CXCL8 promotes the invasion of human osteosarcoma cells by regulation of PI3K/Akt signaling pathway

Chemokine cysteine-X-cysteine motif ligand 8 (CXCL8) is up-regulated in many malignancies, indicating that CXCL8 takes part in tumor progression. However, the expression and function of CXCL8 in osteosarcoma remained not fully elucidated. In this study, expressions of 12 cytokines and chemokines were measured in the serum from 12 of normal controls (NCs) and 25 of osteosarcoma patients. The human osteosarcoma cell line MG-63 was stimulated by recombinant CXCL8 to further analyze invasion, proliferation, apoptosis, cell cycles, cytokine secretions, and signaling pathways. We found that serum concentrations of CXCL8 and vascular endothelial growth factor were elevated in osteosarcoma patients in comparison with those in NCs. CXCL8 stimulation led to enhancement of invasion and suppression of late stage apoptosis in MG-63 cells. Moreover, secretions of MMPs by MG-63 cells were also increased upon stimulation. However, early stage apoptosis, proliferation, and cell cycles were not affected by CXCL8 treatment. Furthermore, CXCL8 stimulation induced elevations of phosphorylated PI3K and Akt, but not PKC or FAK. In conclusion, our findings suggested that CXCL8 enhanced the invasion and suppressed late stage apoptosis of osteosarcoma cells probably via influencing PI3K/Akt signaling pathway and elevating the expression of MMPs. CXCL8 may promote disease progression of osteosarcoma as a protumorigenic molecule, and may be served as a new therapeutic target for osteosarcoma.