Friday, August 05, 2005

MIT Devises Cancer Smart Bomb

As long as these anti-cancer terrorbots use their powers for good and not evil...

Imagine a cancer drug that can burrow into a tumor, seal the exits and detonate a lethal dose of anti-cancer toxins, all while leaving healthy cells unscathed.

MIT researchers have designed a nanoparticle to do just that.

The dual-chamber, double-acting, drug-packing "nanocell" proved effective and safe, with prolonged survival, against two distinct forms of cancers-melanoma and Lewis lung cancer-in mice.

The team loaded the outer membrane of the nanocell with an anti-angiogenic drug and the inner balloon with chemotherapy agents. A "stealth" surface chemistry allows the nanocells to evade the immune system, while their size (200 nanometers) makes them preferentially taken into the tumor. They are small enough to pass through tumor vessels, but too large for the pores of normal vessels.

Once the nanocell is inside the tumor, its outer membrane disintegrates, rapidly deploying the anti-angiogenic drug. The blood vessels feeding the tumor then collapse, trapping the loaded nanoparticle in the tumor, where it slowly releases the chemotherapy.

The team tested this model in mice. The double-loaded nanocell shrank the tumor, stopped angiogenesis and avoided systemic toxicity much better than other treatment and delivery variations.

But it is patient survival and quality of life that really inspire this research, Sasisekharan said. Eighty percent of the nanocell mice survived beyond 65 days, while mice treated with the best current therapy survived 30 days. Untreated animals died at 20.

The nanocell worked better against melanoma than lung cancer, indicating the need to tweak the design for different cancers.