Deguelin pour le cancer du poumon

Deux articles en anglais au sujet d'un extrait de plante qui préviendrait le cancer du poumon et même feraient mourir les cellules cancéreuses du poumon :

(peut-être que je traduirai plus tard...ou que je trouverai un article en français)


Deguelin, a natural plant product, may interfere with the development of tobacco-induced lung cancer by interfering with the cellular processes that turn normal cells cancerous.

Previous studies have found that deguelin inhibits the proliferation of premalignant and malignant human bronchial epithelial cells by inhibiting the activation of a cellular pathway called P13K/Akt, which helps cancerous cells survive. Ho-Young Lee, Ph.D., of the University of Texas M. D. Anderson Cancer Center in Houston, and colleagues treated mice with deguelin to determine whether deguelin could block tobacco-induced lung tumorigenesis, which occurs through Akt activation.

They found that deguelin decreased Akt activation and the number of tobacco-induced lung tumors in the treated mice compared with untreated mice with no detectable toxicity. The authors conclude that deguelin should be considered for testing as a chemopreventive agent for early stages of lung carcinogenesis.

In an editorial, Stephen S. Hecht, Ph.D., of the University of Minnesota Cancer Center in Minneapolis, points out the difficulties in designing mouse models of tobacco-induced lung carcinogenesis that can then be applied to current and former smokers. That said, he writes, "the work reported by Lee et al., as well as that being carried out in other laboratories, holds some promise for new approaches to lung cancer chemoprevention."

The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage. Visit the Journal online at jncicancerspectrum.oxfordjournals.org.



Plant compound kills lung cancer cells

Last Updated: 2003-02-21 15:40:51 -0400 (Reuters Health)

By Alison McCook

NEW YORK (Reuters Health) - A substance found in plants appears to kill lung cancer cells and prevent healthy lung cells from becoming cancerous, according to laboratory studies.

These findings may lead to new means of preventing people at risk of lung cancer from developing the disease, and of treating them if they do.

If the compound shows itself to be effective and safe in people, it may one day be offered to people at risk of lung cancer, such as smokers, study author Dr. Ho-Young Lee of the University of Texas M.D. Anderson Cancer Center in Houston told Reuters Health.

However, even if the plant extract, known as deguelin, prevents smoking-related cancers with no side effects, Lee cautioned that smoking will never be considered a safe habit.

Smoking can cause many other conditions, she said; a compound that only prevents lung cancer does not give people a free license to smoke.

Drs. James A. Crowell and Vernon E. Steele of the National Cancer Institute, who coauthored an accompanying editorial, added that any treatment involving deguelin, even if possible, is a long ways away.

What is seen in a lab may not be seen in humans, and this study does not guarantee that the substance will eventually keep smokers cancer-free, they told Reuters Health.

The current study "shows that there's promise," and that's all, Steele said.

Deguelin is found in different plant species. In Africa and South America, the substance is often used as an insecticide.

During the current study, published in the Journal of the National Cancer Institute, Lee and her colleagues added deguelin to human cells taken from the inside of the structures leading into the lungs.

The authors found that deguelin both slowed the growth of cancer cells and destroyed healthy cells that were at risk of becoming cancerous, without harming normal cells.

Deguelin appears to inhibit the spread of lung cancer by "dampening the process, and slowing everything down," Crowell said in an interview.

In terms of how deguelin targets cells in danger of becoming cancerous and avoids normal cells, Lee and her colleagues suggest that the plant extract attacks a substance known as Akt that is present at higher levels in precancerous cells than in normal cells.

Lee explained that the next step is to give deguelin to animals at risk of developing lung tumors and see if the compound prevents the disease. Giving deguelin to animals after the tumors have formed will show if the compound can also treat lung cancer, she noted.

If these experiments are a success, further experiments will be needed to determine if deguelin is safe and effective in humans, Lee added.

Crowell and Steele note that investigators may also one day build on the information they have about deguelin and modify the compound into something that is safer and more effective than deguelin itself.

SOURCE: Journal of the National Cancer Institute 2003;95:291-302,252-253.