The long term goal of this research has been to determine the role of EBV in the etiology of nasopharyngeal carcinoma (NPC), an epithelial malignancy that develops with high incidence in Southern China, Northern Africa, and among Alaskan Inuits. We have previously identified the viral genes that are expressed in NPC and assessed the molecular properties of these proteins on cellular signaling and growth regulation. Our studies have shown that latent membrane protein 1 (LMP1) is expressed in NPC and has potent effects on cellular transcription, multiple cell signaling pathways, cell growth regulation, and biologic properties. This application is based on the hypothesis that specific genes are induced by the distinct transcriptional complexes induced by LMP1 and that the pleiotropic effects of LMP1 on signaling are mediated by unique complexes that form within plasma membrane domains and cytoplasmic vesicles. We suggest that LMP1 modulates the constituents of lipid raft domains to form exosomes that affect the growth of neighboring cells via a paracrine mechanism.
Our specific aims are: 1.) Identify the epithelial cellular targets that are regulated by LMP1-CTAR1 through the p50/p50-Bcl-3 transcriptional complex and activated STAT3 using chromatin immunoprecipitation (ChIP) analysis and ChIP-seq technology. 2.) Determine the composition of signaling complexes induced by LMP1 and mutants of LMP1 that have distinct functional properties using immunofluorescence, cell fractionation, immunoprecipitation, 2-D fluorescent differential gel electrophoresis, and mass spectrometry. 3.) Characterize exosomes that are produced by cells expressing LMP1. Identify their composition using immunoselection and mass spectrometry, and assess the biologic effects in cells exposed to the induced exosomes.
Epstein Barr virus is considered a cause of multiple cancers and is consistently detected in nasopharyngeal carcinoma (NPC), a malignancy of epithelial cells that occurs at very high incidence in some populations. We have shown that the viral proteins of EBV can change the growth regulation of cells in culture and in mouse models through major effects on cellular gene expression and growth control and that these same changes occur in NPC. This grant will continue to study latent membrane protein 1 (LMP1), a viral gene that regulates cellular expression through the effects on transcription factor complexes and activates multiple cellular signaling pathways to activate cell growth. This application will identify the individual genes that are regulated by specific transcription complexes and determine the mechanisms through which LMP1 activates distinct signaling pathways.
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