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Updated: Jul 4, 2026
Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion
Published on: October 20, 2016
Possible involvement of the M2 anti-inflammatory macrophage phenotype in growth of human gliomas
Y Komohara1, K Ohnishi, J Kuratsu
1Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Abstract:
Within tumours, many non-neoplastic cells such as fibroblasts, endothelial cells, and macrophages assist tumour growth by producing various growth factors and pro-angiogenic cytokines. Various tumour-derived molecules drive tumour-associated macrophages towards an anti-inflammatory phenotype (M2) and thus promoting tumour growth. Here we investigated microglia/macrophage differentiation in glioma tissues by means of immunostaining of paraffin-embedded glioma samples. The number of microglia/macrophages with positive staining for CD163 and CD204, which are believed to be markers for M2 macrophages, was correlated with the histological grade of the gliomas. The ratio of M2 macrophages in the tumour-associated microglia/macrophages was also associated with the histological grade. Culture supernatant from the glioma cell line can stimulate macrophages to develop into the M2 phenotype in vitro. Macrophage colony-stimulating factor (M-CSF), which strongly induces M2 polarization of macrophages, was significantly correlated with histological malignancy and with the proportion of M2 microglia/macrophages in vivo. In addition, the proportion of M2 microglia/macrophages and M-CSF expression in tumour cells correlated well with proliferation of glioblastoma cells. These results suggest that tumour-derived M-CSF induces a shift of microglia/macrophages towards the M2 phenotype, which influences tumour growth. Evaluation of the proportion of M2 microglia/macrophages and M-CSF expression in tumour tissue would be useful for assessment of microglia/macrophage proliferative activity and the prognosis of patients with gliomas.
Insights
Tumor-derived Macrophage Colony-Stimulating Factor (M-CSF) drives microglia/macrophages toward an M2 phenotype, promoting glioma growth. Evaluating M2 microglia/macrophages and M-CSF levels may predict patient prognosis.
Area of Science:
- Oncology
- Immunology
- Cell Biology
Background:
- Non-neoplastic cells, including macrophages, support tumor growth through secreted factors.
- Tumor-derived molecules can polarize macrophages to an M2 anti-inflammatory phenotype, fostering tumor progression.
- Microglia and macrophages are key immune components within the tumor microenvironment.
Purpose of the Study:
- To investigate microglia/macrophage differentiation in glioma tissues.
- To determine the correlation between M2 macrophage markers and glioma histological grade.
- To elucidate the role of Macrophage Colony-Stimulating Factor (M-CSF) in M2 polarization and glioma proliferation.
Main Methods:
- Immunohistochemical staining of paraffin-embedded glioma samples for M2 markers (CD163, CD204).
- Correlation analysis between M2 macrophage markers, histological grade, and M-CSF expression.
- In vitro experiments using glioma cell line supernatant to assess macrophage polarization.
- In vivo assessment of M-CSF expression in tumor cells and its relation to M2 microglia/macrophages.
Main Results:
- The number and ratio of M2 microglia/macrophages (CD163+, CD204+) positively correlated with higher glioma histological grades.
- Glioma cell line supernatant induced M2 polarization of macrophages in vitro.
- Tumor M-CSF expression significantly correlated with histological malignancy and the proportion of M2 microglia/macrophages.
- M2 microglia/macrophage proportion and M-CSF expression were linked to glioblastoma cell proliferation.
Conclusions:
- Tumor-derived M-CSF induces microglia/macrophage polarization to the M2 phenotype, contributing to glioma growth.
- The M2 phenotype of microglia/macrophages plays a significant role in glioma progression.
- Quantifying M2 microglia/macrophages and M-CSF in tumors could aid in assessing proliferative activity and patient prognosis for gliomas.
