Abstract 3046: Glutamate dehydrogenase 1 signals through antioxidant glutathione peroxidase 1 to regulate redox homeostasis and tumor growth

Abstract

Abstract How mitochondrial glutaminolysis contributes to redox homeostasis in cancer cells remains unclear. Here we report that the mitochondrial enzyme glutamate dehydrogenase 1 (GDH1), commonly upregulated in human cancers, is predominantly important for redox homeostasis in cancer cells by controlling the intracellular levels of its product alpha-ketoglutarate (a-KG) and subsequent metabolite fumarate. Mechanistically, fumarate binds to and activates a ROS scavenging enzyme glutathione peroxidase 1 (GPx1) to regulate redox homeostasis, which provides a proliferative advantage to cancer cells and tumor growth. Our findings not only provide novel insights into understanding of the role of glutaminolysis in redox homeostasis but also suggest a novel signaling function of fumarate that regulates GPx1, allowing additional crosstalk between glutaminolysis, TCA cycle and redox status. Targeting GDH1 by shRNA or a newly identified small molecule inhibitor R162 resulted in imbalanced redox homeostasis, leading to attenuated cancer cell proliferation and tumor growth. Thus, our findings provide proof-of-principle suggesting GDH1 as a promising therapeutic target in the treatment of human cancers associated with elevated glutamine metabolism. Citation Format: Lingtao Jin, Dan Li, Gina Alesi, Jun Fan, Hee-Bum Kang, Lu Zhou, Titus Boggon, Kelly Magliocca, Chuan He, Martha Arellano, Hanna Khoury, Dong Shin, Fadlo Khuri, Sumin Kang. Glutamate dehydrogenase 1 signals through antioxidant glutathione peroxidase 1 to regulate redox homeostasis and tumor growth. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3046. doi:10.1158/1538-7445.AM2015-3046