August 11, 2014 |
Bee, snake or scorpion venom could form the basis of a new generation of cancer-fighting drugs, scientists will report here today. They have devised a method for targeting venom proteins specifically to malignant cells while sparing healthy ones, which reduces or eliminates side effects that the toxins would otherwise cause.
The report was part of the 248th National Meeting of the American Chemical Society (ACS), the world’s largest scientific society. The meeting, attended by thousands of scientists, features nearly 12,000 reports on new advances in science and other topics. It is being held here through Thursday.
“We have safely used venom toxins in tiny nanometer-sized particles to treat breast cancer and melanoma cells in the laboratory,” says Dipanjan Pan, Ph.D., who led the study. “These particles, which are camouflaged from the immune system, take the toxin directly to the cancer cells, sparing normal tissue.”
Venom from snakes, bees and scorpions contains proteins and peptides which, when separated from the other components and tested individually, can attach to cancer cell membranes. That activity could potentially block the growth and spread of the disease, other researchers have reported. Pan and his team say that some of substances found in any of these venoms could be effective anti-tumor agents. But just injecting venoms into a patient would have side effects. Among these could be damage to heart muscle or nerve cells, unwanted clotting or, alternately, bleeding under the skin. So Pan and his team at University of Illinois at Urbana-Champaign set out to solve this problem.
He says that in the honeybee study, his team identified a substance in the venom called melittin that keeps the cancer cells from multiplying. Bees make so little venom that it’s not feasible to extract it and separate out the substance time after time for lab testing or for later clinical use. That’s why they synthesized melittin in the lab.
To figure out how melittin would work inside a nanoparticle, they conducted computational studies. Next, they did the test and injected their synthetic toxin into nanoparticles. “The peptide toxins we made are so tightly packed within the nanoparticle that they don’t leach out when exposed to the bloodstream and cause side effects,” he explains.
What they do is go directly to the tumor, where they bind to cancer stem cells, blocking their growth and spread. He says that synthetic peptides mimicking components from other venoms, such as those from snakes or scorpions, also work well in the nanoparticles as a possible cancer therapy.
Pan says the next step is to examine the new treatment approach in rats and pigs. Eventually, they hope to begin a study involving patients. He estimates that this should be in the next three to five years.