School of Biosciences, The University of Melbourne, Melbourne, Victoria, 3010, Australia.
The University of Queensland, Queensland Brain Institute, Brisbane, Queensland, 4072, Australia.
Sci Rep. 2019 Mar 11;9(1):4110. doi: 10.1038/s41598-019-40886-y.
Neogenin1 (NEO1) is a receptor of the Deleted in Colorectal Carcinoma (DCC)/Frazzled/UNC-40 family, which regulates axon guidance but can also stabilize epithelial adherens junctions. NEO1 and DCC are also tumor suppressors that can inhibit metastasis by acting as dependence receptors. Given the role of NEO1 in maintaining adherens junctions we tested whether loss of NEO1 also promoted metastasis via an epithelial mesenchymal transition (EMT). Loss of NEO1 disrupted zonula adherens but tight junctions were unaffected. Neo1-depleted epithelial cells exhibited a more migratory morphology, had reduced F-actin rich stress-fibres and more basal lamellipodia. Microtubule density was decreased while microtubule outgrowth was faster. Live imaging showed that Neo1-depleted epithelial islands had increased lateral movement. Western blots and immunostaining revealed increased expression of mesenchymal markers such as Fibronectin and MMP1. Furthermore, RNA-seq analysis showed a striking decrease in expression of genes associated with oxidative phosphorylation, and increased expression of genes associated with EMT, locomotion, and wound-healing. In summary, loss of NEO1 in intestinal epithelial cells produces a partial EMT response, based on gene expression, cellular morphology and behaviour and cytoskeletal distribution. These results suggest that loss of NEO1 in carcinomas may contribute to metastasis by promoting a partial EMT and increased motility.
神经钙黏蛋白 1（NEO1）是Deleted in Colorectal Carcinoma（DCC）/Frazzled/UNC-40 家族的受体，可调节轴突导向，但也能稳定上皮细胞黏着连接。NEO1 和 DCC 也是肿瘤抑制因子，可通过作为依赖性受体抑制转移。鉴于 NEO1 在维持黏着连接中的作用，我们测试了 NEO1 的缺失是否也通过上皮间质转化（EMT）促进转移。NEO1 的缺失破坏了黏着连接，但紧密连接不受影响。缺乏 NEO1 的上皮细胞表现出更具迁移性的形态，具有更少的富含 F-肌动蛋白的应力纤维和更多的基底膜足状伪足。微管密度降低，而微管生长更快。实时成像显示，缺乏 NEO1 的上皮细胞小岛侧向运动增加。Western blot 和免疫染色显示，间充质标志物如纤维连接蛋白和 MMP1 的表达增加。此外，RNA-seq 分析显示与氧化磷酸化相关的基因表达显著下降，与 EMT、运动和伤口愈合相关的基因表达增加。总之，肠上皮细胞中 NEO1 的缺失会产生部分 EMT 反应，这基于基因表达、细胞形态和行为以及细胞骨架分布。这些结果表明，癌细胞中 NEO1 的缺失可能通过促进部分 EMT 和增加迁移性来促进转移。
