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Role of microRNAs and microRNA machinery in the pathogenesis of diffuse large B-cell lymphoma.

ABSTRACT: Deregulation of microRNA (miRNA) expression has been documented in diffuse large B-cell lymphoma (DLBCL). However, the impact of miRNAs and their machinery in DLBCL is not fully determined. Here, we assessed the role of miRNA expression and their processing genes in DLBCL development. Using microarray and RT-qPCR approaches, we quantified global miRNAs and core components of miRNA-processing genes expression in 75 DLBCLs (56 de novo and 19 transformed) and 10 lymph nodes (LN). Differential miRNA signatures were identified between DLBCLs and LNs, or between the de novo and transformed DLBCLs. We also identified subsets of miRNAs associated with germinal center B-cell phenotype, BCL6 and IRF4 expression, and clinical staging. In addition, we showed a significant over-expression of TARBP2 in de novo DLBCLs as compared with LNs, and decreased expression of DROSHA, DICER, TARBP2 and PACT in transformed as compared with de novo cases. Interestingly, cases with high TARBP2 and DROSHA expression had a poorer chemotherapy response. We further showed that TARBP2 can regulate miRNA-processing efficiency in DLBCLs, and its expression inhibition decreases cell growth and increases apoptosis in DLBCL cell lines. Our findings provide new insights for the understanding of miRNAs and its machinery in DLBCL.

SUBMITTER: Caramuta S

PROVIDER: S-EPMC3816210 | biostudies-other | 2013

REPOSITORIES: biostudies-other

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Role of microRNAs and microRNA machinery in the pathogenesis of diffuse large B-cell lymphoma.

Caramuta S S Lee L L Ozata D M DM Akçakaya P P Georgii-Hemming P P Xie H H Amini R-M RM Lawrie C H CH Enblad G G Larsson C C Berglund M M Lui W-O WO

Blood cancer journal 20131011

Deregulation of microRNA (miRNA) expression has been documented in diffuse large B-cell lymphoma (DLBCL). However, the impact of miRNAs and their machinery in DLBCL is not fully determined. Here, we assessed the role of miRNA expression and their processing genes in DLBCL development. Using microarray and RT-qPCR approaches, we quantified global miRNAs and core components of miRNA-processing genes expression in 75 DLBCLs (56 de novo and 19 transformed) and 10 lymph nodes (LN). Differential miRNA ...[more]

PMID: 24121164

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Project description:Diffuse large B-cell lymphoma (DLBCL) is the most common type of B-cell non-Hodgkin lymphoma in adults and the pathogenesis of DLBCL is multifactorial and complex. Understanding the molecular mechanisms involved in DLBCL is important to identify new therapeutic targets. The present study aimed to screen and identify differentially expressed microRNAs (miRNAs/miRs) between diffuse large B-cell lymphoma (DLBCL) and control [lymph node reactive hyperplasia (LRH)] groups, and to investigate whether miRNAs associated with DLBCL could serve as potential therapeutic targets. In total, 5 DLBCL experimental samples and 5 control samples were obtained from fresh patient tissues. Firstly, the fresh samples were analyzed using miRNA microarray to identify differentially expressed miRNAs. Next, three databases (TargetScan, microRNA.org and PITA) were used to predict by intersection the potential target genes of the 204 differential miRNAs identified, and a Venn diagram of the results was performed. Subsequently, the target genes of differential miRNAs were analyzed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis. Finally, to validate the miRNA microarray data, reverse transcription-quantitative PCR (RT-qPCR) was performed for 8 differentially expressed miRNAs (miR-193a-3p, miR-19a-3p, miR-19b-3p, miR-370-3p, miR-1275, miR-490-5p, miR-630 and miR-665) using DLBCL and LRH fresh samples. In total, 204 miRNAs exhibited differential expression, including 105 downregulated and 54 upregulated miRNAs. The cut-off criteria were set as P≤0.05 and fold-change ≥2. A total of 7,522 potential target genes for the 204 miRNAs were predicted. Potential target genes were enriched in the following pathways: 'Cancer', 'MAPK signaling pathway', 'regulation of actin cytoskeleton', 'focal adhesion', 'endocytosis', 'Wnt signaling pathway', 'axon guidance', 'calcium signaling pathway' and 'PI3K/AKT signaling pathway'. A total of 8 miRNAs were validated by RT-qPCR, and 4 miRNAs (miR-19b-3p, miR-193a-3p, miR-370-3p and miR-490-5p) exhibited low expression levels in DLBCL (P<0.05), while miR-630 was highly expressed in DLBCL (P<0.05). Overall, the present study screened 204 differentially expressed miRNAs and analyzed the expression levels of 8 differentially expressed miRNAs in DLBCL. These differentially expressed miRNAs may serve as therapeutic targets for improvement of therapeutic efficacy in DLBCL in the future.

Project description:BackgroundDiffuse large B cell lymphoma (DLBCL) contains heterogeneous subtypes with various molecular dysregulation at the gene, protein and microRNA levels. Compared with the GCB subtype, the non-germinal center B-like (non-GCB)/activated B cell-like (ABC) subtype exhibits frequent progression despite standard immunochemotherapy. We aimed to investigate the effects of miR-197 on the progression and chemosensitivity of DLBCL with respect to the GCB and non-GCB/ABC subtypes.MethodsTo screen distinctively expressed microRNAs, microRNA expression patterns were analyzed in 10 DLBCL cases by microarray chip assays. Using quantitative real-time polymerase chain reaction (qRT-PCR), associations between miR-197 expression levels and clinicopathologic variables were investigated in 51 DLBCL tissue samples. The effects of miR-197 on doxorubicin chemosensitivity were investigated using the OCI-Ly1 and SUDHL9 cell lines.ResultsMicroRNA expression profiling by hierarchical clustering revealed that miR-197 was one of the distinctively expressed microRNAs in DLBCL. Quantitative analysis using qRT-PCR revealed that miR-197 levels were not correlated with clinicopathologic variables, including the international prognostic index, but low miR-197 levels were significantly associated with lymphoma progression defined by refractoriness, relapse or death in the rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP)-treated subgroup (n = 43; p = 0.004). Among the three molecular groups, i.e., the GCB, non-GCB/miR-197low and non-GCB/miR-197high groups, progression was most frequently observed in the non-GCB/miR-197low group in the full cohort (p = 0.013) and the R-CHOP cohort (p = 0.008). In survival analysis, low miR-197 levels were independently predictive of shorter progression-free survival in the R-CHOP cohort (p = 0.031; HR = 27.9) and the non-GCB subgroup (p = 0.037; HR = 21.5) but not in the GCB subgroup. Using SUDHL9 (ABC type) and OCI-Ly1 (GCB type) cells, the effects of doxorubicin on reducing cell viability were enhanced by miR-197 transfection. In apoptosis assays, miR-197 transfection enhanced doxorubicin-induced apoptosis in SUDHL9 cells but not in OCI-Ly1 cells, suggesting a chemosensitizing effect of miR-197 in ABC DLBCL.ConclusionsThese results suggest the role of miR-197 as a biomarker with potential therapeutic implications.

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Role of microRNAs and microRNA machinery in the pathogenesis of diffuse large B-cell lymphoma.

Publications

Role of microRNAs and microRNA machinery in the pathogenesis of diffuse large B-cell lymphoma.

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