MYC易位阴性的经典伯基特淋巴瘤病例:一种涉及微小RNA失调的替代致病机制

MYC translocation-negative classical Burkitt lymphoma cases: an alternative pathogenetic mechanism involving miRNA deregulation.

作者信息

Leucci E, Cocco M, Onnis A, De Falco G, van Cleef P, Bellan C, van Rijk A, Nyagol J, Byakika B, Lazzi S, Tosi P, van Krieken H, Leoncini L

机构信息

Department of Human Pathology and Oncology, University of Siena, Italy.

出版信息

J Pathol. 2008 Dec;216(4):440-50. doi: 10.1002/path.2410.

Abstract

The molecular feature of Burkitt lymphoma (BL) is the translocation that places c-Myc under the control of immunoglobulin gene regulatory elements. However, there is accumulating evidence that some cases may lack an identifiable MYC translocation. In addition, during the EUROFISH project, aiming at the standardization of FISH procedures in lymphoma diagnosis, we found that five cases out of 35 classic endemic BLs were negative for MYC translocations by using a split-signal as well as a dual-fusion probe. Here we investigated the expression pattern of miRNAs predicted to target c-Myc, in BL cases, to clarify whether alternative pathogenetic mechanisms may be responsible for lymphomagenesis in cases lacking the MYC translocation. miRNAs are a class of small RNAs that are able to regulate gene expression at the post-transcriptional level. Several studies have reported their involvement in cancer and their association with fragile sites in the genome. They have also been shown to control cell growth, differentiation, and apoptosis, suggesting that these molecules could act as tumour suppressors or oncogenes. Our results demonstrated a modulation of specific miRNAs. In particular, down-regulation of hsa-let-7c was observed in BL cases, compared to normal controls. More interestingly, hsa-mir-34b was found to be down-regulated only in BL cases that were negative for MYC translocation, suggesting that this event might be responsible for c-Myc deregulation in such cases. This hypothesis was further confirmed by our in vitro experiments, which demonstrated that increasing doses of synthetic hsa-mir-34b were able to modulate c-Myc expression. These results indicate for the first time that hsa-mir-34b may influence c-Myc expression in Burkitt lymphoma as the more common aberrant control exercised by the immunoglobulin enhancer locus.

摘要

伯基特淋巴瘤(BL)的分子特征是c-Myc基因易位至免疫球蛋白基因调控元件的控制之下。然而,越来越多的证据表明,某些病例可能缺乏可识别的MYC易位。此外,在旨在实现淋巴瘤诊断中荧光原位杂交(FISH)程序标准化的欧洲FISH项目中,我们发现,在35例经典地方性BL病例中,有5例使用分裂信号以及双融合探针检测时MYC易位呈阴性。在此,我们研究了BL病例中预测靶向c-Myc的微小RNA(miRNA)的表达模式,以阐明在缺乏MYC易位的病例中,是否可能存在其他致病机制导致淋巴瘤发生。miRNA是一类能够在转录后水平调控基因表达的小RNA。多项研究报道了它们与癌症的关联以及与基因组中脆性位点的关系。它们还被证明可控制细胞生长、分化和凋亡,这表明这些分子可能作为肿瘤抑制因子或癌基因发挥作用。我们的结果表明特定miRNA存在调控变化。特别是,与正常对照相比,在BL病例中观察到hsa-let-7c下调。更有趣的是,仅在MYC易位阴性的BL病例中发现hsa-mir-34b下调,这表明该事件可能是此类病例中c-Myc失调的原因。我们的体外实验进一步证实了这一假设,实验表明增加合成hsa-mir-34b的剂量能够调控c-Myc的表达。这些结果首次表明,hsa-mir-34b可能影响伯基特淋巴瘤中c-Myc的表达,这是免疫球蛋白增强子位点更常见的异常调控方式。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索