Cutting edge: the tumor counterattack hypothesis revisited: colon cancer cells do not induce T cell apoptosis via the Fas (CD95, APO-1) pathway.
The counterattack hypothesis, suggesting that cancer cells express Fas ligand (FasL) and are able to kill Fas-expressing tumor-infiltrating activated T cells, was supported by reports of the killing of Jurkat cells by FasL-expressing human colon cancer cell lines. Through the use of an improved cytotoxic assay in which soluble FasL and FasL-transfected KFL9 cells were used as positive controls, we show that none of seven human colon cancer cell lines induce apoptosis of two Fas-expressing target cell lines, Jurkat and L1210-Fas cells. Moreover, in coculture experiments, cancer cell monolayers do not inhibit the growth of Fas-expressing lymphoid cells. Although FasL mRNA and protein were detected in the extracts of the colon cancer cell lines, flow cytometry and confocal microscopy failed to detect the protein on the surface of tumor cells. These results suggest that the counterattack of tumor-infiltrating T lymphocytes by cancer cells may not account for immune tolerance toward tumor cells.
Favre-Felix
N
N
Department of Biology and Therapy of Cancer, Institut National de la Santé et de la Recherche Médicale U 517, Faculty of Medicine and Pharmacy, Dijon, France.
Fromentin
A
A
Hammann
A
A
Solary
E
E
Martin
F
F
Bonnotte
B
B
D000818:Animals; D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D017209:Apoptosis / Q000276:immunology*; D018938:Caco-2 Cells; D002455:Cell Division / Q000276:immunology; D018920:Coculture Techniques; D003110:Colonic Neoplasms / Q000276:immunology* / Q000378:metabolism; D053222:Fas Ligand Protein; D006131:Growth Inhibitors / Q000276:immunology; D019073:HT29 Cells; D006801:Humans; D019169:Jurkat Cells; D007939:Leukemia L1210; D008562:Membrane Glycoproteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology*; D019014:fas Receptor / Q000378:metabolism / Q000502:physiology*
D000951:Antigens, Neoplasm; D000954:Antigens, Surface; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D006131:Growth Inhibitors; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D019014:fas Receptor