Abstract
Background:
Predictive biomarkers for anti-programmed cell death-1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) therapy are needed. Here, we validated the role of PD-1 single nucleotide polymorphisms (SNPs) in predicting the development of immune-related adverse events (irAEs) in patients with advanced cancer treated with anti-PD-1/PD-L1-based immunotherapy and defined the molecular mechanisms underlying the role of identified SNP candidate.
Methods:
Blood samples, clinical-pathological characteristics, survival outcomes and irAEs were collected from two cohorts of patients: (1) patients with advanced cancer treated with anti-PD-1/PD-L1 alone and (2) patients with advanced non-small cell lung cancer (NSCLC) treated with anti-PD-1 in combination with platinum-based chemotherapy with or without anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) therapy. PD-1 SNPs including rs2227981, rs7421861, rs11568821, rs36084323, rs2227982 and rs10204525 were genotyped and correlated with clinical-pathological characteristics and irAEs. Putative miRNAs binding to PD-1 SNP candidate were identified by in silico analysis. Validation of miRNA binding to PD-1 SNP allele specificity as well as evaluation of the induced PD-1 modulation was performed in vitro using patient-derived peripheral blood mononuclear cells (PBMCs). Susceptibility of non-cancer cells to immune cells incubated with anti-PD-1 based on PD-1 SNP allele specificity and miRNA modulation was performed by co-culturing non-cancer human epidermal keratinocyte (HaCaT) cells and bronchial epithelial BEAS-2B cells with human leukocyte antigen (HLA)-matched PBMCs, obtained from patients with cancer treated with anti-PD-1/PD-L1-based immunotherapy and carrying a different PD-1 SNP.
Results:
Most of the analyzed PD-1 SNPs were not associated with the development of irAEs. In contrast, rs10204525 exhibited a significant association with the occurrence of both grade 1-2 and 3-4 irAEs in both cohorts of patients. Specifically, patients carrying C/C had a higher rate of irAEs as compared with those carrying C/T. rs10204525 mapped on 3' untranslated region (3'-UTR) region of PD-1. miR-4717-3p bound to rs10204525 based on its allele specificity. Modulation of miR-4717-3p expression as well as of miR-4717-3p binding to rs10204525 differentially regulated PD-1 expression and induction in PMBCs harboring C/C or C/T genotypes as well as their ability to recognize and destroy HLA-matched HaCaT cells, even more in the presence of anti-PD-1 therapy. Specifically, PBMCs carrying a C/T genotype displayed a significantly lower ability to recognize and destroy non-cancer cells as compared to those carrying C/C. These results were further validated by co-culturing of both BEAS-2B and HaCaT non-cancer cells with PBMCs carrying differential rs10204525 genotypes, isolated from additional patients with cancer, incubated with anti-PD-1 or anti-PD-1 in combination with anti-CTLA-4 therapy.
Conclusions:
These findings have high clinical relevance since they define rs10204525 binding to miR-4717-3p-mediated PD-1 expression and induction as a mechanism modulating the reactivity of immune cells to non-cancer cells as well as a novel biomarker for predicting irAEs in patients with advanced cancer treated with anti-PD-1/PD-L1-based immunotherapy.