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  • 1.
    Berner, Andreas
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Das, Rabindra Nath
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bhuma, Naresh
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Golebiewska, Justyna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Abrahamsson, Alva
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andréasson, Måns
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chaudhari, Namrata
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Doimo, Mara
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Bose, Partha Pratim
    Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Huddinge, Sweden.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Strömberg, Roger
    Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Huddinge, Sweden.
    Wanrooij, Sjoerd
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    G4-ligand-conjugated oligonucleotides mediate selective binding and stabilization of individual G4 DNA structures2023In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 146, no 10, p. 6926-6935Article in journal (Refereed)
    Abstract [en]

    G-quadruplex (G4) DNA structures are prevalent secondary DNA structures implicated in fundamental cellular functions, such as replication and transcription. Furthermore, G4 structures are directly correlated to human diseases such as cancer and have been highlighted as promising therapeutic targets for their ability to regulate disease-causing genes, e.g., oncogenes. Small molecules that bind and stabilize these structures are thus valuable from a therapeutic perspective and helpful in studying the biological functions of the G4 structures. However, there are hundreds of thousands of G4 DNA motifs in the human genome, and a long-standing problem in the field is how to achieve specificity among these different G4 structures. Here, we developed a strategy to selectively target an individual G4 DNA structure. The strategy is based on a ligand that binds and stabilizes G4s without selectivity, conjugated to a guide oligonucleotide, that specifically directs the G4-Ligand-conjugated oligo (GL-O) to the single target G4 structure. By employing various biophysical and biochemical techniques, we show that the developed method enables the targeting of a unique, specific G4 structure without impacting other off-target G4 formations. Considering the vast amount of G4s in the human genome, this represents a promising strategy to study the presence and functions of individual G4s but may also hold potential as a future therapeutic modality.

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  • 2.
    Bhuma, Naresh
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Medicinal Chemistry, Uppsala University, BMC, Uppsala, Sweden.
    Andréasson, Måns
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mason, James E.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Das, Rabindra Nath
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India.
    Patel, Ankit Kumat
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Öhlund, Daniel
    Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    The effect of side chain variations on quinazoline-pyrimidine G-quadruplex DNA ligands2023In: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 248, article id 115103Article in journal (Refereed)
    Abstract [en]

    G-quadruplex (G4) DNA structures are involved in central biological processes such as DNA replication and transcription. These DNA structures are enriched in promotor regions of oncogenes and are thus promising as novel gene silencing therapeutic targets that can be used to regulate expression of oncoproteins and in particular those that has proven hard to drug with conventional strategies. G4 DNA structures in general have a well-defined and hydrophobic binding area that also is very flat and featureless and there are ample examples of G4 ligands but their further progression towards drug development is limited. In this study, we use synthetic organic chemistry to equip a drug-like and low molecular weight central fragment with different side chains and evaluate how this affect the compound's selectivity and ability to bind and stabilize G4 DNA. Furthermore, we study the binding interactions of the compounds and connect the experimental observations with the compound's structural conformations and electrostatic potentials to understand the basis for the observed improvements. Finally, we evaluate the top candidates' ability to selectively reduce cancer cell growth in a 3D co-culture model of pancreatic cancer which show that this is a powerful approach to generate highly active and selective low molecular weight G4 ligands with a promising therapeutic window.

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  • 3.
    Deiana, Marco
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Parallel G-quadruplex DNA structures from nuclear and mitochondrial genomes trigger emission enhancement in a nonfluorescent nano-aggregated fluorine-boron-based dye2023In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 14, no 7, p. 1862-1869Article in journal (Refereed)
    Abstract [en]

    Molecular self-assembly is a powerful tool for the development of functional nanostructures with adaptive optical properties. However, in aqueous solution, the hydrophobic effects in the monomeric units often afford supramolecular architectures with typical side-by-side π-stacking arrangement with compromised emissive properties. Here, we report on the role of parallel DNA guanine quadruplexes (G4s) as supramolecular disaggregating-capture systems capable of coordinating a zwitterionic fluorine-boron-based dye and promoting activation of its fluorescence signal. The dye's high binding affinity for parallel G4s compared to nonparallel topologies leads to a selective disassembly of the dye's supramolecular state upon contact with parallel G4s. This results in a strong and selective disaggregation-induced emission that signals the presence of parallel G4s observable by the naked eye and inside cells. The molecular recognition strategy reported here will be useful for a multitude of affinity-based applications with potential in sensing and imaging systems.

