Elevated expression of Runx2 as a key parameter in the etiology of osteosarcoma

To understand the molecular etiology of osteosarcoma, we isolated and characterized a human osteosarcoma cell line (OS1). OS1 cells have high osteogenic potential in differentiation induction media. Molecular analysis reveals OS1 cells express the pocket protein pRB and the runt-related transcription factor Runx2. Strikingly, Runx2 is expressed at higher levels in OS1 cells than in human fetal osteoblasts. Both pRB and Runx2 have growth suppressive potential in osteoblasts and are key factors controlling competency for osteoblast differentiation. The high levels of Runx2 clearly suggest osteosarcomas may form from committed osteoblasts that have bypassed growth restrictions normally imposed by Runx2. Interestingly, OS1 cells do not exhibit p53 expression and thus lack a functional p53/p21 DNA damage response pathway as has been observed for other osteosarcoma cell types. Absence of this pathway predicts genomic instability and/or vulnerability to secondary mutations that may counteract the anti-proliferative activity of Runx2 that is normally observed in osteoblasts. We conclude OS1 cells provide a valuable cell culture model to examine molecular events that are responsible for the pathologic conversion of phenotypically normal osteoblast precursors into osteosarcoma cells.

The role of pea3 group transcription factors in esophageal squamous cell carcinoma.

The transcription factors Pea3, Erm, and Er81 can promote cancer initiation and progression in various types of solid tumors. However, their role in esophageal squamous cell carcinoma (ESCC) has not been elucidated. In this study, we found that the expression levels of Pea3 and Erm, but not that of Er81, were significantly higher in ESCC compared with nontumor esophageal epithelium. A high level of Pea3 expression was significantly correlated with a shorter overall survival in a cohort of 81 patients with ESCC and the subgroup with N1 stage tumor (Wilcoxon-Gehan test, P = 0.016 and P = 0.001, respectively). Pea3 was overexpressed in seven ESCC cell lines compared with two immortalized esophageal cell lines. Pea3 knockdown reduced cell proliferation and suppressed nonadherent growth, migration, and invasion in ESCC cells in vitro. In addition, Pea3 knockdown in ESCC cells resulted in a down-regulation of phospho-Akt and matrix metalloproteinase 13, whereas a significant positive correlation in the expression levels was observed between Pea3 and phospho-Akt (r = 0.281, P

In Silico Prediction of the Mechanobiological Response of Arterial Tissue: Application to Angioplasty and Stenting

One way to restore physiological blood flow to occluded arteries involves the deformation of plaque using an intravascular balloon and preventing elastic recoil using a stent. Angioplasty and stent implantation cause unphysiological loading of the arterial tissue, which may lead to tissue in-growth and reblockage; termed “restenosis.” In this paper, a computational methodology for predicting the time-course of restenosis is presented. Stress-induced damage, computed using a remaining life approach, stimulates inflammation (production of matrix degrading factors and growth stimuli). This, in turn, induces a change in smooth muscle cell phenotype from contractile (as exists in the quiescent tissue) to synthetic (as exists in the growing tissue). In this paper, smooth muscle cell activity (migration, proliferation, and differentiation) is simulated in a lattice using a stochastic approach to model individual cell activity. The inflammation equations are examined under simplified loading cases. The mechanobiological parameters of the model were estimated by calibrating the model response to the results of a balloon angioplasty study in humans. The simulation method was then used to simulate restenosis in a two dimensional model of a stented artery. Cell activity predictions were similar to those observed during neointimal hyperplasia, culminating in the growth of restenosis. Similar to experiment, the amount of neointima produced increased with the degree of expansion of the stent, and this relationship was found to be highly dependant on the prescribed inflammatory response. It was found that the duration of inflammation affected the amount of restenosis produced, and that this effect was most pronounced with large stent expansions. In conclusion, the paper shows that the arterial tissue response to mechanical stimulation can be predicted using a stochastic cell modeling approach, and that the simulation captures features of restenosis development observed with real stents. The modeling approach is proposed for application in three dimensional models of cardiovascular stenting procedures.

Biogeographical conditions, the transition to agriculture and long-run growth

We use new data on the timing of the transition to agriculture, developed by Putterman and Trainor (2006), to test the theory of Diamond (1997) and Olsson and Hibbs (2005) that an earlier transition is reflected in higher incomes today. Our results confirm the theory, even after controlling for institutional quality and other geographical factors. The date of transition is correlated with prehistoric biogeography (the availability of wild grasses and large domesticable animal species). The factors conducive to high per capita incomes today are good institutions, an early transition to agriculture, access to the sea and a low incidence of fatal malaria. Geographical influences have been at work in all of these proximate determinants of per capita income.

