Targeting Musashi-2 (MSI2) regulation of VEGFR2/VEGF-A in lung cancer

本提案的目的是了解非小细胞肺癌转移过程中发生的变化， 非小细胞肺癌（NSCLC）促进侵袭性表型和耐药性。细胞系组的比较 来自KrasLA 1/+; P53 R172 H ΔG/+（KP）小鼠模型的非转移性与高转移性肿瘤， 模拟人NSCLC，确定Musashi-2（MSI 2）的上调是NSCLC最一致的特征之一。 转移细胞通过分析两组独立的原始人体组织标本，我们确定 MSI 2表达在肿瘤进展过程中显著升高。使用六个独立的转移性 在小鼠和人NSCLC细胞系模型中，我们证明了MSI 2对于NSCLC侵袭是必需的， 体外和体内转移。候选通路分析和反相蛋白质阵列（RPPA）筛选 鉴定的EMT相关蛋白包括TGF-β I型受体（TGFBRI）、SMAD 3、claudins和 NSCLC中受MSI 2强烈调节的血管内皮生长因子受体（VEGFR 2）。我们直接 证明了这些蛋白质中的几种在MSI 2诱导侵袭中的功能作用。这项建议 重点是MSI 2对VEGFR 2及其配体VEGF-A的调节，因为已经确定了VEGFR的重要性 NSCLC中的信号传导，以及靶向该途径的药物的临床意义。 我们假设VEGFR 2和VEGF-A的自分泌MSI 2调节对于NSCLC侵袭是重要的， 信号传导和血管生成，这些蛋白质的旁分泌MSI 2调节支持肿瘤血管生成。在 在这项提议中，我们将通过临床前研究补充MSI 2调节VEGF信号传导的研究 强调靶向MSI 2和VEGF信号通路以改善治疗的重要性 NSCLC的策略。在目标1中，我们将使用体外实验来定义自分泌和旁分泌， MSI 2调节VEGF下游信号传导的结果。我们将测试MSI 2是否调节VEGFR 2- 非小细胞肺癌细胞在缺氧条件下的依赖性信号传导和生长以及MSI 2肿瘤表达是否影响 共培养实验中的内皮细胞生长，MSI 2调节靶mRNA的机制， 评价相关候选信号传导中间体。在目标2中，我们将确定MSI 2-VEGF在 使用原位异种移植模型和MSI 2-KP中的肿瘤生长、血管化和侵袭信号传导 转基因小鼠和人类组织微阵列中。在目标3中，我们将评估MSI 2作为响应的调节器， VEGFR 2/VEGF-A抑制剂（特别是卡博替尼和贝伐单抗与卡铂的组合）和 作为药物靶点。为了确定MSI 2是否是一个有用的药物靶标，我们将测试新的特异性靶点。 靶向MSI 2的化合物用于控制NSCLC。

The goal of this proposal is to understand how changes occurring during metastasis of non-small cell lung cancers (NSCLC) promote aggressive phenotypes and drug resistance. Comparison of cell line panels derived from non-metastatic versus highly metastatic tumors of the KrasLA1/+; P53R172HΔG/+ (KP) mouse model, which simulates human NSCLC, identified upregulation of Musashi-2 (MSI2) as one of the most consistent features of metastatic cells. From analysis of two independent sets of primary human tissue specimens, we determined that MSI2 expression is significantly elevated during tumor progression. Using six independent metastatic murine and human NSCLC cell line models, we demonstrated that MSI2 is essential for NSCLC invasion and metastasis in vitro and in vivo. Candidate pathway analysis and reverse-phase protein array (RPPA) screening identified EMT-associated proteins including the TGF-β type I receptor (TGFBRI), SMAD3, claudins, and the vascular endothelial growth factor receptor (VEGFR2) as strongly regulated by MSI2 in NSCLC. We directly demonstrated a functional role for several of these proteins in MSI2-induction of invasion. This proposal focuses on MSI2 regulation of VEGFR2 and its ligand, VEGF-A, given the established importance of VEGFR signaling in NSCLC, and the clinical interest of drugs targeting this pathway. We hypothesize that autocrine MSI2 regulation of VEGFR2 and VEGF-A is important for NSCLC invasion, signaling and angiogenesis, and paracrine MSI2 regulation of these proteins supports tumor angiogenesis. In this proposal, we will complement investigations of MSI2 regulation of VEGF signaling with preclinical studies addressing the importance of targeting MSI2 and VEGF signaling pathways to yield improved treatment strategies for NSCLC. In Aim 1, we will use in vitro experiments to define the autocrine and paracrine consequences of MSI2 regulation of VEGF downstream signaling. We will test if MSI2 regulates VEGFR2- dependent signaling and growth of NSCLC cells in hypoxia and whether MSI2 tumor expression affects endothelial cells growth in co-culture experiments, mechanism of MSI2 regulation of target mRNAs and evaluate relevant candidate signaling intermediates. In Aim 2, we will establish the role of MSI2-VEGF signaling in tumor growth, vascularization and invasion using both orthotopic xenograft models and in MSI2-KP transgenic mice and in human tissue microarrays. In Aim 3, we will evaluate MSI2 as a regulator of response to VEGFR2/VEGF-A inhibitors (specifically cabozantinib, and bevacizumab in combination with carboplatin) and as a drug target. In order to determine whether MSI2 is a useful drug target, we will test novel specific compounds targeting MSI2 for control of NSCLC.