Angiostatin(4.5)-mediated apoptosis of vascular endothelial cells.
Angiostatin, a proteolytic cleavage product of plasminogen, acts via a selective, yet poorly understood mechanism to potently inhibit angiogenesis (M. S. O'Reilly et al., Cell, 79: 315-328, 1994). Vascular endothelial cell proliferation assays revealed that angiostatin(4.5), a naturally occurring human isoform consisting of plasminogen kringle domains 1-4 and most of kringle domain 5 (G. A. Soff, Cancer Metastasis Rev., 19: 97-107, 2000), dose dependently reduces cell number despite the presence of a potent stimulus of proliferation. Flow cytometry using the vital dyes Hoechst 33342 and Pyronin Y revealed that approximately 40% of both control and angiostatin(4.5)-treated cells were in the proliferative phase, indicating that cell cycle progression is not impaired by exposure to angiostatin(4.5). Both bovine aortic endothelial cells and human umbilical endothelial cells were shown to undergo apoptosis in response to angiostatin(4.5). Caspases-3, -8, and -9 activation, specified by cleavage of fluorophore-conjugated specific peptide substrates, revealed a cascade of caspase activation that peaks at 36 h of angiostatin(4.5) treatment. Angiostatin(4.5) exposure induced release of cytochrome c from mitochondria in a caspase-dependent manner, but a pan-caspase inhibitor, zVAD-fmk, blocked cytochrome c release. Overall, these data indicate that human angiostatin(4.5) may function in vivo to block blood vessel formation by specifically inducing vascular endothelial cells to apoptose in a process likely involving both the intrinsic and extrinsic apoptosis pathways.
Hanford
Holly Anne
HA
Northwestern University, Feinberg School of Medicine, Department of Medicine, Division of Hematology/Oncology, Chicago, Illinois 60611, USA.
Wong
Christie A
CA
Kassan
Hallie
H
Cundiff
Deborah L
DL
Chandel
Navdeep
N
Underwood
Suzanne
S
Mitchell
Christopher A
CA
Soff
Gerald A
GA
D043168:Angiostatins; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002417:Cattle; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003574:Cytochrome c Group / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology*; D010958:Plasminogen / Q000494:pharmacology*; D016196:S Phase / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D017304:Annexin A5; D003574:Cytochrome c Group; D010446:Peptide Fragments; D043168:Angiostatins; D010958:Plasminogen; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases