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Sample records for flt3 ligand induce

  1. Regulation mechanisms of the FLT3-ligand after irradiation; Mecanismes de regulation du FLT3-ligand apres irradiation

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    Prat-Lepesant, M

    2005-06-15

    The hematopoietic compartment is one of the most severely damaged after chemotherapy, radiotherapy or accidental irradiations. Whatever its origin, the resulting damage to the bone marrow remains difficult to evaluate. Thus, it would be of great interest to get a biological indicator of residual hematopoiesis in order to adapt the treatment to each clinical situation. Recent results indicated that the plasma Flt3 ligand concentration was increased in patients suffering from either acquired or induced aplasia, suggesting that Flt3 ligand might be useful as a biological indicator of bone marrow status. We thus followed in a mouse model as well as in several clinical situations the variations in plasma Flt3 ligand concentration, after either homogeneous or heterogeneous irradiations. These variations were correlated to the number of hematopoietic progenitors and to other parameters such as duration and depth of pancytopenia. The results indicated that the concentration of Flt3 ligand in the blood reflects the bone marrow status, and that the follow-up of plasma Flt3 ligand concentration could give predictive information about the bone marrow function and the duration and severity of pancytopenia and thrombocytopenia. Nevertheless, the clinical use of Flt3 ligand as a biological indicator of bone marrow damage require the knowledge of the mechanisms regulating the variations in plasma Flt3 ligand concentration. We thus developed a study in the mouse model. The results indicated that the variations in plasma Flt3 ligand variations were not solely due to a balance between its production by lymphoid cells and its consumption by hematopoietic cells. Moreover, we showed that T lymphocytes are not the main regulator of plasma Flt3 ligand concentration as previously suggested, and that other cell types, possibly including bone marrow stromal cells, might be strongly implicated. These results also suggest that the Flt3 ligand is a main systemic regulator of hematopoiesis

  2. Plasma Flt3-ligand as a prognostic bio-indicator of radiation-induced bone marrow damage; Le Flt3-ligand plasmatique, un bio-indicateur pronostique de l'atteinte radio-induite a la moelle osseuse

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    Bertho, J.M.; Frick, J.; Demarquay, C.; Aigueperse, J. [CEA Fontenay-aux-Roses, 92 (France). Inst. de Protection et de Surete Nucleaire; Gorin, N.C.; Gourmelon, P.; Laporte, J.Ph. [Centre Hospitalier Universitaire Saint-Antoine, 75 - Paris (France)

    2001-09-01

    Following an accidental irradiation, the choice between different therapeutic strategies mainly depends upon the estimated radiation-induced bone marrow damage. It was shown recently that the serum concentration of Flt3-ligand (FL), a cytokine mainly acting on immature haemopoietic cells, is highly elevated in either acquired or induced bone marrow aplasia. This suggested to us that FL measurement could be used as a bio-indicator of radiation-induced bone marrow damage. In order to verify this hypothesis, studies were conducted in a non human primate model as well as in humans undergoing radio and/or chemotherapy. Results showed that the increase in FL concentration on day 5 after irradiation is predictive of the evolution of the haemopoietic syndrome. Similar results were obtained in humans. Overall these results suggested that FL measurement could be used as a reliable bio indicator of radiation-induced bone marrow damage in accidental irradiation situations. (author)

  3. Transcriptional control of Flt3 ligand targeted by fluorouracil-induced Egr-1 promoter in hematopoietic damage

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    Fu Yan

    2009-09-01

    Full Text Available Abstract Background Ionizing radiation (IR activate the early growth response-1 (Egr-1 promoter by production of radical oxygen intermediates (ROIs. Egr-EF, an expression vector pCIneo containing Egr-1 promoter cloned upstream of the cDNA for Flt3 ligand, was used to treat hematopoietic damage. 5-fluorouracil, a commonly used chemotherapeutic agent, cause tumor cell death by producing DNA damage and generating ROIs. We therefore hypothesized that clinically employed chemotherapeutic agents that increase ROIs could also be employed to activate Egr-EF in a chemoinducible gene therapy strategy. The goal of this study was to explore the effect of Flt3 Ligand gene transcription regulated by fluorouracil-induced Egr-1 promoter on hematopoietic recovery. Methods Human Flt3 Ligand (FL cDNA and enhanced green fluorescent protein (EGFP cDNA were linked together with IRES and inserted into the expression vector pCI-neo under control of the Egr-1 promoter (Egr-EF. The vector was transfected into the HFCL human bone marrow stromal cell line, and these cells were exposed to 5-FU, a chemotherapeutic drug. Expression of FL by HFCL/EF cells after 5-FU treatment was determined with ELISA, western blot and RT-PCR assays. In addition, the effect of FL from HFCL/EF cell culture supernatants on growth of CD34+ cells from cord blood was also studied. HFCL/EF cells were injected into CB-17 combined immunodeficient (SCID mice with B16 melanoma. 5-FU was given three days after injection of the HFCL/EF cells. In the recipient mice, white blood cell levels in peripheral blood and expression of EGFP and FL in human stromal cells were measured. Tumor volumes in tumor-bearing mice were also measured. Results 5-FU treatment increased EGFP levels and secreted FL levels in HFCL/EF cells. Supernatants from HFCL/EF cell cultures treated with 5-FU increased CD34+ cell growth significantly. HFCL/EF exhibited an increase in the number of white blood cells after chemotherapy

  4. Flt3/Flt3L Participates in the Process of Regulating Dendritic Cells and Regulatory T Cells in DSS-Induced Colitis

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    Jing-Wei Mao

    2014-01-01

    Full Text Available The immunoregulation between dendritic cells (DCs and regulatory T cells (T-regs plays an important role in the pathogenesis of ulcerative colitis (UC. Recent research showed that Fms-like tyrosine kinase 3 (Flt3 and Flt3 ligand (Flt3L were involved in the process of DCs regulating T-regs. The DSS-induced colitis model is widely used because of its simplicity and many similarities with human UC. In this study, we observe the disease activity index (DAI and histological scoring, detect the amounts of DCs and T-regs and expression of Flt3/Flt3L, and investigate Flt3/Flt3L participating in the process of DCs regulating T-regs in DSS-induced colitis. Our findings suggest that the reduction of Flt3 and Flt3L expression may possibly induce colonic immunoregulatory imbalance between CD103+MHCII+DCs and CD4+CD25+FoxP3+T-regs in DSS-induced colitis. Flt3/Flt3L participates in the process of regulating DCS and T-regs in the pathogenesis of UC, at least, in the acute stage of this disease.

  5. Abundance of Flt3 and its ligand in astrocytic tumors

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    Eßbach C

    2013-05-01

    Full Text Available C Eßbach,1 N Andrae,1 D Pachow,1 J-P Warnke,2 A Wilisch-Neumann,1 E Kirches,1 C Mawrin11Department of Neuropathology, Otto-von-Guericke University, Magdeburg, 2Department of Neurosurgery, Paracelsus Hospital, Zwickau, GermanyBackground: Molecular targeted therapies for astrocytic tumors are the subject of growing research interest, due to the limited response of these tumors, especially glioblastoma multiforme, to conventional chemotherapeutic regimens. Several of these approaches exploit the inhibition of receptor tyrosine kinases. To date, it has not been elucidated if fms-like tyrosine kinase-3 (Flt3 and its natural ligand (Flt3L are expressed in astrocytic tumors, although some of the clinically intended small-molecule receptor tyrosine kinase inhibitors affect Flt3, while others do not. More importantly, the recent proof of principle for successful stimulation of the immune system against gliomas in preclinical models via local Flt3L application requires elucidation of this receptor tyrosine kinase pathway in these tumors in more detail. This therapy is based on recruitment of Flt3-positive dendritic cells, but may be corroborated by activity of this signaling pathway in glioma cells.Methods: Receptor and ligand expression was analyzed by real-time polymerase chain reaction in 31 astrocytic tumors (six diffuse and 11 anaplastic astrocytomas, 14 glioblastomas derived from patients of both genders and in glioblastoma cell lines. The two most common activating mutations of the Flt3 gene, ie, internal tandem duplication and D835 point mutation, were assessed by specific polymerase chain reaction.Results: A relatively high abundance of Flt3L mRNA (4%–6% of the reference, β2 microglobulin could be demonstrated in all tumor samples. Flt3 expression could generally be demonstrated by 40 specific polymerase chain reaction cycles and gel electrophoresis in 87% of the tumors, including all grades, although the small quantities of the receptor did

  6. Flt3 Ligand Regulates the Development of Innate Lymphoid Cells in Fetal and Adult Mice.

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    Baerenwaldt, Anne; von Burg, Nicole; Kreuzaler, Matthias; Sitte, Selina; Horvath, Edit; Peter, Annick; Voehringer, David; Rolink, Antonius G; Finke, Daniela

    2016-03-15

    Flt3 ligand (Flt3L) promotes survival of lymphoid progenitors in the bone marrow and differentiation of dendritic cells (DCs), but its role in regulating innate lymphoid cells (ILCs) during fetal and adult life is not understood. By using Flt3L knockout and transgenic mice, we demonstrate that Flt3L controls ILC numbers by regulating the pool of α4β7(-) and α4β7(+) lymphoid tissue inducer cell progenitors in the fetal liver and common lymphoid progenitors in the bone marrow. Deletion of flt3l severely reduced the number of fetal liver progenitors and lymphoid tissue inducer cells in the neonatal intestine, resulting in impaired development of Peyer's patches. In the adult intestine, NK cells and group 2 and 3 ILCs were severely reduced. This effect occurred independently of DCs as ILC numbers were normal in mice in which DCs were constitutively deleted. Finally, we could show that administration of Flt3L increased the number of NKp46(-) group 3 ILCs in wild-type and even in Il7(-/-) mice, which generally have reduced numbers of ILCs. Taken together, Flt3L significantly contributes to ILC and Peyer's patches development by targeting lymphoid progenitor cells during fetal and adult life.

  7. Phosphatidylinositol 3-kinase is essential for kit ligand-mediated survival, whereas interleukin-3 and flt3 ligand induce expression of antiapoptotic Bcl-2 family genes

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    Karlsson, Richard; Engström, Maria; Jönsson, Maria;

    2003-01-01

    not sustain their expression. Moreover, use of inhibitors implied that IL-3 was mainly exerting its effect on Bcl-2 at the level of transcription. The addition of LY294002 did not affect the expression of Bcl-2 and Bcl-XL, and thus, we conclude that expression of antiapoptotic Bcl-2 family member genes......Cytokines such as interleukin 3 (IL-3), kit ligand (KL), and flt3 ligand (FL) promote survival of hematopoietic stem cells and myeloid progenitor cells. In many cell types, members of the Bcl-2 gene family are major regulators of survival, but the mediating mechanisms are not fully understood...... is not dependent on PI-3 kinase activity. Our results indicate that cytokines exert distinct survival effects and that FL and IL-3 are capable of sustaining progenitor survival by up-regulating the expression of Bcl-2 and related genes....

  8. RUNX1 cooperates with FLT3-ITD to induce leukemia.

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    Behrens, Kira; Maul, Katrin; Tekin, Nilgün; Kriebitzsch, Neele; Indenbirken, Daniela; Prassolov, Vladimir; Müller, Ursula; Serve, Hubert; Cammenga, Jörg; Stocking, Carol

    2017-03-06

    Acute myeloid leukemia (AML) is induced by the cooperative action of deregulated genes that perturb self-renewal, proliferation, and differentiation. Internal tandem duplications (ITDs) in the FLT3 receptor tyrosine kinase are common mutations in AML, confer poor prognosis, and stimulate myeloproliferation. AML patient samples with FLT3-ITD express high levels of RUNX1, a transcription factor with known tumor-suppressor function. In this study, to understand this paradox, we investigated the impact of RUNX1 and FLT3-ITD coexpression. FLT3-ITD directly impacts on RUNX1 activity, whereby up-regulated and phosphorylated RUNX1 cooperates with FLT3-ITD to induce AML. Inactivating RUNX1 in tumors releases the differentiation block and down-regulates genes controlling ribosome biogenesis. We identified Hhex as a direct target of RUNX1 and FLT3-ITD stimulation and confirmed high HHEX expression in FLT3-ITD AMLs. HHEX could replace RUNX1 in cooperating with FLT3-ITD to induce AML. These results establish and elucidate the unanticipated oncogenic function of RUNX1 in AML. We predict that blocking RUNX1 activity will greatly enhance current therapeutic approaches using FLT3 inhibitors. © 2017 Behrens et al.

  9. An autologous in situ tumor vaccination approach for hepatocellular carcinoma. 2. Tumor-specific immunity and cure after radio-inducible suicide gene therapy and systemic CD40-ligand and Flt3-ligand gene therapy in an orthotopic tumor model.

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    Kawashita, Yujo; Deb, Niloy J; Garg, Madhur K; Kabarriti, Rafi; Fan, Zuoheng; Alfieri, Alan A; Roy-Chowdhury, Jayanta; Guha, Chandan

    2014-08-01

    Diffuse hepatocellular carcinoma (HCC) is a lethal disease that radiation therapy (RT) currently has a limited role in treating because of the potential for developing fatal radiation-induced liver disease. However, recently diffuse HCC, "radio-inducible suicide gene therapy" has been shown to enhance local tumor control and residual microscopic disease within the liver for diffuse HCC, by using a combination of chemoactivation and molecular radiosensitization. We have demonstrated that the addition of recombinant adenovirus-expressing human Flt3 ligand (Adeno-Flt3L) after radio-inducible suicide gene therapy induced a Th1-biased, immune response and enhanced tumor control in an ectopic model of HCC. We hypothesized that sequential administration of recombinant adenovirus-expressing CD40L (Adeno-CD40L) could further potentiate the efficacy of our trimodal therapy with RT + HSV-TK + Adeno-Flt3L. We examined our hypothesis in an orthotopic model of diffuse HCC using BNL1ME A.7R.1 (BNL) cells in Balb/c mice. BNL murine hepatoma cells (5 × 10(4)) transfected with an expression vector of HSV-TK under the control of a radiation-inducible promoter were injected intraportally into BALB/cJ mice. Fourteen days after the HCC injection, mice were treated with a 25 Gy dose of radiation to the whole liver, followed by ganciclovir (GCV) treatment and systemic adenoviral cytokine gene therapy (Flt3L or CD40L or both). Untreated mice died in 27 ± 4 days. Radiation therapy alone had a marginal effect on survival (median = 35 ± 7 days) and the addition of HSV-TK/GCV gene therapy improved the median survival to 47 ± 6 days. However, the addition of Adeno-Flt3L to radiation therapy and HSV-TK/GCV therapy significantly (P = 0.0005) increased survival to a median of 63 ± 20 days with 44% (7/16) of the animals still alive 116 days after tumor implantation. The curative effect of Flt3L was completely abolished when using immunodeficient nude mice or mice depleted for CD4, CD8 and

  10. FLT3 Ligand as a Molecular Adjuvant for Naked RNA Vaccines.

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    Kreiter, Sebastian; Diken, Mustafa; Selmi, Abderraouf; Petschenka, Jutta; Türeci, Özlem; Sahin, Ugur

    2016-01-01

    Intranodal immunization with antigen-encoding naked mRNA has proven to be an efficacious and safe approach to induce antitumor immunity. Thanks to its unique characteristics, mRNA can act not only as a source for antigen but also as an adjuvant for activation of the immune system. The search for additional adjuvants that can be combined with mRNA to further improve the potency of the immunization revealed Fms-like tyrosine kinase 3 (FLT3ligand as a potent candidate. Systemic administration of the dendritic cell-activating FLT3 ligand prior to or along with mRNA immunization-enhanced priming and expansion of antigen-specific CD8(+) T cells in lymphoid organs, T-cell homing into melanoma tumors, and therapeutic activity of the intranodally administered mRNA. Both compounds demonstrate a successful combination in terms of boosting the immune response. This chapter describes methods for intranodal immunization with naked mRNA by co-administration of FLT3 ligand, which leads to strong synergistic effects.

  11. Barley as a green factory for the production of functional Flt3 ligand.

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    Erlendsson, Lýdur S; Muench, Marcus O; Hellman, Ulf; Hrafnkelsdóttir, Soffía M; Jonsson, Anders; Balmer, Yves; Mäntylä, Einar; Orvar, Björn L

    2010-02-01

    Biologically active recombinant human Flt3 ligand was expressed and isolated from transgenic barley seeds. Its expression is controlled by a tissue specific promoter that confines accumulation of the recombinant protein to the endosperm tissue of the seed. The recombinant Flt3 ligand variant expressed in the seeds contains an HQ-tag for affinity purification on immobilized metal ion affinity chromatography (IMAC) resin. The tagged protein was purified from seed extracts to near homogeneity using sequential chromatography on IMAC affinity resin and cation exchange resin. We also show that the recombinant Flt3 ligand protein undergoes posttranslational modifications: it is a glycoprotein containing alpha-1,3-fucose and alpha-1,2-xylose. The HQ-tagged Flt3 ligand variant exhibits comparable biological activity to commercial Flt3 ligand. This is the first report showing expression and accumulation of recombinant human growth factor in barley seeds with a yield of active protein similar to a bacterial expression system. The present results demonstrate that plant molecular farming is a viable approach for the bioproduction of human-derived growth factors.

  12. Serum FLT-3 ligand in a busulphan-induced model of chronic bone marrow hypoplasia in the female CD-1 mouse.

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    Molyneux, Gemma; Gibson, Frances M; Whayman, Matthew; Turton, John A

    2008-04-01

    The concentration of the cytokine fms-like tyrosine kinase-3 ligand (FL) is elevated in the plasma of patients treated with chemotherapy or radiotherapy for malignant conditions. In addition, plasma FL is increased in patients with bone marrow failure resulting from stem-cell defects (e.g. aplastic anaemia). Our goal in the present study was to measure the concentration of serum FL in mice treated with the chemotherapeutic agent busulphan (BU) to induce bone marrow depression and relate changes in FL to effects on haemopoiesis. Female CD-1 mice were treated with BU (9.0 mg/kg) or vehicle by intraperitoneal injection on 10 occasions over 21 days. Animals were autopsied on days 1, 23, 72, 119 and 177 postdosing. A full blood count was performed, and serum prepared for FL analysis. Femoral marrow cell suspensions were prepared to assess the total femoral nucleated cell count (FNCC) and the number of committed haemopoietic progenitor cells (CFU-C). On days 1 and 23 postdosing, significant decreases were evident in many peripheral blood parameters; the FNCC and CFU-C were also reduced in BU-treated mice, in conjunction with increases in serum FL levels. On days 72, 119 and 177 postdosing, several peripheral blood and bone marrow parameters remained reduced and the concentration of serum FL continued to be significantly increased. Linear regression analysis demonstrated significant correlations between the concentration of serum FL in BU-treated mice and peripheral blood and bone marrow parameters; this suggests the possible use of serum FL as a potential biomarker for drug-induced bone marrow injury.

  13. A type I IFN–Flt3 ligand axis augments plasmacytoid dendritic cell development from common lymphoid progenitors

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    Chen, Yi-Ling; Chen, Ting-Ting; Pai, Li-Mei; Wesoly, Joanna; Bluyssen, Hans A.R.

    2013-01-01

    During infections and inflammation, plasmacytoid dendritic cells (pDCs) are the most potent type I interferon (IFN-I)–producing cells. However, the developmental origin of pDCs and the signals dictating pDC generation remain incompletely understood. Here, we report a synergistic role for IFN-I and Flt3 ligand (FL) in pDC development from common lymphoid progenitors (CLPs). Both conventional DCs (cDCs) and pDCs were generated from CLPs in response to FL, whereas pDC generation required higher concentrations of FL and concurrent IFN-I signaling. An absence of IFN-I receptor, impairment of IFN-I signaling, or neutralization of IFN-I significantly impeded pDC development from CLPs. Furthermore, FL induced IFN-I expression in CLPs, which in turn induced Flt3 up-regulation that facilitated survival and proliferation of CLPs, as well as their differentiation into pDCs. Collectively, these results define a critical role for the FL/IFN-I/Flt3 axis in pDC differentiation from CLPs. PMID:24145513

  14. Reversible resistance induced by FLT3 inhibition: a novel resistance mechanism in mutant FLT3-expressing cells.

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    Ellen Weisberg

    Full Text Available Clinical responses achieved with FLT3 kinase inhibitors in acute myeloid leukemia (AML are typically transient and partial. Thus, there is a need for identification of molecular mechanisms of clinical resistance to these drugs. In response, we characterized MOLM13 AML cell lines made resistant to two structurally-independent FLT3 inhibitors.MOLM13 cells were made drug resistant via prolonged exposure to midostaurin and HG-7-85-01, respectively. Cell proliferation was determined by Trypan blue exclusion. Protein expression was assessed by immunoblotting, immunoprecipitation, and flow cytometry. Cycloheximide was used to determine protein half-life. RT-PCR was performed to determine FLT3 mRNA levels, and FISH analysis was performed to determine FLT3 gene expression.We found that MOLM13 cells readily developed cross-resistance when exposed to either midostaurin or HG-7-85-01. Resistance in both lines was associated with dramatically elevated levels of cell surface FLT3 and elevated levels of phosphor-MAPK, but not phospho-STAT5. The increase in FLT3-ITD expression was at least in part due to reduced turnover of the receptor, with prolonged half-life. Importantly, the drug-resistant phenotype could be rapidly reversed upon withdrawal of either inhibitor. Consistent with this phenotype, no significant evidence of FLT3 gene amplification, kinase domain mutations, or elevated levels of mRNA was observed, suggesting that protein turnover may be part of an auto-regulatory pathway initiated by FLT3 kinase activity. Interestingly, FLT3 inhibitor resistance also correlated with resistance to cytosine arabinoside. Over-expression of FLT3 protein in response to kinase inhibitors may be part of a novel mechanism that could contribute to clinical resistance.

  15. Immunotherapeutical role of Flt3 ligand amplification of pulmonary dendritic cells in murine multiple organ dysfunction syndrome in vivo

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    Hong-wei WANG

    2012-08-01

    Full Text Available Objective To explore the therapeutic effect of Flt3 ligand (Flt3L on multiple organ dysfunction syndrome (MODS model via amplification of lung dendritic cells. Methods Animal model of MODS was replicated by injecting zymosan into the peritoneal cavity of BALB/c mice, and then the mice were randomly divided into Flt3L treatment group, MODS group, Flt3L group and control group. Mortality rate was observed. After 12 days, lung mononuclear cells were isolated by density gradient centrifugation and analyzed with flow cytometry. Blood AST, ALT, creatinine, lipase, amylase and glucose were determined by automatic biochemical analyzer. Pathological changes in lung tissue were observed under light microscope. Results Mortality in Flt3L treatment group decreased dramatically compared with MODS group. The proportions of myeloid, plasmacytoid and I-Ad+ DCs in Flt3L group were remarkably increased compared with control group, and the proportion of the three DC subsets in MODS group was much lower than that in control group. Howerver, Flt3L treatment dramatically increased the proportion of them in MODS group. In MODS group, the level of ALT, AST, lipase, amylase and creatinine remarkably increased and blood glucose decreased compared with that of Flt3L and control groups; but in Flt3L treatment group, the level of ALT, AST, lipase, amylase and creatinine decreased and blood glucose increased dramatically, and lung injury mitigated obviously compared with MODS group. Conclusion Flt3L could attenuate lung tissue injury in MODS model, improve organ function, and lower the mortality of experimental animals, thus exerting its immunotherapeutic effects by in vivo amplification of lung dendritic cells.

  16. CSF Neurofilament Light Chain but not FLT3 Ligand Discriminates Parkinsonian Disorders

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    Herbert, Megan K.; Aerts, Marjolein B.; Beenes, Marijke; Norgren, Niklas; Esselink, Rianne A. J.; Bloem, Bastiaan R.; Kuiperij, H. Bea; Verbeek, Marcel M.

    2015-01-01

    The differentiation between multiple system atrophy (MSA) and Parkinson’s disease (PD) is difficult, particularly in early disease stages. Therefore, we aimed to evaluate the diagnostic value of neurofilament light chain (NFL), fms-like tyrosine kinase ligand (FLT3L), and total tau protein (t-tau) in cerebrospinal fluid (CSF) as biomarkers to discriminate MSA from PD. Using commercially available enzyme-linked immunosorbent assays, we measured CSF levels of NFL, FLT3L, and t-tau in a discovery cohort of 36 PD patients, 27 MSA patients, and 57 non-neurological controls and in a validation cohort of 32 PD patients, 25 MSA patients, 15 PSP patients, 5 CBS patients, and 56 non-neurological controls. Cut-offs obtained from individual assays and binary logistic regression models developed from combinations of biomarkers were assessed. CSF levels of NFL were substantially increased in MSA and discriminated between MSA and PD with a sensitivity of 74% and specificity of 92% (AUC = 0.85) in the discovery cohort and with 80% sensitivity and 97% specificity (AUC = 0.94) in the validation cohort. FLT3L levels in CSF were significantly lower in both PD and MSA compared to controls in the discovery cohort, but not in the validation cohort. t-tau levels were significantly higher in MSA than PD and controls. Addition of either FLT3L or t-tau to NFL did not improve discrimination of PD from MSA above NFL alone. Our findings show that increased levels of NFL in CSF offer clinically relevant, high accuracy discrimination between PD and MSA. PMID:25999911

  17. CSF neurofilament light chain but not FLT3 ligand discriminates Parkinsonian disorders

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    Megan Kristy Herbert

    2015-05-01

    Full Text Available The differentiation between multiple system atrophy (MSA and Parkinson’s disease (PD is difficult, particularly in early disease stages. Therefore, we aimed to evaluate the diagnostic value of neurofilament light chain (NFL, fms-like tyrosine kinase ligand (FLT3L and total tau protein (t-tau in cerebrospinal fluid (CSF as biomarkers to discriminate MSA from PD. Using commercially available enzyme-linked immunoassays (ELISAs, we measured CSF levels of NFL, FLT3L and t-tau in a discovery cohort of 36 PD patients, 27 MSA patients and 57 non-neurological controls and in a validation cohort of 32 PD patients, 25 MSA patients, 15 PSP patients, 5 CBS patients, and 56 non-neurological controls. Cut-offs obtained from individual assays and binary logistic regression models developed from combinations of biomarkers were assessed. CSF levels of NFL were substantially increased in MSA and discriminated between MSA and PD with a sensitivity of 74% and specificity of 92% (AUC = 0.85 in the discovery cohort and with 80% sensitivity and 97% specificity (AUC = 0.94 in the validation cohort. FLT3L levels in CSF were significantly lower in both PD and MSA compared to controls in the discovery cohort, but not in the validation cohort. T-tau levels were significantly higher in MSA than PD and controls. Addition of either FLT3L or t-tau to NFL did not improve discrimination of PD from MSA above NFL alone. Our findings show that increased levels of NFL in CSF offer clinically relevant, high accuracy discrimination between PD and MSA.

  18. Suppressor of Cytokine Signaling 6 (SOCS6) Negatively Regulates Flt3 Signal Transduction through Direct Binding to Phosphorylated Tyrosines 591 and 919 of Flt3

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    Kazi, Julhash U; Sun, Jianmin; Phung, Bengt;

    2012-01-01

    The receptor tyrosine kinase Flt3 is an important growth factor receptor in hematopoiesis, and gain-of-function mutations of the receptor contribute to the transformation of acute myeloid leukemia. SOCS6 (suppressor of cytokine signaling 6) is a member of the SOCS family of E3 ubiquitin ligases...... that can regulate receptor tyrosine kinase signal transduction. In this study, we analyzed the role of SOCS6 in Flt3 signal transduction. The results show that ligand stimulation of Flt3 can induce association of SOCS6 and Flt3 and tyrosine phosphorylation of SOCS6. Phosphopeptide fishing indicated...... that SOCS6 binds directly to phosphotyrosines 591 and 919 of Flt3. By using stably transfected Ba/F3 cells with Flt3 and/or SOCS6, we show that the presence of SOCS6 can enhance ubiquitination of Flt3, as well as internalization and degradation of the receptor. The presence of SOCS6 also induces weaker...

  19. FLT3-regulated antigens as targets for leukemia-reactive cytotoxic T lymphocytes.

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    Brackertz, B; Conrad, H; Daniel, J; Kast, B; Krönig, H; Busch, D H; Adamski, J; Peschel, C; Bernhard, H

    2011-03-01

    The FMS-like tyrosine kinase 3 (FLT3) is highly expressed in acute myeloid leukemia (AML). Internal tandem duplications (ITD) of the juxtamembrane domain lead to the constitutive activation of the FLT3 kinase inducing the activation of multiple genes, which may result in the expression of leukemia-associated antigens (LAAs). We analyzed the regulation of LAA in FLT3-wild-type (WT)- and FLT3-ITD(+) myeloid cells to identify potential targets for antigen-specific immunotherapy for AML patients. Antigens, such as PR-3, RHAMM, Survivin, WT-1 and PRAME, were upregulated by constitutively active FLT3-ITD as well as FLT3-WT activated by FLT3 ligand (FL). Cytotoxic T-cell (CTL) clones against PR-3, RHAMM, Survivin and an AML-directed CTL clone recognized AML cell lines and primary AML blasts expressing FLT3-ITD, as well as FLT3-WT(+) myeloid dendritic cells in the presence of FL. Downregulation of FLT3 led to the abolishment of CTL recognition. Comparing our findings concerning LAA upregulation by the FLT3 kinase with those already made for the Bcr-Abl kinase, we found analogies in the LAA expression pattern. Antigens upregulated by both FLT3 and Bcr-Abl may be promising targets for the development of immunotherapeutical approaches against myeloid leukemia of different origin.

  20. Oncogenic roles of PRL-3 in FLT3-ITD induced acute myeloid leukaemia.

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    Park, Jung Eun; Yuen, Hiu Fung; Zhou, Jian Biao; Al-Aidaroos, Abdul Qader O; Guo, Ke; Valk, Peter J; Zhang, Shu Dong; Chng, Wee Joo; Hong, Cheng William; Mills, Ken; Zeng, Qi

    2013-09-01

    FLT3-ITD mutations are prevalent mutations in acute myeloid leukaemia (AML). PRL-3, a metastasis-associated phosphatase, is a downstream target of FLT3-ITD. This study investigates the regulation and function of PRL-3 in leukaemia cell lines and AML patients associated with FLT3-ITD mutations. PRL-3 expression is upregulated by the FLT3-STAT5 signalling pathway in leukaemia cells, leading an activation of AP-1 transcription factors via ERK and JNK pathways. PRL-3-depleted AML cells showed a significant decrease in cell growth. Clinically, high PRL-3 mRNA expression was associated with FLT3-ITD mutations in four independent AML datasets with 1158 patients. Multivariable Cox-regression analysis on our Cohort 1 with 221 patients identified PRL-3 as a novel prognostic marker independent of other clinical parameters. Kaplan-Meier analysis showed high PRL-3 mRNA expression was significantly associated with poorer survival among 491 patients with normal karyotype. Targeting PRL-3 reversed the oncogenic effects in FLT3-ITD AML models in vitro and in vivo. Herein, we suggest that PRL-3 could serve as a prognostic marker to predict poorer survival and as a promising novel therapeutic target for AML patients.

  1. Targeting FLT3 in primary MLL-gene-rearranged infant acute lymphoblastic leukemia.

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    Stam, Ronald W; den Boer, Monique L; Schneider, Pauline; Nollau, Peter; Horstmann, Martin; Beverloo, H Berna; van der Voort, Ella; Valsecchi, Maria G; de Lorenzo, Paola; Sallan, Stephen E; Armstrong, Scott A; Pieters, Rob

    2005-10-01

    Acute lymphoblastic leukemia (ALL) in infants is characterized by rearrangements of the mixed lineage leukemia (MLL) gene, drug resistance, and a poor treatment outcome. Therefore, novel therapeutic strategies are needed to improve prognosis. Recently, we showed that FLT3 is highly expressed in MLL rearranged ALL (MLL). Here we demonstrate FLT3 expression in infants with MLL (n = 41) to be significantly higher compared to both infant (n = 8; P < .001) and noninfant patients with ALL (n = 23; P = .001) carrying germline MLL genes. Furthermore, leukemic cells from infants with MLL were significantly more sensitive to the Fms-like tyrosine kinase 3 (FLT3) inhibitor PKC412 (N-benzoyl staurosporine) than noninfant ALL cells, and at least as sensitive as internal tandem duplication-positive (ITD+) AML cells. Surprisingly, activation loop mutations only occurred in about 3% (1 of 36) of the cases and no FLT3/ITDs were observed. However, measuring FLT3 phosphorylation in infants with MLL expressing varying levels of wild-type FLT3 revealed that high-level FLT3 expression is associated with ligand-independent FLT3 activation. This suggests that infant MLL cells displaying activated FLT3 as a result of overexpression can be targeted by FLT3 inhibitors such as PKC412. However, at concentrations of PKC412 minimally required to fully inhibit FLT3 phosphorylation, the cytotoxic effects were only fractional. Thus, PKC412-induced apoptosis in infant MLL cells is unlikely to be a consequence of FLT3 inhibition alone but may involve inhibition of multiple other kinases by this drug.

  2. FMS-LIKE TYROSINE KINASE (FLT3 GENE ITD MUTATION IN ACUTE MYELOID LEUKEMIA

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    Rajko Kusec

    2004-12-01

    Full Text Available Background. FLT3 is a class III receptor tyrosine kinase expressed in normal stem cells and blasts of myeloid leukemia. Internal tandem duplication (ITD of the FLT3 gene affecting the exons 14 and 15 leads to ligand-independent FLT3 dimerization and constitutive activation. This stimulates proliferation and induces inhibition of apoptosis which contributes to leukemogenesis. We have screened a panel of acute myeloid leukemia (AML patients for the occurrence of FLT3/ITD mutation and correlated this mutation to patients’ survival and basic hematological parameters.Methods. RT-PCR for ITD in exons 14 and 15 of FLT3 gene was done on bone marrow samples of 67 AML patients at diagnosis.Results. There was a 16.4% incidence of FLT3/ITD mutation in the cohort of examined patients. By cytognetic subgroups there were 2/6 t(15;17 and 1 of 4 t(8;21 positive patients. The rest had normal and 2 had complex karyotype. Majority were of FAB M2 or M4 phenotype. For a subset of patients taken into comparative survival analysis there was a clear disadvantage for FLT3/ITD patients. No difference was found for basic hematological parameters between two groups.Conclusions. As it is evident today that FLT3/ITD is the single most common genetic abnormality in AML that also presents unfavorable clinical prognostic marker, it should be included in molecular diagnostic testing of acute myeloid leukemia.

  3. Mutations of the epigenetics-modifying gene (DNMT3a, TET2, IDH1/2) at diagnosis may induce FLT3-ITD at relapse in de novo acute myeloid leukemia.

    Science.gov (United States)

    Wakita, S; Yamaguchi, H; Omori, I; Terada, K; Ueda, T; Manabe, E; Kurosawa, S; Iida, S; Ibaraki, T; Sato, Y; Todoroki, T; Hirakawa, T; Ryotokuji, T; Arai, K; Kitano, T; Mitamura, Y; Kosaka, F; Dan, K; Inokuchi, K

    2013-04-01

    Gene mutations were found in acute myeloid leukemia (AML) and their importance has been noted. To clarify the importance and stability of mutations, we examined gene mutations in paired samples at diagnosis and relapse of 34 adult AML patients. Five acquired gene mutations were detected at relapse. Of the 45 gene mutations at diagnosis, 11 of them were lost at relapse. The acquired mutations at relapse were all class I mutations as Fms-like tyrosine kinase 3 (FLT3) and rat sarcoma viral oncogene homolog (RAS) mutations. The disappeared mutations at relapse were 3 of 11 internal tandem duplications of FLT3 (FLT3-ITD) (27.3%), 3 of 3 FLT3 tyrosine kinase domain (FLT3-TKD) (100%), 3 of 13 Nucleophosmin 1 (23.1%) and 2 of 5 CCAAT/enhancer-binding protein-α (40%) mutations. However, epigenetics-modifying gene (DNMT3a, TET2 and IDH1/2) mutations had no change between diagnosis and relapse samples, and may become minimal residual disease marker. The frequency of FLT3-ITD at relapse in patients with DNMT3a mutation at diagnosis is significantly higher than those in patients without them (P=0.001). Moreover, the high frequency of FLT3-ITD at relapse is also seen in AML cases that initially present with any epigenetics-modifying gene mutations (Pgene mutations may cause genetic instability and induce FLT3-ITD, leading to resistance to therapy and relapse.

  4. Radioprotective effects of the expression of FLT3 ligand regulated by Egr-1 regulated element on radiation injury of SCID mice

    Institute of Scientific and Technical Information of China (English)

    Du Nan; Pei Xuetao; Luo Chengji; Su Yongping; Cheng Tianmin

    2001-01-01

    Objective:In order to explore the radioprotective effects of the expression of hematopoietic growth factors regulated by radio-inducible promoter on radiation injury. Methods:The human FL (Flt3 ligand) cDNA and EGFP (enhanced green fluorescent protein) cDNA were linked together with IRES and then inserted into the eukaryotic expression vector pCI-Egr, which was constructed by substituting CMV promoter in pCIneo with the Egr-1 promoter (Egr-EF). The vector was transferred into human bone marrow stromal cell line HFCL by lipofectin. The transduced cell clones (HFCL/EF) had been selected by the addition of G418. The cells were exposed to γ-radiation by 60 Co source for 0.5-20Gy. The expressions of transduced cells were detected with FACS, Northern blot ELISA and CFU assay. The HFCL/EF and CD34+ cells from human umbilical cord blood were one after the other transplanted i.v. into sublethally irradiated severe combined immunodeficient (SCID) mice. The white blood cell amount in peripheral blood and human cell engrafted in recipent mice were detected by flow cytometry and CFU-GM etc. Results:The activity of EGFP in transduced cells increased by 3.1 fold as compared to non-transduced cells at 18h after exposure to 2.5Gy. The amounts of secreted FL in serum-free supernatants of Egr-EF increased by 605.46±107.21pg/ml, which were significantly higher than the control group (214.45±35.61pg/ml). The effects of FL in HFCL/EF cultural supernatants on expansion of CD34+ cells derived from cord blood in the presence of SCF, IL-6 and IL-3 were also studied. The results showed that at day 10 of culture the number of CD34+ cells increased by 173. 09±11.58×103/ml, which was significantly higher than that of non-radiation group(68. 04± 13. 73 × 103/ml). It showed that radiation can enhance the ability of the supernatants containing FL of HFCL/EF to expand early hematopoietic progenitor cells and protect hematopoietic cells from radiation-injury effects. The HFCL/EF and CD34

  5. Novel anticancer compound [trifluoromethyl-substituted pyrazole N-nucleoside] inhibits FLT3 activity to induce differentiation in acute myeloid leukemia cells.

    Science.gov (United States)

    Saleh, Ayman M; Taha, Mutasem O; Aziz, Mohammad A; Al-Qudah, Mahmoud A; AbuTayeh, Reem F; Rizvi, Syed A

    2016-06-01

    Anticancer properties of chemically synthesized compounds have continuously been optimized for better efficacy and selectivity. Derivatives of heterocyclic compounds are well known to have selective antiproliferative effect against many types of cancer. In this study, we investigated the ability of an indigenously synthesized anticancer molecule, G-11 [1-(2",3",4",6"-Tetra-O-acetyl-β-D-glucopyranosyl)-4-(3'-trifluoromethylphenylhydrazono)-3-trifluoromethyl-1,4-dihydropyrazol-5-one], to cause selective cytotoxicity and induce differentiation in the acute myeloid leukemia HL-60 cells. G-11 was able to exert cytotoxic effect on hematological (Jurkat, U937, K562, HL-60, CCRF-SB) and solid tumor (MCF-7, HepG2, HeLa, Caco-2) cell lines, with IC50 values significantly lower than noncancerous cells (HEK-293, BJ and Vero) and normal peripheral blood mononuclear cells. G-11 induced differentiation of HL-60 cells to granulocytes and monocytes/macrophages by inhibiting the activation of FLT3 (CD135 tyrosine kinase). ITD-FLT3 mutation found in many acute myeloid leukemia patients could also be targeted by G-11 as exhibited by its inhibitory effect on MOLM-13 and MV4-11 cell lines. Molecular docking studies suggest the involvement of Leu616, Asp698, Cys694 and Cys828 residues in binding of G-11 to FLT3. The ability of G-11 to cause selective cytotoxicity and induce differentiation in cancer cells could be clinically relevant for therapeutic gains.

  6. Src-Like adaptor protein (SLAP) binds to the receptor tyrosine kinase Flt3 and modulates receptor stability and downstream signaling.

    Science.gov (United States)

    Kazi, Julhash U; Rönnstrand, Lars

    2012-01-01

    Fms-like tyrosine kinase 3 (Flt3) is an important growth factor receptor in hematopoiesis. Gain-of-function mutations of the receptor contribute to the transformation of acute myeloid leukemia (AML). Src-like adaptor protein (SLAP) is an interaction partner of the E3 ubiquitin ligase Cbl that can regulate receptor tyrosine kinases-mediated signal transduction. In this study, we analyzed the role of SLAP in signal transduction downstream of the type III receptor tyrosine kinase Flt3. The results show that upon ligand stimulation SLAP stably associates with Flt3 through multiple phosphotyrosine residues in Flt3. SLAP constitutively interacts with oncogenic Flt3-ITD and co-localizes with Flt3 near the cell membrane. This association initiates Cbl-dependent receptor ubiquitination and degradation. Depletion of SLAP expression by shRNA in Flt3-transfected Ba/F3 cells resulted in a weaker activation of FL-induced PI3K-Akt and MAPK signaling. Meta-analysis of microarray data from patient samples suggests that SLAP mRNA is differentially expressed in different cancers and its expression was significantly increased in patients carrying the Flt3-ITD mutation. Thus, our data suggest a novel role of SLAP in different cancers and in modulation of receptor tyrosine kinase signaling apart from its conventional role in regulation of receptor stability.

  7. Src-Like adaptor protein (SLAP binds to the receptor tyrosine kinase Flt3 and modulates receptor stability and downstream signaling.

    Directory of Open Access Journals (Sweden)

    Julhash U Kazi

    Full Text Available Fms-like tyrosine kinase 3 (Flt3 is an important growth factor receptor in hematopoiesis. Gain-of-function mutations of the receptor contribute to the transformation of acute myeloid leukemia (AML. Src-like adaptor protein (SLAP is an interaction partner of the E3 ubiquitin ligase Cbl that can regulate receptor tyrosine kinases-mediated signal transduction. In this study, we analyzed the role of SLAP in signal transduction downstream of the type III receptor tyrosine kinase Flt3. The results show that upon ligand stimulation SLAP stably associates with Flt3 through multiple phosphotyrosine residues in Flt3. SLAP constitutively interacts with oncogenic Flt3-ITD and co-localizes with Flt3 near the cell membrane. This association initiates Cbl-dependent receptor ubiquitination and degradation. Depletion of SLAP expression by shRNA in Flt3-transfected Ba/F3 cells resulted in a weaker activation of FL-induced PI3K-Akt and MAPK signaling. Meta-analysis of microarray data from patient samples suggests that SLAP mRNA is differentially expressed in different cancers and its expression was significantly increased in patients carrying the Flt3-ITD mutation. Thus, our data suggest a novel role of SLAP in different cancers and in modulation of receptor tyrosine kinase signaling apart from its conventional role in regulation of receptor stability.

  8. Targeting oncoprotein stability overcomes drug resistance caused by FLT3 kinase domain mutations.

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    Chuanjiang Yu

    Full Text Available FLT3 is the most frequently mutated kinase in acute myeloid leukemia (AML. Internal tandem duplications (ITDs in the juxta-membrane region constitute the majority of activating FLT3 mutations. Several FLT3 kinase inhibitors were developed and tested in the clinic with significant success. However, recent studies have reported the development of secondary drug resistance in patients treated with FLT3 inhibitors. Since FLT3-ITD is an HSP90 client kinase, we here explored if targeting the stability of drug-resistant FLT3 mutant protein could be a potential therapeutic option. We observed that HSP90 inhibitor treatment resulted in the degradation of inhibitor-resistant FLT3-ITD mutants and selectively induced toxicity in cells expressing FLT3-ITD mutants. Thus, HSP90 inhibitors provide a potential therapeutic choice to overcome secondary drug resistance following TKI treatment in FLT3-ITD positive AML.

  9. Rapid Exercise-Induced Mobilization of Dendritic Cells Is Potentially Mediated by a Flt3L- and MMP-9-Dependent Process in Multiple Sclerosis

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    Nathalie Deckx

    2015-01-01

    Full Text Available In healthy individuals, one exercise bout induces a substantial increase in the number of circulating leukocytes, while their function is transiently suppressed. The effect of one exercise bout in multiple sclerosis (MS is less studied. Since recent evidence suggests a role of dendritic cells (DC in the pathogenesis of MS, we investigated the effect of one combined endurance/resistance exercise bout on the number and function of DC in MS patients and healthy controls. Our results show a rapid increase in the number of DC in response to physical exercise in both MS patients and controls. Further investigation revealed that in particular DC expressing the migratory molecules CCR5 and CD62L were increased upon acute physical activity. This may be mediated by Flt3L- and MMP-9-dependent mobilization of DC, as demonstrated by increased circulating levels of Flt3L and MMP-9 following one exercise bout. Circulating DC display reduced TLR responsiveness after acute exercise, as evidenced by a less pronounced upregulation of activation markers, HLA-DR and CD86, on plasmacytoid DC and conventional DC, respectively. Our results indicate mobilization of DC, which may be less prone to drive inflammatory processes, following exercise. This may present a negative feedback mechanism for exercise-induced tissue damage and inflammation.

  10. DNA repair contributes to the drug-resistant phenotype of primary acute myeloid leukaemia cells with FLT3 internal tandem duplications and is reversed by the FLT3 inhibitor PKC412.

    Science.gov (United States)

    Seedhouse, C H; Hunter, H M; Lloyd-Lewis, B; Massip, A-M; Pallis, M; Carter, G I; Grundy, M; Shang, S; Russell, N H

    2006-12-01

    The presence of internal tandem duplications (ITD) mutations in the FMS-like tyrosine kinase 3 (FLT3) receptor influences the risk of relapse in acute myeloid leukaemia (AML). We have investigated DNA repair in FLT3-ITD and wild-type (WT) cells. Using the comet assay, we have demonstrated that the FLT3 inhibitor PKC412 significantly inhibits repair of DNA damage in the MV4-11-FLT3-ITD cell line and FLT3-ITD patient samples but not in the HL-60-FLT3-WT cell line or FLT3-WT patient samples. Following the discovery that transcript levels of the DNA repair gene RAD51 are significantly correlated with FLT3 transcript levels in FLT3-ITD patients, we further investigated the role of RAD51 in FLT3-ITD-AML. The reduction in DNA repair in PKC412-treated FLT3-ITD cells was shown to be associated with downregulation of RAD51 mRNA and protein expression and correlates with the maintenance of phosphorylated H2AX levels, implying that PKC412 inhibits the homologous recombination double-strand break repair pathway in FLT3-ITD cells. Using FLT3-short interfering RNA (siRNA), we also demonstrated that genetic silencing of FLT3 results in RAD51 downregulation in FLT3-ITD cells but not in FLT3-WT cells. This work suggests that the use of FLT3 inhibitors such as PKC412 may reverse the drug-resistant phenotype of FLT3-ITD-AML cells by inhibiting repair of chemotherapy-induced genotoxic damage and thereby reduce the risk of disease relapse.

  11. The new and recurrent FLT3 juxtamembrane deletion mutation shows a dominant negative effect on the wild-type FLT3 receptor

    Science.gov (United States)

    Sandhöfer, Nadine; Bauer, Julia; Reiter, Katrin; Dufour, Annika; Rothenberg, Maja; Konstandin, Nikola P.; Zellmeier, Evelyn; Tizazu, Belay; Greif, Philipp A.; Metzeler, Klaus H.; Hiddemann, Wolfgang; Polzer, Harald; Spiekermann, Karsten

    2016-01-01

    In acute myeloid leukemia (AML), the Fms-like tyrosine kinase 3 (FLT3) is one of the most frequently mutated genes. Recently, a new and recurrent juxtamembrane deletion mutation (p.Q569Vfs*2) resulting in a truncated receptor was identified. The mutated receptor is expressed on the cell surface and still binds its ligand but loses the ability to activate ERK signaling. FLT3 p.Q569fs-expressing Ba/F3 cells show no proliferation after ligand stimulation. Furthermore, coexpressed with the FLT3 wild-type (WT) receptor, the truncated receptor suppresses stimulation and activation of the WT receptor. Thus, FLT3 p.Q569Vfs*2, to our knowledge, is the first FLT3 mutation with a dominant negative effect on the WT receptor. PMID:27346558

  12. The new and recurrent FLT3 juxtamembrane deletion mutation shows a dominant negative effect on the wild-type FLT3 receptor.

