Short-term glioblastoma cultures may contain normal "glia-like" cells

Currently used glioblastoma cultures have many disadvantages and are being replaced by short-term cultures. However, these may include normal brain cells.

A comparative model of normal and glioma cultures is lacking. A significant contributory factor is because cultures from adult human brain contain small amounts of cells with glial phenotypes. The predominant population of flat or spindle shaped cells does not express glial markers and are often termed as "glia-like".

Cryopreserved glioblastoma cultures from 28 bioptic samples were examined by immunofluorescence using antibodies to intermediate filaments (IF): glial fibrillary acidic protein (GFAP), cytokeratins (CK), nestin (Nes), vimentin (Vim) and neurofilaments (NF).

In short-term glioblastoma cultures GFAP-positive cells occured at higher percentages in 3/28 cultures and in lower percentages in further 5 cultures. Subpopulation of nestin positive cells were observed in all cultures and CK-positive cells were found in 25/28 cultures. All cells in all cultures were positively stained only for vimentin and negatively for NF. Cells grew slowly in 5 cultures which showed early proliferation arrest between passages 7 to 8. A further 23 cultures showed growth arrest by passages 10 to 15.

The presence of normal cells in short-term glioblastoma cultures may be caused by the infiltrative growth of these tumors. Our comparative analysis of morphological, growth and cytoskeletal properties revealed similarities between glioblastoma and normal brain cultures. In this study, the majority (28/30) of short-term glioblastoma showed limited life spans, similar to normal cells lacking spontaneous immortalization. The use of short-term glioblastoma cultures has two main problematic areas: cultures may contain a major subpopulation of normal "glia-like" cells; or they may contain the inital phases of spontaneously immortalized glioblastoma cells bearing properties of permanent cell lines (Tab. 1, Fig. 2, Ref. 19).