title: Circumvention of 5-fluorouracil resistance in human stomach cancer cells by uracil phosphoribosyltransferase gene transduction.
abstract: A human stomach cancer cell line with acquired resistance to 5-fluorouracil (5-FU), NUGC-3/5FU/ L, has been found to possess reduced ability to convert 5-FU into active metabolites. We attempted in vitro gene therapy for this 5-FU-resistant cell line. NUGC-3 and NUGC-3/5FU/L cells were infected with recombinant adenovirus (Ad) containing Escherichia coli uracil phosphoribosyltransferase (UPRT) gene driven by CAG promoter (CA), AdCA-UPRT, and changes in their 5-FU metabolism and sensitivity were investigated. Activities of orotate phosphoribosyltransferase increased from 10.2 and 1.56 (nmol/mg protein/30 min) in the uninfected cells of NUGC-3 and NUGC-3/5FU/L to 216 and 237, respectively, after the transfection of UPRT gene. The 5-FU nucleotide level in the acid-insoluble fraction increased from 7.32 to 15.9 (pmol/mg protein) in NUGC-3 cells on infection with AdCA-UPRT, and in NUGC-3/5FU/L cells it increased from 1.91 to 21.4. The 50% growth-inhibition concentration (IC50) was 12.7 micromol/liter for NUGC-3 and much higher than 100 micromol/liter for NUGC-3/5FU/L, indicating over 8-fold resistance. NUGC-3/ SFU/L transfected with the UPRT gene showed very high sensitivity to 5-FU with an IC50 of 3.2 micromol/liter. The high resistance in this metabolic activation-deficient cell line was thus completely reversed by transduction of an exogenous gene coding for a 5-FU-anabolizing enzyme.
authors.affiliation: Division of Experimental Chemotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo.
authors.forename: M
authors.initials: M
authors.lastname: Inaba
authors.forename: H
authors.initials: H
authors.lastname: Sawada
authors.forename: A
authors.initials: A
authors.lastname: Sadata
authors.forename: H
authors.initials: H
authors.lastname: Hamada
mesh_terms: D000256:Adenoviridae / Q000235:genetics / Q000502:physiology; D003600:Cytosol / Q000201:enzymology / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005472:Fluorouracil / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D017930:Genes, Reporter; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D020128:Inhibitory Concentration 50; D010430:Pentosyltransferases / Q000235:genetics* / Q000378:metabolism*; D010754:Phosphoribosyl Pyrophosphate / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D014161:Transduction, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured; D014500:Uracil Nucleotides / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D014500:Uracil Nucleotides; D010754:Phosphoribosyl Pyrophosphate; C016462:5-fluorouridine 5'-phosphate; D010430:Pentosyltransferases; C023269:uracil phosphoribosyltransferase; D005472:Fluorouracil