    Science.gov (United States)

    Sandhöfer, Nadine; Bauer, Julia; Reiter, Katrin; Dufour, Annika; Rothenberg, Maja; Konstandin, Nikola P; Zellmeier, Evelyn; Tizazu, Belay; Greif, Philipp A; Metzeler, Klaus H; Hiddemann, Wolfgang; Polzer, Harald; Spiekermann, Karsten

    2016-06-27

    In acute myeloid leukemia (AML), the Fms-like tyrosine kinase 3 (FLT3) is one of the most frequently mutated genes. Recently, a new and recurrent juxtamembrane deletion mutation (p.Q569Vfs*2) resulting in a truncated receptor was identified. The mutated receptor is expressed on the cell surface and still binds its ligand but loses the ability to activate ERK signaling. FLT3 p.Q569fs-expressing Ba/F3 cells show no proliferation after ligand stimulation. Furthermore, coexpressed with the FLT3 wild-type (WT) receptor, the truncated receptor suppresses stimulation and activation of the WT receptor. Thus, FLT3 p.Q569Vfs*2, to our knowledge, is the first FLT3 mutation with a dominant negative effect on the WT receptor.

  13. D-HPLC analysis of the entire FLT3 gene in MLL rearranged and hyperdiploid acute lymphoblastic leukemia.

    Science.gov (United States)

    Stam, Ronald W; den Boer, Monique L; Schneider, Pauline; Meier, Marrit; Beverloo, H Berna; Pieters, Rob

    2007-11-01

    MLL rearranged and hyperdiploid acute lymphoblastic leukemia (ALL) are characterized by high-level FLT3 expression and constitutive FLT3 activation. As known activating FLT3 mutations are often absent in these patients, we screened the entire FLT3 coding sequence in MLL rearranged and hyperdiploid ALL cases for yet unidentified additional genetic alterations using denaturing D-HPLC. Both in MLL rearranged and hyperdiploid ALL we found that a small minority of samples, 7% and 10% respectively, carried genetic alterations. Although some of these alterations may induce FLT3 activation, the majority of these patients carry wild-type FLT3 genes.

  14. MuLV-related endogenous retroviral elements and Flt3 participate in aberrant end-joining events that promote B-cell leukemogenesis.

    Science.gov (United States)

    Johnson, Radia M; Papp, Eniko; Grandal, Ildiko; Kowalski, Paul E; Nutter, Lauryl; Wong, Raymond C C; Joseph-George, Ann M; Danska, Jayne S; Guidos, Cynthia J

    2014-06-01

    During V(D)J recombination of immunoglobulin genes, p53 and nonhomologous end-joining (NHEJ) suppress aberrant rejoining of DNA double-strand breaks induced by recombinase-activating genes (Rags)-1/2, thus maintaining genomic stability and limiting malignant transformation during B-cell development. However, Rag deficiency does not prevent B-cell leukemogenesis in p53/NHEJ mutant mice, revealing that p53 and NHEJ also suppress Rag-independent mechanisms of B-cell leukemogenesis. Using several cytogenomic approaches, we identified a novel class of activating mutations in Fms-like tyrosine kinase 3 (Flt3), a receptor tyrosine kinase important for normal hematopoiesis in Rag/p53/NHEJ triple-mutant (TM) B-cell leukemias. These mutant Flt3 alleles were created by complex genomic rearrangements with Moloney leukemia virus (MuLV)-related endogenous retroviral (ERV) elements, generating ERV-Flt3 fusion genes encoding an N-terminally truncated mutant form of Flt3 (trFlt3) that was transcribed from ERV long terminal repeats. trFlt3 protein lacked most of the Flt3 extracellular domain and induced ligand-independent STAT5 phosphorylation and proliferation of hematopoietic progenitor cells. Furthermore, expression of trFlt3 in p53/NHEJ mutant hematopoietic progenitor cells promoted development of clinically aggressive B-cell leukemia. Thus, repetitive MuLV-related ERV sequences can participate in aberrant end-joining events that promote development of aggressive B-cell leukemia. © 2014 Johnson et al.; Published by Cold Spring Harbor Laboratory Press.

  15. A novel bicistronic high-capacity gutless adenovirus vector that drives constitutive expression of herpes simplex virus type 1 thymidine kinase and tet-inducible expression of Flt3L for glioma therapeutics.

    Science.gov (United States)

    Puntel, Mariana; Muhammad, A K M G; Candolfi, Marianela; Salem, Alireza; Yagiz, Kader; Farrokhi, Catherine; Kroeger, Kurt M; Xiong, Weidong; Curtin, James F; Liu, Chunyan; Bondale, Niyati S; Lerner, Jonathan; Pechnick, Robert N; Palmer, Donna; Ng, Philip; Lowenstein, Pedro R; Castro, Maria G

    2010-06-01

    Glioblastoma multiforme (GBM) is a deadly primary brain tumor. Conditional cytotoxic/immune-stimulatory gene therapy (Ad-TK and Ad-Flt3L) elicits tumor regression and immunological memory in rodent GBM models. Since the majority of patients enrolled in clinical trials would exhibit adenovirus immunity, which could curtail transgene expression and therapeutic efficacy, we used high-capacity adenovirus vectors (HC-Ads) as a gene delivery platform. Herein, we describe for the first time a novel bicistronic HC-Ad driving constitutive expression of herpes simplex virus type 1 thymidine kinase (HSV1-TK) and inducible Tet-mediated expression of Flt3L within a single-vector platform. We achieved anti-GBM therapeutic efficacy with no overt toxicities using this bicistronic HC-Ad even in the presence of systemic Ad immunity. The bicistronic HC-Ad-TK/TetOn-Flt3L was delivered into intracranial gliomas in rats. Survival, vector biodistribution, neuropathology, systemic toxicity, and neurobehavioral deficits were assessed for up to 1 year posttreatment. Therapeutic efficacy was also assessed in animals preimmunized against Ads. We demonstrate therapeutic efficacy, with vector genomes being restricted to the brain injection site and an absence of overt toxicities. Importantly, antiadenoviral immunity did not inhibit therapeutic efficacy. These data represent the first report of a bicistronic vector platform driving the expression of two therapeutic transgenes, i.e., constitutive HSV1-TK and inducible Flt3L genes. Further, our data demonstrate no promoter interference and optimum gene delivery and expression from within this single-vector platform. Analysis of the efficacy, safety, and toxicity of this bicistronic HC-Ad vector in an animal model of GBM strongly supports further preclinical testing and downstream process development of HC-Ad-TK/TetOn-Flt3L for a future phase I clinical trial for GBM.

  16. FLT3-regulated antigens as targets for leukemia-reactive cytotoxic T lymphocytes

    OpenAIRE

    Brackertz, B; Conrad, H.; Daniel, J.; Kast, B; Krönig, H; Busch, D.H.; Adamski, J.; C Peschel; Bernhard, H

    2011-01-01

    The FMS-like tyrosine kinase 3 (FLT3) is highly expressed in acute myeloid leukemia (AML). Internal tandem duplications (ITD) of the juxtamembrane domain lead to the constitutive activation of the FLT3 kinase inducing the activation of multiple genes, which may result in the expression of leukemia-associated antigens (LAAs). We analyzed the regulation of LAA in FLT3-wild-type (WT)- and FLT3-ITD+ myeloid cells to identify potential targets for antigen-specific immunotherapy for AML patients. A...

  17. DOCK2 interacts with FLT3 and modulates the survival of FLT3-expressing leukemia cells.

    Science.gov (United States)

    Wu, M; Hamaker, M; Li, L; Small, D; Duffield, A S

    2017-03-01

    The FMS-like tyrosine kinase-3 (FLT3) gene is the most commonly mutated gene in acute myeloid leukemia (AML), and patients carrying internal tandem duplication (ITD) mutations have a poor prognosis. Long-term inhibition of FLT3 activity in these patients has been elusive. To provide a more complete understanding of FLT3 biology, a mass spectroscopy-based screen was performed to search for FLT3-interacting proteins. The screen identified dedicator of cytokinesis 2 (DOCK2), which is a guanine nucleotide exchange factor for Rho GTPases, and its expression is limited to hematolymphoid cells. We show that DOCK2 is expressed in leukemia cell lines and primary AML samples, and DOCK2 co-immunoprecipitates with wild-type FLT3 and FLT3/ITD. Knockdown (KD) of DOCK2 by shRNA selectively reduced cell proliferation and colony formation in leukemia cell lines with increased FLT3 activity, and greatly sensitized these cells to cytarabine treatment, alone and in combination with FLT3 tyrosine kinase inhibitors. DOCK2 KD in an FLT3/ITD-positive leukemia cell line also significantly prolonged survival in a mouse xenograft model. These findings suggest that DOCK2 is a potential therapeutic target for novel AML treatments, as this protein regulates the survival of leukemia cells with elevated FLT3 activity and sensitizes FLT3/ITD leukemic cells to conventional antileukemic agents.

  18. Activating FLT3 mutants show distinct gain-of-function phenotypes in vitro and a characteristic signaling pathway profile associated with prognosis in acute myeloid leukemia.

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    Hanna Janke

    Full Text Available About 30% of patients with acute myeloid leukemia (AML harbour mutations of the receptor tyrosine kinase FLT3, mostly internal tandem duplications (ITD and point mutations of the second tyrosine kinase domain (TKD. It was the aim of this study to comprehensively analyze clinical and functional properties of various FLT3 mutants. In 672 normal karyotype AML patients FLT3-ITD, but not FLT3-TKD mutations were associated with a worse relapse free and overall survival in multivariate analysis. In paired diagnosis-relapse samples FLT3-ITD showed higher stability (70% compared to FLT3-TKD (30%. In vitro, FLT3-ITD induced a strong activating phenotype in Ba/F3 cells. In contrast, FLT3-TKD mutations and other point mutations--including two novel mutations--showed a weaker but clear gain-of-function phenotype with gradual increase in proliferation and protection from apoptosis. The pro-proliferative capacity of the investigated FLT3 mutants was associated with cell surface expression and tyrosine 591 phosphorylation of the FLT3 receptor. Western blot experiments revealed STAT5 activation only in FLT3-ITD positive cell lines, in contrast to FLT3-non-ITD mutants, which displayed an enhanced signal of AKT and MAPK activation. Gene expression analysis revealed distinct difference between FLT3-ITD and FLT3-TKD for STAT5 target gene expression as well as deregulation of SOCS2, ENPP2, PRUNE2 and ART3. FLT3-ITD and FLT3 point mutations show a gain-of-function phenotype with distinct signalling properties in vitro. Although poor prognosis in AML is only associated with FLT3-ITD, all activating FLT3 mutations can contribute to leukemogenesis and are thus potential targets for therapeutic interventions.

  19. Protective effect of Flt3L on organ structure during advanced multiorgan dysfunction syndrome in mice

    Science.gov (United States)

    TIAN, GUANG; LU, JIANGYANG; GUO, HUIQIN; LIU, QIAN; WANG, HONGWEI

    2015-01-01

    The present study aimed to examine whether fms-related tyrosine kinase 3 ligand (Flt3L) protects the organs of mice with multiorgan dysfunction syndrome (MODS). Male C57BL/6 mice were randomly assigned to normal control, MODS and Flt3L treatment groups. The mouse models of MODS were established using intraperitoneal zymosan injections, followed by normal saline injections. The treatment group received 5 μg/kg Flt3L for seven days, beginning on day five following zymosan injection. On day 12, the mortality rates of the Flt3L treatment and the MODS groups were 7 and 18%, respectively. Marked pathological changes were observed in the liver, lungs, kidneys and heart of the mice with MODS, including degeneration and focal necrosis of parenchyma cells. Mild pathological changes were observed in different organs of the Flt3L-treated mice. In the MODS group, the number of CD4+ T lymphocytes was significantly reduced, whereas the number of CD8+ T lymphocytes was significantly increased compared with that in the normal control group; thus, the CD4+/CD8+ ratio was reduced. In the Flt3L treatment group, the average number of CD4+ T lymphocytes was not significantly different to the average number of CD4+ T lymphocytes in the normal group. In conclusion, Flt3L administration improved the immune status and alleviated the organ damage in mice with late-phase MODS. PMID:25672780

  20. Original of Flt3 ligand in bone marrow and peripheral blood of aplastic anemia and its means%再生障碍性贫血骨髓及外周血高水平Flt3配体的来源及意义

    Institute of Scientific and Technical Information of China (English)

    傅晋翔; 张学光

    2002-01-01

    目的研究再生障碍性贫血(AA)患者骨髓及外周血高水平FL(Flt3配体)的来源和影响因素.方法采用常规ELISA法测定AA患者骨髓和外周血FL含量,应用单色和双色免疫荧光标记流式细胞仪分析FL的分泌细胞及其受体Flt3的表达,并观察AA患者淋巴细胞经PHA激发后环胞菌素(CyA)对FL分泌的影响.结果AA患者骨髓和外周血FL含量显著升高,为正常的25倍以上,外周血和骨髓浓度无区别;正常人CD3+细胞内贮存有大量FL,而AA患者CD3+细胞以膜型FL为主,胞内基本无FL存在;淋巴细胞经PHA活化后可分泌FL,CyA可抑制FL的分泌.结论AA患者骨髓和外周血FL水平显著升高,主要由CD3+细胞产生.

  1. PU.1 is essential for CD11c expression in CD8(+/CD8(- lymphoid and monocyte-derived dendritic cells during GM-CSF or FLT3L-induced differentiation.

    Directory of Open Access Journals (Sweden)

    Xue-Jun Zhu

    Full Text Available Dendritic cells (DCs regulate innate and acquired immunity through their roles as antigen-presenting cells. Specific subsets of mature DCs, including monocyte-derived and lymphoid-derived DCs, can be distinguished based on distinct immunophenotypes and functional properties. The leukocyte integrin, CD11c, is considered a specific marker for DCs and it is expressed by all DC subsets. We created a strain of mice in which DCs and their progenitors could be lineage traced based on activity of the CD11c proximal promoter. Surprisingly, we observed levels of CD11c promoter activity that were similar in DCs and in other mature leukocytes, including monocytes, granulocytes, and lymphocytes. We sought to identify DNA elements and transcription factors that regulate DC-associated expression of CD11c. The ets transcription factor, PU.1, is a key regulator of DC development, and expression of PU.1 varies in different DC subsets. GM-CSF increased monocyte-derived DCs in mice and from mouse bone marrow cultured in vitro, but it did not increase CD8(+ lymphoid-derived DCs or B220(+ plasmacytoid DCs. FLT3L increased both monocyte-derived DCs and lymphoid-derived DCs from mouse bone marrow cultured in vitro. GM-CSF increased the 5.3 Kb CD11c proximal promoter activity in monocyte-derived DCs and CD8(+ lymphoid-derived DCs, but not in B220(+ plasmacytoid DCs. In contrast, FLT3L increased the CD11c proximal promoter activity in both monocyte-derived DCs and B220(+ plasmacytoid DCs. We used shRNA gene knockdown and chromatin immunoprecipitation to demonstrate that PU.1 is required for the effects of GM-CSF or FLT3L on monocyte-derived DCs. We conclude that both GM-CSF and FLT3L act through PU.1 to activate the 5.3 Kb CD11c proximal promoter in DCs and to induce differentiation of monocyte-derived DCs. We also confirm that the CD11c proximal promoter is not sufficient to direct lineage specificity of CD11c expression, and that additional DNA elements are required

  2. FLT3-ITDs Instruct a Myeloid Differentiation and Transformation Bias in Lymphomyeloid Multipotent Progenitors

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    Adam J. Mead

    2013-06-01

    Full Text Available Whether signals mediated via growth factor receptors (GFRs might influence lineage fate in multipotent progenitors (MPPs is unclear. We explored this issue in a mouse knockin model of gain-of-function Flt3-ITD mutation because FLT3-ITDs are paradoxically restricted to acute myeloid leukemia even though Flt3 primarily promotes lymphoid development during normal hematopoiesis. When expressed in MPPs, Flt3-ITD collaborated with Runx1 mutation to induce high-penetrance aggressive leukemias that were exclusively of the myeloid phenotype. Flt3-ITDs preferentially expanded MPPs with reduced lymphoid and increased myeloid transcriptional priming while compromising early B and T lymphopoiesis. Flt3-ITD-induced myeloid lineage bias involved upregulation of the transcription factor Pu.1, which is a direct target gene of Stat3, an aberrantly activated target of Flt3-ITDs, further establishing how lineage bias can be inflicted on MPPs through aberrant GFR signaling. Collectively, these findings provide new insights into how oncogenic mutations might subvert the normal process of lineage commitment and dictate the phenotype of resulting malignancies.

  3. Inhibition of FLT3 expression by green tea catechins in FLT3 mutated-AML cells.

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    Bui Thi Kim Ly

    Full Text Available Acute myeloid leukemia (AML is a heterogeneous disease characterized by a block in differentiation and uncontrolled proliferation. FLT3 is a commonly mutated gene found in AML patients. In clinical trials, the presence of a FLT3-ITD mutation significantly correlates with an increased risk of relapse and dismal overall survival. Therefore, activated FLT3 is a promising molecular target for AML therapies. In this study, we have shown that green tea polyphenols including (--epigallocatechin-3-gallate (EGCG, (--epigallocatechin (EGC, and (--epicatechin-3-gallate (ECG suppress the proliferation of AML cells. Interestingly, EGCG, EGC and ECG showed the inhibition of FLT3 expression in cell lines harboring FLT3 mutations. In the THP-1 cells harboring FLT3 wild-type, EGCG showed the suppression of cell proliferation but did not suppress the expression of FLT3 even at the concentration that suppress 100% cell proliferation. Moreover, EGCG-, EGC-and ECG-treated cells showed the suppression of MAPK, AKT and STAT5 phosphorylation. Altogether, we suggest that green tea polyphenols could serve as reagents for treatment or prevention of leukemia harboring FLT3 mutations.

  4. Human Flt3L generates dendritic cells from canine peripheral blood precursors: implications for a dog glioma clinical trial.

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    Weidong Xiong

    Full Text Available BACKGROUND: Glioblastoma multiforme (GBM is the most common primary brain tumor in adults and carries a dismal prognosis. We have developed a conditional cytotoxic/immunotherapeutic approach using adenoviral vectors (Ads encoding the immunostimulatory cytokine, human soluble fms-like tyrosine kinase 3 ligand (hsFlt3L and the conditional cytotoxic molecule, i.e., Herpes Simplex Type 1- thymide kinase (TK. This therapy triggers an anti-tumor immune response that leads to tumor regression and anti-tumor immunological memory in intracranial rodent cancer models. We aim to test the efficacy of this immunotherapy in dogs bearing spontaneous GBM. In view of the controversy regarding the effect of human cytokines on dog immune cells, and considering that the efficacy of this treatment depends on hsFlt3L-stimulated dendritic cells (DCs, in the present work we tested the ability of Ad-encoded hsFlt3L to generate DCs from dog peripheral blood and compared its effects with canine IL-4 and GM-CSF. METHODOLOGY/PRINCIPAL FINDINGS: Our results demonstrate that hsFlT3L expressed form an Ad vector, generated DCs from peripheral blood cultures with very similar morphological and phenotypic characteristics to canine IL-4 and GM-CSF-cultured DCs. These include phagocytic activity and expression of CD11c, MHCII, CD80 and CD14. Maturation of DCs cultured under both conditions resulted in increased secretion of IL-6, TNF-alpha and IFN-gamma. Importantly, hsFlt3L-derived antigen presenting cells showed allostimulatory potential highlighting their ability to present antigen to T cells and elicit their proliferation. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that hsFlt3L induces the proliferation of canine DCs and support its use in upcoming clinical trials for canine GBM. Our data further support the translation of hsFlt3L to be used for dendritic cells' vaccination and gene therapeutic approaches from rodent models to canine patients and its future

  5. Computer-guided design, synthesis, and biological evaluation of quinoxalinebisarylureas as FLT3 inhibitors.

    Science.gov (United States)

    Göring, Stefan; Bensinger, Dennis; Naumann, Eva C; Schmidt, Boris

    2015-03-01

    Activating mutations of FMS-like tyrosine kinase 3 (FLT3) are present in ∼30 % of patients with acute myeloid leukemia (AML) and are associated with poor prognosis. Point mutations in the tyrosine kinase domain (TKD) are observed as primary mutations or are acquired as secondary mutations in FLT3 with internal tandem duplications (ITDs) after treatment with tyrosine kinase inhibitors (TKIs). Although dozens of potent inhibitors against FLT3 ITD have been reported, activating TKD point mutations, especially at residues F691 and D835, remain the leading cause for therapy resistance, highlighting the consistent need for new potent inhibitors. Herein we report the identification and characterization of novel quinoxaline-based FLT3 inhibitors. We used the pharmacophore features of diverse known inhibitors as a starting point for a new optimization algorithm for type II TKIs, starting from an in silico library pharmacophore search and induced-fit docking in the known FLT3 structure. This led to the design of a set of diverse quinoxalinebisarylureas, which were profiled in an FLT3 kinase activity assay. The most promising compounds were further evaluated in a zebrafish embryo phenotype assay.

  6. Elevated frequencies of leukemic myeloid and plasmacytoid dendritic cells in acute myeloid leukemia with the FLT3 internal tandem duplication

    OpenAIRE

    Rickmann, Mareike; Krauter, Juergen; Stamer, Kathrin; Heuser, Michael; Salguero, Gustavo; Mischak-Weissinger, Eva; Ganser, Arnold; Stripecke, Renata

    2011-01-01

    Abstract Some 30% of acute myeloid leukemia (AML) patients display an internal tandem duplication (ITD) mutation in the FMS-like tyrosine kinase 3 (FLT3) gene. FLT3-ITDs are known to drive hematopoietic stem cells towards FLT3 ligand independent growth, but the effects on dendritic cell (DC) differentiation during leukemogenesis are not clear. We compared the frequency of cells with immunophenotype of myeloid DC (mDC: Lin?, HLA-DR+, CD11c+, CD86+) and plasmacytoid DC (pDC: Lin?, HL...

  7. Survey of activated FLT3 signaling in leukemia.

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    Ting-lei Gu

    Full Text Available Activating mutations of FMS-like tyrosine kinase-3 (FLT3 are found in approximately 30% of patients with acute myeloid leukemia (AML. FLT3 is therefore an attractive drug target. However, the molecular mechanisms by which FLT3 mutations lead to cell transformation in AML remain unclear. To develop a better understanding of FLT3 signaling as well as its downstream effectors, we performed detailed phosphoproteomic analysis of FLT3 signaling in human leukemia cells. We identified over 1000 tyrosine phosphorylation sites from about 750 proteins in both AML (wild type and mutant FLT3 and B cell acute lymphoblastic leukemia (normal and amplification of FLT3 cell lines. Furthermore, using stable isotope labeling by amino acids in cell culture (SILAC, we were able to quantified over 400 phosphorylation sites (pTyr, pSer, and pThr that were responsive to FLT3 inhibition in FLT3 driven human leukemia cell lines. We also extended this phosphoproteomic analysis on bone marrow from primary AML patient samples, and identify over 200 tyrosine and 800 serine/threonine phosphorylation sites in vivo. This study showed that oncogenic FLT3 regulates proteins involving diverse cellular processes and affects multiple signaling pathways in human leukemia that we previously appreciated, such as Fc epsilon RI-mediated signaling, BCR, and CD40 signaling pathways. It provides a valuable resource for investigation of oncogenic FLT3 signaling in human leukemia.

  8. SOCS1 cooperates with FLT3-ITD in the development of myeloproliferative disease by promoting the escape from external cytokine control

    DEFF Research Database (Denmark)

    Reddy, P.N.G.; Serve, H.; Brandts, C.H.;

    2012-01-01

    tandem duplication (ITD), when localized to the biosynthetic compartment, aberrantly activates STAT5. Here, we show that one of the target genes induced by STAT5 is suppressor of cytokine signaling (SOCS)1 - a surprising finding for a known tumor suppressor. Although SOCS1 expression in murine bone...... marrow severely impaired cytokine-induced colony growth, it failed to inhibit FLT3-ITD-supported colony growth, indicating resistance of FLT3-ITD to SOCS1. In addition, SOCS1 coexpression did not affect FLT3-ITD-mediated signaling or proliferation. Importantly, SOCS1 coexpression inhibited interferon......-αand interferon-γ signaling and protected FLT3-ITD hematopoietic cells from interferon-mediated growth inhibitory effects. In a murine bone marrow transplantation model, the coexpression of SOCS1 and FLT3-ITD significantly shortened the latency of a myeloproliferative disease compared with FLT3-ITD alone (P

  9. FLT3 inhibitors: clinical potential in acute myeloid leukemia

    Science.gov (United States)

    Hospital, Marie-Anne; Green, Alexa S; Maciel, Thiago T; Moura, Ivan C; Leung, Anskar Y; Bouscary, Didier; Tamburini, Jerome

    2017-01-01

    Acute myeloid leukemia (AML) is an aggressive hematopoietic malignancy that is cured in as few as 15%–40% of cases. Tremendous improvements in AML prognostication arose from a comprehensive analysis of leukemia cell genomes. Among normal karyotype AML cases, mutations in the FLT3 gene are the ones most commonly detected as having a deleterious prognostic impact. FLT3 is a transmembrane tyrosine kinase receptor, and alterations of the FLT3 gene such as internal tandem duplications (FLT3-ITD) deregulate FLT3 downstream signaling pathways in favor of increased cell proliferation and survival. FLT3 tyrosine kinase inhibitors (TKI) emerged as a new therapeutic option in FLT3-ITD AML, and clinical trials are ongoing with a variety of TKI either alone, combined with chemotherapy, or even as maintenance after allogenic stem cell transplantation. However, a wide range of molecular resistance mechanisms are activated upon TKI therapy, thus limiting their clinical impact. Massive research efforts are now ongoing to develop more efficient FLT3 TKI and/or new therapies targeting these resistance mechanisms to improve the prognosis of FLT3-ITD AML patients in the future. PMID:28223820

  10. ABT-869, a multitargeted receptor tyrosine kinase inhibitor: inhibition of FLT3 phosphorylation and signaling in acute myeloid leukemia.

    Science.gov (United States)

    Shankar, Deepa B; Li, Junling; Tapang, Paul; Owen McCall, J; Pease, Lori J; Dai, Yujia; Wei, Ru-Qi; Albert, Daniel H; Bouska, Jennifer J; Osterling, Donald J; Guo, Jun; Marcotte, Patrick A; Johnson, Eric F; Soni, Niru; Hartandi, Kresna; Michaelides, Michael R; Davidsen, Steven K; Priceman, Saul J; Chang, Jenny C; Rhodes, Katrin; Shah, Neil; Moore, Theodore B; Sakamoto, Kathleen M; Glaser, Keith B

    2007-04-15

    In 15% to 30% of patients with acute myeloid leukemia (AML), aberrant proliferation is a consequence of a juxtamembrane mutation in the FLT3 gene (FMS-like tyrosine kinase 3-internal tandem duplication [FLT3-ITD]), causing constitutive kinase activity. ABT-869 (a multitargeted receptor tyrosine kinase inhibitor) inhibited the phosphorylation of FLT3, STAT5, and ERK, as well as Pim-1 expression in MV-4-11 and MOLM-13 cells (IC(50) approximately 1-10 nM) harboring the FLT3-ITD. ABT-869 inhibited the proliferation of these cells (IC(50) = 4 and 6 nM, respectively) through the induction of apoptosis (increased sub-G(0)/G(1) phase, caspase activation, and PARP cleavage), whereas cells harboring wild-type (wt)-FLT3 were less sensitive. In normal human blood spiked with AML cells, ABT-869 inhibited phosphorylation of FLT3 (IC(50) approximately 100 nM), STAT5, and ERK, and decreased Pim-1 expression. In methylcellulose-based colony-forming assays, ABT-869 had no significant effect up to 1000 nM on normal hematopoietic progenitor cells, whereas in AML patient samples harboring both FLT3-ITD and wt-FLT3, ABT-869 inhibited colony formation (IC(50) = 100 and 1000 nM, respectively). ABT-869 dose-dependently inhibited MV-4-11 and MOLM-13 flank tumor growth, prevented tumor formation, regressed established MV-4-11 xenografts, and increased survival by 20 weeks in an MV-4-11 engraftment model. In tumors, ABT-869 inhibited FLT3 phosphorylation, induced apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]) and decreased proliferation (Ki67). ABT-869 is under clinical development for AML.

  11. Induced Apoptosis Investigation in Wild-type and FLT3-ITD Acute Myeloid Leukemia Cells by Nanochannel Electroporation and Single-cell qRT-PCR.

    Science.gov (United States)

    Gao, Keliang; Huang, Xiaomeng; Chiang, Chi-Ling; Wang, Xinmei; Chang, Lingqian; Boukany, Pouyan; Marcucci, Guido; Lee, Robert; Lee, Ly James

    2016-05-01

    Nanochannel electroporation (NEP) was applied to deliver precise dosages of myeloid cell leukemia-1 (Mcl-1)-specific siRNA and molecular beacons to two types of acute myeloid leukemia (AML) cells, FMS-like tyrosine kinase-3 wild-type (WT) and internal tandem duplications (ITD) type at the single-cell level. NEP, together with single-cell quantitative reverse transcription PCR, led to an observation showing nearly 20-folds more Mcl-1 siRNA than MCL1 mRNA were required to induce cell death for both cell lines and patient blasts, i.e., ~8,800 siRNAs for ~500 ± 50 mRNAs in ITD cells and ~6,000 siRNAs for ~300 ± 50 mRNAs in WT cells. A time-lapse study revealed that >75% MCL1 mRNA was downregulated within 1 hour after delivery of a small amount of siRNA. However, additional siRNA was required to inhibit the newly transcribed mRNA for >12 hours until the cell lost its ability of self-protection recovery. A multidelivery strategy of low doses and short delivery interval, which require 77% less siRNA and has the potential of lower side effects and clinical cost, was as effective as a single high-dose siRNA delivery. Our method provides a viable analytical tool to investigate gene silencing at the single-cell level for oligonucleotide-based therapy.

  12. The biology and targeting of FLT3 in pediatric leukemia

    Directory of Open Access Journals (Sweden)

    Colleen eAnnesley

    2014-09-01

    Full Text Available Despite remarkable improvement in treatment outcomes in pediatric leukemia over the past several decades, the prognosis for high risk groups of acute myeloid leukemia (AML and acute lymphoblastic leukemia (ALL, as well as for relapsed leukemia, remains poor. Intensified chemotherapy regimens have somewhat improved success rates, but at the cost of drastically increased morbidity and long term adverse effects. With the success of imatinib in Philadelphia-chromosome positive leukemia and all-trans retinoic acid in acute promyelocytic leukemia, the quest to find additional molecularly targeted therapies has generated much excitement over the past 15 years. Another such possible target in pediatric acute leukemia is FMS-like tyrosine kinase 3 (FLT3. FLT3 aberrations are among the most frequently identified transforming events in AML, and have significant clinical implications in both high risk pediatric AML and in certain high risk groups of pediatric ALL. Therefore, the successful targeting of FLT3 has tremendous potential to improve outcomes in these subsets of patients. This article will give an overview of the molecular function and signaling of the FLT3 receptor, as well as its pathogenic role in leukemia. We review the discovery of targeting FLT3, discuss currently available FLT3 inhibitors in pediatric leukemia and results of clinical trials to date, and finally, consider the future promise and challenges of FLT3 inhibitor therapy.

  13. Selective FLT3 inhibition of FLT3-ITD+ acute myeloid leukaemia resulting in secondary D835Y mutation: a model for emerging clinical resistance patterns.

    Science.gov (United States)

    Moore, A S; Faisal, A; Gonzalez de Castro, D; Bavetsias, V; Sun, C; Atrash, B; Valenti, M; de Haven Brandon, A; Avery, S; Mair, D; Mirabella, F; Swansbury, J; Pearson, A D J; Workman, P; Blagg, J; Raynaud, F I; Eccles, S A; Linardopoulos, S

    2012-07-01

    Acquired resistance to selective FLT3 inhibitors is an emerging clinical problem in the treatment of FLT3-ITD(+) acute myeloid leukaemia (AML). The paucity of valid pre-clinical models has restricted investigations to determine the mechanism of acquired therapeutic resistance, thereby limiting the development of effective treatments. We generated selective FLT3 inhibitor-resistant cells by treating the FLT3-ITD(+) human AML cell line MOLM-13 in vitro with the FLT3-selective inhibitor MLN518, and validated the resistant phenotype in vivo and in vitro. The resistant cells, MOLM-13-RES, harboured a new D835Y tyrosine kinase domain (TKD) mutation on the FLT3-ITD(+) allele. Acquired TKD mutations, including D835Y, have recently been identified in FLT3-ITD(+) patients relapsing after treatment with the novel FLT3 inhibitor, AC220. Consistent with this clinical pattern of resistance, MOLM-13-RES cells displayed high relative resistance to AC220 and Sorafenib. Furthermore, treatment of MOLM-13-RES cells with AC220 lead to loss of the FLT3 wild-type allele and the duplication of the FLT3-ITD-D835Y allele. Our FLT3-Aurora kinase inhibitor, CCT137690, successfully inhibited growth of FLT3-ITD-D835Y cells in vitro and in vivo, suggesting that dual FLT3-Aurora inhibition may overcome selective FLT3 inhibitor resistance, in part due to inhibition of Aurora kinase, and may benefit patients with FLT3-mutated AML.

  14. Targeted Therapy of FLT3 in Treatment of AML—Current Status and Future Directions

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    Caroline Benedicte Nitter Engen

    2014-12-01

    Full Text Available Internal tandem duplications (ITDs of the gene encoding the Fms-Like Tyrosine kinase-3 (FLT3 receptor are present in approximately 25% of patients with acute myeloid leukemia (AML. The mutation is associated with poor prognosis, and the aberrant protein product has been hypothesized as an attractive therapeutic target. Various tyrosine kinase inhibitors (TKIs have been developed targeting FLT3, but in spite of initial optimism the first generation TKIs tested in clinical studies generally induce only partial and transient hematological responses. The limited treatment efficacy generally observed may be explained by numerous factors; extensively pretreated and high risk cohorts, suboptimal pharmacodynamic and pharmacokinetic properties of the compounds, acquired TKI resistance, or the possible fact that inhibition of mutated FLT3 alone is not sufficient to avoid disease progression. The second-generation agent quizartinb is showing promising outcomes and seems better tolerated and with less toxic effects than traditional chemotherapeutic agents. Therefore, new generations of TKIs might be feasible for use in combination therapy or in a salvage setting in selected patients. Here, we sum up experiences so far, and we discuss the future outlook of targeting dysregulated FLT3 signaling in the treatment of AML.

  15. Chronic FLT3-ITD Signaling in Acute Myeloid Leukemia Is Connected to a Specific Chromatin Signature

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    Pierre Cauchy

    2015-08-01

    Full Text Available Acute myeloid leukemia (AML is characterized by recurrent mutations that affect the epigenetic regulatory machinery and signaling molecules, leading to a block in hematopoietic differentiation. Constitutive signaling from mutated growth factor receptors is a major driver of leukemic growth, but how aberrant signaling affects the epigenome in AML is less understood. Furthermore, AML cells undergo extensive clonal evolution, and the mutations in signaling genes are often secondary events. To elucidate how chronic growth factor signaling alters the transcriptional network in AML, we performed a system-wide multi-omics study of primary cells from patients suffering from AML with internal tandem duplications in the FLT3 transmembrane domain (FLT3-ITD. This strategy revealed cooperation between the MAP kinase (MAPK inducible transcription factor AP-1 and RUNX1 as a major driver of a common, FLT3-ITD-specific gene expression and chromatin signature, demonstrating a major impact of MAPK signaling pathways in shaping the epigenome of FLT3-ITD AML.

  16. FLT3 internal tandem duplication and FLT3-D835 mutation in 80 AML patients categorized into cytogenetic risk groups

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    Ewa Mały DEF

    2010-10-01

    Full Text Available Background:Acute myeloid leukemia (AML is a clonal disorder characterized by various genetic abnormalities and variable response to treatment. About 50�0of patients with AML have no cytogenetic aberrations, presenting normal karyotype, and are categorized in the intermediate risk group. In this group detection of FLT3 mutations move a patient from the intermediate to the adverse risk group.Material/Methods:Bone marrow from 80 AML patients was cultured to obtain chromosome slides and then karyotype. Simultaneously DNA was isolated from bone marrow and PCR reaction was conducted to test the FLT3 mutation status (ITD and D835. For statistical analysis Chi squared test was used.Results:From the group of 80 AML patients seven were classified as a favorable risk group and FLT3/ITD was found only in one of these patients (14.28� and FLT3/D835 in another one (14.28� Fifteen patients showed a complex karyotype with more than three aberrations or with any aberration known as a poor prognosis. Among the adverse group FLT3/ITD was detected in three patients (20�20and D835 mutation in two other patients (13.33� Among 58 patients with normal karyotype in GTG banding FLT3/ITD occurred in six cases (10.34�20and D835 mutation in two cases (3.45� No significant difference was found among these three risk groups regarding presence or absence of FLT3/ITD and FLT/D835.Discussion:Molecular characterization of mutations in several genes, such as FLT3, NPM1, MLL, CEBPA, in acute myeloid leukemia, especially in normal karyotype cases, could be another factor after cytogenetic analysis to stratify AML patients into different prognostic categories.

  17. Generation and characterization of a highly effective protein substrate for analysis of FLT3 activity

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    Chen Yun

    2012-07-01

    Full Text Available Abstract Background Gain-of-function mutations of tyrosine kinase FLT3 are frequently found in acute myeloid leukemia (AML. This has made FLT3 an important marker for disease diagnosis and a highly attractive target for therapeutic drug development. This study is intended to generate a sensitive substrate for assays of the FLT3 enzymatic activity. Methods We expressed in Escherichia coli cells a glutathione S-transferase (GST fusion protein designated GST-FLT3S, which contains a peptide sequence derived from an autophosphorylation site of FLT3. The protein was used to analyze tyrosine kinase activity of baculovirus-expressed FLT3 and crude cell extracts of bone marrow cells from AML patients. It was also employed to perform FLT3 kinase assays for FLT3 inhibitor screening. Results GST-FLT3S in solution or on beads was strongly phosphorylated by recombinant proteins carrying the catalytic domain of wild type FLT3 and FLT3D835 mutants, with the latter exhibiting much higher activity and efficiency. GST-FLT3S was also able to detect elevated tyrosine kinase activity in bone marrow cell extracts from AML patients. A small-scale inhibitor screening led to identification of several potent inhibitors of wild type and mutant forms of FLT3. Conclusions GST-FLT3S is a sensitive protein substrate for FLT3 assays. It may find applications in diagnosis of diseases related to abnormal FLT3 activity and in inhibitor screening for drug development.

  18. Genetic vaccination with Flt3-L and GM-CSF as adjuvants:Enhancement of cellular and humoral immune responses that results in protective immunity in a murine model of hepatitis C virus infection

    Institute of Scientific and Technical Information of China (English)

    Jens Encke; Jomo Bernardin; Jasmin Geib; Gocha Barbakadze; Raymond Bujdoso; Wolfgang Stremmel

    2006-01-01

    AIM: To investigate whether transfection of plasmid DNA encoding these cytokines enhances both humoral and cellular immune responses to hepatitis C virus (HCV) in a murine model.METHODS: We established a tumor model of HCV infection using syngenic mouse myeloma cells stably transfected with NS5. Co-vaccination of DNA encoding granulocyte macrophage colony-stimulating factor (GMCSF) and Fit-3 ligand together with a plasmid encoding for the HCV NS5 protein was carried out. Mice were sacrificed 14 d after the last immunization event with collection of spleen cells and serum to determine humoral and cellular immune responses.RESULTS: Co-vaccination of DNA encoding GM-CSF and Flt-3 ligand together with a plasmid encoding for the HCV NS5 protein induced increased antibody responses and CD4+ T cell proliferation to this protein. Vaccination with DNA encoding GM-CSF and Flt-3L promoted protection against tumor formation and/or reduction in mice coimmunized with cytokine-encoding DNA constructs. This suggests this strategy is capable of generating cytotoxic T lymphocyte activity in vivo. Following inoculation with plasmid DNA encoding Flt-3L, no increase in spleen size or in dendritic cell (DC) and natural killer cell numbers was observed. This was in contrast to a dramatic increase of both cell types after administration of recombinant Flt3-L in vivo. This suggests that vaccination with plasmid DNA encoding cytokines that regulate DC generation and mobilization may not promote unwanted side effects, such as autoimmunity, splenic fibrosis or hematopoietic malignancies that may occur with administration of recombinant forms of these proteins.CONCLUSION: Our data support the view that plasmid DNA vaccination is a promising approach for HCV immunization, and may provide a general adjuvant vaccination strategy against malignancies and other pathogens.

  19. Discovery and Rational Design of Pteridin-7(8H)-one-Based Inhibitors Targeting FMS-like Tyrosine Kinase 3 (FLT3) and Its Mutants.

    Science.gov (United States)

    Sun, Deheng; Yang, Yu; Lyu, Jiankun; Zhou, Wei; Song, Wenlin; Zhao, Zhenjiang; Chen, Zhuo; Xu, Yufang; Li, Honglin

    2016-07-14

    FLT3 has been validated as a therapeutic target for the treatment of acute myeloid leukemia (AML). In this paper, we describe for the first time, pteridin-7(8H)-one as a scaffold for potent FLT3 inhibitors derived from structural optimizations on irreversible EGFR inhibitors. The representative inhibitor (31) demonstrates single-digit nanomolar inhibition against FLT3 and subnanomolar KD for drug-resistance FLT3 mutants. In profiling of the in vitro tumor cell lines, it shows good selectivity against AML cells harboring FLT3-ITD mutations over other leukemia and solid tumor cell lines. The mechanism of action study illustrates that pteridin-7(8H)-one derivatives suppress the phosphorylation of FLT3 and its downstream pathways, thereby inducing G0/G1 cell cycle arrest and apoptosis in AML cells. In in vivo studies, 31 significantly suppresses the tumor growth in MV4-11 xenograft model. Overall, we provide a structurally distinct chemical scaffold with which to develop FLT3 mutants-selective inhibitors for AML treatment.

  20. Rat bone marrow-derived dendritic cells generated with GM-CSF/IL-4 or FLT3L exhibit distinct phenotypical and functional characteristics.

    Science.gov (United States)

    N'diaye, Marie; Warnecke, Andreas; Flytzani, Sevasti; Abdelmagid, Nada; Ruhrmann, Sabrina; Olsson, Tomas; Jagodic, Maja; Harris, Robert A; Guerreiro-Cacais, Andre Ortlieb

    2016-03-01

    Dendritic cells are professional APCs that play a central role in the initiation of immune responses. The limited ex vivo availability of dendritic cells inspires the widespread use of bone marrow-derived dendritic cells as an alternative in research. However, the functional characteristics of bone marrow-derived dendritic cells are incompletely understood. Therefore, we compared functional and phenotypic characteristics of rat bone marrow-derived dendritic cells generated with GM-CSF/IL-4 or FLT3 ligand bone marrow-derived dendritic cells. A comparison of surface markers revealed that FLT3 ligand-bone marrow-derived dendritic cells expressed signal regulatory protein α, CD103, and CD4 and baseline levels of MHC class II, CD40, and CD86, which were highly up-regulated upon stimulation. Conversely, GM-CSF/IL-4-bone marrow-derived dendritic cells constitutively expressed signal regulatory protein α, CD11c, and CD11b but only mildly up-regulated MHC class II, CD40, or CD86 following stimulation. Expression of dendritic cell-associated core transcripts was restricted to FLT3 ligand-bone marrow-derived dendritic cells . GM-CSF/IL-4-bone marrow-derived dendritic cells were superior at phagocytosis but were outperformed by FLT3 ligand-bone marrow-derived dendritic cells at antigen presentation and T cell stimulation in vitro. Stimulated GM-CSF/IL-4-bone marrow-derived dendritic cells secreted more TNF, CCL5, CCL20, and NO, whereas FLT3 ligand-bone marrow-derived dendritic cells secreted more IL-6 and IL-12. Finally, whereas GM-CSF/IL-4-bone marrow-derived dendritic cell culture supernatants added to resting T cell cultures promoted forkhead box p3(+) regulatory T cell populations, FLT3 ligand-bone marrow-derived dendritic cell culture supernatants drove Th17 differentiation. We conclude that rat GM-CSF/IL-4-bone marrow-derived dendritic cells and FLT3 ligand-bone marrow-derived dendritic cells are functionally distinct. Our data support the current rationale that FLT3

  1. FLT3 and NPM-1 mutations in a cohort of acute promyelocytic leukemia patients from India

    Directory of Open Access Journals (Sweden)

    Suchitra Swaminathan

    2014-01-01

    Results: Frequency of FLT3/internal tandem duplication and FLT3/tyrosine kinase domain was found to be 25% and 7% respectively. We observed a high frequency of NPM1 mutation (45% in the present population of APL patients.

  2. The importance of relative mutant level for evaluating impact on outcome of KIT, FLT3 and CBL mutations in core-binding factor acute myeloid leukemia.

    Science.gov (United States)

    Allen, C; Hills, R K; Lamb, K; Evans, C; Tinsley, S; Sellar, R; O'Brien, M; Yin, J L; Burnett, A K; Linch, D C; Gale, R E

    2013-09-01

    Several different mutations collaborate with the fusion proteins in core-binding factor acute myeloid leukemia (CBF-AML) to induce leukemogenesis, but their prognostic significance remains unclear. We screened 354 predominantly younger (mutations and FLT3 internal tandem duplications (FLT3(ITD)) and assessed the impact of relative mutant level on outcome. Overall, 28% had KIT, 6% FLT3(ITD), 10% FLT3(TKD), 27% RAS and 6% CBL mutations. Mutant levels for all genes/loci were highly variable. KIT mutations were associated with a higher cumulative incidence of relapse but in multivariate analysis this was only significant for cases with a higher mutant level of 25% or greater (95% confidence interval (CI)=1.01-1.52, P=0.04). Similarly, only FLT3(ITD-HIGH) was a significant adverse factor for overall survival (OS; CI=1.27-5.39, P=0.004). Conversely, FLT3(TKD-HIGH) and CBL(HIGH) were both favorable factors for OS (CI= 0.31-0.89, P=0.01 and CI=0.05-0.85, P=0.02, respectively). KIT mutations were frequently lost at relapse, which is relevant to minimal residual disease detection and the clinical use of KIT inhibitors. These results indicate that relative mutant level should be taken into account when evaluating the impact of mutations in CBF-AML.

  3. Src-like adaptor protein 2 (SLAP2) binds to and inhibits FLT3 signaling

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    Moharram, Sausan A.; Chougule, Rohit A.; Su, Xianwei; Li, Tianfeng; Sun, Jianmin; Zhao, Hui; Rönnstrand, Lars; Kazi, Julhash U.

    2016-01-01

    Fms-like tyrosine kinase (FLT3) is a frequently mutated oncogene in acute myeloid leukemia (AML). FLT3 inhibitors display promising results in a clinical setting, but patients relapse after short-term treatment due to the development of resistant disease. Therefore, a better understanding of FLT3 downstream signal transduction pathways will help to identify an alternative target for the treatment of AML patients carrying oncogenic FLT3. Activation of FLT3 results in phosphorylation of FLT3 on several tyrosine residues that recruit SH2 domain-containing signaling proteins. We screened a panel of SH2 domain-containing proteins and identified SLAP2 as a potent interacting partner of FLT3. We demonstrated that interaction occurs when FLT3 is activated, and also, an intact SH2 domain of SLAP2 is required for binding. SLAP2 binding sites in FLT3 mainly overlap with those of SRC. SLAP2 over expression in murine proB cells or myeloid cells inhibited oncogenic FLT3-ITD-mediated cell proliferation and colony formation in vitro, and tumor formation in vivo. Microarray analysis suggests that higher SLAP2 expression correlates with a gene signature similar to that of loss of oncogene function. Furthermore, FLT3-ITD positive AML patients with higher SLAP2 expression displayed better prognosis compared to those with lower expression of SLAP2. Expression of SLAP2 blocked FLT3 downstream signaling cascades including AKT, ERK, p38 and STAT5. Finally, SLAP2 accelerated FLT3 degradation through enhanced ubiquitination. Collectively, our data suggest that SLAP2 acts as a negative regulator of FLT3 signaling and therefore, modulation of SLAP2 expression levels may provide an alternative therapeutic approach for FLT3-ITD positive AML. PMID:27458164

  4. Frequency and Prognostic Relevance of FLT3 Mutations in Saudi Acute Myeloid Leukemia Patients

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    Ghaleb Elyamany

    2014-01-01

    Full Text Available The Fms-like tyrosine kinase-3 (FLT3 is a receptor tyrosine kinase that plays a key role in cell survival, proliferation, and differentiation of hematopoietic stem cells. Mutations of FLT3 were first described in 1997 and account for the most frequent molecular mutations in acute myeloid leukemia (AML. AML patients with FLT3 internal tandem duplication (ITD mutations have poor cure rates the prognostic significance of point mutations; tyrosine kinase domain (TKD is still unclear. We analyzed the frequency of FLT3 mutations (ITD and D835 in patients with AML at diagnosis; no sufficient data currently exist regarding FLT3 mutations in Saudi AML patients. This study was aimed at evaluating the frequency of FLT3 mutations in patients with AML and its significance for prognosis. The frequency of FLT3 mutations in our study (18.56% was lower than many of the reported studies, FLT3-ITD mutations were observed in 14.4%, and FLT3-TKD in 4.1%, of 97 newly diagnosed AML patients (82 adult and 15 pediatric. Our data show significant increase of FLT3 mutations in male more than female (13 male, 5 female. Our results support the view that FLT3-ITD mutation has strong prognostic factor in AML patients and is associated with high rate of relapse, and high leucocytes and blast count at diagnosis and relapse.

