Kollara Alexandra, Burt Brian D, Ringuette Maurice J, Brown Theodore J
Lunenfeld-Tanenbaum Research Institute, Sinai Health Systems, Toronto, ON, Canada; Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON, Canada.
Lunenfeld-Tanenbaum Research Institute, Sinai Health Systems, Toronto, ON, Canada; Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.
Cell Signal. 2023 Jun;106:110634. doi: 10.1016/j.cellsig.2023.110634. Epub 2023 Feb 23.
Upregulation of ERBB2 and activating mutations in downstream KRAS/BRAF and PIK3CA are found in several ovarian cancer histotypes. ERBB2 enhances signaling by the ERBB family of EGF receptors, and contains docking positions for proteins that transduce signaling through multiple pathways. We identified the adaptor protein ventricular zone-expressed pleckstrin homology domain-containing protein 1 (VEPH1) as a potential interacting partner of ERBB2 in a screen of proteins co-immunoprecipitated with VEPH1. In this study, we confirm a VEPH1 - ERBB2 interaction by co-immunoprecipitation and biotin proximity labelling and show that VEPH1 interacts with the juxtamembrane-kinase domain of ERBB2. In SKOV3 ovarian cancer cells, which bear a PIK3CA mutation and ERBB2 overexpression, ectopic VEPH1 expression enhanced EGF activation of ERK1/2, and mTORC2 activation of AKT. In contrast, in ES2 ovarian cancer cells, which bear a BRAF mutation with VEPH1 amplification but low ERBB2 expression, loss of VEPH1 expression enabled further activation of ERK1/2 by EGF and enhanced EGF activation of AKT. VEPH1 expression in SKOV3 cells enhanced EGF-induced cell migration consistent with increased Snail2 and decreased E-cadherin levels. In comparison, loss of VEPH1 expression in ES2 cells led to decreased cell motility independent of EGF treatment despite higher levels of N-cadherin and Snail2. Importantly, we found that loss of VEPH1 expression rendered ES2 cells less sensitive to BRAF and MEK inhibition. This study extends the range of adaptor function of VEPH1 to ERBB2, and indicates VEPH1 has differential effects on EGF signaling in ovarian cancer cells that may be influenced by driver gene mutations.
在几种卵巢癌组织类型中发现了ERBB2的上调以及下游KRAS/BRAF和PIK3CA的激活突变。ERBB2增强了表皮生长因子（EGF）受体ERBB家族的信号传导，并包含通过多种途径转导信号的蛋白质的对接位点。在与含pleckstrin同源结构域的脑室区表达蛋白1（VEPH1）共免疫沉淀的蛋白质筛选中，我们鉴定出衔接蛋白VEPH1是ERBB2的潜在相互作用伴侣。在本研究中，我们通过共免疫沉淀和生物素邻近标记证实了VEPH1与ERBB2的相互作用，并表明VEPH1与ERBB2的近膜激酶结构域相互作用。在携带PIK3CA突变和ERBB2过表达的SKOV3卵巢癌细胞中，异位VEPH1表达增强了ERK1/2的EGF激活以及AKT的mTORC2激活。相反，在携带BRAF突变、VEPH1扩增但ERBB2表达低的ES2卵巢癌细胞中，VEPH1表达缺失使EGF能进一步激活ERK1/2并增强AKT的EGF激活。SKOV3细胞中VEPH1的表达增强了EGF诱导的细胞迁移，这与Snail2增加和E-钙黏蛋白水平降低一致。相比之下，ES2细胞中VEPH1表达缺失导致细胞运动性降低，且与EGF处理无关，尽管N-钙黏蛋白和Snail2水平较高。重要的是，我们发现VEPH1表达缺失使ES2细胞对BRAF和MEK抑制的敏感性降低。本研究将VEPH1的衔接蛋白功能范围扩展至ERBB2，并表明VEPH1对卵巢癌细胞中EGF信号传导具有不同影响，这可能受驱动基因突变影响。
