Abstract
Background: Since intrinsic PD-1 receptor functions promote tumor growth was reported, we will investigate the role of PD-L1 in lung adenocarcinoma cells, and their impact on clinical ...outcome.
Materials and methods: Lung adenocarcinoma CL1-5 cells, derived from CL1-0 cells have more invasive ability. We prepared PDL1-overexpression human lung adenocarcinoma cell line, derived from CL1-0 cells (CL1-0-PD1) and from PC14PE6 cells (PC14PE6-PD-L1). We observed the cellular morphology, and invasiveness; epithelial-mesenchymal transition (EMT) markers and regulators were also evaluated. To explore interaction between PD-1 and PD-L1, we treated the CL1-0, CL1-5, CL1-0-PDL1 cells, PC14PE6 cells, and PC14PE6-PD-L1 cells with anti-PD-1 antibody, and then evaluated cellular invasion. We also suppressed PD-1 to test whether PD-1/PDL-1 interaction contributed to the EMT change. Further, we evaluated cellular proliferation and chemosensitivity by MTT assay and colony formation assay. Finally, we correlated PD-L1 expression with clinical outcome in patients’ tumor specimen.
Results: CL1-5 cells possessed higher PD-L1 expression than parental CL1-0 cells. CL1-0 cells with PD-L1 overexpression had more expression of EMT regulators and mesenchymal markers. Overexpression of PD-L1 in another lung adenocarcinoma PC14PE cells (PC14PE6-PD-L1 cells) become more aggressive. On the contrary, down-regulation of PD-L1 in CL1-5 cells and PC14-PE6-PD-L1 cells became indolent. Besides through the observation from confocal microscopy, PD-L1 expression was more co-localized with vimentin and slug, individually in CL1-5, CL1-0-PD-L1 and PC14PE6-PD-L1 cells. Therefore, PD-L1 promoted EMT in human lung adenocarcinoma cells. After adding anti-PD-1 antibody in CL1-5, CL1-0, and CL1-0-PDL1 cells, migration and invasion ability were decreased. Similar phenomenon was found when PD-1 antibody treatment in PC14PE6 cells, and PC14PE6-PD-L1 cells. Silencing PD-1 by siRNA also disrupt the cellular aggressivenss in CL1-0-PD-L1 and PC14PE6-PD-L1 cells. These results indicated PD-1/PD-L1 axis regulated cancer cells migration and invasiveness. PD-L1 expression also decreased cellular proliferation and had little influence on chemsensitivity. Finally, we found that higher PD-L1 expression was correlated with lymph node metastasis in clinical specimen.
Conclusion: Lung adenocarcinoma cells with higher PD-L1 expression promote EMT via PD-1 receptor. PD-L1 expression lowers proliferation rate, but has little impact on chemosensitivity. Lung cancer patients with high PD-L1 expression in tumor have higher lymph node metastasis.
Citation Format: Wen-Pin Su, Li-Chan Chang, Jing-Jou Yan, Wu-Chou Su. PD-1/PD-L1 axis in cancer cells contributes to cellular EMT in lung adenocarcinoma abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4599.
Blockade of the PD-1/PD-L1 axis using antibody drugs has been a clinically efficacious immunotherapy in cancer treatment. However, studies on peptide inhibitors blocking the interaction between ...PD-1/PD-L1 in cancer treatment in clinical practice have not yet been reported. In this study, a series of peptide inhibitors were synthesized based on a continuous sequence of 14 amino acids from PD-L1 and suitable modifications to form a hairpin structure. The effect of inhibitors on the blockage of PD-1/PD-L1 by increasing the stability of the hairpin structure was determined using BLI and co-culture models. The results showed that increasing the stability of the hairpin improved the affinity of inhibitors to PD-1 and increased IL-2 secretion. Therefore, modifying the hairpin structure of peptide inhibitors may be a useful approach to block the interaction between PD-1 and PD-L1.
•P1.1 was examined.•Stabilizing the hairpin increased the affinity to PD-1 and IL-2 secretion, while decreasing the stability does not.•Compared to P1.1, decreasing the stability of the hairpin inhibited the affinity of inhibitors to PD-1 and IL-2 secretion.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
