Related Experiment Video
Updated: Aug 5, 2025
Using 22C3 Anti-PD-L1 Antibody Concentrate on Biopsy and Cytology Samples from Non-small Cell Lung Cancer Patients
Published on: September 25, 2018
Examination of the Functional Relationship between PD-L1 DNA Methylation and mRNA Expression in Non-Small-Cell Lung
Trine V Larsen1, Nina Dybdal1, Tina F Daugaard1
1Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark.
Abstract:
Immunotherapy targeting the interaction between programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) is a treatment option for patients with non-small-cell lung cancer (NSCLC). The expression of PD-L1 by the NSCLC cells determines treatment effectiveness, but the relationship between PD-L1 DNA methylation and expression has not been clearly described. We investigated PD-L1 DNA methylation, mRNA expression, and protein expression in NSCLC cell lines and tumor biopsies. We used clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR-Cas9) to modify PD-L1 genetic contexts and endonuclease deficient Cas9 (dCas9) fusions with ten-eleven translocation methylcytosine dioxygenase 1 (TET1) and DNA (cytosine-5)-methyltransferase 3A (DNMT3A) to manipulate PD-L1 DNA methylation. In NSCLC cell lines, we identified specific PD-L1 CpG sites with methylation levels inversely correlated with PD-L1 mRNA expression. However, inducing PD-L1 mRNA expression with interferon-γ did not decrease the methylation level for these CpG sites, and using CRISPR-Cas9, we found that the CpG sites did not directly confer a negative regulation. dCas9-TET1 and dCas9-DNMT3A could induce PD-L1 hypo- and hyper-methylation, respectively, with the latter conferring a decrease in expression showing the functional impact of methylation. In NSCLC biopsies, the inverse correlation between the methylation and expression of PD-L1 was weak. We conclude that there is a regulatory link between PD-L1 DNA methylation and expression. However, since these measures are weakly associated, this study highlights the need for further research before PD-L1 DNA methylation can be implemented as a biomarker and drug target for measures to improve the effectiveness of PD-1/PD-L1 immunotherapy in NSCLC.
Insights
Investigating programmed death-ligand 1 (PD-L1) DNA methylation in non-small-cell lung cancer (NSCLC) reveals a regulatory link to its expression. However, the weak association suggests further research is needed before using PD-L1 methylation as a biomarker for immunotherapy.
Area of Science:
- Oncology
- Molecular Biology
- Immunology
Background:
- Immunotherapy targeting programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) interaction is crucial for non-small-cell lung cancer (NSCLC) treatment.
- PD-L1 expression levels in NSCLC cells are key determinants of treatment efficacy.
- The precise relationship between PD-L1 DNA methylation and its expression remains incompletely understood.
Purpose of the Study:
- To investigate the correlation between PD-L1 DNA methylation, mRNA expression, and protein expression in NSCLC.
- To explore the functional impact of PD-L1 DNA methylation using gene editing technologies.
- To assess the potential of PD-L1 DNA methylation as a biomarker for PD-1/PD-L1 immunotherapy effectiveness in NSCLC.
Main Methods:
- Analysis of PD-L1 DNA methylation, mRNA, and protein expression in NSCLC cell lines and tumor biopsies.
- Utilized clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR-Cas9) for genetic modification.
- Employed dCas9 fusions with TET1 and DNMT3A to manipulate PD-L1 DNA methylation levels.
Main Results:
- Identified specific CpG sites in NSCLC cell lines where methylation inversely correlated with PD-L1 mRNA expression.
- Demonstrated that interferon-γ induction of PD-L1 expression did not alter methylation at these sites.
- Showcased functional impact of methylation: dCas9-DNMT3A induced hyper-methylation and decreased PD-L1 expression, while dCas9-TET1 induced hypo-methylation.
- Observed a weak inverse correlation between PD-L1 methylation and expression in NSCLC biopsies.
Conclusions:
- Established a regulatory link between PD-L1 DNA methylation and its expression in NSCLC.
- The weak association between methylation and expression in clinical samples indicates limitations for current biomarker applications.
- Further research is essential to determine the utility of PD-L1 DNA methylation as a biomarker and drug target for enhancing PD-1/PD-L1 immunotherapy outcomes in NSCLC.
More Related Videos
06:03Orthotopic Transplantation of Syngeneic Lung Adenocarcinoma Cells to Study PD-L1 Expression
Published on: January 19, 2019
07:47Author Spotlight: Unveiling Transmembrane Protein Family-Related Markers in Gastric Cancer and Implications for Targeted Therapies
Published on: September 15, 2023
Related Concept Videos
01:37Epigenetic Regulation
X-chromosome...
01:22MicroRNAs
02:39lncRNA - Long Non-coding RNAs
02:23Abnormal Proliferation