Msi2 regulates the aggressiveness of Non-Small Cell Lung Cancer (NSCLC)

 描述(申请人提供)：使用KrasLA1/+；P53R172H∆G/+(KP)小鼠模型，模拟非小细胞肺癌，我们比较了来自非转移性肿瘤和高转移性肿瘤的细胞系。这确定了MSI2的上调是转移细胞最一致的特征之一，MSI2是一种调节mRNA翻译的RNA结合蛋白。在对123例原发人类非小细胞肺癌标本的初步探测中，已发现肿瘤组织中MSI2显著高于正常肺上皮，提示与患者的非小细胞肺癌有关。在四个独立的小鼠和人转移NSCLC细胞系中，MSI2基因敲除降低了体外侵袭力，初步证实减少了体内转移。候选通路分析和反相蛋白质阵列筛选鉴定出与子宫内膜转运蛋白相关的蛋白，包括转化生长因子-β受体I型(转化生长因子-βRI)、Notch抑制因子Numb、纤维连接蛋白(Fn1)和Claudin-7，它们都受MSI2的强烈调控。研究人员推测，MSI2对这些蛋白的调控对于其在侵袭和转移中的作用至关重要，并为转移性非小细胞肺癌中依赖Notch-和Tf-βRI的致癌信号提供了必要的支持。我们的目的是在体外探索这些机制，确定MSI2的表达是否调节针对Notch和转化生长因子-βRI的药物的反应，并确定我们已经确定的关系是否预测了人类肿瘤中的通路活性。目的1将验证MSI2依赖的信号效应器的功能意义，重点是NumB/Notch、转化生长因子-β和新靶点之间的相互连接，例如细胞连接调节蛋白Claudin-7。这项工作将强调MSI2的表达在γ分泌酶(Notch靶向)和βRI抑制剂的反应中的作用，并将信号和药物反应的体外分析与异种移植分析相结合。目的2探讨肿瘤组织中MsI2的表达与肿瘤组织中Notch、转化生长因子β、CLDN7、E-钙粘蛋白及临床资料的相关性。在补充实验中，研究人员将使用有条件的129S/Sv-Krastm3Tyj/J；Trp53tm1Brn/J；MSI2-/-小鼠模型来确定MSI2在肺肿瘤发生的不同阶段的作用，包括早期生长、侵袭和转移。

 DESCRIPTION (provided by applicant): Using the KrasLA1/+; P53R172H∆G/+ (KP) mouse model, which simulates NSCLC, we compared cell lines derived from non-metastatic versus highly metastatic tumors. This identified upregulation of Msi2, an RNA-binding protein that regulates mRNA translation, as one of the most consistent features of metastatic cells. In an initial probe of 123 primary human NSCLC specimens, it has been found that Msi2 is significantly elevated in tumors versus normal lung epithelium, suggesting relevance to NSCLC in patients. Msi2 knockdown in four independent murine and human metastatic NSCLC cell lines decreased invasion in vitro, with preliminary confirmation of reduced metastasis in vivo. Candidate pathway analysis and reverse-phase protein array (RPPA) screening identified EMT-associated proteins including the TGF-β receptor Type I (TGF-βRI), the Notch inhibitor Numb, fibronectin (FN1), and claudin-7, as strongly regulated by Msi2. The investigators hypothesize that Msi2 regulation of these proteins is critical for its role in invasion and metastasis, and provides essential support for Notch- and TGF-βRI dependent oncogenic signaling in a subset of metastatic NSCLC. The objective is to explore these mechanisms in vitro, determine whether Msi2 expression regulates the response to drugs targeting Notch and TGF-βRI, and determine whether the relationships we have identified predict pathway activity in human tumors. Aim 1 will validate functional significance of Msi2 dependent signaling effectors, focusing on interconnection between NUMB/Notch, TGF-β, and novel targets such as the cell junction regulator claudin-7. This work will emphasize the role of Msi2 expression on response to γ- secretase (Notch-targeting) and TGF-βRI inhibitors, and will combine in vitro analysis of signaling and drug response with xenograft analysis. Aim 2 will establish if expression of Msi2 expression correlates with Notch, TGF-β, CLDN7, and E-cadherin, and clinical data in cancer patients. In complementary experiments, the researchers will use a conditional 129S/Sv-Krastm3Tyj/J; Trp53tm1Brn/J; Msi2-/- mouse model to determine the action of Msi2 at discrete stages of lung tumorigenesis, including early growth, invasion, and metastasis.