Abstract

Alterations in protein glycosylation in colorectal cancer (CRC) have been extensively studied using cell lines as models. However, little is known about their O-glycome and the differences in glycan biosynthesis in different cell types. To provide a better understanding of the variation in O-glycosylation phenotypes and their association with other molecular features, an in-depth O-glycosylation analysis of 26 different CRC cell lines was performed. The released O-glycans were analysed on porous graphitized carbon nano-liquid chromatography system coupled to a mass spectrometer via electrospray ionization (PGC-nano-LC–ESI-MS/MS) allowing isomeric separation as well as in-depth structural characterization. Associations between the observed glycan phenotypes with previously reported cell line transcriptome signatures were examined by canonical correlation analysis. Striking differences are observed between the O-glycomes of 26 CRC cell lines. Unsupervized principal component analysis reveals a separation between well-differentiated colon-like and undifferentiated cell lines. Colon-like cell lines are characterized by a prevalence of I-branched and sialyl Lewis x/a epitope carrying glycans, while most undifferentiated cell lines show absence of Lewis epitope expression resulting in dominance of truncated α2,6-core sialylated glycans. Moreover, the expression of glycan signatures associates with the expression of glycosyltransferases that are involved in their biosynthesis, providing a deeper insight into the regulation of glycan biosynthesis in different cell types. This untargeted in-depth screening of cell line O-glycomes paves the way for future studies exploring the role of glycosylation in CRC development and drug response leading to discovery of novel targets for the development of anti-cancer antibodies.

中文翻译：

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结直肠癌细胞系表现出惊人的 O-糖组多样性，反映了细胞分化表型

 抽象的

结直肠癌 (CRC) 中蛋白质糖基化的改变已使用细胞系作为模型进行了广泛研究。然而，人们对它们的O-糖组以及不同细胞类型中聚糖生物合成的差异知之甚少。为了更好地了解O-糖基化表型的变化及其与其他分子特征的关联，对 26 种不同的 CRC 细胞系进行了深入的O-糖基化分析。释放的O-聚糖在多孔石墨化碳纳米液相色谱系统上进行分析，该系统通过电喷雾电离（PGC-nano-LC-ESI-MS/MS）与质谱仪联用，从而实现异构体分离和深入的结构表征。通过典型相关分析检查了观察到的聚糖表型与先前报道的细胞系转录组特征之间的关联。在 26 种 CRC 细胞系的O-糖组之间观察到显着差异。无监督的主成分分析揭示了分化良好的结肠样细胞系和未分化细胞系之间的分离。结肠样细胞系的特征是普遍存在 I 分枝和唾液酸化 Lewis x/a 表位，而大多数未分化细胞系缺乏 Lewis 表位表达，导致截短的 α2,6 核心唾液酸化聚糖占主导地位。此外，聚糖特征的表达与参与其生物合成的糖基转移酶的表达相关，从而可以更深入地了解不同细胞类型中聚糖生物合成的调节。 这种对细胞系O-糖组的非针对性深入筛选为未来探索糖基化在CRC发展和药物反应中的作用的研究铺平了道路，从而发现了抗癌抗体开发的新靶点。