Abstract 307: GPR120/FFAR4 activation by fatty acid 16:4(n-3) plays a key role in resistance to chemotherapy

Although chemotherapy is designed to eradicate tumor cells it also has a significant impact on normal tissues. These host-responses can have large effects on the efficacy of treatment and overall survival. Fatty acids are increasingly recognized to play important signaling roles. 12-S-HHT and 16:4(n-3) are two platinum-induced fatty acids (PIFAs) that induce systemic resistance to a broad range of DNA-damaging chemotherapeutics. PIFAs exert their chemoprotective effect on tumor cells via an indirect mechanism involving splenic F4/80 + /CD11b low macrophages. Here we identified GPR120 on mouse and human splenic macrophages as the relevant receptor for 16:4(n-3). GPR120 (FFAR4) is a free fatty acid receptor that binds medium- to long-chain fatty acids and omega-3 fatty acids and is involved in anti-inflammatory response and metabolic control. Although both GPR40 (FFAR1) and GPR120 can be activated by 16:4(n-3) in vitro, only inhibition or genetic loss of GPR120 was able to block 16:4(n-3)-mediated chemoresistance in vivo. Activation of the 16:4(n-3)-GPR120 axis led to enhanced cPLA 2 activity in splenic macrophages resulting in the production and secretion of resistance-inducing lysophosphatidylcholine 24:1 (LPC(24:1)). Taken together, we identified a novel function for GPR120. Activation by 16:4(n-3) leads to enhanced cPLA 2 activity and production of LPC(24:1) resulting in chemotherapy resistance. Citation Format: Julia Houthuijzen, Ilse Oosterom, Brian Hudson, Akira Hirasawa, Laura Daenen, Chelsea McLean, Steffen Hansen, Marijn van Jaarsveld, Daniel Peeper, sahar Jafari Sadatmand, Jeanine Roodhart, Chris van de Lest, Trond Ulven, Kenji Ishihara, Graeme Milligan, Emile Voest. GPR120/FFAR4 activation by fatty acid 16:4(n-3) plays a key role in resistance to chemotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 307.