Construction of gold nanoparticles by tubular polysaccharide from black fungus and their apoptosis-inducing activities in HepG2 cells

Gold nanoparticles (AuNPs) with size of 12 ~ 25 nm were loaded on the dendritic nanotubes (DNTs), which were self-assembled by the triple-helix polysaccharides from black fungus (AF1). The characterization results proved that the AuNPs were dispersed on the surface of DNTs without affecting their tubular structure. Due to the dendritic structure, the loading content of AuNPs could arrived at 46.4%. Moreover, the potential anticancer activities of the complex (DNT-Au) were evaluated by the induction of apoptosis in HepG2 cells. It was found DNT-Au could be taken up by cells and enter into lysosomes, further inducing apoptosis in HepG2 cells by ROS-mediated mitochondrial dysfunction. This work was benefit for the development of natural polysaccharide as a substrate to stabilize nanoparticles in biomedical fields.     

Sugar‐Based Arylsulfonamide Carboxylates as Selective and Water‐Soluble Matrix Metalloproteinase‐12 Inhibitors

Matrix metalloproteinase‐12 (MMP‐12) can be considered an attractive target to study selective inhibitors useful in the development of new therapies for lung and cardiovascular diseases. In this study, a new series of arylsulfonamide carboxylates, with increased hydrophilicity resulting from conjugation with a β‐N‐acetyl‐d ‐glucosamine moiety, were designed and synthesized as MMP‐12 selective inhibitors. Their inhibitory activity was evaluated on human MMPs by using the fluorimetric assay, and a crystallographic analysis was performed to characterize their binding mode. Among these glycoconjugates, a nanomolar MMP‐12 inhibitor with improved water solubility, compound 3 [(R)‐2‐(N‐(2‐(3‐(2‐acetamido‐2‐deoxy‐β‐d ‐glucopyranosyl)thioureido)ethyl)biphenyl‐4‐ylsulfonamido)‐3‐methylbutanoic acid], was identified.     

Matrix Metalloproteinase 13 Inhibitors for Modulation of Osteoclastogenesis: Enhancement of Solubility and Stability

Matrix metalloproteinase 13 (MMP-13) activity has been correlated to breast cancer bone metastasis. It has been proposed that MMP-13 contributes to bone metastasis through the promotion of osteoclastogenesis. To explore the mechanisms of MMP-13 action, we previously described a highly efficacious and selective MMP-13 inhibitor, RF036. Unfortunately, further pursuit of RF036 as a probe of MMP-13 in vitro and in vivo activities was not practical due to the limited solubility and stability of the inhibitor. Our new study has explored replacing the RF036 backbone sulfur atom and terminal methyl group to create inhibitors with more favorable pharmacokinetic properties. One compound, designated inhibitor 3 , in which the backbone sulfur and terminal methyl group of RF036 were replaced by nitrogen and oxetane, respectively, had comparable activity, selectivity, and membrane permeability to RF036, while exhibiting greatly enhanced solubility and stability. Inhibitor 3 effectively inhibited MMP-13-mediated osteoclastogenesis but spared collagenolysis, and thus represents a next-generation MMP-13 probe applicable for in vivo studies of breast cancer metastasis.     

Oxidative Damage to Mitochondria Enhanced by Ionising Radiation and Gold Nanoparticles in Cancer Cells

Gold nanoparticles (AuNP) can increase the efficacy of radiation therapy by sensitising tumor cells to radiation damage. When used in combination with radiation, AuNPs enhance the rate of cell killing; hence, they may be of great value in radiotherapy. This study assessed the effects of radiation and AuNPs on mitochondrial reactive oxygen species (ROS) generation in cancer cells as an adjunct therapeutic target in addition to the DNA of the cell. Mitochondria are considered one of the primary sources of cellular ROS. High levels of ROS can result in an intracellular state of oxidative stress, leading to permanent cell damage. In this study, human melanoma and prostate cancer cell lines, with and without AuNPs, were irradiated with 6-Megavolt X-rays at doses of 0–8 Gy. Indicators of mitochondrial stress were quantified using two techniques, and were found to be significantly increased by the inclusion of AuNPs in both cell lines. Radiobiological damage to mitochondria was quantified via increased ROS activity. The ROS production by mitochondria in cells was enhanced by the inclusion of AuNPs, peaking at ~4 Gy and then decreasing at higher doses. This increased mitochondrial stress may lead to more effectively kill of AuNP-treated cells, further enhancing the applicability of functionally-guided nanoparticles.     

