M1-like macrophages regulate T cell infiltration in colorectal cancer through P2X4 receptor

Although tumor-associated macrophages (TAMs) play a critical immunomodulatory role in colorectal cancer (CRC), the mechanisms underlying their polarization remain unclear. This study identifies the P2X4 receptor (P2X4R) as a crucial mediator of M1-like polarization. During TAM induction in a controlled <i>in vitro</i> system using CRC cell-conditioned medium, we observed P2X4R-mediated calcium influx and subsequent mitochondrial dysfunction through immunofluorescence and mitochondrial assays. This dysfunction led to mitochondrial DNA release and subsequent activation of the cGAS-STING-IFNB1 pathway, driving M1-like polarization of TAMs. Flow cytometry demonstrated that P2X4R-expressing TAMs not only enhanced CD8⁺ T cell survival and cytotoxicity <i>in vitro</i> but also augmented T cell responses in a syngeneic CRC mouse model. Clinically, reduced P2X4 expression in CRC tissues correlated with poorer prognosis. In conclusion, these findings identify the P2X4R as a key regulator of M1-like TAM polarization, representing a promising target to reprogram TAMs and suppress CRC progression.