Apoptosis ; Ascorbic Acid/pharmacology* ; Brain Neoplasms ; Cell Line, Tumor ; Glioma ; Humans ; Temozolomide/pharmacology*

In gliomas, the canonical Wingless/Int (WNT)/β-catenin pathway is increased while peroxisome proliferator-activated receptor gamma (PPAR-γ) is downregulated. The two systems act in an opposite manner. This review focuses on the interplay between WNT/β-catenin signaling and PPAR-γ and their metabolic implications as potential therapeutic target in gliomas. Activation of the WNT/β-catenin pathway stimulates the transcription of genes involved in proliferation, invasion, nucleotide synthesis, tumor growth, and angiogenesis. Activation of PPAR-γ agonists inhibits various signaling pathways such as the JAK/STAT, WNT/β-catenin, and PI3K/Akt pathways, which reduces tumor growth, cell proliferation, cell invasiveness, and angiogenesis. Nonsteroidal anti-inflammatory drugs, curcumin, antipsychotic drugs, adiponectin, and sulforaphane downregulate the WNT/β-catenin pathway through the upregulation of PPAR-γ and thus appear to provide an interesting therapeutic approach for gliomas. Temozolomide (TMZ) is an antiangiogenic agent. The downstream action of this opposite interplay may explain the TMZ-resistance often reported in gliomas.
Animals ; Brain Neoplasms ; metabolism ; therapy ; Dacarbazine ; analogs & derivatives ; pharmacology ; Down-Regulation ; drug effects ; Glioma ; metabolism ; therapy ; Humans ; PPAR gamma ; metabolism ; Temozolomide ; Wnt Signaling Pathway ; drug effects ; physiology

OBJECTIVE: To establish a mouse model bearing orthotopic temozolomide (TMZ)-resistant glioma that mimics the development of drug resistance in gliomas METHODS: Seventy-eight adult C57BL/6 mice were randomly divided into 6 groups ( RESULTS: The mouse models bearing TMZresistant glioma was successfully established. The cells from the high-dose induced group showed a significantly higher colony-forming rate than those from the high-dose control group ( CONCLUSIONS Progressive increase of TMZ doses in mice bearing orthotopic gliomas can effectively induce TMZ resistance of the gliomas.
Animals ; Antineoplastic Agents, Alkylating/pharmacology* ; Brain Neoplasms/drug therapy* ; Cell Line, Tumor ; Disease Models, Animal ; Drug Resistance, Neoplasm ; Glioma/drug therapy* ; Mice ; Mice, Inbred C57BL ; Temozolomide/therapeutic use*