An active substance known to researchers for 30 years can turn into a ray of hope against eye tumors, shows a study conducted at the universities of Bonn and Magdeburg.
A press statement states that the substance is found in coralberry, a plant widely used as part of Christmas decorations. “The plant, originally from Korea, is surprisingly resistant to insect attack: Its leaves contain bacteria that produce a natural insecticide – a toxin with the cryptic name FR900359, abbreviated FR.”
The statement mentions that this toxin could soon be used as a potential drug against uveal melanoma, the most common and aggressive variant of eye cancer.
“The substance inhibits an important group of molecules in the cells, the Gq proteins,” Prof. Dr. Evi Kostenis from the Institute of Pharmaceutical Biology at the University of Bonn has been quoted as saying in the statement.
The statement explains that the Gq proteins have a similar function in the cell as a city’s emergency control center: When the control center receives a call, it informs the police, ambulance and fire brigade as required. Gq proteins, on the other hand, can be activated by certain control signals. In their activated form, they switch different metabolic pathways on or off. However, the cell should not permanently change its behavior. The Gq proteins, therefore, inactivate themselves after a short time.
“In uveal melanoma, however, a tiny mutation prevents two important Gq proteins from returning to their inactive state. They thus remain permanently active – this is as if the control center were constantly sending emergency vehicles to the source of the fire, even though the fire has been extinguished for days. Due to this malfunction, cells harboring this mutation begin to divide uncontrollably,” it says.
FR can stop this division activity
Another researcher who worked on the project, Dr. Evelyn Gaffal, had recently moved from Bonn to the University of Magdeburg, where she’s also working on skin cancer. She was quoted in the statement as saying, “We also used FR in our experiments and were surprised to find that it suppresses the proliferation of cancer cells.”
Scientists now also know why this is so: The mutated Gq proteins also seem to occasionally revert into their inactive form. As soon as this happens, FR900359 intervenes and gets a firm grip on the molecule. As a result, over time, more and more Gq proteins are successively withdrawn from their activated state for good.
FR has already proven its effectiveness in cell cultures and in experiments with mice suffering from cancer. But there are still a few hurdles to overcome before application in humans becomes feasible. Above all, the substance must reach the tumor cells precisely, without hitting other tissues. “Gq proteins assume vital functions practically everywhere in the body,” explains Prof. Kostenis. “If we want FR to kill only the tumor cells, we have to get the drug right there. However, this is a challenge that many other chemotherapies also have to deal with.”