Nuclear Protein C23 on the Cell Surface Plays an Important Role in Activation of CXCR4 Signaling in Glioblastoma

The chemokine receptor CXCR4 and its ligand stromal cell-derived factor 1 (SDF-1) plays an important role in tumor progression and are associated with angiogenesis. Meanwhile, the implications of C23 in multiple signaling pathways have been also investigated. However, the effects of C23 on CXCR4 pathway in glioblastoma are not fully characterized. In the present study, C23 and CXCR4 of U87 cell line were inhibited by anti-C23 and anti-CXCR4 antibodies, respectively; and then C23 and CXCR4 siRNAs were used to knock down endogenous C23 and CXCR4, respectively. In addition, MTT assay was also introduced. Our data showed that either anti-C23 or anti-CXCR4 antibodies efficaciously repressed the phosphorylation levels of ERK (p