基团贡献法预测含极性基团离子液体对气体的溶解选择性

室温离子液体是一种“绿色溶剂”,具有独特的气体溶解选择性.基于正规溶液理论,根据文献发表的常规咪唑盐离子液体对不同气体的溶解度数据,结合基团贡献法预测了常压下CO2、CH4、N2、CO在含氰基、醚键等极性基团的咪唑盐离子液体中的亨利系数,进而得到不同气体在该类离子液体中的溶解选择性.结果表明,极性基团的引入有助于提高咪...     

Design and Synthesis of Water-Soluble and Potent MMP-13 Inhibitors with Activity in Human Osteosarcoma Cells

Osteoarthritis is a degenerative disease, often resulting in chronic joint pain and commonly affecting elderly people. Current treatments with anti-inflammatory drugs are palliative, making the discovery of new treatments necessary. The inhibition of matrix metalloproteinase MMP-13 is a validated strategy to prevent the progression of this common joint disorder. We recently described polybrominated benzotriazole derivatives with nanomolar inhibitory activity and a promising selectivity profile against this collagenase. In this work, we have extended the study in order to explore the influence of bromine atoms and the nature of the S1′ heterocyclic interacting moiety on the solubility/selectivity balance of this type of compound. Drug target interactions have been assessed through a combination of molecular modeling studies and NMR experiments. Compound 9a has been identified as a water-soluble and highly potent inhibitor with activity in MG-63 human osteosarcoma cells.     

Biological Synthesis of Bioactive Gold Nanoparticles from Inonotus obliquus for Dual Chemo-Photothermal Effects against Human Brain Cancer Cells

The possibility for an ecologically friendly and simple production of gold nanoparticles (AuNPs) with Chaga mushroom (Inonotus obliquus) (Ch-AuNPs) is presented in this study. Chaga extract’s reducing potential was evaluated at varied concentrations and temperatures. The nanoparticles synthesized were all under 20 nm in size, as measured by TEM, which is a commendable result for a spontaneous synthesis method utilizing a biological source. The Ch-AuNPs showed anti-cancer chemotherapeutic effects on human brain cancer cells which is attributed to the biofunctionalization of the AuNPs with Chaga bioactive components during the synthesis process. Further, the photothermal ablation capability of the as-prepared gold nanoparticles on human brain cancer cells was investigated. It was found that the NIR-laser induced thermal ablation of cancer cells was effective in eliminating over 80% of the cells. This research projects the Ch-AuNPs as promising, dual modal (chemo-photothermal) therapeutic candidates for anti-cancer applications.     

Dendritic Cell-Based Immunotherapy in Multiple Myeloma: Challenges,Opportunities, and Future Directions

Immunotherapeutic approaches, including adoptive cell therapy, revolutionized treatment in multiple myeloma (MM). As dendritic cells (DCs) are professional antigen-presenting cells and key initiators of tumor-specific immune responses, DC-based immunotherapy represents an attractive therapeutic approach in cancer. The past years, various DC-based approaches, using particularly ex-vivo-generated monocyte-derived DCs, have been tested in preclinical and clinical MM studies. However, long-term and durable responses in MM patients were limited, potentially attributed to the source of monocyte-derived DCs and the immunosuppressive bone marrow microenvironment. In this review, we briefly summarize the DC development in the bone marrow niche and the phenotypical and functional characteristics of the major DC subsets. We address the known DC deficiencies in MM and give an overview of the DC-based vaccination protocols that were tested in MM patients. Lastly, we also provide strategies to improve the efficacy of DC vaccines using new, improved DC-based approaches and combination therapies for MM patients.     

