title: Strong enhancement of recombinant cytosine deaminase activity in Bifidobacterium longum for tumor-targeting enzyme/prodrug therapy.
abstract: In our previous studies, a strain of the nonpathogenic, anaerobic, intestinal bacterium, Bifidobacterium longum (B. longum), was found to be localized selectively and to proliferate within solid tumors after systemic administration. In addition, B. longum transformed with the shuttle-plasmid encoding the cytosine deaminase (CD) gene expressed active CD, which deaminated the prodrug 5-fluorocytosine (5-FC) to the anticancer agent 5-fluorouracil (5-FU). We also reported antitumor efficacy with the same plasmid in several animal experiments. In this study, we constructed a novel shuttle-plasmid, pAV001-HU-eCD-M968, which included the mutant CD gene with a mutation at the active site to increase the enzymatic activity. In addition, the plasmid-transformed B. longum produces mutant CD and strongly increased (by 10-fold) its 5-FC to 5-FU enzymatic activity. The use of B. longum harboring the new shuttle-plasmid increases the effectiveness of our enzyme/prodrug strategy.
authors.affiliation: Department of Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hamaji
authors.forename: Minoru
authors.initials: M
authors.lastname: Fujimori
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sasaki
authors.forename: Hitomi
authors.initials: H
authors.lastname: Matsuhashi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Matsui-Seki
authors.forename: Yuko
authors.initials: Y
authors.lastname: Shimatani-Shibata
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Kano
authors.forename: Jun
authors.initials: J
authors.lastname: Amano
authors.forename: Shun'ichiro
authors.initials: S
authors.lastname: Taniguchi
mesh_terms: D000963:Antimetabolites / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D001644:Bifidobacterium / Q000201:enzymology* / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D043525:Cytosine Deaminase / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D005437:Flucytosine / Q000378:metabolism*; D005472:Fluorouracil / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011355:Prodrugs / Q000737:chemistry* / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000963:Antimetabolites; D000970:Antineoplastic Agents; D011355:Prodrugs; D011994:Recombinant Proteins; D005437:Flucytosine; D043525:Cytosine Deaminase; D005472:Fluorouracil