Alleviation of Dermatophagoides microceras-induced allergy by an immunomodulatory protein, FIP-fve, from Flammulina velutipes in mice

Asthma is a major public health concern. Its greatest risk factor is house dust mite (HDM). Dermatophagoides microceras (Der m) is a type of HDM, and in central Taiwan, there is approximately 80% prevalence of sensitization to Der m. FIP-fve is a fungal immunomodulatory protein (FIP) isolated from the fungus Flammulina velutipes, and exhibits anti-inflammatory properties. To investigate whether FIP-fve affects Der m-induced asthma and inflammation, we evaluated hyper-responsiveness (AHR), pathological changes, and cytokines in mice. We demonstrated that oral FIP-fve decreased Der m-induced airway AHR, airway inflammation, cell infiltration, and expression of cytokines in the bronchoalveolar lavage fluid of Balb/c mice. The results of this study suggest that FIP-fve suppresses asthma, inflammation, and respiratory pathogenesis stimulated by Der m. FIP-fve is able to maintain immunomodulatory activity even in simulated gastric fluid and intestinal fluid. FIP-fve could be a safe and stable agent for suppression of allergic asthma.

Surgical management of biliary cystadenoma and cystadenocarcinoma of the liver

Biliary cystadenoma (BCA) and biliary cystadenocarcinoma (BCAC) are rare biliary duct neoplasms. This study investigated reasonable management strategies of cystic neoplasms in the liver. Charts of 39 BCA/BCAC patients (9 males, 30 female; median age 53.74 ± 14.50 years) who underwent surgery from January 1999 to December 2009 were reviewed retrospectively. Cyst fluid samples of 32 BCA/BCAC patients and 40 simple hepatic cyst patients were examined for the tumor markers carbohydrate associated antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA). The most frequent symptoms were abdominal pain (N = 10), abdominal mass (N = 7), abdominal distension (N = 4), jaundice (N = 2), and fever (N = 3); the remaining patients showed no clinical symptoms. Liver resection (N = 17) or enucleation (N = 22) was performed in the 39 patients. Ultimately, 35 patients were diagnosed with intrahepatic BCA and four patients were diagnosed with BCAC. The median CA19-9 level was significantly higher in BCA/BCAC patients than in simple hepatic cyst patients. The median CEA levels in BCA/BCAC patients and controls were 6.83 ± 2.43 and 4.21 ± 2.91 mg/L, respectively. All symptoms were resolved after surgery, and only one BCAC patient showed recurrence. The incidence of intrahepatic cystic lesions was 1.7%. Increased CA19-9 levels in the cyst fluid is a helpful marker for distinguishing BCA/BCAC from common simple cysts. The presence of coarse calcifications is suggestive of BCAC. Complete surgical removal of these lesions yielded satisfying long-term outcomes with a very low recurrence rate.

Dioscorin pre-treatment protects A549 human airway epithelial cells from hydrogen peroxide-induced oxidative stress

Hydrogen peroxide (H(2)O(2)) is a highly reactive oxygen species involved in lung and bronchial epithelium injury. Increased H(2)O(2) levels have been reported in expired breath condensates of patients with inflammatory airway diseases such as chronic obstructive pulmonary disease. Protecting airway epithelial cells from oxidative stress is an important task in the prevention and management of airway diseases. Previous studies demonstrate that yam (Dioscorea batatas Decne) has antioxidant and anti-trypsin activities. This study evaluated the validity of dioscorin in vitro. The results showed that dioscorin attenuated the alteration of H(2)O(2) on G2/M cell cycle arrest. This might be associated with the activation of IκB and subsequent inactivation of NF-κB. Furthermore, dioscorin suppressed IL-8 secretion and reduced changes of adhesion molecule expressions in H(2)O(2)-injured A549 cells. These results help in understanding the potential of traditional Chinese herbal medicine as treatment for airway inflammatory diseases.

Imbalanced matriptase pericellular proteolysis contributes to the pathogenesis of malignant B-cell lymphomas

Membrane-associated serine protease matriptase is widely expressed by epithelial/carcinoma cells in which its proteolytic activity is tightly controlled by the Kunitz-type protease inhibitor, hepatocyte growth factor activator inhibitor (HAI-1). We demonstrate that, although matriptase is not expressed in lymphoid hyperplasia, roughly half of the non-Hodgkin B-cell lymphomas analyzed express significant amounts of matriptase. Furthermore, a significant proportion of these tumors express matriptase in the absence of HAI-1. Aggressive Burkitt lymphoma was more likely than indolent follicular lymphoma to express matriptase alone (86% versus 36%). In the absence of significant HAI-1 expression, the lymphoma cells activate and shed active matriptase when the cells are stimulated with mildly acidic buffer or the hypoxia-mimicking agent, CoCl2. The shed active matriptase can initiate pericellular proteolytic cascades by activating urokinase-type plasminogen activator on the cell surface of monocytes, and it can activate prohepatocyte growth factor. In addition, matriptase knockdown suppressed proliferation and colony-forming ability of neoplastic B cells in culture and growth as tumor xenografts in mice. Furthermore, exogenous expression of HAI-1 significantly suppressed proliferation of neoplastic B cells. These studies suggest that dysregulated pericellular proteolysis as a result of unregulated matriptase expression with limited HAI-1 may contribute to the pathological characteristics of several human B-cell lymphomas through modulation of the tumor microenvironment and enhanced tumor growth.

Reciprocal regulation of microRNA-99a and insulin-like growth factor I receptor signaling in oral squamous cell carcinoma cells

Background

MicroRNAs (miRNAs), small noncoding RNA molecules can function as oncogenes or tumor suppressors in tumorigenesis. Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers worldwide with a 5-year survival rate of approximately 50%.

Methods

The expression of microRNA-99a (miR-99a) in OSCC tissues and cell lines was investigated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis. The functions of miR-99a in migration/invasion and lung colonization were determined by transwell and tail vein injection assays, respectively. Specific targets of miR-99a were determined by software prediction, correlation with target protein expression, and luciferase reporter assay. The signaling pathways involved in regulation of miR-99a were investigated using the kinase inhibitors.

Results

We observed reduced levels of miR-99a, identified as one of the most downregulated miRNA in OSCC and all tested OSCC cell lines compared to normal oral keratinocytes. Ectopic miR-99a expression in OSCC cells markedly reduced migration and invasion in vitro as well as lung colonization in vivo. When evaluating the specific targets of miR-99a, we found that ectopic miR-99a expression downregulates insulin-like growth factor 1 receptor (IGF1R) protein and that the expression of miR-99a correlates negatively with IGF1R protein in OSCC cells. Insertion of the 3′UTR of IGF1R mRNA into the 3′UTR of a reporter gene markedly reduced luciferase activity in OSCC cells expressing miR-99a, suggesting that miR-99a reduces luciferase activity by targeting the 3′UTR of IGF1R mRNA. When evaluating the mechanisms of miR-99a downregulation, we observed the upregulation of miR-99a expression in serum-starved conditions and its suppression in response to insulin-like growth factor (IGF1) stimulation. Inhibitors of phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) kinase inhibited IGF1-induced suppression of miR-99a, suggesting the negative regulation of miR-99a expression by IGF1R signaling.

Conclusion

Overall, results indicate that miR-99a functions as a tumor metastasis suppressor in OSCC cells and mutually regulates IGF1R expression in a reciprocal regulation.

Predictors of Taiwanese baccalaureate nursing students' physio-psycho-social responses during clinical practicum

The nursing educational process may contribute to stress in nursing students, particularly during clinical rotations. This descriptive study explored the relationships between perceived stress, coping behaviors, personality traits, and physio-psycho-social responses in a clinical practicum among baccalaureate nursing students and identified predictors for physio-psycho-social responses. A cross-sectional design was employed. One hundred and one juniors enrolled in a four-year baccalaureate nursing program in Taiwan participated in this study. Four structured questionnaires were utilized to collect data. Multiple regression analysis showed that three predictors accounted for 53.2% of the variance in students' physio-psycho-social responses, including perceived stress, students' gender, and personality traits. The implication for nursing educators is providing immediate assistance and appropriate support to guide students through difficult learning when they need. Nursing instructors also should pay attention to students' gender-linked differences and be aware of individuals' personality traits, especially those with emotional instability, unsocial behaviors, and depressive signs.

