Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, Brazil.
J Struct Biol. 2018 Apr;202(1):61-69. doi: 10.1016/j.jsb.2017.12.007. Epub 2017 Dec 19.
Nuclear Epidermal Growth Factor Receptor (EGFR) has been associated with worse prognosis and treatment resistance for several cancer types. After Epidermal Growth Factor (EGF) binding, the ligand-receptor complex can translocate to the nucleus where it functions in oncological processes. By three-dimensional quantification analysis of super-resolution microscopy images, we verified the translocation kinetics of fluorescent conjugated EGF to the nucleus in two mesenchymal cell types: human adipose tissue-derived stem cells (hASC) and SK-HEP-1 tumor cells. The number of EGF clusters in the nucleus does not change after 10 min of stimulation with EGF in both cells. The total volume occupied by EGF clusters in the nucleus of hASC also does not change after 10 min of stimulation with EGF. However, the total volume of EGF clusters increases only after 20 min in SK-HEP-1 cells nuclei. In these cells the nuclear volume occupied by EGF is 3.2 times higher than in hASC after 20 min of stimulation, indicating that translocation kinetics of EGF differs between these two cell types. After stimulation, EGF clusters assemble in larger clusters in the cell nucleus in both cell types, which suggests specific sub-nuclear localizations of the receptor. Super-resolution microscopy images show that EGF clusters are widespread in the nucleoplasm, and can be localized in nuclear envelope invaginations, and in the nucleoli. The quantitative study of EGF-EGFR complex translocation to the nucleus may help to unravel its roles in health and pathological conditions, such as cancer.
核表皮生长因子受体（EGFR）与多种癌症类型的预后不良和治疗耐药有关。表皮生长因子（EGF）结合后，配体-受体复合物可易位到细胞核，在那里发挥致癌作用。通过超分辨率显微镜图像的三维定量分析，我们验证了两种间充质细胞类型：人脂肪组织来源干细胞（hASC）和 SK-HEP-1 肿瘤细胞中荧光共轭 EGF 向核内易位的动力学。在这两种细胞中，用 EGF 刺激 10 分钟后，核内 EGF 簇的数量没有变化。用 EGF 刺激 10 分钟后，hASC 细胞核内 EGF 簇的总体积也没有变化。然而，只有在 SK-HEP-1 细胞核中刺激 20 分钟后，EGF 簇的总体积才会增加。在这些细胞中，EGF 占据的核体积在刺激 20 分钟后是 hASC 的 3.2 倍，这表明 EGF 在这两种细胞类型中的易位动力学不同。刺激后，EGF 簇在两种细胞类型的细胞核中组装成更大的簇，这表明受体有特定的亚核定位。超分辨率显微镜图像显示，EGF 簇广泛分布在核质中，并且可以定位于核膜内陷和核仁中。EGF-EGFR 复合物向核内易位的定量研究可能有助于揭示其在健康和病理条件下（如癌症）的作用。
