Mouse's Glowing Cells Enable Minute-by-Minute Cancer Tracking

A mouse engineered so that every cell in its body glows with biofluorescence has enabled scientists to track and evaluate diseases in real time and in three dimensions, according to a new report in the journal Cell Reports.

The mouse's cells glow blue and yellow thanks to a biosensor installed the mouse that mimics the action of a protein molecule known as Rac, a driver of cell movement in many types of cancer. The Rac protein can either be active or inactive.

When the Rac is active, the biosensor picks up the chemical trace and the mouse's cells glow blue, when Rac is inactive the cells glow yellow. By performing an imaging operation on the mouse, it is possible for researchers to see the biosensor activate and trigger a color change in the cells in any organ at any time. Scientists can also observe the moment-by-moment oscillation of Rac activity at the front of back of cells as they move through the body.

"The great thing about this mouse is its flexibility and potential for looking at a broad range of diseases and molecular targets," said Paul Timpson, of Sydney's Garvan Institute of Medical Research, who participated in the research. "It allows us to watch and map, in real time, parts of a cell or organ where Rac is active and driving invasion. In cancers, a lot of blue indicates an aggressive tumor that is in the process of spreading."

"You can literally watch parts of a tumor turn from blue to yellow as a drug hits its target. This can be an hour or more after the drug is administered, and the effect can wane quickly or slowly. Drug companies need to know these details -- specifically how much, how often and how long to administer drugs," Timpson said in a news release.

The biosensor is a single molecule probe called Raichu-Rac, which was invented in 2002 by Japanese scientist Miki Matsuda.

The researchers credited Matsuda's invention, and that he made it freely available to the scientific community, for their successful project.

"Miki Matsuda was super-helpful in suggesting the expression levels we should be looking for, and in recommending the exact biosensor we should use, out of many he developed," said Heidi Welch from the Babraham Institute in Cambridge, who created the mouse.

"The credit must go to Professor Miki Matsuda, the genius who invented the biosensor in the first place 12 years ago," she said.