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Narum S, Deal B, Ogasawara H, Mancuso JN, Zhang J, Salaita K. An Endosomal Escape Trojan Horse Platform to Improve Cytosolic Delivery of Nucleic Acids. ACS Nano 2024; 18:6186-6201. [PMID: 38346399 PMCID: PMC10906071 DOI: 10.1021/acsnano.3c09027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/11/2023] [Accepted: 12/26/2023] [Indexed: 02/17/2024]
Abstract
Endocytosis is a major bottleneck toward cytosolic delivery of nucleic acids, as the vast majority of nucleic acid drugs remain trapped within endosomes. Current trends to overcome endosomal entrapment and subsequent degradation provide varied success; however, active delivery agents such as cell-penetrating peptides have emerged as a prominent strategy to improve cytosolic delivery. Yet, these membrane-active agents have poor selectivity for endosomal membranes, leading to toxicity. A hallmark of endosomes is their acidic environment, which aids in degradation of foreign materials. Here, we develop a pH-triggered spherical nucleic acid that provides smart antisense oligonucleotide (ASO) release upon endosomal acidification and selective membrane disruption, termed DNA EndosomaL Escape Vehicle Response (DELVR). We anchor i-Motif DNA to a nanoparticle (AuNP), where the complement strand contains both an ASO sequence and a functionalized endosomal escape peptide (EEP). By orienting the EEP toward the AuNP core, the EEP is inactive until it is released through acidification-induced i-Motif folding. In this study, we characterize a small library of i-Motif duplexes to develop a structure-switching nucleic acid sequence triggered by endosomal acidification. We evaluate antisense efficacy using HIF1a, a hypoxic indicator upregulated in many cancers, and demonstrate dose-dependent activity through RT-qPCR. We show that DELVR significantly improves ASO efficacy in vitro. Finally, we use fluorescence lifetime imaging and activity measurement to show that DELVR benefits synergistically from nuclease- and pH-driven release strategies with increased ASO endosomal escape efficiency. Overall, this study develops a modular platform that improves the cytosolic delivery of nucleic acid therapeutics and offers key insights for overcoming intracellular barriers.
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Affiliation(s)
- Steven Narum
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - Brendan Deal
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Hiroaki Ogasawara
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | | | - Jiahui Zhang
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - Khalid Salaita
- Department
of Biomedical Engineering, Georgia Institute
of Technology and Emory University, Atlanta, Georgia 30322, United States
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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2
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Ghezzo M, Trajkovski M, Plavec J, Sissi C. A Screening Protocol for Exploring Loop Length Requirements for the Formation of a Three Cytosine-Cytosine + Base-Paired i-Motif. Angew Chem Int Ed Engl 2023; 62:e202309327. [PMID: 37611164 DOI: 10.1002/anie.202309327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 08/25/2023]
Abstract
DNA sequences containing at least four runs of repetitive cytosines can fold into tetra-helical structures called i-Motifs (iMs). The interest in these DNA secondary structures is increasing due to their therapeutical and technological applications. Still, limited knowledge of their folding requirements is currently available. We developed a novel step-by-step pipeline for the systematic screening of putative iM-forming model sequences. Focusing on structures comprising only three cytosine-cytosine+ base pairs, we investigated what the minimal lengths of the loops required for formation of an intra-molecular iM are. Our data indicate that two and three nucleotides are required to connect the strands through the minor and majorgrooves of the iM, respectively. Additionally, they highlight an asymmetric behavior according to the distribution of the cytosines. Specifically, no sequence containing a single cytosine in the first and third run was able to fold into intra-molecular iMs with the same stability of those formed when the first and the third run comprise two cytosines. This knowledge represents a step forward toward the development of prediction tools for the proper identification of biologically functional iMs, as well as for the rational design of these secondary structures as technological devices.
