Upconversion nanoparticle-assisted single-molecule assay for detecting circulating antigens of aggressive prostate cancer.

Sensitive and quantitative detection of molecular biomarkers is crucial for the early diagnosis of diseases like metabolic syndrome and cancer. Here we present a single-molecule sandwich immunoassay by imaging the number of single nanoparticles to diagnose aggressive prostate cancer. Our assay employed the photo-stable upconversion nanoparticles (UCNPs) as labels to detect the four types of circulating antigens in blood circulation, including glypican-1 (GPC-1), leptin, osteopontin (OPN), and vascular endothelial growth factor (VEGF), as their serum concentrations indicate aggressive prostate cancer. Under a wide-field microscope, a single UCNP doped with thousands of lanthanide ions can emit sufficiently bright anti-Stokes' luminescence to become quantitatively detectable. By counting every single streptavidin-functionalized UCNP which specifically labeled on each sandwich immune complex across multiple fields of views, we achieved the Limit of Detection (LOD) of 0.0123 ng/ml, 0.2711 ng/ml, 0.1238 ng/ml, and 0.0158 ng/ml for GPC-1, leptin, OPN and VEGF, respectively. The serum circulating level of GPC-1, leptin, OPN, and VEGF in a mixture of 10 healthy normal human serum was 25.17 ng/ml, 18.04 ng/ml, 11.34 ng/ml, and 1.55 ng/ml, which was within the assay dynamic detection range for each analyte. Moreover, a 20% increase of GPC-1 and OPN was observed by spiking the normal human serum with recombinant antigens to confirm the accuracy of the assay. We observed no cross-reactivity among the four biomarker analytes, which eliminates the false positives and enhances the detection accuracy. The developed single upconversion nanoparticle-assisted single-molecule assay suggests its potential in clinical usage for prostate cancer detection by monitoring tiny concentration differences in a panel of serum biomarkers.

Spray-Dried Particles of Nitric Oxide-Modified Glutathione for the Treatment of Chronic Lung Infection.

Antibiotic resistance in pathogenic bacteria has emerged as a big challenge to human and animal health and significant economy loss worldwide. Development of novel strategies to tackle antibiotic resistance is of the utmost priority. In this study, we combined glutathione (GSH), a master antioxidant in all mammalian cells, and nitric oxide, a proven biofilm-dispersing agent, to produce GSNO. The resazurin biofilm viability assay, crystal violet biofilm assay, and confocal microscopy techniques showed that GSNO disrupted biofilms of both P. aeruginosa PAO1 and multidrug resistant A. baumaunii (MRAB 015069) more efficiently than GSH alone. In addition, GSNO showed a higher reduction in biofilm viability and biomass when combined with antibiotics. This combination treatment also inhibited A. baumaunii (MRAB 015069) growth and facilitated human foreskin fibroblast (HFF-1) confluence and growth simultaneously. A potentially inhalable GSNO powder with reasonable aerosol performance and antibiofilm activity was produced by spray drying. This combination shows promise as a novel formulation for treating pulmonary bacterial infections.

Exonuclease III-Assisted Upconversion Resonance Energy Transfer in a Wash-Free Suspension DNA Assay.

Sensitivity is the key in optical detection of low-abundant analytes, such as circulating RNA or DNA. The enzyme Exonuclease III (Exo III) is a useful tool in this regard; its ability to recycle target DNA molecules results in markedly improved detection sensitivity. Lower limits of detection may be further achieved if the detection background of autofluorescence can be removed. Here we report an ultrasensitive and specific method to quantify trace amounts of DNA analytes in a wash-free suspension assay. In the presence of target DNA, the Exo III recycles the target DNA by selectively digesting the dye-tagged sequence-matched probe DNA strand only, so that the amount of free dye removed from the probe DNA is proportional to the number of target DNAs. Remaining intact probe DNAs are then bound onto upconversion nanoparticles (energy donor), which allows for upconversion luminescence resonance energy transfer (LRET) that can be used to quantify the difference between the free dye and tagged dye (energy acceptor). This scheme simply avoids both autofluorescence under infrared excitation and many tedious washing steps, as the free dye molecules are physically located away from the nanoparticle surface, and as such they remain "dark" in suspension. Compared to alternative approaches requiring enzyme-assisted amplification on the nanoparticle surface, introduction of probe DNAs onto nanoparticles only after DNA hybridization and signal amplification steps effectively avoids steric hindrance. Via this approach, we have achieved a detection limit of 15 pM in LRET assays of human immunodeficiency viral DNA.

