Effect of Orthostatic Hypotension on Kidney Function.

BACKGROUND: The association between orthostatic hypotension (OH) and long-term changes in kidney function in the general population is not yet well known. METHODS: We performed a population-based cohort study based on data from the Korean Genome and Epidemiology Study (KoGES). The primary exposure was the presence of classic OH, defined as a postural drop in blood pressure (systolic blood pressure ≥20 mm Hg and/or diastolic blood pressure ≥10 mm Hg) at 2 min of standing after 5 min of supine rest. The primary outcome was a 12-year change in kidney function, assessed by subtracting the baseline estimated glomerular filtration rate (eGFR) from the eGFR at 12 years of follow-up. RESULTS: Our study included 5,905 participants (median [interquartile range] age, 49 [44-58] years; 46% males) who met inclusion and exclusion criteria. Classic OH was detected in 268 (4.5%) of the total participants. In the regression analyses, participants with classic OH had a greater decline in eGFR over 12 years compared with those without classic OH; the fully adjusted beta coefficient and 95% confidence intervals (95% CIs) were -1.74 (-3.07, -0.40). Furthermore, classic OH was associated with 27% greater risk of a 30% decline in kidney function compared with those without classic OH; fully adjusted hazard ratio and 95% CIs were 1.27 (1.07, 1.49). CONCLUSIONS: Classic OH can negatively affect long-term kidney function in the general population.

Bakuchiol, main component of root bark of Ulmus davidiana var. japonica, inhibits TGF-ß-induced in vitro EMT and in vivo metastasis.

Cancer is a second leading cause of death worldwide, and metastasis is the major cause of cancer-related mortality. The epithelial-mesenchymal transition (EMT), known as phenotypic change from epithelial cells to mesenchymal cells, is a crucial biological process during development. However, inappropriate activation of EMT contributes to tumor progression and promoting metastasis; therefore, inhibiting EMT is considered a promising strategy for developing drugs that can treat or prevent cancer. In the present study, we investigated the anti-cancer effect of bakuchiol (BC), a main component of Ulmus davidiana var. japonica, in human cancer cells using A549, HT29 and MCF7 cells. In MTT and colony forming assay, BC exerted cytotoxicity activity against cancer cells and inhibited proliferation of these cells. Anti-metastatic effects by BC were further confirmed by observing decreased migration and invasion in TGF-ß-induced cancer cells after BC treatment. Furthermore, BC treatment resulted in increase of E-cadherin expression and decrease of Snail level in Western blotting and immunofluorescence analysis, supporting its anti-metastatic activity. In addition, BC inhibited lung metastasis of tail vein injected human cancer cells in animal model. These findings suggest that BC inhibits migration and invasion of cancers by suppressing EMT and in vivo metastasis, thereby may be a potential therapeutic agent for treating cancers.

Amentoflavone, active compound of Selaginella tamariscina, inhibits in vitro and in vivo TGF-ß-induced metastasis of human cancer cells.

Epithelial mesenchymal transition (EMT) is a well-known and important step in metastasis and thus can be a key target in cancer treatment. Here, we tested the EMT inhibitory actions of Selaginella tamariscina and its active component, amentoflavone (AF). EMT was examined in vitro using wound-healing and invasion assays and by monitoring changes in the expression of the EMT-related proteins, E-cadherin, Snail, and Twist. Metastasis was examined in vivo using SCID mice injected with luciferase-labeled A549 cells. We confirmed that aqueous extracts of S. tamariscina (STE) and AF inhibited EMT in human cancer cell lines. We found that STE and AF at nontoxic concentrations exerted remarkable inhibitory effects on migration (wound healing assay) and invasion (Transwell assay) in tumor necrosis factor (TGF)-ß-treated cancer cells. Western blotting and immunofluorescence imaging show that AF treatment also restored E-cadherin expression in these cells compared to cells treated with TGF-ß only. Suppression of metastasis by AF was investigated by monitoring migration of tail-vein-injected, circulating A549-luc cells to the lungs in mice. After 3 wk, fewer nodules were observed in mice co-treated with AF compared with those treated with TGF-ß only. Our findings indicate that STE and AF are promising EMT inhibitors and, ultimately, potentially potent antitumor agents.