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  • 4.
    Deiana, Marco
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jamroskovic, Jan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Das, Rabindra Nath
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Obi, Ikenna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    A Site-Specific Self-Assembled Light-up Rotor Probe for Selective Recognition and Stabilization of c-MYC G-Quadruplex DNA2020In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 12, no 24, p. 12950-12957Article in journal (Refereed)
    Abstract [en]

    Direct and unambiguous evidence of the formation of G-quadruplexes (G4s) in human cells have shown their implication in several key biological events and has emphasized their role as important targets for small-molecule cancer therapeutics. Here, we report on the first example of a self-assembled multitasking molecular-rotor G4-binder able to discriminate between an extensive panel of G4 and non-G4 structures and to selectively light-up (up to 105-fold), bind (nanomolar range), and stabilize the c-MYC promoter G4 DNA. In particular, association with the c-MYC G4 triggers the disassembly of its supramolecular state (disaggregation-induced emission, DIE) and induces geometrical restrictions (motion-induced change in emission, MICE) leading to a significant enhancement of its emission yield. Moreover, this optical reporter is able to selectively stabilize the c-MYC G4 and inhibit DNA synthesis. Finally, by using confocal laser-scanning microscopy (CLSM) we show the ability of this compound to localize primarily in the subnuclear G4-rich compartments of cancer cells. This work provides a benchmark for the future design and development of a new generation of smart sequence-selective supramolecular G4-binders that combine outstanding sensing and stability properties, to be utilized in anti-cancer therapy.

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  • 5.
    Deiana, Marco
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jamroskovic, Jan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Obi, Ikenna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    A Light‐up Logic Platform for Selective Recognition of Parallel G‐Quadruplex Structures via Disaggregation‐Induced Emission2020In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 59, no 2, p. 896-902Article in journal (Refereed)
    Abstract [en]

    The design of turn‐on dyes with optical signals sensitive to the formation of supramolecular structures provides fascinating and underexplored opportunities for G‐quadruplex (G4) DNA detection and characterization. Here, we show a new switching mechanism that relies on the recognition‐driven disaggregation (on‐signal) of an ultrabright coumarin‐quinazoline conjugate. The synthesized probe selectively lights‐up parallel G4 DNA structures via the disassembly of its supramolecular state, demonstrating outputs that are easily integrable into a label free molecular logic system. Finally, our molecule preferentially stains the G4‐rich nucleoli of cancer cells.

  • 6.
    Deiana, Marco
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Obi, Ikenna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Andréasson, Måns
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tamilselvi, Shanmugam
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    A Minimalistic Coumarin Turn-On Probe for Selective Recognition of Parallel G-Quadruplex DNA Structures2021In: ACS Chemical Biology, ISSN 1554-8929, E-ISSN 1554-8937, Vol. 16, no 8, p. 1365-1376Article in journal (Refereed)
    Abstract [en]

    G-quadruplex (G4) DNA structures are widespread in the human genome and are implicated in biologically important processes such as telomere maintenance, gene regulation, and DNA replication. Guanine-rich sequences with potential to form G4 structures are prevalent in the promoter regions of oncogenes, and G4 sites are now considered as attractive targets for anticancer therapies. However, there are very few reports of small “druglike” optical G4 reporters that are easily accessible through one-step synthesis and that are capable of discriminating between different G4 topologies. Here, we present a small water-soluble light-up fluorescent probe that features a minimalistic amidinocoumarin-based molecular scaffold that selectively targets parallel G4 structures over antiparallel and non-G4 structures. We showed that this biocompatible ligand is able to selectively stabilize the G4 template resulting in slower DNA synthesis. By tracking individual DNA molecules, we demonstrated that the G4-stabilizing ligand perturbs DNA replication in cancer cells, resulting in decreased cell viability. Moreover, the fast-cellular entry of the probe enabled detection of nucleolar G4 structures in living cells. Finally, insights gained from the structure–activity relationships of the probe suggest the basis for the recognition of parallel G4s, opening up new avenues for the design of new biocompatible G4-specific small molecules for G4-driven theranostic applications.

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  • 7. Hiremathad, Asha
    et al.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Keri, Rangappa S.
    Development of coumarin-benzofuran hybrids as versatile multitargeted compounds for the treatment of Alzheimer's Disease2018In: Chemical Biology and Drug Design, ISSN 1747-0277, E-ISSN 1747-0285, Vol. 92, no 2, p. 1497-1503Article in journal (Refereed)
    Abstract [en]

    Alzheimer's disease (AD), the most common cause of dementia, is a neurodegenerative disorder characterized by progressive deterioration of memory and cognition. The evidenced multifactorial nature of AD has been considered the main reason for the absence of cure so far. Therefore, the development of novel hybrids to treat the disease is very much essential. Focusing on this, a novel series of coumarin-benzofuran hybrids have been designed and screened as anti-Alzheimer's disease agents. The strategy is to obtain an effective mimetic of donepezil, which is acetylcholinesterase inhibitor. Herein, the two main scaffolds namely coumarin and benzofuran are known pharmacophore moieties and we have performed their molecular design, pharmacokinetic descriptor studies for drug-likeliness. Further, in vitro studies such as antioxidant capacity, acetylcholinesterase (AChE) inhibition and amyloid-beta (A beta) self-aggregation inhibition have also been performed. Most importantly, these studies revealed that the newly synthesized hybrids can be versatile and promising drug-like moieties as efficient anti-AD agents.

