Imbalanced LIMK1 and LIMK2 expression leads to human colorectal cancer progression and metastasis via promoting β-catenin nuclear translocation

Epithelial–mesenchymal transition (EMT)-induced metastasis contributes to human colorectal cancer (CRC) progression, especially in advanced CRC. However, the underlying mechanism of β-catenin in this process is elusive. We identified that LIM domain kinase (LIMK)2 was progressively downregulated with tumor progression from precancerous lesions to advanced cancer. Gain- and loss-of-function assays revealed that LIMK2 inhibits cell proliferation via cell cycle arrest at the G1–S transition and suppresses the ability of cell metastasis by restricting the EMT process. Reduced LIMK2 expression enhanced the nuclear accumulation of β-catenin and activated the Wnt signaling pathway, thus contributing to tumor progression. A homolog of the LIMK family, LIMK1, which was overexpressed throughout tumor progression, served as a competitive inhibitor of LIMK2 via β-catenin nuclear translocation. The imbalanced expression of LIMK1 and LIMK2 is important in CRC progression, and the combined effects provide a new insight into the mechanism of CRC progression. These findings provide a new understanding for LIMK-based anticancer therapy.