Effects of tumor microenvironments on targeted delivery of glycol chitosan nanoparticles.

In cancer theranostics, the main strategy of nanoparticle-based targeted delivery system has been understood by enhanced permeability and retention (EPR) effect of macromolecules. Studies on diverse nanoparticles provide a better understanding of different EPR effects depending on their structure, physicochemical properties, and chemical modifications. Recently the tumor microenvironment has been considered as another important factor for determining tumor-targeted delivery of nanoparticles, but the correlation between EPR effects and tumor microenvironment has not yet been fully elucidated. Herein, ectopic subcutaneous tumor models presenting different tumor microenvironments were established by inoculation of SCC7, U87, HT29, PC3, and A549 cancer cell lines into athymic nude mice, respectively. In the five different types of tumor-bearing mice, tumor-targeted delivery of self-assembled glycol chitosan nanoparticles (CNPs) were comparatively evaluated to identify the correlation between the tumor microenvironments and targeted delivery of CNPs. As a result, neovascularization and extents of intratumoral extracellular matrix (ECM) were both important in determining the tumor targeted delivery of CNPs. The EPR effect was maximized in the tumors which include large extent of angiogenic blood vessels and low intratumoral ECM content. This comprehensive study provides substantial evidence that the EPR effects based tumor-targeted delivery of nanoparticles can be different depending on the tumor microenvironment in individual tumors. To overcome current limitations in clinical nanomedicine, the tumor microenvironment of the patients and EPR effects in clinical tumors should also be carefully studied.

Nano-sized metabolic precursors for heterogeneous tumor-targeting strategy using bioorthogonal click chemistry in vivo.

Herein, we developed nano-sized metabolic precursors (Nano-MPs) for new tumor-targeting strategy to overcome the intrinsic limitations of biological ligands such as the limited number of biological receptors and the heterogeneity in tumor tissues. We conjugated the azide group-containing metabolic precursors, triacetylated N-azidoacetyl-d-mannosamine to generation 4 poly(amidoamine) dendrimer backbone. The nano-sized dendrimer of Nano-MPs could generate azide groups on the surface of tumor cells homogeneously regardless of cell types via metabolic glycoengineering. Importantly, these exogenously generated 'artificial chemical receptors' containing azide groups could be used for bioorthogonal click chemistry, regardless of phenotypes of different tumor cells. Furthermore, in tumor-bearing mice models, Nano-MPs could be mainly localized at the target tumor tissues by the enhanced permeation and retention (EPR) effect, and they successfully generated azide groups on tumor cells in vivo after an intravenous injection. Finally, we showed that these azide groups on tumor tissues could be used as 'artificial chemical receptors' that were conjugated to bioorthogonal chemical group-containing liposomes via in vivo click chemistry in heterogeneous tumor-bearing mice. Therefore, overall results demonstrated that our nano-sized metabolic precursors could be extensively applied to new alternative tumor-targeting technique for molecular imaging and drug delivery system, regardless of the phenotype of heterogeneous tumor cells.

In vivo stem cell tracking with imageable nanoparticles that bind bioorthogonal chemical receptors on the stem cell surface.

