Clin Transl Med. 2026 Sep;16(9):e70784. doi: 10.1002/ctm2.70784.

ABSTRACT

BACKGROUND: As a pivotal metabolic enzyme, cysteine dioxygenase type 1 (CDO1) exerts tumour-suppressive effects across diverse tumour types, and its expression is strongly correlated with clinical prognosis. However, the molecular mechanisms underlying CDO1-mediated tumour suppression in gastric cancer (GC), its relationship with the tumour-associated immune microenvironment, and pharmacological strategies to restore its expression remain poorly understood.

METHODS: CDO1 expression and prognosis were evaluated by multi-omics and tissue microarray analyses. Tumour microenvironment and immune infiltration were analyzed using ESTIMATE and ssGSEA. Downstream pathways and interacting proteins were identified by transcriptomics, co-immunoprecipitation, and GST pull-down. CDO1 function was assessed by proliferation, apoptosis, and migration assays in gain- and loss-of-function models. In vivo tumorigenesis and CDO1-dependent decitabine efficacy were evaluated by subcutaneous xenografts. Patient-derived organoids were used to assess decitabine sensitivity and 5-FU synergy.

RESULTS: Compared with normal controls, CDO1 expression was notably decreased in GC tissues, and its low expression was strongly linked to unfavourable prognosis, supporting its utility as a biomarker for prognosis. Elevated CDO1 levels correlated with an immune-active tumour microenvironment and reduced metastatic signatures. Mechanistically, CDO1 directly bound to PI3K p85α, disrupting p85α-p110α dimerization, thereby attenuating PI3K/AKT phosphorylation and downregulating THBS1 expression. CDO1 overexpression led to reduced proliferation, invasiveness, and EMT, accompanied by increased apoptosis. These effects were reversed by PI3K activation or THBS1 co-overexpression. Decitabine was identified as an agent that epigenetically restores CDO1 expression. Critically, CDO1 knockdown significantly attenuated the anti-tumour efficacy of decitabine in vivo, confirming that decitabine acts primarily through CDO1 reactivation. Decitabine synergized with 5-FU in both organoids and xenografts.

CONCLUSIONS: Our data identify CDO1 as both a biomarker for prognosis and a tumour suppressor in gastric cancer. They reveal a CDO1-PI3K/AKT-THBS1 signalling axis and support the epigenetic reactivation of CDO1 by decitabine as a translatable therapeutic strategy.

KEY POINTS: CDO1 is frequently downregulated in gastric cancer and serves as an independent favourable prognostic biomarker. CDO1 directly binds PI3K p85α, disrupting p85α-p110α dimerization to suppress the PI3K/AKT-THBS1 signalling axis. Decitabine epigenetically restores CDO1 expression, and its anti-tumour activity is critically CDO1-dependent in vivo. Combining decitabine with 5-FU synergistically overcomes gastric cancer growth in patient-derived organoids and subcutaneous xenograft models.

PMID:42670236 | PMC:PMC13527532 | DOI:10.1002/ctm2.70784

Anal Bioanal Chem. 2026 Jul 27. doi: 10.1007/s00216-026-06702-z. Online ahead of print.

ABSTRACT

Protein glycosylation is a major post-translational modification that regulates tumor initiation and progression; however, its dynamic modeling during multistep evolution of lung adenocarcinoma (LUAD) remains poorly understood, particularly in clinically archived tissues. Here, we established an integrated multi-omics workflow combining global proteomes, N-glycans, and site-specific intact N-glycopeptides to comprehensively characterize glycosylation in formalin-fixed paraffin-embedded (FFPE) specimens spanning four pathological stages of LUAD progression: inflammatory nodules (IN), atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), and invasive adenocarcinoma (IAC). Using optimized protein extraction, hydrophilic interaction liquid chromatography (HILIC)-based glycopeptide enrichment, and high-resolution LC-MS/MS, we achieved large-scale identification of proteins, N-glycans, and intact glycopeptides from archival clinical samples. Integrated analyses revealed progressive remodeling of site-specific N-glycosylation during malignant transformation, characterized by increased glycan branching, fucosylation, and sialylation during the transition from premalignant lesions to invasive cancer. Sialylated glycans reached their highest abundance in the premalignant AAH stage, whereas highly branched and fucosylated complex N-glycans predominated in invasive adenocarcinoma, indicating stage-dependent glycan remodeling throughout disease progression. Functional enrichment analyses linked these glycosylation alterations to extracellular matrix organization, neutrophil degranulation, and immune-associated pathways, while representative glycoproteins, including CEACAM6 and FGB, exhibited coordinated changes in protein abundance and site-specific glycoform micro-heterogeneity across pathological stages. Collectively, this study demonstrates the feasibility of deep glycoproteomic profiling using archived FFPE tissues and provides a comprehensive molecular atlas of glycosylation remodeling during LUAD progression. These findings establish a valuable resource for elucidating disease mechanisms and identifying stage-specific glycosylation biomarkers and potential glycan-targeted therapeutic candidates for early lung adenocarcinoma.

PMID:42509285 | DOI:10.1007/s00216-026-06702-z