Anti-CD22 Antibody Targeting of PH-Responsive Micelles Enhances Small Interfering RNA Delivery and Gene Silencing in Lymphoma Cells


The application of small interfering RNA (siRNA) for cancer treatment is a promising strategy currently being explored in early phase clinical trials. However, efficient systemic delivery limits clinical implementation. We developed and tested a novel delivery system comprised of (i) an internalizing streptavidin-conjugated monoclonal antibody (mAb-SA) directed against CD22 and (ii) a biotinylated diblock copolymer containing both a positively charged siRNA condensing block and a pH-responsive block to facilitate endosome release. The modular design of the carrier facilitates the exchange of different targeting moieties and siRNAs to permit its usage in a variety of tumor types. The polymer was synthesized using the reversible addition fragmentation chain transfer (RAFT) technique and formed micelles capable of binding siRNA and mAb-SA. A hemolysis assay confirmed the predicted membrane destabilizing activity of the polymer under acidic conditions typical of the endosomal compartment. Enhanced siRNA uptake was demonstrated in DoHH2 lymphoma and transduced HeLa-R cells expressing CD22 but not in CD22 negative HeLa-R cells. Gene knockdown was significantly improved with CD22-targeted vs. nontargeted polymeric micelles. Treatment of DoHH2 cells with CD22-targeted polymeric micelles containing 15nmol/l siRNA produced 70% reduction of gene expression. This CD22-targeted polymer carrier may be useful for siRNA delivery to lymphoma cells.


Materials Science and Engineering

Keywords and Phrases

copolymer; monoclonal antibody; monoclonal antibody CD22; small interfering RNA; unclassified drug, article; controlled study; endosome; erythrocyte; gene delivery system; gene expression; gene silencing; genetic transfection; HeLa cell; hemolysis; human; human cell; internalization; light scattering; lymphoma cell; micelle; pH; synthesis

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Article - Journal

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© 2011 Nature Publishing Group, All rights reserved.

Publication Date

01 Aug 2011