PD-L1 (CD274) and PD-L2 (PDCD1LG2) promoter methylation is associated with HPV infection and transcriptional repression in head and neck squamous cell carcinomas

Abstract

BackgroundDNA methylation of the immune checkpoint gene PD-L1 has recently been shown to be associated with PD-L1 mRNA expression in various malignancies. This study aimed to investigate the association of PD-L1 and PD-L2 methylation with mRNA expression, immune cell infitration, protein expression and human papilloma virus (HPV) infection in head and neck squamous cell carcinoma (HNSCC) patients.ResultsDNA methylation of PD-L1 and PD-L2 correlates inversely with mRNA expression (PD-L1: p ≤ 0.002; PD-L2: p ≤ 0.014). Methylation of specific CpG-sites of both PD-L1 and PD-L2 were further significantly associated with HPV infection in the TCGA cohort. Immune cell infiltrates correlated significantly with PD-L1 and PD-L2 methylation. In the validation cohort, PD-L1 protein expression was associated with PD-L1 hypomethylation (p = 0.012).ConclusionsDNA methylation of PD-L1 and PD-L2 is associated with transcriptional silencing and HPV infection in HNSCCs. Additional studies are warranted to test PD-L1 and PD-L2 methylation as predictive biomarkers for response to immunotherapies (e.g. pembrolizumab and nivolumab) that target the PD-L1/PD-L2/PD-1 immune checkpoint axis.Materials and MethodsPD-L1 and PD-L2 promoter methylation and its mRNA expression were analyzed based on Infinium HumanMethylation450 BeadChip and RNA-Seq (both Illumina, Inc.) data in a representative HNSCC patient cohort (n = 528) enrolled by The Cancer Genome Atlas (TCGA) Research Network. A validation cohort consisting of 168 HNSCC patients treated at the University Hospital Bonn was analyzed regarding PD-L1 and PD-L2 promoter methylation by means of methylation-specific quantitative real-time PCR. PD-L1 protein expression in the validation cohort was quantified via immunohistochemistry (PD-L1 antibody clone 22C3, Dako/Agilent Technologies, Inc.).

<p>Ultrasound-Mediated Co-Delivery of miR-34a and sPD-1 Complexed with Microbubbles for Synergistic Cancer Therapy</p>

“…sPD-1 has been reported to reduce IFN-γ-mediated immunosuppression. 36 In our study we found that the level of IFN-γ was increased in miR-34a/CLMBs group and sPD-1/CLMBs group, especially in simultaneous injection of miR-34a/CLMBs and sPD-1/CLMBs groups.…”

PD-1 (PDCD1) Promoter Methylation Is a Prognostic Factor in Patients With Diffuse Lower-Grade Gliomas Harboring Isocitrate Dehydrogenase (IDH) Mutations

“…Elucidating the regulatory machinery of immune checkpoints might help to improve patient's treatment, particularly in the view of emerging immunotherapeutic strategies. Recently, inverse correlations between immune checkpoint mRNA levels and promoter methylation indicative of an epigenetic regulation as well as significant associations of immune checkpoint methylation levels with survival have been reported for several hematopoietic and solid neoplasms including acute myeloid leukemia (AML), prostate cancer, colorectal adenocarcinomas, and head and neck squamous cell carcinomas (HNSCC) ( Franzen et al, 2018 , Gevensleben et al, 2016 , Goltz et al, 2016a , Goltz et al, 2016b , Goltz et al, 2017a , Goltz et al, 2017b ). However, epigenetic association studies regarding tumors of the central nervous system are lacking so far.…”

Humanized Mice as an Effective Evaluation System for Peptide Vaccines and Immune Checkpoint Inhibitors

“…Viral infections do not always enhance PD-L1 expression, because similar PD-L1 levels are detected in individuals not infected with viruses [61][62][63][64]. Increased PD-L1 levels are related to specific viruses, such as the following: Epstein-Barr virus (EBV) [65][66][67][68], hepatitis B virus (HBV) [69][70][71], hepatitis C virus (HCV) [72][73][74][75], human immunodeficiency virus (HIV) [63,[76][77][78][79], human papilloma virus (HPV) [68,[80][81][82][83], Merkel cell polyomavirus (MCPyV) [84], bovine leukemia virus (BLV) [85], and Kaposi sarcoma-associated herpes virus (KSHV) [86].…”