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

项目总结/摘要 转移性黑色素瘤是超过80%的皮肤癌死亡的原因。我们实验室之前的研究 高转移性和低转移性黑色素瘤细胞之间的分子差异显示， 分泌蛋白载脂蛋白E（APOE）通过microRNA靶向在侵袭性黑素瘤中被抑制。 通过遗传和药理学方法拯救APOE表达抑制转移表型 以及黑色素瘤动物模型的存活率。特别是对侵袭表型的抑制， 发现由低密度脂蛋白受体相关蛋白1（LRP 1）介导，LRP 1是一种存在于 黑色素瘤细胞表面。然而，LRP 1与APOE合作以促进 黑色素瘤侵袭抑制仍然没有特征。这一建议旨在阐明分子 由这种APOE-LRP 1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通过激活黑色素瘤细胞来抑制黑色素瘤的侵袭性 LRP 1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 通过以下方法表征LRP 1缺失对APOE介导的转移抑制的功能后果： 在黑色素瘤细胞系中开发LRP 1基因敲除并进行转移测定，以及 转录组学分析。在目的2中，我将探讨LRP 1细胞内信号传导作为潜在的抑制性信号传导的作用。 通过在黑色素瘤细胞系中形成LRP 1信号转导突变体和 一种遗传小鼠黑色素瘤模型。这些研究的成功完成将揭示一种新的， 调节黑色素瘤转移的靶向信号通路，并将进一步加深我们对 APOE和LRP 1对癌症进展的影响。培训将在Sohail博士的实验室完成 Tavazoie和洛克菲勒大学和三机构MD的高度合作环境， 博士课程，并将集中在我的目标，成为一个独立的物理学家，科学家。

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.