Research led by Dr. Suresh Alahari, the Fred Brazda Professor of Biochemistry and Molecular Biology at LSU Health Sciences Center New Orleans and its Stanley S. Scott Cancer Center, details exactly how the Her2 cancer gene promotes the progression and spread of breast cancer cells. The inactivation of a tumor suppression gene called Nischarin is among the mechanisms identified. The findings provide a new therapeutic target to block the function of Her2. The research was published in Cancer Research, OnlineFirst on January 21, 2013.
About 30% of breast cancers are positive for the Her2 oncogene. Although this gene is implicated in breast cancer, the exact mechanism has been unknown. In this study, the researchers showed that the Her2 oncogene activates two short microRNAs, called miR-27b and miR-23b, which in turn regulate breast cancer progression and lung metastasis. The study also shows, for the first time, that these microRNAs inactivate the function of a tumor suppressor gene called Nischarin, that Dr. Alahari's lab discovered.
Analysis to determine which of a number of cancer-related genes could be potential targets for miR-23b/27b found that only one other gene and Nischarin were directly targeted, and these microRNAs repressed its function. Nischarin is a novel protein that regulates breast cancer cell migration and movement. In a previous study, Dr. Alahari found that breast tumor growth and metastasis were reduced in the samples where they manipulated the overproduction of Nischarin.