孤儿核受体NR0B1促进非小细胞肺癌细胞重编程和耐药性产生的分子机制研究

Lung cancer causes the largest number of cancer-related deaths worldwide. Tumour stem cells(TSC)possess the stem cell-properties of self-renewal and the capacity of genetic reprogramming, which provides the establishment of drug resistance, tumour recurrence and metastasis in cancer. TSC have been proved to be present in lung cancer, thus the studies on lung TSC are promising for the prevention and treatment of lung cancer. Nuclear receptor subfamily 0 group B member 1 (NR0B1) is regarded as a typical X-linked cancer/germline gene. Our previous studies indicated that NR0B1 was ectopically expressed in the poorly-differentiated adenocarcinoma cells of male lung cancers and the side population (SP), which mainly have the stem cell-properties, of human lung adenocarcinoma A549 cells. The over-expression of NR0B1 increased the SP cell number in A549 cells; and the expression of other pluripotency transcription factors:SOX2, OCT4 and NANOG was up-regulated when NR0B1 was activated following the epigenetic modification. Considering NR0B1 plays a critical role in embryonic development, we herein hypothesize that the ectopic expression of NR0B1 is important for maintaining TSC activities. To address this issue, we firstly plan to perform a large cohort study that investigates the relation between the NR0B1 ectopic activation and the differentiation degree and prognosis of non-small-cell lung cancer(NSCLC). Then, considering that NR0B1 acts as a negative co-regulator of many sex hormone receptors and plays a critical role in the steroid hormones biosynthesis and that the sex hormone and their receptors are involved in lung cancer process, we would explore the role of the sex hormone regulation network under the control of NR0B1 in the TSC activities in NSCLC patients. We also plan to construct a signal pathway including NR0B1, SOX2, OCT4, NANOG, and etc and clarify the molecular mechanism of this pathway in maintaining the self-renewal, cell reprogramming, drug resistance arising and metastasis of lung cancer. Our study would prove the potentiality of NR0B1 as a molecular marker of TSC in NSCLC, and provide the theoretical basis for exploiting anti-lung cancer drugs.

肺癌是全球首要的癌症死亡病因。肺癌组织中存在肿瘤干细胞，其遗传重塑是肺肿瘤细胞耐药性产生、肿瘤复发及转移的物质基础，因此肺癌干细胞研究对肺癌防治至关重要。项目前期研究显示一个维持细胞多能性的关键分子孤儿核受体NR0B1在男性低分化肺腺癌及具有干细胞特征的腺癌细胞中高水平表达,NR0B1促进干性细胞增多，提示NR0B1在肺癌细胞中的异位激活可能参与肿瘤细胞的重编程，是肿瘤细胞干性维持的关键分子。本项目拟从临床大样本调查其异位激活对非小细胞肺癌癌细胞分化程度及预后的影响入手，通过体内外实验研究NR0B1调控的性激素系统对肺肿瘤干细胞生命活动的影响，解析NR0B1及其相互作用蛋白在调控肺肿瘤干细胞的自我更新、重编程、癌细胞转移以及耐药性产生过程中的分子信号途径。通过本项目研究将确立NR0B1作为非小细胞肺癌干细胞的分子标志地位，为肺肿瘤药物研发的提供理论基础。

肺癌是全球首要的癌症死亡病因，肺癌细胞产生耐药性是导致晚期肺癌预后不良的主要表现。项目在前期研究显示孤儿核受体NR0B1在低分化的非小细胞肺癌（NSCLC）组织中异位表达，可能参与肺肿瘤细胞的干性维持的基础上，本研究进一步通过临床数据调查，发现NR0B1在KEAP1突变型的肺癌患者中表达显著升高，NR0B1高表达导致患者生存期缩短，与肺癌患者预后较差呈正相关。NR0B1异位表达增强了肺肿瘤细胞的ALDH1A1、CD44和CD166基因等一些干性分子的表达。NR0B1过表达没有显著影响肺癌细胞对EGFR靶点药物奥西替尼的敏感性。不过，NR0B1的表达增强了肺肿瘤细胞对常规化疗药物顺铂和铁死亡诱导剂RSL3的药物抗性。接着，我们通过转录组学和体内外实验，揭示了NR0B1通过结合NRF2和JUN基因启动子区，上调二者的表达水平，而NRF2和JUN又作用于细胞铁死亡关键分子NCOA4、SAT1和CBS基因的启动子区，上调CBS基因的表达，下调NCOA4和SAT1基因的表达，进而增强了肺肿瘤细胞对铁死亡诱导剂RSL3耐药性。该项目研究首次确立NR0B1在NSCLC中的异位表达与其不良预后呈正相关，初步建立了NR0B1增强肺肿瘤细胞铁死亡诱导剂耐药性的分子信号通路。