Diesel exhaust particles modulate the tight junction protein occludin in lung cells in vitro

Background  

Using an in vitro triple cell co-culture model consisting of human epithelial cells (16HBE14o-), monocyte-derived macrophages and dendritic cells, it was recently demonstrated that macrophages and dendritic cells create a transepithelial network between the epithelial cells to capture antigens without disrupting the epithelial tightness. The expression of the different tight junction proteins in macrophages and dendritic cells, and the formation of tight junction-like structures with epithelial cells has been demonstrated. Immunofluorescent methods combined with laser scanning microscopy and quantitative real-time polymerase chain reaction were used to investigate if exposure to diesel exhaust particles (DEP) (0.5, 5, 50, 125 μg/ml), for 24 h, can modulate the expression of the tight junction mRNA/protein of occludin, in all three cell types.     

Development of benzophenone-based farnesyltransferase inhibitors as novel antimalarials

The development of farnesyltransferase inhibitors directed against Plasmodium falciparum is a strategy towards new drugs against malaria. Previously, we described benzophenone-based farnesyltransferase inhibitors with high in vitro antimalarial activity but no in vivo activity. Through the introduction of a methylpiperazinyl moiety, farnesyltransferase inhibitors with in vivo antimalarial activity were obtained. Subsequently, a structure-based design approach was chosen to further improve the antimalarial activity of this type of inhibitor. As no crystal structure of the farnesyltransferase of the target organism is available, homology modeling was used to reveal differences between the active sites of the rat/human and the P. falciparum farnesyltransferase. Based on flexible docking data, the piperazinyl moiety was replaced by a N,N,N'-trimethylethylenediamine moiety. This resulted in an inhibitor with significantly improved in vitro and in vivo antimalarial activity. Furthermore, this inhibitor displayed a notable increase in selectivity towards malaria parasites relative to human cells.     

Colloidal gold nanoparticle formation derived from self-assembled supramolecular structure of cyclodextrin/Au salt complex

We present a novel procedure for the formation of colloidal gold nanoparticles (AuNPs) derived from the supramolecular self-assembled structure of a cyclodextrin (CD)/Au salt complex (SCA) without the necessity for additional reducing or stabilizing agents. The SCA served as a solid template for the formation of gold seeds by solid-state thermal treatment within the confining environment of the α-CD, i.e., the matrix of the SCA. Subsequently, thermally treated SCA, denoted as T-SCA, was placed (without further treatment) into an aqueous medium and gold seeds were nucleated for the formation of α-CD-stabilized AuNPs at room temperature. The surface topology of SCA, as revealed by field-emission scanning electron microscopy (FE-SEM), consisted of flaky plate-like structures. Wide angle X-ray diffraction (WXRD) revealed that the surface topology of SCA resulted from a transformation in the crystalline structure of α-CD from the cage-type to the hexagonally ordered channel-type. The structure transformation on the surface of SCA was attributed to the nucleated self-assembly of surface α-CD molecules by Au salt. From combined FE-SEM, energy-dispersed X-ray spectroscopy (EDXS), WXRD and differential scanning calorimetry (DSC) results, it was concluded that the thermal treatment of SCA led to the formation of gold seeds, attributed to the reduction and aggregation of some Au salt molecules, confined within the interface between the cage-type and channel type structure of the SCA. After placement of T-SCA into an aqueous solution, the growth and stabilization of AuNPs by α-CD were verified by UV-vis spectroscopy. The formation of AuNPs, by this novel method, can be considered a one step seed-mediated growth process. The resulting AuNPs are spherical in morphology, narrowly size distributed and possesses excellent stability. Furthermore, the AuNPs size is tunable by simply controlling water content during nanoparticle growth.     

Dispersion Function of a Protein,DP-1, Identified in Collimonas sp. D-25, for the Synthesis of Gold Nanoparticles

Collimonas sp. (D-25), found in the soil of Akita Prefecture, is a gram-negative bacterium with the ability to synthesize gold nanoparticles (AuNPs). During the synthesis of AuNPs, one specific protein (DP-1) was found to have disappeared in the sonicated solution of the bacterium. Recombinant DP-1 (rDP-1) from Escherichia coli BL21 (DE3) was used to study the effect of DP-1 on the synthesis of AuNPs. AuNPs synthesized with rDP-1 result in small, stabilized nanoparticles. AuNPs synthesized by DP-1 retained the stability of both the dispersion and nano-size particles under high salt concentrations. Isothermal titration calorimetry was employed to investigate the bonding ratio of rDP-1 to AuNPs. Several thousand rDP-1 proteins are attached to the surface of an AuNP to form a protein corona containing multiple layers. These results suggest that DP-1 obtained from D-25 has a size and stability control function during AuNP synthesis.     

