KIAA1199 promotes metastasis of colorectal cancer cells via microtubule destabilization regulated by a PP2A/stathmin pathway

Tumor metastasis is the main cause of death in advanced colorectal cancer. Our previous research showed that upregulation of KIAA1199 predicted poorer outcomes, and promoted cell motility and tumor metastasis in colorectal cancer, with the mechanisms not being fully elucidated. Here, we demonstrate that silencing of KIAA1199 results in reduced tumor metastasis in the orthotopic transplantation tumor model of colorectal cancer. Importantly, we find that KIAA1199 interacts with protein phosphatase 2A (PP2A) through the C-terminal domain and increases phosphatase activity of PP2A, which is essential for KIAA1199-mediated cell motility. Moreover, we identify stathmin, a microtubule-destabilizing protein, as a downstream of KIAA1199-PP2A complex. KIAA1199-induced dephosphorylation of stathmin results in microtubule destabilization and leads to enhanced cell motility. Furthermore, a microtubule-stabilizing drug paclitaxel could prevent KIAA1199-induced microtubule destabilization, and inhibit cell migration and invasion in vitro and tumor metastasis in vivo in colorectal cancer. Collectively, our study reveals that KIAA1199 promotes metastasis of colorectal cancer cells via microtubule destabilization regulated by a PP2A/stathmin pathway, and suggests that KIAA1199 may be a promising target for preventing metastasis in colorectal cancer.