State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha, Hunan 410082, China.
Sci Rep. 2017 Mar 30;7:45377. doi: 10.1038/srep45377.
The transcription factor FOXM1 binds to its consensus sequence at promoters through its DNA binding domain (DBD) and activates proliferation-associated genes. The aberrant overexpression of FOXM1 correlates with tumorigenesis and progression of many cancers. Inhibiting FOXM1 transcriptional activities is proposed as a potential therapeutic strategy for cancer treatment. In this study, we obtained a FOXM1-specific single stranded DNA aptamer (FOXM1 Apt) by SELEX with a recombinant FOXM1 DBD protein as the target of selection. The binding of FOXM1 Apt to FOXM1 proteins were confirmed with electrophoretic mobility shift assays (EMSAs) and fluorescence polarization (FP) assays. Phosphorthioate-modified FOXM1 Apt (M-FOXM1 Apt) bound to FOXM1 as wild type FOXM1 Apt, and co-localized with FOXM1 in nucleus. M-FOXM1-Apt abolished the binding of FOXM1 on its consensus binding sites and suppressed FOXM1 transcriptional activities. Compared with the RNA interference of FOXM1 in cancer cells, M-FOXM1 Apt repressed cell proliferation and the expression of FOXM1 target genes without changing FOXM1 levels. Our results suggest that the obtained FOXM1 Apt could be used as a probe for FOXM1 detection and an inhibitor of FOXM1 transcriptional functions in cancer cells at the same time, providing a potential reagent for cancer diagnosis and treatment in the future.
转录因子 FOXM1 通过其 DNA 结合域 (DBD) 与启动子上的其共有序列结合，并激活与增殖相关的基因。FOXM1 的异常过表达与许多癌症的肿瘤发生和进展相关。抑制 FOXM1 的转录活性被提议作为癌症治疗的一种潜在治疗策略。在这项研究中，我们通过 SELEX 获得了一种 FOXM1 特异性单链 DNA 适体 (FOXM1 Apt)，其靶选为重组 FOXM1 DBD 蛋白。通过电泳迁移率变动分析 (EMSA) 和荧光偏振 (FP) 分析证实了 FOXM1 Apt 与 FOXM1 蛋白的结合。磷酸硫代修饰的 FOXM1 Apt (M-FOXM1 Apt) 与野生型 FOXM1 Apt 一样与 FOXM1 结合，并与 FOXM1 共定位在核内。M-FOXM1-Apt 阻止了 FOXM1 与其共有结合位点的结合，并抑制了 FOXM1 的转录活性。与在癌细胞中对 FOXM1 进行 RNA 干扰相比，M-FOXM1 Apt 抑制了细胞增殖和 FOXM1 靶基因的表达，而不会改变 FOXM1 水平。我们的结果表明，所获得的 FOXM1 Apt 可用作 FOXM1 检测的探针和癌细胞中 FOXM1 转录功能的抑制剂，为未来的癌症诊断和治疗提供了一种潜在的试剂。
