The Department of Biomedicine

Killing cancer with rat poison?

Researchers at the University of Florence had been looking for an new anti-cancer drug, when they realized the old rat poison called Vacor could be the answer to their searches

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Mathias Ziegler, group leader at the Department of Biomedicine, had been visiting Alberto Chiarugi’s lab in Florence during his sabbatical year and participated in this exciting discovery.

“The story behind this article is very interesting”, says co-author Ziegler. “Vacor was used as rat poison in the seventies, but nobody knew how it really worked. Unfortunately, it turned out that it was also toxic for humans. 40 years later, we discovered the mechanism behind it.”

To find new anti-cancer drugs the researchers followed a known strategy, depleting the cancer cells of energy. This can work because cancer cells generally need more energy than healthy cells, since they move, grow, and divide more. The researchers tested chemical compounds that would inhibit enzymatic pathways, so that the cancer cells would have less energy left to survive.

Only, the most promising candidate was not a new discovery, but an old rat poison. It has been known that Vacor was poisonous to both rats and humans, and even the antidote – found empirically many years ago - was known. The antidote was the key to identify the molecular mechanisms of how Vacor kills cells.

Now, we fully understand how it works, why it is toxic to humans, and how we can potentially use it to treat cancer. It turns out that Vacor has great potential, interfering with the metabolic pathways that cancer cells need.

Research at the Department of Biomedicine will continue to explore these pathways.