Towards the Development of a 3D All Human In Vitro Model of Glioblastoma Multiforme for Drug Screening: Glioblastoma and Microglia Interactions?

Abstract: Glioblastoma multiforme (GBM) is a malignant brain tumour with poor prognosis (14.5 months) due to the propensity of GBM cells to diffusely invade the normal brain, the cell heterogeneity within the tumour, and the poor permeability of drugs across the blood-brain barrier. In addition to these factors, the tumour cells have also been shown to communicate with non-neoplastic cells (astrocytes and microglia), which can influence tumour metabolism and the response of tumour cells to therapeutic agents. Aiming to engineer an in vitro all human multicellular 3D model to mimic GBM, we investigated the effect of microglia cells in the response of GBM to cytotoxic agents. Three human GBM cell lines (U-87 MG, SNB-19 and UP-007) were cultured in human serum and used to evaluate the cytotoxicity of temozolomide, clomipramine and vincristine in a mono- and co-culture of the GBM cells with human microglia cells (CHME-3). For the co-cultures, cell labelling was optimised using CellTrace Cell Proliferation Kits (CFSE, carboxyfluorescein succinimidyl ester, or Far Red). GBM and CHME-3 cells were labelled with CellTrace CFSE and Far Red, respectively. The labelling of GBM and microglia cells allowed the assessment of the effect of the cytotoxic drugs in GBM cell populations when co-cultured with different amounts of microglia cells (such as, 10, 20 and 50%) either in a 2D (monolayer) or 3D environment (GrowDex hydrogel). Our preliminary study evaluated the role of microglia in the response of GBM cells to cytotoxic drugs establishing the basis for the development of a multicellular in vitro model of GBM.