title: Identification of sokotrasterol sulfate as a novel proangiogenic steroid.
abstract: The potential to promote neovascularization in ischemic tissues using exogenous agents has become an exciting area of therapeutics. In an attempt to identify novel small molecules with angiogenesis promoting activity, we screened a library of natural products and identified a sulfated steroid, sokotrasterol sulfate, that induces angiogenesis in vitro and in vivo. We show that sokotrasterol sulfate promotes endothelial sprouting in vitro, new blood vessel formation on the chick chorioallantoic membrane, and accelerates angiogenesis and reperfusion in a mouse hindlimb ischemia model. We demonstrate that sulfation of the steroid is critical for promoting angiogenesis, as the desulfated steroid exhibited no endothelial sprouting activity. We thus developed a chemically synthesized sokotrasterol sulfate analog, 2beta,3alpha,6alpha-cholestanetrisulfate, that demonstrated equivalent activity in the hindlimb ischemia model and resulted in the generation of stable vessels that persisted following cessation of therapy. The function of sokotrasterol sulfate was dependent on cyclooxygenase-2 activity and vascular endothelial growth factor induction, as inhibition of either cyclooxygenase-2 or vascular endothelial growth factor blocked angiogenesis. Surface expression of alpha(v)beta(3) integrin was also necessary for function, as neutralization of alpha(v)beta(3) integrin, but not beta(1) integrin, binding abrogated endothelial sprouting and antiapoptotic activity in response to sokotrasterol sulfate. Our findings indicate that sokotrasterol sulfate and its analogs can promote angiogenesis in vitro and in vivo and could potentially be used for promoting neovascularization to relieve the sequelae of vasoocclusive diseases.
authors.affiliation: Department of Medical Biophysics, British Columbia Cancer Agency, 675 West 10th Ave, Vancouver, British Columbia V5Z 1L3, Canada.
authors.forename: Siun
authors.initials: S
authors.lastname: Murphy
authors.forename: Bruno
authors.initials: B
authors.lastname: Larrivée
authors.forename: Ingrid
authors.initials: I
authors.lastname: Pollet
authors.forename: Kyle S
authors.initials: KS
authors.lastname: Craig
authors.forename: David E
authors.initials: DE
authors.lastname: Williams
authors.forename: Xin-Hui
authors.initials: XH
authors.lastname: Huang
authors.forename: Megan
authors.initials: M
authors.lastname: Abbott
authors.forename: Fred
authors.initials: F
authors.lastname: Wong
authors.forename: Cameron
authors.initials: C
authors.lastname: Curtis
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Conrads
authors.forename: Timothy
authors.initials: T
authors.lastname: Veenstra
authors.forename: Mira
authors.initials: M
authors.lastname: Puri
authors.forename: York
authors.initials: Y
authors.lastname: Hsiang
authors.forename: Michel
authors.initials: M
authors.lastname: Roberge
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Andersen
authors.forename: Aly
authors.initials: A
authors.lastname: Karsan
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000494:pharmacology*; D000818:Animals; D002642:Chick Embryo; D002782:Cholestenes / Q000494:pharmacology*; D049033:Chorioallantoic Membrane / Q000098:blood supply; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects; D006614:Hindlimb; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D007511:Ischemia / Q000188:drug therapy; D051379:Mice; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D015424:Reperfusion; D013256:Steroids / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
chemical_list: D043925:Angiogenesis Inducing Agents; D002782:Cholestenes; D039302:Integrin alphaVbeta3; D013256:Steroids; D042461:Vascular Endothelial Growth Factor A; C041016:sokotrasterol sulfate; D051546:Cyclooxygenase 2