Mayo Clinic researchers discover and manipulate molecular interplay that moves ca...( JACKSONVILLE Fla. Based on research...)

JACKSONVILLE, Fla. Based on research that reveals new insight into mechanisms that allow invasive tumor cells to move, researchers at the Mayo Clinic campus in Florida have a new understanding about how to stop cancer from spreading. A cancer that spreads elsewhere in the body, known as metastasis, is the process that most often leads to death from the disease.

In the March 29 online issue of Nature Cell Biology, researchers say that a molecule known as protein kinase D1 (PKD1) is key to the ability of a tumor cell to "remodel" its structure, enabling it to migrate and invade. The researchers found that if PKD1 is active, tumor cells cannot move, a finding they say explains why PKD1 is silenced in some invasive cancers.

During metastasis, invasive cancer cells respond to biological signals to move away from a primary tumor. Multiple research groups at Mayo Clinic in Florida are especially interested in this process. One team, led by cancer biologist Peter Storz, Ph.D., has been investigating a process known as actin remodeling at the leading edge - the most forward point - of these migrating tumor cells.

"The events that reorganize the actin cytoskeleton at the leading edge are complex a multitude of molecules act in concert," Dr. Storz says. "But it appears that PKD1 must be turned off if cancer cells are to migrate."

Actin filaments help make up the cytoskeleton of cells. For cancer cells to move, the actin-based cell structure has to be continually reorganized, Dr. Storz says, and to do this, new actin filaments need to be generated to shift the cell forward.

Dr. Storz' group discovered that PKD1 was critical to this process. The researchers found that PKD1 inhibits another protein known as slingshot, which regulates the severing of existing actin structures so that new actin filaments can be synthesized, an event that is essential for cell movement.

The researchers used methods to deplete tumo
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