by Alison Davis
April 2, 2003

Cells move around constantly in the body. This movement is critical for normal processes like the development of embryos and the proper functioning of the immune system. But since errant cell movement is a feature of many diseases, scientists are working to understand the fundamental--but very complicated--biology of the movement of cells. For example, the transformation of a stationary cell into an invasive one is a crucial step in metastasis, the movement of cancer cells throughout the body. While scientists know a lot about how cancer cells travel through the lymphatic system, little is known about how cells dislodge from an original tumor and move elsewhere in the body.

Using fruit flies as a model system to investigate ovary development, Dr. Denise Montell of The Johns Hopkins University School of Medicine figured out how kickstarting a cell-signaling pathway prompts a group of normally stationary cells lining the ovary to travel in the direction of an oocyte (a future egg). Employing clever tools of genetics, she discovered how three molecules work together to trigger a communication relay called the JAK-STAT pathway. Scientists already knew that this signaling pathway plays a role in controlling cell division and cell survival in both flies and humans, and they knew that the relay system is "on" all the time in many cancers. The new work reveals that the JAK-STAT pathway can also convert cells that were "sitting still" into invasive ones that move around.

Understanding how ovarian cells mobilize in fruit flies may help explain how human tumor cells become metastatic. The research is important in revealing a biochemical basis for a poorly understood step in cancer progression. The scientists are now examining ovarian cancer tissue to see if the JAK-STAT pathway can control the movement of human cancer cells.