Organoplatinum(II) complexes with nucleobase motifs as inhibitors of human topoisomerase II catalytic activity

Ping Wang, Chung Hang Leung, Edmond Dik Lung MA, Wei Lu, Chi Ming Che*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

37 Citations (Scopus)


Platinum(II) complexes bearing acetylide ligands containing nucleobase motifs are prepared and their impact on human topoisomerase II (TopoII) is evaluated. Both platinum( II) complexes [PtII(C∧N∧N)- (C≡CCH2R)] (1a-c) and [PtII(tBu3terpy) (C≡CCH2R)]+ (2a-c) (C∧N∧N=6-phenyl-2,2′- bipyridyl, tBu3terpy=4,4′,4″-tri-tert-butyl-2,2′: 6′,2″-terpyridyl, and R=(a) adenine, (b) thymine, and (c) 2-amino-6-chloropurine) are stable in aqueous solutions for 48 hours at room temperature. The binding constants (K) for the platinum(II) complexes towards calf thymus DNA are in the order of 105 dm3mol -1 as estimated by using UV/Vis absorption spectroscopy. Of the complexes examined, only complexes 1a-c are found to behave as intercalators. Both complexes 1a-c and 2a-c inhibit TopoII-induced relaxation of supercoiled DNA, while 2c is the most potent TopoII inhibitors among the tested compounds. Inhibition of DNA relaxation is detected at nanomolar concentrations of 2c. All of the platinum(II) complexes are cytotoxic to human cancer cells with IC 50 values of 0.5-13.7 μm, while they are less toxic against normal cells CCD-19 Lu.

Original languageEnglish
Pages (from-to)2271-2280
Number of pages10
JournalChemistry - An Asian Journal
Issue number10
Publication statusPublished - 4 Oct 2010

Scopus Subject Areas

  • Biochemistry
  • Organic Chemistry

User-Defined Keywords

  • Cancer
  • DNA
  • Inhibitors
  • Nucleobases
  • Platinum


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