Untitled

Abstract

Contortrostatin, a 13.5 kDa disulfide-linked homodimeric polypeptide possessing an Arg-Gly-Asp sequence, was isolated from venom of the southern copperhead snake. Daily injection of contortrostatin into the primary tumor of human breast cancer MDA-MB-435 carried in nude mice significantly inhibited tumor growth and neovascularization of the tumor tissue. On the chick embryo chorioallantoic membrane, contortrostatin inhibited angiogenesis induced by MDA-MB-435 cells, basic fibroblast growth factor, and vascular endothelial growth factor. In addition, contortrostatin effectively blocked adhesion of human umbilical vein endothelial cells (HUVEC) to immobilized vitronectin and significantly inhibited invasion of HUVEC through a Matrigel barrier. Competitive binding assays and adhesion assays with different integrin antibodies suggested that integrin alpha(v)beta3 is a binding site for contortrostatin on vascular endothelial cells. Detachment of HUVEC from vitronectin by contortrostatin induced apoptosis. HUVEC adhered and spread well on immobilized contortrostatin without undergoing apoptosis, suggesting that it is the inhibition of adhesion and spreading of HUVEC on extracellular matrix proteins, rather than binding of contortrostatin to integrins per se, that triggers apoptosis. We conclude that contortrostatin binds to alpha(v)beta3, and interferes with the anchorage-dependent survival mechanism of the vascular endothelial cells, and the mobility of the cells. The consequent suppression of angiogenesis is an important component of the antineoplastic activity of contortrostatin.

Functional Effect of Contortrostatin, a Snake Venom Disintegrin, on Human Glioma Cell Invasion In Vitro

“…CN action includes inhibition of vitronectin/fibronectin-dependent tumor cell adhesion and blockade of tumor cell invasion through a reconstituted basement membrane (Matrigel) (26,56). Furthermore, CN was demonstrated to inhibit growth and dissemination of breast (57) and ovarian (25) cancer in vivo, as well as to block angiogenesis (55). These studies suggest that the vitronectin receptors, αvβ3 and αvβ5, are involved in CN-induced tumor regression.…”

Disintegrins of Crotalus simus tzabcan venom: Isolation, characterization and evaluation of the cytotoxic and anti-adhesion activities of tzabcanin, a new RGD disintegrin

“…Further, disintegrins have received significant attention for their anti-metastatic and anti-angiogenic properties [21e23,26e32] demonstrating their potential applications as an anti-cancer therapeutic. RGD disintegrins such as the homodimeric contortrostatin [21,22,26], and monomeric colombistatin [23], in addition to obtustatin, which contains the sequence KTS in its active site [31,32], have been shown to significantly inhibit experimental metastasis, angiogenesis, and cellular adhesion to specific ECM proteins. The pharmacological potential of these compounds provides a strong motivation to examine snake venoms for novel disintegrins that may have application in biomedical research and drug discovery efforts.…”

Functional characterization of six aspartate (D) recombinant mojastin mutants (r-Moj): A second aspartate amino acid carboxyl to the RGD in r-Moj-D_ peptides is not sufficient to induce apoptosis of SK-Mel-28 cells.

“…Seven disintegrins with a second asparate carboxyl to their RGD induce apoptosis (Ribeiro et al 2014; Minea et al 2010; Seoane et al 2010; Alimenti et al 2004; Hong et al 2003; Brassard et al 1999; Zhou et al 1999; Yeh et al 1998). Therefore, we hypothesized that the second aspartate is sufficient to induce apoptosis.…”

“…Apoptotic-inducing disintegrins with a second aspartate are in two categories: one with an RGDDL and the second with an RGDDM motif. RGDDL disintegrins with reported apoptotic activity include: vicrostatin (Minea et al 2010), salmosin (Hong et al 2003), contortrostatin (Zhou et al 1999), and accutin (Yeh et al 1998). RGDDM disintegrins with reported apoptotic activity include: DisBa-01 (Ribeiro et al 2014), r-Moj-DM (Seoane et al 2010), and echistatin (Alimenti et al 2004; Brassard et al 1999).…”