Targeting the LIFR-LCN2 pathway to improve liver cancer therapy

项目摘要/摘要 铁对许多生理过程都是至关重要的，但过量的铁会造成毒性。铁稳态失调 (无论是缺铁还是超负荷)是病理状态的先兆。肝脏将铁储存在肝细胞中。 是控制全身铁稳态的主要器官。肝癌，主要是肝细胞癌 (肝细胞癌)，是高度致命的，治疗选择有限，也没有生物标志物来预测治疗反应。白血病 抑制因子受体(LIFR)在人肝细胞癌中经常下调；然而，体内和遗传学研究 缺乏LIFR在肝癌发生发展和治疗反应中的作用。最近，通过构建 对肝细胞特异的和可诱导的LIFR基因敲除小鼠的特征，我们发现LIFR的缺失促进了肝脏的生长 肿瘤的发生和对索拉非尼诱导的铁下垂的抵抗，铁下垂是一种非凋亡性细胞死亡类型 以铁依赖的过氧化脂质堆积为特征。我们的数据还表明， LIFR抑制肝脏中的NF-κB信号，进而下调Lipocalin 2(Lcn2)，一种铁- 隔离细胞因子。同时，我们的数据显示，在癌基因诱导的肝肿瘤中，过表达的 LIFR增加，而LIFR基因敲除后CD8+T细胞浸润减少，这可能是通过Lcn2- 依赖下调铁水平、T细胞的活性和增殖。总而言之，这些数据支持 假设LIFR在肝癌中缺失或下调导致Lcn2上调，一方面，Lcn2 赋予肝脏肿瘤细胞对铁性下垂的抵抗力，另一方面，剥夺T细胞的铁，即 对T细胞活性、增殖和效应器功能至关重要；这两种机制都会导致肝癌 进展和治疗耐药。在这项拟议的工作中，我们将阐明 LIFR抑制肝细胞中的NF-κB信号转导(特异性目标1)。此外，我们将调查Lcn2是否可以提供 作为提高索拉非尼治疗肝癌疗效的治疗靶点(特定目标2)。最后，我们将研究是否 LIFR或治疗性Lcn2中和可使肝癌对免疫治疗敏感(特定目标3)。从基因上讲 转基因小鼠模型，睡美人转座子介导的癌基因诱导的肝癌模型，以及 肝细胞癌患者来源的异种移植模型将被用于研究治疗潜力和作用机制。 两种新的药物组合，这将阐明如何通过靶向铁来改善肝癌的治疗- 隔离途径。我们设想可以使用低LIFR表达和高Lcn2表达来选择 可能从Lcn2中和抗体加Lcn2联合治疗中受益的肝癌患者 索拉非尼或免疫检查点抑制剂。

PROJECT SUMMARY/ABSTRACT Iron is vital for many physiological processes, but excessive iron causes toxicity. Dysregulated iron homeostasis (either iron deficiency or overload) is a harbinger of pathological conditions. The liver stores iron in hepatocytes and is the major organ that controls systemic iron homeostasis. Liver cancer, primarily hepatocellular carcinoma (HCC), is highly lethal with limited treatment options and no biomarkers to predict therapy response. Leukemia inhibitory factor receptor (LIFR) is frequently downregulated in human HCC; however, in vivo and genetic studies of LIFR’s functions in liver cancer development and therapy response were lacking. Recently, by constructing and characterizing hepatocyte-specific and inducible Lifr-knockout mice, we found that loss of Lifr promoted liver tumorigenesis and conferred resistance to sorafenib-induced ferroptosis, a non-apoptotic type of cell death characterized by the iron-dependent accumulation of lipid hydroperoxides. Our data also pointed to a role for LIFR in inhibiting NF-κB signaling in the liver, which in turn downregulates lipocalin 2 (LCN2), an iron- sequestering cytokine. In parallel, our data revealed that in oncogene-induced liver tumors, overexpression of LIFR increased, while knockout of Lifr decreased CD8+ T cell infiltration, which may be mediated by LCN2- dependent downregulation of iron levels, viability, and proliferation of T cells. Altogether, these data support a hypothesis that loss or downregulation of LIFR in liver cancer leads to upregulation of LCN2, which on one hand confers resistance to ferroptosis on liver tumor cells, and on the other hand, deprives T cells of iron that is essential for T cell viability, proliferation, and effector function; both mechanisms contribute to liver cancer progression and therapy resistance. In the proposed work, we will elucidate the molecular mechanisms by which LIFR inhibits NF-κB signaling in liver cells (Specific Aim 1). Further, we will investigate whether LCN2 can serve as a therapeutic target for enhancing sorafenib efficacy in HCC (Specific Aim 2). Finally, we will study whether LIFR or therapeutic LCN2 neutralization can sensitize HCC to immunotherapy (Specific Aim 3). Genetically engineered mouse models, Sleeping Beauty transposon-mediated oncogene-induced liver cancer models, and HCC patient-derived xenograft models will be used to study the therapeutic potential and mechanisms of action of two novel drug combinations, which will illuminate how to improve liver cancer therapy by targeting an iron- sequestering pathway. We envision that low LIFR expression and high LCN2 expression could be used to select HCC patients who will likely benefit from the combination therapy with the LCN2-neutralizing antibody plus sorafenib or immune checkpoint inhibitors.