It is urgently necessary to develop reliable non-invasive stem cell imaging technology for tracking the in vivo fate of transplanted stem cells in living subjects. Herein, we developed a simple and well controlled stem cell imaging method through a combination of metabolic glycoengineering and bioorthogonal copper-free click chemistry. Firstly, the exogenous chemical receptors containing azide (-N3) groups were generated on the surfaces of stem cells through metabolic glycoengineering using metabolic precursor, tetra-acetylated N-azidoacetyl-d-mannosamine(Ac4ManNAz). Next, bicyclo[6.1.0]nonyne-modified glycol chitosan nanoparticles (BCN-CNPs) were prepared as imageable nanoparticles to deliver different imaging agents. Cy5.5, iron oxide nanoparticles and gold nanoparticles were conjugated or encapsulated to BCN-CNPs for optical, MR and CT imaging, respectively. These imageable nanoparticles bound chemical receptors on the Ac4ManNAz-treated stem cell surface specifically via bioorthogonal copper-free click chemistry. Then they were rapidly taken up by the cell membrane turn-over mechanism resulting in higher endocytic capacity compared non-specific uptake of nanoparticles. During in vivo animal test, BCN-CNP-Cy5.5-labeled stem cells could be continuously tracked by non-invasive optical imaging over 15 days. Furthermore, BCN-CNP-IRON- and BCN-CNP-GOLD-labeled stem cells could be efficiently visualized using in vivo MR and CT imaging demonstrating utility of our stem cell labeling method using chemical receptors. These results conclude that our method based on metabolic glycoengineering and bioorthogonal copper-free click chemistry can stably label stem cells with diverse imageable nanoparticles representing great potential as new stem cell imaging technology.

Extracellular matrix remodeling in vivo for enhancing tumor-targeting efficiency of nanoparticle drug carriers using the pulsed high intensity focused ultrasound.

Dense and stiff extracellular matrix (ECM) in heterogeneous tumor tissues can inhibit deep penetration of nanoparticle drug carriers and decreases their therapeutic efficacy. Herein, we suggest the ECM remodeling strategy by the pulsed high intensity focused ultrasound (Pulsed-HIFU) technology for enhanced tumor-targeting of nanoparticles. First, we clearly observed that the tumor-targeting efficacy and tissue penetration of intravenously injected Cy5.5-labled glycol chitosan nanoparticles (Cy5.5-CNPs) were greatly inhibited in tumor tissue containing high collagen and hyaluronan contents in ECM-rich A549 tumor-bearing mice, compared to in ECM-less SCC7. When collagenase or hyaluronidase was treated by intra-tumoral injection, the amount of collagen and hyaluronan decreased in ECM-rich A549 tumor tissues and more Cy5.5-CNPs penetrated inside the tumor tissue, confirmed using non-invasive optical imaging. Finally, in order to break down the stiff ECM structure, ECM-rich A549 tumor tissues were treated with the relatively low power of Pulse-HIFU (20W/cm2), wherein acute tissue damage was not observed. As we expected, the A549 tumor tissues showed the remodeling of ECM structure after non-invasive Pulsed-HIFU exposure, which resulted in the increased blood flow, decreased collagen contents, and enhanced penetration of CNPS. Importantly, the tumor targeting efficiency in Pulsed-HIFU-treated A549 tumor tissues was 2.5 times higher than that of untreated tumor tissues. These overall results demonstrate that ECM remodeling and disruption of collagen structure by Pulse-HIFU is promising strategy to enhance the deep penetration and enhanced tumor targeting of nanoparticles in ECM-rich tumor tissues.

Artificial Chemical Reporter Targeting Strategy Using Bioorthogonal Click Reaction for Improving Active-Targeting Efficiency of Tumor.

Biological ligands such as aptamer, antibody, glucose, and peptide have been widely used to bind specific surface molecules or receptors in tumor cells or subcellular structures to improve tumor-targeting efficiency of nanoparticles. However, this active-targeting strategy has limitations for tumor targeting due to inter- and intraheterogeneity of tumors. In this study, we demonstrated an alternative active-targeting strategy using metabolic engineering and bioorthogonal click reaction to improve tumor-targeting efficiency of nanoparticles. We observed that azide-containing chemical reporters were successfully generated onto surface glycans of various tumor cells such as lung cancer (A549), brain cancer (U87), and breast cancer (BT-474, MDA-MB231, MCF-7) via metabolic engineering in vitro. In addition, we compared tumor targeting of artificial azide reporter with bicyclononyne (BCN)-conjugated glycol chitosan nanoparticles (BCN-CNPs) and integrin αvß3 with cyclic RGD-conjugated CNPs (cRGD-CNPs) in vitro and in vivo. Fluorescence intensity of azide-reporter-targeted BCN-CNPs in tumor tissues was 1.6-fold higher and with a more uniform distribution compared to that of cRGD-CNPs. Moreover, even in the isolated heterogeneous U87 cells, BCN-CNPs could bind artificial azide reporters on tumor cells more uniformly (∼92.9%) compared to cRGD-CNPs. Therefore, the artificial azide-reporter-targeting strategy can be utilized for targeting heterogeneous tumor cells via bioorthogonal click reaction and may provide an alternative method of tumor targeting for further investigation in cancer therapy.

