Novel arginine-methylation mediated regulation of YAP1 in K-Ras mutant lung adenocarcinomas

肺癌是美国癌症相关死亡的主要原因，占大多数，约85%。 非小细胞肺癌（NSCLC）NSCLC的总体生存率较低，原因是 对靶向治疗的反应和耐药性的发展。虽然免疫疗法对大约 然而，30%的KRAS癌基因突变患者并不能使绝大多数患者受益。 病人在这种情况下，研究表明，转录辅激活蛋白YAP 1，一个下游转录因子， Hippo信号通路的介导物，在肿瘤的干细胞、生长和转移中起主要作用。 非小细胞肺癌在目前的研究中，我们发现一种非经典的I型酪氨酸激酶TBK 1（Tank-binding Kinase 1）， 物理相互作用并磷酸化YAP 1。TBK 1的消耗或抑制显著提高了 YAP 1蛋白，选择性地在KRAS突变型肺癌细胞中。这是通过增强甲基化 精氨酸残基上的YAP 1。已知TBK 1在先天性免疫中起重要作用，但其致癌性 尤其是在肺癌领域的作用尚未完全阐明。我们的项目将调查 这种新的YAP 1蛋白的甘氨酸甲基化通过某些蛋白的甘氨酸甲基化的功能重要性 转移酶（PRMT），特别是PRMT 4/CARM 1和PRMT 5。通过泛PRMT抑制这些PRMT 抑制剂显著下调YAP 1的水平，即使在TBK 1耗尽的条件下。这些新颖 研究结果提出了同时抑制TBK 1和PRMT可能是一种可行的策略， 对抗NSCLC，我们将在一系列深入的体外和体内研究中对此进行研究。具体目标 （1）了解TBK 1在KRAS中对YAP 1的不同调节， EGFR突变型肺腺癌及（2）研究EGFR突变型肺腺癌中YAP 1分子的新甲基化状态， KRAS突变背景中的TBK 1耗竭导致YAP 1蛋白稳定性。

Lung cancer is the leading cause of cancer-related death in the United States, with a majority, around 85% resulting from non-small cell lung cancer (NSCLC). The overall survival rate for NSCLC is low, due to poor response to targeted therapy and the development of resistance. While immunotherapy is beneficial for about 30% of patients that harbor mutations in the KRAS oncogene, however, does not benefit the vast majority of the patients. In this context, studies showed that the transcriptional co-activator protein, YAP1, a downstream mediator of the Hippo signaling pathway, plays a major role in the stemness, growth, and metastasis of NSCLCs. In the present study, we find that a non-canonical I kinase, TBK1 (Tank-binding Kinase 1) can physically interact and phosphorylate YAP1. Depletion or inhibition of TBK1 significantly elevated the levels of the YAP1 protein, selectively in KRAS mutant lung cancer cells. This occurred through enhanced methylation of YAP1 on arginine residues. TBK1 is known to play an important role in innate immunity but its oncogenic role, especially in the field of lung cancer, is not fully elucidated. Our proposed project will investigate the functional importance of this novel arginine-methylation of YAP1 protein by certain protein arginine-methyl transferases (PRMTs), especially PRMT4/CARM1 and PRMT5. Inhibition of these PRMTs by a pan-PRMT inhibitor significantly downregulated the levels of YAP1 even in the TBK1 depleted condition. These novel findings raise the possibility that inhibiting TBK1 and PRMTs simultaneously might be a viable strategy to combat NSCLCs, and we will examine this in a series of in-depth in vitro and in vivo studies. The Specific Aims which will be covered are: (1) To understand the differential regulation of YAP1 by TBK1 in KRAS versus EGFR mutant lung adenocarcinoma and (2) To study the novel methylation status of YAP1 molecule under TBK1 depletion in KRAS mutant background leading to YAP1 protein stability.