PD-L1 overexpression, SWI/SNF complex Deregulation and Profound Transcriptomic Changes Characterize Cancer-Dependent Exhaustion of Persistently Activated CD4+ T Cells

ABSTRACT: The growing tumor avoids recognition and destruction by immune system. During continuous stimulation of tumor infiltrating lymphocytes (TILs) by tumor, TILs become functionally exhausted. Thus, they become unable to kill tumor cells and to produce some cytokines, and lose their ability to proliferate. It collectively results in the immune escape of cancer cells. Here, we show that breast cancer cells expressing PD-L1 can accelerate exhaustion of persistently activated human effector CD4+ T cells, manifesting in high PD-1 and PD-L1 expression level on cell surface, decreased glucose metabolism genes, strong downregulation of SWI/SNF chromatin remodeling complex subunits and p21 cell cycle inhibitor upregulation. This results in inhibition of T cell proliferation and reduction of T cells number. The RNAseq analysis on exhausted CD4+ T cells indicated strong overexpression of IDO1 and genes encoding pro-inflammatory cytokines and chemokines. The PD-L1 overexpression was also observed in CD4+ T cells after co-cultivation with other cell line overexpressing PD-L1 that suggested the existence of general mechanism of CD4+ T cell exhaustion induced by cancer cells. The ChIP analysis on PD-L1 promoter region indicated that the strong BRM recruitment in control CD4+ T cells is replaced by BRG1 and EZH2 in CD4+ T cells strongly exhausted by cancer cells. These findings suggest that such epi-drugs as EZH2 inhibitors may be used as immunomodulators in cancer treatment.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Homo Sapiens (human) Bos Taurus (bovine)

SUBMITTER: Agata Malinowska  

LAB HEAD: Michal Dadlez

PROVIDER: PXD026447 | Pride | 2022-02-17

REPOSITORIES: Pride