title: Enhanced 5-fluorouracil cytotoxicity in high cyclooxygenase-2 expressing colorectal cancer cells and xenografts induced by non-steroidal anti-inflammatory drugs via downregulation of dihydropyrimidine dehydrogenase.
abstract: OBJECTIVE
  To prove that 5-FU cytotoxicity could be increased by combination with low-dose non-steroidal anti-inflammatory drugs (NSAIDs) (indomethacin or NS-398) in high cyclooxygenase-2- (COX-2) expressing cells and xenografts through the modulation of dihydropyrimidine dehydrogenase (DPD) mRNA expression and/or enzyme activity.
  
  
  METHODS
  HT-29 cells were grown on collagen IV coated plates (HT-29-C). The antiproliferative effect of 5-fluorouracil (5-FU) +/- NSAIDs was examined on non-COX-2 expressing HT-29 and COX-2-expressing HT-29-C cells by sulphorhodamine B assay. The COX-2 and DPD expressions were visualized by immunofluorescent staining, and prostaglandin E(2) levels were measured by ELISA kit. The HT-29 xenograft was established in SCID mice and treated with 5-FU +/- NSAIDs for 5 days. The tumor volume, enzyme activity, and DPD mRNA expression were investigated by caliper, radioenzymatic method, and real-time RT-PCR, respectively. The drug interaction was calculated for both combinations (5-FU + indomethacin and 5-FU + NS-398).
  
  
  RESULTS
  Collagen IV up-regulated significantly the COX-2 and DPD mRNA, and protein expressions, and also their enzyme activities in HT-29 cells. NSAIDs enhanced in a synergistic manner the cytotoxic effect of 5-FU treatment both in vitro and in vivo. Downregulation of DPD was observed after 5-FU monotherapy, but the combined effect of NSAIDs and 5-FU on DPD mRNA expression, and enzyme activity was superior to the effect of 5-FU alone.
  
  
  CONCLUSIONS
  Since 5-FU + NSAID treatment can alter the DPD enzyme activity resulting in an enhanced cytotoxic effect, further studies in clinical practice are warranted.
authors.affiliation: Department of Clinical Research, National Institute of Oncology, Budapest, Hungary.
authors.forename: Andrea
authors.initials: A
authors.lastname: Réti
authors.forename: Eva
authors.initials: E
authors.lastname: Pap
authors.forename: Vilmos
authors.initials: V
authors.lastname: Adleff
authors.forename: András
authors.initials: A
authors.lastname: Jeney
authors.forename: Judit
authors.initials: J
authors.lastname: Kralovánszky
authors.forename: Barna
authors.initials: B
authors.lastname: Budai
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003094:Collagen / Q000494:pharmacology; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000201:enzymology* / Q000473:pathology; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000096:biosynthesis*; D015232:Dinoprostone / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004347:Drug Interactions; D005109:Extracellular Matrix / Q000187:drug effects / Q000201:enzymology; D005455:Fluorescent Antibody Technique; D005472:Fluorouracil / Q000494:pharmacology*; D019073:HT29 Cells; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D009578:Nitrobenzenes / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013449:Sulfonamides / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000964:Antimetabolites, Antineoplastic; D052246:Cyclooxygenase 2 Inhibitors; D009578:Nitrobenzenes; D012333:RNA, Messenger; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D003094:Collagen; D051546:Cyclooxygenase 2; D042943:Dihydrouracil Dehydrogenase (NADP); D015232:Dinoprostone; D005472:Fluorouracil; D007213:Indomethacin