Glioblastoma Secrete Mcp-1, A Monocyte Chemotactic Factor

Immunohistological studies on glioblastoma tumor sections have demonstrated the presence of variable amounts of infiltrating macrophages. To understand how these macrophages are recruited from the circulation through the blood brain barrier, we have tested for the presence of macrophage chemotactic factors such as MCP-1. MCP-1 is a human monocyte chemoattractant protein produced by several cell types such as fibroblasts, PMA stimulated PBMC and human glioma cell-line U-105MG. We found various constitutive levels of different specific MCP-1 mRNAs in 10/13 cell lines. The inflammatory cytokines IL-lβ and TNFα could induce or increase the MCP-1 mRNA in all cell lines analyzed. To demonstrate in vivo MCP-1 production we showed that ex vivo extracted tumors contained MCP-1 mRNA, both in low and high grade astrocytomas. In situ hybridization is actually performed on glioblastoma tissue sections to determine the in vivo cellular origin of MCP-1.