Impact of COX2 inhibitor for regulation of PD-L1 expression in non-small cell lung cancer

Abstract

Background/Aim: There is no clear evidence in the literature regarding the regulation of programmed cell death-ligand 1 (PD-L1) expression by cyclo-oxygenase-2 (COX2). In this study, whether PD-L1 expression was regulated by COX2 activity was examined in vitro. Materials and Methods: Resected lung cancer specimens were analyzed for PD-L1 and COX2 expression by immunohistochemical analysis. Next, co-localization of PDL1 and COX2 expression was analyzed by doublefluorescence staining. Lastly, the effect of COX2 inhibition on the expression of PD-L1 was examined using lung cancer cell lines. Results: PD-L1 expression was significantly correlated with COX2 expression in the resected specimens. The majority of cancer cells that expressed PD-L1 also coexpressed COX2. However, treatment of lung cancer cell lines with a COX2 inhibitor had no impact on PD-L1 expression. Conclusion: Our results suggest that COX2 inhibition might have no effect on the usage of immune checkpoint inhibitors in lung cancer treatment.