A lipophilic free radical initiator, 2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN) enhances caspase-dependent apoptosis induced by hyperthermia.

Abstract

PURPOSE:

A free radical initiator, 2,2'-azobis (2-amidinopropane) dehydrochloride (AAPH), was previously found to enhance apoptosis by hyperthermia. Here, but more lipophilic free radical initiator, 2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN) was investigated for its effects as a possible heat sensitizer.

MATERIALS AND METHODS:

Human myelogenous monocytic leukaemia U937 cells were treated with hyperthermia combined with a various concentration of AMVN for investigating its ability to induce apoptosis and various parameters to identify the pathway.

RESULTS:

Combined treatment of hyperthermia and AMVN induced DNA fragmentation markedly, while hyperthermia or AMVN alone induced marginal DNA fragmentation. Fractions of cells showed low mitochondrial membrane potential and increased superoxide production after the combined treatment. Experiments using various caspase inhibitors and a fluorogenic monitor of caspase 3 activities indicated that caspase acts both up- and down-stream of mitochondria.

CONCLUSIONS:

AMVN is suggested to be a potential heat sensitizer effective at a lower concentration than AAPH. The possible mechanism is discussed.

• Authors: F-J Li, T Kondo, Q-L Zhao, Y Hayashi, R Ogawa, Z-G Cui, L B Feril Jr
• Journal: International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group (Int J Hyperthermia) 2003 Mar-Apr Vol. 19 Issue 2 Pg. 165-77 ISSN: 0265-6736 [Print] England
• PMID: 12623639 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Azo Compounds
• Caspase Inhibitors
• Free Radicals
• Nitriles
• Reactive Oxygen Species
• 2,2'-azobis(2,4-dimethylvaleronitrile)
• Caspases

Topics

• Apoptosis (drug effects, physiology)
• Azo Compounds (pharmacology)
• Caspase Inhibitors
• Caspases (biosynthesis, physiology)
• Electron Spin Resonance Spectroscopy
• Enzyme Induction
• Free Radicals
• Humans
• Hyperthermia, Induced
• Nitriles (pharmacology)
• Reactive Oxygen Species
• U937 Cells