A platinum(II) phenylphenanthroimidazole with an extended side-chain exhibits slow dissociation from a c-Kit G-quadruplex motif

Chemistry. 2013 Dec 23;19(52):17836-45. doi: 10.1002/chem.201301590. Epub 2013 Nov 18.


A series of three platinum(II) phenanthroimidazoles each containing a protonable side-chain appended from the phenyl moiety through copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) were evaluated for their capacities to bind to human telomere, c-Myc, and c-Kit derived G-quadruplexes. The side-chain has been optimized to enable a multivalent binding mode to G-quadruplex motifs, which would potentially result in selective targeting. Molecular modeling, high-throughput fluorescence intercalator displacement (HT-FID) assays, and surface plasmon resonance (SPR) studies demonstrate that complex 2 exhibits significantly slower dissociation rates compared to platinum phenanthroimidazoles without side-chains and other reported G-quadruplex binders. Complex 2 showed little cytotoxicity in HeLa and A172 cancer cell lines, consistent with the fact that it does not follow a telomere-targeting pathway. Preliminary mRNA analysis shows that 2 specifically interacts with the ckit promoter region. Overall, this study validates 2 as a useful molecular probe for c-Kit related cancer pathways.

Keywords: G-quadruplexes; cancer therapeutic; click chemistry; drug design; platinum(II).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Click Chemistry
  • Drug Design
  • G-Quadruplexes
  • Humans
  • Models, Chemical
  • Models, Molecular
  • Platinum / chemistry*


  • Platinum