DAPT suppresses proliferation and migration of hepatocellular carcinoma by regulating the extracellular matrix and inhibiting the Hes1/PTEN/AKT/mTOR signaling pathway

The aim of the present study was to investigate the antitumor properties of N-(N-[3,5-difluorophenacetyl]-1-alanyl)-S-phenylglycine t-butyl ester (DAPT) against hepatocellular carcinoma (HCC), as well as the underlying mechanism.Immunohistochemistry and quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay were used to determine the expression of Notch1 in HCC tissues. The expression of Notch1 in 3 HCC cell lines was evaluated by qRT-PCR and Western blot. The proliferation ability of cells was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and colony formation assays. Flow cytometry and Transwell assay were used to check the apoptosis and migration of HepG2 cells, respectively. Western blot was used to determine the expression level of Notch1, Hes1, Phosphatase and tensin homolog (PTEN), protein kinase B1 (AKT1), phosphorylated AKT1, mammalian target of rapamycin (mTOR), phosphorylated mTOR, intracellular adhesion molecule-1, vascular cell adhesion protein 1, matrix metalloproteinase (MMP)-2, MMP-9, and focal adhesion kinase in cells and tumor tissues. A HepG2 xenograft experiment was conducted to evaluate the in vivo antitumor properties of DAPT.Notch1 was found to be significantly upregulated in both HCC tissues and cell lines. DAPT significantly inhibited the proliferation and migration of HepG2 cells in a dose-dependent manner, accompanied by the suppression of Notch1/Hes1 signaling, inactivation of AKT/mTOR signaling, downregulation of MMPs, and decreased expression of adhesion molecules. The activation of Notch1/Hes1 or AKT/mTOR signaling removed the inhibitory effect of DAPT on the proliferation and migration of HepG2 cells, as well as the inhibitory properties of DAPT on the expression of MMPs and adhesion molecules. The antitumor properties and regulatory effect of DAPT against the extracellular matrix (ECM) and Hes1/PTEN/AKT/mTOR signaling were verified by the HepG2 xenograft experiments.DAPT could suppress the proliferation and migration of HCC by regulating the ECM and inhibiting the Hes1/PTEN/AKT/mTOR signaling pathway.