Scientists at one of the world’s top mesothelioma research centers, the Asbestos Diseases Research institute in Sydney, Australia, say that restoring the expression of certain micro RNAs in the cells of mesothelioma patients may offer a new way to fight the disease.
A microRNA is a small RNA molecule which is involved in the regulation of gene expression. According to a new report in the Annals of Oncology, the Australian scientists found reduced expression of the micro RNA-15 family (miR-15/16) in the cells of mice with mesothelioma. “When malignant pleural mesothelioma cell lines were compared with the normal mesothelial cell line MeT-5A, the downregulation of miR-15/16 was 2- to 10-fold,” they report. This finding is consistent with previous cancer research that has suggested a link between the expression of these tumor-suppressing RNAs and other types of cancer.
The next step was to determine whether restoring miR-15/16 inside cells could help the body to fight mesothelioma. To test this, researchers injected synthetic miR mimics packaged in “minicells” into the mesothelioma-bearing mice.
The results were encouraging. Not only did restoring miR-15/16 expression inhibit the growth of mesothelioma cells, but it also appeared to make them more sensitive to chemotherapy with pemetrexed and gemcitabine, two of the most popular first-line drugs for mesothelioma. According to the report, injections of the miR-15/16 mimics led to “consistent and dose-dependent inhibition of malignant pleural mesothelioma tumor growth”. The team concludes that this miRNA-targeting method may offer a new way to combat this aggressive cancer.
Mesothelioma, a rare cancer caused by exposure to asbestos, is a major problem in Australia, which has one of the highest rates of the disease in the world. Because the early stages of the disease usually occur years after exposure and produce very few symptoms, mesothelioma is often not diagnosed until it is in its advanced stages, making treatment even more challenging. Australia has banned the mining, use and importation of asbestos products, but continues to pay a heavy price – in the form of mesothelioma, asbestos and other diseases – for decades of asbestos use.
Reid, G, et al, “restoring expression of miR-16: a navel approach to therapy for malignant pleural mesothelioma”, October 22, 2013, Annals of Oncology, Epub ahead of print.