P2RX1-blocked neutrophils induce CD8+ T cell dysfunction and affect the immune escape of gastric cancer cells.

Background: Gastric cancer (GC) is one of the deadly malignancies of the gastrointestinal tract. Research has confirmed the linkage of P2RX1 with immune cell activation and tumor progression. This project focused on the impact of P2RX1 level in neutrophils on the efficacy of immune checkpoint inhibitor (ICI) treatment in GC.

Methods: Blood samples from 23 GC patients eligible for camrelizumab treatment were collected. Flow cytometry was carried out to analyze the proportion of P2RX1 in neutrophils. IHC was utilized to detect the expression level of PD-L1. We also evaluated the chemotaxis ability of neutrophils using a Transwell system, assessed the viability and apoptosis rate of GC cells using CCK-8 and flow cytometry, measured the proportions of CD8⁺PD-1⁺ and CD8⁺GZMB⁺ cells, determined the expression levels of IL-6, TNFα, IFN-γ, IL-8, IL-12, IL-1β, and GZMB by utilizing enzyme-linked immunosorbent assay (ELISA), and examined the expression levels of P2RX1 and PD-L1 using western blot (WB). By establishing a xenograft mouse model, we studied the impact of P2RX1-blocked neutrophils on the efficacy of ICI treatment in the GC microenvironment.

Results: In GC, clinical analysis revealed increased infiltration of P2RX1-lowly expressed neutrophil subsets and increased expression of PD-L1. In vitro experiments demonstrated that abnormal expression of P2RX1 affected neutrophil function. Furthermore, the blockage or knockdown of P2RX1 in neutrophils modulated CD8⁺ T cell function, promoting GC progression. In in vivo experiments, the blockage of P2RX1 in neutrophils inhibited the effectiveness of ICI treatment in the GC microenvironment.

Conclusion: This project validated that the loss of P2RX1 in neutrophils induces CD8⁺ T cell dysfunction and affects the GC development, indicating that P2RX1 may be an accurate biomarker for predicting ICI response, thus providing a theoretical basis for the clinical application of ICI.