Rituximab-Conjugated DART Nanoformulation for CD20-Targeted Drug Delivery in Non-Hodgkin Lymphoma

To develop rituximab (RTX)-conjugated decreased nonspecific adhesivity receptor-targeted (DART) nanoparticles for CD20-targeted paclitaxel (PTX) delivery in non-Hodgkin lymphoma (NHL) and evaluate their targeting, therapeutic activity, formulation stability, and immune-associated cellular responses.

PTX-loaded PLGA-PEG nanoparticles were conjugated with RTX (RTX-DART/PTX) or control IgG (IgG-DART/PTX). Physicochemical properties and colloidal and frozen-storage stability were characterized. CD20-dependent cellular association and intracellular localization were evaluated in Raji lymphoma cells using flow cytometry, competitive blocking, and confocal microscopy. Cytotoxicity was assessed following short-term treatment and media replacement. Calreticulin (CRT) surface exposure and macrophage polarization-associated markers were evaluated in vitro. Anti-tumor efficacy was assessed in a systemic luciferase-expressing Raji xenograft model.

RTX-DART/PTX exhibited a size near 100 nm, low polydispersity, near-neutral surface charge, and 7-8% PTX loading. DART nanoparticles maintained their colloidal properties in serum incubation for up to 72 hours, while frozen storage at -20°C in 10% sucrose for 3 weeks preserved physicochemical properties and biological activity. RTX-DART showed greater CD20-dependent cellular association and intracellular localization than IgG-DART and free RTX blocking reduced nanoparticle association. Under short-exposure conditions, RTX-DART/PTX produced greater cytotoxicity than free PTX and IgG-DART/PTX. RTX-DART/PTX also enhanced CRT surface exposure, while PTX-containing treatments altered macrophage polarization-associated markers and IGF1 secretion in vitro. In vivo, RTX-DART/PTX reduced systemic tumor bioluminescence and improved survival relative to PBS and IgG-DART/PTX.

These findings support RTX-DART/PTX as a proof-of-concept CD20-targeted nanomedicine strategy for systemic NHL. Further validation in additional lymphoma models, immunocompetent or humanized systems, and pharmacokinetic and biodistribution studies is required.