Global hypomethylation mediated changes regulate constitutive PD-L1 expression in melanoma [RRBS]

PD-L1 is a ligand for the inhibitory PD1 receptor on T cells and its expression in some cancers inhibits anti-cancer immune response. In melanoma, PD-L1 expression is induced in response to immune stimuli but in a proportion of melanomas it is constitutively expressed. Factors that drive constitutive expression of PD-L1 are unknown. Here we performed genome-scale methylation analysis of six cell lines that constitutively express PD-L1 (PD-L1 positive, referred to as PD-L1CON) and six cell lines that only express PD-L1 after treatment with IFN-? (PD-L1 negative, referred to as PD-L1IND) Overall design: Here we generated single-nucleotide resoultion DNA methylation map of a total of 12 cell lines using Reduced Representation Bisulfite Sequencing (RRBS). We have two groups, each with 6 cell lines each (inducible group and constitutive group)