A radio-theranostic nanoparticle with high specific drug loading for cancer therapy and imaging

Abstract

We have developed a theranostic nanoparticle delivering the model radionuclide 177Lu based on the versatile lipid-calcium-phosphate (LCP) nanoparticle delivery platform. Characterization of 177Lu-LCP has shown that radionuclide loading can be increased by several orders of magnitude without affecting the encapsulation efficiency or the morphology of 177Lu-LCP, allowing consistency during fabrication and overcoming scale-up barriers typical of nanotherapeutics. The choice of 177Lu as a model radionuclide has allowed in vivo anticancer therapy in addition to radiographic imaging via the dual decay modes of 177Lu. Tumor accumulation of 177Lu-LCP was measured using both SPECT and Cerenkov imaging modalities in live mice, and treatment with just one dose of 177Lu-LCP showed significant in vivo tumor inhibition in two subcutaneous xenograft tumor models. Microenvironment and cytotoxicity studies suggest that 177Lu-LCP inhibits tumor growth by causing apoptotic cell death via double-stranded DNA breaks while causing a remodeling of the tumor microenvironment to a more disordered and less malignant phenotype.