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

Cancer Gene Ther. 2000 Jul;7(7):1015-22. doi: 10.1038/sj.cgt.7700189.


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.

MeSH terms

  • Adenoviridae / enzymology
  • Adenoviridae / genetics*
  • Animals
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / therapy*
  • Combined Modality Therapy
  • Cytosine Deaminase
  • DNA / analysis
  • DNA Primers / chemistry
  • Dose-Response Relationship, Drug
  • Escherichia coli / enzymology*
  • Flucytosine / therapeutic use*
  • Gene Expression / drug effects
  • Gene Transfer Techniques
  • Genetic Therapy*
  • Genetic Vectors
  • Humans
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Neoplasm Transplantation
  • Nucleoside Deaminases / genetics*
  • Nucleoside Deaminases / metabolism
  • Pentosyltransferases / genetics*
  • Pentosyltransferases / metabolism
  • RNA / analysis
  • Tumor Cells, Cultured


  • DNA Primers
  • RNA
  • DNA
  • Flucytosine
  • Pentosyltransferases
  • uracil phosphoribosyltransferase
  • Nucleoside Deaminases
  • Cytosine Deaminase