The role of lipids in melanoma progression via induction of ER stress and lipid droplet formation

项目总结 黑色素瘤是最致命的皮肤癌，进展为转移性疾病会导致 病人存活率。肿瘤微环境(TME)在支持肿瘤生长和治疗中发挥着重要作用 促进癌症转移。我们实验室最近发现TME脂肪细胞可以直接转移脂肪 酸进入黑色素瘤细胞并促进侵袭。脂肪酸可以作为一种多用途的积木来受益 但过量的脂肪酸也会引发内质网(ER)应激。越来越多的证据表明 内质网应激可以诱导癌细胞的侵袭和生存程序，导致转移，但其机制是通过 目前还不清楚这种情况会发生在什么地方。我们的初步数据表明，脂肪细胞衍生的脂类诱导内质网应激 这促进了入侵基因计划。在目标1中，我们将研究脂质诱导的内质网应激在 转移。我们将从机械上剖析脂肪细胞衍生的脂质诱导的内质网应激途径， 并描述内质网应激是如何上调典型的黑色素瘤侵袭基因以促进转移的。我们 假设脂质诱导IRE和PERK，这是ER应激的两个分支，以前与癌症有关 AXL是一种潜在的黑色素瘤侵袭基因，可促进黑色素瘤的侵袭。而ER 压力可以上调有利于癌症的细胞生存计划，持续的内质网应激会导致细胞死亡。至 由于脂质过载，细胞可以形成脂滴(LD)，这是胞浆细胞器，以对抗内质网应激 含有中性脂核的。LDS可以保护细胞免受脂类毒副作用的影响，并发挥调节来源的作用 脂类的可及性。在目标2中，我们将研究LDS如何保护癌细胞免受脂质介导的压力。 我们将研究LDS缓解内质网应激的机制，并确定它们在促进 癌症转移。我们假设LDS通过将脂类隔离在内质网管腔外来减轻内质网应激，并 将脂类分门别类地用作癌症进展的燃料。我们将同时利用人类和斑马鱼 黑色素瘤细胞在内质网应激和LD形成途径中产生遗传扰动，以便 了解这两种机制如何支持黑色素瘤的进展。我们将在中国进行肿瘤移植 斑马鱼和应用计算机图像分析来研究这些途径在促进 体内转移。这些结合的方法将导致对内质网应激和LD形成的新见解 癌症转移机制，这可以确定阻止黑色素瘤进展的新策略。

PROJECT SUMMARY Melanoma is the most lethal skin cancer, and progression to metastatic disease leads to severe reduction in patient survival. The tumor microenvironment (TME) plays a significant role in supporting tumor growth and promoting cancer metastasis. Our laboratory recently discovered that TME adipocytes can directly transfer fatty acids into melanoma cells and promote invasion. Fatty acids can serve as a multipurpose building block to benefit cells, but excess fatty acids can also trigger endoplasmic reticulum (ER) stress. Growing evidence suggests that ER stress can induce cancer cell invasion and survival programs leading to metastasis, but the mechanism by which this occurs remains unclear. Our preliminary data suggests that adipocyte-derived lipids induce ER stress which promotes invasion gene programs. In Aim 1, we will investigate the role of lipid induced ER stress in metastasis. We will mechanistically dissect which ER stress pathways are induced by adipocyte derived lipids, and characterize how ER stress upregulates canonical melanoma invasion genes to facilitate metastasis. We hypothesize that lipids induce IRE and PERK, two branches of ER stress previously linked with cancer metastasis, and promotes melanoma invasion through AXL, a potential melanoma invasion gene. While ER stress can upregulate cell survival programs that can benefit cancer, persistent ER stress leads to cell death. To combat ER stress due to lipid overload, cells can form lipid droplets (LD) which are cytosolic organelles containing a neutral lipid core. LDs can protect cells from toxic side effects of lipids and act a regulated source of lipid accessibility. In Aim 2, we will examine how LDs protect cancer cells against lipid mediated stress. We will investigate the mechanism by which LDs can alleviate ER stress and determine their role in promoting cancer metastasis. We hypothesize that LDs reduce ER stress by sequestering lipids out of the ER lumen and compartmentalize lipids to be used as fuel for cancer progression. We will utilize both human and zebrafish melanoma cells to generate genetic perturbations within ER stress and LD formation pathways in order to understand how these two mechanisms support melanoma progression. We will perform tumor transplants in zebrafish and apply computational image analysis to investigate the role of these pathways in promoting metastasis in vivo. These combined approaches will lead to novel insights into ER stress and LD formation as mechanisms of cancer metastasis, which can identify new strategies to block melanoma progression.