Photodynamic action of merocyanine 540 on artificial and natural cell membranes: involvement of singlet molecular oxygen.

Abstract

The photochemistry of merocyanine 540 (MC 540), a sensitizing dye that binds preferentially to leukemia and electrically excitable cells, has been investigated. MC 540-mediated photooxidation of histidine, arachidonate, and unsaturated phospholipid vesicles was assessed by spin label oximetry and shown to involve type II (singlet oxygen) chemistry. The dye was also shown to be a potent sensitizer of lipid peroxidation in a natural cell membrane, the erythrocyte ghost. Inhibition by azide, stimulation by 2H2O, and identification of the cholesterol product 5 alpha-cholest-6-ene-3 beta,5-diol in this system, all were consistent with singlet oxygen intermediacy. Finally, MC 540 was found to be considerably more phototoxic to K-562 leukemia cells in 2H2O than in H2O. We conclude that singlet oxygen plays a major role in the phototherapeutic effects of this dye.

• Authors: B Kalyanaraman, J B Feix, F Sieber, J P Thomas, A W Girotti
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 84 Issue 9 Pg. 2999-3003 (May 1987) ISSN: 0027-8424 [Print] United States
• PMID: 3033673 (Publication Type: Journal Article, 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

• Fluorescent Dyes
• Liposomes
• Phosphatidylcholines
• Pyrimidinones
• Singlet Oxygen
• merocyanine dye
• Oxygen
• 1-palmitoyl-2-oleoylphosphatidylcholine
• Dimyristoylphosphatidylcholine

Topics

• Cell Line
• Cell Membrane (drug effects, metabolism)
• Dimyristoylphosphatidylcholine
• Electron Spin Resonance Spectroscopy
• Erythrocyte Membrane (drug effects, metabolism)
• Fluorescent Dyes
• Humans
• Leukemia, Myeloid
• Liposomes
• Oxygen
• Phosphatidylcholines
• Photochemistry
• Pyrimidinones (pharmacology)
• Singlet Oxygen