ONCOmmunity

Impact of COX2 Inhibitor for Regulation of PD-L1 Expression in Non-small Cell Lung Cancer.

By: Katsuhiko Shimizu, Riki Okita, Shinsuke Saisho, A I Maeda, Yuji Nojima, Masao Nakata

Department of General Thoracic Surgery, Kawasaki Medical School, Kurashiki, Japan kshimizu@med.kawasaki-m.ac.jp.
2018-06-07; doi: 10.21873/anticanres.12768

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

Resected lung cancer specimens were analyzed for PD-L1 and COX2 expression by immunohistochemical analysis. Next, co-localization of PD-L1 and COX2 expression was analyzed by double-fluorescence 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 co-expressed 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.