USP20-RAB8A signaling axis restricts pancreatic cancer progression by disrupting GLUT1 vesicular trafficking and inhibiting glucose uptake.

Cancer cells undergo metabolic reprogramming to meet the demands of rapid proliferation, survival and chemotherapy resistance. Targeting cancer-specific metabolic vulnerabilities offers a compelling strategy for therapeutic intervention. Owing to the Warburg effect and the unique tumor microenvironment, pancreatic ductal adenocarcinoma (PDAC) cells exhibit a high demand for glucose to sustain their energy metabolism. Here, we identify a novel regulatory mechanism controlling the cell surface abundance of glucose transporter 1 (GLUT1), mediated by RAB8A-dependent vesicular trafficking. RAB8A, a member of the RAS oncogene family, enhances GLUT1 membrane localization and thereby increases glucose uptake in PDAC cells. Mechanistically, we demonstrate that ubiquitin-specific peptidase 20 (USP20) negatively regulates RAB8A activation by selectively removing K48-linked polyubiquitin chains from its inactive form. Functional assays in vitro and in vivo validate the tumor-suppressive role of the USP20-RAB8A signaling axis. Furthermore, using primary PDAC cells derived from KPC (KrasG12D/+; Trp53 R172Hflox/flox; Pdx1-Cre) mice, we show that dual knockdown of Rab8a and Glut1 markedly attenuates tumor-promoting effects driven by oncogenic Kras and Trp53 loss. Collectively, our findings reveal that the USP20-RAB8A-GLUT1 axis regulates glucose uptake and metabolic reprogramming in PDAC, thereby inhibiting tumor growth and metastasis. Targeting this signaling axis provides a novel insight into metabolic therapy for pancreatic cancer.