lncRNA-DLEU1作为miR-200b/429的ceRNA促进胃癌恶性行为的功能与机制研究

In recent years, along with the development of genomics research, the importance of long non-coding RNA (lncRNA) in tumor related regulation network become more and more prominent. In our previous study, we identified lncRNA - DLEU1 was upregulated in gastric cancer (GC) tissues compared with adjacent normal tissues, and high expression of DLEU1 was significantly associated with malignant phenotype such as tumor size, etc. Knocking-down of DLEU1 inhibits the GC cell proliferation and metastasis. Moreover, bioinformatics analysis results show that a there exists a variety of miRNA binding sites in the sequence areas of DLEU1, including miR-200b/429.We speculated that DLEU1 may function as endogenous competitive RNA (ceRNA) of microRNAs, regulated the target gene of miRNA, and then mediate the GC malignant processes. In this project, we will further defined the function of DLEU1 in GC by using in vivo and in vitro experiments; identify the combination of DLEU1 and miR-200b/429, clarify the potential "DLEU1-miR-200b/429-target genes" signaling in GC by using bioinformatics analysis, molecular biology techniques, and function experimental; and detect the expression level of all those molecules in clinical samples, to analyze their clinical value. This study can help to clarify the functions and mechanism of DLEU1 in the development of tumor, shed new light on the accurate treatment of gastric cancer.

随着基因组学研究的深入，近年来长非编码RNA（lncRNA）在肿瘤相关调控网络中的重要性逐渐凸显。课题组前期研究发现lncRNA-DLEU1在胃癌中高表达且与肿瘤大小等恶性表型显著相关，敲减DLEU1可抑制胃癌细胞增殖和转移。生物信息学分析结果表明DLEU1序列区域存在miR-200b/429等多种miRNAs的结合位点。我们推测DLEU1可能作为miRNA的内源竞争性RNA，介导miR-200b/429靶基因调控胃癌恶性进程。本项目中，我们将利用体内外功能实验进一步明确DLEU1在胃癌中的功能；利用生物信息学分析、分子生物学和功能学实验鉴定DLEU1与miR-200b/429的结合，阐明“DLEU1-miRNA-靶基因”在胃癌中的作用机制；在临床样本中检测相关分子表达分析其临床转化价值。本研究可丰富DLEU1在肿瘤恶性生物学行为中的功能及机制理论，为胃癌的精准治疗提供理论依据和新的方向。

胃癌相关分子调控机制是目前研究的热点和难点。项目计划对lncRNA-DLEU1-miR-200b/429-靶基因对胃癌生长转移的调控作用进行研究，但是在执行过程中，及时发现了原课题假说的局限性，并调整了研究内容。本课题主要探索了长链非编码RNA DLEU1和PVT1调控胃癌生长转移的作用及机制。项目主要完成了以下研究内容：①lncRNA-DLEU1对胃癌细胞生长转移的促进作用；②DLEU1在胃癌中可与miR-149-5p互补结合；③DLEU1和PVT1在胃癌中显著高表达，其表达水平是胃癌预后独立影响因素；④lncRNA-PVT1在胃癌中的差异表达是胃癌恶性进展的促进因素而非伴随现象；⑤PVT1可与FOXM1特异结合行驶其促癌功能，体内可能存在一个可促进胃癌恶性生物学行为的PVT1-FOXM1正反馈环路。我们的研究研究了DLEU1、PVT1和FOXM1等分子在胃癌中的功能和作用机制，提示这些分子可能研制成为新的胃癌治疗靶点，本课题拓展了对于胃癌恶性表型相关调控机制和lncRNA DLEU1、PVT1在胃癌中的作用及下游分子机制的认识；同时也为癌蛋白FOXM1在胃癌中调控机制提供了新的研究视角和基础实验依据｡本课题有助于寻找新的胃癌预后监测分子标志物和分子治疗靶标，具有良好的理论意义和临床转化价值｡