N4BP1 is essential for the development of oral cancer via controlling both cancer cells and immune microenvironment.

N4BP1 specifically degrades a subset of mRNA targets through their coding sequences and functions as a negative regulator of inflammation; however, its role in cancer development remains undefined. N4BP1 exhibits the highest expression in head and neck squamous cell carcinoma among all analyzed cancer types. Unlike wild-type mice, N4bp1-/- mice did not develop visible tongue tumor masses in a 4-NQO-induced oral carcinogenesis model. Furthermore, N4bp1-/- mice (86% vs 0%) exhibited significantly prolonged survival compared to wild-type mice within 26 weeks in 4-NQO-induced oral carcinogenesis model. Single-cell profiling demonstrated that N4BP1-deficient epithelial cells arrest at an early stage of cancerous transformation, while wild-type epithelial cells efficiently progress to an advanced stage of cancer. In established human cancer cell lines, N4BP1 also plays a crucial role in proliferation, migration, colony formation, and in vivo growth. Transcriptome profiling identified CCL2 and GM-CSF as downstream targets of N4BP1 in oral cancer. Apart from its intrinsic role in cancer cells, N4BP1-deficient cancer cells induce the differentiation of macrophages into the M1 phenotype. In N4BP1-deficient tissues, CCL2 and GM-CSF were significantly increased, accompanied by the accumulation of M1 macrophages and neutrophils. Our results demonstrate that N4BP1 is an essential gene in tongue cancer development. N4BP1 not only drives cancer cell evolution but also establishes an immune-suppressive microenvironment. N4BP1 is an endoribonuclease that specifically regulates a subset of mRNA targets (including CCL2 and GM-CSF) and plays an essential role in oral cancer.