Study on the Administration Method of Combining Tetrandrine with Adriamycin to Reverse Drug-Resistance of Leukemia

Increasing drug efflux pumps (P-gp) on the cell membrane due to the overexpression of MDR1 gene in tumor cells is the main mechanism of multidrug resistance of cancer cells. P-gp belongs to the ATP-binding cassette family and functions as a transmembrane efflux pump that translocates chemotherapy drugs from an intracellular to an extracellular domain; thus, it is impossible to achieve efficient drug accumulation in tumor cells. Tetrandrine (TTD) has been shown in both in vitro and in animal experiments to reverse MDR by reducing the expression of MDR1 mRNA and P-gp. However, the effect of administration of TTD one week before chemotherapy is not ideal in the current clinical trials. In view of the previous in vitro and animal experiments have confirmed the effect of TTD in reversing the drug resistance of leukemia, this study returned to the cell experiment, selected K562 and K562/ADM cell lines as the research object, through different ADM combined with TTD administration sequences, to detect the inhibitory effect of different administration sequences on cell proliferation and whether it affected the intracellular ADM concentration, P- gp ATPase activity, MDR1 mRNA and P-gp expression levels, comparing the effect of TTD combined with ADM different administration sequences on the reversal of MDR in K562/ADM cells. We found that TTD can significantly antagonize P-gp-mediated ADM resistance by competitively binding P-gp and down-regulating P-gp expression and we, therefore, conclude that the co-administration of TTD, as a drug resistance reversal agent with ADM may be a better administration in the clinic.