CD47 ligation induces caspase-independent cell death in chronic lymphocytic leukemia

V Mateo, L Lagneaux, D Bron, G Biron, M Armant… - Nature medicine, 1999 - nature.com
V Mateo, L Lagneaux, D Bron, G Biron, M Armant, G Delespesse, M Sarfati
Nature medicine, 1999nature.com
Thrombospondin forms a'molecular bridge'between phagocytic and apoptotic cells through
interaction with αvβ3/CD36. We report here that engagement of CD47, a newly described
thrombospondin receptor, by immobilized monoclonal antibody against CD47 or by
thrombospondin induced in all B-cell chronic lymphocytic leukemia clones the cytoplasmic
features of apoptosis (cell shrinkage, decrease in mitochondrial transmembrane potential
and phosphatidylserine externalization) without the nuclear features (chromatin …
Abstract
Thrombospondin forms a'molecular bridge'between phagocytic and apoptotic cells through interaction with αvβ3/CD36. We report here that engagement of CD47, a newly described thrombospondin receptor, by immobilized monoclonal antibody against CD47 or by thrombospondin induced in all B-cell chronic lymphocytic leukemia clones the cytoplasmic features of apoptosis (cell shrinkage, decrease in mitochondrial transmembrane potential and phosphatidylserine externalization) without the nuclear features (chromatin condensation, appearance of single-stranded DNA, DNA fragmentation and cleavage of poly ADP-ribose polymerase). These cytoplasmic events of apoptosis were not prevented by the addition of caspase inhibitor z-VAD-fmk, or by the presence of survival factors (such as interleukin-4 and gamma interferon) or cell activation. Morphological studies confirmed the integrity of the nucleus and showed swelling of the mitochondria. This caspase-independent death pathway may be relevant to the development of alternate therapeutic strategies in chronic lymphocytic leukemia, which remains an incurable disease.
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