A novel preclinical strategy for identifying cardiotoxic kinase inhibitors and mechanisms of cardiotoxicity.
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ABSTRACT: 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.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.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, ?-adrenergic agonist-induced activation of ERKs does not require it. Consequently, activation of ?-adrenergic signaling markedly decreases sorafenib-induced cell death. Consistent with these in vitro data, inhibition of ?-adrenergic signaling with the receptor antagonist prazosin worsens sorafenib-induced cardiomyopathy in zebrafish.Zebrafish may be a valuable preclinical tool to predict cardiotoxicity. The ?-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 ?-adrenergic activation that bypasses Raf to activate ERKs.
SUBMITTER: Cheng H
PROVIDER: S-EPMC3908774 | biostudies-literature | 2011 Dec
REPOSITORIES: biostudies-literature
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