Nanoemulsion-based mucosal adjuvant induces apoptosis in human epithelial cells.

Nanoemulsions (NEs) are adjuvants that enhance antigen penetration of the nasal mucosa, increase cellular uptake of antigens by both epithelial and dendritic cells, and promote the migration of antigen-loaded dendritic cells to regional lymph nodes within 24-h of vaccine administration. The objective of this study was to elucidate cell death caused by W805EC NE and identify caspases and genes associated with death pathways. Consistent with this aim, we show that exposure of human epithelial cells (EC), both RPMI 2650 and FaDu, to NE results in the activation of caspases (1, 3/7, 6, 8, and 9) and the expression of genes involved in apoptotic as well as authophagy and necrosis pathways. Interestingly, the NE activates caspase 8 which promotes "immunogenic apoptosis". The rescue assay was employed to investigate the fate of RPMI 2650 cells treated with W805EC NE. After four-hour treatment with as little as 0.03% of NE no cells were rescued at 72h. Remarkably, immediately after four-hour treatment, the cells morphologically resembled untreated cells and most of the cells were alive. Altogether, these results suggest that NE induces death of human ECs through multiple pathways. Epithelial cell death caused by W805EC may have further implications on antigen uptake, processing, and presentation by DC's.

Distinct pathways of humoral and cellular immunity induced with the mucosal administration of a nanoemulsion adjuvant.

Nasal administration of an oil-in-water nanoemulsion (NE) adjuvant W805EC produces potent systemic and mucosal, Th-1- and Th-17-balanced cellular responses. However, its molecular mechanism of action has not been fully characterized and is of particular interest because NE does not contain specific ligands for innate immune receptors. In these studies, we demonstrate that W805EC NE adjuvant activates innate immunity, induces specific gene transcription, and modulates NF-κB activity via TLR2 and TLR4 by a mechanism that appears to be distinct from typical TLR agonists. Nasal immunization with NE-based vaccine showed that the TLR2, TLR4, and MyD88 pathways and IL-12 and IL-12Rß1 expression are not required for an Ab response, but they are essential for the induction of balanced Th-1 polarization and Th-17 cellular immunity. NE adjuvant induces MHC class II, CD80, and CD86 costimulatory molecule expression and dendritic cell maturation. Further, upon immunization with NE, adjuvant mice deficient in the CD86 receptor had normal Ab responses but significantly reduced Th-1 cellular responses, whereas animals deficient in both CD80 and CD86 or lacking CD40 failed to produce either humoral or cellular immunity. Overall, our data show that intranasal administration of Ag with NE induces TLR2 and TLR4 activation along with a MyD88-independent Ab response and a MyD88-dependent Th-1 and Th-17 cell-mediated immune response. These findings suggest that the unique properties of NE adjuvant may offer novel opportunities for understanding previously unrecognized mechanisms of immune activation important for generating effective mucosal and systemic immune responses.

Design and in vitro validation of multivalent dendrimer methotrexates as a folate-targeting anticancer therapeutic.

Design of cancer-targeting nanotherapeutics relies on a pair of two functionally orthogonal molecules, one serving as a cancer cell-specific targeting ligand, and the other as a therapeutic cytotoxic agent. The present study investigates the validity of an alternative simplified strategy where a dual-acting molecule which bears both targeting and cytotoxic activity is conjugated to the nanoparticle as cancer-targeting nanotherapeutics. Herein, we demonstrate that methotrexate is applicable for this dual-acting strategy due to its reasonable affinity to folic acid receptor (FAR) as a tumor biomarker, and cytotoxic inhibitory activity of cytosolic dihydrofolate reductase. This article describes design of new methotrexate-conjugated poly(amidoamine) (PAMAM) dendrimers, each carrying multiple copies of methotrexate attached through a stable amide linker. We evaluated their dual biological activities by performing surface plasmon resonance spectroscopy, a cell-free enzyme assay and cell-based experiments in FAR-overexpressing cells. This study identifies the combination of an optimal linker framework and multivalency as the two key design elements that contribute to achieving potent dual activity.

