Normal cells (left) have far more sugar attached to mucins than do cancerous cells (right). Mucin-attached sugar generates a high MRI signal, shown in red.
Image credit: Johns Hopkins Medicine
Previous studies have found that fine-tuned magnetic resonance imaging (MRI) can detect glucose based on the way it interacts with surrounding water molecules. Although techniques to identify glucose had previously been in use in this way, scientists were required to use injectable dyes in order to image proteins on the outside of cells that lost sugar.
In the new study - published in the journal Nature Communications - the Johns Hopkins team compared MRI readings from proteins - called mucins - with and without sugars to look for any changes in signal. They then looked for this signal in four types of lab-grown cancer cells. Among the cancer cells, they found markedly lower levels of mucin-attached sugars than in normal cells.
"We think this is the first time scientists have found a use in imaging cellular slime," says Jeff Bulte, PhD, a professor of radiology and radiological science in the Institute for Cell Engineering at the Johns Hopkins University School of Medicine.
"As cells become cancerous, some proteins on their outer membranes shed sugar molecules and become less slimy," he explains, "perhaps because they're crowded closer together. If we tune the MRI to detect sugars attached to a particular protein, we can see the difference between normal and cancerous cells."
Entire tumor could be imaged by detecting molecule already inside the body
"The advantage of detecting a molecule already inside the body is that we can potentially image the entire tumor," says Xiaolei Song, PhD, the lead author on the study and a research associate in Bulte's laboratory. "This often isn't possible with injected dyes because they only reach part of the tumor. Plus, the dyes are expensive."
So far the technique has only been used in lab-grown cells and mice. More testing is required to demonstrate the technique's value in human cancer diagnosis. The next step for the team will be to attempt to distinguish cancerous from benign tumors in live mice.
If these tests are successful, the researchers believe that the technique could be used to detect early-stage cancer or monitor chemotherapy response. The method may also be useful for ensuring that biopsies sample the most malignant part of a tumor - therefore making some biopsies unnecessary.
Elsewhere on Medical News Today, we look at a study presented at the 249th National Meeting & Exposition of the American Chemical Society (ACS) that suggests saccharin - commonly found in sugar-free sweeteners - could be used to treat aggressive cancers.