Featured Research

from universities, journals, and other organizations

Ancient Chinese Salad Plant Transformed Into New Cancer-killing Compound

Date:
October 15, 2008
Source:
University of Washington
Summary:
Researchers have updated a traditional Chinese medicine to create a compound that is more than 1,200 times more specific in killing certain kinds of cancer cells than currently available drugs, heralding the possibility of a more effective chemotherapy drug with minimal side effects.

Researchers at the University of Washington have updated a traditional Chinese medicine to create a compound that is more than 1,200 times more specific in killing certain kinds of cancer cells than currently available drugs, heralding the possibility of a more effective chemotherapy drug with minimal side effects.

The new compound puts a novel twist on the common anti-malarial drug artemisinin, which is derived from the sweet wormwood plant (Artemisia annua L). Sweet wormwood has been used in herbal Chinese medicine for at least 2,000 years, and is eaten in salads in some Asian countries.

The scientists attached a chemical homing device to artemisinin that targets the drug selectively to cancer cells, sparing healthy cells. The results were published online Oct. 5 in the journal Cancer Letters.

"The compound is like a special agent planting a bomb inside the cell," said Tomikazu Sasaki, chemistry professor at UW and senior author of the study.

In the study, the UW researchers tested their artemisinin-based compound on human leukemia cells. It was highly selective at killing the cancer cells. The researchers also have preliminary results showing that the compound is similarly selective and effective for human breast and prostate cancer cells, and that it effectively and safely kills breast cancer in rats, Sasaki said.

Cancer drug designers are faced with the unique challenge that cancer cells develop from our own normal cells, meaning that most ways to poison cancer cells also kill healthy cells. Most available chemotherapies are very toxic, destroying one normal cell for every five to 10 cancer cells killed, Sasaki said. This is why chemotherapy's side effects are so devastating, he said.

"Side effects are a major limitation to current chemotherapies," Sasaki said. "Some patients even die from them."

The compound Sasaki and his colleagues developed kills 12,000 cancer cells for every healthy cell, meaning it could be turned into a drug with minimal side effects. A cancer drug with low side effects would be more effective than currently available drugs, since it could be safely taken in higher amounts.

The artemisinin compound takes advantage of cancer cell's high iron levels. Artemisinin is highly toxic in the presence of iron, but harmless otherwise. Cancer cells need a lot of iron to maintain the rapid division necessary for tumor growth.

Since too much free-floating iron is toxic, when cells need iron they construct a special protein signal on their surfaces. The body's machinery then delivers iron, shielded with a protein package, to these signals proteins. The cell then swallows this bundle of iron and proteins.

Artemisinin alone is fairly effective at killing cancer cells. It kills approximately 100 cancer cells for every healthy cell, about ten times better than current chemotherapies. To improve those odds, the researchers added a small chemical tag to artemisinin that sticks to the "iron needed here" protein signal. The cancer cell, unaware of the toxic compound lurking on its surface, waits for the protein machinery to deliver iron molecules and engulfs everything -- iron, proteins and toxic compound.

Once inside the cell, the iron reacts with artemisinin to release poisonous molecules called free radicals. When enough of these free radicals accumulate, the cell dies.

"The compound is like a little bomb-carrying monkey riding on the back of a Trojan horse," said Henry Lai, UW bioengineering professor and co-author of the study.

The compound is so selective for cancer cells partly due to their rapid multiplication, which requires high amounts of iron, and partly because cancer cells are not as good as healthy cells at cleaning up free-floating iron.

"Cancer cells get sloppy at maintaining free iron, so they are more sensitive to artemisinin," Sasaki said.

Cancer cells are already under significant stress from their high iron contents and other imbalances, Sasaki said. Artemisinin tips them over the edge. The compound's modus operandi also means it should be general for almost any cancer, the researchers said.

"Most currently available drugs are targeted to specific cancers," Lai said. "This compound works on a general property of cancer cells, their high iron content."

The compound is currently being licensed by the University of Washington to Artemisia Biomedical Inc., a company Lai, Sasaki and Narendra Singh, UW associate professor of bioengineering, founded in Newcastle, Wash. for development and commercialization. Human trials are at least several years away. Artemisinin is readily available, Sasaki said, and he hopes their compound can eventually be cheaply manufactured to help cancer patients in developing countries.

Other authors of the study are Steve Oh, UW medical student; Byung Ju Kim, UW chemistry instructor; and Singh.

The Washington Technology Center and the Witmer Foundation provided funding for the study.


Story Source:

The above story is based on materials provided by University of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University of Washington. "Ancient Chinese Salad Plant Transformed Into New Cancer-killing Compound." ScienceDaily. ScienceDaily, 15 October 2008. <www.sciencedaily.com/releases/2008/10/081014111309.htm>.
University of Washington. (2008, October 15). Ancient Chinese Salad Plant Transformed Into New Cancer-killing Compound. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2008/10/081014111309.htm
University of Washington. "Ancient Chinese Salad Plant Transformed Into New Cancer-killing Compound." ScienceDaily. www.sciencedaily.com/releases/2008/10/081014111309.htm (accessed October 20, 2014).

Share This



More Health & Medicine News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microneedle Patch Promises Painless Pricks

Microneedle Patch Promises Painless Pricks

Reuters - Innovations Video Online (Oct. 18, 2014) Researchers at The National University of Singapore have invented a new microneedle patch that could offer a faster and less painful delivery of drugs such as insulin and painkillers. Video provided by Reuters
Powered by NewsLook.com
Raw: Nurse Nina Pham Arrives in Maryland

Raw: Nurse Nina Pham Arrives in Maryland

AP (Oct. 17, 2014) The first nurse to be diagnosed with Ebola at a Dallas hospital walked down the stairs of an executive jet into an ambulance at an airport in Frederick, Maryland, on Thursday. Pham will be treated at the National Institutes of Health. (Oct. 16) Video provided by AP
Powered by NewsLook.com
Raw: Cruise Ship Returns to US Over Ebola Fears

Raw: Cruise Ship Returns to US Over Ebola Fears

AP (Oct. 17, 2014) A Caribbean cruise ship carrying a Dallas health care worker who is being monitored for signs of the Ebola virus is heading back to Texas, US, after being refused permission to dock in Cozumel, Mexico. (Oct. 17) Video provided by AP
Powered by NewsLook.com
Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

Spanish Govt: Four Suspected Ebola Cases in Spain Test Negative

AFP (Oct. 17, 2014) All four suspected Ebola cases admitted to hospitals in Spain on Thursday have tested negative for the deadly virus in a first round of tests, the government said Friday. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins