Development of a long-acting, protein-loaded, redox-active, injectable gel formed by a polyion complex for local protein therapeutics.
Although cancer immunotherapies are attracting much attention, it is difficult to develop bioactive proteins owing to the severe systemic toxicity. To overcome the issue, we designed new local protein delivery system by using a protein-loaded, redox-active, injectable gel (RIG), which is formed by a polyion complex (PIC) comprising three components, viz., cationic polyamine-poly(ethylene glycol)-polyamine triblock copolymer possessing ROS-scavenging moieties as side chains; anionic poly(acrylic acid); and a protein. The mixture formed the protein-loaded PIC flower micelles at room temperature, which immediately converted to a gel with high mechanical strength upon exposure to physiological conditions. Because the protein electrostatically interacts with the PIC gel network, RIG provided a sustained release of the protein without a significant initial burst, regardless of the types of proteins in vitro, and much longer retention of the protein at the local injection site in mice than that of the naked protein. Subcutaneous injections of IL-12@RIG in the vicinity of tumor tissue showed remarkable tumor growth inhibition in tumor-bearing mice, compared to that observed with injection of IL-12 alone, suppressing adverse events caused by IL-12-induced ROS. Our results indicate that RIG has potential as a platform technology for an injectable sustained-release carrier for proteins.
['Ishii|Shiro|S|', 'Kaneko|Junya|J|', 'Nagasaki|Yukio|Y|']
D000818:Animals D000970:Antineoplastic Agents D045744:Cell Line, Tumor D016503:Drug Delivery Systems D019793:Fluorescein D005782:Gels D007167:Immunotherapy D007267:Injections D018664:Interleukin-12 D007477:Ions D008297:Male D008807:Mice, Inbred BALB C D008819:Mice, Nude D008823:Micelles D009589:Nitrogen Oxides D010084:Oxidation-Reduction D010316:Particle Size D044367:Phase Transition D011108:Polymers D011506:Proteins D012212:Rheology D013696:Temperature D044366:Transition Temperature D014783:Viscosity
Cancer immunotherapy Local protein delivery Injectable hydrogel Polyion complex flower micelle Reactive oxygen species