Grape seed proanthocyanidins induce apoptosis and autophagic cell death in human hepatoma HepG2 cells

Aim:To investigate the inhibiory effect of procyanidins on human hepatoma HepG2 cell lines and the possible mechanism.Methods: Improved MTT assay(WST-8 method) and cell colony formation inhibitory assay were used to investigate the inhibition effect of procyanidins on human hepatoma HepG2 cell lines.Changes in cell cycle,DNA ploidy and apoptotic cell percentage were calculated by flow cytometry.Laser confocal microscopy and Western blotting assay were used to determine cell autophagy.Results: The results of WST-8 method shows that procyanidins with different concentrations inhibited human hepatoma HepG2 cells in a dose-dependent manner.The IC50 for procyanidins against human hepatoma HepG2 cells for 48 hours was 1.304×10-1g/L.Cell colone formation inhibition assay demonstrated that cell clones were decreased with increase of the concentration of procyanidins.PI staining analysis showed that cell cycle was arrested in G1 phase.DNA ploidy analysis showed that the percentage of hypodiploid cells was accumulated in a dose-dependent manner.Annexin V-FITC/PI staining analysis also showed a dose-dependent effect on late apoptotic and necrotic cells.By using laser scanning confocal microscopy it was observed that LC3 aggregates significantly,the green fluorescence of control group was dispersed.Western-blotting assay showed that the LC3-II protein expression levels increased gradually with increasing of procyanidins.Conclusion:Procyanidins inhibits the cell survival of human hepatoma HepG2 cells in a dose-dependent manner and arrestes cells at G1 phase.Procyanidins inhibits cell growth by inducing apoptotic and autophagic death.