A Centrifugation-based Method for Preparation of Gold Nanoparticles and its Application in Biodetection

Gold nanoparticles (AuNPs) have found widespread applications in life sciences. While synthesis of monodispersed AuNPs has been fairly convenient by using chemical reduction of chloroauric acid by sodium citrate, we found that AuNPs of high quality and high concentrations were not readily obtained via this method. As an example, we showed that monodispersed 13-nm AuNPs were readily synthesized at relatively low concentrations (e.g. 3.5 nM); in contrast, 13-nm AuNPs of 17 nM obtained by the direct reduction method were irregularly shaped and not well dispersed. In this work, we demonstrated that AuNPs of high concentration could be prepared by a two-step approach, i.e. chemical reduction at low concentrations and subsequent centrifugation. Compared to the direct reduction method, this new two-step method led to AuNPs with high salt resistance and high stability, which are essential for the preparation of DNA-AuNPs conjugates for DNA biodetection.     

Size- and time-dependent alteration in metabolic activities of human hepatic cytochrome P450 isozymes by gold nanoparticles via microsomal coincubations

Nano-sized particles are known to interfere with drug-metabolizing cytochrome P450 (CYP) enzymes, which can be anticipated to be a potential source of unintended adverse reactions, but the mechanisms underlying the inhibition are still not well understood. Herein we report a systematic investigation of the impacts of gold nanoparticles (AuNPs) on five major CYP isozymes under in vitro incubations of human liver microsomes (HLMs) with tannic acid (TA)-stabilized AuNPs in the size range of 5 to 100 nm. It is found that smaller AuNPs show more pronounced inhibitory effects on CYP2C9, CYP2C19, CYP2D6, and CYP3A4 in a dose-dependent manner, while 1A2 is the least susceptible to the AuNP inhibition. The size- and dose-dependent CYP-specific inhibition and the nonspecific drug-nanogold binding in the coincubation media can be significantly reduced by increasing the concentration ratio of microsomal proteins to AuNPs, probably via a noncompetitive mode. Remarkably, AuNPs are also found to exhibit a slow time-dependent inactivation of 2D6 and 3A4 in a β-nicotinamide adenine dinucleotide 2′-phosphate reduced tetrasodium salt hydrate (NADPH)-independent manner. During microsomal incubations, UV–vis spectroscopy, dynamic light scattering, and zeta-potential measurements were used to monitor the changes in particle properties under the miscellaneous AuNP/HLM/CYP dispersion system. An improved stability of AuNPs by mixing HLM with the gold nanocolloid reveals that the stabilization via AuNP-HLM interactions may occur on a faster time scale than the salt-induced nanoaggregation by incubation in phosphate buffer. The results suggest that the AuNP induced CYP inhibition can be partially attributed to its adhesion onto the enzymes to alter their structural conformations or onto the HLM membrane therefore impairing the integral membrane proteins. Additionally, AuNPs likely block the substrate pocket on the CYP surface, depending on both the particle characteristics and the structural diversity of the isozymes. These findings may represent additional mechanisms for the differential inhibitory effects arising from the coincubated AuNPs on the metabolic activities of the hepatic CYP isozymes.     

Arxula adeninivorans LS3 as suitable biosensor for measurements of biodegradable substances in salt water

A microbial amperometric sensor based on the yeast Arxula adeninivorans was tested to determine its suitability for measuring biochemical oxygen demand (BOD) in salt water. The viability of cells immobilized onto the sensor membrane was hardly influenced up to 10% (w/v) NaCl in the sample, although the solubility of oxygen was affected. NaCl concentrations higher than 10% (w/v) caused a marked decrease in the oxygen solubility and deactivated the sensor. This outcome depended on the substrates used, e.g., alanine-, galactose- and acetic acid-sensor signals were influenced by any salt concentration whereas glucose-, glycerol-, maltose- and arginine-sensor signals were influenced only by higher salt concentrations. Sensor signals from yeast extract as well as glucose correlated with the quantity of these substances and with the salt concentration contained in the water. This correlation was linear up to 10% (w/v) NaCl and 0·125% (w/v) yeast extract or up to 10% (w/v) NaCl and 0·125% (w/v) glucose in the sample. The sensor signals are therefore influenced only by NaCl-determined solubility of oxygen and not by the physiological parameters of the immobilized cells. However, an increase of yeast extract- or glucose-concentrations in the presence of NaCl caused physiological effects on the sensor cells. © 1998 Society of Chemical Industry     

