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

项目概要 黑色素瘤是最致命的皮肤癌，进展为转移性疾病会导致黑色素瘤严重减少 患者生存。肿瘤微环境（TME）在支持肿瘤生长和 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构建模块来受益 细胞，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 ER应激可以诱导癌细胞侵袭和生存程序导致转移，但其机制是 发生这种情况的原因尚不清楚。我们的初步数据表明脂肪细胞来源的脂质会诱导内质网应激 促进入侵基因程序。在目标 1 中，我们将研究脂质诱导的 ER 应激在 转移。我们将机械地剖析哪些内质网应激途径是由脂肪细胞衍生的脂质诱导的， 并描述内质网应激如何上调经典黑色素瘤侵袭基因以促进转移。我们 假设脂质会诱导 IRE 和 PERK，这是先前与癌症相关的 ER 应激的两个分支 转移，并通过潜在的黑色素瘤侵袭基因 AXL 促进黑色素瘤侵袭。而急诊室 压力可以上调细胞生存程序，从而有益于癌症，持续的内质网压力会导致细胞死亡。至 为了对抗脂质超载引起的内质网应激，细胞可以形成脂滴 (LD)，这是细胞质细胞器 含有中性脂质核心。 LD 可以保护细胞免受脂质的毒副作用，并充当受监管的来源 脂质可及性。在目标 2 中，我们将研究 LD 如何保护癌细胞免受脂质介导的应激。 我们将研究 LD 缓解 ER 应激的机制，并确定其在促进 癌症转移。我们假设 LD 通过将脂质隔离出 ER 腔来减轻 ER 应激， 将脂质划分为癌症进展的燃料。我们将利用人类和斑马鱼 黑色素瘤细胞在 ER 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。我们将进行肿瘤移植手术 斑马鱼并应用计算图像分析来研究这些途径在促进 体内转移。这些组合方法将对 ER 应激和 LD 形成产生新的见解 癌症转移的机制，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.