米尔贝逆转耐阿霉素人乳腺癌细胞多药耐药的作用

Reversal effects of milbemycins on multidrug resistance in MCF-7/adr cells

目的探寻米尔贝类化合物尼莫克汀、米尔贝β1逆转人乳腺癌多药耐药细胞株(MCF-7/adr)多药耐药(multidrug resistance,MDR)的作用及机制。方法采用MTT比色法测定细胞生长抑制率及耐药指数;高效液相色谱(HPLC)检测细胞内阿霉素(ADR)的积累变化;荧光分光光度仪检测罗丹明123(Rh123)在肿瘤细胞内的积累;通过RT-PCR与流式细胞仪检测MDR1基因与P-糖蛋白(P-gp)表达的变化。结果 5μmol·L-1的尼莫克汀、米尔贝β1可明显增强MCF-7/adr对ADR的敏感性,增加细胞内ADR及Rh123的积累,且呈剂量依赖关系,不同程度降低MDR1和P-gp的表达。结论尼莫克汀、米尔贝β1对MCF-7/adr的耐药有一定的逆转作用,且尼莫克汀效果好于米尔贝β1。

Aim To explore the reversal of MDR（ mul- tidrug resistance ） by nemadectin and milbemycin β1 from the milbemycin family to adriamycin-resistant hu- man breast carcinoma cells （MCF-7/adr）. Methods MTI＇ assay was used to evaluate the cell suppression rates and reversal effects. Intracellular accumulation of adriamycin was determined by HPLC. The accumula- tion of rhodamine 123 （ Rh123 ） was measured with spectrofluorometer. The expressions of P-gp and the MDR1 gene encoding P-gp were tested by flow cytometry and reverse-transcriptase PCR. Results Nemadec- tin and milbemycin β1 at the high dose of 5μmol·L^-1 significantly increased the sensitivity of MCF-7/adrcells to adriamycin. They also increased the intracellu- lar accumulation of adriamycin and Rhl23 in MCF-7/ adr cells in a dose-dependent manner. Expression of both P-gp and MDR1 was down-regulated to different level. Conclusion Nemadectin and milbemycin β1 can partly reverse multidrug resistance of MCF-7/adr, and the effect of nemadectin is better than that of mil- bemycin β1.