[Effect of regulation of Y-box protein 1 by RNA interference on the doxorubicin induced mdr1 gene expression in K562 cells].

OBJECTIVE: To investigate the effect of YB-1 on the transcription of induced mdr1 gene expression in K562 cells. METHODS: K562 cells were treated with doxorubicin (DOX) at different concentrations and times. Expression of mdr1 and YB-1 genes was examined by RT-PCR and P-glycoprotein (P-gp) by flow cytometry. Cyto/nuclear protein was extracted for YB-1 detection by Western blotting. The expression of YB-1 gene in K562 cells was inhibited by YB-1 gene specific RNA interference (RNAi), then the expression of mdr1 and P-gp in YB-1 gene silenced cells treated with DOX was detected. RESULTS: The mdr1 gene as well as its corresponding protein P-gp was highly expressed in DOX exposed K562 cells. DOX up-regulated the expression of YB-1 gene, and promoted YB-1 protein nuclear translocation. On YB-1 gene silenced, the expressions of mdr1 gene and P-gp were obviously down-regulated in DOX treated K562 cells. CONCLUSION: Doxorubicin can induce the expression of mdr1 gene in K562 cells, which may result from the transcription of mdr1 gene by activated YB-1.