Two kinds of sterols extracted from Leucocalocybe mongolica induced HepG2 cell apoptosis and their antitumor effect in H22 tumor-bearing mice and their possible mechanism

Sterols are one of the main components of medicinal fungi with antitumor effect. In this study, Ergosta-4, 6, 8(14), 22-tetraen-3-one (ET) and (22E, 24R)-ergosta-7, 22-dien-3β, 5α, 6β-triol (ED) were obtained from Leucocalocybe mongolica, which are the first time to study the induction of HepG2 cell apoptosis and the anti-tumor effect and related mechanism of H22 tumor-bearing mice METHOD: The chemical structures were defined by IR and NMR. In vitro, the cytotoxicity assay used was the CCK8 assay. Flow cytometry was used for HepG-2 cells apoptosis analysis which examined via Annexin V-FITC/PI double staining. And the related expression levels of apoptosis-associated proteins were determined by western blot analysis. In vivo, ICR male mice were randomly assigned six groups: Model, CTX were 25mg/kg/d, two concentrations of ET and ED were 0.025, 0.05, 0.1mmol/kg/d. Relevant biochemical indicators were detected by Elisa assay, H&E staining, TNUEL assay, immunohistochemistry and western blot RESULTS: In vitro, ET and ED showed a significant cytotoxic effects against HepG2, MCF‑7, and HeLa cells, especially HepG-2 cells, and both ED and ET have a good effect on inhibiting the proliferation of Hepg-2 cells. In vivo, The ET and ED significantly decreased the tumor volume and VEGF levels, but serum cytokine levels of IFN-γ, IL-2, IL-6 and TNF-α. H & E staining, TUNEL assay, immunohistochemistry, and western blotting indicated that the both ET and ED exhibited antitumor activity in vivo by promoting apoptosis and inhibiting angiogenesis. Conclusion: These results indicated that both ET and ED have a wonderful inhibitory effect on the proliferation of HepG-2 cells in vitro and anti-H22 tumor in vivo.

Keywords: 22-dien-3β; 22-tetraen-3-one (ET) (22E 24R)-ergosta-7; 5α; 6β-triol (ED); Ergosta-4 6 8(14); HepG2 cells; apoptosis; biochemical indicators; cytotoxicity.