[摘要] 目的：探究lncRNA XIST/miR-34a-5p/SIRT6 分子轴调控口腔鳞癌细胞增殖和转移及其分子机制。方法：收集2013年3 月至2018 年3 月在青岛市口腔医院就诊的OSCC患者47 例癌组织和癌旁组织标本，采用qPCR检测OSCC患者组织及细胞系中lncRNA XIST、miR-34a-5p、SIRT6 mRNA 的表达，WB检测OSCC 患者组织及细胞系中SIRT6、Ki67、pcDNA、cleaved-caspase3、cleaved-caspase8、E-cadherin、Vimentin 蛋白的表达，采用CCK-8 实验检测敲降lncRNA XIST对Cal-27 及Tca-8113 细胞增殖的影响，Transwell 小室法检测Cal-27 及Tca-8113 细胞迁移及侵袭；流式细胞术检测Cal-27 及Tca-8113 细胞凋亡情况，双荧光素酶报告基因检测lncRNA XIST与miR-34a-5p、miR-34a-5p 与SIRT6 靶向结合关系。结果：lncRNA XIST和SIRT6 在OSCC患者癌组织及细胞系中高表达（均P<0.05），miR-34a-5p 则呈低表达（P<0.01）；敲降lncRNA XIST抑制OSCC细胞的增殖、迁移及侵袭并促进细胞凋亡（均P<0.01），同时转染miR-34a-5p 抑制剂或pcDNA-SIRT6 载体作用则相反；敲降lncRNA XIST 促进OSCC细胞中增殖及转移相关蛋白表达（均P<0.01），同时转染miR-34a-5p 抑制剂或pcDNA-SIRT6 载体作用则相反；lncRNA XIST 与miR-34a 靶向结合，miR-34a 与SIRT6 靶向结合；lncRNA XIST 通过靶向miR-34a-5p 上调SIRT6 表达（P<0.01）。结论：lncRNA XIST/miR-34a-5p/SIRT6 分子轴能够调控OSCC细胞增殖及转移，为OSCC治疗提供潜在靶点。

[Abstract] Objective: To investigate the molecular mechanisms of lncRNA XIST/miR-34a-5p/SIRT6 axis regulating the proliferation and metastasis of oral squamous cell carcinoma (OSCC) cells. Methods: Specimens of tumor tissues and paracancer tissues of 47 patients with OSCC, who visited the Qingdao Stomatological Hospital from March 2013 to March 2018, were enrolled in this study. qPCR was performed to measure the mRNA expressions of lncRNA XIST, miR-34a-5p and SIRT6 in OSCC tissues and cell lines. WB was performed to measure the protein levels of SIRT6, Ki67, pcDNA, cleaved-caspase3, cleaved-caspase8, E-cadherin and vimentin in OSCC tissues and cell lines. CCK-8 assay was performed to observe the effect of lncRNA XIST knockdown on proliferation of Cal-27 and Tca-8113 cells; Tanswell assay was performed to detect migration and invasion of Cal-27 and Tca-8113 cells; flow cytometry was performed to detect the apoptosis of Cal-27 and Tca-8113 cells; and dual luciferase reporter assay was performed to verify the relationship between lncRNA XIST and miR-34a, or miR-34a and SIRT6. Results: Expressions of lncRNA XIST and SIRT6 were up-regulated in OSCC tissues and cell lines (all P<0.05), reversely, miR-34a-5p was down-regulated in OSCC tissues and cell lines (P<0.01). lncRNA XIST knockdown significantly suppressed OSCC cells proliferation, migration and invasion, and induced apoptosis of OSCC cells (all P<0.01); however, simultaneous transfection with miR-34a-5p inhibitor or pcDNA-SIRT6 vector exerted opposite effect.lncRNA XIST knockdown significantly increased cell proliferation and metastasis related protein expression in OSCC cells (all P<0.01), and simultaneous transfection with miR-34a-5p inhibitor or pcDNA-SIRT6 vector exerted opposite effect. In addition, lncRNA XIST directly targeted miR-34a-5p, and miR-34a-5p targeted SIRT6, lncRNA XIST upregulated SIRT6 expression via inhibiting miR-34a-5p (P<0.01). Conclusion: Taken together, lncRNA XIST/miR-34a-5p/SIRT6 axis regulates the proliferation and metastasis of OSCC cells and provides potential therapeutic targets for OSCC.