Targeting the ANXA8-SP1-PPA1 Axis to Modulate TCA Cycle and Matrix Deposition in Diffuse-Type Gastric Cancer.

Abstract

Diffuse-type gastric cancer (DGC) is an aggressive tumor type characterized by a dense extracellular matrix (ECM). Metabolic reprogramming, a key oncogenic factor driving tumor progression, is closely linked to ECM deposition, although the regulatory mechanisms remain poorly understood. In this study, we integrated single-cell sequencing, proteomics, metabolomics, and large-scale clinical data to identify the metabolic signature of DGC. We found that the tricarboxylic acid (TCA) cycle is suppressed in DGC, which correlates with the formation of a dense ECM. Annexin A8 (ANXA8) was identified as a critical regulator that inhibits the TCA cycle in DGC and is positively associated with matrix formation. Mechanistically, ANXA8 interacts with SP1 to promote the transcription of pyrophosphatase 1, thereby suppressing the TCA cycle, activating cancer-associated fibroblasts, and facilitating aberrant ECM deposition. Deletion of ANXA8 suppresses malignant phenotypes and shows synergistic effects with the chemotherapeutic agent 5-fluorouracil (5-FU). Large-scale clinical data further confirmed the correlation between ANXA8 expression and both gastric cancer progression and 5-FU therapeutic efficacy. High-throughput organoid screening identified UNC2025 as a selective ANXA8 inhibitor. Targeting ANXA8 with UNC2025 restores TCA cycle activity and inhibits ECM deposition in DGC, enhancing the therapeutic effects of 5-FU in patient-derived xenografts and organoids. Furthermore, a polyphenol-based UNC2025 nanodelivery system improved the efficacy of this combination therapy. In summary, this study elucidates how ANXA8-mediated suppression of the TCA cycle promotes dense ECM formation and malignant progression in DGC, highlighting the therapeutic potential of targeting ANXA8 in DGC treatment.