DNA three-way junctions (3WJ) represent one of the simplest supramolecular DNA structures arising as intermediates in homologous recombination in the absence of replication. They are also formed transiently during DNA replication. Here we examine the ability of Fe(II)-based metallohelices to act as DNA 3WJ binders and induce DNA damage in cells. We investigated the interaction of eight pairs of enantiomerically pure Fe(II) metallohelices with four different DNA junctions using biophysical and molecular biology methods. The results show that the metallohelices stabilize all types of tested DNA junctions, with the highest selectivity for the Y-shaped 3WJ and minimal selectivity for the 4WJ. The potential of the best stabilizer of DNA junctions and, at the same time, the most selective 3WJ binder investigated in this work to induce DNA damage was determined in human colon cancer HCT116 cells. These metallohelices proved to be efficient in killing cancer cells and triggering DNA damage that could yield therapeutic benefits.

• MeSH
• DNA * chemie   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• nádory * genetika   MeSH
• poškození DNA MeSH
• železnaté sloučeniny MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Some metallo-supramolecular helical assemblies with size, shape, charge and amphipathic architectures similar to short cationic α-helical peptides have been shown to target and stabilise DNA G-quadruplexes (G4s) in vitro and downregulate the expression of G4-regulated genes in human cells. To expand the library of metallohelical structures that can act as efficient DNA G4 binders and downregulate genes containing G4-forming sequences in their promoter regions, we investigated the interaction of the two enantiomeric pairs of asymmetric Fe(II) triplex metallohelices with a series of five different DNA G4s formed by the human telomeric sequence (hTelo) and in the promoter regions of c-MYC, c-KIT, and k-RAS oncogenes. The metallohelices display preferential binding to G4s over duplex DNA in all investigated G4-forming sequences and induced arrest of DNA polymerase on template strands containing G4-forming sequences. Moreover, the investigated metallohelices suppressed the expression of c-MYC and k-RAS genes at mRNA and protein levels in HCT116 human cancer cells, as revealed by RT-qPCR analysis and western blotting.

• MeSH
• DNA chemie   MeSH
• G-kvadruplexy * MeSH
• lidé MeSH
• nádory * MeSH
• onkogeny MeSH
• promotorové oblasti (genetika) MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The design of efficient and safe gene delivery vehicles remains a major challenge for the application of gene therapy. Of the many reported gene delivery systems, metal complexes with high affinity for nucleic acids are emerging as an attractive option. We have discovered that certain metallohelices-optically pure, self-assembling triple-stranded arrays of fully encapsulated Fe-act as nonviral DNA delivery vectors capable of mediating efficient gene transfection. They induce formation of globular DNA particles which protect the DNA from degradation by various restriction endonucleases, are of suitable size and electrostatic potential for efficient membrane transport and are successfully processed by cells. The activity is highly structure-dependent-compact and shorter metallohelix enantiomers are far less efficient than less compact and longer enantiomers.

• MeSH
• buněčné linie MeSH
• DNA chemie   ultrastruktura   MeSH
• exprese genu MeSH
• fluorescenční protilátková technika MeSH
• genetické vektory * chemie   ultrastruktura   MeSH
• kationty chemie   MeSH
• kovové nanočástice chemie   ultrastruktura   MeSH
• lidé MeSH
• mikroskopie atomárních sil metody   MeSH
• molekulární struktura MeSH
• průtoková cytometrie MeSH
• reportérové geny MeSH
• technika přenosu genů * MeSH
• transfekce MeSH
• viabilita buněk MeSH
• železnaté sloučeniny chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Werner's Complex, as a cationic coordination complex (CCC), has hitherto unappreciated biological properties derived from its binding affinity to highly anionic biomolecules such as glycosaminoglycans (GAGs) and nucleic acids. Competitive inhibitor and spectroscopic assays confirm the high affinity to GAGs heparin, heparan sulfate (HS), and its pentasaccharide mimetic Fondaparinux (FPX). Functional consequences of this affinity include inhibition of FPX cleavage by bacterial heparinase and mammalian heparanase enzymes with inhibition of cellular invasion and migration. Werner's Complex is a very efficient condensing agent for DNA and tRNA. In proof-of-principle for translational implications, it is demonstrated to display antiviral activity against human cytomegalovirus (HCMV) at micromolar concentrations with promising selectivity. Exploitation of non-covalent hydrogen-bonding and electrostatic interactions has motivated the unprecedented discovery of these properties, opening new avenues of research for this iconic compound.

