A nano polymer conjugate for dual drugs sequential release and combined treatment of colon cancer and thrombotic complications.

Thrombotic complications turn into the second leading cause of death in colon cancer patients due to the hypercoagulable state caused by malignancy. Therefore, it is necessary to treat colon cancer and its thrombosis complications simultaneously. Herein, a nano polymer conjugate based on disulfide cross-linked low-generation peptide dendrimers was developed to treat colon cancer and its thrombotic complications. First, two-generation polyglutamic acid dendrimer was bonded to nattokinase (NK) and then cross-linkers containing disulfide linkages were used to obtain polymer conjugates (NK-G2)n. Then doxorubicin (Dox) was encapsulated. The system can release drugs sequentially due to the dissociation of the polymer conjugates. In vitro thrombolytic experiments exhibited a significant thrombolysis ability of (NK-G2)n. The toxicity and cellular uptake tests on HCT116 cells showed that Dox loaded polymer conjugates had good endocytosis ability and anti-cancer effect. Therefore, this drug delivery system will be a promising strategy to the combined treatment of colon cancer and thrombotic complications.

A polysaccharide-based micelle-hydrogel synergistic therapy system for diabetes and vascular diabetes complications treatment.

Various glucose-sensitive drug delivery platforms have been developed recently to treat diabetes. However, there is much less work has been reported on treatment of diabetes and vascular diabetes complications simultaneously. In this work, a novel polysaccharide-based micelle-hydrogel synergistic therapy system was fabricated to address this limitation. Zwitterionic dialdehyde starch-based micelles (SB-DAS-VPBA) were synthesized via single electron transfer-living radical polymerization (SET-LRP). Hydrophilic segment sulfobetaine (SB) and hydrophobic segment 4­vinylphenylboronic acid (VPBA) were grafted to the dialdehyde starch (DAS) backbones. Then, chitosan/dialdehyde starch derivatives (CS/SB-DAS-VPBA) micelle-hydrogel was synthesized by Schiff-base bonds. Insulin and nattokinase were loaded to obtain the micelle-hydrogel synergistic therapy system. In vitro drug delivery and blood clots dissolution behaviors were determined. Results suggest that the micelle-hydrogel synergistic therapy system not only possesses glucose-responsive insulin delivery property, but also provides good thrombolytic capacity. Thus, this micelle-hydrogel synergistic therapy system can be used as a platform for diabetes and vascular diabetes complications treatment.

Multiarm-polyethylene glycol-polyglutamic acid peptide dendrimer: Design, synthesis, and dissolving thrombus.

Thrombotic events affect many individuals in a number of ways, all of which can cause significant morbidity and mortality. Nattokinase (NK), as a novel thrombolytic drug, has been used for thrombolytic therapy. It not only possesses plasminogen activator activity, but also directly digests fibrin through limited proteolysis. However, it may undergo inactivation and denaturation in the harsh external environment. In this study, a multiarm-polyethylene glycol-polyglutamic acid peptide dendrimer was fabricated and used as a carrier for NK protection and delivery. Different arm numbers of polyethylene glycol-polyglutamic acid peptide dendrimers (x-PEG(G3 )x , x = 2, 4, 6, 8) were designed, prepared, and characterized by 1 H NMR and FTIR. Then, x-PEG(G3 )x were loaded with NK to form nanocomposites. Their size and morphology were determined by dynamic light scattering and transmission electron microscopy. Enzyme activity was evaluated via UV-Vis absorbance spectra, fluorescence spectra, circular dichroism spectra, and zeta potential measurements. The study reveals that the obtained x-PEG(G3 )x /NK nanocomposites possess high enzyme activity. In addition, the nanocomposites show increased viability of rat macrophage cells, and excellent thrombolysis ability in vitro and in vivo. This work establishes a multiarm-polyethylene glycol-polyglutamic acid peptide dendrimer with potential application in NK carrier and thrombolytic therapy. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1687-1696, 2018.

High encapsulation and localized delivery of curcumin from an injectable hydrogel.

