Abstract 2650: Inhibition of glucose uptake by targeting GLUT3 reduces cell invasion and metastasis of triple-negative breast cancer cells through modulating AMPK-mediated cell mechanics

Abstract Obesity is accompanied by dysregulated metabolic functions including hyperglycemia, hyperinsulinemia, and hypertriglyceridemia. In clinics, obesity has been associated with increased breast cancer metastasis. Since cancer cells are highly dependent on aerobic glycolysis, called the Warburg effect, we hypothesized that the elevated extracellular glucose level that cancer cells experience with hyperglycemia in obesity promotes cancer metastasis. The capacity of cancer cells to deform and exert contractile force, known as cell mechanics, plays a crucial role in various stages of metastasis. Our previous study demonstrated that elevated extracellular glucose levels boost glycolysis and activate the RhoA signaling pathway in human triple-negative breast cancer (TNBC) cells, resulting in heightened cell stiffness and increased contractility. Such modified cell mechanics are associated with enhanced cell migration and invasion, consistent with other in vitro studies showing that high extracellular glucose levels promote cancer cell motility. In the current study, we present our new findings indicating that inhibition of glucose transporter 3 (GLUT3) significantly diminishes the motility of TNBC cells, including human (MDA-MB-231) and mouse (EO771) TNBC cells. Mechanistic investigations reveal that inhibition of glucose uptake by targeting GLUT3 pharmacologically using GLUT3-selective inhibitor (G3iA) or genetically using GLUT3 knock-out cells reduces glucose uptake and glycolysis without affecting cell viability. Such reduced glycolysis activates 5' AMP-activated protein kinase (AMPK) and decreases total F-actin levels and non-muscle myosin II activity, which results in decreased cell stiffness. We further elucidated that the decreased F-actin level is mediated by actin regulators including VASP and cofilin. These changes are associated with a reduction in cell migration. To confirm the anti-metastatic effects of GLUT3 inhibition in vivo, we developed two obese-TNBC mouse models using diet-induced obesity (DIO) strategy in NSG mice and C57BL/6J mice with orthotopic implantation of human and mouse TNBC cells, respectively. GLUT3 deficient MDA-MB-231 cells showed significantly reduced lung metastasis compared to wild-type MDA-MB-231 cells. In summary, our results suggest that inhibiting GLUT3 modifies the mechanics of TNBC cells, leading to a decrease in cell motility and metastasis. Given that GLUT3 is notably elevated in TNBC and is linked to metastatic progression and a poor prognosis in breast cancer patients, our findings underscore the need for further in vivo studies to validate G3iA as a potential anti-metastatic drug in obese TNBC patients. Citation Format: Aadil Qadir Bhat, Seeun Oh, Cristina V. Iancu, Jun-yong Choe, Dongjoon Lee, Donghoon Yoon, Tae-Hyung Kim. Inhibition of glucose uptake by targeting GLUT3 reduces cell invasion and metastasis of triple-negative breast cancer cells through modulating AMPK-mediated cell mechanics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2650.