EZH2 suppresses the nucleotide excision repair in nasopharyngeal carcinoma by silencing XPA gene

详细信息    查看全文

• 作者：Yuxiang Huang ; Xuanyi Wang ; Xiaoshuang Niu ; Xiaoshen Wang ; Rui Jiang ; Tingting Xu ; Yong Liu ; Liping Liang ; Xiaomin Ou ; Xing Xing ; Weiwei Li and Chaosu Hu
• 刊名：Molecular Carcinogenesis
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：56
• 期：2
• 页码：447-463
• 全文大小：4825K
• ISSN：1098-2744

文摘

The enhancer of zeste homolog 2 (EZH2) is involved in a number of fundamental pathological processes of cancer. However, its role in DNA repair pathway is still unclear. Here, we have identified XPA as a novel target gene of EZH2 via a DNA repair pathway PCR array. XPA plays a pivot role in nucleotide excision repair (NER). The expression of XPA was significantly increased by EZH2 specific inhibitor GSK126 or lentiviral shEZH2 in nasopharyngeal carcinoma (NPC) CNE and 8F cell lines. Chromatin immunoprecipitation assay demonstrated that EZH2 catalyzes H3K27 trimethylation at the XPA promoters. Furthermore, we validated the negative correlation of EZH2 and XPA in a NPC tissue microarray by immunohistochemistry staining. We also found that high expression of EZH2 was positively correlated with advanced T, N, and AJCC stage of NPC; and low expression of XPA was positively correlated with advanced T and N stage. In NPC cell lines, increased XPA expression by EZH2 inhibition resulted in a more rapid removal of UVC induced 6-4PP- and CPD-DNA adducts, as well as enhanced efficiency of DNA repair after UVC irradiation as detected by the Comet assay and immunofluorescence staining of γH2Ax. Consistently, increased cell clonogenic survival, decreased apoptosis, and necrosis after UVC irradiation, and increased resistance to DNA damaging agent cisplatin was also observed in EZH2 inhibited cells. These results illustrate that EZH2 may promote carcinogenesis and cancer development of NPC by transcriptional repression of XPA gene and inactivation of NER pathway.