Effect Of Glucosylceramide Synthase Via ERK Signal Transduction Pathway On P-gp Expression In Leukemia Multidrug Resistance Cell Line

Objective To investigate whether the effect of glucosylceramide synthase (GCS)on P-glycoprotein (P-gp) expression via extracellular signal-regulatred kinase(ERK)pathways in leukemia K562/A02cell line.Methods K562/A02multidrug resistance cells were treated with GCSsiRNA andU0126, respectively. The expressions of MDR1mRNA were analyzed by qRT-PCR.Meanwhile, phosphorylated extracellular signal-regulatred kinase1/2(P-ERK1/2), totalERK1/2protein and P-gp in different groups were measured by western blot.Results After treated with U0126, the level of P-ERK1/2was decreased alongwith the higher concentration of the U0126. P-ERK1/2and P-gp were obviouslydown-regulated at the concentration of20μmol/L、40μmol/L and60μmol/L U0126. TheGCSmRNA was inhibited by70.50%(58.00%~76.00%) in K562/A02cells after beingtransfected with GCSsiRNA. Compared with the negative control RNAi, K562/A02cells exibitted significantly down-regulated level of P-ERK1/2(P<0.01) at48hoursafter transfected with GCSsiRNA whereas there was no obviously influenced in theexpression of P-glycoprotein. At72hours post-transfection with GCSsiRNA, theexpression of P-glycoprotein in K562/A02cells was down-regulated signfficantly（P<0.05）.Conclusion GCS may affect the expression of P-gp by ERK signal transductionpathway in leukemia cells.