Amino acids (AAs) are traditionally classified into nutritionally essential AAs (EAAs) or nonessential AAs (NEAAs) for animals and humans. Recent studies have demonstrated that not only EAAs but also NEAAs play important roles on energy metabolisms in cancer cells. However, which AAs are indispensable for human cancer cell survival has not been fully elucidated. The purposes of this study were 1) to determine the indispensable AAs for ovarian cancer (OVC) cells and 2) to investigate the relationship between the AAs synthetase and cancer cell survival.

Firstly, OVC cell lines were cultured with different medium in which each AA was depleted and cancer cell survival was examined. Among 17 OVC cell lines, EAAs were required in 12 cell lines, whereas others did not require EAAs for cell survival. Interestingly, cancer cell lines which required EAA also required at least one NEAAs, including arginine, cystine, glutamine, serine and tyrosine. Although extracellular glutamine has been known to be a critical factor for cancer cell survival and growth, 3 OVC cell lines did not require extracellular glutamine. Hence, we next examined glutamine synthetase (GS) gene, which is a critical enzyme for production of endogenous glutamine from glutamate. In OVC cell lines which did not require extracellular glutamine, GS expression level was positively correlated with cell survival rate under glutamine-depleted condition. Furthermore, we found that the expression of GS protein was negative in 38 of 645 primary OV tumors (5.9 %). Taken together, these results suggest that GS-down-regulated OVC cells require extracellular glutamine for their survival. Therefore, uptake inhibition of extracellular glutamine or reduction of extracellular glutamine level may be a novel therapeutic strategy for patients with ovarian cancer with “GS down-regulation”, as well as development of an AA-based precision medicine of OVC.

Citation Format: Akiko Furusawa, Jun Inoue, Hitoshi Tsuda, Naoyuki Miyasaka, Johji Inazawa. Differential requirement of amino acids on cell survival of ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2497. doi:10.1158/1538-7445.AM2017-2497