MicroRNAs in nasopharyngeal carcinoma.

Jeff P Bruce,Fei-Fei Liu

doi:10.5732/cjc.014.10175

Abstract

MicroRNAs (miRNAs) provide insight into both the biology and clinical behavior of many human cancers, including nasopharyngeal carcinoma (NPC). The dysregulation of miRNAs in NPC results in a variety of tumor-promoting effects. Furthermore, several miRNAs are prognostic markers for NPC. In addition to cellular miRNAs, NPC samples also often contain miRNAs encoded by Epstein-Barr virus, and these miRNAs may impact NPC biology by targeting both cellular and viral genes. Given their numerous putative roles in NPC development and progression, a thorough understanding of the impact of miRNA dysregulation in NPC is expected to shed light on useful biomarkers and therapeutic targets for the clinical management of this disease. In this review, we describe the efforts to date to identify and characterize such miRNAs in the context of NPC.

Highlights

MicroRNAs provide insight into both the biology and clinical behavior of many human cancers, including nasopharyngeal carcinoma (NPC)
MicroRNAs have been shown to provide insight into both the biology and clinical behavior of numerous human cancers, including nasopharyngeal carcinoma (NPC). miRNAs are known to function as both tumor suppressor genes and oncogenes, and their dysregulation has been found to be related to disease prognosis and clinical outcome
The primiRNA is cleaved within the nucleus by the type III RNase Drosha, in association with DiGeorge syndrome critical region gene 8 (DGCR8), at the stem of the loop structure to release a ~70 nt precursor miRNA[6]

Summary

MicroRNAs in NPC

Incorporated into the miRNA-inducible silencing complex (miRISC)[6]. this process is not completely understood, the guide strand is almost always the strand with the 5’ terminus that is least thermodynamically stable[10]. Binding occurs with either perfect complementarity or, more often, imperfect complementarity[5] In these instances of imperfect complementarity, there is often a short, ~6–8 nt “seed” region, located near the 5’ end of the miRNA, which appears to be of paramount importance in terms of dictating binding to specific target mRNAs[1]. These seed regions are often conserved among species and form the basis for many of the current in silico target prediction algorithms[6,14,15,16]. Prognostic, predictive, and biological roles have been described for miRNAs in NPC, as discussed below

Human miRNA expression in NPC

Prognostic association Negative

Conclusions