Tumor Environment Promotes Lnc57Rik-Mediated Suppressive Function of Myeloid-Derived Suppressor Cells.

Myeloid-derived suppressor cells (MDSCs) are pathologically activated neutrophils and monocytes with potent immunosuppressive activity that regulate immune responses in the tumor microenvironment. We identified a novel long noncoding RNA (lncRNA), named as , in the MDSCs that controls their immunosuppressive functions. was induced in in vitro and in vivo inflammatory settings and upregulated the genes related to MDSC-mediated immunosuppression, including , , , and Furthermore, can not only bind with the C/EBPβ isoform liver-enriched activator protein to activate C/EBPβ but also with the methyltransferase WD repeat-containing protein 5 that enables the enrichment of histone H3 trimethylated lysine 4 marks on the promoter regions of , , , and , eventually resulting in their transcriptional activation. Furthermore, the conserved human has a similar function as murine Taken together, upregulation of in the tumor microenvironment promotes the immunosuppressive function of MDSCs.