CD133+ HCC cancer stem cells confer chemoresistance by preferential expression of the Akt/PKB survival pathway

The recent discovery of cancer stem cells (CSCs) has played a pivotal role in changing our view of carcinogenesis and chemotherapy. Based on this concept, CSCs are responsible for the formation and growth of neoplastic tissue and are naturally resistant to chemotherapy, explaining why traditional chemotherapies can initially shrink a tumor but fails to eradicate it in full, allowing eventual recurrence. Recently, we identified a CSC population in hepatocellular carcinoma (HCC) characterized by their CD133 phenotype. However, the molecular mechanism by which it escapes conventional therapies remains unknown. Here, we examined the sensitivity of these cells to chemotherapeutic agents (doxorubicin and fluorouracil) and the possible mechanistic pathway by which resistance may be regulated. Purified CD133+ HCC cells isolated from human HCC cell line and xenograft mouse models survived chemotherapy in increased proportions relative to most tumor cells which lack the CD133 phenotype; the underlying mechanism of which required the preferential expression of survival proteins involved in the Akt/PKB and Bcl-2 pathway. Treatment of CD133+ HCC cells with an AKT1 inhibitor, specific to the Akt/PKB pathway, significantly reduced the expression of the survival proteins that was normally expressed endogenously. In addition, treatment of unsorted HCC cells with both anticancer drugs in vitro significantly enriched the CD133+ subpopulation. In conclusion, our results show that CD133+ HCC cells contribute to chemoresistance through preferential activation of Akt/PKB and Bcl-2 cell survival response. Targeting of this specific survival signaling pathway in CD133+ HCC CSCs may provide a novel therapeutic model for the disease.

Immunobiology of mesenchymal stem cells

Mesenchymal stem cells (MSCs) can be isolated from almost all tissues and effectively expanded in vitro. Although their true in situ properties and biological functions remain to be elucidated, these in vitro expanded cells have been shown to possess potential to differentiate into specific cell lineages. It is speculated that MSCs in situ have important roles in tissue cellular homeostasis by replacing dead or dysfunctional cells. Recent studies have demonstrated that in vitro expanded MSCs of various origins have great capacity to modulate immune responses and change the progression of different inflammatory diseases. As tissue injuries are often accompanied by inflammation, inflammatory factors may provide cues to mobilize MSCs to tissue sites with damage. Before carrying out tissue repair functions, MSCs first prepare the microenvironment by modulating inflammatory processes and releasing various growth factors in response to the inflammation status. In this review, we focus on the crosstalk between MSCs and immune responses and their potential clinical applications, especially in inflammatory diseases.

Ferroptosis is induced following siramesine and lapatinib treatment of breast cancer cells

Ferroptosis is an iron-dependent, oxidative cell death, and is distinct from apoptosis, necrosis and autophagy. In this study, we demonstrated that lysosome disrupting agent, siramesine and a tyrosine kinase inhibitor, lapatinib synergistically induced cell death and reactive oxygen species (ROS) in MDA MB 231, MCF-7, ZR-75 and SKBr3 breast cancer cells over a 24 h time course. Furthermore, the iron chelator deferoxamine (DFO) significantly reduced cytosolic ROS and cell death following treatment with siramesine and lapatinib. Furthermore, we determined that FeCl3 levels were elevated in cells treated with siramesine and lapatinib indicating an iron-dependent cell death, ferroptosis. To confirm this, we treated cells with a potent inhibitor of ferroptosis, ferrastatin-1 that effectively inhibited cell death following siramesine and lapatinib treatment. The increase levels of iron could be due to changes in iron transport. We found that the expression of transferrin, which is responsible for the transport of iron into cells, is increased following treatment with lapatinib alone or in combination with siramesine. Knocking down of transferrin resulted in decreased cell death and ROS after treatment. In addition, ferroportin-1 (FPN) is an iron transport protein, responsible for removal of iron from cells. We found its expression is decreased after treatment with siramesine alone or in combination with lapatinib. Overexpression FPN resulted in decreased ROS and cell death whereas knockdown of FPN increased cell death after siramesine and lapatinib treatment. This indicates a novel induction of ferroptosis through altered iron regulation by treating breast cancer cells with a lysosome disruptor and a tyrosine kinase inhibitor.

