1
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Roy S, Majee P, Sudhakar S, Mishra S, Kalia J, Pradeepkumar PI, Srivatsan SG. Structural elucidation of HIV-1 G-quadruplexes in a cellular environment and their ligand binding using responsive 19F-labeled nucleoside probes. Chem Sci 2024; 15:7982-7991. [PMID: 38817587 PMCID: PMC11134374 DOI: 10.1039/d4sc01755b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 04/23/2024] [Indexed: 06/01/2024] Open
Abstract
Understanding the structure and recognition of highly conserved regulatory segments of the integrated viral DNA genome that forms unique topologies can greatly aid in devising novel therapeutic strategies to counter chronic infections. In this study, we configured a probe system using highly environment-sensitive nucleoside analogs, 5-fluoro-2'-deoxyuridine (FdU) and 5-fluorobenzofuran-2'-deoxyuridine (FBFdU), to investigate the structural polymorphism of HIV-1 long terminal repeat (LTR) G-quadruplexes (GQs) by fluorescence and 19F NMR. FdU and FBFdU, serving as hairpin and GQ sensors, produced distinct spectral signatures for different GQ topologies adopted by LTR G-rich oligonucleotides. Importantly, systematic 19F NMR analysis in Xenopus laevis oocytes gave unprecedented information on the structure adopted by the LTR G-rich region in the cellular environment. The results indicate that it forms a unique GQ-hairpin hybrid architecture, a potent hotspot for selective targeting. Furthermore, structural models generated using MD simulations provided insights on how the probe system senses different GQs. Using the responsiveness of the probes and Taq DNA polymerase stop assay, we monitored GQ- and hairpin-specific ligand interactions and their synergistic inhibitory effect on the replication process. Our findings suggest that targeting GQ and hairpin motifs simultaneously using bimodal ligands could be a new strategy to selectively block the viral replication.
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Affiliation(s)
- Sarupa Roy
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr Homi Bhabha Road Pune 411008 India
| | - Priyasha Majee
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai 400076 India
| | - Sruthi Sudhakar
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai 400076 India
| | - Satyajit Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 India
| | - Jeet Kalia
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 India
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 India
| | - P I Pradeepkumar
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai 400076 India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr Homi Bhabha Road Pune 411008 India
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2
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Wang J, Qiao JQ, Zheng WJ, Lian HZ. Effect of ionic liquids as mobile phase additives on retention behaviors of G-quadruplexes in reversed-phase high performance liquid chromatography. J Chromatogr A 2024; 1715:464604. [PMID: 38176351 DOI: 10.1016/j.chroma.2023.464604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/06/2024]
Abstract
G-quadruplexes (G4s) play an important role in a variety of biological processes and have extensive application prospects. Due to the significance of G4s in physiology and biosensing, studies on G4s have attracted much attention, stimulating the development or improvement of methods for G4 structures and polymorphism analysis. In this work, ionic liquids (ILs) were involved as mobile phase additives in reversed-phase high performance liquid chromatography (RP-HPLC) to analyse G4s with various conformations for the first time. How ILs affected the retention behaviors of G4s was investigated comprehensively. It was found that the addition of ILs markedly enhanced G4 retention, along with obvious amelioration on chromatographic peak shapes and separation. The influence of pH of mobile phase and types of ILs were also included in order to acquire an in-depth understanding. It appeared that the effect of ILs on G4 retention behaviors was the result of a combination of various interactions between G4s with the hydrophobic stationary phase and with the IL-containing mobile phase, where ion pair mechanism and enhanced hydrophobic interaction dominated. The findings of this work revealed that ILs could effectively improve the separation of G4s in RP-HPLC, which was conducive to G4 structural analysis, especially for G4s polymorphism elucidation.
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Affiliation(s)
- Ju Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Jun-Qin Qiao
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.
| | - Wei-Juan Zheng
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Hong-Zhen Lian
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.
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3
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Romano F, Di Porzio A, Iaccarino N, Riccardi G, Di Lorenzo R, Laneri S, Pagano B, Amato J, Randazzo A. G-quadruplexes in cancer-related gene promoters: from identification to therapeutic targeting. Expert Opin Ther Pat 2023; 33:745-773. [PMID: 37855085 DOI: 10.1080/13543776.2023.2271168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/11/2023] [Indexed: 10/20/2023]
Abstract
INTRODUCTION Guanine-rich DNA sequences can fold into four-stranded noncanonical secondary structures called G-quadruplexes (G4s) which are widely distributed in functional regions of the human genome, such as telomeres and gene promoter regions. Compelling evidence suggests their involvement in key genome functions such as gene expression and genome stability. Notably, the abundance of G4-forming sequences near transcription start sites suggests their potential involvement in regulating oncogenes. AREAS COVERED This review provides an overview of current knowledge on G4s in human oncogene promoters. The most representative G4-binding ligands have also been documented. The objective of this work is to present a comprehensive overview of the most promising targets for the development of novel and highly specific anticancer drugs capable of selectively impacting the expression of individual or a limited number of genes. EXPERT OPINION Modulation of G4 formation by specific ligands has been proposed as a powerful new tool to treat cancer through the control of oncogene expression. Actually, most of G4-binding small molecules seem to simultaneously target a range of gene promoter G4s, potentially influencing several critical driver genes in cancer, thus producing significant therapeutic benefits.
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Affiliation(s)
- Francesca Romano
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Anna Di Porzio
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Nunzia Iaccarino
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | | | | | - Sonia Laneri
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Bruno Pagano
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Jussara Amato
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | - Antonio Randazzo
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
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4
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Lu K, Wang HC, Tu YC, Lou PJ, Chang TC, Lin JJ. EGFR suppression contributes to growth inhibitory activity of G-quadruplex ligands in non-small cell lung cancers. Biochem Pharmacol 2023; 216:115788. [PMID: 37683841 DOI: 10.1016/j.bcp.2023.115788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/01/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
Non-small cell lung carcinomas (NSCLCs) commonly harbor activating mutations in the epidermal growth factor receptor (EGFR). Drugs targeting the tyrosine kinase activity of EGFR have shown effectiveness in inhibiting the growth of cancer cells with EGFR mutations. However, the development of additional mutations in cancer cells often leads to the persistence of the disease, necessitating alternative strategies to overcome this challenge. We explored the efficacy of stabilizing the G-quadruplex structure formed in the promoter region of EGFR as a means to suppress its expression and impede the growth of cancer cells with EGFR mutations. We revealed that the carbazole derivative BMVC-8C3O effectively suppressed EGFR expression and demonstrated significant growth inhibition in EGFR-mutated NSCLC cells, both in cell culture and mouse xenograft models. Importantly, the observed repression of EGFR expression and growth inhibition were not exclusive to carbazole derivatives, as several other G-quadruplex ligands exhibited similar effects. The growth-inhibitory activity of BMVC-8C3O is attributed, at least in part, to the repression of EGFR, although it is possible that additional cellular targets are also affected. Remarkably, the growth-inhibitory effect was observed even in osimertinib-resistant cells, indicating that BMVC-8C3O holds promise for treating drug-resistant NSCLC. Our findings present a promising and innovative approach for inhibiting the growth of NSCLC cells with EGFR mutations by effectively suppressing EGFR expression. The demonstrated efficacy of G-quadruplex ligands in this study highlights their potential as candidates for further development in NSCLC therapy.