Late Acute and Chronic Graft-versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation.

Several distinct graft-versus-host disease (GVHD)-related syndromes have been defined by the National Institutes of Health Consensus Conference. We enrolled a prospective cohort of 911 hematopoietic cell transplantation (HCT) recipients at 13 centers between March 2011 and May 2014 to evaluate 4 GVHD syndromes: late acute GVHD (aGVHD), chronic GVHD (cGVHD), bronchiolitis obliterans syndrome, and cutaneous sclerosis. The median age at HCT was 53.7 years. The majority of patients received a peripheral blood stem cell transplant (81%) following nonmyeloablative or reduced-intensity conditioning (55%). Pediatric age group and use of bone marrow and umbilical cord blood grafts were underrepresented in our cohort (≤11%). The cumulative incidence of late aGVHD (late onset and recurrent) was 10% at a median of 5.5 months post-HCT, that of cGVHD was 47% at a median of 7.4 months, that of bronchiolitis obliterans was 3% at a median of 12.2 months, and that of cutaneous sclerosis was 8% at a median onset of 14.0 months. Late aGVHD and bronchiolitis obliterans had particularly high nonrelapse mortality of 23% and 32%, respectively, by 2 years after diagnosis. The probability of late aGVHD- and cGVHD-free, relapse-free survival was 38% at 1 year post-HCT and 26% at 2 years post-HCT. This multicenter prospective study confirms the high rate of late aGVHD and cGVHD syndromes and supports the need for continuous close monitoring and development of more effective GVHD treatment strategies to improve HCT success.

A Rationally Optimized Nanoparticle System for the Delivery of RNA Interference Therapeutics into Pancreatic Tumors in Vivo.

Pancreatic cancer is a devastating disease with a dismal prognosis. Short-interfering RNA (siRNA)-based therapeutics hold promise for the treatment of cancer. However, development of efficient and safe delivery vehicles for siRNA remains a challenge. Here, we describe the synthesis and physicochemical characterization of star polymers (star 1, star 2, star 3) using reversible addition-fragmentation chain transfer polymerization (RAFT) for the delivery of siRNA to pancreatic cancer cells. These star polymers were designed to contain different lengths of cationic poly(dimethylaminoethyl methacrylate) (PDMAEMA) side-arms and varied amounts of poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA). We showed that star-POEGMA polymers could readily self-assemble with siRNA to form nanoparticles. The star-POEGMA polymers were nontoxic to normal cells and delivered siRNA with high efficiency to pancreatic cancer cells to silence a gene (TUBB3/ßIII-tubulin) which is currently undruggable using chemical agents, and is involved in regulating tumor growth and metastases. Notably, systemic administration of star-POEGMA-siRNA resulted in high accumulation of siRNA to orthotopic pancreatic tumors in mice and silenced ßIII-tubulin expression by 80% at the gene and protein levels in pancreatic tumors. Together, these novel findings provide strong rationale for the use of star-POEGMA polymers as delivery vehicles for siRNA to pancreatic tumors.

The use of nanoparticles to deliver nitric oxide to hepatic stellate cells for treating liver fibrosis and portal hypertension.

