title: Photosensitizing effects of hypericin on head neck squamous cell carcinoma in vitro.
abstract: Clinical outcome of patients suffering from head neck squamous cell carcinomas is still poor due to recurrent disease and surgical limitations. There is still a demand for multimodality approaches and new therapeutic options. Hypericin is a promising phototoxic drug which was investigated for its effects on head neck squamous cell carcinoma cells in vitro. FaDu cells incubated with or without hypericin were illuminated (450-700 nm, 50,000 lx) for different time periods. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide- and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay were used to score metabolic and apoptotic activity. Even after the shortest illumination FaDu cells incubated with hypericin showed massive reduction of metabolism and excessive apoptosis. This was present even with the lowest hypericin concentration. Cells without hypericin or without illumination were not affected. These photosensitizing effects of hypericin could be suitable for clinical application and could lead to the development of an intraoperative photodynamic therapy of head neck squamous cell carcinomas.
authors.affiliation: Department of Otorhinolaryngology/Head and Neck Surgery, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany, Wiebke.Laffers@gmx.de.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Laffers
authors.forename: Ann-Christin
authors.initials: AC
authors.lastname: Busse
authors.forename: Jens
authors.initials: J
authors.lastname: Mahrt
authors.forename: Phuc
authors.initials: P
authors.lastname: Nguyen
authors.forename: Andreas O H
authors.initials: AO
authors.lastname: Gerstner
authors.forename: Friedrich
authors.initials: F
authors.lastname: Bootz
authors.forename: Johannes T
authors.initials: JT
authors.lastname: Wessels
mesh_terms: D000873:Anthracenes; D017209:Apoptosis / Q000187:drug effects; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D006258:Head and Neck Neoplasms / Q000473:pathology*; D006801:Humans; D020287:In Situ Nick-End Labeling; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D000077195:Squamous Cell Carcinoma of Head and Neck
chemical_list: D000873:Anthracenes; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin