US Patent Application Paralytic Peptide for use in Neuromuscular Therapy (Stewart et al.)
Spit from poisonous shrew could help with cancer
Canadian Press
Date: Monday Feb. 21, 2005 8:51 AM ET
FREDERICTON — The bad-tempered little shrew has had a well-deserved image problem for centuries, but that may be about to change thanks to its spit.
New research at Mount Allison University in Sackville, N.B., has uncovered enormous medical possibilities in the tiny mouths of the common backyard shrew - one of only two venomous mammals in the world along with the platypus.
Jack Stewart, a biochemistry professor at Mount Allison, and his team of researchers have discovered a compound in shrew spit that holds promise for pain control and cancer treatment.
The substance, a protein Stewart has named soricidin, after the shrew family Soricidae, has been synthesized and is about to be put through intensive animal testing and development.
"We have patents pending and we have synthesized the equivalent of about 40,000 shrew bites," says Stewart.
"Now we're preparing to look further into its properties and develop applications . . . We're talking to a whole bunch of people who are very interested in partnerships and in licensing agreements."
Shrews are ancient mammals with an extremely potent venom delivered along the bottom teeth when biting.
The shy, mouse-like creature with a truncated tail is common throughout eastern North America.
Few people know about the shrew's dark side and the fact that once it bites and paralyzes its prey, it drags the carcass back to its den to munch on at its leisure, while the paralyzed victim is still alive.
"It is gruesome," says Stewart who caught all of his test subjects in the backyard of his Sackville, N.B., home using pepperoni slices as lures.
Other scientists are studying similar paralytic agents in creatures such as scorpions. But Stewart says no other creature has a paralytic venom with such a long-lasting effect - up to 16 days.
These paralytic properties could make soricidin useful in treating migraines, facial pain, neuromuscular diseases, and even wrinkles.
It's possible that at some future date people in search of smooth, youthful skin may be injecting shrew spit instead of Botox.
Stewart says the possibilities don't end with pain and cosmetic treatments. He says it appears soricidin also attacks cancer cells by stopping the development of calcium channels.
"It's an area of study we're actively pursuing," he says.
Stewart says the research has been challenging.
Shrews, cranky creatures whose name has come to represent the sharp-tongued and bad-tempered, are not co-operative when it comes to spitting on demand for scientists.
"You haven't lived until you've washed out a shrew's mouth," says Stewart.
Industry interest in Stewart's shrew research is part of a new trend at Mount Allison, which is positioning itself as the Atlantic hub for biotechnology research and commercialization.
Andrew Paskauskas, director of research development at Mount Allison, says the university is moving away from basic research in favour of international research activities with the potential for wide application.
"We cover a broad spectrum," Paskauskas said. "We're doing work in drug discovery and development, we're doing work in advanced imaging tools based on molecular biology . . . there are a lot of interesting things happening."
The Mount Allison scientists aren't the only ones poking and prodding the mouths of shrews in the name of medical research.
Researchers at Nagoya University in Japan are also exploring the medical possibilities from a toxin found in the shrew's mouth.
Chemistry professor Daisuke Uemura and research associate Masaki Kita recently published a paper on the toxin which they believe may be able to lower blood pressure.
Years later, and the group has formed a private company and could only be a year away from human testing.
Shrew spit tames cancer cells
Last Updated: Monday, May 24, 2010 | 12:55 PM ET
CBC News
Shrew spit is under investigation by Canadian scientists as a potential screening test and treatment for breast, prostate and ovarian cancers.
The northern short-tailed shrew, a mouse-like mammal with a long snout, is one of the world's few venomous mammal species. With one bite, its saliva can paralyze prey.
Biochemist Jack Stewart of Mount Allison University in Sackville, N.B., set out to find out how.
Stewart spent several years luring the animals with pepperoni and trapping dozens of shrews in his rural backyard before he eventually identified the chemical in shrew saliva that causes paralysis. Researchers then purified and synthesized it.
At first, Stewart thought the chemical — called soricidin — might be a potential painkiller, because it blocked nerve transmission. When he tested it on a random cell culture that happened to be ovarian cancer cells, however, he found the cells died — which was initially a source of annoyance to him.
"Then a light bulb came on," Stewart recalled. "Oh, they died," he said with a laugh. "That's a good thing in cancer."
It turned out that soricidin also has an anti-cancer effect against breast and prostate tumours in animal models. It works by blocking calcium from going into the cancer cells.
Like a homing device, soricidin targets a receptor that is found in cancer cells and not healthy cells. That difference makes it a potential diagnostic and treatment tool, said Stewart.
Human trials to come
At a laboratory at the Atlantic Cancer Research Institute in Moncton, Dr. Rodney Ouellette oversees research on a number of potential diagnostic tests for cancer, including soricidin. Ouellette is cautious about raising hopes too early, but he was surprised at early test tube results of the peptide.
"It was a very profound effect on virtually all cancer cell lines we tested," said Ouellette, the institute's president and scientific director. "From that point, we started looking at this in a different way and saying maybe this is the real thing, maybe this can work."
A Phase 1 trial in humans is about a year away, Stewart said. Many research and regulatory hurdles need to be cleared before the peptide could ever be used on patients.
Human studies will determine the peptide could help detect ovarian, breast or prostate cancer cells in a blood test, saliva or urine test, said Ouellette, who has seen many promising molecules fail.
Already soricidin has beaten many odds, however, given that only about one per cent of potential cancer treatments make it to human testing.
Stewart has left his teaching job, and is now the chair and scientific adviser of Soricimed Biopharma Inc., which is hoping to commercialize his discovery to one day detect and treat cancer.
Read more: http://www.cbc.ca/health/story/2010/05/24/shrew-saliva-cancer.html#ixzz19prNsMQa