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Affiliation(s)
- Kai Lu
- Institute of Biochemistry and Molecular Biology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Hsin-Chiao Wang
- Institute of Biochemistry and Molecular Biology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yi-Chen Tu
- Institute of Biochemistry and Molecular Biology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Pei-Jen Lou
- Department of Otolaryngology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei 110, Taiwan
| | - Ta-Chau Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei, 106, Taiwan.
| | - Jing-Jer Lin
- Institute of Biochemistry and Molecular Biology, National Taiwan University College of Medicine, Taipei, Taiwan.
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5
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Liu Y, Li J, Zhang Y, Wang Y, Chen J, Bian Y, Xia Y, Yang MH, Zheng K, Wang KB, Kong LY. Structure of the Major G-Quadruplex in the Human EGFR Oncogene Promoter Adopts a Unique Folding Topology with a Distinctive Snap-Back Loop. J Am Chem Soc 2023; 145:16228-16237. [PMID: 37460135 DOI: 10.1021/jacs.3c05214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
EGFR tyrosine kinase inhibitors have made remarkable success in targeted cancer therapy. However, therapeutic resistance inevitably occurred and EGFR-targeting therapy has been demonstrated to have limited efficacy or utility in glioblastoma, colorectal cancer, and hepatocellular carcinoma. Therefore, there is a high demand for the development of new targets to inhibit EGFR signaling. Herein, we found that the EGFR oncogene proximal promoter sequence forms a unique type of snap-back loop containing G-quadruplex (G4), which can be targeted by small molecules. For the first time, we determined the NMR solution structure of this snap-back EGFR-G4, a three-tetrad-core, parallel-stranded G4 with naturally occurring flanking residues at both the 5'-end and 3'-end. The snap-back loop located at the 3'-end region forms a stable capping structure through two stacked G-triads connected by multiple potential hydrogen bonds. Notably, the flanking residues are consistently absent in reported snap-back G4s, raising the question of whether such structures truly exist under in vivo conditions. The resolved EGFR-G4 structure has eliminated the doubt and showed distinct structural features that distinguish it from the previously reported snap-back G4s, which lack the flanking residues. Furthermore, we found that the snap-back EGFR-G4 structure is highly stable and can form on an elongated DNA template to inhibit DNA polymerase. The unprecedented high-resolution EGFR-G4 structure has thus contributed a promising molecular target for developing alternative EGFR signaling inhibitors in cancer therapeutics. Meanwhile, the two stacked triads may provide an attractive site for specific small-molecule targeting.
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Affiliation(s)
- Yushuang Liu
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Jinzhu Li
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Yongqiang Zhang
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Yingying Wang
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Juannan Chen
- School of Biomedical Sciences, Hunan University, Changsha, Hunan 410082, People's Republic of China
| | - Yuting Bian
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Yuanzheng Xia
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Ming-Hua Yang
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Kewei Zheng
- School of Biomedical Sciences, Hunan University, Changsha, Hunan 410082, People's Republic of China
| | - Kai-Bo Wang
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
| | - Ling-Yi Kong
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu 210009, People's Republic of China
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6
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Khatik SY, Sudhakar S, Mishra S, Kalia J, Pradeepkumar PI, Srivatsan SG. Probing juxtaposed G-quadruplex and hairpin motifs using a responsive nucleoside probe: a unique scaffold for chemotherapy. Chem Sci 2023; 14:5627-5637. [PMID: 37265741 PMCID: PMC10231310 DOI: 10.1039/d3sc00519d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/30/2023] [Indexed: 06/03/2023] Open
Abstract
Paucity of efficient probes and small molecule ligands that can distinguish different G-quadruplex (GQ) topologies poses challenges not only in understanding their basic structure but also in targeting an individual GQ form from others. Alternatively, G-rich sequences that harbour unique chimeric structural motifs (e.g., GQ-duplex or GQ-hairpin junctions) are perceived as new therapeutic hotspots. In this context, the epidermal growth factor receptor (EGFR) gene, implicated in many cancers, contains a 30 nucleotide G-rich segment in the promoter region, which adopts in vitro two unique architectures each composed of a GQ topology (parallel and hybrid-type) juxtaposed with a hairpin domain. Here, we report the use of a novel dual-app probe, C5-trifluoromethyl benzofuran-modified 2'-deoxyuridine (TFBF-dU), in the systematic analysis of EGFR GQs and their interaction with small molecules by fluorescence and 19F NMR techniques. Notably, distinct fluorescence and 19F NMR signals exhibited by the probe enabled the quantification of the relative population of random, parallel and hybrid-type GQ structures under different conditions, which could not be obtained by conventional CD and 1H NMR techniques. Using the fluorescence component, we quantified ligand binding properties of GQs, whereas the 19F label enabled the assessment of ligand-induced changes in GQ dynamics. Studies also revealed that mutations in the hairpin domain affected GQ formation and stability, which was further functionally verified in polymerase stop assay. We anticipate that these findings and useful properties of the nucleoside probe could be utilized in designing and evaluating binders that jointly target both GQ and hairpin domains for enhanced selectivity and druggability.
