Gold nanoparticles with a monolayer of doxorubicin-conjugated amphiphilic block copolymer for tumor-targeted drug delivery

Gold (Au) nanoparticles (NPs) stabilized with a monolayer of folate-conjugated poly(l-aspartate-doxorubicin)-b-poly(ethylene glycol) copolymer (Au-P(LA-DOX)-b-PEG-OH/FA) was synthesized as a tumor-targeted drug delivery carrier. The Au-P(LA-DOX)-b-PEG-OH/FA NPs consist of an Au core, a hydrophobic poly(l-aspartate-doxorubicin) (P(LA-DOX)) inner shell, and a hydrophilic poly(ethylene glycol) and folate-conjugated poly(ethylene glycol) outer shell (PEG-OH/FA). The anticancer drug, doxorubicin (DOX), was covalently conjugated onto the hydrophobic inner shell by acid-cleavable hydrazone linkage. The DOX loading level was determined to be 17 wt%. The Au-P(LA-DOX)-b-PEG-OH/FA NPs formed stable unimolecular micelles in aqueous solution. The size of the Au-P(LA-DOX)-b-PEG-OH/FA micelles were determined as 24–52 and 10–25 nm by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The conjugated DOX was released from the Au-P(LA-DOX)-b-PEG-OH/FA micelles much more rapidly at pH 5.3 and 6.6 than at pH 7.4, which is a desirable characteristic for tumor-targeted drug delivery. Cellular uptake of the Au-P(LA-DOX)-b-PEG-OH/FA micelles facilitated by the folate-receptor-mediated endocytosis process was higher than that of the micelles without folate. This was consistent with the higher cytotoxicity observed with the Au-P(LA-DOX)-b-PEG-OH/FA micelles against the 4T1 mouse mammary carcinoma cell line. These results suggest that Au-P(LA-DOX)-b-PEG-OH/FA NPs could be used as a carrier with pH-triggered drug releasing properties for tumor-targeted drug delivery.     

The promoter polymorphism -232C/G of the PCK1 gene is associated with type 2 diabetes in a UK-resident South Asian population

Background  

The PCK1 gene, encoding cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C), has previously been implicated as a candidate gene for type 2 diabetes (T2D) susceptibility. Rodent models demonstrate that over-expression of Pck1 can result in T2D development and a single nucleotide polymorphism (SNP) in the promoter region of human PCK1 (-232C/G) has exhibited significant association with the disease in several cohorts. Within the UK-resident South Asian population, T2D is 4 to 6 times more common than in indigenous white Caucasians. Despite this, few studies have reported on the genetic susceptibility to T2D in this ethnic group and none of these has investigated the possible effect of PCK1 variants. We therefore aimed to investigate the association between common variants of the PCK1 gene and T2D in a UK-resident South Asian population of Punjabi ancestry, originating predominantly from the Mirpur area of Azad Kashmir, Pakistan.     

Fn14-TRAIL,a Chimeric Intercellular Signal Exchanger,Attenuates Experimental Autoimmune Encephalomyelitis

