Differentiation Induced And Colony Formation Breakdown In HepG2 Cells Treated With ATRA And The Mechanism Of Action

Objective To study the differentiation,apoptosis,the ability of colony formation and the expression of osteopontin(OPN) of human hepatoma HepG2 cells in vitro and its mechanism induced by all-trans-retinoic acid(ATRA). Methods HepG2 was treated with 1 or 10μmol/L ATRA.The morphology of HepG2 was observed by light microscope and the diversity ofγ-glutamyl transpeptidase(γ-GT) and alpha-fetoprotein(AFP) were detected by kinetics analysis.The cell proliferation of HepG2 was analyzed by MTT assay and the ability of colony formation was assay by soft agar.The cell apoptosis was measured with Hoechst dyeing.The phosphorylation of ERK2 and the expression of OPN and NF-κB were studied by western blot. Results The proliferation of HepG2 significantly inhibited,the differentiation and apoptosis was induced by ATRA,moreover the specific activities ofγ-GT and the secretary amount of AFP significantly decreased.The HepG2 cells could grow to clone on soft agar,but the size and quantity distinguished diminish after stimulated by ATRA.The western blot indicated the phosphorylation of ERK2 and the expression of OPN down-regulation significantly in HepG2 cells treated with ATRA for 5d.When the HepG2 cells was treated with 10μmol/L ATRA for 70d,the phosphorylation of ERK2 and the expression of OPN was not found,while no change of ERK2 and NF-κB. Conclusion ATRA was effective to induce differentiation of HepG2 cells . ATRA could induce differentiation,inhibit proliferation and broke down the ability of colony formation by inhibiting the phosphorylation of ERK2 and the expression of OPN.