Reversal effect of BM-cyclin 1 on multidrug resistance by down-regulating MRP2 in BALB/C nude mice bearing C-A120 cells.

Our previous study demonstrated that BM-cyclin 1, a traditional anti-mycoplasma drug, could effectively reverse the multidrug resistance (MDR) of C-A120 cells. The present study aims to explore the reversal effect of BM-cyclin 1 on MDR and its mechanisms in BALB/C nude mice bearing C-A120 cells. Immunoblotting analysis and reverse transcription-polymerase chain reaction (RT-PCR) were used to study the change in multidrug resistance-associated protein 2 (MRP2) induced by BM-cyclin 1. We found that the expression levels of MRP2 protein and mRNA in C-A120 cells treated with BM-cyclin 1 were reduced significantly. Chemical colorimetry revealed no significant change in the level of glutathione (GSH). In the xenograft model, the inhibitory rate of C-A120 cells growth in BM-cyclin 1 plus adriamycin (ADM) group was 52%, which was significantly higher than in control group (P<0.01). The immunoblotting and RT-PCR results conclusively demonstrated that BM-cycin 1 could significantly reduce the expression of MRP2 in transplanted tumor. In conclusion, BM-cyclin 1 could effectively reverse the MDR of C-A120 cells in vivo by suppressing the expression of MRP2.