Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, Texas, United States of America.
PLoS One. 2011;6(11):e27271. doi: 10.1371/journal.pone.0027271. Epub 2011 Nov 10.
Nasal NK/T cell lymphomas (NKTCL) are a subset of aggressive Epstein-Barr virus (EBV)-associated non-Hodgkin's lymphomas. The role of EBV in pathogenesis of NKTCL is not clear. Intriguingly, EBV encodes more than 40 microRNAs (miRNA) that are differentially expressed and largely conserved in lymphocryptoviruses. While miRNAs play a critical role in the pathogenesis of cancer, especially lymphomas, the expression and function of EBV transcribed miRNAs in NKTCL are not known. To examine the role of EBV miRNAs in NKTCL, we used microarray profiling and qRT-PCR to identify and validate expression of viral miRNAs in SNK6 and SNT16 cells, which are two independently derived NKTCL cell lines that maintain the type II EBV latency program. All EBV BART miRNAs except BHRF-derived miRNAs were expressed and some of these miRNAs are expressed at higher levels than in nasopharyngeal carcinomas. Modulating the expression of BART9 with antisense RNAs consistently reduced SNK6 and SNT16 proliferation, while antisense RNAs to BARTs-7 and -17-5p affected proliferation only in SNK6 cells. Furthermore, the EBV LMP-1 oncoprotein and transcript levels were repressed when an inhibitor of BART9 miRNA was transfected into SNK6 cells, and overexpression of BART9 miRNA increased LMP-1 protein and mRNA expression. Our data indicate that BART9 is involved in NKTCL proliferation, and one of its mechanisms of action appears to be regulating LMP-1 levels. Our findings may have direct application for improving NKTCL diagnosis and for developing possible novel treatment approaches for this tumor, for which current chemotherapeutic drugs have limited effectiveness.
鼻型自然杀伤/T 细胞淋巴瘤（NKTCL）是一种侵袭性 Epstein-Barr 病毒（EBV）相关非霍奇金淋巴瘤。EBV 在 NKTCL 发病机制中的作用尚不清楚。有趣的是，EBV 编码了 40 多种差异表达且在淋巴隐病毒中广泛保守的 microRNAs（miRNA）。虽然 miRNA 在癌症的发病机制中，特别是在淋巴瘤中发挥着关键作用，但 EBV 转录的 miRNA 在 NKTCL 中的表达和功能尚不清楚。为了研究 EBV miRNA 在 NKTCL 中的作用，我们使用微阵列分析和 qRT-PCR 来鉴定和验证 SNK6 和 SNT16 细胞中病毒 miRNA 的表达，这两种细胞系是两种独立衍生的 NKTCL 细胞系，维持着 EBV Ⅱ型潜伏程序。除了 BHRF 衍生的 miRNA 外，所有 EBV BART miRNA 均有表达，其中一些 miRNA 的表达水平高于鼻咽癌。用反义 RNA 调节 BART9 的表达可一致降低 SNK6 和 SNT16 的增殖，而反义 RNA 对 BARTs-7 和 -17-5p 的影响仅在 SNK6 细胞中影响增殖。此外，当将 BART9 miRNA 的抑制剂转染到 SNK6 细胞中时，EBV LMP-1 癌蛋白和转录物水平受到抑制，而 BART9 miRNA 的过表达增加了 LMP-1 蛋白和 mRNA 的表达。我们的数据表明 BART9 参与了 NKTCL 的增殖，其作用机制之一似乎是调节 LMP-1 水平。我们的研究结果可能对改善 NKTCL 的诊断具有直接应用价值，并为这种肿瘤开发新的治疗方法提供可能，因为目前的化疗药物对这种肿瘤的疗效有限。