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Affiliation(s)
- Saddam Y Khatik
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road Pune 411008 India
| | - Sruthi Sudhakar
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai 400076 India
| | - Satyajit Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 India
| | - Jeet Kalia
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 India
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal Bhopal Bypass Road, Bhauri Bhopal 462066 India
| | - P I Pradeepkumar
- Department of Chemistry, Indian Institute of Technology Bombay Mumbai 400076 India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road Pune 411008 India
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7
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Wang J, Qiao J, Zheng W, Lian H. Study on the Interaction of a Peptide Targeting Specific G-Quadruplex Structures Based on Chromatographic Retention Behavior. Int J Mol Sci 2023; 24:ijms24021438. [PMID: 36674950 PMCID: PMC9866954 DOI: 10.3390/ijms24021438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/01/2023] [Accepted: 01/09/2023] [Indexed: 01/12/2023] Open
Abstract
G-quadruplexes (G4s) are of vital biological significance and G4-specific ligands with conformational selectivity show great application potential in disease treatment and biosensing. RHAU, a RNA helicase associated with AU-rich element, exerts biological functions through the mediation of G4s and has been identified to be a G4 binder. Here, we investigated the interactions between the RHAU peptide and G4s with different secondary structures using size exclusion chromatography (SEC) in association with circular dichroism (CD), ultraviolet-visible (UV-Vis) absorption, and native polyacrylamide gel electrophoresis (Native-PAGE). Spectral results demonstrated that the RHAU peptide did not break the main structure of G4s, making it more reliable for G4 structural analysis. The RHAU peptide was found to display a structural selectivity for a preferential binding to parallel G4s as reflected by the distinct chromatographic retention behaviors. In addition, the RHAU peptide exhibited different interactions with intermolecular parallel G4s and intramolecular parallel G4s, providing a novel recognition approach to G4 structures. The findings of this study enriched the insight into the binding of RHAU to G4s with various conformations. It is noteworthy that SEC technology can be easy and reliable for elucidating G4-peptide interactions, especially for a multiple G4 coexisting system, which supplied an alternative strategy to screen novel specific ligands for G4s.
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Affiliation(s)
- Ju Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Junqin Qiao
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
- Correspondence: (J.Q.); (H.L.)
| | - Weijuan Zheng
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Hongzhen Lian
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
- Correspondence: (J.Q.); (H.L.)
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8
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Structural Polymorphism of Guanine Quadruplex-Containing Regions in Human Promoters. Int J Mol Sci 2022; 23:ijms232416020. [PMID: 36555662 PMCID: PMC9786302 DOI: 10.3390/ijms232416020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/05/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Intramolecular guanine quadruplexes (G4s) are non-canonical nucleic acid structures formed by four guanine (G)-rich tracts that assemble into a core of stacked planar tetrads. G4-forming DNA sequences are enriched in gene promoters and are implicated in the control of gene expression. Most G4-forming DNA contains more G residues than can simultaneously be incorporated into the core resulting in a variety of different possible G4 structures. Although this kind of structural polymorphism is well recognized in the literature, there remain unanswered questions regarding possible connections between G4 polymorphism and biological function. Here we report a detailed bioinformatic survey of G4 polymorphism in human gene promoter regions. Our analysis is based on identifying G4-containing regions (G4CRs), which we define as stretches of DNA in which every residue can form part of a G4. We found that G4CRs with higher degrees of polymorphism are more tightly clustered near transcription sites and tend to contain G4s with shorter loops and bulges. Furthermore, we found that G4CRs with well-characterized biological functions tended to be longer and more polymorphic than genome-wide averages. These results represent new evidence linking G4 polymorphism to biological function and provide new criteria for identifying biologically relevant G4-forming regions from genomic data.
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9
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Thermally Induced Transitions of d(G4T4G3) Quadruplexes Can Be Described as Kinetically Driven Processes. Life (Basel) 2022; 12:life12060825. [PMID: 35743856 PMCID: PMC9225023 DOI: 10.3390/life12060825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 11/16/2022] Open
Abstract
DNA sequences that are rich in guanines and can form four-stranded structures are called G-quadruplexes. Due to the growing evidence that they may play an important role in several key biological processes, the G-quadruplexes have captured the interest of several researchers. G-quadruplexes may form in the presence of different metal cations as polymorphic structures formed in kinetically governed processes. Here we investigate a complex polymorphism of d(G4T4G3) quadruplexes at different K+ concentrations. We show that population size of different d(G4T4G3) quadruplex conformations can be manipulated by cooling rate and/or K+ concentration. We use a kinetic model to describe data obtained from DSC, CD and UV spectroscopy and PAGE experiments. Our model is able to describe the observed thermally induced conformational transitions of d(G4T4G3) quadruplexes at different K+ concentrations.
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10
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Monsen RC, DeLeeuw LW, Dean W, Gray R, Chakravarthy S, Hopkins J, Chaires J, Trent J. Long promoter sequences form higher-order G-quadruplexes: an integrative structural biology study of c-Myc, k-Ras and c-Kit promoter sequences. Nucleic Acids Res 2022; 50:4127-4147. [PMID: 35325198 PMCID: PMC9023277 DOI: 10.1093/nar/gkac182] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/03/2022] [Accepted: 03/21/2022] [Indexed: 12/15/2022] Open
Abstract
We report on higher-order G-quadruplex structures adopted by long promoter sequences obtained by an iterative integrated structural biology approach. Our approach uses quantitative biophysical tools (analytical ultracentrifugation, small-angle X-ray scattering, and circular dichroism spectroscopy) combined with modeling and molecular dynamics simulations, to derive self-consistent structural models. The formal resolution of our approach is 18 angstroms, but in some cases structural features of only a few nucleotides can be discerned. We report here five structures of long (34-70 nt) wild-type sequences selected from three cancer-related promoters: c-Myc, c-Kit and k-Ras. Each sequence studied has a unique structure. Three sequences form structures with two contiguous, stacked, G-quadruplex units. One longer sequence from c-Myc forms a structure with three contiguous stacked quadruplexes. A longer c-Kit sequence forms a quadruplex-hairpin structure. Each structure exhibits interfacial regions between stacked quadruplexes or novel loop geometries that are possible druggable targets. We also report methodological advances in our integrated structural biology approach, which now includes quantitative CD for counting stacked G-tetrads, DNaseI cleavage for hairpin detection and SAXS model refinement. Our results suggest that higher-order quadruplex assemblies may be a common feature within the genome, rather than simple single quadruplex structures.
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Affiliation(s)
- Robert C Monsen
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Lynn W DeLeeuw
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - William L Dean
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Robert D Gray
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Jonathan B Chaires
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
| | - John O Trent
- UofL Health Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA
- Department of Medicine, University of Louisville, Louisville, KY 40202, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY 40202, USA
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11
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Grün JT, Schwalbe H. Folding dynamics of polymorphic G-quadruplex structures. Biopolymers 2021; 113:e23477. [PMID: 34664713 DOI: 10.1002/bip.23477] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 12/14/2022]
Abstract
G-quadruplexes (G4), found in numerous places within the human genome, are involved in essential processes of cell regulation. Chromosomal DNA G4s are involved for example, in replication and transcription as first steps of gene expression. Hence, they influence a plethora of downstream processes. G4s possess an intricate structure that differs from canonical B-form DNA. Identical DNA G4 sequences can adopt multiple long-lived conformations, a phenomenon known as G4 polymorphism. A detailed understanding of the molecular mechanisms that drive G4 folding is essential to understand their ambivalent regulatory roles. Disentangling the inherent dynamic and polymorphic nature of G4 structures thus is key to unravel their biological functions and make them amenable as molecular targets in novel therapeutic approaches. We here review recent experimental approaches to monitor G4 folding and discuss structural aspects for possible folding pathways. Substantial progress in the understanding of G4 folding within the recent years now allows drawing comprehensive models of the complex folding energy landscape of G4s that we herein evaluate based on computational and experimental evidence.