Efficient generation of lung and airway epithelial cells from human pluripotent stem cells

The ability to generate lung and airway epithelial cells from human pluripotent stem cells (hPSCs) would have applications in regenerative medicine, drug screening and modeling of lung disease, and studies of human lung development. We established, based on developmental paradigms, a highly efficient method for directed differentiation of hPSCs into lung and airway epithelial cells. Long-term differentiation in vivo and in vitro yielded basal, goblet, Clara, ciliated, type I and type II alveolar epithelial cells. Type II alveolar epithelial cells generated were capable of surfactant protein-B uptake and stimulated surfactant release, providing evidence of specific function. Inhibiting or removing agonists to signaling pathways critical for early lung development in the mouse—retinoic acid, Wnt and BMP—recapitulated defects in corresponding genetic mouse knockouts. The capability of this protocol to generate most cell types of the respiratory system suggests its utility for deriving patient-specific therapeutic cells.

Differentiated epithelial- and mesenchymal-like phenotypes in subcutaneous mouse xenografts using diffusion weighted-magnetic resonance imaging

Epithelial-mesenchymal transition (EMT) is important for tumor metastasis. Detection of EMT protein expression and observation of morphological changes are commonly used to identify EMT. Diffusion-weighted magnetic resonance imaging (DW-MRI) and measuring apparent diffusion coefficient (ADC) values are noninvasive techniques for characterizing tumor microenvironments. We investigated the difference in ADC values between epithelial- and mesenchymal-like subcutaneous mouse xenografted tumors using DW-MRI. Epithelial-like MM189 PB-Klf4 and BL322 PB-Klf4 cells were generated from tumor suppressive Kruppel-like factor 4 (Klf4)-expressing mesenchymal-like MM189 and BL322 cells. The ADC values of xenografted tumors from epithelial-like MM189 PB-Klf4 and BL322 PB-Klf4 were significantly lower than those from their mesenchymal-like counterparts (p < 0.05 and p < 0.01, respectively). Our results suggested that DW-MRI is a potential tool for observing mesenchymal- or epithelial-like characteristics of subcutaneous xenografted tumors.

Arsenic induces reactive oxygen species-caused neuronal cell apoptosis through JNK/ERK-mediated mitochondria-dependent and GRP 78/CHOP-regulated pathways

Arsenic (As), a well-known high toxic metal, is an important environmental and industrial contaminant, and it induces oxidative stress, which causes many adverse health effects and diseases in humans, particularly in inorganic As (iAs) more harmful than organic As. Recently, epidemiological studies have suggested a possible relationship between iAs exposure and neurodegenerative disease development. However, the toxicological effects and underlying mechanisms of iAs-induced neuronal cell injuries are mostly unknown. The present study demonstrated that iAs significantly decreased cell viability and induced apoptosis in Neuro-2a cells. iAs also increased oxidative stress damage (production of malondialdehyde (MDA) and ROS, and reduction of Nrf2 and thioredoxin protein expression) and induced several features of mitochondria-dependent apoptotic signals, including: mitochondrial dysfunction, the activations of PARP and caspase cascades, and the increase in caspase-3 activity. Pretreatment with the antioxidant N-acetylcysteine (NAC) effectively reversed these iAs-induced responses. iAs also increased the phosphorylation of JNK and ERK1/2, but did not that p38-MAPK, in treated Neuro-2a cells. NAC and the specific JNK inhibitor (SP600125) and ERK1/2 inhibitor (PD98059) abrogated iAs-induced cell cytotoxicity, caspase-3/-7 activity, and JNK and ERK1/2 activation. Additionally, exposure of Neuro-2a cells to iAs triggered endoplasmic reticulum (ER) stress identified through several key molecules (GRP 78, CHOP, XBP-1, and caspase-12), which was prevented by NAC. Transfection with GRP 78- and CHOP-specific si-RNA dramatically suppressed GRP 78 and CHOP expression, respectively, and attenuated the activations of caspase-12, -7, and -3 in iAs-exposed cells. Therefore, these results indicate that iAs induces ROS causing neuronal cell death via both JNK/ERK-mediated mitochondria-dependent and GRP 78/CHOP-triggered apoptosis pathways.

Matriptase expression and zymogen activation in human pilosebaceous unit

Studies of human genetic disorders and mouse models reveal the important roles of matriptase in hair growth. Here, we investigate matriptase expression and zymogen activation in hair follicles. We show: 1) layer-dependent distribution patterns, with much higher matriptase expression in cells of the outer root sheath and matrix cells of the hair bulb than in cells of the inner root sheath; 2) cycle-dependent expression patterns, with matriptase expressed in the anagen and catagen phases of the hair lifecycle, but not in the telogen phase; 3) reduced expression of the matriptase inhibitor, HAI-1, in the catagen phase, suggesting increased proteolytic activity in this phase; and 4) definitive matriptase zymogen activation patterns, with the highest matriptase activation observed in matrix cells and outer root sheath cells in the isthmus/bulge region. In sebaceous glands, matriptase is highly expressed in basal and ductal cells, with much lower expression in the differentiated, lipid-filled cells of the interior. We also show that matriptase potently activates hepatocyte growth factor (HGF) in vitro, and that the HGF receptor, c-Met, is co-expressed in those cells that express activated matriptase. Our observations suggest that the matriptase-HGF-c-MET pathway has the potential to be engaged, primarily in proliferative cells rather than terminally differentiated epithelial cells of the human pilosebaceous unit.

Functional activity of RLIM/Rnf12 is regulated by phosphorylation-dependent nucleocytoplasmic shuttling

In mice, the ubiquitin ligase RLIM/Rnf12 is a critical survival factor for mammary milk-producing alveolar cells, but little is known about how its activity is regulated. It is shown here that RLIM shuttles between the nucleus and cytoplasm in a phosphorylation-dependent manner, and shuttling is important for its alveolar survival function.

The X-linked gene Rnf12 encodes the ubiquitin ligase really interesting new gene (RING) finger LIM domain–interacting protein (RLIM)/RING finger protein 12 (Rnf12), which serves as a major sex-specific epigenetic regulator of female mouse nurturing tissues. Early during embryogenesis, RLIM/Rnf12 expressed from the maternal allele is crucial for the development of extraembryonic trophoblast cells. In contrast, in mammary glands of pregnant and lactating adult females RLIM/Rnf12 expressed from the paternal allele functions as a critical survival factor for milk-producing alveolar cells. Although RLIM/Rnf12 is detected mostly in the nucleus, little is known about how and in which cellular compartment(s) RLIM/Rnf12 mediates its biological functions. Here we demonstrate that RLIM/Rnf12 protein shuttles between nucleus and cytoplasm and this is regulated by phosphorylation of serine S214 located within its nuclear localization sequence. We show that shuttling is important for RLIM to exert its biological functions, as alveolar cell survival activity is inhibited in cells expressing shuttling-deficient nuclear or cytoplasmic RLIM/Rnf12. Thus regulated nucleocytoplasmic shuttling of RLIM/Rnf12 coordinates cellular compartments during mammary alveolar cell survival.

miR-989 is required for border cell migration in the Drosophila ovary

microRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by destabilizing target transcripts and/or inhibiting their translation. miRNAs are thought to have roles in buffering gene expression to confer robustness. miRNAs have been shown to play important roles during tissue development to control cell proliferation, differentiation and morphogenesis. Many miRNAs are expressed in the germ line of Drosophila, and functions have been reported for a few miRNAs in maintenance of stem cell proliferation during oogenesis. Here, we analyse the function of Drosophila miR-989 in oogenesis. miR-989 is abundant in ovaries. Mutants lacking miR-989 did not display gross abnormalities affecting egg chamber formation or maturation. However, the migration of the border cell cluster was severely delayed in miR-989 mutant egg chambers. We demonstrate that miR-989 function is required in the somatic cells in the egg chamber, not in germ line cells for border cell migration. Loss of miR-989 from a fraction of the border cell cluster was sufficient to impair cluster migration as a whole, suggesting a role in border cells. Gene ontology analysis reveals that many predicted miR-989 target mRNAs are implicated in regulating cell migration, cell projection morphogenesis, cell adhesion as well as receptor tyrosine kinase and ecdysone signalling, consistent with an important regulatory role for miR-989 in border cell migration.

