Reversing mechanism of multidrug resistance of human bladder carcinoma drug-resistant cell line BIU-87/ADM by tetrandrine

Abstract

Objective To Investigate the reversal effect and the mechanism of tetrandrine (TET) on human bladder carcinoma cell line BIU-87/ADM. Methods The effects of TET ( 1.0, 1.5, 2. 0, 2. 5mg/L) on the growth of BIU-87 and BIU-87/ADM cells were measured by CCK assay. The potential of 1 mg/L TET to reverse multidrug resisitance (MDR) was also determined by CCK assay. The apoptosis of cell lines induced by 1 mg/L TET was evaluated by Annexin-V and PI followed by flow cytometry (FCM).The effects of 1 mg/L TET on the expression of P-gp and MDR1 were separately measured by immunofluorescence and reverse transcription-polymerase chain reaction (RT-PCR), and the expression of Caspase-3 and Survivin was analyzed by immunocytochemical technique and RT-PCR. Results TET at the concentration of 1.0 mg/L which had no obvious cytotoxicity to the BIU-87 and BIU-87/ADM cells increased the cytotoxicity of adriamycin (ADM) in BIU-87/ADM cells greatly, with a reversal fold of 5. 33, but had no significant effect on BIU-87 cells, with a reversal fold of 1.33. The ADM-induced apoptosis rate in BIU-87 and BIU-87/ADM cells was (57. 79 ± 4. 73 ) ％ and ( 12.42 ± 3.24 ) ％ respectively. After treatment of BIU-87/ADM cells with 1.0 mg/L TET, the apoptosis rate was increased to (40. 86 ±4. 35)％, but it made no difference in BIU-87 cells. The expression of mdr1 and P-gp was suppressed by TET in BIU-87/ADM cells. Compared to the ADM group, Caspase-3 was more highly expressed in BIU-87/ADM cells of ADM +TET group. However, Survivin had the opposite result. Conclusion TET can reverse the MDR of the human bladder carcinoma BIU-87/ADM cell line, which may be associated with the decreased expression of P-gp and increased apoptosis. Key words: Tetrandrine; Adriamycin; Bladder carcinoma; Drug resisitance