Polymeric nanoparticles are designed to transport and deliver nitric oxide (NO) into hepatic stellate cells (HSCs) for the potential treatment of both liver fibrosis and portal hypertension. The nanoparticles, incorporating NO donor molecules (S-nitrosoglutathione compound), are designed for liver delivery, minimizing systemic delivery of NO. The nanoparticles are decorated with vitamin A to specifically target HSCs. We demonstrate, using in vitro and in vivo experiments, that the targeted nanoparticles are taken up specifically by rat primary HSCs and the human HSC cell line accumulating in the liver. When nanoparticles, coated with vitamin A, release NO in liver cells, we find inhibition of collagen I and α-smooth muscle actin (α-SMA), fibrogenic genes associated with activated HSCs expression in primary rat liver and human activated HSCs without any obvious cytotoxic effects. Finally, NO-releasing nanoparticles targeted with vitamin A not only attenuate endothelin-1 (ET-1) which elicites HSC contraction but also acutely alleviates haemodynamic disorders in bile duct-ligated-induced portal hypertension evidenced by decreasing portal pressure (≈20%) and unchanging mean arterial pressure. This study clearly shows, for the first time, the potential for HSC targeted nanoparticle delivery of NO as a treatment for liver diseases with proven efficacy for alleviating both liver fibrosis and portal hypertension.

Cyclosporine in combination with mycophenolate mofetil versus methotrexate for graft versus host disease prevention in myeloablative HLA-identical sibling donor allogeneic hematopoietic cell transplantation.

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality in allogeneic hematopoietic cell transplantation (HCT) despite current prophylaxis. Methotrexate (MTX) with a calcineurin inhibitor (CNI) is the current standard, however, has several toxicities. Mycophenolate mofetil (MMF) is frequently used in reduced-intensity HCT, but data in myeloablative transplants is limited. We thus retrospectively identified 241 patients who underwent myeloablative HCT from an HLA-identical sibling donor; 174 patients received cyclosporine (CSA) + MMF and 67 received CSA+MTX. Patients receiving MMF + CSA had rapid neutrophil (median 11 vs. 19 days with MTX+CSA), and platelet recovery (median 19 vs. 25 days), lower incidence of severe mucositis by OMAS (19% vs. 53%), and shorter length of hospital stay (median 25 vs. 36 days) (P < 0.001 for all comparisons). There were no significant differences in incidence of grade 2-4 (MMF+CSA 37% vs. MTX+CSA 39%) or 3-4 acute GVHD (17% vs. 12%), chronic GVHD (46% vs. 56%), relapse (28% vs. 27%), non-relapse mortality (20% vs. 27%), or overall survival (47% vs. 44%) (P = NS for all). However, in multivariable analysis, the use of MMF+CSA was associated with an increased risk of severe grade 3-4 acute GVHD (HR 2.92, 95% CI 1.2-7.15, P = 0.019). There were no differences between the two regimens in multivariable analyses for other survival outcomes. This analysis demonstrates that the use of MMF in myeloablative sibling donor transplantation is well tolerated. However, there may be an increased risk of severe GVHD with MMF+CSA compared to MTX+CSA. Further studies evaluating optimal dosing strategies are needed.

Synergistic effect of major histocompatibility complex class I-related chain a and human leukocyte antigen-DPB1 mismatches in association with acute graft-versus-host disease after unrelated donor hematopoietic stem cell transplantation.

