The expression of ABCG2 in hepatic cell lines. A. The basal ABCG2 mRNA and protein expression in human hepatic cell lines IHH, HuH-7, HepG2 and JHH-6. The data represented the mean ± SD of minimum three independent experiments. Statistical student’s t test: mRNA **p<0.01 to IHH, protein ##p<0.01 to IHH. B. The folds of ABCG2 mRNA up-regulation after exposure to 5 μM Dox for 24 hours compared to basal expression considered (1.00). Statistical students’ t test: ** p<0.01 to basal expression of each cell lines. The mRNA expression was normalized to reference genes 18S-rRNA and β-actin. Protein blot showing a representative Western Blot of ABCG2 (72 kDa) and ABCB1 (170 kDa) protein. Symbol: – control (basal level), + Dox.