| BACKGROUND & OBJECTIVE Tetrandrine,a bisbenzylisoquinoline albaloid isolated from the Chinese herb"Hanfangji"(Radix Stephania Tetrandra),could effectively reverse P-glycoprotein-mediated multidrug resistance. This study was to investigate the reversal effect of tetrandrine on human multidrug resistance carcinoma cell line KB-MRP1.METHODS The effects of tetrandrine on proliferation of KB-3-1 and KB-MRP1cells were observed by MTT assay. The inhibitory rate of cisplatin (DDP), vincristine (VCR), adriamycin (ADM) and etoposide (VP16) without and with different concentrations of tetrandrine to KB-3-1 and KB-MRP1 cells was evaluated by MTT assay. The influence of tetrandrine on accmulation of ADM in KB-MRP1 cells and vincristin–induced apoptosis was determined by flow cytometry (FCM).RESULTS Tetrandrine at the concentration of 1.5μg/ml and below was not significantly cytotoxic to KB cells. The resistance of KB-MRP1 cells to VCR, ADM, VP16 and DDP were 21.23, 38.39, 12.47 and 1.31 folds respectively to that of KB-3-1 cells. With 1μg/ml tetrandrine added, chemo-sensitivity of KB-MRP1 cells to VCR, ADM and VP16 increased 4.96, 5.85 and 4.24 folds respectively. The chemo-sensitivities of KB-MRP1 cells to those chemotheraputic agents were much higher when treated with 1.5μg/ml of tetrandrine. Accumulation of ADM in KB-MRP1 cells was significantly raised and the vincristin-induced apoptosis of KB-MRP1 cells was enhanced significantly when treated with tetrandrine at the concentration of 1.5μg/ml.CONCLUSIONS Tetrandrine could moderately reverse the multidrug resistance of KB-MRP1 cells by increasing accumulation of chemo-drugs in cells and promoting apoptosis. |
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