Hallmarks of the pathogenesis of autoimmune encephalomyelitis include perivascular infiltration of inflammatory cells into the central nervous system, multifocal demyelination in the brain and spinal cord, and focal neuronal degeneration. Optimal treatment of this complex disease will ultimately call for agents that target the spectrum of underlying pathogenic processes. In the present study, Fn14-TRAIL is introduced as a unique immunotherapeutic fusion protein that is designed to exchange and redirect intercellular signals within inflammatory cell networks, and, in so doing, to impact multiple pathogenic events and yield a net anti-inflammatory effect. In this soluble protein product, a Fn14 receptor component (capable of blocking the pro-inflammatory TWEAK ligand) is fused to a TRAIL ligand (capable of inhibiting activated, pathogenic T cells). Sustained Fn14-TRAIL expression was obtained in vivo using a transposon-based eukaryotic expression vector. Fn14-TRAIL expression effectively prevented chronic, nonremitting, paralytic disease in myelin oligodendrocyte glycoprotein-challenged C57BL/6 mice. Disease suppression in this model was reflected by decreases in the clinical score, disease incidence, nervous tissue inflammation, and Th1, Th2, and Th17 cytokine responses. Significantly, the therapeutic efficacy of Fn14-TRAIL could not be recapitulated simply by administering its component parts (Fn14 and TRAIL) as soluble agents, either alone or in combination. Its functional pleiotropism was manifest in its additional ability to attenuate the enhanced permeability of the blood-brain barrier that typically accompanies autoimmune encephalomyelitis.Despite a steadily expanding set of treatment options for multiple sclerosis (MS), there remains a pressing need for more effective therapeutic agents to address this debilitating autoimmune disorder of the central nervous system (CNS). Although the precise etiology of MS is unknown, key features of its pathogenesis and clinical evolution are emerging.^1,2,3 Among various immune cellular effectors that have been implicated, pathogenic T cells loom large as pivotal drivers of the disease. As a consequence, various therapeutic paths are converging on T effectors as targets, with complementary goals of blocking their activation and re-activation, eliminating them from the larger T-cell reservoir, and interfering with their transit to sites of pathogenesis within the CNS.A complex interplay of positive and negative intercellular signals regulates activation and maintenance of T-cell effector functions. Proteins of the tumor necrosis factor (TNF) superfamily figure prominently in this matrix of signals, bridging various cells of the immune system, as well as to cells of other organ systems. In so doing, TNF superfamily members contribute to both tissue homeostasis and pathogenesis via effects on cell survival and death, cellular differentiation, and inflammation.^4,5 From the standpoint of autoimmune pathogenesis, two especially interesting members of the TNF superfamily are the cell surface ligands TWEAK (TNF-related weak inducer of apoptosis)^6,7 and TRAIL (TNF-related apoptosis-inducing ligand).^8,9,10,11 TWEAK, a TNF superfamily ligand, and its counter-receptor Fn14 (fibroblast growth factor-inducible 14-kDa protein) are expressed in a range of immune and nonimmune cell types. TWEAK, which is expressed on cells such as macrophages, dendritic cells, NK cells, endothelial cells, microglial cells, and astrocytes,^6,12,13 stimulates proliferation of astrocytes and endothelial cells, as well as production of various inflammatory cytokines, chemokines, and adhesion molecules.^{14,15,16,17,18,19} Moreover, the TWEAK:Fn14 signaling axis has pro-inflammatory effects that go beyond promoting cell proliferation and cytokine production, some of which tie into autoimmune pathogenesis. TWEAK, whose endogenous expression is elevated in the CNS during experimental autoimmune encephalitis (EAE), a murine model for MS, increases the permeability of the neurovascular unit,²⁰ contributing in this way to perivascular inflammatory cell infiltration. Moreover, TWEAK has pro-angiogenic activity,²¹ which is of interest given the association between angiogenesis and autoimmune pathogenesis.²² TWEAK increases EAE severity and associated neurodegeneration,^14,23,24 and circulating TWEAK levels are significantly increased in patients with MS and other chronic inflammatory diseases.⁶ The induction of inhibitory anti-TWEAK or Fn14 antibody (Ab) in vivo, via vaccination with the extracellular domains of either TWEAK or Fn14, ameliorates EAE manifestations in rat and mouse models.²⁵TRAIL, a TNF superfamily ligand, binds to several different cognate TNF receptor superfamily receptors, some activating and others decoy. The activating receptors in humans are TRAIL-R1(DR4), TRAIL-R2 (DR5), and osteoprotegrin, whereas in mice, the sole activating receptor is DR5. Virtually all cells of the immune system (including T cells, B cells, natural killer cells, dendritic cells, monocytes, and granulocytes) up-regulate surface TRAIL ligand and/or release soluble TRAIL in response to interferon and other activation signals. TRAIL receptors are primarily expressed on immune cells, such as activated T cells.^8,26 Native TRAIL expression attenuates EAE, as is evident from experiments invoking genetic deletion of TRAIL (in TRAIL^−/− knockout mice) or administration of TRAIL blocking agents [soluble TRAIL receptor (sDR5) or neutralizing anti-TRAIL mAb].^27,28,29 Moreover, embryonic stem cell-derived dendritic cells with enforced co-expression of TRAIL and pathogenic myelin oligodendrocyte glycoprotein (MOG) protein suppress EAE induction.³⁰ Interestingly, soluble TRAIL has emerged as a response marker in MS patients undergoing interferon (IFN)-β therapy,³¹ with those most likely to respond to treatment showing early and sustained soluble TRAIL induction after therapeutic cytokine administration.Based on this intriguing constellation of activities associated with the TWEAK:Fn14 and TRAIL:TRAIL-R signaling axes, which impact immunological responses and inflammatory processes, we have now designed an Fn14-TRAIL fusion protein that bridges them. The Fn14 component of this fusion protein has the capacity to bind and block endogenous TWEAK, whereas the TRAIL ligand component, once anchored to TWEAK-bearing cells via the Fn14 bridge, can direct intercellular inhibitory signals to its cognate receptors on TRAIL receptor-bearing cells, such as activated T cells.Fn14-TRAIL is in essence exchanging TWEAK pro-inflammatory signals into immunoinhibitory TRAIL-driven ones. However, in contrast to another fusion protein that alters intercellular signals, the trans signal converter protein CTLA-4-FasL,^32,33,34,35 Fn14-TRAIL is designed to redirect an exchanged negative signal to third-party (TRAIL receptor-bearing) cells. Furthermore, by virtue of the highly pleiotropic functionality of the TRAIL:TRAIL-R and TWEAK:Fn14 signaling axes, Fn14-TRAIL has inherently greater potential for higher order functionality with a net anti-inflammatory output. The present study begins to explore this fusion protein’s functional repertoire by demonstrating Fn14-TRAIL’s capacity to ameliorate MOG-induced EAE.     