Most chemotherapy currently available for cancer treatment has limited potential to successful clinical cancer therapy, mainly due to low encapsulating capacity of drugs and unavailable pharmacologically beneficial concentrations at the tumor site. Herein, a novel yet simple strategy is developed to enhance drug encapsulating capacity and localized drug concentration using an injectable hydrogel based on thiolated chitosan (TCS) and poly(ethylene glycol) diacrylate (PEGDA). Almost 100% of encapsulating capacity is achieved when anti-cancer drug curcumin is encapsulated in the system. The interaction of curcumin with PEGDA is determined by fluorescence spectroscopy and the binding constant is calculated, followed by a simulation by a docking study using AutoDock. To improve the anti-tumor activity and achieve effective local concentrations, lysozyme is introduced into the system. Sustained curcumin release in a controlled lysozyme-responsive behaviour is observed, which enables the drug concentration to reach the therapeutic threshold promptly. The system displays efficient intracellular curcumin release to promote cancer cells apoptosis in vitro. In addition, the system effectively delays the tumor growth and reduces adverse effects in tumor-bearing nude mice. The strategy of localized, high encapsulation of drug by using an injectable hydrogel would be particularly beneficial with many insoluble anti-cancer drugs.

Synthesis of PEGylated polyglutamic acid peptide dendrimer and its application in dissolving thrombus.

Nattokinase (NK) has been used as a new generation thrombolytic drug, due to its high safety, low cost and low side effects. However, it is sensitive to external environment and may lose the enzyme activity easily. Peptide dendrimer possesses functional groups on its surface, adjustable sizes, biodegradability, biocompatibility, and low toxicity, which could be used as ideal carrier for drug protection and delivery. Demonstrated for the first time in this paper, a PEGylated dendrimer (Gn-PEG-Gn) composed of polyglutamic acid is designed and synthesized as delivery platform of NK for thrombus treatment. A panel of PEGylated dendrimers with three different generations of 2, 3, 4 was prepared to investigate the effect of dendrimer architecture on the properties and therapeutic efficacy of the resultant NK-loaded delivery systems in terms of the morphology, dimension and enzyme activity. The results demonstrated that the NK-loaded G3-PEG-G3 (G3-PEG-G3/NK ratio of 6/1), of all the formulations, displayed the optimal enzyme activity for dissolving thrombus in vitro, thus offering great potential for the treatment of thrombus.

Physicochemical characterization of amphiphilic nanoparticles based on the novel starch-deoxycholic acid conjugates and self-aggregates.

Novel amphiphilic polymers (starch-deoxycholic acid, St-DCA) were firstly synthesized on the basis of starch (St) as a hydrophilic segment and deoxycholic acid (DCA) as a hydrophobic segment. Hydrophobically modified starch contained 5.4-8.9 deoxycholic acid groups per 100 anhydroglucose units of starch. Self-aggregates of St-DCA conjugates were formed in the PBS media. Physicochemical characterizations of St-DCA conjugates were investigated. The mean sizes of self-aggregates decreased with the degree of substitution (DS) and pH increasing. Zeta potential indicated that nanoparticles were covered with negatively charged starch shells from -5.4 to -23 mV. TEM images demonstrated that nanoparticles were of spherical shape. The critical aggregation concentrations (cac) were dependent on the DS and pH in the range of 0.0185-0.0441 mg/mL. Thus, the study suggested that self-aggregated nanoparticles of St-DCA conjugates could have good pH-responsive and potential application in pharmaceutical and biomedical fields as the delivery of anti-tumor drugs.

Facile preparation of pH-sensitive micelles self-assembled from amphiphilic chondroitin sulfate-histamine conjugate for triggered intracellular drug release.

