of tumor multidrug resistance (MDR) by probimane and its mechanisms. METHODS: The cellular accumulation of Fura 2 and fold reversal were studied with Fura 2 AM and MTT assay, respectively. Cellular accumulation of doxorubicin(Dox) and cellular membrane fluidity were measured by fluorescence spectrophotometry. RESULTS: 10 μmol·L -1 of probimane could increase the accumulation of Fura 2 and decrease the IC 50 of the cells to doxorubicin in MCF 7/ADR and MCF 7 cells respectively. Probimane only increased the accumulation of Fura 2 and decreased the IC 50 to doxorubicin in MCF 7/ADR cells, while no effect for MCF 7 cells when the incubation concentration of probimane was decreased. This suggested probimane could partially reverse MDR. The increase of cellular Dox accumulation and the decrease of membrane fluidity were caused in the presence of probimane in MCF 7/ADR. Probimane could not change cellular free calcium ion concentration in both MDR and sensitive cells. And Dox accumulation was changed neither by high extracellular Ca 2+ (by addition of CaCl 2) nor by the decrease of Ca 2+ (by addition of EGTA). CONCLUSIONS: Probimane can reverse MDR in MCF 7/ADR cells, and its reversal mechanism was related with the decrease of membrane fluidity but not related to extracellular calcium concentration.