A Novel Fluorescence Imaging Of HER2 Dimerization On Cancer Cells By Using A Co-localization Triggered DNA Nanoassembly

Aberrant dimerization of human epidermal growth factor receptor 2(HER2),which plays crucial role in driving the carcinogenesis of the breast cell,is potential and significant biomarker for guiding personalized targeted HER2 therapy of breast cancer.However,its clinical application was limited due to the lack of simple,practical and sensitive detection system for the analysis of HER2 dimers.Therefore,the clinical application of HER2 dimer as a novel breast cancer marker is in urgent need of a convenient,sensitive and practical method for in-situ detection of protein dimer.Based on the specificity of aptamer proximity hybridization and the high sensitivity of hairpin-free nonlinear HCR,a colocalization-triggered DNA nanoassembly(CtDNA)strategy was developed for amplified imaging of HER2 dimerization.Firstly,the mechanism of step-by-step hairpin-free nonlinear HCR for DNA dendritic nanoassembly was studied by native polyacrylamide gel electrophoresis,atomic force microscopy and fluorometry.The results revealed a high specificity,sensitivity,andexcellent control ability of the DNA dendritic nanoassembly.Then a new method based on CtDNA strategy for detection of HER2/HER2 homodimers and HER2/HER3 heterodimers on breast cancer cell surface was explored.Finally,it was then extended to in-situ image and quantitative analysis of HER2 homologous dimers in clinical formalin-fixed paraffin-embedded breast cancer tissue specimens.The results show that CtDNA strategy is a simple,practical and sensitive new technique for cell surface protein dimer imaging,which can be used for in-situ detection of HER2 dimer in breast cancer.