A new study in Nature sheds light on the last-ditch efforts of yeast cells to evolve rapid drug resistance, reports New Scientist's Andy Coghlan, a discovery which may have implications for how cancer is treated. When yeast cells are stressed by a stimulus, they "frantically reshuffle their chromosomes in a desperate last bid to find a combination that survives," Coghlan says — this "panic" response allows for rapid evolution to resist the stimulus. In the study, researchers from the Stowers Institute for Medical Research exposed Saccharomyces cerevisiae to various heat and chemical stimulants. They found that when heat-shock protein 90 was disrupted in yeast, the cells lost or duplicated chromosomes randomly when they divided, leading to colonies of drug-resistant cells, Coghlan says.
"The discovery might also apply to cancer, because cancer cells often have abnormal numbers and arrangements of chromosomes," he adds. "Understanding one of the mechanisms by which cancers develop resistance to drugs could in turn open up new ways to combat cancer."
Unlike yeast cells, mammalian cells carry the p53 gene, which can disrupt the formation of abnormal cells. But p53 is often mutated in cancer, and mutated p53 wouldn't stand in the way of chromosomal reshuffling. The next step, the researchers tell Coghlan, is to determine whether the reshuffling is predictable, and whether it can be disrupted. Some new cancer drugs work by disabling Hsp90, so if this discovery holds true for cancer as well as yeast, it's possible these new drugs could eventually become ineffective as the cancer cells evolve resistance to them, he adds.