Abstract 3671: Targeting SLC2A1 and SLC38A2-mediated metabolic shift in SMARCA4/A2-dual deficient cancer

Abstract

SMARCA4 (BRG1) and SMARCA2 (BRM) are the two paralogous ATPases of the SWI/SNF chromatin remodelling complexes. These two ATPases are frequently inactivated in cancers and cancer cells deficient in either of them have been shown to depend on the remaining counterpart for survival. Contrary to this paralog synthetic lethality, concomitant loss of SMARCA4 and SMARCA2 occurs in a subset of cancers that are often associated with very poor patient outcomes. Here, we uncover that dual loss of SMARCA4/A2 represses the expression of SLC2A1, encoding the glucose transporter GLUT1, which results in reduced glucose uptake and glycolysis accompanied with increased dependency on oxidative phosphorylation (OXPHOS); adapting to this, these SMARCA4/A2-dual deficient cells rely on elevated SLC38A2, an amino acid transporter, to increase glutamine import for fueling OXPHOS. Consequently, SMARCA4/A2-dual deficient cells and tumours are highly sensitive to inhibitors targeting OXPHOS or glutamine metabolism. Furthermore, supplementation of alanine, also imported by SLC38A2, restricts glutamine uptake through competition and selectively induces death in SMARCA4/2-dual deficient cancer cells. At a clinically relevant dose, alanine supplementation synergizes with OXPHOS inhibition or conventional chemotherapy eliciting marked antitumor activities in SMARCA4/A2-dual deficient cancer cell lines and patient-derived xenografts. Our findings reveal multiple druggable vulnerabilities of SMARCA4/A2-dual loss exploiting a GLUT1/SLC38A2-mediated metabolic shift. Particularly, unlike dietary deprivation approaches, alanine supplementation can be readily applied to current regimens for better treatment of these aggressive cancers. * Authors contributed equally# Co-corresponding Citation Format: Xianbing Zhu, Zheng Fu, Shary Chen, Dionzie Ong, Giulio Aceto, Rebecca Ho, Jutta Steinberger, Eunice Li, David Huntsman, William Foulkes, Sidong Huang, Yemin Wang. Targeting SLC2A1 and SLC38A2-mediated metabolic shift in SMARCA4/A2-dual deficient cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3671.