一个胃癌相关新lncRNA的生物学功能及其分子机制研究

From a worldwide perspective, gastric cancer is one of the most malignant cancer. Despite multiple efforts have been made to explore the mechanism of gastric cancer development and progression, gastric cancer is still a main clinical burden nowadays. Accumulated evidence indicates that long noncoding RNA plays an important role in the regulation of gene transcription, and its mutation and abnormal expression have a close relationship with the occurrence of diseases, especially in tumorigenesis and cancer progression. However, the function and mechanism of long noncoding RNA in gastric cancer development and progression hasn't yet been reported. We detected the expression profile of long noncoding RNA and mRNA in gastric cancer samples compared with their adjacent normal gastric tissues through the Arraystar human lncRNA Array . Our microarray data shows that a series of lncRNA, such as lncRNA LIT, was deregulated in gastric cancer. Quantitative real-time PCR detected that lncRNA LIT was significantly upregulated in gastric cancer. We further found that changing lncRNA LIT expression in gastric cancer cell lines can greatly modulate cell migration ability. This project aims to screen and identify gastric related lncRNA LIT through kinds of modern technology of bioinformatics, molecular cytobiology, biochemistry and imaging, with studying the function and molecular mechanism of the selected lncRNA LIT in gastric cancer cell migration, invasion and tumor formation. The implementation of this project will be helpful for understanding the molecular mechanism of gastric cancer development and progression, and providing new theoretical proofs for selecting new diagnostic biomarkers and potential therapy targets in gastric cancer.

胃癌是严重危害我国人民生命健康的重大疾病，然而其发病机理至今尚未明确。最近研究表明，长链非编码RNA（lncRNA）在基因转录调控过程中发挥着重要作用，其异常与多种疾病（包括肿瘤）的发生发展密切相关；但是，目前尚无系统研究功能未知lncRNA在胃癌发生发展中作用的报道。我们应用生物芯片技术，同时筛选在胃癌组织中差异表达的lncRNA和mRNA，发现了多个胃癌相关lncRNA，其中包括功能未明的lncRNA LIT；进一步研究显示lncRNA LIT在胃癌组织中高表达，改变其表达水平可显著影响细胞迁移能力，但不影响细胞增殖水平。本课题在此基础上综合应用生物信息学、细胞分子生物学和现代成像等技术，深入研究lncRNA LIT在胃癌细胞迁移、侵袭、瘤体形成及转移等生物学过程中的功能及其分子作用机制。本课题的开展将有助于了解胃癌发生发展的分子机理，为胃癌的诊断治疗提供新的理论依据与潜在的分子靶点。

胃癌是消化系统常见的恶性肿瘤，本研究目标是系统研究长链非编码RNA在胃癌发生发展中的作用，阐明其对胃癌细胞生物学行为的影响及其分子机制，目前已较圆满完成预期目标。我们应用运用基因表达芯片技术，同时检测胃癌组织样本中的lncRNA和mRNA的表达谱；在临床胃癌肿瘤样本中验证包括lncRNA-MTM在内的数个lncRNA在组织中的表达情况及其与临床特征的相关性；挑选胃癌相关lncRNA-MTM，深入研究其在胃癌细胞生物学过程中的功能；研究胃癌相关lncRNA影响胃癌细胞生物学行为的分子机制。研究结果：我们发现lncRNA-ENO1、lncRNA-AK023、lncRNA-ABH在胃癌组织中相对上调，而lncRNA-MTM在胃癌组织中相对下调。LncRNA-MTM与胃癌TNM分期、肿瘤侵润深度、淋巴结转移及患者预后相关。过表达lncRNA-MTM抑制胃癌细胞迁移和侵袭、抑制细胞增殖、诱导细胞凋亡。根据芯片结果绘制lncRNA-mRNA互作网格图，筛选lncRNA-MTM的潜在互作基因。发现在胃癌细胞和组织中lncRNA-MTM与MT1F表达存在正相关。MT1F过表达抑制胃癌细胞的迁移和侵袭，敲低MT1F可以部分逆转MTM过表达细胞的迁移和侵袭能力，提示MT1F可能是lncRNA-MTM重要的靶基因。结论：lncRNA-MTM在胃癌中低表达，表现为抑癌作用，并可能通过调控MT1F的表达影响胃癌细胞的迁移、侵袭能力。