News in a nutshell
Pesticides affect children's IQ; questions about how human cancers spread; a promising AIDS trial halted
This week's news includes a link between pesticide exposure and lower IQ in kids, a challenge to a popular cancer metastasis model, discovery of a key melanoma mutations, the failure of an HIV trial, and fighting cancer with counterfeit nabbing nanoparticles.
Prenatal pesticides ding IQ
|Image: Courtesy of USDA|
Unborn children exposed to organophosphate pesticides during gestation suffer IQ deficits as school-aged kids, according to a trio of papers published this week. The three independent studies, which were published today on the website of the journal __Environmental Health Perspectives__, measured the levels of common agricultural pesticides in the bodies of pregnant women and then tracked the cognitive development of their children between 6 and 9 years of age. Each study found, via intelligence tests of the kids, that the women exposed to higher levels of pesticides while pregnant had children with lower IQs. You can read each of the studies at the linkurl:__EHP__ website;http://ehp03.niehs.nih.gov/home.action (linkurl:one;http://ehp03.niehs.nih.gov/article/info:doi/10.1289/ehp.1003183 from the Mount Sinai School of Medicine, linkurl:one;http://ehp03.niehs.nih.gov/article/info:doi/10.1289/ehp.1003160 from the Mailman School of Public Health at Columbia University, and linkurl:one;http://ehp03.niehs.nih.gov/article/info:doi/10.1289/ehp.1003185 from the University of California, Berkeley).
How does your cancer grow?
A promising model for how cancer spreads through the body might be wrong, according to an oncologist who spoke at the recent American Association for Cancer Research meeting. University of California, San Diego, pathologist linkurl:David Tarin;http://pathology.ucsd.edu/faculty/tarin.html shook up the annual AACR meeting by suggesting that tumor cells may not break free and metastasize by reverting back to a mobile cell type present in early embryos. In the epithelial-to-mesenchymal transition (EMT) model, tumor cells metastasize by transitioning from tightly-bound, immobile epithelial-like cells to free floating mesenchymal-like cells that spread through the circulatory system on their way to new organs or tissues, where they revert back to epithelial-like cells and form additional tumors. Tarin said that while the model has been demonstrated in animal models and drug makers are exploring the possibility of inhibiting EMT as a way to fight cancer, the phenomenon has never been observed in humans. See linkurl:__Nature__;http://www.nature.com/news/2011/110419/full/472273a.html for the full story.
Melanoma exome yields key insights
Researchers probing the genome of late-stage melanoma tumors have uncovered suite of a mutations that drives the deadly cancer, including one in a possible novel oncogene. The team, led by scientists at the National Institutes of Health, found mutations in the exact same position within the __TRRAP__ gene in six out of 167 melanoma patients. They also found a mutation in a previously unidentified gene, __GRIN2A__, in 33 percent of the melanoma samples they sequenced. The linkurl:paper;http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.810.html was published online last week in __Nature Genetics__. For more on cutting edge melanoma research, check out __The Scientist__'s April linkurl:cover story.;http://www.the-scientist.com/2011/4/1/32/1/
Promising HIV trial shut down
A study testing the ability of antiretroviral drugs to prevent HIV infection in thousands of African women has been halted after 56 volunteers came down with the disease. An analysis of preliminary results indicated that there was no difference in HIV infection rates between patients treated with Truvada, a combination drug that contains two antiretroviral compounds, and patients given a placebo. The study tracked women at a high risk of infection via heterosexual sex. Previous studies seeking to head off HIV infection with antiretroviral drugs had produced promising results, especially one that found an anti-HIV pill effective in preventing infection among men who have sex with men. (Hat tip to __ScienceInsider__
How phony Benjamins are like early tumors
The same nanoparticles that help authorities nab currency counterfeiters may one day help doctors detect colorectal cancer earlier, according to a new study in mice. Researchers from Stanford University and the University of Cambridge administered gold-silica nanoparticles, which are embedded in currencies to help authenticate bills, labeled with molecules that bind to epidermal growth factor receptors within early-stage colorectal polyps to mice. The compound was essentially non-toxic and improved the ability to image small or flat polyps that occur at the onset of colorectal cancer and are commonly missed in traditional endoscopy, according to the linkurl:paper;http://stm.sciencemag.org/content/3/79/79ra33.abstract published this week in __Science Translational Medicine__.
**__Related stories:__***linkurl:Taking Aim at Melanoma;http://www.the-scientist.com/2011/4/1/32/1/
[April 2011]*linkurl:Imagining a Cure;http://www.the-scientist.com/article/display/58067/
[April 2011]*linkurl:New metastasis marker found;http://www.the-scientist.com/news/display/57970/