A novel pharmacological action of ET-1 to prevent the cytotoxicity of doxorubicin in cardiomyocytes

Am J Physiol Regul Integr Comp Physiol. 2001 May;280(5):R1399-406. doi: 10.1152/ajpregu.2001.280.5.R1399.

Abstract

We previously reported that cardiomyocytes produce endothelin (ET)-1 and that the tissue level of ET-1 markedly increased in failing hearts in rats with chronic heart failure. Because the level of plasma ET-1 also increased progressively in patients with breast cancer who received doxorubicin (Dox; Adriamycin), which possesses cardiotoxicity, we hypothesized that ET-1 plays a role in the pathophysiology of cardiomyocytes injured by Dox. In this study, we investigated the effect of ET-1 on the cytotoxicity of Dox in primary cultured neonatal rat cardiomyocytes. The results showed that ET-1 effectively attenuated Dox-induced acute cardiomyocyte cytotoxicity (24-h incubation with Dox) evaluated by in vitro cell toxicity assay [3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay and lactate dehydrogenase release]. The cytoprotective effect of ET-1 was mediated via ET(A) receptors, because pretreatment with the ET(A)-receptor antagonist BQ123 completely suppressed the cytoprotective effect of ET-1, whereas the ET(B)-receptor antagonist BQ788 did not. The cytoprotective effect of ET-1 was abolished by pretreatment with cycloheximide or staurosporine. These results suggest that a protein molecule(s), which is synthesized de novo by the stimulation of protein kinase pathway, is involved in the cytoprotective effect of ET-1. ET-1 increased the expression of an endogenous antioxidant, manganese superoxide dismutase (Mn-SOD), in the cardiomyocytes, as demonstrated by a Western blotting analysis. Pretreatment with an antisense oligodeoxyribonucleotide of Mn-SOD markedly attenuated the cytoprotective effect of ET-1 on the Dox-induced cytotoxicity. However, under conditions of prolonged incubation with Dox (48 h), ET-1 did not affect Dox-induced cardiomyocyte cytotoxicity in culture. These results suggest that ET-1 prevents the early phase of Dox-induced cytotoxicity via the upregulation of the antioxidant Mn-SOD through ET(A) receptors in cultured cardiomyocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Cell Survival / drug effects*
  • Cells, Cultured
  • Doxorubicin / antagonists & inhibitors
  • Doxorubicin / toxicity*
  • Endothelin Receptor Antagonists
  • Endothelin-1 / pharmacology*
  • Enzyme Induction
  • Heart / drug effects
  • Heart Ventricles
  • Isoenzymes / biosynthesis
  • Isoenzymes / genetics
  • Kinetics
  • L-Lactate Dehydrogenase / analysis
  • Myocardium / cytology*
  • Myocardium / pathology
  • Oligodeoxyribonucleotides, Antisense / pharmacology
  • Oligopeptides / pharmacology
  • Peptides, Cyclic / pharmacology
  • Piperidines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, Endothelin A
  • Receptor, Endothelin B
  • Superoxide Dismutase / biosynthesis
  • Superoxide Dismutase / genetics

Substances

  • Endothelin Receptor Antagonists
  • Endothelin-1
  • Isoenzymes
  • Oligodeoxyribonucleotides, Antisense
  • Oligopeptides
  • Peptides, Cyclic
  • Piperidines
  • Receptor, Endothelin A
  • Receptor, Endothelin B
  • BQ 788
  • Doxorubicin
  • L-Lactate Dehydrogenase
  • Superoxide Dismutase
  • cyclo(Trp-Asp-Pro-Val-Leu)