CC-PLA2-1 and CC-PLA2-2, two Cerastes cerastes venom-derived phospholipases A2, inhibit angiogenesis both in vitro and in vivo

Abstract

Integrins are essential in the complex multistep process of angiogenesis and are thus attractive targets for the development of antiangiogenic therapies. Integrins are antagonized by disintegrins and C-type lectin-like proteins, two protein families from snake venom. Here, we report that CC-PLA2-1 and CC-PLA2-2, two novel secreted phospholipases A 2 (PLA 2 ) isolated from Cerastes cerastes venom, also showed anti-integrin activity. Indeed, both PLA 2 s efficiently inhibited human brain microvascular endothelial cell adhesion and migration to fibrinogen and fibronectin in a dose-dependent manner. Interestingly, we show that this anti-adhesive effect was mediated by a5b1 and av-containing integrins. CC-PLA2s also impaired in vitro human brain microvascular endothelial cell tubulogenesis on Matrigel and showed antiangiogenic activity in vivo in chicken chorioallantoic membrane assay. The complete PLA 2 cDNAs were cloned from a venom gland cDNA library. Mature CC-PLA2-1 and CC-PLA2-2 contain 121 and 120 amino acids, respectively, including 14 cysteines each and showed 83% identity. Tertiary model structures of CC-PLA2-1 and CC-PLA2-2 were generated by homology modeling. This is thus the first study describing an antiangiogenic effect for snake venom PLA 2 s and reporting first clues to their mechanism of action on endothelial cells.

Applications of snake venom components to modulate integrin activities in cell–matrix interactions

“…Mammalian PLA 2 was identified as a ligand for αvβ3 and α4β1 integrins and receptor-binding sites have already been localized (Saegusa et al, 2008). Recent studies revealed that PLA 2 from Cerastes cerastes and Macrovipera lebetina transmediterranea snake venoms also inhibit αvβ3 and α5β1 integrins, although binding sites for these molecules remain unknown (Bazaa et al, 2009; Kessentini-Zouari et al, 2010). …”

Antitumoral Potential of Tunisian Snake Venoms Secreted Phospholipases A2

“…Recently, phospholipases A 2 (PLA 2 s, EC 3.1.1.4) have been demonstrated to modulate integrins which are essential protagonists of the complex multistep process of angiogenesis, the major target for the development of anticancer therapies [21, 27, 28] (Figure 1). …”

“…The most interesting are the antitumor and antiangiogenic activities which involve integrins [27, 28]. …”

“…Since Tunisian phospholipases A 2 are not cytotoxic, it seems that their antitumoral activity is exerted by a different mechanism. Using different assays, such as a solid-phase binding assay and a panel of immobilized antibodies, we have proved that CC-PLA 2 -1, CC-PLA 2 -2, and MVL-PLA 2 inhibit cell adhesion and migration by interacting directly with   α v and   α 5 β 1 integrins [26, 28]. …”

New Insight into the Mechanism of <i>Lonomia obliqua</i> Envenoming: Toxin Involvement and Molecular Approach

“…PLA 2 belongs to a superfamily of enzymes responsible for hydrolyzing the sn -2 fatty acids of membrane phospholipids [70] . These enzymes are known to play multiple roles that include angiogenesis [71] , cell death [72] and inflammation [70] . An experimental model of envenomation in rats has been used to show that a PLA 2 responsible for intravascular hemolysis is present in the venom of L. obliqua [73] .…”