Background: The appearance of hybrid epithelial-mesenchymal (E/M) cells expressing E-cadherin is favourable for the establishment of pro-invasive function. However, the molecular mechanism and potential roles of E-cadherin in cancer cell invasion stay unexplored. Methods: We used models of E/M hybrid cell lines, tissues sections and patient-derived xenografts from a multi-center clinical trial. E-cadherin involvement in invadopodia formation was assessed using a gelatin-FITC degradation assay. Mechanistic studies were performed by using proteomic analysis, siRNA strategy and proximity ligation assay. Results: We showed that E-cadherin is a critical component of invadopodia. This unexpected localization results from a synergistic trafficking of E-cadherin and MT1-MMP through Rab vesicle-dependent pathway. Modulation of E-cadherin expression or activation impacted invadopodia formation. Moreover, colocalization of E-cadherin and Actin in "ring structures" as precursor of invadopodia reveals that E-cadherin is required for invadopodia structuration. Conclusion: E-cadherin, initially localized in the adherens junctions could be recycled to nascent invadopodia where it will interact with several components such as Arp2/3, Cortactin or MT1-MMP. The trans-adhesive properties of E-cadherin are therefore essential for structuring invadopodia.

中文翻译：

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E-钙粘蛋白是胰腺癌侵袭伪足的结构成分

背景：表达E-钙粘蛋白的混合上皮间充质（E/M）细胞的出现有利于促侵袭功能的建立。然而，E-钙粘蛋白在癌细胞侵袭中的分子机制和潜在作用仍有待探索。方法：我们使用来自多中心临床试验的 E/M 杂交细胞系模型、组织切片和患者来源的异种移植物。使用明胶-FITC 降解测定评估 E-钙粘蛋白参与侵袭伪足形成。通过使用蛋白质组分析、siRNA 策略和邻近连接测定进行机理研究。结果：我们发现 E-钙粘蛋白是侵袭伪足的重要组成部分。这种意想不到的定位是 E-钙粘蛋白和 MT1-MMP 通过 Rab 囊泡依赖性途径协同运输的结果。E-钙粘蛋白表达或激活的调节影响侵袭伪足的形成。此外，E-钙粘蛋白和肌动蛋白在作为侵袭伪足前体的“环结构”中的共定位表明，E-钙粘蛋白是侵袭伪足结构所必需的。结论：最初位于粘附连接处的 E-钙粘蛋白可以再循环到新生的侵袭伪足，在那里它将与 Arp2/3、Cortactin 或 MT1-MMP 等多种成分相互作用。因此，E-钙粘蛋白的反式粘附特性对于构建侵袭伪足至关重要。