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Fluorescent Biosensor Lights Up Cancer

Researchers from the Garvan Institute have developed a mouse that expresses a fluorescing biosensor in every cell of its body, allowing diseased cells and drugs to be tracked and evaluated in real time and in three dimensions.

The biosensor mimics the action of a target protein known as Rac, which drives cell movement in many types of cancer. Rac behaves like a switch: when it’s active, the biosensor picks up chemical cues and glows blue. When Rac is inactive the biosensor glows yellow.

Using sophisticated imaging techniques it is possible to follow Rac activation in any organ at any time, or watch moment-by-moment oscillation of Rac activity at the front or back of cells as they move in the body. This technology has been used to monitor Rac activity in many organs in response to drug treatment.

The mouse can be used to study any cancer type by crossing it with other models, limiting the expression of Rac to specific cell or tissue types. The mouse can also easily be adapted to study diseases other than cancer by expressing the biosensor in different disease models.

Dr Paul Timpson, who began the study at the Beatson Institute for Cancer Research in Glasgow and completed it at the Garvan Institute, says that the mouse “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 tumour that is in the process of spreading.

“You can literally watch parts of a tumour 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.”

The research has been published in Cell Reports.