Leukemia-Specific siRNA Delivery by Immunonanoplexes Consisting of Anti-JL1 Minibody Conjugated to Oligo-9 Arg-Peptides

Abstract

Targeted mRNA degradation by short interfering RNAs (siRNAs) offers a great potential to treat cancers. siRNA therapeutics for leukemias are, however, hindered by poor intracellular uptake, limited blood stability and non-specific delivery. To solve these problems, we developed an anti-JL1 immunonanoplex (antibody-coupled nano-complex) for siRNA delivery using anti-JL1 minibody (leu-kemia cell-specific minibody) conjugated to oligo-9-Arg peptide (9R) for effective siRNA delivery to leukemic cells. The anti-JL1 immunonanoplexes were able to deliver siRNA specifically to leukemic cells (CEM and Jurkat), but not to control cancer cells (H9). According to FACS and confocal microscopic analysis, siRNAs delivered by im-munonanoplex particles were rapidly taken up by the JL1-positive cancer cells in 2 h. Furthermore, we showed that the anti-JL1 immunonanoplexes were effectively targeted to JL1-positive cells (CEM) inoculated in the mouse bone marrow. These results suggest that the anti-JL1 immu-nonanoplex is a powerful siRNA delivery system for hu-man leukemia therapies.