DESCRIPTION (provided by applicant): Cystic Carcinoma (ACC) is one of the most common forms of salivary gland tumors and has a poor long-term prognosis. Therapy for ACC involves complicated head and neck surgery followed by local radiation treatments, which may cure the local disease but leaves patients disfigured and with significant morbidity. In addition, most patients eventually succumb from distant metastases, so finding improved treatment strategies for ACC patients is a necessity. ACC tumors are frequently characterized by a recurrent translocation t(6:9), which fuses the MYB (c-Myb) proto-oncogene on chromosome 6q to the NFIB gene on chromosome 9p, resulting in the expression of novel Myb-NFIB fusion oncoproteins. The c-Myb protein encodes a potentially oncogenic transcription factor that regulates differentiation and proliferation in hematopoietic, epithelial and neural cells, and the Myb-NFIB fusion proteins have intact N-terminal Myb DNA binding domains but altered C-terminal domains fused to NFIB. Previous studies in our laboratory showed that the C-terminal domains of c-Myb control its selection of target genes, so the Myb-NFIB fusion proteins are likely to regulate different sets of genes than normal c-Myb. We propose three specific aims to identify the Myb-NFIB target genes in ACC tumors and to determine how and why they are targeted by the Myb-NFIB fusion oncoprotein. We have assembled a team of investigators with expertise in Myb protein biology, genomics, next-generation sequencing technologies, biostatistics, bioinformatics and computational methods to insure the success of this project. The experiments we propose will provide fundamental information about the causes of ACC tumors and they will produce important epigenetic and gene expression data sets that will be highly informative and that will help guide the development of novel therapeutic strategies for this devastating disease.

PUBLIC HEALTH RELEVANCE: This project focuses on the activities of a mutated regulator of gene expression, Myb-NFIB that is often produced as a result of a chromosomal translocation in Adenoid Cystic Carcinomas, one of the most common and most devastating forms of salivary gland tumors. We will investigate the functions of the aberrant regulatory protein produced in these tumors to determine how it contributes to tumor formation and to plot new strategies for disrupting its functions as treatments for this disease.