Efficient pH Dependent Drug Delivery to Target Cancer Cells by Gold Nanoparticles Capped with Carboxymethyl Chitosan

Doxorubicin (DOX) was immobilized on gold nanoparticles (AuNPs) capped with carboxymethyl chitosan (CMC) for effective delivery to cancer cells. The carboxylic group of carboxymethyl chitosan interacts with the amino group of the doxorubicin (DOX) forming stable, non-covalent interactions on the surface of AuNPs. The carboxylic group ionizes at acidic pH, thereby releasing the drug effectively at acidic pH suitable to target cancer cells. The DOX loaded gold nanoparticles were effectively absorbed by cervical cancer cells compared to free DOX and their uptake was further increased at acidic conditions induced by nigericin, an ionophore that causes intracellular acidification. These results suggest that DOX loaded AuNPs with pH-triggered drug releasing properties is a novel nanotheraputic approach to overcome drug resistance in cancer.     

Sitagliptin Modulates the Response of Ovarian Cancer Cells to Chemotherapeutic Agents

The strong association between diabetes mellitus type 2 and cancer is observed. The incidence of both diseases is increasing globally due to the interaction between them. Recent studies suggest that there is also an association between cancer incidence and anti-diabetic medications. An inhibitor of dipeptidyl-peptidase 4 (DPP-4), sitagliptin, is used in diabetes treatment. We examined the influence of sitagliptin alone or in combination with a cytostatic drug (paclitaxel) on the development of epithelial ovarian cancer cells and the process of metastasis. We examined migration, invasiveness, apoptosis, and metalloproteinases (MMPs) and their inhibitors’ (TIMPs) production in two human ovarian cancer cell lines. Sitagliptin induced apoptosis by caspase 3/7 activation in paclitaxel-treated SKOV-3 and OVCAR-3 cells. Sitagliptin maintained paclitaxel influence on ERK and Akt signaling pathways. Sitagliptin additionally reduced migration and invasiveness of SKOV-3 cells. There were distinct differences of metalloproteinases production in sitagliptin-stimulated ovarian cancer cells in both cell lines, despite their identical histological classification. Only the SKOV-3 cell line expressed MMPs and TIMPs. SKOV-3 cells co-treated with sitagliptin and paclitaxel decreased concentrations of MMP-1, MMP-2, MMP-7, MMP-10, TIMP-1, TIMP-2. The obtained data showed that sitagliptin used with paclitaxel may be considered as a possibility of pharmacological modulation of intracellular transmission pathways to improve the response to chemotherapy.     

Sugar-dependent solubility and fluorescence property of copolymers consisting of phenylboronic acid and 2-hydroxyethyl methacrylate moieties

Copolymers consisting of N-3-acrylamidophenylboronic acid (APBA) and 2-hydroxyethyl methacrylate moieties (HEMA) were synthesized and their solubility and fluorescence properties were evaluated in the presence of sugar. The APBA–HEMA copolymer composed of 25 mol% of APBA moiety was found to be poorly soluble in water at pH 7.4. However, the water solubility of APBA–HEMA was improved in the presence of fructose in solution. The solubility of APBA–HEMA was influenced by fructose in a concentration-dependent manner, due to the formation of boronate ester of APBA moiety with fructose added. In addition, APBA–HEMA was modified with fluorescein isothiocyanate (FITC) for the fluorometric detection of sugars. The fluorescence intensity of FITC-modified APBA–HEMA was dependent on the type and concentration of sugars in solution. The fluorescence intensity of FITC-modified APBA–HEMA was highly enhanced by the addition of fructose, while the fluorescent response was negligibly small when other sugars were added. Thus, usefulness of FITC-modified APBA–HEMA for the selective determination of fructose was demonstrated.