糖基化深刻影响卵巢癌（OC）腹膜播散转移过程中癌细胞与微环境基质细胞之间的相互作用，这是癌症相关死亡的主要原因。尽管特征性癌症糖复合物被广泛用作癌症诊断的生物标志物，但由于分析具有巨大结构和功能异质性的聚糖链的技术限制，我们对癌症糖组的了解仍然相当碎片化。鉴于失调的癌症糖组是由改变的糖基化机制定义的，在这里，我们对涉及 OC 传播关键调节因子糖基化的 498 个基因进行了系统的功能丧失筛查。我们鉴定出神经氨酸酶 4 (NEU4)，一种能够从糖复合物中水解末端唾液酸的酶，作为 OC 糖组的重要腹膜传播促进修饰剂。在患有高级浆液性 OC (HGSOC) 的人类患者中，与原发性肿瘤细胞相比，在播散性 OC 细胞中检测到 NEU4 增加，这与较差的生存率显着相关。在人类 NEU4 的三种剪接生成亚型中，我们发现只有质膜定位的 NEU4 亚型 2 (NEU4-iso2) 和细胞内亚型 3 通过增强细胞运动和上皮间质转化来促进 OC 的腹膜传播。我们还鉴定了 NEU4-iso2 调节的细胞表面糖蛋白组，并发现 NEU4-iso2 使上皮生长因子受体 (EGFR) 去唾液酸化，特别是在 N196 残基处，导致 EGFR 及其下游促肿瘤信号级联的过度激活。我们的结果提供了关于 OC 糖组在 OC 进展过程中如何失调的新见解，并揭示了 EGFR 上的一个功能重要的糖位点，因为它在癌症中异常激活。© 2024。作者，获得 Springer Nature Limited 的独家许可。

Glycosylation profoundly influences the interactions between cancer cells and microenvironmental stromal cells during the peritoneal disseminated metastasis of ovarian carcinoma (OC), which is the major cause of cancer-related death. Although the characteristic cancer glycoconjugates are widely used as biomarkers for cancer diagnosis, our knowledge about cancer glycome remains quite fragmented due to the technique limitations in analyzing glycan chains with tremendous structural and functional heterogeneity. Given the dysregulated cancer glycome is defined by the altered glycosylation machinery, here we performed a systematic loss-of-function screen on 498 genes involved in glycosylation for key regulators of OC dissemination. We identified neuraminidase 4 (NEU4), an enzyme capable of hydrolyzing terminal sialic acid from glycoconjugates, as a vital peritoneal dissemination-promoting modifier of OC glycome. In human patients with high-grade serous OC (HGSOC), increased NEU4 was detected in the disseminated OC cells when compared with that in the primary tumor cells, which significantly correlated with the worse survival. Among three alternative splice-generated isoforms of human NEU4, we revealed that only the plasma membrane-localized NEU4 isoform 2 (NEU4-iso2) and intracellular isoform 3 promoted the peritoneal dissemination of OC by enhancing the cell motility and epithelial-mesenchymal transition. We also identified NEU4-iso2-regulated cell surface glycoproteome and found that NEU4-iso2 desialylated the epithelial growth factor receptor (EGFR), in particular at N196 residue, for the hyperactivation of EGFR and its downstream tumor-promoting signaling cascades. Our results provide new insights into how the OC glycome is dysregulated during OC progression and reveal a functionally important glycosite on EGFR for its abnormal activation in cancer.© 2024. The Author(s), under exclusive licence to Springer Nature Limited.