The clinical relevance of mismatches at the MHC class I-related chain A (MICA) in hematopoietic stem cell transplantation (HSCT) remains unclear. We investigated the association of MICA donor/recipient mismatch and whether there is an interaction between these and HLA-DPB1 mismatch on clinical outcomes after unrelated donor HSCT. Our study included 227 patients who underwent unrelated donor allogeneic HSCT at our institution between 2000 and 2010. Among these, 177 (78%) received HSCT from a 10/10 HLA-matched donor. MICA genotyping was performed using commercially available kits. In univariable analysis, the risk of grade II to IV acute graft-versus-host disease (GVHD) was greater for patients with MICA mismatch (hazard ratio [HR], 1.73; P = .02) than for those with HLA-DPB1 mismatch (HR, 1.62; P = .07). When MICA and HLA-DPB1 were assessed simultaneously, patients mismatched at both loci had the greatest risk (HR, 2.51; P < .01) and those mismatched at only 1 locus had somewhat greater risk (HR, 1.53; P = .12) than patients matched at both loci; this remained significant in multivariable analysis. The 100-day incidence was 66%, 45%, and 31%, respectively (P = .03). Results were similar for grade III and IV acute GVHD, with 100-day incidence 34%, 16%, and 8% (P = .01). These results are clinically pertinent to donor selection strategies and indicate that patients with mismatch at both MICA and HLA-DPB1 are at increased risk for acute GVHD.

Peripheral blood progenitor cell mobilization for autologous and allogeneic hematopoietic cell transplantation: guidelines from the American Society for Blood and Marrow Transplantation.

Peripheral blood progenitor cell mobilization practices vary significantly among institutions. Effective mobilization regimens include growth factor alone, chemotherapy and growth factor combined, and, more recently, incorporation of plerixafor with either approach. Many institutions have developed algorithms to improve stem cell mobilization success rates and cost-effectiveness. However, an optimal stem cell mobilization regimen has not been defined. Practical guidelines are needed to address important clinical questions, including which growth factor is optimal, what chemotherapy and dose is most effective, and when to initiate leukapheresis. We present recommendations, based on a comprehensive review of the literature, from the American Society of Blood and Marrow Transplantation.

Dextran-based doxorubicin nanocarriers with improved tumor penetration.

Drug delivery systems with improved tumor penetration are valuable assets as anticancer agents. A dextran-based nanocarrier system with aldehyde functionalities capable of forming an acid labile linkage with the chemotherapy drug doxorubicin was developed. Aldehyde dextran nanocarriers (ald-dex-dox) demonstrated efficacy as delivery vehicles with an IC50 of ∼300 nM against two-dimensional (2D) SK-N-BE(2) monolayers. Confocal imaging showed that the ald-dex-dox nanocarriers were rapidly internalized by SK-N-BE(2) cells. Fluorescence lifetime imaging microscopy (FLIM) analysis indicated that ald-dex-dox particles were internalized as intact complexes with the majority of the doxorubicin released from the particle four hours post uptake. Accumulation of the ald-dex-dox particles was significantly enhanced by ∼30% in the absence of glucose indicating a role for glucose and its receptors in their endocytosis. However, inhibition of clathrin dependent and independent endocytosis and macropinocytosis as well as membrane cholesterol depletion had no effect on ald-dex-dox particle accumulation. In three-dimensional (3D) SK-N-BE(2) tumor spheroids, which more closely resemble a solid tumor, the ald-dex-dox nanoparticles showed a significant improvement in efficacy over free doxorubicin, as evidenced by decreased spheroid outgrowth. Drug penetration studies in 3D demonstrated the ability of the ald-dex-dox nanocarriers to fully penetrate into a SK-N-BE(2) tumor spheroids, while doxorubicin only penetrates to a maximum distance of 50 µM. The ald-dex-dox nanocarriers represent a promising therapeutic delivery system for the treatment of solid tumors due to their unique enhanced penetration ability combined with their improved efficacy over the parent drug in 3D.

Nanoparticle (star polymer) delivery of nitric oxide effectively negates Pseudomonas aeruginosa biofilm formation.