Patient selection for oncology phase I trials: a multi-institutional study of prognostic factors.

PURPOSE The appropriate selection of patients for early clinical trials presents a major challenge. Previous analyses focusing on this problem were limited by small size and by interpractice heterogeneity. This study aims to define prognostic factors to guide risk-benefit assessments by using a large patient database from multiple phase I trials. PATIENTS AND METHODS Data were collected from 2,182 eligible patients treated in phase I trials between 2005 and 2007 in 14 European institutions. We derived and validated independent prognostic factors for 90-day mortality by using multivariate logistic regression analysis. Results The 90-day mortality was 16.5% with a drug-related death rate of 0.4%. Trial discontinuation within 3 weeks occurred in 14% of patients primarily because of disease progression. Eight different prognostic variables for 90-day mortality were validated: performance status (PS), albumin, lactate dehydrogenase, alkaline phosphatase, number of metastatic sites, clinical tumor growth rate, lymphocytes, and WBC. Two different models of prognostic scores for 90-day mortality were generated by using these factors, including or excluding PS; both achieved specificities of more than 85% and sensitivities of approximately 50% when using a score cutoff of 5 or higher. These models were not superior to the previously published Royal Marsden Hospital score in their ability to predict 90-day mortality. CONCLUSION Patient selection using any of these prognostic scores will reduce non-drug-related 90-day mortality among patients enrolled in phase I trials by 50%. However, this can be achieved only by an overall reduction in recruitment to phase I studies of 20%, more than half of whom would in fact have survived beyond 90 days.

Factors affecting in vitro adherence of ureteral stent biofilm isolates to polyurethane

Adherence of bacteria to biomaterials is the first stage in the development of a device-related infection. The adherence of bacterial cells to biomaterials may be influenced by surface characteristics of the cell, its growth conditions and the biomaterial surface chemistry. Following growth in human urine, the cell surface,hydrophobicity and zeta potential of two ureteral stent biofilm isolates, Enterococcus faecalis and Escherichia coli, were significantly altered. In addition, the adherence of human urine-grown Enterococcus faecalis and Escherichia coli to polyurethane was significantly increased by up to 52.1% and 58.6%, respectively. Treatment of the polyurethane with human urine rendered the polymer surface more hydrophilic (mean advancing water contact angle reduced from 97.59 degrees to 26.37 degrees). However, organisms grown in human urine showed less adherence (up to 90.4%) to the treated polymer than those grown in Mueller-Hinton broth. The results presented in this study indicate that in vivo conditions should be simulated as far as possible when carrying out in vitro bacterial adherence assays, especially if assessing novel methods for reduction of adherence. (C) 1997 Elsevier Science B.V.

FUS expression alters the differentiation response to all-trans retinoic acid in NB4 and NB4R2 cells

The FUS gene is overexpressed in acute myeloid leukaemia (AML) patients and has roles in transcription and mRNA processing. We used ectopic expression of FUS and FUS antisense sequences to assess the effect of modulation of FUS expression in all-trans retinoic acid (ATRA)-sensitive (NB4) and insensitive (NB4R2) human acute promyelocytic (APL) cell lines which express the t(15:17) translocation. Growth, viability and differentiation patterns were maintained, but the expression of the FUS antisense construct in both the cell lines altered the response to ATRA: the previously ATRA-sensitive NB4 cells exhibited resistance; whilst the previously resistant NB4R2 cells showed a differentiation response to treatment.

Growth-phase regulation of lipopolysaccharide O-antigen chain length influences serum resistance in serovars of Salmonella

