New Data Reveal Protein Upregulation Activity for MicroRNAs in Cancer

A new study appearing in ACS Central Science finds that microRNAs can increase the expression of proteins in cancer cells, rather than only acting as down-regulators as previously believed. The role of miRNAs as suppressors of protein expression via gene silencing is well established, and many studies have linked dysregulation of the small, non-coding RNAs to cancer. However, miRNA activity in dividing cells — including proliferating cancer cells — is thought to be limited to the down-regulation of protein expression. Using a recently developed high-throughput fluorescence assay called miRFluR, University of Alberta scientists show that many miRNAs actually increase the expression of the glycosylation enzymes ST6GAL1 and ST6GAL2 in a variety of cancer cells. "Our results upend common assumptions surrounding miRNA, arguing that upregulation by these noncoding RNA is common," the investigators write. "Indeed, for some proteins, upregulation may be the dominant function of miRNA." The findings points to new possibilities for miRNAs mechanisms to modulate protein expression and highlights the need for new tools to more fully examine the biological roles of miRNAs, they add.