P2RX1-Negative Neutrophils Promote the Immunosuppressive Microenvironment in Non-Small Cell Lung Cancer by Upregulating PD-L1 Expression

BACKGROUND:The most abundant innate immune cells, neutrophils, contribute significantly to cancer development by stimulating immunosuppression. However, it remains unclear about its function and molecular mechanisms in the immunosuppressive microenvironment of non-small cell lung cancer (NSCLC). METHODS:Blood samples were collected from NSCLC patients and healthy volunteers to detect the expression of P2RX1 and PD-L1 in neutrophils using qRT-PCR, western blot (WB), and flow cytometry. Neutrophils were sorted into P2RX1-positive (P2RX1+)/P2RX1-negative (P2RX1-) groups and co-cultured with CD8+ T cells. Changes in the proliferative and cytotoxic capabilities of CD8+ T cells were then detected using flow cytometry and enzyme-linked immunosorbent assay. The content of granzyme B was determined by enzyme-linked immunosorbent assay. The effects of P2RX1-deficient neutrophils on fatty acids, triglycerides, lipid droplet content and FASN expression were detected using kits, Nile red staining and WB, respectively. RESULTS:This study revealed a deficiency in P2RX1 expression in peripheral blood neutrophils of NSCLC patients, which was negatively correlated with the expression of PD-L1. P2RX1-neutrophils inhibited T cell proliferation and granzyme B expression and promoted T cell exhaustion. Furthermore, in P2RX1-deficient neutrophils, there was a notable increase in the levels of fatty acids, triglycerides, and lipid droplet accumulation, as well as an upregulation of FASN protein expression. Mechanistically, P2RX1-neutrophils upregulated PD-L1 expression by inducing fatty acid metabolism to improve immunosuppression in NSCLC. CONCLUSION:The mechanism by which P2RX1-deficient neutrophils contributed to immunosuppressive effects in NSCLC was clarified by our findings, indicating that P2RX1 could be one potential target for counteracting the immunosuppressive effects of neutrophils.