Cancer 'Smart Bomb' Kills Tumors From Within

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Cancer 'Smart Bomb' Kills Tumors From Within

New Technology Allows Drugs to Seek and Destroy Cancer Cells

By Warner

WebMD Medical News Reviewed By , MD

on Thursday, July 28, 2005

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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 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.

SOURCES: Sengupta, S. Nature, July 28, 2005; vol 436: pp 568-572. News

release, Massachusetts Institute of Technology.