NF-κB Mediates Effect Of Glucosylceramide Synthase On P-glycoprotein In Leukemia Drug-resistance Cell Line

Objective To investigate whether transcription factor-kappaB (NF-κB) wasinvolved in the effect of glucosylceramide synthase (GCS) on P-glycoprotein (P-gp) inK562/A02multidrug resistance cells and to explore the relationship between NF-κB andextracelluar signal-regulated kinase (ERK) in signal pathway.Methods K562/A02cells were treated with GCSsiRNA, PDTC (pyrrolidinedithiocarbamate, PDTC) and U0126, respectively.The expression of GCS and multigrugresistance protein1(MDR1) mRNA were analyzed by qRT-PCR. Various proteins ofdifferent groups were measured by Western Blotting.Results After transfected with GCSsiRNA for48h, GCSmRNA were inhibited by62%(51%-73%) and MDR1mRNA by52%(43%-61%) in K562/A02cells. Comparedwith the negative control, the relative expression of NF-κB p65in nuclear andP-ERK1/2were down-regulated, and P-gp was also inhibited significantly in72h aftertransfected with GCSsiRNA (P＜0.05). In addition,the expression of P-gp wasdecreased at24h with80μmol/L PDTC and48h with20μmol/L PDTC. BesidesP-ERK1/2being inhibited significantly when the cells were treated with20μmol/LU0126for48h, the expression of NF-κB p65in nuclear and P-gp were alsodown-regulated.Conclusion NF-κB mediates the effect of GCS on P-gp in K562/A02cells andP-ERK1/2induces activation of NF-κB in this signal transduction pathway.