Objective: To analyze the methylation patterns of mdr1 gene promotor in both K562 cell and K562/DNR cells and the relationship between promotor methylation and P-gp expression.
Methods: mdr1 gene expression was analyzed by flow cytometry and RT-PCR, methylation status of the promotor of mdr1 gene by bisulfite-sequencing (including two GC-box).
Results: mdr1 gene was found methylated at GC-box and not expressed in K562 cells, but unmethylated and expressed respectively in K562/DNR cells.
Conclusion: The methylation patterns of mdr1 gene promotor in K562/DNR and K562 cells were different. mdr1 gene silencing was associated with the promotor methylation.