Influence of chemotherapeutic agents and cytokines on the expression of 5-fluorouracil-associated enzymes in human colon cancer cell lines

J Gastroenterol. 2006 Feb;41(2):140-50. doi: 10.1007/s00535-005-1733-6.

Abstract

Background: Several studies have demonstrated that intratumoral expression of catabolizing and anabolizing enzymes for 5-fluorouracil (5-FU) is important in the response of cancers to 5-FU-based chemotherapy. We investigated the influence of other chemotherapeutic agents or cytokines, which are often administered for enhancing the efficacy of 5-FU, on the tumoral expression of 5-FU-associated enzymes, i.e., dihydropyrimidine dehydrogenase (DPD), thymidylate synthase (TS), orotate phosphoribosyl transferase (OPRT), and thymidine phosphorylase (TP).

Methods: Human colon cancer cell lines (HT-29, Caco-2, and DLD-1) were incubated with 5-FU and with 5-FU combined with cisplatin, camptothecin, paclitaxel, mitomycin C, interferon, or TNF-related apoptosis-inducing ligand. mRNA expression of 5-FU-associated enzymes was assessed by real-time PCR. Activity of each enzyme and intracellular 5-FU accumulation after incubation with such agents were also evaluated.

Results: Each agent had a synergistic effect on the cytotoxicity of 5-FU. All chemotherapeutic agents other than cytokines induced marked alteration of the mRNA expression profile of 5-FU-associated enzymes; depression of DPD, elevation of TS, and slight suppression of OPRT and TP. In accordance with mRNA expression, enzyme activity of DPD was significantly depressed by such agents. Furthermore, although 5-FU itself increased DPD mRNA expression, a mechanism considered to be related to the acquisition of 5-FU resistance, the addition of cisplatin or camptothecin significantly inhibited the 5-FU-induced elevation of DPD.

Conclusions: 5-FU-associated enzymes in colon cancer cells were greatly influenced by various chemotherapeutic agents; in particular, DPD expression was depressed. These results appear important in planning chemotherapy and also in understanding the development of adverse effects of 5-FU.

MeSH terms

  • Antimetabolites, Antineoplastic / pharmacology*
  • Apoptosis
  • Caco-2 Cells
  • Camptothecin / pharmacology
  • Cell Line, Tumor
  • Cisplatin / pharmacology
  • Colonic Neoplasms / enzymology*
  • Cytokines / pharmacology*
  • Dihydrouracil Dehydrogenase (NADP) / metabolism
  • Fluorouracil / metabolism*
  • Fluorouracil / pharmacology*
  • HT29 Cells
  • Humans
  • Interferons / pharmacology
  • Ligands
  • Mitomycin / pharmacology
  • Orotate Phosphoribosyltransferase / metabolism
  • Paclitaxel / pharmacology
  • RNA, Messenger / analysis
  • Thymidine Phosphorylase / metabolism
  • Thymidylate Synthase / metabolism

Substances

  • Antimetabolites, Antineoplastic
  • Cytokines
  • Ligands
  • RNA, Messenger
  • Mitomycin
  • Interferons
  • Dihydrouracil Dehydrogenase (NADP)
  • Thymidylate Synthase
  • Orotate Phosphoribosyltransferase
  • Thymidine Phosphorylase
  • Paclitaxel
  • Cisplatin
  • Fluorouracil
  • Camptothecin