Receptor mediated glycotargeting

Emodin nanocapsules inhibit acute pancreatitis by regulating lipid metabolic reprogramming in macrophage polarization

BACKGROUND

Emodin is a chemical compound found in traditional Chinese herbs. It possesses anti-inflammatory and many other pharmacological effects. Our previous study showed that emodin significantly alleviates the inflammation effect of severe acute pancreatitis (SAP). However, its poor solubility, high toxicity and limited pancreas retention time hinder its clinical application.

PURPOSE

We aimed to prepare emodin nanocapsules with improved bioavailability to achieve the controlled release of emodin by targeting macrophages. Further, the mechanism of mannose-conjugated chitosan-coated lipid nanocapsules loaded with emodin (M-CS-E-LNC) in the treatment of SAP was explored.

METHODS

M-CS-E-LNC were prepared by the phase inversion method with slight modification. The expression of inflammation mediators and the anti-inflammation efficacy of M-CS-E-LNC were examined by ELISA, IHC and IF in macrophage cells and LPS-induced SAP mice. IVIS spectrum imaging and HPLC were applied to explore the controlled release of M-CS-E-LNC in the pancreas. LC-MS/MS was performed for lipidomics analysis of macrophages. Moreover, a vector-based short hairpin RNA (shRNA) method was used to silence CTP1 gene expression in macrophage cells.

RESULTS

The levels of inflammatory mediators in macrophages were markedly decreased after treatment with M-CS-E-LNC. The same anti-inflammation effects were detected in SAP mouse through the analysis of serum levels of amylase, TNF-α and IL-6. Importantly, M-CS-E-LNC allowed the emodin to selectively accumulate at pancreas and gastrointestinal tissues, thus exhibiting a targeted release. Mechanistically, the M-CS-E-LNC treatment group showed up-regulated expression of the carnitine palmitoyltransferase 1 (CPT1) protein which promoted intracellular long-chain fatty acid transport, thereby promoting the M2 phenotype polarization of macrophages.

CONCLUSION

M-CS-E-LNC exhibited significantly improved bioavailability and water solubility, which translated to greater therapeutic effects on macrophage polarization. Our findings also demonstrate, for the first time, that CPT1 may be a new therapeutic target for SAP treatment.

Preliminary efficacy of [90Y]DOTA-biotin-avidin radiotherapy against non-muscle invasive bladder cancer

PURPOSE

Bladder cancer represents 3% of all new cancer diagnoses per year. We propose intravesical radionuclide therapy using the β-emitter ⁹⁰Y linked to DOTA-biotin-avidin ([⁹⁰Y]DBA) to deliver short-range radiation against non-muscle invasive bladder cancer (NMIBC).

MATERIAL AND METHODS

Image-guided biodistribution of intravesical DBA was investigated in an animal model by radiolabeling DBA with the ⁶⁸Ga and dynamic microPET imaging following intravesical infusion of [⁶⁸Ga]DBA for up to 4 h and post-necropsy γ-counting of organs. The antitumor activity of [⁹⁰Y]DBA was investigated using an orthotopic MB49 murine bladder cancer model. Mice were injected with luciferase-expressing MB49 cells and treated via intravesical administration with 9.2 MBq of [⁹⁰Y]DBA or unlabeled DBA 3 days after the tumor implantation. Bioluminescence imaging was conducted after tumor implantation to monitor the bladder tumor growth. In addition, we investigated the effects of [⁹⁰Y]DBA radiation on urothelial histology with immunohistochemistry analysis of bladder morphology.

RESULTS

Our results demonstrated that DBA is contained in the bladder for up to 4 h after intravesical infusion. A single dose of [⁹⁰Y]DBA radiation treatment significantly reduced growth of MB49 bladder carcinoma. Attaching ⁹⁰Y-DOTA-biotin to avidin prevents its re-absorption into the blood and distribution throughout the rest of the body. Furthermore, immunohistochemistry demonstrated that [⁹⁰Y]DBA radiation treatment did not cause short-term damage to urothelium at day 10, which appeared similar to the normal urothelium of healthy mice.

