EGFR inhibition by siRNA reduces the ABC-transport protein mRNA expression and cellular proliferation of HepG2 cells. A: HepG2 cells were transfected with EGFR siRNA. EGFR mRNA expression was assessed by RT-PCR. Columns average of three independent experiments, bars SD. EGFR protein expression analysed by Western blot. B: ABC-transport protein mRNA expression was determined by RT PCR in HepG2 cells treated with EGFR siRNA. Columns average of three independent experiments, bars SD. *p ≤ 0.05; **p ≤ 0.001 compared to the untreated control group. C: HepG2 cells were treated with EGFR siRNA, Gemcitabine 11, 4 μg/ml, Gemcitabine 11, 4 μg/ml plus EGFR siRNA, Gemcitabine 114 μg/ml and Gemcitabine 114 μg/ml plus EGFR siRNA. Cellular viability was analyzed by MTT assay. A minimum of three independent experiments was performed.