bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transforming Growth Factor-β1 Induces Tissue Inhibitor of Metalloproteinase-1 Expression via Activation of Extracellular Signal-Regulated Kinase and Sp1 in Human Fibrosarcoma Cells
Authors: Kwak Hee-Jin , Park Myung-Jin , Cho Hyeyoung , Park Chang-Min , Moon Sang-Ik , Lee Hyung-Chan , Park In-Chul , Kim Mi-Suk , Rhee Chang Hun , Hong Seok-Il 
Published: March 2006

Abstract
The net balance of matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinases (TIMP) system has been known to be a key factor in tumor cell invasion. In the present study, we investigated the molecular mechanisms of anti-invasive and antimigrative activity of transforming growth factor (TGF)-β1 on HT1080 human fibrosarcoma cells. In in vitro Matrigel invasion and Transwell migration assays, TGF-β1 dose-dependently inhibited the invasion and migration of HT1080 cells, respectively. Gelatin zymography, Western blot, and real-time PCR analysis showed that TGF-β1 enhanced the expression and secretion of MMP-2, TIMP-1, and, to a lesser degree, MMP-9 but not membrane type 1-MMP and TIMP-2. The addition of recombinant TIMP-1 protein reduced the Matrigel invasion and Transwell migration of HT1080 cells, similar to TGF-β1. Because augmentation of TIMP-1 might be the major factor for the anti-invasive and antimigrative activity of TGF-β1, we investigated possible molecular mechanisms responsible for the expression of TIMP-1 induced by TGF-β1. Treatment of HT1080 cells with TGF-β1 rapidly phosphorylated three mitogen-activated protein kinases [MAPK; extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and c-Jun NH2-terminal kinase] and Akt. Among these kinases, the inhibition of only ERK1/2 pathway by PD98059, a specific inhibitor of MAPK/ERK kinase(MEK)-1, and transfection of dominant-negative MEK 1 effectively blocked the TIMP-1 induction by TGF-β1. Mithramycin, a specific inhibitor of Sp1 transcription factor, but not curcumin, an inhibitor of activator protein-1, and transfection of Sp1 small interfering RNA significantly inhibited the TGF-β1-induced expression of TIMP-1. In addition, electrophoretic mobility shift assay showed that TGF-β1 up-regulated Sp1 DNA-binding activity, and PD98059 and mithramycin effectively inhibited these events. Finally, pretreatment of HT1080 cells with PD98059 and mithramycin, but not curcumin, restored the invasive activity of these cells. Taken together, these data suggest that TGF-β1 modulates the net balance of the MMPs/TIMPs the systems in HT1080 cells for anti-invasion and antimigration by augmenting TIMP-1 through ERK1/2 pathway and Sp1 transcription factor. (Mol Cancer Res 2006;4(3):209–20)
ATM Requirement in Gene Expression Responses to Ionizing Radiation in Human Lymphoblasts and Fibroblasts
Authors: Innes Cynthia L. , Heinloth Alexandra N. , Flores Kristina G. , Sieber Stella O. , Deming Paula B. , Bushel Pierre R. , Kaufmann William K. , Paules Richard S. 
Published: March 2006

Abstract
The heritable disorder ataxia telangiectasia (AT) is caused by mutations in the AT-mutated (ATM) gene with manifestations that include predisposition to lymphoproliferative cancers and hypersensitivity to ionizing radiation (IR). We investigated gene expression changes in response to IR in human lymphoblasts and fibroblasts from seven normal and seven AT-affected individuals. Both cell types displayed ATM-dependent gene expression changes after IR, with some responses shared and some responses varying with cell type and dose. Interestingly, after 5 Gy IR, lymphoblasts displayed ATM-independent responses not seen in the fibroblasts at this dose, which likely reflect signaling through ATM-related kinases, e.g., ATR, in the absence of ATM function. (Mol Cancer Res 2006;4(3):197–207)
SSeCKS/Gravin/AKAP12 Metastasis Suppressor Inhibits Podosome Formation via RhoA- and Cdc42-Dependent Pathways
Authors: Gelman Irwin H. , Gao Lingqiu 
Published: March 2006