Perceptions about preventing hepatocellular carcinoma among patients with chronic hepatitis in Taiwan

AIM: To measure patient perceptions about preventing hepatocellular carcinoma (HCC) and to predict the factors that influence patient willingness to receive therapy.

METHODS: A cross-sectional descriptive study was conducted at an outpatient clinic of a medical institution in southern Taiwan. Four hundred patients with chronic hepatitis B/C were recruited as participants. Two structured questionnaires based on the health belief model were utilized in this study, including the scales of perceptions about preventing HCC and knowledge of hepatitis B/C.

RESULTS: The statistical results demonstrated that the participants’ perceived susceptibility (r = -0.22, P < 0.001), benefits (r = -0.11, P = 0.028) and cues to action (r = -0.12, P = 0.014) about the prevention of HCC was significantly correlated with their age. The participants’ perceptions were also associated with their educational levels, household incomes and knowledge of hepatitis. Older patients and those with a lower socioeconomic status tended to have negative perceptions and less knowledge of hepatitis. Multivariate logistic regression further indicated that the participants’ age (B = -0.044, SE = 0.017, odds ratio = 0.957, P = 0.008, 95%CI: 0.926-0.989) and perceived barriers (B = -0.111, SE = 0.030, odds ratio = 0.895, P < 0.001, 95%CI: 0.845-0.949) were correlated with their willingness to receive antiviral therapy.

CONCLUSION: Healthcare professionals should provide appropriate and effective guidance to increase their patients’ awareness and to decrease the perceived barriers for continuing surveillance and antiviral therapy.

Cadmium induces apoptosis in pancreatic β-cells through a mitochondria-dependent pathway: the role of oxidative stress-mediated c-Jun N-terminal kinase activation

Cadmium (Cd), one of well-known highly toxic environmental and industrial pollutants, causes a number of adverse health effects and diseases in humans. The growing epidemiological studies have suggested a possible link between Cd exposure and diabetes mellitus (DM). However, the toxicological effects and underlying mechanisms of Cd-induced pancreatic β-cell injury are still unknown. In this study, we found that Cd significantly decreased cell viability, and increased sub-G1 hypodiploid cells and annexin V-Cy3 binding in pancreatic β-cell-derived RIN-m5F cells. Cd also increased intracellular reactive oxygen species (ROS) generation and malondialdehyde (MDA) production and induced mitochondrial dysfunction (the loss of mitochondrial membrane potential (MMP) and the increase of cytosolic cytochrome c release), the decreased Bcl-2 expression, increased p53 expression, poly (ADP-ribose) polymerase (PARP) cleavage, and caspase cascades, which accompanied with intracellular Cd accumulation. Pretreatment with the antioxidant N-acetylcysteine (NAC) effectively reversed these Cd-induced events. Furthermore, exposure to Cd induced the phosphorylations of c-jun N-terminal kinases (JNK), extracellular signal-regulated kinases (ERK)1/2, and p38-mitogen-activated protein kinase (MAPK), which was prevented by NAC. Additionally, the specific JNK inhibitor SP600125 or JNK-specific small interference RNA (si-RNA) transfection suppressed Cd-induced β-cell apoptosis and related signals, but not ERK1/2 and p38-MAPK inhibitors (PD98059 and SB203580) did not. However, the JNK inhibitor or JNK-specific si-RNA did not suppress ROS generation in Cd-treated cells. These results indicate that Cd induces pancreatic β-cell death via an oxidative stress downstream-mediated JNK activation-triggered mitochondria-regulated apoptotic pathway.

Antidiabetic effects of pterosin A, a small-molecular-weight natural product, on diabetic mouse models

The therapeutic effect of pterosin A, a small-molecular-weight natural product, on diabetes was investigated. Pterosin A, administered orally for 4 weeks, effectively improved hyperglycemia and glucose intolerance in streptozotocin, high-fat diet-fed, and db/db diabetic mice. There were no adverse effects in normal or diabetic mice treated with pterosin A for 4 weeks. Pterosin A significantly reversed the increased serum insulin and insulin resistance (IR) in dexamethasone-IR mice and in db/db mice. Pterosin A significantly reversed the reduced muscle GLUT-4 translocation and the increased liver phosphoenolpyruvate carboxyl kinase (PEPCK) expression in diabetic mice. Pterosin A also significantly reversed the decreased phosphorylations of AMP-activated protein kinase (AMPK) and Akt in muscles of diabetic mice. The decreased AMPK phosphorylation and increased p38 phosphorylation in livers of db/db mice were effectively reversed by pterosin A. Pterosin A enhanced glucose uptake and AMPK phosphorylation in cultured human muscle cells. In cultured liver cells, pterosin A inhibited inducer-enhanced PEPCK expression, triggered the phosphorylations of AMPK, acetyl CoA carboxylase, and glycogen synthase kinase-3, decreased glycogen synthase phosphorylation, and increased the intracellular glycogen level. These findings indicate that pterosin A may be a potential therapeutic option for diabetes.

High NH(4)(+)-N concentration wastewater treatment by shortcut nitrification-denitrification using a system of A/O inner loop fluidized bed biofilm reactors

In this experiment, a rapid mass-transfer inner loop fluidized bed biofilm reactor (ILFBBR) was employed to treat synthetic high ammonia nitrogen-containing (NH(4)(+)-N) wastewater by shortcut nitrification-denitrification. The reactor operation was stable after a short start-up period. Ammonia oxidizing bacteria (AOB) were predominant and 65% nitrite (NO(2)(-)-N/NO(x)(-)-N) levels were achieved. During the nitrification-denitrification period, the removal rates of NH(4)(+)-N and total nitrogen (TN) reached 94 and 82%, respectively. From the material balance, it was indicated that 87% of NH(4)(+)-N was removed by shortcut nitrification. The features of ILFBBR and the benefits of shortcut nitrification were combined in this experiment, and showed an excellent removal of NH(4)(+)-N from high-concentration NH(4)(+)-N wastewater.

Mercuric compounds induce pancreatic islets dysfunction and apoptosis in vivo

Mercury is a toxic heavy metal that is an environmental and industrial pollutant throughout the world. Mercury exposure leads to many physiopathological injuries in mammals. However, the precise toxicological effects of mercury on pancreatic islets in vivo are still unclear. Here, we investigated whether mercuric compounds can induce dysfunction and damage in the pancreatic islets of mice, as well as the possible mechanisms involved in this process. Mice were treated with methyl mercuric chloride (MeHgCl, 2 mg/kg) and mercuric chloride (HgCl₂, 5 mg/kg) for more than 2 consecutive weeks. Our results showed that the blood glucose levels increased and plasma insulin secretions decreased in the mice as a consequence of their exposure. A significant number of TUNEL-positive cells were revealed in the islets of mice that were treated with mercury for 2 consecutive weeks, which was accompanied by changes in the expression of the mRNA of anti-apoptotic (Bcl-2, Mcl-1, and Mdm-2) and apoptotic (p53, caspase-3, and caspase-7) genes. Moreover, plasma malondialdehyde (MDA) levels increased significantly in the mice after treatment with mercuric compounds for 2 consecutive weeks, and the generation of reactive oxygen species (ROS) in the pancreatic islets also markedly increased. In addition, the mRNA expression of genes related to antioxidation, including Nrf2, GPx, and NQO1, were also significantly reduced in these islets. These results indicate that oxidative stress injuries that are induced by mercuric compounds can cause pancreatic islets dysfunction and apoptosis in vivo.

