Table 3_Multiomics profiling reveals that P. gingivalis-induced extracellular vesicle reprogramming promotes immune evasion in colorectal cancer through autophagy-mediated STING degradation.xlsx

ObjectivePorphyromonas 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.
MethodsAn 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.
ResultsP. 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.
ConclusionThis 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.

研究目的：牙龈卟啉单胞菌（Porphyromonas gingivalis，下称P. gingivalis）感染是结直肠癌（colorectal cancer，CRC）公认的致病因素，而细胞外囊泡（extracellular vesicles，EVs）是肿瘤微环境中的关键介导因子。然而，源自P. gingivalis感染癌细胞的大细胞外囊泡（large extracellular vesicles，lEVs）的分子组成仍未得到充分解析。本研究旨在全面解析结直肠癌细胞受P. gingivalis感染后分泌的大细胞外囊泡中的分子载荷改变。

研究方法：本研究采用整合多组学方法，分析P. gingivalis感染的HCT116结直肠癌细胞分泌的大细胞外囊泡。分别通过miRNA测序和定量蛋白质组学技术解析miRNA与蛋白质的表达谱。借助生物信息学分析筛选差异表达分子，并通过免疫印迹及自噬抑制实验开展机制研究，以验证并探索关键发现。

研究结果：P. gingivalis感染可显著重塑HCT116细胞来源的大细胞外囊泡的分子载荷。miRNA测序共鉴定出223种miRNA，其中28种存在差异表达，尤为值得注意的是，感染细胞来源的大细胞外囊泡中特异性上调了6种新型miRNA。定量蛋白质组学共鉴定出1210种表达显著改变的蛋白质，其中981种表达下调，包括关键的抗肿瘤免疫调控因子STING（stimulator of interferon genes，干扰素基因刺激因子）。研究证实，受感染的HCT116细胞中STING表达下调，且P. gingivalis感染可通过自噬途径促进STING降解，这解释了其在大细胞外囊泡中掺入量减少的原因。

研究结论：本项整合多组学分析表明，P. gingivalis感染可显著重塑结直肠癌细胞来源的大细胞外囊泡的分子特征。大细胞外囊泡中免疫刺激因子（尤其是STING）的特异性耗竭，提示该条件致病菌可通过一种全新机制参与P. gingivalis相关结直肠癌的免疫逃逸并促进肿瘤进展。