• MeSH
• antivirové látky chemie   farmakologie   MeSH
• Cytomegalovirus účinky léků   MeSH
• fondaparinux antagonisté a inhibitory   MeSH
• glykosaminoglykany chemie   farmakologie   MeSH
• komplexní sloučeniny chemie   farmakologie   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

RNA triplexes are significant tertiary structure motifs that are found in many functional RNAs. Hence, small molecules capable of recognition, binding, and stabilization of the triple-helical RNA structures are emerging as attractive potential molecular biology tools and therapeutic agents. Here, we utilize methods of molecular biology and biophysics to study the interactions of a series of antitumor substitution-inert polynuclear platinum complexes (SI-PPCs) with triple-helical RNA structures. We show that SI-PPCs recognize and stabilize RNA triplexes and inhibit reverse transcription preferentially in the RNA template prone to the triplex formation. These so far unexplored properties of SI-PPCs suggest that the targeting of triple-stranded regions in RNA might contribute to the biological effects of SI-PPCs.

• MeSH
• antitumorózní látky chemie   MeSH
• komplexní sloučeniny chemie   MeSH
• konformace nukleové kyseliny MeSH
• platina chemie   MeSH
• reverzní transkripce účinky léků   MeSH
• RNA chemie   MeSH
• sekvence nukleotidů MeSH
• Publikační typ
• časopisecké články MeSH

RNA G-quadruplexes have been suggested to play key roles in fundamental biological processes and are linked to human diseases. Thus, they also represent good potential therapeutic targets. Here, we describe, using the methods of molecular biophysics, interactions of a series of biologically-active supramolecular cationic metallohelices with human telomeric RNA G-quadruplex. We demonstrate that the investigated metallohelices bind with a high affinity to human telomeric RNA G-quadruplex and that their binding selectivity considerably differs depending on the dimensions and overall shape of the metallohelices. Additionally, the investigated metallohelices inhibit DNA synthesis on the RNA template containing four repeats of the human telomeric sequence by stabilizing the RNA G-quadruplex structure. Collectively, the results of this study suggest that stabilization of RNA sequences capable of G-quadruplex formation by metallohelices investigated in this work might contribute to the mechanism of their biological activity.

• MeSH
• DNA chemie   metabolismus   MeSH
• G-kvadruplexy * MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• RNA chemie   metabolismus   MeSH
• telomery metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The substitution inert platinum agent [Pt(1 S,2 S-diaminocyclohexane)(5,6-dimethyl-1,10-phenanthroline)]2+ (56MeSS, 5) is a potent cytotoxic metallodrug. In contrast to conventional cisplatin or oxaliplatin, the mechanism of action (MoA) of 5 is fundamentally different. However, details of the mechanism by which the 5,6-dimethyl-1,10-phenanthroline ligand contributes to the cytotoxicity of 5 and its derivatives have not been sufficiently clarified so far. Here, we show that 5 and its Pt(IV) derivatives exhibit an intriguing potency in the triple-negative breast cancer cells MDA-MB-231. Moreover, we show that the Pt(IV) derivatives of 5 act by multimodal MoA resulting in the global biological effects, that is, they damage nuclear DNA, reduce the mitochondrial membrane potential, induce the epigenetic processes, and last but not least, the data provide evidence that changes in the organization of cytoskeleton networks are functionally important for 5 and its derivatives, in contrast to clinically used platinum cytostatics, to kill cancer cells.

