From Venom to Medicine
Researchers at the Max Mousseron Institute of Biomolecules (IBMM) are turning poisons into medicines: they are sifting through animal venoms in search of new therapeutic molecules.
Snakes, scorpions, spiders, cone snails… These animals secrete extremely potent venoms, enabling them to kill their prey in a matter of seconds. But these deadly toxins are also a tremendous source of hope: researchers are studying these venoms to develop new medications. The idea of using animal venoms for medical purposes is not new; snake venom decoctions have been used in traditional Chinese medicine since ancient times. But systematic pharmacological research into these molecules is much more recent.“This field has only been developing intensively for about twenty years,” explains Sébastien Dutertre, a researcher at IBMM.
Poisons that heal
This research has led to the development of new drugs, some of which are now indispensable. Captopril, a drug currently prescribed to thousands of patients with high blood pressure, traces its origins to the fangs of Bothrops jararaca, a fearsome viper found in abundance in Brazil. The venom of this “lancehead viper” is devastating. Researchers discovered that it causes blood vessels to dilate, leading to a drop in blood pressure—a property particularly beneficial for patients with high blood pressure.
Another drug prominently displayed on pharmacy shelves is Byetta, prescribed to patients with type 2 diabetes. The active molecule was identified in the saliva of the “Gila monster,” a Mexican lizard.“Researchers found a molecule there that is similar to insulin but more stable,” explains Sébastien Dutertre. This drug is now prescribed to thousands of diabetics to help them lower their blood sugar levels.
Shellfish that aren't so harmless…
“About twenty molecules derived from animal venoms are already on the market,” explains Sébastien Dutertre. For the past 12 years, the biologist has been studying the venom of cone snails—beautiful tropical shells with colorful patterns that are tempting to pick up as vacation souvenirs, but which turn out to be dangerous predators.“Some of them can even be deadly to humans, such as Conus geographus, which is responsible for numerous accidents,” warns the researcher. These gastropod mollusks are equipped with a harpoon-shaped tooth calleda “radula”that allows them to inject their potent venom to attack prey or defend themselves against predators. In 2004, the first drug derived from cone snail venom was marketed: Ziconotide.
“It’s a painkiller a thousand times more potent than morphine,” notes Sébastien Dutertre, “and it’s particularly useful for patients who have become resistant to conventional opioids.” This discovery spurred research into cone venom, which revealed other particularly interesting properties.“The peptides in these venoms can preferentially target cancer cells, so they could be used as carrier molecules to develop targeted chemotherapies that wouldn’t kill healthy cells,” explains Sébastien Dutertre. Today, the researcher has turned his attention to a local species, the Languedoc scorpion.
A research area that is certainly closer to home, but also completely unexplored:“The pharmacological properties of the molecules that make up its venom have not yet been studied,” explains Sébastien Dutertre. Perhaps a path toward new UM-developed drugs derived from the regional terroir…
Attack or defend—it all depends on the venom
Sébastien Dutertre and his colleagues have shown that cone snails do not use the same weapon for hunting and for defense: they possess two completely different types of venom. This extraordinary ability has been identified for the first time. “We have demonstrated that cone snails only inject their deadly venom when threatened by a predator,” explains Sébastien Dutertre. “When hunting for food, they inject a less complex but highly effective venom to quickly immobilize their prey.” This unique property may be of interest to researchers, particularly in agrochemistry.“Cones feed primarily on small invertebrates such as worms, so we can envision developing products based on their predatory venom that could be used in agriculture to protect plants and crops from attacks by certain worms.”