Studying how white blood cells respond to infection has led Michael King to new ways to treat cancer and improve stem cell therapy.

During the six years he spent as a faculty member at the University of Rochester, King led a research group recognized for advancing the understanding of the adhesion cascade, a multi-step process by which white blood cells leave the blood stream.

“When the surrounding tissue is injured or infected, the endothelial cells that line the blood vessels present new proteins on the surface; selectin is the one we study primarily,” explains King. “It can quickly bind to white blood cells as they pass by and cause them to stick.”

The bonds holding the white blood cells last just a millisecond or two. “It’s like a Velcro ball rolling along a Velcro wall,” says King. “This causes white blood cells to patrol the surface looking for the signal that will ‘switch on’ its integrin proteins and cause it to stop. Then it will find a pore in the endothelial layer and squeeze out. That’s how they get out of the blood vessel to gobble up bacteria.”

Selectin is also found in bone marrow blood vessels, where it plays a similar role helping stem cells return from the blood stream. This homing process is what makes bone marrow transplants for leukemia patients possible, and King’s group is developing a device that could make them work even better.

“It’s advantageous to isolate the stem cells that are the most efficient at getting out,” says King. “By flowing them through a micro device with selectin proteins on it, we can purify stem cells before transplanting them.”

Many types of cancer also stick to selectin, which is how they leave the blood stream to metastasize in distant organs. King’s group has invented a microfluidic device coated with selectin, to filter cancer cells from blood, and another naturally occurring protein known as TRAIL, to program the cancer cells to die. “It’s a remarkable thing,” says King. “TRAIL is specific for cancer cells; almost all normal cell types are resistant to it, but all the cancer cell types we’ve worked with are sensitive to it.”

King has already tested an implantable device for stem cell manipulation in rats. A research kit that scientists could use to isolate cancer cells in the lab could hit the market much sooner.

Although he is a scientific adviser for CellTraffix, a New York company with several pending patents based on his work, King says he is more interested in increasing knowledge than commercializing it. “I never set out to make stuff; I just love doing the science,” he says. “The human body always has a deeper mystery to solve. Everything you learn poses a new question.”

Michael King's Web page