Chan Tze-Sian, Lee Kun-Lin, Hung Ching-Sheng, Chiang Hsin-Pei, Chung Chia-Chen, Liang Yu-Chih
Division of Gastroenterology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Division of Gastroenterology, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
Mol Cell Biochem. 2025 Mar;480(3):1685-1699. doi: 10.1007/s11010-024-05087-w. Epub 2024 Aug 7.
The CCND1 mRNA possesses at least two distinct lengths of the 3'-untranslated region (3'UTR), with the long isoform containing multiple AU-rich elements (AREs). The tandem zinc finger (TZF) domains of human ZFP36 family members have the capacity to bind to AREs and promote mRNA degradation. Our previous study demonstrated that mutations in the TZF domain of ZFP36L1 or ZFP36L2 increased the CCND1 expression. In this study, we investigated whether ZFP36L1 and ZFP36L2 could downregulate the expression of the long 3'UTR isoform of CCND1 mRNA in human colorectal cancer (CRC) cells. Firstly, the Gene Expression Profiling Interactive Analysis 2 database indicated downregulation of ZFP36 and ZFP36L1, while E2F1 and CCND1 were upregulated in human CRC tissues compared to normal colorectal tissues. Overexpression of ZFP36L1 and/or ZFP36L2 in T-REx-293, DLD-1, and HCT116 cells led to a decrease in the total CCND1, long isoform ratio of CCND1 mRNA, and E2F1 expression. Conversely, knockdown of ZFP36L1 and ZFP36L2 in HCT116 cells resulted in an increase in total CCND1, long isoform ratio of CCND1 mRNA, and E2F1 expression. Knockdown of E2F1 decreased CCND1 expression, indicating a potential role for E2F1 in regulating CCND1 expression at the transcriptional level. These findings suggest that ZFP36L1 and ZFP36L2 play a negative role in CCND1 expression. The underlying mechanisms might involve the reduction of E2F1 transactivation at the transcriptional level and the promotion of AREs-mediated decay of the long 3'UTR isoform of CCND1 through posttranscriptional processes.
CCND1 mRNA具有至少两种不同长度的3'非翻译区（3'UTR），其中长异构体包含多个富含AU的元件（ARE）。人类ZFP36家族成员的串联锌指（TZF）结构域能够与ARE结合并促进mRNA降解。我们之前的研究表明，ZFP36L1或ZFP36L2的TZF结构域中的突变会增加CCND1的表达。在本研究中，我们调查了ZFP36L1和ZFP36L2是否能下调人结肠直肠癌（CRC）细胞中CCND1 mRNA长3'UTR异构体的表达。首先，基因表达谱交互式分析2数据库表明，与正常结肠组织相比，人CRC组织中ZFP36和ZFP36L1表达下调，而E2F1和CCND1表达上调。在T-REx-293、DLD-1和HCT116细胞中过表达ZFP36L1和/或ZFP36L2导致总CCND1、CCND1 mRNA长异构体比例和E2F1表达降低。相反，在HCT116细胞中敲低ZFP36L1和ZFP36L2导致总CCND1、CCND1 mRNA长异构体比例和E2F1表达增加。敲低E2F1会降低CCND1表达，表明E2F1在转录水平调控CCND1表达中具有潜在作用。这些发现表明，ZFP36L1和ZFP36L2在CCND1表达中起负向作用。潜在机制可能涉及转录水平上E2F1反式激活的减少以及通过转录后过程促进CCND1长3'UTR异构体的ARE介导的衰变。
