Valproic acid targets IDH1 mutants through alteration of lipid metabolism

Area of Science:

• Oncology
• Cancer Metabolism
• Epigenetics

Background:

• Histone deacetylases (HDACs) regulate chromatin and lipid metabolism in cancer.
• Valproic acid (VPA) is an anti-seizure drug and HDAC inhibitor with anti-cancer potential.
• IDH1 mutations are common in gliomas and influence tumor biology.

Purpose of the Study:

• To investigate the efficacy of VPA against IDH1 mutant gliomas.
• To explore the mechanisms by which VPA affects cancer cells, focusing on chromatin accessibility and lipid metabolism.
• To evaluate the therapeutic potential of targeting fatty acid metabolism in IDH1 mutant gliomas.

Main Methods:

• In vitro and in vivo studies using IDH1 mutant and wild-type glioma models.
• Chromatin accessibility assays (e.g., ATAC-seq).
• Gene expression analysis, Western blotting, lipidomic profiling, and apoptosis assays.
• Pharmacological inhibition and genetic knockdown of fatty acid synthase (FASN).
• Orthotopic xenograft mouse models for survival studies.

Main Results:

• VPA inhibited IDH1 mutant glioma growth in vitro and in vivo, with some selectivity over wild-type tumors.
• VPA downregulated lipogenic genes and decreased their promoter chromatin accessibility, particularly in IDH1 mutant cells.
• VPA inhibited the mTOR pathway and FASN, and both VPA and a FASN inhibitor induced lipidome changes and apoptosis in IDH1 mutant glioma cells.
• HDAC6 was identified as important for FASN regulation in IDH1 mutant gliomas.
• Combined VPA and FASN inhibition, or FASN knockdown alone, significantly improved survival in a mouse model.

Conclusions:

• HDAC inhibition by VPA targets fatty acid metabolism in IDH1 mutant gliomas.
• Targeting FASN, a key lipogenic gene regulated by HDACs, is a promising therapeutic strategy.
• Combined inhibition of HDACs and FASN represents a novel therapeutic opportunity for IDH1 mutant gliomas.