Fluorescent light-up acridine orange derivatives bind and stabilize KRAS-22RT G-quadruplex

Janeiro 2018

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.

Autores da comunidade :

• 

  M

  Maria Paula Cordeiro Crespo Cabral Campello Aboim de Barros

  ist25375

  Afiliações e fontes

  IST > DECN

  Departamento de Engenharia e Ciências Nucleares

  IST > C2TN

  Centro de Ciências e Tecnologias Nucleares

  De: orcid

  ID: 57882610

  De: cienciavitae

  ID: 617464

• 

  A

  António Manuel Rocha Paulo

  ist126677

  Afiliações e fontes

  IST > DECN

  Departamento de Engenharia e Ciências Nucleares

  IST > C2TN

  Centro de Ciências e Tecnologias Nucleares

  De: orcid

  ID: 39154395

  De: cienciavitae

  ID: 614507

AO - Versão original do autor

Elsevier

https://www.sciencedirect.com/journal/biochimie

Biochimie

152

144

0300-9084

10.1016/j.biochi.2017.11.004

WOS:000418496400016

chemical-sciences - Química

Palavras-chave

• G-quadruplex
• KRAS promoter
• Acridine orange ligands
• NMR spectroscopy
• Fluorescent probes,

eng - Inglês

http://dx.doi.org/10.1016/j.biochi.2017.11.004