Disruption of the Keap1/Nrf2-Antioxidant Response System After Chronic Doxorubicin Exposure In Vivo
- PDF / 1,347,138 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 68 Downloads / 129 Views
Disruption of the Keap1/Nrf2‑Antioxidant Response System After Chronic Doxorubicin Exposure In Vivo Kendra K. S. Nordgren1 · Kendall B. Wallace1
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Doxorubicin (DOX) is a widely prescribed anthracycline antineoplastic drug for treating human solid tumors and leukemias. However, DOX therapy is limited by a cumulative, dose-dependent, and irreversible cardiomyopathy that occurs with repeated administration. Presumably, a pivotal initiating event of DOX-induced cardiotoxicity is the production of reactive oxygen species (ROS) and oxidation of lipids, DNA, and proteins. We recently identified activation of the Keap1/Nrf2-antioxidant response system—a major cellular defense mechanism against such oxidative stress—as an important response to acute DOX exposure in vitro. In the present study, we address the hypothesis that dysregulation of this pathway in cardiac tissue is also manifested in vivo following chronic DOX administration. Male, Sprague–Dawley rats received 6 weekly injections of 2 mg/kg (s.c.) DOX or saline followed by a 5-week drug-free period prior to analysis of cardiac tissue transcripts and proteins. In contrast to in vitro findings, the Keap1/Nrf2-antioxidant response system was suppressed in hearts of DOXtreated animals and consistent with the observed decrease in protein abundance for Nrf2 and PGAM5, both of which are substrates for Keap1. Although this shift in Keap1/Nrf2 suppresses the antioxidant pathway, the concurrent loss of PGAM5 could function as a signal for disposal of damaged mitochondria from the cell, thus removing the source of ROS. These findings identify the Keap1/Nrf2 and Keap1/PGAM5 pathways as important responses to DOX-induced cardiac injury in vivo; disruption of this system for mitochondrial hormesis may be an important contributing factor to cardiotoxicity after chronic drug administration. Keywords Doxorubicin · Keap1 · Nrf2 · PGAM5 · PINK1 · Mitophagy
Introduction Doxorubicin (DOX) is one of the most widely used antineoplastic agents in the United States, commonly prescribed for leukemia and breast cancer treatment. DOX also causes cumulative, dose-dependent, and irreversible cardiotoxicity, a side effect that severely limits its clinical utility and often leads to cardiomyopathy (CM) and life-threatening congestive heart failure (CHF) [1–4]. This effect may manifest anytime from shortly after drug therapy to several years later Handling editor: Rajiv Janardhanan. * Kendra K. S. Nordgren [email protected] Kendall B. Wallace [email protected] 1
University of Minnesota Medical School, 1035 University Dr., Duluth, MN 55812, USA
and is a major concern for survivors of childhood cancer chemotherapy [5]. DOX-induced CM and CHF are most often observed in patients receiving a cumulative dose in excess of 550 mg/m2 DOX (~ 15–22 mg/kg, depending on body size) [6]. Unfortunately, due to the cardiovascular complications of treatment, fewer than 50% of these patients survive two years, and for 10% of tho
Data Loading...