Reversion Of Multidrug Resistance By Nitidine Chloride On Multidrug Resistant Tumor Cells

Objective:To investigate the reversal effect of Nitidine Chloride on human multidrug resistant tumor cells, developing low toxicity, effective reversal agents.Methods:Cultured tumor cells Hepg2, A2780, A549, Hela, CNE-1, KB and their corresponding multidrug resistant cells in CO2 incubator with cell culture bottles, demonstrated the cell sensitivity of chemotherapeutic drugs(ADM, VCR, VP-16, HCPT) by MTT, detected MDR1 expression by RT-PCR, analyzed P-gp expression by Flow Cytometry when the cells grow to exponential phase for conforming the multidrug resistance of the multidrug resistant tumor cells.Different concentration of Nitidine Chloride acted on multidrug resistant cells Hepg2/ADM, A2780/ADM, A549/ADM, Hela/ADM, CEN-1/ADM, KB/ADM for 48h, Screened three concentration on cell inhibition rate of less than ten percent by MTT for the reversal experiment.The six multidrug resistant tumor cells were cultured conventionally to 1× 106, randomly divided each multidrug resistant tumor cell into four groups: positive control group(5μmol·L-1VRP), low dose group of low toxicity NC(0.375mg·L-1/NC), middle dose group of low toxicity NC(0.75mg·L-1NC), high dose group of low toxicity NC(1.5mg·L-1NC),3 parallel samples each. These groups were respectively added to 5μumol·L-1VRP,0.375mg·L-1NC, 0.75mg·L-1NC, 1.5mg·L-1NC for 48h. The cell sensitivity to chemotherapeutic drugs was demonstrated by MTT. MDR1 expression was detected by RT-PCR. P-gp expression was analyzed by Flow Cytometry.Results:Compared with tumor cells Hepg2, A2780, A549, Hela, CNE-1, Kb, the IC50 value to ADM, VCR, VP-16, HCPT, the MDR1 expression and P-gp expression of their corresponding multidrug resistant cells were up-regulated significantly(P<0.01 or P<0.05).The cell inhibition rate is less than ten percent at 1.5mg·L-1 concentration or below 1.5mg·L-1concentration, thus, screening 0.375,0.75,1.5mg·L-1 NC for the reversal experiment.Compared with the six multidrug resistant cell groups, the IC50 value to ADM, VCR, VP-16, HCPT, the MDR1 expression and P-gp expression of positive control group,0.375 mg·L-1NC group, 0.75mg·L-1NC group and1.5 mg·L-1NC group of each multidrug resistant cells were down-regulated(P<0.01 or P<0.05).Conclusion:Low toxicity concentration of NC can decrease the MDR1 expression and P-gp expression, reverse the multidrug resistance of multidrug resistant tumor cells.