PPARδ Reprograms Glutamine Metabolism in Sorafenib-Resistant HCC

The tyrosine kinase inhibitor sorafenib is the only therapeutic agent approved for the treatment of advanced hepatocellular carcinoma (HCC), but acquired resistance to sorafenib is high. Here, we report metabolic reprogramming in sorafenib-resistant HCC and identify a regulatory molecule, peroxisome proliferator-activated receptor-delta (PPAR delta), as a potential therapeutic target. Sorafenib-resistant HCC cells showed markedly higher glutamine metabolism and reductive glutamine carboxylation, which was accompanied by increased glucose-derived pentose phosphate pathway and glutamine-derived lipid biosynthetic pathways and resistance to oxidative stress. These glutamine-dependent metabolic alterations were attributed to PPAR delta, which was upregulated in sorafenibresistant HCC cells and human HCC tissues. Furthermore, PPAR delta contributed to increased proliferative capacity and redox homeostasis in sorafenib-resistant HCC cells. Accordingly, inhibiting PPAR delta activity reversed compensatory metabolic reprogramming in sorafenib-resistant HCC cells and sensitized them to sorafenib. Therefore, targeting compensatory metabolic reprogramming of glutamine metabolism in sorafenib-resistant HCC by inhibiting PPAR delta constitutes a potential therapeutic strategy for overcoming sorafenib-resistance in HCC. (C) 2017 AACR.