  5. mTOR signaling is activated by FLT3 kinase and promotes survival of FLT3-mutated acute myeloid leukemia cells

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    Panayiotidis Panayiotis

    2010-11-01

    Full Text Available Abstract Activating mutations of the FLT3 gene mediate leukemogenesis, at least in part, through activation of PI3K/AKT. The mammalian target of rapamycin (mTOR-Raptor signaling pathway is known to act downstream of AKT. Here we show that the mTOR effectors, 4EBP1, p70S6K and rpS6, are highly activated in cultured and primary FLT3-mutated acute myeloid leukemia (AML cells. Introduction of FLT3-ITD expressing constitutively activated FLT3 kinase further activates mTOR and its downstream effectors in BaF3 cells. We also found that mTOR signaling contributes to tumor cell survival, as demonstrated by pharmacologic inhibition of PI3K/AKT/mTOR, or total silencing of the mTOR gene. Furthermore, inhibition of FLT3 kinase results in downregulation of mTOR signaling associated with decreased survival of FLT3-mutated AML cells. These findings suggest that mTOR signaling operates downstream of activated FLT3 kinase thus contributing to tumor cell survival, and may represent a promising therapeutic target for AML patients with mutated-FLT3.

  6. FLT3 and NPM1 mutations in Chinese patients with acute myeloid leukemia and normal cytogenetics.

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    Wang, Lei; Xu, Wei-lai; Meng, Hai-tao; Qian, Wen-bin; Mai, Wen-yuan; Tong, Hong-yan; Mao, Li-ping; Tong, Yin; Qian, Jie-jing; Lou, Yin-jun; Chen, Zhi-mei; Wang, Yun-gui; Jin, Jie

    2010-10-01

    Mutations of fms-like tyrosine kinase 3 (FLT3) and nucleophosmin (NPM1) exon 12 genes are the most common abnormalities in adult acute myeloid leukemia (AML) with normal cytogenetics. To assess the prognostic impact of the two gene mutations in Chinese AML patients, we used multiplex polymerase chain reaction (PCR) and capillary electrophoresis to screen 76 AML patients with normal cytogenetics for mutations in FLT3 internal tandem duplication (FLT3/ITD) and exon 12 of the NPM1 gene. FLT3/ITD mutation was detected in 15 (19.7%) of 76 subjects, and NPM1 mutation in 20 (26.3%) subjects. Seven (9.2%) cases were positive for both FLT3/ITD and NPM1 mutations. Significantly more FLT3/ITD aberration was detected in subjects with French-American-British (FAB) M1 (42.8%). NPM1 mutation was frequently detected in subjects with M5 (47.1%) and infrequently in subjects with M2 (11.1%). FLT3 and NPM1 mutations were significantly associated with a higher white blood cell count in peripheral blood and a lower CD34 antigen expression, but not age, sex, or platelet count. Statistical analysis revealed that the FLT3/ITD-positive group had a lower complete remission (CR) rate (53.3% vs. 83.6%). Survival analysis showed that the FLT3/ITD-positive/NPM1 mutation-negative group had worse overall survival (OS) and relapse-free survival (RFS). The FLT3/ITD-positive/NPM1 mutation-positive group showed a trend towards favorable survival compared with the FLT3/ITD-positive/NPM1 mutation-negative group (P=0.069). Our results indicate that the FLT3/ITD mutation might be a prognostic factor for an unfavorable outcome in Chinese AML subjects with normal cytogenetics, while NPM1 mutation may be a favorable prognostic factor for OS and RFS in the presence of FLT3/ITD.

  7. FLT3/ITD associated with an immature immunophenotype in PML-RARα leukemia

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    Mariko Takenokuchi

    2012-10-01

    Full Text Available Acute promyelocytic leukemia (APL is characterized by the specific PML-RARa fusion gene resulting from translocation t(15;17 (q22;q12. Internal tandem duplication (ITD of the FLT3 gene has been observed in approximately 35% of APLs, and large-scale studies have identified the presence of ITD as an adverse prognostic factor for acute myeloblastic leukemia (AML patients. Aberrant expressions of surface antigens, such as CD2, CD34, and CD56, have been found in APL, but the implications of this are not well understood. We investigated the incidence of the FLT3/ITD mutation and FLT3/D835 (I836 point mutation in 25 APL patients. Incidence ratios of FLT3/ITD, D835 (I836, and both FLT3/ITD and D835 (I836 were 36%, 36% and 8%, respectively. FLT3/ITD+ cases showed a predominance of the bcr3 isoform (P=0.008 and M3v morphology (P<0.001. We found that all FLT3/ITD+ cases expressed CD2 (9 of 9 more frequently than that of FLT3/ITD- (1 of 16 (P<0.001, while only one of the CD2+ cases (1 of 10, 10% did not harbor FLT3/ITD, and all CD2+CD34+ cases (5 of 5, 100% harbored FLT3/ITD. In addition, quantitative polymerase chain reaction analysis showed that FLT3 mRNA was more abundantly expressed in FLT3/ITD+ than that in FLT3/ITD- (P=0.025, while there was no difference between D835(I836+ and D835(I836- with regards to aberrant surface-antigen expression, expression levels of FLT3 mRNA, M3v morphology, and the bcr3 isoform of PML-RARa mRNA. This study demonstrates that the presence of FLT3/ITD, but not D835 (I836, is closely related to aberrant CD2 expression and high expression levels of FLT3 mRNA. Our findings also suggest that FLT3/ITD as a secondary genetic event may block differentiation at the immature stage of APL.

  8. Detection of FLT3 Oncogene Mutations in Acute Myeloid Leukemia Using Conformation Sensitive Gel Electrophoresis

    OpenAIRE

    2008-01-01

    FLT3 (fms-related tyrosine kinase 3) is a receptor tyrosine kinase class III that is expressed on by early hematopoietic progenitor cells and plays an important role in hematopoietic stem cell proliferation, differentiation and survival. FLT3 is also expressed on leukemia blasts in most cases of acute myeloid leukemia (AML). In order to determine the frequency of FLT3 oncogene mutations, we analyzed genomic DNA of adult de novo acute myeloid leukemia (AML). Polymerase chain reaction (PCR) and...

  9. PRL-3, a metastasis associated tyrosine phosphatase, is involved in FLT3-ITD signaling and implicated in anti-AML therapy.

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    Jianbiao Zhou

    Full Text Available Combination with other small molecule drugs represents a promising strategy to improve therapeutic efficacy of FLT3 inhibitors in the clinic. We demonstrated that combining ABT-869, a FLT3 inhibitor, with SAHA, a HDAC inhibitor, led to synergistic killing of the AML cells with FLT3 mutations and suppression of colony formation. We identified a core gene signature that is uniquely induced by the combination treatment in 2 different leukemia cell lines. Among these, we showed that downregulation of PTP4A3 (PRL-3 played a role in this synergism. PRL-3 is downstream of FLT3 signaling and ectopic expression of PRL-3 conferred therapeutic resistance through upregulation of STAT (signal transducers and activators of transcription pathway activity and anti-apoptotic Mcl-1 protein. PRL-3 interacts with HDAC4 and SAHA downregulates PRL-3 via a proteasome dependent pathway. In addition, PRL-3 protein was identified in 47% of AML cases, but was absent in myeloid cells in normal bone marrows. Our results suggest such combination therapies may significantly improve the therapeutic efficacy of FLT3 inhibitors. PRL-3 plays a potential pathological role in AML and it might be a useful therapeutic target in AML, and warrant clinical investigation.

  10. PRL-3, a metastasis associated tyrosine phosphatase, is involved in FLT3-ITD signaling and implicated in anti-AML therapy.

    Science.gov (United States)

    Zhou, Jianbiao; Bi, Chonglei; Chng, Wee-Joo; Cheong, Lip-Lee; Liu, Shaw-Cheng; Mahara, Sylvia; Tay, Kian-Ghee; Zeng, Qi; Li, Jie; Guo, Ke; Tan, Cheng Peow Bobby; Yu, Hanry; Albert, Daniel H; Chen, Chien-Shing

    2011-05-12

    Combination with other small molecule drugs represents a promising strategy to improve therapeutic efficacy of FLT3 inhibitors in the clinic. We demonstrated that combining ABT-869, a FLT3 inhibitor, with SAHA, a HDAC inhibitor, led to synergistic killing of the AML cells with FLT3 mutations and suppression of colony formation. We identified a core gene signature that is uniquely induced by the combination treatment in 2 different leukemia cell lines. Among these, we showed that downregulation of PTP4A3 (PRL-3) played a role in this synergism. PRL-3 is downstream of FLT3 signaling and ectopic expression of PRL-3 conferred therapeutic resistance through upregulation of STAT (signal transducers and activators of transcription) pathway activity and anti-apoptotic Mcl-1 protein. PRL-3 interacts with HDAC4 and SAHA downregulates PRL-3 via a proteasome dependent pathway. In addition, PRL-3 protein was identified in 47% of AML cases, but was absent in myeloid cells in normal bone marrows. Our results suggest such combination therapies may significantly improve the therapeutic efficacy of FLT3 inhibitors. PRL-3 plays a potential pathological role in AML and it might be a useful therapeutic target in AML, and warrant clinical investigation.

  11. Spontaneous Remission in an Older Patient with Relapsed FLT3 ITD Mutant AML

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    Pankit Vachhani

    2016-01-01

    Full Text Available Spontaneous remission (SR of acute myeloid leukemia (AML is a very rare phenomenon. AML characterized by FLT3 internal tandem duplication (FLT3 ITD is typically associated with an aggressive clinical course with rapid progression, relapse, and short overall survival in the absence of transplantation. We report here the first case of SR of FLT3 ITD mutant AML in the literature. Our patient was an elderly woman with relapsed NPM1 and FLT3 ITD mutant AML whose disease underwent SR for a brief duration without precipitating cause. We review the potential immune mechanisms underlying SR in AML and discuss the implications for novel immunotherapeutic approaches for FLT3 mutant AML.

  12. Neurotrophin-3 and FLT3 Tyrosine Kinase Receptor in Perinatal Life

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    Ariadne Malamitsi-Puchner

    2005-01-01

    Full Text Available Our aim is to determine—in 30 healthy full-term infants and their mothers—circulating levels of neurotrophin-3 (NT-3 (important for antenatal and postnatal brain development and implicated in the immune response and FLT3 tyrosine kinase receptor (FLT3 (controlling hematopoiesis and found in the nervous tissue, in the fetal and neonatal life. NT-3 levels, in contrast to FLT3 ones, increased significantly on the fourth postnatal day in relation to the low levels found in the mother, fetus, and day 1 neonate (P=.03, respectively. Maternal and umbilical NT3 levels positively correlated with respective FLT3 levels (P=.003 and P=.03. Circulating NT-3 levels increased in early neonatal life, possibly due to exposure to various stimuli soon after birth. FLT3 levels do not seem to behave accordingly, although these two substances probably synergize.

  13. Midostaurin and Decitabine in Treating Older Patients With Newly Diagnosed Acute Myeloid Leukemia and FLT3 Mutation

    Science.gov (United States)

    2016-10-10

    Acute Myeloid Leukemia With FLT3/ITD Mutation; Acute Myeloid Leukemia With Gene Mutations; FLT3 Tyrosine Kinase Domain Point Mutation; Secondary Acute Myeloid Leukemia; Untreated Adult Acute Myeloid Leukemia

  14. FLT3 Gene Mutation in Childhood Acute Leukemia: A Preliminary Study

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    Zefarina Zulkafli

    2014-01-01

    Full Text Available Introduction. FLT3 is a tyrosine kinase receptor involved in the proliferation and differentiation of hematopoietic stem cells. There are two types of common FLT3 gene mutation, internal tandem duplication and the D835 mutation, which are known to be associated with a poor clinical outcome in acute leukemia patients. Methods. This study evaluates the incidence of FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD in 38 pediatric patients diagnosed with acute lymphoblastic leukemia (ALL and acute myeloid leukemia (AML in Hospital Universiti Sains Malaysia. DNA extraction was done from archive bone marrow samples to determine FLT3-ITD mutations using polymerase chain reaction. Results. In this pediatric series, the age ranges were 2–14 years. However, no FLT3-ITD mutations were detected in any of the samples. Conclusion. This preliminary study suggested that the incidence of FLT3 gene mutation most probably was very low in pediatrics patients diagnosed with acute leukemia. A further study with larger number of patient samples is necessary to confirm the findings and to further appreciate the prognostic value of FLT3-ITD mutation among pediatrics patients.

  15. Potentiation of antileukemic therapies by the dual PI3K/PDK-1 inhibitor, BAG956: effects on BCR-ABL– and mutant FLT3-expressing cells

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    Weisberg, Ellen; Banerji, Lolita; Wright, Renee D.; Barrett, Rosemary; Ray, Arghya; Moreno, Daisy; Catley, Laurence; Jiang, Jingrui; Hall-Meyers, Elizabeth; Sauveur-Michel, Maira; Stone, Richard; Galinsky, Ilene; Fox, Edward; Kung, Andrew L.

    2008-01-01

    Mediators of PI3K/AKT signaling have been implicated in chronic myeloid leukemia (CML) and acute myeloid leukemia (AML). Studies have shown that inhibitors of PI3K/AKT signaling, such as wortmannin and LY294002, are able to inhibit CML and AML cell proliferation and synergize with targeted tyrosine kinase inhi-bitors. We investigated the ability of BAG956, a dual PI3K/PDK-1 inhibitor, to be used in combination with inhibitors of BCR-ABL and mutant FLT3, as well as with the mTOR inhibitor, rapamycin, and the rapamycin derivative, RAD001. BAG956 was shown to block AKT phosphorylation induced by BCR-ABL–, and induce apoptosis of BCR-ABL–expressing cell lines and patient bone marrow cells at concentrations that also inhibit PI3K signaling. Enhancement of the inhibitory effects of the tyrosine kinase inhibitors, imatinib and nilotinib, by BAG956 was demonstrated against BCR-ABL expressing cells both in vitro and in vivo. We have also shown that BAG956 is effective against mutant FLT3-expressing cell lines and AML patient bone marrow cells. Enhancement of the inhibitory effects of the tyrosine kinase inhibitor, PKC412, by BAG956 was demonstrated against mutant FLT3-expressing cells. Finally, BAG956 and rapamycin/RAD001 were shown to combine in a nonantagonistic fashion against BCR-ABL– and mutant FLT3-expressing cells both in vitro and in vivo. PMID:18184863

  16. IMC-EB10, an anti-FLT3 monoclonal antibody, prolongs survival and reduces nonobese diabetic/severe combined immunodeficient engraftment of some acute lymphoblastic leukemia cell lines and primary leukemic samples.

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    Piloto, Obdulio; Nguyen, Bao; Huso, David; Kim, Kyu-Tae; Li, Yiwen; Witte, Larry; Hicklin, Daniel J; Brown, Patrick; Small, Donald

    2006-05-01

    The class III receptor tyrosine kinase FLT3 is expressed on the blasts of >90% of patients with B-lineage acute lymphoblastic leukemias (ALL). In addition, it is expressed at extremely high levels in ALL patients with mixed lineage leukemia rearrangements or hyperdiploidy and is sometimes mutated in these same patients. In this report, we investigate the effects of treating ALL cell lines and primary samples with human anti-FLT3 monoclonal antibodies (mAb) capable of preventing binding of FLT3 ligand. In vitro studies, examining the ability of two anti-FLT3 mAbs (IMC-EB10 and IMC-NC7) to affect FLT3 activation and downstream signaling in ALL cell lines and primary blasts, yielded variable results. FLT3 phosphorylation was consistently inhibited by IMC-NC7 treatment, but in some cell lines, IMC-EB10 actually stimulated FLT3 activation, possibly as a result of antibody-mediated receptor dimerization. Through antibody-dependent, cell-mediated cytotoxicity, such an antibody could still prove efficacious against leukemia cells in vivo. In fact, IMC-EB10 treatment significantly prolonged survival and/or reduced engraftment of several ALL cell lines and primary ALL samples in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. This occurred even when IMC-EB10 treatment resulted in FLT3 activation in vitro. Moreover, fluorescence-activated cell sorting and PCR analysis of IMC-EB10-treated NOD/SCID mice surviving 150 days post-leukemic cell injection revealed that FLT3 immunotherapy reduced leukemic engraftment below the level of detection in these assays (IMC-EB10 treatment did not select for resistant cells, because cells surviving IMC-EB10 treatment remain sensitive to IMC-EB10 cytotoxicity upon retransplantation. In vivo studies involving either partial depletion or activation of natural killer (NK) cells show that most of the cytotoxic effect of IMC-EB10 is mediated through NK cells. Therefore, such an antibody, either naked or conjugated to radioactive

  17. Detection of FLT3 Oncogene Mutations in Acute Myeloid Leukemia Using Conformation Sensitive Gel Electrophoresis

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    Mamdooh Gari

    2008-11-01

    Full Text Available FLT3 (fms-related tyrosine kinase 3 is a receptor tyrosine kinase class III that is expressed on by early hematopoietic progenitor cells and plays an important role in hematopoietic stem cell proliferation, differentiation and survival. FLT3 is also expressed on leukemia blasts in most cases of acute myeloid leukemia (AML. In order to determine the frequency of FLT3 oncogene mutations, we analyzed genomic DNA of adult de novo acute myeloid leukemia (AML. Polymerase chain reaction (PCR and conformation-sensitive gel electrophoresis (CSGE were used for FLT3 exons 11, 14, and 15, followed by direct DNA sequencing. Two different types of functionally important FLT 3 mutations have been identified. Those mutations were unique to patients with inv(16, t(15:17 or t(8;21 and comprised fifteen cases with internal tandem duplication (ITD mutation in the juxtamembrane domain and eleven cases with point mutation (exon 20, Asp835Tyr. The high frequency of the flt3 proto-oncogene mutations in acute myeloid leukemia AML suggests a key role for the receptor function. The association of FLT3 mutations with chromosomal abnormalities invites speculation as to the link between these two changes in the pathogenesis of acute myeloid leukemiaAML. Furthermore, CSGE method has shown to be a rapid and sensitive screening method for detection of nucleotide alteration in FLT3 gene. Finally, this study reports, for the first time in Saudi Arabia, mutations in the human FLT3 gene in acute myeloid leukemia AML patients.

  18. Profiling of somatic mutations in acute myeloid leukemia with FLT3-ITD at diagnosis and relapse.

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    Garg, Manoj; Nagata, Yasunobu; Kanojia, Deepika; Mayakonda, Anand; Yoshida, Kenichi; Haridas Keloth, Sreya; Zang, Zhi Jiang; Okuno, Yusuke; Shiraishi, Yuichi; Chiba, Kenichi; Tanaka, Hiroko; Miyano, Satoru; Ding, Ling-Wen; Alpermann, Tamara; Sun, Qiao-Yang; Lin, De-Chen; Chien, Wenwen; Madan, Vikas; Liu, Li-Zhen; Tan, Kar-Tong; Sampath, Abhishek; Venkatesan, Subhashree; Inokuchi, Koiti; Wakita, Satoshi; Yamaguchi, Hiroki; Chng, Wee Joo; Kham, Shirley-Kow Yin; Yeoh, Allen Eng-Juh; Sanada, Masashi; Schiller, Joanna; Kreuzer, Karl-Anton; Kornblau, Steven M; Kantarjian, Hagop M; Haferlach, Torsten; Lill, Michael; Kuo, Ming-Chung; Shih, Lee-Yung; Blau, Igor-Wolfgang; Blau, Olga; Yang, Henry; Ogawa, Seishi; Koeffler, H Phillip

    2015-11-26

    Acute myeloid leukemia (AML) with an FLT3 internal tandem duplication (FLT3-ITD) mutation is an aggressive hematologic malignancy with a grave prognosis. To identify the mutational spectrum associated with relapse, whole-exome sequencing was performed on 13 matched diagnosis, relapse, and remission trios followed by targeted sequencing of 299 genes in 67 FLT3-ITD patients. The FLT3-ITD genome has an average of 13 mutations per sample, similar to other AML subtypes, which is a low mutation rate compared with that in solid tumors. Recurrent mutations occur in genes related to DNA methylation, chromatin, histone methylation, myeloid transcription factors, signaling, adhesion, cohesin complex, and the spliceosome. Their pattern of mutual exclusivity and cooperation among mutated genes suggests that these genes have a strong biological relationship. In addition, we identified mutations in previously unappreciated genes such as MLL3, NSD1, FAT1, FAT4, and IDH3B. Mutations in 9 genes were observed in the relapse-specific phase. DNMT3A mutations are the most stable mutations, and this DNMT3A-transformed clone can be present even in morphologic complete remissions. Of note, all AML matched trio samples shared at least 1 genomic alteration at diagnosis and relapse, suggesting common ancestral clones. Two types of clonal evolution occur at relapse: either the founder clone recurs or a subclone of the founder clone escapes from induction chemotherapy and expands at relapse by acquiring new mutations. Relapse-specific mutations displayed an increase in transversions. Functional assays demonstrated that both MLL3 and FAT1 exert tumor-suppressor activity in the FLT3-ITD subtype. An inhibitor of XPO1 synergized with standard AML induction chemotherapy to inhibit FLT3-ITD growth. This study clearly shows that FLT3-ITD AML requires additional driver genetic alterations in addition to FLT3-ITD alone.

  19. FLT3 INTERNAL TANDEM DUPLICATION AND D835 MUTATIONS IN PATIENTS WITH ACUTE LYMPHOBLASTIC LEUKEMIA AND ITS CLINICAL SIGNIFICANCE

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    Ghaleb Elyamany

    2014-05-01

    Full Text Available The fms-like tyrosine kinase 3 (FLT3 gene is a member of the class III receptor tyrosine kinase family, mutations of FLT3 were first described in 1997 and account for the most frequent molecular mutations in acute myeloid leukemia. No data currently exist regarding FLT3 mutations in Saudi acute lymphoblastic leukemia (ALL patients as no study has reported for FLT3 mutations in Saudi ALL patients. In this retrospective study, we have examined a cohort of 77 ALL patients, to determine the prevalence of FLT3 mutations and the possible prognostic relevance of these mutations in ALL patients and did correlations to other biologic factors, such as karyotype, molecular mutations, and leukocyte count. FLT3 internal tandem duplication (ITD mutations and point mutation in tyrosine kinase domain (D835 mutations were analyzed in ALL patients at diagnosis by polymerase chain reaction (PCR. 2 cases (2.6%, 2/77 were positive for FLT3 mutations, one was found to have FLT3/ITD and other was found to have FLT3/D835. Our findings suggest that FLT3 mutations were not common in Saudi ALL and did not affect clinical outcome.

  20. Flt3+ macrophage precursors commit sequentially to osteoclasts, dendritic cells and microglia

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    Hanau Daniel

    2002-10-01

    Full Text Available Abstract Background Macrophages, osteoclasts, dendritic cells, and microglia are highly specialized cells that belong to the mononuclear phagocyte system. Functional and phenotypic heterogeneity within the mononuclear phagocyte system may reveal differentiation plasticity of a common progenitor, but developmental pathways leading to such diversity are still unclear. Results Mouse bone marrow cells were expanded in vitro in the presence of Flt3-ligand (FL, yielding high numbers of non-adherent cells exhibiting immature monocyte characteristics. Cells expanded for 6 days, 8 days, or 11 days (day 6-FL, day 8-FL, and day 11-FL cells, respectively exhibited constitutive potential towards macrophage differentiation. In contrast, they showed time-dependent potential towards osteoclast, dendritic, and microglia differentiation that was detected in day 6-, day 8-, and day 11-FL cells, in response to M-CSF and receptor activator of NFκB ligand (RANKL, granulocyte-macrophage colony stimulating-factor (GM-CSF and tumor necrosis factor-α (TNFα, and glial cell-conditioned medium (GCCM, respectively. Analysis of cell proliferation using the vital dye CFSE revealed homogenous growth in FL-stimulated cultures of bone marrow cells, demonstrating that changes in differential potential did not result from sequential outgrowth of specific precursors. Conclusions We propose that macrophages, osteoclasts, dendritic cells, and microglia may arise from expansion of common progenitors undergoing sequential differentiation commitment. This study also emphasizes differentiation plasticity within the mononuclear phagocyte system. Furthermore, selective massive cell production, as shown here, would greatly facilitate investigation of the clinical potential of dendritic cells and microglia.

  1. Internal Tandem Duplication in FLT3 Attenuates Proliferation and Regulates Resistance to the FLT3 Inhibitor AC220 by Modulating p21Cdkn1a and Pbx1 in Hematopoietic Cells.

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    Mariko Abe

    Full Text Available Internal tandem duplication (ITD mutations in the Fms-related tyrosine kinase 3 (FLT3 gene (FLT3-ITD are associated with poor prognosis in patients with acute myeloid leukemia (AML. Due to the development of drug resistance, few FLT3-ITD inhibitors are effective against FLT3-ITD+ AML. In this study, we show that FLT3-ITD activates a novel pathway involving p21Cdkn1a (p21 and pre-B cell leukemia transcription factor 1 (Pbx1 that attenuates FLT3-ITD cell proliferation and is involved in the development of drug resistance. FLT3-ITD up-regulated p21 expression in both mouse bone marrow c-kit+-Sca-1+-Lin- (KSL cells and Ba/F3 cells. The loss of p21 expression enhanced growth factor-independent proliferation and sensitivity to cytarabine as a consequence of concomitantly enriching the S+G2/M phase population and significantly increasing the expression of Pbx1, but not Evi-1, in FLT3-ITD+ cells. This enhanced cell proliferation following the loss of p21 was partially abrogated when Pbx1 expression was silenced in FLT3-ITD+ primary bone marrow colony-forming cells and Ba/F3 cells. When FLT3-ITD was antagonized with AC220, a selective inhibitor of FLT3-ITD, p21 expression was decreased coincident with Pbx1 mRNA up-regulation and a rapid decline in the number of viable FLT3-ITD+ Ba/F3 cells; however, the cells eventually became refractory to AC220. Overexpressing p21 in FLT3-ITD+ Ba/F3 cells delayed the emergence of cells that were refractory to AC220, whereas p21 silencing accelerated their development. These data indicate that FLT3-ITD is capable of inhibiting FLT3-ITD+ cell proliferation through the p21/Pbx1 axis and that treatments that antagonize FLT3-ITD contribute to the subsequent development of cells that are refractory to a FLT3-ITD inhibitor by disrupting p21 expression.

  2. Quantitative trait mapping reveals a regulatory axis involving peroxisome proliferator-activated receptors, PRDM16, transforming growth factor-β2 and FLT3 in hematopoiesis.

    Science.gov (United States)

    Avagyan, Serine; Aguilo, Francesca; Kamezaki, Kenjiro; Snoeck, Hans-Willem

    2011-12-01

    Hematopoiesis is the process whereby BM HSCs renew to maintain their number or to differentiate into committed progenitors to generate all blood cells. One approach to gain mechanistic insight into this complex process is the investigation of quantitative genetic variation in hematopoietic function among inbred mouse strains. We previously showed that TGF-β2 is a genetically determined positive regulator of hematopoiesis. In the presence of unknown nonprotein serum factors TGF-β2, but not TGF-β1 or -β3, enhances progenitor proliferation in vitro, an effect that is subject to mouse strain-dependent variation mapping to a locus on chr.4, Tb2r1. TGF-β2-deficient mice show hematopoietic defects, demonstrating the physiologic role of this cytokine. Here, we show that TGF-β2 specifically and predominantly cell autonomously enhances signaling by FLT3 in vitro and in vivo. A coding polymorphism in Prdm16 (PR-domain-containing 16) underlies Tb2r1 and differentially regulates transcriptional activity of peroxisome proliferator-activated receptor-γ (PPARγ), identifying lipid PPAR ligands as the serum factors required for regulation of FLT3 signaling by TGF-β2. We furthermore show that PPARγ agonists play a FLT3-dependent role in stress responses of progenitor cells. These observations identify a novel regulatory axis that includes PPARs, Prdm16, and TGF-β2 in hematopoiesis.

  3. Deletion and deletion/insertion mutations in the juxtamembrane domain of the FLT3 gene in adult acute myeloid leukemia

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    Kristin K. Deeb

    2014-01-01

    Full Text Available In contrast to FLT3 ITD mutations, in-frame deletions in the FLT3 gene have rarely been described in adult acute leukemia. We report two cases of AML with uncommon in-frame mutations in the juxtamembrane domain of the FLT3 gene: a 3-bp (c.1770_1774delCTACGinsGT; p.F590_V592delinsLF deletion/insertion and a 12-bp (c.1780_1791delTTCAGAGAATAT; p.F594_Y597del deletion. We verified by sequencing that the reading frame of the FLT3 gene was preserved and by cDNA analysis that the mRNA of the mutant allele was expressed in both cases. Given the recent development of FLT3 inhibitors, our findings may be of therapeutic value for AML patients harboring similar FLT3 mutations.

  4. Downstream molecular pathways of FLT3 in the pathogenesis of acute myeloid leukemia: biology and therapeutic implications

    Directory of Open Access Journals (Sweden)

    Takahashi Shinichiro

    2011-04-01

    Full Text Available Abstract FLT3 is a type III receptor tyrosine kinase. Mutations of FLT3 comprise one of the most frequently identified types of genetic alterations in acute myeloid leukemia. One-third of acute myeloid leukemia patients have mutations of this gene, and the majority of these mutations involve an internal tandem duplication in the juxtamembrane region of FLT3, leading to constitutive activation of downstream signaling pathways and aberrant cell growth. This review summarizes the current understanding of the effects of the downstream molecular signaling pathways after FLT3 activation, with a particular focus on the effects on transcription factors. Moreover, this review describes novel FLT3-targeted therapies, as well as efficient combination therapies for FLT3-mutated leukemia cells.

  5. FLT3-ITD Mutations in Acute Myeloid Leukemia Patients in Northeast Thailand.

    Science.gov (United States)

    Kumsaen, Piyawan; Fucharoen, Goonnapa; Sirijerachai, Chittima; Chainansamit, Su-On; Wisanuyothin, Nittaya; Kuwatjanakul, Pichayanan; Wiangnon, Surapon

    2016-01-01

    The FLT3-ITD mutation is one of the most frequent genetic abnormalities in acute myeloid leukemia (AML) where it is associated with a poor prognosis. The FLT3-ITD mutation could, therefore, be a potential molecular prognostic marker important for risk-stratified treatment options. We amplified the FLT3 gene at exon 14 and 15 in 52 AML patients (aged between 2 months and 74 years) from 4 referral centers (a university hospital and 3 regional hospitals in Northeast Thailand), using a simple PCR method. FLT3-ITD mutations were found in 10 patients (19.2%), being more common in adults than in children (21.1% vs. 14.3%) and more prevalent in patients with acute promyelocytic leukemia (AML-M3) than AML-non M3 (4 of 10 AML-M3 vs. 6 of 42 AML- non M3 patients). Duplication sequences varied in size-between 27 and 171 nucleotides (median=63.5) and in their location. FLT3-ITD mutations with common duplication sequences accounted for a significant percentage in AML patients in northeastern Thailand. This simple PCR method is feasible for routine laboratory practice and these data could help tailor use of the national protocol for AML.

  6. Characteristics and Prognosis of Adult Acute Myeloid Leukemia with Internal Tandem Duplication in the FLT3 Gene

    OpenAIRE

    2013-01-01

    Objectives: Constitutive activation of the fms-like tyrosine kinase 3 (FLT3) receptor by internal tandem duplication (ITD) of the juxtamembrane region has been described in patients with acute myeloid leukemia. FLT3/ITDs are present in about 20-30% of all acute myeloid leukemia cases. It has been shown that the mutation is correlated with worse prognosis. However, none of the previous studies investigated which FAB subtype is associated with higher percentage of FLT3/ITD, thus the reason for ...

  7. Facile identification of dual FLT3-Aurora A inhibitors: a computer-guided drug design approach.

    Science.gov (United States)

    Chang Hsu, Yung; Ke, Yi-Yu; Shiao, Hui-Yi; Lee, Chieh-Chien; Lin, Wen-Hsing; Chen, Chun-Hwa; Yen, Kuei-Jung; Hsu, John T-A; Chang, Chungming; Hsieh, Hsing-Pang

    2014-05-01

    Computer-guided drug design is a powerful tool for drug discovery. Herein we disclose the use of this approach for the discovery of dual FMS-like receptor tyrosine kinase-3 (FLT3)-Aurora A inhibitors against cancer. An Aurora hit compound was selected as a starting point, from which 288 virtual molecules were screened. Subsequently, some of these were synthesized and evaluated for their capacity to inhibit FLT3 and Aurora kinase A. To further enhance FLT3 inhibition, structure-activity relationship studies of the lead compound were conducted through a simplification strategy and bioisosteric replacement, followed by the use of computer-guided drug design to prioritize molecules bearing a variety of different terminal groups in terms of favorable binding energy. Selected compounds were then synthesized, and their bioactivity was evaluated. Of these, one novel inhibitor was found to exhibit excellent inhibition of FLT3 and Aurora kinase A and exert a dramatic antiproliferative effect on MOLM-13 and MV4-11 cells, with an IC50 value of 7 nM. Accordingly, it is considered a highly promising candidate for further development.

  8. Characteristics and Prognosis of Adult Acute Myeloid Leukemia with Internal Tandem Duplication in the FLT3 Gene

    Directory of Open Access Journals (Sweden)

    Adhra Al-Mawali

    2013-11-01

    Full Text Available Objectives: Constitutive activation of the fms-like tyrosine kinase 3 (FLT3 receptor by internal tandem duplication (ITD of the juxtamembrane region has been described in patients with acute myeloid leukemia. FLT3/ITDs are present in about 20-30% of all acute myeloid leukemia cases. It has been shown that the mutation is correlated with worse prognosis. However, none of the previous studies investigated which FAB subtype is associated with higher percentage of FLT3/ITD, thus the reason for undertaking the current study.Methods: The prevalence and the potential prognostic impact of FLT3 mutations in 39 acute myeloid leukemia patients were analyzed by genomic polymerase chain reaction. Twelve samples with FLT3/ITDs and 27 acute myeloid leukemia samples without the mutations were compared with respect to clinical prognosis and FAB subtype. Results were correlated with cytogenetic data and the clinical response.Results: FLT3/ITD mutations were found in 31% of patients. FLT3/ITD was associated with similar clinical characteristics and was more prevalent in patients with normal karyotype (83%. Interestingly, half of the FLT3/ITD aberrations were found in patients with FAB M1 (50%, and fewer were found in patients with FAB M2 (8%, M4 (8%, and M5 (8%. Although less frequent in patients with cytogenetic aberrations, FLT3/ITDs were found in 17% of patients with t(15;17. Although the study was powered to 80%, patients with FLT3/ITD mutation did not show shorter complete remission duration or a higher relapse rate.Conclusion: The data confirm that FLT3/ITD mutations represent a common alteration in adult acute myeloid leukemia, mainly with normal karyotype (83% and de novo acute myeloid leukemia (75%, as compared to secondary acute myeloid leukemia (25% (p<0.001. It also showed that half of the M1-FAB subtype is FLT3/ITD positive. Therefore, FLT3/ITD is a therapeutic target, and thus inhibition of FLT3 tyrosine kinase activity may provide a new approach in

  9. Regulation of Stat5 by FAK and PAK1 in Oncogenic FLT3- and KIT-Driven Leukemogenesis

    Directory of Open Access Journals (Sweden)

    Anindya Chatterjee

    2014-11-01

    Full Text Available Oncogenic mutations of FLT3 and KIT receptors are associated with poor survival in patients with acute myeloid leukemia (AML and myeloproliferative neoplasms (MPNs, and currently available drugs are largely ineffective. Although Stat5 has been implicated in regulating several myeloid and lymphoid malignancies, how precisely Stat5 regulates leukemogenesis, including its nuclear translocation to induce gene transcription, is poorly understood. In leukemic cells, we show constitutive activation of focal adhesion kinase (FAK whose inhibition represses leukemogenesis. Downstream of FAK, activation of Rac1 is regulated by RacGEF Tiam1, whose inhibition prolongs the survival of leukemic mice. Inhibition of the Rac1 effector PAK1 prolongs the survival of leukemic mice in part by inhibiting the nuclear translocation of Stat5. These results reveal a leukemic pathway involving FAK/Tiam1/Rac1/PAK1 and demonstrate an essential role for these signaling molecules in regulating the nuclear translocation of Stat5 in leukemogenesis.

  10. Prognostic value of FLT3 mutations in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline monochemotherapy

    NARCIS (Netherlands)

    Barragan, Eva; Montesinos, Pau; Camos, Mireia; Gonzalez, Marcos; Calasanz, Maria J.; Roman-Gomez, Jose; Gomez-Casares, Maria T.; Ayala, Rosa; Lopez, Javier; Fuster, Oscar; Colomer, Dolors; Chillon, Carmen; Larrayoz, Maria J.; Sanchez-Godoy, Pedro; Gonzalez-Campos, Jose; Manso, Felix; Amador, Maria L.; Vellenga, Edo; Lowenberg, Bob; Sanz, Miguel A.

    2011-01-01

    Background Fms-like tyrosine kinase-3 (FLT3) gene mutations are frequent in acute promyelocytic leukemia but their prognostic value is not well established. Design and Methods We evaluated FLT3-internal tandem duplication and FLT3-D835 mutations in patients treated with all-trans retinoic acid and a

  11. Prognostic value of FLT3 mutations in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline monochemotherapy

    NARCIS (Netherlands)

    P. Montesinos (Pau); M. González (Marcos); F. Manso (Félix); E. Vellenga (Edo); B. Löwenberg (Bob); M.A. Sanz (Miguel Angel)

    2011-01-01

    textabstractBackground Fms-like tyrosine kinase-3 (FLT3) gene mutations are frequent in acute promyelocytic leukemia but their prognostic value is not well established. Design and Methods We evaluated FLT3-internal tandem duplication and FLT3-D835 mutations in patients treated with all-trans retinoi

  12. Prognostic value of FLT3 mutations in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline monochemotherapy

    NARCIS (Netherlands)

    Barragan, Eva; Montesinos, Pau; Camos, Mireia; Gonzalez, Marcos; Calasanz, Maria J.; Roman-Gomez, Jose; Gomez-Casares, Maria T.; Ayala, Rosa; Lopez, Javier; Fuster, Oscar; Colomer, Dolors; Chillon, Carmen; Larrayoz, Maria J.; Sanchez-Godoy, Pedro; Gonzalez-Campos, Jose; Manso, Felix; Amador, Maria L.; Vellenga, Edo; Lowenberg, Bob; Sanz, Miguel A.

    2011-01-01

    Background Fms-like tyrosine kinase-3 (FLT3) gene mutations are frequent in acute promyelocytic leukemia but their prognostic value is not well established. Design and Methods We evaluated FLT3-internal tandem duplication and FLT3-D835 mutations in patients treated with all-trans retinoic acid and

  13. Characterisation and Clinical Significance of FLT3-ITD and non-ITD in Acute Myeloid Leukaemia Patients in Kelantan, Northeast Peninsular Malaysia.

    Science.gov (United States)

    Yunus, Noraini Mat; Johan, Muhammad Farid; Ali Nagi Al-Jamal, Hamid; Husin, Azlan; Hussein, Abdul Rahim; Hassan, Rosline

    2015-01-01

    Mutations of the FMS-like tyrosine kinase-3 (FLT3) receptor gene may promote proliferation via activation of multiple signaling pathways. FLT3-internal tandem duplication (FLT3-ITD) is the most common gene alteration found in patients diagnosed with acute myeloid leukaemia (AML) and has been associated with poor prognosis. We performed mutational analysis of exons 14-15 and 20 of the FLT3 gene in 54 AML patients using PCR-CSGE (conformational sensitive gel electrophoresis) followed by sequencing analysis to characterise FLT3 mutations in adult patients diagnosed with AML at Hospital USM, Kelantan, Northeast Peninsular Malaysia. FLT3 exon 14-15 mutations were identified in 7 of 54 patients (13%) whereas no mutation was found in FLT3 exon 20. Six ITDs and one non-ITD mutation were found in exon 14 of the juxtamembrane (JM) domain of FLT3. FLT3-ITD mutations were associated with a significantly higher blast percentage (p-value=0.008) and white blood cell count (p-value=0.023) but there was no significant difference in median overall survival time for FLT3-ITD+/FLT3-ITD- within 2 years (p-value=0.374). The incidence of FLT3-ITD in AML patients in this particular region of Malaysia is low compared to the Western world and has a significant association with WBC and blast percentage.

  14. Single institute study of FLT3 mutation in acute myeloid leukemia with near tetraploidy in Serbia

    Indian Academy of Sciences (India)

    Vladimir Jurišić; Sonja Povlović; Nataša Čolović; Vesna Djordjevic; Vera Bunjevački; Gradimir Janković; Milica Čolović

    2009-08-01

    Patients with de novo acute myeloid leukemia (AML) and near-tetraploid or completely tetraploid karyotype at presentation are rare. We present four patients with near-tetraploidy/tetraploidy in a cohort of 426 consecutive AML patients (0.98%) in respect to their cytogenetic findings, immunophenotype pattern, response to chemotherapy, course of disease and molecular analyses including tyrosine kinase receptor FLT3 gene, NRAS gene, and tumour suppressor gene, p53. We have found FLT3/ITD mutation only in one patient among the four with near-tetraploidy. The main finding is that these patients had a variable clinical course, with two having a long period of remission (36 and 12 months) and two died, not having achieved remission.

  15. Temporal Changes in FLT3-ITD Regulation of Stem Cell Self-Renewal and Leukemogenesis

    Science.gov (United States)

    2015-09-01

    fetal, neonatal and adult progenitors. STAT5 was activated by FLT3-ITD at all stages of development, but MAPK was activated only in post-natal...effects on hematopoietic stem cells (HSCs) and other hematopoietic progenitors, we have been characterizing its function in fetal, neonatal and adult...both the American Society for Hematology annual meeting and the ISSCR annual meeting in the past year. I interact with my primary mentor on this

  16. Incidence and significance of FLT3-ITD and NPM1 mutations in patients with normal karyotype acute myeloid leukaemia.

    LENUS (Irish Health Repository)

    Haslam, K

    2012-02-01

    BACKGROUND: Acute myeloid leukaemia (AML) is a heterogeneous clonal disorder of haematopoietic progenitor cells. Approximately half of all adult AML patients have a normal karyotype (NK-AML) and an intermediate risk prognosis. AIMS: To determine the incidence and prognostic significance of NPM1 and FLT3-ITD mutations in a population of patients with NK-AML. METHODS: FLT3-ITD and NPM1 mutation status was retrospectively sought in presentation samples from 44 NK-AML patients. RESULTS: FLT3-ITD and NPM1 mutations were detected in 45.5 and 54.5% of patients, respectively, allowing stratification according to genotype. CONCLUSIONS: FLT3-ITD and NPM1 mutation status can be defined in NK-AML. Prospective screening for these mutations is advocated in all NK-AML patients, as the genotype is of clinical importance when considering treatment options including stem cell transplantation.

  17. Flt3L controls the development of radiosensitive dendritic cells in the meninges and choroid plexus of the steady-state mouse brain.

    Science.gov (United States)

    Anandasabapathy, Niroshana; Victora, Gabriel D; Meredith, Matthew; Feder, Rachel; Dong, Baojun; Kluger, Courtney; Yao, Kaihui; Dustin, Michael L; Nussenzweig, Michel C; Steinman, Ralph M; Liu, Kang

    2011-08-01

    Antigen-presenting cells in the disease-free brain have been identified primarily by expression of antigens such as CD11b, CD11c, and MHC II, which can be shared by dendritic cells (DCs), microglia, and monocytes. In this study, starting with the criterion of Flt3 (FMS-like receptor tyrosine kinase 3)-dependent development, we characterize the features of authentic DCs within the meninges and choroid plexus in healthy mouse brains. Analyses of morphology, gene expression, and antigen-presenting function established a close relationship between meningeal and choroid plexus DCs (m/chDCs) and spleen DCs. DCs in both sites shared an intrinsic requirement for Flt3 ligand. Microarrays revealed differences in expression of transcripts encoding surface molecules, transcription factors, pattern recognition receptors, and other genes in m/chDCs compared with monocytes and microglia. Migrating pre-DC progenitors from bone marrow gave rise to m/chDCs that had a 5-7-d half-life. In contrast to microglia, DCs actively present self-antigens and stimulate T cells. Therefore, the meninges and choroid plexus of a steady-state brain contain DCs that derive from local precursors and exhibit a differentiation and antigen-presenting program similar to spleen DCs and distinct from microglia.

  18. Mutation of NPM1 and FLT3 Genes in Acute Myeloid Leukemia and Their Association with Clinical and Immunophenotypic Features

    Directory of Open Access Journals (Sweden)

    Pradeep Singh Chauhan

    2013-01-01

    Full Text Available Background. Mutations in NPM1 and FLT3 genes represent the most frequent genetic alterations and important diagnostic and prognostic indicators in patients with acute myeloid leukemia (AML. Objective. We investigated the prevalence and clinical characteristics of NPM1 and FLT3 mutations in 161 patients of de novo AML including adults and children. Results. NPM1 mutation was found in 21% and FLT3 mutation in 25% of the AML patients. Thirteen (8% samples were positive for both NPM1 and FLT3/ITD mutations. Adult patients had significantly higher frequency of NPM1 mutation than children (25.8% versus 8.8%; P=0.02. Further, NPM1 mutation was found to be more frequent in patients above 45 years of age (P=0.02. NPM1 mutation was significantly associated with higher platelet count (P=0.05 and absence of hepatosplenomegaly (P=0.01, while FLT3/ITD mutation was associated with higher white blood count (P=0.01. Immunophenotypically, NPM1 mutation was associated with the lack of CD34 (P<0.001 and HLD-DR expression (P<0.001, while FLT3/ITD mutation was positively associated with the expression of CD7 (P=0.04. No correlation was found between NPM1 mutation and fusion gene. Interestingly, FLT3/ITD mutation was found to be inversely associated with AML/ETO fusion gene (P=0.04. Conclusions. The results suggest that distinct clinical and immunophenotypic characteristics of NPM1 and FLT3/ITD mutations present further insight into the molecular mechanism of leukemogenesis.

  19. 白血病患者Flt-3基因突变及其与白血病发生、预后的关系%Association of Fms-like tyrosine kinase-3 mutation with the occurrence and prognosis of leukemia in patients with leukemia

    Institute of Scientific and Technical Information of China (English)

    王彤; 王杰

    2007-01-01

    后判断的重要标志.%BACKGROUND: Fms-like tyrosine kinase-3 (FLT3) gene is one of the receptors for growth factors in early hematogenesis. By binding to its ligand (FL), FLT3 regulates the proliferation and differentiation of hematopoietic stem/pregenitor cells via cell signal transduction pathway. FLT3 juxtamembrane internal tandem duplication (ITD)mutation is correlated with leukemia onset, development and act as an independent factor for poor prognosis.OBJECTIVE: To explore the relationship between Flt-3/ITD mutation and acute leukemia (AL), and analyze its clinical implication.DESIGN: A repetitive measurement.SETTING: Department of Biochemistry and Molecular Biology, Shenyang Medical College.PARTICIPANTS: Totally 147 samples of leukemia patients were diagnosed by morphological bone marrow biopsy in Shenyang Central Hospitals affiliated to Shenyang Medical College from January 1999 to October 2004. They were 95 males and 52 females with the mean age of 14.5 years old (5-23 years old). According to FAB standard, there were 62 patients with acute leukemia [including 33 cases of acute myelocytic leukemia (AMLs, M1, M2), 3 cases of acute myelo-monocytic leukemia (AMMOLs, M4), 18 cases of acute monocytic leukemia (AMOLs, M5), 8 cases of acute megakaryocytic leukemia (AMKLs, M7)], 43 patients with acute lymphoblastic leukemia (ALLs), 13 patietns with juvenile chronic myelocytic leukemia (JCMLs) and 29 patients with myelodysplastic syndrome (MDSs). Informed contents were obtained from all the participants.METHOD: Flt-3/ITD was detected with polymerase chain reaction (PCR) sequence in the 147 leukemia patients.MArN OUTCOME MEASURES: The clinical manifestations and prognosis were observed in the ALL patients with Flt-3/ITD;The Flt-3 gene expression, Flt-3/ITD positive rate, duplication region and length were detected in all kinds of leukemia.to Flt-3 gene products, including 3 cases of AMLs (M1, M2), 1 case of AMMOL (M4), and 1 case of AMOL (M5). DNA sequencing and blast alignment revealed that ITDs

  20. Arsenic trioxide in front-line therapy of acute promyelocytic leukemia (C9710): prognostic significance of FLT3 mutations and complex karyotype.

