Microtubule disruption stimulates DNA synthesis in bovine endothelial cells and potentiates cellular response to basic fibroblast growth factor.
Cultured endothelial cells characteristically form a monolayer and become quiescent at saturation density. This study shows that microtubule destabilization in confluent cultures of bovine aortic endothelial cells stimulates fibroblast growth factor 2 (FGF-2, bFGF)-dependent DNA synthesis. Twenty-four hours after addition of the microtubule-disrupting drug colchicine, tritiated thymidine incorporation increases up to fivefold when compared to control cultures. Significant stimulation is seen with doses from 0.05 to 1.0 microgram/ml. The effect of colchicine is quantitatively similar to stimulation of the same cultures with 5 ng/ml FGF-2. Furthermore, the stimulation of DNA synthesis by colchicine can be completely blocked by the addition of a neutralizing antibody to FGF-2. This suggests that colchicine may stimulate bovine aortic endothelial cells by modulating endogenous FGF-2/receptor interactions or that colchicine acts by a different mechanism that requires the growth factor for mitogenicity. The combined effects of colchicine and FGF-2 are more than additive, which supports the idea that microtubule disruption may facilitate cellular response to FGF-2. Cytochalasin B, preventing actin polymerization, inhibits the mitogenic response to FGF-2 but not the response to colchicine. These results are best interpreted as evidence that colchicine stimulates endothelial cell DNA synthesis by a pathway that requires endogenous FGF-2 and may be facilitating cellular responsiveness to the growth factor by disrupting the monolayer via the cytoskeleton.
Liaw
L
L
Department of Pathology, University of Washington, Seattle 98195.
Schwartz
S M
SM
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002417:Cattle; D002478:Cells, Cultured; D003078:Colchicine / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000502:physiology*; D007150:Immunohistochemistry; D008870:Microtubules / Q000187:drug effects / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis
D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2; D004247:DNA; D003078:Colchicine