Like other ticks, Hyalomma dromedarii—also known as the camel tick—uses compounds in its saliva to fight back host defenses such as clotting and tissue repair. Researchers who have studied tick saliva say those compounds could have beneficial pharmaceutical applications, and a new study shows H. dromedarii saliva exhibits similar antitumor properties as previously found in that of other tick species. (Photo credit: Youmna M’ghirbi, Ph.D.)

Millions of years of evolution have made ticks highly specialized bloodsuckers. In fact, researchers who have studied tick saliva have found a range of compounds that fight back host defenses like clotting and tissue repair and allow ticks to feed for extended periods.

In another context, though, those same chemical properties could be seen in a more positive light: Extracts from saliva of several tick species have been studied for their potential applications in fighting cancer or other conditions. And, in new report published last week in the Journal of Medical Entomology, researchers add saliva compounds from another tick species to the list: Hyalomma dromedarii, also known as the camel tick.

H. dromedarii is common in Africa, the Middle East, and central and southern Asia, and it can often be found on camels, its preferred host. A research team at the Institut Pasteur de Tunis (IPT) in Tunisia says H. dromedarii salivary gland extract inhibits proliferation of a certain type of cancer cell as well as inhibiting angiogenesis, or the formation of new blood vessels.

The researchers, led by IPT’s Chaima Bensaoud, Ph.D., tested the saliva extract’s effect, specifically, on glioblastoma, a fast-growing tumor of the central nervous system, as well as on human umbilical vein endothelial cells, a model for studying angiogenesis. Their study showed that the H. dromedarii saliva extract reduced viability of both kinds of cells after 72 hours, and it also inhibited the cells’ adhesion and migration—in other words, the cells’ ability to attach to a protein that aids in blood-vessel formation, a key step in some tumors’ process of spreading.

“These results open up new possibilities for characterizing and developing new molecules involved in the key steps of tumor progression and angiogenesis,” says IPT’s Youmna M’ghirbi, Ph.D., senior author of the study.

Next up, says M’ghirbi, is parsing the camel tick saliva to identify and test the specific compounds that carry the antitumor and anti-angiogenesis effects. “This field of study is very promising, as the investigations could lead to the discovery of new pharmaceuticals related to hemostasis inflammation and immunity diseases,” she says.