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Affiliation(s)
- Michele Ghezzo
- Department of Pharmaceutical and Pharmacological Science, University of Padua, Via Marzolo 5, 35131, Padua, Italy
| | - Marko Trajkovski
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
| | - Claudia Sissi
- Department of Pharmaceutical and Pharmacological Science, University of Padua, Via Marzolo 5, 35131, Padua, Italy
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3
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Chikhale RV, Guneri D, Yuan R, Morris CJ, Waller ZAE. Identification of sugar-containing natural products that interact with i-motif DNA. Bioorg Med Chem Lett 2022; 73:128886. [PMID: 35835380 DOI: 10.1016/j.bmcl.2022.128886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 11/30/2022]
Abstract
There are thousands of compounds shown to interact with G-quadruplex DNA, yet very few which target i-motif (iM) DNA. Previous work showed that tobramycin can interact with iM- DNA, indicating the potential for sugar-molecules to target these structures. Computational approaches indicated that the sugar-containing natural products baicalin and geniposidic acid had potential to target iM-DNA. We assessed the DNA interacting properties of these compounds using FRET-based DNA melting and a fluorescence-based displacement assay using iM-DNA structures from the human telomere and the insulin linked polymorphic region (ILPR), as well as complementary G-quadruplex and double stranded DNA. Both baicalin and geniposidic acid show promise as iM-interacting compounds with potential for use in experiments into the structure and function of i-motif forming DNA sequences and present starting points for further synthetic development of these as probes for iM-DNA.
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Affiliation(s)
| | - Dilek Guneri
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Robert Yuan
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | | | - Zoë A E Waller
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK.
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4
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Sanchez-Martin V, Lopez-Pujante C, Soriano-Rodriguez M, Garcia-Salcedo JA. An Updated Focus on Quadruplex Structures as Potential Therapeutic Targets in Cancer. Int J Mol Sci 2020; 21:ijms21238900. [PMID: 33255335 PMCID: PMC7734589 DOI: 10.3390/ijms21238900] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/13/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023] Open
Abstract
Non-canonical, four-stranded nucleic acids secondary structures are present within regulatory regions in the human genome and transcriptome. To date, these quadruplex structures include both DNA and RNA G-quadruplexes, formed in guanine-rich sequences, and i-Motifs, found in cytosine-rich sequences, as their counterparts. Quadruplexes have been extensively associated with cancer, playing an important role in telomere maintenance and control of genetic expression of several oncogenes and tumor suppressors. Therefore, quadruplex structures are considered attractive molecular targets for cancer therapeutics with novel mechanisms of action. In this review, we provide a general overview about recent research on the implications of quadruplex structures in cancer, firstly gathering together DNA G-quadruplexes, RNA G-quadruplexes as well as DNA i-Motifs.
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Affiliation(s)
- Victoria Sanchez-Martin
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Microbiology Unit, University Hospital Virgen de las Nieves, Biosanitary Research Institute IBS, Granada, 18014 Granada, Spain
- Department of Biochemistry, Molecular Biology III and Immunology, University of Granada, 18016 Granada, Spain
| | - Carmen Lopez-Pujante
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
| | - Miguel Soriano-Rodriguez
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Centre for Intensive Mediterranean Agrosystems and Agri-food Biotechnology (CIAMBITAL), University of Almeria, 04001 Almeria, Spain
- Correspondence: (M.S.-R.); (J.A.G.-S.); Tel.: +34-958715500 (M.S.-R.); +34-958715500 (J.A.G.-S.)
| | - Jose A. Garcia-Salcedo
- GENYO, Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; (V.S.-M.); (C.L.-P.)
- Microbiology Unit, University Hospital Virgen de las Nieves, Biosanitary Research Institute IBS, Granada, 18014 Granada, Spain
- Correspondence: (M.S.-R.); (J.A.G.-S.); Tel.: +34-958715500 (M.S.-R.); +34-958715500 (J.A.G.-S.)
