Combined suicide gene therapy for human colon cancer cells using adenovirus-mediated transfer of escherichia coli cytosine deaminase gene and Escherichia coli uracil phosphoribosyltransferase gene with 5-fluorocytosine.
The virus-directed enzyme/prodrug system using the Escherichia coli cytosine deaminase (CD) gene and 5-fluorocytosine (5-FC) suffers from a sensitivity limitation in many tumor cells. The E. coil uracil phosphoribosyltransferase (UPRT), which is a pyrimidine salvage enzyme, directly converts 5-fluorouracil (5-FU) to 5-fluorouridine monophosphate at the first step of its activating pathway. To improve the antitumoral effect of the CD/5-FC system, we investigated a combined suicide gene transduction therapy for human colon cancer cells using two separate adenovirus vectors expressing the E. coli CD and E. coli UPRT genes and systemic 5-FC administration (the CD, UPRT/5-FC system). The present study demonstrates that the CD, UPRT/5-FC system generates a co-operative effect of CD and UPRT, resulting in dramatic increases in both RNA- and DNA-directed active forms, including 5-fluorouridine triphosphate incorporated into RNA, 5-fluorodeoxyuridine monophosphate, and the thymidylate synthase inhibition rate, compared with the CD/5-FC system. Furthermore a significant increase in the 5-FC sensitivity of colon cancer cells was demonstrated in the CD, UPRT/5-FC system compared with the CD/5-FC system in vitro and in vivo. These results suggest that the CD, UPRT/5-FC system is a powerful approach in gene therapy for colorectal cancer.
Koyama
F
F
First Department of Surgery, Nara Medical University, Kashihara-city, Japan.
Sawada
H
H
Hirao
T
T
Fujii
H
H
Hamada
H
H
Nakano
H
H
D000256:Adenoviridae / Q000201:enzymology / Q000235:genetics*; D000818:Animals; D003110:Colonic Neoplasms / Q000235:genetics / Q000628:therapy*; D003131:Combined Modality Therapy; D043525:Cytosine Deaminase; D004247:DNA / Q000032:analysis; D017931:DNA Primers / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000201:enzymology*; D005437:Flucytosine / Q000627:therapeutic use*; D015870:Gene Expression / Q000187:drug effects; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009700:Nucleoside Deaminases / Q000235:genetics* / Q000378:metabolism; D010430:Pentosyltransferases / Q000235:genetics* / Q000378:metabolism; D012313:RNA / Q000032:analysis; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D012313:RNA; D004247:DNA; D005437:Flucytosine; D010430:Pentosyltransferases; C023269:uracil phosphoribosyltransferase; D009700:Nucleoside Deaminases; D043525:Cytosine Deaminase