    Science.gov (United States)

    Poiré, Xavier; Moser, Barry K; Gallagher, Robert E; Laumann, Kristina; Bloomfield, Clara D; Powell, Bayard L; Koval, Gregory; Gulati, Kabir; Holowka, Nicholas; Larson, Richard A; Tallman, Martin S; Appelbaum, Frederick R; Sher, Dorie; Willman, Cheryl; Paietta, Elisabeth; Stock, Wendy

    2014-07-01

    The addition of arsenic trioxide (ATO) to frontline therapy of acute promyelocytic leukemia (APL) has been shown to result in significant improvements in disease-free survival (DFS). FLT3 mutations are frequently observed in APL, but its prognostic significance remains unclear. We analyzed 245 newly diagnosed adult patients with APL treated on intergroup trial C9710 and evaluated previously defined biological and prognostic factors and their relationship to FLT3 mutations and to additional karyotypic abnormalities. FLT3 mutations were found in 48% of patients, including 31% with an internal tandem duplication (FLT3-ITD), 14% with a point mutation (FLT3-D835) and 2% with both mutations. The FLT3-ITD mutant level was uniformly low, < 0.5. Neither FLT3 mutation had an impact on remission rate, induction death rate, DFS or overall survival (OS). The addition of ATO consolidation improved outcomes regardless of FLT3 mutation type or level, initial white blood cell count, PML-RARA isoform type or transcript level. The presence of a complex karyotype was strongly associated with an inferior OS independently of post-remission treatment. In conclusion, the addition of ATO to frontline therapy overcomes the impact of previously described adverse prognostic factors including FLT3 mutations. However, complex karyotype is strongly associated with an inferior OS despite ATO therapy.

  1. Clonal evolution of AML on novel FMS-like tyrosine kinase-3 (FLT3 inhibitor therapy with evolving actionable targets

    Directory of Open Access Journals (Sweden)

    Pashtoon M. Kasi

    2016-01-01

    Full Text Available For acute myeloid leukemia (AML, identification of activating mutations in the FMS-like tyrosine kinase-3 (FLT3 has led to the development of several FLT3-inhibitors. Here we present clinical and next generation sequencing data at the time of progression of a patient on a novel FLT3-inhibitor clinical trial (ASP2215 to show that employing therapeutic interventions with these novel targeted therapies can lead to consequences secondary to selective pressure and clonal evolution of cancer. We describe novel findings alongside data on treatment directed towards actionable aberrations acquired during the process. (Clinical Trial: NCT02014558; registered at: 〈https://clinicaltrials.gov/ct2/show/NCT02014558〉

  2. JAK2-V617F mutation in patients with myeloproliferative neoplasms: Association with FLT3-ITD mutation

    Directory of Open Access Journals (Sweden)

    Čolović Milica

    2010-01-01

    Full Text Available Introduction. An acquired somatic mutation V617F in Janus kinase 2 gene (JAK2 is the cause of uncontrolled proliferation in patients with myeloproliferative neoplasms. It is known that uncontrolled myeloid cell proliferation is also provoked by alteration in other genes, e.g. mutations in receptor tyrosine kinase FLT3 gene. FLT3 represents the most frequently mutated gene in acute myeloid leukaemia. Interestingly, mutated FLT3- ITD (internal tandem duplication protein is a member of the same signalling pathway as JAK2 protein, the STAT5 signalling pathway. STAT5 activation is recognized as important for selfrenewal of haematopoetic stem cells. Objective. The aim of this study was the detection of JAK2- V617F mutation in patients with myeloproliferative neoplasms. Additionally, we investigated the presence of FLT3-ITD mutation in JAK2-V617F-positive patients in order to shed the light on the hypothesis of a similar role of these two molecular markers in haematological malignancies. Methods. Using allele-specific PCR, 61 patients with known or suspected diagnosis of myeloproliferative neoplasms were tested for the presence of JAK2-V617F mutation. Samples that were positive for JAK2 mutation were subsequently tested for the presence of FLT3-ITD mutation by PCR. Results. Eighteen of 61 analysed patients were positive for JAK2-V617F mutation. Among them, 8/18 samples were diagnosed as polycythaemia vera, and 10/18 as essential thrombocythaemia. None of JAK2-V617F-positive patient was positive for FLT3-ITD mutation. Conclusion. This study suggests that one activating mutation is sufficient for aberrant cell proliferation leading to malignant transformation of haematopoetic stem cell.

  3. Comparison of molecular biology, immunological characteristics and clinical efficacy in patients with acute myelogenous leukemia with or without FLT3-ITD gene mutation

    Directory of Open Access Journals (Sweden)

    Ting-ting LI

    2013-07-01

    Full Text Available Objective To compare the clinical and laboratory characteristics, therapeutic efficacy and prognosis of acute myelogenous leukemia (AML with or without FLT3-ITD gene mutation. Methods The clinical data of 93 AML patients, aged from 10 to 66 years, were retrospectively analyzed. Among them, 21 patients were FLT3-ITD gene (FLT3-ITD+AML group positive, and 72 patients were negative for FLT3-ITD gene (FLT3-ITD-AML group. The patients' chromosomes were examined, and mutation of FLT3-ITD and NPM1 gene and the expressions of HOX11, ETO, EVI and NPM1 gene were analyzed, along with the 2-year event-free survival and 2-year overall survival were learned. Results At primary diagnosis, the proportion of patients with WBC>100×109/L, and bleeding rate was significantly higher in FLT3-ITD+ AML group than that in FLT3-ITD-AML group (P=0.04; P=0.01, but no statistical difference was found in age, immunophenotype and chromosomal abnormality (P>0.05. The complete remission (CR rate was 28.57% in FLT3-ITD+ AML group, and it was obviously lower than that in FLT3-ITD-AML group (55.56%, P=0.013. The 2-year event-free survival was 29.2% in FLT3-ITD+ AML group, and it was significantly lower than that in FLT3-ITD-AML group (37.7%; P=0.04. Meanwhile, 33.3% of the patients in FLT3-ITD-AML group were also positive for NPM1 gene expression, and all of them did not get complete remission. However, only 1.39% of the patients expressed NPM1 gene in FLT3-ITD-AML group, but 50% of them got complete remission (P=0.022. Conclusion Patients with FLT3-ITD+AML were easily associated with high WBC counts, bleeding, lower CR rate, poor event-free survival, and poor prognosis.

  4. Impact of FLT3 internal tandem duplication on the outcome of related and unrelated hematopoietic transplantation for adult acute myeloid leukemia in first remission: A retrospective analysis

    NARCIS (Netherlands)

    S. Brunet (Salut); M. Labopin (Myriam); J. Esteve (Jordi); J.J. Cornelissen (Jan); G. Socié (Gerard); A.P. Iori (Anna); L.F. Verdonck (Leo); L. Volin (Liisa); A. Gratwohl (Alois); J. Sierra (Jorge); M. Mohty (Mohamad); V. Rocha (Vanderson)

    2012-01-01

    textabstractPurpose: Patients with acute myeloid leukemia (AML) and FLT3/internal tandem duplication (FLT3/ITD) have poor prognosis if treated with chemotherapy only. Whether this alteration also affects outcome after allogeneic hematopoietic stem-cell transplantation (HSCT) remains uncertain. Patie

  5. Relapsed Acute Myeloid Leukaemia (AML) expressing FLT-3 activating mutations. | EU Clinical Trials Register [EU Clinical Trials Register

    Lifescience Database Archive (English)

    Full Text Available rio del fármaco oral CEP-701 administrado consecutivamente con quimioterapia estándar en pacientes que han sufrido recaídas de leucem...ia mieloide aguda (LMA) mostrando mutaciones asociadas a la actividad del FLT-3 A.4

  6. An overview on the role of FLT3-tyrosine kinase receptor in acute myeloid leukemia: biology and treatment

    Directory of Open Access Journals (Sweden)

    Tiziana Grafone

    2012-04-01

    Full Text Available Hematopoiesis, the process by which the hematopoietic stem cells and progenitors differentiate into blood cells of various lineages, involves complex interactions of transcription factors that modulate the expression of downstream genes and mediate proliferation and differentiation signals. Despite the many controls that regulate hematopoiesis, mutations in the regulatory genes capable of promoting leukemogenesis may occur. The FLT3 gene encodes a tyrosine kinase receptor that plays a key role in controlling survival, proliferation and differentiation of hematopoietic cells. Mutations in this gene are critical in causing a deregulation of the delicate balance between cell proliferation and differentiation. In this review, we provide an update on the structure, synthesis and activation of the FLT3 receptor and the subsequent activation of multiple downstream signaling pathways. We also review activating FLT3 mutations that are frequently identified in acute myeloid leukemia, cause activation of more complex downstream signaling pathways and promote leukemogenesis. Finally, FLT3 has emerged as an important target for molecular therapy. We, therefore, report on some recent therapies directed against it.

  7. Preclinical Metabolism and Pharmacokinetics of SB1317 (TG02), a Potent CDK/JAK2/FLT3 Inhibitor

    NARCIS (Netherlands)

    Pasha, Mohammed Khalid; Jayaraman, Ramesh; Reddy, Venkatesh Pilla; Yeo, Pauline; Goh, Evelyn; Williams, Anthony; Goh, Kee Chuan; Kantharaj, Ethirajulu

    2012-01-01

    SB1317 (TG02) is a novel small molecule potent CDK/JAK2/FLT3 inhibitor. To evaluate full potential of this development candidate, we conducted drug metabolism and pharmacokinetic studies of this novel anti-cancer agent. SB1317 was soluble, highly permeable in Caco-2 cells, and showed >99% binding to

  8. 急性髓系白血病 FLT3基因 ITD、TKD突变的临床特征及预后比较%Clinical significance of FLT3 gene internal tandem duplication and tyrosine-kinase domain mutations in acute myeloid leukemia

    Institute of Scientific and Technical Information of China (English)

    邱桥成; 沈宏杰; 丁子轩; 何军; 薛胜利

    2016-01-01

    Objective To detect the Fms-like tyrosine kinase 3(FLT3)gene mutations in patients with primary acute myeloid leukemia,and analyze the clinical characteristics between patients with FLT3 internal tandem duplication (ITD)and Tyrosine-kinase domain(TKD)mutations. Method FLT3/ITD and FLT3/TKD gene mutations were de-tected by sequencing method in primary AML patients from July 2010 to October 2015. The clinical characteristics of 221 AML patients with FLT3/ITD,FLT3/TKD or double positive mutations were collected and analyzed,including sex,age,WHO classification,WBC,Hb,PLT,percentage of bone marrow blast,extramedullary infiltrations,and com-plete remission rate of the first course of treatment. Result Among the 221 AML patients with FLT3 gene mutation, 172 patients were FLT3/ITD,44 patients were FLT3/TKD,and 5 patients were ITD/TKD. There was no significant different variable among FLT3 mutations,including sex,age,WHO classification,WBC,Hb,PLT,percentage of bone marrow blast,extramedullary infiltrations,and complete remission rate of the first course of treatment(P>0. 05). The estimated RFS rates and OS rates at 3 years for FLT3-ITD and FLT3-TKD positive patients were 21. 4% VS 70. 5%and 25. 2% VS 72. 7%,respectively,and the FLT3-TKD positive patients had significantly longer RFS and OS than FLT3-ITD positive patients(P0.05)。 FLT3/ITD突变患者3年RFS及OS累积生存率为21.4%和25.2%,分别较 FLT3/TKD 突变患者70.5%和72.7%低,差异均有显著性( P<0.001)。结论 AML患者FLT3基因ITD突变较TKD突变比例高,3年RFS及OS累积生存率均较TKD突变低,预后差。

  9. MicroRNA-16 is down-regulated in mutated FLT3 expressing murine myeloid FDC-P1 cells and interacts with Pim-1.

    Directory of Open Access Journals (Sweden)

    Kyu-Tae Kim

    Full Text Available Activating mutations in the receptor tyrosine kinase FLT3 are one of the most frequent somatic mutations in acute myeloid leukemia (AML. Internal tandem duplications of the juxtamembrane region of FLT3 (FLT3/ITD constitutively activate survival and proliferation pathways, and are associated with a poor prognosis in AML. We suspected that alteration of small non-coding microRNA (miRNA expression in these leukemia cells is involved in the transformation process and used miRNA microarrays to determine the miRNA signature from total RNA harvested from FLT3/ITD expressing FDC-P1 cells (FD-FLT3/ITD. This revealed that a limited set of miRNAs appeared to be affected by expression of FLT3/ITD compared to the control group consisting of FDC-P1 parental cells transfected with an empty vector (FD-EV. Among differentially expressed miRNAs, we selected miR-16, miR-21 and miR-223 to validate the microarray data by quantitative real-time RT-PCR showing a high degree of correlation. We further analyzed miR-16 expression with FLT3 inhibitors in FLT3/ITD expressing cells. MiR-16 was found to be one of most significantly down-regulated miRNAs in FLT3/ITD expressing cells and was up-regulated upon FLT3 inhibition. The data suggests that miR-16 is acting as a tumour suppressor gene in FLT3/ITD-mediated leukemic transformation. Whilst miR-16 has been reported to target multiple mRNAs, computer models from public bioinformatic resources predicted a potential regulatory mechanism between miR-16 and Pim-1 mRNA. In support of this interaction, miR-16 was shown to suppress Pim-1 reporter gene expression. Further, our data demonstrated that over-expression of miR-16 mimics suppressed Pim-1 expression in FD-FLT3/ITD cells suggesting that increased miR-16 expression contributes to depletion of Pim-1 after FLT3 inhibition and that miR-16 repression may be associated with up-regulated Pim-1 in FLT3/ITD expressing cells.

  10. Prognostic significance of FLT3 internal tandem duplication in egyptian patients with acute myeloid leukemia with normal or favorable risk cytogenetics.

    Science.gov (United States)

    Shahin, Dina; Aly, Rabab; Ebrahim, Mohamed A

    2010-01-01

    Internal tandem duplication (ITD) of the FLT3 gene (FLT3/ITD) has been linked to poor outcome in acute myeloid leukemia (AML). However, the prognostic value of FLT3/ITD in various cytogenetic risk groups is still a matter of debate. The aim of this study was to evaluate the prognostic significance of FLT3/ITD in patients with de novo AML and normal or favorable risk cytogenetics (NFC-AML). Blood samples from 39 patients with AML were subjected to PCR of exons 14 and 15 of the FLT3 gene. Patients included 25 with normal cytogenetics, 8 with t(15;17), 4 with t(8;21) and 2 with inv(16). FLT3/1ITD was found in 6/39 (15.4%) patients, 4 of them showed normal cytogenetic, 1 positive for t(15;17) and 1 positive for t(8;21). Patients were M1 3/13, M2 2/12, M3 1/9, M4 0/4 and M5 0/1. The patients were followed up for a mean of 34.5 +/- 2.3 months. The complete remission (CR) rates for the FLT3/ITD+ and FLTITD- groups were 50% vs 63.6%, while the relapse rates were 50% vs 28.6% respectively. Interestingly, disease free survival (DFS) at 3 years was significantly different in studied patients: DFS was 5% in patients with FLT3/ITD+ vs 30% of patients with FLT3/ITD- (P = 0.001). Our data suggest a possible high prognostic value of FLT3/ITD in patients with normal/favorable cytogenetics.

  11. FLT3基因表达水平及内部串联重复突变与急性髓系白血病的关系及临床意义%Correlation of FLT3 gene expression level and internal tandem duplication mutation in acute myeloid leukemia and its clinical significance

    Institute of Scientific and Technical Information of China (English)

    王云贵; 刘旭辉; 梁毅; 金洁

    2008-01-01

    目的 研究FLT3基因表达水平及内部串联重复(internal tandem duplication,ITD)突变与急性髓系白血病(AML)的关系及临床意义.方法 采用实时定量RT-PCR技术检测129例AML患者治疗前后共152份骨髓标本单个核细胞FLT3 mRNA,应用RT-PCR技术检测其中75例初发未治AML患者的FLT3/ITD突变.结果 80例初发未治AML患者FLT3 mRNA表达水平为0.1041(0~33.8736),10名正常人骨髓FLT3 mRNA表达水平为0.0020(0.0006~0.0040),差异有统计学意义(P=0.001).75例初发未治AML患者检出FLT3/ITD突变者11例,突变率14.7%,FLT3/ITD突变组的FLT3 mRNA表达水平为0.2200(0.0297~33.8736),与FLT3/ITD阴性组[0.0975(0~26.2200)]比较,差异无统计学意义(P=0.093).在M,患者中,FLT3/ITD阳性者缓解率显著低于FLT3/ITD阴性者(P=0.015).FLT3/ITD阴性的非M3患者中FLT3 mRNA高表达组(表达水平>0.04)患者的化疗缓解率(37.5%)显著低于低表达组(缓解率100%).追踪观察20例患者,完全缓解组的FLT3 mRNA表达水平迅速或缓慢下降至少1个对数级,未缓解组的FLT3 mRNA表达水平无明显变化.结论 AML患者FLT3 mRNA的表达量及FLT3/ITD突变,可作为评价AML患者治疗效果、估计预后的指标,为微量残留病监测、观察AML患者病情变化提供有用工具.%Objective To evaluate the prevalence of FLT3 gene expression and internal tandem du-plication(ITD) mutation in acute myeloid leukemia (AML) patients and its clinical significance. Methods The expression level of FLT3 mRNA was detected with real-time quantitative RT-PCR (RQ-PCR) technique in 152 bone marrow samples from 129 AML patients. The ITD of the FLT3 gene (FLT3/ITD) was detected in 75 de novo AML patients by reverse transcription polymerase chain reaction (RT-PCR). Results The ex-pression levels of FLT3 mRNA was 0.0020 (0.0006 - 0.0040) in normal controls, and 0.1041 (0-33.8736) in 80 de novo AML patients(P =0.001). FLT3/ITDs were found in 11 (14.7%) of 75 de novo AML patients

  12. Comprehensive genomic analysis reveals FLT3 activation and a therapeutic strategy for a patient with relapsed adult B-lymphoblastic leukemia.

    Science.gov (United States)

    Griffith, Malachi; Griffith, Obi L; Krysiak, Kilannin; Skidmore, Zachary L; Christopher, Matthew J; Klco, Jeffery M; Ramu, Avinash; Lamprecht, Tamara L; Wagner, Alex H; Campbell, Katie M; Lesurf, Robert; Hundal, Jasreet; Zhang, Jin; Spies, Nicholas C; Ainscough, Benjamin J; Larson, David E; Heath, Sharon E; Fronick, Catrina; O'Laughlin, Shelly; Fulton, Robert S; Magrini, Vincent; McGrath, Sean; Smith, Scott M; Miller, Christopher A; Maher, Christopher A; Payton, Jacqueline E; Walker, Jason R; Eldred, James M; Walter, Matthew J; Link, Daniel C; Graubert, Timothy A; Westervelt, Peter; Kulkarni, Shashikant; DiPersio, John F; Mardis, Elaine R; Wilson, Richard K; Ley, Timothy J

    2016-07-01

    The genomic events responsible for the pathogenesis of relapsed adult B-lymphoblastic leukemia (B-ALL) are not yet clear. We performed integrative analysis of whole-genome, whole-exome, custom capture, whole-transcriptome (RNA-seq), and locus-specific genomic assays across nine time points from a patient with primary de novo B-ALL. Comprehensive genome and transcriptome characterization revealed a dramatic tumor evolution during progression, yielding a tumor with complex clonal architecture at second relapse. We observed and validated point mutations in EP300 and NF1, a highly expressed EP300-ZNF384 gene fusion, a microdeletion in IKZF1, a focal deletion affecting SETD2, and large deletions affecting RB1, PAX5, NF1, and ETV6. Although the genome analysis revealed events of potential biological relevance, no clinically actionable treatment options were evident at the time of the second relapse. However, transcriptome analysis identified aberrant overexpression of the targetable protein kinase encoded by the FLT3 gene. Although the patient had refractory disease after salvage therapy for the second relapse, treatment with the FLT3 inhibitor sunitinib rapidly induced a near complete molecular response, permitting the patient to proceed to a matched-unrelated donor stem cell transplantation. The patient remains in complete remission more than 4 years later. Analysis of this patient's relapse genome revealed an unexpected, actionable therapeutic target that led to a specific therapy associated with a rapid clinical response. For some patients with relapsed or refractory cancers, this approach may indicate a novel therapeutic intervention that could alter outcome.

  13. Adaptation of the plasma inhibitory activity assay to detect Aurora, ABL and FLT3 kinase inhibition by AT9283 in pediatric leukemia.

    Science.gov (United States)

    Podesta, Jennifer E; Sugar, Richard; Squires, Matt; Linardopoulos, Spiros; Pearson, Andrew D J; Moore, Andrew S

    2011-09-01

    Non-invasive assessment of biomarker modulation is important for evaluating targeted therapeutics, particularly in pediatrics. The plasma inhibitory activity (PIA) assay is used clinically to assess FLT3 inhibition ex vivo and guide dosing. AT9283 is a novel Aurora kinase inhibitor with secondary activity against FLT3 and ABL. We adapted the PIA assay to simultaneously detect inhibition of Aurora and FLT3 in AML, and Aurora and ABL in CML by AT9283. Furthermore, we optimized the assay for children, where limited blood volumes are available for pharmacodynamic studies. Simultaneously detecting multiple kinase inhibition may identify important mechanisms of action for novel anti-leukemic drugs.

  14. Ambit将FLT3激酶抑制剂的权力出售给Astellas

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    日本领先的制药公司Astellas Pharma已与美国私有的Ambit Bioscience公司达成价值多达3.9亿美元的协议,联合开发和商业化后者用于肿瘤学与非肿瘤学适应症的FLT3激酶抑制剂。

  15. Establishment of xenotransplantation model of human CN-AML with FLT3-ITD (mut) /NPM1 (-) in NOD/SCID mice.

    Science.gov (United States)

    Shang, Zhen; Wang, Jue; Wang, Di; Xiao, Min; Li, Tong-juan; Wang, Na; Huang, Liang; Zhou, Jian-feng

    2013-06-01

    Patients with FLT3-ITD (mut) /NPM1 (-) cytogenetically normal acute myeloid leukemia (CN-AML), as high-risk molecular group in CN-AML, are associated with a worse prognosis than other CN-AML patients. It is beneficial to generate xenotransplantation model of FLT3-ITD (mut) /NPM1 (-) CN-AML to better understand the pathogenesis and therapeutic strategies of such AML subtype. The purpose of present study was to establish the xenotransplantation model in NOD/SCID mice with FLT3-ITD (mut) /NPM1 (-) CN-AML primary cells. The FLT3-ITD (mut) /NPM1 (-) CN-AML primary cells from 3 of 7 cases were successfully transplanted into NOD/SCID mice, and human CD45 positive cells were detected in the peripheral blood, spleen and bone marrow of mice by using flow cytometry. Infiltration of human leukemia cells in various organs of mice was observed by using immunohistochemistry. Gene analysis confirmed sustained FLT3/ITD mutation without NPM1 mutation in mice. By performing serial transplantation, it was found that characteristics of the leukemia cells in secondary and tertiary generation models remained unchanged. Moreover, in vivo cytarabine administration could extend survival of NOD/SCID mice, which was consistent with clinical observation. In conclusion, we successfully established xenotransplantation model of human FLT3-ITD (mut) /NPM1 (-) CN-AML in NOD/SCID mice. The model was able to present primary disease and suitable to evaluate the curative effects of new drugs or therapy strategies.

  16. Detection of NPM1 exon 12 mutations and FLT3 – internal tandem duplications by high resolution melting analysis in normal karyotype acute myeloid leukemia

    Directory of Open Access Journals (Sweden)

    Carney Dennis A

    2008-07-01

    Full Text Available Abstract Background Molecular characterisation of normal karyotype acute myeloid leukemia (NK-AML allows prognostic stratification and potentially can alter treatment choices and pathways. Approximately 45–60% of patients with NK-AML carry NPM1 gene mutations and are associated with a favourable clinical outcome when FLT3-internal tandem duplications (ITD are absent. High resolution melting (HRM is a novel screening method that enables rapid identification of mutation positive DNA samples. Results We developed HRM assays to detect NPM1 mutations and FLT3-ITD and tested diagnostic samples from 44 NK-AML patients. Eight were NPM1 mutation positive only, 4 were both NPM1 mutation and FLT3-ITD positive and 4 were FLT3-ITD positive only. A novel point mutation Y572C (c.1715A>G in exon 14 of FLT3 was also detected. In the group with de novo NK-AML, 40% (12/29 were NPM1 mutation positive whereas NPM1 mutations were observed in 20% (3/15 of secondary NK-AML cases. Sequencing was performed and demonstrated 100% concordance with the HRM results. Conclusion HRM is a rapid and efficient method of screening NK-AML samples for both novel and known NPM1 and FLT3 mutations. NPM1 mutations can be observed in both primary and secondary NK-AML cases.

  17. Ligand inducible assembly of a DNA tetrahedron.

    Science.gov (United States)

    Dohno, Chikara; Atsumi, Hiroshi; Nakatani, Kazuhiko

    2011-03-28

    Here we show that a small synthetic ligand can be used as a key building component for DNA nanofabrication. Using naphthyridinecarbamate dimer (NCD) as a molecular glue for DNA hybridization, we demonstrate NCD-triggered formation of a DNA tetrahedron.

  18. Characterization of children with FLT3-ITD acute myeloid leukemia: a report from the AIEOP AML-2002 study group.

    Science.gov (United States)

    Manara, E; Basso, G; Zampini, M; Buldini, B; Tregnago, C; Rondelli, R; Masetti, R; Bisio, V; Frison, M; Polato, K; Cazzaniga, G; Menna, G; Fagioli, F; Merli, P; Biondi, A; Pession, A; Locatelli, F; Pigazzi, M

    2017-01-01

    Recurrent molecular markers have been routinely used in acute myeloid leukemia (AML) for risk assessment at diagnosis, whereas their post-induction monitoring still represents a debated issue. We evaluated the prognostic value and biological impact of minimal residual disease (MRD) and of the allelic ratio (AR) of FLT3-internal-tandem duplication (ITD) in childhood AML. We retrospectively screened 494 children with de novo AML for FLT3-ITD mutation, identifying 54 harboring the mutation; 51% of them presented high ITD-AR at diagnosis and had worse event-free survival (EFS, 19.2 versus 63.5% for low ITD-AR, <0.05). Forty-one percent of children with high levels of MRD after the 1st induction course, measured by a patient-specific real-time-PCR, had worse EFS (22.2 versus 59.4% in low-MRD patients, P<0.05). Next, we correlated these parameters with gene expression, showing that patients with high ITD-AR or persistent MRD had characteristic expression profiles with deregulated genes involved in methylation and acetylation. Moreover, patients with high CyclinA1 expression presented an unfavorable EFS (20.3 versus 51.2% in low CyclinA1 group, P<0.01). Our results suggest that ITD-AR levels and molecular MRD should be considered in planning clinical management of FLT3-ITD patients. Different transcriptional activation of epigenetic and oncogenic profiles may explain variability in outcome among these patients, for whom novel therapeutic approaches are desirable.

  19. H2O2 production downstream of FLT3 is mediated by p22phox in the endoplasmic reticulum and is required for STAT5 signalling.

    Directory of Open Access Journals (Sweden)

    John F Woolley

    Full Text Available The internal tandem duplication (ITD of the juxtamembrane region of the FLT3 receptor has been associated with increased reactive oxygen species (ROS generation in acute myeloid leukemia (AML. How this elevated level of ROS contributes to the leukemic phenotype, however, remains poorly understood. In this work we show that ROS in the FLT3-ITD expressing AML cell line MV4-11 is reduced by treatment with PKC412, an inhibitor of FLT3, DPI, a flavoprotein inhibitor, and VAS2870, a Nox specific inhibitor, suggesting that ROS production is both FLT3 and NADPH oxidase dependent. The majority of these ROS co-localize to the endoplasmic reticulum (ER, as determined with the H(2O(2-specific aryl-boronate dye Peroxyorange 1, which also corresponds to co-localization of p22phox. Moreover, knocking down p22phox dramatically reduces H(2O(2 after 24 hours in the ER, without affecting mitochondrial ROS. Significantly, the FLT3 inhibitor PKC412 reduces H(2O(2 in FLT3-ITD expressing cell lines (MV4-11, MOLM-13 through reduction of p22phox over 24 hours. Reduced p22phox is achieved by proteasomal degradation and is prevented upon GSK3-β inhibition. Knockdown of p22phox resulted in reduced STAT5 signalling and reduced Pim-1 levels in the cells after 24 hours. Thus, we have shown that FLT3 driven H(2O(2 production in AML cells is mediated by p22phox and is critical for STAT5 signalling.

  20. FLT3 mutations in early T-cell precursor ALL characterize a stem cell like leukemia and imply the clinical use of tyrosine kinase inhibitors.

    Directory of Open Access Journals (Sweden)

    Martin Neumann

    Full Text Available Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL has been identified as high-risk subgroup of acute T-lymphoblastic leukemia (T-ALL with a high rate of FLT3-mutations in adults. To unravel the underlying pathomechanisms and the clinical course we assessed molecular alterations and clinical characteristics in a large cohort of ETP-ALL (n = 68 in comparison to non-ETP T-ALL adult patients. Interestingly, we found a high rate of FLT3-mutations in ETP-ALL samples (n = 24, 35%. Furthermore, FLT3 mutated ETP-ALL was characterized by a specific immunophenotype (CD2+/CD5-/CD13+/CD33-, a distinct gene expression pattern (aberrant expression of IGFBP7, WT1, GATA3 and mutational status (absence of NOTCH1 mutations and a low frequency, 21%, of clonal TCR rearrangements. The observed low GATA3 expression and high WT1 expression in combination with lack of NOTCH1 mutations and a low rate of TCR rearrangements point to a leukemic transformation at the pluripotent prothymocyte stage in FLT3 mutated ETP-ALL. The clinical outcome in ETP-ALL patients was poor, but encouraging in those patients with allogeneic stem cell transplantation (3-year OS: 74%. To further explore the efficacy of targeted therapies, we demonstrate that T-ALL cell lines transfected with FLT3 expression constructs were particularly sensitive to tyrosine kinase inhibitors. In conclusion, FLT3 mutated ETP-ALL defines a molecular distinct stem cell like leukemic subtype. These data warrant clinical studies with the implementation of FLT3 inhibitors in addition to early allogeneic stem cell transplantation for this high risk subgroup.

  1. Database of ligand-induced domain movements in enzymes

    Directory of Open Access Journals (Sweden)

    Hayward Steven

    2009-03-01

    Full Text Available Abstract Background Conformational change induced by the binding of a substrate or coenzyme is a poorly understood stage in the process of enzyme catalysed reactions. For enzymes that exhibit a domain movement, the conformational change can be clearly characterized and therefore the opportunity exists to gain an understanding of the mechanisms involved. The development of the non-redundant database of protein domain movements contains examples of ligand-induced domain movements in enzymes, but this valuable data has remained unexploited. Description The domain movements in the non-redundant database of protein domain movements are those found by applying the DynDom program to pairs of crystallographic structures contained in Protein Data Bank files. For each pair of structures cross-checking ligands in their Protein Data Bank files with the KEGG-LIGAND database and using methods that search for ligands that contact the enzyme in one conformation but not the other, the non-redundant database of protein domain movements was refined down to a set of 203 enzymes where a domain movement is apparently triggered by the binding of a functional ligand. For these cases, ligand binding information, including hydrogen bonds and salt-bridges between the ligand and specific residues on the enzyme is presented in the context of dynamical information such as the regions that form the dynamic domains, the hinge bending residues, and the hinge axes. Conclusion The presentation at a single website of data on interactions between a ligand and specific residues on the enzyme alongside data on the movement that these interactions induce, should lead to new insights into the mechanisms of these enzymes in particular, and help in trying to understand the general process of ligand-induced domain closure in enzymes. The website can be found at: http://www.cmp.uea.ac.uk/dyndom/enzymeList.do

  2. FLT3 ligand preserves the uncommitted CD34+CD38- progenitor cells during cytokine prestimulation for retroviral transduction

    DEFF Research Database (Denmark)

    Nielsen, S D; Husemoen, L L; Sørensen, T U;

    2000-01-01

    Before stem cell gene therapy can be considered for clinical applications, problems regarding cytokine prestimulation remain to be solved. In this study, a retroviral vector carrying the genes for the enhanced version of green fluorescent protein (EGFP) and neomycin resistance (neo(r)) was used...

  3. Mutation Analysis of JAK2V617F, FLT3-ITD, NPM1, and DNMT3A in Chinese Patients with Myeloproliferative Neoplasms

    Directory of Open Access Journals (Sweden)

    Min Wang

    2014-01-01

    Full Text Available Since the discovery of JAK2V617F tyrosine kinase-activating mutation, several genes have been found mutated in myeloproliferative neoplasms (MPNs. FLT3-ITD, NPM1, and DNMT3A mutations frequently occurred in AML patients and have been found conferred with myeloproliferative neoplasms in mouse model. Therefore, we sought to search for mutations in JAK2V617F, FLT3-ITD, NPM1, and DNMT3A in 129 cases including 120 classic MPN cases and 9 MDS/MPN cases. JAK2V617F mutation was found in 60% of the 120 classic MPNs. However, none of the patients displayed FLT3-ITD and NPM1 mutations; only 2 patients harbored DNMT3A R882 mutation. Further studies including whole-genome sequence will be conducted to investigate the possible involvement of these genes in MPN.

  4. Potent graft-versus-leukemia effect after reduced-intensity allogeneic SCT for intermediate-risk AML with FLT3-ITD or wild-type NPM1 and CEBPA without FLT3-ITD.

    Science.gov (United States)

    Labouré, Gaëlle; Dulucq, Stéphanie; Labopin, Myriam; Tabrizi, Reza; Guérin, Estelle; Pigneux, Arnaud; Lafarge, Xavier; Leguay, Thibaut; Bouabdallah, Krimo; Dilhuydy, Marie-Sarah; Duclos, Cédric; Lascaux, Axelle; Marit, Gérald; Mahon, François-Xavier; Boiron, Jean-Michel; Milpied, Noël; Vigouroux, Stéphane

    2012-12-01

    To investigate the role of reduced-intensity allogeneic (RIC-allo) stem cell transplant (SCT) as postremission therapy in adult intermediate-risk patients with acute myelogenous leukemia (AML) with FLT3-ITD or wild-type NPM1 and CEBPA without FLT3-ITD, we conducted a single-center retrospective study between January 2001 and December 2010. Sixty-six patients were included: 37 treated with RIC-alloSCT and 29 with nonallogeneic SCT therapies. Both groups were comparable concerning age, WBC count at diagnosis, gender, karyotype, genotype, and number of courses of chemotherapy to reach complete remission (CR1). Median follow-up after CR1 was 37 months (range, 11-112 months) and 48 months (range, 9-83 months) in the allo and no-allo groups, respectively. In the allo versus no-allo groups, the 3-year cumulative incidence of relapse (CIR) rates were 25% ± 8% versus 61% ± 9%; P = .005. The 3-year nonrelapse mortality (NRM), overall survival (OS), and relapse-free survival (RFS) were 22% ± 7% versus 4% ± 4% (P = .005), 52% ± 9% versus 44% ± 10% (P = .75), and 53% ± 9% versus 35% ± 9% (P = .28), respectively. Multivariate analysis indicated that CIR was reduced by allo (hazard ratio [HR], 0.32; P = .01). A landmark analysis performed at day 185 after CR1 confirmed a lower CIR after allo. RIC-allo reduces the risk of relapse, suggesting a potent graft-versus-leukemia (GVL) effect in these patients at a high risk of relapse.

  5. Technical advance: Generation of human pDC equivalents from primary monocytes using Flt3-L and their functional validation under hypoxia.

    Science.gov (United States)

    Sekar, Divya; Brüne, Bernhard; Weigert, Andreas

    2010-08-01

    The division of labor between DC subsets is evolutionarily well-defined. mDC are efficient in antigen presentation, whereas pDC act as rheostats of the immune system. They activate NK cells, cause bystander activation of mDC, and interact with T cells to induce tolerance. This ambiguity positions pDC at the center of inflammatory diseases, such as cancer, arthritis, and autoimmune diseases. The ability to generate human mDC ex vivo made it possible to engineer them to suit therapy needs. Unfortunately, a similar, easily accessible system to generate human pDC is not available. We describe a method to generate human pDC equivalents ex vivo, termed mo-pDC from peripheral blood monocytes using Flt3-L. mo-pDC showed a characteristic pDC profile, such as high CD123 and BDCA4, but low CD86 and TLR4 surface expression and a low capacity to induce autologous lymphocyte proliferation and to phagocytose apoptotic debris in comparison with mDC. Interestingly, mo-pDC up-regulated the pDC lineage-determining transcription factor E2-2 as well as expression of BDCA2, which is under the transcriptional control of E2-2 but not its inhibitor ID2, during differentiation. mo-pDC produced high levels of IFN-alpha when pretreated overnight with TNF-alpha. Under hypoxia, E2-2 was down-regulated, and ID2 was induced in mo-pDC, whereas surface expression of MHCI, CD86, and BDCA2 was decreased. Furthermore, mo-pDC produced high levels of inflammatory cytokines when differentiated under hypoxia compared with normoxia. Hence, mo-pDC can be used to study differentiation and functions of human pDC under microenvironmental stimuli.

  6. 高压注射FLT3L-hIgGFc表达质粒诱导小鼠体内树突状细胞扩增的研究%Hydrodynamic delivery of FLT3L-hIgG Fc plasmid DNA facilitate dendritic cells development in mouse

    Institute of Scientific and Technical Information of China (English)

    卢信良; 王盛典; 任欢

    2015-01-01

    Objective Construct PTT3-FLT3L-hIgG Fc plasmid DNA,detect its protein expression levels in peripheral blood,identify the proportion and number of dendritic cells (DCs) in peripheral lymphoid organs,and evaluate the feasibility of hydrodynamic delivery instead of normal injection of protein.Methods FLT3L gene was amplified by PCR from P815 mast cell lines,and was inserted into PTT3-hIgG Fc vector.The PTT3-FLT3L-hIgG Fc plasmid was analysed by enzyme digestion and sequencing.Lymph node and spleen were harvested 9 days after hydrodynamic tail vein injection of PTT3-FLT3L-hIgG Fc and PTT3-hIgG Fc plasmids.The proportion and number of DCs were identified by flow cytometry.Results The PTT3-FLT3L-hIgG Fc plasmid was proven correctly by enzyme digestion and sequencing.High levels of FLT3L-hIgG Fc protein can be detected in peripheral blood by ELISA after hydrodynamic tail vein injection.Besides,spleen was larger in mouse and CD11 c + MHC-Ⅱ + DCs showed significant increase in peripheral lymphoid organs.Conclusion We constructed PTT3-FLT3L-hIgG Fc plasmid successfully and demonstrated that hydrodynamic tail vein injection of PTT3-FLT3L-hIgG Fc plasmids can increase DCs numbers greatly.What' s more,the effect of hydrodynamic delivery was comparable to injection of protein reported before.It indicated that we can use hydrodynamic delivery approach to achieve almost the same effect in experiments.The results further provided a foundation to produce FLT3L-hIgG Fc protein.%目的 构建重组真核表达质粒PTT3-FLT3L-hIgG Fc,鉴定其诱导机体表达蛋白FLT3L-hIgG Fc的水平以及诱导小鼠淋巴结脾脏树突状细胞(DCs)的功能,探索体内注射质粒代替注射蛋白诱导DCs方法的可行性.方法 用PCR方法从小鼠肥大细胞P815细胞系中扩增出FLT3L基因片段,连接到PTT3-hIgG Fc载体上,得到重组真核表达质粒PTT3-FLT3L-hIgG Fc;通过酶切鉴定和测序检测目的基因核苷酸序列;尾静脉高压注射PTT3-FLT3L-hIgG Fc

  7. Prognostic impact of white blood cell count in intermediate risk acute myeloid leukemia : relevance of mutated NPM1 and FLT3-ITD

    NARCIS (Netherlands)

    de Jonge, Hendrik J. M.; Valk, Peter J. M.; de Bont, Eveline S. J. M.; Schuringa, Jan Jacob; Ossenkoppele, Gert; Vellenga, Edo; Huls, Gerwin

    2011-01-01

    Background High white blood cell count at presentation is an unfavorable prognostic factor for treatment outcome in intermediate cytogenetic risk acute myeloid leukemia. Since the impact of white blood cell count on outcome of subgroups defined by the molecular markers NPMc(+) and FLT3-internal tand

  8. Detection of TET2, KRAS and CBL variants by Next Generation Sequencing and analysis of their correlation with JAK2 and FLT3 in childhood AML

    Directory of Open Access Journals (Sweden)

    Dilara Fatma Akin

    2016-04-01

    Conclusion: We found novel mutations for TET2, KRAS, and CBL. The detected variants in this article seem to be the first screening results of genes studied by NGS in childhood AML patients. Our results also showed some degree of association between FLT3-ITD and TET2, KRAS, CBL mutations.

  9. Glucocorticoid-induced TNF receptor family related protein ligand [GITR-L] is requisite for optimal functioning of regulatory CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Gongxian eLiao

    2014-02-01

    Full Text Available Glucocorticoid-Induced Tumor necrosis factor Receptor family-related protein (GITR, TNFRSF18, CD357 is constitutively expressed on regulatory T cells (Tregs and is inducible on effector T cells (Teffs. In this report, we examine the role of GITR-Ligand (GITR-L, which is expressed by antigen presenting cells, on the development and expansion of Tregs. We found that GITR-L is dispensable for the development of naturally occurring FoxP3+ Treg cells in the thymus. However, the expansion of Treg in GITR-L-/- mice is impaired after injection of the dendritic cells (DCs inducing factor Flt3 ligand. Furthermore, DCs from the liver of GITR-L-/- mice were less efficient in inducing proliferation of antigen-specific Treg cells in vitro than the same cells from WT littermates. Upon gene transfer of ovalbumin into hepatocytes of GITR-L-/- FoxP3(GFP reporter mice using adeno-associated virus (AAV8-OVA the number of antigen-specific Treg in liver and spleen is reduced. The reduced number of Tregs resulted in an increase in the number of ovalbumin specific CD8+ T effector cells. This is highly significant because proliferation of antigen specific CD8+ cells itself is dependent on the presence of GITR-L, as shown by in vitro experiments and by adoptive transfers into GITR-L-/-Rag-/- and Rag-/- mice that had received AAV8-OVA. Surprisingly, administering αCD3 significantly reduced the numbers of FoxP3+ Treg cells in the liver and spleen of GITR-L-/- but not WT mice. Because soluble Fc-GITR-L partially rescues αCD3 induced in vitro depletion of the CD103+ subset of FoxP3+CD4+ Treg cells, we conclude that expression of GITR-L by antigen presenting cells is requisite for optimal Treg-mediated regulation of immune responses including those in response during gene transfer.

  10. Internal tandem duplication of the FLT3 gene confers poor overall survival in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline-based chemotherapy: an International Consortium on Acute Promyelocytic Leukemia study.

    Science.gov (United States)

    Lucena-Araujo, Antonio R; Kim, Haesook T; Jacomo, Rafael H; Melo, Raul A; Bittencourt, Rosane; Pasquini, Ricardo; Pagnano, Katia; Fagundes, Evandro M; Chauffaille, Maria de Lourdes; Chiattone, Carlos S; Lima, Ana Silvia; Ruiz-Argüelles, Guillermo; Undurraga, Maria Soledad; Martinez, Lem; Kwaan, Hau C; Gallagher, Robert; Niemeyer, Charlotte M; Schrier, Stanley L; Tallman, Martin S; Grimwade, David; Ganser, Arnold; Berliner, Nancy; Ribeiro, Raul C; Lo-Coco, Francesco; Löwenberg, Bob; Sanz, Miguel A; Rego, Eduardo M

    2014-12-01

    Activating internal tandem duplication (ITD) mutations in the fms-like tyrosine kinase 3 (FLT3) gene (FLT3-ITD) are associated with poor outcome in acute myeloid leukemia, but their prognostic impact in acute promyelocytic leukemia (APL) remains controversial. Here, we screened for FLT3-ITD mutations in 171 APL patients, treated with all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy. We identified FLT3-ITD mutations in 35 patients (20 %). FLT3-ITD mutations were associated with higher white blood cell counts (P < 0.0001), relapse-risk score (P = 0.0007), higher hemoglobin levels (P = 0.0004), higher frequency of the microgranular morphology (M3v) subtype (P = 0.03), and the short PML/RARA (BCR3) isoform (P < 0.0001). After a median follow-up of 38 months, FLT3-ITD(positive) patients had a lower 3-year overall survival rate (62 %) compared with FLT3-ITD(negative) patients (82 %) (P = 0.006). The prognostic impact of FLT3-ITD on survival was retained in multivariable analysis (hazard ratio: 2.39, 95 % confidence interval [CI] 1.17-4.89; P = 0.017). Nevertheless, complete remission (P = 0.07), disease-free survival (P = 0.24), and the cumulative incidence of relapse (P = 0.94) rates were not significantly different between groups. We can conclude that FLT3-ITD mutations are associated with several hematologic features in APL, in particular with high white blood cell counts. In addition, FLT3-ITD may independently predict a shorter survival in patients with APL treated with ATRA and anthracycline-based chemotherapy.

  11. Misfolded N-CoR is linked to the ectopic reactivation of CD34/Flt3-based stem-cell phenotype in promyelocytic and monocytic acute myeloid leukemia

    Directory of Open Access Journals (Sweden)

    Dawn Sijin Nin

    2015-10-01

    Full Text Available Nuclear receptor co-repressor (N-CoR is the key component of generic co-repressor complex essential for the transcriptional control of genes involved in cellular hemostasis. We have recently reported that N-CoR actively represses Flt3, a key factor of hematopoietic stem cells (HSC self-renewal and growth; and that de-repression of Flt3 by the misfolded N-CoR plays important role in the pathogenesis of promyelocytic and monocytic acute myeloid leukemia (AML. The leukemic cells derived from the promyelocytic and monocytic AML are distinctly characterized by the ectopic reactivation of stem cell phenotypes in relatively committed myeloid compartment. However, the molecular mechanism underlying this phenomenon is not known. Here, we report that N-CoR function is essential for the commitment of primitive hematopoietic cells to the cells of myeloid lineage, and that loss of N-CoR function due to misfolding is linked to the ectopic reactivation of generic stem cell phenotypes in promyelocytic and monocytic AML. Analysis of N-CoR and Flt3 transcripts in mouse hematopoietic cells revealed a positive correlation between N-CoR level and the commitment of myeloid cells and an inverse correlation between N-CoR and Flt3 levels in primitive as well as committed myeloid cells. Enforced N-CoR expression in mouse HSCs inhibited their growth and self-renewal potentials and promoted maturation towards cells of myeloid lineage, suggesting a role of N-CoR in the commitment of cells of myeloid lineage. In contrast to AML cells with natively folded N-CoR, primary and secondary promyelocytic and monocytic AML cells harboring the misfolded N-CoR were highly positive for Flt3 and myeloid antigen based HSC marker CD34. Genetic and therapeutic restoration of N-CoR conformation significantly down-regulated the CD34 levels in monocytic AML cells, suggesting an important role of N-CoR in the suppression of CD34 based hematopoietic stem cell phenotypes. These finding

  12. Selective inhibition of FLT3 by gilteritinib in relapsed or refractory acute myeloid leukaemia: a multicentre, first-in-human, open-label, phase 1-2 study.

    Science.gov (United States)

    Perl, Alexander E; Altman, Jessica K; Cortes, Jorge; Smith, Catherine; Litzow, Mark; Baer, Maria R; Claxton, David; Erba, Harry P; Gill, Stan; Goldberg, Stuart; Jurcic, Joseph G; Larson, Richard A; Liu, Chaofeng; Ritchie, Ellen; Schiller, Gary; Spira, Alexander I; Strickland, Stephen A; Tibes, Raoul; Ustun, Celalettin; Wang, Eunice S; Stuart, Robert; Röllig, Christoph; Neubauer, Andreas; Martinelli, Giovanni; Bahceci, Erkut; Levis, Mark

    2017-08-01

    Internal tandem duplication mutations in FLT3 are common in acute myeloid leukaemia and are associated with rapid relapse and short overall survival. The clinical benefit of FLT3 inhibitors in patients with acute myeloid leukaemia has been limited by rapid generation of resistance mutations, particularly in codon Asp835 (D835). We aimed to assess the highly selective oral FLT3 inhibitor gilteritinib in patients with relapsed or refractory acute myeloid leukaemia. In this phase 1-2 trial, we enrolled patients aged 18 years or older with acute myeloid leukaemia who either were refractory to induction therapy or had relapsed after achieving remission with previous treatment. Patients were enrolled into one of seven dose-escalation or dose-expansion cohorts assigned to receive once-daily doses of oral gilteritinib (20 mg, 40 mg, 80 mg, 120 mg, 200 mg, 300 mg, or 450 mg). Cohort expansion was based on safety and tolerability, FLT3 inhibition in correlative assays, and antileukaemic activity. Although the presence of an FLT3 mutation was not an inclusion criterion, we required ten or more patients with locally confirmed FLT3 mutations (FLT3(mut+)) to be enrolled in expansion cohorts at each dose level. On the basis of emerging findings, we further expanded the 120 mg and 200 mg dose cohorts to include FLT3(mut+) patients only. The primary endpoints were the safety, tolerability, and pharmacokinetics of gilteritinib. Safety and tolerability were assessed in the safety analysis set (all patients who received at least one dose of gilteritinib). Responses were assessed in the full analysis set (all patients who received at least one dose of study drug and who had at least one datapoint post-treatment). Pharmacokinetics were assessed in a subset of the safety analysis set for which sufficient data for concentrations of gilteritinib in plasma were available to enable derivation of one or more pharmacokinetic variables. This study is registered with ClinicalTrials.gov, number

  13. TET2 gene mutation is unfavorable prognostic factor in cytogenetically normal acute myeloid leukemia patients with NPM1+ and FLT3-ITD - mutations.

