Screening Of Oral Mucosal Squamous Cell Carcinoma-related Microorganisms Based On Salivary Flora And Its Mechanism Of Invasion And Metastasis Of Oral Squamous Cell Carcinoma

Local invasion and distant metastasis are critical characteristics of high morbidity and poor prognosis in oral squamous cell carcinoma(OSCC),in which the specific oral microbiome promotes cancer progression by directly or indirectly affecting chronic inflammation.However,the mechanism by which the oral microbiome promotes cancer development remains largely unknown.Methods:16S rDNA sequencing was used to the abundance and composition in the saliva of participants.Fluorescence in situ hybridization was detected the location and abundance in OSCC tissues.CCK-8 assay and transwell invasion and migration assay were investigated the effect of Capnocytophaga gingivalis(C.gingivalis)on tumor proliferation,invasion and migration in vitro.The mechanisms underlying the effect of C.gingivalis were studied using quantitative real-time PCR and western blotting.Results:The overall microbiome abundance and composition were richer in the 108 controls than in the 70 OSCC cases.We demonstrated that Streptococcus,Capnocytophaga,Peptostreptococcus,Prevotella,and Lactobacillus were highly abundant in the saliva of OSCC patients.Moreover,we found that C.gingivalis was highly present in OSCC tissues.In vitro,we investigated that C.gingivalis induced cancer cells to undergo epithelial-to-mesenchymal transition(EMT),causing the cells to acquire a mesenchymal phenotype associated with highly invasive and metastatic properties.Conclusion : Our study reported that Streptococcus,Capnocytophaga,Peptostreptococcus,Prevotella,and Lactobacillus may the OSCC-related pathogenic bacteria and the new role for C.gingivalis relevant for cancer invasiveness and metastasis which may reveal new directions for the diagnosis or treatment of OSCC.