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Affiliation(s)
- J Tassilo Grün
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University, Frankfurt/M, Germany.,Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/M, Germany
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12
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Ribaudo G, Ongaro A, Oselladore E, Memo M, Gianoncelli A. Combining Electrospray Mass Spectrometry (ESI-MS) and Computational Techniques in the Assessment of G-Quadruplex Ligands: A Hybrid Approach to Optimize Hit Discovery. J Med Chem 2021; 64:13174-13190. [PMID: 34510895 PMCID: PMC8474113 DOI: 10.1021/acs.jmedchem.1c00962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
![]()
Guanine-rich sequences
forming G-quadruplexes (GQs) are present
in several genomes, ranging from viral to human. Given their peculiar
localization, the induction of GQ formation or GQ stabilization with
small molecules represents a strategy for interfering with crucial
biological functions. Investigating the recognition event at the molecular
level, with the aim of fully understanding the triggered pharmacological
effects, is challenging. Native electrospray ionization mass spectrometry
(ESI-MS) is being optimized to study these noncovalent assemblies.
Quantitative parameters retrieved from ESI-MS studies, such as binding
affinity, the equilibrium binding constant, and sequence selectivity,
will be overviewed. Computational experiments supporting the ESI-MS
investigation and boosting its efficiency in the search for GQ ligands
will also be discussed with practical examples. The combination of
ESI-MS and in silico techniques in a hybrid high-throughput-screening
workflow represents a valuable tool for the medicinal chemist, providing
data on the quantitative and structural aspects of ligand–GQ
interactions.
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Affiliation(s)
- Giovanni Ribaudo
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Alberto Ongaro
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Erika Oselladore
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Maurizio Memo
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Alessandra Gianoncelli
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy
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13
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Gudanis D, Zielińska K, Baranowski D, Kierzek R, Kozłowski P, Gdaniec Z. Impact of a Single Nucleotide Change or Non-Nucleoside Modifications in G-Rich Region on the Quadruplex-Duplex Hybrid Formation. Biomolecules 2021; 11:biom11081236. [PMID: 34439902 PMCID: PMC8392043 DOI: 10.3390/biom11081236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 12/02/2022] Open
Abstract
In this paper, a method to discriminate between two target RNA sequences that differ by one nucleotide only is presented. The method relies on the formation of alternative structures, i.e., quadruplex–duplex hybrid (QDH) and duplex with dangling ends (Dss), after hybridization of DNA or RNA G-rich oligonucleotides with target sequences containing 5′–GGGCUGG–3′ or 5′–GGGCGGG–3′ fragments. Using biophysical methods, we studied the effect of oligonucleotide types (DNA, RNA), non-nucleotide modifications (aliphatic linkers or abasic), and covalently attached G4 ligand on the ability of G-rich oligonucleotides to assemble a G-quadruplex motif. We demonstrated that all examined non-nucleotide modifications could mimic the external loops in the G-quadruplex domain of QDH structures without affecting their stability. Additionally, some modifications, in particular the presence of two abasic residues in the G-rich oligonucleotide, can induce the formation of non-canonical QDH instead of the Dss structure upon hybridization to a target sequence containing the GGGCUGG motif. Our results offer new insight into the sequential requirements for the formation of G-quadruplexes and provide important data on the effects of non-nucleotide modifications on G-quadruplex formation.
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Affiliation(s)
- Dorota Gudanis
- Correspondence: (D.G.); (Z.G.); Tel.: +48-61-852-85-03 (ext. 1286) (D.G.)
| | | | | | | | | | - Zofia Gdaniec
- Correspondence: (D.G.); (Z.G.); Tel.: +48-61-852-85-03 (ext. 1286) (D.G.)
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14
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Mohanty BK, Karam JA, Howley BV, Dalton AC, Grelet S, Dincman T, Streitfeld WS, Yoon JH, Balakrishnan L, Chazin WJ, Long DT, Howe PH. Heterogeneous nuclear ribonucleoprotein E1 binds polycytosine DNA and monitors genome integrity. Life Sci Alliance 2021; 4:4/9/e202000995. [PMID: 34272328 PMCID: PMC8321654 DOI: 10.26508/lsa.202000995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/24/2022] Open
Abstract
hnRNP E1 binds polycytosine tracts of DNA and monitors genome integrity. Heterogeneous nuclear ribonucleoprotein E1 (hnRNP E1) is a tumor suppressor protein that binds site- and structure-specifically to RNA sequences to regulate mRNA stability, facilitate alternative splicing, and suppress protein translation on several metastasis-associated mRNAs. Here, we show that hnRNP E1 binds polycytosine-rich DNA tracts present throughout the genome, including those at promoters of several oncogenes and telomeres and monitors genome integrity. It binds DNA in a site- and structure-specific manner. hnRNP E1-knockdown cells displayed increased DNA damage signals including γ-H2AX at its binding sites and also showed increased mutations. UV and hydroxyurea treatment of hnRNP E1-knockdown cells exacerbated the basal DNA damage signals with increased cell cycle arrest, activation of checkpoint proteins, and monoubiquitination of proliferating cell nuclear antigen despite no changes in deubiquitinating enzymes. DNA damage caused by genotoxin treatment localized to hnRNP E1 binding sites. Our work suggests that hnRNP E1 facilitates functions of DNA integrity proteins at polycytosine tracts and monitors DNA integrity at these sites.
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Affiliation(s)
- Bidyut K Mohanty
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Joseph Aq Karam
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Breege V Howley
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Annamarie C Dalton
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Simon Grelet
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA.,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Toros Dincman
- Division of Hematology and Oncology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - William S Streitfeld
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Je-Hyun Yoon
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Lata Balakrishnan
- Department of Biology, School of Science, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - David T Long
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Philip H Howe
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA .,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
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15
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Grün JT, Blümler A, Burkhart I, Wirmer-Bartoschek J, Heckel A, Schwalbe H. Unraveling the Kinetics of Spare-Tire DNA G-Quadruplex Folding. J Am Chem Soc 2021; 143:6185-6193. [PMID: 33872503 DOI: 10.1021/jacs.1c01089] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The folding of DNA G-quadruplexes (G4) is essential to regulate expression of oncogenes and involves polymorphic long-lived intermediate states. G4 formation requires four G-tracts, but human gene-promoters often contain multiple G-tracts that act as spare-tires. These additional G-tracts are highly conserved and add multiple layers of functional complexity, as they are crucial to maintain G4 function after oxidative damage. Herein, we unravel the folding dynamics of the G4 sequence containing five G-tracts from cMYC, the major proliferation-driving oncogene. We devise a general method to induce folding at constant experimental conditions using a photochemical trapping strategy. Our data dissect the individual kinetics and thermodynamics of the spare-tire mechanism of cMYC-G4.
