Effect of the content of glutathione for multidrug resistance-associated protein 1

Objective To investigate the apoptosis-inducing effect,inhibiting multidrug resistanceassociated protein 1 (MRP-1) and mRNA expression of arsenic trioxide (As2O3) and buthionine sulfoximine (BSO) in multidrug-resistant cell K562/ADM.To compare the effect of As2O3 and the combined group.To determine the effect of intracellular glutathione (GSH) content on the arsenic effect.Methods The arsenic group (0.5 μmol/L,2.0 μmol/L,5.0 μmol/L) solo or combined BSO (100 μmol/L) applied in multidrugresistant cell K562/ADM.The cell proliferating activity was assessed with MTT assay.The cell apoptosis effect was detected by Annexin-V and propidium iodide (PI) staining.Intracellular GSH contents were measured using GSH Assay Kit by spectrophotometry.MRP1 expression was determined by flow cytometry.MRP1 mRNA expression were directed by semi-quantitative RT-PCR.Results With the GSH contents were degraded by the combination of clinic dose arsenic group (0.5 μmol/L,2 μmol/L) and BSO (100 μmol/L),the K562/ADM cell proliferating activity was obviously inhibited and the cell apoptosis-inducing effect was increased in 24 hours.In 72 hours,the rate of apoptosis with arsenic (0.5 μmol/L,2 μmol/L) were (8.32± 2.11) ％,(16.75±3.56) ％.After the GSH contents were degraded,the rates of apoptosis in the combination group (clinic dose arsenic group) were (82.15±9.28) ％ and (92.72±9.41) ％.The fluorescence intensity of MRP1 in 72 hours of the combination group (clinic dose arsenic group) was 8.20±0.92 and 10.40±2.33.The MRP1 attenuated effect of the combination group (clinic dose arsenic group) was obviously stronger than that of the high dose arsenic group (21.30±3.09).Conclusions The intracellular GSH contents closely correlate with the arsenic effect.The cell apoptosis-inducing effect of the combination of clinic dose arsenic and BSO on K562/ADM cell is obvious increased.The combination of clinic dose arsenic and BSO obviously inhibit MRP1 expression and MRP1 mRNA expression in K562/ADM cell. Key words: Neoplasms;  Multidrug resistance;  Arsenic trioxide;  Glutathione