Spiders and scorpions join fight against superbugs

[August 16, 2016]  By Matthew Stock

(Reuters) - A British lab is searching for new medicines in the poisonous secretions of some of the world's deadliest creatures, addressing the increasingly desperate challenge of finding viable new drugs.

Over-prescription and over-use in farming of antibiotics has given rise to so-called 'superbugs', multi-drug resistant infections that can evade even the medicines designed to kill them. Experts have warned since the 1990s that lethal superbugs were on the horizon, but few drugmakers have attempted to develop drugs against them.

Venomtech, based in south-east England, believe help could be found in the unlikeliest of sources; the venom of spiders, scorpions and snakes that is often fatal to humans. Millions of years of evolution has given these creature's venom the ability to target and attack their prey while avoiding the body's defenses. Venomtech scientists hope that an injected drug could perform the same function.

When broken down at the molecular level a tiny droplet of venom contains hundreds of individual components that could eventually be made into new drugs, explained Venomtech founder Steven Trim.

"The principle of Venomtech is separating venoms out into their component parts and targeting them to the right disease area," Trim told Reuters.

He added that his drug discovery team was "putting the right venom for the right drug target so we maximize the hits - and a hit is an interesting peptide that might make it to a drug."

Around 400 animals are kept at his lab in Kent, including about 70 species of tarantula and 30 species of scorpion. Many of these kill their prey with venoms that contain hundreds of protein molecules, some of which block nerve activity. Venomtech keep a number of invertebrates which can be deadly to humans, namely the black widow spider and deathstalker scorpion.

Trim, who worked for pharmaceutical company Pfizer before founding Venomtech, stressed that the venom extraction process causes no discernible harm to the creatures.

"We anesthetize the invertebrates, just to temporarily put them to sleep, it makes it safer for us because if they're immobile they can't bite us. But also it's better for the animals as well. And using a very tiny electrical stimulation, just to contract the muscle and squeeze the gland we get a small amount of venom produced," he said.

The venom extracted from each creature can be measured in micro-liters; a thousandth of a milliliter. Nevertheless, this tiny volume holds hundreds of useful molecules.

"The average scorpion will only produce 2 or 3 micro-liters. So it's a really small amount. But in that small amount there's a lot of interesting peptides; several hundred different components and several micro-grams of protein in there, so there's plenty for us to work with," Trim said. "We separate that out in a two phase process called high pressure liquid chromatography. And that gives us typically about a hundred fractions per venom, and each one of those fractions may contain 1 to 5 individual peptides. And it's those individual peptides and proteins that are the real interesting things; these are the molecules that convey the biological activity of the venom."

Working with scientists from nearby Canterbury Christ Church University, they've been screening their venom-derived 'chemical library' against different diseases.

Trim said they've had some extremely encouraging results.

"Some of them we found can kill bacteria, bacteria like E.Coli and Staphylococcus, so very relevant at the moment where modern medicines are failing. And we're also finding venoms that are modifying and killing cancer cells," he said, adding that Venomtech is now working with pharmaceutical companies to turn their venom discoveries into the next generation of drugs.

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