Biofilms are increasingly recognized as playing a major role in human infectious diseases, as they can form on both living tissues and abiotic surfaces, with serious implications for applications that rely on prolonged exposure to the body such as implantable biomedical devices or catheters. Therefore, there is an urgent need to develop improved therapeutics to effectively eradicate unwanted biofilms. Recently, the biological signaling molecule nitric oxide (NO) was identified as a key regulator of dispersal events in biofilms. In this paper, we report a new class of core cross-linked star polymers designed to store and release nitric oxide, in a controlled way, for the dispersion of biofilms. First, core cross-linked star polymers were prepared by reversible addition-fragmentation chain transfer polymerization (RAFT) via an arm first approach. Poly(oligoethylene methoxy acrylate) chains were synthesized by RAFT polymerization, and then chain extended in the presence of 2-vinyl-4,4-dimethyl-5-oxazolone monomer (VDM) with N,N-methylenebis(acrylamide) employed as a cross-linker to yield functional core cross-linked star polymers. Spermine was successfully attached to the star core by reaction with VDM. Finally, the secondary amine groups were reacted with NO gas to yield NO-core cross-linked star polymers. The core cross-linked star polymers were found to release NO in a controlled, slow delivery in bacterial cultures showing great efficacy in preventing both cell attachment and biofilm formation in Pseudomonas aeruginosa over time via a nontoxic mechanism, confining bacterial growth to the suspended liquid.

Biomimetic polymers responsive to a biological signaling molecule: nitric oxide triggered reversible self-assembly of single macromolecular chains into nanoparticles.

Novel nitric oxide (NO) responsive monomers (NAPMA and APUEMA) containing o-phenylenediamine functional groups have been polymerized to form NO-responsive macromolecular chains as truly biomimetic polymers. Upon exposure to NO--a ubiquitous cellular signaling molecule--the NAPMA- and APUEMA-labeled thermoresponsive copolymers exhibited substantial changes in solubility, clearly characterized by tuneable LCST behavior, thereby inducing self-assembly into nanoparticulate structures. Moreover, the NO-triggered self-assembly process in combination with environmentally sensitive fluorescence dyes could be employed to detect and image endogenous NO.

Defining incidence, risk factors, and impact on survival of central line-associated blood stream infections following hematopoietic cell transplantation in acute myeloid leukemia and myelodysplastic syndrome.

Central line-associated blood stream infections (CLABSI) commonly complicate the care of patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) after allogeneic stem cell transplantation (HCT). We developed a modified CLABSI (MCLABSI) definition that attempts to exclude pathogens usually acquired because of disruption of mucosal barriers during the vulnerable neutropenic period following HCT that are generally included under the original definition (OCLABSI). We conducted a retrospective study of all AML and MDS patients undergoing HCT between August 2009 and December 2011 at the Cleveland Clinic (N = 73), identifying both OCLABSI and MCLABSI incidence. The median age at transplantation was 52 years (range, 16 to 70); 34 had a high (≥3) HCT comorbidity index (HCT-CI); 34 received bone marrow (BM), 24 received peripheral stem cells (PSC), and 15 received umbilical cord blood cells (UCB). Among these 73 patients, 23 (31.5%) developed OCLABSI, of whom 16 (69.6%) died, and 8 (11%) developed MCLABSI, of whom 7 (87.5%) died. OCLABSI was diagnosed a median of 9 days from HCT: 5 days (range, 2 to 12) for UCB and 78 days (range, 7 to 211) for BM/PSC (P < .001). MCLABSI occurred a median of 12 days from HCT, with similar earlier UCB and later BM/PSC diagnosis (P = .030). Risk factors for OCLABSI in univariate analysis included CBC (P < .001), human leukocyte antigen (HLA)-mismatch (P = .005), low CD34(+) count (P = .007), low total nucleated cell dose (P = .016), and non-Caucasian race (P = .017). Risk factors for OCLABSI in multivariable analysis were UCB (P < .001) and high HCT-CI (P = .002). There was a significant increase in mortality for both OCLABSI (hazard ratio, 7.14; CI, 3.31 to 15.37; P < .001) and MCLABSI (hazard ratio, 6.44; CI, 2.28 to 18.18; P < .001). CLABSI is common and associated with high mortality in AML and MDS patients undergoing HCT, especially in UCB recipients and those with high HCT-CI. We propose the MCLABSI definition to replace the OCLABSI definition, given its greater precision for identifying preventable infection in HCT patients.

