Epigenetic regulations in the IFNγ signalling pathway: IFNγ-mediated MHC class I upregulation on tumour cells is associated with DNA demethylation of antigen-presenting machinery genes [TC1A9_IFN]

Reversible MHC class I deficiency on tumour cells is commonly caused by coordinated silencing of antigen-presenting machinery genes and restorable by IFNγ. Here we describe association of DNA demethylation of selected antigen-presenting machinery gene regulatory regions located in the MHC genomic locus (TAP-1, TAP-2, LMP-2, LMP-7) upon IFNγ treatment with MHC class I upregulation on tumour cells. Our novel findings demonstrate that IFNγ acts as an epigenetic modifier upregulating the expression of antigen-presenting machinery genes through DNA demethylation. Our data also cast more light on the role of DNA methylation in tumour cell escape from specific immunity. TC-1/A9 cultured cells treated with IFN gama or nothing. 3 biological replicates per condition.