c-Myc调控lncRNA NEAT1及亚核体paraspeckles参与CML细胞抗凋亡作用及其机制研究

Chronic myeloid leukemia (CML) is a clonal disease characterized by the presence of a constitutively active tyrosine kinase BCR-ABL oncoprotein. Although BCR-ABL is crucially important for pathogenesis and responsiveness to imatinib treatment, it is thought that some additional factors might involve in regulation of this process. We found that nuclear enriched abundant transcript1 (NEAT1), an lncRNA essential for the formation of nuclear body paraspeckles, is significantly repressed in in CML patients samples compared with those of healthy donors. We found that NEAT1 expression was repressed by BCR-ABL, and the expression of NEAT1 could be restored after treatment with imatinib. Importantly, NEAT1 was shown to be regulated by c-Myc in K562 cells, suggesting that NEAT1 and paraspeckles may play an important role in BCR-ABL-mediated CML. Here, we will explore the molecular mechanism of BCR-ABL/c-Myc-mediated regulation of NEAT1. Further,we will investigated the effect of NEAT1 and paraspeckles in imatinib-induced apoptosis of CML cells. Understanding the mechanisms of NEAT1 regulation and its roles in CML cells apoptosis may lead to a fuller understanding of the molecular events leading to CML, and provide novel potential targets for CML diagnosis and therapy.

基于慢性粒细胞白血病（CML）致病驱动分子BCR-ABL融合蛋白的靶向治疗（伊马替尼，IM）使CML的疗效显著改善，但仍存在对IM耐药及复发，除了与ABL基因突变之外，尚有许多未明确分子机制。我们研究发现，亚核体paraspeckles的结构支架长链非编码RNA（lncRNA） NEAT1的表达受到c-Myc调控并与抗IM诱导的细胞凋亡密切相关，提示BCR-ABL可能通过c-Myc调控NEAT1及paraspeckles在细胞凋亡中的作用。本课题拟研究①BCR-ABL对NEAT1表达及paraspeckles的影响；②c-Myc抑制NEAT1表达的机制；③NEAT1调控的paraspeckles在CML细胞凋亡中的功能机制。本研究将进一步明确BCR-ABL的新的分子作用机制；阐明NEAT1的表达调控及作用机制，探讨其在抗IM诱导的细胞凋亡中的作用，为改进CML的治疗提供新的思路和实验线索。

基于慢性粒细胞白血病（CML）致病驱动分子BCR-ABL融合蛋白的靶向治疗（伊马替尼，IM）使CML的疗效显著改善，但仍存在对IM耐药及复发，除了与ABL基因突变之外，尚有许多未明确分子机制。最近发现长链非编码RNA (lncRNA)的异常表达与包括癌症在内的多种疾病密切相关，提示lncRNA 极大可能也参与BCR-ABL介导的致癌过程。在此项研究中，我们发现lncRNA NEAT1是一种亚核体paraspeckle结构形成所必需的lncRNA，它在原代CML细胞中的表达受到显著抑制；抑制BCR-ABL表达或其激酶活性可恢复NEAT1表达；我们还证明了NEAT1受BCR-ABL下游信号通路及c-Myc调控；敲低NEAT1可以促进IM诱导的细胞凋亡，我们证明亚核体paraspeckle结构蛋白SFPQ是NEAT1介导的K562 细胞凋亡所必需的；RNA-seq分析显示SFPQ调控细胞增殖和死亡通路相关基因表达，与其在IM诱导的细胞凋亡中的功能相一致。本研究进一步明确了BCR-ABL的新的分子作用机制；阐明NEAT1的表达调控及作用机制，探讨其在抗IM诱导的细胞凋亡中的作用，为改进CML的治疗提供新的思路和实验线索。