Effective delivery of siRNA into cancer cells and tumors using well-defined biodegradable cationic star polymers.

Cancer is one of the most common causes of death worldwide. Two types of cancer that have high mortality rates are pancreatic and lung cancer. Despite improvements in treatment strategies, resistance to chemotherapy and the presence of metastases are common. Therefore, novel therapies which target and silence genes involved in regulating these processes are required. Short-interfering RNA (siRNA) holds great promise as a therapeutic to silence disease-causing genes. However, siRNA requires a delivery vehicle to enter the cell to allow it to silence its target gene. Herein, we report on the design and synthesis of cationic star polymers as novel delivery vehicles for siRNA to silence genes in pancreatic and lung cancer cells. Dimethylaminoethyl methacrylate (DMAEMA) was polymerized via reversible addition-fragmentation transfer polymerization (RAFT) and then chain extended in the presence of both cross-linkers N,N-bis(acryloyl)cistamine and DMAEMA, yielding biodegradable well-defined star polymers. The star polymers were characterized by transmission electron microscopy, dynamic light scattering, ζ potential, and gel permeation chromatography. Importantly, the star polymers were able to self-assemble with siRNA and form small uniform nanoparticle complexes. Moreover, the ratios of star polymer required to complex siRNA were nontoxic in both pancreatic and lung cancer cells. Treatment with star polymer-siRNA complexes resulted in uptake of siRNA into both cell lines and a significant decrease in target gene mRNA and protein levels. In addition, delivery of clinically relevant amounts of siRNA complexed to the star polymer were able to silence target gene expression by 50% in an in vivo tumor setting. Collectively, these results provide the first evidence of well-defined small cationic star polymers to deliver active siRNA to both pancreatic and lung cancer cells and may be a valuable tool to inhibit key genes involved in promoting chemotherapy drug resistance and metastases.

Folate conjugation to polymeric micelles via boronic acid ester to deliver platinum drugs to ovarian cancer cell lines.

In this study, a novel technique was used for the reversible attachment of folic acid on the surface of polymeric micelles for a tumor-specific drug delivery system. The reversible conjugation is based on the interaction between phenylboronic acid (PBA) and dopamine to form a borate ester. The conjugation is fast and efficient and in vitro experiments via confocal fluorescent microscopy show that the linker is stable in for several hours. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize two various sized water-soluble block copolymer of oligoethylene glycol methylether methacylate and methyl acrylic acid (POEGMEMA(35)-b-PMAA(200) and POEGMEMA(26)-b-PMAA(90)). The platinum drug, oxoplatin, was then subsequently attached to the polymer via ester formation leading to platinum loading of 12 wt % as determined by TGA. The platinum-induced amphiphilic block copolymers that consequently led to the formation of micelles of sizes 150 and 20 nm in an aqueous environment with the longer PMAA block forming larger micelles. The small micelles were in addition cross-linked using 1,8-diaminooctane to further stabilize their structure. The targeting ability of folate conjugated polymeric micelles was investigated against two types of tumor cell lines: A549 (-FR) and OVCAR-3 (+FR). The cell line growth inhibitory efficacy of material synthesized was evaluated by using SRB method. The results revealed that folate conjugated micelles showed higher activity in FR + OVCAR-3 cells but not in FR - A549 cells. Similar results were obtained for both small and large micelles without the conjugation of folate. Comparing large and small micelles it can be observed that larger micelles are more efficient, which has been attributed to the lower stability of the smaller micelles. Micelle stabilization via cross-linking could indeed increase the toxicity of the drug carrier.

Risk factors for 30-day hospital readmission following myeloablative allogeneic hematopoietic cell transplantation (allo-HCT).