Krüppel-like factor 4, a tumor suppressor in hepatocellular carcinoma cells reverts epithelial mesenchymal transition by suppressing slug expression

Krüppel-like factor 4 (KLF4) is a zinc-finger transcription factor that plays an important role in differentiation and pathogenesis. KLF4 has been suggested to act as an oncogene or tumor suppressor in different tumor types. However, the role of KLF4 in hepatocellular carcinoma (HCC) remains unclear. Here, we demonstrate that forced expression of Klf4 in murine HCC cell lines reduced anchorage-independent growth in soft agar as well as cell migration and invasion activities in vitro. Ectopic Klf4 expression impaired subcutaneous tumor growth and lung colonization in vivo. By contrast, Klf4 knockdown enhanced HCC cell migration. Interestingly, ectopic expression of Klf4 changed the morphology of murine HCC cells to a more epithelial phenotype. Associated with this, we found that expression of Slug, a critical epithelial mesenchymal transition (EMT)-related transcription factor, was significantly down-regulated in Klf4-expressing cells. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays showed that Klf4 is able to bind and repress the activity of the Slug promoter. Furthermore, ectopic Slug expression partially reverts the Klf4-mediated phenotypes. Consistent with a role as a tumor suppressor in HCC, analysis of the public microarray databases from Oncomine revealed reduced KLF4 expression in human HCC tissues in comparison with normal liver tissues in 3 out of 4 data sets. By quantitative reverse transcription-polymerase chain reaction (qRT-PCR), we found reduced KLF4 mRNA in 50% of HCC tissues. Importantly, an inverse correlation between the expression of KLF4 and SLUG was found in HCC tissues. Our data suggest that KLF4 acts as a tumor suppressor in HCC cells, in part by suppressing SLUG transcription.

A cascade of anoxic and oxic fluidized bed biofilm reactors for treatment of synthetic municipal wastewater

In this study, a cascade of anoxic and oxic fluidized bed biofilm reactors system was carried out to treat synthetic municipal wastewater. The parameters of the influent flow rates and C/N ratios were discussed. System performance was acceptable for chemical oxygen demand (COD), ammonia, and total nitrogen removal. A decrease of ammonia and total nitrogen removal efficiencies, however, was observed when the influent flow rates increased to 5.04 and 6.12 1 h(-1). Total nitrogen removal decreased at the influent C/N ratio of 3:1. The measured ratios of COD reduction in the anoxic column to nitrogen removal through nitrification-denitrification were 3.7, 3.5, 3.3, and 3.1 g COD/g(-1) N on average when the influent C/N ratios changed from 6:1 to 3:1. The observed sludge yield (Yobs) was 0.169 g VSS g COD(-1) because of perfect denitrification in the anoxic column and the relatively long solids retention time.

Abstract C42: p16-enhanced the migration phenotypes in hepatocellular carcinoma cells is Rb-independent

The occurrence of tumor metastasis to the extra-hepatic region contributes to a poor prognosis of hepatocellular carcinoma (HCC). However, the molecular mechanisms of metastasis in HCC remain unclear. Our previous studies showed that concomitant loss of Ink4a/Arf locus accelerated tumor formation and metastasis in mice with liver specific Trp53 deletion, indicating roles of Ink4a/Arf locus in tumorigenesis and metastasis. In this study, we focus on the p16 (Ink4a), a well-known tumor suppressor in regulation of cell cycle. When re-introduction of p16 into Trp53 and Ink4a/Arf-null liver cancer cells, we unexpectedly observed that p16 could enhance cell migration in HCC cell lines, including murine and human orgins by transwell assay and ectopic p16 expression also increased colonization in the lungs via tail vein injection into immune-deficient mice. Interestingly, there was no significant change in expression of epithelial mesenchymal transition (EMT)-related proteins. We further demonstrated that activity of Cdc42 and Rac1 was increased in MM189 cell with p16 over-expression but activity of RhoA was partially decreased. By knockdown of small GTPase, Cdc42 GTPase was required for p16-enhanced cell migration, whereas the related RhoA GTPase inhibited p16-mediated migration. Analysis of p16 mutants indicated that the Cdk4 interacting domain was required for stimulation of HCC cell migration, knockdown of Cdk4 and Cdk6 showed that these proteins are dispensable for this phenomenon. We therefore hypothesized that p16-mediated migration is not involved in pRb-dependent pathways. To validate our hypothesis, knockdown of pRb did not impair p16-enhanced migration in HepG2 cells with ectopic p16 expression. Our study suggested that p16-enhanced migration is not mediated by pRb-dependent pathways and more studies needs to be performed to elucidate this.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C42.

Mechanisms for the control of matriptase activity in the absence of sufficient HAI-1

Matriptase proteolytic activity must be tightly controlled for normal placental development, epidermal function, and epithelial integrity. Although hepatocyte growth factor activator inhibitor-1 (HAI-1) represents the predominant endogenous inhibitor for matriptase and the protein molar ratio of HAI-1 to matriptase is determined to be >10 in epithelial cells and the majority of carcinoma cells, an inverse HAI-1-to-matriptase ratio is seen in some ovarian and hematopoietic cancer cells. In the current study, cells with insufficient HAI-1 are investigated for the mechanisms through which the activity of matriptase is regulated. When matriptase activation is robustly induced in these cells, activated matriptase rapidly forms two complexes of 100- and 140-kDa in addition to the canonical 120-kDa matriptase-HAI-1 complex already described. Both 100- and 140-kDa complexes contain two-chain, cleaved matriptase but are devoid of gelatinolytic activity. Further biochemical characterization shows that the 140-kDa complex is a matriptase homodimer and that the 100-kDa complexes appear to contain reversible, tight binding serine protease inhibitor(s). The formation of the 140-kDa matriptase dimer is strongly associated with matriptase activation, and its levels are inversely correlated with the ratio of HAI-1 to matriptase. Given these observations and the likelihood that autoactivation requires the interaction of two matriptase molecules, it seems plausible that this activated matriptase homodimer may represent a matriptase autoactivation intermediate and that its accumulation may serve as a mechanism to control matriptase activity when protease inhibitor levels are limiting. These data suggest that matriptase activity can be rapidly inhibited by HAI-1 and other HAI-1-like protease inhibitors and "locked" in an inactive autoactivation intermediate, all of which places matriptase under very tight control.

Targeting zymogen activation to control the matriptase-prostasin proteolytic cascade

Membrane-associated serine protease matriptase has been implicated in human diseases and might be a drug target. In the present study, a novel class of matriptase inhibitors targeting zymogen activation is developed by a combination of the screening of compound library using a cell-based matriptase activation assay and a computer-aided search of commercially available analogues of a selected compound. Four structurally related compounds are identified that can inhibit matriptase activation with IC(50) at low micromolar concentration in both intact-cell and cell-free systems, suggesting that these inhibitors target the matriptase autoactivation machinery rather than the intracellular signaling pathways. These activation inhibitors can also inhibit prostasin activation, a downstream event that occurs in lockstep with matriptase activation. In contrast, the matriptase catalytic inhibitor CVS-3983 at a concentration 300-fold higher than its K(i) fails to inhibit activation of either protease. Our results suggest that inhibiting matriptase activation is an efficient way to control matriptase function.

Matriptase is inhibited by extravascular antithrombin in epithelial cells but not in most carcinoma cells

Antithrombin, a major anticoagulant, is robustly transported into extravascular compartments where its target proteases are largely unknown. This serpin was previously detected in human milk as complexes with matriptase, a membrane-bound serine protease broadly expressed in epithelial and carcinoma cells, and under tight regulation by hepatocyte growth factor activator inhibitor (HAI)-1, a transmembrane Kunitz-type serine protease inhibitor that forms heat-sensitive complexes with active matriptase. In the current study, we detect, in addition to matriptase-HAI-1 complexes, heat-resistant matriptase complexes generated by nontransformed mammary, prostate, and epidermal epithelial cells that we show to be matriptase-antithrombin complexes. These findings suggest that in addition to HAI-1, interstitial antithrombin participates in the regulation of matriptase activity in epithelial cells. This physiological mechanism appears, however, to largely be lost in cancer cells since matriptase-antithrombin complexes were not detected in all but two of a panel of seven breast, prostate, and ovarian cancer cell lines. Using purified active matriptase, we further characterize the formation of matriptase-antithrombin complex and show that heparin can significantly potentiate the inhibitory potency of antithrombin against matriptase. Second-order rate constants for the inhibition were determined to be 3.9 × 10(3) M(-1)s(-1) in the absence of heparin and 1.2 × 10(5) M(-1)s(-1) in the presence of heparin, a 30-fold increase, consistent with the established role of heparin in activating antithrombin function. Taken together these data suggest that normal epithelial cells employ a dual mechanism involving HAI-1 and antithrombin to control matriptase and that the antithrombin-based mechanism appears lost in the majority of carcinoma cells.

