OST Inhibition in NSCLC

非小细胞肺癌（NSCLC）是侵袭性肿瘤，是发病率和死亡率的主要原因 在美国在过去的十年中，系统治疗的引入，如受体酪氨酸 激酶靶向抑制剂和免疫检查点抑制剂显著改善了患者的结果。 然而，对这些疗法的治疗抗性经常发展，并且其特征在于平行的免疫抑制。 通过其他共表达的受体糖蛋白进行信号传导。因此，我们研究了 破坏天冬酰胺（N）连接的糖基化，一种共翻译和翻译后蛋白质修饰，作为一种策略， 阻断NSCLC中的主要和旁路糖蛋白存活信号传导。虽然这条途径是目标 丰富，涉及至少34种基因产物，调节这一过程的药理学抑制剂没有 以前可用。我们已经确定了第一类小分子抑制剂， 寡糖基转移酶（OST），将聚糖转移至延伸酶的多亚基酶复合物， 内质网中的蛋白质。这种抑制剂通过靶向催化亚基降低OST保真度， 导致糖基化的位点特异性和部分抑制。在RTK依赖性激活的NSCLC中 致癌信号传导，OST抑制阻断肿瘤细胞增殖，并有利地与TKI偶联，以增强肿瘤细胞的增殖。 细胞凋亡和异种移植肿瘤生长。我们现在提出表征和发展新型小分子 OST抑制剂的催化亚基抑制和对EGFR驱动的NSCLC的作用。因为 糖蛋白旁路信号在伴有FGFR 1扩增或KRAS的NSCLC亚型中也起作用 突变，我们将定义信号传导机制，并确定这些肿瘤对OST的敏感性 抑制作用本项目还将研究OST抑制对NSCLC放射敏感性的影响，并确定 糖蛋白依赖性细胞程序如何介导内在和免疫介导的治疗抗性。 总之，这项工作将推进OST抑制作为NSCLC的一种新的治疗策略， 提供一种可用于临床的OST抑制剂。

Non-small cell lung cancers (NSCLC) are aggressive tumors that are a major cause of morbidity and mortality in the United States. In the past decade, the introduction of systemic therapies such as receptor tyrosine kinase targeted inhibitors and immune checkpoint inhibitors have significantly improved patient outcomes. However, therapeutic resistance to these therapies frequently develops and is characterized by parallel signaling through other co-expressed receptor glycoproteins. We have therefore investigated the feasibility of disrupting asparagine (N) linked glycosylation, a co- and post-translational protein modification, as a strategy to block both primary and bypass glycoprotein survival signaling in NSCLC. Although this pathway is target rich and involves at least 34 gene products, pharmacologic inhibitors that regulate this process have not previously been available. We have identified a first in class small molecule inhibitor of the oligosaccharyltransferase (OST), the multi-subunit enzymatic complex that transfers glycans to elongating proteins in the endoplasmic reticulum. This inhibitor reduces OST fidelity by targeting the catalytic subunit and results in a site-specific and partial inhibition of glycosylation. In NSCLC with activation of RTK dependent oncogenic signaling, OST inhibition blocks tumor cell proliferation and couples favorably with TKIs to enhance apoptosis and xenograft tumor growth. We now propose to characterize and advance novel small molecule inhibitors of the OST with respect to catalytic subunit inhibition and effects on EGFR driven NSCLC. Because glycoprotein bypass signaling is also operative in NSCLC subtypes with FGFR1 amplification or KRAS mutation, we will define the signaling mechanisms and determine the sensitivity of these tumors to OST inhibition. This project will also investigate the effects of OST inhibition on NSCLC radiosensitivity and identify how glycoprotein dependent cellular programs mediate intrinsic and immune mediated therapeutic resistance. Together this work will advance OST inhibition as a novel treatment strategy for NSCLC with the potential of delivering an OST inhibitor that can be translated to the clinic.