"Minicells" as Targeting Mechanism
Effective per-cell-type targeting of therapies is a fundamental and very important technology platform for the future of medicine. Here's another way of doing it, distinct from methods using viruses or nanoparticles: "The minicells are generated from mutant bacteria which, each time they divide, pinch off small bubbles of cell membrane. The minicells can be loaded with chemicals and coated with antibodies that direct them toward tumor cells. No tumor cell, so far as is known, produces a specific surface molecule for toxins to act on. But 80 percent of solid tumors have their cell surfaces studded with extra-large amounts of the receptor for a particular hormone, known as epidermal growth factor. The minicells can be coated with an antibody that recognizes this receptor, so they are more likely to attach themselves to tumors than to the normal cells of the body. The tumor cells engulf and destroy the minicells, a standard defense against bacteria, and in doing so are exposed to whatever cargo the minicells carry. ... treatment arrested tumor growth in mice implanted with either human colon or human breast tumors, and enabled mice with drug-resistant human uterine tumors to eliminate the tumors altogether."
Link: http://www.nytimes.com/2009/06/29/health/research/29drug.html