Expression of vascular endothelial growth factor-b in human astrocytoma.
Growth of human malignant gliomas is stringently dependent on an angiogenic process that probably involves vascular endothelial growth factor (VEGF). Expressions of mRNA coding for the different forms of VEGF were analyzed in surgical specimens from human astrocytomas. Low levels of placental growth factor (PGF) and VEGFC mRNA were observed in polymerase chain reaction, but not in Northern blot experiments. VEGF mRNA was found in some but not all grade and grade IV astrocytomas. VEGFB mRNA was observed in all tissue samples analyzed irrespective of the tumor grade. A new splice variant of VEGFB (VEGFB155) that lacks exons 5 and 6 is described. Expressions of VEGF mRNA in cultured glioblastomas cells were upregulated by hypoxia, but the sensitivity of the cells to hypoxia was reduced as compared with normal rat astrocytes. VEGF expression was depressed by dexamethasone. Expressions of VEGFB mRNA were affected neither by hypoxia nor by dexamethasone. The results indicate a coexpression of VEGF mRNA and VEGFB mRNA in human astrocytomas. Expression of VEGFB is markedly different from that of VEGF. Possible roles of VEGFB as a cofactor for hypoxia-induced angiogenesis in human astrocytomas are discussed.
Gollmer
J C
JC
Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France.
Ladoux
A
A
Gioanni
J
J
Paquis
P
P
Dubreuil
A
A
Chatel
M
M
Frelin
C
C
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001254:Astrocytoma / Q000098:blood supply / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D001483:Base Sequence; D015152:Blotting, Northern; D001932:Brain Neoplasms / Q000098:blood supply / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015687:Cell Hypoxia; D003907:Dexamethasone / Q000494:pharmacology; D016228:Endothelial Growth Factors / Q000096:biosynthesis* / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005909:Glioblastoma / Q000098:blood supply / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008222:Lymphokines / Q000096:biosynthesis / Q000235:genetics; D008577:Meningeal Neoplasms / Q000098:blood supply / Q000235:genetics / Q000378:metabolism; D008579:Meningioma / Q000098:blood supply / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D012334:RNA, Neoplasm / Q000096:biosynthesis; D051381:Rats; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D042561:Vascular Endothelial Growth Factor B; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D042461:Vascular Endothelial Growth Factor A; D042561:Vascular Endothelial Growth Factor B; D042442:Vascular Endothelial Growth Factors; D003907:Dexamethasone