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5
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Navarro A, Benabou S, Eritja R, Gargallo R. Influence of pH and a porphyrin ligand on the stability of a G-quadruplex structure within a duplex segment near the promoter region of the SMARCA4 gene. Int J Biol Macromol 2020; 159:383-393. [PMID: 32416304 DOI: 10.1016/j.ijbiomac.2020.05.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/06/2020] [Accepted: 05/09/2020] [Indexed: 12/20/2022]
Abstract
In a previous work, the formation of G-quadruplex structures in a 44-nucleotide long sequence found near the promoter region of the SMARCA4 gene was reported. The central 25 nucleotides were able to fold into an antiparallel G-quadruplex structure, the stability of which was pH-dependent. In the present work, the effect of the presence of lateral nucleotides and the complementary cytosine-rich strand on the stability of this G-quadruplex has been characterized. Moreover, the role of the model ligand TMPyP4 has been studied. Spectroscopic and separation techniques, as well as multivariate data analysis methods, have been used with these purposes. The results have shown that stability of the G-quadruplex as a function of pH or temperature is greatly reduced in the presence of the lateral nucleotides. The influence of the complementary strand does not prevent the formation of the G-quadruplex. Moreover, attempts to modulate the equilibria by an external ligand led us to determine the influence of the TMPyP4 porphyrin on these complex equilibria. This study could eventually help to understand the regulation of SMARCA4 expression.
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Affiliation(s)
- Alba Navarro
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Spain
| | - Sanae Benabou
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Spain; Université de Bordeaux, CNRS, Inserm, Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle (ARNA, U1212, UMR5320), IECB, 2 rue Robert Escarpit, 33600 Pessac, France
| | - Ramon Eritja
- Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, Networking Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
| | - Raimundo Gargallo
- Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Spain.
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6
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Duan J, Wang X, Kizer ME. Biotechnological and Therapeutic Applications of Natural Nucleic Acid Structural Motifs. Top Curr Chem (Cham) 2020; 378:26. [PMID: 32067108 DOI: 10.1007/s41061-020-0290-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/11/2020] [Indexed: 11/28/2022]
Abstract
Genetic information and the blueprint of life are stored in the form of nucleic acids. The primary sequence of DNA, read from the canonical double helix, provides the code for RNA and protein synthesis. Yet these already-information-rich molecules have higher-order structures which play critical roles in transcription and translation. Uncovering the sequences, parameters, and conditions which govern the formation of these structural motifs has allowed researchers to study them and to utilize them in biotechnological and therapeutic applications in vitro and in vivo. This review covers both DNA and RNA structural motifs found naturally in biological systems including catalytic nucleic acids, non-coding RNA, aptamers, G-quadruplexes, i-motifs, and Holliday junctions. For each category, an overview of the structural characteristics, biological prevalence, and function will be discussed. The biotechnological and therapeutic applications of these structural motifs are highlighted. Future perspectives focus on the addition of proteins and unnatural modifications to enhance structural stability for greater applicability.
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Affiliation(s)
- Jinwei Duan
- Department of Chemistry and Materials Science, College of Sciences, Chang'an University, Xi'an, 710064, Shaanxi, People's Republic of China.
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Xing Wang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Megan E Kizer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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7
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Wang X, Qian C, Wang X, Li T, Guo Z. Guanine-guided time-resolved luminescence recognition of DNA modification and i-motif formation by a terbium(III)-platinum(II) complex. Biosens Bioelectron 2019; 150:111841. [PMID: 31735621 DOI: 10.1016/j.bios.2019.111841] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/21/2019] [Accepted: 11/01/2019] [Indexed: 12/31/2022]
Abstract
Site-specific recognition of DNA modification or the formation of noncanonical structures has important applications in molecular biology, disease diagnosis, and gene expression analysis. In this study, we introduce a guanine-guided sensing tool using a terbium(III)-platinum(II) complex (TPC) as a time-resolved luminescence probe to site-specifically recognize DNA modification and i-motif formation in aqueous solution. The probe is composed of a TbIII center as the luminescent reporter and two PtII units as the receptor for guanine (G) nucleobase. TPC exhibits remarkable reaction selectivity for guanine nucleotides over other nucleotides, giving rise to a significant increase in luminescence. The luminescence enhancement of TPC is mainly attributed to an energy transfer from G base to the TbIII center after the specific coordination of PtII with N7 of guanine (N7-G), which would be facilitated by the phosphates through promoting the departure of coordinated water and bringing G closer to TbIIIvia noncovalent interactions. Based on such sensing feature, the enhanced luminescence of TPC sensitized by G nucleotides can correspondingly decrease upon N7-G modifications of DNA or i-motif formation through constructing simple guanine-guided sensing tools. This probe would provide a useful strategy for site-specific recognition of DNA for extensive purposes.
