GSE14738
Identification of novel Epstein-Barr Virus miRNA genes from Nasopharyngeal Carcinomas
MicroRNAs (miRNAs) represent a conserved class of small non-coding RNAs that are found in all higher eukaryotes as well as some DNA viruses. MiRNAs are 20-25 nucleotides (nt) in length and have important regulatory functions in biological processes such as embryonic development, cell differentiation, hormone secretion or metabolism. Furthermore, miRNAs have been implicated in the pathology of various diseases including cancer. MiRNA expression profiles not only classify different types of cancer but also may even help to characterize distinct tumor stages, therefore constituting a valuable tool for prognosis. Here we report the miRNA profile of Epstein-Barr Virus (EBV)-positive nasopharyngeal carcinoma (NPC) tissue samples characterized by cloning and sequencing. We find that all EBV miRNAs from the BART region are expressed in NPC tissues whereas ebv-miRNAs from the BHRF1 region are not found. Moreover, we identify two novel EBV miRNA genes originating from the BART region that have not been found in other tissues or cell lines before. We also identify three new human miRNAs, which might be specific for nasopharyngeal tissues. We further show that a number of different cellular miRNAs are upor down-regulated in NPC tissues compared to control tissue including miR-15a and miR-16. We find that the tumor suppressor BRCA-1 is a target of miR-15a as well as miR-16 suggesting a miRNA role in NPC pathogenesis. Overall design: 2 pairs of NPC and control tissues from 2 patients (4 samples in total) were examined.