Histidine-proline-rich glycoprotein has potent antiangiogenic activity mediated through the histidine-proline-rich domain.
Histidine-proline-rich glycoprotein (HPRG) is an abundant multidomain plasma protein evolutionarily related to high-molecular-weight kininogen. The cleaved form of high-molecular-weight kininogen has recently been demonstrated to exhibit antiangiogenic activities in vitro (J. C. Zhang et al., FASEB J., 14: 2589-2600, 2000), mediated primarily through domain 5. HPRG contains a histidine-proline-rich (H/P) domain with sequence and functional similarities to HKa-D5. We hypothesized that HPRG may also have antiangiogenic properties, localized within its H/P domain. The H/P domain is highly conserved among species, and because rabbit H/P domain is more resistant to internal proteolytic cleavage than the human domain, the rabbit HPRG (rbHPRG) was primarily used to assess the antiangiogenic activity of HPRG. Rabbit HPRG inhibited human umbilical vein endothelial cell (HUVEC) tube formation stimulated by fibroblast growth factor-2 (FGF-2) or vascular endothelial growth factor on a Matrigel surface as well as cell proliferation of FGF-2 stimulated HUVECs. The antiangiogenic activity of rbHPRG was localized to the H/P domain by use of proteolytic fragments of rbHPRG and was further confirmed and characterized in two in vivo models of angiogenesis: the chorioallantoic membrane of the chick assay and the mouse Matrigel plug assay. Caspase-3 activation was observed in HUVECs stimulated with FGF-2 in the presence of rbHPRG, suggesting that apoptosis of activated endothelial cells may be one of the mechanisms underlying its antiangiogenic activity. Finally, the H/P domain of rbHPRG reduced tumor cell number when tumor cells were co-inoculated in the Matrigel plug assay. In conclusion, the H/P domain within HPRG induces the apoptosis of activated endothelial cells leading to potent antiangiogenic effects.
Juarez
Jose C
JC
Attenuon, LLC, 10130 Sorrento Valley Road, Suite B, San Diego, CA 92121, USA.
Guan
Xiaojun
X
Shipulina
Natalya V
NV
Plunkett
Marian L
ML
Parry
Graham C
GC
Shaw
David Elliot
DE
Zhang
Jing-Chuan
JC
Rabbani
Shafaat A
SA
McCrae
Keith R
KR
Mazar
Andrew P
AP
Morgan
William T
WT
Doñate
Fernando
F
D020533:Angiogenesis Inhibitors / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002642:Chick Embryo; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000098:blood supply / Q000188:drug therapy / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D018919:Neovascularization, Physiologic / Q000187:drug effects; D010958:Plasminogen / Q000494:pharmacology; D011471:Prostatic Neoplasms / Q000098:blood supply / Q000188:drug therapy / Q000473:pathology; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000494:pharmacology* / Q000502:physiology; D011817:Rabbits; D020449:Repetitive Sequences, Amino Acid; D017386:Sequence Homology, Amino Acid; D000099053:Histidine-Rich Glycoprotein
D020533:Angiogenesis Inhibitors; D011506:Proteins; D000099053:Histidine-Rich Glycoprotein; D010958:Plasminogen