By tracking the expression and location of almost 1,000 proteins in living cells, researchers have found new clues to how some cancer cells resist the chemotherapy drug camptothecin.
Camptothecin targets a DNA-binding protein called TOP1. Ariel Cohen of the Weizmann Institute of Science in Rehovot, Israel, and his colleagues labelled proteins in human lung cancer cells with different fluorescent tags, and then tracked the proteins for two days after camptothecin treatment.
About one out of every 10,000 cells survived the treatment. The reason seems to lie in the behaviour of two of the labelled proteins, DDX5 and RFC1, levels of which increased in surviving cells but decreased in those that died.