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Affiliation(s)
- J Tassilo Grün
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Anja Blümler
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Ines Burkhart
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Julia Wirmer-Bartoschek
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Frankfurt 60323, Germany.,Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt am Main, Frankfurt 60323, Germany
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16
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Tan DJY, Winnerdy FR, Lim KW, Phan AT. Coexistence of two quadruplex-duplex hybrids in the PIM1 gene. Nucleic Acids Res 2020; 48:11162-11171. [PMID: 32976598 PMCID: PMC7641742 DOI: 10.1093/nar/gkaa752] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 08/26/2020] [Accepted: 08/31/2020] [Indexed: 12/31/2022] Open
Abstract
The triple-negative breast cancer (TNBC), a subtype of breast cancer which lacks of targeted therapies, exhibits a poor prognosis. It was shown recently that the PIM1 oncogene is highly related to the proliferation of TNBC cells. A quadruplex-duplex hybrid (QDH) forming sequence was recently found to exist near the transcription start site of PIM1. This structure could be an attractive target for regulation of the PIM1 gene expression and thus the treatment of TNBC. Here, we present the solution structures of two QDHs that could coexist in the human PIM1 gene. Form 1 is a three-G-tetrad-layered (3+1) G-quadruplex containing a propeller loop, a lateral loop and a stem-loop made up of three G•C Watson-Crick base pairs. On the other hand, Form 2 is an anti-parallel G-quadruplex comprising two G-tetrads and a G•C•G•C tetrad; the structure has three lateral loops with the middle stem-loop made up of two Watson-Crick G•C base pairs. These structures provide valuable information for the design of G-quadruplex-specific ligands for PIM1 transcription regulation.
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Affiliation(s)
- Derrick J Y Tan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Kah Wai Lim
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
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17
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Maity A, Winnerdy FR, Chang WD, Chen G, Phan AT. Intra-locked G-quadruplex structures formed by irregular DNA G-rich motifs. Nucleic Acids Res 2020; 48:3315-3327. [PMID: 32100003 PMCID: PMC7102960 DOI: 10.1093/nar/gkaa008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/30/2019] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
G-rich DNA sequences with tracts of three or more continuous guanines (G≥3) are known to have high propensity to adopt stable G-quadruplex (G4) structures. Bioinformatic analyses suggest high prevalence of G-rich sequences with short G-tracts (G≤2) in the human genome. However, due to limited structural studies, the folding principles of such sequences remain largely unexplored and hence poorly understood. Here, we present the solution NMR structure of a sequence named AT26 consisting of irregularly spaced G2 tracts and two isolated single guanines. The structure is a four-layered G4 featuring two bi-layered blocks, locked between themselves in an unprecedented fashion making it a stable scaffold. In addition to edgewise and propeller-type loops, AT26 also harbors two V-shaped loops: a 2-nt V-shaped loop spanning two G-tetrad layers and a 0-nt V-shaped loop spanning three G-tetrad layers, which are named as VS- and VR-loop respectively, based on their distinct structural features. The intra-lock motif can be a basis for extending the G-tetrad core and a very stable intra-locked G4 can be formed by a sequence with G-tracts of various lengths including several G2 tracts. Findings from this study will aid in understanding the folding of G4 topologies from sequences containing irregularly spaced multiple short G-tracts.
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Affiliation(s)
- Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Weili Denyse Chang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Gang Chen
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
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18
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Meeting report: Seventh International Meeting on Quadruplex Nucleic Acids (Changchun, P.R. China, September 6–9, 2019). Biochimie 2020; 168:100-109. [DOI: 10.1016/j.biochi.2019.10.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 10/31/2019] [Indexed: 12/24/2022]
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19
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Grün JT, Hennecker C, Klötzner DP, Harkness RW, Bessi I, Heckel A, Mittermaier AK, Schwalbe H. Conformational Dynamics of Strand Register Shifts in DNA G-Quadruplexes. J Am Chem Soc 2019; 142:264-273. [PMID: 31815451 DOI: 10.1021/jacs.9b10367] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The complex folding energy landscape of DNA G-quadruplexes leads to numerous conformations for this functionally important class of noncanonical DNA structures. A new layer of conformational heterogeneity comes from sequences with different numbers of G-nucleotides in each of the DNA G-strands that form the four-stranded G-quartet core. The mechanisms by which G-quadruplexes transition from one folded conformation to another are currently unknown. To address this question, we studied two different G-quadruplexes, selecting a single conformation by blocking hydrogen bonding with photolabile protection groups. Upon irradiation, the block can be released and the kinetics of re-equilibration to the native conformational equilibrium can be determined by time-resolved NMR. We compared the NMR-derived refolding kinetics with data derived from thermal hysteresis folding kinetic experiments and found excellent agreement. The outlined methodological approach allows separation of K+-induced G-quadruplex formation and subsequent refolding and provides key insight into rate-limiting steps of G-quadruplex conformational dynamics.
