The Effect And Mechanism Of Chemokine Receptor CCR6 In Tumor Angiogenesis In Colorectal Cancer

Objective: To investigate the effect and mechanism of chemokine receptor CCR6 in tumor angiogenesis in colorectal cancer(CRC).Methods: The expression of CCR6 in CRC tissues and adjacent normal tissues was detected by semi-quantitative PCR,western blot and immunohistochemical staining(IHC).And we analyzed the relationship between CCR6 expression and some clinicopathological features.The CCR6 knockdown and overexpression of CRC cells were constructed by lentiviral transfection.The effect of CCR6 on CRC angiogenesis was evaluated by endothelial tube formation assay.The effects of CCR6 on the proliferation and migration of human umbilical vein endothelial cells(HUVECs)were evaluated by Ed U and transwell assay.By semiquantitative PCR,we found the downstream signal molecule VEGF-A which mediated CCR6-induced angiogenesis,which was verified by western blot and enzyme linked immunosorbent assay(ELISA).Furthermore,the deeper molecular mechanism of CCR6 regulating CRC angiogenesis was revealed.Subcutaneous xenotransplanted tumor models and IHC evaluated the effect of CCR6 on angiogenesis in vivo.Results: CCR6 expression levels were significantly increased in CRC tissues compared with adjacent normal tissues.In a retrospective cohort,a significant association was observed between the CCR6 negative group and positive group in invasion depth and metastasis.Kaplan–Meier survival curves showed a strong correlation between high CCR6 level and poorer 5-year overall survival(OS)and disease-free survival(DFS).Endothelial tube formation assay showed that CCR6 promoted angiogenesis because overexpression of CCR6 promoted the proliferation and migration of HUVECs.A semi-quantitative RT-PCR was then performed,VEGF-A was selected for further investigation because of its largest up-regulation.We further demonstrated that the effect of CCR6 was dependent on the activation of AKT/NF-?B/VEGF pathway.CCR6 also promoted the growth and angiogenesis of CRC in vivo.Conclusion: Chemokine receptor CCR6 facilitates angiogenesis of CRC by activating AKT/NF-?B/VEGF pathway.Overexpression of CCR6 is correlated with poor survival of CRC patients.