Western blot analysis
Lysates of HepG2 cells (which were treated with 5-Aza-2-DC and tacrolimus) were run on 8% sodium dodecyl sulphate-polyacrylamide gels, transferred to polyvinylidene difluoride membranes, and incubated with P glycoprotein (Abcam Inc. Cambridge, MA). Antibody binding was detected using enhanced chemiluminescence ECL Plus western blotting detection reagents (Merck Millipore Ltd. Tullagreen, Carrigtwohill, Co. Cork, IRELAND).