Strong enhancement of recombinant cytosine deaminase activity in Bifidobacterium longum for tumor-targeting enzyme/prodrug therapy.
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.
Hamaji
Yoshinori
Y
Department of Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
Fujimori
Minoru
M
Sasaki
Takayuki
T
Matsuhashi
Hitomi
H
Matsui-Seki
Keiichi
K
Shimatani-Shibata
Yuko
Y
Kano
Yasunobu
Y
Amano
Jun
J
Taniguchi
Shun'ichiro
S
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
D000963:Antimetabolites; D000970:Antineoplastic Agents; D011355:Prodrugs; D011994:Recombinant Proteins; D005437:Flucytosine; D043525:Cytosine Deaminase; D005472:Fluorouracil