CONCLUSION

Our data demonstrates the potential of intravesical [⁹⁰Y]DBA as a treatment for non-muscle invasive bladder cancer.

Thermoresponsive Glycopolypeptide Containing Block Copolymers, Particle Formation, and Lectin Interaction

Amphiphilic block copolymers with a thermoresponsive poly(N-isopropylacrylamide) block and a glycopeptide block are synthesized and particle formation as well as interaction of the glyco-corona with lectins is investigated. The synthetic route comprises the preparation of block copolymers by N-carboxyanhydride polymerization and subsequent deprotection to obtain pH- and thermoresponsive poly(l-glutamic acid)-b-poly(N-isopropylacrylamide) (pGA-b-pNIPAM), which is then further modified with different amino sugars by a versatile coupling method with 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholin-4-ium chloride (DMT-MM). The glycosylated pGA-b-pNIPAM block copolymers are investigated with regard to cloud point temperatures (T_cp ), particle size, and stability. The morphology of the particles is visualized using cryo-SEM. Zeta potential measurements are indicating that the saccharide moieties are located on the surface of the particles. This assumption is further substantiated by quantitative lectin interaction assays with nonaggregated and aggregated glycosylated pGA-b-pNIPAM. The interaction of the model lectin ConA with the block copolymers is independent of the degree of substitution in the nonaggregated state at room temperature. However, at 37 °C, when particles of pGA-b-pNIPAM are present, the interaction becomes stronger with increasing degree of substitution. This interaction with lectins can be used for targeting saccharide-modified particles in drug delivery.

Trehalose Conjugates of Silybin as Prodrugs for Targeting Toxic Aβ Aggregates

Alzheimer's disease (AD) is linked to the abnormal accumulation of amyloid β peptide (Aβ) aggregates in the brain. Silybin B, a natural compound extracted from milk thistle (Silybum marianum), has been shown to significantly inhibit Aβ aggregation in vitro and to exert neuroprotective properties in vivo. However, further explorations of silybin B's clinical potential are currently limited by three main factors: (a) poor solubility, (b) instability in blood serum, and (c) only partial knowledge of silybin's mechanism of action. Here, we address these three limitations. We demonstrate that conjugation of a trehalose moiety to silybin significantly increases both water solubility and stability in blood serum without significantly compromising its antiaggregation properties. Furthermore, using a combination of biophysical techniques with different spatial resolution, that is, TEM, ThT fluorescence, CD, and NMR spectroscopy, we profile the interactions of the trehalose conjugate with both Aβ monomers and oligomers and evidence that silybin may shield the "toxic" surfaces formed by the N-terminal and central hydrophobic regions of Aβ. Finally, comparative analysis with silybin A, a less active diastereoisomer of silybin B, revealed how even subtle differences in chemical structure may entail different effects on amyloid inhibition. The resulting insight on the mechanism of action of silybins as aggregation inhibitors is anticipated to facilitate the future investigation of silybin's therapeutic potential.

Preparation of dendritic carboranyl glycoconjugates as potential anticancer therapeutics

A series of carborane-appended glycoconjugates containing three and six glucose and galactose moieties have been synthesized via Cu(i)-catalyzed azide–alkyne [3 + 2] click cycloaddition reaction. The carboranyl glycoconjugates containing three glucose and galactose moieties were found to be partially water soluble whereas increasing the number to six made them completely water soluble. The evaluation of cytotoxicities and IC₅₀ values of newly synthesized carboranyl glycoconjugates was carried out using two cancerous cell lines (MCF-7 breast cancer cells and A431 skin cancer cells) and one normal cell line (HaCaT skin epidermal cell line). All carboranyl glycoconjugates showed higher cytotoxicities towards cancerous cell lines than the normal cell line. Carboranyl glycoconjugates containing three glucose and galactose moieties (compounds 15 and 17) were found to be more cytotoxic than the glycoconjugates containing six glucose and galactose moieties (compounds 19 and 21). Moreover, administration of 100 μM concentrations of compounds 15 and 17 inhibited up to 83% of MCF-7 breast cancer cells and up to 79% A431 skin cancer cells. However, administration of similar concentrations of carboranyl glycoconjugates could inhibit only up to 35–45% of HaCaT normal epidermal cells. Thus, due to the higher cytotoxicities of dendritic carboranyl glycoconjugates towards cancer cells over healthy cells, they could potentially be useful for bimodal treatment of cancer such as chemotherapy agents and boron neutron capture therapy (BNCT) agents as well.

o-Carborane-appended glycoconjugates containing multiple glucose and galactose moieties are found to be more cytotoxic towards cancer cells than normal cells.

