title: Testosterone Antagonizes Doxorubicin-Induced Senescence of Cardiomyocytes.
abstract: BACKGROUND
  Chronic cardiotoxicity is less common in male than in female patients receiving doxorubicin and other anthracyclines at puberty and adolescence. We hypothesized that this sex difference might be secondary to distinct activities of sex hormones on cardiomyocyte senescence, which is thought to be central to the development of long-term anthracycline cardiomyopathy.
  
  
  RESULTS
  H9c2 cells and neonatal mouse cardiomyocytes were exposed to doxorubicin with or without prior incubation with testosterone or 17β-estradiol, the main androgen and estrogen, respectively. Testosterone, but not 17β-estradiol, counteracted doxorubicin-elicited senescence. Downregulation of telomere binding factor 2, which has been pinpointed previously as being pivotal to doxorubicin-induced senescence, was also prevented by testosterone, as were p53 phosphorylation and accumulation. Pretreatment with the androgen receptor antagonist flutamide, the phosphatidylinositol 3 kinase inhibitor LY294002, and the nitric oxide synthase inhibitor L-NG-nitroarginine methyl ester abrogated the reduction in senescence and the normalization of telomere binding factor 2 levels attained by testosterone. Consistently, testosterone enhanced the phosphorylation of AKT and nitric oxide synthase 3. In H9c2 cells, doxorubicin-stimulated senescence was still observed up to 21 days after treatment and increased further when cells were rechallenged with doxorubicin 14 days after the first exposure to mimic the schedule of anthracycline-containing chemotherapy. Remarkably, these effects were also inhibited by testosterone.
  
  
  CONCLUSIONS
  Testosterone protects cardiomyocytes against senescence caused by doxorubicin at least in part by modulating telomere binding factor 2 via a pathway involving the androgen receptor, phosphatidylinositol 3 kinase, AKT, and nitric oxide synthase 3. This is a potential mechanism by which pubescent and adolescent boys are less prone to chronic anthracycline cardiotoxicity than girls.
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Paola
authors.initials: P
authors.lastname: Altieri
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Chiara
authors.initials: C
authors.lastname: Barisione
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Edoardo
authors.initials: E
authors.lastname: Lazzarini
authors.affiliation: Laboratory of Cellular Therapies, Department of Internal Medicine, University of Genova, Italy (A.G.).
authors.forename: Anna
authors.initials: A
authors.lastname: Garuti
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Bezante
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Marco
authors.initials: M
authors.lastname: Canepa
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Paolo
authors.initials: P
authors.lastname: Spallarossa
authors.affiliation: Division of Internal Medicine, Department of Translational Medical Sciences, Federico II University, Napoli, Italy (C.G.T.).
authors.forename: Carlo Gabriele
authors.initials: CG
authors.lastname: Tocchetti
authors.affiliation: Regenerative Medicine Laboratory, Department of Experimental Medicine, University of Genova, Italy (S.B.).
authors.forename: Sveva
authors.initials: S
authors.lastname: Bollini
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Claudio
authors.initials: C
authors.lastname: Brunelli
authors.affiliation: Laboratory of Cardiovascular Biology, Department of Internal Medicine, University of Genova, Italy (P.A., C.B., E.L., G.P.B., M.C., P.S., C.B., P.A.).
authors.forename: Pietro
authors.initials: P
authors.lastname: Ameri
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000903:Antibiotics, Antineoplastic / Q000633:toxicity*; D009202:Cardiomyopathies / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D066126:Cardiotoxicity; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D016922:Cellular Senescence / Q000187:drug effects*; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000633:toxicity*; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D008297:Male; D008810:Mice, Inbred C57BL; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000473:pathology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D011944:Receptors, Androgen / Q000187:drug effects / Q000378:metabolism; D012737:Sex Factors; D015398:Signal Transduction / Q000187:drug effects; D035341:Telomeric Repeat Binding Protein 2 / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*; D013997:Time Factors
chemical_list: C000607144:AR protein, mouse; D000903:Antibiotics, Antineoplastic; D011944:Receptors, Androgen; D035341:Telomeric Repeat Binding Protein 2; D013739:Testosterone; D004958:Estradiol; D004317:Doxorubicin; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; C496316:Nos3 protein, rat; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt
keywords: cardiotoxicity; doxorubicin; senescence; sex; testosterone