Isolation of predominantly submicron-sized UHMWPE wear particles from periprosthetic tissues

A method of tissue digestion using sodium hydroxide was applied to the isolation and recovery of ultra-high-molecular-weight polyethylene (UHMWPE) particles from tissues around failed total hip replacements. Density gradient ultracentrifugation of the digested tissues was performed to separate the UHMWPE from cell debris and other particulates. Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC) verified that the recovered particles were UHMWPE. When viewed by scanning electron microscopy, individual particles were clearly observed and were either rounded or elongated. The majority were submicron in size. The application of this method to the study of particles from periprosthetic tissues may elucidate aspects of biomaterial particle size and shape that are important to the biologic response to, and clinical outcome of, total joint replacement.

Relaxin-3 in GABA projection neurons of nucleus incertus suggests widespread influence on forebrain circuits via G-protein-coupled receptor-135 in the rat

Relaxin-3 (RLX3) is a newly identified member of the relaxin/insulin peptide family that is highly conserved across a range of species from fish to mammals and is highly expressed in rat, mouse and human brain. Extensive pharmacological studies have demonstrated that RLX3 is a high affinity, selective ligand for G-protein-coupled receptor-135 (GPCR135, now classified as relaxin family peptide-3 receptor; RXFP3). In ongoing studies to understand the physiological functions of RLX3, the distribution of RLX3-containing neuronal elements in rat brain was determined by immunohistochemistry, using an affinity-purified polyclonal antiserum raised against a conserved segment of the RLX3 C-peptide (AS-R3(85-101)). Consistent with the distribution of RLX3 mRNA, neurons containing RLX3-like immunoreactivity (LI) were observed in the pontine nucleus incertus and the majority of these cells, which are known to express corticotropin-releasing factor receptor-1, were shown to express glutamic acid decarboxylase-65-immunoreactivity, suggesting a GABA phenotype. Nerve fibers and terminals containing RLX3-LI were observed adjacent to cells in the nucleus incertus and in various forebrain regions known to receive afferents from the nucleus incertus, including cortex, septum, hippocampus, thalamus, hypothalamus and midbrain. Regions that contained highest densities of RLX3-positive fibers included the medial septum, lateral preoptic area, lateral hypothalamus/medial forebrain bundle and ventral hippocampus; and additional fibers were observed in olfactory bulb and olfactory and frontal/cingulate cortices, bed nucleus of the stria terminalis, dorsal endopiriform, intergeniculate, and supramammillary nuclei, and the periaqueductal gray and dorsal raphe. The RLX3-positive network overlapped the regional distribution of GPCR135 mRNA and specific binding sites for an [125I]-GPCR135-selective, chimeric peptide. These anatomical findings further support the proposition that RLX3 is the endogenous ligand for GPCR135 in rat brain and provide evidence for broad modulatory activity of RLX3 in behavioral activation relating to autonomic and neuroendocrine control of metabolism and reproduction and higher-order processes such as stress and cognition.

Bax dimerizes via a symmetric BH3:groove interface during apoptosis

During apoptotic cell death, Bax and Bak change conformation and homo-oligomerize to permeabilize mitochondria. We recently reported that Bak homodimerizes via an interaction between the BH3 domain and hydrophobic surface groove, that this BH3:groove interaction is symmetric, and that symmetric dimers can be linked via the α6-helices to form the high order oligomers thought responsible for pore formation. We now show that Bax also dimerizes via a BH3:groove interaction after apoptotic signaling in cells and in mitochondrial fractions. BH3:groove dimers of Bax were symmetric as dimers but not higher order oligomers could be linked by cysteine residues placed in both the BH3 and groove. The BH3:groove interaction was evident in the majority of mitochondrial Bax after apoptotic signaling, and correlated strongly with cytochrome c release, supporting its central role in Bax function. A second interface between the Bax α6-helices was implicated by cysteine linkage studies, and could link dimers to higher order oligomers. We also found that a population of Bax:Bak heterodimers generated during apoptosis formed via a BH3:groove interaction, further demonstrating that Bax and Bak oligomerize via similar mechanisms. These findings highlight the importance of BH3:groove interactions in apoptosis regulation by the Bcl-2 protein family.

