CXCL12 and vascular endothelial growth factor synergistically induce neoangiogenesis in human ovarian cancers.
Ovarian carcinomas have a poor prognosis, often associated with multifocal i.p. dissemination accompanied by intense neovascularization. To examine tumor angiogenesis in the tumor microenvironment, we studied malignant ascites and tumors of patients with untreated ovarian carcinoma. We observed that malignant ascites fluid induced potent in vivo neovascularization in Matrigel assay. We detected a sizable amount of vascular endothelial cell growth factor (VEGF) in malignant ascites. However, pathologic concentration of VEGF is insufficient to induce in vivo angiogenesis. We show that ovarian tumors strongly express CXC chemokine stromal-derived factor (SDF-1/CXCL12). High concentration of CXCL12, but not the pathologic concentration of CXCL12 induces in vivo angiogenesis. Strikingly, pathologic concentrations of VEGF and CXCL12 efficiently and synergistically induce in vivo angiogenesis. Migration, expansion, and survival of vascular endothelial cells (VEC) form the essential functional network of angiogenesis. We further provide a mechanistic basis for explaining the interaction between CXCL12 and VEGF. We show that VEGF up-regulates the receptor for CXCL12, CXCR4 expression on VECs, and synergizes CXCL12-mediated VEC migration. CXCL12 synergizes VEGF-mediated VEC expansion and synergistically protects VECs from sera starvation-induced apoptosis with VEGF. Finally, we show that hypoxia synchronously induces tumor CXCL12 and VEGF production. Therefore, hypoxia triggered tumor CXCL12 and VEGF form a synergistic angiogenic axis in vivo. Hypoxia-induced signals would be the important factor for initiating and maintaining an active synergistic angiogeneic pathway mediated by CXCL12 and VEGF. Thus, interrupting this synergistic axis, rather than VEGF alone, will be a novel efficient antiangiogenesis strategy to treat cancer.
Kryczek
Ilona
I
Tulane University Health Science Center, New Orleans, LA 70112, USA.
Lange
Andrzej
A
Mottram
Peter
P
Alvarez
Xavier
X
Cheng
Pui
P
Hogan
Melina
M
Moons
Lieve
L
Wei
Shuang
S
Zou
Linhua
L
Machelon
Véronique
V
Emilie
Dominique
D
Terrassa
Margarita
M
Lackner
Andrew
A
Curiel
Tyler J
TJ
Carmeliet
Peter
P
Zou
Weiping
W
D000818:Animals; D001201:Ascites / Q000378:metabolism / Q000473:pathology; D015687:Cell Hypoxia / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000096:biosynthesis / Q000494:pharmacology* / Q000502:physiology; D004357:Drug Synergism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D051379:Mice; D009389:Neovascularization, Pathologic / Q000378:metabolism / Q000473:pathology; D010051:Ovarian Neoplasms / Q000098:blood supply* / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000494:pharmacology* / Q000502:physiology
C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A