Inhibition of hypoxia-inducible factor-1α by PX-478 as a potential targeted therapy in ESCC.

Abstract

e14083 Background: Hypoxia is a unique microenvironment in solid tumors, including ESCC. We aim to investigate the interaction between hypoxia-inducible factor-1α (HIF-1α), COX-2 and programmed cell death ligand-1 (PD-L1) and uncover the role of HIF-1α inhibitor PX-478 as a potential targeted therapy in ESCC. Methods: Immunohistochemical staining was performed to investigate the levels of HIF-1α, COX-2 and PD-L1 from 133 pT3N0M0 ESCC patients after radical resection. The prognostic value of the expression of HIF-1α, COX-2 and PD-L1 and the correlation with clinicopathologic features was evaluated. Knockdown assay, CCK-8 assay, Western blot, real-time polymerase chain reaction (RT-PCR), flow cytometry and Transwell migration assays were used in cells experiment. Results: HIF-1α and PD-L1 are independent prognostic factors in pT3N0M0 ESCC. Further data showed that HIF-1α plays an important role in regulation of COX-2 and PD-L1 expression. Our in vitro studies demonstrated that HIF-1α inhibitor, PX-478, induced G2 phase arrest, increased apoptosis, and inhibited migration and invasion of esophageal carcinoma cells, and thus significantly inhibit ESCC cells proliferation. Conclusions: Our results provide new insight into the potential role of HIF-1α inhibitors, PX-478 and open up the possibility of PX-478 for targeted therapy of ESCC.