Stimuli-responsive materials, enabling drugs to be released in the acidic tumor and intracellular microenvironments, draw an increasing attention in chemotherapy. Here novel pH-sensitive biodegradable micelles are fabricated using a one-step, one-medium process without organic solvent for efficient loading and rapid intracellular release of hydrophobic cargos. The amphiphilic chondroitin sulfate-histamine conjugate (CS-his) were successfully synthesized and assembled into nanoparticles in aqueous medium with desirable size (133 nm) and low critical micelle concentration (CMC) (0.05 mg/L). Owning to the pH-sensitive structure of imidazole, the nanoparticles show pH-responsive behavior upon reducing the pH value of surrounding media, accompany with formation of large aggregates and increase of ζ potential. When the nanoparticles were utilized to deliver the model drug DOX, they exhibited a specific on-off switch drug release behavior, triggering DOX release in acidic surroundings (intracellular endosomes) and sealing DOX in neutral surroundings (blood circulation or extracellular matrix). CCK-8 assays and confocal laser scanning microscopy (CLSM) against HepG2 cells indicated that the nanoparticles themselves had no associated cytotoxicity, while drug-loaded nanoparticles possessed high cytotoxicity to model cells and presented high efficiency of cellular uptake. These flexible micelles with an on-off switched drug release may offer a promising pattern to accurately deliver a wide variety of hydrophobic payloads to tumor cells for cancer therapy.

A Taiwanese Propolis Derivative Induces Apoptosis through Inducing Endoplasmic Reticular Stress and Activating Transcription Factor-3 in Human Hepatoma Cells.

Activating transcription factor-(ATF-) 3, a stress-inducible transcription factor, is rapidly upregulated under various stress conditions and plays an important role in inducing cancer cell apoptosis. NBM-TP-007-GS-002 (GS-002) is a Taiwanese propolin G (PPG) derivative. In this study, we examined the antitumor effects of GS-002 in human hepatoma Hep3B and HepG2 cells in vitro. First, we found that GS-002 significantly inhibited cell proliferation and induced cell apoptosis in dose-dependent manners. Several main apoptotic indicators were found in GS-002-treated cells, such as the cleaved forms of caspase-3, caspase-9, and poly(ADP-ribose) polymerase (PARP). GS-002 also induced endoplasmic reticular (ER) stress as evidenced by increases in ER stress-responsive proteins including glucose-regulated protein 78 (GRP78), growth arrest- and DNA damage-inducible gene 153 (GADD153), phosphorylated eukaryotic initiation factor 2 α (eIF2 α ), phosphorylated protein endoplasmic-reticular-resident kinase (PERK), and ATF-3. The induction of ATF-3 expression was mediated by mitogen-activated protein kinase (MAPK) signaling pathways in GS-002-treated cells. Furthermore, we found that GS-002 induced more cell apoptosis in ATF-3-overexpressing cells. These results suggest that the induction of apoptosis by the propolis derivative, GS-002, is partially mediated through ER stress and ATF-3-dependent pathways, and GS-002 has the potential for development as an antitumor drug.

Highly stable and degradable multifunctional microgel for self-regulated insulin delivery under physiological conditions.

The response to glucose, pH and temperature, high drug loading capacity, self-regulated drug delivery and degradation in vivo are simultaneously probable by applying a multifunctional microgel under a rational design in a colloid chemistry method. Such multifunctional microgels are fabricated with N-isopropylacrylamide (NIPAAm), (2-dimethylamino)ethyl methacrylate (DMAEMA) and 3-acrylamidephenylboronic acid (AAPBA) through a precipitation emulsion method and cross-linked by reductive degradable N,N'-bis(arcyloyl)cystamine (BAC). This novel kind of microgel with a narrow size distribution (∼250 nm) is suitable for diabetes because it can adapt to the surrounding medium of different glucose concentrations over a clinically relevant range (0-20 mM), control the release of preloaded insulin and is highly stable under physiological conditions (pH 7.4, 0.15 M NaCl, 37 °C). When synthesized multifunctional microgels regulate drug delivery, they gradually degrade as time passes and, as a result, show enhanced biocompatibility. This exhibits a new proof-of-concept for diabetes treatment that takes advantage of the properties of each building block from a multifunctional micro-object. These highly stable and versatile multifunctional microgels have the potential to be used for self-regulated therapy and monitoring of the response to treatment, or even simultaneous diagnosis as nanobiosensors.