  • 8.
    Jamroskovic, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Doimo, Mara
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Obi, Ikenna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kumar, Rajendra
    Umeå University, Faculty of Science and Technology, Department of Physics. Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Brännström, Kristoffer
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Das, Rabindra Nath
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Akhunzianov, Almaz
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan 420008, Russia.
    Deiana, Marco
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Kasho, Kazutoshi
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sulis Sato, Sebastian
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Pourbozorgi-Langroudi, Parham
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Mason, James E.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Medini, Paolo
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Öhlund, Daniel
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Wanrooij, Sjoerd
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Quinazoline Ligands Induce Cancer Cell Death through Selective STAT3 Inhibition and G-Quadruplex Stabilization2020In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 142, no 6, p. 2876-2888Article in journal (Refereed)
    Abstract [en]

    The signal transducer and activator of transcription 3 (STAT3) protein is a master regulator of most key hallmarks and enablers of cancer, including cell proliferation and the response to DNA damage. G-Quadruplex (G4) structures are four-stranded noncanonical DNA structures enriched at telomeres and oncogenes' promoters. In cancer cells, stabilization of G4 DNAs leads to replication stress and DNA damage accumulation and is therefore considered a promising target for oncotherapy. Here, we designed and synthesized novel quinazoline-based compounds that simultaneously and selectively affect these two well-recognized cancer targets, G4 DNA structures and the STAT3 protein. Using a combination of in vitro assays, NMR, and molecular dynamics simulations, we show that these small, uncharged compounds not only bind to the STAT3 protein but also stabilize G4 structures. In human cultured cells, the compounds inhibit phosphorylation-dependent activation of STAT3 without affecting the antiapoptotic factor STAT1 and cause increased formation of G4 structures, as revealed by the use of a G4 DNA-specific antibody. As a result, treated cells show slower DNA replication, DNA damage checkpoint activation, and an increased apoptotic rate. Importantly, cancer cells are more sensitive to these molecules compared to noncancerous cell lines. This is the first report of a promising class of compounds that not only targets the DNA damage cancer response machinery but also simultaneously inhibits the STAT3-induced cancer cell proliferation, demonstrating a novel approach in cancer therapy.

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  • 9.
    Jamroskovic, Jan
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Obi, Ikenna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Movahedi, Anahita
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Identification of putative G-quadruplex DNA structures in S. pombe genome by quantitative PCR stop assay2019In: DNA Repair, ISSN 1568-7864, E-ISSN 1568-7856, Vol. 82, article id 102678Article in journal (Refereed)
    Abstract [en]

    In order to understand in which biological processes the four-stranded G-quadruplex (G4) DNA structures play a role, it is important to determine which predicted regions can actually adopt a G4 structure. Here, to identify DNA regions in Schizosaccharomyces pombe that fold into G4 structures, we first optimized a quantitative PCR (qPCR) assay using the G4 stabilizer, PhenDC3. We call this method the qPCR stop assay, and used it to screen for G4 structures in genomic DNA. The presence of G4 stabilizers inhibited DNA amplification in 14/15 unexplored genomic regions in S. pombe that encompassed predicted G4 structures, suggesting that at these sites the stabilized G4 structure formed an obstacle for the DNA polymerase. Furthermore, the formation of G4 structures was confirmed by complementary in vitro assays. In vivo, the S. pombe G4 unwinder Pif1 helicase, Pfh1, was associated with tested G4 sites, suggesting that the G4 structures also formed in vivo. Thus, we propose that the confirmed G4 structures in S. pombe form an obstacle for replication in vivo, and that the qPCR stop assay is a method that can be used to identify G4 structures. Finally, we suggest that the qPCR stop assay can also be used for identifying G4 structures in other organisms, as well as being adapted to screen for novel G4 stabilizers.

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  • 10. Keri, Rangappa S.
    et al.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Budagumpi, Srinivasa
    Somappa, Sasidhar Balappa
    Patil, Siddappa A.
    Nagaraja, Bhari Mallanna
    An overview of benzo[b]thiophene-based medicinal chemistry2017In: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 138, p. 1002-1033Article, review/survey (Refereed)
    Abstract [en]

    Among sulfur containing heterocycles, benzothiophene and its derivatives are at the focus as these candidates have structural similarities with active compounds to develop new potent lead molecules in drug design. Benzo[b]thiophene scaffold is one of the privileged structures in drug discovery as this core exhibits various biological activities allowing them to act as anti-microbial, anti-cancer, anti-inflammatory, anti-oxidant, anti-tubercular, anti-diabetic, anti-convulsant agents and many more. Further, numerous benzothiophene-based compounds as clinical drugs have been extensively used to treat various types of diseases with high therapeutic potency, which has led to their extensive developments. Due to the wide range of biological activities of benzothiophene, their structure activity relationships (SAR) have generated interest among medicinal chemists, and this has culminated in the discovery of several lead molecules against numerous diseases. The present review is endeavoring to highlight the progress in the various pharmacological activities of benzo[b]thiophene derivatives. It is hoped that this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic benzothiophene-based medicinal drugs, as well as more effective diagnostic agents and pathologic probes. Also, SAR studies that highlight the chemical groups responsible for evoking the potential activities of benzothiophene derivatives are studied and compared.

