MiR-378a-3p is critical for Burkitt lymphoma cell growth

To gain further knowledge on the role of microRNAs (miRNAs) in the pathogenesis of Burkitt lymphoma (BL), we performed small RNA sequencing in BL cell lines and normal germinal center B (GC-B) cells. This revealed 26 miRNAs with significantly different expression levels. Altered levels were validated by qRT-PCR for six of eight selected miRNAs. For five miRNAs, the differential expression pattern was confirmed in BL primary tissues compared to GC-B cells. Inhibition of miR-378a-3p reduced the growth of multiple BL cell lines. RNA immunoprecipitation of Argonaute 2 followed by microarray analysis (Ago2-RIP-Chip) upon inhibition and ectopic overexpression of miR-378a-3p revealed 63 and 20 putative miR-378a-3p targets, respectively. These included 28 genes with a putative miR-378a-3p binding site. Effective targeting by miR-378a-3p was confirmed by luciferase reporter assays for four out of eight selected genes: MNT, FOXP1, IRAK4, and lncRNA JPX, all of which have been implicated in proliferation and cancer. In summary, our study identified several differentially expressed miRNAs in BL. We identified miR-378a-3p as a miRNA with an oncogenic role in BL and revealed 4 novel miR-378a-3p target genes, i.e. MNT, FOXP1, IRAK4, and JPX. Identification of miRNA targets (mRNAs and lncRNAs) in Burkitt lymphoma cell lines