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Affiliation(s)
- Xiaohui Wang
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, PR China; State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, PR China.
| | - Chengyuan Qian
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, 211816, PR China
| | - Xiaoyong Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing, 210093, PR China.
| | - Tuanjie Li
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, PR China
| | - Zijian Guo
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, PR China.
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8
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Iaccarino N, Di Porzio A, Amato J, Pagano B, Brancaccio D, Novellino E, Leardi R, Randazzo A. Assessing the influence of pH and cationic strength on i-motif DNA structure. Anal Bioanal Chem 2019; 411:7473-9. [PMID: 31529141 DOI: 10.1007/s00216-019-02120-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 09/02/2019] [Indexed: 10/26/2022]
Abstract
The i-motif is a biologically relevant non-canonical DNA structure formed by cytosine-rich sequences. Despite the importance of the factors affecting the formation/stability of such a structure, like pH, cation type and concentration, no systematic study that simultaneously analysed their effect on the i-motif in vitro has been carried out so far. Therefore, here we report a systematic study that aims to evaluate the effect of these factors, and their possible interaction, on the formation of an i-motif structure. Our results confirm that pH plays the main role in i-motif formation. However, we demonstrate that the effect of the cation concentration on the i-motif is strictly dependent on the pH, while no significant differences are observed among the investigated cation types. Graphical abstract.
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9
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Abstract
In addition to the canonical B-form structure, DNA can adopt alternative conformations including Z DNA, triplex DNA, as well as G4 and i-Motif quadruplex structures. Such structures have been shown to form in cells in a dynamic manner. Monoclonal antibodies against such structures represent key tools to study the biological functions of these structures. Here we provide protocols for the generation of antibody fragments against structured DNA using phage display selections.
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10
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Li H, Hai J, Zhou J, Yuan G. The formation and characteristics of the i-motif structure within the promoter of the c-myb proto-oncogene. J Photochem Photobiol B 2016; 162:625-632. [PMID: 27487467 DOI: 10.1016/j.jphotobiol.2016.07.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/21/2016] [Accepted: 07/24/2016] [Indexed: 12/11/2022]
Abstract
C-myb proto-oncogene is a potential therapeutic target for some human solid tumors and leukemias. A long cytosine-rich sequence, which locates the downstream of the transcription initiation site, is demonstrated to fold into an intramolecular i-motif DNA using electrospray ionization mass spectrometry (ESI-MS) and circular dichroism (CD) spectroscopy. Effects of factors, including the pH value, the number of C:C(+) dimers, the concentration of buffer, the molecular crowding condition, and the coexistence of the complementary DNA, on the formation and the structural stability of the i-motif DNA are systematically studied. We have demonstrated that the i-motif folding in the c-myb promoter could be accelerated upon synergistic physiological stimuli including intracellular molecular crowding and low pH values, as well as the large number of the i-motif C:C(+) dimers. Meanwhile, various inputs, such as acids/bases and metal ions, have exhibited their abilities in controlling the conformational switch of the c-myb GC-rich DNA. Acidic pH values and the presence of K(+) ions can induce the dissociation of the double helix. Our present strategy can greatly extend the potential usages of i-motif DNA molecules with specific sequences as conformational switch-controlled devices. Moreover, this work demonstrates the superiority of CD spectroscopy associated with ESI-MS as a rapid, more cost-effective and sensitive structural change responsive method in the research of DNA conformational switching.
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Affiliation(s)
- Huihui Li
- National and Local Joint Engineering Research Center of Biomedical Functional Materials, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China; Department of Chemistry, University of British Columbia, Vancouver V6T 1Z1, Canada.
