Tracking the evolution of circulating exosomal-PD-L1 to monitor melanoma patients. Issue 1 (1st January 2020)

• Record Type: Journal Article
• Authors: Cordonnier, Marine; Nardin, Charlée; Chanteloup, Gaëtan; Derangere, Valentin; Algros, Marie-Paule; Arnould, Laurent; Garrido, Carmen; Aubin, François; Gobbo, Jessica
• Is Part Of: Journal of extracellular vesicles. Volume 9:Issue 1(2020)
• Publication Date: 2020-01-01
• Subjects: Melanoma -- exosome -- PD-L1/PD-1 -- immune checkpoint -- follow-up; Cells -- Mechanical properties -- Periodicals; Transport Vesicles; Cells -- Mechanical properties; Periodicals; Fulltext; Internet Resources; Periodicals; Electronic journals; Periodicals; 571.63
• DOI: 10.1080/20013078.2019.1710899
• Languages: English
• ISSNs: 2001-3078

Abstract

ABSTRACT: In the era of immunotherapies there is an urgent need to implement the use of circulating biomarkers in clinical practice to facilitate personalized therapy and to predict treatment response. We conducted a prospective study to evaluate the usefulness of circulating exosomal-PD-L1 in melanoma patients' follow-up. We studied the dynamics of exosomal-PD-L1 from 100 melanoma patients by using an enzyme-linked immunosorbent assay. We found that PD-L1 was secreted through exosomes by melanoma cells. Exosomes carrying PD-L1 had immunosuppressive properties since they were as efficient as the cancer cell from which they derive at inhibiting T-cell activation. In plasma from melanoma patients, the level of PD-L1 (n= 30, median 64.26 pg/mL) was significantly higher in exosomes compared to soluble PD-L1 (n= 30, 0.1 pg/mL). Furthermore, exosomal-PD-L1 was detected in all patients whereas only 67% of tumour biopsies were PD-L1 positive. Although baseline exosomal-PD-L1 levels were not associated with clinic-pathologic characteristics, their variations after the cures (ΔExoPD-L1) correlated with the tumour response to treatment. A ΔExoPD-L1 cut-off of> 100 was defined, yielding an 83% sensitivity, a 70% specificity, a 91% positive predictive value and 54% negative predictive values for disease progression. The use of the cut-off allowed stratification in two groups of patients statistically different concerning overall survival and progression-free survival. PD-L1 levels in circulating exosomes seem to be a more reliable marker than PD-L1 expression in tumour biopsies. Monitoring of circulating exosomal-PD-L1 may be useful to predict the tumour response to treatment and clinical outcome.