9-deoxy-delta-9-prostaglandin-d2 and Glioma

Malignant astrocytomas are among the most common brain tumours and few therapeutic options exist. It has recently been recognized that the ligand-activated nuclear receptor PPARgamma can regulate cellular proliferation and induce apoptosis in different malignant cells. We report the effect of three structurally different PPARgamma agonists inducing apoptosis in human (U87MG and A172) and rat (C6) glioma cells. The PPARgamma agonists ciglitazone, LY171 833 and prostaglandin-J2, but not the PPARalpha agonist WY14643, inhibited proliferation and induced cell death. PPARgamma agonist-induced cell death was characterized by DNA fragmentation and nuclear condensation, as well as inhibited by the synthetic receptor-antagonist bisphenol A diglycidyl ether (BADGE). In contrast, primary murine astrocytes were not affected by PPARgamma agonist treatment. The apoptotic death in the glioma cell lines treated with PPARgamma agonists was correlated with the transient up-regulation of Bax and Bad protein levels. Furthermore, inhibition of Bax expression by specific antisense oligonucleotides protected glioma cells against PPARgamma-mediated apoptosis, indicating an essential role of Bax in PPARgamma-induced apoptosis. However, PPARgamma agonists not only induced apoptosis but also caused redifferentiation as indicated by outgrowth of long processes and expression of the redifferentiation marker N-cadherin in response to PPARgamma agonists. Taken together, treatment of glioma cells with PPARgamma agonists may hold therapeutic potential for the treatment of gliomas.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; bcl-Associated Death Protein; Cadherins; Carrier Proteins; Cell Division; Cell Survival; DNA Fragmentation; Drug Evaluation, Preclinical; Glioma; Humans; Nuclear Proteins; Oligonucleotides, Antisense; Prostaglandin D2; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Pyrimidines; Rats; Receptors, Cytoplasmic and Nuclear; Thiazoles; Thiazolidinediones; Transcription Factors; Tumor Cells, Cultured

Cell kinetics of cancers have been described in books, texts and other reports, but the correlation with action mechanism of antineoplastic agents has rarely been mentioned in the literature. The action mechanism of the antineoplastic agents such as interferon, ACNU and cisplatin was analyzed with use of propidium iodide and BrdU double staining by flow cytometer. Interferon showed S phase accumulation, ACNU and cisplatin blocked the stage of G(2)M phase. Flow cytometry was useful for the analysis of cell kinetics.

Topics: Antineoplastic Agents; Brain Neoplasms; Cell Cycle; Cisplatin; Flow Cytometry; Glioma; Humans; Interferons; Nimustine; Prostaglandin D2; Tumor Cells, Cultured