Polyplex exposure inhibits cell cycle, increases inflammatory response, and can cause protein expression without cell division.

We sought to evaluate the relationship between cell division and protein expression when using commercial poly(ethylenimine) (PEI)-based polyplexes. The membrane dye PKH26 was used to assess cell division, and cyan fluorescent protein (CFP) was used to monitor protein expression. When analyzed at the whole population level, a greater number of cells divided than expressed protein, regardless of the level of protein expression observed, giving apparent consistency with the hypothesis that protein expression requires cells to pass through mitosis in order for the transgene to overcome the nuclear membrane. However, when the polyplex-exposed population was evaluated for the amount of division in the protein-expressing subpopulation, it was observed that substantial amounts of expression had occurred in the absence of division. Indeed, in HeLa S3 cells, this represented the majority of expressing cells. Of interest, the doubling time for both cell lines was slowed by ~2-fold upon exposure to polyplexes. This change was not altered by the origin of the plasmid DNA (pDNA) transgene promoter (cytomegalovirus (CMV) or elongation factor-1 alpha (EF1α)). Gene expression arrays in polyplex-exposed HeLa S3 cells showed upregulation of cell cycle arrest genes and downregulation of genes related to mitosis. Chemokine, interleukin, and toll-like receptor genes were also upregulated, suggesting activation of proinflammatory pathways. In summary, we find evidence that a cell division-independent expression pathway exists, and that polyplex exposure slows cell division and increases inflammatory response.

Nanoemulsion nasal adjuvant W805EC induces dendritic cell engulfment of antigen-primed epithelial cells.

Nanoemulsions are adjuvants that enhance antigen penetration in the nasal mucosa, increase cellular uptake of antigens by both epithelial dendritic cells, and promote migration of antigen-loaded dendritic cells to regional lymph nodes within a day of vaccine administration. The objective of this study was to determine whether the W(80)5EC nanoemulsion adjuvant enhances immune response not only by direct uptake of antigen by dendritic cells, but also indirectly, by phagocytosis of antigen-primed, apoptotic, epithelial cells. Consistent with this, we show that exposure of both epithelial cells (TC-1s) and dendritic cells (JAWS II or bone marrow derived dendritic cells (BMDCs)) to nanoemulsion exhibited augmented antigen uptake in cell culture. TC-1 cells subsequently underwent G(2)/M cell cycle arrest and apoptosis, and when co-cultured with JAWS II or BMDCs were rapidly engulfed by the dendritic cells, which responded by up-regulating dendritic cell maturation marker CD86. Altogether these results suggest that the effectiveness of nanoemulsions as adjuvants stems, at least in part, from the engulfment of antigen-loaded epithelial cells, leading to enhanced antigen processing and a strong and balanced mucosal and systemic immune response.

The facile synthesis of multifunctional PAMAM dendrimer conjugates through copper-free click chemistry.

The facile conjugation of three azido modified functionalities, namely a therapeutic drug (methotrexate), a targeting moiety (folic acid), and an imaging agent (fluorescein) with a G5 PAMAM dendrimer scaffold with cyclooctyne molecules at the surface through copper-free click chemistry is reported. Mono-, di-, and tri-functional PAMAM dendrimer conjugates can be obtained via combinatorial mixing of different azido modified functionalities simultaneously or sequentially with the dendrimer platform. Preliminary flow cytometry results indicate that the folic acid targeted nanoparticles are efficiently binding with KB cells.

Targeting the efficacy of a dendrimer-based nanotherapeutic in heterogeneous xenograft tumors in vivo.

Our earlier studies have shown the in vitro and in vivo targeting of a generation 5 (G5) dendrimer-based multifunctional conjugate that contained folic acid (FA) as the targeting agent and methotrexate (MTX) as the chemotherapeutic drug. To clinically apply the synthesized G5-FA-MTX nanotherapeutic, it is important that the anticancer conjugate elicits cytotoxicity specifically and consistently. Toward this objective, we evaluated the large-scale synthesis of a G5-FA-MTX conjugate (Lot # 123-34) for its cytotoxic potential and specificity in vitro and in vivo. The cytotoxicity and specificity were tested by using a coculture assay in which FA receptor-expressing and nonexpressing cells (KB and SK-BR-3 cells, respectively) were cultured together and preferential killing was examined. The in-vitro data were compared with the in-vivo data obtained from a heterogeneous xenograft tumor model. The animal model of the artificial heterogeneous xenograft tumor showed that the nanotherapeutic was preferentially cytotoxic to KB cells.

