Ultrasmall Renally Clearable Silica Nanoparticles Target Prostate Cancer

Although important advances have been achieved in the development of radiolabeled prostate-specific membrane antigen (PSMA)-targeting ligand constructs for both diagnosis and therapy of prostate cancer (PCa) over the past decade, challenges related to off-target effects and limited treatment responses persist. In this study, which builds upon the successful clinical translation of a series of ultrasmall, dye-encapsulating core-shell silica nanoparticles, or Cornell Prime Dots (C' dots), for cancer management, we sought to address these limitations by designing a dual-modality, PSMA-targeting platform that evades undesirable accumulations in the salivary glands, kidneys, and reticuloendothelial system, while exhibiting bulk renal clearance. This versatile PCa-targeted particle imaging probe offers significant clinical potential to improve future theranostic applications in a variety of patient care settings.

Melanocortin-1 Receptor-Targeting Ultrasmall Silica Nanoparticles for Dual-Modality Human Melanoma Imaging

The poor prognosis associated with malignant melanoma has not changed substantially over the past 30 years. Targeted molecular therapies, such as immunotherapy, have shown promise but suffer from resistance and off-target toxicities, underscoring the need for alternative therapeutic strategies that can be used in combination with existing protocols. Moreover, peptides targeting melanoma-specific markers, like the melanocortin-1 receptor (MC1-R), for imaging and therapy exhibit high renal uptake that limits clinical translation. In the current study, the application of ultrasmall fluorescent (Cy5) silica nanoparticles (C' dots), conjugated with MC1-R targeting alpha melanocyte stimulating hormone (αMSH) peptides on the polyethylene glycol (PEG) coated surface, is examined for melanoma-selective imaging. αMSH peptide sequences, evaluated for conjugation to the PEG-Cy5-C' dot nanoparticles, bound to MC1-R with high affinity and targeted melanoma in syngenetic and xenografted melanoma mouse models. Results demonstrated a 10-fold improvement in MC1-R affinity over the native peptide alone following surface attachment of the optimal αMSH peptide. Systematic in vivo studies further demonstrated favorable in vivo renal clearance kinetics as well as receptor-mediated tumor cell internalization of as-developed radiolabeled particle tracers in B16F10 melanoma bearing mice. These findings highlight the ability of αMSH-PEG-Cy5-C' dots to overcome previous hurdles that prevented clinical translation of peptide and antibody-based melanoma probes and reveal the potential of αMSH-PEG-Cy5-C' dots for melanoma-selective imaging, image-guided surgery, and therapeutic applications.