Jiang Xingkang, Zhang Changwen, Qi Shiyong, Guo Shanqi, Chen Yue, Du E, Zhang Hongtuan, Wang Xiaoming, Liu Ranlu, Qiao Baomin, Yang Kuo, Zhang Zhihong, Xu Yong
Department of Urology, The Second Hospital of Tianjin Medical University, Tianjin Institute of Urology, Tianjin 300211, China.
Department of Oncology, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300112, China.
Oncotarget. 2016 Dec 20;7(51):84893-84906. doi: 10.18632/oncotarget.12753.
Although we and other studies indicated ZNF217 expression was increased in prostate cancer (PCa), the factors mediating its misregulated expression and their oncogenic activity remain largely unexplored. Recent evidence demonstrated that ferroportin (FPN) reduction lead to decreased iron export and increased intercellular iron that consequently aggravates the oncogenic effects of iron. In the present study, ZNF217 was identified as a transcriptional repressor that inhibits FPN expression. Increased of ZNF217 expression led to decreased FPN concentration, coupled with resultant intracellular iron retention, increased iron-related cellular activities and enhanced tumor cell growth. In contrast, decreased of ZNF217 expression restrained tumor cell growth by promoting FPN-driven iron egress. Mechanistic investigation manifested that ZNF217 facilitated the H3K27me3 levels of FPN promoter by interacting with EZH2. Besides, we also found that MAZ increased the transcription level of ZNF217, and subsequently inhibited the FPN expression and their iron-related activities. Strikingly, the expression of MAZ, EZH2 and ZNF217 were concurrently upregulated in PCa, leading to decreased expression of FPN, which induce disordered iron metabolism. Collectively, this study underscored that elevated expression of ZNF217 promotes prostate cancer growth by restraining FPN-conducted iron egress.
尽管我们和其他研究表明锌指蛋白217(ZNF217)在前列腺癌(PCa)中的表达增加,但其表达失调的介导因素及其致癌活性在很大程度上仍未得到探索。最近的证据表明,铁转运蛋白(FPN)减少会导致铁输出减少和细胞间铁增加,从而加剧铁的致癌作用。在本研究中,ZNF217被鉴定为一种抑制FPN表达的转录抑制因子。ZNF217表达增加导致FPN浓度降低,同时导致细胞内铁潴留、铁相关细胞活性增加和肿瘤细胞生长增强。相反,ZNF217表达降低通过促进FPN驱动的铁外流来抑制肿瘤细胞生长。机制研究表明,ZNF217通过与EZH2相互作用促进FPN启动子的H3K27me3水平。此外,我们还发现MAZ增加了ZNF217的转录水平,随后抑制了FPN表达及其铁相关活性。引人注目的是,MAZ、EZH2和ZNF217的表达在PCa中同时上调,导致FPN表达降低,从而诱导铁代谢紊乱。总的来说,这项研究强调ZNF217表达升高通过抑制FPN介导的铁外流促进前列腺癌生长。