Role of PTEN gene in multidrug resistance reversal in leukemia cells

Abstract

Objective To investigate the mechanism by which wild-type PTEN gene reversing multi-drug resistance(MDR) in human leukemia K562/ADM cells resistant to adriamycin(ADM).Methods The recombinant adenovirus containing green fluorescent protein and PTEN(Ad-PTEN-GFP)or empty vector(Ad-GFP) was transducted into K562/ADM cells resistant to ADM.The transduction efficiency was assessed by flow cytometry(FCM).Then the cells were treated with different concentrations of ADM,cytarabine(Ara-C) or arsenic trioxide(As2O3) 3 days after transduction.The proliferation of K562/ADM cells was examined by MTT assay,the apoptosis rate was assessed by FCM,and the IC50 of different drugs was used to calculate the drug resistance reversal fold(RF),so as to observe the effect of PTEN on reversing MDR of the 3 drugs. PTEN,NF-κB,MDR1,MDR-associated protein(MRP) and apoptosis related genes (Bcl-2,Bcl-xL,Bax) were detected by fluorescence quantitative PCR.PTEN,Akt,p-Akt and NF-κB protein levels were detected by Western blotting analysis.Results The proliferation inhibition rate and apoptosis rate of cells in Ad-PTEN-GFP plus chemotherapeutic groups were significantly higher than those Ad-GFP plus chemotherapeutic groups at 3 days after infection(MOI=200)(P0.05).PTEN transduction promoted the sensitivity of K562/ADM cells to ADM,Ara-C and As2O3,with the RF being 3.80,2.65 and 2.64 folds,respectively.K562/ADM cells in Ad-PTEN-GFP group had lower p-Akt and NF-κB(P65) protein levels and lower NF-κB,MDR1,Bcl-2 and Bcl-xL mRNA levels,and up-regulated Bax mRNA level compared with those in Ad-GFP group.Conclusion Wild-type PTEN gene may reverse drug resistance via inhibiting Akt pathway and regulating its downstream signaling molecules,such as NF-κB,MDR1,Bcl-2 and Bax.