Protein typing of circulating microvesicles allows real-time monitoring of glioblastoma therapy

Cancer cells shed large numbers of small, membrane-bound microvesicles (MVs) into the circulation, which have diagnostic potential but have proved difficult to analyze in a point-of-care setting. Huilin Shao and colleagues have developed a microfluidic chip with an integrated NMR detection system for the rapid profiling of circulating MVs directly from blood samples of patients with glioblastoma. The system was used to distinguish cancer cell–derived MVs from host cell–derived MVs and to measure treatment effects in vivo. Glioblastomas shed large quantities of small, membrane-bound microvesicles into the circulation. Although these hold promise as potential biomarkers of therapeutic response, their identification and quantification remain challenging. Here, we describe a highly sensitive and rapid analytical technique for profiling circulating microvesicles directly from blood samples of patients with glioblastoma. Microvesicles, introduced onto a dedicated microfluidic chip, are labeled with target-specific magnetic nanoparticles and detected by a miniaturized nuclear magnetic resonance system. Compared with current methods, this integrated system has a much higher detection sensitivity and can differentiate glioblastoma multiforme (GBM) microvesicles from nontumor host cell–derived microvesicles. We also show that circulating GBM microvesicles can be used to analyze primary tumor mutations and as a predictive metric of treatment-induced changes. This platform could provide both an early indicator of drug efficacy and a potential molecular stratifier for human clinical trials.