The critical role of geometry of porous hydroxyapatite delivery system in induction of bone by osteogenin, a bone morphogenetic protein

The collagenous extracellular matrix of bone obtained after dissociative extraction with 4 M guanidine-HCl is an optimal substratum for bone induction by osteogenin, a bone morphogenetic protein. As a proteinaceous substratum, this matrix and other collagen-based materials may be immunogenic. Thus, the search and discovery of a non-immunogenic substratum is a necessary prerequisite for the therapeutic application of the principle of bone induction to skeletal repair. Bovine osteogenin, purified greater than 50,000-fold and with an apparent molecular mass of 28-42 kilodaltons, was delivered into nonresorbable porous hydroxyapatite in granular and disc configuration. A total of 328 preparations were bioassayed for osteogenic activity by subcutaneous implantation into 164 Long-Evans rats. Specimens were harvested at day 7, 11 and 21 after implantation and subjected to alkaline phosphatase activity determination and histologic analysis. Osteogenin combined with discs of porous hydroxyapatite induced in vivo differentiation of the osteogenic phenotype in mesenchymal cells invading the three-dimensional porous space of the inorganic substratum. The geometry of the substratum had a profound influence on bone induction, since the expression of the osteogenic phenotype was solely confined in porous hydroxyapatite with disc configuration. Osteogenin did not induce bone differentiation when combined with granules of porous hydroxyapatite with identical pore dimensions. The finding that the biological activity of osteogenin can be restored and delivered by a substratum with defined geometry other than the insoluble collagenous matrix may form the basis of the potential therapeutic application of bone morphogenetic proteins.

Carbohydrate analysis of a chimeric recombinant monoclonal antibody by capillary electrophoresis with laser-induced fluorescence detection

A general method for the analysis of asparaginyl-linked (N-linked) carbohydrate moieties of an IgG1 monoclonal antibody is described here. The antibody, rituximab, is a mouse/human chimeric antibody to human CD20 antigen. The glycans present on rituximab are neutral complex biantennary oligosaccharides with zero, one, and two terminal galactose residues (G0, G1, and G2, respectively). To monitor the variation of the glycosylation during manufacture, the glycans were first enzymatically released from the antibody via digestion with peptide-N-glycosidase F, then derivatized with a charged fluorophore, 8-aminopyrene-1,3,6-trisulfonic acid and further separated by capillary electrophoresis with laser-induced fluorescence detection. All observed glycans were fully resolved, including the positional isomers of G1. The exact nature of the isomers in terms of the location of the terminal galactose was further characterized via multiple enzymatic digestion steps including mannosidase with activity toward specific Man(alpha 1,3) linkage. The optimization and several key parameters, i.e., enzymatic digestion and derivatization, in the assay development will be discussed. Moreover, to ensure that the assay can be used in routine lot release testing, the assay was validated and found to be accurate and precise. The analytical approach described is suitable for characterization as well as routine testing of the N-linked glycan content in any IgG1 monoclonal antibody and glycoproteins in general.

Geographic distribution, virologic and clinical characteristics of hepatitis B virus genotypes in China

The significance of hepatitis B virus (HBV) genotypes for the heterogeneity of chronic HBV infection and severity of liver disease is not well understood. The aim of this study was to determine the distribution and virologic characteristics of HBV genotypes in China and possible association with the diversity of liver disease. The study includes 1096 chronic HBV carriers from nine provinces in China. We collected clinical and laboratory data and analysed the HBV strains in sera by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and nucleotide sequencing techniques. The most common HBV genotypes were B (41%) and C (53%), while genotypes A and D were also found. A North-South divide was identified in genotype B and C distribution - genotype C was predominant in northern China, while genotype B was more prevalent in southern provinces. Patients with genotype B were younger than those with genotype C, and had a lower prevalence of HBeAg - 65%vs 72%, respectively (P = 0.03). However, the severity of liver disease did not differ significantly between patients infected with genotype B or C - neither when comparing liver function tests (1024 patients), nor hepatic inflammation and fibrosis (264 patients). Amongst 47 patients with genotype D (by PCR-RFLP), 37 (79%) were infected with a new subtype (designated Dc), having a recombination fragment from genotype C precore/core region. This is the first large-scale HBV genotype study from China and convincing documentation of the North-to-South gradient of genotypes C vs B in this country. HBV DNA recombination over the surface and precore/core genes increases the diversity of HBV strains and may have diagnostic and clinical implications.

