Porphyromonas Gingivalis And Polarization Of Macrophages Promotes Tumor Progression In Oral Tumor Microenvironment

Objective:To investigate the relationship between P.gingivalis and two polarized phenotypes of TAMs with clinicopathological characteristics and prognosis in patients with OSCC.Methods:Part I:A retrospective study of 42 OSCC patients and surgical specimens admitted to the Department of Maxillofacial Oncology,The First Affiliated Stomatological Hospital of Xinjiang Medical University from 2014 to 2016,and the patients who were strictly followed up.Immunohistochemical staining was performed with the approval of the Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University.Immunohistochemical detection of P.gingivalis and dividing all specimens into two groups with high and low expression then detecting markers of M1 and M2 TAMs,respectively.t-test and Chi-square test were used for comparison between groups,and Spearman correlation analysis was used for correlation analysis,and the association between the degree of detection of each index and pathological features and their prognosis.The locations of expression of CD86~+,CD163~+,CD204~+,and CD206~+TAMs in OSCC tissues were determined.Part II:In vitro experiments to culture SCC7 murine-derived squamous carcinoma cell line and establish co-culture models.12 C57Balb/C mice were used to establish animal models,divided into control and experimental groups,and mice in the control group were injected with SCC-7 cell line culture suspension in the left buccal mucosa to form tumors,and the experimental group was injected with SCC7+P.gingivalis co-culture mixture suspension model tumorigenesis.After tumor formation,the mice were executed at the cut-off points of 10 and 20 days,respectively,and the tumor tissues were excised for the detection of M1 and M2 TAMs markers.The data were statistically analyzed using the statistical software SPSS 23.0,and the figures were expressed as the mean±standard deviation,and the differences were considered statistically significant at P<0.05.Images were analyzed and processed using Image J Pro plus software.Results:Part I:The data of the gross specimens showed that in 42 OSCC patients,P.gingivalis was highly expressed in 27 cases and P.gingivalis was lowly expressed in 15 specimens;there were statistical differences in the expression of CD86~+and CD206~+TAMs between the two groups(P>0.05);there were also differences in the distribution of M2-type TAMs in tumor tissues,namely CD163 was widely detected in the interstitial and peritumoral tumors,while CD204 and CD206 were mainly detected in and around the tumors;clinical staging showed a significant increase in the number of CD204~+and CD206~+cells;CD163~+,CD204~+and CD206~+cells were increased in OSCC patients with cervical lymph node metastasis;and CD163~+,CD204~+and CD206~+cells were detected in patients with hypodifferentiated OSCC.CD163~+cells were detected to a statistically different extent.(P<0.05).Part II:The volume change of mice in the experimental group was significantly larger and the maximum diameter was larger than that in the control group.In addition,the volume change was faster at the second time period than at the first time period.In addition,P.gingivalis was highly expressed in the experimental group and lowly expressed in the control group;the difference in the expression of antibody markers for M1 macrophages was not significant between the control and experimental groups;the difference in the expression of M2 cells was greater,in which CD206~+cells were expressed around the tumor and in the interstitium,especially around the blood vessels,and CD163~+M2 cells were diffusely expressed inside the tumor and in the interstitial tissue.CD204~+cells were expressed in the peritumor area.Conclusions:P.gingivalis is involved in the polarization of macrophages to the M2 subtype in the oral tumor microenvironment.