Improvement in the colloidal stability of protein kinase-responsive polyplexes by PEG modification.

We have reported a disease-cell specific gene expression system that is responsive to intracellular signaling proteins (e.g., protein kinases and proteases) hyperactivated in diseased cells. For this system, cationic peptide-grafted polymers were synthesized for polyplex formation with genes. Here, we modified poly(ethylene glycol) (PEG) to a protein kinase A (PKA)-responsive polymer to improve polyplex stability. PEG modification neutralized the surface charge of the polyplex and successfully increased polyplex stability at physiological conditions. However, PEG modification (PEG contents, 0.6 and 3.3 mol %) showed almost negligible effects on the reactivity of grafted peptides to PKA and the promotion of gene expression responding to PKA activity. Excessive modification of PEG (PEG contents, 6.8 mol %) inhibited polyplex formation. These results indicate that moderate modification of PEG to the enzyme-responsive polymer improves polyplex stability without inhibiting the reaction with enzymes.

[1]  T. Niidome,et al.  Transgene regulation system responding to Rho associated coiled-coil kinase (ROCK) activation. , 2011, Journal of controlled release : official journal of the Controlled Release Society.

[2]  T. Niidome,et al.  Tumor therapy by gene regulation system responding to cellular signal. , 2010, Journal of controlled release : official journal of the Controlled Release Society.

[3]  K. Kataoka,et al.  Quantized folding of plasmid DNA condensed with block catiomer into characteristic rod structures promoting transgene efficacy. , 2010, Journal of the American Chemical Society.

[4]  Takeshi Mori,et al.  Controlled release of PEG chain from gold nanorods: targeted delivery to tumor. , 2010, Bioorganic & medicinal chemistry.

[5]  T. Niidome,et al.  Inflammatory cell‐specific transgene expression system responding to Iκ‐B kinase beta activation , 2009, The journal of gene medicine.

[6]  Peter Wipf,et al.  Nanoparticles in cellular drug delivery. , 2009, Bioorganic & medicinal chemistry.

[7]  Vladimir P Torchilin,et al.  Self-assembling micelle-like nanoparticles based on phospholipid-polyethyleneimine conjugates for systemic gene delivery. , 2009, Journal of controlled release : official journal of the Controlled Release Society.

[8]  Tae-Jin Lee,et al.  Heparin-conjugated polyethylenimine for gene delivery. , 2008, Journal of controlled release : official journal of the Controlled Release Society.

[9]  T. Niidome,et al.  Design of polymeric carriers for cancer-specific gene targeting: utilization of abnormal protein kinase Calpha activation in cancer cells. , 2008, Journal of the American Chemical Society.

[10]  H. Merkle,et al.  PEGylation as a tool for the biomedical engineering of surface modified microparticles. , 2008, Journal of pharmaceutical sciences.

[11]  Yuichi Yamasaki,et al.  PEG-detachable polyplex micelles based on disulfide-linked block catiomers as bioresponsive nonviral gene vectors. , 2008, Journal of the American Chemical Society.

[12]  S. Ganta,et al.  A review of stimuli-responsive nanocarriers for drug and gene delivery. , 2008, Journal of controlled release : official journal of the Controlled Release Society.

[13]  M. Textor,et al.  Characterization of PLL-g-PEG-DNA nanoparticles for the delivery of therapeutic DNA. , 2008, Bioconjugate chemistry.

[14]  Tomoko Ito,et al.  Efficient in vivo gene transfection by stable DNA/PEI complexes coated by hyaluronic acid , 2008 .

[15]  N. Nishiyama,et al.  Gene delivery with biocompatible cationic polymer: pharmacogenomic analysis on cell bioactivity. , 2007, Biomaterials.

[16]  T. Niidome,et al.  An intracellular kinase signal-responsive gene carrier for disordered cell-specific gene therapy. , 2006, Journal of controlled release : official journal of the Controlled Release Society.

[17]  J. Kopeček,et al.  PEGylation of poly(ethylene imine) affects stability of complexes with plasmid DNA under in vivo conditions in a dose-dependent manner after intravenous injection into mice. , 2005, Bioconjugate chemistry.

[18]  P. Cohen.  The role of protein phosphorylation in human health and disease. The Sir Hans Krebs Medal Lecture. , 2001, European journal of biochemistry.

[19]  H. Maeda.  The enhanced permeability and retention (EPR) effect in tumor vasculature: the key role of tumor-selective macromolecular drug targeting. , 2001, Advances in enzyme regulation.

[20]  C. C. Carlson,et al.  Protein kinase A regulatory subunits in colon cancer. , 1999, Neoplasia.

[21]  C. Pouton,et al.  Polycation-DNA complexes for gene delivery: a comparison of the biopharmaceutical properties of cationic polypeptides and cationic lipids. , 1998, Journal of controlled release : official journal of the Controlled Release Society.

[22]  W. Miller,et al.  Elevation of protein kinase A and protein kinase C activities in malignant as compared with normal human breast tissue. , 1996, European journal of cancer.

[23]  Y. Nishizuka.  The role of protein kinase C in cell surface signal transduction and tumour promotion , 1984, Nature.

[24]  R. Niles,et al.  Retinoic acid increases cyclic AMP-dependent protein kinase activity in murine melanoma cells. , 1980, The Journal of biological chemistry.

[25]  W. Radchatawedchakoon,et al.  Solid phase synthesis of novel asymmetric hydrophilic head cholesterol-based cationic lipids with potential DNA delivery. , 2010, Bioorganic & medicinal chemistry.

[26]  N. Ho.  Professor William I. Higuchi: teacher and scientist. , 2008, Journal of pharmaceutical sciences.

[27]  Lei Yu,et al.  An acid-labile block copolymer of PDMAEMA and PEG as potential carrier for intelligent gene delivery systems. , 2008, Biomacromolecules.

[28]  S. Merajver,et al.  Suppression of tumor recurrence and metastasis by a combination of the PHSCN sequence and the antiangiogenic compound tetrathiomolybdate in prostate carcinoma. , 2002, Neoplasia.