Dataset Information

Rational design of Polymeric Hybrid Micelles to Overcome Lymphatic and Intracellular Delivery Barriers in Cancer Immunotherapy.

ABSTRACT: Poor distribution of antigen/adjuvant to target sites and inadequate induction of T cell responses remain major challenges in cancer immunotherapy because of the lack of appropriate delivery systems. Nanocarrier-based antigen delivery systems have emerged as an innovative strategy to improve vaccine efficacy. Here we present polymeric hybrid micelles (PHMs) as a simple and potent antigen/adjuvant co-delivery system with highly tunable properties. PHMs consist of two amphiphilic diblock copolymers, polycaprolactone-polyethylenimine (PCL-PEI) and polycaprolactone-polyethyleneglycol (PCL-PEG). PHMs with different proportions of cationic PCL-PEI were prepared and loaded with tyrosinase-related protein 2 (Trp2) peptide and adjuvant CpG oligodeoxynucleotide to generate the Trp2/PHM/CpG co-delivery system. Lymphatic and intracellular antigen delivery as a function of PCL-PEI proportion was evaluated in vitro and in vivo. PHMs containing 10% (w/w) PCL-PEI (Trp2/PHM10/CpG) showed the optimal balance of good distribution to lymph nodes, strong immunization effect after subcutaneous administration, and low toxicity to dendritic cells. In a mouse model of B16F10 melanoma, Trp2/PHM10/CpG showed significantly higher antigen-specific cytotoxic T lymphocyte activity and greater anticancer efficacy than Trp2/PHM0/CpG without PCL-PEI or a mixture of free Trp2 and CpG. These results provide new insights into how cationic segments affect the efficiency of antigen delivery by cationic nanocarriers. They also suggest that PHMs can serve as a structurally simple and highly tunable platform for co-delivery of antigen and adjuvant in cancer immunotherapy.

SUBMITTER: Li H

PROVIDER: S-EPMC5695138 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Rational design of Polymeric Hybrid Micelles to Overcome Lymphatic and Intracellular Delivery Barriers in Cancer Immunotherapy.

Li Hanmei H Li Yanping Y Wang Xue X Hou Yingying Y Hong Xiaoyu X Gong Tao T Zhang Zhirong Z Sun Xun X

Theranostics 20170926 18

Poor distribution of antigen/adjuvant to target sites and inadequate induction of T cell responses remain major challenges in cancer immunotherapy because of the lack of appropriate delivery systems. Nanocarrier-based antigen delivery systems have emerged as an innovative strategy to improve vaccine efficacy. Here we present polymeric hybrid micelles (PHMs) as a simple and potent antigen/adjuvant co-delivery system with highly tunable properties. PHMs consist of two amphiphilic diblock copolymer ...[more]

PMID: 29158834

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Project description:Peptides derived from the third Bcl-2 homology domain (BH3) renormalize apoptotic signaling by antagonizing prosurvival Bcl-2 family members. These potential peptide drugs exhibit therapeutic activities but are limited by barriers including short circulation half-lives and poor penetration into cells. A diblock polymeric micelle carrier for the BIM BH3 peptide was recently described that demonstrated antitumor activity in a B-cell lymphoma xenograft model [Berguig et al., Mol. Ther. 2015, 23, 907-917]. However, the disulfide linkage used to conjugate the BIM peptide was shown to have nonoptimal blood stability. Here we describe a peptide macromonomer composed of BIM capped with a four amino acid cathepsin B substrate (FKFL) that possesses high blood stability and is cleaved to release the drug inside of target cells. Employing RAFT polymerization, the peptide macromonomer was directly integrated into a multifunctional diblock copolymer tailored for peptide delivery. The first polymer block was made as a macro-chain transfer agent (CTA) and composed of a pH-responsive endosomolytic formulation of N,N-diethylaminoethyl methacrylate (DEAEMA) and butyl methacrylate (BMA). The second polymer block was a copolymer of the peptide and polyethylene glycol methacrylate (PEGMA). PEGMA monomers of two sizes were investigated (300 Da and 950 Da). Protein gel analysis, high performance liquid chromatography, and coupled mass spectrometry (MS) showed that incubation with cathepsin B specifically cleaved the FKFL linker and released active BIM peptide with PEGMA300 but not with PEGMA950. MALDI-TOF MS showed that incubation of the peptide monomers alone in human serum resulted in partial cleavage at the FKFL linker after 12 h. However, formulation of the peptides into polymers protected against serum-mediated peptide degradation. Dynamic light scattering (DLS) demonstrated pH-dependent micelle disassembly (25 nm polymer micelles at pH 7.4 versus 6 nm unimers at pH 6.6), and a red blood cell lysis assay showed a corresponding increase in membrane destabilizing activity (<1% lysis at pH 7.4 versus 95% lysis at pH 6.6). The full carrier-drug system successfully induced apoptosis in SKOV3 ovarian cancer cells in a dose-dependent manner, in comparison to a control polymer containing a scrambled BIM peptide sequence. Mechanistic analysis verified target-dependent activation of caspase 3/7 activity (8.1-fold increase), and positive annexin V staining (72% increase). The increased blood stability of this enzyme-cleavable peptide polymer design, together with the direct polymerization approach that eliminated postsynthetic conjugation steps, suggests that this new carrier design could provide important benefits for intracellular peptide drug delivery.

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Dataset Information

Rational design of Polymeric Hybrid Micelles to Overcome Lymphatic and Intracellular Delivery Barriers in Cancer Immunotherapy.

Publications

Rational design of Polymeric Hybrid Micelles to Overcome Lymphatic and Intracellular Delivery Barriers in Cancer Immunotherapy.

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