| | - Jinhui Hai
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; National and Local Joint Engineering Research Center of Biomedical Functional Materials, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023, China
| | - Jiang Zhou
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Gu Yuan
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
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11
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Kang BH, Gao ZF, Li N, Shi Y, Li NB, Luo HQ. Thiazole orange as a fluorescent probe: Label-free and selective detection of silver ions based on the structural change of i-motif DNA at neutral pH. Talanta 2016; 156-157:141-146. [PMID: 27260446 DOI: 10.1016/j.talanta.2016.05.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/27/2016] [Accepted: 05/01/2016] [Indexed: 02/05/2023]
Abstract
Silver ions have been widely applied to many fields and have harmful effects on environments and human health. Herein, a label-free optical sensor for Ag(+) detection is constructed based on thiazole orange (TO) as a fluorescent probe for the recognition of i-motif DNA structure change at neutral pH. Ag(+) can fold a C-rich single stranded DNA sequence into i-motif DNA structure at neutral pH and that folding is reversible by chelation with cysteine (Cys). The DNA folding process can be indicated by the fluorescence change of TO, which is non-fluorescent in free molecule state and emits strong fluorescence after the incorporation with i-motif DNA. Thus, a rapid, sensitive, and selective method for the detection of Ag(+) and Cys is developed with a detection limit of 17 and 280nM, respectively. It is worth noting that the mechanism underlying the increase of the fluorescence of thiazole orange in the presence of i-motif structure is explained. Moreover, a fluorescent DNA logic gate is successfully designed based on the Ag(+)/Cys-mediated reversible fluorescence changes. The proposed detection strategy is label-free and economical. In addition, this system shows a great promise for i-motif/TO complex to analyze Ag(+) in the real samples.
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Affiliation(s)
- Bei Hua Kang
- Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China
| | - Zhong Feng Gao
- Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China
| | - Na Li
- Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China
| | - Yan Shi
- Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China
| | - Nian Bing Li
- Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
| | - Hong Qun Luo
- Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
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12
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Niknezhad Z, Hassani L, Norouzi D. Investigating actinomycin D binding to G-quadruplex, i-motif and double-stranded DNA in 27-nt segment of c-MYC gene promoter. Mater Sci Eng C Mater Biol Appl 2016; 58:1188-93. [PMID: 26478420 DOI: 10.1016/j.msec.2015.09.072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 09/13/2015] [Accepted: 09/18/2015] [Indexed: 01/03/2023]
Abstract
c-MYC DNA is an attractive target for drug design, especially for cancer chemotherapy. Around 90% of c-MYC transcription is controlled by NHE III1, whose 27-nt purine-rich strand has the ability to form G-quadruplex structure. In this investigation, interaction of ActD with 27-nt G-rich strand (G/c-MYC) and its equimolar mixture with the complementary sequence, (GC/c-MYC) as well as related C-rich oligonucleotide (C/c-MYC) was evaluated. Molecular dynamic simulations showed that phenoxazine and lactone rings of ActD come close to the outer G-tetrad nucleotides indicating that ActD binds through end-stacking to the quadruplex DNA. RMSD and RMSF revealed that fluctuation of the quadruplex DNA increases upon interaction with the drug. The results of spectrophotometry and spectrofluorometry indicated that ActD most probably binds to the c-MYC quadruplex and duplex DNA via end-stacking and intercalation, respectively and polarity of ActD environment decreases due to the interaction. It was also found that binding of ActD to the GC-rich DNA is stronger than the two other forms of DNA. Circular dichroism results showed that the type of the three forms of DNA structures doesn't change, but their compactness alters due to their interaction with ActD. Finally, it can be concluded that ActD binds differently to double stranded DNA, quadruplex DNA and i-motif.
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13
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Kikuta K, Piao H, Brazier J, Taniguchi Y, Onizuka K, Nagatsugi F, Sasaki S. Stabilization of the i-motif structure by the intra-strand cross-link formation. Bioorg Med Chem Lett 2015; 25:3307-10. [PMID: 26105193 DOI: 10.1016/j.bmcl.2015.05.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/19/2015] [Accepted: 05/22/2015] [Indexed: 02/06/2023]
Abstract
The i-motif structures are formed by oligonucleotides containing cytosine tracts under acidic conditions. The folding of the i-motif under physiological conditions is of great interest because of its biological role. In this study, we investigated the effect of the intra-strand cross-link on the stability of the i-motif structure. The 4-vinyl-substituted analog of thymidine (T-vinyl) was incorporated into the 5'-end of the human telomere complementary strand, which formed the intra-strand cross-link with the internal adenine. The intra-strand cross-linked i-motif displayed CD spectra similar to that of the natural i-motif at acidic pH, which was transformed into a random coil with the increasing pH. The pH midpoint for the transition from the i-motif to random coil increased from pH 6.1 for the natural one to pH 6.8 for the cross-linked one. The thermodynamic parameters were obtained by measuring the thermal melting behaviors by CD and UV, and it was determined that the intra-strand cross-linked i-motif is stabilized due to a favorable entropy effect. Thus, this study has clearly indicated the validity of the intra-strand cross-linking for stabilization of the i-motif structure.
