NEK2 promotes colorectal cancer progression by activating the TGF-β/Smad2 signaling pathway

Colorectal cancer (CRC) is a prevalent malignancy with poor patient survival, and NIMA-associated kinase 2 (NEK2) has been implicated in the pathogenesis and progression of various cancers, including CRC. This study aimed to investigate the impact of NEK2 on CRC cell functionality and its interaction with the TGF-β/Smad signaling pathway. NEK2 expression in CRC tissues and cell lines was assessed, and its association with patient survival was analyzed. Functional assays, including NEK2 knockdown via lentiviral infection, RT-qPCR, Western blotting, CCK-8 assay, Transwell migration, invasion assays, and goblet cell formation assays, were employed to evaluate NEK2′s effects on CRC cell proliferation, migration, invasion, and stemness. Mechanistic studies explored the TGF-β/Smad2 signaling pathway, utilizing co-immunoprecipitation (Co-IP) and protein interaction analyses. In vivo experiments further evaluated NEK2′s role in tumor initiation, metastasis, and chemoresistance. NEK2 was found to be upregulated in CRC tissues and correlated with poor survival. NEK2 knockdown inhibited CRC cell behaviors, while NEK2 activated the TGF-β/Smad2 signaling pathway through Smad2/3 phosphorylation. Overexpression of Smad2/3 reversed NEK2 knockdown effects, confirming the importance of this pathway in CRC. In vivo, NEK2 promoted tumor initiation, metastasis, and chemoresistance, effects partially reversed by Smad2/3 overexpression. These findings reveal the critical role of NEK2 in CRC progression and underscore its potential as a therapeutic target, offering new insights into the molecular mechanisms driving CRC and informing targeted therapy development.