RESUMO
Na+/H+ exchanger regulatory factor 1 (NHERF1) has been reported to interact with post-synaptic density protein/Drosophila disc large tumour suppressor/zonula occludens 1 protein (PDZ) binding proteins by its two PDZ domains. These associations have effects on cellular signal transductions. NHERF1 has also been indicated as a cancer-related gene in several solid tumour types. We identified a novel mutation (A190D), of the PDZ2 domain of NHERF1 in breast cancer tissues. NHERF1 A190D mutation abolished NHERF1 modulation of proliferation and migration. In this study, we found that NHERF1 A190D mutation increased nuclear localisation of the protein compared to wild-type NHERF1. It has been reported that YES-associated protein (YAP) interacts with NHERF1. Here we found that NHERF1 A190D mutation increased the binding affinity between NHERF1 and YAP, which inhibited the phosphorylation of YAP. These data suggest that wild-type NHERF1 acts as a tumour suppressor, while NHERF1 A190D mutation abolishes the tumour-suppressive effect in cancer cells, due to A190D mutation-mediated nuclear NHERF1 translocation and induction of YAP phosphorylation.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Mutação , Fosfoproteínas/genética , Trocadores de Sódio-Hidrogênio/genética , Proteínas Supressoras de Tumor/genética , Transporte Ativo do Núcleo Celular , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Células COS , Movimento Celular , Proliferação de Células , Chlorocebus aethiops , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Células HEK293 , Humanos , Células MCF-7 , Invasividade Neoplásica , Fenótipo , Fosfoproteínas/metabolismo , Fosforilação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Interferência de RNA , Transdução de Sinais , Trocadores de Sódio-Hidrogênio/metabolismo , Fatores de Tempo , Fatores de Transcrição , Transfecção , Proteínas Supressoras de Tumor/metabolismo , Proteínas de Sinalização YAPRESUMO
BACKGROUND: Na(+)/H(+) exchanger regulatory factor 1 (NHERF1) has been reported to interact with many cancer-related proteins. We recently identified a novel NHERF1 mutation (E43G) in breast tumours. MATERIALS AND METHODS: The candidates of NHERF1 mutation were identified in breast cancer tissues by polymerase chain reaction and DNA sequencing. Wild-type NHERF1 and E43G mutation were expressed in NHERF1-knockdown cells (MCF7ΔNHERF1) and low-NHERF1-expressing cells (SKMES-1). The effects of mutated NHERF1 on cell functions were examined using in vitro methods. Glutathione S-transferase pull-down assays and western blotting were performed to study the effects of NHERF1 mutation on its interaction with cancer-related proteins. RESULTS: Compared to wild-type NHERF1, expression of the mutated NHERF1 failed to suppress malignant traits in cancer cells, attenuated interaction of NHERF1 protein with epidermal growth factor receptor (EGFR), and inactivated its inhibition of EGF-induced Akt and extracellular regulated protein kinases (ERK) activation. CONCLUSION: The results show the causal role of NHERF1 in the regulation of the EGFR pathway and the progression of breast cancer.