Repurposing Cancer Drugs Batimastat and Marimastat to Inhibit the Activity of a Group I Metalloprotease from the Venom of the Western Diamondback Rattlesnake, Crotalus atrox

Abstract

Snakebite envenomation causes over 140,000 deaths every year, predominantly in developing countries. As a result, it is one of the most lethal neglected tropical diseases. It is associated with incredibly complex pathophysiology due to the vast number of unique toxins/proteins present in the venoms of diverse snake species found worldwide. Here, we report the purification and functional characteristics of a Group I (PI) metalloprotease (CAMP-2) from the venom of the western diamondback rattlesnake, Crotalus atrox. Its sensitivity to matrix metalloprotease inhibitors (batimastat and marimastat) was established using specific in vitro experiments and in silico molecular docking analysis. CAMP-2 shows high sequence homology to atroxase from the venom of Crotalus atrox and exhibits collagenolytic, fibrinogenolytic and mild haemolytic activities. It exerts a mild inhibitory effect on agonist-induced platelet aggregation in the absence of plasma proteins. Its collagenolytic activity is completely inhibited by batimastat and marimastat. Zinc chloride also inhibits the collagenolytic activity of CAMP-2 by around 75% at 50 μM, while it is partially potentiated by calcium chloride. Molecular docking studies have demonstrated that batimastat and marimastat are able to bind strongly to the active site residues of CAMP-2. This study demonstrates the impact of matrix metalloprotease inhibitors in the modulation of a purified, Group I metalloprotease activities in comparison to the whole venom. By improving our understanding of snake venom metalloproteases and their sensitivity to small molecule inhibitors, we can begin to develop novel and improved treatment strategies for snakebites.

Neutralizing Effects of Small Molecule Inhibitors and Metal Chelators on Coagulopathic Viperinae Snake Venom Toxins

“…The results of this study show that these compounds are capable of neutralizing the coagulopathic activities of individual toxins present in the venoms of a number of Viperinae species. While this is consistent with previous work on small molecule inhibitors and chelators that exhibit anti-hemorrhagic and anti-procoagulant activities of snake venoms [ 9 , 20 , 23 , 42 , 43 , 60 ], here we have studied the relative neutralization potencies of these small molecules on individual coagulopathic venom toxins. Our findings reveal that varespladib is not only effective against the activity of anti-coagulant PLA 2 toxins, but also shows some inhibitory activity against procoagulant venom toxins.…”

“…SVMPs are toxins that are structurally and functionally homologous to matrix metalloproteinses [38][39][40]. Like other compounds in this class of drugs (e.g., batimastat [41]), marimastat is a promising drug candidate for treating snakebite due to its inhibitory capabilities against SVMP toxins [42,43]. Marimastat was found to effectively inhibit the hemorrhagic, coagulant and defibrinogenating effects and proteinase activities induced by Echis ocellatus venom [42].…”

A therapeutic combination of two small molecule toxin inhibitors provides broad preclinical efficacy against viper snakebite

“…Perhaps the most notable of these is the PLA 2 -inhibitor, varespladib, which has been widely explored for repurposing as a snakebite therapy, and has shown substantial promise in preclinical models against a number of elapid and viper venoms 22 , 26 , 27 , 29 . In addition, several SVMP-inhibitors have been demonstrated to be capable of abolishing venom-induced hemorrhage or dermonecrosis, including metal ion chelators 21 , 24 , 25 , 28 and peptidomimetic hydroxamate inhibitors 23 , 24 , 30 . We recently reported that 2,3-dimercapto-1-propanesulfonic acid (DMPS), a Zn 2+ chelator that is a licensed oral medicine used to treat heavy metal poisoning, was particularly effective in preclinically neutralizing both the local and systemic toxicity of Zn 2+ -dependent SVMP-rich saw-scaled viper venoms (genus Echis ) 28 .…”

Exotic Snakebites Reported to Pennsylvania Poison Control Centers: Lessons Learned on the Demographics, Clinical Effects, and Treatment of These Cases

“…PLA 2 s are components of many venoms and produce significant pathological effects. Similarly, batimastat and marimastat are broad-spectrum matrix metalloprotease inhibitors which have been demonstrated to reduce the destructive effects of snake venom metalloproteases (SVMPs) [25,26]. A preliminary report of a combination of varespladib and marimastat, showed promise in an in vivo mouse model of SBE.…”