Abstract
Podosomes are poorly understood actin-rich structures notably found in cancer cell lines or in v-Src-transformed cells that are thought to facilitate some of the invasive properties involved in tumor metastasis. The enrichment of the Tks5/Fish protein, a v-Src substrate, is required for formation of podosomes. We showed previously that the tetracycline-regulated reexpression of the Src-suppressed C kinase substrate (SSeCKS, also known as Gravin/AKAP12) inhibited variables of v-Src-induced oncogenic growth in NIH3T3, correlating with the induction of normal actin cytoskeletal structures and cell morphology but not with gross inhibition of Src phosphorylation activity in the cell. Here, we show that SSeCKS reexpression at physiologic levels suppresses podosome formation, correlating with decreases in Matrigel invasiveness, whereas there is no effect on total cellular tyrosine phosphorylation or on the phosphorylation of Tks5/Fish. Activated forms of RhoA and Cdc42 were capable of rescuing podosome formation in v-Src cells reexpressing SSeCKS, and this correlated with the ability of SSeCKS to inhibit RhoA and Cdc42 activity levels by &gt;5-fold. Interestingly, although activated Rac I had little effect on podosome formation, it could partner with activated RhoA to reverse the cell flattening induced by SSeCKS. These data suggest that v-Src-induced Tks5 tyrosine phosphorylation is insufficient for podosome formation in the absence of RhoA- and/or Cdc42-mediated cytoskeletal remodeling. Additionally, they strengthen the notion that SSeCKS suppresses Src-induced oncogenesis by reestablishing actin-based cytoskeletal architecture. (Mol Cancer Res 2006;4(3):151–8)
Activation of Peroxisome Proliferator-Activated Receptor-γ Decreases Pancreatic Cancer Cell Invasion through Modulation of the Plasminogen Activator System
Authors: Sawai Hirozumi , Liu Joey , Reber Howard A. , Hines Oscar J. , Eibl Guido 
Published: March 2006

AbstractCancer cell invasion and metastasis require the concerted action of several proteases that degrade extracellular matrix proteins and basement membranes. Recent reports suggest the plasminogen activator system plays a critical role in pancreatic cancer biology. In the present study, we determined the contribution of the plasminogen activator system to pancreatic cancer cell invasion in vitro. Moreover, the effect of peroxisome proliferator-activated receptor (PPAR)-γ ligands, which are currently in clinical use as antidiabetic drugs and interestingly seem to display antitumor activities, on pancreatic cancer cell invasion and the plasminogen activator system was assessed. Expression of components of the plasminogen activator system [i.e., urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1, and uPA receptor] was detected in six human pancreatic cancer cell lines. Inhibition of urokinase activity by specific synthetic compounds reduced baseline pancreatic cancer cell invasion. The PPAR-γ ligands 15-deoxy-Δ12,14-prostaglandin J2 and ciglitazone also attenuated pancreatic cancer cell invasion. This effect was abrogated by dominant-negative PPAR-γ receptors and pharmacologic PPAR-γ inhibitors. Moreover, activation of PPAR-γ by ligands increased plasminogen activator inhibitor-1 and decreased uPA levels in pancreatic cancer cells, and this was accompanied by a reduction in total urokinase activity. The present study shows that the plasminogen activator system plays an integral role in pancreatic cancer cell invasion in vitro. Activation of the nuclear receptor PPAR-γ by ligands reduced pancreatic cancer cell invasion, which was largely mediated by modulation of the plasminogen activator system. These findings further underscore the potential role of PPAR-γ ligands as therapeutic agents in pancreatic cancer. (Mol Cancer Res 2006;4(3):159–67)
Association of Transforming Growth Factor-β1 Gene Polymorphisms With Myocardial Infarction in Patients With Angiographically Proven Coronary Heart Disease
Authors: Koch Werner , Hoppmann Petra , Mueller Jakob C. , Schömig Albert , Kastrati Adnan 
Published: March 2006

