Cell surface topography differs in the human “glia-like” and glioma cultures

Glioblastoma multiforme is the most malignant and incurable primary brain tumor. Infiltrative growth of gliomas into surrounding brain tissue may cause the presence of normal cells in glioma cultures. The aim of this study is to develop a simple, rapid method for detecting normal cells in short-term glioma cultures, to be applied primarily to personalized glioma treatment. Cell lines with permanent cell growth consist solely of cancer cells. Here, we examined two glioblastoma cell lines (8-MG-BA and 170-MG-BA), one brain metastatic carcinoma cell line (135-BCA), five short-term glioblastomas, and five human "glia-like" cultures using scanning electron microscopy (SEM), standard phase contrast microscopy, and GFAP immunofluorescence. All cells in glioblastoma and carcinoma cell lines were covered with microvilli of varying density, 4/5 of short-term glioblastoma cultures contained 1-3% cells with sparse microvilli, and one culture (139-GBM) showed microvilli in 15-20% of the cells and a higher percentage of GFAP-positive cells. A rare occurrence (less than 1%) of cells bearing microvilli was observed in all "glia-like" cultures. Using SEM, we observed similar cells with microvilli in both glioblastoma cell lines, but in the 135-BCA line, the microvilli were significantly shorter. Microvilli rarely occurred on normal "glia-like" cells. Based on this observation, we conclude that our 4/5 of short-term glioblastoma cultures contain predominantly normal "glia-like" cells. SEM could be a valuable method for distinguishing normal and tumor cells in short-term glioblastoma cultures, which have similar morphologies at light microscopy and immunophenotypes. We conclude that microvilli are characteristic of a specific tumor cell surface topography compared to "glia-like" cells.