Histologic comparison of regeneration in human intrabony defects when osteogenin is combined with demineralized freeze-dried bone allograft and with purified bovine collagen

A bone-inductive protein, osteogenin, has been isolated from long bones of humans and offers promise as a grafting material. Studies, however, suggest that osteogenin must be combined with a bone-derived matrix in order to initiate bone differentiation. The purpose of this study was to determine if osteogenin combined with demineralized freeze dried bone allograft (DFDBA), a bone-derived matrix, and with a bovine tendon-derived matrix will enhanced regeneration of intrabony defects in humans. The tendon-derived matrix and DFDBA used alone served as controls. The ability of each material to form a new attachment apparatus was evaluated independently in submerged and nonsubmerged environments in 2 patient populations. Lymphocyte testing was performed to assess development of an immune reaction to osteogenin. The most apical level of calculus on the root served as the histologic reference point to measure regeneration. Biopsies were obtained at 6 months and regeneration was measured histomorphometrically by 2 blinded evaluators. Serial sections from 36 submerged defects in 8 patients and 50 nonsubmerged defects in 6 patients were submitted for statistical analysis. Mean results indicate that osteogenin combined with DFDBA significantly enhanced regeneration of a new attachment apparatus and component tissues in a submerged environment. DFDBA plus osteogenin and DFDBA alone formed significantly more new attachment apparatus and component tissues than either the tendon-derived matrix plus osteogenin or the tendon-derived matrix alone in both submerged and nonsubmerged environments. There were no significant differences between the tendon-derived matrix plus osteogenin and the tendon-derived matrix alone in either the submerged or nonsubmerged environment. Osteogenin does not impair normal lymphocyte blastogenesis at 6 months postsurgical challenge.

Combinations of weak classifiers

To obtain classification systems with both good generalization performance and efficiency in space and time, we propose a learning method based on combinations of weak classifiers, where weak classifiers are linear classifiers (perceptrons) which can do a little better than making random guesses. A randomized algorithm is proposed to find the weak classifiers. They are then combined through a majority vote. As demonstrated through systematic experiments, the method developed is able to obtain combinations of weak classifiers with good generalization performance and a fast training time on a variety of test problems and real applications. Theoretical analysis on one of the test problems investigated in our experiments provides insights on when and why the proposed method works. In particular, when the strength of weak classifiers is properly chosen, combinations of weak classifiers can achieve a good generalization performance with polynomial space- and time-complexity.

Anti-biofilm effect of dental adhesive with cationic monomer

The incorporation of polymerizable cationic monomers has been attempted to generate dental resinous materials with antibacterial activity. This study tested the hypothesis that a dental adhesive containing a cationic monomer, methacryloxylethyl cetyl dimethyl ammonium chloride (DMAE-CB), would influence biofilm formation and gtf gene expression of Streptococcus mutans. The effect of the photo-polymerized DMAE-CB-incorporated adhesive on in vitro biofilm accumulation was investigated with spectrophotometry and scanning electron microscopy. The relative level of gtf gene expression by Streptococcus mutans in the biofilm was quantified by real-time reverse-transcription polymerase chain-reaction. The DMAE-CB-incorporated adhesive significantly decreased bio-film accumulation on its surface (P < 0.05), and suppressed the expression of gtfB and gtfC of Streptococcus mutans in the biofilm (P < 0.05). The results suggest that the cured DMAE-CB-incorporated adhesive may hamper biofilm accumulation via selective down-regulation of the expression of gtf genes in Streptococcus mutans.

Desmosine as a biomarker of elastin degradation in COPD: current status and future directions

Desmosine (DES) and isodesmosine (IDES) are two unusual, tetrafunctional, pyridinium ring-containing amino acids involved in elastin cross-linking. Being amino acids unique to mature, cross-linked elastin, they are useful for discriminating peptides derived from elastin breakdown from precursor elastin peptides. According to these features, DES and IDES have been extensively discussed as potentially attractive indicators of elevated lung elastic fibre turnover and markers of the effectiveness of agents with the potential to reduce elastin breakdown. In the present manuscript, immunology-based and separation methods for the evaluation of DES and IDES are discussed, along with studies reporting increased levels of urine excretion in chronic obstructive pulmonary disease (COPD) patients with and without alpha(1)-antitrypsin deficiency. The results of the application of DES and IDES as surrogate end-points in early clinical trials in COPD are also reported. Finally, recent advances in detection techniques, including liquid chromatography tandem mass spectrometry and high-performance capillary electrophoresis with laser-induced fluorescence, are discussed. These techniques allow detection of DES and IDES at very low concentration in body fluids other than urine, such as plasma or sputum, and will help the understanding of whether DES and IDES are potentially useful in monitoring therapeutic intervention in COPD.

