TGF-β rescues HepG2 cell from cytotoxic effects of anticancer drugs by increasing drug efflux potential. (a) qRT-PCR analysis of drug efflux transporters ABCB1, ABCC2, ABCC1 and ABCG2 in HepG2 cells treated with TGF-β in the presence or absence of PXR agonist SR12813 and TGF-β inhibitor LY2157299. (b and c) Representative images (b) and Analysis (c) of rhodamine 123, CFDA and mitoxantrone efflux potential of HepG2 cells. Asterisks represent significant differences (*p < 0.05, **p < 0.005, ***p < 0.0005). Data are mean ± SD or representative of three independent experiments performed in triplicate.