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Kaurene diterpene induces apoptosis in human leukemia cells partly through a caspase-8-dependent pathway

Masuo Kondoh1, Ikue Suzuki, Masao Sato

  • 1Department of Pharmaceutics and Biopharmaceutics, Showa Pharmaceutical University, Machida, Tokyo, 194-8543, Japan. masuo@ac.shoyaku.ac.jp

The Journal of Pharmacology and Experimental Therapeutics
|May 27, 2004
PubMed

Insights

Ent-11alpha-hydroxy-16-kauren-15-one (KD) induces apoptosis in leukemia cells by activating caspase-8. This compound shows promise as a cytotoxic agent, potentially overcoming drug resistance in cancer therapy.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cancer Research

Background:

  • Defects in apoptosis pathways drive cancer development and chemotherapy resistance.
  • Identifying agents that restore apoptosis in tumor cells is crucial for effective cancer treatment.

Purpose of the Study:

  • To investigate the mechanism of apoptosis induction by Ent-11alpha-hydroxy-16-kauren-15-one (KD) in human promyelocytic leukemia HL-60 cells.
  • To determine the role of caspase-8 in KD-induced apoptosis and its potential to overcome drug resistance.

Main Methods:

  • Treatment of HL-60 cells with KD.
  • Assessing apoptosis induction and caspase activation (caspase-8 and -9).
  • Utilizing caspase inhibitors and expressing catalytically inactive caspase-8.
  • Analyzing Bid cleavage and procaspase-8 processing.
  • Evaluating the effect of Bcl-2 overexpression on KD-induced cytotoxicity.

Main Results:

  • KD treatment activated both caspase-8 and -9.
  • A caspase-8 specific inhibitor, but not a caspase-9 inhibitor, attenuated KD-induced apoptosis.
  • KD induced time-dependent Bid cleavage and procaspase-8 processing, confirming caspase-8 dependency.
  • Overexpression of Bcl-2 did not confer resistance to KD, indicating its efficacy against drug-resistant factors.

Conclusions:

  • KD induces apoptosis in HL-60 cells via a caspase-8-dependent pathway.
  • KD demonstrates potential as a novel cytotoxic agent for overcoming cancer drug resistance.
  • Further research into KD could lead to new therapeutic strategies for chemoresistant cancers.

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