title: A novel preclinical strategy for identifying cardiotoxic kinase inhibitors and mechanisms of cardiotoxicity.
abstract: BACKGROUND
  Despite intense interest in strategies to predict which kinase inhibitor (KI) cancer therapeutics may be associated with cardiotoxicity, current approaches are inadequate. Sorafenib is a KI of concern because it inhibits growth factor receptors and Raf-1/B-Raf, kinases that are upstream of extracellular signal-regulated kinases (ERKs) and signal cardiomyocyte survival in the setting of stress.
  
  
  OBJECTIVE
  To explore the potential use of zebrafish as a preclinical model to predict cardiotoxicity and to determine whether sorafenib has associated cardiotoxicity, and, if so, define the mechanisms.
  
  
  RESULTS
  We find that the zebrafish model is readily able to discriminate a KI with little or no cardiotoxicity (gefitinib) from one with demonstrated cardiotoxicity (sunitinib). Sorafenib, like sunitinib, leads to cardiomyocyte apoptosis, a reduction in total myocyte number per heart, contractile dysfunction, and ventricular dilatation in zebrafish. In cultured rat cardiomyocytes, sorafenib induces cell death. This can be rescued by adenovirus-mediated gene transfer of constitutively active MEK1, which restores ERK activity even in the presence of sorafenib. Whereas growth factor-induced activation of ERKs requires Raf, α-adrenergic agonist-induced activation of ERKs does not require it. Consequently, activation of α-adrenergic signaling markedly decreases sorafenib-induced cell death. Consistent with these in vitro data, inhibition of α-adrenergic signaling with the receptor antagonist prazosin worsens sorafenib-induced cardiomyopathy in zebrafish.
  
  
  CONCLUSIONS
  Zebrafish may be a valuable preclinical tool to predict cardiotoxicity. The α-adrenergic signaling pathway is an important modulator of sorafenib cardiotoxicity in vitro and in vivo and appears to act through a here-to-fore unrecognized signaling pathway downstream of α-adrenergic activation that bypasses Raf to activate ERKs.
authors: Center for Translational Medicine, the Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors: Hui
authors: H
authors: Cheng
authors: Gabor
authors: G
authors: Kari
authors: Adam P
authors: AP
authors: Dicker
authors: Ulrich
authors: U
authors: Rodeck
authors: Walter J
authors: WJ
authors: Koch
authors: Thomas
authors: T
authors: Force
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D017209:Apoptosis / Q000187:drug effects*; D001557:Benzenesulfonates / Q000494:pharmacology*; D054715:Cardiotoxins / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors; D005260:Female; D000077156:Gefitinib; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D023421:Models, Animal; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects*; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D048493:Proto-Oncogene Proteins B-raf / Q000037:antagonists & inhibitors; D019908:Proto-Oncogene Proteins c-raf / Q000037:antagonists & inhibitors; D011725:Pyridines / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D000077157:Sorafenib; D000077210:Sunitinib; D015027:Zebrafish
chemical_list: D001557:Benzenesulfonates; D054715:Cardiotoxins; D007211:Indoles; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D011758:Pyrroles; D011799:Quinazolines; D009536:Niacinamide; D000077157:Sorafenib; D048493:Proto-Oncogene Proteins B-raf; D019908:Proto-Oncogene Proteins c-raf; D048049:Extracellular Signal-Regulated MAP Kinases; D000077156:Gefitinib; D000077210:Sunitinib