Nano 'Basketballs' to Battle Drug-Resistant Cancer

Sept. 24, 2008 -- Drug-resistant bacteria, caused by the over-prescription of powerful antibiotics, is bad enough. Now scientists are identifying the genes responsible for drug-resistant cancers, and finding new ways to stop them.

One group of scientists is developing basketball-shaped nanoparticles that would deliver a punch to cancer cells by interfering with their gene expression. The nanotech-inspired therapies are still at least five years away from use in humans, but according to doctors and scientists, stopping drug resistance, instead of creating new drugs, is an important step that will help save lives.

"Most cancers that can't be removed surgically are already drug-resistant or become drug-resistant," said Michael Gottesman, a doctor at the National Institutes of Health. "But a lot of the literature is focused on finding new anticancer drugs, not worrying about resistance to those drugs."

Gottesman recently discovered that one gene, SIRT1, is responsible for up to 50 percent of Cisplatin-resistant cancers. Cisplatin is a common chemotherapy drug used to treat a range of cancers including testicular, ovarian, bladder and lung cancer.

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Drug-resistant cancers develop much the same way drug-resistant bacteria develop. Treating either bacteria or cancer with conventional drugs might kill 99 of 100 deadly cancer or bacteria cells, but that one cell that survives the initial cull can still create a lethal infection or tumor mass.

Some cancers, like some infectious diseases, even start out resistant to drugs, notes Mansoor Amiji, a cancer researcher at Northeastern University.

"Up to 70 percent of ovarian cancers are initially resistant to the first line chemotherapy," said Amiji. "If that doesn't kill the cancer, 100 percent of those who go into remission will be resistant to those drugs."

When cancer returns, or remits, the patient often has more painful and traumatic chemotherapy and a higher likelihood of not being able to fight off the disease.