Neuronal Nitric Oxide Synthase-Mediated Genotoxicity of 2-Methoxyestradiol in Hippocampal HT22 Cell Line

Mol Neurobiol. 2016 Sep;53(7):5030-40. doi: 10.1007/s12035-015-9434-5. Epub 2015 Sep 17.

Abstract

2-methoxyestradiol, metabolite of 17β-estradiol, is considered a potential anticancer agent, currently investigated in several clinical trials. This natural compound was found to be effective towards great number of cancers, including colon, breast, lung, and osteosarcoma and has been reported to be relatively non-toxic towards non-malignant cells. The aim of the study was to determine the potential neurotoxicity and genotoxicity of 2-methoxyestradiol at physiological and pharmacological relevant concentrations in hippocampal HT22 cell line. Herein, we determined influence of 2-methoxyestradiol on proliferation, inhibition of cell cycle, induction of apoptosis, and DNA damage in the HT22 cells. The study was performed using imaging cytometry and comet assay techniques. Herein, we demonstrated that 2-methoxyestradiol, at pharmacologically and also physiologically relevant concentrations, increases nuclear localization of neuronal nitric oxide synthase. It potentially results in DNA strand breaks and increases in genomic instability in hippocampal HT22 cell line. Thus, we are postulating that naturally occurring 2-methoxyestradiol may be considered a physiological modulator of neuron survival.

Keywords: 2-methoxyestradiol; DNA damage; Hippocampus; Neuronal nitric oxide synthase; Reactive nitrogen species.

MeSH terms

  • 2-Methoxyestradiol
  • Animals
  • Cell Line, Transformed
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • DNA Damage / drug effects
  • DNA Damage / physiology
  • Dose-Response Relationship, Drug
  • Estradiol / analogs & derivatives*
  • Estradiol / toxicity
  • Hippocampus / drug effects*
  • Hippocampus / enzymology*
  • Hippocampus / pathology
  • Mice
  • Nitric Oxide Synthase Type I / biosynthesis*
  • Tubulin Modulators / toxicity

Substances

  • Tubulin Modulators
  • Estradiol
  • 2-Methoxyestradiol
  • Nitric Oxide Synthase Type I
  • Nos1 protein, mouse