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

Abstract

OBJECTIVES: Currently used glioblastoma cultures have many disadvantages and are being replaced by short-term cultures. However, these may include normal brain cells. BACKGROUND: A comparative model of normal and glioma cultures is lacking. A signifi cant contributory factor is because cultures from adult human brain contain small amounts of cells with glial phenotypes. The predominant population of fl at or spindle shaped cells does not express glial markers and are often termed as "glia-like". METHODS: Cryopreserved glioblastoma cultures from 28 bioptic samples were examined by immunofl uorescence using antibodies to intermediate fi laments (IF): glial fi brillary acidic protein (GFAP), cytokeratins (CK), nestin (Nes), vimentin (Vim) and neurofi laments (NF). RESULTS: 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. CONCLUSION: The presence of normal cells in short-term glioblastoma cultures may be caused by the infi ltrative 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). Text in PDF www.elis.sk.

Can permanent cell lines originate from low-grade astrocytomas: overgrowth of “glia-like“ cells in pilocytic and fibrillary (diffuse) astrocytoma cultures

“…These fi ndings match our observation. However, we explain the above-mentioned decrease in GFAPpositive cells by overgrowth with GFAP-negative "glia-like" cells, which in early passages may grow even more rapidly than glioma cells (6). Recently, we described the establishment of permanent glioblastoma cell lines in 2 of 30 cultures (12,15).…”

“…Similar cells with non-glial phenotypes were found in normal adult human brain cultures (9, 10). In addition, we recently demonstrated the presence of normal "glia-like" cells in glioblastoma cultures (6). Specifi c morphological features of astrocytic GFAP-positive and fl at GFAP-negative cells permit distinguishing between the neoplastic astrocytes and normal "glia-like" cells.…”

“…This term was introduced to cover the predominant population of GFAP-negative cells in brain cultures (5). Recently, we demonstrated the presence of "glia-like" cells in short-term glioblastoma cultures (6). Here, we characterize the cultures from low-grade astrocytomas occurring in adults and children.…”