Micrornas In Nasopharyngeal Carcinoma Research

MicroRNAs (miRNAs) are a family of small non-coding RNA molecules of about 19-25nt nucleotides in length, which regulate protein expression by binding 3'-UTRs (3'untranslated regions) of target mRNA. MiRNAs have been identified in plants and animals, and are conserved in sequence between distantly related organisms. MiRNAs play important roles in diverse biological functions, including development, differentiation, proliferation and apoptosis.Nasopharyngeal carcinoma (NPC) is one of epithelial origin malignant tumors, most of them are poorly differentiated. The cancer cells will be metastasis in the lymph dens covering the whole body, and the death rate is very high. Until nowadays, the pathology of NPC still remains unclear. This study aims to screen the differently expressed miRNAs based on miRNA microarrays in NPC, then to estimate the mechanism of miRNA effects on NPC carcinogenesis mediated by miRNA-mRNA regulations.The total RNA of 8 NPC tissues and 4 normal nasopharyngeal tissues was isolated by Trizol and then hybridized through Illumina microRNA Expression Profiling Panels. Then the miRNA arrays were scanned using Illumina BeadStudio Software.The method of Significance Analysis of Microarrays (SAM, version 3.02) was performed involving two class unpaired comparison. The results of miRNA microarrays were verified by real time RT-PCR.41 miRNAs were detected as differentially expressed by the MicroRNA microarrays, in which 6 miRNAs (miR-135b, miR-18a, miR-106b et al) were up-regulated, while 35 miRNAs (miR-34b, miR-34c, miR-10b, let-7, miR-449, miR-497) were down-regulated in NPC tissue compared with the normal samples. Through cluster analysis, we found the differentially expressed miRNAs were correlated with the clinical stage of NPC patients.Furthermore, we predicted the possible target genes of these miRNAs using Targetscan Database (Release 4.1) and then identified their enriched pathways through GenMAPP analysis. Reflected by the targets, the results indicated that these differentially expressed miRNAs were highly correlated with crucial signal transduction pathways, such as EGFR-1 signaling pathway, MAPK signaling pathway et al. We also found the small GTPase mediated signaling pathway was most significantly interfered by miRNAs; meanwhile, the Wnt signaling pathway was coordinated with the previous findings in our group.Based on the above analysis, our findings will certainly shed lights on nasopharyngeal carcinoma research by providing novel functions of the identified miRNAs for further clinical diagnosis.