Effect of hypoxia inducible factor1-α inhibitor on reversal of multidrug resistance of K562/A02 cell line

Objective To study the reversal effect of the hypoxia inducible factor( HIF)-1α inhibitor,YC-1 ,on muitidrug resistance of K562/A02 cells and its mechanism. Methods Pre- and post- incubation with adriamycin (ADM) alone or in combination with YC-1 for 48 h, the proliferation capacity of K562/A02 and K562 cells were evaluated by MTT assay. The apoptosis rate of K562/A02 cells after treated with 0,5,10 and 20 μmol/L YC-1 alone or in combination with 1 mg/L ADM and intracellular ADM concentration were analyzed by flow cytometry(FCM). The mRNA levels of HIF-1α and mdr1 genes were determined by semi-quantitative RT-PCR. The protein levels of HIF-1α and P-glycoprotein (P-gp) were detected by Western blot. Results The IC50 of ADM for K562 and K562/A02 cells were ( 1.56 ± 0.07 ) mg/L and (42.98 ±3.15) mg/L respectively. The resistance of K562/A02 cells to ADM was 27.55- fold higher of that of K562cells. After treatment with YC-1 (5μmol/L, 10μmol/L, 20 μmol/L) for 48h, the resistances of K562/A02cells to ADM were 24.63-, 16.38- and 10.71- fold increase respectively. After treatment of K562/A02 cell with YC-1(0 μmol/L, 5 μmol/L, 10 μmol/L, 20 μmoL/L) alone or in combination with 1 mg/L ADM for 48 h, the apoptotic rates were ( 1.9 ± 0. 9) %, (4.9 ± 0. 9 ) %, ( 5.8 ± 1.1 ) %, and ( 9.3 ± 1.4 ) % and(2.3 ± 0.7 ) %, (8.2 ± 1.2) %, ( 19.0 ± 1.7 ) %, and ( 34.5 ± 2.4 ) % respectively. The intracellular flucorescence intensity of ADM were 232 ±33, 1300 ±219, 1961 ±240 and 3342 ±269 in the combined treatment group. With the increase in YC-1 concentration, the levels of mdr1 mRNA reduced, while that ofHIF-1α mRNA had no obvious change.Furthermore.the expressions of HIF-1α and P-gp were also decreased in K562/A02 cells.Conclusion YC-1,as a HIF-1 inhibitor,cau reverse multidrug resistance of K562/A02cells through down-regulating HIF-1α and p-gp.