TCN, an AKT inhibitor, exhibits potent antitumor activity and enhances radiosensitivity in hypoxic esophageal squamous cell carcinoma and .

The aim of the present study was to investigate the radiosensitization effect of triciribine (TCN) on human esophageal squamous cell carcinoma (ESCC) in normoxia or hypoxia and its mechanism. The cytotoxicity and radiosensitization mechanism of TCN were investigated by Cell Counting Kit 8, clonogenic assay, flow cytometry, western blotting (WB) and immunofluorescence staining of phospho-histone H2A.X, Ser139 (γ-H2AX) in ESCC , while the protein expression levels of AKT, phosphorylated (p)-AKT, hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) were evaluated by WB . The cytotoxicity of TCN was dose dependent. Upon exposure to TCN, ESCC cells in hypoxia treated with 4-Gy radiotherapy exhibited an evidently higher apoptotic rate than cells subjected to other treatments. TCN could significantly inhibit the protein expression of p-AKT, HIF-1α and VEGF and . The present results suggested that TCN can effectively inhibit AKT, p-AKT, HIF-1α and VEGF, thus conferring radiosensitivity to ESCC and . TCN is considered as an adjuvant in radiotherapy of ESCC in clinical application.