Objective—Transforming growth factor (TGF)-β1 (TGF-β1) is a multifunctional cytokine that exhibits vasculoprotective properties. Production and plasma levels of TGF-β1 are influenced by polymorphisms in the TGF-β1 gene (TGFB1). We investigated whether the −509C/T (rs1800469), 868T/C (rs1982073), 913G/C (rs1800471), and 11929C/T (rs1800472) polymorphisms ofTGFB1are associated with myocardial infarction.Methods and Results—The study population consisted of 3657 patients with myocardial infarction (885 women and 2772 men) and 1211 control individuals (598 women and 613 men) with angiographically normal coronary arteries and without signs or symptoms of myocardial infarction. Polymorphism-related genotypes were determined with TaqMan assays and haplotypes were estimated from the genotype data. The −509C/T polymorphism and −509C/868T/913G/11929C (CTGC) haplotype were associated with myocardial infarction in men, independently from the potentially confounding factors age, arterial hypertension, hypercholesterolemia, cigarette smoking, and diabetes mellitus. Lower risks of myocardial infarction were observed among the carriers of the −509CC genotype (adjusted odds ratio [OR], 0.49; 95% confidence interval [CI], 0.27 to 0.87;P=0.014) and homozygous carriers of the CTGC haplotype (adjusted OR, 0.61; 95% CI, 0.38 to 0.98;P=0.042) than among the noncarriers of this genotype or haplotype. None of the genotypes (P≥0.37) or haplotypes (P≥0.35) was associated with myocardial infarction in women.Conclusions—Positive association findings in this study suggest thatTGFB1is a susceptibility locus for myocardial infarction.
Mdm2 inhibitor Nutlin-3a induces p53-mediated apoptosis by transcription-dependent and transcription-independent mechanisms and may overcome Atm-mediated resistance to fludarabine in chronic lymphocytic leukemia
Authors: Kojima Kensuke , Konopleva Marina , McQueen Teresa , O'Brien Susan , Plunkett William , Andreeff Michael 
Published: March 2006

Abstract
Although TP53 mutations are rare in B-cell chronic lymphocytic leukemia (CLL), Mdm2 overexpression has been reported as an alternative cause of p53 dysfunction. We investigated the potential therapeutic use of nongenotoxic p53 activation by a small-molecule antagonist of Mdm2, Nutlin-3a, in CLL. Nutlin-3a induced significant apoptosis in 30 (91%) of 33 samples from previously untreated patients with CLL; all resistant samples had TP53 mutations. Low levels of Atm (ataxia telangiectasia mutated) or high levels of Mdm2 (murine double minute 2) did not prevent Nutlin-3a from inducing apoptosis. Nutlin-3a used transcription-dependent and transcription-independent pathways to induce p53-mediated apoptosis. Predominant activation of the transcription-independent pathway induced more pronounced apoptosis than that of the transcription-dependent pathway, suggesting that activation of the transcription-independent pathway is sufficient to initiate p53-mediated apoptosis in CLL. Combination treatment of Nutlin-3a and fludarabine synergistically increased p53 levels, and induced conformational change of Bax and apoptosis in wild-type p53 cells but not in cells with mutant p53. The synergistic apoptotic effect was maintained in samples with low Atm that were fludarabine resistant. Results suggest that the nongenotoxic activation of p53 by targeting the Mdm2-p53 interaction provides a novel therapeutic strategy for CLL.
Spermatogenesis in long-term survivors after allogeneic hematopoietic stem cell transplantation is associated with age, time interval since transplantation, and apparently absence of chronic GvHD
Authors: Rovó Alicia , Tichelli André , Passweg Jakob R. , Heim Dominik , Meyer-Monard Sandrine , Holzgreve Wolfgang , Gratwohl Alois , De Geyter Christian 
Published: March 2006

