Perforin and granzyme B induce apoptosis in FasL-resistant colon carcinoma cells |
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Authors: | David Vermijlen Christopher J Froelich Dianzhong Luo Nathalie Suarez-Huerta Bernard Robaye Eddie Wisse |
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Institution: | (1) Laboratory for Cell Biology and Histology, Free University Brussels (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium e-mail: dvermijl@cyto.vub.ac.be Fax: +32-2-4774405, BE;(2) Department of Medicine, Evanston Hospital, Northwestern University, 2650 Ridge Ave., Evanston, IL 60201, USA, US;(3) Institut de Recherche Interdisciplinaire en Biologie Humaine et Nucléaire (IRIBHN), Route de Lennik 808, Free University of Brussels (ULB), Brussels, Belgium, BE |
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Abstract: | Cytotoxic lymphocytes may induce apoptosis in their target cells by the FasL (Fas ligand) pathway or the perforin/granzyme
B pathway. It has been shown that Fas-expressing colon carcinoma (CC) cells are resistant to FasL-mediated apoptosis. The
aims of this study were to determine whether CC cells are also resistant to perforin/granzyme B and whether the FasL resistance
lies upstream of caspase-3 activation. The resistance of the Fas-expressing rat CC531s cells to the FasL pathway was confirmed
by treating them with recombinant human soluble FasL, using rat hepatocytes as a positive control. The intracellular delivery
of granzyme B by sublytic concentrations of perforin, on the other hand, resulted in many features of apoptosis (chromatin
condensation, nucleus fragmentation, loss of microvilli and internucleosomal DNA fragmentation) within 3 h. Since both the
FasL and perforin/granzyme B pathways converge at caspase-3, we measured caspase-3 activity to learn whether the FasL resistance
was due to failure to activate this crucial executioner. Caspase-3 activation occurred in CC531s cells after perforin/granzyme
B treatment, but not after the addition of recombinant FasL. Furthermore, we showed that caspase-3 activity is involved in
the execution of perforin/granzyme-B-induced apoptosis in CC531s cells, since the cell-permeable caspase-3 inhibitor Z-DEVD-FMK
abrogated DNA fragmentation. Together, these results suggest that CC cells are sensitive to perforin/granzyme-B-induced apoptosis
by activating caspase-3 and FasL resistance lies upstream of this executioner caspase.
Received: 20 November 2000 / Accepted: 8 March 2001 |
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Keywords: | Colon carcinoma Apoptosis Perforin Granzyme B Fas ligand |
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