A food-derived bioactive peptide that works as an important antioxidant in vivo could be used to remedy oxidative stress-related diseases. Alzheimer's disease (AD) is influenced by the accumulation and deposition of amyloid beta (Aβ) peptides in vivo, and such accumulation may worsen under conditions of oxidative stress. This study aimed to assess whether a tetrapeptide from maize, TPM, could protect Caenorhabditis elegans against Aβ-induced disease and to clarify the possible mechanism of such protection, as well as contribute to a model of oxidative stress that influences the process of Alzheimer's disease. These parameters were tested in a C. elegans model of full-length Aβ1-42 expression (GMC101). TPM at 10 mM alleviated Aβ-induced paralysis in GMC101 under oxidative stress and normal conditions. Further studies demonstrated that TPM can efficiently inhibit Aβ aggregation in vitro and scavenge reactive oxygen species (ROS) that accelerate the accumulation and deposition of Aβ peptides in vivo. In addition, Aβ1-42 dimer and Aβ1-42 trimer were down-regulated by TPM under both oxidative stress and normal conditions. Our observations lead to the hypothesis that the bioactive peptide, TPM, is a potential drug candidate that might efficiently alleviate the symptoms of AD.

•Apoferritin paired gold clusters exhibit high peroxidase-like activity.•They possess high stability and activity under harsh conditions.•Apoferritin nanocage could enhance catalyze the oxidation of TMB by H2O2 to produce a blue color reaction.•Apoferritin paired gold clusters-based enzymatic spectrophotometric analysis of glucose was performed.The discovery and application of noble metal nanoclusters have received considerable attention. In this paper, we reported that apoferritin paired gold clusters (Au–Ft) could efficiently catalyze oxidation of 3.3′,5.5′-tetramethylbenzidine (TMB) by H2O2 to produce a blue color reaction. Compared with natural enzyme, Au–Ft exhibited higher activity near acidic pH and could be used over a wide range of temperatures. Apoferritin nanocage enhanced the reaction activity of substrate TMB by H2O2. The reaction catalyzed by Au–Ft was found to follow a typical Michaelis–Menten kinetics. The kinetic parameters exhibited a lower Km value (0.097 mM) and a higher Kcat value (5.8×104 s−1) for TMB than that of horse radish peroxidase (HRP). Base on these findings, Au–Ft, acting as a peroxidase mimetic, performed enzymatic spectrophotometric analysis of glucose. This system exhibited acceptable reproducibility and high selectivity in biosening, suggesting that it could have promising applications in the future.

Organic/inorganic nanohybrids, which integrate advantages of the biocompatibility of organic polymers and diversified functionalities of inorganic nanoparticles, have been extensively investigated in recent years. Herein, we report the construction of arginine-glycine-aspartic acid-cysteine (RGDC) tetrapeptide functionalized and 10-hydroxycamptothecin (HCPT)-encapsulated magnetic nanohybrids (RFHEMNs) for integrin αVβ3-targeted drug delivery. The obtained RFHEMNs were near-spherical in shape with a homogeneous size about 50 nm, and exhibited a superparamagnetic behavior. In vitro drug release study showed a sustained and pH-dependent release profile. Cell viability tests revealed that RFHEMNs displayed a significant enhancement of cytotoxicity against αVβ3-overexpressing A549 cells, as compared to free HCPT and nontargeting micelles. Flow cytometry analysis indicated that this cytotoxic effect was associated with dose-dependent S phase arrest. Finally, RFHEMNs exerted encouraging anti-cell-migration activity as determined by an in vitro wound-healing assay and a transwell assay. Overall, we envision that this tumor-targeting nanoscale drug delivery system may be of great application potential in chemotherapy of primary tumor and their metastases.Keywords: anti-cell-migration; antitumor efficacy; cell cycle; integrin targeting; magnetic nanohybrids; RGDC tetrapeptide

A new route was described to synthesize Arg-Gly-Asp-X(RGDX, X=amino acid) tetrapeptide. To better understand the method, the tetrapeptide Arg-Gly-Asp-CySS(RGDCySS) was chosen as a model target for X. First, GDCySS was obtained in four steps, comprising the chloroacetylation of L-aspartic acid(ClCH2COAsp), synthesis of chloroacetyl L-aspartic acid anhydride[ClCH2COAsp(CO)2O], formation of ClCH2COAsp-CySS and ammonolysis of ClCH2COAsp-CySS. Second, preparation of Arg-NCA, which was coupled with GDCySS to synthesize RGDCySS by the NCA method(Leuchs’ anhydrides method, NCA: N-carboxy-α-amino acid anhydride). The purity of the product was analyzed by the high performance liquid chromatography(HPLC). Molecular weights of the peptide products were confirmed by mass spectroscopy. In the developed approach, less protected amino acids were used compared to conventional solid-phase synthesis. The new route offers advantages of low cost, simplicity and rapid synthesis with a reasonable yield of 63.0%(calculated according to arginine content).

A double-targeted magnetic nanocarrier based with potential applications in the delivery of hydrophobic drugs has been developed. It consists of magnetite (Fe3O4) nanoparticles encapsulated in self-assembled micelles of the amphiphilic copolymer MPEG–PLGA [methoxy poly (ethylene glycol)-poly (d,l-lactide-co-glycolide)], and was fabricated using the solvent-evaporation technique. The magnetic nanocarrier has a very stable core–shell structure and is superparamagnetic. Its cytotoxicity was evaluated using the MTT assay with three cell lines—HeLa, MCF-7, and HT1080; it exhibited no cytotoxicity against any tested line at concentrations of up to 400 μg/mL after incubation for 24 h. Its cellular uptake was studied by Prussian blue staining and by fluorescence microscopy after encapsulating a fluorescent probe (hydrophobic quantum dots) into the nanocarrier. Finally, the magnetic targeting property of the magnetic nanocarrier was confirmed by an in vitro test. Overall, the results obtained demonstrate the potential of the double-targeted nanocarrier for the intracellular delivery of hydrophobic drugs.Graphical abstractHighlights► A potential double-targeted magnetic nanocarrier for drug delivery was fabricated. ► Magnetic nanocarrier exhibits substantial stability and superparamagnetic property. ► Magnetic nanocarrier has no cytotoxicity to three tested cancer cell lines. ► Efficient cellular uptake of the magnetic nanocarrier by HeLa cells. ► Magnetic nanocarrier can accumulate at the targeted area under a magnetic field.