Effects of Polymeric Mucin Expression on Lung Carcinogenesis

肺癌是癌症相关死亡的主要原因，退伍军人的风险不成比例地高。 肺腺癌（LUAD）占所有肺癌病例的一半，但缺乏有效的治疗方法， 部分原因是对LUAD生物学的不完全理解。LUAD肿瘤起源于气道分泌型 上皮细胞和粘蛋白表达是普遍的，并与LUAD侵袭性相关。然而，在这方面， 粘蛋白影响LUAD发病机制的机制知之甚少。的总体概念 这一建议是LUAD中异常的上皮生长被两种多聚粘蛋白MUC 5AC和 MUC5B。MUC 5AC和MUC 5 B在健康人气道防御中是必需的，但在LUAD中表达异常， 与侵袭性、复发和死亡率相关，特别是在具有激活突变的患者中， KRAS-LUAD最常见的致癌驱动因子。我们验证了MUC 5AC在氨基甲酸乙酯中的因果关系， LUAD的活化Kras表达小鼠模型。在缺乏Muc 5ac的动物中（“MUC”在人类中，“Muc”在人类中）， 小鼠），肿瘤数量和大小减少约50%。Muc 5 b自身的相对促肿瘤作用 或与Muc 5ac的关系尚不清楚。我们在这里试图缩小这一重要性差距。我们还试图确定 聚合粘蛋白介导的肿瘤促进的分子机制。我们和其他人的研究 鉴定了许多刺激LUAD的信号，包括粘液性LUAD亚型。上游信号传导 途径集中于粘蛋白及其生物合成机制。单个MUC 5AC和MUC 5 B分子 非常大。它们多聚化，通过添加糖， 它们的中心糖基化结构域。因此，蛋白质稳态（蛋白质稳态）在体内过程中受到严格调节。 聚合粘蛋白生物合成。粘蛋白的翻译、折叠和二聚化发生在内质网中 (ER)并涉及数百个二硫键的形成。为了满足这些需求，哺乳动物表达了一种 ER应激传感器肌醇需要酶-1（IRE-1，也称为ER-to- 核信号蛋白或ERN）。ERN 1广泛表达，对ER应激触发的 细胞凋亡，但称为ERN 2的同种型仅限于粘液细胞，在那里它是维持粘蛋白所必需的 尽管高水平的ER应激，但仍然可以合成。这种适应是通过ERN 2直接结合到 ERN 1和ERN 1介导的促凋亡信号传导的后续抑制。虽然对宿主有利 在健康防御中，凋亡抑制可能在LUAD中是有害的。我们假设MUC 5AC和 MUC 5 B通过ERN 2依赖性抑制ER应激诱导的LUAD中的上皮细胞生长 凋亡提出了以下三个具体目的：1）检验MUC 5AC/Muc 5ac和MUC 5AC/Muc 5ac的假设。 MUC 5 B/Muc 5 b促进LUAD和粘液性LUAD; 2）检验多聚粘蛋白表达促进LUAD和粘液性LUAD的假设。 在肿瘤细胞中通过ERN 2/Ern 2依赖性蛋白质稳态功能障碍促进LUAD; 3）检验以下假设： 多聚粘蛋白表达促进ERN 2/Ern 2依赖性上皮生长。研究将利用新的 小鼠模型、细胞系和患者样本，重点关注粘蛋白、ER 压力和LUAD。创新的基因编辑工具将沿着药物， 将应用最先进的动物、组织和分子成像技术。 这些目标的实现有可能对退伍军人及其家人的生活产生重大影响。我们 团队由粘蛋白和癌细胞生物学专家组成，他们具有独特的优势，可以解决问题 这将提高我们对KRAS引起的LUAD的理解。研究结果可以鉴定MUC 5AC、MUC 5 B和MUC 5C。 ERN 2作为直接限制LUAD生长的靶点，并改善这种常见但治疗效果差的疾病的治疗策略。 肺癌的症状

Lung cancer is the leading cause of cancer-related deaths, and risks are disproportionately high in veterans. Lung adenocarcinoma (LUAD) accounts for half of all lung cancer cases, but effective treatments are lacking in part due to an incomplete understanding of LUAD biology. LUAD tumors originate from airway secretory epithelia, and mucin expression is prevalent and associated with LUAD aggressiveness. However, mechanisms by which mucins affect LUAD pathogenesis are poorly understood. The overarching concept of this proposal is that aberrant epithelial growth in LUAD is potentiated by two polymeric mucins--MUC5AC and MUC5B. Though required for airway defense in health, MUC5AC and MUC5B misexpression in LUAD correlates with invasiveness, recurrence, and mortality, especially in patients with activating mutations in KRAS--the most common oncogenic driver of LUAD. We validated MUC5AC causatively in urethane and activated-Kras expression mouse models of LUAD. In animals lacking Muc5ac (‘MUC in humans, ‘Muc’ in mice), tumor number and size decreased by ~50%. The relative tumor-promoting effects of Muc5b on its own or with Muc5ac are not yet known. We seek to close this significance gap here. We also seek to determine molecular mechanisms for polymeric mucin-mediated tumor promotion. Studies by us and by others have identified numerous signals that stimulate LUAD, including mucinous LUAD subtypes. Upstream signaling pathways converge on mucins and their biosynthetic machinery. Individual MUC5AC and MUC5B molecules are extraordinarily large. They multimerize, and they become even more massive through addition of sugars to their central glycosylation domains. Accordingly, protein homeostasis (proteostasis) is tightly regulated during polymeric mucin biosynthesis. Mucin translation, folding, and dimerization occur in the endoplasmic reticulum (ER) and involve formation of hundreds of disulfide bonds. To handle these demands, mammals express a mucous cell specific isoform of the ER stress sensor inositol-requiring enzyme-1 (IRE-1, also called ER-to- nucleus signaling protein, or ERN). ERN1 is ubiquitously expressed and is crucial for ER stress-triggered apoptosis, but an isoform called ERN2 is restricted to mucous cells where it is required for sustaining mucin synthesis despite high levels of ER stress. This adaptation is accomplished by direct binding of ERN2 to ERN1 and subsequent suppression of ERN1-mediated pro-apoptotic signaling. While beneficial for host defense in health, apoptosis suppression could be detrimental in LUAD. We hypothesize that MUC5AC and MUC5B promote epithelial cell growth in LUAD via ERN2-dependent suppression of ER stress-induced apoptosis. The following three Specific Aims are proposed: 1) Test the hypothesis that MUC5AC/Muc5ac and MUC5B/Muc5b promote LUAD and mucinous LUAD; 2) Test the hypothesis that polymeric mucin expression in tumor cells promotes LUAD via ERN2/Ern2 dependent proteostasis dysfunction; 3) Test the hypothesis that polymeric mucin expression promotes ERN2/Ern2-dependent epithelial growth. Studies will utilize novel mouse models, cell lines, and patient samples to focus on significant causative links between mucins, ER stress, and LUAD. Innovative gene-editing tools will be used along with pharmacologic agents as interventions, and state of the art animal, tissue, and molecular imaging techniques will be applied. Completion of these aims has the potential to significantly impact the lives of veterans and their families. Our team comprises experts in mucin and cancer cell biology who are uniquely positioned to address questions that will improve our understanding of KRAS-induced LUAD. Findings could identify MUC5AC, MUC5B, and ERN2 as targets to directly limit LUAD growth and to improve strategies for this common but poorly treatable form of lung cancer.