Kees T, Lohr J, Noack J, Mora R, Gdynia G, Tödt G, Ernst A, Radlwimmer B, Falk CS, Herold-Mende C, Régnier-Vigouroux A. Microglia isolated from patients with glioma gain antitumor activities on poly (I:C) stimulation.
Neuro Oncol 2011;
14:64-78. [PMID:
22015597 DOI:
10.1093/neuonc/nor182]
[Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The role of microglia, the brain-resident macrophages, in glioma biology is still a matter of debate. Clinical observations and in vitro studies in the mouse model indicate that microglia and macrophages that infiltrate the brain tumor tissue in high numbers play a tumor-supportive role. Here, we provide evidence that human microglia isolated from brain tumors indeed support tumor cell growth, migration, and invasion. However, after stimulation with the Toll-like receptor 3 agonist poly (I:C), microglia secrete factors that exerted toxic and suppressive effects on different glioblastoma cell lines, as assessed in cytotoxicity, migration, and tumor cell spheroid invasion assays. Remarkably, these effects were tumor-specific because the microglial factors impaired neither growth nor viability of astrocytes and neurons. Culture supernatants of tumor cells inhibited the poly (I:C) induction of this microglial M1-like, oncotoxic profile. Microglia stimulation before coculture with tumor cells circumvented the tumor-mediated suppression, as demonstrated by the ability to kill and phagocytose glioma cells. Our results show, for the first time to our knowledge, that human microglia exert tumor-supporting functions that are overridden by tumor-suppressing activities gained after poly (I:C) stimulation.
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