  • 11.
    Kumar, Rajendra
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bhowmik, Sudipta
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Biophysics, Molecular Biology & Bioinformatics, University of Calcutta, 92, APC Road, Kolkata 700009, India.
    Das, Rabindra Nath
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bhattacharjee, Snehasish
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Subtle structural alterations in G-quadruplex DNA regulate site specificity of fluorescence light-up probes2020In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 48, no 3, p. 1108-1119Article in journal (Refereed)
    Abstract [en]

    G-quadruplex (G4) DNA structures are linked to key biological processes and human diseases. Small molecules that target specific G4 DNA structures and signal their presence would therefore be of great value as chemical research tools with potential to further advance towards diagnostic and therapeutic developments. However, the development of these types of specific compounds remain as a great challenge. In here, we have developed a compound with ability to specifically signal a certain c-MYC G4 DNA structure through a fluorescence light-up mechanism. Despite the compound's two binding sites on the G4 DNA structure, only one of them result in the fluorescence light-up effect. This G-tetrad selectivity proved to originate from a difference in flexibility that affected the binding affinity and tilt the compound out of the planar conformation required for the fluorescence light-up mechanism. The intertwined relation between the presented factors is likely the reason for the lack of examples using rational design to develop compounds with turn-on emission that specifically target certain G4 DNA structures. However, this study shows that it is indeed possible to develop such compounds and present insights into the molecular details of specific G4 DNA recognition and signaling to advance future studies of G4 biology.

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  • 12.
    Kumar, Vipan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Guru Nanak Dev Univ, Punjab, India.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Synthesis of Various N-Substituted 4-Aryloxy/Thiophenoxy/Thioisopropyloxy-Phthalimides2017In: ChemistrySelect, ISSN 2365-6549, Vol. 2, no 11, p. 3293-3296Article in journal (Refereed)
    Abstract [en]

    N-substituted phthalimides have been used to target many biological systems with examples that are clinically used as drugs. Furthermore, N-substituted phthalimides can also be used in other settings such as in the preparation of polymers, as catalysts, and as protective groups. Because of all these important fields of application, the synthesis of phthalimides is well reported. However, synthetic methods to phthalimides with different heteroatom substituents in position 4 are lacking. The present work describes the development of robust synthetic methods to N-substituted 4-aryloxy/thiophenoxy/thioisopropyloxy-phthalimides. The developed methods allow for the introduction of these substituents through an atom efficient one-step synthesis, which gives good to excellent yields and tolerate a wide range of substituents.

  • 13.
    Obi, Ikenna
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Rentoft, Matilda
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Singh, Vandana
    Jamroskovic, Jan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Chand, Karam
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chorell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Westerlund, Fredrik
    Sabouri, Nasim
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Stabilization of G-quadruplex DNA structures in Schizosaccharomyces pombe causes single-strand DNA lesions and impedes DNA replication2020In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 48, no 19, p. 10998-11015Article in journal (Refereed)
    Abstract [en]

    G-quadruplex (G4) structures are stable noncanonical DNA structures that are implicated in the regulation of many cellular pathways. We show here that the G4-stabilizing compound PhenDC3 causes growth defects in Schizosaccharomyces pombe cells, especially during S-phase in synchronized cultures. By visualizing individual DNA molecules, we observed shorter DNA fragments of newly replicated DNA in the PhenDC3-treated cells, suggesting that PhenDC3 impedes replication fork progression. Furthermore, a novel single DNA molecule damage assay revealed increased single-strand DNA lesions in the PhenDC3-treated cells. Moreover, chromatin immunoprecipitation showed enrichment of the leading-strand DNA polymerase at sites of predicted G4 structures, suggesting that these structures impede DNA replication. We tested a subset of these sites and showed that they form G4 structures, that they stall DNA synthesis in vitro and that they can be resolved by the breast cancerassociated Pif1 family helicases. Our results thus suggest that G4 structures occur in S. pombe and that stabilized/unresolved G4 structures are obstacles for the replication machinery. The increased levels of DNA damage might further highlight the association of the human Pif1 helicase with familial breast cancer and the onset of other human diseases connected to unresolved G4 structures.

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