Multiomics profiling reveals that P. gingivalis-induced extracellular vesicle reprogramming promotes immune evasion in colorectal cancer through autophagy-mediated STING degradation.

OBJECTIVE: Porphyromonas gingivalis (P. gingivalis) infection is a recognized pathogenic factor in colorectal cancer (CRC), and extracellular vesicles (EVs) are key mediators within the tumor microenvironment. However, the molecular composition of large extracellular vesicles (lEVs) derived from P. gingivalis-infected cancer cells remains poorly characterized. This study aimed to comprehensively define the molecular cargo alterations in lEVs secreted by CRC cells in response to P. gingivalis infection. METHODS: An integrated multiomics approach was employed to analyze lEVs secreted by P. gingivalis-infected HCT116 colorectal cancer cells. miRNA sequencing and quantitative proteomics were used to profile miRNA and protein expression, respectively. Bioinformatic analyses identified differentially expressed molecules. Mechanistic studies involving immunoblotting and autophagy inhibition were conducted to validate and explore key findings. RESULTS: P. gingivalis infection induced significant cargo remodeling in HCT116-derived lEVs. miRNA sequencing identified 223 miRNAs, among which 28 were differentially expressed. Notably, six novel miRNAs were specifically upregulated in lEVs from infected cells. Quantitative proteomics revealed 1,210 significantly altered proteins. Strikingly, 981 proteins were downregulated, including the critical antitumor immune regulator STING (stimulator of interferon genes). STING downregulation in infected HCT116 cells was confirmed, and P. gingivalis infection was shown to promote STING degradation via autophagy, explaining its reduced incorporation into lEVs. CONCLUSION: This integrated multiomics analysis demonstrates that P. gingivalis infection profoundly remodels the molecular landscape of CRC cell-derived lEVs. The specific depletion of immune-stimulating factors, most notably STING, within lEVs suggests a novel mechanism by which this pathobiont may contribute to immune evasion and promote tumor progression in P. gingivalis-associated colorectal cancer.