Nanotech gene therapy kills ovarian cancer in mice

CHICAGO Thu Jul 30, 2009 1:56pm EDT

A lab mouse is seen in a file photo. REUTERS/File

A lab mouse is seen in a file photo.

Credit: Reuters/File

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CHICAGO (Reuters) - Tiny synthetic particles carrying a payload of toxin worked as well as chemotherapy at killing ovarian cancer cells in mice, without the bad side effects, U.S. researchers said on Thursday.

They said the treatment, which relies on the use of nanotechnology to deliver genetic material into cells, could be ready for human clinical trials in as little as a year.

"What we did was deliver DNA that basically tells cells to die. But it is only turned on in ovarian cells," said Dan Anderson of the Massachusetts Institute of Technology, who worked on the study published in the journal Cancer Research.

If it works, the technology offers promise for a new treatment for ovarian cancer, which kills 15,000 women in the United States each year.

The study highlights the potential of nanotechnology -- the design and manipulation of tiny synthetic particles -- as a non-viral way of getting DNA into cells.

"People have had interesting success with viruses, but viruses have been fraught with certain safety problems," Anderson said in a telephone interview.

His team's solution was to create an "artificial virus" -- a biodegradable polymer that can get inside the cell and be absorbed by the body, in much the same way biodegradable sutures work.

"We think that has got a variety of advantages -- in particular, safety," said Anderson, who worked with a team at the Lankenau Institute in Pennsylvania. "In this case, we show they have potential as therapeutics for ovarian cancer."

The team tested different compounds until they found a biodegradable polymer that would make a suitable delivery vehicle.

To form the nanoparticle, the polymers are mixed with a gene that produces a modified form of the diphtheria toxin that is only harmful to ovarian cancer cells.

"These particles are designed to be eaten by cells and DNA can get released into the nucleus, which is where it needs to be to work," Anderson said.

When they injected the treatment into the abdominal cavity of animals with ovarian cancer, it worked as well or better than the traditional chemotherapy drug combination of cisplatin and paclitaxel, which can cause DNA damage and a variety of side effects.

"We've found these things are at least as efficacious, but are safer," Anderson said.

His team will do several more tests and are fine tuning the manufacturing processes, and they are looking for the right partner to begin studying the treatment in people.

Anderson said the ovarian cancer study is just one demonstration of the potential uses for nanoparticles in non-viral gene therapy. The team plans to study nanoparticle-delivered toxin genes in brain, lung and liver cancers.

The lab also has teamed with biotech firm Alnylam Pharmaceuticals Inc to study the use of nanoparticles to carry treatments in the hot new field of genetic therapy known as RNA interference, which can shut down or silence gene activity.

And MIT is working on nanoparticles as a safer alternative to viruses in making powerful new embryonic-like cells called induced pluripotent stem cells, or iPS cells, Anderson said.

(Editing by Maggie Fox and Eric Walsh)

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