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Posted on Jan 15, 2007, 5 a.m.
By Bill Freeman
Associate Professor Michael King of the University of Rochester Biomedical Engineering Department has invented a device that filters the blood for cancer and stem cells. When he captures cancer cells, he kills them. When he captures stem cells, he harvests them for later use in tissue engineering, bone marrow transplants, and other applications that treat human disease and improve health.
Associate Professor Michael King of the University of Rochester Biomedical Engineering Department has invented a device that filters the blood for cancer and stem cells. When he captures cancer cells, he kills them. When he captures stem cells, he harvests them for later use in tissue engineering, bone marrow transplants, and other applications that treat human disease and improve health.
With Nichola Charles, Jared Kanofsky, and Jane L. Liesveld of the University of Rochester, King wrote about his discoveries in "Using Protein-Functionalized Microchannels for Stem Cell Separation," Paper No. ICNMM2006-96228, Proceedings of the ASME, June 2006. King’s team includes scientists at StemCapture, Inc., a Rochester company that bought the University patent for King’s technique in November 2005 to build the cancer-killing and stem cell-harvesting devices. The technique can be used in vivo, meaning a device is inserted in the body, or in vitro, in which case the device resides outside of the body – either way, the device kills cancer cells and captures stem cells, which grow into blood cells, bone, cartilage, and fat.
When King was working at the University of Pennsylvania from 1999 to 2001, one of his labmates discovered that bone marrow stem cells stick to adhesive proteins called selectins more strongly than other cells -- including blood cells -- stick to selectins. When King came to the University of Rochester in early 2002, he started studying the adhesion of blood cells to the vascular wall, the inner lining of the blood vessels. During inflammation, the vascular wall presents surface selectins that adhere specifically to white blood cells. These selectins cause the white blood cells to roll slowly along the vascular wall, seeking signals that tell them to crawl out of the bloodstream. This is how white blood cells migrate to bacterial infections and tissue injuries. King set out to find a way to duplicate this natural process.
First, he noted that the selectins form bonds with the white blood cells within fractions of a second, then immediately release the cells back into the bloodstream. He also realized that selectin is the adhesive mechanism by which bone marrow stem cells leave the bloodstream and find their way back into bone marrow. This is how bone marrow transplantation works. Finally, he learned that when a cancer cell breaks free of a primary tumor and enters circulation, it flow through the bloodstream to a remote organ, then leaves the bloodstream and forms a secondary tumor. This is how cancer spreads. He put these facts together with one more, very important fact: the selectins grab onto a specific carbohydrate on the surfaces of white blood cells, stem cells, and cancer cells. Associate Professor King decided to capture stem and cancer cells before the selectins release them.