Effectiveness of bacterial disinfectants on surfaces of mechanical ventilator systems

BACKGROUND

Pathogens in healthcare settings can be transmitted via skin contact and environmental media. This study investigates bacterial contamination rate on surfaces of mechanical ventilator systems and bedside equipment. An experimental study evaluates the effectiveness of 75% alcohol in killing bacteria on surfaces.

METHODS

Surface swab sampling was conducted on ventilator systems and patient bedside equipment for detection of bacterial contamination. Surfaces of ventilator systems, such as faceplates, Y-pieces, and water traps, were swab sampled at 0.5, 8, and 24 hours after initial disinfection using a solution containing 0.5% sodium hypochlorite and pasteurization. The 75% alcohol aerosol was sprayed on the surfaces of faceplates, Y-pieces, and water traps on ventilator systems at 24 hours after initial disinfection, and then bacterial levels on the surfaces were evaluated.

RESULTS

Detection rates of Staphylococcus aureus were measured on the handrails of mechanical ventilators (64.7%), Y-pieces of breathing circuits (86.7%), and resuscitators (60.0%). Pseudomonas aeruginosa was identified on the surfaces of Y-pieces (6.7%) and water traps (13.3%) of breathing circuits, and also on suction systems (6.7%) and resuscitators (13.3%). The positive rate for total bacterial count was clearly increased on the surfaces of faceplates, Y-pieces, and water traps at 8 hour following disinfection by 0.5% sodium hypochlorite solution and pasteurization. Concentrations of S. aureus on surfaces decreased following treatment with 75% alcohol. However, considerable P. aeruginosa growth on water trap surfaces was observed after treatment with 75% alcohol.

CONCLUSIONS

The surfaces of ventilator systems, including faceplates, Y-pieces, and water traps, must be disinfected frequently (at least every 8 h) to control bacterial growth. Disinfection using 75% alcohol spray with air drying effectively decreased S. aureus on ventilator system surfaces.

Large-scale growth of Cu2ZnSnSe4 and Cu2ZnSnSe4/Cu2ZnSnS4 core/shell nanowires

We present a fast and simple protocol for large-scale preparation of quaternary Cu(2)ZnSnSe(4) (CZTSe), as well as CZTSe/Cu(2)ZnSnS(4) (CZTS) core/shell nanowires using CuSe nanowire bundles as self-sacrificial templates. CuSe nanowire bundles were synthesized by reacting Cu(2 - x)Se nanowire bundles with sodium citrate solution. CZTSe nanowires were prepared by reacting CuSe nanowire bundles with Zn(CH(3)COO)(2) and SnCl(2) in triethylene glycol. X-ray diffraction (XRD) and selected area electron diffraction studies show that stannite CZTSe is formed. The formed CZTSe nanowire bundles have diameters of 200-400 nm and lengths of up to hundreds of micrometers. CZTSe/CZTS nanocable bundles with similar morphologies were grown by the addition of some elemental sulfur to the reaction system for growth of CZTSe bundles. The stannite CZTSe/kesterite CZTS core/shell structure of the grown nanocables was confirmed by XRD and high-resolution transmission electron microscope investigation. The influence of S/Se molar ratio in the reaction system on the crystallographic structures and optical properties of CZTSe/CZTS nanocables was studied. The obtained CZTSe/CZTS core/shell nanocable bundles show broad and enhanced optical absorption over the visible and near-infrared region, which is promising for use in photovoltaic applications.

Involvement of oxidative stress-mediated ERK1/2 and p38 activation regulated mitochondria-dependent apoptotic signals in methylmercury-induced neuronal cell injury

Methylmercury (MeHg) is well-known for causing irreversible damage in the central nervous system as well as a risk factor for inducing neuronal degeneration. However, the molecular mechanisms of MeHg-induced neurotoxicity remain unclear. Here, we investigated the effects and possible mechanisms of MeHg in the mouse cerebrum (in vivo) and in cultured Neuro-2a cells (in vitro). In vivo study showed that the levels of LPO in the plasma and cerebral cortex significantly increased after administration of MeHg (50μg/kg/day) for 7 consecutive weeks. MeHg could also decrease glutathione level and increase the expressions of caspase-3, -7, and -9, accompanied by Bcl-2 down-regulation and up-regulation of Bax, Bak, and p53. Moreover, treatment of Neuro-2a cells with MeHg significantly reduced cell viability, increased oxidative stress damage, and induced several features of mitochondria-dependent apoptotic signals, including increased sub-G1 hypodiploids, mitochondrial dysfunctions, and the activation of PARP, and caspase cascades. These MeHg-induced apoptotic-related signals could be remarkably reversed by antioxidant NAC. MeHg also increased the phosphorylation of ERK1/2 and p38, but not JNK. Pharmacological inhibitors NAC, PD98059, and SB203580 attenuated MeHg-induced cytotoxicity, ERK1/2 and p38 activation, MMP loss, and caspase-3 activation in Neuro-2a cells. Taken together, these results suggest that the signals of ROS-mediated ERK1/2 and p38 activation regulated mitochondria-dependent apoptotic pathways that are involved in MeHg-induced neurotoxicity.

Abstract 291: Evaluation of blood flow in hepatocellular carcinoma: Assessment with computed tomography perfusion parameters and circulating angiogenic factors

Purpose: To study the relationships between CT perfusion parameters and circulating angiogenic factors in patients with hepatocellular carcinoma (HCC)

Materials and Methods: This study was HIPAA compliant and was approved by the institutional review board. All participants provided informed consents. CT perfusion parameters of HCCs among 21 patients were assessed using 21-phase liver images at a 64-slice multidetector CT. We analyzed CT perfusion parameters including total blood flow, arterial blood flow, portal blood flow and arterial fraction (arterial blood flow /total blood flow) of HCCs, surrounding liver parenchyma and HCC-parenchyma ratio. Interleukin 6 (IL-6), interleukin 8 (IL-8), vascular endothelial growth factor (VEGF), and platelet derived growth factor (PDGF) in plasma were measured using Bio-Plex multiplex immunoassay in 21 HCC patients and 8 healthy controls.

Result: CT perfusion parameters of HCCs showed statistically different from that of surrounding liver parenchyma in total blood flow (p=0.002), portal blood flow (p&lt;0.001) and arterial fraction (p&lt;0.001). Circulating IL-6, IL-8 and VEGF showed significantly higher levels in HCC patients than controls (p&lt;0.05), and predicted HCC significantly better than chance (p&lt;0.001). None of circulating angiogenic factors had significant correlation with any of CT perfusion parameters in HCC patients. Only HCC-parenchyma ratio of arterial blood flow showed significant positive correlation with circulating IL-8 (p&lt;0.05).

Conclusion: CT perfusion parameters of HCC and circulating angiogenic factors are useful tools for HCC diagnosis. Only circulating IL-8 and HCC-parenchyma ratio of arterial blood flow showed significant correlation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 291. doi:10.1158/1538-7445.AM2011-291

Protocols for use of homologous recombination gene targeting to produce microRNA mutants in Drosophila

MicroRNAs (miRNAs) are noncoding RNA molecules that have come to attract considerable interest for their roles in animal and plant development and disease. One means to study miRNA function in animal development is to create mutations. Use of gene-targeting strategies based on ends-out homologous recombination is a useful approach to produce mutations of desired structure, and is gaining popularity for producing miRNA knockouts. Here we present a detailed protocol for miRNA gene targeting and for their subsequent molecular characterization as well as confirmation by rescue. The descriptions of a series of modified vectors designed to facilitate the analysis of miRNA function are included, and a method to manipulate the mutant genome using recombinase-mediated cassette exchange.