    Science.gov (United States)

    Tian, Xiaopeng; Xu, Yang; Yin, Jia; Tian, Hong; Chen, Suning; Wu, Depei; Sun, Aining

    2014-07-01

    Cytogenetically normal acute myeloid leukemia (cn-AML) is a group of heterogeneous diseases. Gene mutations are increasingly used to assess the prognosis of cn-AML patients and guide risk-adapted treatment. In the present study, we analyzed the molecular genetics characteristics of 373 adult cn-AML patients and explored the relationship between TET2 gene mutations or different genetic mutation patterns and prognosis. We found that 16.1 % of patients had TET2 mutations, 31.6 % had FLT3 internal tandem duplications (ITDs), 6.2 % had FLT3 tyrosine kinase domain mutations, 2.4 % had c-KIT mutations, 37.8 % had NPM1 mutations, 11.3 % had WT1 mutations, 5.9 % had RUNX1 mutations, 11.5 % had ASXL1 mutations, 3.8 % had MLL-PTDs, 7.8 % had IDH1 mutations, 7.8 % had NRAS mutations, 12.3 % had IDH2 mutations, 1.6 % had EZH2 mutations, and 14.7 % had DNMT3A mutations, while none had CBL mutations. Gene mutations were detected in 76.94 % (287/373) of all patients. In the NPM1m(+) patients, those with TET2 mutations were associated with a shorter median overall survival (OS) as compared to TET2 wild-type (wt) patients (9.9 vs. 27.0 months, respectively; P = 0.023); Interestingly, the TET2 mutation was identified as an unfavorable prognostic factor and was closely associated with a shorter median OS as compared to TET2-wt (9.5 vs. 32.2 months, respectively; P = 0.013) in the NPM1m(+)/FLT3-ITDm(-) patient group. Thus, identification of TET2 combined with classic NPM1 and FLT3-ITD mutations allowed us to stratify cn-AML into distinct subtypes.

  14. FLT3/ITD基因突变在不同血液肿瘤患者的表达及其临床意义%Detection of FLT3/ITD gene mutations in patients with hematologic malignancy and their clinical Significance

    Institute of Scientific and Technical Information of China (English)

    Bing Xu; Guoshu Chen; Xiaodan Luo; Jiahong Tang

    2009-01-01

    Objective:To analyze Fms-like tyrosine kinase 3(FLT3)/intemal-tandem duplications(ITD)murations in various kinds of hematologic malignancy patients.Methods:FLT3/ITD gene mutations were detected by polymerase chain reaction (PCR)in 103 acute myeloid leukemia(AML)cases,63 acute lymphocytic leukemia(ALL)cases,53 chronic myelogenous leukemia(CML)cases in chronic phase(CML-CP),34 CML cases in biast crisis(CML-BC),11 chronic lymphatic leukemia(CLL)cases,36 myelodysplastic syndrome (MDS)cases,9 multiple myeloma(MM)cases and 13 non-hodgkin's lymphoma (NHL)cases with marrow infiltration.Results:The expressions of FLT3/ITD gene mutations were detected in 22.3% AML cases.in 6.5%CML-BC cases.in 5.6%MDS cases and in 2.6%ALL cases.The two ALL cases with FLT3/ITD mutation were diagnosed as ALL-L2 with morphology and both with myeloid antigen expression,but finally were diagnosed as acute mixed-lineage leukemia after immunology examination.FLT3/ITD gene muIations were not detected in CML-CP,MM.NHL and CLL cases.In the 23 AML patients with FLT3/ITD gene mutation,including 2 of 8 M1(2.5%),8 of 33 M2(24-2%),7 of 24 M3(29.3%),2 of 11 M4(18.2%).3 of 21 M5(14.3%),1 of 5 M6(20%),and 0 of 1 M7 cases,and there were no significant differences in the positive rates of FLT3/ITD mutations between the FAB subtypes(P>0.05).Statistical analyses showed that in AML patients,FLT3/ITD was associated with a higher pefipheral blood white cell(WBC)counts[(41.23±32.56)x 100/L vs (11.36±9.89)x109/L(P<0.01)],higher percentage of bone marrow blast cells[(72.78±21.79)%vs(51.26±20.78)%(P<0.05)],and higher cumulative relapse rates(63.6%vs 27.7%,P<0.025)than those negative.Conclusion:FLT3/ITD gene mutation mainly pccurred in AML patients.and might be a strong prognostic factor which was associated with high peripheral WBC counts.bone marrow blast cell proportion and a increased relapse risk in AML.Detection of FLT3/ITD gene mutation might provide insights to explore a more accurate genotyping of

  15. Programmed Death Ligand 2 in Cancer-Induced Immune Suppression

    Directory of Open Access Journals (Sweden)

    Esdy N. Rozali

    2012-01-01

    Full Text Available Inhibitory molecules of the B7/CD28 family play a key role in the induction of immune tolerance in the tumor microenvironment. The programmed death-1 receptor (PD-1, with its ligands PD-L1 and PD-L2, constitutes an important member of these inhibitory pathways. The relevance of the PD-1/PD-L1 pathway in cancer has been extensively studied and therapeutic approaches targeting PD-1 and PD-L1 have been developed and are undergoing human clinical testing. However, PD-L2 has not received as much attention and its role in modulating tumor immunity is less clear. Here, we review the literature on the immunobiology of PD-L2, particularly on its possible roles in cancer-induced immune suppression and we discuss the results of recent studies targeting PD-L2 in cancer.

  16. Death induced by CD95 or CD95 ligand elimination.

    Science.gov (United States)

    Hadji, Abbas; Ceppi, Paolo; Murmann, Andrea E; Brockway, Sonia; Pattanayak, Abhinandan; Bhinder, Bhavneet; Hau, Annika; De Chant, Shirley; Parimi, Vamsi; Kolesza, Piotre; Richards, Joanne; Chandel, Navdeep; Djaballah, Hakim; Peter, Marcus E

    2014-04-10

    CD95 (Fas/APO-1), when bound by its cognate ligand CD95L, induces cells to die by apoptosis. We now show that elimination of CD95 or CD95L results in a form of cell death that is independent of caspase-8, RIPK1/MLKL, and p53, is not inhibited by Bcl-xL expression, and preferentially affects cancer cells. All tumors that formed in mouse models of low-grade serous ovarian cancer or chemically induced liver cancer with tissue-specific deletion of CD95 still expressed CD95, suggesting that cancer cannot form in the absence of CD95. Death induced by CD95R/L elimination (DICE) is characterized by an increase in cell size, production of mitochondrial ROS, and DNA damage. It resembles a necrotic form of mitotic catastrophe. No single drug was found to completely block this form of cell death, and it could also not be blocked by the knockdown of a single gene, making it a promising way to kill cancer cells. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Death Induced by CD95 or CD95 Ligand Elimination

    Directory of Open Access Journals (Sweden)

    Abbas Hadji

    2014-04-01

    Full Text Available CD95 (Fas/APO-1, when bound by its cognate ligand CD95L, induces cells to die by apoptosis. We now show that elimination of CD95 or CD95L results in a form of cell death that is independent of caspase-8, RIPK1/MLKL, and p53, is not inhibited by Bcl-xL expression, and preferentially affects cancer cells. All tumors that formed in mouse models of low-grade serous ovarian cancer or chemically induced liver cancer with tissue-specific deletion of CD95 still expressed CD95, suggesting that cancer cannot form in the absence of CD95. Death induced by CD95R/L elimination (DICE is characterized by an increase in cell size, production of mitochondrial ROS, and DNA damage. It resembles a necrotic form of mitotic catastrophe. No single drug was found to completely block this form of cell death, and it could also not be blocked by the knockdown of a single gene, making it a promising way to kill cancer cells.

  18. Importância da detecção das mutações no gene FLT3 e no gene NPM1 na leucemia mieloide aguda - Classificação da Organização Mundial de Saúde 2008 Importance of detecting FLT3 and NPM1 gene mutations in acute myeloid leukemia -World Health Organization Classification 2008

    Directory of Open Access Journals (Sweden)

    Marley Aparecida Licínio

    2010-01-01

    Full Text Available As leucemias mieloides agudas (LMA constituem um grupo de neoplasias malignas caracterizadas pela proliferação descontrolada de células hematopoéticas, decorrente de mutações que podem ocorrer em diferentes fases da diferenciação de células precursoras mieloides. Em 2008, a Organização Mundial da Saúde (OMS-2008 publicou uma nova classificação para neoplasias do sistema hematopoético e linfoide. De acordo com essa classificação, para um diagnóstico mais preciso e estratificação de prognóstico de pacientes com leucemias mieloides agudas, devem-se pesquisar mutações nos genes FLT3 e NPM1. Sabe-se que a presença de mutações no gene FLT3 é de prognóstico desfavorável e que as mutações no gene NPM1 do tipo A são de prognóstico favorável. Assim, nos países desenvolvidos, a análise das mutações no gene FLT3 e NPM1 tem sido considerada como um fator de prognóstico importante na decisão terapêutica em pacientes com diagnóstico de leucemias mieloides agudas. Considerando essas informações, é de extrema importância a análise das mutações no gene FLT3 (duplicação interna em tandem - DIT - e mutação pontual D835 e no gene NPM1 como marcadores moleculares para o diagnóstico, o prognóstico e a monitoração de doença residual mínima em pacientes com leucemias mieloides agudas.Acute myeloid leukemia (AML is a group of malignancies characterized by uncontrolled proliferation of hematopoietic cells resulting from mutations that occur at different stages in the differentiation of myeloid precursor cells. In 2008, the World Health Organization (WHO-2008 published a new classification for cancers of the hematopoietic and lymphoid system. According to this classification, FLT3 and NPM1 gene mutations should be investigated for a more precise diagnosis and prognostic stratification of AML patients. It is well known that the presence of FLT3 gene mutations is considered an unfavorable prognostic factor and type

  19. Ligand-induced TCR down-regulation is not dependent on constitutive TCR cycling

    DEFF Research Database (Denmark)

    Dietrich, Jes; Menné, Charlotte; Lauritsen, Jens Peter H

    2002-01-01

    TCR internalization takes place both in resting T cells as part of constitutive TCR cycling, after PKC activation, and during TCR triggering. It is still a matter of debate whether these pathways represent distinct pathways. Thus, some studies have indicated that ligand-induced TCR internalization......, we next studied ligand-induced internalization in cells with abolished constitutive TCR cycling. We found that ligand-induced TCR internalization was not dependent on constitutive TCR internalization. Likewise, constitutive internalization and recycling of the TCR were independent of an intact ligand...... is regulated by mechanisms distinct from those involved in constitutive internalization, whereas other studies have suggested that the ligand-induced TCR internalization pathway is identical with the constitutive pathway. To resolve this question, we first identified requirements for constitutive TCR cycling...

  20. Ex vivo Flt3L stimulation of CD8α+ dendritic cells derived from mouse bone marrow and analysis of their maturity%Flt3L刺激体外培养小鼠骨髓源CD8α+树突状细胞及其成熟状态分析

    Institute of Scientific and Technical Information of China (English)

    张东辉; 侯敏; 陈莹莹; 王铖芸; 张凡; 高雅楠; 陈琳; 季旻珺; 吴观陵

    2014-01-01

    目的 建立体外快速制备大量具有免疫活性的小鼠骨髓来源不成熟CD8α DCs方法.方法 实验分2组.Flt3L组:将小鼠骨髓前体细胞用含终浓度为100 ng/ml Flt3L的BMDC培养基混悬后接种于细胞培养皿中,每平皿10ml,37C培养至第7d收集细胞;GM-CSF+IL-4组:将骨髓前体细胞用含终浓度为20 ng/ml GM-CSF、5 ng/ml IL-4的BMDC培养基混悬后接种于细胞培养皿中,每平皿 10 ml,分别于37 C培养第3d和第5d半量换液,培养第7d收集细胞,采用磁选法分离CD11c+ BMDCs,用流式细胞仪检测.结果 Flt3L刺激组CD11c+BMDCs得率为(95.07±0.09)%,GM-CSF+IL-4刺激组为(83.97±0.43)%,差异有统计学意义(P<0.01).Fh3L刺激组CD11c+ CD8α+BMDCs得率为(9.83±0.33)%,GM-CSF+IL-4刺激组刺激组为(4.06±0.17)%,差异有统计学意义(P< 0.01).Flt3L刺激组CD11c+CD8α+ BMDCs表面几乎不表达CD40、CD80、CD86,仪低表达MHCⅠ、MHCⅡ,处于朱成熟阶段.结论 采用Flt3L刺激小鼠骨髓前体细胞的方法可获得大量未成熟的CD11c+CD8α+ BMDCs,方法简单,得率较高,为开展CD8α+ DCs相关基础和临床研究奠定了基础.

  1. Ligand-Induced Stability of Gold Nanoclusters: Thiolate versus Selenolate.

    Science.gov (United States)

    Kurashige, Wataru; Yamaguchi, Masaki; Nobusada, Katsuyuki; Negishi, Yuichi

    2012-09-20

    Thiolate-protected gold nanoclusters have attracted considerable attention as building blocks for new functional materials and have been extensively researched. Some studies have reported that changing the ligand of these gold nanoclusters from thiolate to selenolate increases cluster stability. To confirm this, in this study, we compare the stabilities of precisely synthesized [Au25(SC8H17)18](-) and [Au25(SeC8H17)18](-) against degradation in solution, thermal dissolution, and laser fragmentation. The results demonstrate that changing the ligand from thiolate to selenolate increases cluster stability in reactions involving dissociation of the gold-ligand bond but reduces cluster stability in reactions involving intramolecular dissociation of the ligand. These results reveal that using selenolate ligands makes it possible to produce gold clusters that are more stable against degradation in solution than thiolate-protected gold nanoclusters.

  2. Double CEBPA mutations are prognostically favorable in non-M3 acute myeloid leukemia patients with wild-type NPM1 and FLT3-ITD.

    Science.gov (United States)

    Wen, Xiang-Mei; Lin, Jiang; Yang, Jing; Yao, Dong-Ming; Deng, Zhao-Qun; Tang, Chun-Yan; Xiao, Gao-Fei; Yang, Lei; Ma, Ji-Chun; Hu, Jia-Bo; Qian, Wei; Qian, Jun

    2014-01-01

    This study is aimed to investigate the pattern of CEBPA mutations and its clinical significance in Chinese non-M3 acute myeloid leukemia (AML) patients. The entire coding region of CEBPA gene was amplified by PCR and then sequenced in samples from 233 non-M3 AML patients. Fifty mutations were identified in 37 (15.8%) patients with eleven (4.7%) double mutated CEBPA (dmCEBPA) and twenty-six (11.1%) single mutated CEBPA (smCEBPA). dmCEBPA was exclusively observed in M1 and M2 subtypes of FAB classification (P = 0.008), whereas smCEBPA occurred in almost all subtypes (P = 0.401). Patients with dmCEBPA had significantly younger age and higher WBC counts than those with wtCEBPA (P = 0.016 and 0.043, respectively). Both dmCEBPA and smCEBPA were mainly present in cytogenetically normal patients. Patients with dmCEBPA achieved higher rate of complete (CR) than wtCEBPA patients (88% vs. 51%, P = 0.037), whereas smCEBPA and wtCEBPA groups are similar (47% vs. 51%, P = 0.810). Patients with dmCEBPA had a superior overall survival (OS) compared with patients with wtCEBPA (P = 0.033), whereas patients with smCEBPA had a similar OS as patients with wtCEBPA (P = 0.976). dmCEBPA but not smCEBPA was also associated with favorable outcome in patients with wild-type NPM1 and FLT3-ITD (NPM1(wt)FLT3-ITD(wt) ). Our data confirm that dmCEBPA but not smCEBPA is prognostically favorable in NPM1(wt)FLT3-ITD(wt) AML, and suggest that the entity AML with mutated CEBPA should be definitely designated as AML with dmCEBPA in WHO classification and smCEBPA should be excluded from the favorable risk of molecular abnormalities.

  3. Early Death in Two Patients with Acute Promyelocytic Leukemia Presenting the bcr3 Isoform, FLT3-ITD Mutation, and Elevated WT1 Level

    Directory of Open Access Journals (Sweden)

    Marianna Greco

    2013-01-01

    Full Text Available Despite major advances in the treatment of acute promyelocytic leukemia (APL, the problem of early death (ED remains unsolved. Alongside the currently known clinical and hematological risk factors, prognostic significance has been attributed to internal tandem duplication mutations of the fms-like tyrosine kinase-3 (FLT3-ITD, hypogranular variant morphology, and the bcr-3 isoform of PML-RARα. We describe premature death of two patients with the hypogranular variant of APL who presented remarkably high expression levels of Wilms' tumor gene (WT1. Our results point to WT1 as an important prognostic factor of ED that needs to be promptly evaluated in all newly diagnosed cases of APL.

  4. Roscovitine sensitizes leukemia and lymphoma cells to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis

    OpenAIRE

    Molinsky, J.; Klánová, M.; Koc, M; Beranová, L. (Lenka); Anděra, L. (Ladislav); Ludvíková, Z.; Bohmova, M.; Gasova, Z.; Strnad, M.; Ivánek, R. (Robert); Trněný, M.; Nečas, E.; Živný, J.; Klener, P.

    2013-01-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand with selective antitumor activity. However, many primary tumors are TRAIL resistant. Previous studies reported that roscovitine, a cyclin-dependent kinase inhibitor, sensitized various solid cancer cells to TRAIL. We show that roscovitine and TRAIL demonstrate synergistic cytotoxicity in hematologic malignant cell lines and primary cells. Pretreatment of TRAIL-resistant leukemia cells with roscovitine induced en...

  5. Ligand induced conformational changes of the human serotonin transporter revealed by molecular dynamics simulations.

    Directory of Open Access Journals (Sweden)

    Heidi Koldsø

    Full Text Available The competitive inhibitor cocaine and the non-competitive inhibitor ibogaine induce different conformational states of the human serotonin transporter. It has been shown from accessibility experiments that cocaine mainly induces an outward-facing conformation, while the non-competitive inhibitor ibogaine, and its active metabolite noribogaine, have been proposed to induce an inward-facing conformation of the human serotonin transporter similar to what has been observed for the endogenous substrate, serotonin. The ligand induced conformational changes within the human serotonin transporter caused by these three different types of ligands, substrate, non-competitive and competitive inhibitors, are studied from multiple atomistic molecular dynamics simulations initiated from a homology model of the human serotonin transporter. The results reveal that diverse conformations of the human serotonin transporter are captured from the molecular dynamics simulations depending on the type of the ligand bound. The inward-facing conformation of the human serotonin transporter is reached with noribogaine bound, and this state resembles a previously identified inward-facing conformation of the human serotonin transporter obtained from molecular dynamics simulation with bound substrate, but also a recently published inward-facing conformation of a bacterial homolog, the leucine transporter from Aquifex Aoelicus. The differences observed in ligand induced behavior are found to originate from different interaction patterns between the ligands and the protein. Such atomic-level understanding of how an inhibitor can dictate the conformational response of a transporter by ligand binding may be of great importance for future drug design.

  6. Ligand induced conformational changes of the human serotonin transporter revealed by molecular dynamics simulations.

    Science.gov (United States)

    Koldsø, Heidi; Autzen, Henriette Elisabeth; Grouleff, Julie; Schiøtt, Birgit

    2013-01-01

    The competitive inhibitor cocaine and the non-competitive inhibitor ibogaine induce different conformational states of the human serotonin transporter. It has been shown from accessibility experiments that cocaine mainly induces an outward-facing conformation, while the non-competitive inhibitor ibogaine, and its active metabolite noribogaine, have been proposed to induce an inward-facing conformation of the human serotonin transporter similar to what has been observed for the endogenous substrate, serotonin. The ligand induced conformational changes within the human serotonin transporter caused by these three different types of ligands, substrate, non-competitive and competitive inhibitors, are studied from multiple atomistic molecular dynamics simulations initiated from a homology model of the human serotonin transporter. The results reveal that diverse conformations of the human serotonin transporter are captured from the molecular dynamics simulations depending on the type of the ligand bound. The inward-facing conformation of the human serotonin transporter is reached with noribogaine bound, and this state resembles a previously identified inward-facing conformation of the human serotonin transporter obtained from molecular dynamics simulation with bound substrate, but also a recently published inward-facing conformation of a bacterial homolog, the leucine transporter from Aquifex Aoelicus. The differences observed in ligand induced behavior are found to originate from different interaction patterns between the ligands and the protein. Such atomic-level understanding of how an inhibitor can dictate the conformational response of a transporter by ligand binding may be of great importance for future drug design.

  7. Programmed death ligand 2 in cancer-induced immune suppression.

    NARCIS (Netherlands)

    Rozali, E.N.; Hato, S.V.; Robinson, B.W.; Lake, R.A.; Lesterhuis, W.J.

    2012-01-01

    Inhibitory molecules of the B7/CD28 family play a key role in the induction of immune tolerance in the tumor microenvironment. The programmed death-1 receptor (PD-1), with its ligands PD-L1 and PD-L2, constitutes an important member of these inhibitory pathways. The relevance of the PD-1/PD-L1 pathw

  8. Small molecule, non-peptide p75 ligands inhibit Abeta-induced neurodegeneration and synaptic impairment.

    Directory of Open Access Journals (Sweden)

    Tao Yang

    Full Text Available The p75 neurotrophin receptor (p75(NTR is expressed by neurons particularly vulnerable in Alzheimer's disease (AD. We tested the hypothesis that non-peptide, small molecule p75(NTR ligands found to promote survival signaling might prevent Abeta-induced degeneration and synaptic dysfunction. These ligands inhibited Abeta-induced neuritic dystrophy, death of cultured neurons and Abeta-induced death of pyramidal neurons in hippocampal slice cultures. Moreover, ligands inhibited Abeta-induced activation of molecules involved in AD pathology including calpain/cdk5, GSK3beta and c-Jun, and tau phosphorylation, and prevented Abeta-induced inactivation of AKT and CREB. Finally, a p75(NTR ligand blocked Abeta-induced hippocampal LTP impairment. These studies support an extensive intersection between p75(NTR signaling and Abeta pathogenic mechanisms, and introduce a class of specific small molecule ligands with the unique ability to block multiple fundamental AD-related signaling pathways, reverse synaptic impairment and inhibit Abeta-induced neuronal dystrophy and death.

  9. Solvent fluctuations induce non-Markovian kinetics in hydrophobic pocket-ligand binding

    CERN Document Server

    Weiß, R Gregor; Dzubiella, Joachim

    2016-01-01

    We investigate the impact of water fluctuations on the key-lock association kinetics of a hydrophobic ligand (key) binding to a hydrophobic pocket (lock) by means of a minimalistic stochastic model system. It describes the collective hydration behavior of the pocket by bimodal fluctuations of a water-pocket interface that dynamically couples to the diffusive motion of the approaching ligand via the hydrophobic interaction. This leads to a set of overdamped Langevin equations in 2D-coordinate-space, that is Markovian in each dimension. Numerical simulations demonstrate locally increased friction of the ligand, decelerated binding kinetics, and local non-Markovian (memory) effects in the ligand's reaction coordinate as found previously in explicit-water molecular dynamics studies of model hydrophobic pocket-ligand binding [1,2]. Our minimalistic model elucidates the origin of effectively enhanced friction in the process that can be traced back to long-time decays in the force-autocorrelation function induced by...

  10. Light-induced regulation of ligand-gated channel activity.

    Science.gov (United States)

    Bregestovski, Piotr; Maleeva, Galyna; Gorostiza, Pau

    2017-08-31

    The control of ligand-gated receptors with light using photochromic compounds has evolved from the first handcrafted examples to accurate, engineered receptors, whose development is supported by rational design, high-resolution protein structures, comparative pharmacology and molecular biology manipulations. Photoswitchable regulators have been designed and characterized for a large number of ligand-gated receptors in the mammalian nervous system, including nicotinic acetylcholine, glutamate and GABA receptors. They provide a well-equipped toolbox to investigate synaptic and neuronal circuits in all-optical experiments. This focused review discusses the design and properties of these photoswitches, their applications and shortcomings and future perspectives in the field. © 2017 The British Pharmacological Society.

  11. Acetone and the precursor ligand acetylacetone : distinctly different electron beam induced decomposition?

    NARCIS (Netherlands)

    Warneke, Jonas; Van Dorp, Willem F.; Rudolf, Petra; Stano, Michal; Papp, Peter; Matejcik, Stefan; Borrmann, Tobias; Swiderek, Petra

    2015-01-01

    In focused electron beam induced deposition (FEBID) acetylacetone plays a role as a ligand in metal acetylacetonate complexes. As part of a larger effort to understand the chemical processes in FEBID, the electron-induced reactions of acetylacetone were studied both in condensed layers and in the ga

  12. A comparative study examining the cytotoxicity of inducible gene expression system ligands in different cell types.

    Science.gov (United States)

    Xie, Jinger; Nair, Ayyappan; Hermiston, Terry W

    2008-02-01

    Inducible gene expression systems are being used in many in vitro and in vivo applications for target discovery, target validation and as components in exploratory therapeutic agents. Ideally, the ligands, which activate the systems, are benign so that the effects can be strictly attributed to the induced protein. As a first step to defining the potential effects of these inducers, we tested three of them, doxycycline, muristerone A and mifepristone (for tet-, ecdysone- and progesterone antagonist-inducible systems respectively), for toxicity across a panel of normal cells and cancer cell lines. In contrast to both muristerone A and mifepristone that showed no significant toxicity on any of the tested cells, we observed that doxycycline induced cell death in selected cancer and primary cell lines. The different susceptibility of cell lines to the ligands commonly used in these inducible systems suggests that it is important to consider the effects of the inducers prior to their use in experimental in vitro cell culture systems.

  13. Lipoteichoic acid induces unique inflammatory responses when compared to other toll-like receptor 2 ligands.

    Directory of Open Access Journals (Sweden)

    Elizabeth M Long

    Full Text Available Toll-like receptors (TLRs recognize evolutionarily-conserved molecular patterns originating from invading microbes. In this study, we were interested in determining if microbial ligands, which use distinct TLR2-containing receptor complexes, represent unique signals to the cell and can thereby stimulate unique cellular responses. Using the TLR2 ligands, R-FSL1, S-FSL1, Pam2CSK4, Pam3CSK4, and lipoteichoic acid (LTA, we demonstrate that these ligands activate NF-kappaB and MAP Kinase pathways with ligand-specific differential kinetics in murine macrophages. Most strikingly, LTA stimulation of these pathways was substantially delayed when compared with the other TLR2 ligands. These kinetics differences were associated with a delay in the LTA-induced expression of a subset of genes as compared with another TLR2 ligand, R-FSL1. However, this did not translate to overall differences in gene expression patterns four hours following stimulation with different TLR2 ligands. We extended this study to evaluate the in vivo responses to distinct TLR2 ligands using a murine model of acute inflammation, which employs intravital microscopy to monitor leukocyte recruitment into the cremaster muscle. We found that, although R-FSL1, S-FSL1, Pam2CSK4, and Pam3CSK4 were all able to stimulate robust leukocyte recruitment in vivo, LTA remained functionally inert in this in vivo model. Therefore distinct TLR2 ligands elicit unique cellular responses, as evidenced by differences in the kinetic profiles of signaling and gene expression responses in vitro, as well as the physiologically relevant differences in the in vivo responses to these ligands.

  14. Peroxisome proliferator-activated receptor γ ligands suppress liver carcinogenesis induced by diethylnitrosamine in rats

    Institute of Scientific and Technical Information of China (English)

    Yan-Tong Guo; Xi-Sheng Leng; Tao Li; Jing-Ming Zhao; Xi-Hou Lin

    2004-01-01

    AIM: Peroxisome proliferator-activated receptor γ (PPARγ)is known to regulate growth arrest and terminal differentiation of adipocytes and is used clinically as a new class of antidiabetic drugs. Recently, several studies have reported that treatment of cancer cells with PPARγ ligands could induce cell differentiation and apoptosis, suggesting a potential application as chemopreventive agents against carcinogenesis. In the present study, 3 different kinds of PPARγ ligands were subjected to the experiments to confirm their suppressive effects on liver carcinogenesis.METHODS: Three PPARγ ligands, pioglitazone (Pio) (200 ppm),rosiglitazone (Rosi) (200 ppm), and troglitazone (Tro)(1 000 ppm) were investigated on the induction of the placental form of rat glutathione S-transferase (rGST P)positive foci, a precancerous lesion of the liver, and liver cancer formation using a diethylnitrosamine-induced liver cancer model in Wistar rats, and dose dependency of a PPARγ ligand was also examined.RESULTS: PPARγ ligands reduced the formation of rGST P-positive foci by diethylnitrosamine and induction of liver cancers was also markedly suppressed by a continuous feeding of Pio at 200 ppm.CONCLUSION: PPARγ ligands are potential chemopreventive agents for liver carcinogenesis.

  15. DNMT3A R882 Mutation with FLT3-ITD Positivity Is an Extremely Poor Prognostic Factor in Patients with Normal-Karyotype Acute Myeloid Leukemia after Allogeneic Hematopoietic Cell Transplantation.

    Science.gov (United States)

    Ahn, Jae-Sook; Kim, Hyeoung-Joon; Kim, Yeo-Kyeoung; Lee, Seun-Shin; Jung, Sung-Hoon; Yang, Deok-Hwan; Lee, Je-Jung; Kim, Nan Young; Choi, Seung Hyun; Jung, Chul Won; Jang, Jun-Ho; Kim, Hee Je; Moon, Joon Ho; Sohn, Sang Kyun; Won, Jong-Ho; Kim, Sung-Hyun; Kim, Dennis Dong Hwan

    2016-01-01

    The prognostic relevance of epigenetic modifying genes (DNMT3A, TET2, and IDH1/2) in patients with acute myeloid leukemia (AML) has been investigated extensively. However, the prognostic implications of these mutations after allogeneic hematopoietic cell transplantation (HCT) have not been evaluated comprehensively in patients with normal-karyotype (NK)-AML. A total of 115 patients who received allogeneic HCT for NK-AML were retrospectively evaluated for the FLT3-ITD, NPM1, CEBPA, DNMT3A, TET2, IDH1/2, WT1, NRAS, ASXL2, FAT1, DNAH11, and GATA2 mutations in diagnostic samples and analyzed for long-term outcomes after allogeneic HCT. The prevalence rates for the mutations were as follows: FLT3-ITD positivity (FLT3-ITD(pos)) (32.2%), NPM1 mutation (43.5%), CEBPA mutation (double) (24.6%), DNMT3A mutation (DNMT3A(mut)) (31.3%), DNMT3A R882(mut) (18.3%), TET2 mutation (8.7%), and IDH1/2 mutation (16.5%). The 5-year overall survival (OS) and event-free survival (EFS) rates were 57.3% and 58.1%, respectively. A multivariate analysis revealed that FLT3-ITD(pos) (hazard ratio, [HR], 2.23; P = .006) and DNMT3A R882(mut) (HR, 2.74; P = .002) were unfavorable prognostic factors for OS. In addition, both mutations were significant risk factors for EFS and relapse. People with DNMT3A R882(mut) accompanied by FLT3-ITD(pos) had worse OS and EFS, and higher relapse rates than those with the other mutations, which were confirmed in a propensity score 1:2 matching analysis. These results suggest that DNMT3A R882(mut), particularly when accompanied by FLT3-ITD(pos), is a significant prognostic factor for inferior transplantation survival outcome by increasing relapse risk, even after allogeneic HCT.

  16. Acute WT1-positive promyelocytic leukemia with hypogranular variant morphology, bcr-3 isoform of PML-RARα and Flt3-ITD mutation: a rare case report

    Directory of Open Access Journals (Sweden)

    Xi Zhang

    Full Text Available ABSTRACT CONTEXT: Acute promyelocytic leukemia (APL accounts for 8% to 10% of cases of acute myeloid leukemia (AML. Remission in cases of high-risk APL is still difficult to achieve, and relapses occur readily. CASE REPORT: Here, we describe a case of APL with high white blood cell counts in blood tests and hypogranular variant morphology in bone marrow, together with fms-like tyrosine kinase-3 with internal tandem duplication mutations (FLT3-ITD, and bcr-3 isoform of PML-RARα. Most importantly, we detected high level of Wilms’ tumor gene (WT1 in marrow blasts, through the reverse transcription polymerase chain reaction (RT-PCR. To date, no clear conclusions about an association between WT1 expression levels and APL have been reached. This patient successively received a combined treatment regimen consisting of hydroxycarbamide, arsenic trioxide and idarubicin plus cytarabine, which ultimately enabled complete remission. Unfortunately, he subsequently died of sudden massive hemoptysis because of pulmonary infection. CONCLUSION: Based on our findings and a review of the literature, abnormal functioning of WT1 may be a high-risk factor in cases of APL. Further studies aimed towards evaluating the impact of WT1 expression on the prognosis for APL patients are of interest.

  17. Ligand-induced conformational changes: Improved predictions of ligand binding conformations and affinities

    DEFF Research Database (Denmark)

    Frimurer, T.M.; Peters, Günther H.J.; Iversen, L.F.

    2003-01-01

    A computational docking strategy using multiple conformations of the target protein is discussed and evaluated. A series of low molecular weight, competitive, nonpeptide protein tyrosine phosphatase inhibitors are considered for which the x-ray crystallographic structures in complex with protein...... tyrosine phosphatase 1 B (PTP1B) are known. To obtain a quantitative measure of the impact of conformational changes induced by the inhibitors, these were docked to the active site region of various structures of PTP1B using the docking program FlexX. Firstly, the inhibitors were docked to a PTP1B crystal...... predicted binding energy and a correct docking mode. Thirdly, to improve the predictability of the docking procedure in the general case, where only a single target protein structure is known, we evaluate an approach which takes possible protein side-chain conformational changes into account. Here, side...

  18. Visualization of ligand-induced Gi-protein activation in chemotaxing cells.

    Science.gov (United States)

    Masuda, Kazuyuki; Kitakami, Jun-Ichi; Kozasa, Tohru; Kodama, Tatsuhiko; Ihara, Sigeo; Hamakubo, Takao

    2017-03-01

    Cell migration to chemoattractants is critically important in both normal physiology and the pathogenesis of many diseases. In GPCR-mediated chemotaxis, GPCRs transduce the gradient of an extracellular chemotactic ligand into intracellular responses via the activation of heterotrimeric G proteins. However, ligand-induced G-protein activation has not been directly imaged as yet in mammalian chemotaxing cells. We developed a Förster resonance energy transfer (FRET) probe, R10-Gi, by linking the Gi-protein α subunit to the regulator of G-protein signaling domain. The R10-Gi probe was coupled with a chemoattractant leukotriene B4 (LTB4) receptor 1 (BLT1) that induced the receptor to display a high-affinity ligand binding activity (Kd = 0.91 nM) in HEK293 cells. The R10-Gi probe exhibited an increased FRET signal in accord with the LTB4-dependent activation of Gi Furthermore, neutrophil-like differentiated human leukemia cell line 60 that expressed the intrinsic BLT1 displayed temporal Gi-protein activation in an area localized to the leading edge during chemotaxis in a shallow gradient of LTB4 These findings afford an opportunity to clarify the mechanisms underlying the subcellular regulation of Gi-protein activity, as well as GPCR-mediated ligand sensing, during chemotaxis in mammalian cells.-Masuda, K., Kitakami, J., Kozasa, T., Kodama, T., Ihara, S., Hamakubo, T. Visualization of ligand-induced Gi-protein activation in chemotaxing cells. © FASEB.

  19. Ligand-induced changes in estrogen receptor conformation as measured by site-directed spin labeling.

    Science.gov (United States)

    Hurth, Kyle M; Nilges, Mark J; Carlson, Kathryn E; Tamrazi, Anobel; Belford, R Linn; Katzenellenbogen, John A

    2004-02-24

    Site-directed spin labeling (SDSL), the site-specific incorporation of nitroxide spin-labels into a protein, has allowed us to investigate ligand-induced conformational changes in the ligand-binding domain of human estrogen receptor alpha (hERalpha-LBD). EPR (electron paramagnetic resonance) spectroscopy of the nitroxide probe attached to ER produces different spectra depending upon the identity of the bound ligand; these differences are indicative of changes in the type and degree of motional character of the spin-label induced by different ligand-induced conformations of labeled ER. Visual inspection of EPR spectra, construction of B versus C cross-correlation plots, and cross-comparison of spectral pairs using a relative squared difference (RSD) calculation allowed receptor-ligand complexes to be profiled according to their conformational character. Plotting B and C parameters allowed us to evaluate the liganded receptor according to the motional characteristics of the attached spin-label, and they were particularly illustrative for the receptor labeled at position 530, which had motion between the fast and intermediate regimes. RSD analysis allowed us to directly compare the similarity or difference between two different spectra, and these comparisons produced groupings that paralleled those seen in B versus C cross-correlation plots, again relating meaningfully with the pharmacological nature of the bound ligand. RSD analysis was also particularly useful for qualifying differences seen with the receptor labeled at position 417, which had motion between the intermediate and slow motional regimes. This work demonstrates that B and C formulas from EPR line shape theory are useful for qualitative analysis of spectra with differences subtler than those that are often analyzed by EPR spectroscopists. This work also provides evidence that the ER can exist in a range of conformations, with specific conformations resulting from preferential stabilization of ER by the

  20. Successful treatment of post-transplant relapsed acute myeloid leukemia with FLT3 internal tandem duplication using the combination of induction chemotherapy, donor lymphocyte infusion, sorafenib and azacitidine. Report of three cases.

    Science.gov (United States)

    Campregher, Paulo Vidal; Mattos, Vinicius Renan Pinto de; Salvino, Marco Aurélio; Santos, Fabio Pires de Souza; Hamerschlak, Nelson

    2017-07-24

    Acute myeloid leukemia is a hematopoietic stem cell neoplastic disease associated with high morbidity and mortality. The presence of FLT3 internal tandem duplication mutations leads to high rates of relapse and decreased overall survival. Patients with FLT3 internal tandem duplication are normally treated with hematopoietic stem cell transplantation in first complete remission. Nevertheless, the incidence of post-transplant relapse is considerable in this group of patients, and the management of this clinical condition is challenging. The report describes the outcomes of patients with FLT3 internal tandem duplication positive acute myeloid leukemia who relapsed after allogeneic hematopoietic stem cell transplantation and were treated with the combination of re-induction chemotherapy, donor lymphocyte infusion, sorafenib and azacitidine. Three cases are described and all patients achieved prolonged complete remission with the combined therapy. The combination of induction chemotherapy followed by donor lymphocyte infusion, and the maintenance with azacitidine and sorafenib can be effective approaches in the treatment of post-hematopoietic stem cell transplant and relapsed FLT3 internal tandem duplication positive acute myeloid leukemia patients. This strategy should be further explored in the context of clinical trials. RESUMO A leucemia mieloide aguda é uma doença neoplásica de células-tronco hematopoiéticas com alta morbimortalidade. A presença de mutações de duplicação em tandem de FLT3 leva a altas taxas de recorrência e a menor sobrevida global. Os pacientes com duplicação em tandem de FLT3 são normalmente tratados com transplante de células-tronco hematopoiéticas na primeira remissão completa. No entanto, a incidência de recidiva pós-transplante é considerável neste grupo de pacientes, e a conduta, nestes casos, é um desafio. O relato descreve os resultados do tratamento de pacientes com leucemia mieloide aguda positiva e duplicação em

  1. Cooperation between lateral ligand mobility and accessibility for receptor recognition in selectin-induced cell rolling

    NARCIS (Netherlands)

    Bakowsky, U; Schumacher, G; Gege, C; Schmidt, RR; Rothe, U; Bendas, G

    2002-01-01

    Selectin-induced leukocyte rolling along the endothelial surface is an essential step in the immune response. Several in vitro studies showed that this cell rolling is a highly regulated adhesion phenomenon, controlled by the kinetics and forces of selectin-ligand interactions. In the flow chamber s

  2. Ligand Modulation of the Epstein-Barr Virus-induced Seven-transmembrane Receptor EBI2

    DEFF Research Database (Denmark)

    Benned-Jensen, Tau; Smethurst, Christopher; Holst, Peter Johannes;

    2011-01-01

    The Epstein-Barr virus-induced receptor 2 (EBI2) is a constitutively active seven-transmembrane receptor, which was recently shown to orchestrate the positioning of B cells in the follicle. To date, no ligands, endogenously or synthetic, have been identified that modulate EBI2 activity. Here we...

  3. Prevention of carrageenan-induced pleurisy in mice by anti-CD30 ligand monoclonal antibody

    DEFF Research Database (Denmark)

    Di Paola, Rosanna; Di Marco, Roberto; Mazzon, Emanuela;

    2004-01-01

    CD30 ligand (CD30L) and its receptor CD30 are members of the tumor necrosis factor (TNF) and TNF receptor superfamilies that play a major role in inflammation and immune regulation. To gain insight into the in vivo role of CD30L/CD30 in inflammatory diseases, we have used carrageenan (CAR)-induce...

  4. Dendritic cells overexpressing Fas-ligand induce pulmonary vasculitis in mice

    NARCIS (Netherlands)

    Buonocore, S; Flamand, [No Value; Claessen, N; Heeringa, P; Goldman, M; Florquin, S

    2004-01-01

    Dendritic cells (DC) genetically engineered to express Fas (CD95) ligand (FasL-DC) have been proposed as immunotherapeutic tools to induce tolerance to allografts. However, we and others recently showed that FasL-DC elicit a vigorous inflammatory response involving granulocytes and can promote Th1-t

  5. Prognostic significance of FLT3 internal tandem duplication, nucleophosmin 1, and CEBPA gene mutations for acute myeloid leukemia patients with normal karyotype and younger than 60 years: a systematic review and meta-analysis.

    Science.gov (United States)

    Port, M; Böttcher, M; Thol, F; Ganser, A; Schlenk, R; Wasem, J; Neumann, A; Pouryamout, L

    2014-08-01

    Diagnosis and classification of acute myeloid leukemia (AML) are based on morphology and genetics. An increasing number of gene mutations have been found, and some are used for risk classification in AML patients with normal karyotype (cytogenetically normal (CN)-AML). In this systematic review and meta-analysis, we examined three frequent mutations in CN-AML: mutations of fms-related tyrosine kinase 3 (FLT3-ITD), mutated nucleophosmin (NPM1), and mutations of the CCAAT enhancer-binding protein alpha (CEBPA) gene. A systematic literature search of publications listed in the electronic databases (Embase, Pubmed, Healthstar, BIOSIS, ISI Web of Knowledge and Cochrane) from 2000 up to March 2012 was performed (Fig. 1). Nineteen studies were included and qualitatively analyzed. Two to four studies entered the quantitative meta-analysis incorporating 1,378 to 1,942 patients with CN-AML. Meta-analysis for overall survival (OS) and relapse-free survival (RFS) showed FLT3-ITD to predict an unfavorable prognosis, with hazard ratios (HR) of 1.86 and 1.75, respectively. In contrast, meta-analysis of the impact of NPM1 and CEBPA mutations on OS yielded an HR of 0.56 for each mutation, while analysis of impact on RFS produced HRs of 0.37 and 0.42, respectively. This systematic review and meta-analysis aimed to evaluate the prognostic value of mutations in the NPM1, CEBPA, and FLT3 genes. FLT3-ITD was associated with worse prognosis, whereas mutations in NPM1 and CEBPA genes were associated with a favorable prognosis.

  6. Tumor cells prevent mouse dendritic cell maturation induced by TLR ligands.

    Science.gov (United States)

    Idoyaga, Juliana; Moreno, José; Bonifaz, Laura

    2007-08-01

    Tumor cells can evade the immune system through several mechanisms, one of which is to block DC maturation. It has been suggested that signaling via Toll-like receptors (TLR) may be involved in the induction of prophylactic anti-cancer immunity and in the treatment of established tumors. In the present study we found that high numbers of tumor cells interfere with BMDC activation induced by the TLR ligands LPS and poly IC. Tumor cells blocked TLR3- and TLR4-mediated induction of MHCII and the co-stimulatory molecules CD40 and CD86, as well as the cytokines IL-12, TNF-alpha and IL-6. Importantly, tumor cells induced inhibitory molecules (B7-DC, B7-H1 and CD80) on spleen DC in vivo and on BMDC, even in the presence of TLR ligands. Moreover, after a long exposure with tumor cells, purified BMDC were unable to respond to a second challenge with TLR ligands. The failure of tumor exposed-BMDC to express co-stimulatory molecules and cytokines in the presence of TLR ligands has implications for the future development of DC-based cancer immune therapies using TLR ligands as adjuvants for the activation of DC.

  7. Binding-Induced Fluorescence of Serotonin Transporter Ligands

    DEFF Research Database (Denmark)

    Wilson, James; Ladefoged, Lucy Kate; Babinchak, Michael

    2014-01-01

    The binding-induced fluorescence of 4-(4-(dimethylamino)-phenyl)-1-methylpyridinium (APP(+)) and two new serotonin transporter (SERT)-binding fluorescent analogues, 1-butyl-4-[4-(1-dimethylamino)phenyl]-pyridinium bromide (BPP(+)) and 1-methyl-4-[4-(1-piperidinyl)phenyl]-pyridinium (PPP(+)), has...

  8. Species-specific kinetics and zonation of hepatic DNA synthesis induced by ligands of PPARalpha.

    Science.gov (United States)

    Al Kholaifi, Abdullah; Amer, Abeer; Jeffery, Brett; Gray, Tim J B; Roberts, Ruth A; Bell, David R

    2008-07-01

    Peroxisome proliferator-activated receptor alpha (PPARalpha) ligands evoke a profound mitogenic response in rodent liver, and the aim of this study was to characterize the kinetics of induction of DNA synthesis. The CAR ligand, 1,4-bis[2-(3,5-dichoropyridyloxy)]benzene, caused induction of hepatocyte DNA synthesis within 48 h in 129S4/SvJae mice, but the potent PPARalpha ligand, ciprofibrate, induced hepatocyte DNA synthesis only after 3 or 4 days dosing; higher or lower doses did not hasten the DNA synthesis response. This contrasted with the rapid induction (24 h) reported by Styles et al., 1988, Carcinogenesis 9, 1647-1655. C57BL/6 and DBA/2J mice showed significant induction of DNA synthesis after 4, but not 2, days ciprofibrate treatment. Alderley Park and 129S4/SvJae mice dosed with methylclofenapate induced hepatocyte DNA synthesis at 4, but not 2, days after dosing and proved that inconsistency with prior work was not due to a difference in mouse strain or PPARalpha ligand. Ciprofibrate-induced liver DNA synthesis and growth was absent in PPARalpha-null mice and are PPARalpha dependent. In the Fisher344 rat, hepatocyte DNA synthesis was induced at 24 h after dosing, with a second peak at 48 h. Lobular localization of hepatocyte DNA synthesis showed preferential periportal induction of DNA synthesis in rat but panlobular zonation of hepatocyte DNA synthesis in mouse. These results characterize a markedly later hepatic induction of panlobular DNA synthesis by PPARalpha ligands in mouse, compared to rapid induction of periportal DNA synthesis in rat.

  9. FLT3-ITD and MLL-PTD influence the expression of MDR-1, MRP-1, and BCRP mRNA but not LRP mRNA assessed with RQ-PCR method in adult acute myeloid leukemia.

    Science.gov (United States)

    Nasilowska-Adamska, Barbara; Solarska, Iwona; Paluszewska, Monika; Malinowska, Iwona; Jedrzejczak, Wieslaw W; Warzocha, Krzysztof

    2014-04-01

    Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) and mixed-lineage leukemia gene-partial tandem duplication (MLL-PTD) are aberrations associated with leukemia which indicate unsatisfactory prognosis. Downstream regulatory targets of FLT3-ITD and MLL-PTD are not well defined. We have analyzed the expression of MDR-1, multidrug resistant protein-1 (MRP-1), breast cancer resistance protein (BCRP), and lung resistance protein (LRP) messenger RNA (mRNA) in relation to the mutational status of FLT3-ITD and MLL-PTD in 185 acute myeloid leukemia (AML) adult patients. The real-time quantitative polymerase chain reaction method was performed to assess the expression of the MDR-1, MRP-1, BCRP, and LRP mRNA, and the results were presented as coefficients calculated using an intermediate method according to Pfaffl's rule. Significantly higher expressions of MDR-1 mRNA were found in patients who did not harbor FLT3-ITD (0.20 vs. 0.05; p = 0.0001) and MRP-1 mRNA in patients with this mutation (0.96 vs. 0.70; p = 0.002) and of BCRP mRNA in patients with MLL-PTD (0.61 vs. 0.38; p = 0.03). In univariate analysis, the high expression of MDR-1 mRNA (≥0.1317) negatively influenced the outcome of induction therapy (p = 0.05), whereas the high expression of BCRP mRNA (≥1.1487) was associated with a high relapse rate (RR) (p = 0.013). We found that the high expression of MDR-1 (≥0.1317), MRP-1 (≥0.8409), and BCRP mRNA (≥1.1487) significantly influenced disease-free survival (DFS; p = 0.059, 0.032, and 0.009, respectively) and overall survival (0.048, 0.014, and 0.059, respectively). Moreover, a high expression of BCRP mRNA (≥1.1487) proved to be an independent prognostic factor for RR (p = 0.01) and DFS (p = 0.002) in multivariate analysis. The significant correlation between the expression of MDR-1, MRP-1, and BCRP mRNA and FLT3-ITD or MLL-PTD in AML patients requires further investigation.

