title: Arsenic Trioxide Induces Apoptosis of HL-60 Cells via Activation of Intrinsic Caspase Protease with Mitochondrial Dysfunction.
abstract: OBJECTIVE
  Arsenic trioxide (As2O3) was introduced into the treatment of refractory or relapsed acute promyelocytic leukemia and showed a striking effectiveness in China and United States multicenter study. However, the mechanistic basis for the carcinogenic or therapeutic effects of arsenics is still poorly understood. So, this study is performed to determine whether As2O3 induces apoptosis through intrinsic caspase cascades in acute promyelocytic leukemia HL-60 cells.
  
  
  METHODS
  HL-60 cells were treated with As2O3 to investigate apoptosis through signaling of caspase cascades and mitochondrial dysfunction.
  
  
  RESULTS
  As2O3 (>0.5 uM) decreased the viability of HL-60 cells in a dose-dependent manner, which was revealed as apoptosis shown chromatin condensation and ladder pattern DNA fragmentation. As2O3 increased the catalytic activity of caspase family cysteine proteases including caspase-3 and -9 proteases. Consistently, PARP, an intracellular biosubstrate of caspase-3 protease, was cleaved from 116 kDa to 85 kDa fragments. It also induced the change of mitochondrial membrane potential. Morever, As2O3 resulted in the increase of Bak.
  
  
  CONCLUSIONS
  These data suggest that As2O3 induces apoptosis of HL-60 cells through activation of intrinsic caspase protease with mitochondrial dysfunction.
authors.forename: Byung Hak
authors.initials: BH
authors.lastname: Jung
authors.forename: Channy
authors.initials: C
authors.lastname: Park
authors.forename: Hak Ryul
authors.initials: HR
authors.lastname: Kim
authors.forename: Moo Rim
authors.initials: MR
authors.lastname: Park
keywords: Apoptosis; Arsenic trioxide; Caspase