ME-01 * GLIOMA CELL ADHESION AND INVASION REGULATED BY PROINFLAMMATORY CYTOKINE IN A NOVEL SURFACE/MATRIX CULTURE SYSTEM

Abstract

Brain tumors are complex integrated tissues containing microglia and tumor associated macrophages in addition to glioma cells and vascular elements. These monocyte-lineage cells make important contributions to the tumor microenvironment. Activated M1-polarized microglia secrete a number of proinflammatory cytokines including tumor necrosis factor (TNF). We have previously reported that TNF increases surfaced expression of the adhesion molecule VCAM-1 [Mahadev et al. (2014) PLoSOne 9:e95123; PMID:24787244], and expression profiling indicates an increase in markers of mesenchymal phenotype. We have extended these observations to examine glioma cell adhesion and invasion in a novel 2.5D culture system. In brain, one route of brain tumor dissemination from an already-formed mass is along blood vessels in their associated extracellular matrix (ECM). We have recapitulated this arrangement by initiating tumor cell cultures by placing 10 µl drops of 500-10,000 patient-derived brain tumor cells in stem cell medium supplemented with 3% Matrigel in the centers of 12-mm diameter glass coverslips, allowing them to adhere, and then flooding the well with 1 ml of the same culture solution. Addition of TNF (2.5-20 ng/ml) increased surface expression of VCAM-1 and CD44, and enhanced formation of fascicles resembling chain migration of neural progenitor, and of subsidiary tumor islands. These processes are reminiscent of tumor cell invasion in vivo. These studies will be extended to include activated monocyte-lineage cells and other cell types in vitro, and subsequently into in vivo xenograft models.