Previous studies have indicated pro-
tumor functions of macrophages in
tumor progression in different types of malignant
tumors. The detailed mechanisms of cell-cell interaction between macrophages and
tumor cells have been investigated by means of in vitro co-culture experiments. The present study developed magnetite nanoparticles modified with
gelatin that are specifically engulfed by macrophages and investigated methods to deplete these macrophages in co-culture experiments using a magnet. T98G
glioma cell line and human monocyte-derived macrophages were mixed and co-cultured for 2 days. The T98G cells were isolated by depletion of the macrophages using the magnetite nanoparticles.
mRNA expression of a number of pro-
tumor molecules in the isolated T98G cells, with or without co-culture with macrophages, was then evaluated. The
mRNA expression levels of
chemokine (CC motif)
ligand 2,
interleukin-6 and
macrophage-colony stimulating factor receptor (M-CSFR) were significantly upregulated in T98G cells by co-culture with macrophages (P<0.01). M-CSFR
protein expression was also increased by co-culture with macrophages. The
conditioned medium of co-cultured cells increased M-CSFR expression in T98G cells. Magnetite nanoparticles may be a novel tool not only for investigating the unique activation status of
tumor cells in co-culture conditions, but also for targeting pro-
tumor macrophages in
tumor tissues.