Cancer researcher Dr. Cheryl Arrowsmith uses a memorable image to describe what she does.

“Think of cancer as being like a bike. We’re trying to understand what the parts are and how they work, so we can jam a wedge in the spokes. That’s what a drug is.”

The “parts” Dr. Arrowsmith and her colleagues are trying to understand are proteins. These intricately folded chains of molecules account for up to 18 percent of the weight of a healthy adult. The human body can produce as many as a hundred thousand different kinds, and most of our biological processes are the result of a complex balancing act involving interactions between them.

Proteins are manufactured in our cells using instructions encoded in a gene—a section of the cell’s DNA. Damage to a gene can result in the production of too many—or too few—of certain kinds of proteins, or in proteins that are defective. When this happens, the body’s balancing act is thrown off. And when it happens to proteins that are part of the system regulating cell reproduction, the resulting interactions can cause runaway growth—cancer.

Clearly, one possible approach to treating cancer involves intervening in these interactions. And since proteins interact based on their shapes—think about the ins and outs of children’s interlocking plastic blocks—we need to understand their structures.

That’s why creating imagery of proteins related to cancer is a central focus in Dr. Arrowsmith’s lab, a facility funded in part with an investment by the Ontario Innovation Trust. Just as it’s easier to understand how a bicycle works if you have an image rather than a written description of the parts, so it’s easier to grasp how proteins function if you can see their three-dimensional shapes. “If you have a picture of a bike,” explains Dr. Arrowsmith, “you can easily see how you could stick something in the spokes to keep it from moving. In somewhat the same way, visualization helps us understand how proteins interact, and how to block those interactions.”

Dr. Arrowsmith and her colleagues use sophisticated technologies like nuclear magnetic resonance spectroscopy and x-ray crystallography to create the information-rich—and often delightfully colourful—images they need for their research. That information is key to the design of a “wedge in the spokes”—a drug whose molecules “fit” a particular protein, and thereby turn it off or modify its cancer-related behaviour.

The development and testing of such drugs is a long and arduous process, cautions Dr. Arrowsmith. “Clinical trials in the very best of cases take ten years and usually it’s longer than that.” But each new three-dimensional protein portrait represents a crucial first step in a process that may one day stop the grinding wheel of a cancer dead in its tracks.