Characterization of ILEI/LIFR Axis-induced Intracellular Signaling

项目摘要 我们的实验室以前已经确定了转化生长因子β（TGFβ）介导的 上皮间质转化（EMT）在小鼠乳腺上皮。我们已经证明， 白细胞介素样EMT诱导剂（ILEI）蛋白是诱导小鼠乳腺细胞中EMT所必需的 在接触TGFβ后。ILEI也被证明可以增加上皮细胞的自我更新能力 EMT后，通过其与白血病抑制因子受体（LIFR）的相互作用，表明 ILEI/LIFR信号轴促进乳腺癌干细胞（BCSC）表型。此外，我们的实验室已经表明， TGFβ诱导的LIFR上调是ILEI依赖性的。在源自小鼠肿瘤进展模型的细胞中 由我们的实验室创建，在非贴壁细胞培养条件下， ILEI或LIFR敲除。此外，ILEI或LIFR敲低的细胞原位移植物显示出 相对于对照细胞，肿瘤生长和转移减少。我们假设TGFβ诱导的LIFR 调节有助于转移。 ILEI介导的EMT和BCSC诱导的确切机制尚不清楚。在此，我们旨在 研究TGFβ暴露下游的ILEI/LIFR轴介导的机制，其影响（1）调节 LIFR蛋白表达和（2）随后的自我更新能力和疾病进展的维持 在我们的模型中。在具体目标1中，将检查LIFR启动子序列以鉴定调节LIFR启动子的关键因子。 LIFR表达。在特定目标2中，将在ILEI/LIFR敲除后检查转录组数据，以确定 ILEI/LIFR调节基因表达的特征及其与自我更新能力的关联。在特定 目的3，将在体内检查LIFR的作用，以确定其表达对细胞生长的影响。 在将细胞尾静脉注射到免疫缺陷小鼠中后，观察到肺肿瘤。 来自我们实验的数据将表征与BCSC维持相关的信号通路， 有可能发现新的治疗靶点。我们的发现可能会转化为休眠的新疗法 以及人类转移性乳腺癌的复发。

Project Summary Our lab has previously identified a mechanism of transforming growth factor beta (TGFβ)-mediated epithelial-to-mesenchymal transition (EMT) in murine mammary epithelium. We have shown that expression of the interleukin-like EMT inducer (ILEI) protein is necessary to induce EMT in murine mammary gland cells following exposure to TGFβ. ILEI has also been shown to increase the self-renewal capacity of epithelial cells following EMT, through its interaction with leukemia inhibitory factor receptor (LIFR), suggesting that the ILEI/LIFR signaling axis promotes breast cancer stem-cell (BCSC) phenotype. Further, our lab has shown that TGFβ-induced upregulation of LIFR is ILEI-dependent. In cells derived from a mouse tumor progression model created by our lab, spheroid formation capacity in non-adherent cell culture conditions is attenuated following either ILEI or LIFR knockdown. Additionally, orthotopic grafts of cells with ILEI or LIFR knockdown display a decrease in tumor growth and metastasis relative to control cells. We hypothesize that TGFβ-induced LIFR regulation contributes to metastases. The precise mechanisms of ILEI-mediated EMT and BCSC induction are unknown. Herein we aim to interrogate ILEI/LIFR axis-mediated mechanisms downstream of TGFβ exposure that influence (1) the regulation of LIFR protein expression and (2) the ensuing maintenance of self-renewal capacity and disease progression in our model. In Specific Aim 1, the LIFR promoter sequence will be examined to identify key factors regulating LIFR expression. In Specific Aim 2, transcriptomic data will be examined following ILEI/LIFR knockout to identify a signature of ILEI/LIFR-regulated gene expression and its association with self-renewal capacity. In Specific Aim 3, the role of LIFR will be examined in vivo to determine the impact of its expression upon outgrowth of pulmonary tumors following tail vein injection of cells into immunodeficient mice. Data from our experiments will characterize a signaling pathway associated with BCSC maintenance and will potentially identify novel therapeutic targets. Our findings may translate to novel treatments for dormancy and relapse in human metastatic breast cancer.