title: Diminished molecular response to doxorubicin and loss of cardioprotective effect of dexrazoxane in Egr-1 deficient female mice.
abstract: Doxorubicin (DOX) and VP16 are DNA topoisomerase II inhibitors yet only DOX induces an irreversible cardiotoxicity, likely through DOX-induced oxidative stress. Egr-1 is overexpressed after many stimuli that increase oxidative stress in vitro and after DOX-injection into adult mice in vivo. To investigate Egr-1 function in the heart, we compared the molecular and histological responses of wild type (+/+) and Egr-1 deficient (-/-) female mice to saline, DOX, VP16, the cardioprotectant dexrazoxane (DZR), or DOX+DZR injection. DOX, and to a lesser extent VP16, induced characteristic increases in cardiac muscle and non-muscle genes typical of cardiac damage in +/+ mice, whereas only beta-MHC and Sp1 were increased in -/- mice. DZR-alone treated +/+ mice showed increased cardiomyocyte transnuclear width without a change to the heart to body weight (HW/BW) ratio. However, DZR-alone treated -/- mice had an increased HW/BW, increased cardiomyocyte transnuclear width, and gene expression changes similar to DOX-injected +/+ mice. DZR pre-injection alleviated DOX-induced gene changes in +/+ mice; in DZR+DOX injected -/- mice the increases in cardiac and non-muscle gene expression were equal to, or exceeded that, detected after DOX-alone or DZR-alone injections. We conclude that Egr-1 is required for DOX-induced molecular changes and for DZR-mediated cardioprotection.
authors: Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, Montréal, QC, Canada.
authors: N
authors: N
authors: Saadane
authors: P
authors: P
authors: Yue
authors: L
authors: L
authors: Alpert
authors: B
authors: B
authors: Mitmaker
authors: G M
authors: GM
authors: Kirby
authors: L E
authors: LE
authors: Chalifour
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D002317:Cardiovascular Agents / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics*; D004317:Doxorubicin / Q000494:pharmacology*; D051766:Early Growth Response Protein 1; D005047:Etoposide / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D017874:Immediate-Early Proteins; D051379:Mice; D010641:Phenotype; D012333:RNA, Messenger / Q000096:biosynthesis; D011929:Razoxane / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000172:deficiency* / Q000235:genetics*
chemical_list: D000903:Antibiotics, Antineoplastic; D002317:Cardiovascular Agents; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D017874:Immediate-Early Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D011929:Razoxane; D005047:Etoposide; D004317:Doxorubicin; D004247:DNA