Up-regulation of connective tissue growth factor in endothelial cells by the microtubule-destabilizing agent combretastatin A-4.
Incubation of microvascular endothelial cells with combretastatin A-4 phosphate (CA-4P), a microtubule-destabilizing compound that preferentially targets tumor vessels, altered cell morphology and induced scattering of Golgi stacks. Concomitantly, CA-4P up-regulated connective tissue growth factor (CTGF/CCN2), a pleiotropic factor with antiangiogenic properties. In contrast to the effects of other microtubule-targeting agents such as colchicine or nocodazole, up-regulation of CTGF was only detectable in sparse cells, which were not embedded in a cell monolayer. Furthermore, CA-4P induced CTGF expression in endothelial cells, forming tube-like structures on basement membrane gels. Up-regulation of CTGF by CA-4P was dependent on Rho kinase signaling and was increased when p42/44 mitogen-activated protein kinase was inhibited. Additionally, FoxO transcription factors were identified as potent regulators of CTGF expression in endothelial cells. Activation of FoxO transcription factors by inhibition of phosphatidylinositol 3-kinase/AKT signaling resulted in a synergistic increase in CA-4P-mediated CTGF induction. CA-4P-mediated expression of CTGF was thus potentiated by the inhibition of kinase pathways, which are targets of novel antineoplastic drugs. Up-regulation of CTGF by low concentrations of CA-4P may thus occur in newly formed tumor vessels and contribute to the microvessel destabilization and antiangiogenic effects of CA-4P observed in vivo.
Samarin
Jana
J
Department of Nephrology and Hypertension, University of Erlangen-Nürnberg, University Hospital Erlangen, Erlangen, Germany.
Rehm
Margot
M
Krueger
Bettina
B
Waschke
Jens
J
Goppelt-Struebe
Margarete
M
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D015153:Blotting, Western; D002478:Cells, Cultured; D003078:Colchicine / Q000494:pharmacology; D055513:Connective Tissue Growth Factor / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000378:metabolism; D051379:Mice; D008870:Microtubules / Q000187:drug effects*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013267:Stilbenes / Q000494:pharmacology*; D050257:Tubulin Modulators / Q000494:pharmacology; D015854:Up-Regulation
D000972:Antineoplastic Agents, Phytogenic; D003078:Colchicine; D055513:Connective Tissue Growth Factor; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger; D013267:Stilbenes; D050257:Tubulin Modulators; C526318:CCN2 protein, mouse; C467200:Foxo1 protein, mouse; C058728:fosbretabulin