JBIC Journal of Biological Inorganic Chemistry

, Volume 19, Issue 3, pp 415–426

Investigating the cellular fate of a DNA-targeted platinum-based anticancer agent by orthogonal double-click chemistry

  • Xin Qiao
  • Song Ding
  • Fang Liu
  • Gregory L. Kucera
  • Ulrich Bierbach
Original Paper


Confocal fluorescence microscopy was used to study a platinum-based anticancer agent in intact NCI-H460 lung cancer cells. Orthogonal copper-catalyzed azide–alkyne cycloaddition (click) reactions were used to simultaneously determine the cell-cycle-specific localization of the azide-functionalized platinum–acridine agent 1 and monitor its effects on nucleic acid metabolism. Copper-catalyzed postlabeling showed advantages over copper-free click chemistry using a dibenzocyclooctyne (DIBO)-modified reporter dye, which produced high background levels in microscopic images and failed to efficiently label platinum adducts in chromatin. Compound 1 was successfully labeled with the fluorophore DIBO to yield 1* (characterized by in-line high-performance liquid chromatography/electrospray mass spectrometry). 1 and 1* show a high degree of colocalization in the confocal images, but the ability of 1* to target the (compacted) chromatin was markedly reduced, most likely owing to the steric bulk introduced by the DIBO tag. Nuclear platinum levels correlated inversely with the ability of the cells to synthesize DNA and cause cell cycle arrest, as confirmed by bivariate flow cytometry analysis. In addition, a decrease in the level of cellular transcription, shrinkage of the nucleolar regions, and redistribution of RNA into the cytosol were observed. Postlabeling in conjunction with colocalization experiments is a useful tool for studying the cell killing mechanism of this type of DNA-targeted agent.


Click chemistry Confocal fluorescence microscopy DNA synthesis Platinum agents Transcription 



Copper-catalyzed azide–alkyne cycloaddition








Phosphate-buffered saline

Pol I

RNA polymerase I

Pol II

RNA polymerase II



Supplementary material

775_2013_1086_MOESM1_ESM.pdf (22.2 mb)
Supplementary material 1 (PDF 22,771 kb)

Copyright information

© SBIC 2014

Authors and Affiliations

  • Xin Qiao
    • 1
  • Song Ding
    • 2
  • Fang Liu
    • 2
  • Gregory L. Kucera
    • 3
  • Ulrich Bierbach
    • 2
  1. 1.School of Pharmaceutical SciencesTianjin Medical UniversityTianjinPeople’s Republic of China
  2. 2.Department of ChemistryWake Forest UniversityWinston-SalemUSA
  3. 3.Hematology-Oncology Section, Department of Internal MedicineWake Forest University Health SciencesWinston-SalemUSA

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