Nature, as mesmerizing as it can be, is undeniably hostile. There are endless hazards, both living and nonliving, scattered throughout all parts of the planet. At first glance, the world seems to be quite unwelcoming. Yet through science, humans find ways to survive nature and gain the ability to see its beauty. A fascinating way this is achieved involves taking one deadly element of nature and utilizing it to combat another. In labs and universities across the world today, scientists are fighting one of the world’s most devastating diseases, cancer, with a surprising weapon: animal toxins.
Various scientists around the globe are collecting venomous or poisonous animals and studying the biochemical weapons they synthesize. In their natural forms, these toxins could kill or cause devastating harm to the human body. However, by closely inspecting the chemical properties of these toxins, we have uncovered many potential ways they could help us understand, treat, and cure various diseases. These discoveries have shed a new light on many of the deadly animals we have here on Earth. Mankind may have gained new friends—ones that could be crucial to our survival against cancer and other illnesses.
Take the scorpion, for example. This arachnid exists in hundreds of forms across the globe. Although its stinger is primarily used for killing prey, it is often used for defense against other animals, including humans. Most cases of scorpion stings result in nothing more than pain, swelling, and numbness of the area. However, there are some species of scorpions that are capable of causing more severe symptoms, including death.1 One such species, Leiurus quinquestriatus (more commonly known as the “deathstalker scorpion”), is said to contain some of the most potent venoms on the planet.2 Yet despite its potency, deathstalker venom is a prime target for cancer research. One team of scientists from the University of Washington used the chlorotoxin in the venom to assist in gene therapy (the insertion of genes to fight disease) to combat glioma, a widespread and fatal brain cancer. Chlorotoxin has two important properties that make it effective against fighting glioma. First, it selectively binds to a surface protein found on many tumour cells. Second, chlorotoxin is able to inhibit the spread of tumours by disabling their metastatic ability. The scientists combined the toxin with nanoparticles in order to increase the effectiveness of gene therapy. 3 4
Other scientists found a different way to treat glioma using deathstalker venom. Researchers at the Transmolecular Corporation in Cambridge, Massachusetts produced an artificial version of the venom and attached it to a radioactive form of iodine, I-131. The resultant compound was able to find and kill glioma cells by releasing radiation, most of which was absorbed by the cancerous cells. 5 There are instances of other scorpion species aiding in cancer research as well, such as the Centruroides tecomanus scorpion in Mexico. This species’ toxin contains peptides that have the ability to specifically target lymphoma cells and kill them by damaging their ion channels. The selective nature of the peptides makes them especially useful as a cancer treatment as they leave healthy cells untouched.6
Scorpions have demonstrated tremendous medical potential, but they are far from the only animals that could contribute to the fight against cancer. Another animal that may help us overcome this disease is the wasp. To most people, wasps are nothing more than annoying pests that disturb our outdoor life. Wasps are known for their painful stings, which they use both for defense and for hunting. Yet science has shown that the venom of these insects may have medicinal properties. Researchers from the Institute for Biomedical Research in Barcelona investigated a peptide found in wasp venom for its ability to treat breast cancer. The peptide is able to kill cancer cells by puncturing the cell’s outer wall. In order to make this peptide useful in treatment, it must be able to target cancer cells specifically. Scientists overcame the specificity problem by conjugating the venom peptide with a targeting peptide specific to cancer cells.7 Similar techniques were used in Brazil while scientists of São Paulo State University studied the species Polybia paulista, another organism from the wasp family. This animal’s venom contains MP1, which also serves as a destructive agent of the cell’s plasma membrane. When a cell is healthy, certain components of the membrane should be on the inner side of the membrane, facing the interior of the cell. However, in a cancerous cell, these components, (namely, the phospholipids phosphatidylserine (PS) and phosphatidylethanolamine (PE) ) are on the outer side of the membrane. In a series of simulations, MP1 was observed to selectively and aggressively target membranes that had PS and PE on the outside of the cell. Evidently, using targeted administration of wasp toxins is a viable method to combat cancer.8
Amazingly enough, the list of cancer-fighting animals at our disposal does not end here. One of the most feared creatures on Earth, the snake, is also among the animals under scientific investigation for possible medical breakthroughs. One group of scientists discovered that a compound from the venom of the Southeast Asia pit viper (Calloselasma rhodastoma) binds to a platelet receptor protein called CLEC-2, causing clotting of the blood. A different molecule expressed by cancer cells, podoplanin, binds to CLEC-2 in a manner similar to the snake venom, also causing blood clotting. Why does this matter? In the case of cancer, tumors induce blood clots to protect themselves from the immune system, allowing them to grow freely. They also induce the formation of lymphatic vessels to assist their survival. The interaction between CLEC-2 and podoplanin is vital for for both the formation of these blood clots and lymphatic vessels, and is thus critical to the persistence of tumors. If a drug is developed to inhibit this interaction, it would be very effective in cancer treatment and prevention.9 Research surrounding the snake venom may help us develop such an inhibitor. .
Even though there may be deadly animals roaming the Earth, it is important to remember that they have done more for us than most people realize. So next time you see a scorpion crawling around or a wasp buzzing in the air, react with appreciation, rather than with fear. Looking at our world in this manner will make it seem like a much friendlier place to live.
- Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/scorpion-stings/home/ovc-20252158 (accessed Oct. 29, 2016).
- Lucian K. Ross. Leiurus quinquestriatus (Ehrenberg, 1828). The Scorpion Files, 2008. http://www.ntnu.no/ub/scorpion-files/l_quinquestriatus_info.pdf (accessed Nov. 3, 2016).
- Kievit F.M. et al. ACS Nano, 2010, 4, (8), 4587–4594.
- University of Washington. "Scorpion Venom With Nanoparticles Slows Spread Of Brain Cancer." ScienceDaily. ScienceDaily, 17 April 2009. <www.sciencedaily.com/releases/2009/04/090416133816.htm>.
- Health Physics Society. "Radioactive Scorpion Venom For Fighting Cancer." ScienceDaily. ScienceDaily, 27 June 2006. <www.sciencedaily.com/releases/2006/06/060627174755.htm>.
- Investigación y Desarrollo. "Scorpion venom is toxic to cancer cells." ScienceDaily. ScienceDaily, 27 May 2015. <www.sciencedaily.com/releases/2015/05/150527091547.htm>.
- Moreno M. et al. J Control Release, 2014, 182, 13-21.
- Leite N.B. et al. Biophysical Journal, 2015, 109, (5), 936-947.
- Suzuki-Inoue K. et al. Journal of Biological Chemistry, 2010, 285, 24494-24507.