Narrator: This is Science Today. A crucial
piece of the pathway leading to colon cancer has
been identified. Frank McCormick, director of the
University of California, San Francisco's Cancer
Research Institute, found that a protein called
beta catenin, which has long been associated with
colon cancer, directly activates a growth control
protein known as cyclin D1.
McCormick: The way it works is, high levels
of beta catenin accumulate in colon cancer cells.
That protein interacts with a transcription factor
and the transcription factor then turns on production
of new cyclin D1 message and then that leads to
new cyclin D1 protein. So there's the whole chain
- right from the regulator to the control point
to the target gene.
Narrator: Researchers are hoping to inhibit
this process by developing ways to target cyclin
D1 and prevent abnormal cell growth.
McCormick: We need to be sure this is a true
target of this pathway that's relevant in the disease
of cancer - not just in cells in culture. So we
need to do more validation that cyclin D1 is really
responsible for the disease. So, there's some more
experimental work to be done there.
Narrator: For Science Today, I'm Larissa Branin.