July 28, 2005 -- A big breakthrough in tiny technology may soon give doctors the power to deliver a one-two punch to cancerous tumors that knocks out cancer cells without harming the surrounding area.
The anticancer "smart bomb" is based on a new dual-chamber "nanocell" that allows a staged release of two different anticancer drugs. The first shuts down the blood supply and surrounds the tumor while the second, a dose of chemotherapy, kills the imprisoned cancer cells.
"Traditional chemotherapy kills tumor cells directly; some newer drugs work instead by cutting the tumor's blood supply. An innovative approach combines these strategies to pack a double whammy," writes David Mooney, PhD, of Harvard University, in an editorial that accompanies the findings in the current issue of Nature.
Early tests of the strategy in mice showed the combined therapy shrank melanoma and lung cancer tumors and extended the life span of most mice by more than 60 days compared with the 30 days achieved by using either drug alone.
"The effect of the sequential delivery of these two drugs on tumor growth is dramatic, but we cannot assume a quick translation of these results to therapy in humans," says Mooney.
Creating an Anticancer Smart Bomb
The technology combines cancer biology, pharmacology, and engineering, says researcher Ram Sasisekharan, a professor in MIT's biological engineering division, in a news release.
"The fundamental challenges in cancer chemotherapy are its toxicity to healthy cells and drug resistance by cancer cells," says Sasisekharan.
Researchers say the dual-chamber nanocell overcomes these challenges by creating a balloon within a balloon, which effectively drops bombs on cancer cells while cutting the supply lines.
They load the outer membrane of the nanocell with a drug that shuts off blood supply to the tumor and the inner balloon with chemotherapy drugs to destroy cancer cells within the protected area.
Meanwhile, the "stealth" surface of the nanocell allows it to evade the body's natural defenses, the immune system, and enter the tumor directly. The nanocell is designed to be small enough (200 nanometers) to pass through the tumor but too big to enter normal blood vessels.