Arsenic induces pancreatic β-cell apoptosis via the oxidative stress-regulated mitochondria-dependent and endoplasmic reticulum stress-triggered signaling pathways

Arsenic (As), a ubiquitous toxic metal, is an important environmental and industrial pollutant throughout the world. Inorganic As (iAs) is usually more harmful than organic ones and with a high risk of diabetes incidence by exposure. However, the toxicological effects of iAs on growth and function of pancreatic β-cells still remain unclear. Here, we found that iAs significantly decreased insulin secretion and cell viability, and increased ROS and MDA formation in pancreatic β-cell-derived RIN-m5F cells. iAs also induced the increases in sub-G1 hypodiploids, annexin V-Cy3 binding, and caspase-3 activity in RIN-m5F cells, indicating that iAs could induce β-cell apoptosis. Moreover, iAs induced MAPKs activation, mitochondria dysfunction, p53 up-regulation, Bcl-2 and Mdm-2 down-regulation, PARP, and caspase cascades, which displayed features of mitochondria-dependent apoptotic signals. In addition, exposure of RIN-m5F cells to iAs, could trigger ER stress as indicated by the enhancement in ER stress-related molecules induction (such as GRP78, GRP94, CHOP, and XBP1), procaspase-12 cleavage, and calpain activation. The iAs-induced apoptosis and its-related signalings could be effectively reversed by antioxidant N-acetylcysteine. We next observed that exposure of mice to iAs in drinking water for 6 consecutive weeks significantly decreased decreased the plasma insulin, elevated glucose intolerance and plasma lipid peroxidation, and induced islet cells apoptosis, which accompanied with arsenic accumulation in the whole blood and pancreas. N-acetylcysteine effectively antagonized the iAs-induced responses in mice. Taken together, these results suggest that iAs-induced oxidative stress causes pancreatic β-cells apoptosis via the mitochondria-dependent and ER stress-triggered signaling pathways.

Increased matriptase zymogen activation in inflammatory skin disorders

Matriptase, a type 2 transmembrane serine protease, and its inhibitor hepatocyte growth factor activator inhibitor (HAI)-1 are required for normal epidermal barrier function, and matriptase activity is tightly regulated during this process. We therefore hypothesized that this protease system might be deregulated in skin disease. To test this, we examined the level and activation state of matriptase in examples of 23 human skin disorders. We first examined matriptase and HAI-1 protein distribution in normal epidermis. Matriptase was detected at high levels at cell-cell junctions in the basal layer and spinous layers but was present at minimal levels in the granular layer. HAI-1 was distributed in a similar pattern, except that high-level expression was retained in the granular layer. This pattern of expression was retained in most skin disorders. We next examined the distribution of activated matriptase. Although activated matriptase is not detected in normal epidermis, a dramatic increase is seen in keratinocytes at the site of inflammation in 16 different skin diseases. To gain further evidence that activation is associated with inflammatory stimuli, we challenged HaCaT cells with acidic pH or H(2)O(2) and observed matriptase activation. These findings suggest that inflammation-associated reactive oxygen species and tissue acidity may enhance matriptase activation in some skin diseases.

Using mass spectrometry to detect buffalo salivary odorant-binding protein and its post-translational modifications

A large number of mammalian odorant-binding proteins, which are lipocalins, have been studied. These proteins participate in peri-receptor events by selecting and carrying odorant molecules. The present study aimed at identifying the buffalo salivary odorant-binding protein (sOBP), and to determine its post-translational modification using mass spectrometry. The buffalo salivary 21  kDa protein was initially separated adopting sodium dodecyl sulfate-polyacrylamide gel electrophoresis and it was identified as sOBP with high statistical reliability using liquid chromatography/tandem mass spectrometry (LC/MS/MS) and SEQUEST, for the first time. Further, the post-translationally modified peptides were screened adopting MS/MS. A total of four post-translational modifications, namely glycation at lysine-(59), hydroxylation at lysine-(134), ubiquitination at lysine-(121), and dihydroxylation in lysine-(108), were recorded. Moreover, these modifications have not been identified in buffalo salivary odorant-binding protein.

Heuristic optimization in penumbral image for high resolution reconstructed image

Penumbral imaging is a technique which uses the fact that spatial information can be recovered from the shadow or penumbra that an unknown source casts through a simple large circular aperture. The size of the penumbral image on the detector can be mathematically determined as its aperture size, object size, and magnification. Conventional reconstruction methods are very sensitive to noise. On the other hand, the heuristic reconstruction method is very tolerant of noise. However, the aperture size influences the accuracy and resolution of the reconstructed image. In this article, we propose the optimization of the aperture size for the neutron penumbral imaging.

Regulation of the matriptase-prostasin cell surface proteolytic cascade by hepatocyte growth factor activator inhibitor-1 during epidermal differentiation

Matriptase, a membrane-tethered serine protease, plays essential roles in epidermal differentiation and barrier function, largely mediated via its activation of prostasin, a glycosylphosphatidylinositol-anchored serine protease. Matriptase activity is tightly regulated by its inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1) such that free active matriptase is only briefly available to act on its substrates. In the current study we provide evidence for how matriptase activates prostasin under this tight control by HAI-1. When primary human keratinocytes are induced to differentiate in a skin organotypic culture model, both matriptase and prostasin are constitutively activated and then inhibited by HAI-1. These processes also occur in HaCaT human keratinocytes when matriptase activation is induced by exposure of the cells to a pH 6.0 buffer. Using this acid-inducible activation system we demonstrate that prostatin activation is suppressed by matriptase knockdown and by blocking matriptase activation with sodium chloride, suggesting that prostatin activation is dependent on matriptase in this system. Kinetics studies further reveal that the timing of autoactivation of matriptase, prostasin activation, and inhibition of both enzymes by HAI-1 binding are closely correlated. These data suggest that, during epidermal differentiation, the matriptase-prostasin proteolytic cascade is tightly regulated by two mechanisms: 1) prostasin activation temporally coupled to matriptase autoactivation and 2) HAI-1 rapidly inhibiting not only active matriptase but also active prostasin, resulting in an extremely brief window of opportunity for both active matriptase and active prostasin to act on their substrates.

Type I transglutaminase accumulation in the endoplasmic reticulum may be an underlying cause of autosomal recessive congenital ichthyosis

Type I transglutaminase (TG1) is an enzyme that is responsible for assembly of the keratinocyte cornified envelope. Although TG1 mutation is an underlying cause of autosomal recessive congenital ichthyosis, a debilitating skin disease, the pathogenic mechanism is not completely understood. In the present study we show that TG1 is an endoplasmic reticulum (ER) membrane-associated protein that is trafficked through the ER for ultimate delivery to the plasma membrane. Mutation severely attenuates this processing and a catalytically inactive point mutant, TG1-FLAG(C377A), accumulates in the endoplasmic reticulum and in aggresome-like structures where it is ubiquitinylated. This accumulation results from protein misfolding, as treatment with a chemical chaperone permits it to exit the endoplasmic reticulum and travel to the plasma membrane. ER accumulation is also observed for ichthyosis-associated TG1 mutants. Our findings suggest that misfolding of TG1 mutants leads to ubiquitinylation and accumulation in the ER and aggresomes, and that abnormal intracellular processing of TG1 mutants may be an underlying cause of ichthyosis.

Arsenic inhibits myogenic differentiation and muscle regeneration

BACKGROUND

The incidence of low birth weights is increased in offspring of women who are exposed to high concentrations of arsenic in drinking water compared with other women. We hypothesized that effects of arsenic on birth weight may be related to effects on myogenic differentiation.

OBJECTIVE

We investigated the effects of arsenic trioxide (As2O3) on the myogenic differentiation of myoblasts in vitro and muscle regeneration in vivo.

METHODS

C2C12 myoblasts and primary mouse and human myoblasts were cultured in differentiation media with or without As2O3 (0.1-0.5 microM) for 4 days. Myogenic differentiation was assessed by myogenin and myosin heavy chain expression and multinucleated myotube formation in vitro; skeletal muscle regeneration was tested using an in vivo mouse model with experimental glycerol myopathy.

