Abstract 374: Hypoxia-induced mitochondrial glutathione transporter expression causes drug resistance in colorectal cancer

Abstract Colorectal cancer (CRC) is the third most common type of cancer worldwide, with higher incidence and mortality rates. In order to adapt stress conditions during cancer progression, the cancer cells will be subject to metabolism reprogramming to increase energy production and remove hazardous substances. One of the important organelles, mitochondria is responsible for cellular ATP production, ion homeostasis, and several metabolic pathways. Therefore, mitochondria require a series of transporters called solute carrier family 25 (SLC25) to transport metabolites crossing the mitochondrial inner membrane, and dysregulation of those transporters causes abnormal cell morphology and diseases. In this study, members of the SLC25 family were analyzed in CRC via bioinformatics analysis, and a mitochondrial glutathione transporter was identified to overexpress in several public datasets of CRC and our own clinical specimens. In addition, its role has not been reported in any disease, including cancer. To systemically analyze the underlying mechanism causing overexpression of glutathione transporter during CRC progression, several stress conditions had been applied to colon cancer cells. However, only hypoxia was identified to induce its protein expression but not mRNA expression. Since a previous study reported that glutathione deprivation induced its protein expression, hypoxia didn’t alter the abundance of glutathione level suggesting that another glutathione-independent regulatory mechanism might be involve it. Interestingly, our findings revealed that hypoxia-induced glutathione transporter protein expression was mediated through the activation of internal ribosome binding site-mediated translation under hypoxia. To identify the potential role of glutathione transporter during colon cancer progression, its mitochondrial metabolite profiles from knockout cells of previous studies were further analyzed and identified that the changes of metabolites were associated with the urea cycle which had been reported to be associated with the sensitivity of oxaliplatin and 5-fluorouracil (5-FU) in cancer treatment. Importantly, our results showed that hypoxia-attenuated those chemotherapeutic effects were abolished by loss of glutathione transporter in colon cancer cells, indicating its crucial role in hypoxia-induced drug resistance. In conclusion, our study shows that glutathione transporter increased by hypoxia might lead to drug resistance of cancer therapy in colon cancer. Citation Format: Chin-Chun Lin. Hypoxia-induced mitochondrial glutathione transporter expression causes drug resistance in colorectal cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 374.