Patient readmission within 30 days from discharge has been perceived by the Centers for Medicare and Medical Services as an indicator of poor healthcare quality for specific high-cost medical conditions. Patients who undergo allogeneic hematopoietic cell transplantation (allo-HCT) are often being readmitted. Our study identified the risk factors for 30-day readmission among 618 adult recipients of myeloablative allo-HCT from 1990 to 2009. Two hundred forty-two (39%) of 618 patients (median age = 42 years [range: 18-66]) were readmitted a median of 10 days (range: 1-30) from their hospital discharge. Median duration of readmission was 8 days (range: 0-103). Infections (n = 68), fever with or without identified source of infection (n = 63), gastrointestinal complications (n = 44), graft-versus-host disease (GVHD) (n = 38), and other reasons (n = 29) accounted for 28%, 26%, 18%, 16%, and 12% of readmissions, respectively. During their index admission, patients who were subsequently readmitted had more documented infections (P < .001), higher hematopoietic cell transplantation comorbidity index (HCT-CI) (P < .01), total body irridiation (TBI)-based conditioning (P < .001), unrelated donor (P < .001), and peripheral stem cell (P = .014) transplantation. In multivariable analysis, HCT-CI (odds ratio [OR] = 1.78; 95% confidence interval [CI], 1.25-2.52), TBI-based preparative regimen (OR = 2.63; 95% CI, 1.67-4.13), and infection during admission for allo-HSCT (OR = 2.00; 95% CI, 1.37-2.92) predicted 30-day readmission. Thirty-day readmission itself was an independent predictor of all-cause mortality (hazard ratio [HR](Adj) = 1.66; 95% CI, 1.36-2.10). Our data emphasize the importance of a risk-standardized approach to 30-day hospital readmission if it is used as a quality-of-care metric for bone marrow transplantation.

Generation of a Listeria vaccine strain by enhanced caspase-1 activation.

The immunostimulatory properties conferred by vaccine adjuvants require caspase-1 for processing of IL-1ß and IL-18. Caspase-1 is activated in response to a breach of the cytosolic compartment by microbes and the process is initiated by intracellular pattern recognition receptors within inflammasomes. Listeria monocytogenes is detected in the cytosol by the NLRC4, NLRP3 and AIM2 inflammasomes. NLRC4 is activated by flagellin, and L. monocytogenes evades NLRC4 by repressing flagellin expression. We generated an L. monocytogenes strain that was forced to express flagellin in the host cell cytosol. This strain hyperactivated caspase-1 and was preferentially cleared via NLRC4 detection in an IL-1ß/IL-18 independent manner. We also created a strain of L. monocytogenes with forced expression of another NLRC4 agonist, PrgJ, from the Type III secretion system of Salmonella typhimurium. Forced expression of flagellin or PrgJ resulted in attenuation, yet both strains conferred protective immunity in mice against lethal challenge with L. monocytogenes. This work is the first demonstration of specific targeting of the caspase-1 activation pathway to generate a safe and potent L. monocytogenes-based vaccine. Moreover, the attenuated strains with embedded flagellin or PrgJ adjuvants represent attractive vectors for vaccines aimed at eliciting T-cell responses.

Functionalizing biodegradable dextran scaffolds using living radical polymerization: new versatile nanoparticles for the delivery of therapeutic molecules.