RGD dendron bodies; synthetic avidity agents with defined and potentially interchangeable effector sites that can substitute for antibodies.

Poly(amidoamine) (PAMAM) dendrons were synthesized with c(RGDyK) peptide on the surface to create a scaffold for cellular targeting and multivalent binding. Binary dendron-RGD conjugates were synthesized with a single Alexa Fluor 488, biotin, methotrexate drug molecule, or additional functionalized dendron at the focal point. The targeted dendron platform was shown to specifically target αvß3 integrin expressing human umbilical vein endothelial cells (HUVEC) and human glioblastoma cells (U87MG) in Vitro via flow cytometry. Specific targeting of the dendron-RGD platform was further confirmed by confocal microscopy. Biological activity of the targeted drug conjugate was confirmed via XTT assay. The orthogonal reaction chemistry used at the dendron focal point gives a precise 1:1 ratio of the attachment of multiple functionalities to a small-molecular-weight, chemically stable, high avidity molecule. These studies serve as a framework to selectively combine biologically relevant functions with enhanced specific binding activity to substitute for antibodies in many diagnostic and therapeutic applications.

Targeted gadolinium-loaded dendrimer nanoparticles for tumor-specific magnetic resonance contrast enhancement.

A target-specific MRI contrast agent for tumor cells expressing high affinity folate receptor was synthesized using generation five (G5) ofpolyamidoamine (PAMAM) dendrimer. Surface modified dendrimer was functionalized for targeting with folic acid (FA) and the remaining terminal primary amines of the dendrimer were conjugated with the bifunctional NCS-DOTA chelator that forms stable complexes with gadolinium (Gd III). Dendrimer-DOTA conjugates were then complexed with GdCl3 followed by ICP-OES as well as MRI measurement of their longitudinal relaxivity (T1 s(-1) mM(-1)) of water. In xenograft tumors established in immunodeficient (SCID) mice with KB human epithelial cancer cells expressing folate receptor (FAR), the 3D MRI results showed specific and statistically significant signal enhancement in tumors generated with targeted Gd(III)-DOTA-G5-FA compared with signal generated by non-targeted Gd(III)-DOTA-G5 contrast nanoparticle. The targeted dendrimer contrast nanoparticles infiltrated tumor and were retained in tumor cells up to 48 hours post-injection of targeted contrast nanoparticle. The presence of folic acid on the dendrimer resulted in specific delivery of the nanoparticle to tissues and xenograft tumor cells expressing folate receptor in vivo. We present the specificity of the dendrimer nanoparticles for targeted cancer imaging with the prolonged clearance time compared with the current clinically approved gadodiamide (Omniscan) contrast agent. Potential application of this approach may include determination of the folate receptor status of tumors and monitoring of drug therapy.

Preclinical antitumor efficacy evaluation of dendrimer-based methotrexate conjugates.

Our previous studies have demonstrated the in-vitro and in-vivo targeting of a generation-5 (G5) dendrimer-based multifunctional conjugate, which used folic acid (FA) as the targeting agent and methotrexate (MTX) as the chemotherapeutic drug. For the synthesized G5-FA-MTX nanodevice conjugate to be clinically applicable as a cancer therapeutic drug, it is important that the compound elicits cytotoxicity specifically and consistently. The aim of this work was to evaluate four independently synthesized batches of G5-FA-MTX conjugates for their cytotoxic potential and specificity. For determination of specificity, we have used a unique 'coculture' assay in which FA receptor-positive and FA receptor-negative cells were cultured together and have examined the preferential killing of the former. The results of our study show the batch-to-batch consistency and specificity of the G5-FA-MTX nanodevice in the preferential killing of FA receptor-positive cells. The coculture assay shows the consistency of the four different G5-FA-MTX conjugate lots in the specific killing of targeted cells. Further in-vivo studies are, however, necessary to prove the clinical potential of this targeted therapeutic nanodevice.

