title: 5-Fluorouracil induced Fas upregulation associated with apoptosis in liver metastases of colorectal cancer patients.
abstract: 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.
  
  
  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.
authors: Department of Medical Oncology, University Hospital Vrije Universiteit, Amsterdam, The Netherlands.
authors: H H
authors: HH
authors: Backus
authors: D F
authors: DF
authors: Dukers
authors: C J
authors: CJ
authors: van Groeningen
authors: W
authors: W
authors: Vos
authors: E
authors: E
authors: Bloemena
authors: D
authors: D
authors: Wouters
authors: J M
authors: JM
authors: van Riel
authors: K
authors: K
authors: Smid
authors: G
authors: G
authors: Giaccone
authors: H M
authors: HM
authors: Pinedo
authors: G J
authors: GJ
authors: Peters
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary; D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000378:metabolism; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D014408:Biomarkers, Tumor / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D053222:Fas Ligand Protein; D005260:Female; D005434:Flow Cytometry; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D007124:Immunoenzyme Techniques; D007262:Infusions, Intravenous; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism; D015854:Up-Regulation; D019014:fas Receptor / Q000378:metabolism*
chemical_list: D000951:Antigens, Neoplasm; D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D019014:fas Receptor; D005472:Fluorouracil