Anti-angiogenic and vascular disrupting effects of C9, a new microtubule-depolymerizing agent.
OBJECTIVE
The critical role of blood supply in the growth of solid tumours makes blood vessels an ideal target for anti-tumour drug discovery. The anti-angiogenic and vascular disrupting activities of C9, a newly synthesized microtubule-depolymerizing agent, were investigated with several in vitro and in vivo models. Possible mechanisms involved in its activity were also assessed.


METHODS
Microtubule-depolymerizing actions were assessed by surface plasmon resonance binding, competitive inhibition and cytoskeleton immunofluorescence. Anti-angiogenic and vascular disrupting activities were tested on proliferation, migration, tube formation with human umbilical vein endothelial cells, and in rat aortic ring, chick chorioallantoic membrane and Matrigel plug assays. Western blots and Rho activation assays were employed to examine the role of Raf-MEK-ERK (mitogen-activated ERK kinase, extracellular signal-regulated kinase) and Rho/Rho kinase signalling.


RESULTS
C9 inhibited proliferation, migration and tube formation of endothelial cells and inhibited angiogenesis in aortic ring and chick chorioallantoic membrane assays. C9 induced disassembly of microtubules in endothelial cells and down-regulated Raf-MEK-ERK signalling activated by pro-angiogenic factors. In addition, C9 disrupted capillary-like networks and newly formed vessels in vitro and rapidly decreased perfusion of neovasculature in vivo. Endothelial cell contraction and membrane blebbing induced by C9 in neovasculature was dependent on the Rho/Rho kinase pathway.


CONCLUSIONS
Anti-angiogenic and vascular disruption by C9 was associated with changes in morphology and function of endothelial cells, involving the Raf-MEK-ERK and Rho/Rho kinase signalling pathways. These findings strongly suggest that C9 is a new microtubule-binding agent that could effectively target tumour vasculature.
Ren
Xuan
X
Division of Anti-tumor Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
Dai
Mei
M
Lin
Li-Ping
LP
Li
Pui-Kai
PK
Ding
Jian
J
D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply*; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects* / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014404:Tubulin / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology*; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D054460:rho-Associated Kinases / Q000378:metabolism
C546021:1,3-dihydro-6-methoxy-1-methyl-3-((3,4,5-trimethoxyphenyl)methylene)-2H-indol-2-one; D020533:Angiogenesis Inhibitors; D007211:Indoles; D014404:Tubulin; D050257:Tubulin Modulators; D019908:Proto-Oncogene Proteins c-raf; D054460:rho-Associated Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020930:MAP Kinase Kinase Kinases; D020741:rho GTP-Binding Proteins