Immunotherapy Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon, Korea.
Cancer & Developmental Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD, USA.
Oncogene. 2018 Feb 15;37(7):861-872. doi: 10.1038/onc.2017.386. Epub 2017 Oct 23.
Eph receptors and their corresponding ephrin ligands have been associated with regulating cell-cell adhesion and motility, and thus have a critical role in various biological processes including tissue morphogenesis and homeostasis, as well as pathogenesis of several diseases. Aberrant regulation of Eph/ephrin signaling pathways is implicated in tumor progression of various human cancers. Here, we show that a Rho family GTPase regulator, Rho guanine nucleotide dissociation inhibitor 1 (RhoGDI1), can interact with ephrinB1, and this interaction is enhanced upon binding the extracellular domain of the cognate EphB2 receptor. Deletion mutagenesis revealed that amino acids 327-334 of the ephrinB1 intracellular domain are critical for the interaction with RhoGDI1. Stimulation with an EphB2 extracellular domain-Fc fusion protein (EphB2-Fc) induces RhoA activation and enhances the motility as well as invasiveness of wild-type ephrinB1-expressing cells. These Eph-Fc-induced effects were markedly diminished in cells expressing the mutant ephrinB1 construct (Δ327-334) that is ineffective at interacting with RhoGDI1. Furthermore, ephrinB1 depletion by siRNA suppresses EphB2-Fc-induced RhoA activation, and reduces motility and invasiveness of the SW480 and Hs578T human cancer cell lines. Our study connects the interaction between RhoGDI1 and ephrinB1 to the promotion of cancer cell behavior associated with tumor progression. This interaction may represent a therapeutic target in cancers that express ephrinB1.
Eph 受体及其相应的 Ephrin 配体与调节细胞-细胞黏附和运动有关，因此在包括组织形态发生和动态平衡以及几种疾病的发病机制在内的各种生物学过程中具有关键作用。 Eph/ephrin 信号通路的异常调节与各种人类癌症的肿瘤进展有关。在这里，我们表明 Rho 家族 GTP 酶调节剂 Rho 鸟嘌呤核苷酸解离抑制剂 1（RhoGDI1）可以与 EphrinB1 相互作用，并且这种相互作用在结合同源 EphB2 受体的细胞外结构域时增强。 缺失突变分析显示 EphrinB1 细胞内结构域的氨基酸 327-334 对于与 RhoGDI1 的相互作用至关重要。用 EphB2 细胞外结构域-Fc 融合蛋白（EphB2-Fc）刺激会诱导 RhoA 激活，并增强野生型 EphrinB1 表达细胞的运动性和侵袭性。在表达突变的 EphrinB1 构建体（Δ327-334）的细胞中，这些 Eph-Fc 诱导的效应明显降低，该构建体与 RhoGDI1 无效相互作用。此外，通过 siRNA 耗竭 EphrinB1 会抑制 EphB2-Fc 诱导的 RhoA 激活，并减少 SW480 和 Hs578T 人癌细胞系的运动性和侵袭性。我们的研究将 RhoGDI1 与 EphrinB1 之间的相互作用与促进与肿瘤进展相关的癌细胞行为联系起来。这种相互作用可能代表表达 EphrinB1 的癌症的治疗靶标。