  10. Non-Ligand-Induced Dimerization is Sufficient to Initiate the Signalling and Endocytosis of EGF Receptor

    Directory of Open Access Journals (Sweden)

    George Kourouniotis

    2016-07-01

    Full Text Available The binding of epidermal growth factor (EGF to EGF receptor (EGFR stimulates cell mitogenesis and survival through various signalling cascades. EGF also stimulates rapid EGFR endocytosis and its eventual degradation in lysosomes. The immediate events induced by ligand binding include receptor dimerization, activation of intrinsic tyrosine kinase and autophosphorylation. However, in spite of intensified efforts, the results regarding the roles of these events in EGFR signalling and internalization is still very controversial. In this study, we constructed a chimeric EGFR by replacing its extracellular domain with leucine zipper (LZ and tagged a green fluorescent protein (GFP at its C-terminus. We showed that the chimeric LZ-EGFR-GFP was constitutively dimerized. The LZ-EGFR-GFP dimer autophosphorylated each of its five well-defined C-terminal tyrosine residues as the ligand-induced EGFR dimer does. Phosphorylated LZ-EGFR-GFP was localized to both the plasma membrane and endosomes, suggesting it is capable of endocytosis. We also showed that LZ-EGFR-GFP activated major signalling proteins including Src homology collagen-like (Shc, extracellular signal-regulated kinase (ERK and Akt. Moreover, LZ-EGFR-GFP was able to stimulate cell proliferation. These results indicate that non-ligand induced dimerization is sufficient to activate EGFR and initiate cell signalling and EGFR endocytosis. We conclude that receptor dimerization is a critical event in EGF-induced cell signalling and EGFR endocytosis.

  11. Non-Ligand-Induced Dimerization is Sufficient to Initiate the Signalling and Endocytosis of EGF Receptor

    OpenAIRE

    Kourouniotis, George; Wang, Yi; Pennock, Steven; Chen, Xinmei; Wang, Zhixiang

    2016-01-01

    The binding of epidermal growth factor (EGF) to EGF receptor (EGFR) stimulates cell mitogenesis and survival through various signalling cascades. EGF also stimulates rapid EGFR endocytosis and its eventual degradation in lysosomes. The immediate events induced by ligand binding include receptor dimerization, activation of intrinsic tyrosine kinase and autophosphorylation. However, in spite of intensified efforts, the results regarding the roles of these events in EGFR signalling and internali...

  12. Glucocorticoid-induced tumour necrosis factor receptor (GITR) and its ligand (GITRL) in atopic dermatitis

    DEFF Research Database (Denmark)

    Baumgartner-Nielsen, Jane; Vestergaard, Christian; Thestrup-Pedersen, K.

    2006-01-01

    The glucocorticoid-induced tumour necrosis factor receptor-related gene (GITR) is expressed on regulatory T-cells (Treg), which are CD4+CD25+ lymphocytes. Binding of the GITR-ligand (GITRL) leads to downregulation of the regulatory function of Tregs. Patients suffering from a defect in their Treg......-cells are localized in the vicinity of GITRL-expressing cells in atopic dermatitis skin, the GITR/GITRL interaction may serve to perpetuate the inflammation locally....

  13. Ligand induced circular dichroism and circularly polarized luminescence in CdSe quantum dots.

    Science.gov (United States)

    Tohgha, Urice; Deol, Kirandeep K; Porter, Ashlin G; Bartko, Samuel G; Choi, Jung Kyu; Leonard, Brian M; Varga, Krisztina; Kubelka, Jan; Muller, Gilles; Balaz, Milan

    2013-12-23

    Chiral thiol capping ligands L- and D-cysteines induced modular chiroptical properties in achiral cadmium selenide quantum dots (CdSe QDs). Cys-CdSe prepared from achiral oleic acid capped CdSe by postsynthetic ligand exchange displayed size-dependent electronic circular dichroism (CD) and circularly polarized luminescence (CPL). Opposite CPL signals were measured for the CdSe QDs capped with D- and L-cysteine. The CD profile and CD anisotropy varied with size of CdSe nanocrystals with largest anisotropy observed for CdSe nanoparticles of 4.4 nm. Magic angle spinning solid state NMR (MAS ssNMR) experiments suggested bidentate interaction between cysteine and the surface of CdSe. Time Dependent Density Functional Theory (TDDFT) calculations verified that attachment of L- and D-cysteine to the surface of model (CdSe)13 nanoclusters induces measurable opposite CD signals for the exitonic band of the nanocluster. The origin of the induced chirality is consistent with the hybridization of highest occupied CdSe molecular orbitals with those of the chiral ligand.

  14. Ligand Induced Circular Dichroism and Circularly Polarized Luminescence in CdSe Quantum Dots

    Science.gov (United States)

    Tohgha, Urice; Deol, Kirandeep K.; Porter, Ashlin G.; Bartko, Samuel G.; Choi, Jung Kyu; Leonard, Brian M.; Varga, Krisztina; Kubelka, Jan; Muller, Gilles; Balaz, Milan

    2014-01-01

    Chiral thiol capping ligands L- and D-cysteines induced modular chiroptical properties in achiral cadmium selenide quantum dots (CdSe QDs). Cys-CdSe prepared from achiral oleic acid capped CdSe by post-synthetic ligand exchange displayed size-dependent electronic circular dichroism (CD) and circularly polarized luminescence (CPL). Opposite CPL signals were measured for the CdSe QDs capped with D- and L-cysteine. The CD profile and CD anisotropy varied with size of CdSe nanocrystals with largest anisotropy observed for CdSe nanoparticles of 4.4 nm. Magic angle spinning solid state NMR (MAS ssNMR) experiments suggested bidentate interaction between cysteine and the surface of CdSe. Density functional theory (DFT) calculations verified that attachment of L- and D-cysteine to the surface of model (CdSe)13 nanoclusters induces measurable opposite CD signals for the exitonic band of the nanocluster. The chirality was induced by the hybridization of highest occupied CdSe molecular orbitals with those of the chiral ligand. PMID:24200288

  15. Phase 1/2 study of pacritinib, a next generation JAK2/FLT3 inhibitor, in myelofibrosis or other myeloid malignancies

    Directory of Open Access Journals (Sweden)

    Srdan Verstovsek

    2016-12-01

    Full Text Available Abstract Background Pacritinib (SB1518 is a highly selective kinase inhibitor with specificity for JAK2, FLT3, IRAK1, and CFS1R. This multicenter phase 1/2 study evaluated the maximum tolerated dose (MTD, safety, and clinical activity of pacritinib in patients with myelofibrosis (MF and other advanced myeloid malignancies. Methods In the phase 1 dose-escalation part of the study, 43 adults with advanced myeloid malignancies received pacritinib 100 to 600 mg once daily (QD. In the phase 2 part of the study, 31 adults with refractory or intermediate- or high-risk newly diagnosed MF and any degree of cytopenia received pacritinib 400 mg QD. The primary endpoint is a ≥35% reduction in spleen volume at week 24 as determined by magnetic resonance imaging. Results Five patients (11.6% experienced a dose-limiting toxicity during cycle 1 of phase 1. The clinical benefit rate was 86.0% (13 patients achieving clinical improvement and 24 patients having stable disease. The MTD was established at 500 mg QD, and the recommended phase 2 dose was 400 mg QD. In phase 2, the primary endpoint was achieved by 23.5% of evaluable patients (4/17, with 47.4% (9/19 achieving a ≥50% spleen length reduction at week 24 as measured by physical examination. At week 24, 38.9% of evaluable patients (7/18 achieved a ≥50% decrease in MF Quality of Life and Symptom Assessment total score. Gastrointestinal toxicities were the most common adverse events and were predominantly grade 1/2 in severity. Grade 3/4 anemia was reported in 5/31 patients and grade 3/4 thrombocytopenia was reported in 3/31 patients. The most frequent AEs considered to be treatment related were diarrhea (28/31, nausea (15/31, vomiting (9/31, and fatigue (4/31. Grade 3 treatment-related AEs were reported in seven patients (22.6%, four of whom had diarrhea. No grade 4/5 treatment-related AEs were reported. No leukopenia, neutropenia, or lymphopenia were reported. Conclusions Pacritinib was well

  16. Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses

    Energy Technology Data Exchange (ETDEWEB)

    Fukuyama, Yoshiko; Tokuhara, Daisuke [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Division of Mucosal Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639 (Japan); Sekine, Shinichi [Department of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Osaka 565-0871 (Japan); Kataoka, Kosuke [Department of Preventive Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Markham, Jonathan D.; Irwin, Allyson R.; Moon, Grace H.; Tokuhara, Yuka; Fujihashi, Keiko [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Davydova, Julia; Yamamoto, Masato [Department of Surgery, University of Minnesota, Minneapolis, MN 55455 (United States); Gilbert, Rebekah S. [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Fujihashi, Kohtaro, E-mail: kohtarof@uab.edu [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States)

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer Nasal Ad-FL effectively up-regulates APC function by CD11c{sup +} DCs in mucosal tissues. Black-Right-Pointing-Pointer Nasal Ad-FL induces Notch ligand (L)-expressing CD11c{sup +} DCs. Black-Right-Pointing-Pointer Notch L-expressing DCs support the induction of Th1- and Th2-type cytokine responses. -- Abstract: Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c{sup +} dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c{sup +} DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c{sup +} DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c{sup +} DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4{sup +} T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-{gamma}, IL-2 and IL-4 producing CD4{sup +} T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch-Notch-L pathway. These results show that Ad-FL induces CD11c{sup +} DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.

  17. Plasminogen activator inhibitor-1 polymers, induced by inactivating amphipathic organochemical ligands

    DEFF Research Database (Denmark)

    Pedersen, Katrine E; Einholm, Anja P; Christensen, Anni;

    2003-01-01

    -induced polymerization was observed only with PAI-1 and heparin cofactor II, which were also able to copolymerize. On the basis of these results, we suggest that the binding of ligands in a specific region of PAI-1 leads to so-called loop-sheet polymerization, in which the reactive centre loop of one molecule binds....... As compared with native PAI-1, the polymers exhibited an increased resistance to temperature-induced unfolding. Polymerization was associated with specific changes in patterns of digestion with non-target proteases. During incubation with urokinase-type plasminogen activator, the polymers were slowly...

  18. Enhancement of germ cell apoptosis induced by ethanol in transgenic mice overexpressing Fas Ligand

    Institute of Scientific and Technical Information of China (English)

    HENG CHUAN XIA; FENG LI; ZHEN LI; ZU CHUAN ZHANG

    2003-01-01

    It was suggested that chronic ethanol exposure could result in testicular germ cell apoptosis, but the mechanism is still unclear. In the present study, we use a model of transgenic mice ubiquitously overexpressing human FasL to investigate whether Fas ligand plays a role in ethanol-induced testicular germ cell apoptosis. Both wild-type (WT)mice and transgenic (TG) mice were treated with acute ethanol (20% v/v) by introperitoneal injection for five times.After ethanol injection, WT mice displayed up-regulation of Fas ligand in the testes, which was shown by FITCconjugated flow cytometry and western blotting. Moreover, TG mice exhibited significantly more apoptotic germ cells than WT mice did after ethanol injection, which was demonstrated by DNA fragmentation, PI staining flow cytometry and TUNEL staining. In addition, histopathological examination revealed that degenerative changes of epithelial component of the tubules occurred in FasL overexpressing transgenic mice while testicular morphology was normal in wild-type mice after acute ethanol exposure, suggesting FasL expression determines the sensitivity of testes to ethanol in mice. In summary, we provide the direct evidences that Fas ligand mediates the apoptosis of testicular germ cells induced by acute ethanol using FasL transgenic mice.

  19. A new feature of Mpl receptor: ligand-induced transforming activity in FRE rat fibroblasts.

    Science.gov (United States)

    Challier, C; Cocault, L; Flon, M; Pauchard, M; Porteu, F; Gisselbrecht, S; Souyri, M

    2000-04-13

    Mpl is the receptor for thrombopoietin, the primary regulator of platelet production by megakaryocytes. Upon stimulation by its ligand, Mpl receptor induces proliferation and differentiation of hematopoietic cell lines of various origins. In this paper, we show that Mpl is also able to transform FRE rat fibroblasts in the presence of MGDF (pegylated Megakaryocyte Growth and Development Factor), a modified form of its ligand. We also demonstrate that upon MGDF stimulation Mpl receptor activates the classical transduction pathways described for hematopoietic cell lines in FRE cells. Introduction of Mpl deletion mutants in FRE cells allowed us to demonstrate that the C-terminal region of the Mpl intracytoplasmic domain, which is involved in hematopoietic differentiation, is necessary for the transformation process. Within that region, site-directed mutagenesis showed that the Y112 residue, which is required for Shc phosphorylation, is essential for rat fibroblast transformation by Mpl/MGDF, suggesting the involvement of Shc in Mpl-mediated transformation. Interestingly, we showed that transformation correlated with strong and sustained MAPK activation. Neither Jak2, Stat3 nor Stat5 phosphorylation was sufficient to induce the transformation process. Taken altogether, our results suggest the oncogenicity of Mpl in fibroblastic cells in the presence of its ligand.

  20. Interacción de la proteína-tirosina fosfatasa SHP-1 y la proteína-tirosina kinasa FLT3 constitutivamente activada en las enfermedades malignas mieloides: Un nuevo factor pronóstico.

    OpenAIRE

    Mena Durán, Armando V.

    2008-01-01

    La búsqueda de factores pronósticos que permitan entender la heterogeneidad en laevolución de los pacientes diagnosticados de neoplasias mieloides ha dado paso a ladenominada "terapia adaptada al riesgo". Un buen ejemplo de ello son las mutacionesque afectan al dominio transmembranoso (ITD) y el dominio tirosina cinasa (D835) delreceptor de superficie celular de las células hematopoyéticas fms-like 3 (FLT3) queconstituye un conocido factor pronóstico en las leucemias aguda mieloblásticas (LMA...

  1. Interacción de la proteína-tirosina fosfatasa SHP-1 y la proteína-tirosina kinasa FLT3 constitutivamente activada en las enfermedades malignas mieloides: Un nuevo factor pronóstico.

    OpenAIRE

    Mena Durán, Armando V.

    2008-01-01

    RESUMEN La búsqueda de factores pronósticos que permitan entender la heterogeneidad en la evolución de los pacientes diagnosticados de neoplasias mieloides ha dado paso a la denominada terapia adaptada al riesgo. Un buen ejemplo de ello son las mutaciones que afectan al dominio transmembranoso (ITD) y el dominio tirosina cinasa (D835) del receptor de superficie celular de las células hematopoyéticas fms-like 3 (FLT3) que constituye un conocido factor pronóstico en las leucem...

  2. Interacción de la proteína-tirosina fosfatasa SHP-1 y la proteína-tirosina kinasa FLT3 constitutivamente activada en las enfermedades malignas mieloides: Un nuevo factor pronóstico.

    OpenAIRE

    Mena Durán, Armando V.

    2008-01-01

    RESUMEN La búsqueda de factores pronósticos que permitan entender la heterogeneidad en la evolución de los pacientes diagnosticados de neoplasias mieloides ha dado paso a la denominada terapia adaptada al riesgo. Un buen ejemplo de ello son las mutaciones que afectan al dominio transmembranoso (ITD) y el dominio tirosina cinasa (D835) del receptor de superficie celular de las células hematopoyéticas fms-like 3 (FLT3) que constituye un conocido factor pronóstico en las leucem...

  3. Regulation of endogenous human gene expression by ligand-inducible TALE transcription factors.

    Science.gov (United States)

    Mercer, Andrew C; Gaj, Thomas; Sirk, Shannon J; Lamb, Brian M; Barbas, Carlos F

    2014-10-17

    The construction of increasingly sophisticated synthetic biological circuits is dependent on the development of extensible tools capable of providing specific control of gene expression in eukaryotic cells. Here, we describe a new class of synthetic transcription factors that activate gene expression in response to extracellular chemical stimuli. These inducible activators consist of customizable transcription activator-like effector (TALE) proteins combined with steroid hormone receptor ligand-binding domains. We demonstrate that these ligand-responsive TALE transcription factors allow for tunable and conditional control of gene activation and can be used to regulate the expression of endogenous genes in human cells. Since TALEs can be designed to recognize any contiguous DNA sequence, the conditional gene regulatory system described herein will enable the design of advanced synthetic gene networks.

  4. The Role of TNF Related Apoptosis-Inducing Ligand in Neurodegenerative Diseases

    Institute of Scientific and Technical Information of China (English)

    Y.Huang; N.Erdmann; H.Peng; Y.Zhao

    2005-01-01

    A hallmark of all forms of neurodegenerative diseases is impairment of neuronal functions, and in many cases neuronal cell death. Although the etiology of neurodegenerative diseases may be distinct, different diseases display a similar pathogenesis, for example abnormal immunity within the central nervous system (CNS), activation of macrophage/microglia and the involvement of proinflammatory cytokines. Recent studies show that neurons in a neurodegenerative state undergo a highly regulated programmed cell death, also called apoptosis. TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF family, has been shown to be involved in apoptosis during many diseases. As one member of a death ligand family, TRAIL was originally thought to target only tumor cells and was not present in CNS. However, recent data showed that TRAIL was unregulated in HIV-l-infected and immune-activated macrophages, a major disease inducing cell during HIV-l-associated dementia (HAD). TRAIL is also induced on neuron by [$-amyloid protein, an important pathogen for Alzheimer's disease. In this review, we summarize the possible common aspects that TRAIL involved those neurodegenerative diseases, TRAIL induced apoptosis signaling in the CNS cells, and specific role of TRAIL in individual diseases. Cellular & MolecularImmunology. 2005;2(2):113-122.

  5. The Role of TNF Related Apoptosis-Inducing Ligand in Neurodegenerative Diseases

    Institute of Scientific and Technical Information of China (English)

    Y.Huang; N.Erdmann; H.Peng; Y.Zhao; Jialin Zheng

    2005-01-01

    A hallmark of all forms of neurodegenerative diseases is impairment of neuronal functions, and in many cases neuronal cell death. Although the etiology of neurodegenerative diseases may be distinct, different diseases display a similar pathogenesis, for example abnormal immunity within the central nervous system (CNS), activation of macrophage/microglia and the involvement of proinflammatory cytokines. Recent studies show that neurons in a neurodegenerative state undergo a highly regulated programmed cell death, also called apoptosis. TNF-related apoptosis-inducing ligand (TRAIL), a member of the TNF family, has been shown to be involved in apoptosis during many diseases. As one member of a death ligand family, TRAIL was originally thought to target only tumor cells and was not present in CNS. However, recent data showed that TRAIL was unregulated in HIV-1-infected and immune-activated macrophages, a major disease inducing cell during HIV-1-associated dementia (HAD). TRAIL is also induced on neuron by β-amyloid protein, an important pathogen for Alzheimer's disease. In this review, we summarize the possible common aspects that TRAIL involved those neurodegenerative diseases, TRAIL induced apoptosis signaling in the CNS cells, and specific role of TRAIL in individual diseases. Cellular & Molecular Immunology. 2005;2(2):113-122.

  6. Prevention of carrageenan-induced pleurisy in mice by anti-CD30 ligand monoclonal antibody

    DEFF Research Database (Denmark)

    Di Paola, Rosanna; Di Marco, Roberto; Mazzon, Emanuela

    2004-01-01

    CD30 ligand (CD30L) and its receptor CD30 are members of the tumor necrosis factor (TNF) and TNF receptor superfamilies that play a major role in inflammation and immune regulation. To gain insight into the in vivo role of CD30L/CD30 in inflammatory diseases, we have used carrageenan (CAR)-induce......-induced pleurisy. These data suggest involvement of CD30-mediated signals in acute immunoinflammatory pathways induced by CAR.......CD30 ligand (CD30L) and its receptor CD30 are members of the tumor necrosis factor (TNF) and TNF receptor superfamilies that play a major role in inflammation and immune regulation. To gain insight into the in vivo role of CD30L/CD30 in inflammatory diseases, we have used carrageenan (CAR......)-induced pleurisy in mice, a preclinical model of airway inflammation where type 1 proinflammatory cytokines such as interleukin (IL)-1 and TNF-alpha play a key pathogenic role. The data show that prophylactic treatment with anti-CD30L mAb markedly reduces both laboratory and histological signs of CAR...

  7. Roscovitine sensitizes leukemia and lymphoma cells to tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis.

    Science.gov (United States)

    Molinsky, Jan; Klanova, Magdalena; Koc, Michal; Beranova, Lenka; Andera, Ladislav; Ludvikova, Zdenka; Bohmova, Martina; Gasova, Zdenka; Strnad, Miroslav; Ivanek, Robert; Trneny, Marek; Necas, Emanuel; Zivny, Jan; Klener, Pavel

    2013-02-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand with selective antitumor activity. However, many primary tumors are TRAIL resistant. Previous studies reported that roscovitine, a cyclin-dependent kinase inhibitor, sensitized various solid cancer cells to TRAIL. We show that roscovitine and TRAIL demonstrate synergistic cytotoxicity in hematologic malignant cell lines and primary cells. Pretreatment of TRAIL-resistant leukemia cells with roscovitine induced enhanced cleavage of death-inducing signaling complex-bound proximal caspases after exposure to TRAIL. We observed increased levels of both pro- and antiapoptotic BCL-2 proteins at the mitochondria following exposure to roscovitine. These results suggest that roscovitine induces priming of cancer cells for death by binding antiapoptotic BCL-2 proteins to proapoptotic BH3-only proteins at the mitochondria, thereby decreasing the threshold for diverse proapoptotic stimuli. We propose that the mitochondrial priming and enhanced processing of apical caspases represent major molecular mechanisms of roscovitine-induced sensitization to TRAIL in leukemia/lymphoma cells.

  8. Local and global ligand-induced changes in the structure of the GABA(A) receptor.

    Science.gov (United States)

    Muroi, Yukiko; Czajkowski, Cynthia; Jackson, Meyer B

    2006-06-13

    Ligand-gated channels mediate synaptic transmission through conformational transitions triggered by the binding of neurotransmitters. These transitions are well-defined in terms of ion conductance, but their structural basis is poorly understood. To probe these changes in structure, GABA(A) receptors were expressed in Xenopus oocytes and labeled at selected sites with environment-sensitive fluorophores. With labels at two different residues in the alpha1 subunit in loop E of the GABA-binding pocket, GABA elicited fluorescence changes opposite in sign. This pattern of fluorescence changes is consistent with a closure of the GABA-binding cavity at the subunit interface. The competitive antagonist SR-95531 inverted this pattern of fluorescence change, but the noncompetitive antagonist picrotoxin failed to elicit optical signals. In response to GABA (but not SR-95531), labels at the homologous residues in the beta2 subunit showed the same pattern of fluorescence change as the alpha1-subunit labels, indicating a global transition with comparable movements in homologous regions of different subunits. Incorporation of the gamma2 subunit altered the fluorescence changes of alpha1-subunit labels and eliminated them in beta2-subunit labels. Thus, the ligand-induced structural changes in the GABA(A) receptor can extend over considerable distances or remain highly localized, depending upon subunit composition and ligand.

  9. RHPS4 G-quadruplex ligand induces anti-proliferative effects in brain tumor cells.

    Science.gov (United States)

    Lagah, Sunil; Tan, I-Li; Radhakrishnan, Priya; Hirst, Robert A; Ward, Jennifer H; O'Callaghan, Chris; Smith, Stuart J; Stevens, Malcolm F G; Grundy, Richard G; Rahman, Ruman

    2014-01-01

    Telomeric 3' overhangs can fold into a four-stranded DNA structure termed G-quadruplex (G4), a formation which inhibits telomerase. As telomerase activation is crucial for telomere maintenance in most cancer cells, several classes of G4 ligands have been designed to directly disrupt telomeric structure. We exposed brain tumor cells to the G4 ligand 3,11-difluoro-6,8,13-trimethyl-8H-quino[4,3,2-kl]acridinium methosulfate (RHPS4) and investigated proliferation, cell cycle dynamics, telomere length, telomerase activity and activated c-Myc levels. Although all cell lines tested were sensitive to RHPS4, PFSK-1 central nervous system primitive neuroectodermal cells, DAOY medulloblastoma cells and U87 glioblastoma cells exhibited up to 30-fold increased sensitivity compared to KNS42 glioblastoma, C6 glioma and Res196 ependymoma cells. An increased proportion of S-phase cells were observed in medulloblastoma and high grade glioma cells whilst CNS PNET cells showed an increased proportion of G1-phase cells. RHPS4-induced phenotypes were concomitant with telomerase inhibition, manifested in a telomere length-independent manner and not associated with activated c-Myc levels. However, anti-proliferative effects were also observed in normal neural/endothelial cells in vitro and ex vivo. This study warrants in vivo validation of RHPS4 and alternative G4 ligands as potential anti-cancer agents for brain tumors but highlights the consideration of dose-limiting tissue toxicities.

  10. PPARγ ligand ciglitazone inhibits TNFα-induced ICAM-1 in human airway smooth muscle cells

    Directory of Open Access Journals (Sweden)

    Chien-Da Huang

    2014-08-01

    Full Text Available Background: Modification of human airway smooth muscle (ASM function by proinflammatory cytokines has been regarded as a potential mechanism underlying bronchial hyperresponsiveness in asthma. Human ASM cells express intercellular adhesion molecule (ICAM-1 in response to cytokines. Synthetic ligands for peroxisome proliferator-activated receptor (PPARγ reportedly possess anti-inflammatory and immunomodulatory properties. In this study, we examined whether ciglitazone, a synthetic PPARγ ligand, can modulate the basal and tumor necrosis factor (TNFα-induced ICAM1 gene expression in human ASM cells. Methods: Human ASM cells were treated with TNFα. ICAM-1 expression was assessed by flow cytometry and reverse transcriptase-polymerase chain reaction (RT-PCR analysis. PPARγ activity was inhibited by target-specific small interfering (si RNA targeting PPARγ and GW9662, a PPARγ antagonist. Activity of nuclear factor (NF-κB was assessed by using immunoblot analysis, immune-confocal images, and electrophoretic mobility shift assay (EMSA. Results: By flow cytometry, ciglitazone alone had no effect on ICAM-1 expression in ASM cells, but inhibited ICAM-1 expression in response to TNFα (10 ng/ml in a dose-dependent manner (1-10 μM. It also inhibited TNFα-induced ICAM1 gene expression by RT-PCR analysis. Knockdown of PPARγ gene by target-specific siRNA targeting PPARγ enhanced ICAM-1 expression and the inhibitory effect of ciglitazone on TNFα-induced ICAM-1 expression was reversed by PPARγ siRNA and GW9662. SN-50 (10 μg/ml, an inhibitor for nuclear translocation of NF-κB, inhibited TNFα-induced ICAM-1 expression. Ciglitazone did not prevent TNFα-induced degradation of the cytosolic inhibitor of NF-κB (IκB, but inhibited the nuclear translocation of p65 induced by TNFα and suppressed the NF-κB/DNA binding activity. Conclusion: These findings suggest that ciglitazone inhibits TNFα-induced ICAM1 gene expression in human ASM cells through

  11. Combined mutations of ASXL1, CBL, FLT3, IDH1, IDH2, JAK2, KRAS, NPM1, NRAS, RUNX1, TET2 and WT1 genes in myelodysplastic syndromes and acute myeloid leukemias

    Directory of Open Access Journals (Sweden)

    Vey Norbert

    2010-08-01

    Full Text Available Abstract Background Gene mutation is an important mechanism of myeloid leukemogenesis. However, the number and combination of gene mutated in myeloid malignancies is still a matter of investigation. Methods We searched for mutations in the ASXL1, CBL, FLT3, IDH1, IDH2, JAK2, KRAS, NPM1, NRAS, RUNX1, TET2 and WT1 genes in 65 myelodysplastic syndromes (MDSs and 64 acute myeloid leukemias (AMLs without balanced translocation or complex karyotype. Results Mutations in ASXL1 and CBL were frequent in refractory anemia with excess of blasts. Mutations in TET2 occurred with similar frequency in MDSs and AMLs and associated equally with either ASXL1 or NPM1 mutations. Mutations of RUNX1 were mutually exclusive with TET2 and combined with ASXL1 but not with NPM1. Mutations in FLT3 (mutation and internal tandem duplication, IDH1, IDH2, NPM1 and WT1 occurred primarily in AMLs. Conclusion Only 14% MDSs but half AMLs had at least two mutations in the genes studied. Based on the observed combinations and exclusions we classified the 12 genes into four classes and propose a highly speculative model that at least a mutation in one of each class is necessary for developing AML with simple or normal karyotype.

  12. Enzyme-free and sensitive electrochemical determination of the FLT3 gene based on a dual signal amplified strategy: Controlled nanomaterial multilayers and a target-catalyzed hairpin assembly.

    Science.gov (United States)

    Sun, Yingying; Ren, Qunxiang; Liu, Bo; Qin, Yan; Zhao, Shuang

    2016-04-15

    An isothermal, enzyme-free and sensitive electrochemical DNA sensor was developed for the detection of the FLT3 gene in acute myeloid leukemia (AML). First, aminated multi-walled carbon nanotubes (AMWNTs) and gold nanoparticles (AuNPs) were alternately self-assembled on a gold electrode using a layer-by-layer strategy. Then, the hairpin DNA probe 1 (H1), with a thiol group at the 3' end and a ferrocenyl moiety (Fc) at the 5' end, was immobilized on the AMWNTs/AuNPs multilayer films through Au-S bonding. When the target DNA (TD) appeared, it hybridized with and opened the hairpin structure of H1, and Fc was forced away from the electrode surface, leading to a significant decrease in the current peak of square wave voltammetry. Subsequently, the hairpin DNA probe 2 (H2) bound to H1, freeing the TD to trigger another reaction cycle. The combination of this target-catalyzed hairpin assembly and the LBL assembly of nanomaterials achieved a detection limit of 0.1 pM with a wide linear range of 0.1-1000 pM. The sensor discriminated between mismatched DNA and the target DNA with high selectivity. This dual signal amplification strategy is relatively simple and inexpensive because it does not need any enzymes or sophisticated equipment and successfully assayed the FLT3 gene from real samples.

  13. Staphylococcus aureus - induced tumor necrosis factor - related apoptosis - inducing ligand expression mediates apoptosis and caspase-8 activation in infected osteoblasts

    Directory of Open Access Journals (Sweden)

    Bost Kenneth L

    2003-04-01

    Full Text Available Abstract Background Staphylococcus aureus infection of normal osteoblasts induces expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL. Results Normal osteoblasts were incubated in the presence of purified bacterial products over a range of concentrations. Results demonstrate that purified surface structures and a selected superantigen present in the extracellular environment are not capable of inducing TRAIL expression by osteoblasts. Osteoblasts were co-cultured with S. aureus at various multiplicities of infection utilizing cell culture chamber inserts. Results of those experiments suggest that direct contact between bacteria and osteoblasts is necessary for optimal TRAIL induction. Finally, S. aureus infection of osteoblasts in the presence of anti-TRAIL antibody demonstrates that TRAIL mediates caspase-8 activation and apoptosis of infected cells. Conclusions Collectively, these findings suggest a mechanism whereby S. aureus mediates bone destruction via induction of osteoblast apoptosis.

  14. Ligand-induced haptotropic rearrangements in bis(indenyl)zirconium sandwich complexes.

    Science.gov (United States)

    Bradley, Christopher A; Lobkovsky, Emil; Keresztes, Ivan; Chirik, Paul J

    2005-07-27

    Addition of principally sigma-donating ligands such as THF, chelating diethers, or 1,2-bis(dimethyl)phosphinoethane to eta(9),eta(5)-bis(indenyl)zirconium sandwich complexes, (eta(9)-C(9)H(5)-1,3-R(2))(eta(5)-C(9)H(5)-1,3-R(2))Zr (R = alkyl or silyl), induces haptotropic rearrangement to afford (eta(6)-C(9)H(5)-1,3-R(2))(eta(5)-C(9)H(5)-1,3-R(2))ZrL adducts. Examples where L = THF and DME have been characterized by X-ray diffraction and revealed significant buckling of the eta(6) benzo ring, consistent with reduction of the arene, and highlight the importance of the zirconium(IV) canonical form. For the THF-induced haptotropic rearrangements, the thermodynamic driving force for ring migration has been measured as a function of indenyl substituent and demonstrates silylated sandwiches favor THF coordination and the eta(6),eta(5) bonding motif over their alkylated counterparts. In the case of chelating diethers, measurement of the corresponding equilibrium constants establish more stable eta(6),eta(5) adducts with five- over four-membered chelates and with smaller oxygen and carbon backbone substituents. Kinetic studies on both THF and DME addition to (eta(9)-C(9)H(5)-1,3-(SiMe(3))(2))(eta(5)-C(9)H(5)-1,3-(SiMe(3))(2))Zr established a first-order dependence on the incoming ligand, consistent with a mechanism involving direct attack of the incoming nucleophile on the eta(9),eta(5) sandwich. These results further highlight the ability of the indenyl ligand to smoothly adjust hapticity to meet the electronic requirements of the metal center.

  15. Evidence that tumor necrosis factor-related apoptosis inducing ligand (TRAIL) inhibits angiogenesis by inducing vascular endothelial cell apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pei-Lin, E-mail: pchen@dal.ca [Department of Pathology, Dalhousie University, Halifax, Nova Scotia (Canada); Easton, Alexander S., E-mail: alexander.easton@dal.ca [Department of Pathology, Dalhousie University, Halifax, Nova Scotia (Canada); Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia (Canada); Division of Neurosurgery, Department of Surgery, Dalhousie University, Halifax, Nova Scotia (Canada)

    2010-01-01

    Tumor necrosis factor (TNF) and its related ligands TNF-related apoptosis inducing ligand (TRAIL) and Fas ligand (FasL) play roles in the regulation of vascular responses, but their effect on the formation of new blood vessels (angiogenesis) is unclear. Therefore, we have examined the effects of these ligands on angiogenesis modeled with primary cultures of human umbilical vein endothelial cells (HUVEC). To examine angiogenesis in the context of the central nervous system, we have also modeled cerebral angiogenesis with the human brain endothelial cell line hCMEC/D3. Parameters studied were bromodeoxyuridine (BrdU) incorporation and cell number (MTT) assay (to assess endothelial proliferation), scratch assay (migration) and networks on Matrigel (tube formation). In our hands, neither TRAIL nor FasL (1, 10, and 100 ng/ml) had an effect on parameters of angiogenesis in the HUVEC model. In hCMEC/D3 cells by contrast, TRAIL inhibited all parameters (10-100 ng/ml, 24 h). This was due to apoptosis, since its action was blocked by the pan-caspase inhibitor zVADfmk (5 x 10{sup -5} mol/l) and TRAIL increased caspase-3 activity 1 h after application. However FasL (100 ng/ml) increased BrdU uptake without other effects. We conclude that TRAIL has different effects on in vitro angiogenesis depending on which model is used, but that FasL is generally ineffective when applied in vitro. The data suggest that TRAIL primarily influences angiogenesis by the induction of vascular endothelial apoptosis, leading to vessel regression.

  16. Structural insights into ligand-induced activation of the insulin receptor

    Energy Technology Data Exchange (ETDEWEB)

    Ward, C.; Lawrence, M.; Streltsov, V.; Garrett, T.; McKern, N.; Lou, M.-Z.; Lovrecz, G.; Adams, T. (CSIRO); (WEHIMR)

    2008-04-29

    The current model for insulin binding to the insulin receptor proposes that there are two binding sites, referred to as sites 1 and 2, on each monomer in the receptor homodimer and two binding surfaces on insulin, one involving residues predominantly from the dimerization face of insulin (the classical binding surface) and the other residues from the hexamerization face. High-affinity binding involves one insulin molecule using its two surfaces to make bridging contacts with site 1 from one receptor monomer and site 2 from the other. Whilst the receptor dimer has two identical site 1-site 2 pairs, insulin molecules cannot bridge both pairs simultaneously. Our structures of the insulin receptor (IR) ectodomain dimer and the L1-CR-L2 fragments of IR and insulin-like growth factor receptor (IGF-1R) explain many of the features of ligand-receptor binding and allow the two binding sites on the receptor to be described. The IR dimer has an unexpected folded-over conformation which places the C-terminal surface of the first fibronectin-III domain in close juxtaposition to the known L1 domain ligand-binding surface suggesting that the C-terminal surface of FnIII-1 is the second binding site involved in high-affinity binding. This is very different from previous models based on three-dimensional reconstruction from scanning transmission electron micrographs. Our single-molecule images indicate that IGF-1R has a morphology similar to that of IR. In addition, the structures of the first three domains (L1-CR-L2) of the IR and IGF-1R show that there are major differences in the two regions governing ligand specificity. The implications of these findings for ligand-induced receptor activation will be discussed. This review summarizes the key findings regarding the discovery and characterization of the insulin receptor, the identification and arrangement of its structural domains in the sequence and the key features associated with ligand binding. The remainder of the review

  17. Ligand-induced conformational changes in wild-type and mutant yeast pyruvate kinase.

    Science.gov (United States)

    Collins, R A; Kelly, S M; Price, N C; Fothergill-Gilmore, L A; Muirhead, H

    1996-12-01

    A mutant form of pyruvate kinase in which serine 384 has been mutated to proline has been engineered in the yeast Saccharomyces cerevisiae. Residue 384 is located in a helix in a subunit interface of the tetrameric enzyme, and the mutation was anticipated to alter the conformation of the helix and hence destabilize the interface. Previous results indicate that the mutant favours the T quaternary conformation over the R conformation, and this is confirmed by the results presented here. Addition of phosphoenol-pyruvate (PEP), ADP and fructose-1, 6-bisphosphate (Fru-1.6-P2) singly to the wild-type and mutant enzymes results in a significant quenching of tryptophan fluorescence (12-44%), and for Fru-1,6-P2, a red shift of 15 nm in the emission maximum. Fluorescence titration experiments showed that PEP, ADP and Fru-1,6-P2 induce conformations which have similar ligand-binding properties in the wild-type and mutant enzymes. However, the Fru-1,6-P2 induced conformation is demonstrably different from those induced by either ADP or PEP. The enzymes differ in their susceptibility to trypsin digestion and N-ethylmaleimide inhibition. The thermal stability of the enzyme is unaltered by the mutation. Far-UV CD spectra show that both enzymes adopt a similar overall secondary structure in solution. Taken together, the results suggest that the Ser384-Pro mutation causes the enzyme to adopt a different tertiary and/or quaternary structure from the wild-type enzyme and affects the type and extent of the conformational changes induced in the enzyme upon ligand binding. A simplified minimal reaction mechanism is proposed in which the R and T states differ in both affinity and kcat. Thus, in terms of the models of cooperativity and allosteric interaction, pyruvate kinase is both a K and a V system.

  18. RHPS4 G-quadruplex ligand induces anti-proliferative effects in brain tumor cells.

    Directory of Open Access Journals (Sweden)

    Sunil Lagah

    Full Text Available BACKGROUND: Telomeric 3' overhangs can fold into a four-stranded DNA structure termed G-quadruplex (G4, a formation which inhibits telomerase. As telomerase activation is crucial for telomere maintenance in most cancer cells, several classes of G4 ligands have been designed to directly disrupt telomeric structure. METHODS: We exposed brain tumor cells to the G4 ligand 3,11-difluoro-6,8,13-trimethyl-8H-quino[4,3,2-kl]acridinium methosulfate (RHPS4 and investigated proliferation, cell cycle dynamics, telomere length, telomerase activity and activated c-Myc levels. RESULTS: Although all cell lines tested were sensitive to RHPS4, PFSK-1 central nervous system primitive neuroectodermal cells, DAOY medulloblastoma cells and U87 glioblastoma cells exhibited up to 30-fold increased sensitivity compared to KNS42 glioblastoma, C6 glioma and Res196 ependymoma cells. An increased proportion of S-phase cells were observed in medulloblastoma and high grade glioma cells whilst CNS PNET cells showed an increased proportion of G1-phase cells. RHPS4-induced phenotypes were concomitant with telomerase inhibition, manifested in a telomere length-independent manner and not associated with activated c-Myc levels. However, anti-proliferative effects were also observed in normal neural/endothelial cells in vitro and ex vivo. CONCLUSION: This study warrants in vivo validation of RHPS4 and alternative G4 ligands as potential anti-cancer agents for brain tumors but highlights the consideration of dose-limiting tissue toxicities.

  19. Myeloperoxidase formation of PAF receptor ligands induces PAF receptor-dependent kidney injury during ethanol consumption.

    Science.gov (United States)

    Latchoumycandane, Calivarathan; Nagy, Laura E; McIntyre, Thomas M

    2015-09-01

    Cytochrome P450 2E1 (CYP2E1) induction and oxidative metabolism of ethanol in hepatocytes inflame and damage liver. Chronic ethanol ingestion also induces kidney dysfunction, which is associated with mortality from alcoholic hepatitis. Whether the kidney is directly affected by ethanol or is secondary to liver damage is not established. We found that CYP2E1 was induced in kidney tubules of mice chronically ingesting a modified Lieber-deCarli liquid ethanol diet. Phospholipids of kidney tubules were oxidized and fragmented in ethanol-fed mice with accumulation of azelaoyl phosphatidylcholine (Az-PC), a nonbiosynthetic product formed only by oxidative truncation of polyunsaturated phosphatidylcholine. Az-PC stimulates the inflammatory PAF receptor (PTAFR) abundantly expressed by neutrophils and kidney tubules, and inflammatory cells and myeloperoxidase-containing neutrophils accumulated in the kidneys of ethanol-fed mice after significant hysteresis. Decreased kidney filtration and induction of the acute kidney injury biomarker KIM-1 in tubules temporally correlated with leukocyte infiltration. Genetic ablation of PTAFR reduced accumulation of PTAFR ligands and reduced leukocyte infiltration into kidneys. Loss of this receptor in PTAFR(-/-) mice also suppressed oxidative damage and kidney dysfunction without affecting CYP2E1 induction. Neutrophilic inflammation was responsible for ethanol-induced kidney damage, because loss of neutrophil myeloperoxidase in MPO(-/-) mice was similarly protective. We conclude that ethanol catabolism in renal tubules results in a self-perpetuating cycle of CYP2E1 induction, local PTAFR ligand formation, and neutrophil infiltration and activation that leads to myeloperoxidase-dependent oxidation and damage to kidney function. Hepatocytes do not express PTAFR, so this oxidative cycle is a local response to ethanol catabolism in the kidney.

  20. Reversible Intramolecular Cyclization in Ruthenium Complexes Induced by Ligand-centered One-electron Transfer on Bidentate Naphthyridine: An Important Intermediate for Both Metal– and Organo–Hydride Species

    National Research Council Canada - National Science Library

    Oyama, Dai; Ukawa, Narumi; Hamada, Takashi; Takase, Tsugiko

    2015-01-01

    ...)-1,8-naphthyridine were prepared. The complexes undergo irreversible ligand-localized one-electron reduction to form redox-induced metallacyclization between the bidentate naphthyridyl ligand and the terminal CO ligand located nearby...

  1. Light-Induced Reversible Self-Assembly of Gold Nanoparticles Surface-Immobilized with Coumarin Ligands.

    Science.gov (United States)

    He, Huibin; Feng, Miao; Chen, Qidi; Zhang, Xinqi; Zhan, Hongbing

    2016-01-18

    A novel light-induced reversible self-assembly (LIRSA) system is based on the reversible photodimerization and photocleavage of coumarin groups on the surface of gold nanoparticles (AuNPs) in THF solution. Facilitated by coumarin groups, light irradiation at 365 nm triggers the stable assembly of monodisperse AuNPs; the resulting self-assembly system can be disassembled back to the disassembled state by a relatively short exposure to benign UV light. The reversible self-assembly cycle can be repeated 4 times. A specific concentration range of coumarin ligand and the THF solvent were identified to be the two predominant factors that contribute to the LIRSA of AuNPs. This is the first successful application of reversible photodimerization based on a coumarin derivative in the field of AuNP LIRSA. This LIRSA system may provide unique opportunities for the photoregulated synthesis of many adjustable nanostructures and devices.

  2. Ligand-induced evolution of intrinsic fluorescence and catalytic activity from cobalt ferrite nanoparticles.

    Science.gov (United States)

    Pal, Monalisa; Kundu, Anirban; Rakshit, Rupali; Mandal, Kalyan

    2015-06-08

    To develop CoFe(2)O(4) as magneto-fluorescent nanoparticles (NPs) for biomedical applications, it would be advantageous to identify any intrinsic fluorescence of this important magnetic material by simply adjusting the surface chemistry of the NPs themselves. Herein, we demonstrate that intrinsic multicolor fluorescence, covering the whole visible region, can be induced by facile functionalization of CoFe(2)O(4) NPs with Na-tartrate. Moreover, the functionalized CoFe(2)O(4) NPs also show unprecedented catalytic efficiency in the degradation of both biologically and environmentally harmful dyes, pioneering the potential application of these NPs in therapeutics and wastewater treatment. Detailed investigation through various spectroscopic tools unveils the story behind the emergence of this unique optical property of CoFe(2)O(4) NPs upon functionalization with tartrate ligands. We believe our developed multifunctional CoFe(2)O(4) NPs hold great promise for advanced biomedical and technological applications.

  3. Expression of human TNF-related apoptosis-inducing ligand extracellular region in E.coli

    Institute of Scientific and Technical Information of China (English)

    唐蓓; HE; Fengtian; 等

    2002-01-01

    This study is conducted to clone the cDNA encoding human TNF-related apoptosis-inducing ligand(hTRAIL)extracellular region(amino acids 41-281,hTRAIL41-281)and to express it in E.coli.The hTRAIL41-281 cDNA is amplified by reverse transcription(RT)PCR from total RNA derived from human acute promyelocytic leukemia cell line HL-60.After sequenced,the cDNA is cloned into the vector pQE-80L and transformed into E.coli DH5α to express the recombinant hTRAIL41-281(rhTRAIL41-281)induced by IPTG.The recombinant protein is analyzed by SDS-PAGE.The cloned cDNA is consistent with the cDNA sequence encoding hTRAIL41-281 reported in GenBankTM.After inducing.the hTRAIL41-281 protein is expressed,and the mass of the recombinant protein is about 30% of total bacteria protein,which demonstrates that the cDNA encoding hTRAIL41-281 is successfully cloned and expressed in E.coli.

  4. Programming of donor T cells using allogeneic δ-like ligand 4-positive dendritic cells to reduce GVHD in mice.

    Science.gov (United States)

    Mochizuki, Kazuhiro; Meng, Lijun; Mochizuki, Izumi; Tong, Qing; He, Shan; Liu, Yongnian; Purushe, Janaki; Fung, Henry; Zaidi, M Raza; Zhang, Yanyun; Reshef, Ran; Blazar, Bruce R; Yagita, Hideo; Mineishi, Shin; Zhang, Yi

    2016-06-23

    Alloreactive T cells play a critical role in eliminating hematopoietic malignant cells but are also the mediators of graft-versus-host disease (GVHD), a major complication that subverts the success of allogeneic hematopoietic stem cell transplantation (HSCT). However, induction of alloreactive T cells does not necessarily lead to GVHD. Here we report the development of a cellular programming approach to render alloreactive T cells incapable of causing severe GVHD in both major histocompatibility complex (MHC)-mismatched and MHC-identical but minor histocompatibility antigen-mismatched mouse models. We established a novel platform that produced δ-like ligand 4-positive dendritic cells (Dll4(hi)DCs) from murine bone marrow using Flt3 ligand and Toll-like receptor agonists. Upon allogeneic Dll4(hi)DC stimulation, CD4(+) naïve T cells underwent effector differentiation and produced high levels of interferon γ (IFN-γ) and interleukin-17 in vitro, depending on Dll4 activation of Notch signaling. Following transfer, allogeneic Dll4(hi)DC-induced T cells were unable to mediate severe GVHD but preserved antileukemic activity, significantly improving the survival of leukemic mice undergoing allogeneic HSCT. This effect of Dll4(hi)DC-induced T cells was associated with their impaired expansion in GVHD target tissues. IFN-γ was important for Dll4(hi)DC programming to reduce GVHD toxicities of alloreactive T cells. Absence of T-cell IFN-γ led to improved survival and expansion of Dll4(hi)DC-induced CD4(+) T cells in transplant recipients and caused lethal GVHD. Our findings demonstrate that Dll4(hi)DC programming can overcome GVHD toxicity of donor T cells and produce leukemia-reactive T cells for effective immunotherapy.