HER2 specific tumor targeting with dendrimer conjugated anti-HER2 mAb.

In the present study, we report the synthesis and human growth factor receptor-2 (HER2) specific tumor targeting properties of a dendrimer conjugated to anti-HER2 mAb (monoclonal antibody) conjugate. The polyamidoamine (PAMAM) dendrimer generation five (G5) was labeled with alexaFluor 488 and conjugated to anti-HER2 mAb. The binding and internalization of the antibody-conjugated dendrimer to HER2-expressing cells was evaluated by flow cytometry and confocal microscopy. Uniquely, the conjugate demonstrated cellular uptake and internalization in HER2-expressing cells as compared to free antibody. The time course of internalization and blocking experiments with free antibody suggest that the rapid and efficient cellular internalization of the dendrimer-antibody conjugate was achieved without alterations in specificity of targeting. Animal studies demonstrated that the conjugate targets HER2-expressing tumors.

Targeted drug delivery with dendrimers: comparison of the release kinetics of covalently conjugated drug and non-covalent drug inclusion complex.

Dendrimers have unique characteristics including monodispersity and modifiable surface functionality, along with highly defined size and structure. This makes these polymers attractive candidates as carriers in drug delivery applications. Drug delivery can be achieved by coupling a drug to polymer through one of two approaches. Hydrophobic drugs can be complexed within the hydrophobic dendrimer interior to make them water-soluble or drugs can be covalently coupled onto the surface of the dendrimer. Using both methods we compared the efficacy of generation 5 PAMAM dendrimers in the targeted drug delivery of methotrexate coupled to the polymer. The amine-terminated dendrimers bind to negatively charged membranes of cells in a non-specific manner and can cause toxicity in vitro and in vivo. To reduce toxicity and to increase aqueous solubility, modifications were made to the surface hydroxyl groups of the dendrimers. For targeted drug delivery, the dendrimer was modified to have a neutral terminal functionality for use with surface-conjugated folic acid as the targeting agent. The complexation of methotrexate within a dendrimer changes the water insoluble drug into a stable and readily water-soluble compound. When this dendrimer complexed drug, however, was placed in a solution of phosphate buffered saline, the methotrexate was immediately released and displayed diffusion characteristics identical to free methotrexate. Covalently coupled methotrexate dendrimer conjugates were stable under identical conditions in water and buffered saline. Cytotoxicity tests showed that methotrexate as the dendrimer inclusion complex had an activity identical to the free drug in vitro. In contrast, folic acid targeted dendrimer with covalently conjugated methotrexate specifically killed receptor-expressing cells by intracellular delivery of the drug through receptor-mediated endocytosis. This study demonstrates that while drug as a dendrimer inclusion complex is readily released and active in vitro, covalently conjugated drug to dendrimer is better suited for specifically targeted drug delivery.

Nanoparticle targeting of anticancer drug improves therapeutic response in animal model of human epithelial cancer.

Prior studies suggested that nanoparticle drug delivery might improve the therapeutic response to anticancer drugs and allow the simultaneous monitoring of drug uptake by tumors. We employed modified PAMAM dendritic polymers <5 nm in diameter as carriers. Acetylated dendrimers were conjugated to folic acid as a targeting agent and then coupled to either methotrexate or tritium and either fluorescein or 6-carboxytetramethylrhodamine. These conjugates were injected i.v. into immunodeficient mice bearing human KB tumors that overexpress the folic acid receptor. In contrast to nontargeted polymer, folate-conjugated nanoparticles concentrated in the tumor and liver tissue over 4 days after administration. The tumor tissue localization of the folate-targeted polymer could be attenuated by prior i.v. injection of free folic acid. Confocal microscopy confirmed the internalization of the drug conjugates into the tumor cells. Targeting methotrexate increased its antitumor activity and markedly decreased its toxicity, allowing therapeutic responses not possible with a free drug.

Targeting and inhibition of cell growth by an engineered dendritic nanodevice.

