miR-122/NEGR1 axis contributes colorectal cancer liver metastasis by PI3K/AKT pathway and macrophage modulation.

Colorectal cancer (CRC) is a prevalent malignant tumor in the gastrointestinal tract, with around 50% of patients experiencing distant metastases, predominantly to the liver. Colorectal cancer liver metastasis (CRLM) is a leading cause of CRC-related death, and effective treatments remain limited. This study aims to identify new targets for predicting and treating CRLM. Bioinformatics analysis highlighted the miR-122/NEGR1 axis as crucial in CRLM. In vitro assays (Colony formation, Wound healing, Transwell) explored the impact of this axis on CRC cell proliferation, invasion, and migration. Dual-Luciferase Reporter Gene Assay and RNA-pulldown confirmed miR-122/NEGR1 interaction. In vivo, CRLM model mice were used to investigate the axis's effects on tumor metastasis and macrophage polarization. Immunofluorescence (IF), Quantitative Real-time PCR (qRT-PCR), Enzyme-linked Immunosorbent Assay (ELISA), and Western Blot (WB) analyzed macrophage polarization markers and cytokine/protein/RNA expression. Results showed increased miR-122 and decreased NEGR1 in liver metastases compared to primary tumors. The miR-122/NEGR1 axis enhanced CRC cell proliferation, migration, invasion, and affected the PI3K/AKT pathway. Furthermore, reduced NEGR1 promoted M2 macrophage polarization and accelerated liver metastasis in CRLM model mice. In conclusion, the miR-122/NEGR1 axis drives CRC progression and liver metastasis through the PI3K/AKT pathway and M2 macrophage polarization, representing a potential target for the therapy of CRLM.