Engineered Human Ferritin Nanoparticles for Direct Delivery of Tumor Antigens to Lymph Node and Cancer Immunotherapy.

Efficient delivery of tumor-specific antigens (TSAs) to lymph nodes (LNs) is essential to eliciting robust immune response for cancer immunotherapy but still remains unsolved. Herein, we evaluated the direct LN-targeting performance of four different protein nanoparticles with different size, shape, and origin [Escherichia coli DNA binding protein (DPS), Thermoplasma acidophilum proteasome (PTS), hepatitis B virus capsid (HBVC), and human ferritin heavy chain (hFTN)] in live mice, using an optical fluorescence imaging system. Based on the imaging results, hFTN that shows rapid LN targeting and prolonged retention in LNs was chosen as a carrier of the model TSA [red fluorescence protein (RFP)], and the flexible surface architecture of hFTN was engineered to densely present RFPs on the hFTN surface through genetic modification of subunit protein of hFTN. The RFP-modified hFTN rapidly targeted LNs, sufficiently exposed RFPs to LN immune cells during prolonged period of retention in LNs, induced strong RFP-specific cytotoxic CD8+ T cell response, and notably inhibited RFP-expressing melanoma tumor growth in live mice. This suggests that the strategy using protein nanoparticles as both TSA-carrying scaffold and anti-cancer vaccine holds promise for clinically effective immunotherapy of cancer.

Precise Targeting of Liver Tumor Using Glycol Chitosan Nanoparticles: Mechanisms, Key Factors, and Their Implications.

Herein, we elucidated the mechanisms and key factors for the tumor-targeting ability of nanoparticles that presented high targeting efficiency for liver tumor. We used several different nanoparticles with sizes of 200-300 nm, including liposome nanoparticles (LNPs), polystyrene nanoparticles (PNPs) and glycol chitosan-5ß-cholanic acid nanoparticles (CNPs). Their sizes are suitable for the enhanced permeation and retention (EPR) effect in literature. Different in vitro characteristics, such as the particle structure, stability, and bioinertness, were carefully analyzed with and without serum proteins. Also, pH-dependent tumor cell uptakes of nanoparticles were studied using fluorescence microscopy. Importantly, CNPs had sufficient stability and bioinertness to maintain their nanoparticle structure in the bloodstream, and they also presented prolonged circulation time in the body (blood circulation half-life T1/2 = about 12.2 h), compared to the control nanoparticles. Finally, employing liver tumor bearing mice, we also observed that CNPs had excellent liver tumor targeting ability in vivo, while LNPs and PNPs demonstrated lower tumor-targeting efficiency due to the nonspecific accumulation in normal liver tissue. Liver tumor models were produced by laparotomy and direct injection of HT29 tumor cells into the left lobe of the liver of athymic nude mice. This study provides valuable information concerning the key factors for the tumor-targeting ability of nanoparticles such as stability, bioinertness, and rapid cellular uptake at targeted tumor tissues.

Predicting the in vivo accumulation of nanoparticles in tumor based on in vitro macrophage uptake and circulation in zebrafish.

