title: Acridine orange excited by low-dose radiation has a strong cytocidal effect on mouse osteosarcoma.
abstract: The study was conducted to clarify the cytocidal effect of combination therapy consisting of administration of acridine orange (AO), which is a photosensitizer, and radiation therapy using in vitro and in vivo mouse osteosarcoma models. The results revealed that AO combined with low-dose X-ray irradiation of about 1-5 Gy had a strong cytocidal effect on the cultured mouse osteosarcoma cells regardless of their chemosensitivity, and that this combination therapy inhibited growth of the in vivo mouse osteosarcoma by induction of tumor necrosis. This effect was inhibited by L-histidine, but not by mannitol. These findings suggested that AO might be excited by X-rays and kill osteosarcoma cells through the release of singlet oxygen, which is toxic to living cells. This mechanism is similar to that of photodynamic therapy with AO.
authors.affiliation: Department of Orthopedic Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Hashiguchi
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kusuzaki
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Murata
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Takeshita
authors.forename: Mitsuoki
authors.initials: M
authors.lastname: Hashiba
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Nishimura
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Ashihara
authors.forename: Yasusuke
authors.initials: Y
authors.lastname: Hirasawa
mesh_terms: D000165:Acridine Orange / Q000009:adverse effects / Q000528:radiation effects* / Q000627:therapeutic use*; D000818:Animals; D048429:Cell Size / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D008175:Lung Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy / Q000556:secondary; D051379:Mice; D008856:Microscopy, Fluorescence; D009368:Neoplasm Transplantation; D012516:Osteosarcoma / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D010778:Photochemotherapy / Q000379:methods*; D015996:Survival Rate; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014965:X-Rays
chemical_list: D000165:Acridine Orange