The G-quadruplex (G4)-forming sequence within the AS1411 derivatives with alternative nucleobases and backbones can improve the chemical and biological properties of AS1411. Zn(II) phthalocyanine (ZnPc) derivatives have potential as high-affinity G4 ligands because they have similar size and shape to the G-quartets. The interactions of four Zn(II) phthalocyanines with the G4 AS1411 aptamer and its derivatives were determined by biophysical techniques, molecular docking and gel electrophoresis. Cell viability assay was carried out to evaluate the antiproliferative effects of Zn(II) phthalocyanines and complexes. CD experiments showed structural changes after addition of ZnPc 4, consistent with multiple binding modes and conformations shown by NMR and gel electrophoresis. CD melting confirmed that ZnPc 2 and ZnPc 4, both containing eight positive charges, are able to stabilize the AT11 G4 structure (ΔTm > 30 °C and 18.5 °C, respectively). Molecular docking studies of ZnPc 3 and ZnPc 4 suggested a preferential binding to the 3'- and 5'-end, respectively, of the AT11 G4. ZnPc 3 and its AT11 and AT11-L0 complexes revealed pronounced cytotoxic effect against cervical cancer cells and no cytotoxicity to normal human cells. Zn(II) phthalocyanines provide the basis for the development of effective therapeutic agents as G4 ligands.

• MeSH
• aptamery nukleotidové chemie   farmakologie   MeSH
• buněčné linie MeSH
• G-kvadruplexy MeSH
• HeLa buňky MeSH
• indoly chemie   farmakologie   MeSH
• lidé MeSH
• nádory farmakoterapie   MeSH
• oligodeoxyribonukleotidy chemie   farmakologie   MeSH
• organokovové sloučeniny chemie   farmakologie   MeSH
• protinádorové látky chemie   farmakologie   MeSH
• simulace molekulového dockingu MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

AS1411 is a G-rich DNA oligonucleotide that functions as an aptamer of the protein nucleolin, found at high levels on the surface of cancer cells but not on the surface of normal cells. Herein, we have studied AS1411 as a supramolecular carrier for the delivery of an acridine-based G-quadruplex ligand, C8, to HeLa cancer cells. Two AS1411 derivatives, LNA-AS1411 and U-AS1411, were also tested, in an attempt to compare AS1411 pharmacological properties. The results showed that AS1411-C8 complexation was made with great binding strength and that it lowered the ligand's cytotoxicity towards non-malignant cells. This effect was suggested to be due to a decreased internalization of the complexed versus free C8 as shown by flow cytometry. The AS1411 derivatives, despite forming a stable complex with C8, lacked the necessary tumour-selective behaviour. The binding of C8 to AS1411 G-quadruplex structure did not negatively affect the recognition of nucleolin by the aptamer. The AS1411-C8 repressed c-MYC expression at the transcriptional level, possibly due to C8 ability to stabilize the c-MYC promoter G-quadruplexes. Overall, this study demonstrates the usefulness of AS1411 as a supramolecular carrier of the G-quadruplex binder C8 and the potential of using its tumour-selective properties for the delivery of ligands for cancer therapy.

• MeSH
• aptamery nukleotidové metabolismus   farmakologie   MeSH
• buněčné linie MeSH
• buňky A549 MeSH
• fibroblasty cytologie   účinky léků   metabolismus   MeSH
• fosfoproteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• G-kvadruplexy * MeSH
• genetická transkripce MeSH
• HeLa buňky MeSH
• lidé MeSH
• ligandy MeSH
• nádorové buněčné linie MeSH
• oligodeoxyribonukleotidy metabolismus   farmakologie   MeSH
• orgánová specificita MeSH
• promotorové oblasti (genetika) MeSH
• proteiny vázající RNA antagonisté a inhibitory   genetika   metabolismus   MeSH
• protinádorové látky metabolismus   farmakologie   MeSH
• protoonkogenní proteiny c-myc genetika   metabolismus   MeSH
• regulace genové exprese u nádorů * MeSH
• technika přenosu genů MeSH
• vazba proteinů MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

• Publikační typ
• tisková chyba MeSH

KRAS is often found mutated in lethal cancers and should be an important target for anticancer drug development. However, no effective inhibitor has been reported so far, prompting the scientific community to describe the RAS proteins as nearly "undruggable". Recent approaches developed to modulate KRAS protein expression comprises the targeting of G-quadruplex (G4) structures formed within the nuclease hypersensitive element of KRAS promoter region, by designing small and specific ligands to stabilize the tertiary fold and reduce gene expression. In this work, we report in vitro and in silico studies of novel acridine orange (AO) derivatives (C3-C8), developed as G4 stabilizing agents. The results show that the ligands bind with high affinity and stabilize KRAS22-RT G4 with modest specificity over duplex DNA. The most promising ligand C8 stabilizes the structure by ≈ 40 °C. Molecular docking using NMR-derived distance restraints reveal atomic details about the ligand structural features in the interaction with KRAS22-RT G4. In vitro studies with HeLa cells show that the ligands are cytotoxic with IC50 values between 0.9 μM and 5.7 μM. Moreover, the ligands tend to localize in the nucleus as shown by confocal fluorescence microscopy. Overall, these results show that the reported AO ligands display favourable properties as G4 ligands and this study provides structural detail for the development of lead KRAS G4 ligands.

• MeSH
• akridinová oranž chemie   metabolismus   farmakologie   MeSH
• biologický transport MeSH
• fluorescenční barviva chemie   metabolismus   farmakologie   MeSH
• G-kvadruplexy účinky léků   MeSH
• HeLa buňky MeSH
• intracelulární prostor metabolismus   MeSH
• lidé MeSH
• ligandy MeSH
• proliferace buněk účinky léků   MeSH
• protoonkogenní proteiny p21(ras) genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

DNA and RNA guanine-rich oligonucleotides can form non-canonical structures called G-quadruplexes or "G4" that are based on the stacking of G-quartets. The role of DNA and RNA G4 is documented in eukaryotic cells and in pathogens such as viruses. Yet, G4 have been identified only in a few RNA viruses, including the Flaviviridae family. In this study, we analysed the last 157 nucleotides at the 3'end of the HCV (-) strand. This sequence is known to be the minimal sequence required for an efficient RNA replication. Using bioinformatics and biophysics, we identified a highly conserved G4-prone sequence located in the stem-loop IIy' of the negative strand. We also showed that the formation of this G-quadruplex inhibits the in vitro RNA synthesis by the RdRp. Furthermore, Phen-DC3, a specific G-quadruplex binder, is able to inhibit HCV viral replication in cells in conditions where no cytotoxicity was measured. Considering that this domain of the negative RNA strand is well conserved among HCV genotypes, G4 ligands could be of interest for new antiviral therapies.

• MeSH
• buněčné linie MeSH
• G-kvadruplexy * MeSH
• Hepacivirus genetika   fyziologie   MeSH
• konzervovaná sekvence MeSH
• lidé MeSH
• replikace viru MeSH
• RNA virová biosyntéza   chemie   genetika   metabolismus   MeSH
• RNA-dependentní RNA-polymerasa metabolismus   MeSH
• sekvence nukleotidů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH