Brazilian researchers from Rio de Janeiro's Federal University's (UFRJ) Haemostasis and Poisons Laboratory found out that a protein isolated from the star tick, also known as horse tick (Amblyomma cajennense)Â works to fight the aggressive skin cancer melanoma as well as glioblastoma, a malignant tumor mostly found in the brain.
The protein called Ixolaris managed to reduce in mice, in some cases, by 80% the two kinds of tumors. Mice treated for 42 days with the protein saw their tumors entirely disappear. Since 2004 the groups studying the star tick have applied for a patent to the National Industrial Property Institute (INPI) in the United States.
The star tick is known as the cause of maculose fever, an often fatal disease, which is transmitted by the sting of the arachnid.
José Marcos Ribeiro and Ivo Francischetti, two Brazilian scientists who now work at the US's National Institute of Health (NIH), were the first to isolate the Ixolaris. They count these days on the collaboration of another Brazilian researcher, Robson Monteiro from the UFRJ's lab.
Monteiro and his team showed that injected in mice, the tick protein links to Factor ten, a plasma protein responsible for blood coagulation. Such a linkage does not only helps to regulate coagulation but also the growth of cancerous tumors.
According to the professor, most patients with cancer have an unbalance in their coagulation process and the formation of blood clots are common due apparently to the tumor's aggressiveness. Ixolaris, he says, inhibits not only coagulation but also the development of the malignant tumor.
In the trials held by the Brazilian scientists five to ten mice were used. Animals with melanoma were administered the protein for 15 days, those with glioblastoma had the treatment for a whole month. The substance was injected subcutaneously, opening the door for self medication in case the treatment is proved to be effective for humans.
The UFRJ study has now being extended to other places besides the US's National Institute of Health. In São Paulo, scientists from USP (University of São Paulo) are doing the same line of research and in Rio at Fiocruz, other researchers are also examining what's involved in the shrinking of the tumors.
The next step, according to Monteiro, is to have clinical tests in humans. This will not be possible, however, before the group can find a biotechnology company willing to be a partner and produce the Ixolaris substance in semi-industrial scale.
A not-yet published study on the properties of the tick for treating cancer was presented last July in the United States, during the XXII Congress of the International Society on Thrombosis and Haemostasis, held in Boston.
"We figured that the tick saliva had some component that inhibits coagulation, because, as hematophagous, it needs to keep the blood flowing to feed itself," says Ana Marisa Chudzinski-Tavassi, a pharmacist who coordinated the study.
The laboratories BioLab, Aché and União Química have formed a consortium for future medications that might arise from the discovery. Chudzinski-Tavassi, however, has some misgivings. She fears bureaucracy will prevent her and her colleagues from advancing their work.
Talking about the São Paulo Butantan laboratory for which she works, the scientist comments:Â "The Institute Butantan does not have autonomy to sign patents and the bureaucratic process takes a long time. On the other hand, the industry questions the wisdom of investing in something that does not offer juridical security."
