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5 December 2013 11:26 am ,
Vol. 342 ,
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,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
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...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Homing In on Tumors
24 March 2006 (All day)
Researchers have eliminated metastatic cancer in mice by combining the two best candidates yet in a new technique that packs a one-two punch. The result--still a preliminary finding--illustrates the potential for improved cancer treatment through saddling a cancer-killing virus on the back of a tumor-targeting immune cell.
Most current cancer treatments, such as chemotherapy, can't tell healthy cells from cancerous ones. Therapies based on immune cells, which target particular tumor molecules, are more specific, but they are not effective against a variety of tumors. As a result, cancer biologists have turned to a new strategy, known as targeted biological therapy, in which cancer-killing viruses are combined with immune cells. Once the immune cell latches onto a tumor, the virus bursts out and destroys the cancer cells. Finding an immune cell that targets a whole host of tumors and a virus that doesn't release too early, however, has been a challenge.
Now virologists at Stanford University led by Steve Thorne and Christopher Contag have met that challenge by finding the best candidates for the job. First, they identified a type of immune cell, known as a cytokine-induced killer (CIK), that has a taste for many kinds of tumors. Then, for the cargo, they chose the vaccinia virus. Long used as a vaccine for smallpox, vaccinia patiently waits up to 72 hours before busting out. That's enough time for the immune cells to find even the most hidden tumor. In other immune cells, vaccinia goes pop in as little as 4 hours. The team's system has another advantage: CIK cells burrow deep into tumor tissue; that means the virus shouldn't harm surrounding healthy cells.
When the researchers tried the system out in cancer-ridden mice, the CIK cells shot straight for the tumors. Two days after injection, vaccinia was replicating deep inside the tumors and was barely detectable in other parts of the body, the team reports today in Science. Of the eight mice that received this therapy, all completely recovered from their tumors. In a separate group of mice, injecting CIK sans virus only prolonged survival for an extra week; virus alone cured just two out of eight mice tested. That's still a small sample, but this is the first time researchers have managed to create a system like this that works in a clinically relevant setting.
"This is an excellent example of how combination cancer therapies can have additive effects," says Inder Verma, a geneticist at The Salk Institute in San Diego, California. "I think this is the way of future cancer treatments." Even though the Stanford team believes that the vaccinia viruses and the CIK cells are the best available right now, "it is possible that further investigation will produce improvements on this system," says Contag.