Silibinin phosphodiester glyco-conjugates: Synthesis, redox behaviour and biological investigations

New silibinin phosphodiester glyco-conjugates were synthesized by efficient phosphoramidite chemistry and were fully characterized by 2D-NMR. A wide-ranging study focused on the determination of their pKa and E° values as well as on their radical scavenging activities by different assays (DPPH, ABTS⁺ and HRSA) was conducted. The new glyco-conjugates are more water-soluble than silibinin, and their radical scavenging activities are higher than those of silibinin. The conjugation therefore improves both the water solubilities and antioxidant activities of the flavonolignan moieties. The serum stability was evaluated under physiological conditions, and the glyco-conjugates degraded with half-lives of 40-70 h, making them useful in pro-drug approaches. We started by treating androgen-dependent prostate cancer (PCa) LNCaP cells and then expanded our studies to androgen-independent PCa PC3 and DU145 cells. In most cases, the new derivatives significantly reduced both total and live cell numbers, albeit at different levels. Anti-HIV activities were evaluated and the glucosamine-phosphate silibinin derivative showed higher activity (IC₅₀ = 73 μM) than silibinin.

Critical physicochemical and biological attributes of nanoemulsions for pulmonary delivery of rifampicin by nebulization technique in tuberculosis treatment

The study investigated aerosolization, pulmonary inhalation, intracellular trafficking potential in macrophages and pharmacokinetics profiles of rifampicin-oleic acid first-generation nanoemulsion and its respective chitosan- and chitosan-folate conjugate-decorated second and third-generation nanoemulsions, delivered via nebulization technique. The nanoemulsions were prepared by conjugate synthesis and spontaneous emulsification techniques. They were subjected to physicochemical, drug release, aerosolization, inhalation, cell culture and pharmacokinetics analysis. The nanoemulsions had average droplet sizes of 40-60 nm, with narrow polydispersity indices. They exhibited desirable pH, surface tension, viscosity, refractive index, density and viscosity attributes for pulmonary rifampicin administration. All nanoemulsions demonstrated more than 95% aerosol output and inhalation efficiency greater than 75%. The aerosol output, aerosolized and inhaled fine particle fractions were primarily governed by the size and surface tension of nanoemulsions in an inverse relationship. The nanoemulsions were found to be safe with third-generation nanoemulsion exhibiting higher cell internalization potential, reduced plasma drug concentration, and higher lung drug content.

Targeted and ultrasound-triggered cancer cell injury using perfluorocarbon emulsion-loaded liposomes endowed with cancer cell-targeting and fusogenic capabilities

This study investigated the targeting and ultrasound-triggered injury of cancer cells using anticancer drug-free liposomes that contained an emulsion of perfluoropentane (ePFC5) and were co-modified with avidin as a targeting ligand for cancer cells and the hemagglutinating virus of Japan (HVJ) envelope to promote liposome fusion with the cells. These liposomes are designated as ePFC5-loaded avidin/HVJ liposomes. ePFC5-loaded liposomes were sensitized to ultrasound irradiation. Liposomes modified with avidin alone (avidin liposomes) showed binding to MCF-7 human breast cancer cells, and liposomes modified with HVJ envelope alone (HVJ liposomes) were found to fuse with MCF-7 cells. The irradiation of MCF-7 cells with 1 MHz ultrasound (30s, 1.2 W/cm(2), duty ratio 30%) combined with ePFC5-loaded avidin/HVJ liposomes resulted in a decrease in cell viability at 1h after irradiation to 43% of that of controls without ultrasound irradiation or liposomes. The cell viability was lower than that of cells treated with ultrasound irradiation with ePFC5-loaded avidin liposomes or ePFC5-loaded HVJ liposomes. This indicates that co-modification of liposome with avidin and HVJ envelope could enhance ultrasound-induced cell injury in the presence of ePFC5-loaded liposomes.

