腹膜转移经常伴随转移性和/或复发性胃癌，由于缺乏有效的治疗而导致预后不良。因此，迫切需要加强我们对驱动腹膜转移的机制和分子的理解。在之前的一项研究中，半乳糖凝集素 4 抑制可阻止小鼠模型中的腹膜转移。这项研究检查了具有不同致瘤潜力的细胞中细胞表面蛋白和鞘糖脂 (GSL) 的聚糖谱，以了解 galectin-4 介导的调节（特别是糖基化）背后的复杂机制。详细的质谱分析表明，半乳糖凝集素 4 敲除细胞表现出带有 β1,3 连接半乳糖的乳系列 GSL 表达增加，而新乳系列 GSL 没有显着变化。我们进行了实时聚合酶链式反应 (PCR) 分析，以确定合成增加水平的 GSL 的候选糖基转移酶。随后，我们引入候选B3GALT5基因并选择高表达水平的克隆。 B3GALT5 基因表达克隆显示出与敲除细胞类似的 GSL 聚糖谱，并且在小鼠模型中显着降低了致瘤能力。这些克隆表现出增殖能力减弱，并且半乳糖凝集素 4 和激活的 AKT 表达降低。此外，在表达 B3GALT5 的细胞中，galectin-4 与 flotillin-2（筏标记物）的共定位减少，表明 GSL 参与了 galectin-4 定位到脂筏的过程。 D-threo-1-苯基-2-decanoylamino-3-morpholino-1-propanol（一种 GSL 合酶抑制剂）也影响筏中的 galectin-4 定位，表明 GSL 微结构域的参与。我们发现 B3GALT5 通过抑制细胞增殖并通过尚未阐明的机制调节脂筏和半乳糖凝集素 4，在调节恶性胃癌细胞的腹膜转移中发挥着至关重要的作用。© 作者 2024。由牛津大学出版按。版权所有。如需权限，请发送电子邮件至：journals.permissions@oup.com。

Peritoneal metastasis frequently accompanies metastatic and/or recurrent gastric cancer, leading to a poor prognosis owing to a lack of effective treatment. Hence, there is a pressing need to enhance our understanding of the mechanisms and molecules driving peritoneal metastasis. In a previous study, galectin-4 inhibition impeded peritoneal metastasis in a murine model. This study examined the glycan profiles of cell surface proteins and glycosphingolipids (GSLs) in cells with varying tumorigenic potentials to understand the intricate mechanisms underlying galectin-4-mediated regulation, particularly glycosylation. Detailed mass spectrometry analysis showed that galectin-4 knockout cells exhibit increased expression of lacto-series GSLs with β1,3-linked galactose while showing no significant alterations in neolacto-series GSLs. We conducted real-time polymerase chain reaction (PCR) analysis to identify candidate glycosyltransferases that synthesize increased levels of GSLs. Subsequently, we introduced the candidate B3GALT5 gene and selected the clones with high expression levels. B3GALT5 gene-expressing clones showed GSL glycan profiles like those of knockout cells and significantly reduced tumorigenic ability in mouse models. These clones exhibited diminished proliferative capacity and showed reduced expression of galectin-4 and activated AKT. Moreover, co-localization of galectin-4 with flotillin-2 (a raft marker) decreased in B3GALT5-expressing cells, implicating GSLs in galectin-4 localization to lipid rafts. D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (a GSL synthase inhibitor) also affected galectin-4 localization in rafts, suggesting the involvement of GSL microdomains. We discovered that B3GALT5 plays a crucial role in regulating peritoneal metastasis of malignant gastric cancer cells by suppressing cell proliferation and modulating lipid rafts and galectin-4 via mechanisms that are yet to be elucidated.© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.