August 29, 2009
Ticks Spit Could Help Fight Cancer
Though usually considered a parasitic nuisance and a vector for numerous diseases, the tick may actually hold the key for curing skin, liver, and pancreatic cancers, according to new findings from Brazilian researchers.
Proteins were found in the saliva of the common South American tick Amblyomma cajennense, which seems to have the ability to reduce and even completely expunge cancerous cells while leaving healthy cells unharmed.
"This is a radical innovation," said Ana Marisa Chudzinski-Tavassi, the molecular biologist at the Instituto Butantan in Sao Paulo who is leading the research.
"The component of the saliva of this tick... could be the cure for cancer," she told AFP.
She said she discovered the properties of the protein, called Factor X active, by accident. She had set out to test the anti-coagulant properties of the tick's saliva, to see how it keeps the blood from thickening and clotting in order to continue feasting on its host.
This particular protein has some of the same characteristics as a common anti-coagulant called TFPI (Tissue Factor Pathway Inhibitor), more specifically a Kunitz-type inhibitor which has also been found to interfere with cell growth.
The researchers decided to test a theory that the protein might have some effect on cancerous cells, but their laboratory tests on cell cultures came back with results above and beyond what anyone hoped to find.
"To our surprise it didn't kill normal cells, which were also tested," Chudzinski-Tavassi said. "But it did kill the tumorous cells that were being analyzed."
In her lab, she had engorged ticks lined up with straws under their heads to capture their saliva. The small amounts of saliva were reproduced multiple times in yeast vats in order for tests to be performed on cancer ridden lab rats.
What was discovered in that lab has been more than promising, and has given cause to hope for a future cure.
"If I treat every day for 14 days an animal's tumor, a small tumor, this tumor doesn't develop -- it even regresses. The tumor mass shrinks. If I treat for 42 days, you totally eliminate the tumor," the scientist said.
However, years of clinical tests will be required before a subsequent medicine can be produced, and Brazil is not currently ready to provide the substantial financial investment necessary to fund the long term testing.
Chudzinski-Tavassi has applied for a patent on the tick protein, and is now presenting her team's discovery in medical journals and conferences across the globe.
She also said that turning her lab "proof of concept" into a viable cure will be frustrating difficult work.
"To discover this is one thing. To turn it into a medicine is a whole other thing entirely," she said.
Image Courtesy Marcelo de Campos Pereira, University of SÃ£o Paulo
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