Development of 4-sulfated N-acetyl galactosamine anchored chitosan nanoparticles: A dual strategy for effective management of Leishmaniasis

The present investigation reports the modification of chitosan nanoparticles with a ligand 4-sulfated N-acetyl galactosamine (4-SO4GalNAc) for efficient chemotherapy in leishmaniasis (SCNPs) by using dual strategy of targeting. These (SCNPs) were loaded with amphotericin B (AmB) for specific delivery to infected macrophages. Developed AmB loaded SCNPs (AmB-SCNPs) had mean particle size of 333 ± 7 nm, and showed negative zeta potential (-13.9 ± 0.016 mV). Flow cytometric analysis revealed enhanced uptake of AmB-SCNPs in J774A.1, when compared to AmB loaded unmodified chitosan NPs (AmB-CNPs). AmB-SCNPs provide significantly higher localization of AmB in liver and spleen as compared to AmB-CNPs after i.v. administration. The study stipulates that 4-SO4GalNAc assures of targeting, resident macrophages. Highly significant anti-leishmanial activity (P<0.05 compared with AmB-CNPs) was observed with AmB-SCNPs, causing 75.30 ± 3.76% inhibition of splenic parasitic burdens. AmB-CNPs and plain AmB caused only 63.89 ± 3.44% and 47.56 ± 2.37% parasite inhibition, respectively, in Leishmania-infected hamsters (P<0.01 for AmB-SCNPs versus plain AmB and AmB-CNPs versus plain AmB).

Targeted sonocatalytic cancer cell injury using avidin-conjugated titanium dioxide nanoparticles

In this study, we applied sonodynamic therapy to cancer cells based on the delivery of titanium dioxide (TiO2) nanoparticles (NPs) modified with avidin protein, which preferentially discriminated cancerous cells from healthy cells. Subsequently, hydroxyl radicals were generated from the TiO2 NPs after activation by external ultrasound irradiation (TiO2/US treatment). Although 30% of the normal breast cells (human mammary epithelial cells) exhibited the uptake of avidin-modified TiO2 NPs, over 80% of the breast cancer cells (MCF-7) exhibited the uptake of avidin-TiO2 NPs. Next the effect of the TiO2/US treatment on MCF-7 cell growth was examined for up to 96 h after 1-MHz ultrasound was applied (0.1 W/cm(2), 30 s) to cells that incorporated the TiO2 NPs. No apparent cell injury was observed until 24h after the treatment, but the viable cell concentration declined to 68% compared with the control at 96 h.

Effect of ultrasound irradiation on bacterial internalization and bacteria-mediated gene transfer to cancer cells

The present study demonstrates that ultrasound irradiation can facilitate bacteria-mediated gene delivery (bactofection). Escherichia coli modified with avidin were employed as a vehicle for delivery of the green fluorescent protein (GFP) gene, a model heterologous gene, into the breast cancer cell line MCF-7. Avidin-mediated binding of E. coli to MCF-7 cells enhanced the internalization of E. coli by approximately 17%, irrespective of the use of ultrasound irradiation. Furthermore, the use of ultrasound irradiation increased the internalization by approximately 5%, irrespective of the presence of avidin on the E. coli cell surface. The percentages of GFP-expressing MCF-7 cells at 24h after bactofection were below 0.5% and 2% for the case with only avidin-modification of E. coli cell surface and only ultrasound irradiation, respectively. However, combining avidin modification with the ultrasound treatment increased this value to 8%. Thus, the use of avidin-modified bacteria in conjunction with ultrasound irradiation has potential as an effective strategy for tumor-targeted bactofection.