Nanoparticles have resulted in great progress in biomedical imaging and targeted drug delivery in cancer theranostics. To develop nanoparticles as an effective carrier system for therapeutics, chemical structures and physicochemical properties of nanoparticle may provide a reliable means to predict the in vitro characteristics of nanoparticles. However, in vivo fates of nanoparticles, such as pharmacokinetics and tumor targeting efficiency of nanoparticles, have been difficult to predict beforehand. To predict the in vivo fates of nanoparticles in tumor-bearing mice, differences in physicochemical properties and in vitro cancer cell/macrophage uptake of 5 different nanoparticles with mean diameter of 200-250nm were comparatively analyzed, along with their circulation in adult zebrafish. The nanoparticles which showed favorable cellular uptake by macrophages indicated high unintended liver accumulation in vivo, which is attributed to the clearance by the reticuloendothelial system (RES). In addition, blood circulation of nanoparticles was closely correlated in adult zebrafish and in mice that the zebrafish experiment may elucidate the in vivo behavior of nanoparticles in advance of the in vivo experiment using mammal animal models. This comparative study on various nanoparticles was conducted to provide the basic information on predicting the in vivo fates of nanoparticles prior to the in vivo experiments.

In vivo monitoring of angiogenesis in a mouse hindlimb ischemia model using fluorescent peptide-based probes.

Vascular endothelial growth factor receptor (VEGFR) and matrix metalloproteinase (MMP) are up-regulated in ischemic tissue and play pivotal roles in promoting angiogenesis. The purpose of the present study was to evaluate two fluorophore-conjugated peptide probes specific to VEGFR and MMP for dual-targeted in vivo monitoring of angiogenesis in a murine model of hindlimb ischemia. To this end, VEGFR-Probe and MMP-Probe were developed by conjugating distinct near-infrared fluorophores to VEGFR-binding and MMP substrate peptides, respectively. VEGFR-Probe exhibited specific binding to VEGFR on HUVECs, and self-quenched MMP-Probe produced strong fluorescence intensity in the presence of MMPs in vitro. Subsequently, VEGFR-Probe and MMP-Probe were successfully utilized for time course in vivo visualization of VEGFR or MMP, respectively. Simultaneous visualization provided information regarding the spatial distribution of these proteins, including areas of co-localization. This dual-targeted in vivo imaging approach will be useful for understanding the detailed mechanism of angiogenesis and for evaluating therapeutic angiogenesis.

T1-Weighted MR imaging of liver tumor by gadolinium-encapsulated glycol chitosan nanoparticles without non-specific toxicity in normal tissues.

Herein, we have synthesized Gd(iii)-encapsulated glycol chitosan nanoparticles (Gd(iii)-CNPs) for tumor-targeted T1-weighted magnetic resonance (MR) imaging. The T1 contrast agent, Gd(iii), was successfully encapsulated into 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-modified CNPs to form stable Gd(iii)-encapsulated CNPs (Gd(iii)-CNPs) with an average particle size of approximately 280 nm. The stable nanoparticle structure of Gd(iii)-CNPs is beneficial for liver tumor accumulation by the enhanced permeation and retention (EPR) effect. Moreover, the amine groups on the surface of Gd(iii)-CNPs could be protonated and could induce fast cellular uptake at acidic pH in tumor tissue. To assay the tumor-targeting ability of Cy5.5-labeled Gd(iii)-CNPs, near-infrared fluorescence (NIRF) imaging and MR imaging were used in a liver tumor model as well as a subcutaneous tumor model. Cy5.5-labeled Gd(iii)-CNPs generated highly intense fluorescence and T1 MR signals in tumor tissues after intravenous injection, while DOTAREM®, the commercialized control MR contrast agent, showed very low tumor-targeting efficiency on MR images. Furthermore, damaged tissues were found in the livers and kidneys of mice injected with DOTAREM®, but there were no obvious adverse effects with Gd(iii)-CNPs. Taken together, these results demonstrate the superiority of Gd(iii)-CNPs as a tumor-targeting T1 MR agent.

Bioorthogonal Copper Free Click Chemistry for Labeling and Tracking of Chondrocytes In Vivo.

