Targeted Doxorubicin-loaded Bacterially Derived Nano-cells for the Treatment of Neuroblastoma.

Advanced stage neuroblastoma is an aggressive disease with limited treatment options for patients with drug-resistant tumors. Targeted delivery of chemotherapy for pediatric cancers offers promise to improve treatment efficacy and reduce toxicity associated with systemic chemotherapy. The EnGeneIC Dream Vector (EDV (TM)) is a nanocell, which can package chemotherapeutic drugs and target tumors via attachment of bispecific proteins to the surface of the nanocell. Phase I trials in adults with refractory tumors have shown an acceptable safety profile. Herein we investigated the activity of EGFR-targeted and doxorubicin-loaded EDV (TM) ((EDV)-E-EGFR (TM)(Dox)) for the treatment of neuroblastoma. Two independent neuroblastoma cell lines with variable expression of EGFR protein [SK-N-BE(2), high; SH-SY-5Y, low] were used. (EDV)-E-EGFR (TM)(Dox) induced apoptosis in these cells compared to control, doxorubicin, or non-doxorubicin loaded (EDV)-E-EGFR (TM). In three-dimensional tumor spheroids, imaging and fluorescence life-time microscopy revealed that (EDV)-E-EGFR (TM)(Dox) had a marked enhancement of doxorubicin penetration compared to doxorubicin alone, and improved penetration compared to non-EGFRtargeted EDV (TM)(Dox), with enhanced spheroid penetration leading to increased apoptosis. In two independent orthotopic human neuroblastoma xenograft models, short-term studies (28 days) of tumor-bearing mice led to a significant decrease in tumor size in (EDV)-E-EGFR (TM)(Dox)-treated animals compared to control, doxorubicin, or non-EGFR EDV (TM)(Dox). There was increased TUNEL staining of tumors at day 28 compared to control, doxorubicin, or non-EGFR EDV (TM)(Dox). Moreover, overall survival was increased in neuroblastoma mice treated with (EDV)-E-EGFR (TM)(Dox) (P < 0007) compared to control. Drug-loaded bispecific-antibody targeted EDVs (TM) offer a highly promising approach for the treatment of aggressive pediatric malignancies such as neuroblastoma. (C) 2018 AACR.