Portable Monitoring System for Assessing Therapeutic Efficacy in HER2-Overexpressing Breast Cancer: One-Step Simultaneous Detection of Cancer-Derived Exosomal Proteins and mRNA in Urine

Abstract

Point-of-care (POC) monitoring of patient condition is crucial for effective cancer treatment and prognosis. This can be achieved non-invasively by analyzing exosomes in body fluids. However, the heterogeneity of exosomes and non-standardized quantification methods may interfere with clearly determining the patient's condition. Therefore, there is a need for technology that can precisely analyze both tumor-derived exosomes and normal exosomes. Herein, this study presents the exosome multiple-separation for simultaneous detection (EXO-MUSSID) platform, which simultaneously isolates different exosomes based on their magnetization properties and monitors therapeutic efficacy of drugs. Using immunoaffinity magnetophoresis technology, HER2-overexpressing and normal exosomes are collected separately, enabling real-time monitoring of HER2 (also known as ERBB2) expression by analyzing the mRNA of each exosome based on a catalytic hairpin assembly (CHA) reaction. A portable fluorescence reader customized for the EXO-MUSSID platform is developed for POC monitoring of HER2-overexpressing breast cancer (HER2+ BC). The performance of the EXO-MUSSID platform is validated using urine samples from HER2+ BC mouse models, confirming the progression of HER2+ BC and the changes in HER2 expression due to trastuzumab treatment. It is expected to serve as a valuable tool for exosome-based liquid biopsy in disease monitoring.