title: A next-generation bifunctional photosensitizer with improved water-solubility for photodynamic therapy and diagnosis.
abstract: Photodynamic therapy (PDT) exploits light interactions and photosensitizers to induce cytotoxic reactive oxygen species. Photodynamic diagnosis (PDD) uses the phenomenon of photosensitizer emitting fluorescence to distinguish some tumors from normal tissue. The standard photosensitizer used for PDD is 5-aminolevulinic acid (5-ALA), although it is not entirely satisfactory. We previously reported glucose-conjugated chlorin (G-chlorin) as a more effective photosensitizer than another widely used photosensitizer, talaporfin sodium (TS); however, G-chlorin is hydrophobic. We synthesized oligosaccharide-conjugated chlorin (O-chlorin) with improved water-solubility. We report herein on its accumulation and cytotoxicity. O-chlorin was synthesized and examined for solubility. Flow cytometric analysis was performed to evaluate O-chlorin accumulation in cancer cells. To evaluate the intracellular localization of photosensitizer, cells were stained with O-chlorin and organelle-specific fluorescent probes. We then measured the in vitro fluorescence of various photosensitizers and the half-maximal inhibitory concentrations to evaluate effects in PDD and PDT, respectively. Xenograft tumor models were established, and antitumor and visibility effects were analyzed. O-chlorin was first shown to be hydrophilic. Flow cytometry then revealed a 20- to 40-times higher accumulation of O-chlorin in cancer cells than of TS, and a 7- to 23-times greater fluorescence than 5-ALA. In vitro, the cytotoxicity of O-chlorin PDT was stronger than that of TS PDT, and O-chlorin tended to accumulate in lysosomes. In vivo, O-chlorin showed the best effect in PDT and PDD compared to other photosensitizers.O-chlorin was hydrophilic and showed excellent tumor accumulation and fluorescence. O-chlorin is promising as a next-generation bifunctional photosensitizer candidate for both PDT and PDD.
authors.affiliation: Departments of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Hirotada
authors.initials: H
authors.lastname: Nishie
authors.affiliation: Departments of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kataoka
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Yano
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Kikuchi
authors.affiliation: Departments of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, Yamagata, Yonezawa 992-8510, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Narumi
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Nakaku, Sakai, Osaka 599-8531, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nomoto
authors.affiliation: Departments of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Kubota
authors.affiliation: Departments of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Joh
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004938:Esophageal Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology*; D011166:Porphyrins / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology*; D012995:Solubility; D014867:Water / Q000737:chemistry; D023041:Xenograft Model Antitumor Assays
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; D014867:Water; C006969:chlorin
keywords: Warburg effect; glycoconjugated chlorin; oligosaccharide-conjugated chlorin; photodynamic diagnosis; photodynamic therapy