Nanoparticles for ex vivo siRNA delivery to dendritic cells for cancer vaccines: programmed endosomal escape and dissociation.
We previously developed octaarginine (R8)-modified lipid envelope-type nanoparticles for siRNA delivery (R8-MEND). Herein, we report on their ex vivo siRNA delivery to primary mouse bone marrow-derived dendritic cells (BMDCs) for potential use as a cancer vaccine. Quantitative imaging analysis of the intracellular trafficking of siRNA revealed that the dissociation process, as well as the rate of endosomal escape limits the siRNA efficiency of the prototype R8-MEND, prepared by the hydration method (R8-MEND(hydo)). Successful endosomal escape was achieved by using a pH-dependent fusogenic peptide (GALA) modified on a lipid mixture that was optimized for endosomal fusion. Furthermore, a modified protocol for the preparation of nanoparticles, mixing the siRNA/STR-R8 complex and small unilamellar vesicles (R8/GALA-MEND(SUV)), results in a more homogenous, smaller particle size, and results in a more efficient intracellular dissociation. Gene knockdown of the suppressor of cytokine signaling 1 (SOCS1), a negative-feedback regulator of the immune response in BMDCs resulted in an enhanced phosphorylation of STAT1, and the production of proinflammatory cytokines. Moreover, SOCS1-silenced BMDCs were more potent in suppressing tumor growth. Collectively, these results show that siRNA loaded in R8/GALA-MEND(SUV) efficiently suppresses endogenous gene expression and consequently enhances dendritic cell-based vaccine potency in vivo.
Akita
Hidetaka
H
Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, Hokkaido 060-0812, Japan.
Kogure
Kentaro
K
Moriguchi
Rumiko
R
Nakamura
Yoshio
Y
Higashi
Tomoko
T
Nakamura
Takashi
T
Serada
Satoshi
S
Fujimoto
Minoru
M
Naka
Tetsuji
T
Futaki
Shiroh
S
Harashima
Hideyoshi
H
D000818:Animals; D019496:Cancer Vaccines / Q000008:administration & dosage*; D003713:Dendritic Cells / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D005260:Female; D055785:Gene Knockdown Techniques; D015316:Genetic Therapy / Q000379:methods; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry*; D009369:Neoplasms / Q000628:therapy*; D009842:Oligopeptides / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000627:therapeutic use; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics
D019496:Cancer Vaccines; D009842:Oligopeptides; D034741:RNA, Small Interfering; D050826:Suppressor of Cytokine Signaling Proteins; C448619:octaarginine