MicroRNA regulation in mantle cell lymphoma

Abstract

8056 Mantle Cell Lymphoma (MCL) represents only 5–10% of all non-Hodgkins lymphomas, making it an uncommon but difficult form of lymphoma to treat. It has the worst prognosis among the B cell lymphomas with median survival of three years. The genetic hallmark of MCL is a t(11;14) q32 translocation which results in ectopic and dysregulated expression of cyclin D1. Recent comparative genomic hybridization studies have identied Syk as another gene important in the pathogenesis of MCL. Previous studies have suggested that post transcriptional regulation of Cyclin D1 and Syk may be important the pathogenesis of in MCL. MicroRNAs are a new class of abundant small RNAs that play important regulatory roles at the post transcriptional level by binding to the 3’ untranslated region (UTR) of mRNAs blocking either their translation or initiating their degradation. There have been numerous reports of misregulation of microRNAs and their targets in human cancers. We hypothesized that altered microRNA regulation of cyclin D1 and/or Syk may be present in MCL. Based on bioinformatics, we identified 8 microRNAs and their putative docking sites in either Cyclin D1 and Syk. We then examined their integrity in MCL cell lines, and identified a mutation in the 3’UTR of Syk at the docking site of 1 mir-452* and a SNP in mir-458. Using a GFP reporter construct with the mutated Syk 3’UTR we demonstrated that this mutation resulted in altered microRNA function. We also show that mimics of the microRNA leads to down regulation of Syk protein. This data suggests that microRNA regulation of important genes in MCL may be compromised and play a role in the development and progression of this disease. No significant financial relationships to disclose.