Rapid collapse of mitochondrial transmembrane potential in HL-60 cells and isolated mitochondria treated with anti-tumor 1,4-anthracenediones.

Abstract

Since synthetic analogs of 1,4-anthraquinone (AQ code number), such as AQ8, AQ9 and AQ10, can trigger cytochrome c release without caspase activation and retain their ability to induce apoptosis in multidrug-resistant (MDR) tumor cells, fluorescent probes of transmembrane potential have been used to determine whether these anti-tumor compounds might directly target mitochondria in cell and cell-free systems to cause the collapse of mitochondrial membrane potential (/Deltapsim) that is linked to permeability transition pore (PTP) opening. Using JC-1 dye, the abilities of various AQ analogs to induce the /Deltapsim in wild-type and MDR HL-60 cells are rapid (within 2.5-10 min), irreversible after drug removal, concentration dependent in the 0.256-10 micromol/l range and generally related to their anti-tumor activities in vitro. The /Deltapsim caused by AQ9 and AQ10, which are more potent than mitoxantrone, staurosporine and the reference depolarizing agent carbonyl cyanide m-chlorophenylhydrazone (CCCP) in HL-60 cells, are not prevented by caspase-2 or -8 inhibitors, suggesting that activations of these apical caspases upstream of mitochondria are not involved in this process. Antitumor AQ analogs (0.256-10 micromol/l) also mimic the abilities of the known depolarizing agents CCCP, alamethicin, gramicidin A and 100 micromol/l CaCl2 to directly induce within 15 min the /Deltapsim in isolated mitochondria prepared from mouse liver and loaded with rhodamine 123 dye. The fact that 20 micromol/l Ca2+, which is insufficient to trigger depolarization on its own, is required to reveal the depolarizing effect of AQ9 in isolated mitochondria suggests that anti-tumor AQ analogs might interact with the PTP to alter its conformation and increase its Ca2+ sensitivity. Indeed, such Ca2+-dependent /Deltapsim of isolated mitochondria treated with 1.6 micromol/l AQ9 or 100 micromol/l Ca2+ are blocked by ruthenium red. Daunorubicin (DAU) is unable to mimic the rapid /Deltapsim caused by anti-tumor AQ analogs within 2.5-40 min of treatment in HL-60 cells or isolated mitochondria. Moreover, the /Deltapsim caused by 1.6 micromol/l AQ9 or 100 micromol/l Ca2+ in isolated mitochondria are similarly blocked by cyclosporin A (CsA), bongkrekic acid and decylubiquinone, which prevent PTP opening, suggesting that, in contrast to DAU, anti-tumor AQ analogs that directly target mitochondria to trigger the Ca2+-dependent and CsA-sensitive /Deltapsim, might induce PTP opening and the mitochondrial pathway of apoptosis even in the absence of nuclear signals.

• Authors: Yang Wang, Elisabeth M Perchellet, Mary M Ward, Kaiyan Lou, Duy H Hua, Jean-Pierre H Perchellet
• Journal: Anti-cancer drugs (Anticancer Drugs) Vol. 16 Issue 9 Pg. 953-67 (Oct 2005) ISSN: 0959-4973 [Print] England
• PMID: 16162972 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• ATP Binding Cassette Transporter, Subfamily B, Member 1
• Anthraquinones
• Cysteine Proteinase Inhibitors
• Ion Channels
• Mitochondrial Membrane Transport Proteins
• Mitochondrial Permeability Transition Pore
• Bongkrekic Acid
• Ruthenium Red
• Ubiquinone
• Gramicidin
• Alamethicin
• 2,3-dimethoxy-5-methyl-6-decyl-1,4-benzoquinone
• Carbonyl Cyanide m-Chlorophenyl Hydrazone
• 1,4-anthraquinone
• Cyclosporine
• Mitoxantrone
• Staurosporine
• Calcium Chloride
• Daunorubicin

Topics

• ATP Binding Cassette Transporter, Subfamily B, Member 1 (genetics)
• Alamethicin (pharmacology)
• Animals
• Anthraquinones (chemistry, pharmacology)
• Bongkrekic Acid (pharmacology)
• Calcium Chloride (pharmacology)
• Carbonyl Cyanide m-Chlorophenyl Hydrazone (pharmacology)
• Cyclosporine (pharmacology)
• Cysteine Proteinase Inhibitors (pharmacology)
• Daunorubicin (pharmacology)
• Dose-Response Relationship, Drug
• Drug Resistance, Multiple (genetics)
• Female
• Gramicidin (pharmacology)
• HL-60 Cells
• Humans
• Intracellular Membranes (drug effects, physiology)
• Ion Channels (antagonists & inhibitors, drug effects)
• Membrane Potentials (drug effects)
• Mice
• Mitochondria (drug effects, physiology)
• Mitochondrial Membrane Transport Proteins
• Mitochondrial Permeability Transition Pore
• Mitoxantrone (pharmacology)
• Ruthenium Red (pharmacology)
• Staurosporine (pharmacology)
• Ubiquinone (analogs & derivatives, pharmacology)