Abstract
Factors associated with spermatogenesis after allogeneic hematopoietic stem cell transplantation (HSCT) were assessed in this prospective, single-center, cross-sectional study. All consecutive men aged 18 years or older and in complete remission 2 years or longer after HSCT were invited to participate. Seminal fluid analysis was performed on freshly collected samples according to World Health Organization guidelines. Between April 2003 and June 2004, 39 patients were included. The median age at semen analysis was 34 years (range, 20-59 years), and the median time interval between HSCT and sperm analysis 9 years (range, 2-20 years). Thirty-two patients (82%) underwent total body irradiation (TBI; ≥ 10 Gy) as part of their conditioning regimen. Eleven of 39 (28%) patients showed some spermatogenesis. Patients with detectable spermatozoa in the ejaculate were younger at HSCT (median age, 19 versus 28 years; P = .004), had a longer interval since HSCT (median time, 12 versus 7 years; P = .01), and were more often without chronic graft-versus-host disease (GvHD; 2 of 11 patients versus 16 of 28; P = .03). Nine of 16 patients (56%) undergoing transplantation when younger than age 25 years showed some degree of spermatogenesis. In conclusion, men who are long-term survivors, who were younger than 25 years at HSCT, and who apparently do not have chronic GvHD have a reasonable likelihood of spermatogenesis even when conditioned with standard-dose TBI.
Role of urease in megasome formation and Helicobacter pylori survival in macrophages
Authors: Schwartz Justin T , Allen Lee-Ann H 
Published: March 2006

Abstract
Previous studies have demonstrated that Helicobacter pylori (Hp) delays its entry into macrophages and persists inside megasomes, which are poorly acidified and accumulate early endosome autoantigen 1. Herein, we explored the role of Hp urease in bacterial survival in murine peritoneal macrophages and J774 cells. Plasmid-free mutagenesis was used to replace ureA and ureB with cat in Hp Strains 11637 and 11916. ureAB null Hp lacked detectable urease activity and did not express UreA or UreB as judged by immunoblotting. Deletion of ureAB had no effect on Hp binding to macrophages or the rate or extent of phagocytosis. However, intracellular survival of mutant organisms was impaired significantly. Immunofluorescence microscopy demonstrated that (in contrast to parental organisms) mutant Hp resided in single phagosomes, which were acidic and accumulated the lysosome marker lysosome-associated membrane protein-1 but not early endosome autoantigen 1. A similar phenotype was observed for spontaneous urease mutants derived from Hp Strain 60190. Treatment of macrophages with bafilomycin A1, NH4Cl, or chloroquine prevented acidification of phagosomes containing mutant Hp. However, only ammonium chloride enhanced bacterial viability significantly. Rescue of ureAB null organisms was also achieved by surface adsorption of active urease. Altogether, our data indicate a role for urease and urease-derived ammonia in megasome formation and Hp survival.
Aggregated IgG inhibits the differentiation of human fibrocytes
Authors: Pilling Darrell , Tucker Nancy M , Gomer Richard H 
Published: March 2006

Abstract
Fibrocytes are fibroblast-like cells, which appear to participate in wound healing and are present in pathological lesions associated with asthma, pulmonary fibrosis, and scleroderma. Fibrocytes differentiate from CD14+ peripheral blood monocytes, and the presence of serum delays this process dramatically. We previously purified the factor in serum, which inhibits fibrocyte differentiation, and identified it as serum amyloid P (SAP). As SAP binds to Fc receptors for immunoglobulin G (IgG; FcγRs), FcγR activation may be an inhibitory signal for fibrocyte differentiation. FcγR are activated by aggregated IgG, and we find aggregated but not monomeric, human IgG inhibits human fibrocyte differentiation. Monoclonal antibodies that bind to FcγRI (CD64) or FcγRII (CD32) also inhibit fibrocyte differentiation. Aggregated IgG lacking Fc domains or aggregated IgA, IgE, or IgM do not inhibit fibrocyte differentiation. Incubation of monocytes with SAP or aggregated IgG inhibited fibrocyte differentiation. Using inhibitors of protein kinase enzymes, we show that Syk- and Src-related tyrosine kinases participate in the inhibition of fibrocyte differentiation. These observations suggest that fibrocyte differentiation can occur in situations where SAP and aggregated IgG levels are low, such as the resolution phase of inflammation.
Regulation of Insulin Gene Transcription by the Immediate-Early Growth Response Gene Egr-1
Authors: Eto Kazuhiro , Kaur Varinderpal , Thomas Melissa K. 
Published: March 2006

