Although they are single-celled fungi, yeast like this Saccharomyces cerevisiae specimen have genes in common with other, more complex organisms, including humans, by virtue of their shared evolutionary history. For example, yeast have a gene, rab11b, that becomes active when they experience environmental stressors like heat. That gene in yeast, which have no blood, has been repurposed to regulate vein and artery growth in vertebrates like frogs, mice and humans. Scientists studied that gene to find a drug that could keep new blood vessels from forming. Stopping this formation could aid cancer treatments because tumors recruit new blood vessels to feed their growth. In searching for a molecule that would block the yeast gene, the researchers found an unlikely candidate—thiabendazole, an anti-parasitic agent with anti-fungal activity. Following up with more studies, the researchers showed that the compound reduced the growth of blood vessels in frog embryos and inhibited the growth of human blood vessel cells. Thiabendazole also decreased the emergence of new blood vessels and reduced the size of tumors in mice with cancer. In addition to their potential cancer treatment applications, the findings more generally demonstrate the value of an evolutionary approach to drug development. Read more...
Featured in the September 20, 2012, issue of Biomedical Beat.