肺癌干细胞分子调控及靶向抑制

Lung cancer is the number one cancer killer with the highest occurrence and mortality rates in China, and these numbers are still growing due to severe air pollution and smoking propensity. Although cancer stem cells (CSCs, or tumor initiating cells) are believed in general to be responsible for cancer initiation, therapeutic resistance and cancer relapse, the understanding of molecular regulation of lung CSCs is very limited. Therefore, we propose to study the regulation and targeting of lung CSCs with three specific aims. Aim 1 is to identify novel genes or pathways involved in the regulation of lung CSCs by comparing mRNAs and lncRNAs in CSC (CD166+lin-) vs non-CSC tumor cells (CD166-lin-). Aim 2 is to validate and functionally characterize the differentially expressed candidate genes. These candidate genes in cell lines and CD166+ primary sphere cells should be inactivated or overexpressed depending on increased or decreased expression in CD166+ lung CSCs and evaluated in functional assays, including in vitro sphere forming and replating assay, in vivo serial xenograft assay, and in vivo transgenic/knockout murine models. Aim 3 is to design or screen for specific inhibitors (e.g. monoclonal antibodies, peptides, small interfering RNAs or small molecules) against characterized regulatory genes. The efficacy of candidate inhibitors against the stemness of lung CSCs will be validated using the in vitro and in vivo models in Aim 1 & 2. In summary, this project will improve our understanding of lung CSCs and facilitate the development of targeting therapies against lung cancer.

癌症干细胞被认为是肿瘤起始形成、耐药和复发的主要原因。因此，我们申请本课题---研究肺癌干细胞的调控和靶向治疗，包括以下三个明确目标：1）通过比对肺癌干细胞（CD166+lin-）与非肺癌干细胞（CD166+lin-）的mRNAs和lncRNAs，从而寻找出与肺癌干细胞调节相关的新调控基因或信号通路。2）验证和阐明这些差异表达候选基因在肺癌干细胞中的功能。根据这些候选基因在CD166+肺癌干细胞中表达上调或下调情况，在已建立的肺癌细胞系和CD166+原代肿瘤球细胞中失活或过表达这些基因，并通过多种功能实验（包括体外肿瘤悬浮球形成和连续传代实验、体内连续移植实验和体内转基因或基因敲除小鼠模型）来评估这些候选基因的功能。3）设计和筛选针对已验证的调节基因的特异性抑制剂，通过体外和体内模型，确认对肺癌干细胞干性调节的抑制。这项研究将增强我们对肺癌干细胞的认识，促进肺癌干细胞靶向治疗方法的研发。

已经发现肿瘤干细胞导致肿瘤发生、转移、复发和耐药，然而它们的病理特征在非小细胞肺癌中不是很清楚。在这个项目中，我们发现了两个新的肺肿瘤干细胞（LCSC）标记物，CD49f和CD104，由此我们能够分离出一个很纯的肺肿瘤干细胞亚群，这个群体在各种NSCLC的亚型中都有，占1.4%。这群细胞具有自我更新的能力，能在体外形成肿瘤球，肺肿瘤，以及肿瘤传代。我们发现NOTCH1在这群细胞中有更高的表达，通过HES1调控LCSC自我更新。让人惊奇的是，NOTCH1也能诱导LCSC中铂类耐药。利用低浓度gamma-secretase抑制剂就能消除铂类耐药，增加肿瘤干细胞对铂类药物的敏感性。而10倍浓度的gamma-secretase抑制剂能够直接抑制自我更新。我们分离了肺肿瘤干细胞，建立了他们的病理特征，找到了解决铂类耐药的一个方法。