Osteosarcoma is characterized by a high malignant and metastatic potential. CCL5 (previously called RANTES) was originally recognized as a product of activated T cells and plays a crucial role in the migration and metastasis of human cancer cells. It has been reported that the effect of CCL5 is mediated via CCR receptors. However, the effect of CCL5 on migration activity and integrin expression in human osteosarcoma cells is mostly unknown.Methods
Multiple molecular and pharmacological approaches such as migration assay, flow cytometric analysis, quantitative real-time PCR, western blot analysis, transfection and reporter gene assay and establishment of stably transfected cells were used to determine CCL5-regulated effect and mechanism in human osteosarcoma cell lines (U2OS and MG63).Results
We found that CCL5 increased the migration and expression of αvβ3 integrin in human osteosarcoma cells. Stimulation of cells with CCL5 increased CCR5 but not CCR1 and CCR3 expression. CCR5 mAb, inhibitor and siRNA reduced the CCL5-enhanced the migration and integrin up-regulation of osteosarcoma cells. Activations of MEK, ERK and NF-κB pathways after CCL5 treatment were demonstrated, and CCL5-induced expression of integrin and migration activity was inhibited by the specific inhibitor and mutant of MEK, ERK and NF-κB cascades. In addition, overexpression of CCL5 shRNA inhibited the migratory ability and integrin expression in osteosarcoma cells.Conclusions
These results suggest that the CCL5 and CCR5 interaction acts through the MEK/ERK signaling pathway, which in turn activates NF-κB, resulting in the activation of αvβ3 integrin and contributing the migration of human osteosarcoma cells.