• MeSH
• aktiny antagonisté a inhibitory   MeSH
• antitumorózní látky chemická syntéza   metabolismus   farmakologie   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• cytoskelet účinky léků   MeSH
• DNA nádorová účinky léků   MeSH
• epigeneze genetická účinky léků   MeSH
• křečci praví MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• ligandy MeSH
• mikrotubuly účinky léků   MeSH
• modulátory tubulinu farmakologie   MeSH
• nádorové buněčné linie MeSH
• organoplatinové sloučeniny chemická syntéza   metabolismus   farmakologie   MeSH
• triple-negativní karcinom prsu farmakoterapie   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The interaction between the HIV-1 transactivator protein Tat and TAR (transactivation responsive region) RNA, plays a critical role in HIV-1 transcription. Iron(II) supramolecular helicates were evaluated for their in vitro activity to inhibit Tat-TAR RNA interaction using UV melting studies, electrophoretic mobility shift assay, and RNase A footprinting. The results demonstrate that iron(II) supramolecular helicates inhibit Tat-TAR interaction at nanomolar concentrations by binding to TAR RNA. These studies provide a new insight into the biological potential of metallosupramolecular helicates.

• MeSH
• genové produkty tat - virus lidské imunodeficience metabolismus   MeSH
• HIV-1 účinky léků   fyziologie   MeSH
• konformace nukleové kyseliny MeSH
• replikace viru účinky léků   MeSH
• RNA virová chemie   metabolismus   MeSH
• vazba proteinů MeSH
• železnaté sloučeniny chemie   farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Trans diiodido platinum(II) complexes bearing the same as well as different aliphatic amines (mixed-amines) have interesting biological activity; cytotoxicity and interactions with some important biological models have already been demonstrated. Herein we described the interaction of such compounds with ct-DNA, supercoiled and linearized plasmid DNA and 5-GMP. Interestingly, UV irradiation of these compounds results in an increase in reactivity towards DNA and 5-GMP in such model systems. Additionally, the cytotoxicity of the trans-Pt(II) complexes towards human cancer cells is noticeably increased when treatment is combined for 90min with UVA-irradiation. With this work we provide evidence that trans diiodido compounds can be activated by UV-light over relatively short treatment times.

• MeSH
• antitumorózní látky chemie   účinky záření   toxicita   MeSH
• DNA chemie   MeSH
• jodidy chemie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• organoplatinové sloučeniny chemie   účinky záření   toxicita   MeSH
• ultrafialové záření * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Loss of a base in DNA leading to creation of an abasic (AP) site leaving a deoxyribose residue in the strand, is a frequent lesion that may occur spontaneously or under the action of various physical and chemical agents. Progress in the understanding of the chemistry and enzymology of abasic DNA largely relies upon the study of AP sites in synthetic duplexes. We report here on interactions of diastereomerically pure metallo-helical 'flexicate' complexes, bimetallic triple-stranded ferro-helicates [Fe2(NN-NN)3](4+) incorporating the common NN-NN bis(bidentate) helicand, with short DNA duplexes containing AP sites in different sequence contexts. The results show that the flexicates bind to AP sites in DNA duplexes in a shape-selective manner. They preferentially bind to AP sites flanked by purines on both sides and their binding is enhanced when a pyrimidine is placed in opposite orientation to the lesion. Notably, the Λ-enantiomer binds to all tested AP sites with higher affinity than the Δ-enantiomer. In addition, the binding of the flexicates to AP sites inhibits the activity of human AP endonuclease 1, which is as a valid anticancer drug target. Hence, this finding indicates the potential of utilizing well-defined metallo-helical complexes for cancer chemotherapy.

• MeSH
• 2-aminopurin analýza   MeSH
• amilorid analýza   MeSH
• antitumorózní látky chemie   MeSH
• denaturace nukleových kyselin MeSH
• DNA footprinting MeSH
• DNA-lyasa (apurinová nebo apyrimidinová) antagonisté a inhibitory   MeSH
• DNA chemie   MeSH
• inhibitory enzymů chemie   MeSH
• kalorimetrie MeSH
• poškození DNA * MeSH
• vazebná místa MeSH
• železnaté sloučeniny chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH