The reversal of P-glycoprotein-mediated MDR by GP associated with chemotherapeutic drugs

Aim To investigate the reversal effect of GP on the activity of P-gp in MDR-associated tumor cells and to develop a useful approach to inhibit the drug efflux in MDR-associated tumor cells.Methods MTT assay was used to detect the effect of GP on the cytotoxicity of cisplatin(DDP),vincristine(VCR) and doxorubicin(DOX).Flow cytometry was used to determine the influence of GP on the intracellular accumulation of DOX.Results GP synergistically increased the cytotoxity and the intracellular accumulation of DOX in K562/DOX cells;GP also increased the cytotoxity of DDP,DOX,and VCR in A549/DOX cells.However,the effect was relatively weak.Conclusion GP could increased the cytotoxity and the intracellular accumulation of chemotherapeutic drugs in MDR-associated tumor cells.GP may be a promising MDR modulator.