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Affiliation(s)
- J Tassilo Grün
- Institute for Organic Chemistry and Chemical Biology , Goethe University Frankfurt am Main , Frankfurt 60438 , Germany.,Center of Biomolecular Magnetic Resonance (BMRZ) , Goethe University Frankfurt am Main , Frankfurt 60438 , Germany
| | | | - Dean-Paulos Klötzner
- Institute for Organic Chemistry and Chemical Biology , Goethe University Frankfurt am Main , Frankfurt 60438 , Germany
| | - Robert W Harkness
- Department of Chemistry , McGill University , Montreal H3A 2K6 , Quebec , Canada
| | - Irene Bessi
- Institute of Organic Chemistry , Julius-Maximilians-University Würzburg , Würzburg 97074 , Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology , Goethe University Frankfurt am Main , Frankfurt 60438 , Germany
| | | | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology , Goethe University Frankfurt am Main , Frankfurt 60438 , Germany.,Center of Biomolecular Magnetic Resonance (BMRZ) , Goethe University Frankfurt am Main , Frankfurt 60438 , Germany
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20
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Carvalho J, Lopes-Nunes J, Lopes AC, Cabral Campello MP, Paulo A, Queiroz JA, Cruz C. Aptamer-guided acridine derivatives for cervical cancer. Org Biomol Chem 2019; 17:2992-3002. [PMID: 30810582 DOI: 10.1039/c9ob00318e] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
DNA aptamers represent a way to target cancer cells at a molecular level and continue to be developed with a view to improve treatment and imaging in cancer medicine. AT11-L0, derived from the DNA sequence AT11, forms a single major parallel G-quadruplex (G4) conformation and exhibits an anti-proliferative activity similar to that of AT11 and AS1411 aptamers. On the other side, acridine orange derivatives represent a valuable class of G4 ligands. Herein, we evaluate AT11-L0 G4 as a supramolecular carrier for the delivery of acridine ligands C3, C5 and C8 to HeLa cancer cells. The CD titrations suggest no changes in the chiroptical signal upon addition of an excess of ligands maintaining the parallel G4 topology and C8 stabilizes the structure for more than 20 °C. All the ligands exhibit high affinity (micromolar range) towards AT11-L0 G4, and the respective complexes against nucleolin (nanomolar range) suggesting that the ligands do not negatively affect the recognition of the nucleolin by AT11-L0 G4. NMR studies showed that AT11-L0 forms a G4 containing four G-tetrad layers. Ligand C8 binds AT11-L0 G4 through π-π stacking of the acridine moiety onto the top-tetrad with the involvement of additional interactions with the ligand's side chain and iodobenzene ring. In vitro, the complexes lowered the ligand's cytotoxicity towards non-malignant cells but have a weak inhibitory effect in HeLa cancer cells, except for the AT11-L0-C5 complex. All complexes are efficiently internalized into nucleolin-positive HeLa cells. Overall, these results suggest that AT11-L0 can act as an aptamer by targeting nucleolin and a delivery system of cytotoxic ligands for cervical cancer.
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Affiliation(s)
- Josué Carvalho
- CICS-UBI - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
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21
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Stadlbauer P, Kührová P, Vicherek L, Banáš P, Otyepka M, Trantírek L, Šponer J. Parallel G-triplexes and G-hairpins as potential transitory ensembles in the folding of parallel-stranded DNA G-Quadruplexes. Nucleic Acids Res 2019; 47:7276-7293. [PMID: 31318975 PMCID: PMC6698752 DOI: 10.1093/nar/gkz610] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/26/2019] [Accepted: 07/03/2019] [Indexed: 12/29/2022] Open
Abstract
Guanine quadruplexes (G4s) are non-canonical nucleic acids structures common in important genomic regions. Parallel-stranded G4 folds are the most abundant, but their folding mechanism is not fully understood. Recent research highlighted that G4 DNA molecules fold via kinetic partitioning mechanism dominated by competition amongst diverse long-living G4 folds. The role of other intermediate species such as parallel G-triplexes and G-hairpins in the folding process has been a matter of debate. Here, we use standard and enhanced-sampling molecular dynamics simulations (total length of ∼0.9 ms) to study these potential folding intermediates. We suggest that parallel G-triplex per se is rather an unstable species that is in local equilibrium with a broad ensemble of triplex-like structures. The equilibrium is shifted to well-structured G-triplex by stacked aromatic ligand and to a lesser extent by flanking duplexes or nucleotides. Next, we study propeller loop formation in GGGAGGGAGGG, GGGAGGG and GGGTTAGGG sequences. We identify multiple folding pathways from different unfolded and misfolded structures leading towards an ensemble of intermediates called cross-like structures (cross-hairpins), thus providing atomistic level of description of the single-molecule folding events. In summary, the parallel G-triplex is a possible, but not mandatory short-living (transitory) intermediate in the folding of parallel-stranded G4.
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Affiliation(s)
- Petr Stadlbauer
- Institute of Biophysics of the Czech Academy of Sciences, v. v. i., Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Šlechtitelů 27, 771 46 Olomouc, Czech Republic
| | - Petra Kührová
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Šlechtitelů 27, 771 46 Olomouc, Czech Republic.,Department of Physical Chemistry, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Lukáš Vicherek
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Pavel Banáš
- Institute of Biophysics of the Czech Academy of Sciences, v. v. i., Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Šlechtitelů 27, 771 46 Olomouc, Czech Republic.,Department of Physical Chemistry, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Michal Otyepka
- Institute of Biophysics of the Czech Academy of Sciences, v. v. i., Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Šlechtitelů 27, 771 46 Olomouc, Czech Republic.,Department of Physical Chemistry, Faculty of Science, Palacky University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Lukáš Trantírek
- Institute of Biophysics of the Czech Academy of Sciences, v. v. i., Královopolská 135, 612 65 Brno, Czech Republic.,Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, v. v. i., Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Šlechtitelů 27, 771 46 Olomouc, Czech Republic.,Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
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22
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Kotar A, Rigo R, Sissi C, Plavec J. Two-quartet kit* G-quadruplex is formed via double-stranded pre-folded structure. Nucleic Acids Res 2019; 47:2641-2653. [PMID: 30590801 PMCID: PMC6411839 DOI: 10.1093/nar/gky1269] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 11/16/2018] [Accepted: 12/10/2018] [Indexed: 01/13/2023] Open
Abstract
In the promoter of c-KIT proto-oncogene, whose deregulation has been implicated in many cancers, three G-rich regions (kit1, kit* and kit2) are able to fold into G-quadruplexes. While kit1 and kit2 have been studied in depth, little information is available on kit* folding behavior despite its key role in regulation of c-KIT transcription. Notably, kit* contains consensus sites for SP1 and AP2 transcription factors. Herein, a set of complementary spectroscopic and biophysical methods reveals that kit*, d[GGCGAGGAGGGGCGTGGCCGGC], adopts a chair type antiparallel G-quadruplex with two G-quartets at physiological relevant concentrations of KCl. Heterogeneous ensemble of structures is observed in the presence of Na+ and NH4+ ions, which however stabilize pre-folded structure. In the presence of K+ ions stacking interactions of adenine and thymine residues on the top G-quartet contribute to structural stability together with a G10•C18 base pair and a fold-back motif of the five residues at the 3′-terminal under the bottom G-quartet. The 3′-tail enables formation of a bimolecular pre-folded structure that drives folding of kit* into a single G-quadruplex. Intriguingly, kinetics of kit* G-quadruplex formation matches timescale of transcriptional processes and might demonstrate interplay of kinetic and thermodynamic factors for understanding regulation of c-KIT proto-oncogene expression.
