Cigarette smoke‐mediated YTHDC2 suppression drives macrophage senescence and a tumor‐promoting microenvironment in lung cancer

Cigarette smoke is a leading cause of lung cancer, promoting disease progression through remodeling of the immune microenvironment. This study explores the impact of cigarette smoke exposure on the m 6 A reader YTHDC2, its role in inducing macrophage senescence, and the consequent formation of a tumor‐supportive inflammatory niche in lung cancer. Single‐cell RNA sequencing of lung cancer tissues revealed an enrichment of senescent macrophages with decreased YTHDC2 expression in smokers compared to non‐smokers. In vitro experiments showed that cigarette smoke extract (CSE) suppressed YTHDC2 expression in macrophages, resulting in enhanced cellular senescence, increased secretion of pro‐inflammatory cytokines and M2‐like polarization. Overexpression of YTHDC2 attenuated macrophage senescence by regulating RPS8, thereby limiting the formation of a tumor‐promoting microenvironment. In vivo studies using a cigarette smoke‐exposed lung cancer model confirmed the role of YTHDC2 in smoke‐induced immune microenvironment modulation and tumor progression. These findings identify YTHDC2 as a critical regulator of smoke‐induced macrophage senescence and the tumor‐promoting microenvironment, providing a potential therapeutic target for lung cancer in smokers.