Cathepsin B-sensitive polymers for compartment-specific degradation and nucleic acid release

• Published in: Journal of controlled release 2012-02, Vol.157 (3), p.445-454
• Main Authors: Chu, David S.H., Johnson, Russell N., Pun, Suzie H.
• Format: Article
• Language: English
• Subjects: amino acids; Animals; Biological and medical sciences; Cathepsin B; Cathepsin B - metabolism; Cell Survival - drug effects; composite polymers; DNA; DNA - administration & dosage; DNA - chemistry; General pharmacology; HeLa Cells; Humans; Medical sciences; Mice; Nanoparticles - administration & dosage; Nanoparticles - chemistry; NIH 3T3 Cells; Non-viral gene delivery; Oligopeptides - administration & dosage; Oligopeptides - chemistry; peptides; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; polymerization; Polymers - administration & dosage; Polymers - chemistry; RAFT polymerization; toxicity; transfection; Transfection - methods
• ISSN: 0168-3659; 1873-4995
• DOI: 10.1016/j.jconrel.2011.10.016

Degradable cationic polymers are desirable for in vivo nucleic acid delivery because they offer significantly decreased toxicity over non-degradable counterparts. Peptide linkers provide chemical stability and high specificity for particular endopeptidases but have not been extensively studied for nucleic acid delivery applications. In this work, enzymatically degradable peptide-HPMA copolymers were synthesized by RAFT polymerization of HPMA with methacrylamido-terminated peptide macromonomers, resulting in polymers with low polydispersity and near quantitative incorporation of peptides. Three peptide-HPMA copolymers were evaluated: (i) pHCathK10, containing peptides composed of the linker phe-lys-phe-leu (FKFL), a substrate of the endosomal/lysosomal endopeptidase cathepsin B, connected to oligo-(l)-lysine for nucleic acid binding, (ii) pHCath(d)K10, containing the FKFL linker with oligo-(d)-lysine, and (iii) pH(d)Cath(d)K10, containing all (d) amino acids. Cathepsin B degraded copolymers pHCathK10 and pHCath(d)K10 within 1h while no degradation of pH(d)Cath(d)K10 was observed. Polyplexes formed with pHCathK10 copolymers show DNA release by 4h of treatment with cathepsin B; comparatively, polyplexes formed with pHCath(d)K10 and pH(d)Cath(d)K10 show no DNA release within 8h. Transfection efficiency in HeLa and NIH/3T3 cells were comparable between the copolymers but pHCathK10 was less toxic. This work demonstrates the successful application of peptide linkers for degradable cationic polymers and DNA release. [Display omitted]