Boswellic acid acetate induces apoptosis through caspase-mediated pathways in myeloid leukemia cells

Mol Cancer Ther. 2005 Mar;4(3):381-8. doi: 10.1158/1535-7163.MCT-03-0266.


The mechanism of the cytotoxic effect of boswellic acid acetate, a 1:1 mixture of alpha-boswellic acid acetate and beta-boswellic acid acetate, isolated from Boswellia carterri Birdw on myeloid leukemia cells was investigated in six human myeloid leukemia cell lines (NB4, SKNO-1, K562, U937, ML-1, and HL-60 cells). Morphologic and DNA fragmentation assays indicated that the cytotoxic effect of boswellic acid acetate was mediated by induction of apoptosis. More than 50% of the cells underwent apoptosis after treatment with 20 mug/mL boswellic acid for 24 hours. This apoptotic process was p53 independent. The levels of apoptosis-related proteins Bcl-2, Bax, and Bcl-XL were not modulated by boswellic acid acetate. Boswellic acid acetate induced Bid cleavage and decreased mitochondrial membrane potential without production of hydrogen peroxide. A general caspase inhibitor (Z-VAD-FMK) and a specific caspase-8 inhibitor II (Z-IETD-FMK) blocked boswellic acid acetate-induced apoptosis. The mRNAs of death receptors 4 and 5 (DR4 and DR5) were induced in leukemia cells undergoing apoptosis after boswellic acid acetate treatment. These data taken together suggest that boswellic acid acetate induces myeloid leukemia cell apoptosis through activation of caspase-8 by induced expression of DR4 and DR5, and that the activated caspase-8 either directly activates caspase-3 by cleavage or indirectly by cleaving Bid, which in turn decreases mitochondria membrane potential.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Chloromethyl Ketones / pharmacology
  • Apoptosis*
  • Blotting, Northern
  • Blotting, Western
  • Caspase 3
  • Caspases / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation
  • DNA Fragmentation
  • HL-60 Cells
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Inhibitory Concentration 50
  • K562 Cells
  • Leukemia, Myeloid / drug therapy*
  • Leukemia, Myeloid / pathology*
  • Membrane Potentials
  • Mitochondria / metabolism
  • Models, Biological
  • Models, Chemical
  • Oligopeptides / pharmacology
  • Protein Binding
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • RNA, Messenger / metabolism
  • Receptors, TNF-Related Apoptosis-Inducing Ligand
  • Receptors, Tumor Necrosis Factor / metabolism
  • Triterpenes / pharmacology*
  • U937 Cells
  • bcl-2-Associated X Protein
  • bcl-X Protein


  • Amino Acid Chloromethyl Ketones
  • BAX protein, human
  • BCL2L1 protein, human
  • Oligopeptides
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • Receptors, TNF-Related Apoptosis-Inducing Ligand
  • Receptors, Tumor Necrosis Factor
  • TNFRSF10A protein, human
  • TNFRSF10B protein, human
  • Triterpenes
  • bcl-2-Associated X Protein
  • bcl-X Protein
  • benzyloxycarbonyl-isoleucyl-glutamyl-threonyl-aspartic acid fluoromethyl ketone
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • boswellic acid
  • Hydrogen Peroxide
  • CASP3 protein, human
  • Caspase 3
  • Caspases