Guo Guangcheng, Wang Fang, Han Mingli, Gu Yuanting, Duan Xin, Li Lin
Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University No. 1 Jian She East Road Zhengzhou 450052 China
RSC Adv. 2018 Jan 12;8(5):2740-2750. doi: 10.1039/c7ra12042g. eCollection 2018 Jan 9.
: plasmacytoma variant translocation 1 (PVT1) has been identified as an oncogenic long non-coding RNA (lncRNA) in multiple cancers including breast cancer. However, its molecular basis has not been exhaustively elucidated. : RT-qPCR assay was used to detect PVT1 expression in tissues and cells. The effect of PVT1 and FOXF1 on breast cancer cell proliferation was assessed by MTT, colony formation and cell cycle assays. Cell apoptotic rate was measured by flow cytometry double-staining of Annexin V-FITC and PI. The protein expression patterns of forkhead box f1 (FOXF1) and enhancer of zeste homolog 2 (EZH2) were detected using western blot assays. The subcellular location of PVT1 was analyzed using subcellular fractionation assays. The interaction between PVT1 and EZH2 were demonstrated by RNA-protein pull down and RIP assays. ChIP assay was used to explore whether PVT1 affected FOXF1 expression by recruiting EZH2. assays were performed to further investigate the roles of PVT1 in breast cancer tumorigenesis. : PVT1 expression was elevated in breast cancer tissues and cells. Moreover, higher PVT1 level was positively associated with aggressive pathological status and poor prognosis of breast cancer. PVT1 knockdown suppressed proliferation and induced apoptosis in breast cancer cells. PVT1 silenced FOXF1 expression by recruiting EZH2 to the promoter region of FOXF1, resulting in the increase of H3K27me3 level. EZH2 inhibitor EPZ005687 counteracted PVT1-mediated enrichment effect on H3K27me3 and EZH2 to FOXF1 promoter region. FOXF1 overexpression hampered proliferation and facilitated apoptosis in breast cancer cells. Furthermore, down-regulation of FOXF1 partly abrogated PVT1-knockdown-mediated anti-proliferation and pro-apoptosis effect in breast cancer cells. Finally, PVT1 deficiency suppressed tumor growth by promoting FOXF1 expression . : PVT1 promoted cell proliferation and suppressed apoptosis by epigenetically silencing FOXF1 expression through EZH2 in breast cancer.
浆细胞瘤变异易位1（PVT1）已被确定为包括乳腺癌在内的多种癌症中的一种致癌长链非编码RNA（lncRNA）。然而，其分子基础尚未得到详尽阐明。：采用RT-qPCR检测组织和细胞中PVT1的表达。通过MTT、集落形成和细胞周期检测评估PVT1和FOXF1对乳腺癌细胞增殖的影响。采用Annexin V-FITC和PI双染流式细胞术检测细胞凋亡率。使用蛋白质免疫印迹法检测叉头框f1（FOXF1）和zeste同源物2增强子（EZH2）的蛋白表达模式。采用亚细胞分级分离法分析PVT1的亚细胞定位。通过RNA-蛋白下拉和RIP实验证明PVT1与EZH2之间的相互作用。采用染色质免疫沉淀实验探究PVT1是否通过招募EZH2影响FOXF1表达。进行相关实验进一步研究PVT1在乳腺癌发生中的作用。：PVT1在乳腺癌组织和细胞中表达升高。此外，较高的PVT1水平与乳腺癌侵袭性病理状态和不良预后呈正相关。敲低PVT1可抑制乳腺癌细胞增殖并诱导其凋亡。PVT1通过招募EZH2至FOXF1启动子区域使FOXF1表达沉默，导致H3K27me3水平升高。EZH2抑制剂EPZ005687抵消了PVT1介导的对FOXF1启动子区域H3K27me3和EZH2的富集作用。FOXF1过表达阻碍乳腺癌细胞增殖并促进其凋亡。此外，下调FOXF1部分消除了敲低PVT1介导的对乳腺癌细胞的抗增殖和促凋亡作用。最后，PVT1缺失通过促进FOXF1表达抑制肿瘤生长。：在乳腺癌中，PVT1通过EZH2表观遗传沉默FOXF1表达来促进细胞增殖并抑制凋亡。