Trans-resveratrol loaded chitosan nanoparticles modified with biotin and avidin to target hepatic carcinoma

Conventional liver targeted system focuses on delivering drugs to liver, bringing toxicity on hepatic normal tissues. The purpose of this study is to construct a new system capable of specially targeting to hepatic carcinoma instead of the whole liver. Based on the fact that nanoparticles (NPs) bound with either biotin or avidin tend to accumulate in tumors and avidin-attached reagents were quickly eliminated from blood circulation and assembled in liver, trans-resveratrol loaded chitosan nanoparticles (CS-NPs), CS-NPs with the surface modified either by biotin (B-CS-NPs) or by both biotin and avidin (A-B-CS-NPs) were prepared and their physiochemical properties were investigated. The in vitro release profiles of the three NPs all conformed to bioexponential equation. Pharmacokinetic experiment indicated that A-B-CS-NPs rapidly assembled in liver after injection, with the highest liver targeting index of 2.70, while the modification of biotin attenuated the liver targeting ability of NPs. Inhibitory study on HepG2 cells declared that compared to trans-resveratrol solution and CS-NPs, both B-CS-NPs and A-B-CS-NPs significantly improved the anticancer activity. When incubated with HepG2 cells at high concentration for longer time, A-B-CS-NPs exhibited superior cytotoxicity than B-CS-NPs. This study exclaims that A-B-CS-NPs may be a potent drug delivery vector specially targeting to hepatic carcinoma.

Targeting siglecs--a novel pharmacological strategy for immuno- and glycotherapy

The immune system must be tightly held in check to avoid bystander tissue damage as well as autoreactivity caused by overwhelming immune reactions. A novel family of immunoregulatory, carbohydrate-binding receptors, the Siglecs (sialic acid binding immunoglobulin-like lectins), has received particular attention in light of their capacity to mediate cell death, anti-proliferative effects and to regulate a variety of cellular activities. Siglec receptors are mainly expressed on leukocytes in a cell type-specific and differentiation-dependent manner. Siglecs might potentially be exploited as targets of novel immune- and glycotherapeutics for cell-directed therapies in autoimmune and allergic diseases, as well as in haematologic malignancies. Here we present novel insights on structural and functional characteristics, expression patterns and evolutionary aspects of Siglecs and their ligands. Pharmacological strategies using Siglec agonistic cross-linking therapeutics, such as monoclonal or engineered antibodies, intravenous immunoglobulin (IVIG), or glycomimetics are discussed. Modulation of immune responses by targeting Siglecs using agonistic or antagonistic therapeutics may have important clinical implications and may pave the way for novel pharmacological avenues for the treatment of autoimmune and allergic diseases or for tumor immunotherapy.

Mannosylated solid lipid nanoparticles as vectors for site-specific delivery of an anti-cancer drug

The purpose of the present study was to investigate the tumor targeting potential of surface tailored solid lipid nanoparticles (SLNs) loaded with an anti-cancer drug doxorubicin HCl (DOX). DOX encapsulating SLNs were prepared, characterized and further mannosylated. The developed formulations were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), particle size/polydispersity index and zeta-potential analysis. The formulations were evaluated for in vitro drug release and hemolytic toxicity. The ex vivo cytotoxicity and cellular uptake studies were performed on A549 cell lines. In vivo studies were conducted to determine pharmacokinetics, tissue distribution pattern and nephrotoxic/hepatotoxic effect of mannosylated SLNs. In vitro, the formulations exhibited a biphasic pattern characterized by initial rapid release of the drug followed by rather slow and prolonged release. Further, the in vitro studies depicted mannose-conjugated SLNs to be least hemolytic and suitable for sustained drug delivery. Mannosylated SLNs were most cytotoxic and were preferably taken up A549 tumor cells as evaluated against uncoated SLNs and plain DOX. Pharmacokinetic studies revealed improved bioavailability, half life and mean residence time of DOX upon mannose conjugation. The biodistribution pattern exhibited that mannosylated SLNs were able to deliver a higher concentration of DOX in the tumor mass. They were also proficient to circumvent damage to renal as well as hepatic tissues. It may therefore be interpreted that mannosylated SLNs are capable to ferry bioactives selectively and specifically to the tumor sites with the interception of minimal side effects, thereby suggesting their potential application in cancer chemotherapy.

