Molecular -eat now- signal makes cells devour dying neighbors

A team of researchers has devised a Pac-Man-style power pellet that gets normally mild-mannered cells to gobble up their undesirable neighbors.

The development may point the way to therapies that enlist patients' own cells to better fend off infection and even cancer, the researchers say.

"Our goal is to build artificial cells programmed to eat up dangerous junk in the body, which could be anything from bacteria to the amyloid-beta plaques that cause Alzheimer's to the body's own rogue cancer cells," says Takanari Inoue, Ph.D., an associate professor of cell biology in the Johns Hopkins University School of Medicine's Institute for Basic Biomedical Sciences, who led the study. "By figuring out how to get normally inert cells to recognize and engulf dying cells, we've taken an important step in that direction."

Identifying and devouring dying cells and other "junk" is usually the job of white blood cells called macrophages and neutrophils, which also go after bacteria and other invaders in a process called phagocytosis. For the new experiments, Inoue teamed up with researchers at the University of Tokyo to strip down phagocytosis, figuring out the minimum tools one cell needs to eat another one.

They started not with macrophages, but with a type of laboratory-grown human cells known as HeLa, which normally can't perform phagocytosis.