Genetic regulators help stop the spread of cancer

Researchers from the Scripps Research Institute in Florida have discovered a group of genetic regulators that work together to stop cancer spreading.  This cluster of seven microRNAs (miRNAs) was previously thought to have a minor regulatory role, but has now been found to reduce epithelial-to-mesenchymal transmission (EMT).  This process is implicated in cancer development, namely the spreading of tumours (metastasis) and the development of cancer stem cells that are resistant to drugs.

MicroRNAs are small fragments of RNA (pieces of genetic information similar to DNA).  They bind to messenger RNAs (mRNAs), which carry the information from the DNA on how to make proteins.  When the miRNA binds to the mRNA, this normally leads to reduced gene expression.  Dr Phinney and his team who carried out the research silenced a particular cluster of miRNAs and found that this caused tumours to grow and spread more quickly.  This is because the cluster normally suppresses a specific signalling network in human cancers that can affect cancers such as breast cancer.

One of the miRNAs in this cluster (MiR-544) seems to be especially effective, as it induces the action of a protein that stops the formation of new cells once DNA damage is detected.  According to Dr Phinney, “What’s interesting is that MiR-544 blocks cell growth in every tumor cell line we’ve put it into, so we’re looking at it as a potential therapeutic target.”  This could be the basis of new types of cancer treatment.

There are many other miRNAs in the same genetic region, so there may be more clusters with regulatory roles in stopping tumour proliferation.  This is a promising step towards new cancer treatments, using genetic techniques to stop it spreading from its primary site.