AbstractChanges in extracellular glucose levels regulate the expression of the immediate-early response gene and zinc finger transcription factor early growth response-1 (Egr-1) in insulin-producing pancreatic β-cells, but key target genes of Egr-1 in the endocrine pancreas have not been identified. We found that overexpression of Egr-1 in clonal (INS-1) β-cells increased transcriptional activation of the rat insulin I promoter. In contrast, reductions in Egr-1 expression levels or function with the introduction of either small interfering RNA targeted to Egr-1 (siEgr-1) or a dominant-negative form of Egr-1 decreased insulin promoter activation, and siEgr-1 suppressed insulin gene expression. Egr-1 did not directly interact with insulin promoter sequences, and mutagenesis of a potential G box recognition sequence for Egr-1 did not impair the Egr-1 responsiveness of the insulin promoter, suggesting that regulation of insulin gene expression by Egr-1 is probably mediated through additional transcription factors. Overexpression of Egr-1 increased, and reduction of Egr-1 expression decreased, transcriptional activation of the glucose-responsive FarFlat minienhancer within the rat insulin I promoter despite the absence of demonstrable Egr-1-binding activity to FarFlat sequences. Notably, augmenting Egr-1 expression levels in insulin-producing cells increased the mRNA and protein expression levels of pancreas duodenum homeobox-1 (PDX-1), a major transcriptional regulator of glucose-responsive activation of the insulin gene. Increasing Egr-1 expression levels enhanced PDX-1 binding to insulin promoter sequences, whereas mutagenesis of PDX-1-binding sites reduced the capacity of Egr-1 to activate the insulin promoter. We propose that changes in Egr-1 expression levels in response to extracellular signals, including glucose, can regulate PDX-1 expression and insulin production in pancreatic β-cells.
Mammalian K-ras2 Is a Corticosteroid-Induced Gene in Vivo
Authors: Brennan Francine E. , Fuller Peter J. 
Published: March 2006

Abstract
Aldosterone acts via the mineralocorticoid receptor to regulate gene expression. A number of aldosterone-induced genes have been characterized in the distal colon and/or the distal nephron. Using the Xenopus kidney-derived A6 cell line, the K-ras transcript of the K-ras gene was identified as aldosterone induced, with a role in epithelial sodium transport. This study sought to establish whether K-ras expression is also increased in mammalian epithelia in vivo in response to aldosterone. RNA was extracted from the kidney and distal colon of rats treated with aldosterone or dexamethasone. Northern blot analysis and real-time RT-PCR were performed using probes and primers specific for the K-rasA isoform and for total K-ras. The expression of both total K-ras and of the A isoform is induced in the distal colon by aldosterone and by dexamethasone. Given the relative abundances of the two isoforms, this would appear to indicate induction of both isoforms. The time course of the response is consistent with a primary transcriptional response. In contrast to the documented up-regulation in the amphibian kidney, we did not observe regulation by corticosteroids in the kidney. However, regulation in a subpopulation of cells cannot be excluded.
Paracrine and Autocrine Regulation of Epidermal Growth Factor-Like Factors in Cumulus Oocyte Complexes and Granulosa Cells: Key Roles for Prostaglandin Synthase 2 and Progesterone Receptor
Authors: Shimada Masayuki , Hernandez-Gonzalez Inmaculada , Gonzalez-Robayna Ignacio , Richards JoAnne S. 
Published: March 2006