Recent developments in carbohydrate-decorated targeted drug/gene delivery

Targeted delivery of a drug or gene to its site of action has clear therapeutic advantages by maximizing its therapeutic efficiency and minimizing its systemic toxicity. Generally, targeted drug or gene delivery is performed by loading a macromolecular carrier with an appropriate drug or gene, and by targeting the drug/gene carrier to specific cell or tissue with the help of specific targeting ligand. The emergence of glycobiology, glycotechnology, and glycomics and their continual adaptation by pharmaceutical scientists have opened exciting avenue of medicinal applications of carbohydrates. Among them, the biocompatibility and specific receptor recognition ability confer the ability of carbohydrates as potential targeting ligands for targeted drug and gene delivery applications. This review summarizes recent progress of carbohydrate-decorated targeted drug/gene delivery applications.

Radiolabelled153Sm-chelates of glycoconjugates: multivalence and topology effects on the targeting of the asialoglycoprotein receptor

In this paper we report and discuss the biodistribution studies with Wistar rats of a series of153Sm(III)-glycoconjugates, based on DO3A and DO2A(cis) scaffolds (DO3A=1,4,7-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecane; DO2A(cis) = 1,4-bis(carboxymethyl)-1,4,7,10-tetraazacyclododecane). The effects of changing the sugar type (galactose, lactose and glucose), valency (mono and divalent) and topology on the targeting ability of the liver asialoglycoprotein receptor (ASGPR) are evaluated. Divalent glycoconjugates with different topologies were generated by a pendant glycodendrimeric (generation 1) architecture on a DO3A scaffold and by a linear DO2A(cis)-bis derivative. The results show that the galactose conjugates are more target efficient than the lactose analogues, while the glucose conjugates have no liver targeting ability. Divalent galactose conjugates are more efficiently targeted to the liver than the monovalent ones, while the dendrimeric topology of DO3A-Gal2has higher targeting efficiency than that of the DO2A(cis)-Gal2.

Drug targeting to the colon with lectins and neoglycoconjugates

Targeting of drugs to specific sites of action provides several advantages over non-targeted drugs. These include the prevention of side effects of drugs on healthy tissues and enhancement of drug uptake by targeted cells. This review will cover traditional approaches of colon drug targeting as well as the use of lectins and neoglycoconjugates for the targeted delivery. Direct and reverse targeting strategies, potential molecular targets and targeting moieties for colon drug delivery, targeted drug delivery systems (DDS) for colon delivery, anticancer DDS targeted to colon cancer are examined. Directions of future development are discussed.

The lectin-cell interaction and its implications to intestinal lectin-mediated drug delivery

Based on the fact that oligosaccharides encode biological information, the biorecognition between lectinised drug delivery systems and glycosylated structures in the intestine can be exploited for improved peroral therapy. Basic research revealed that some lectins can mediate mucoadhesion, cytoadhesion, and cytoinvasion of drugs. Entering the vesicular pathway by receptor mediated endocytosis, part of the conjugated drug is accumulated within the lysosomes. Additionally, part of the drug is supposed to be transported across the epithelium. Moreover, factors probably adversely influencing feasibility of the concept such as toxicity, immunogenicity, and intestinal stability of plant lectins are discussed. As exemplified by lectin-grafted prodrug and carrier systems, this strategy is expected to improve absorption and probably bioavailability of poorly absorbable drugs, peptides and proteins as well as therapeutic DNA.

Chemoenzymatic Synthesis of Narrow-Polydispersity Glycopolymers: Poly(6-O-vinyladipoyl-d-glucopyranose)

The glycomonomer 6-O-vinyladipoyl-D-glucopyranose was prepared via lipase catalyzed transesterification of divinyladipate with alpha-D-glucopyranose in dry acetonitrile and acetone. The desired 6-O regioisomer was obtained in good yield, and its structure was confirmed by correlation NMR spectroscopy. Controlled radical polymerization of the unprotected monomer was performed in protic media using both xanthate and dithiocarbamate as chain transfer agents to give poly(6-O-vinyladipoyl-D-glucopyranose) with Mn of 17 and 19 kDa (SEC) respectively and a polydispersity as low as 1.10. To the best of our knowledge, this is the first example of a narrow-polydispersity, poly(vinyl ester)-like glycopolymer.