Beta1,4-galactosyltransferases (B4GALTs) play a crucial role in several diseases, including cancer. B4GALT1 is highly expressed in the liver, and patients with mutations in B4GALT1 exhibit hepatopathy. However, the role of B4GALT1 in liver cancer remains unclear. Here, we found that B4GALT1 was significantly downregulated in hepatocellular carcinoma (HCC) tissue compared with the adjacent liver tissue, and low B4GALT1 expression was associated with vascular invasion and poor overall survival in patients with HCC. Additionally, silencing or loss of B4GALT1 enhanced HCC cell migration and invasion in vitro and promoted lung metastasis of HCC in NOD/SCID mice. Moreover, B4GALT1 knockdown or knockout increased cell adhesion to laminin, whereas B4GALT1 overexpression decreased the adhesion. Through a mass spectrometry-based approach and Griffonia simplicifolia lectin II (GSL-II) pull-down assays, we identified integrins α6 and β1 as the main protein substrates of B4GALT1 and their N-glycans were modified by B4GALT1. Further, the increased cell migration and invasion induced by B4GALT1 knockdown or knockout were significantly reversed using a blocking antibody against integrin α6 or integrin β1. These results suggest that B4GALT1 downregulation alters N-glycosylation and enhances the laminin-binding activity of integrin α6 and integrin β1 to promote invasiveness of HCC cells. Our findings provide novel insights into the role of B4GALT1 in HCC metastasis and highlight targeting the laminin-integrin axis as a potential therapeutic strategy for HCC with low B4GALT1 expression.

Beta1,4-半乳糖基转移酶 (B4GALT) 在包括癌症在内的多种疾病中发挥着至关重要的作用。B4GALT1在肝脏中高表达，B4GALT1突变的患者会出现肝病。然而，B4GALT1 在肝癌中的作用仍不清楚。在这里，我们发现与邻近的肝组织相比，B4GALT1在肝细胞癌（HCC）组织中显着下调，并且B4GALT1低表达与HCC患者的血管侵犯和较差的总生存期相关。此外，B4GALT1的沉默或缺失增强了HCC细胞的体外迁移和侵袭，并促进了NOD/SCID小鼠中HCC的肺转移。此外，B4GALT1 敲低或敲除增加了细胞对层粘连蛋白的粘附，而 B4GALT1 过表达则降低了粘附。通过基于质谱的方法和加纳单叶凝集素 II (GSL-II) 下拉分析，我们确定整合素 α6 和 β1 是 B4GALT1 的主要蛋白质底物，并且它们的 N-聚糖被 B4GALT1 修饰。此外，使用针对整合素 α6 或整合素 β1 的封闭抗体可显着逆转由 B4GALT1 敲低或敲除引起的细胞迁移和侵袭增加。这些结果表明，B4GALT1 下调会改变 N-糖基化并增强整合素 α6 和整合素 β1 的层粘连蛋白结合活性，从而促进 HCC 细胞的侵袭性。我们的研究结果为 B4GALT1 在 HCC 转移中的作用提供了新的见解，并强调靶向层粘连蛋白-整合素轴作为 B4GALT1 低表达 HCC 的潜在治疗策略。