title: AMP-activated protein kinase α2 and E2F1 transcription factor mediate doxorubicin-induced cytotoxicity by forming a positive signal loop in mouse embryonic fibroblasts and non-carcinoma cells.
abstract: Doxorubicin is one of the most widely used anti-cancer drugs, but its clinical application is compromised by severe adverse effects in different organs including cardiotoxicity. In the present study we explored mechanisms of doxorubicin-induced cytotoxicity by revealing a novel role for the AMP-activated protein kinase α2 (AMPKα2) in mouse embryonic fibroblasts (MEFs). Doxorubicin robustly induced the expression of AMPKα2 in MEFs but slightly reduced AMPKα1 expression. Our data support the previous notion that AMPKα1 harbors survival properties under doxorubicin treatment. In contrast, analyses of Ampkα2(-/-) MEFs, gene knockdown of AMPKα2 by shRNA, and inhibition of AMPKα2 activity with an AMPK inhibitor indicated that AMPKα2 functions as a pro-apoptotic molecule under doxorubicin treatment. Doxorubicin induced AMPKα2 at the transcription level via E2F1, a transcription factor that regulates apoptosis in response to DNA damage. E2F1 directly transactivated the Ampkα2 gene promoter. In turn, AMPKα2 significantly contributed to stabilization and activation of E2F1 by doxorubicin, forming a positive signal amplification loop. AMPKα2 directly interacted with and phosphorylated E2F1. This signal loop was also detected in H9c2, C2C12, and ECV (human epithelial cells) cells as well as mouse liver under doxorubicin treatment. Resveratrol, which has been suggested to attenuate doxorubicin-induced cytotoxicity, significantly blocked induction of AMPKα2 and E2F1 by doxorubicin, leading to protection of these cells. This signal loop appears to be non-carcinoma-specific because AMPKα2 was not induced by doxorubicin in five different tested cancer cell lines. These results suggest that AMPKα2 may serve as a novel target for alleviating the cytotoxicity of doxorubicin.
authors.affiliation: From the Department of Biochemistry and Molecular Biology, Medical Research Center and Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea.
authors.forename: Wookyeom
authors.initials: W
authors.lastname: Yang
authors.forename: In-Ja
authors.initials: IJ
authors.lastname: Park
authors.forename: Hee
authors.initials: H
authors.lastname: Yun
authors.forename: Dong-Uk
authors.initials: DU
authors.lastname: Im
authors.forename: Sangmi
authors.initials: S
authors.lastname: Ock
authors.forename: Jaetaek
authors.initials: J
authors.lastname: Kim
authors.forename: Seon-Mi
authors.initials: SM
authors.lastname: Seo
authors.forename: Ha-Yeon
authors.initials: HY
authors.lastname: Shin
authors.forename: Benoit
authors.initials: B
authors.lastname: Viollet
authors.forename: Insug
authors.initials: I
authors.lastname: Kang
authors.forename: Wonchae
authors.initials: W
authors.lastname: Choe
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Kim
authors.forename: Joohun
authors.initials: J
authors.lastname: Ha
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D019610:Cytoprotection / Q000187:drug effects; D004249:DNA Damage; D004317:Doxorubicin / Q000494:pharmacology*; D050687:E2F1 Transcription Factor / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D051379:Mice; D008954:Models, Biological; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D055550:Protein Stability / Q000187:drug effects; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects*; D013267:Stilbenes / Q000494:pharmacology
chemical_list: D050687:E2F1 Transcription Factor; C493754:E2f1 protein, mouse; D013267:Stilbenes; D004317:Doxorubicin; C534978:Prkaa2 protein, mouse; D055372:AMP-Activated Protein Kinases; D000077185:Resveratrol
keywords: AMP-activated Kinase (AMPK); Anticancer Drug; Cell Death; Doxorubicin; E2F Transcription Factor; Resveratrol