Clinically diagnosing low-grade gliomas and microscopic metastatic tumors in the spinal cord using magnetic resonance imaging (MRI) is challenging, as the blood-brain barrier (BBB) almost completely excludes the MRI contrast agent gadopentetate dimeglumine, GdDTPA (Magnevist), from the brain. The development of a more efficient, safe, and broad-spectrum glioma diagnosis and treatment would therefore have a great clinical value. Based on the high expression levels of both transferrin receptor 1 (TfR1) and low-density lipoprotein receptor-related protein 1 (LRP1) in BBB-related cells and glioma cells, we designed a novel protein nanoparticle, ferritin-HREV107-Angiopep-2 (Fn-Rev-Ang). We found that Fn-Rev-Ang rapidly crossed the BBB in mice and had drug-loading properties. Moreover, the brain MRI signal intensity ratio associated with Fn-Rev-Ang-GdDTPA was higher than that associated with Fn-GdDTPA alone. Importantly, gliomas with diameters below 1 mm and microscopic metastatic tumors in the spinal cord were successfully detected in mice by MRI with Fn-Rev-Ang-GdDTPA, which is not possible using the current clinical MRI technology. In addition, Fn-Rev-Ang-loaded doxorubicin had a strong inhibitory effect on mouse brain gliomas and their metastasis, which significantly prolonged the animal survival time. Thus, our newly constructed Fn-Rev-Ang nanodelivery carrier may help expand the use of MRI to the early diagnosis and treatment of microscopic tumors, thereby offering a possible basis for improving the survival rate of patients with gliomas and microscopic spinal metastatic tumors.
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