Renal Na(+)-phosphate cotransport in murine X-linked hypophosphatemic rickets. Molecular characterization

The X-linked Hyp mouse is characterized by a specific defect in proximal tubular phosphate (Pi) reabsorption that is associated with a decrease in Vmax of the high affinity Na(+)-Pi cotransport system in the renal brush border membrane. To understand the mechanism for Vmax reduction, we examined the effect of the Hyp mutation on renal expression of Na(+)-Pi cotransporter mRNA and protein. Northern hybridization of renal RNA with a rat, renal-specific Na(+)-Pi cotransporter cDNA probe (NaPi-2) (Magagnin et al. 1993. Proc. Natl. Acad. Sci. USA. 90:5979-5983.) demonstrated a reduction in a 2.6-kb transcript in kidneys of Hyp mice relative to normal littermates (NaPi-2/beta-actin mRNA = 57 +/- 6% of normal in Hyp mice, n = 6, P < 0.01). Na(+)-Pi cotransport, but not Na(+)-sulfate cotransport, was approximately 50% lower in Xenopus oocytes injected with renal mRNA extracted from Hyp mice when compared with that from normal mice. Hybrid depletion experiments documented that the mRNA-dependent expression of Na(+)-Pi cotransport in oocytes was related to NaPi-2. Western analysis demonstrated that NaPi-2 protein is also significantly reduced in brush border membranes of Hyp mice when compared to normals. The present data demonstrate that the specific reduction in renal Na(+)-Pi cotransport in brush border membranes of Hyp mice can be ascribed to a proportionate decrease in the abundance of Na(+)-Pi cotransporter mRNA and protein.

Phalloplasty in female-to-male transsexuals using free radial osteocutaneous flap: a series of 22 cases

From July 1994 to December 1996, 22 cases of primary female transsexualism received phalloplasty using free radial forearm osteocutaneous flaps in The Veterans General Hospital, Taipei, Taiwan. Follow-up period ranged from 6 months to 35 months. No complete flap loss and one partial loss (10% reduction) were noted after operation. The urethrocutaneous fistula rate was 40.9%, needing fistula repair surgery. Urethral stricture was noted in three cases (13.7%). Significant donor forearm morbidity was noted in two cases (9.1%) including one who suffered from radius bone fracture. All preserved 'clitorises' had intact erotic sensation and all neophalli gained protective sensation within 9 months. No 'penile fracture' was noted. In nine cases that have regular sexual activities, the sexual performance was rated as satisfactory. We share our experience and recommend that the free radial forearm osteocutaneous tubing flap is a promising choice for phalloplasty in female-to-male transsexuals.

Phosphorylation-independent activity of the response regulators AlgB and AlgR in promoting alginate biosynthesis in mucoid Pseudomonas aeruginosa

