Microscopic imaging mass spectrometry assisted by on- tissue chemical derivatization for visualizing multiple amino acids in human colon cancer xenografts
Microscopic imaging mass spectrometry assisted by on- tissue chemical derivatization for visualizing multiple amino acids in human colon cancer xenografts
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DOI：
10.1002/pmic.201300041
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发表时间：
2014-04-01
期刊：
影响因子：
3.4
通讯作者：
Suematsu, Makoto
中科院分区：
文献类型：
--
作者：
Toue, Sakino;Sugiura, Yuki;Suematsu, Makoto
成像MS与CE/MS相结合，可以提供组织切片中小分子代谢物的半定量和空间信息。然而，由于MALDI-MS的电离效率较低，包括氨基酸在内的所有代谢物都没有被完全可视化。本研究的目的是获得冷冻组织切片中多种氨基酸的半定量空间信息。以对-N，N，N-三甲基氨基-N-羟基丁二酰亚胺基氨基甲酸酯(TaHS)为衍生化试剂，提高了其电离效率和检测灵敏度。半定量MALDI成像MS使我们能够使用超免疫缺陷NOD/SCID/(NULL)小鼠(NOG小鼠)的肝转移模型来可视化和量化人结肠癌异种移植瘤中的游离氨基酸池。由于几种Tahs衍生氨基酸的m/z值与2，5-二羟基苯甲酸和其他内源性化合物的m/z值重叠，我们用串联质谱仪对它们进行了成像。结果表明，转移性肿瘤的局部谷氨酸、谷氨酰胺、甘氨酸、亮氨酸/异亮氨酸/羟脯氨酸、苯丙氨酸和丙氨酸的含量显著高于荷瘤肝脏实质。因此，组织上Tahs衍生化是一种有用的方法来检测体内许多氨基酸水平的变化，从而能够理解这些代谢物在包括癌症在内的各种疾病条件下的空间变化。
Imaging MS combined with CE/MS serves as a method to provide semi-quantitative and spatial information of small molecular metabolites in tissue slices. However, not all metabolites including amino acids have fully been visualized, because of low-ionization efficiency in MALDI MS. This study aimed to acquire semi-quantitative spatial information for multiple amino acids in frozen tissue slices. As a derivatization reagent, p-N,N,N-trimethylammonioanilyl N-hydroxysuccinimidyl carbamate iodide (TAHS) was applied to increase their ionization efficiency and detection sensitivity. Semi-quantitative MALDI-imaging MS allowed us to visualize and quantify free amino acid pools in human colon cancer xenografts using a model of liver metastases in super-immunodeficient NOD/scid/(null) mice (NOG mice). Because the m/z values of several TAHS-derivatized amino acids overlap with those of the 2,5-dihydroxybenzoic acid background and other endogenous compounds, we imaged them with tandem MS. The results indicated that regional contents of glutamate, glutamine, glycine, leucine/isoleucine/hydroxyproline, phenylalanine, and alanine were significantly elevated in metastatic tumors versus parenchyma of tumor-bearing livers. On-tissue TAHS derivatization thus serves as a useful method to detect alterations in many amino acid levels in vivo, thereby enabling understanding of the spatial alterations of these metabolites under varied disease conditions including cancer.