Cancer protein chops cell anchors

Matrix metalloproteinases (MMPs) act like machetes in a forest: they clear a path to allow cell movement. Now researchers have found that they also chop up the proteins that keep cells anchored in place, thus dislodging cancer cells and allowing them to move around the body.

Motoharu Seiki (University of Tokyo, Japan) and colleagues report in the May 28 issue of The Journal of Cell Biology that a protein called CD44, found on many cancer cells, attaches to an abundant protein outside of the cell called hyaluronic acid (HA). This gives the cells a positive signal that is necessary for movement. But for the cells to get moving they must break this connection. This is where membrane-type 1 MMP (MT1-MMP) comes in. It is made by the cancer cells, and it cuts the CD44, allowing the cells to detach from the HA and break free. Movement allows the cancer cells to form metastases in other part of the body.

Contact: Motoharu Seiki, Department of Cancer Cell Research, Institute of Medical Science, University of Tokyo, Japan; 81-3-5449-5255; mseiki@ims.u-tokyo.ac.jp