RESULTS

A submicromolar concentration of As2O3 dose-dependently inhibited myogenic differentiation without apparent effects on cell viability. As2O3 significantly and dose-dependently decreased phosphorylation of Akt and p70s6k proteins during myogenic differentiation. As2O3-induced inhibition in myotube formation and muscle-specific protein expression was reversed by transfection with the constitutively active form of Akt. Sections of soleus muscles stained with hematoxylin and eosin showed typical changes of injury and regeneration after local glycerol injection in mice. Regeneration of glycerol-injured soleus muscles, myogenin expression, and Akt phosphorylation were suppressed in muscles isolated from As2O3-treated mice compared with untreated mice.

CONCLUSION

Our results suggest that As2O3 inhibits myogenic differentiation by inhibiting Akt-regulated signaling.

Rescue of Drosophila Melanogaster l(2)35Aa lethality is only mediated by polypeptide GalNAc-transferase pgant35A, but not by the evolutionary conserved human ortholog GalNAc-transferase-T11

The Drosophila l(2)35Aa gene encodes a UDP-N-acetylgalactosamine: Polypeptide N-acetylgalactosaminyltransferase, essential for embryogenesis and development (J. Biol. Chem. 277, 22623-22638; J. Biol. Chem. 277, 22616-22). l(2)35Aa, also known as pgant35A, is a member of a large evolutionarily conserved family of genes encoding polypeptide GalNAc-transferases. Phylogenetic and functional analyses have proposed that subfamilies of orthologous GalNAc-transferase genes are conserved in species, suggesting that they serve distinct functions in vivo. Based on sequence alignments, pgant35A and human GALNT11 are thought to belong to a distinct subfamily. Recent in vitro studies have shown that pgant35A and pgant7, encoding enzymes from different subfamilies, prefer different acceptor substrates, whereas the orthologous pgant35A and human GALNT11 gene products possess, 1) conserved substrate preferences and 2) similar acceptor site preferences in vitro. In line with the in vitro pgant7 studies, we show that l(2)35Aa lethality is not rescued by ectopic pgant7 expression. Remarkably and in contrast to this observation, the human pgant35A ortholog, GALNT11, was shown not to support rescue of the l(2)35Aa lethality. By use of genetic "domain swapping" experiments we demonstrate, that lack of rescue was not caused by inappropriate sub-cellular targeting of functionally active GalNAc-T11. Collectively our results show, that fly embryogenesis specifically requires functional pgant35A, and that the presence of this gene product during fly embryogenesis is functionally distinct from other Drosophila GalNAc-transferase isoforms and from the proposed human ortholog GALNT11.

Computational resources for protein modelling and drug discovery applications

The design of new medications is an intensive, time-consuming and costly process. Over the years, a rational approach that exploits the structural knowledge of a biological target has led to many successes. This procedure can be expedited using computer-aided modelling techniques. The structure-based approach to drug design relies on knowing the three-dimensional structure of the target macromolecule. If an experimental structure has not been determined yet, a good approximation of the protein target structure can be obtained through computational modelling, provided that some structures of its homologues are available to serve as templates. The vast majority of drugs currently on the market act by disrupting the interaction between a protein and its physiological ligand(s). Hence, once a molecular model is available, the next step is to identify and study its putative ligand-binding sites. Molecular "docking" may then be performed in silico to predict the modes of interaction between the ligand and the target. In this review, a list of computational resources for structure-based drug design has been compiled. It is hoped that readers who do not have much experiences will be equipped with the appropriate tools to make a first attempt at protein modelling and in silico ligand docking exercises.

TMPRSS2, a serine protease expressed in the prostate on the apical surface of luminal epithelial cells and released into semen in prostasomes, is misregulated in prostate cancer cells

TMPRSS2, a type II transmembrane serine protease, is highly expressed by the epithelium of the human prostate gland. To explore the regulation and function of TMPRSS2 in the prostate, a panel of monoclonal antibodies with high sensitivity and specificity were generated. Immunodetection showed TMPRSS2 on the apical plasma membrane of the prostate luminal cells and demonstrated its release into semen as a component of prostasomes, organelle-like vesicles that may facilitate sperm function and enhance male reproduction. In prostate cancer cells, TMPRSS2 expression was increased and the protein mislocalized over the entire tumor cell membrane. In both LNCaP prostate cancer cells and human semen, TMPRSS2 protein was detected predominantly as inactive zymogen forms as part of an array of multiple noncovalent and disulfide-linked complexes, suggesting that TMPRSS2 activity may be regulated by unconventional mechanisms. Our data suggested that TMPRSS2, an apical surface serine protease, may have a normal role in male reproduction as a component of prostasomes. The aberrant cellular localization, and increased expression of the protease seen in cancer, may contribute to prostate tumorigenesis by providing access of the enzyme to nonphysiological substrates and binding-proteins.

Polarized epithelial cells secrete matriptase as a consequence of zymogen activation and HAI-1-mediated inhibition

Matriptase, a transmembrane serine protease, is broadly expressed by, and crucial for the integrity of, the epithelium. Matriptase is synthesized as a zymogen and undergoes autoactivation to become an active protease that is immediately inhibited by, and forms complexes with, hepatocyte growth factor activator inhibitor (HAI-1). To investigate where matriptase is activated and how it is secreted in vivo, we determined the expression and activation status of matriptase in seminal fluid and urine and the distribution and subcellular localization of the protease in the prostate and kidney. The in vivo studies revealed that while the latent matriptase is localized at the basolateral surface of the ductal epithelial cells of both organs, only matriptase-HAI-1 complexes and not latent matriptase are detected in the body fluids, suggesting that activation, inhibition, and transcytosis of matriptase would have to occur for the secretion of matriptase. These complicated processes involved in the in vivo secretion were also observed in polarized Caco-2 intestinal epithelial cells. The cells target latent matriptase to the basolateral plasma membrane where activation, inhibition, and secretion of matriptase appear to take place. However, a proportion of matriptase-HAI-1 complexes, but not the latent matriptase, appears to undergo transcytosis to the apical plasma membrane for secretion. When epithelial cells lose their polarity, they secrete both latent and activated matriptase. Although most epithelial cells retain very low levels of matriptase-HAI-1 complex by rapidly secreting the complex, gastric chief cells may activate matriptase and store matriptase-HAI-1 complexes in the pepsinogen-secretory granules, suggesting an intracellular activation and regulated secretion in these cells. Taken together, while zymogen activation and closely coupled HAI-1-mediated inhibition are common features for matriptase regulation, the cellular location of matriptase activation and inhibition, and the secretory route for matriptase-HAI-1 complex may vary along with the functional divergence of different epithelial cells.

Molecular and genetic characterisation of the SARS coronavirus auxiliary protein X1 in Drosophila

1. We have generated monoclonal antibodies against the SARS coronavirus (SARS-CoV) X1/3a protein (3a), which are suitable for western blotting, immunocytochemistry, and immunohistochemistry. 2. We have established and characterised an in-vivo 3a transgenic Drosophila model, and demonstrated its usefulness in studying SARS-CoV 3a gene function. 3. We validated our in-vivo findings on 3a gene function in mammalian Vero E6 cells. 4. Our findings raise the possibility of using ion channel blockers as a novel approach to suppress SARS-CoV-induced cell death.

