The synergistic effects of rhodamine-123 and merocyanine-540 laser dyes on human tumor cell lines: a new approach to laser phototherapy.
Many new photosensitizers and laser wavelengths are being tested to improve photodynamic therapy by enhancing specific tumor uptake and/or retention, lowering systemic toxicity, and increasing laser tissue penetration. In this study the potential synergistic effects of rhodamine-123 (Rh-123) and merocyanine-540 (MC-540) sensitization of human tumor cell lines after laser exposure were explored. In a first series of experiments, the kinetics of uptake of Rh-123 and M-540 were tested on three human leukemia cell lines (K562, RAJI, 729HF2), P3 squamous carcinoma, and M26 melanoma. Our results demonstrate a clear difference in the rate and amount of uptake of MC-540 (K562 > P3 > RAJI > 729HF2 > M26) and Rh-123 (P3 > RAJI > 729HF2 > K562 > M26) by these cell lines. In a second series of experiments, M26 tumor cells were sensitized with either Rh-123 (1 microgram/ml) or with MC-540 (20 micrograms/ml) alone or with a combination of the two dyes for 60 minutes, then exposed to the argon (514.5 nm) laser at nonthermal energy levels. Our results demonstrate a significant enhancement of the tumoricidal effects of the laser on M26 carcinoma cells after sensitization with both dyes together (MC-540 and Rh-123) when compared to each dye alone. As with combination antibiotherapy, the synergistic effects of two laser dyes that have different intracellular targeting sites appear to enhance tumoricidal effects significantly after exposure to a matching laser wavelength. The data provide evidence for effective laser phototherapy by dye synergy.
Castro
D J
DJ
Division of Otolaryngology-Head and Neck Surgery, UCLA School of Medicine 90024-1624.
Saxton
R E
RE
Haghighat
S
S
Reisler
E
E
Plant
D
D
Soudant
J
J
D000964:Antimetabolites, Antineoplastic / Q000493:pharmacokinetics / Q000627:therapeutic use*; D002051:Burkitt Lymphoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002470:Cell Survival; D004357:Drug Synergism; D005456:Fluorescent Dyes / Q000493:pharmacokinetics / Q000627:therapeutic use*; D006358:Hot Temperature; D006801:Humans; D053685:Laser Therapy; D015448:Leukemia, B-Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D004915:Leukemia, Erythroblastic, Acute / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms; D008545:Melanoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology / Q000556:secondary; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011744:Pyrimidinones / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011829:Radiation Dosage; D020112:Rhodamine 123; D012235:Rhodamines / Q000493:pharmacokinetics / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured
D000964:Antimetabolites, Antineoplastic; D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; D011744:Pyrimidinones; D012235:Rhodamines; D020112:Rhodamine 123; C003954:merocyanine dye