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Affiliation(s)
- Anita Kotar
- Slovenian NMR Center, National Institute of Chemistry, 1000 Ljubljana, Slovenia
| | - Riccardo Rigo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy
| | - Claudia Sissi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, 1000 Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia.,EN-FIST Center of Excellence, 1000 Ljubljana, Slovenia
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23
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Truong THA, Winnerdy FR, Phan AT. An Unprecedented Knot‐like G‐Quadruplex Peripheral Motif. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Thi Hong Anh Truong
- School of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore
- NTU Institute of Structural BiologyNanyang Technological University Singapore 636921 Singapore
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24
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Truong THA, Winnerdy FR, Phan AT. An Unprecedented Knot‐like G‐Quadruplex Peripheral Motif. Angew Chem Int Ed Engl 2019; 58:13834-13839. [DOI: 10.1002/anie.201907740] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Thi Hong Anh Truong
- School of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore
- NTU Institute of Structural BiologyNanyang Technological University Singapore 636921 Singapore
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25
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Winnerdy FR, Bakalar B, Maity A, Vandana JJ, Mechulam Y, Schmitt E, Phan AT. NMR solution and X-ray crystal structures of a DNA molecule containing both right- and left-handed parallel-stranded G-quadruplexes. Nucleic Acids Res 2019; 47:8272-8281. [PMID: 31216034 PMCID: PMC6735952 DOI: 10.1093/nar/gkz349] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/16/2019] [Accepted: 06/13/2019] [Indexed: 01/29/2023] Open
Abstract
Analogous to the B- and Z-DNA structures in double-helix DNA, there exist both right- and left-handed quadruple-helix (G-quadruplex) DNA. Numerous conformations of right-handed and a few left-handed G-quadruplexes were previously observed, yet they were always identified separately. Here, we present the NMR solution and X-ray crystal structures of a right- and left-handed hybrid G-quadruplex. The structure reveals a stacking interaction between two G-quadruplex blocks with different helical orientations and displays features of both right- and left-handed G-quadruplexes. An analysis of loop mutations suggests that single-nucleotide loops are preferred or even required for the left-handed G-quadruplex formation. The discovery of a right- and left-handed hybrid G-quadruplex further expands the polymorphism of G-quadruplexes and is potentially useful in designing a left-to-right junction in G-quadruplex engineering.
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Affiliation(s)
- Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Blaž Bakalar
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - J Jeya Vandana
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yves Mechulam
- Laboratoire de Biochimie, UMR 7654, CNRS, Ecole Polytechnique, Palaiseau 91128, France
| | - Emmanuelle Schmitt
- Laboratoire de Biochimie, UMR 7654, CNRS, Ecole Polytechnique, Palaiseau 91128, France
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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Karg B, Mohr S, Weisz K. Duplex‐Guided Refolding into Novel G‐Quadruplex (3+1) Hybrid Conformations. Angew Chem Int Ed Engl 2019; 58:11068-11071. [DOI: 10.1002/anie.201905372] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Beatrice Karg
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
| | - Swantje Mohr
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
| | - Klaus Weisz
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
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27
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Karg B, Mohr S, Weisz K. Duplex‐gesteuerte Umfaltung in neuartige G‐Quadruplex‐(3+1)‐ Hybridkonformationen. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201905372] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Beatrice Karg
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Deutschland
| | - Swantje Mohr
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Deutschland
| | - Klaus Weisz
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Deutschland
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28
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Distinct biological responses of metastatic castration resistant prostate cancer cells upon exposure to G-quadruplex interacting naphthalenediimide derivatives. Eur J Med Chem 2019; 177:401-413. [PMID: 31158753 DOI: 10.1016/j.ejmech.2019.05.066] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/21/2019] [Accepted: 05/23/2019] [Indexed: 12/23/2022]
Abstract
Small molecules able to bind non-canonical G-quadruplex DNA structures (G4) have been recently tested as novel potential agents for the treatment of prostate cancer thanks to their repression of aberrant androgen receptor gene. However, metastatic castration-resistant prostate cancer (mCRPC), a letal form of prostate cancer, is still incurable. Here we tested two naphthalenediimide derivatives, previously reported as multitarget agents, on a couple of relevant mCRPC cell models (DU145 and PC-3). We showed that these compounds interfere with the RAS/MEK/ERK and PI3K/AKT pathways. Interestingly, both these two biological processes depend upon Epidermal Growth Factor Receptor (EGFR) activation. By means of biological and analytical tools we showed that our compounds are efficient inducers of the structural transition of the EGFR promoter towards a G-quadruplex conformation, ultimately leading to a reduction of the receptor production. The overall result is an interesting cytotoxic profile for these two derivatives. Thanks to their activity at different steps, these compounds can open the way to novel therapeutic approaches for mCRPC that could contribute to escape resistance to selective treatments.
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29
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Sengar A, Vandana J, Chambers VS, Di Antonio M, Winnerdy F, Balasubramanian S, Phan AT. Structure of a (3+1) hybrid G-quadruplex in the PARP1 promoter. Nucleic Acids Res 2019; 47:1564-1572. [PMID: 30551210 PMCID: PMC6379715 DOI: 10.1093/nar/gky1179] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 11/02/2018] [Accepted: 12/12/2018] [Indexed: 01/08/2023] Open
Abstract
Poly (ADP-ribose) polymerase 1 (PARP1) has emerged as an attractive target for cancer therapy due to its key role in DNA repair processes. Inhibition of PARP1 in BRCA-mutated cancers has been observed to be clinically beneficial. Recent genome-mapping experiments have identified a non-canonical G-quadruplex-forming sequence containing bulges within the PARP1 promoter. Structural features, like bulges, provide opportunities for selective chemical targeting of the non-canonical G-quadruplex structure within the PARP1 promoter, which could serve as an alternative therapeutic approach for the regulation of PARP1 expression. Here we report the G-quadruplex structure formed by a 23-nucleotide G-rich sequence in the PARP1 promoter. Our study revealed a three-layered intramolecular (3+1) hybrid G-quadruplex scaffold, in which three strands are oriented in one direction and the fourth in the opposite direction. This structure exhibits unique structural features such as an adenine bulge and a G·G·T base triple capping structure formed between the central edgewise loop, propeller loop and 5' flanking terminal. Given the highly important role of PARP1 in DNA repair and cancer intervention, this structure presents an attractive opportunity to explore the therapeutic potential of PARP1 inhibition via G-quadruplex DNA targeting.