In vitro study on the influence of strontium-doped calcium polyphosphate on the angiogenesis-related behaviors of HUVECs

Angiogenesis is of great importance in bone tissue engineering, and has gained large attention in the past decade. Strontium-doped calcium polyphosphate (SCPP) is a novel biodegradable material which has been proved to be able to promote in vivo angiogenesis during bone regeneration. An in vitro culture system was developed in the present work to examine its influence on angiogenesis-related behaviors of human umbilical vein endothelial cells (HUVECs), including cell adhesion, spreading, proliferation and migration. The effects of microtopography, chemical property and the ingredients in the degradation fluid (DF) on cell behaviors were discussed. The results showed that cells attached and spread better on SCPP scaffold than on calcium polyphosphate (CPP), which might partially result from the less rough surface of SCPP scaffold and the less hydrogel formed on the surface. In addition, cell proliferation was significantly improved when treated with SCPP DF compared with the treatment with CPP DF. Statistical analysis indicated that Sr(2+) in SCPP DF might be the main reason for the improved cell proliferation. Moreover, cell migration, another important step during angiogenesis, was evidently stimulated by SCPP DF. The improved in vivo angiogenesis by SCPP might be assigned to its better surface properties and strontium in the DF. This work also provides a new method for in vitro evaluation of biodegradable materials' potential effects on angiogenesis.

p19Arf inhibits the invasion of hepatocellular carcinoma cells by binding to C-terminal binding protein

The INK4A/ARF tumor suppressor locus is frequently inactivated in hepatocellular carcinoma (HCC), yet the consequences of this remain unknown. We recently described a HCC mouse model in which loss of the Ink4a/Arf locus accelerates the development of metastasis and enhances tumor cell migration and invasion in cell culture assays. We show here that knockdown of p19Arf in an HCC cell line increases invasion in cell culture assays. Furthermore, reintroduction of p19(Arf) into HCC cell lines lacking Ink4a/Arf inhibits tumor cell invasion, without affecting cell proliferation, or cell transformation as measured by soft agar colony formation. Inhibition of cell invasion by p19(Arf) was dependent on its C-terminal binding protein (CtBP) interaction domain but independent of Mdm2 binding and nucleolar localization. Indeed, RNA interference-mediated knockdown of CtBP1 or CtBP2 decreased cell invasion, and ectopic expression of CtBP2 enhanced tumor cell migration and invasion. Thus, our data indicate a novel role for the Arf tumor suppressor protein in regulating phenotypes associated with tumor progression and metastasis in HCC cells.

Zymogen activation, inhibition, and ectodomain shedding of matriptase

Matriptase is a member of an expanding group of type II transmembrane serine proteases. Recently, much has been learned about the biochemistry, cellular biology, normal tissue physiology, and human pathology of this protease, and of its inhibitor, termed the hepatocyte growth factor inhibitor-1 (HAI-1). This review examines the recent literature that has characterized the regulation of matriptase and HAI-1 with an emphasis on the molecular mechanisms governing its zymogen activation, inhibition by HAI-1, and ectodomain shedding.

Germinoma involving the basal ganglia in children

BACKGROUND

Germinoma originating in the basal ganglia is rare, and the majority of reported papers have been from Japan. In a collection of the first 500 cases of primary brain tumors in children in Taipei Veterans General Hospital, six pure germinomas with tissue diagnosis situated in this location.

MATERIALS AND METHODS

We reviewed the clinical features, neuroimaging studies, tumor markers, management, and outcome of these six patients.

RESULTS

All of them were boys. The median age of onset of symptoms was 9.7 years. They uniformly presented with hemiparesis. The average duration of symptoms before surgical management was 1 year. One patient had bilateral basal ganglia tumors. Serum beta-human chorionic gonadotropin levels was elevated (128 mIU/ml) in one patient. Longitudinal neuroimaging studies in four patients clearly showed that the tumor arose as a tiny lesion at the lenticular nucleus. Five patients had cysts within tumors. Five patients received partial, subtotal, to total resection. One patient had stereotactic biopsy of the tumors. Postoperative primary adjuvant therapies included radiotherapy, chemotherapy alone, and combined chemotherapy and radiotherapy. Five patients survived, and one patient died of radiation-induced sarcoma with median follow-up period of 13.7 years. Local recurrence was observed in all of three patients after solitary postoperative chemotherapy.

CONCLUSIONS

The lenticular nucleus is a significant locus for germinomas and can be bilateral. Although rarely reported in Western countries, it does exist in Taiwan as well. Treatment of germinomas in this specific location is similar to germinoma in other intracranial locations.

The alternative reading frame tumor suppressor antagonizes hypoxia-induced cancer cell migration via interaction with the COOH-terminal binding protein corepressor

The alternative reading frame (ARF) tumor suppressor exerts both p53-dependent and p53-independent activities critical to the prevention of cancer in mice and humans. Recent evidence from mouse models suggests that when p53 is absent, further loss of ARF can widen the tumor spectrum, and potentiate invasion and metastasis. A major target of the p53-independent activity of ARF is the COOH-terminal binding protein (CtBP) family of metabolically regulated transcriptional corepressors, which are degraded upon acute exposure to the ARF protein. CtBPs are activated under conditions of metabolic stress, such as hypoxia, to repress epithelial and proapoptotic genes, and can mediate hypoxia-induced migration of cancer cells. The possibility that ARF could suppress tumor cell migration as part of its p53-independent activities was thus explored. Small-interfering RNA (siRNA)-mediated knockdown of ARF in human lung carcinoma cells led to increased cell migration, especially during hypoxia, and this effect was blocked by concomitant treatment with CtBP2 siRNA. Introduction of ARF into p53 and ARF-null human colon cancer cells inhibited hypoxia-induced migration. Furthermore, overexpression of CtBP2 in ARF-expressing cells enhanced cell migration, and an ARF mutant defective in CtBP-family binding was impaired in its ability to inhibit cell migration induced by CtBP2. ARF depletion or CtBP2 overexpression was associated with decreased PTEN expression and activation of the phosphatidylinositol 3-kinase pathway, and a phosphatidylinositol 3-kinase inhibitor blocked CtBP2-mediated cell migration. Thus, ARF can suppress cell migration by antagonizing CtBP2 and the phosphatidylinositol 3-kinase pathway, and these data may explain the increased aggressiveness of ARF-null tumors in mouse models.

Loss of p53 and Ink4a/Arf cooperate in a cell autonomous fashion to induce metastasis of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. HCC patients frequently present with disease that has metastasized to other regions of the liver, the portal vein, lymph nodes, or lungs, leading to poor prognoses. Therefore, model systems that allow exploration of the molecular mechanisms underlying metastasis in this disease are greatly needed. We describe here a metastatic HCC model generated after the somatic introduction of the mouse polyoma virus middle T antigen to mice with liver-specific deletion of the Trp53 tumor suppressor locus and show the cell autonomous effect of p53 loss of function on HCC metastasis. We additionally find that cholangiocarcinoma also develops in these mice, and some tumors display features of both HCC and cholangiocarcinoma, suggestive of origin from liver progenitor cells. Concomitant loss of the Ink4a/Arf tumor suppressor locus accelerates tumor formation and metastasis, suggesting potential roles for the p16 and p19 tumor suppressors in this process. Significantly, tumor cell lines isolated from tumors lacking both Trp53 and Ink4a/Arf display enhanced invasion activity in vitro relative to those lacking Trp53 alone. Thus, our data illustrate a new model system amenable for the analysis of HCC metastasis.

Glycosphingolipids with extended sugar chain have specialized functions in development and behavior of Drosophila

Glycosphingolipids (GSL) are glycosylated polar lipids in cell membranes essential for development of vertebrates as well as Drosophila. Mutants that impair enzymes involved in biosynthesis of GSL sugar chains provide a means to assess the functions of the sugar chains in vivo. The Drosophila glycosyltransferases Egghead and Brainiac are responsible for the 2nd and 3rd steps of GSL sugar chain elongation. Mutants lacking these enzymes are lethal and the nature of the defects that occur has suggested that GSL might impact on signaling by the Notch and EGFR pathways. Here we report on characterization of enzymes involved in the 4th and 5th steps of GSL sugar chain elongation in vitro and explore the biological consequences of removing the enzymes involved in step 4 in vivo. Two beta4-N-Acetylgalactosyltransferase enzymes can carry out step 4 (beta4GalNAcTA and beta4GalNAcTB), and while they may have overlapping activity, the mutants produce distinct phenotypes. The beta4GalNAcTA mutant displays behavioral defects, which are also observed in viable brainiac mutants, suggesting that proper locomotion and coordination primarily depend on GSL elongation. beta4GalNAcTB mutant animal shows ventralization of ovarian follicle cells, which is caused by defective EGFR signaling between the oocyte and the dorsal follicle cells to specify dorsal fate. GSL sequentially elongated by Egh, Brn and beta4GalNAcTB in the oocyte contribute to this signaling pathway. Despite the similar enzymatic activity, we provide evidence that the two enzymes are not functionally redundant in vivo, but direct distinct developmental functions of GSL.