血清分泌型lncRNAs作为胃癌无创性诊断标志物的价值研究

The early diagnosis of gastric cancer is difficult, which is one of the leading causes of high mortality. It is urgent to find new strategies to improve the early diagnostic rate. Long non-coding RNAs (lncRNAs) are a kind of RNA that is involved in the regulation of gene expression. It is recently reported that there is abundant stable lncRNAs in serum exosomes (secreting lncRNAs), and its aberrant expression are closely related to the tumorigenesis and progression of several types of tumors, suggesting that secreting lncRNAs are a kind of potential non-invasive biomarkers. However, the association between lncRNAs and gastric cancer has not been fully elucidated, and the diagnostic value of secreting lncRNAs in gastric cancer is still unknown. We previously got 32 differentially-expressed lncRNAs from the serum exosomes of healthy control, patient with atypical hyperplasia or gastric cancer via lncRNAs chip analysis. In this study, we will validate the 32-lncRNAs profile in a large cohort via high-throughput droplet digital PCR and support vector machines (SVM), screen lncRNAs that show the potential clinical value, and establish the specific diagnostic model for gastric cancer. The animal model of gastric cancer will be employed to further elucidate the early diagnostic value of the specific secreting lncRNAs. Finally, the in vitro assays will be used to demonstrate the effect of differentially-expressed lncRNAs on the biology of gastric cancer cell such as proliferation and apoptosis. This study is hopeful to provide novel approach for early screening of gastric cancer, and improve the prognosis of patients with gastric cancer.

早期诊断困难是导致胃癌高死亡率的重要原因之一，也是临床亟待解决的难题。长链非编码RNA（lncRNA）是一类参与基因表达调控的RNA分子。近期研究发现，血清exosomes存在丰富而稳定的lncRNAs（分泌型lncRNAs），其异常表达与肿瘤发生发展密切相关，具备成为无创标志物的潜能，然其在胃癌诊断中的价值尚未明确。课题组前期利用lncRNAs芯片测序技术从胃癌、不典型增生、健康对照血清exosomes中筛选出32个差异lncRNAs，现拟运用微滴式数字PCR高通量检测和支持向量机相结合的手段，通过大样本量分析，筛选有临床价值的lncRNAs并构建诊断模型；再利用胃癌动物模型体内研究分泌型lncRNAs的早期诊断价值；最后通过体外实验探讨差异lncRNAs对胃癌细胞增殖、凋亡等生物学行为的影响。本研究不仅为胃癌的早期筛查提供新途径，也为利用lncRNAs改善胃癌的诊疗效果提供实验依据。

早期诊断困难是导致胃癌高死亡率的重要原因之一，也是临床亟待解决的难题。长链非编码RNA（lncRNA）是一类参与基因表达调控的RNA分子。近期研究发现，血清外泌体（exosomes）存在丰富而稳定的lncRNAs，其异常表达与肿瘤发生发展密切相关，具备成为无创标志物的潜能。本课题分离鉴定了血清exosomes，然后对外泌体RNA进行全转录组（lncRNA、circRNA、mRNA）高通量二代测序。lncRNAs经过生物信息学、小样本、大样本验证后，筛选出胃癌相关血清exosomes lncRNAs，发现其在胃癌中的表达高于不典型增生、胃炎及健康对照，对胃癌具有较好的早期诊断价值，且与分期、转移等密切相关，是潜在的诊断标志物。利用MNNG成功诱导Wistar大鼠胃炎、不典型增生、上皮内瘤变动物模型，检测了不同节点血清exosomes lncRNAs表达。进一步体外细胞实验发现外泌体lncRNAs在胃癌增殖、侵袭过程中具有重要作用，同时对机制进行了初步研究。依托所建立的标本库，我们还对exosomes mRNAs进行了检测，发现其对胃癌具有较好的诊断价值，且是淋巴结转移的独立风险因子。本课题成果不仅为胃癌的早期筛查提供新途径，也为利用lncRNAs改善胃癌的诊疗效果提供实验依据。