NSUN5 promotes tumorigenic phenotypes through the WNT signaling pathway and immunosuppression of CD8+ T cells in gastric cancer

NSUN5, a key member of the M5C methylation family, plays a significant role in fundamental biological processes like cell proliferation and differentiation. However, its specific function and mechanisms in gastric cancer remain insufficiently understood. Initially, we examined NSUN5's differential expression in gastric cancer versus normal tissues, along with survival trends, associated signaling pathways, and immune infiltration using the TCGA database. Subsequently, we conducted immunohistochemistry experiments to assess NSUN5 expression in gastric cancer tissues. Gain-and loss-of-function experiments were carried out to investigate NSUN5's impact on the proliferation, stemness, and migratory capabilities of gastric cancer cells, as well as the expression of vital proteins in pertinent signaling pathways. Our findings demonstrate that NSUN5 is not only overexpressed in gastric cancer tissues, but also positively associated with tumor stage and inversely linked with patient prognosis. NSUN5 promotes the in vitro proliferation, stemness, and migration of gastric cancer cells, and the in vivo growth of these cells, chiefly through the activation of the WNT/β-catenin signaling pathway. Additionally, NSUN5 appears to diminish the infiltration of CD8+ T cells in gastric cancer, contributing to immune evasion. In conclusion, NSUN5 functions as a proto-oncogene in the progression of gastric cancer and may serve as a potential therapeutic target.