title: Protective effect of survivin in Doxorubicin-induced cell death in h9c2 cardiac myocytes.
abstract: OBJECTIVE
  Apoptosis has been known to be an important mechanism of doxorubicin-induced cardiotoxicity. Survivin, which belongs to the inhibitor of apoptosis protein family, is associated with apoptosis and alteration of the cardiac myocyte molecular pathways. Therefore, we investigated the anti-apoptotic effect and cellular mechanisms of survivin using a protein delivery system in a doxorubicin-induced cardiac myocyte injury model.
  
  
  METHODS
  We constructed a recombinant survivin which was fused to the protein transduction domain derived from HIV-TAT protein. In cultured H9c2 cardiac myocytes, TAT-survivin (1 µM) was added for 1 hour prior to doxorubicin (1 µM) treatment for 24 hours. Cell viability and apoptosis were evaluated by 2-(4,5-dimethyltriazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, caspase-3 activity, and terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling assay. We measured the expression levels of several apoptosis-related signal proteins.
  
  
  RESULTS
  The survivin level was significantly reduced in a dose dependent manner up to 1 µM of doxorubicin in concentration. Purified recombinant TAT-survivin protein was efficiently delivered to H9c2 cardiac myocytes, and its transduction showed an anti-apoptotic effect, demonstrated by reduced caspase-3 activity and the apoptotic index, concomitantly with increased cell viability against doxorubicin injury. The phosphorylation of p38 mitogen-activated protein (MAP) kinase and the release of Smac from mitochondria were suppressed and the expression levels of Bcl-2 and cAMP response element-binding protein (CREB), the transcription factor of Bcl-2, were recovered following TAT-survivin transduction, indicating that survivin had an anti-apoptotic effect against doxorubicin injury.
  
  
  CONCLUSIONS
  Our results suggest that survivin has a potentially cytoprotective effect against doxorubicin-induced cardiac myocyte apoptosis through mechanisms that involve a decrease in the phosphorylation of p38 MAP kinase, mitochondrial Smac release, and increased expression of Bcl-2 and CREB.
authors.affiliation: Graduate Program in Science for Aging, Yonsei University, Seoul, Korea. ; Cardiology Division, Severance Cardiovascular Hospital and Cardiovascular Research Institute, Seoul, Korea.
authors.forename: Beom Seob
authors.initials: BS
authors.lastname: Lee
authors.forename: Soo Hyuk
authors.initials: SH
authors.lastname: Kim
authors.forename: Taewon
authors.initials: T
authors.lastname: Jin
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Jaewon
authors.initials: J
authors.lastname: Oh
authors.forename: Sungha
authors.initials: S
authors.lastname: Park
authors.forename: Sang Hak
authors.initials: SH
authors.lastname: Lee
authors.forename: Ji Hyung
authors.initials: JH
authors.lastname: Chung
authors.forename: Seok-Min
authors.initials: SM
authors.lastname: Kang
keywords: Apoptosis; Doxorubicin; Myocytes, cardiac