研究经典wnt信号通路在肺癌谱系分化中的作用及机制

The canonical wnt signaling pathway plays a important role in the specification and morphogenesis of embryonic lung, but wheather this pattern is retrospectively presented in lung cancer is still largely unknown. We have previously proved that the de novo lung ADC with LKB1 deficiency can transdifferentiates to SCC, which provide us with a promising system to further characterize the plastic property of lung caner. Interestingly, our current data show that several key genes of canonical wnt signaling pathway dramatically downregulated in the SCC from KRAS/LKB1 mice. Based on this, we are going to investigate the regulational role of canonical wnt signaling pathway in lung cancer lineage commitment through integrative studies on mouse models, cell lines and human lung cancer specimens. With the bioinformatic analyses on the gene expression profile of ADC and SCC from both human and mouse, we seek to establish the biological correlation between canonical wnt signaling pathway and lung cancer lineage associated genes. Moreover, we will decipher the beta-catenin role in the modulation of lung cancer lineage commitment in mouse models. The conditional gain-of-function (beta-cateninDelE3) and lose-of-gunction (beta-cateninL/L) mutations of beta-catenin mouse as well as lung cancer lineage tracing mouse model will be introduced into KRAS/LKB1 mice to see if the dysregulation of wnt pathway could change the lung cancer lineage fate. The further in vitro and in vivo studies will be performed to reveal the mechanism of this regulationship based on the identification of lung cancer lineage genes by microarray analyses. Hopefully, we will transfer our findings from mouse model to clinical lung cancer samples to make a clinical relevance analyses. We plan to take advantage of the established lung ADC PDX (patien-derived exnograft, PDX) mouse models to perform serial transplantation with or without the interfere of essential signaling pathways identified from the present study and test if possible that human ADC with LKB1 inactivation can be well targeted by the combination therapy.

经典wnt信号通路在小鼠胚胎期肺脏的发生及细胞命运决定中发挥至关重要的作用，但该通路是否调节肺癌谱系分化仍不清楚。我们前期研究证实了LKB1缺失的小鼠肺腺癌可以向肺鳞癌发生转分化，为肺癌表型可塑性研究提供了重要的理论基础。目前我们初步研究数据表明经典wnt信号通路在KRAS/LKB1小鼠肺鳞癌中显著下调。基于此，我们将通过基因表达谱分析建立人和小鼠肺癌样本中wnt信号通路与肺癌谱系基因的生物学关联。然后分别构建beta-catenin激活型和失活型动物模型以及谱系追踪小鼠模型，从不同角度证实经典wnt信号通路在小鼠肺癌谱系决定中的作用，并进一步在体外和体内水平阐明他们之间的调控机制。最后我们将建立人肺癌小鼠体内嫁接模型，分别在KRAS/LKB1小鼠模型和肿瘤嫁接小鼠模型中进行针对肿瘤分化及胞外基质合成的联合靶向药物处理，以期克服耐药并达到治愈肿瘤的目的。

肺腺癌和肺鳞癌是非小细胞肺癌的两种重要亚型。通过多种动物模型的研究，我们首次在体内证实了肺腺癌可以向肺鳞癌发生转分化，并揭示这种肺癌亚型的转化会导致肿瘤发生明显的耐药，但转分化后的鳞癌得以生存并产生耐药的分子机制尚不清楚。本项目旨在研究转分化后肺鳞癌存活的分子机制，并利用各种动物模型进行研究从而克服转分化导致的耐药。通过蛋白质谱分析我们发现wnt信号通路在转分化后的肺鳞癌中显著激活，并且这种激活促进了肺鳞癌对氧化应激的适应。我们在KRAS/LKB1小鼠模型基础上分别引入了β-catenin激活和失活的小鼠模型，证明wnt通路失活抑制了鳞癌的存活，相反早期wnt通路激活清除了肿瘤积累的氧化应激从而抑制了转分化，而通过wnt通路激活剂LiCl处理晚期肺癌小鼠发现可以显著促进后期鳞癌的生长。进一步我们构建了LKB1缺失人肺癌样本小鼠嫁接模型，分别进行氧化应激诱导药物Phenformin和wnt通路小分子抑制剂处理，发现抑制wnt通路显著促进小鼠肿瘤对phenformin的响应并克服了由于转分化导致的耐药。本项目系统的利用了蛋白组学分析、动物模型实验以及体外分子机制研究等研究手段，揭示了转分化后肺鳞癌耐药的分子基础，为临床上针对LKB1缺失肺癌病人的个体化治疗提供了理论基础。