BCM Logo MicroRNA has been recently identified as a crucial element in the battle against breast cancer. A team of investigators from the Baylor College of Medicine suggests that the microRNA-1258 blocks the enzyme heparanase which is a key towards the spread of breast tumors to the brain. This enzyme appearing as an important mediator of brain metastasis is regulated by microRNAs.

During the research, it was observed that the microRNA-1258 controls the post-transcriptional activity of the heparanase gene and also its activity in curbing the metastasis of breast cancer to the brain. Not more than 22 nucleotides in size, microRNAs probably bind to messenger RNA, which carries the genetic code for a protein to the cell’s organelles that make it. On binding to the messenger RNA, it seemingly halts the production of that protein. At the time of the investigation in laboratory, several forms of breast cancer cells in culture, laboratory animals and human tissues were used. As a result, microRNA-1258 supposedly targeted only the gene for heparanase and decreased production of the enzyme.

“Our investigations introduce new concepts that brain metastasis might be inhibited by microRNA-based strategies, and can have profound implications for the development and use of heparanase-based therapeutics in cancer metastasis in general and brain metastatic breast cancer in particular,” stated Dr. Dario Marchetti, lead investigator and professor of pathology and immunology, cell and molecular biology at BCM and member of the NCI-designated Dan L. Duncan Cancer Center at the College.

Scientists also registered remarkably reduced levels of microRNA-1258 in breast tumor cells that have high propensity for metastasis to the brain. Highest levels of heparanase were reportedly found in invasive ductal carcinoma, which is a type aggressive primary breast cancer, and in brain metastatic breast cancer. The microRNA-1258 possibly inhibited brain metastases by 74 percent when introduced into breast cancer cells injected into animals in the laboratory.

The research is published in the current issue of the American Association for Cancer Research journal Cancer Research.