Overproduction of the capsular polysaccharide alginate appears to confer a selective advantage for Pseudomonas aeruginosa in the lungs of cystic fibrosis patients. The regulators AlgB and AlgR, which are both required as positive activators in alginate overproduction, have homology with the regulator class of two-component environmental responsive proteins which coordinate gene expression through signal transduction mechanisms. Signal transduction in this class of proteins generally occurs via autophosphorylation of the sensor kinase protein and phosphotransfer from the sensor to a conserved aspartate residue, which is present in the amino terminus of the response regulator. Recently, kinB was identified downstream of algB and was shown to encode the cognate histidine protein kinase that efficiently phosphorylates AlgB. However, we show here that a null mutation in kinB in a mucoid cystic fibrosis isolate, P. aeruginosa FRD1, did not block alginate production. The role of the conserved aspartate residue in the phosphorylation of AlgB was examined. The predicted phosphorylation site of AlgB (D59) was mutated to asparagine (N), and a derivative of an AlgB lacking the entire amino-terminal phosphorylation domain (AlgB delta1-145) was constructed. A hexahistidine tag was included at the amino terminus of the wild-type (H-AlgB), H-AlgB delta1-145, and mutant (H-AlgB.59N) AlgB proteins. These derivatives were purified by Ni2+ affinity chromatography and examined for in vitro phosphorylation by the purified sensor kinase protein, KinB. The results indicated that while KinB efficiently phosphorylated H-AlgB, no phosphorylation of H-AlgB delta1-145 or H-AlgB.D59N was apparent. An allelic exchange system was developed to transfer mutant algB alleles onto the chromosome of a P. aeruginosa algB mutant to examine the effect on alginate production. Despite the defect in AlgB phosphorylation, P. aeruginosa strains expressing AlgB.D59N or H-AlgB delta1-145 remained mucoid. The roles of the conserved aspartate residues in the phosphorylation of AlgR were also examined. As seen with AlgB, mutations in the predicted phosphorylation site of AlgR (AlgR.D54N and AlgR.D85N) did not affect alginate production. These results indicate that in vivo phosphorylation of AlgB and AlgR are not required for their roles in alginate production. Thus, the mechanism by which these response regulators activate alginate genes in mucoid P. aeruginosa appears not to be mediated by conventional phosphorylation-dependent signal transduction.

Two functionally different synergies during arm reaching movements involving the trunk

1. To address the problem of the coordination of a redundant number of degrees of freedom in motor control, we analyzed the influence of voluntary trunk movements on the arm endpoint trajectory during reaching. 2. Subjects made fast noncorrected planar movements of the right arm from a near to a far target located in the ipsilateral work space at a 45 degrees angle to the sagittal midline of the trunk. These reaching movements were combined with a forward or a backward sagittal motion of the trunk. 3. The direction, positional error, curvature, and velocity profile of the endpoint trajectory remained invariant regardless of trunk movements. Trunk motion preceded endpoint motion by approximately 175 ms, continued during endpoint movement to the target, and outlasted it by 200 ms. This sequence of trunk and arm movements was observed regardless of the direction of the endpoint trajectory (to or from the far target) or trunk movements (forward or backward). 4. Our data imply that reaching movements result from two control synergies: one coordinates trunk and arm movements leaving the position of the endpoint unchanged, and the other produces interjoint coordination shifting the arm endpoint to the target. The use of functionally different synergies may underlie a solution of the redundancy problem.

Norepinephrine release in medial amygdala facilitates activation of the hypothalamic-pituitary-adrenal axis in response to acute immobilisation stress

Activation of the brain noradrenergic system during stress plays an important integrative function in coping and stress adaptation by facilitating transmission in many brain regions involved in regulating behavioural and physiological components of the stress response. The medial amygdala (MeA) has been implicated in modulation of stress-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis, and MeA is a target of innervation from brainstem noradrenergic neurones. However, it is not known whether, and to what extent, activation of the ascending noradrenergic innervation of MeA might modulate stress-induced adrenocorticotropic hormone (ACTH) secretion. In the first experiment in this study, we measured extracellular norepinephrine (NE) levels in MeA using in vivo microdialysis. The concentration of NE in dialysate samples collected in MeA was elevated by more than three-fold over baseline in response to acute immobilisation stress, providing evidence of a possible modulatory role for NE in the MeA during stress. This potential role was then assessed in the second experiment by measuring changes in the elevation of plasma ACTH concentration induced by acute immobilisation stress immediately following bilateral microinjections of alpha1- or beta-adrenergic receptor antagonists directly into MeA. Compared to vehicle-injected controls, the alpha1-receptor antagonist benoxathian dose-dependently and significantly attenuated the ACTH response to acute stress, whereas combined beta1/beta2-receptor blockade in MeA had only a modest effect. These results indicate that MeA does play a role in the stress response, and support the hypothesis that stress-induced activation of NE release in MeA, acting primarily through alpha1 receptors, facilitates activation of the HPA axis in response to acute stress.

