Antibody fragment (Fab′)-installed polyion complex (PIC) micelles were constructed to improve targetability of small interfering RNA (siRNA) delivery to pancreatic cancer cells. To this end, we synthesized a block copolymer of azide-functionalized poly(ethylene glycol) and poly(l-lysine) and prepared PIC micelles with siRNA. Then, a dibenzylcyclooctyne (DBCO)-modified antihuman tissue factor (TF) Fab′ was conjugated to azido groups on the micellar surface. A fluorescence correlation spectroscopic analysis revealed that 1, 2, or 3 molecule(s) of Fab′(s) were installed onto one micellar nanoparticle according to the feeding ratio of Fab′ (or DBCO) to micelle (or azide). The resulting micelles exhibited ∼40 nm in hydrodynamic diameter, similar to that of the parent micelles before Fab′ conjugation. Flow cytometric analysis showed that three molecules of Fab′-installed PIC micelles (3(Fab′)-micelles) had the highest binding affinity to cultured pancreatic cancer BxPC3 cells, which are known to overexpress TF on their surface. The 3(Fab′)-micelles also exhibited the most efficient gene silencing activity against polo-like kinase 1 mRNA in the cultured cancer cells. Furthermore, the 3(Fab′)-micelles exhibited high penetrability and the highest cellular internalization amounts in BxPC3 spheroids compared with one or two molecule(s) of Fab′-installed PIC micelles. These results demonstrate the potential of anti-TF Fab′-installed PIC micelles for active targeting of stroma-rich pancreatic tumors.
Bibliographical noteFunding Information:
This work was financially supported by Center of Innovation (COI) program from Japan Science and Technology Agency (JST) and Grants-in-Aid for Scientific Research (KAKENHI Grant Numbers 25000006 for KK and 17H02098 for KM) from Ministry of Education Culture, Sports, Science and Technology (MEXT). This work was also partially supported by the Project for Cancer Research and Therapeutics Evolution (P-CREATE) and Basic Science and Platform Technology Program for Innovative Biological Medicine from Japan Agency for Medical Research and Development (AMED) and the Mochida Memorial Foundation for Medical and Pharmaceutical Research. H.S.M. was supported by Global Innovative Research Center (GiRC) project (2012K1A1A2A01055811) of National Research Foundation of Korea and Overseas Researcher under Postdoctoral Fellowship of Japan Society for the Promotion of Science (JSPS).
© 2018 American Chemical Society.
ASJC Scopus subject areas
- Polymers and Plastics
- Materials Chemistry