Tumor-Suppressive microRNAs


By Thalyana Smith-Vikos

MicroRNAs (miRNAs) are short, noncoding RNAs that inhibit the expression of specific target genes. Certain classes of miRNAs have been identified as tumor suppressors, most notably miR-34. Studies have shown that miR-34 can be delivered as a tumor-static agent, including a 2012 report by Kasinski and Slack in Cancer Research. This report identifies miR-34 as a tumor suppressor in a Kras;p53 mouse model of lung cancer, the most potent cause of cancer deaths around the world. Tumors harvested from these mice had elevated levels of miR-34 targets, including Met and Bcl-2, indicating that miR-34 expression was inhibited. By adding exogenous miR-34, both tumor formation and progression of preformed tumors were prevented in the mice, and proliferation and invasion of lung tumor-derived epithelial cells were inhibited. This and other studies show promise for the use of miRNAs, especially miR-34, in clinical trials for cancer treatment and prevention.