ILF2 cooperates with ILF3/KLF16 to drive colorectal cancer progression via modulating the behaviors of both tumor cells and M2 macrophages.

Colorectal cancer (CRC) is a malignant tumor originating from the epithelial cells of the colon and rectum. Interleukin enhancer binding factor 2 (ILF2), an emerging RNA-binding protein, has been implicated in the regulation of multiple cancer-related processes. However, its specific role in the pathogenesis and progression of CRC remains largely unexplored. In this study, we systematically investigated the functional role of ILF2 in CRC through multi-level experiments. ILF2 expression was first assessed in clinical CRC tissues via quantitative real-time PCR and western blot. Functional implications were further examined through gain-of-function and loss-of-function approaches. Cellular assays included CCK-8 proliferation, colony formation, Transwell migration/invasion, macrophage coculture, and flow cytometry for apoptosis, complemented by immunofluorescence staining. In vivo relevance was confirmed using xenograft models for tumor growth and metastasis. Mechanistically, Co-IP revealed a robust interaction between ILF2 and ILF3, while RIP, RNA pull-down and dual-luciferase reporter assays demonstrated direct binding of ILF3 to KLF16 mRNA, suggesting a novel regulatory axis in CRC progression. Our results demonstrated that both ILF2 mRNA and protein were significantly upregulated in colorectal cancer (CRC) tissues compared to matched peritumoral tissues. Functional assays revealed that ILF2 overexpression enhanced, whereas ILF2 knockdown suppressed, the proliferation, migration, and invasion capabilities of CRC cells in vitro. Additionally, ILF2 overexpression induced M0 macrophages to polarize toward an M2-like phenotype. Consistent with these findings, in vivo experiments indicated that ILF2 facilitated tumor growth and promoted liver metastasis in CRC. Our work suggests that ILF2 formed a complex with ILF3 to enhance the stability of KLF16 mRNA, thereby contributing to CRC progression through the regulation of KLF16.