PD-L1 and PD-L2 immune checkpoint protein induction by type III interferon in non-small cell lung cancer cells
Trine Vilsbøll Larsen1, Tina Fuglsang Daugaard1, Hans Henrik Gad2
1Department of Biomedicine, Aarhus University, Denmark.
Introduction:
Despite the clinical success of PD-1/PD-1-ligand immunotherapy in non-small cell lung cancer (NSCLC), the appearance of primary and acquired therapy resistance is a major challenge reflecting that the mechanisms regulating the expression of the PD-1-ligands PD-L1 and PD-L2 are not fully explored. Type I and II interferons (IFNs) induce PD-L1 and PD-L2 expression. Here, we examined if PD-L1 and PD-L2 expression also can be induced by type III IFN, IFN-λ, which is peculiarly important for airway epithelial surfaces.
Methods:
In silico mRNA expression analysis of PD-L1 (CD274), PD-L2 (PDCD1LG2), and IFN- λ signaling signature genes in NSCLC tumors and cell lines was performed using RNA sequencing expression data from TCGA, OncoSG, and DepMap portals. IFN-λ-mediated induction of PD-L1 and PD-L2 expression in NSCLC cell lines was examined by real-time quantitative polymerase chain reaction and flow cytometry.
Results:
IFNL genes encoding IFN- λ variants are expressed in the majority of NSCLC tumors and cell lines along with the IFNLR1 and IL10R2 genes encoding the IFN-λ receptor subunits. The expression of PD-L1 and PD-L2 mRNA is higher in NSCLC tumors with IFNL mRNA expression compared to tumors without IFNL expression. In the NSCLC cell line HCC827, stimulation with IFN-λ induced both an increase in PD-L1 and PD-L2 mRNA expression and cell surface abundance of the corresponding proteins. In the NSCLC cell line A427, displaying a low basal expression of PD-L1 and PD-L2 mRNA and corresponding proteins, stimulation with IFN-λ resulted in an induction of the former.
Conclusion:
The type III IFN, IFN- λ, is capable of inducing PD-L1 and PD-L2 expression, at least in some NSCLC cells, and this regulation will need acknowledgment in the development of new diagnostic procedures, such as gene expression signature profiles, to improve PD-1/PD-1-ligand immunotherapy in NSCLC.
Insights
Type III interferon (IFN-λ) can induce programmed cell death protein 1 ligand 1 (PD-L1) and PD-L2 expression in non-small cell lung cancer (NSCLC) cells. This finding is crucial for developing new diagnostic tools to enhance immunotherapy for NSCLC patients.
Area of Science:
- Immunology
- Oncology
- Molecular Biology
Background:
- Immunotherapy targeting the PD-1/PD-1 ligand pathway has shown clinical success in non-small cell lung cancer (NSCLC).
- Therapy resistance remains a significant challenge, indicating incomplete understanding of PD-L1 and PD-L2 expression regulation.
- Type I and II interferons (IFNs) are known inducers of PD-L1 and PD-L2.
Purpose of the Study:
- To investigate whether type III interferon (IFN-λ) can induce PD-L1 and PD-L2 expression in NSCLC.
- To explore the role of IFN-λ in regulating PD-1 ligand expression, particularly in airway epithelial surfaces.
Main Methods:
- In silico analysis of mRNA expression data for PD-L1, PD-L2, and IFN-λ signaling genes in NSCLC tumors and cell lines using TCGA, OncoSG, and DepMap.
- Experimental validation using real-time quantitative PCR and flow cytometry to assess IFN-λ-mediated induction of PD-L1 and PD-L2 in NSCLC cell lines.
Main Results:
- IFNL genes and IFN-λ receptor subunit genes (IFNLR1, IL10R2) are expressed in most NSCLC tumors and cell lines.
- NSCLC tumors expressing IFNL mRNA exhibited higher PD-L1 and PD-L2 mRNA levels.
- IFN-λ stimulation induced increased PD-L1 and PD-L2 mRNA and protein expression in NSCLC cell lines (HCC827 and A427).
Conclusions:
- Type III interferon (IFN-λ) can induce PD-L1 and PD-L2 expression in certain NSCLC cells.
- This IFN-λ-mediated regulation of PD-1 ligands should be considered for developing novel diagnostic strategies.
- Incorporating these findings may improve the efficacy of PD-1/PD-1-ligand immunotherapy in NSCLC.
