TBC1D23 drives lymphatic metastasis in pancreatic ductal adenocarcinoma by altering EGFR cell surface dynamics and signaling

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is among the most devastating malignancies worldwide, characterized by late diagnosis, rapid progression, and dismal survival rates. The discovery of reliable biomarkers for early detection and disease monitoring remains an urgent clinical need. Owing to its proximity to tumor cells and protein-rich composition, pancreatic juice represents a compelling reservoir for biomarker discovery. METHODS: We performed comprehensive proteomic profiling of pancreatic juice using mass spectrometry to uncover PDAC-associated biomarkers. The expression and prognostic relevance of candidate proteins were validated in patient-derived tumor tissues, sera, and tissue microarrays (TMAs). Functional roles were interrogated through RNA interference-mediated knockdown in PDAC cell lines and an orthotopic PANC-1 xenograft model. RESULTS: Our analyses revealed TBC1D23 as a previously unrecognized oncogenic driver in PDAC. TBC1D23 was markedly upregulated in pancreatic juice, tumor specimens, and patient sera, with elevated expression correlating strongly with lymphatic metastasis and inferior overall survival. Functionally, silencing TBC1D23 curtailed PDAC cell proliferation, migration, and invasion in vitro, and significantly attenuated tumor growth and peritoneal dissemination in vivo. Transcriptomic and biochemical analyses demonstrated that TBC1D23 depletion led to profound downregulation of VEGF-C, diminishing its secretion, and consequently impairing tumor-driven lymphangiogenesis. This effect was rescued by VEGF-C supplementation and abolished by the VEGFR3 inhibitor MAZ51, underscoring VEGF-C as a principal downstream effector. Mechanistically, TBC1D23 orchestrated EGFR trafficking, enhancing receptor recycling and membrane localization while suppressing lysosomal degradation, thereby sustaining EGFR/ERK signaling and driving VEGF-C upregulation. CONCLUSIONS: These findings uncover TBC1D23 as a novel regulator of EGFR dynamics and a pivotal mediator of PDAC lymphatic metastasis. By delineating the TBC1D23/EGFR/VEGF-C signaling axis, this study not only identifies a promising biomarker for PDAC detection and prognosis but also highlights an actionable therapeutic target for intercepting metastatic progression.