title: Novel photodynamic therapy using water-dispersed TiO2-polyethylene glycol compound: evaluation of antitumor effect on glioma cells and spheroids in vitro.
abstract: Titanium dioxide (TiO(2)) is thought to be a photocatalytic agent excited by UV light. Our aim was to investigate the photocatalytic antitumor effect of water-dispersed TiO(2) nanoparticles on C6 rat glioma cells and to evaluate the treatment responses by the spheroid models. Water-dispersed TiO(2) nanoparticles were constructed by the adsorption of chemical modified polyethylene glycol (PEG) on the TiO(2) surface (TiO(2)/PEG). Each monolayer and spheroid of C6 cells was coincubated with various concentrations of TiO(2)/PEG and subsequently irradiated with UV light. Damage of the cells and spheroids was evaluated sequentially by staining with the fluorescent dyes. The cytotoxic effect was correlated with the concentration of TiO(2)/PEG and the energy dose of UV irradiation. More than 90% of cells were killed after 13.5 J cm(-2) of UV irradiation in the presence of 500 microg mL(-1) TiO(2)/PEG. The irradiated spheroids in the presence of TiO(2)/PEG showed growth suppression compared with control groups. In TiO(2)/PEG-treated spheroids, the number of Annexin V-FITC-stained cells gradually increased during the first 6 h, and subsequently propidium iodide-stained cells appeared. The results of this study suggest that newly developed photoexcited TiO(2)/PEG have antitumoral activity. Photodynamic therapy utilizing this material can be a clue to a novel therapeutic strategy for glioma.
authors.affiliation: Department of Neurosurgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Takuhito
authors.initials: T
authors.lastname: Narita
authors.forename: Koki
authors.initials: K
authors.lastname: Kanehira
authors.forename: Shuji
authors.initials: S
authors.lastname: Sonezaki
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Kubota
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Terasaka
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Iwasaki
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D005910:Glioma / Q000188:drug therapy*; D053758:Nanoparticles / Q000737:chemistry; D010778:Photochemotherapy / Q000379:methods*; D011092:Polyethylene Glycols / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D018874:Spheroids, Cellular / Q000187:drug effects* / Q000528:radiation effects; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology*; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; D014867:Water; C009495:titanium dioxide; D011092:Polyethylene Glycols; D014025:Titanium