1 July 2014

Antihistamines may be next blockbuster anti-cancer drug

by Will Parker

Scientists have established a connection between two diseases that aren't commonly linked: allergy and cancer. The new research, published in the The Journal of Leukocyte Biology, shows that antihistamines appear to have "significant" anti-cancer properties. Specifically, antihistamines were found to interfere with the activity of myeloid derived suppressor cells, which are known to reduce the body's ability to fight tumors.

To make the discovery, researcher Daniel H. Conrad (Virginia Commonwealth University) and colleagues worked with two groups of mice. The first group of mice was infected with rodent intestinal helminths to stimulate a strong allergic response. Then they were injected with myeloid derived suppressor cells and treated with anti-histamines (cetirizine or cimetidine). Conrad said the treatment with anti-histamines reversed the effects of the myeloid derived suppressor cells.

The second group of mice had tumors and were injected with myeloid derived suppressor cells and treated with the antihistamine, cimetidine. In this group, the antihistamine also reversed the enhanced tumor growth normally seen with myeloid derived suppressor cell injection.

Finally, the scientists examined blood from humans with allergy symptoms (typically associated with increased histamine release). The scientists found that these patients had increased circulating myeloid derived suppressor cells over non-allergic controls.

"This research is very exciting," said Conrad, "[but] it's important to realize that this connection is very novel and more research is needed before we know if antihistamines can be used effectively in cancer therapies."

"We still have much to learn about their potential benefits," added John Wherry, Deputy Editor of the Journal of Leukocyte Biology. "It is certainly not yet time to prophylactically administer antihistamines for cancer prevention, but the more we learn about myeloid derived suppressor cells, the more interesting these cells and their products become as immunotherapy targets in cancer. These new results suggest that we must be open-minded about seemingly distantly related immune mechanisms."

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Source: Federation of American Societies for Experimental Biology