Imaging in prostate cancer

Prostate cancer is the most common malignancy in men, in general. Most patients diagnosed with prostate cancer have localized disease confined to the prostate. A small percentage of patients with aggressive tumors will progress to develop local, extracapsular tumor extension and distant metastases. The aim of prostate cancer management is to identify and treat those patients with aggressive disease before they develop locally advanced or metastatic disease, and to avoid overtreating indolent tumors, which are unlikely to be life threatening. Imaging has been shown to be valuable in local staging of prostate cancer and as an aid to the management of clinically significant disease. In this article, we discuss the different established imaging modalities and emerging techniques for prostate cancer imaging in patients with clinically localized disease who may be suitable for radical treatment.     

Expression of expanded polyglutamine targets profilin for degradation and alters actin dynamics

Huntington's disease is caused by polyglutamine expansion in the huntingtin protein. Huntingtin directly interacts with profilin, a major actin monomer sequestering protein and a key integrator of signals leading to actin polymerization. We observed a progressive loss of profilin in the cerebral cortex of Huntington's disease patients, and in cell culture and Drosophila models of polyglutamine disease. This loss of profilin is likely due to increased degradation through the ubiquitin proteasome system. Profilin loss reduces the F/G actin ratio, indicating a shift in actin polymerization. Overexpression of profilin abolishes mutant huntingtin toxicity in cells and partially ameliorates the morphological and functional eye phenotype and extends lifespan in a transgenic polyglutamine Drosophila model. These results indicate a link between huntingtin and profilin and implicate profilin in Huntington's disease pathogenesis.     

Manual small incision cataract surgery: a viable option for cataract with pseudoexfoliation

International Ophthalmology - The aim of the study was to assess the spectrum of clinical presentation, intraoperative challenges and immediate surgical outcome of cataract patients with...     

Discovery of the HCV NS3/4A protease inhibitor (1R,5S)-N-[3-amino-1-(cyclobutylmethyl)-2,3-dioxopropyl]-3- [2(S)-[[[(1,1-dimethylethyl)amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]- 6,6-dimethyl-3-azabicyclo[3.1.0]hexan-2(S)-carboxamide (Sch 503034) II. Key steps in structure-based optimization

The structures of both the native holo-HCV NS3/4A protease domain and the protease domain with a serine 139 to alanine (S139A) mutation were solved to high resolution. Subsequently, structures were determined for a series of ketoamide inhibitors in complex with the protease. The changes in the inhibitor potency were correlated with changes in the buried surface area upon binding the inhibitor to the active site. The largest contribution to the binding energy arises from the hydrophobic interactions of the P1 and P2 groups as they bind to the S1 and S2 pockets [the numbering of the subsites is as defined in Berger, A.; Schechter, I. Philos. Trans. R. Soc. London, Ser. B 1970, 257, 249-264]. This correlation of the changes in potency with increased buried surface area contributed directly to the design of a potent tripeptide inhibitor of the HCV NS3/4A protease that is currently in clinical trials.     

Leukocyte polycyclic aromatic hydrocarbon-DNA adduct formation and colorectal adenoma

Consumption of charbroiled red meat and meat-derived polycyclic aromatic hydrocarbons (PAHs) has been associated with risk of colorectal adenoma, a precursor of colorectal cancer. Furthermore, leukocyte PAH-DNA adduct levels have been demonstrated to increase in response to charbroiled red meat intake but to date there have been no studies that have investigated the relationship between leukocyte PAH-DNA adduct levels and risk of colorectal adenoma. We investigated the relation of leukocyte PAH-DNA adduct formation and colorectal adenoma in a clinic-based case-control study of colorectal adenomas. The study comprised 82 cases of colorectal adenoma and 111 polyp-free controls, none of whom were current smokers. Leukocyte PAH-DNA adducts were measured by a sensitive chemiluminescence immunoassay using an antiserum elicited against DNA modified with (+/-)-7beta,8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydro-benzo[a]pyrene that recognizes several PAHs bound to human DNA. Leukocyte PAH-DNA adduct levels were higher among colorectal adenoma cases (median, 1.4 adducts per 10(8) nucleotides) than polyp-free controls (median, 1.2 adducts per 10(8) nucleotides) (P = 0.02). There was a positive association between PAH-DNA adduct level and adenoma prevalence: each unit increase in PAH-DNA adduct level (per 10(8) nucleotides) was associated with an odds ratio (OR) of 1.5 [95% confidence interval (CI), 1.1-2.2]. In addition, a comparison of the lowest quartile for PAH-DNA adduct level with the highest quartile yielded an OR of 2.8 (95% CI, 1.2-6.5; P(trend) = 0.048) for risk of colorectal adenoma. These data support a link between PAH exposure and colorectal adenoma.