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Affiliation(s)
- Anjali Sengar
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - J Jeya Vandana
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Vicki S Chambers
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Marco Di Antonio
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Shankar Balasubramanian
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge CB2 0RE, UK
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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30
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pH-driven conformational switch between non-canonical DNA structures in a C-rich domain of EGFR promoter. Sci Rep 2019; 9:1210. [PMID: 30718769 PMCID: PMC6362134 DOI: 10.1038/s41598-018-37968-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/17/2018] [Indexed: 01/10/2023] Open
Abstract
EGFR is an oncogene that encodes for a trans-membrane tyrosine kinase receptor. Its mis-regulation is associated to several human cancers that, consistently, can be treated by selective tyrosine kinase inhibitors. The proximal promoter of EGFR contains a G-rich domain located at 272 bases upstream the transcription start site. We previously proved it folds into two main interchanging G-quadruplex structures, one of parallel and one of hybrid topology. Here we present the first evidences supporting the ability of the complementary C-rich strand (EGFR-272_C) to assume an intramolecular i-Motif (iM) structure that, according to the experimental conditions (pH, presence of co-solvent and salts), can coexist with a different arrangement we referred to as a hairpin. The herein identified iM efficiently competes with the canonical pairing of the two complementary strands, indicating it as a potential novel target for anticancer therapies. A preliminary screening for potential binders identified some phenanthroline derivatives as able to target EGFR-272_C at multiple binding sites when it is folded into an iM.
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31
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Whole-Transcriptome Profiling of Canine and Human in Vitro Models Exposed to a G-Quadruplex Binding Small Molecule. Sci Rep 2018; 8:17107. [PMID: 30459395 PMCID: PMC6244004 DOI: 10.1038/s41598-018-35516-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/06/2018] [Indexed: 11/24/2022] Open
Abstract
G-quadruplexes (G4) are secondary nucleic acid structures that have been associated with genomic instability and cancer progression. When present in the promoter of some oncogenes, G4 structures can affect gene regulation and, hence, represent a possible therapeutic target. In this study, RNA-Seq was used to explore the effect of a G4-binding anthraquinone derivative, named AQ1, on the whole-transcriptome profiles of two common cell models for the study of KIT pathways; the human mast cell leukemia (HMC1.2) and the canine mast cell tumor (C2). The highest non-cytotoxic dose of AQ1 (2 µM) resulted in 5441 and 1201 differentially expressed genes in the HMC1.2 and C2 cells, respectively. In both cell lines, major pathways such as cell cycle progression, KIT- and MYC-related pathways were negatively enriched in the AQ1-treated group, while other pathways such as p53, apoptosis and hypoxia-related were positively enriched. These findings suggest that AQ1 treatment induces a similar functional response in the human and canine cell models, and provide news insights into using dogs as a reliable translational model for studying G4-binding compounds.
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32
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Butovskaya E, Heddi B, Bakalar B, Richter SN, Phan AT. Major G-Quadruplex Form of HIV-1 LTR Reveals a (3 + 1) Folding Topology Containing a Stem-Loop. J Am Chem Soc 2018; 140:13654-13662. [PMID: 30299955 PMCID: PMC6202629 DOI: 10.1021/jacs.8b05332] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
Nucleic
acids can form noncanonical four-stranded structures called
G-quadruplexes. G-quadruplex-forming sequences are found in several
genomes including human and viruses. Previous studies showed that
the G-rich sequence located in the U3 promoter region of the HIV-1
long terminal repeat (LTR) folds into a set of dynamically interchangeable
G-quadruplex structures. G-quadruplexes formed in the LTR could act
as silencer elements to regulate viral transcription. Stabilization
of LTR G-quadruplexes by G-quadruplex-specific ligands resulted in
decreased viral production, suggesting the possibility of targeting
viral G-quadruplex structures for antiviral purposes. Among all the
G-quadruplexes formed in the LTR sequence, LTR-III was shown to be the major G-quadruplex conformation in vitro. Here we report the NMR structure of LTR-III in K+ solution, revealing the formation of a unique quadruplex–duplex
hybrid consisting of a three-layer (3 + 1) G-quadruplex scaffold,
a 12-nt diagonal loop containing a conserved duplex-stem, a 3-nt lateral
loop, a 1-nt propeller loop, and a V-shaped loop. Our structure showed
several distinct features including a quadruplex–duplex junction,
representing an attractive motif for drug targeting. The structure
solved in this study may be used as a promising target to selectively
impair the viral cycle.
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Affiliation(s)
- Elena Butovskaya
- School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371 , Singapore.,Department of Molecular Medicine , University of Padua , Padua 35121 , Italy
| | - Brahim Heddi
- School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371 , Singapore.,Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, École Normale Supérieure Paris-Saclay , Cachan 94235 , France
| | - Blaž Bakalar
- School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371 , Singapore
| | - Sara N Richter
- Department of Molecular Medicine , University of Padua , Padua 35121 , Italy
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371 , Singapore
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33
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Benito S, Ferrer A, Benabou S, Aviñó A, Eritja R, Gargallo R. Evaluation of the effect of polymorphism on G-quadruplex-ligand interaction by means of spectroscopic and chromatographic techniques. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 196:185-195. [PMID: 29448171 DOI: 10.1016/j.saa.2018.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/16/2018] [Accepted: 02/04/2018] [Indexed: 06/08/2023]
Abstract
Guanine-rich sequences may fold into highly ordered structures known as G-quadruplexes. Apart from the monomeric G-quadruplex, these sequences may form multimeric structures that are not usually considered when studying interaction with ligands. This work studies the interaction of a ligand, crystal violet, with three guanine-rich DNA sequences with the capacity to form multimeric structures. These sequences correspond to short stretches found near the promoter regions of c-kit and SMARCA4 genes. Instrumental techniques (circular dichroism, molecular fluorescence, size-exclusion chromatography and electrospray ionization mass spectrometry) and multivariate data analysis were used for this purpose. The polymorphism of G-quadruplexes was characterized prior to the interaction studies. The ligand was shown to interact preferentially with the monomeric G-quadruplex; the binding stoichiometry was 1:1 and the binding constant was in the order of 105M-1 for all three sequences. The results highlight the importance of DNA treatment prior to interaction studies.
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Affiliation(s)
- S Benito
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès, 1-11, E-08028 Barcelona, Spain
| | - A Ferrer
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès, 1-11, E-08028 Barcelona, Spain
| | - S Benabou
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès, 1-11, E-08028 Barcelona, Spain
| | - A Aviñó
- Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), CIBER-BBN, Jordi Girona 18-26, E-08034 Barcelona, Spain
| | - R Eritja
- Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), CIBER-BBN, Jordi Girona 18-26, E-08034 Barcelona, Spain
| | - R Gargallo
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Martí i Franquès, 1-11, E-08028 Barcelona, Spain.
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