title: Apoptin enhances radiation-induced cell death in poorly responding head and neck squamous cell carcinoma cells.
abstract: Treatment of head and neck cancers is still rather poor and worldwide new treatment options are sought. Sensitizing radioresistant tumours by combining irradiation with other therapeutics to induce apoptosis are widely investigated. We examined whether chicken anaemia virus-derived apoptin protein would have a beneficial effect on irradiation of radiosensitive SCC61 and radioresistant SQD9 human head and neck squamous carcinoma cell lines. In both cell lines, concurrent exposure to irradiation and apoptin resulted in analysed mitochondrial cytochrome c release and in cleavage of caspase-3, whereas irradiation alone of SQD9 cells under identical conditions did not. Moreover, in comparison with the irradiation, only the synchronized treatment of apoptin and irradiation resulted in increased cell death in especially the radioresistant SQD9 cells, as measured by means of a colony survival assay. Our data reveal that apoptin treatment represents an effective way for enhancing radiotherapy of tumours responding poorly to radiotherapy.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Leiden University Medical Center, Leiden, the Netherlands.
authors.forename: Remilio A L
authors.initials: RA
authors.lastname: Schoop
authors.forename: Elizabeth M E
authors.initials: EM
authors.lastname: Verdegaal
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Baatenburg de Jong
authors.forename: Mathieu H M
authors.initials: MH
authors.lastname: Noteborn
mesh_terms: D036022:Capsid Proteins / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy; D053148:Caspase 3 / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D045304:Cytochromes c / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
chemical_list: D036022:Capsid Proteins; D011838:Radiation-Sensitizing Agents; C091717:VP3 protein, Chicken anemia virus; D045304:Cytochromes c; D053148:Caspase 3