Abstract
Several RNA-targeted therapeutics, including antisense oligonucleotides (ONs), small interfering RNAs, and miRNAs, constitute immunostimulatory CpG motifs as an integral part of their design. The limited success with free antisense ONs in hematologic malignancies in recent clinical trials has been attributed to the CpG motif-mediated, TLR-induced prosurvival effects and inefficient target modulation in desired cells. In an attempt to diminish their off-target prosurvival and proinflammatory effects and specific delivery, as a proof of principle, in the present study, we developed an Ab-targeted liposomal delivery strategy using a clinically relevant CD20 Ab (rituximab)-conjugated lipopolyplex nanoparticle (RIT-INP)- and Bcl-2-targeted antisense G3139 as archetypical antisense therapeutics. The adverse immunostimulatory responses were abrogated by selective B cell-targeted delivery and early endosomal compartmentalization of G3139-encapsulated RIT-INPs, resulting in reduced NF-κB activation, robust Bcl-2 down-regulation, and enhanced sensitivity to fludarabine-induced cytotoxicity. Furthermore, significant in vivo therapeutic efficacy was noted after RIT-INP-G3139 administration in a disseminated xenograft leukemia model. The results of the present study demonstrate that CD20-targeted delivery overcomes the immunostimulatory properties of CpG-containing ON therapeutics and improves efficient gene silencing and in vivo therapeutic efficacy for B-cell malignancies. The broader implications of similar approaches in overcoming immunostimulatory properties of RNA-directed therapeutics in hematologic malignancies are also discussed.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Adjuvants, Immunologic / antagonists & inhibitors
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Animals
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Antibodies, Monoclonal, Murine-Derived / administration & dosage*
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Antibodies, Monoclonal, Murine-Derived / therapeutic use
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Antimetabolites, Antineoplastic / pharmacokinetics
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Antimetabolites, Antineoplastic / therapeutic use*
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Cell Line, Tumor / transplantation
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CpG Islands
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Drug Resistance, Neoplasm / drug effects
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Gene Expression Regulation, Leukemic / drug effects
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Gene Silencing
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Genes, bcl-2 / drug effects
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Humans
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Leukemia, Lymphocytic, Chronic, B-Cell / therapy*
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Liposomes
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Mice
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Mice, Inbred NOD
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Mice, SCID
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Molecular Targeted Therapy*
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Nanoparticles / administration & dosage
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Nanoparticles / therapeutic use*
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Neoplasm Proteins / biosynthesis
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Neoplasm Proteins / genetics
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Oligonucleotides, Antisense / pharmacokinetics
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Oligonucleotides, Antisense / therapeutic use*
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Proto-Oncogene Proteins c-bcl-2 / biosynthesis
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RNA, Small Interfering / pharmacology
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Rituximab
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Thionucleotides / pharmacokinetics
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Thionucleotides / therapeutic use*
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Toll-Like Receptor 9 / antagonists & inhibitors
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Toll-Like Receptor 9 / genetics
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Toll-Like Receptor 9 / immunology
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Vidarabine / analogs & derivatives*
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Vidarabine / pharmacokinetics
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Vidarabine / therapeutic use
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Xenograft Model Antitumor Assays
Substances
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Adjuvants, Immunologic
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Antibodies, Monoclonal, Murine-Derived
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Antimetabolites, Antineoplastic
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Liposomes
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Neoplasm Proteins
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Oligonucleotides, Antisense
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Proto-Oncogene Proteins c-bcl-2
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RNA, Small Interfering
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Thionucleotides
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Tlr9 protein, mouse
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Toll-Like Receptor 9
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Rituximab
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oblimersen
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Vidarabine
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fludarabine