Conferring biodegradability to nanoparticles is vitally important when nanomedicine applications are being targeted, as this prevents potential problems with bioaccumulation of byproducts after delivery. In this work, dextran has been modified (and rendered hydrophobic) by partial acetalation. A solid state NMR method was first developed to fully characterize the acetalated polymers. In a subsequent synthetic step, RAFT functionality was attached via residual unmodified hydroxyl groups. The RAFT groups were then used in a living free radical polymerization reaction to control the growth of hydrophilic PEG-methacrylate chains, thereby generating amphiphilic comblike polymers. The amphiphilic polymers were then self-assembled in water to form various morphologies, including small vesicles, wormlike rods, and micellar structures, with PEG at the periphery acting as a nonfouling biocompatible polymer layer. The acetalated dextran nanoparticles were designed for potential doxorubicin (DOX) delivery application based on the premise that in the cell compartments (endosome, lysozome) the acetalated dextran would hydrolyze, destroying the nanoparticle structure, releasing the encapsulated DOX. In-vitro studies confirmed minimal cytotoxicity of the (unloaded) nanoparticles, even after 3 days, proving that the hydrolysis products from the acetal groups (methanol and acetone) had no observable cytotoxic effect. An intriguing initial result is reported that in vitro studies of DOX-loaded dextran-nanoparticles (compared to free DOX) revealed an increased differential toxicity toward a cancer cell line when compared to a normal cell line. Efficient accumulation of DOX in a human neuroblastoma cell line (SY-5Y) was confirmed by both confocal microscopy and flow cytometry measurements. Furthermore, the time dependent release of DOX was monitored using fluorescence lifetime imaging microscopy (FLIM) in SY-5Y live cells. FLIM revealed bimodal lifetime distributions, showing the accumulation of both DOX-loaded dextran-nanoparticles and subsequent release of DOX in the living cells. From FLIM data analysis, the amount of DOX released in SY-5Y cells was found to increase from 35% to 55% when the incubation time increased from 3 h to 24 h.

Synthesis of functional core, star polymers via RAFT polymerization for drug delivery applications.

Poly(oligoethylene glycol) methyl ether acrylate was polymerized via reversible addition fragmentation transfer polymerization (RAFT), and then chain extended in the presence of both a cross-linker and vinyl benzaldehyde (VBA), yielding monodisperse star polymers. The presence of aldehyde groups in the core was exploited to attach doxorubicin. The drug loading was controlled by the amount of VBA incorporated (until 28 wt% in drug). The doxorubicin release was studied at pH = 5.5 and 7.4; conditions representative of endosomal and extra cellular environments. In vitro studies revealed that the doxorubicin-conjugated star polymers had a level of cytotoxicity comparable to that found for free doxorubicin. Confocal microscopy and flow cytometry studies confirmed efficient cell uptake of the star polymers.

Predicting hematopoietic stem cell mobilization failure in patients with multiple myeloma: a simple method using day 1 CD34+ cell yield.

Early and reliable prediction of the likelihood of achieving adequate stem cell collection for autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM) would improve collection efficiency, prevent unnecessary aphereses, and permit appropriate treatment alterations. No previous study has reported a threshold CD34+ cell collection quantity on Day 1 or 2 of leukapheresis that could predict successful stem cell collection. We performed a retrospective analysis of all MM patients undergoing first attempt of stem cell collection at our institution from 2001 through 2008. Recursive partitioning analysis was used to identify Day 1 or Day 1+2 CD34+ collection quantity that predicted failure to reach target ≥ 2 × 10(6) CD34+ cells/kg within five days of collection. Totally, 172 patients were included in the analysis. Patients underwent mobilization with G-CSF or G-CSF+ chemotherapy. 23 of 172 patients (13.4%) failed to collect sufficient (≥ 2 × 10(6) CD34+ cells/kg) CD34+ cells after five days of apheresis: 22 of 29 who collected ≤ 0.70 × 10(6) CD34+ cells/kg and 1 of 143 who collected > 0.70 × 10(6) CD34+ cells/kg (75.9% vs. 0.7%, P < 0.001) on Day 1. Collection failure occurred in 23 of 30 patients who collected ≤ 1.54 × 10(6) CD34+ cells/kg and 0 of 142 who collected >1.54 × 10(6) CD34+ cells/kg (76.7% vs. 0%, P < 0.001) on Days 1 + 2. Day 1 CD34+ cell collection quantity identifies patients unlikely to achieve adequate collection for ASCT. Patients who collect ≤ 0.70 × 10(6) CD34+ cells/kg on day 1 could be considered for treatment modifications to improve CD34+ collection, such as early administration of plerixafor or large volume apheresis.