AbstractThe molecular bridges that link the LH surge with functional changes in cumulus cells that possess few LH receptors are being unraveled. Herein we document that epidermal growth factor (EGF)-like factors amphiregulin (Areg), epiregulin (Ereg), and betacellulin (Btc) are induced in cumulus oocyte complexes (COCs) by autocrine and paracrine mechanisms that involve the actions of prostaglandins (PGs) and progesterone receptor (PGR). Areg and Ereg mRNA and protein levels were reduced significantly in COCs and ovaries collected from prostaglandin synthase 2 (Ptgs2) null mice and Pgr null (PRKO) mice at 4 h and 8 h after human chorionic gonadotropin, respectively. In cultured COCs, FSH/forskolin induced Areg mRNA within 0.5 h that peaked at 4 h, a process blocked by inhibitors of p38MAPK (SB203580), MAPK kinase (MEK) 1 (PD98059), and PTGS2 (NS398) but not protein kinase A (PKA) (KT5720). Conversely, AREG but not FSH induced Ptsg2 mRNA at 0.5 h with peak expression of Ptgs2 and Areg mRNAs at 4 h, processes blocked by the EGF receptor tyrosine kinase inhibitor AG1478 (AG), PD98059, and NS398. PGE2 reversed the inhibitory effects of AG on AREG-induced expression of Areg but not Ptgs2, placing Ptgs2 downstream of EGF-R signaling. Phorbol 12-myristate 13-acetate (PMA) and adenovirally expressed PGRA synergistically induced Areg mRNA in granulosa cells. In COCs, AREG not only induced genes that impact matrix formation but also genes involved in steroidogenesis (StAR, Cyp11a1) and immune cell-like functions (Pdcd1, Runx1, Cd52). Collectively, FSH-mediated induction of Areg mRNA via p38MAPK precedes AREG induction of Ptgs2 mRNA via ERK1/2. PGs acting via PTGER2 in cumulus cells provide a secondary, autocrine pathway to regulate expression of Areg in COCs showing critical functional links between G protein-coupled receptor and growth factor receptor pathways in ovulating follicles.
Roles of Purinergic P2X Receptors as Pacemaking Channels and Modulators of Calcium-Mobilizing Pathway in Pituitary Gonadotrophs
Authors: Zemkova Hana , Balik Ales , Jiang Yonghua , Kretschmannova Karla , Stojilkovic Stanko S. 
Published: March 2006

AbstractAnterior pituitary cells release ATP and express several subtypes of purinergic P2 receptors, but their biophysical properties and roles in spontaneous and receptor-controlled electrical activity have not been characterized. Here we focused on extracellular ATP actions in gonadotrophs from embryonic, neonatal, and adult rats. In cells from all three age groups, the Ca2+-mobilizing agonist GnRH induced oscillatory, hyperpolarizing, nondesensitizing, and slow deactivating currents. In contrast, ATP induced nonoscillatory, depolarizing, slowly desensitizing, and rapidly deactivating current, indicating that these cells express cation-conducting P2X channels but not Ca2+-mobilizing P2Y receptors. The amplitudes of P2X current response and the rates of receptor desensitization were dependent on ATP concentration. The biophysical and pharmacological properties of P2X currents were consistent with the expression of P2X2 subtype of channels in these cells. ATP-induced rapid depolarization of gonadotrophs lead to initiation of firing in quiescent cells, an increase in the frequency of action potentials in spontaneously active cells, and a transient stimulation of LH release. ATP also influenced GnRH-induced current and membrane potential oscillations and LH release in an extracellular Ca2+-dependent manner. These inositol 1,4,5-triphosphate-dependent oscillations were facilitated, slowed, or stopped, depending of ATP concentration, the time of its application, and the level of Ca2+ content in intracellular stores. These results indicate that, in gonadotrophs, P2X receptors could operate as pacemaking channels and modulators of GnRH-controlled electrical activity and secretion.