Involvement Of Glutamine In Tolerance Of Human Pancreatic Cancer Cell To Inhibition Of Fatty Acid Synthesis

Abstract Pancreatic cancer (PC) is the fifth leading cause of cancer-related mortality in Japan. Although the standard chemotherapy regimens, FOLFIRINOX (fluorouracil, leucovorin, irinotecan and oxaliplatin), gemcitabine and nab-paclitaxel, are widely used to treat patients with advanced pancreatic cancer, their antitumor effects (progression and survival rates) are less potent against this cancer type than other solid tumors. Previously, we found that inhibition of acetyl-CoA carboxylase (ACC), a major rate-controlling enzyme of fatty acid synthetic pathway, suppressed the proliferation of PC cells. However, in this study, we found the tolerance to the inhibition in a part of PC cells. Therefore, we investigated the mechanism of the tolerance to ACC inhibition in PC cells. The human PC cell lines, AsPC-1, BxPC-3 and PANC-1 were obtained from the American Type Culture Collection. Live and apoptotic cell numbers were determined using the MUSE Annexin V and Dead Cell Kit according to the manufacturer's instructions. PANC-1 cells showed the tolerance to inhibition of fatty acid synthesis by ACC inhibitor, 5-(tetradecyloxy)-2-furoic acid (TOFA), whereas TOFA induced apoptosis in AsPC-1 and BxPC-3 cells. In addition, PANC-1 did not show autophagy even under the condition of fatty acid starvation. Next, we investigated whether PANC-1 has the tolerance to nutrient starvation in nutrient-depletion medium, Earle's Balanced Salt Solution (EBSS) and serum-free medium respectively. PANC-1 showed the survival even in such mediums, whereas AsPC-1 and BxPC-3 almost dead. This result suggests that the tolerance of fatty acid starvation of PANC-1 are related to that of nutrient starvation. Interestingly, proliferation of PANC-1 cultured in glutamine-depletion medium dramatically was suppressed, even though low glucose medium did not affect. BPTES, a selective inhibitor of glutaminase, also suppressed the proliferation and induced apoptosis in PANC-1, whereas there are little effects of 2-dexy-glucose, inhibitor of glycolysis, on them. These results suggest that the TCA cycle plays an important role on the tolerance to inhibition of fatty acid synthesis and nutrient starvation of PANC-1, and can be novel therapeutic target of PC cells which have the tolerance to nutrient starvation like PANC-1. Citation Format: Koji Nishi, Mina Suzuki, Noriko Yamamoto, Yumiko Iwase, Nagahiko Yumita. Involvement of glutamine in tolerance of human pancreatic cancer cell to inhibition of fatty acid synthesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2323.