GSE126885
Fatty acid transporter 2 regulates lipid metabolism and suppressive function of neutrophils in cancer
Polymorphonuclear myeloid derived suppressor cells (PMN-MDSC) are pathologically activated neutrophils that accumulate in cancer and many other pathologic conditions. PMN-MDSC are critically important for the regulation of immune responses in cancer, promotion of tumor progression, and metastases. Despite the recent advances in understanding of the PMN-MDSC biology, the mechanisms responsible for pathological activation of neutrophils are not well defined, which limit selective targeting of PMN-MDSC. Here, we report that mouse and human PMN-MDSC exclusively up-regulate fatty acid transporter protein 2 (FATP2). Over-expression of FATP2 in PMN-MDSC was controlled by GM-CSF, through the activation of STAT5 transcription factor. Genetic ablation of FATP2 abrogated the suppressive activity of PMN-MDSC in spleens and tumors. FATP2 in neutrophils promoted accumulation of oxidized lipids. However, the main mechanism of FATP2 mediated suppressive activity of PMN-MDSC involved uptake of arachidonic acid and synthesis of prostaglandin E2. The selective pharmacological inhibition of FATP2 abrogated activity of PMN-MSC and substantially delayed tumor progression. In combination with check-point inhibitors it blocked tumor progression in mice. Thus, FATP2 mediates acquisition of immune suppressive activity by PMN-MDSC and represents a new target to inhibit the functions of PMN-MDSC and improve the effect of immunotherapy of cancer. Overall design: RNA-seq for WT and FATP2 KO PMN-MDSC cells