  5. In vitro modulation of radiation-induced FAS-related apoptosis in CD34{sup +} progenitor cells by combination cytokines; Reduction de l'apoptose radio-induite impliquant le recepteur FAS au niveau des cellules hematopoietiques CD34{sup +} par une combinaison de cytokines

    Energy Technology Data Exchange (ETDEWEB)

    Drouet, M.; Mathieu, J.; Grenier, N.; Soutif, A.; Herodin, F

    1998-07-01

    Combination cytokines such as SCF, Flt-3 ligand, IL-3 and thrombopoietin can modulate Fas mRNA expression by in vitro irradiated CD34{sup +} cells which results in a moderate decrease of apoptotic ratio and an improved rate of clonogenicity of the irradiated progenitors. (authors)

  6. TNF-related apoptosis-inducing ligand cooperates with NSAIDs via activated Wnt signalling in (pre)malignant colon cells

    NARCIS (Netherlands)

    Heijink, Dianne M.; Jalving, Mathilde; Oosterhuis, Dorenda; Sloots, Ineke A.; Koster, Roelof; Hollema, Harry; Kleibeuker, Jan H.; Koornstra, Jan J.; de Vries, Elisabeth G. E.; de Jong, Steven

    2011-01-01

    TNF-related apoptosis-inducing ligand (TRAIL) receptor agonistic agents and non-steroidal anti-inflammatory drugs (NSAIDs) are interesting agents for the chemoprevention and treatment of colorectal cancer. We investigated whether NSAIDs sensitize colon cancer and adenoma cell lines and ex vivo cultu

  7. Analysing the effect of I1 imidazoline receptor ligands on DSS-induced acute colitis in mice.

    Science.gov (United States)

    Fehér, Ágnes; Tóth, Viktória E; Al-Khrasani, Mahmoud; Balogh, Mihály; Lázár, Bernadette; Helyes, Zsuzsanna; Gyires, Klára; Zádori, Zoltán S

    2017-02-01

    Imidazoline receptors (IRs) have been recognized as promising targets in the treatment of numerous diseases; and moxonidine and rilmenidine, agonists of I1-IRs, are widely used as antihypertensive agents. Some evidence suggests that IR ligands may induce anti-inflammatory effects acting on I1-IRs or other molecular targets, which could be beneficial in patients with inflammatory bowel disease (IBD). On the other hand, several IR ligands may stimulate also alpha2-adrenoceptors, which were earlier shown to inhibit, but in more recent studies to rather aggravate colitis. Hence, this study aimed to analyse for the first time the effect of various I1-IR ligands on intestinal inflammation. Colitis was induced in C57BL/6 mice by adding dextran sulphate sodium (DSS) to the drinking water for 7 days. Mice were treated daily with different IR ligands: moxonidine and rilmenidine (I1-IR agonists), AGN 192403 (highly selective I1-IR ligand, putative antagonist), efaroxan (I1-IR antagonist), as well as with the endogenous IR agonists agmatine and harmane. It was found that moxonidine and rilmenidine at clinically relevant doses, similarly to the other IR ligands, do not have a significant impact on the macroscopic and histological signs of DSS-evoked inflammation. Likewise, colonic myeloperoxidase and serum interleukin-6 levels remained unchanged in response to these agents. Thus, our study demonstrates that imidazoline ligands do not influence significantly the severity of DSS-colitis in mice and suggest that they probably neither affect the course of IBD in humans. However, the translational value of these findings needs to be verified with other experimental colitis models and human studies.

  8. Ligand-induced type II interleukin-4 receptor dimers are sustained by rapid re-association within plasma membrane microcompartments

    Science.gov (United States)

    Richter, David; Moraga, Ignacio; Winkelmann, Hauke; Birkholz, Oliver; Wilmes, Stephan; Schulte, Markos; Kraich, Michael; Kenneweg, Hella; Beutel, Oliver; Selenschik, Philipp; Paterok, Dirk; Gavutis, Martynas; Schmidt, Thomas; Garcia, K. Christopher; Müller, Thomas D.; Piehler, Jacob

    2017-07-01

    The spatiotemporal organization of cytokine receptors in the plasma membrane is still debated with models ranging from ligand-independent receptor pre-dimerization to ligand-induced receptor dimerization occurring only after receptor uptake into endosomes. Here, we explore the molecular and cellular determinants governing the assembly of the type II interleukin-4 receptor, taking advantage of various agonists binding the receptor subunits with different affinities and rate constants. Quantitative kinetic studies using artificial membranes confirm that receptor dimerization is governed by the two-dimensional ligand-receptor interactions and identify a critical role of the transmembrane domain in receptor dimerization. Single molecule localization microscopy at physiological cell surface expression levels, however, reveals efficient ligand-induced receptor dimerization by all ligands, largely independent of receptor binding affinities, in line with the similar STAT6 activation potencies observed for all IL-4 variants. Detailed spatiotemporal analyses suggest that kinetic trapping of receptor dimers in actin-dependent microcompartments sustains robust receptor dimerization and signalling.

  9. TNF-related apoptosis-inducing ligand deficiency enhances survival in murine colon ascendens stent peritonitis

    Directory of Open Access Journals (Sweden)

    Beyer K

    2016-06-01

    Full Text Available Katharina Beyer,1 Laura Stollhof,1 Christian Poetschke,2 Wolfram von Bernstorff,1 Lars Ivo Partecke,1 Stephan Diedrich,1 Stefan Maier,1 Barbara M Bröker,2 Claus-Dieter Heidecke1 1Department of General, Visceral, Thoracic, and Vascular Surgery, 2Institute of Immunology, University of Greifswald, Greifswald, GermanyBackground: Apart from inducing apoptosis in tumor cells, tumor necrosis factor (TNF-related apoptosis-inducing ligand (TRAIL influences inflammatory reactions. Murine colon ascendens stent peritonitis (CASP represents a model of diffuse peritonitis. Recently, it has been demonstrated that administration of exogenous TRAIL not only induces apoptosis in neutrophils but also enhances survival in this model. The aim of this study was to examine the impact of genetic TRAIL deficiency on the course of CASP.Methods: Peritonitis was induced in 6- to 8-week-old female TRAIL−/− mice as well as in wild-type mice. The sepsis severity score and survival of mice were monitored. Bacterial loads in blood as well as in the lymphoid organs were examined. Additionally, the number of apoptotic cells within the lymphoid organs was determined.Results: As early as 8 hours postinduction of CASP, TRAIL−/− mice were significantly more affected by sepsis than wild-type mice, as measured by the sepsis severity score. However, during the further course of sepsis, TRAIL deficiency led to significantly decreased sepsis severity scores, resulting in an enhanced overall survival in TRAIL−/− mice. The better survival of TRAIL−/− mice was accompanied by a decreased bacterial load within the blood. In marked contrast, the number of apoptotic cells within the lymphoid organs was highly increased in TRAIL−/− mice 20 hours after induction of CASP.Conclusion: Hence, exogenous and endogenous TRAIL is protective during the early phase of sepsis, while endogenous TRAIL appears to be detrimental in the later course of this disease.Keywords: CASP, mice

  10. Stability of Escherichia coli phosphoenolpyruvate carboxykinase against urea-induced unfolding and ligand effects.

    Science.gov (United States)

    Encinas, M V; Evangelio, J A; Andreu, J M; Goldie, H; Cardemil, E

    1998-07-15

    The urea-induced unfolding at pH 7.5 of Escherichia coli phosphoenolpyruvate (P-pyruvate) carboxykinase was studied by monitoring the enzyme activity, intrinsic protein fluorescence, circular dichroism spectra, and 1-anilino-8-naphthalenesulfonate binding. These studies were performed in the absence and presence of substrates and ligands. ATP or P-pyruvate plus MnCl2, or of the combined presence of ATP plus MnCl2 and oxalate, conferred great protection against urea-induced denaturation. The unfolding process showed the presence of at least one stable intermediate which is notably shifted to higher urea concentrations in the presence of substrates. This intermediate protein structure was inactive, contained less tertiary structure than the native protein and retained most of the original secondary structure. Hydrophobic surfaces were more exposed in the intermediate than in the native or unfolded species. Refolding experiments indicated that the secondary structure was completely recovered. Total recovery of tertiary structure and activity was obtained only from samples denatured at urea concentrations lower than those where the intermediate accumulates.

  11. Regulation of Cre recombinase by ligand-induced complementation of inactive fragments.

    Science.gov (United States)

    Jullien, Nicolas; Sampieri, François; Enjalbert, Alain; Herman, Jean-Paul

    2003-11-01

    Cre recombinase is extensively used to engineer the genome of experimental animals. However, its usefulness is still limited by the lack of an efficient temporal control over its activity. To overcome this, we have developed DiCre, a regulatable fragment complementation system for Cre. The enzyme was split into two moieties that were fused to FKBP12 (FK506-binding protein) and FRB (binding domain of the FKBP12-rapamycin-associated protein), respectively. These can be efficiently heterodimerized by rapamycin. Several variants, based on splitting Cre at different sites and using different linker peptides, were tested in an indicator cell line. The fusion proteins, taken separately, had no recombinase activity. Stable transformants, co-expressing complementing fragments based on splitting Cre between Asn59 and Asn60, displayed low background activity affecting 0.05-0.4% of the cells. Rapamycin induced a rapid recombination, reaching 100% by 48-72 h, with an EC50 of 0.02 nM. Thus, ligand-induced dimerization can efficiently regulate Cre, and should be useful to achieve a tight temporal control of its activity, such as in the case of the creation of conditional knock-out animals.

  12. Chemokine ligand 2 in the trigeminal ganglion regulates pain induced by experimental tooth movement.

    Science.gov (United States)

    Yang, Zhi; Luo, Wei; Wang, Jing; Tan, Yu; Fu, Runqing; Fang, Bing

    2014-07-01

    To test the hypothesis that the chemokine ligand 2/chemokine receptor 2 (CCL2/CCR2) signaling pathway plays an important role in pain induced by experimental tooth movement. Expression of CCL2/CCR2 in the trigeminal ganglion (TG) was determined by Western blotting 0 hours, 4 hours, 1 day, 3 days, 5 days, and 7 days after tooth movement. CCL2 localization and cell size distribution were revealed by immunohistochemistry. The effects of increasing force on CCL2 expression and behavioral changes were investigated. Furthermore, the effects of CCL2/CCR2 antagonists on these changes in pain behaviors were all evaluated. Exogenous CCL2 was injected into periodontal tissues and cultured TG neurons with different concentrations, and then the pain responses or c-fos expression were assessed. Experimental tooth movement led to a statistically significant increase in CCL2/CCR2 expression from day 3 to day 7, especially in small to medium-sized TG neurons. It also triggered an increase in the time spent on directed face-grooming behaviors in a force magnitude-dependent and CCL2 dose-dependent manner. Pain induced by experimental tooth movement was effectively blocked by a CCR2 antagonist and by CCL2 neutralizing antibody. Also, exogenous CCL2 led to an increase in c-fos expression in cultured TG neurons, which was blocked by CCL2 neutralizing antibody. The peripheral CCL2/CCR2 axis is modulated by experimental tooth movement and involved in the development of tooth movement pain.

  13. Regulation of Cre recombinase by ligand-induced complementation of inactive fragments

    Science.gov (United States)

    Jullien, Nicolas; Sampieri, François; Enjalbert, Alain; Herman, Jean-Paul

    2003-01-01

    Cre recombinase is extensively used to engineer the genome of experimental animals. However, its usefulness is still limited by the lack of an efficient temporal control over its activity. To overcome this, we have developed DiCre, a regulatable fragment complementation system for Cre. The enzyme was split into two moieties that were fused to FKBP12 (FK506-binding protein) and FRB (binding domain of the FKBP12–rapamycin-associated protein), respectively. These can be efficiently heterodimerized by rapamycin. Several variants, based on splitting Cre at different sites and using different linker peptides, were tested in an indicator cell line. The fusion proteins, taken separately, had no recombinase activity. Stable transformants, co-expressing complementing fragments based on splitting Cre between Asn59 and Asn60, displayed low background activity affecting 0.05–0.4% of the cells. Rapamycin induced a rapid recombination, reaching 100% by 48–72 h, with an EC50 of 0.02 nM. Thus, ligand-induced dimerization can efficiently regulate Cre, and should be useful to achieve a tight temporal control of its activity, such as in the case of the creation of conditional knock-out animals. PMID:14576331

  14. ARTD1-induced poly-ADP-ribose formation enhances PPARγ ligand binding and co-factor exchange.

    Science.gov (United States)

    Lehmann, Mareike; Pirinen, Eija; Mirsaidi, Ali; Kunze, Friedrich A; Richards, Peter J; Auwerx, Johan; Hottiger, Michael O

    2015-01-01

    PPARγ-dependent gene expression during adipogenesis is facilitated by ADP-ribosyltransferase D-type 1 (ARTD1; PARP1)-catalyzed poly-ADP-ribose (PAR) formation. Adipogenesis is accompanied by a dynamic modulation of the chromatin landscape at PPARγ target genes by ligand-dependent co-factor exchange. However, how endogenous PPARγ ligands, which have a low affinity for the receptor and are present at low levels in the cell, can induce sufficient co-factor exchange is unknown. Moreover, the significance of PAR formation in PPARγ-regulated adipose tissue function is also unknown. Here, we show that inhibition of PAR formation in mice on a high-fat diet reduces weight gain and cell size of adipocytes, as well as PPARγ target gene expression in white adipose tissue. Mechanistically, topoisomerase II activity induces ARTD1 recruitment to PPARγ target genes, and ARTD1 automodification enhances ligand binding to PPARγ, thus promoting sufficient transcriptional co-factor exchange in adipocytes. Thus, ARTD1-mediated PAR formation during adipogenesis is necessary to adequately convey the low signal of endogenous PPARγ ligand to effective gene expression. These results uncover a new regulatory mechanism of ARTD1-induced ADP-ribosylation and highlight its importance for nuclear factor-regulated gene expression. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Ligand-induced Ordering of the C-terminal Tail Primes STING for Phosphorylation by TBK1

    Directory of Open Access Journals (Sweden)

    Yuko Tsuchiya

    2016-07-01

    Full Text Available The innate immune protein Stimulator of interferon genes (STING promotes the induction of interferon beta (IFN-β production via the phosphorylation of its C-terminal tail (CTT by TANK-binding kinase 1 (TBK1. Potent ligands of STING are, therefore, promising candidates for novel anti-cancer drugs or vaccine adjuvants. However, the intrinsically flexible CTT poses serious problems in in silico drug discovery. Here, we performed molecular dynamics simulations of the STING fragment containing the CTT in ligand-bound and unbound forms and observed that the binding of a potent ligand cyclic GMP-AMP (cGAMP induced a local structure in the CTT, reminiscent of the known structure of a TBK1 substrate. The subsequent molecular biological experiments confirmed the observed dynamics of the CTT and identified essential residues for the activation of the IFN-β promoter, leading us to propose a new mechanism of STING activation.

  16. Staphylococcus aureus PSM peptides induce tolerogenic dendritic cells upon treatment with ligands of extracellular and intracellular TLRs.

    Science.gov (United States)

    Armbruster, Nicole S; Richardson, Jennifer R; Schreiner, Jens; Klenk, Juliane; Günter, Manina; Autenrieth, Stella E

    2016-12-01

    Dendritic cells (DCs) are key players of the immune system and thus a target for immune evasion by pathogens. We recently showed that the virulence factor phenol-soluble modulin (PSM) produced by community-associated methicillin-resistant Staphylococcus aureus strains induces tolerogenic DCs upon Toll-like receptor (TLR) 2 activation via the p38-CREB-IL-10 pathway. Here, we addressed the question whether this tolerogenic phenotype of DCs induced by PSMs is specific for TLR2 activation. Therefore, bone marrow-derived DCs were treated with various ligands for extracellular and intracellular TLRs simultaneously with PSMα3. We show that PSMα3 modulates antigen uptake, maturation and cytokine production of DCs activated by TLR1/2, TLR2/6, TLR4, TLR7, and TLR9. Pre-incubation of DCs with a p38 MAP kinase inhibitor prevented the PSMα3-induced IL-10 secretion, as well as MHC class II up-regulation upon TLR activation. In consequence, the tolerogenic DCs induced by PSMα3 in response to several TLR ligands promoted priming of regulatory T cells. Thus, PSMs could be useful as inducers of tolerogenic DCs upon TLR ligand stimulation for therapeutic applications.

  17. Peroxisome proliferator-activated receptor γ ligands induce cell cycle arrest and apoptosis in human renal carcinoma cell lines

    Institute of Scientific and Technical Information of China (English)

    Feng-guang YANG; Zhi-wen ZHANG; Dian-qi XIN; Chang-jin SHI; Jie-ping WU; Ying-lu GUO; You-fei GUAN

    2005-01-01

    Aim: To study the effect of peroxisome proliferator-actived receptor γ (PPARγ)ligands on cell proliferation and apoptosis in human renal carcinoma cell lines.Methods: The expression of PPARγ was investigated by reverse transcriptase polymerase chain reaction (RT-PCR), Western blot and immunohistochemistry.The effect of thiazolidinedione (TZD) PPARγ ligands on growth of renal cell carcinoma (RCC) cells was measured by MTT assay and flow cytometric analysis. Cell death ELISA, Hoechst 33342 fluorescent staining and DNA ladder assay were used to observe the effects of PPARγ ligands on apoptosis. Regulatory proteins of cell cycle and apoptosis were detected by Western blot analysis. Results:PPARγ was expressed at much higher levels in renal tumors than in the normal kidney (2.16±0.85 vs 0.90±0.73; P<0.01 ). TZD PPARγ ligands inhibited RCC cell growth in a dose-dependent manner with IC50 values of 7.08 μmol/L and 11.32 μmol/L for pioglitazone, and 5.71 μmol/L and 8.38 μmol/L for troglitazone in 786-O and A498 cells, respectively. Cell cycle analysis showed a G0/G1 arrest in human RCC cells following 24-h exposure to TZD. Analysis of cell cycle regulatory proteins revealed that TZD decreased the protein levels of proliferating cell nuclear antigen, pRb, cyclin D1, and Cdk4 but increased the levels of p21 and p27 in a timedependent manner. Furthermore, high doses of TZD induced massive apoptosis in renal cancer cells, with increased Bax expression and decreased Bcl-2 expression.Conclusion: TZD PPARγ ligands showed potent inhibitory effect on proliferation,and could induce apoptosis in RCC cells. These results suggest that ligands for PPARγ have potential antitumor effects on renal carcinoma cells.

  18. The aryl hydrocarbon receptor ligand ITE inhibits TGFβ1-induced human myofibroblast differentiation.

    Science.gov (United States)

    Lehmann, Geniece M; Xi, Xia; Kulkarni, Ajit A; Olsen, Keith C; Pollock, Stephen J; Baglole, Carolyn J; Gupta, Shikha; Casey, Ann E; Huxlin, Krystel R; Sime, Patricia J; Feldon, Steven E; Phipps, Richard P

    2011-04-01

    Fibrosis can occur in any human tissue when the normal wound healing response is amplified. Such amplification results in fibroblast proliferation, myofibroblast differentiation, and excessive extracellular matrix deposition. Occurrence of these sequelae in organs such as the eye or lung can result in severe consequences to health. Unfortunately, medical treatment of fibrosis is limited by a lack of safe and effective therapies. These therapies may be developed by identifying agents that inhibit critical steps in fibrotic progression; one such step is myofibroblast differentiation triggered by transforming growth factor-β1 (TGFβ1). In this study, we demonstrate that TGFβ1-induced myofibroblast differentiation is blocked in human fibroblasts by a candidate endogenous aryl hydrocarbon receptor (AhR) ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE). Our data show that ITE disrupts TGFβ1 signaling by inhibiting the nuclear translocation of Smad2/3/4. Although ITE functions as an AhR agonist, and biologically persistent AhR agonists, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin, cause severe toxic effects, ITE exhibits no toxicity. Interestingly, ITE effectively inhibits TGFβ1-driven myofibroblast differentiation in AhR(-/-) fibroblasts: Its ability to inhibit TGFβ1 signaling is AhR independent. As supported by the results of this study, the small molecule ITE inhibits myofibroblast differentiation and may be useful clinically as an antiscarring agent.

  19. TLR2 ligands induce NF-κB activation from endosomal compartments of human monocytes.

    Directory of Open Access Journals (Sweden)

    Karim J Brandt

    Full Text Available Localization of Toll-like receptors (TLR in subcellular organelles is a major strategy to regulate innate immune responses. While TLR4, a cell-surface receptor, signals from both the plasma membrane and endosomal compartments, less is known about the functional role of endosomal trafficking upon TLR2 signaling. Here we show that the bacterial TLR2 ligands Pam3CSK4 and LTA activate NF-κB-dependent signaling from endosomal compartments in human monocytes and in a NF-κB sensitive reporter cell line, despite the expression of TLR2 at the cell surface. Further analyses indicate that TLR2-induced NF-κB activation is controlled by a clathrin/dynamin-dependent endocytosis mechanism, in which CD14 serves as an important upstream regulator. These findings establish that internalization of cell-surface TLR2 into endosomal compartments is required for NF-κB activation. These observations further demonstrate the need of endocytosis in the activation and regulation of TLR2-dependent signaling pathways.

  20. SDF-1α-induced dual pairs of E-selectin/ligand mediate endothelial progenitor cell homing to critical ischemia.

    Science.gov (United States)

    Liu, Zhao-Jun; Tian, Runxia; Li, Yan; Zhang, Leiming; Shao, Hongwei; Yang, Cuixia; Velazquez, Omaida C

    2016-10-07

    Homing of endothelial progenitor cells (EPC) to the ischemic tissues is a key event in neovascularization and tissue regeneration. In response to ischemic insult, injured tissues secrete several chemo-cytokines, including stromal cell-derived factor-1α (SDF-1α), which triggers mobilization and homing of bone marrow-derived EPC (BMD-EPC). We previously reported that SDF-1α-induced EPC homing is mediated by a panel of adhesion molecules highly or selectively expressed on the activated endothelium in ischemic tissues, including E-selectin. Elevated E-selectin on wound vasculature serve as docking sites for circulating EPC, which express counterpart E-selectin ligands. Here, we show that SDF-1α presented in wound tissue and released into circulation can act both locally and remotely to induce ischemic tissue endothelium and BMD-EPC to express both E-selectin and its ligands. By performing BM transplantation using E-selectin(-/-) and E-selectin(+/+) mice as the donors and recipients respectively, we demonstrate that upregulated dual E-selectin/ligand pairs reciprocally expressed on ischemic tissue endothelium and BMD-EPC act as double-locks to secure targeted EPC- endothelium interactions by which to facilitate EPC homing and promote neovascularization and tissue repair. These findings describe a novel mechanism for BMD-EPC homing and indicate that dual E-selectin/ligand pairs may be effective targets/tools for therapeutic neovascularization and targeted cell delivery.

  1. PGE2/EP3/SRC signaling induces EGFR nuclear translocation and growth through EGFR ligands release in lung adenocarcinoma cells

    Science.gov (United States)

    Bazzani, Lorenzo; Donnini, Sandra; Finetti, Federica; Christofori, Gerhard; Ziche, Marina

    2017-01-01

    Prostaglandin E2 (PGE2) interacts with tyrosine kinases receptor signaling in both tumor and stromal cells supporting tumor progression. Here we demonstrate that in non-small cell lung carcinoma (NSCLC) cells, A549 and GLC82, PGE2 promotes nuclear translocation of epidermal growth factor receptor (nEGFR), affects gene expression and induces cell growth. Indeed, cyclin D1, COX-2, iNOS and c-Myc mRNA levels are upregulated following PGE2 treatment. The nuclear localization sequence (NLS) of EGFR as well as its tyrosine kinase activity are required for the effect of PGE2 on nEGFR and downstream signaling activities. PGE2 binds its bona fide receptor EP3 which by activating SRC family kinases, induces ADAMs activation which, in turn, releases EGFR-ligands from the cell membrane and promotes nEGFR. Amphiregulin (AREG) and Epiregulin (EREG) appear to be involved in nEGFR promoted by the PGE2/EP3-SRC axis. Pharmacological inhibition or silencing of the PGE2/EP3/SRC-ADAMs signaling axis or EGFR ligands i.e. AREG and EREG expression abolishes nEGFR induced by PGE2. In conclusion, PGE2 induces NSCLC cell proliferation by EP3 receptor, SRC-ADAMs activation, EGFR ligands shedding and finally, phosphorylation and nEGFR. Since nuclear EGFR is a hallmark of cancer aggressiveness, our findings reveal a novel mechanism for the contribution of PGE2 to tumor progression. PMID:28415726

  2. Downregulation of the stress-induced ligand ULBP1 following SV40 infection confers viral evasion from NK cell cytotoxicity.

    Science.gov (United States)

    Bauman, Yoav; Drayman, Nir; Ben-Nun-Shaul, Orly; Vitenstein, Alon; Yamin, Rachel; Ophir, Yael; Oppenheim, Ariella; Mandelboim, Ofer

    2016-03-29

    Polyomaviruses are a diverse family of viruses which are prevalent in the human population. However, the interactions of these viruses with the immune system are not well characterized. We have previously shown that two human polyomaviruses, JC and BK, use an identical microRNA to evade immune attack by Natural Killer (NK) cells. We showed that this viral microRNA suppresses ULBP3 expression, a stress induced ligand for the killer receptor NKG2D. Here we show that Simian Virus 40 (SV40) also evades NK cell attack through the down regulation of another stress-induced ligand of NKG2D, ULBP1. These findings indicate that NK cells play an essential role in fighting polyomavirus infections and further emphasize the importance of various members of the ULBP family in controlling polyomavirus infection.

  3. Receptor activator for nuclear factor-κB ligand signaling promotes progesterone-mediated estrogen-induced mammary carcinogenesis

    OpenAIRE

    Boopalan, Thiyagarajan; Arumugam, Arunkumar; Parada, Jacqueline; Saltzstein, Edward; Lakshmanaswamy, Rajkumar

    2015-01-01

    Breast cancer is a leading cause of cancer-related death in women. Prolonged exposure to the ovarian hormones estrogen and progesterone increases the risk of breast cancer. Although estrogen is known as a primary factor in mammary carcinogenesis, very few studies have investigated the role of progesterone. Receptor activator for nuclear factor-κB (NF-κB) ligand (RANKL) plays an important role in progesterone-induced mammary carcinogenesis. However, the molecular mechanism underlying RANKL-ind...

  4. Killer B Lymphocytes and their Fas Ligand Positive Exosomes as Inducers of Immune Tolerance

    Directory of Open Access Journals (Sweden)

    Steven Karl Lundy

    2015-03-01

    Full Text Available Induction of immune tolerance is a key process by which the immune system is educated to modulate reactions against benign stimuli such as self-antigens and commensal microbes. Understanding and harnessing the natural mechanisms of immune tolerance may become an increasingly useful strategy for treating many types of allergic and autoimmune diseases, as well as for improving the acceptance of solid organ transplants. Our laboratory and others have been interested in the natural ability of some B lymphocytes to express the death-inducing molecule Fas ligand (FasL, and their ability to kill T helper (TH lymphocytes. We have recently shown that experimental transformation of human B cells by a non-replicative variant of Epstein-Barr virus (EBV consistently resulted in high expression of functional FasL protein. The production and release of FasL+ exosomes that co-expressed MHC Class II molecules and had the capacity to kill antigen-specific TH cells was also observed. Several lines of evidence indicate that FasL+ B cells and FasL+MHCII+ exosomes have important roles in natural immune tolerance and have a great deal of therapeutic potential. Taken together, these findings suggest that EBV-immortalized human B lymphoblastoid cell lines could be used as cellular factories for FasL+ exosomes, which would be employed to therapeutically establish and/or regain immune tolerance toward specific antigens. The goals of this review are to summarize current knowledge of the roles of FasL+ B cells and exosomes in immune regulation, and to suggest methods of manipulating killer B cells and FasL+ exosomes for clinical purposes.

  5. Neurite outgrowth induced by a synthetic peptide ligand of neural cell adhesion molecule requires fibroblast growth factor receptor activation

    DEFF Research Database (Denmark)

    Rønn, L C; Doherty, P; Holm, A;

    2000-01-01

    The neural cell adhesion molecule NCAM is involved in axonal outgrowth and target recognition in the developing nervous system. In vitro, NCAM-NCAM binding has been shown to induce neurite outgrowth, presumably through an activation of fibroblast growth factor receptors (FGFRs). We have recently...... identified a neuritogenic ligand, termed the C3 peptide, of the first immunoglobulin (lg) module of NCAM using a combinatorial library of synthetic peptides. Here we investigate whether stimulation of neurite outgrowth by this synthetic ligand of NCAM involves FGFRs. In primary cultures of cerebellar neurons...... from wild-type mice, the C3 peptide stimulated neurite outgrowth. This response was virtually absent in cultures of cerebellar neurons from transgenic mice expressing a dominant-negative form of the FGFR1. Likewise, in PC12E2 cells transiently expressing a dominant-negative form of the mouse FGFR1...

  6. Inhibition of matrix metalloproteinase-9 activity by doxycycline ameliorates RANK ligand-induced osteoclast differentiation in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Gilson C.N. [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Pharmacology, FOP/UNICAMP, Piracicaba, SP (Brazil); Kajiya, Mikihito [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA (United States); Nakanishi, Tadashi [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Ohta, Kouji [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA (United States); Rosalen, Pedro L.; Groppo, Francisco C. [Department of Pharmacology, FOP/UNICAMP, Piracicaba, SP (Brazil); Ernst, Cory W.O.; Boyesen, Janie L. [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Bartlett, John D.; Stashenko, Philip [Department of Cytokine Biology, Forsyth Institute, Cambridge, MA (United States); Taubman, Martin A. [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Kawai, Toshihisa, E-mail: tkawai@forsyth.org [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA (United States)

    2011-06-10

    Tetracycline antibiotics, including doxycycli/e (DOX), have been used to treat bone resorptive diseases, partially because of their activity to suppress osteoclastogenesis induced by receptor activator of nuclear factor kappa B ligand (RANKL). However, their precise inhibitory mechanism remains unclear. Therefore, the present study examined the effect of Dox on osteoclastogenesis signaling induced by RANKL, both in vitro and in vivo. Although Dox inhibited RANKL-induced osteoclastogenesis and down-modulated the mRNA expression of functional osteoclast markers, including tartrate-resistant acid phosphatase (TRAP) and cathepsin K, Dox neither affected RANKL-induced MAPKs phosphorylation nor NFATc1 gene expression in RAW264.7 murine monocytic cells. Gelatin zymography and Western blot analyses showed that Dox down-regulated the enzyme activity of RANKL-induced MMP-9, but without affecting its protein expression. Furthermore, MMP-9 enzyme inhibitor also attenuated both RANKL-induced osteoclastogenesis and up-regulation of TRAP and cathepsin K mRNA expression, indicating that MMP-9 enzyme action is engaged in the promotion of RANKL-induced osteoclastogenesis. Finally, Dox treatment abrogated RANKL-induced osteoclastogenesis and TRAP activity in mouse calvaria along with the suppression of MMP9 enzyme activity, again without affecting the expression of MMP9 protein. These findings suggested that Dox inhibits RANKL-induced osteoclastogenesis by its inhibitory effect on MMP-9 enzyme activity independent of the MAPK-NFATc1 signaling cascade.

  7. Drug Discovery against Psoriasis: Identification of a New Potent FMS-like Tyrosine Kinase 3 (FLT3) Inhibitor, 1-(4-((1H-Pyrazolo[3,4-d]pyrimidin-4-yl)oxy)-3-fluorophenyl)-3-(5-(tert-butyl)isoxazol-3-yl)urea, That Showed Potent Activity in a Psoriatic Animal Model.

    Science.gov (United States)

    Li, Guo-Bo; Ma, Shuang; Yang, Ling-Ling; Ji, Sen; Fang, Zhen; Zhang, Guo; Wang, Li-Jiao; Zhong, Jie-Min; Xiong, Yu; Wang, Jiang-Hong; Huang, Shen-Zhen; Li, Lin-Li; Xiang, Rong; Niu, Dawen; Chen, Ying-Chun; Yang, Sheng-Yong

    2016-09-22

    Psoriasis is a chronic T-cell-mediated autoimmune disease, and FMS-like tyrosine kinase 3 (FLT3) has been considered as a potential molecular target for the treatment of psoriasis. In this investigation, structural optimization was performed on a lead compound, 1-(4-(1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)phenyl)-3-(4-chloro-3-(trifluoromethyl)phenyl)urea (1), which showed a moderate inhibitory activity againt FLT3. A series of pyrazolo[3,4-d]pyrimidine derivatives were synthesized, and structure-activity relationship analysis led to the discovery of a number of potent FLT3 inhibitors. One of the most active compounds, 1-(4-(1H-pyrazolo[3,4-d]pyrimidin-4-yloxy)-3-fluorophenyl)-3-(5-tert-butylisoxazol-3-yl)urea (18b), was then chosen for in-depth antipsoriasis studies because this compound displayed the highest potency in a preliminary antipsoriasis test. Compound 18b exhibited significant antipsoriatic effects in the K14-VEGF transgenic mouse model of psoriasis, and no recurrence was found 15 days later after the last administration. Detailed mechanisms of action of compound 18b were also investigated. Collectively, compound 18b could be a potential drug candidate for psoriasis treatment.

  8. Leptin induces CYP1B1 expression in MCF-7 cells through ligand-independent activation of the ERα pathway

    Energy Technology Data Exchange (ETDEWEB)

    Khanal, Tilak; Kim, Hyung Gyun; Do, Minh Truong; Choi, Jae Ho; Won, Seong Su [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Kang, Wonku [College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Chung, Young Chul [Department of Food Science and Culinary, International University of Korea, Jinju (Korea, Republic of); Jeong, Tae Cheon, E-mail: taecheon@ynu.ac.kr [College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Jeong, Hye Gwang, E-mail: hgjeong@cnu.ac.kr [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of)

    2014-05-15

    Leptin, a hormone with multiple biological actions, is produced predominantly by adipose tissue. Among its functions, leptin can stimulate tumour cell growth. Oestrogen receptor α (ERα), which plays an essential role in breast cancer development, can be transcriptionally activated in a ligand-independent manner. In this study, we investigated the effect of leptin on CYP1B1 expression and its mechanism in breast cancer cells. Leptin induced CYP1B1 protein, messenger RNA expression and promoter activity in ERα-positive MCF-7 cells but not in ERα-negative MDA-MB-231 cells. Additionally, leptin increased 4-hydroxyoestradiol in MCF-7 cells. Also, ERα knockdown by siRNA significantly blocked the induction of CYP1B1 expression by leptin, indicating that leptin induced CYP1B1 expression via an ERα-dependent mechanism. Transient transfection with CYP1B1 deletion promoter constructs revealed that the oestrogen response element (ERE) plays important role in the up-regulation of CYP1B1 by leptin. Furthermore, leptin stimulated phosphorylation of ERα at serine residues 118 and 167 and increased ERE-luciferase activity, indicating that leptin induced CYP1B1 expression by ERα activation. Finally, we found that leptin activated ERK and Akt signalling pathways, which are upstream kinases related to ERα phosphorylation induced by leptin. Taken together, our results indicate that leptin-induced CYP1B1 expression is mediated by ligand-independent activation of the ERα pathway as a result of the activation of ERK and Akt in MCF-7 cells. - Highlights: • Leptin increased 4-hydroxyoestradiol in MCF-7 breast cancer cells. • Leptin activated ERK and Akt kinases related to ERα phosphorylation. • Leptin induces phosphorylation of ERα at serine residues 118 and 167. • Leptin induces ERE-luciferase activity.

  9. Essential dynamics of the cellular retinol-binding protein - Evidence for ligand-induced conformational changes

    NARCIS (Netherlands)

    van Aalten, D.M.F.; Findlay, J.B.C.; Amadei, A; Berendsen, H.J.C.

    1995-01-01

    The cellular retinol-binding protein (CRBP) is an intracellular retinol carrier protein belonging to a family of hydrophobic ligand-binding proteins, It transports retinol to specific locations in the cell where, for instance, it is esterified for storage, Recently solved crystallographic structures

  10. Iron-binding ligands in Dutch estuaries are not affected by UV induced photochemical degradation

    NARCIS (Netherlands)

    Rijkenberg, MJA; Gerringa, LJA; Velzeboer, [No Value; Timmermans, KR; Buma, AGJ; de Baar, HJW; Gerringa, Loes J.A.; Velzeboer, Ilona; Timmermans, Klaas R.; Baar, Hein J.W. de

    2006-01-01

    This study shows that ultraviolet B (UV-B: 280-315 nm) and UV-A (315-400 nm) have no significant influence on the photodegradation of organic Fe(III)-binding ligands in estuarine waters from Marsdiep and Scheldt (The Netherlands). High salinity estuarine seawater from the Marsdiep and Scheldt

  11. Programmed Death Ligand 1 Promotes Early-Life Chlamydia Respiratory Infection-Induced Severe Allergic Airway Disease.

    Science.gov (United States)

    Starkey, Malcolm R; Nguyen, Duc H; Brown, Alexandra C; Essilfie, Ama-Tawiah; Kim, Richard Y; Yagita, Hideo; Horvat, Jay C; Hansbro, Philip M

    2016-04-01

    Chlamydia infections are frequent causes of respiratory illness, particularly pneumonia in infants, and are linked to permanent reductions in lung function and the induction of asthma. However, the immune responses that protect against early-life infection and the mechanisms that lead to chronic lung disease are incompletely understood. In the current study, we investigated the role of programmed death (PD)-1 and its ligands PD-L1 and PD-L2 in promoting early-life Chlamydia respiratory infection, and infection-induced airway hyperresponsiveness (AHR) and severe allergic airway disease in later life. Infection increased PD-1 and PD-L1, but not PD-L2, mRNA expression in the lung. Flow cytometric analysis of whole lung homogenates identified monocytes, dendritic cells, CD4(+), and CD8(+) T cells as major sources of PD-1 and PD-L1. Inhibition of PD-1 and PD-L1, but not PD-L2, during infection ablated infection-induced AHR in later life. Given that PD-L1 was the most highly up-regulated and its targeting prevented infection-induced AHR, subsequent analyses focused on this ligand. Inhibition of PD-L1 had no effect on Chlamydia load but suppressed infection-induced pulmonary inflammation. Infection decreased the levels of the IL-13 decoy receptor in the lung, which were restored to baseline levels by inhibition of PD-L1. Finally, inhibition of PD-L1 during infection prevented subsequent infection-induced severe allergic airways disease in later life by decreasing IL-13 levels, Gob-5 expression, mucus production, and AHR. Thus, early-life Chlamydia respiratory infection-induced PD-L1 promotes severe inflammation during infection, permanent reductions in lung function, and the development of more severe allergic airway disease in later life.

  12. The dietary flavonoid apigenin sensitizes malignant tumor cells to tumor necrosis factor-related apoptosis-inducing ligand.

    Science.gov (United States)

    Horinaka, Mano; Yoshida, Tatsushi; Shiraishi, Takumi; Nakata, Susumu; Wakada, Miki; Sakai, Toshiyuki

    2006-04-01

    Dietary flavonoid apigenin is expected to have preventive and therapeutic potential against malignant tumors. In this report, we show for the first time that apigenin markedly induces the expression of death receptor 5 (DR5) and synergistically acts with exogenous soluble recombinant human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to induce apoptosis in malignant tumor cells. TRAIL is a promising candidate for cancer therapeutics due to its ability to selectively induce apoptosis in cancer cells. The combined use of apigenin and TRAIL at suboptimal concentrations induces Bcl-2-interacting domain cleavage and the activation of caspases-8, -10, -9, and -3. Furthermore, human recombinant DR5/Fc chimera protein and caspase inhibitors dramatically inhibit apoptosis induced by the combination of apigenin and TRAIL. On the other hand, apigenin-mediated induction of DR5 expression is not observed in normal human peripheral blood mononuclear cells. Moreover, apigenin does not sensitize normal human peripheral blood mononuclear cells to TRAIL-induced apoptosis. These results suggest that this combined treatment with apigenin and TRAIL might be promising as a new therapy against malignant tumors.

  13. Expression of tumor necrosis factor related apoptosis inducing ligand receptor in glioblastoma

    Institute of Scientific and Technical Information of China (English)

    Dongling Gao; Zhongwei Zhao; Hongxin Zhang; Lan Zhang; Kuisheng Chen; Yunhan Zhang

    2008-01-01

    BACKGROUND: Receptors for tumor necrosis factor related apoptosis inducing ligand (TRAIL) include death receptor 4, death receptor 5, decoy receptor 1, and decoy receptor 2. Activation of death receptor 4 and 5 selectively kills tumor cells.OBJECTIVE: To detect TRAIL receptor expression in glioblastoma by immunohistochemistry and RT-PCR and to compare this expression to that in normal brain tissue.DESIGN: Observational analysis.SETTING: Department of Pathology, the First Affiliated Hospital of Zhengzhou University; Henan Tumor Pathology Key Laboratory.PARTICIPANTS: Twenty-five patients (17 males and 8 females) who received glioblastoma resection were selected from the Fifth Affiliated Hospital of Zhengzhou University, between September 2003 to June 2004. All glioblastoma samples were diagnosed pathologically. Twenty patients (12 males and 8 females) with craniocerebral injury who received normal brain tissue resection were selected in the same time period. There were no significant differences in sex and age between glioblastoma patients or between craniocerebral injury patients (P>0.05). All patients and appropriate relatives provided informed consent, and this study was approved by the local research ethics committee.METHODS: Polyclonal antibody against TRAIL receptors and an immunohistochemical kit (batch number: 200502) were purchased from Boster Company, Wuhan. Immunohistochemistry: Expression of death receptor 4, death receptor 5, decoy receptor 1, and decoy receptor 2 were observed in both glioblastoma and normal brain tissue. The experiment was performed according to the kit instructions, and positive staining was brown-yellow. Assessment: There were no positive signals (-); weakly positive signals, positive cells75% (++++). Evaluation: Expression levels of TRAIL receptors were estimated in both normal brain tissue and glioblastoma. Expression of decoy receptor 1 and decoy receptor 2 mRNA in glioblastoma were detected by reverse transcription polymerase

  14. Retracted: FLT3: beyond good and evil.

    Science.gov (United States)

    Lagunas-Rangel, Francisco Alejandro; Cortes-Penagos, Carlos; Viveros-Sandoval, Martha Eva

    2016-07-29

    The above article, published online on 29 July 2016 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the Journal Editor in Chief, Journal Production Manager, and John Wiley & Sons, Ltd. The retraction has been agreed due to 48% similar significant between this article and an article published in Nature Reviews Cancer journal. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Regulation of Estrogen Receptor Nuclear Export by Ligand-Induced and p38-Mediated Receptor Phosphorylation

    OpenAIRE

    Lee, Heehyoung; Bai, Wenlong

    2002-01-01

    Estrogen receptors are phosphoproteins which can be activated by ligands, kinase activators, or phosphatase inhibitors. Our previous study showed that p38 mitogen-activated protein kinase was involved in estrogen receptor activation by estrogens and MEKK1. Here, we report estrogen receptor-dependent p38 activation by estrogens in endometrial adenocarcinoma cells and in vitro and in vivo phosphorylation of the estrogen receptor α mediated through p38. The phosphorylation site was identified as...

  16. Roles for stress-inducible lambda glutathione transferases in flavonoid metabolism in plants as identified by ligand fishing.

    Science.gov (United States)

    Dixon, David P; Edwards, Robert

    2010-11-19

    The glutathione transferases (GSTs) of plants are a superfamily of abundant enzymes whose roles in endogenous metabolism are largely unknown. For example, the lambda class of GSTs (GSTLs) have members that are selectively induced by chemical stress treatments and based on their enzyme chemistry are predicted to have roles in redox homeostasis. However, using conventional approaches these functions have yet to be determined. To address this, recombinant GSTLs from wheat and Arabidopsis were tagged with a Strep tag and after affinity-immobilization, incubated with extracts from Arabidopsis, tobacco, and wheat. Bound ligands were then recovered by solvent extraction and identified by mass spectrometry (MS). With the wheat enzyme TaGSTL1, the ligand profiles obtained with in vitro extracts from tobacco closely matched those observed after the protein had been expressed in planta, demonstrating that these associations were physiologically representative. The stress-inducible TaGSTL1 was found to selectively recognize flavonols (e.g. taxifolin; K(d) = 25 nM), with this binding being dependent upon S-glutathionylation of an active site cysteine. In the case of the wheat extracts, this selectivity in ligand recognitions lead to the detection of flavonols that had not been previously described in this cereal. Subsequent in vitro assays showed that the co-binding of flavonols, such as quercetin, to the thiolated TaGSTL1 represented an intermediate step in the reduction of the respective S-glutathionylated quinone derivatives to yield free flavonols. These results suggest a novel role for GSTLs in maintaining the flavonoid pool under stress conditions.

  17. Ligand-induced internalization of the type 1 cholecystokinin receptor independent of recognized signaling activity.

    Science.gov (United States)

    Cawston, Erin E; Harikumar, Kaleeckal G; Miller, Laurence J

    2012-02-01

    Receptor ligands, identified as antagonists, based on the absence of stimulation of signaling, can rarely stimulate receptor internalization. d-Tyr-Gly-[(Nle(28,31),d-Trp(30))CCK-26-32]-2-phenylethyl ester (d-Trp-OPE) is such a ligand that binds to the cholecystokinin (CCK) receptor and stimulates internalization. Here, the molecular basis of this trafficking event is explored, with the assumption that ligand binding initiates conformational change, exposing an epitope to direct endocytosis. Ligand-stimulated internalization was studied morphologically using fluorescent CCK and d-Trp-OPE. d-Trp-OPE occupation of Chinese hamster ovary cell receptors stimulated internalization into the same region as CCK. Arrestin-biased action was ruled out using morphological translocation of fluorescent arrestin 2 and arrestin 3, moving to the membrane in response to CCK, but not d-Trp-OPE. Possible roles of the carboxyl terminus were studied using truncated receptor constructs, eliminating the proline-rich distal tail, the serine/threonine-rich midregion, and the remainder to the vicinal cysteines. None of these constructs disrupted d-Trp-OPE-stimulated internalization. Possible contributions of transmembrane segments were studied using competitive inhibition with peptides that also had no effect. Intracellular regions were studied with a similar strategy using coexpressing cell lines. Peptides corresponding to ends of each loop region were studied, with only the peptide at the carboxyl end of the third loop inhibiting d-Trp-OPE-stimulated internalization but having no effect on CCK-stimulated internalization. The region contributing to this effect was refined to peptide 309-323, located below the recognized G protein-association motif. While a receptor in which this segment was deleted did internalize in response to d-Trp-OPE, it exhibited abnormal ligand binding and did not signal in response to CCK, suggesting an abnormal conformation and possible mechanism of internalization

  18. Systemically Administered Ligands of Toll-Like Receptor 2, -4, and -9 Induce Distinct Inflammatory Responses in the Murine Lung

    Directory of Open Access Journals (Sweden)

    H. Ehrentraut

    2011-01-01

    Full Text Available Objective. To determine whether systemically administered TLR ligands differentially modulate pulmonary inflammation. Methods. Equipotent doses of LPS (20 mg/kg, CpG-ODN (1668-thioat 1 nmol/g, or LTA (15 mg/kg were determined via TNF activity assay. C57BL/6 mice were challenged intraperitoneally. Pulmonary NFκB activation (2 h and gene expression/activity of key inflammatory mediators (4 h were monitored. Results. All TLR ligands induced NFκB. LPS increased the expression of TLR2, 6, and the cytokines IL-1αβ, TNF-α, IL-6, and IL-12p35/p40, CpG-ODN raised TLR6, TNF-α, and IL12p40. LTA had no effect. Additionally, LPS increased the chemokines MIP-1α/β, MIP-2, TCA-3, eotaxin, and IP-10, while CpG-ODN and LTA did not. Myeloperoxidase activity was highest after LPS stimulation. MMP1, 3, 8, and 9 were upregulated by LPS, MMP2, 8 by CpG-ODN and MMP2 and 9 by LTA. TIMPs were induced only by LPS. MMP-2/-9 induction correlated with their zymographic activities. Conclusion. Pulmonary susceptibility to systemic inflammation was highest after LPS, intermediate after CpG-ODN, and lowest after LTA challenge.

  19. Propionic acid secreted from propionibacteria induces NKG2D ligand expression on human-activated T lymphocytes and cancer cells

    DEFF Research Database (Denmark)

    Andresen, Lars; Hansen, Karen Aagaard; Jensen, Helle

    2009-01-01

    We found that propionic acid secreted from propionibacteria induces expression of the NKG2D ligands MICA/B on activated T lymphocytes and different cancer cells, without affecting MICA/B expression on resting peripheral blood cells. Growth supernatant from propionibacteria or propionate alone could...... activity. Other short-chain fatty acids such as lactate, acetate, and butyrate could also induce MICA/B expression. We observed a striking difference in the molecular signaling pathways that regulate MICA/B. A functional glycolytic pathway was essential for MICA/B expression after exposure to propionate...... that propionate, produced either by bacteria or during cellular metabolism, has significant immunoregulatory function and may be cancer prophylactic....

