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5 December 2013 11:26 am ,
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An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Tumor Cells Break Free at Snail's Pace
28 January 2000 7:00 pm
The deadliest tumors seed the body with sloughed cells, which can take root and form new tumors. Researchers have now identified a family of proteins, called Snail, that helps cancer cells pull up stakes. Doctors might one day look for these proteins as warning flags of tumors that are most likely to spread.
Snail isn't all bad. During embryonic development, these proteins direct tissue to turn into mesenchymal cells, such as blood, lymph, or neurons. Now two teams have shown that Snail interferes with the gene for E-cadherin. This protein turns developing tissue into epithelial cells, which pack together tightly to form organs such as the bladder, ovaries, and lungs. E-cadherin is a kind of glue that sticks cells together; tumors with low E-cadherin levels are more likely to spawn tumors elsewhere in the body.
Molecular biologist Antonio García de Herreros of Pompeu Fabra University in Barcelona, Spain, has found that in a line of epithelial tumor cells, Snail binds to a stretch of DNA immediately preceding the E-cadherin gene, thereby gumming up the works and stopping E-cadherin from being produced. Without E-cadherin, the cells are less sticky. The finding suggests that Snail is responsible for the ability of the cancerous epithelial cells to bust out of their interlaced epithelial network and turn into tumors. In separate work, cell biologist M. Angela Nieto and her team at the Institute of Investigative Biomedicine in Madrid tested five mouse and seven human tumor cell lines. The most invasive cells had the most Snail and the least E-cadherin. Moreover, Snail seemed to be turning some cells from tightly packed epithelial cells back into loose mesenchymal cells, those that can break free to form tumors. Both groups describe their work in the February Nature Cell Biology.
The findings are strong evidence that Snail can cut the tether of cancer cells, says cell biologist Barry Gumbiner of Memorial Sloan-Kettering Cancer Center in New York City. Nieto suggests that the presence of Snail in a tumor sample will, like low levels of E-cadherin, alert pathologists that the tumor is likely to spread.