Abstract 1234: Tumor cell-intrinsic PD-L1 promotes epithelial-to-mesenchymal transition in non-small cell lung cancer in interferon-g-independent and dependent way

Abstract

Abstract The immune checkpoint molecule programmed cell death-ligand 1 (PD-L1, CD274) suppresses immunity when the cell surface PD-L1 is engaged by programmed death-1 (PD-1) on antitumor immune cells. Although PD-L1 has been established and targeted in cancer immunotherapy, the tumor-intrinsic role of PD-L1 is less appreciated in tumor biology and therapeutic development. In this study, we showed that PD-L1 facilitates epithelial-to-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) cells by upregulating EMT transcription factors and mesenchymal markers, and downregulating epithelial marker. RNA-sequencing was performed on paired exogenously PD-L1-overexpressed A549 cells and wild-type cells, and PD-L1-depleted H460 cells and wild-type cells, and transcriptomic features associated with PD-L1 status were identified using Gene Set Enrichment Analysis (GSEA). In both the paired samples, PD-L1 expression was associated with EMT-related pathways. Subsequent in vitro experiment showed that exogenous overexpression of PD-L1 in A549 and H522 cells increased both mRNA and protein expression of Twist, Zeb1, Snail, Slug, Vimentin, Fibronectin, and N-Cadherin. Correspondingly, the transcription factors and mesenchymal markers were decreased in PD-L1-depleted H460 and H596 cells. Recombinant PD-1 treatment also increased the expression of EMT transcription factors and markers on A549 and H460 cells. Moreover, interferon-γ stimulation on tumor cells increased expression of EMT transcription factors and markers, which was suppressed by PD-L1-knockdown, suggesting that interferon-γ-induced PD-L1 contributes to EMT. Our findings suggest that PD-L1 facilitates NSCLC progression by promoting the EMT in interferon-γ-independent and dependent way, and this intrinsic PD-L1 function could be targeted for better clinical management of PD-L1-overexpressing NSCLCs. Citation Format: Hyein Jeong, Hyun Kyung Ahn, Sehui Kim, Yoon Kyung Jeon. Tumor cell-intrinsic PD-L1 promotes epithelial-to-mesenchymal transition in non-small cell lung cancer in interferon-g-independent and dependent way [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1234.