The regulation effect of EGFR signaling pathway on PD-L1 expression on esophageal squamous cell carcinoma cell lines.

Abstract

e15577 Background: To explore the effect of radiation combined with Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors (EGFR-TKI) on the expression of PD-L1 in ESCC cell lines, and to provide theoretical support for radiotherapy combined with EGFR-TKI for esophageal cancer. Methods: Reverse transcription-polymerase chain reaction (RT-PCR) method was used to assess EGFR and PD-L1 mRNA expression on ESCC cell lines when different doses of X-ray irradiation were conducted on ESCC cell lines TE-1 and ECA-109 combining with EGFR-TKI or not. Results: In ESCC cell lines TE-1 and ECA-109, the expression of EGFR and PD-L1 mRNA was increased significantly by the activation of EGFR signaling pathway and decreased after the use of gefitinib (P > 0.01). Both EGFR (P < 0.01) and PD-L1(P < 0.01) mRNA expression of ESCC cell lines TE-1 and ECA-109 were increased by radiotherapy alone. EGFR-TKI could block the increase of both EGFR mRNA (P < 0.01) and PD-L1 mRNA (P < 0.01) which was induced by radiation. Conclusions: EGFR signaling pathway is involved in the regulation of PD-L1 expression in ESCC cell lines. Radiation could up-regulate the expression of EGFR and PD-L1 mRNA in ESCC cells which could be blocked by the use of EGFR-TKI.