The cellular uptake and cytotoxicity of an engineered multifunctional dendritic nanodevice containing folic acid (FA) as the targeting molecule, methotrexate (MTX) as the chemotherapeutic drug, and fluorescein (FI) as the detecting agent were studied in vitro. FI and FA were conjugated to the generation 5 poly(amidoamine) (G5) dendrimer carrier through a thiourea and amide linkage and MTX was conjugated through an ester linkage to the carrier to generate the trifunctional dendritic device, G5-FI-FA-MTX. This trifunctional dendrimer-drug conjugate bound to FA receptor-expressing KB cells in a dose-dependent and saturable manner. Confocal microscopic analysis demonstrated cellular internalization of the conjugate. G5-FI-FA-MTX induced a time- and dose-dependent inhibition of cell growth in KB cells. The targeted dendrimer conjugates G5-FI-FA-MTX and G5-FA-MTX inhibited cell growth in KB cells, whereas the nontargeted G5-MTX failed to induce growth inhibition. These studies show the potential of G5-FI-FA-MTX or G5-FA-MTX for targeting and growth suppression of tumor cells that overexpress FA-receptors.

Nasal mucosal gene expression in patients with allergic rhinitis with and without nasal polyps.

BACKGROUND: Nasal polyps are a common problem that is difficult to diagnose and treat, in part because the cause of nasal polyposis is unknown. Although information on the pathogenesis of polyposis is lacking, there are reports suggesting that a genetic predisposition underlies this disorder. OBJECTIVE: We sought to better understand the basis of nasal polyposis associated with allergic rhinitis. We hypothesize that the expression of unique genes is associated with the nasal polyposis phenotype. METHODS: We examined 12000 human genes transcribed in the nasal mucosa of patients with allergic rhinitis with and without nasal polyps. Biopsy specimens of the mucosa of patients with and without polyps were obtained after the patients refrained from the use of topical or systemic steroid therapy for 2 weeks. RESULTS: Thirty-four genes were differentially expressed between the patient groups, including those for inflammatory molecules and putative growth factors. The greatest differential expression identified by the array analysis was for a group of genes associated with neoplasia, including mammaglobin, a gene transcribed 12-fold higher in patients with polyps compared with control patients with rhinitis alone. Quantitative RT-PCR confirmed this differential expression and documented that the number of mammaglobin mRNA copies is actually 64-fold greater in tissues of patients with polyps versus control patients. The specificity of mammaglobin protein expression was evaluated by means of immunohistochemistry, which showed specific staining in nasal polyp mucosal goblet cells only in patients with polyps. CONCLUSION: These data suggest that nasal polyposis involves deregulated cell growth, using gene activation in some ways similar to a neoplasm. In addition, mammaglobin, a gene of unknown function associated with breast neoplasia, might be related to polyp growth.

Development of immune response that protects mice from viral pneumonitis after a single intranasal immunization with influenza A virus and nanoemulsion.

Nanoemulsion, a water-in-oil formulation stabilized by small amounts of surfactant, is non-toxic to mucous membranes and produces biocidal activity against enveloped viruses. We evaluated nanoemulsion as an adjuvant for mucosal influenza vaccines. Mice (C3H/HeNHsd strain) were vaccinated intranasally with 5 x 10(5) plaque forming units (pfu) of influenza A virus (Ann Arbor/6/60 strain) and a nanoemulsion mixture. The mice were challenged on day 21 after immunization with an intranasal lethal dose of 2 x 10(5) pfu of virus. Animals vaccinated with the influenza A/nanoemulsion mixture were completely protected against infection, while animals vaccinated with either formaldehyde-killed virus or nanoemulsion alone developed viral pneumonitis and died by day 6 after the challenge. Mice vaccinated with virus/nanoemulsion mixture had rapid cytokine responses followed by high levels of specific anti-influenza immunoglobulin G (IgG) and immunoglobulin A (IgA) antibodies. Specificity of the immune response was confirmed by assessment of the proliferation and cytokine production in splenocytes. This paper demonstrates that nanoemulsion can be employed as a non-toxic mucosal adjuvant for influenza virus vaccine.