Intrahepatic cholangiocarcinoma (ICC) is the second major subtype of primary liver cancer and has caused more and more attention with increasing incidence and mortality worldwide. Our previous study found that bisecting N-glycans are commonly increased in ICC, while the effects and potential functions of bisecting GlcNAc in ICC are still largely unclear. In this study, we further confirmed that the structures of bisecting GlcNAc were significantly up-regulated in ICC compared with paracancer tissues by glycoproteomic data and lectin histochemistry. The expression of its glycosyltransferase MGAT3 was also up-regulated in ICC tissues at both mRNA and protein levels, and expression of MGAT3 is negatively correlated with overall survival explored by bioinformatic analyses and published datasets from 255 patients. Next, the silencing of MGAT3 could inhibit the growth and invasion of ICC cells, and overexpressing of MGAT3 only promoted ICC cell invasion. Further glycoproteomic analysis showed that the commonly glycoproteins modified by bisecting GlcNAc after MGAT3-overexpression in two ICC cell lines were mainly involved in cell movement-related biological processes, such as cell adhesion, integrin-related and ECM-receptor interaction. This study sheds light on the potential effects of bisecting GlcNAc in ICC cells and suggests that MGAT3 might be used as a potential target in the therapy of ICC.

肝内胆管癌（intrahepatic cholangiocarcinoma，ICC）是原发性肝癌的第二大亚型，随着全球发病率和死亡率的上升，越来越受到人们的关注。我们之前的研究发现，在 ICC 中平分N-聚糖通常会增加，而在 ICC 中平分 GlcNAc 的影响和潜在功能在很大程度上仍不清楚。在这项研究中，我们通过糖蛋白组学数据和凝集素组织化学进一步证实，与癌旁组织相比，ICC 中二等分 GlcNAc 的结构显着上调。其糖基转移酶 MGAT3 的表达在 ICC 组织中的 mRNA 和蛋白水平也上调，并且MGAT3的表达与通过生物信息学分析和 255 名患者的已发表数据集探索的总体生存率呈负相关。接下来，MGAT3的沉默可以抑制ICC细胞的生长和侵袭，而MGAT3的过表达只会促进ICC细胞的侵袭。进一步的糖蛋白组学分析表明，在两种 ICC 细胞系中MGAT3过表达后，通过平分 GlcNAc 修饰的常见糖蛋白主要参与细胞运动相关的生物学过程，例如细胞粘附、整合素相关和 ECM 受体相互作用。这项研究揭示了 ICC 细胞中二等分 GlcNAc 的潜在影响，并表明MGAT3可能用作 ICC 治疗的潜在靶点。