Establishment of an appropriate cell labeling and tracking method is essential for the development of cell-based therapeutic strategies. Here, we are introducing a new method for cell labeling and tracking by combining metabolic gylcoengineering and bioorthogonal copper-free Click chemistry. First, chondrocytes were treated with tetraacetylated N-azidoacetyl-D-mannosamine (Ac4ManNAz) to generate unnatural azide groups (-N3) on the surface of the cells. Subsequently, the unnatural azide groups on the cell surface were specifically conjugated with near-infrared fluorescent (NIRF) dye-tagged dibenzyl cyclooctyne (DBCO-650) through bioorthogonal copper-free Click chemistry. Importantly, DBCO-650-labeled chondrocytes presented strong NIRF signals with relatively low cytotoxicity and the amounts of azide groups and DBCO-650 could be easily controlled by feeding different amounts of Ac4ManNAz and DBCO-650 to the cell culture system. For the in vivo cell tracking, DBCO-650-labeled chondrocytes (1 × 10(6) cells) seeded on the 3D scaffold were subcutaneously implanted into mice and the transplanted DBCO-650-labeled chondrocytes could be effectively tracked in the prolonged time period of 4 weeks using NIRF imaging technology. Furthermore, this new cell labeling and tracking technology had minimal effect on cartilage formation in vivo.

DNA amplification in neutral liposomes for safe and efficient gene delivery.

In general, traditional gene carriers contain strong cationic charges to efficiently load anionic genes, but this cationic character also leads to destabilization of plasma membranes and causes severe cytotoxicity. Here, we developed a PCR-based nanofactory as a safe gene delivery system. A few template plasmid DNA can be amplified by PCR inside liposomes about 200 nm in diameter, and the quantity of loaded genes highly increased by more than 8.8-fold. The liposome membrane was composed of neutral lipids free from cationic charges. Consequently, this system is nontoxic, unlike other traditional cationic gene carriers. Intense red fluorescent protein (RFP) expression in CHO-K1 cells showed that the amplified genes could be successfully transfected to cells. Animal experiments with the luciferase gene also showed in vivo gene expression by our system without toxicity. We think that this PCR-based nanofactory system can overcome the toxicity problem that is the critical limitation of current gene delivery to clinical application.

Cell labeling and tracking method without distorted signals by phagocytosis of macrophages.

Cell labeling and tracking are important processes in understanding biologic mechanisms and the therapeutic effect of inoculated cells in vivo. Numerous attempts have been made to label and track inoculated cells in vivo; however, these methods have limitations as a result of their biological effects, including secondary phagocytosis of macrophages and genetic modification. Here, we investigated a new cell labeling and tracking strategy based on metabolic glycoengineering and bioorthogonal click chemistry. We first treated cells with tetra-acetylated N-azidoacetyl-D-mannosamine to generate unnatural sialic acids with azide groups on the surface of the target cells. The azide-labeled cells were then transplanted to mouse liver, and dibenzyl cyclooctyne-conjugated Cy5 (DBCO-Cy5) was intravenously injected into mice to chemically bind with the azide groups on the surface of the target cells in vivo for target cell visualization. Unnatural sialic acids with azide groups could be artificially induced on the surface of target cells by glycoengineering. We then tracked the azide groups on the surface of the cells by DBCO-Cy5 in vivo using bioorthogonal click chemistry. Importantly, labeling efficacy was enhanced and false signals by phagocytosis of macrophages were reduced. This strategy will be highly useful for cell labeling and tracking.

Chemical tumor-targeting of nanoparticles based on metabolic glycoengineering and click chemistry.

Tumor-targeting strategies for nanoparticles have been predominantly based on optimization of physical properties or conjugation with biological ligands. However, their tumor-targeting abilities remain limited and insufficient. Furthermore, traditional biological binding molecules have intrinsic limitations originating from the limited amount of cellular receptors and the heterogeneity of tumor cells. Our two-step in vivo tumor-targeting strategy for nanoparticles is based on metabolic glycoengineering and click chemistry. First, an intravenous injection of precursor-loaded glycol chitosan nanoparticles generates azide groups on tumor tissue specifically by the enhanced permeation and retention (EPR) effect followed by metabolic glycoengineering. These 'receptor-like' chemical groups then enhance the tumor-targeting ability of drug-containing nanoparticles by copper-free click chemistry in vivo during a second intravenous injection. The advantage of this protocol over traditional binding molecules is that there are significantly more binding molecules on the surface of most tumor cells regardless of cell type. The subsequent enhanced tumor-targeting ability can significantly enhance the cancer therapeutic efficacy in animal studies.

