Objective: To investigate the effect of chloroquine in reversing multidrug resistance (MDR) of HNE1/DDP cell line and explore the mechanism.
Methods: MTT assay was used to detect the cell viability of HNE1 and HNE1/DDP after exposure to different concentrations of DDP (2, 4, 8, 16 and 32 µmol/L) and different concentrations of chloroquine (5, 10, 20, 40, and 80 µmol/L). q-PCR was used to assess the expression of MDR1 mRNA and Western blotting was employed to detect P-glycoprotein (P-gp) expression in HNE1 and HNE1/DDP cells exposed to 5 and 10 µmol/L chloroquine. The cell apoptosis rate of HNE1 and HNE1/DDP cells exposed to 10 and 20 µmol<L chloroquine was determined by PI assay.
Results: Chloroquine exposure caused dose-dependent suppression of the proliferation in both HNE1 and HNE1<DDP cells, and significantly reversed multidrug resistance in HNE1<DDP cells. The expressions of MDR1 mRNA and P-gp protein were significantly lowered in the cells treated with chloroquine.
Conclusion: Chloroquine can reverse multidrug resistance in HNE1<DDP cells possibly through down-regulation of MDR1 and inhibition of P-gp protein.