Elucidating the Function of LRP1 in APOE-mediated Suppression of Melanoma Metastasis

项目摘要/摘要 转移性黑色素瘤是超过80%的皮肤癌死亡的原因。我们实验室以前的工作是审问 高转移黑色素瘤细胞和低转移黑色素瘤细胞之间的分子差异表明， 分泌蛋白载脂蛋白E(APOE)在侵袭性黑色素瘤中通过microRNA靶向被抑制。 通过遗传学和药理学方法挽救载脂蛋白E的表达可抑制转移表型 并延长黑色素瘤动物模型的存活时间。尤其是对侵袭表型的抑制 发现是由低密度脂蛋白受体相关蛋白1(LRP1)介导的，低密度脂蛋白受体1是一种存在于 黑色素瘤细胞表面。然而，LRP1与APOE合作的机制 对黑色素瘤侵袭的抑制作用仍未明确。这项提议试图阐明分子 这种APOE-LRP1相互作用引发的改变导致黑色素瘤侵袭能力的丧失。基于 文献证据和初步数据，我假设APOE通过激活ApoE抑制黑色素瘤的侵袭性 LRP1信号轴。这一假设将通过以下两个目标进行检验：在目标1中，我将充分 表征LRP1缺失在载脂蛋白E介导的转移抑制中的功能后果 在黑色素瘤细胞系中开发LRP1基因敲除，并进行转移分析以及 转录分析。在目标2中，我将探索LRP1细胞内信号作为一种潜在的抑制信号的作用 在黑色素瘤细胞系和黑色素瘤细胞中开发LRP1信号突变体的APOE结合下游机制 遗传性小鼠黑色素瘤模型。这些研究的成功完成将揭示一种新的治疗方法 调节黑色素瘤转移的靶向信号通路，并将加深我们对 载脂蛋白E和LRP1对肿瘤进展的影响。培训将在索海尔博士的实验室完成 Tavazoie和洛克菲勒大学和三所学院MD的高度合作环境- 博士项目，并将围绕我成为一名独立的内科科学家的目标。

PROJECT SUMMARY/ABSTRACT Metastatic melanoma is the cause of over 80% of skin cancer deaths. Previous work in our lab interrogating the molecular differences between highly and poorly metastatic melanoma cells revealed that expression of the secreted protein apolipoprotein E (APOE) is repressed in aggressive melanomas through microRNA targeting. Rescuing APOE expression through genetic and pharmacologic approaches suppresses metastatic phenotypes and prolongs survival in melanoma animal models. Suppression of the invasion phenotype in particular was found to be mediated by low-density lipoprotein receptor-related protein 1 (LRP1), an APOE receptor present on the melanoma cell surface. However, the mechanisms by which LRP1 cooperates with APOE to facilitate inhibition of melanoma invasion remain uncharacterized. This proposal seeks to elucidate the molecular alterations initiated by this APOE-LRP1 interaction that result in loss of melanoma invasive capacity. Based on literature evidence and preliminary data, I hypothesize that APOE inhibits melanoma invasiveness by activating an LRP1 signaling axis. This hypothesis will be tested through the following two aims: In Aim 1, I will fully characterize the functional consequences of LRP1 loss on APOE-mediated metastasis suppression by developing LRP1 genetic knockouts in melanoma cell lines and performing metastasis assays as well as transcriptomic analysis. In Aim 2, I will explore the role of LRP1 intracellular signaling as a potential suppressive mechanism downstream of APOE binding by developing LRP1 signaling mutants in melanoma cell lines and in a genetic mouse melanoma model. Successful completion of these studies will uncover a novel, therapeutically targetable signaling pathway that regulates melanoma metastasis and will further our understanding of the influences of APOE and LRP1 on cancer progression. Training will be completed in the laboratory of Dr. Sohail Tavazoie and the highly collaborative environments of The Rockefeller University and the Tri-Institutional MD- PhD Program, and will be centered on my goal of becoming an independent physician-scientist.