Abstract: Objective    To study the effect of CXC chemokine ligand 2（CXCL2）on epithelial mesenchymal transition（EMT）of oral squamous cell carcinoma（OSCC）cells infected by Porphyromonas gingivalis（P. gingivalis）. Methods    Totally 60 paraffin specimens of cancer and paracancerous tissues of OSCC patients treated in Stomatological Hospital of Xi′an Jiaotong University from June 2018 to May 2022 were divided into OSCC group and paracancerous group respectively，and the expressions of CXCL2，P.gingivalis and EMT related markers（vimentin and E-cadherin）were observed by immunohistochemical staining. Human tongue squamous cell carcinoma cell line TSCCA was used for cell experiment. Confocal laser scanning microscope and real-time fluorescence quantitative PCR（qRT-PCR）were used to identify the co-culture of TSCCA cells with P. gingivalis. The qRT-PCR was used to detect and compare the expression of EMT-related markers in TSCCA group（cultured TSCCA cells only），TSCCA+P. gingivalis group（co-culture of TSCCA cells with P. gingivalis）and TSCCA+P. gingivalis+CXCL2 group（co-cultured model with CXCL2）. CCK-8 assay and Transwell invasion assay were used to detect the proliferation and invasion ability of TSCCA cells in each group. Results    The positive expression rate of CXCL2，P. gingivalis and vimentin in OSCC group was significantly higher than that in paracancerous group，while the positive expression rate of E-cadherin was significantly lower than that in paracancerous group（P < 0.05）. Co-culture of TSCCA cells with P. gingivalis was successful. Compared with TSCCA group，the morphology of TSCCA cells in TSCCA+P. gingivalis group and TSCCA+P. gingivalis+CXCL2 group had interstitial-like changes，and the optical density（OD600），the number of invasive cells and the relative expression of mRNA of vimentin increased，while the relative expression of mRNA of E-cadherin decreased after 24 h and 48 h culture，and the changes in TSCCA+P. gingivalis+CXCL2 group were more obvious than those in TSCCA+P.gingivalis group，the difference being statistically significant（P < 0.05）. Conclusion    In the inflammatory microenvironment where P.gingivalis infects OSCC cells，CXCL2 may enhance the proliferation and invasion of tumor cells through the action of EMT.

Key words: CXC chemokine ligand 2, Porphyromonas gingivalis, oral squamous cell carcinoma, epithelial-mesenchymal transition

摘要： 目的    研究CXC趋化因子配体2（CXC chemokine ligand 2，CXCL2）对牙龈卟啉单胞菌（Porphyromonas gingivalis，P. gingivalis）感染的口腔鳞癌（oral squamous cell carcinoma，OSCC）细胞上皮间质转化（epithelial-mesenchymal transition，EMT）的影响。方法    选取2018年6月至2022年5月于西安交通大学口腔医院就诊的60例OSCC患者手术切除的癌及癌旁组织石蜡块标本，分别记为OSCC组和癌旁组；采用免疫组化染色方法观察2组CXCL2、P. gingivalis及EMT相关标志物［波形蛋白（vimentin）、E-钙黏蛋白（E-cadherin）］的表达情况。采用人舌鳞癌细胞系TSCCA进行细胞实验，应用共聚焦激光扫描显微镜和实时荧光定量PCR（qRT-PCR）鉴定TSCCA细胞与P. gingivalis共培养情况，采用qRT-PCR检测比较TSCCA组（单纯培养TSCCA细胞）、TSCCA+P. gingivalis组（TSCCA细胞与P. gingivalis共培养）和TSCCA+P. gingivalis+CXCL2组（共培养模型中加入CXCL2）中EMT相关标志物表达情况，采用CCK-8实验及Transwell侵袭实验检测各组TSCCA细胞增殖及侵袭能力。结果    OSCC组CXCL2、P. gingivalis和vimentin的表达阳性占比明显高于癌旁组，而E-cadherin的表达阳性占比明显低于癌旁组，差异均有统计学意义（P < 0.05）。TSCCA细胞与P. gingivalis共培养成功。与TSCCA组相比，TSCCA+P. gingivalis组和TSCCA+P. gingivalis+CXCL2组的TSCCA细胞形态发生间质样改变，细胞培养24、48 h后的光密度值（OD600值）、侵袭细胞数和vimentin的mRNA相对表达量升高，E-cadherin的mRNA相对表达量下降；且TSCCA+P. gingivalis+CXCL2组相较于TSCCA+P. gingivalis组以上改变更明显，差异均有统计学意义（均P < 0.05）。结论    P. gingivalis感染OSCC细胞的炎性微环境下，CXCL2可能通过EMT作用增强肿瘤细胞增殖和侵袭能力。

关键词: CXC趋化因子配体, 牙龈卟啉单胞菌, 口腔鳞癌, 上皮间质转化