Biologists in Japan have a developed an innovative scanning technique that makes tissues and vital organs transparent, allowing them to track cancer as it spreads throughout the bodies and brains of mice.
The new technique, described in the latest issue of Cell Reports, was developed by researchers from the University of Tokyo and the RIKEN Quantitative Biology Center, and it's allowing scientists to visualise cancer at single-cell resolution. Preexisting scanning techniques have been used to detect and track cancer in living animals before, but not with this level of clarity and microscopic detail.
Using the new technique, the scientists watched cancer cells multiply and spread (that is, metastasise) inside various mouse organs, including the lungs, intestines, liver and brain. Importantly, the researchers were also able to watch anti-cancer medicines combat these pernicious cellular invaders.
This was all made possible by a chemical mixture known as CUBIC, or Clear Unobstructed Brain/Body Imaging Cocktail (what an awesome acronym!). Developed by the RIKEN and University of Tokyo researchers, this mixture makes tissues and vital organs translucent. When used in conjunction with other scanning techniques, such as light-sheet fluorescence microscopy (LSFM) and confocal laser-scanning microscopy (CLSM), it allowed the researchers to detect even the slightest traces of cancer colonies in mice.
The technique was applied to 12 mouse models with nine different cancer cell lines. The researchers used CUBIC to calculate the shapes, volumes, and distributions of various cancerous colonies, and observe cancer cells as they multiplied and spread through the body to form tumours in different areas.
For example, the researchers saw a healthy pair of lungs get colonised by cancer cells in just two weeks. They watched out-of-control pancreatic cells ravage a liver, and then the mouse's entire abdomen. They were even able to pick out individual cancer cells and blood vessels distributed throughout the brain (see the video below).
As a result, the researchers developed a clearer view of how cancer spreads. In order for cancer to reach a new site within the body, it appears that a cancer cell travels through the bloodstream, entering and then exiting through blood vessel walls. The scientists also investigated the effects of anti-cancer drugs in cancer metastasis, providing a unique glimpse of how medicine works inside a live organism.
Further work in this area could yield insights into other cancer and metastatic pathways, and any other health conditions involving single-cell events, such as autoimmune disorders and regenerative medicine.
As for this technique ever being used on live humans, don't hold your breath. The CUBIC compound isn't very human-friendly, requiring a series of genetic modifications. But as a way to peer inside the body of a living creature, it's already proving its worth.