Site-specific antibody-polymer conjugates for siRNA delivery.
We describe here the development of site-specific antibody-polymer conjugates (APCs) for the selective delivery of small interference RNAs (siRNAs) to target cells. APCs were synthesized in good yields by conjugating an aminooxy-derivatized cationic block copolymer to an anti-HER2 Fab or full-length IgG by means of genetically encoded p-acetyl phenylalanine (pAcF). The APCs all showed binding affinity comparable to that of HER2 as their native counterparts and no significant cellular cytotoxicity. Mutant S202-pAcF Fab and Q389-pAcF IgG polymer conjugates specifically delivered siRNAs to HER2(+) cells and mediated potent gene silencing at both the mRNA and protein levels. However, a mutant A121-pAcF IgG polymer conjugate, despite its high binding affinity to HER2 antigen, did not induce a significant RNA interference response in HER2(+) cells, presumably due to steric interference with antigen binding and internalization. These results highlight the importance of conjugation site on the activity of antibody-polymer-based therapeutics and suggest that such chemically defined APCs may afford a useful targeted delivery platform for siRNAs or other nucleic acid-based therapies.
Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States.
Hua
H
Lu
Danling
D
Wang
Stephanie
S
Kazane
Tsotne
T
Javahishvili
Feng
F
Tian
Frank
F
Song
Aaron
A
Sellers
Barney
B
Barnett
Peter G
PG
Schultz
D000906:Antibodies / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D016503:Drug Delivery Systems; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D018796:Immunoconjugates / Q000494:pharmacology*; D018613:Microscopy, Confocal; D011108:Polymers / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000494:pharmacology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000737:chemistry; D000068878:Trastuzumab
D000906:Antibodies; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D018796:Immunoconjugates; D011108:Polymers; D034741:RNA, Small Interfering; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human