Lydic Todd A, Townsend Steven, Adda Christopher G, Collins Christine, Mathivanan Suresh, Reid Gavin E
Department of Physiology, Michigan State University, East Lansing, MI 48824, USA.
Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
Methods. 2015 Oct 1;87:83-95. doi: 10.1016/j.ymeth.2015.04.014. Epub 2015 Apr 20.
There is an increasing recognition of the role that cancer cell derived exosomes play in intercellular signaling upon fusion or uptake with a target cell, including immune system evasion, tumor growth and metastasis. To date, however, although exosomal membrane and cargo lipids are expected to play a pivotal role in exosome biogenesis and secretion, as well as in fusion or uptake and target cell functional response, the detailed characterization of cancer cell derived exosome lipids across a range of different cancers has not yet been broadly explored. Here, a simple and straightforward lipidome analysis strategy consisting of optimized sample extraction and novel sample derivatization techniques, coupled with high-resolution 'shotgun' mass spectrometry and 'targeted' tandem mass spectrometry methods, is demonstrated for the rapid identification of >520 individual lipids in 36 lipid classes and sub classes from exosomes secreted by the colorectal cancer cell line, LIM1215. Relative quantification and comparison of exosome versus cellular lipid profiles reveals significant enrichment of certain lipid classes, as well as substantial lipid subclass remodeling and changes in abundance of individual lipids, including sphingolipids, sterol lipids, glycerolipids and glycerophospholipids, and particularly plasmalogen- and alkyl ether-containing glycerophospholipids. This analysis strategy therefore provides a platform for comprehensive lipidome profiling across a wide range of cancer cell or tissue derived exosomes, that will facilitate subsequent functional studies aimed at elucidating the role of specific cellular or exosome lipids in the onset and progression of colorectal cancer, or to identify specific lipid(s) that could serve as effective diagnostic or prognostic disease biomarkers.
人们越来越认识到癌细胞衍生的外泌体在与靶细胞融合或被靶细胞摄取后在细胞间信号传导中所起的作用，包括逃避免疫系统、肿瘤生长和转移。然而，迄今为止，尽管外泌体膜和货物脂质有望在外泌体生物发生和分泌以及融合或摄取和靶细胞功能反应中发挥关键作用，但尚未广泛探索一系列不同癌症中癌细胞衍生外泌体脂质的详细特征。在此，展示了一种简单直接的脂质组分析策略，该策略包括优化的样品提取和新颖的样品衍生化技术，结合高分辨率“鸟枪法”质谱和“靶向”串联质谱方法，用于快速鉴定来自结肠癌细胞系LIM1215分泌的外泌体中36种脂质类别和亚类中的>520种单个脂质。外泌体与细胞脂质谱的相对定量和比较揭示了某些脂质类别的显著富集，以及大量的脂质亚类重塑和单个脂质丰度的变化，包括鞘脂、甾醇脂质、甘油脂和甘油磷脂，特别是含缩醛磷脂和烷基醚的甘油磷脂。因此，这种分析策略为广泛的癌细胞或组织衍生外泌体的综合脂质组分析提供了一个平台，这将有助于后续的功能研究，旨在阐明特定细胞或外泌体脂质在结直肠癌发生和发展中的作用，或鉴定可作为有效的疾病诊断或预后生物标志物的特定脂质。
