Toxin from salmonid fish has potential to treat cancer

Pathogenic bacteria develop killer machines that work very specifically and highly efficiently. Scientists from the University of Freiburg have solved the molecular mechanism of a fish toxin that could be used in the future as a medication to treat cancer.

The Yersinia species of pathogens can cause the bubonic plague and serious gastrointestinal infections in humans. The pharmacologist Dr. Thomas Jank and his fellow researchers studied a pathogen of the Yersinia family (Yersinia ruckeri). This pathogen causes redmouth disease in Salmonidae, which includes salmon and trout, resulting in large financial losses in the fish industry.

The research group was able to identify a toxin injection machine in the Y. ruckeri genome. The structure of this machine resembles that of viruses that normally attack bacteria. The group demonstrated that the toxin Afp18 in this injection machine is an enzyme that deactivates the switch protein RhoA.

RhoA is responsible for many vital processes in the cells of humans and fish. For example, it controls the building up and breaking down of actin filaments. These filaments are not only necessary for cell division, but also for the spreading of tumour metastases in the body. For this reason, the researchers from the University of Freiburg believe that this fish toxin has great therapeutic potential in cancer treatment.