Copper (II) and 2,2'-bipyridine complexation improves chemopreventive effects of naringenin against breast tumor cells

PLoS One. 2014 Sep 5;9(9):e107058. doi: 10.1371/journal.pone.0107058. eCollection 2014.

Abstract

Cancer is the second leading cause of death worldwide and there is epidemiological evidence that demonstrates this tendency is emerging. Naringenin (NGEN) is a trihydroxyflavanone that shows various biological effects such as antioxidant, anticancer, anti-inflammatory, and antiviral activities. It belongs to flavanone class, which represents flavonoids with a C6-C3-C6 skeleton. Flavonoids do not exhibit sufficient activity to be used for chemotherapy, however they can be chemically modified by complexation with metals such as copper (Cu) (II) for instance, in order to be applied for adjuvant therapy. This study investigated the effects of Cu(II) and 2,2'-bipyridine complexation with naringenin on MDA-MB-231 cells. We demonstrated that naringenin complexed with Cu(II) and 2,2'-bipyridine (NGENCuB) was more efficient inhibiting colony formation, proliferation and migration of MDA-MB-231 tumor cells, than naringenin (NGEN) itself. Furthermore, we verified that NGENCuB was more effective than NGEN inhibiting pro-MMP9 activity by zymography assays. Finally, through flow cytometry, we showed that NGENCuB is more efficient than NGEN inducing apoptosis in MDA-MB-231 cells. These results were confirmed by gene expression analysis in real time PCR. We observed that NGENCuB upregulated the expression of pro-apoptotic gene caspase-9, but did not change the expression of caspase-8 or anti-apoptotic gene Bcl-2. There are only few works investigating the effects of Cu(II) complexation with naringenin on tumor cells. To the best of our knowledge, this is the first work describing the effects of Cu(II) complexation of a flavonoid on MDA-MB-231 breast tumor cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2,2'-Dipyridyl / chemistry
  • 2,2'-Dipyridyl / pharmacology*
  • 2,2'-Dipyridyl / therapeutic use
  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Antineoplastic Agents, Phytogenic / therapeutic use
  • Breast Neoplasms / pathology
  • Breast Neoplasms / prevention & control*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Chemoprevention
  • Coordination Complexes / pharmacology*
  • Coordination Complexes / therapeutic use
  • Copper / chemistry
  • Copper / pharmacology*
  • Copper / therapeutic use
  • Drug Evaluation, Preclinical
  • Drug Synergism
  • Female
  • Flavanones / pharmacology*
  • Flavanones / therapeutic use
  • Humans

Substances

  • Antineoplastic Agents, Phytogenic
  • Coordination Complexes
  • Flavanones
  • 2,2'-Dipyridyl
  • Copper
  • naringenin

Grants and funding

This work was supported by FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) by the grant number 2008/56758-0 and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.