若干决定肺癌细胞干性的长非编码RNA的功能研究

Lung cancer, which diagnosis mostly occurs at late stages, is a group of distinct diseases with genetic and cellular heterogeneity, and has a poor prognosis. Although lung cancer at stage I or II is operable, recurrence rates remain high at 50%. In human cancers, accumulating evidence shows that cancer stem cells (CSC) contribute to tumor initiation, progression and relapse. However, no universal lung CSC marker has yet been discovered. Our previous study showed that some non-coding RNAs play important regulatory roles in metastasis and stemness of lung cancer, and act as a therapeutic agent against the metastatic lung cancer (Wu, 2014 Oncogene; Wu, 2016 Oncotarget). These data indicate that non-coding RNAs widely affect the biological processes in metastasis and cell stemness, acting at both the transcriptional and posttranscriptional levels. Long non-coding RNAs (lncRNAs), a large fraction of the non-coding RNAs, have gained increasing attention, for lncRNAs comprise a very heterogenous group of transcrips and express abundantly in the mammalian genome. Therefore, we plan to use reliable serial xenograft assay to identify lung cancer stem cells that responsible for generating malignant lung cancer, then use Ribo-zero RNA-seq to discover the lncRNAs which are specific to lung cancer stem cells and the mechanism of regulation for lncRNA in lung cancer stem cells. Furthermore, the NSCLC prognosis model will be constructed based on the data of lncRNAs expression in a large amount of clinical samples. The goals of our project are to develop a screening test for lung cancer stem cells that can predict which patients are at high risk for developing lung cancer in order to diagnose lung cancer at an early stage, and to potentially develop a new stem cell based therapy for preventing and treating lung cancer.

肺癌是高度异质性的恶性肿瘤，预后差；即使I和II期病人也有50%死于术后复发。肿瘤干细胞是导致肿瘤复发等多种不利临床症状的根本原因，而肺癌干细胞特征性分子标记物的识别及对临床预后的应用鲜有报道。我们最近研究发现非编码RNA会同时调控癌症转移和肿瘤细胞干性；抑制肿瘤细胞干性可以有助于治疗转移性肺癌（Wu 2014;2016）。这表明肿瘤转移和干性广泛受着非编码RNA的表观调控，而lncRNA又是近几年新发现的种类最为丰富的非编码RNA。为此，本项目将基于裸鼠皮下肿瘤连续移植和肿瘤细胞原代培养，诱导分离肺癌干细胞，并利用全转录组测序发掘决定肺癌细胞干性演变的lncRNA；此外，从分子、细胞及动物模型等水平对这些lncRNA进行细致的功能分析，并整合大量临床样本的生物信息建立NSCLC 预后的统计学模型。本项目的顺利实施必将为肺癌干细胞的研究积累科学知识，为NSCLC的个性化治疗提供分子依据。

肺癌的发病率及死亡率位居世界首位。由于肺癌起病隐匿，目前仍然缺乏有效的筛查和早期诊断方法。而且很多病人在接受根治性手术后，仍会复发和转移。肿瘤干细胞是导致肿瘤复发、转移等多种不利临床症状的根本原因，单凭临床病理分期不能对预后做出准确评估。人类基因组中98%的转录RNA为非编码RNA，包括长链非编码RNA（lncRNA）和小RNA（miRNA），其中lncRNA是近几年新发现的种类最为丰富的非编码RNA，参与癌症转移和肿瘤细胞干性等多种细胞信号途经的调控。因此，本项目从lncRNA和miRNA两个层面展开研究：获得了具有明显干性特征的肺癌细胞，并鉴定出与肺癌细胞干性密切相关的非编码RNA，通过分子、细胞及动物模型等实验手段确定RP11-524D16_A.3和miR-708-5p与肺癌细胞干性有关，其表达量与肺癌患者的生存期存在显著正相关性，因此本项目所研究的RP11-524D16_A.3和miR-708-5p将在肺癌生存期预后中有一定的应用价值，为肺癌精准医疗提供依据。同时首次证实了miR-708-5p可以作为区分肺腺癌和肺鳞癌这两大主要病理学亚型的分子标记物，这在肺癌分型中有重要的实践应用价值。