The amount of lipopolysaccharide (LPS) O antigen (OAg) and its chain length distribution are important factors that protect bacteria from serum complement. Salmonella enterica serovar Typhi produces LPS with long chain length distribution (L-OAg) controlled by the wzz gene, whereas serovar Typhimurium produces LPS with two OAg chain lengths: an L-OAg controlled by Wzz(ST) and a very long (VL) OAg determined by Wzz(fepE). This study shows that serovar Enteritidis also has a bimodal OAg distribution with two preferred OAg chain lengths similar to serovar Typhimurium. It was reported previously that OAg production by S. Typhi increases at the late exponential and stationary phases of growth. The results of this study demonstrate that increased amounts of L-OAg produced by S. Typhi grown to stationary phase confer higher levels of bacterial resistance to human serum. Production of OAg by serovars Typhimurium and Enteritidis was also under growth-phase-dependent regulation; however, while the total amount of OAg increased during growth, the VL-OAg distribution remained constant. The VL-OAg distribution was primarily responsible for complement resistance, protecting the non-typhoidal serovars from the lytic action of serum irrespective of the growth phase. As a result, the non-typhoidal species were significantly more resistant than S. Typhi to human serum. When S. Typhi was transformed with a multicopy plasmid containing the S. Typhimurium wzz(fepE) gene, resistance to serum increased to levels comparable to the non-typhoidal serovars. In contrast to the relevant role for high-molecular-mass OAg molecules, the presence of Vi antigen did not contribute to serum resistance of clinical isolates of serovar Typhi.

MAP kinase pathway signalling is essential for extracellular matrix determined mammary epithelial cell survival

Mammary epithelial cells in primary cell culture require both growth factors and specific extracellular matrix (ECM)-attachment for survival. Here we demonstrate for the first time that inhibition of the ECM-induced Erk 1/Erk 2 (p42/44 MAPK) pathway, by PD 98059, leads to apoptosis in these cells. Associated with this cell death is a possible compensatory signalling through the p38 MAP kinase pathway the inhibition of which, by SB 203580, leads to a more rapid onset of apoptosis. This provides evidence for a hitherto undescribed Erk 1/Erk 2 to p38 MAP kinase pathway 'cross-talk' that is essential for the survival of these cells. The cell death associated with inhibition of these two MAP kinase pathways however, occurred in the presence of insulin that activates the classical PI-3 kinase-dependent Akt/PKB survival signals and Akt phosphorylation. Cell death induced by inhibition of the MAP kinase pathways did not affect Akt phosphorylation and may, thus, be independent of PI-3 kinase signalling.

Epidermal growth factor and phorbol myristate acetate increase expression of the mRNA for cytosolic phospholipase A2 in glomerular mesangial cells

We have previously shown that phospholipase A2 (PLA2) activity is rapidly activated by epidermal growth factor (EGF) and phorbol 12-myristate 13-acetate (PMA) in renal mesangial cells and other cell systems in a manner that suggests a covalent modification of the PLA2 enzyme(s). This PLA2 activity is cytosolic (cPLA2) and is distinct from secretory forms of PLA2, which are also stimulated in mesangial cells in response to cytokines and other agonists. However, longer-term regulation of cPLA2 in renal cells may also occur at the level of gene expression. Cultured rat mesangial cells were used as a model system to test the effects of EGF and PMA on the regulation of cPLA2 gene expression. EGF and PMA both produced sustained increases in cPLA2 mRNA levels, with a parallel increase in enzyme activity over time. Inhibition of protein synthesis by cycloheximide increased basal cPLA2 mRNA accumulation in serum-starved mesangial cells, and the combination of EGF and cycloheximide resulted in super-induction of cPLA2 gene expression compared with EGF alone. Actinomycin D treatment entirely abrogated the effect of EGF on cPLA2 mRNA accumulation. These findings suggest that regulation of cPLA2 is achieved by factors controlling gene transcription and possibly mRNA stability, in addition to previously characterized posttranslational modifications.

Transcriptional regulation of a brown adipocyte-specific gene, UCP1, by KLF11 and KLF15

Several growth factors and transcription factors have been reported to play important roles in brown adipocyte differentiation and modulation of thermogenic gene expression, especially the expression of UCP1. In this study, we focused on KLF11 and KLF15, which were expressed highly in brown adipose tissue. Our data demonstrated that KLF11 and KLF15 interacted directly with the UCP1 promoter using GC-box and GT-boxes, respectively. Co-transfection of KLF11 and KLF15 in the mesenchymal stem cell line muBM3.1 during brown adipocyte differentiation enhanced the expression level of UCP1. KLF11, but not KLF15, was essential for UCP1 expression during brown adipocyte differentiation of muBM3.1.

