title: Invention of a novel photodynamic therapy for tumors using a photosensitizing PI3K inhibitor.
abstract: XL147 (SAR245408, pilaralisib), an ATP-competitive pan-class I phosphoinositide 3-kinase (PI3K) inhibitor, is a promising new anticancer drug. We examined the effect of the PI3K inhibitor on PC3 prostate cancer cells under a fluorescence microscope and found that XL147-treated cancer cells are rapidly injured by blue wavelength (430 nm) light irradiation. During the irradiation, the cancer cells treated with 0.2-2 μM XL147 showed cell surface blebbing and cytoplasmic vacuolation and died within 15 min. The extent of cell injury/death was dependent on the dose of XL147 and the light power of the irradiation. These findings suggest that XL147 might act as a photosensitizing reagent in photodynamic therapy (PDT) for cancer. Moreover, the cytotoxic effect of photosensitized XL147 was reduced by pretreatment with other ATP-competitive PI3K inhibitors such as LY294002, suggesting that the cytotoxic effect of photosensitized XL147 is facilitated by binding to PI3K in cells. In a single-cell illumination analysis using a fluorescent probe to identify reactive oxygen species (ROS), significantly increased ROS production was observed in the XL147-treated cells when the cell was illuminated with blue light. Taken together, it is conceivable that XL147, which is preferentially accumulated in cancer cells, could be photosensitized by blue light to produce ROS to kill cancer cells. This study will open up new possibilities for PDT using anticancer drugs.
authors.affiliation: Department of Urology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Hayashida
authors.affiliation: Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Ikeda
authors.affiliation: Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Sawada
authors.affiliation: Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Kawai
authors.affiliation: Department of Urology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Kato
authors.affiliation: Department of Urology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kakehi
authors.affiliation: Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa, Japan.
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Araki
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D002867:Chromones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008027:Light; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D051379:Mice; D057054:Molecular Imaging; D009025:Morpholines / Q000494:pharmacology; D009369:Neoplasms / Q000378:metabolism* / Q000628:therapy*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010778:Photochemotherapy / Q000379:methods; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011810:Quinoxalines / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D002867:Chromones; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017319:Photosensitizing Agents; D011810:Quinoxalines; D017382:Reactive Oxygen Species; D013449:Sulfonamides; C581157:XL147; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
keywords: PC3 prostatic cancer cells; PI3K inhibitors; XL147; live-cell imaging; photodynamic therapy; photosensitizer