长链非编码RNA HOTAIR参与调控t(8;21)+白血病细胞的分化及其机制研究

Abstract..Our previous studies have found that the expression of lncRNA HOTAIR was specific absence in human acute myeloid leukemia(AML) cells with the (8;21)(q22;q22) chromosomal translocation,which involves AML1 gene on chromosome 21 and the ETO gene on chromosome 8, generates an AML1/ETO fusion.We also performed bioinformatics predication.The results of predication have indicated that the promoter region of HOTAIR exist several conserved AML1 binding sites.Firstly,we indicated that the AML1-ETO fusion gene could inhibit HOTAIR expression via competing with the transcriptional activation of AML1 by luciferase reporter arrays.HOTAIR is one gene whose expression is highly negative correlated with the presence of the AML1-ETO fusion. Therefore, we propose that the AML1-ETO acts as a dominant negative inhibitor of AML1 and represses the expression of HOTAIR invoved in leukemia cells differentiation.Based on our preliminary findings and the fact that AML1-ETO could act as a transcriptional repressor for HOTAIR of AML1 target gene. We propose the project and play to perfrom it as follow: 1) molecular biology, cell culture and other related-technologies will be performed in our study, from cell line level, we will investigate the regulation mechanisms of HOTAIR and ectopic expression of HOTAIR in leukemia cells with the(8;21)(q22;q22) chromosomal translocation whether induces cells differentiation; 2)Gene arrays analysis will be adopted to explore the key molecules at the downstream of HOTAIR involved in leukemia cells differentiation and therefore to reveal the important role of HOTAIR pathway in leukemia; 3)Fluorescence in situ hybridization (FISH)and other related methods will be utilized to detec the expression of HOTAIR in leukemia samples of different types and stages to reveal the relevance between HOTAIR and leukemia tumor progression.

摘要.我们前期研究发现长链非编码RNA HOTAIR在t(8;21)+的急性髓系白血病中特异性的表达缺失，生物信息学显示HOTAIR启动子区存在有保守的AML1结合位点，前期实验初步证明AML1-ETO通过竞争抑制AML1活性调控HOTAIR的表达。鉴于此，我们提出在t(8;21)+白血病中AML1-ETO通过抑制HOTAIR的表达参与白血病细胞分化调控,基于前期发现，本项目将：1）运用分子生物学、细胞培养等相关技术，从细胞水平研究t(8;21)+白血病细胞中HOTAIR的表达调控机制及它的异位表达对白血病细胞分化的影响；2）运用基因芯片等技术挖掘HOTAIR参与白血病细胞分化的下游关键分子，从而揭示HOTAIR参与的分子信号调控途径在白血病发生的重要作用；3）采用细胞原位杂交等方法研究HOTAIR在不同的AML分型、分期病人标本中的表达情况，揭示它们之间的关联性以及与白血病进展的关系。

基于前期的研究中我们发现长链非编码HOTAIR在多种肿瘤中表达异常，提示HOTAIR可能参与多种肿瘤的发生发展过程，本项目中，我们通过从细胞、动物及临床组织标本等不同的层面研究了HOTAIR参与食管癌的发生发展，证实HOTAIR作为食管癌发生中的致癌基因，在食管癌细胞的侵袭和转移中具有重要的促进作用，并与病人的生存和预后存在相关性，本项目的完成为后续的食管癌的临床诊断和治疗提供的新的思路和途径。此外，我们还发现microRNA在肿瘤的治疗抵抗中具有重要作用，研究表明microRNA-23a的在微卫星不稳定的结直肠癌中过表达能够增加肿瘤细胞对5-FU的化疗抵抗，为肿瘤治疗抵抗提供了新的表观靶点；肿瘤细胞可以通过抗氧化应激作用产生放化疗抵抗，但机制未名，我们在宫颈癌细胞中发现肿瘤细胞可以通过表达血红蛋白α与β链参与对抗过氧化氢等诱导的肿瘤细胞内活性氧的产生，为深入揭示肿瘤细胞钝化放化疗反应的机制提供了新的认识。