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Affiliation(s)
- Kenji Kikuta
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Haishun Piao
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - John Brazier
- School of Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, UK
| | - Yosuke Taniguchi
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kazumitsu Onizuka
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Fumi Nagatsugi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shigeki Sasaki
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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14
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Zhao P, Jin SF, Lu JZ, Lv JL, Wu GQ, Chen PP, Tan CL, Chen DW. Novel porphyrin-daunomycin hybrids: synthesis and preferential binding to G-quadruplexes over i-motif. Spectrochim Acta A Mol Biomol Spectrosc 2015; 137:227-235. [PMID: 25222318 DOI: 10.1016/j.saa.2014.08.123] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 08/18/2014] [Accepted: 08/24/2014] [Indexed: 06/03/2023]
Abstract
Encouraged by the enormous importance attributed to the structure and function of human telomeric DNA, herein we focused our attention on the interaction of a serious of newly prepared porphyrin-daunomycin (Por-DNR) hybrids with the guanine-rich single-strand oligomer (G4) and the complementary cytosine-rich strand (i-motif). Various spectral methods such as absorption and fluorescence titration, surface-enhanced Raman and circular dichroism spectrum were integrated in the experiment and it was found that these Por-DNR hybrids could serve as prominent molecules to recognize G4 and i-motif. What is more, interesting results were obtained that the hybrids with longer flexible links are more favorable in binding with both G4 and i-motif than the hybrid with shorter linkage. These Por-DNR hybrids may help to develop new ideas in the research of human telomeric DNA with small molecules.
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Affiliation(s)
- Ping Zhao
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, No. 13, Changmingshui Road, Zhongshan 528458, PR China.
| | - Shu-fang Jin
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, No. 13, Changmingshui Road, Zhongshan 528458, PR China
| | - Jia-Zheng Lu
- School of Pharmacy, Guangdong Pharmaceutical University, No. 280, Waihuandong Road, Education Mega Centre, Guangzhou 510006, PR China.
| | - Jun-liang Lv
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, No. 13, Changmingshui Road, Zhongshan 528458, PR China
| | - Gong-qing Wu
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, No. 13, Changmingshui Road, Zhongshan 528458, PR China
| | - Pan-Pan Chen
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, No. 13, Changmingshui Road, Zhongshan 528458, PR China
| | - Cai-Lian Tan
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, No. 13, Changmingshui Road, Zhongshan 528458, PR China
| | - Dian-Wen Chen
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, No. 13, Changmingshui Road, Zhongshan 528458, PR China
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15
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Day HA, Pavlou P, Waller ZAE. i-Motif DNA: structure, stability and targeting with ligands. Bioorg Med Chem 2014; 22:4407-18. [PMID: 24957878 DOI: 10.1016/j.bmc.2014.05.047] [Citation(s) in RCA: 262] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/09/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
Abstract
i-Motifs are four-stranded DNA secondary structures which can form in sequences rich in cytosine. Stabilised by acidic conditions, they are comprised of two parallel-stranded DNA duplexes held together in an antiparallel orientation by intercalated, cytosine-cytosine(+) base pairs. By virtue of their pH dependent folding, i-motif forming DNA sequences have been used extensively as pH switches for applications in nanotechnology. Initially, i-motifs were thought to be unstable at physiological pH, which precluded substantial biological investigation. However, recent advances have shown that this is not always the case and that i-motif stability is highly dependent on factors such as sequence and environmental conditions. In this review, we discuss some of the different i-motif structures investigated to date and the factors which affect their topology, stability and dynamics. Ligands which can interact with these structures are necessary to aid investigations into the potential biological functions of i-motif DNA and herein we review the existing i-motif ligands and give our perspective on the associated challenges with targeting this structure.
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Affiliation(s)
- Henry A Day
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Pavlos Pavlou
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK
| | - Zoë A E Waller
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK.
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