Neonatal pain in relation to postnatal growth in infants born very preterm

Procedural pain is associated with poorer neurodevelopment in infants born very preterm (= 32 weeks gestational age), however, the etiology is unclear. Animal studies have demonstrated that early environmental stress leads to slower postnatal growth; however, it is unknown whether neonatal pain-related stress affects postnatal growth in infants born very preterm. The aim of this study was to examine whether greater neonatal pain (number of skin-breaking procedures adjusted for medical confounders) is related to decreased postnatal growth (weight and head circumference [HC] percentiles) early in life and at term-equivalent age in infants born very preterm. Participants were n=78 preterm infants born = 32 weeks gestational age, followed prospectively since birth. Infants were weighed and HC measured at birth, early in life (median: 32 weeks [interquartile range 30.7-33.6]) and at term-equivalent age (40 weeks [interquartile range 38.6-42.6]). Weight and HC percentiles were computed from sex-specific British Columbia population-based data. Greater neonatal pain predicted lower body weight (Wald ?(2)=7.36, P=0.01) and HC (Wald ?(2)=4.36, P=0.04) percentiles at 32 weeks postconceptional age, after adjusting for birth weight percentile and postnatal risk factors of illness severity, duration of mechanical ventilation, infection, and morphine and corticosteroid exposure. However, later neonatal infection predicted lower weight percentile at term (Wald ?(2)=5.09, P=0.02). Infants born very preterm undergo repetitive procedural pain during a period of physiological immaturity that appears to impact postnatal growth, and may activate a downstream cascade of stress signaling that affects later growth in the neonatal intensive care unit.

Preterm cerebellar growth impairment after postnatal exposure to glucocorticoids

As survival rates of preterm newborns improve as a result of better medical management, these children increasingly show impaired cognition. These adverse cognitive outcomes are associated with decreases in the volume of the cerebellum. Because animals exhibit reduced preterm cerebellar growth after perinatal exposure to glucocorticoids, we sought to determine whether glucocorticoid exposure and other modifiable factors increased the risk for these adverse outcomes in human neonates. We studied 172 preterm neonatal infants from two medical centers, the University of British Columbia and the University of California, San Francisco, by performing serial magnetic resonance imaging examinations near birth and again near term-equivalent age. After we adjusted for associated clinical factors, antenatal betamethasone was not associated with changes in cerebellar volume. Postnatal exposure to clinically routine doses of hydrocortisone or dexamethasone was associated with impaired cerebellar, but not cerebral, growth. Alterations in treatment after preterm birth, particularly glucocorticoid exposure, may help to decrease risk for adverse neurological outcome after preterm birth.

Splicing of HDAC7 modulates the SRF-myocardin complex during stem-cell differentiation towards smooth muscle cells

Histone deacetylases (HDACs) have a central role in the regulation of gene expression. Here we investigated whether HDAC7 has an impact on embryonic stem (ES) cell differentiation into smooth muscle cells (SMCs). ES cells were seeded on collagen-IV-coated flasks and cultured in the absence of leukemia inhibitory factor in differentiation medium to induce SMC differentiation. Western blots and double-immunofluorescence staining demonstrated that HDAC7 has a parallel expression pattern with SMC marker genes. In ex vivo culture of embryonic cells from SM22-LacZ transgenic mice, overexpression of HDAC7 significantly increased beta-galactosidase-positive cell numbers and enzyme activity, indicating its crucial role in SMC differentiation during embryonic development. We found that HDAC7 undergoes alternative splicing during ES cell differentiation. Platelet-derived growth factor enhanced ES cell differentiation into SMCs through upregulation of HDAC7 splicing. Further experiments revealed that HDAC7 splicing induced SMC differentiation through modulation of the SRF-myocardin complex. These findings suggest that HDAC7 splicing is important for SMC differentiation and vessel formation in embryonic development.

HDAC3 is crucial in shear- and VEGF-induced stem cell differentiation toward endothelial cells

Reendothelialization involves endothelial progenitor cell (EPC) homing, proliferation, and differentiation, which may be influenced by fluid shear stress and local flow pattern. This study aims to elucidate the role of laminar flow on embryonic stem (ES) cell differentiation and the underlying mechanism. We demonstrated that laminar flow enhanced ES cell-derived progenitor cell proliferation and differentiation into endothelial cells (ECs). Laminar flow stabilized and activated histone deacetylase 3 (HDAC3) through the Flk-1-PI3K-Akt pathway, which in turn deacetylated p53, leading to p21 activation. A similar signal pathway was detected in vascular endothelial growth factor-induced EC differentiation. HDAC3 and p21 were detected in blood vessels during embryogenesis. Local transfer of ES cell-derived EPC incorporated into injured femoral artery and reduced neointima formation in a mouse model. These data suggest that shear stress is a key regulator for stem cell differentiation into EC, especially in EPC differentiation, which can be used for vascular repair, and that the Flk-1-PI3K-Akt-HDAC3-p53-p21 pathway is crucial in such a process.