The homology of epidermal growth factor receptor pathway substrate 8 (EPS8), EPS8L3, is elevated significantly in hepatocellular carcinoma (HCC) tissues and cell lines compared with the normal liver tissues and cell lines. The MTT and colony formation assays demonstrated that overexpressing EPS8L3 enhances, while silencing reduces the proliferation of HCC cells. Further experiments illustrated that overexpressing EPS8L3 promotes the expression of p-AKT, Cyclin D1, but inhibits the transcriptional activity of FOXO1. Besides, colony formation assay demonstrated that AKT inhibitor suppresses the effect of EPS8L3 on proliferation in EPS8L3-overexpressing cells, whereas AKT restores the proliferation of EPS8L3-silenced cells, suggesting that EPS8L3 might promote proliferation by hyperactivating the AKT signaling pathway and subsequently inhibiting the FOXO1 transcriptional activity. Our results provide new view between EPS8L3 and progression of human HCC, suggesting that EPS8L3 may be a novel therapeutic target for HCC.

ABSTRACT. Our study aimed to investigate the co-localization and protein-protein interactions between ezrin and p65 in human breast cancer cells. Liquid chromatography-mass spectrometry (LCMS) was used to uncover novel protein interactions with ezrin in MDA-MB-231 cells. Endogenous co-immunoprecipitation was used to validate protein-protein interactions between ezrin and p65 in MDA-MB-231. Exogenous interactions between ezrin and p65 were validated in MDA-MB-231 cells via Flag-ezrin and HA-p65 co-transfection and followed by co-immunoprecipitation. Immunofluorescence staining was used to visualize ezrin and p65 co-localization in MDA-MB-231. LCMS results showed that there were 1000 proteins interacting with ezrin in MDA-MB-231 cells. Ezrin and p65 interactions were confirmed with both endogenous and exogenous methods. We were also able to visualize ezrin and p65 co-localization in MDA-MB-231. In summary, we found protein-protein interactions between Ezrin and p65 in human breast cancer cells.