Mechanism of action of a WWTR1(TAZ)-CAMTA1 fusion oncoprotein

The WWTR1 (protein is known as TAZ)-CAMTA1 (WC) fusion gene defines epithelioid hemangioendothelioma, a malignant vascular cancer. TAZ (transcriptional coactivator with PDZ binding motif) is a transcriptional coactivator and end effector of the Hippo tumor suppressor pathway. It is inhibited by phosphorylation by the Hippo kinases LATS1 and LATS2. Such phosphorylation causes cytoplasmic localization, 14-3-3 protein binding and the phorphorylation of a terminal phosphodegron promotes ubiquitin-dependent degradation (the phosphorylation of the different motifs has several effects). CAMTA1 is a putative tumor suppressive transcription factor. Here we demonstrate that TAZ-CAMTA1 (TC) fusion results in its nuclear localization and constitutive activation. Consequently, cells expressing TC display a TAZ-like transcriptional program that causes resistance to anoikis and oncogenic transformation. Our findings elucidate the mechanistic basis of TC oncogenic properties, highlight that TC is an important model to understand how the Hippo pathway can be inhibited in cancer, and provide approaches for targeting this chimeric protein.

Molecular cloning and characterization of a novel CXC chemokine macrophage inflammatory protein-2 gamma chemoattractant for human neutrophils and dendritic cells

Chemokines play important roles in leukocyte trafficking as well as function regulation. In this study, we described the identification and characterization of a novel CXC chemokine from a human dendritic cell (DC) cDNA library, the full-length cDNA of which contains an open reading frame encoding 111 aa with a putative signal peptide of 34 aa. This CXC chemokine shares greatest homology with macrophage inflammatory protein (MIP)-2alphabeta, hence is designated as MIP-2gamma. Mouse MIP-2gamma was identified by electrocloning and is highly homologous to human MIP-2gamma. Northern blotting revealed that MIP-2gamma was constitutively and widely expressed in most normal tissues with the greatest expression in kidney, but undetectable in most tumor cell lines except THP-1 cells. In situ hybridization analysis demonstrated that MIP-2gamma was mainly expressed by the epithelium of tubules in the kidney and hepatocytes in the liver. Although no detectable expression was observed in freshly isolated or PMA-treated monocytes, RT-PCR analysis revealed MIP-2gamma expression by monocyte-derived DC. Recombinant MIP-2gamma from 293 cells is about 9.5 kDa in size and specifically detectable by its polyclonal Ab developed by the immunization with its 6His-tagged fusion protein. The eukaryotically expressed MIP-2gamma is a potent chemoattractant for neutrophils, and weaker for DC, but inactive to monocytes, NK cells, and T and B lymphocytes. Receptor binding assays showed that MIP-2gamma does not bind to CXCR2. This implies that DC might contribute to the innate immunity through the production of neutrophil-attracting chemokines and extends the knowledge about the regulation of DC migration.

Effect of air pollution on daily mortality in Hong Kong

In different weather conditions, constituents and concentrations of pollutants, personal exposure, and biologic responses to air pollution may vary. In this study we assessed the effects of four air pollutants on mortality in both cool and warm seasons in Hong Kong, a subtropical city. Daily counts of mortality, due to all nonaccidental causes, and cardiovascular and respiratory diseases were modeled with daily pollutant concentrations [24-hr means for nitrogen dioxide, sulfur dioxide, and particulate matter < 10 microm in aerodynamic diameter (PM(10)); 8-hr mean for ozone]. using Poisson regression. We controlled for confounding factors by fitting the terms in models, in line with those recommended by the APHEA (Air Pollution and Health: a European Approach) protocol. Exposure-response relationships in warm and cool seasons were examined using generalized additive modeling. During the cool season, for a linear extrapolation of 10th-90th percentiles in the pollutant concentrations of all oxidant pollutants, NO(2), SO(2), and O(3), we found significant effects on all the mortality outcomes under study, with relative risks (RR) of 1.04-1.10 (p < 0.038, except p = 0.079 for SO(2) on respiratory mortality). We observed consistent positive exposure-response relationships during the cool season but not during the warm season. The effects of PM(10) were marginally significant (RR = 1.06; p = 0.054) for respiratory mortality but not for the other outcomes (p > 0.135). In this subtropical city, local air quality objectives should take into account that air pollution has stronger health effects during the cool rather than warm season and that oxidant pollutants are more important indicators of health effects than particulates.