Tumor-homing glycol chitosan-based optical/PET dual imaging nanoprobe for cancer diagnosis.

Imaging techniques including computed tomography, magnetic resonance imaging, and positron emission tomography (PET) offer many potential benefits to diagnosis and treatment of cancers. Each method has its own strong and weak points. Therefore, multimodal imaging techniques have been highlighted as an alternative method for overcoming the limitations of each respective imaging method. In this study, we fabricated PET/optical activatable imaging probe based on glycol chitosan nanoparticles (CNPs) for multimodal imaging. To prepare the dual PET/optical probes based on CNPs, both (64)Cu radiolabeled DOTA complex and activatable matrix metalloproteinase (MMP)-sensitive peptide were chemically conjugated onto azide-functionalized CNPs via bio-orthogonal click chemistry, which was a reaction between azide group and dibenzyl cyclooctyne. The PET/optical activatable imaging probes were visualized by PET and optical imaging system. Biodistribution of probes and activity of MMP were successfully measured in tumor-bearing mice.

Biocompatible glycol chitosan-coated gold nanoparticles for tumor-targeting CT imaging.

PURPOSE: The application of gold nanoparticles (AuNPs) in biomedical field was limited due to the low stability in the biological condition. Herein, to enhance stability and tumor targeting ability of AuNPs, their surface was modified with biocompatible glycol chitosan (GC) and the in vivo biodistribution of GC coated AuNPs (GC-AuNPs) were studied through computed tomography (CT). METHODS: Polymer-coated gold nanoparticles were produced using GC as a reducing agent and a stabilizer. Their feasibility in biomedical application was explored through CT in tumor-bearing mice. RESULTS: Stability of gold nanoparticles increased in the physiological condition due to the GC coating layer on the surface. Tomographic images of tumor were successfully obtained in the tumor-xenografted animal model when the GC-AuNPs were used as a CT contrast agent. The tumor targeting property of the gold nanoparticles was due to the properties of GC because GC-AuNPs were accumulated in the tumor, while most of heparin-coated nanoparticles were found in the liver and spleen. CONCLUSIONS: The polymer properties on the surface played an important role in the behavior of gold nanoparticles in the biological condition and the enhanced stability and tumor targeting property of nanoparticles were inherited from GC on the surface.

Non-invasive optical imaging of cathepsin B with activatable fluorogenic nanoprobes in various metastatic models.

An increasing number of treatments of metastases rely on diagnostics and imaging these days. The facts that the activity of cathepsin B (CB) is markedly linked to the metastatic process and that CB is found highly expressed in the pericellular regions in this process make CB an attractive target for diagnosing metastases. We have developed a CB-sensitive nanoprobe (CB-CNP) consisting of self-quenched CB-sensitive fluorogenic peptide probes conjugated onto the surface of tumor-targeting glycol chitosan nanoparticles (CNPs). The freshly prepared CB-CNP formed a spherical nanoparticle structure (280 nm in diameter) and the fluorescence intensity of CB-CNP was strongly quenched in physiological condition. However, self-quenched CB-CNP boosted strong fluorescence signals in the presence of CB, not of cathepsin l or cathepsin d, due to the CB-specific cleavage of self-quenched peptide probes. Importantly, the intravenously injected CB-CNP demonstrated the potential to discriminate metastases in vivo in three metastatic mouse models, including 4T1-luc2 liver metastases, RFP-B16F10 lung metastases and HT1080 peritoneal metastases. Indeed, Western blot analysis confirmed that the CB expression of metastases had increased compared to normal organ in these metastatic mouse models. CB-CNPs may be useful for depicting metastases through non-invasive CB molecular imaging.