Autophagic Cell Death of Human Hepatoma Cells Induced by Endostar, a Recombinant Human Endostatin

Aim: The aim of this study was to explore the contribution of different doses of Endostar (endostotin, YH-16) on autophagic death in human hepatocellular carcinoma cells. Methods: Exponentially growing HepG2 cells were treated by different doses of Endostar. Cell viability was measured by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The existence of autophagosomes in hepatocellular carcinoma cells was observed using transmission electron microscopy (TEM) and the quantities of autophagosomes were assessed using a confocal laser microscopy. Further, the expression level of microtubule-associated protein light chain 3-II(LC3-II) was tested and quantitated by Western blotting. Results: Autophagosomes of HepG2 induced by Endostar were observed at 24 hours after treatment, and the amount of autophagosomes increased along with concentration. Meanwhile, Western blotting showed LC3-II protein, indicating the occurrence of autophagy, was expressed to correlate with the dose of Endostar. Meanwhile, the result of the MTT assay showed that the proliferation of cells was inhibited by Endostar in a dose-dependent manner; when the concentration was as high as 400 mu g/mL, the inhibition of cells proliferation was 55.0%. Conclusions: Taken as a whole, the results demonstrate that Endostar suppressed proliferation and triggered cell death in HepG2 cells by autophagy induction that was dose-dependent. These findings provide mechanistic insight into Endostar action.