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Suppression of FOXM1 Transcriptional Activities via a Single-Stranded DNA Aptamer Generated by SELEX
Qin Xiang1, Guixiang Tan1, Xia Jiang1
1State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Collaborative Innovation Center for Chemistry and Molecular Medicine, Hunan University, Changsha, Hunan 410082, China.
Abstract:
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.
Insights
We developed a FOXM1-specific DNA aptamer that inhibits cancer cell proliferation by blocking FOXM1 transcriptional activity. This aptamer shows potential for both cancer diagnosis and therapy.
Area of Science:
- Molecular Biology
- Cancer Research
- Biotechnology
Background:
- The transcription factor FOXM1 (Forkhead box M1) is crucial for cell proliferation and is often overexpressed in various cancers.
- Inhibiting FOXM1 activity is a promising strategy for cancer treatment.
Purpose of the Study:
- To develop a FOXM1-specific DNA aptamer for potential use as a diagnostic probe and therapeutic agent.
- To investigate the aptamer's ability to inhibit FOXM1 transcriptional activity and its effect on cancer cell proliferation.
Main Methods:
- Systematic Evolution of Ligands by Exponential Enrichment (SELEX) was used to select a FOXM1-specific aptamer.
- Electrophoretic mobility shift assays (EMSAs) and fluorescence polarization (FP) assays confirmed aptamer binding.
- The aptamer's effect on FOXM1 binding, transcriptional activity, and cancer cell proliferation was assessed.
Main Results:
- A single-stranded DNA aptamer (FOXM1 Apt) specifically binding to the FOXM1 DNA binding domain (DBD) was successfully generated.
- Phosphorothioate modification (M-FOXM1 Apt) enhanced aptamer stability and nuclear localization, maintaining binding affinity.
- M-FOXM1 Apt inhibited FOXM1 binding to its consensus sites, suppressed FOXM1 transcriptional activity, repressed cancer cell proliferation, and downregulated FOXM1 target genes without altering FOXM1 levels.
Conclusions:
- The developed FOXM1 Apt functions as both a detection probe and a functional inhibitor of FOXM1 in cancer cells.
- This aptamer represents a potential novel reagent for cancer diagnosis and therapeutic intervention.