Progress toward targeted cancer therapies: A new role for microRNA

In 2001, the targeted drug imatinib (Gleevec) was hailed as one of the first “bullet” treatments for cancer: a targeted therapy that successfully disrupted a molecular pathway involved in tumor growth. Are there more targeted therapies on the horizon? Carlo Croce, one of the scientists whose work drives development of such drugs, is optimistic. Croce showed in 2002 that the molecular pathways to cancer all involve dysregulation of microRNAs—small noncoding RNA molecules now known to be important in the regulation of gene expression. Recently his lab found that when microRNAs are carried from a cancer cell by exosomes, the small vesicles that bud off the membrane of the cell, they can transmit a signal that promotes remote tumor development or can act directly as hormones to induce cell death. This has led to a new hypothesis about cachexia, the muscle wasting that makes late-stage lung and pancreatic cancers untreatable, and proposals for targeted therapy to prevent the death of muscle cells so these patients can be treated.

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