Biomolecular characterization of human glioblastoma cells in primary cultures: differentiating and antiangiogenic effects of natural and synthetic PPARgamma agonists

Gliomas are the most commonly diagnosed malignant brain primary tumors. Prognosis of patients with high-grade gliomas is poor and scarcely affected by radiotherapy and chemotherapy. Several studies have reported antiproliferative and/or differentiating activities of some lipophylic molecules on glioblastoma cells. Some of these activities in cell signaling are mediated by a class of transcriptional factors referred to as peroxisome proliferator-activated receptors (PPARs). PPARgamma has been identified in transformed neural cells of human origin and it has been demonstrated that PPARgamma agonists decrease cell proliferation, stimulate apoptosis and induce morphological changes and expression of markers typical of a more differentiated phenotype in glioblastoma and astrocytoma cell lines. These findings arise from studies mainly performed on long-term cultured transformed cell lines. Such experimental models do not exactly reproduce the in vivo environment since long-term culture often results in the accumulation of further molecular alterations in the cells. To be as close as possible to the in vivo condition, in the present work we investigated the effects of PPARgamma natural and synthetic ligands on the biomolecular features of primary cultures of human glioblastoma cells derived from surgical specimens. We provide evidence that PPARgamma agonists may interfere with glioblastoma growth and malignancy and might be taken in account as novel antitumoral drugs.