Precise delivery of a multifunctional nanosystem for MRI-guided cancer therapy and monitoring of tumor response by functional diffusion-weighted MRI

The rational design of imaging-guided, highly efficient tumor-targeted delivery systems is of profound importance for improving cancer therapeutic efficacy. Herein, a cRGD peptide-functionalized poly(lactic-co-glycolic acid) (cRGD-PLGA) block copolymer was synthesized to encapsulate doxorubicin (DOX) and superparamagnetic iron oxide (SPIO) for magnetic resonance imaging (MRI)-guided cancer therapy. The micelles exhibited excellent pH-responsive drug release properties under physiological conditions and integrin-targeting ability. In an in vivo study, cRGD-PLGA-SPIO@DOX micelles exhibited improved antitumor effects and reduced toxicity compared with DOX drug treatment. The micelles can act as a theranostic agent for real-time therapeutic monitoring. Importantly, diffusion-weighted MRI was utilized to predict and monitor the cancer treatment response in nanomedicine therapy. Furthermore, the micelles also exhibited a preferable pharmacodynamic profile and significantly reduced side effects compared with DOX. In summary, we performed a proof-of-concept study demonstrating that cRGD-PLGA-SPIO@DOX micelles are a high-efficiency nanoparticulate drug-delivery platform for MR imaging-guided cancer theranostics. Taken together, this study provides a new strategy for combining functional diffusion-weighted MRI techniques and functionalized nanomicelles for precise cancer theranostics.