5-Fluorouracil induced Fas upregulation associated with apoptosis in liver metastases of colorectal cancer patients

H. H J Backus, D. F. Dukers, C. J. Van Groeningen, W. Vos, E. Bloemena, D. Wouters, J. M G H Van Riel, K. Smid, G. Giaccone, H. M. Pinedo, G. J. Peters

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Background: In vitro, thymidylate synthase (TS) inhibition by 5-fluorouracil (5-FU) induces thymineless apoptosis possibly via Fas receptor-Fas ligand interactions and cell-cycle arrest. In colorectal cancer patients we evaluated whether 5-FU administration also resulted in apoptosis and cell-cycle arrest and which proteins might be involved. Patients and methods: Biopsy specimens were taken from 36 patients 2, 22 or 46 hours after administration of 500 mg/m2 5-FU, and from 12 control patients who did not receive 5-FU. In frozen tissue-sections from liver metastases immunohistochemistry was performed with antibodies directed against p53, p21, E2F2, Rb, Ki67 and TS (cell-cycle related) and bax, BCL-2, BCL-x, mcl-1, PARP, caspase-3, Fas receptor and Fas ligand (apoptosis related). Apoptosis was determined by M30 immunostaining, which recognises a cleavage product of cytokeratin 18. Results: Fas receptor expression was 50% higher (P=0.036) 46 hours after 5-FU administration compared to the control group. This was associated with a 12% increase (P <0.02) in M30 positive tumour cells and with elevation of caspase-3 and PARP expression. The expression of Ki67 and E2F2 was 30% lower after 46 hours compared to the control group, whereas TS was 56% lower after 2 hours and 32% higher again after 46 hours. No differences in the expression of the other proteins were found. Conclusions: These results suggest that 5-FU decreases proliferation status and induces apoptosis possibly via the Fas pathway. Since Fas mediated cell killing is important for cytotoxic T cells this indicates that clinical studies combining immunotherapy for activation of T cells and chemotherapy using 5-FU might be very effective.

Original languageEnglish (US)
Pages (from-to)209-216
Number of pages8
JournalAnnals of Oncology
Issue number2
StatePublished - 2001
Externally publishedYes


  • 5-Fluorouracil
  • Apoptosis
  • Cell-cycle arrest
  • Colorectal cancer
  • Fas
  • Thymidylate synthase

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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