In This Issue
Fishing for Clues to Cancer
Learning how you're put together may help fix what goes wrong, says biologist
BY ANDREW VOWLES
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| Prof. Terry Van Raay, Molecular and Cellular Biology, uses zebrafish to study cellular communication and vertebrate development. Photo by Martin Schwalbe |
If a mechanic didn't know how your car was put together, would you ask him or her to fix it? Not likely, says Prof. Terry Van Raay, Molecular and Cellular Biology (MCB). But that's more or less what happens sometimes when you visit the doctor to repair what ails you, he says.
With disease, we don't always know what's wrong because we hardly know how the body is put together, says Van Raay, a Guelph master's graduate who joined the MCB faculty this summer. He hopes his studies of cellular communication and vertebrate development will help other researchers and doctors better understand diseases such as colorectal cancer.
An estimated 21,500 Canadians will be diagnosed with colorectal cancer in 2008, according to Canadian Cancer Society statistics. Although death rates from this disease are declining, it is still the second most common cause of cancer-related death in men and third in women.
In more than four out of five cases, says Van Raay, the disease results when cellular communication goes awry. Here at Guelph, he is studying the genetics behind the particular cell signalling pathway whose malfunction leads to those cases.
To do that, he's raising a school of zebrafish in the Hagen Aqualab, a couple of buildings south of his new office in the science complex.
Like fruit flies and mice, the zebrafish has become a model organism for researchers. It's small, fast-growing and transparent, making it ideal for many kinds of studies.
Van Raay is interested not so much in the adults as in the youngsters so young that they've hardly become fish at all. It's during the early embryo stage that a pathway called Wnt signalling flickers into life.
The video image on his computer screen shows a translucent ball (the fish's yolk sac) with a cluster of beads the embryo's cells busily multiplying above it. In about six hours, the process reaches gastrulation. During your own development, he explains, that's when you as an embryo laid down three distinct cell layers that eventually formed your insides, your outside and all of your internal organs.
Quoting acclaimed British biologist Lewis Wolpert, Van Raay says: It's not birth, marriage or death but gastrulation that is the most important time in your life.
That process is governed by various chemicals, including Wnt proteins, a family of signalling molecules found in everything from roundworms to humans. By influencing other genes in turn, the Wnt signalling pathway helps establish front and back of the developing embryo and is used over and over for different purposes as the embryo develops. Even in adulthood, the pathway helps generate new tissues such as your gut lining and even your hair follicles.
Genetic defects can derail the process and produce a mutant embryo. Understand a defect, says Van Raay, and we can learn about the gene's normal function.
Besides helping other researchers see the picture more clearly, he hopes to help discover more about disorders caused by defective signalling during this early stage of life. In particular, he says, uncontrolled Wnt signalling can lead to more than 80 per cent of colorectal cancers.
He's also interested in cellular polarity, or how individual cells figure out top from bottom as a young embryo develops. When things go wrong here, other problems may arise, including kidney disease and other genetic disorders such as Bardet-Biedl syndrome.
Growing up near Chatham, Van Raay was always interested in learning how things worked. I liked to take things apart when they were broken, see what was inside and then try to fix them.
He'd considered Guelph for horticulture but studied biology instead at the University of Windsor. He decided to pursue the research path after a stint as a summer technician in the lab of one of his instructors, Prof. Paul Hebert, now a faculty member in U of G's Department of Integrative Biology.
After his undergraduate degree at Windsor, Van Raay transferred to Guelph for his master's when his adviser Prof. Teri Crease, Integrative Biology moved here.
He worked as a research scientist for a biotech company near Boston that was studying kidney disease. That's where his interest was sparked in developmental biology. He first worked on Wnt signalling in frogs during his PhD at the University of Utah, then moved to Vanderbilt University for a post-doc to study the Wnt pathway in zebrafish.
Although Van Raay's interests in the lab focus on the six hours between fertilization and gastrulation, at home he's far more interested in the subsequent development of his own four children, ranging in age from two to nine.