敲低EZH2表达抑制人舌鳞状细胞癌侵袭迁移能力的研究

  目的  探究Zeste同源增强子（enhancer of zeste homolog 2，EZH2）能否调控miR-200b/a/429的表达，进而影响人舌鳞状细胞癌的侵袭和转移。  方法  利用小干扰RNA（siRNAs）敲低舌鳞状细胞癌SCC15和UM-1细胞系中EZH2的表达。Western blot法检测EZH2和上皮-间质转化（EMT）相关蛋白的表达水平。q-PCR检测敲低EZH2后miR-200b/a/429的表达水平。Transwell实验和划痕实验检测舌鳞癌细胞的侵袭和迁移能力。最后通过免疫荧光实验观测细胞骨架的改变。免疫组织化学法和q-PCR检测人舌鳞状细胞癌标本中EZH2的表达。  结果  siRNAs能够显著地敲低EZH2表达，进而使miR-200b/a/429表达水平升高；E-cadherin表达水平升高，而N-cadherin、Vimentin、MMP-2、MMP-9蛋白表达水平下降；si-EZH2组肿瘤细胞的侵袭和迁移能力明显降低。淋巴结转移阳性的人舌鳞状细胞癌标本中EZH2表达水平高于淋巴结转移阴性（P < 0.01）。  结论  EZH2通过抑制miR-200b/a/429的表达水平，进而促进了人舌鳞状细胞癌的侵袭和迁移。 

Suppression on invasion and migration of human tongue squamous cell carcinoma after knocking down EZH2 expression

  Objective  To explore whether EZH2 can regulate the expression of miR-200b/a/429 and, thus, affect human tongue squamous cell carcinoma (TSCC).  Methods  EZH2 was knocked down in TSCC lines SCC15 and UM-1 with siRNA (si-EZH2) method. The expression levels of EZH2 and epithelial mesenchymal transition related proteins were detected by Western blot. qPCR was used to determine the expression level of miR-200b/a/429 after knockdown of EZH2. Transwell and wound-healing assays were employed to detect the invasion and migration ability of tumor cells. The cytoskeleton was observed with an immunofluorescence assay. EZH2 expression in human head and neck squamous cell carcinoma (HNSCC) was detected by an immunofluorescence assay and qPCR.  Results  EZH2 was significantly knocked down by siRNA, thus the expression level of miR-200b/a/429 and E-cadherin increased. While the expression of the N-cadherin, Vimentin, MMP2, and MMP9 proteins decreased; the migration and invasion of HNSCC cells in the si-EZH2 group was markedly inhibited. The EZH2 expression level in patients with lymph node metastasis in HNSCC specimens was higher than those without lymph node metastasis (P < 0.01).  Conclusions  EZH2 inhibits the expression of miR-200b/a/429 and promotes the invasion and migration of TSCC cells.