It is hoped that by preventing breast cancer from spreading through the metastasis of cancer cells, survival rates could be dramatically improved.
'Death rates from breast cancer remain high and relatively unchanged despite advances in medicine and technology. We wanted to find a way to stop metastasis from happening altogether. It is the turning point, where survival rates drop exponentially,' said Dr Noam Shomron of the Sackler School of Medicine, Tel Aviv, who carried out the study jointly with researchers at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts.
MicroRNAs are short strands of RNA that regulate gene expression, acting as master switches that control the activity of genes. The researchers had already identified two microRNAs – miR-96 and miR-182 – which control the expression of the protein palladin, which appears to promote breast cancer metastasis.
To deliver the treatment to the tumour cells, they embedded the nanoparticles containing the microRNAs into a hydrogel scaffold, and implanted this into the mouse tumours. This resulted in a dramatic reduction in breast cancer metastasis: 'We have stopped the spread of breast cancer in mice – zero metastatic sites in the lungs, liver and brain, and in every other organ we tested,' said Dr Shomron in a video.
The research was published in the journal Nature Communications and was carried out on mice with triple negative breast cancer – the most aggressive subtype. When the researchers added the chemotherapy drug cisplatin to the implant, the treatment was even more effective, reducing the size of the primary tumour as well as preventing its metastasis.
'We believe local delivery is much more effective [than systemic treatment] because it gives us a much higher effective dose of the cargo – in this case the two microRNAs and the cisplatin,' said Dr Natalie Artzi of MIT, who led the research.
'We are very excited about the results so far, and the efficacy seems to be really good. So the next step will be to move on to larger models and then to clinical trials, although there is still a long way to go,' she added.