A group of miRNAs could serve as a marker for cancer staging, according to researchers. They also believe that these miRNAs may be able to convert some advanced tumors to more treatable stages
The researchers studied a standard panel of 60 established human tumor cell lines representing nine different cancers as well as several specimens of human primary ovarian cancer. They showed that every tumor cell line they tested that had the epithelial marker E-cadherin and not the mesenchymal marker Vimentin had high amounts of the miRNA miR-200. Every cell line with high Vimentin and no E-cadherin had no detectable miR-200.
The authors also found that miR-200 helped regulate epithelial to mesenchymal transition. They bind directly to noncoding regions in the RNA of ZEB1 and ZEB2, known blockers of E-cadherin transcription. Both ZEB proteins have previously been implicated in human malignancies; ZEB1 in aggressive colorectal and uterine cancers and ZEB2 in advanced stages of ovarian, gastric, and pancreatic tumors.
By inhibiting miR-200, scientists could induce EMT. By introducing miR-200, they managed to activate production of E-cadherin protein and reverse tumors from a more-invasive mesenchymal into a less-invasive epithelial form.
The researchers involved were from the University of Chicago and Dartmouth Medical School. The study is published in the April 1 issue of Genes & Development.