β-Sitosterol enhances the anti-tumor efficacy of sorafenib in hepatocellular carcinoma via the FXR/LXR/ SREBP1/ FASN pathway.

OBJECTIVE: To investigate whether β-Sitosterol (SIT) enhanced the anticarcinogenic effects of sorafenib on HCC. METHODS: The anti-tumor effects in vitro were detected using a Cell Counting Kit-8 assay, 5-ethynyl-29-deoxyuridine assay, flow cytometry, wound healing assay and tube formation assay. Blood samples were collected for in vivo biochemical and metabolomic analyses. Anticarcinogenic activity was evaluated by Masson's trichrome staining in conjunction with hematoxylin and eosin staining. Bioinformatics analyses were conducted to investigate the potential associations between lipid metabolism and HCC. Finally, the lipid- related protein expression was detected by immunohistochemical staining (IHC) and western blot (WB) analysis. RESULTS: In vitro studies demonstrated that the combination of SIT and sorafenib promoted apoptosis and inhibited the growth, proliferation, migration and vasculogenic mimicry formation and of HCC cells. Additionally, the anti-hepatocarcinoma activity of the combination treatment was better than that of sorafenib treatment alone to inhibit diethylnitrosamine-induced HCC progression. Metabolomic, bioinformatics, IHC and WB analyses suggest that SIT regulates lipid metabolism by modulating the expression of FXR, LXR, SREBP1, and FASN. CONCLUSIONS: The data suggest that SIT enhances the effect of sorafenib by regulating lipid metabolism targeting FXR, LXR, SREBP1, and FASN, indicating that the strategies to union potent drugs regulating lipid metabolism with sorafenib deserves to be further explored.