Rab11-FIP4 regulates migration and invasion of colorectal cancer cells through IGF1R

AIM To investigate the role, clinical implications and the underlying mechanisms of Rab11-family interacting protein 4 (Rab11-FIP4) in colorectal cancer (CRC). METHODS The expression levels of Rab11-FIP4 in CRC tissues and corresponding paracancerous tissues were compared by immunohistochemistry, Western blot and RT-qPCR. The above methods were also used to detect the expression levels of Rab11-FIP4 in CRC cells under normal environment and hypoxia. The patiens were divided into Rab11-FIP4 high expression group (n=61) and Rab11-FIP4 low expression group (n=39) according to the immunohistochemical staining score.The overall survival and recurrence time of the 2 groups were compared by Kaplan-Meier survival analysis. HCT116 and LoVo cells with stable over-expression of Rab11-FIP4 were constructed using a lentiviral system. The cytological characteristics effects of Rab11-FIP4 over-expression in CRC cells were examined by CCK-8 assay, clonogenic assay and the Transwell assay. The co-immunoprecipitation was used to detect the correlation between Rab11-FIP4 and insulin-like growth factor 1 receptor (IGF1R). Human phosphokinase array was performed to investigate the signaling pathhway affected by IGF1R in CRC cells with increased expression of Rab11-FIP4. The relationship between Rab11-FIP4 and hypoxia-inducible factor 1α (HIF-1α) was analyzed by tissue microarrays and dual-luciferase reporter assay. RESULTS Rab11-FIP4 expression was up-regulated in CRC tissues and high expression of Rab11-FIP4 was associated with poor prognosis of the patients with CRC (P<0.05). Over-expression of Rab11-FIP4 promoted the viability, migration and invasion of CRC cells (P<0.05). High expression of Rab11-FIP4 regulated ERK1/2 and AKT signaling pathway via IGF1R (P<0.05). Hypoxia promoted the activation of HIF-1α on the Rab11-FIP4 promoter, thereby up-regulating the expression of Rab11-FIP4 (P<0.05). CONCLUSION Rab11-FIP4 may act as an oncogene to regulate migration and invasion of colorectal cancer cells through IGF1R.