This led Professor Henry Lai and his colleague Narendra Singh of the University of Washington on the idea of testing the substance, even when the cancer treatment. Even cancer cells have a much higher iron content than healthy cells. This fact was supported by researchers in the cancer cells beforehand, they also injects iron. The subsequent treatment of cancer with artemisinin in vitro showed significant effects: After eight hours three quarters of the cancer cells were destroyed, 16 hours later, nearly all cancer cells had died, the majority of the dead, but not from healthy cells. Importantly, in these experiments was also used in an experiment that breast cancer cells that had not previously responded to radiation treatment, but sensitive by artemisinin reacted.
This means that a cancer treatment with artemisinin could be successful even in cancers for which conventional therapies have not been struck.
From Idea to Treatment
For more aggressive cancers such as pancreatic and acute leukemia, the test results are very promising. These cancers are characterized by an extremely rapid cell division and thus by an even higher iron concentrations. Recent studies have shown that artemisinin also takes effect on neoangiogenesis. This means that the substance could potentially prevent the tumor creates new ways in the body and can form metastases.
As part of a complementary tumor therapy for cancer patients are now treated for a week with an iron resources. After 3 to 6 milligrams per kilogram of body weight will be given to artemisinin. After six weeks the re-priming takes place with iron, then again a six-week administration of Artemisisin.
Artemisinin is selectively kill cancer cells while normal cells unharmed
University of Washington
Researchers at the University of Washington have blended the past with the present in the fight against cancer, synthesis of a promising new compound from an ancient Chinese medicine, the cancer cells’ rapacious appetite for iron, so that they target.
The substance, artemisinin, is derived from the wormwood plant and has been in China since ancient times to treat malaria. Earlier work by Henry Lai and Narendra Singh, both UW Bioengineering indicated that artemisinin alone could selectively kill cancer cells, while normal cells unharmed.
The new compound appears to improve significantly, that the deadly selectivity, according to a new study in a recent issue of the journal Life Sciences. In addition to Lai and Singh, co-authors include Tomikazu Sasaki and Archna Messay, both UW chemists.
"By itself, artemisinin is about 100 times more selective in killing cancer cells, unlike normal cells," Lai said. "In this study, the new artemisinin compound was 34,000 times more potent in killing cancer cells, unlike their normal cousins. Thus, the tagging is seems to have greatly increased the effectiveness of artemisinin to cancer-killing properties."
The substance was being developed under license to Chongqing Holley Holdings and Holley Pharmaceuticals, its U.S. subsidiary, for possible use in humans. Although the compound is promising, say the officials, possible use for humans is still years away.
In the study, the researchers exposed human leukemia cells and white blood cells to the substance. While the leukemia cells quickly died, the white blood cells remained essentially unharmed.
The trick to the compound of effectiveness, according to Lai seems, in the use of the function, such as cancer cells.
Because they multiply so quickly that most cancer cells need more iron than normal cells, DNA replication. To facilitate that, cancer cells have inlets on their surface, also known as transferrin receptors, in which more than other cells. These receptors allow quick transport into the cell of transferrin, an iron-protein found in the blood.
In preparing the compound, researchers bound artemisinin to transferrin at the molecular level. The combination of the two components is a fool the cancer cell.
"We call it a Trojan horse because the cancer cell recognizes transferrin as a natural, harmless protein," Lai said. "So the cell is the connection, not knowing that a bomb - artemisinin hidden - on the inside."
Once inside the cell, the artemisinin reacts with the iron, spawning highly reactive chemicals called "free radicals". The attack of free radicals and other molecules in the cell membrane, breaking it apart and killing the cell.
According to Lai, that process is what initially piqued his interest in artemisinin over 10 years. The wormwood extract was lost centuries ago in China, but the treatment was over time. In the 1970s it was again as part of an ancient manuscript that medical measures, including a recipe, a wormwood extract. The medical community soon discovered that the extract, artemisinin, good against malaria, and it is currently available for this purpose in all of Asia and Africa.
Artemisinin against malaria because the malaria parasite collects high iron concentrations, as they metabolized hemoglobin in the blood. As science began to understand how artemisinin worked, Lai said he began to wonder if the process had implications for cancer treatment.
"I think that maybe we can use this knowledge to selectively target cancer cells," he said. "So far, the outlook seems to be good.
Artemisinin is a secondary plant substance, Chemically sesquiterpene that occurs in the leaves and flowers of the sweet wormwood (Artemisia annua). Characteristics of Artemisininstruktur are a Trioxanringsystem and Peroxidbrücke. It is used in Vietnam, China and Africa used to treat infections with multidrug-resistant strains of Plasmodium falciparum, the causative agent of malaria tropica. In June 2009, however, were known from Cambodia, the first cases of resistance.
The extraction is carried through the extraction of dried leaves and flowers with hexane, which is the active ingredient, which is predominantly localized in the ethereal öldrüsenschuppen, readily soluble. On an area of one hectare can be harvested up to two tons of sheet material to provide two to three kilograms of the extract. The Artemisiningehalt in the plant is between 0.1 and 0.4% dry weight. Engineered with an active substance content of up to 1.4% are known. From the concentrated crude extract, a yellow, viscous oil, artemisinin is obtained by recrystallization, but this method is relatively expensive and, consequently, the price of artemisinin is very high.
Experimentally, more recently, the biosynthesis in genetically modified E. coli bacteria and Saccharomyces cerevisiae explored. The first successes on the way to artificial substitutes already exist. Jay Keasling it is supported by the Bill and Melinda Gates Foundation, with 43 million U.S. dollars.