To mediate selective gene delivery to hepatocytes via the asialoglycoprotein receptors (ASGP‐Rs), we designed and synthesized well‐defined and narrowly dispersed galactose‐ and glucose‐functionalized cationic polycarbonate diblock copolymers (designated as Gal‐APC and Glu‐APC, respectively) using organocatalytic ring‐opening polymerization of functionalized carbonate monomers, with a subsequent quaternization step using bis‐tertiary amines to confer quaternary and tertiary amines for DNA binding and endosomal buffering, respectively. The sugar‐functionalized diblock copolymers effectively bound and condensed DNA to form positively charged nanoparticles (<100 nm in diameter and ≈30 mV zeta‐potential) that were stable under high physiological salt conditions. In comparison to the control Glu‐APC/DNA complexes, Gal‐APC/DNA complexes mediated significantly higher gene expression in ASGP‐R positive HepG2 cells with no significant difference observed in ASGP‐R negative HeLa cells. The co‐incubation of Gal‐APC/DNA complexes with a natural ASGP‐R ligand effectively led to a decrease in gene expression, hence providing evidence for the ASGP‐R mediated endocytosis of the polyplexes. Importantly, the Gal‐APC/DNA complexes induced minimal cytotoxicities in HepG2 cells at the N/P ratios tested. Taken together, the galactose‐functionalized cationic polycarbonate diblock copolymer has potential for use as a non‐viral gene vector for the targeted delivery of therapeutic genes to hepatocytes in the treatment of liver diseases.
Abstract Lipophosphoramide-based cationic lipids are a class of synthetic vectors used for gene delivery that can be produced in multigram scale. The use of trimethylarsonium moiety as a cationic polar head was beneficial to produce efficient gene delivery vectors for in vivo applications. Moreover, this type of cationic lipid can also exhibit some bactericidal effects. 相似文献
The ester bond as a universal linker has recently been applied in gene delivery systems owing to its efficient gene release by electrostatic repulsion after its cleavage. However, the ester bond is nonlabile and is difficult to cleave in cells. This work reports a method in which a secondary amine was introduced to the β-position of the ester bond to generate a hydrogen-bond cyclization (HBC) structure that can make the ester bond hydrolysis ultrafast. A series of molecules comprising ultrasensitive esters that can be activated by H2O2 were synthesized, and it was found that those able to form an HBC structure showed complete ester hydrolysis within 5 h in both water and phosphate-buffered saline solution, which was several times faster than other methods reported. Then, a series of amphiphilic poly(amidoamine) dendrimers were constructed, comprising the ultrasensitive ester groups for gene delivery; it was found that they could effectively release genes under quite a low concentration of H2O2 (<200 μm ) and transport them into the nucleus within 2 h in Hela cells with high safety. Their gene transfection efficiencies were higher than that of PEI25k. The results demonstrated that the hydrogen-bond-induced ultrasensitive esters could be powerfully applied to construct gene delivery systems. 相似文献
NAMPT is an attractive target in cancer therapy and numerous NAMPT inhibitors have been developed. However, the clinical activities of NAMPT inhibitors have displayed disappointing results in clinical trials for their dose-limiting toxicities. In this study, reactive oxygen species (ROS)-responsive prodrugs of a NAMPT inhibitor FK866 were designed and synthesized. A short synthesis method was developed to shield the activity of FK866 through a quaternary ammonium connection. Two prodrugs, with boronic acid as a responsive group to ROS, were prepared and one of the prodrugs 122-066 also contained a fluorescence carrier. Both of the prodrugs released the active compound by the treatment of H2O2,, and the biological evaluation showed that they exhibited a higher potency in cells with high levels of ROS. Moreover, prodrug 122-066 had the ability to release FK866 and simultaneously induce the fluorescence activation under the stimulation of H2O2. This method has the potential to improve the therapeutic window of NAMPT inhibitors. 相似文献
A novel amine‐functionalized polycarbonate was synthesized and its excellent gene transfection ability in vitro is demonstrated. In the framework of adapting the cationic polycarbonate for in vivo gene delivery applications, here the design and synthesis of biodegradable block copolymers of poly(ethylene glycol) (PEG) and amine‐functionalized polycarbonate with a well‐defined molecular architecture and molecular weight is achieved by metal‐free organocatalytic ring‐opening polymerization. Copolymers in triblock cationic polycarbonate‐block‐PEG‐block‐cationic polycarbonate and diblock PEG‐block‐cationic polycarbonate configurations, in comparison with a non‐PEGylated cationic polycarbonate control, are investigated for their influence on key aspects of gene delivery. Among the polymers with similar molecular weights and N content, the triblock copolymer exhibit more favorable physicochemical (i.e., DNA binding, size, zeta‐potential, and in vitro stability) and biological (i.e., cellular uptake and luciferase reporter gene expression) properties. Importantly, the various cationic polycarbonate/DNA complexes are biocompatible, inducing minimal cytotoxicities and hemolysis. These results suggest that the triblock copolymer is a more useful architecture in future cationic polymer designs for successful systemic therapeutic applications. 相似文献
Herein we report a convenient chemical approach to reversibly modulate protein (RNase A) function and develop a protein that is responsive to reactive oxygen species (ROS) for targeted cancer therapy. The conjugation of RNase A with 4‐nitrophenyl 4‐(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl) benzyl carbonate (NBC) blocks protein lysine and temporarily deactivates the protein. However, the treatment of RNase A–NBC with hydrogen peroxide (one major intracellular ROS) efficiently cleaves the NBC conjugation and restores the RNase A activity. Thus, RNase A–NBC can be reactivated inside tumor cells by high levels of intracellular ROS, thereby restoring the cytotoxicity of RNase A for cancer therapy. Due to higher ROS levels inside tumor cells compared to healthy cells, and the resulting different levels of RNase A–NBC reactivation, RNase A–NBC shows a significant specific cytotoxicity against tumor cells. 相似文献
A series of end‐functionalized poly(trimethylene carbonate) DNA carriers, characterized by low cationic charge density and pronounced hydrophobicity, is used to study structural effects on in vitro gene delivery. As the DNA‐binding moieties are identical in all polymer structures, the differences observed between the different polymers are directly related to the functionality and length of the polymer backbone. The transfection efficiency and cytotoxicity of the polymer/DNA complexes are thus found to be dependent on a combination of polymer charge density and functionality, highlighting the importance of such structural considerations in the development of materials for efficient gene delivery.
Stimuli‐sensitive polymeric vesicles or polymersomes as self‐assembled colloidal nanocarriers have received paramount importance for their integral role as delivery system for therapeutics and biotherapeutics. This work describes spontaneous polymersome formation at pH 7, as evidenced by surface tension, steady state fluorescence, dynamic light scattering, and microscopic studies, by three hydrophilic random cationic copolymers synthesized using N ,N‐(dimethylamino)ethyl methacrylate (DMAEM) and methoxy poly(ethylene glycol) monomethacrylate in different mole ratios. The results suggest that methoxy poly(ethylene glycol) chains constitute the bilayer membrane of the polymersomes and DMAEM projects toward water constituting the positively charged surface. The polymersomes have been observed to release their encapsulated guest at acidic pH as a result of transformation into polymeric micelles. All these highly biocompatible cationic polymers show successful gene transfection ability as nonviral vector on human cell line with different potential. Thus these polymers prove their utility as a potential delivery system for hydrophilic model drug as well as genetic material.
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