The antitumor mechanism of di-2-pyridylketone 2-pyridine carboxylic acid hydrazone and its copper complex in ROS generation and topoisomerase inhibition, and hydrazone involvement in oxygen-catalytic iron mobilization

Int J Oncol. 2015 Nov;47(5):1854-62. doi: 10.3892/ijo.2015.3158. Epub 2015 Sep 11.

Abstract

Iron depletion and stimulation of iron-dependent free radical damage is a rapidly developing field for chelation therapy, but the iron mobilization from ferritin by chelators has received less attention. In this study, the di-2-pyridylketone 2-pyridine carboxylic acid hydrazone (DPPCAH) and its copper complex was prepared and characterized by NMR and MS spectra. The proliferation inhibition assay showed that both DPPCAH and its copper complex exhibited selectively proliferation inhibition for HepG2 (IC50, 4.6 ± 0.2 µM for DPPACH and 1.3 ± 0.2 µM for its copper complex), but less inhibition for HCT-116 cell line (IC50, >100 µM for DPPACH and 7.8 ± 0.4 µM for its copper complex). The mechanistic studies revealed that DPPACH could remove iron from ferritin in a oxygen-catalytic manner, and contributed to redox activity of labile iron pool (LIP), that is less reported for the chelators that possess significant biological activity. The reactive oxygen species (ROS) generation and DNA cleavage assay in vitro and in vivo showed that both DPPACH-Fe(II) and DPPACH-Cu were redox-active species, indicating that ROS may mediate their antitumor activity. Further study revealed that both DPPACH and its copper complex displayed certain degree of inhibition of type II topoisomerase (Top) which contributed to their antitumor activity. Thus, the mechanism that iron mobilization by DPPACH from ferritin contributed to LIP was proposed, and both DPPACH and its copper complex were involved in ROS generation and Top II inhibition for their antitumor activities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Cell Proliferation / drug effects*
  • Copper / chemistry
  • DNA Topoisomerases / drug effects
  • Hep G2 Cells
  • Humans
  • Hydrazones / administration & dosage*
  • Hydrazones / chemistry
  • Iron / chemistry
  • Liver Neoplasms / drug therapy*
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology
  • Oxygen / chemistry
  • Reactive Oxygen Species / metabolism*
  • Topoisomerase Inhibitors / administration & dosage
  • Topoisomerase Inhibitors / chemistry

Substances

  • Hydrazones
  • Reactive Oxygen Species
  • Topoisomerase Inhibitors
  • Copper
  • Iron
  • DNA Topoisomerases
  • Oxygen