Arrested neural and advanced mesenchymal differentiation of glioblastoma cells-comparative study with neural progenitors

Abstract

BackgroundAlthough features of variable differentiation in glioblastoma cell cultures have been reported, a comparative analysis of differentiation properties of normal neural GFAP positive progenitors, and those shown by glioblastoma cells, has not been performed.MethodsFollowing methods were used to compare glioblastoma cells and GFAP+NNP (NHA): exposure to neural differentiation medium, exposure to adipogenic and osteogenic medium, western blot analysis, immunocytochemistry, single cell assay, BrdU incorporation assay. To characterize glioblastoma cells EGFR amplification analysis, LOH/MSI analysis, and P53 nucleotide sequence analysis were performed.ResultsIn vitro differentiation of cancer cells derived from eight glioblastomas was compared with GFAP-positive normal neural progenitors (GFAP+NNP). Prior to exposure to differentiation medium, both types of cells showed similar multilineage phenotype (CD44+/MAP2+/GFAP+/Vimentin+/Beta III-tubulin+/Fibronectin+) and were positive for SOX-2 and Nestin. In contrast to GFAP+NNP, an efficient differentiation arrest was observed in all cell lines isolated from glioblastomas. Nevertheless, a subpopulation of cells isolated from four glioblastomas differentiated after serum-starvation with varying efficiency into derivatives indistinguishable from the neural derivatives of GFAP+NNP. Moreover, the cells derived from a majority of glioblastomas (7 out of 8), as well as GFAP+NNP, showed features of mesenchymal differentiation when exposed to medium with serum.ConclusionOur results showed that stable co-expression of multilineage markers by glioblastoma cells resulted from differentiation arrest. According to our data up to 95% of glioblastoma cells can present in vitro multilineage phenotype. The mesenchymal differentiation of glioblastoma cells is advanced and similar to mesenchymal differentiation of normal neural progenitors GFAP+NNP.

Association of loss of heterozygosity with shorter survival in primary glioblastoma patients

“…Multiplex PCR was performed for evaluation of EGFR amplification with superoxide dismutase 1 (SOD1) used as a reference gene as described previously [28].…”

Isolation of a new cell population in the glioblastoma microenvironment

“…EMT and mesenchymal-epithelial transition (MET) are key regulators of cellular plasticity in carcinomas and play a key role in treatment resistance, tumor recurrence, and metastatic progression [38]. Recent studies have shown that GBs have mesenchymal properties [39][40][41][42][43][44]. However, the normal CGH array profile of GASCs, contrasting with the abnormal profile of GB tumor cells, is not consistent with this hypothesis.…”

Tubulin targets in the pathobiology and therapy of glioblastoma multiforme. I. class III β‐tubulin

“…There is an increasing body of evidence indicating that astrocytic gliomas may be derived from intermediate gliotypic neural stem cells (Walton et al, 2009). Undifferentiated cancer cells derived from GBM and glial fibrillary acidic protein (GFAP)þ normal neural progenitors maintained in culture share a ''multilineage'' antigenic phenotype (CD44þ/microtubule associated protein-2þ/GFAPþ/vimentinþ/bIII-tubulinþ/fibronectinþ) (Rieske et al, 2009). It should be noted that, GFAPþ/nestinþ/ bIII-tubulinþ cells in GBMs resemble normal human fetal astrocytes in vitro (Rieske et al, 2007;Dráberová et al, 2008) and of glial precursor or neural stem cells of the human telencephalic subventricular zones (Dráberová et al, 2008) (Fig.…”