title: KTP laser and neutral red phototherapy of human squamous cell carcinoma.
abstract: Neutral red (NR) is a cationic, nontoxic vital dye employed as a histologic stain for proliferating cells; it has been used clinically for photodynamic treatment of herpes simplex virus lesions. NR is selectively taken up and concentrated by mitotic cells, an important characteristic for more effective antineoplastic agents. In the present study, UCLA-SO-P3 human squamous carcinoma cells displayed minimal toxicity when incubated with up to 50 microg/ml NR in the absence of light. However, cells incubated with greater than 0.5 microg/ml NR followed by exposure to KTP laser light at 532 nm exhibited nearly 100% tumor cell death. The degree of cell toxicity was proportional to NR dose and laser light fluence. This study demonstrates that NR is an excellent cancer cell photosensitizer in vitro, and, after adding additional in vivo preclinical testing, may prove to be a useful agent in photodynamic destruction of head and neck tumors.
authors.affiliation: Division of Head and Neck Surgery, UCLA School of Medicine, Los Angeles, CA 90095-1782, U.S.A.
authors.forename: Q M
authors.initials: QM
authors.lastname: VanderWerf
authors.forename: D J
authors.initials: DJ
authors.lastname: Castro
authors.forename: R D
authors.initials: RD
authors.lastname: Nguyen
authors.forename: M B
authors.initials: MB
authors.lastname: Paiva
authors.forename: K H
authors.initials: KH
authors.lastname: Chao
authors.forename: M E
authors.initials: ME
authors.lastname: Santillanes
authors.forename: R E
authors.initials: RE
authors.lastname: Saxton
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000378:metabolism; D016923:Cell Death; D004396:Coloring Agents; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D005453:Fluorescence; D006258:Head and Neck Neoplasms / Q000188:drug therapy; D006561:Herpes Simplex / Q000188:drug therapy; D006801:Humans; D053685:Laser Therapy; D007834:Lasers / Q000145:classification; D008938:Mitosis; D009499:Neutral Red / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010710:Phosphates; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011829:Radiation Dosage; D014025:Titanium; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D004396:Coloring Agents; D010710:Phosphates; D017319:Photosensitizing Agents; C064806:potassium titanylphosphate; D009499:Neutral Red; D014025:Titanium