A Combined Approach Employing Chlorotoxin-Nanovectors and Low Dose Radiation To Reach Infiltrating Tumor Niches in Glioblastoma

Glioblastoma multiforme (GBM) is the most aggressive form of glioma, with life expectancy of around 2 years after diagnosis, due to recidivism and to the blood-brain barrier (BBB) limiting the amount of drugs which reach the residual malignant cells, thus contributing to the failure of chemotherapies. To bypass the obstacles imposed by the BBB, we investigated the use of nanotechnologies combined with radiotherapy, as a potential therapeutic strategy for GBM. We used poly­(lactic-<i>co</i>-glycolic acid) (PLGA) nanoparticles (PNP) conjugated to chlorotoxin (CTX), a peptide reported to bind selectively to glioma cells. Silver nanoparticles were entrapped inside the functionalized nanoparticles (Ag-PNP-CTX), to allow detection and quantification of the cellular uptake by confocal microscopy, both <i>in vitro</i> and <i>in vivo</i>. <i>In vitro</i> experiments performed with different human glioblastoma cell lines showed higher cytoplasmic uptake of Ag-PNP-CTX, with respect to nonfunctionalized nanoparticles. <i>In vivo</i> experiments showed that Ag-NP-CTX efficiently targets the tumor, but are scarcely effective in crossing the blood brain barrier in the healthy brain, where dispersed metastatic cells are present. We show here that single whole brain X-ray irradiation, performed 20 h before nanoparticle injection, enhances the expression of the CTX targets, MMP-2 and ClC-3, and, through BBB permeabilization, potently increases the amount of internalized Ag-PNP-CTX even in dispersed cells, and generated an efficient antitumor synergistic effect able to inhibit <i>in vivo</i> tumor growth. Notably, the application of Ag-PNP-CTX to irradiated tumor cells decreases the extracellular activity of MMP-2. By targeting dispersed GBM cells and reducing MMP-2 activity, the combined use of CTX-nanovectors with radiotherapy may represent a promising therapeutic approach toward GBM

Aptamer Functionalization of Nanosystems for Glioblastoma Targeting through the Blood–Brain Barrier

Polymeric nanoparticles (PNPs) may efficiently deliver in vivo therapeutics to tumors when conjugated to specific targeting agents. Gint4.T aptamer specifically recognizes platelet-derived growth factor receptor β and can cross the blood–brain barrier (BBB). We synthesized Gint4.T-conjugated PNPs able of high uptake into U87MG glioblastoma (GBM) cells and with astonishing EC₅₀ value (38 pM) when loaded with a PI3K-mTOR inhibitor. We also demonstrated in vivo BBB passage and tumor accumulation in a GBM orthotopic model

EGFR-Targeted Magnetic Nanovectors Recognize, <i>in Vivo</i>, Head and Neck Squamous Cells Carcinoma-Derived Tumors

Head and neck squamous cell carcinomas (HNSCC) are a diverse group of tumors with high morbidity and mortality that have remained mostly unchanged over the past decades. The epidermal growth factor receptor (EGFR) is often overexpressed and activated in these tumors and strongly contributes to their pathogenesis. Still, EGFR-targeted therapies such as monoclonal antibodies and kinase inhibitors have demonstrated only limited improvements in the clinical outcome of this disease. Here, we take advantage of the extraordinary affinity of EGF for its cognate receptor to specifically target magnetite-containing nanoparticles to HNSCC cells and mediate, <i>in vitro</i>, their cellular upload. On the basis of this, we show efficient accumulation, <i>in vivo</i>, of such nanoparticles in subcutaneous xenograft tumor tissues in sufficient amounts to be able to mediate visualization by magnetic resonance imaging. Overall, our EGF-coated nanosystem may warrant, in the near future, novel and very efficient theranostic approaches to HNSCC