  20. Ligand-induced fate of embryonic species in the shape-controlled synthesis of rhodium nanoparticles.

    Science.gov (United States)

    Biacchi, Adam J; Schaak, Raymond E

    2015-02-24

    The shapes of noble metal nanoparticles directly impact their properties and applications, including in catalysis and plasmonics, and it is therefore important to understand how multiple distinct morphologies can be controllably synthesized. Solution routes offer powerful capabilities for shape-controlled nanoparticle synthesis, but the earliest stages of the reaction are difficult to interrogate experimentally and much remains unknown about how metal nanoparticle morphologies emerge and evolve. Here, we use a well-established polyol process to synthesize uniform rhodium nanoparticle cubes, icosahedra, and triangular plates using bromide, trifluoroacetate, and chloride ligands, respectively. In all of these systems, we identified rhodium clusters with diameters of 1-2 nm that form early in the reactions. The colloidally stable metal cluster intermediates served as a stock solution of embryonic species that could be transformed predictably into each type of nanoparticle morphology. The anionic ligands that were added to the embryonic species determined their eventual fate, e.g., the morphologies into which they would ultimately evolve. Extensive high-resolution transmission electron microscopy experiments revealed that the growth pathway-monomer addition, coalescence, or a combination of the two-was different for each of the morphologies, and was likely controlled by the interactions of each specific anionic adsorbate with the embryonic species. Similar phenomena were observed for related palladium and platinum nanoparticle systems. These studies provide important insights into how noble metal nanoparticles nucleate, the pathways by which they grow into several distinct morphologies, and the imperative role of the anonic ligand in controlling which route predominates in a particular system.

  1. Fenofibrate, a peroxisome proliferator-activated receptor α ligand, prevents abnormal liver function induced by a fasting–refeeding process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon No; Dutta, Raghbendra Kumar; Kim, Seul-Gi; Lim, Jae-Young; Kim, Se-Jin; Choe, Seong-Kyu [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Yoo, Kyeong-Won [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Immune-network Pioneer Research Center, Department of Biochemistry, College of Medicine, Dong-A University, Busan (Korea, Republic of); Song, Seung Ryel [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Park, Do-Sim [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Department of Laboratory of Medicine, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); So, Hong-Seob [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of); Park, Raekil, E-mail: rkpark@wku.ac.kr [Center for Metabolic Function Regulation, and Department of Microbiology, School of Medicine, Wonkwang University, Iksan (Korea, Republic of)

    2013-12-06

    Highlights: •A fasting–refeeding high fat diet (HDF) model mimics irregular eating habit. •A fasting–refeeding HFD induces liver ballooning injury. •A fasting–refeeding HDF process elicits hepatic triglyceride accumulation. •Fenofibrate, PPARα ligand, prevents liver damage induced by refeeding HFD. -- Abstract: Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, is an anti-hyperlipidemic agent that has been widely used in the treatment of dyslipidemia. In this study, we examined the effect of fenofibrate on liver damage caused by refeeding a high-fat diet (HFD) in mice after 24 h fasting. Here, we showed that refeeding HFD after fasting causes liver damage in mice determined by liver morphology and liver cell death. A detailed analysis revealed that hepatic lipid droplet formation is enhanced and triglyceride levels in liver are increased by refeeding HFD after starvation for 24 h. Also, NF-κB is activated and consequently induces the expression of TNF-α, IL1-β, COX-2, and NOS2. However, treating with fenofibrate attenuates the liver damage and triglyceride accumulation caused by the fasting–refeeding HFD process. Fenofibrate reduces the expression of NF-κB target genes but induces genes for peroxisomal fatty acid oxidation, peroxisome biogenesis and mitochondrial fatty acid oxidation. These results strongly suggest that the treatment of fenofibrate ameliorates the liver damage induced by fasting–refeeding HFD, possibly through the activation of fatty acid oxidation.

  2. Thrombopoietin, c-Mpl ligand, induces tyrosine phosphorylation of Tyk2, JAK2, and STAT3, and enhances agonists-induced aggregation in platelets in vitro.

    Science.gov (United States)

    Ezumi, Y; Takayama, H; Okuma, M

    1995-10-23

    We investigated in vitro effects of recombinant human thrombopoietin (TPO), or c-Mpl ligand, on human platelets. TPO induced rapid dose-dependent tyrosine phosphorylation of several proteins. We identified Janus tyrosine kinases, Tyk2 and JAK2, and a member of STAT (signal transducers and activators of transcription) family, STAT3, as the tyrosine-phosphorylated proteins in response to TPO. TPO by itself did not cause platelet aggregation and shape change, but augmented ADP-induced aggregation in a dose-dependent manner. Acetylsalicylic acid inhibited the secondary aggregation enhanced by TPO, but not the TPO-induced potentiation of the primary aggregation. TPO modulates platelet activation possibly through protein-tyrosine phosphorylation.

  3. Dimeric Arrangement of the Parathyroid Hormone Receptor and a Structural Mechanism for Ligand-induced Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Pioszak, Augen A.; Harikumar, Kaleeckal G.; Parker, Naomi R.; Miller, Laurence J.; Xu, H. Eric (Van Andel); (Mayo)

    2010-06-25

    The parathyroid hormone receptor (PTH1R) is a class B G protein-coupled receptor that is activated by parathyroid hormone (PTH) and PTH-related protein (PTHrP). Little is known about the oligomeric state of the receptor and its regulation by hormone. The crystal structure of the ligand-free PTH1R extracellular domain (ECD) reveals an unexpected dimer in which the C-terminal segment of both ECD protomers forms an {alpha}-helix that mimics PTH/PTHrP by occupying the peptide binding groove of the opposing protomer. ECD-mediated oligomerization of intact PTH1R was confirmed in living cells by bioluminescence and fluorescence resonance energy transfer experiments. As predicted by the structure, PTH binding disrupted receptor oligomerization. A receptor rendered monomeric by mutations in the ECD retained wild-type PTH binding and cAMP signaling ability. Our results are consistent with the hypothesis that PTH1R forms constitutive dimers that are dissociated by ligand binding and that monomeric PTH1R is capable of activating G protein.

  4. Electrostatically induced recruitment of membrane peptides into clusters requires ligand binding at both interfaces.

    Directory of Open Access Journals (Sweden)

    Yuri N Antonenko

    Full Text Available Protein recruitment to specific membrane locations may be governed or facilitated by electrostatic attraction, which originates from a multivalent ligand. Here we explored the energetics of a model system in which this simple electrostatic recruitment mechanism failed. That is, basic poly-L-lysine binding to one leaflet of a planar lipid bilayer did not recruit the triply-charged peptide (O-Pyromellitylgramicidin. Clustering was only observed in cases where PLL was bound to both channel ends. Clustering was indicated (i by the decreased diffusional PLL mobility D(PLL and (ii by an increased lifetime τ(PLL of the clustered channels. In contrast, if PLL was bound to only one leaflet, neither D(PLL nor τ(P changed. Simple calculations suggest that electrostatic repulsion of the unbound ends prevented neighboring OPg dimers from approaching each other. We believe that a similar mechanism may also operate in cell signaling and that it may e.g. contribute to the controversial results obtained for the ligand driven dimerization of G protein-coupled receptors.

  5. Single-chain self-folding of synthetic polymers induced by metal-ligand complexation.

    Science.gov (United States)

    Willenbacher, Johannes; Altintas, Ozcan; Roesky, Peter W; Barner-Kowollik, Christopher

    2014-01-01

    The controlled folding of a single polymer chain is for the first time realized by metal- complexation. α,ω-Bromine functional linear polymers are prepared via activators regenerated by electron transfer (ARGET) ATRP (M¯n,SEC = 5900 g mol(-1) , Đ = 1.07 and 12 000 g mol(-1) , Đ = 1.06) and the end groups of the polymers are subsequently converted to azide functionalities. A copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction is carried out in the presence of a novel triphenylphosphine ligand and the polymers to afford homotelechelic bis-triphenylphosphine polymeric-macroligands (MLs) (M¯n,SEC = 6600 g mol(-1) , Đ = 1.07, and 12 800 g mol(-1) , Đ = 1.06). Single-chain metal complexes (SCMCs) are formed in the presence of Pd(II) ions in highly diluted solution at ambient temperature. The results derived via (1) H and (31) P{(1) H} NMR experiments, SEC, and DLS unambiguously evidence the efficient formation of SCMCs via metal ligand complexation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Different Concentrations of FGF Ligands, FGF2 or FGF8 Determine Distinct States of WNT-Induced Presomitic Mesoderm.

    Science.gov (United States)

    Sudheer, Smita; Liu, Jinhua; Marks, Matthias; Koch, Frederic; Anurin, Anna; Scholze, Manuela; Senft, Anna Dorothea; Wittler, Lars; Macura, Karol; Grote, Phillip; Herrmann, Bernhard G

    2016-07-01

    Presomitic mesoderm (PSM) cells are the precursors of the somites, which flank both sides of the neural tube and give rise to the musculo-skeletal system shaping the vertebrate body. WNT and FGF signaling control the formation of both the PSM and the somites and show a graded distribution with highest levels in the posterior PSM. We have used reporters for the mesoderm/PSM control genes T, Tbx6, and Msgn1 to investigate the differentiation of mouse ESCs from the naïve state via EpiSCs to PSM cells. Here we show that the activation of WNT signaling by CHIR99021 (CH) in combination with FGF ligand induces embryo-like PSM at high efficiency. By varying the FGF ligand concentration, the state of PSM cells formed can be altered. High FGF concentration supports posterior PSM formation, whereas low FGF generates anterior/differentiating PSM, in line with in vivo data. Furthermore, the level of Msgn1 expression depends on the FGF ligand concentration. We also show that Activin/Nodal signaling inhibits CH-mediated PSM induction in EpiSCs, without affecting T-expression. Inversely, Activin/Nodal inhibition enhances PSM induction by WNT/high FGF signaling. The ability to generate PSM cells of either posterior or anterior PSM identity with high efficiency in vitro will promote the investigation of the gene regulatory networks controlling the formation of nascent PSM cells and their switch to differentiating/somitic paraxial mesoderm. Stem Cells 2016;34:1790-1800.

  7. Ligands of Peroxisome Proliferator-activated Receptor Inhibit Homocysteineinduced DNA Methylation of Inducible Nitric Oxide Synthase Gene

    Institute of Scientific and Technical Information of China (English)

    Yideng JIANG; Jianzhong ZHANG; Jiantuan XIONG; Jun CAO; Guizhong LI; Shuren WANG

    2007-01-01

    Homocysteine (Hcy) is a risk factor for atherosclerosis. It is generally accepted that inducible nitric oxide synthase (iNOS) is a key enzyme in the regulation of vascular disease. The aim of the present study is to investigate the effects of peroxisome proliferator-activated receptor ligands on iNOS in the presence of Hcy in human monocytes. Foam cells, induced by oxidize low density lipoprotein (ox-LDL) and phorbol myristate acetate (PMA) in the presence of different concentrations of Hcy, clofibrate and pioglitazone in human monocytes for 4 d, were examined by oil red O staining. The activity of iNOS was detected by real-time quantitative reverse transcription-polymerase chain reaction and Western blot analysis. The capability of DNA methylation was measured by assaying endogenous C5 DNA methyltransferase (C5MTase)activity, and the iNOS promoter methylation level was determined by quantitative MethyLight assays. The results indicated that Hcy increased the activity of C5MTase and the level of iNOS gene DNA methylation,resulting in a decrease of iNOS expression. Clofibrate and pioglitazone could antagonize the Hcy effect on iNOS expression through DNA methylation, resulting in attenuation of iNOS transcription. These findings suggested that Hcy decreased the expression of iNOS by elevating iNOS DNA methylation levels, which can repress the transcription of some genes. Peroxisome proliferator-activated receptor α/γ ligands can down-regulate iNOS DNA methylation, and could be useful for preventing Hcy-induced atherosclerosis by repressing iNOS expression.

  8. Nasal immunization with M cell-targeting ligand-conjugated ApxIIA toxin fragment induces protective immunity against Actinobacillus pleuropneumoniae infection in a murine model.

    Science.gov (United States)

    Park, Jisang; Seo, Ki-Weon; Kim, Sae-Hae; Lee, Ha-Yan; Kim, Bumseok; Lim, Chae Woong; Kim, Jin-Hee; Yoo, Han Sang; Jang, Yong-Suk

    2015-05-15

    Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia and severe economic loss in the swine industry has been caused by the infection. Therefore, the development of an effective vaccine against the bacteria is necessary. ApxII toxin, among several virulence factors expressed by the bacteria, is considered to be a promising vaccine candidate because ApxII toxin not only accompanies cytotoxic and hemolytic activities, but is also expressed in all 15 serotypes of bacteria except serotypes 10 and 14. In this study, we identified the peptide ligand capable of targeting the ligand-conjugated ApxIIA #5 fragment antigen to nasopharynx-associated lymphoid tissue. It was found that nasal immunization with ligand-conjugated ApxIIA #5 induced efficient mucosal and systemic immune responses measured at the levels of antigen-specific antibodies, cytokine-secreting cells after antigen exposure, and antigen-specific lymphocyte proliferation. More importantly, the nasal immunization induced protective immunity against nasal challenge infection of the bacteria, which was confirmed by histopathological studies and bacterial clearance after challenge infection. Collectively, we confirmed that the ligand capable of targeting the ligand-conjugated antigen to nasopharynx-associated lymphoid tissue can be used as an effective nasal vaccine adjuvant to induce protective immunity against A. pleuropneumoniae infection. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. CD40 ligand induced cytotoxicity in carcinoma cells is enhanced by inhibition of metalloproteinase cleavage and delivery via a conditionally-replicating adenovirus

    Directory of Open Access Journals (Sweden)

    Young Lawrence S

    2010-03-01

    Full Text Available Abstract Background CD40 and its ligand (CD40L play a critical role in co-ordinating immune responses. CD40 is also expressed in lymphoid malignancies and a number of carcinomas. In carcinoma cells the physiological outcome of CD40 ligation depends on the level of receptor engagement with low levels promoting cell survival and high levels inducing cell death. The most profound induction of cell death in carcinoma cells is induced by membrane-bound rather than recombinant soluble CD40L, but like other TNF family ligands, it is cleaved from the membrane by matrix metalloproteinases. Results We have generated a replication-deficient adenovirus expressing a mutant CD40L that is resistant to metalloproteinase cleavage such that ligand expression is retained at the cell membrane. Here we show that the mutated, cleavage-resistant form of CD40L is a more potent inducer of apoptosis than wild-type ligand in CD40-positive carcinoma cell lines. Since transgene expression via replication-deficient adenovirus vectors in vivo is low, we have also engineered a conditionally replicating E1A-CR2 deleted adenovirus to express mutant CD40L, resulting in significant amplification of ligand expression and consequent enhancement of its therapeutic effect. Conclusions Combined with numerous studies demonstrating its immunotherapeutic potential, these data provide a strong rationale for the exploitation of the CD40-CD40L pathway for the treatment of solid tumours.

  10. Hispolon from Phellinus linteus induces apoptosis and sensitizes human cancer cells to the tumor necrosis factor-related apoptosis-inducing ligand through upregulation of death receptors.

    Science.gov (United States)

    Kim, Ji-Hun; Kim, Yu Chul; Park, Byoungduck

    2016-02-01

    The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent anticancer agent possessing the ability to induce apoptosis in various cancer cells but not in non‑malignant cells. However, certain type of cancer cells are resistant to TRAIL‑induced apoptosis and some acquire resistance after the first treatment. So development of an agent that can reduce or avoid resistance in TRAIL‑induced apoptosis has garnered significant attention. The present study evaluated the anticancer potential of hispolon in TRAIL‑induced apoptosis and indicated hispolon can sensitize cancer cells to TRAIL. As the mechanism of action was examined, hispolon was found to activate caspase‑3, caspase‑8 and caspase‑9, while downregulating the expression of cell survival proteins such as cFLIP, Bcl‑2 and Bcl‑xL and upregulating the expression of Bax and truncated Bid. We also found hispolon induced death receptors in a non‑cell type‑specific manner. Upregulation of death receptors by hispolon was found to be p53-independent but linked to the induction of CAAT enhancer binding protein homologous protein (CHOP). Overall, hispolon was demonstrated to potentiate the apoptotic effects of TRAIL through downregulation of anti‑apoptotic proteins and upregulation of death receptors linked with CHOP and pERK elevation.

  11. CR4056, a new analgesic I2 ligand, is highly effective against bortezomib-induced painful neuropathy in rats

    Directory of Open Access Journals (Sweden)

    Meregalli C

    2012-06-01

    Full Text Available Cristina Meregalli,1 Cecilia Ceresa,1 Annalisa Canta,1 Valentina Alda Carozzi,1 Alessia Chiorazzi,1 Barbara Sala,1 Norberto Oggioni,1 Marco Lanza,2 Ornella Letar,i2 Flora Ferrari,2 Federica Avezza,1 Paola Marmiroli,1 GianFranco Caselli,2 Guido Cavaletti11Department of Neuroscience and Biomedical Technologies, University of Milan-Bicocca, 2Pharmacology and Toxicology Department, Rottapharm | Madaus Research Center, Monza, ItalyAbstract: Although bortezomib (BTZ is the frontline treatment for multiple myeloma, its clinical use is limited by the occurrence of painful peripheral neuropathy, whose treatment is still an unmet clinical need. Previous studies have shown chronic BTZ administration (0.20 mg/kg intravenously three times a week for 8 weeks to female Wistar rats induced a peripheral neuropathy similar to that observed in humans. In this animal model of BTZ-induced neurotoxicity, the present authors evaluated the efficacy of CR4056, a novel I2 ligand endowed with a remarkable efficacy in several animal pain models. CR4056 was administered in a wide range of doses (0.6–60 mg/kg by gavage every day for 2–3 weeks in comparison with buprenorphine (Bupre (28.8 µg/kg subcutaneously every day for 2 weeks and gabapentin (Gaba (100 mg/kg by gavage every day for 3 weeks. Chronic administration of BTZ reduced nerve conduction velocity and induced allodynia. CR4056, Bupre, or Gaba did not affect the impaired nerve conduction velocity. Conversely, CR4056 dose-dependently reversed BTZ-induced allodynia (minimum effective dose 0.6 mg/kg. The optimal dose found, 6 mg/kg, provided a constant pain relief throughout the treatment period and without rebound after suspension, being effective when coadministered with BTZ, starting before or after allodynia was established, or when administered alone after BTZ cessation. A certain degree of tolerance was seen after 7 days of administration, but only at the highest doses (20 and 60 mg/kg. Bupre was effective

  12. Pioglitazone, a specific ligand of peroxisome proliferator-activated receptor-gamma, protects pancreas against acute cerulein-induced pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Peter C Konturek; Artur Dembinski; Zygmunt Warzecha; Grzegorz Burnat; Piotr Ceranowicz; Eckhart G Hahn; Marcin Dembinski; Romana Tomaszewska; Stanislaw J Konturek

    2005-01-01

    AIM: To determine the effect of pioglitazone, a specific peroxisome proliferator-activated receptor-γ (PPARγ)ligand, on the development of acute pancreatitis (AP) and on the expression of heat shock protein 70 (HSP70) in the pancreas.METHODS: AP was induced in rats by subcutaneous infusion of cerulein for 5 h. Pancreatic blood flow was measured by laser Doppler flowmetry. Plasma lipase activity, interleukin-1β (IL-1β) and IL-10 were determined.Pancreatic weight and histology were evaluated and pancreatic DNA synthesis and blood flow as well as pancreatic mRNA for IL-1β and HSP70 were assessed in rats treated with pioglitazone alone or in combination with cerulein.RESULTS: Pioglitazone administered (10-100 mg/kg I.g.)30 min before cerulein, attenuated dose-dependently the pancreatic tissue damage in cerulein-induced pancreatitis (CIP) as demonstrated by the improvement of pancreatic histology, reduction in plasma lipase activity,plasma concentration of pro-inflammatory IL-1β and its gene expression in the pancreas and attenuation of the pancreatitis-evoked fall in pancreatic blood flow. CIP increased pancreatic HSP70 mRNA and protein expression in the pancreas and this effect was enhanced by pioglitazone treatment.CONCLUSION: Pioglitazone attenuates CIP and the beneficial effect of this pioglitazone is multifactorial probably due to its anti-inflammatory activities, to the suppression of IL-1β and to the overexpression of HSP70.PPARγ ligands could represent a new therapeutic option in the treatment of AP.

  13. Pioglitazone, a specific ligand of peroxisome proliferator-activated receptor-gamma, protects pancreas against acute cerulein-induced pancreatitis

    Science.gov (United States)

    Konturek, Peter C; Dembinski, Artur; Warzecha, Zygmunt; Burnat, Grzegorz; Ceranowicz, Piotr; Hahn, Eckhart G; Dembinski, Marcin; Tomaszewska, Romana; Konturek, Stanislaw J

    2005-01-01

    AIM: To determine the effect of pioglitazone, a specific peroxisome proliferator-activated receptor-γ (PPARγ) ligand, on the development of acute pancreatitis (AP) and on the expression of heat shock protein 70 (HSP70) in the pancreas. METHODS: AP was induced in rats by subcutaneous infusion of cerulein for 5 h. Pancreatic blood flow was measured by laser Doppler flowmetry. Plasma lipase activity, interleukin-1β (IL-1β) and IL-10 were determined. Pancreatic weight and histology were evaluated and pancreatic DNA synthesis and blood flow as well as pancreatic mRNA for IL-1β and HSP70 were assessed in rats treated with pioglitazone alone or in combination with cerulein. RESULTS: Pioglitazone administered (10-100 mg/kg i.g.) 30 min before cerulein, attenuated dose-dependently the pancreatic tissue damage in cerulein-induced pancreatitis (CIP) as demonstrated by the improvement of pancreatic histology, reduction in plasma lipase activity, plasma concentration of pro-inflammatory IL-1β and its gene expression in the pancreas and attenuation of the pancreatitis-evoked fall in pancreatic blood flow. CIP increased pancreatic HSP70 mRNA and protein expression in the pancreas and this effect was enhanced by pioglitazone treatment. CONCLUSION: Pioglitazone attenuates CIP and the beneficial effect of this pioglitazone is multifactorial probably due to its anti-inflammatory activities, to the suppression of IL-1β and to the overexpression of HSP70. PPARγ ligands could represent a new therapeutic option in the treatment of AP. PMID:16419161

  14. Interferon (IFN)-beta induces apoptotic cell death in DHL-4 diffuse large B cell lymphoma cells through tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).

    Science.gov (United States)

    Oehadian, Amaylia; Koide, Naoki; Mu, Mya Mya; Hassan, Ferdaus; Islam, Shamima; Yoshida, Tomoaki; Yokochi, Takashi

    2005-07-08

    The effect of interferon (IFN)-alpha, beta and gamma on the growth of DHL-4 diffuse large B cell lymphoma cells was studied. IFN-beta significantly inhibited the cell growth, and the effect was stronger than that of IFN-alpha. IFN-gamma did not inhibit the cell growth because of lack of IFN-gamma receptors. IFN-beta caused apoptotic cell death which was accompanied by DNA fragmentation, caspase 3 activation and annexin V binding. IFN-beta lead to the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mRNA. Anti-TRAIL antibody significantly prevented IFN-beta-induced apoptosis. It was suggested that IFN-beta might cause apoptosis in DHL-4 cells through TRAIL.

  15. Cancer immunoediting by GITR (glucocorticoid-induced TNF-related protein) ligand in humans: NK cell/tumor cell interactions.

    Science.gov (United States)

    Baltz, Katrin M; Krusch, Matthias; Bringmann, Anita; Brossart, Peter; Mayer, Frank; Kloss, Mercedes; Baessler, Tina; Kumbier, Ingrid; Peterfi, Andrea; Kupka, Susan; Kroeber, Stefan; Menzel, Dagmar; Radsak, Markus P; Rammensee, Hans-Georg; Salih, Helmut R

    2007-08-01

    Glucocorticoid-induced TNF-related protein (GITR) has been shown to stimulate T cell-mediated antitumor immunity in mice. However, the functional relevance of GITR and its ligand (GITRL) for non-T cells has yet to be fully explored. In addition, recent evidence suggests that GITR plays different roles in mice and humans. We studied the role of GITR-GITRL interaction in human tumor immunology and report for the first time that primary gastrointestinal cancers and tumor cell lines of different histological origin express substantial levels of GITRL. Signaling through GITRL down-regulated the expression of the immunostimulatory molecules CD40 and CD54 and the adhesion molecule EpCAM, and induced production of the immunosuppressive cytokine TGF-beta by tumor cells. On NK cells, GITR is constitutively expressed and up-regulated following activation. Blocking GITR-GITRL interaction in cocultures of tumor cells and NK cells substantially increased cytotoxicity and IFN-gamma production of NK cells demonstrating that constitutive expression of GITRL by tumor cells diminishes NK cell antitumor immunity. GITRL-Ig fusion protein or cell surface-expressed GITRL did not induce apoptosis in NK cells, but diminished nuclear localized c-Rel and RelB, indicating that GITR might negatively modulate NK cell NF-kappaB activity. Taken together, our data indicate that tumor-expressed GITRL mediates immunosubversion in humans.

  16. Tumor Necrosis Factor-related Apoptosis Ligand Induces Apoptosis in Prostate Cancer PC-3M Cell Line

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhohui; WANG Huafang; GU Longjie; YE Zhewei; XIAO Yajun

    2005-01-01

    To study the effect of tumor necrosis factor-related apoptosis inducing ligand (TRAIL)on PC-3M cell line, PC-3M cell line was incubated with gradient concentrations of TRAIL for 4-24h. Annixin-Ⅴ fluorescence staining and TUNEL method were employed to detect the apoptosis of PC-3M cells. The morphology of apoptotic PC-3M cells was observed by electron microscopy. The relationship between TRAIL concentrations and the percentage of apoptotic cells was evaluated by flow cytometry. The proliferation inhibitory ratio was calculated by using MTT colorimetry. Our results showed that apoptosis of PC-3M cells could be induced by treatment with TRAIL for at most 4 h. The results of flow cytometry and MTT colorimetry demonstrated a time- and concentration-dependent relationship between cell apoptosis rate and TRAIL concentration. It is concluded that apoptosis of PC-3M cells can be induced by TRAIL. Because of the selective killing effect of TRAIL on tumor ceils, it may become a potential alternative for the treatment of advanced prostate cancer.

  17. TNF-related apoptosis-inducing ligand (TRAIL) exerts therapeutic efficacy for the treatment of pneumococcal pneumonia in mice.

    Science.gov (United States)

    Steinwede, Kathrin; Henken, Stefanie; Bohling, Jennifer; Maus, Regina; Ueberberg, Bianca; Brumshagen, Christina; Brincks, Erik L; Griffith, Thomas S; Welte, Tobias; Maus, Ulrich A

    2012-10-22

    Apoptotic death of alveolar macrophages observed during lung infection with Streptococcus pneumoniae is thought to limit overwhelming lung inflammation in response to bacterial challenge. However, the underlying apoptotic death mechanism has not been defined. Here, we examined the role of the TNF superfamily member TNF-related apoptosis-inducing ligand (TRAIL) in S. pneumoniae-induced macrophage apoptosis, and investigated the potential benefit of TRAIL-based therapy during pneumococcal pneumonia in mice. Compared with WT mice, Trail(-/-) mice demonstrated significantly decreased lung bacterial clearance and survival in response to S. pneumoniae, which was accompanied by significantly reduced apoptosis and caspase 3 cleavage but rather increased necrosis in alveolar macrophages. In WT mice, neutrophils were identified as a major source of intraalveolar released TRAIL, and their depletion led to a shift from apoptosis toward necrosis as the dominant mechanism of alveolar macrophage cell death in pneumococcal pneumonia. Therapeutic application of TRAIL or agonistic anti-DR5 mAb (MD5-1) dramatically improved survival of S. pneumoniae-infected WT mice. Most importantly, neutropenic mice lacking neutrophil-derived TRAIL were protected from lethal pneumonia by MD5-1 therapy. We have identified a previously unrecognized mechanism by which neutrophil-derived TRAIL induces apoptosis of DR5-expressing macrophages, thus promoting early bacterial killing in pneumococcal pneumonia. TRAIL-based therapy in neutropenic hosts may represent a novel antibacterial treatment option.

  18. Calreticulin Binds to Fas Ligand and Inhibits Neuronal Cell Apoptosis Induced by Ischemia-Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Beilei Chen

    2015-01-01

    Full Text Available Background. Calreticulin (CRT can bind to Fas ligand (FasL and inhibit Fas/FasL-mediated apoptosis of Jurkat T cells. However, its effect on neuronal cell apoptosis has not been investigated. Purpose. We aimed to evaluate the neuroprotective effect of CRT following ischemia-reperfusion injury (IRI. Methods. Mice underwent middle cerebral artery occlusion (MCAO and SH-SY5Y cells subjected to oxygen glucose deprivation (OGD were used as models for IRI. The CRT protein level was detected by Western blotting, and mRNA expression of CRT, caspase-3, and caspase-8 was measured by real-time PCR. Immunofluorescence was used to assess the localization of CRT and FasL. The interaction of CRT with FasL was verified by coimmunoprecipitation. SH-SY5Y cell viability was determined by MTT assay, and cell apoptosis was assessed by flow cytometry. The measurement of caspase-8 and caspase-3 activity was carried out using caspase activity assay kits. Results. After IRI, CRT was upregulated on the neuron surface and bound to FasL, leading to increased viability of OGD-exposed SH-SY5Y cells and decreased activity of caspase-8 and caspase-3. Conclusions. This study for the first time revealed that increased CRT inhibited Fas/FasL-mediated neuronal cell apoptosis during the early stage of ischemic stroke, suggesting it to be a potential protector activated soon after IRI.

  19. Expression of tumour necrosis factor-related apoptosis-inducing ligand death receptors in sporadic and hereditary colorectal tumours : Potential targets for apoptosis induction

    NARCIS (Netherlands)

    Koornstra, JJ; Jalving, M; Rijcken, FEM; Westra, Jantine; Zwart, N; Hollema, H; de Vries, EGE; Hofstra, RWM; Plukker, JTM; de Jong, S; Kleibeuker, JH

    2005-01-01

    Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and antibodies against TRAIL receptors death receptor 4 (DR4) and death receptor 5 (DR5) are under investigation for cancer therapy. To study the potential application of these agents, the expression of DR4 and DR5 were studied immunoh

  20. Activation Induces Structural Changes in the Liganded Angiotensin II Type 1 Receptor*

    Science.gov (United States)

    Clément, Martin; Cabana, Jérôme; Holleran, Brian J.; Leduc, Richard; Guillemette, Gaétan; Lavigne, Pierre; Escher, Emanuel

    2009-01-01

    The octapeptide hormone angiotensin II (AngII) binds to and activates the human angiotensin II type 1 receptor (hAT1) of the G protein-coupled receptor class A family. Several activation mechanisms have been proposed for this family, but they have not yet been experimentally validated. We previously used the methionine proximity assay to show that 11 residues in transmembrane domain (TMD) III, VI, and VII of the hAT1 receptor reside in close proximity to the C-terminal residue of AngII. With the exception of a single change in TMD VI, the same contacts are present on N111G-hAT1, a constitutively active mutant; this N111G-hAT1 is a model for the active form of the receptor. In this study, two series of 53 individual methionine mutations were constructed in TMD I, II, IV, and V on both receptor forms. The mutants were photolabeled with a neutral antagonist, 125I-[Sar1,p-benzoyl-l-Phe8]AngII, and the resulting complexes were digested with cyanogen bromide. Although no new contacts were found for the hAT1 mutants, two were found in the constitutively active mutants, Phe-77 in TMD II and Asn-200 in TMD V. To our knowledge, this is the first time that a direct ligand contact with TMD II and TMD V has been reported. These contact point differences were used to identify the structural changes between the WT-hAT1 and N111G-hAT1 complexes through homology-based modeling and restrained molecular dynamics. The model generated revealed an important structural rearrangement of several TMDs from the basal to the activated form in the WT-hAT1 receptor. PMID:19635801

  1. The serotonin transporter: Examination of the changes in transporter affinity induced by ligand binding

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, C.J.

    1989-01-01

    The plasmalemmal serotonin transporter uses transmembrane gradients of Na{sup +}, Cl{sup {minus}} and K{sup +} to accumulate serotonin within blood platelets. Transport is competitively inhibited by the antidepressant imipramine. Like serotonin transport, imipramine binding requires Na{sup +}. Unlike serotonin, however, imipramine does not appear to be transported. To gain insight into the mechanism of serotonin transport the author have analyzed the influences of Na{sup +} and Cl{sup {minus}}, the two ions cotransported with serotonin, on both serotonin transport and the interaction of imipramine and other antidepressant drugs with the plasmalemmal serotonin transporter of human platelets. Additionally, the author have synthesized, purified and characterized the binding of 2-iodoimipramine to the serotonin transporter. Finally, the author have conducted a preliminary study of the inhibition of serotonin transport and imipramine binding produced by dicyclohexylcarbodiimide. My results reveal many instances of positive heterotropic cooperativity in ligand binding to the serotonin transporter. Na{sup +} binding enhances the transporters affinity for imipramine and several other antidepressant drugs, and also increases the affinity for Cl{sup {minus}}. Cl{sup {minus}} enhances the transporters affinity for imipramine, as well as for Na{sup +}. At concentrations in the range of its K{sub M} for transport serotonin is a competitive inhibitor of imipramine binding. At much higher concentrations, however, serotonin also inhibits imipramines dissociation rate constant. This latter effect which is Na{sup +}-independent and species specific, is apparently produced by serotonin binding at a second, low affinity site on, or near, the transporter complex. Iodoimipramine competitively inhibit both ({sup 3}H)imipramine binding and ({sup 3}H)serotonin transport.

  2. Ginsenoside Rh2 induces ligand-independent Fas activation via lipid raft disruption

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Jae-Sung; Choo, Hyo-Jung [College of Life Sciences and Biotechnology, Korea University, 1, 5-ka, Anam-dong, Sungbuk-gu, Seoul 136-701 (Korea, Republic of); Cho, Bong-Rae [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of); Kim, Hwan-Myung [Department of Chemistry, Ajou University, Suwon, Kyunggi-Do 443-749 (Korea, Republic of); Kim, Yong-Nyun [Division of Specific Organs Center, National Cancer Center, Kyunggi-Do 411-769 (Korea, Republic of); Ham, Young-Mi, E-mail: ymham2@hanmail.net [College of Life Sciences and Biotechnology, Korea University, 1, 5-ka, Anam-dong, Sungbuk-gu, Seoul 136-701 (Korea, Republic of); Ko, Young-Gyu, E-mail: ygko@korea.ac.kr [College of Life Sciences and Biotechnology, Korea University, 1, 5-ka, Anam-dong, Sungbuk-gu, Seoul 136-701 (Korea, Republic of)

    2009-07-24

    Lipid rafts are plasma membrane platforms mediating signal transduction pathways for cellular proliferation, differentiation and apoptosis. Here, we show that membrane fluidity was increased in HeLa cells following treatment with ginsenoside Rh2 (Rh2), as determined by cell staining with carboxy-laurdan (C-laurdan), a two-photon dye designed for measuring membrane hydrophobicity. In the presence of Rh2, caveolin-1 appeared in non-raft fractions after sucrose gradient ultracentrifugation. In addition, caveolin-1 and GM1, lipid raft landmarkers, were internalized within cells after exposure to Rh2, indicating that Rh2 might disrupt lipid rafts. Since cholesterol overloading, which fortifies lipid rafts, prevented an increase in Rh2-induced membrane fluidity, caveolin-1 internalization and apoptosis, lipid rafts appear to be essential for Rh2-induced apoptosis. Moreover, Rh2-induced Fas oligomerization was abolished following cholesterol overloading, and Rh2-induced apoptosis was inhibited following treatment with siRNA for Fas. This result suggests that Rh2 is a novel lipid raft disruptor leading to Fas oligomerization and apoptosis.

  3. GABA(A)-benzodiazepine receptor complex ligands and stress-induced hyperthermia in singly housed mice.

    NARCIS (Netherlands)

    Olivier, B.; Bouwknecht, J.A.; Pattij, T.; Leahy, C.; Oorschot, R. van; Zethof, T.J.

    2002-01-01

    Stress-induced hyperthermia (SIH) in singly housed mice, in which the rectal temperature of a mouse is measured twice with a 10-min interval, enables to study the effects of a drug on the basal (T(1)) and on the stress-enhanced temperature (T(2)), 10 min later, using the rectal procedure as stressor

  4. The role of organic ligands in ferrous-induced photochemical degradation of 2,4-dichlorophenoxyacetic acid.

    Science.gov (United States)

    Kwan, C Y; Chu, W

    2007-04-01

    Recent studies have shown that hydrogen peroxide is generated in a ferrioxalate-induced photoreductive reaction, but information about the effect of organic ligands on the photochemical behaviour of ferrous species is limited. The degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) by a ferrous-catalyzed oxidation in the presence of various ligands such as formate, citrate, malelate, oxalate, and ethylenediaminetetra-acetic acid (EDTA) was studied. The experiments were conducted under either dark or irradiated (350n m) conditions. Forty-two percent and 34% of 2,4-D were removed by the Fe(2+)/oxalate/UV and Fe(2+)/citrate/UV processes, respectively, after 30 min of reaction and oxidative intermediates were obtained in both cases. The presence of hydroxylated intermediates suggests that 2,4-D may be attacked by hydroxyl radicals, which are the products of the photo-Fenton-like reaction. As such, hydrogen peroxide was produced by the photolysis of ferrous oxalate or ferrous citrate, referred to hereafter as photogenerated H(2)O(2). As expected, the total removal percentage of 2,4-D jumped to 97% when 1mM of hydrogen peroxide (so-called spiked H(2)O(2)) was externally added to the reaction vessel to initiate the Fe(2+)/oxalate/UV process. Therefore, the treatment of 2,4-D by the Fe(2+)/oxalate/H(2)O(2)/UV system can be operated in two steps: the photolysis of ferrous oxalate first, followed by adding the spiked H(2)O(2) sometime after the commencement of the reaction. A two-phase model has been developed to describe this tandem ferrous-catalyzed photooxidation, which would help to achieve the mineralization of 2,4-D.

  5. How reliable are pseudocontact shifts induced in proteins and ligands by mobile paramagnetic metal tags? A modelling study

    Energy Technology Data Exchange (ETDEWEB)

    Shishmarev, Dmitry; Otting, Gottfried, E-mail: gottfried.otting@anu.edu.au [Australian National University, Research School of Chemistry (Australia)

    2013-07-15

    The anisotropic component of the magnetic susceptibility tensor ({Delta}{chi} tensor) associated with various paramagnetic metal ions can induce pseudocontact shifts (PCSs) and residual dipolar couplings (RDCs) in proteins, yielding valuable restraints in structural studies. In particular, PCSs have successfully been used to study ligands that bind to proteins tagged with a paramagnetic metal ion, which is of great interest in fragment-based drug design. To create easy-to-interpret PCSs, the metal ion must be attached to the protein in a rigid manner. Most of the existing methods for site-specific attachment of a metal tag, however, result in tethers with residual flexibility. Here we present model calculations to quantify the extent, to which mobility of the metal-binding tag can compromise the quality of the {Delta}{chi} tensor that can be determined from the PCSs observed in the protein. Assuming that the protein can be approximated by a sphere and the tag is attached by a single tether, the results show that a single effective Increment {chi} tensor can describe the PCSs and RDCs of the protein spins very well even in the presence of substantial tag mobility, implying that PCSs of ligands in binding pockets of the protein can be predicted with similar accuracy. In contrast, the quality of the PCS prediction for nuclear spins positioned above the surface of the protein is significantly poorer, with implications for studies of protein-protein complexes. The simulations probed the sensitivity of the effective {Delta}{chi} tensor to different parameters, including length of the tether between protein and metal ion, protein size, type and amplitude of tag motion, tensor orientation relative to the protein and direction of tag motion. Tether length and amplitude of motion were identified as two key parameters. It is shown that the amplitude of tag motions cannot be quantified by simple comparisons of the effective {Delta}{chi} tensor with the alignment tensor

  6. Trapping conformational states along ligand-binding dynamics of peptide deformylase: the impact of induced fit on enzyme catalysis.

    Directory of Open Access Journals (Sweden)

    Sonia Fieulaine

    2011-05-01

    Full Text Available For several decades, molecular recognition has been considered one of the most fundamental processes in biochemistry. For enzymes, substrate binding is often coupled to conformational changes that alter the local environment of the active site to align the reactive groups for efficient catalysis and to reach the transition state. Adaptive substrate recognition is a well-known concept; however, it has been poorly characterized at a structural level because of its dynamic nature. Here, we provide a detailed mechanism for an induced-fit process at atomic resolution. We take advantage of a slow, tight binding inhibitor-enzyme system, actinonin-peptide deformylase. Crystal structures of the initial open state and final closed state were solved, as well as those of several intermediate mimics captured during the process. Ligand-induced reshaping of a hydrophobic pocket drives closure of the active site, which is finally "zipped up" by additional binding interactions. Together with biochemical analyses, these data allow a coherent reconstruction of the sequence of events leading from the encounter complex to the key-lock binding state of the enzyme. A "movie" that reconstructs this entire process can be further extrapolated to catalysis.

  7. Human dendritic cells mediate cellular apoptosis via tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).

    Science.gov (United States)

    Fanger, N A; Maliszewski, C R; Schooley, K; Griffith, T S

    1999-10-18

    TRAIL (TNF-related apoptosis-inducing ligand) is a member of the TNF family that induces apoptosis in a variety of cancer cells. In this study, we demonstrate that human CD11c(+) blood dendritic cells (DCs) express TRAIL after stimulation with either interferon (IFN)-gamma or -alpha and acquire the ability to kill TRAIL-sensitive tumor cell targets but not TRAIL-resistant tumor cells or normal cell types. The DC-mediated apoptosis was TRAIL specific, as soluble TRAIL receptor blocked target cell death. Moreover, IFN-stimulated interleukin (IL)-3 receptor (R)alpha(+) blood precursor (pre-)DCs displayed minimal cytotoxicity toward the same target cells, demonstrating a clear functional difference between the CD11c(+) DC and IL-3Ralpha(+) pre-DC subsets. These results indicate that TRAIL may serve as an innate effector molecule on CD11c(+) DCs for the elimination of spontaneously arising tumor cells and suggest a means by which TRAIL-expressing DCs may regulate or eliminate T cells responding to antigen presented by the DCs.

  8. A copper complex supported by an N2S-tridentate ligand inducing efficient heterolytic O-O bond cleavage of alkylhydroperoxide.

    Science.gov (United States)

    Tano, Tetsuro; Mieda, Kaoru; Sugimoto, Hideki; Ogura, Takashi; Itoh, Shinobu

    2014-03-28

    We have recently reported a copper(II)-superoxide complex supported by an N3-tridentate ligand (L(N3)), which exhibits a similar structure and reactivity to those of a putative reactive intermediate involved in the catalytic reactions of copper monooxygenases such as peptidylglycine α-hydroxylating monooxygenase (PHM) and dopamine β-monooxygenase (DβM). In this study, we have synthesised and characterised copper complexes supported by a related sulphur-containing ligand (L(N2S)) to get insight into the notable electronic effect of the sulphur donor atom in the reaction with cumene hydroperoxide, inducing efficient heterolytic O-O bond cleavage.

  9. PPARγ ligands decrease hydrostatic pressure-induced platelet aggregation and proinflammatory activity.

    Directory of Open Access Journals (Sweden)

    Fang Rao

    Full Text Available Hypertension is known to be associated with platelet overactivity, but the direct effects of hydrostatic pressure on platelet function remain unclear. The present study sought to investigate whether elevated hydrostatic pressure is responsible for platelet activation and to address the potential role of peroxisome proliferator-activated receptor-γ (PPARγ. We observed that hypertensive patients had significantly higher platelet volume and rate of ADP-induced platelets aggregation compared to the controls. In vitro, Primary human platelets were cultured under standard (0 mmHg or increased (120, 180, 240 mmHg hydrostatic pressure for 18 h. Exposure to elevated pressure was associated with morphological changes in platelets. Platelet aggregation and PAC-1 (the active confirmation of GPIIb/IIIa binding were increased, CD40L was translocated from cytoplasm to the surface of platelet and soluble CD40L (sCD40L was released into the medium in response to elevated hydrostatic pressure (180 and 240 mmHg. The PPARγ activity was up-regulated as the pressure was increased from 120 mmHg to 180 mmHg. Pressure-induced platelet aggregation, PAC-1 binding, and translocation and release of CD40L were all attenuated by the PPARγ agonist Thiazolidinediones (TZDs. These results demonstrate that platelet activation and aggregation are increased by exposure to elevated pressure and that PPARγ may modulate platelet activation induced by high hydrostatic pressure.

  10. Sensitivity to Flg22 Is Modulated by Ligand-Induced Degradation and de Novo Synthesis of the Endogenous Flagellin-Receptor FLAGELLIN-SENSING2[W][OPEN

    Science.gov (United States)

    Smith, John M.; Salamango, Daniel J.; Leslie, Michelle E.; Collins, Carina A.; Heese, Antje

    2014-01-01

    FLAGELLIN-SENSING2 (FLS2) is the plant cell surface receptor that perceives bacterial flagellin or flg22 peptide, initiates flg22-signaling responses, and contributes to bacterial growth restriction. Flg22 elicitation also leads to ligand-induced endocytosis and degradation of FLS2 within 1 h. Why plant cells remove this receptor precisely at the time during which its function is required remains mainly unknown. Here, we assessed in planta flg22-signaling competency in the context of ligand-induced degradation of endogenous FLS2 and chemical interference known to impede flg22-dependent internalization of FLS2 into endocytic vesicles. Within 1 h after an initial flg22 treatment, Arabidopsis (Arabidopsis thaliana) leaf tissue was unable to reelicit flg22 signaling in a ligand-, time-, and dose-dependent manner. These results indicate that flg22-induced degradation of endogenous FLS2 may serve to desensitize cells to the same stimulus (homologous desensitization), likely to prevent continuous signal output upon repetitive flg22 stimulation. In addition to impeding ligand-induced FLS2 degradation, pretreatment with the vesicular trafficking inhibitors Wortmannin or Tyrphostin A23 impaired flg22-elicited reactive oxygen species production that was partially independent of BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1. Interestingly, these inhibitors did not affect flg22-induced mitogen-activated protein kinase phosphorylation, indicating the ability to utilize vesicular trafficking inhibitors to target different flg22-signaling responses. For Tyrphostin A23, reduced flg22-induced reactive oxygen species could be separated from the defect in FLS2 degradation. At later times (>2 h) after the initial flg22 elicitation, recovery of FLS2 protein levels positively correlated with resensitization to flg22, indicating that flg22-induced new synthesis of FLS2 may prepare cells for a new round of monitoring the environment for flg22. PMID:24220680

  11. Poncirin Induces Apoptosis in AGS Human Gastric Cancer Cells through Extrinsic Apoptotic Pathway by up-Regulation of Fas Ligand

    Directory of Open Access Journals (Sweden)

    Venu Venkatarame Gowda Saralamma

    2015-09-01

    Full Text Available Poncirin, a natural bitter flavanone glycoside abundantly present in many species of citrus fruits, has various biological benefits such as anti-oxidant, anti-microbial, anti-inflammatory and anti-cancer activities. The anti-cancer mechanism of Poncirin remains elusive to date. In this study, we investigated the anti-cancer effects of Poncirin in AGS human gastric cancer cells (gastric adenocarcinoma. The results revealed that Poncirin could inhibit the proliferation of AGS cells in a dose-dependent manner. It was observed Poncirin induced accumulation of sub-G1 DNA content, apoptotic cell population, apoptotic bodies, chromatin condensation, and DNA fragmentation in a dose-dependent manner in AGS cells. The expression of Fas Ligand (FasL protein was up-regulated dose dependently in Poncirin-treated AGS cells Moreover, Poncirin in AGS cells induced activation of Caspase-8 and -3, and subsequent cleavage of poly(ADP-ribose polymerase (PARP. Inhibitor studies’ results confirm that the induction of caspase-dependent apoptotic cell death in Poncirin-treated AGS cells was led by the Fas death receptor. Interestingly, Poncirin did not show any effect on mitochondrial membrane potential (ΔΨm, pro-apoptotic proteins (Bax and Bak and anti-apoptotic protein (Bcl-xL in AGS-treated cells followed by no activation in the mitochondrial apoptotic protein caspase-9. This result suggests that the mitochondrial-mediated pathway is not involved in Poncirin-induced cell death in gastric cancer. These findings suggest that Poncirin has a potential anti-cancer effect via extrinsic pathway-mediated apoptosis, possibly making it a strong therapeutic agent for human gastric cancer.

  12. Poncirin Induces Apoptosis in AGS Human Gastric Cancer Cells through Extrinsic Apoptotic Pathway by up-Regulation of Fas Ligand.

    Science.gov (United States)

    Saralamma, Venu Venkatarame Gowda; Nagappan, Arulkumar; Hong, Gyeong Eun; Lee, Ho Jeong; Yumnam, Silvia; Raha, Suchismita; Heo, Jeong Doo; Lee, Sang Joon; Lee, Won Sup; Kim, Eun Hee; Kim, Gon Sup

    2015-09-18

    Poncirin, a natural bitter flavanone glycoside abundantly present in many species of citrus fruits, has various biological benefits such as anti-oxidant, anti-microbial, anti-inflammatory and anti-cancer activities. The anti-cancer mechanism of Poncirin remains elusive to date. In this study, we investigated the anti-cancer effects of Poncirin in AGS human gastric cancer cells (gastric adenocarcinoma). The results revealed that Poncirin could inhibit the proliferation of AGS cells in a dose-dependent manner. It was observed Poncirin induced accumulation of sub-G1 DNA content, apoptotic cell population, apoptotic bodies, chromatin condensation, and DNA fragmentation in a dose-dependent manner in AGS cells. The expression of Fas Ligand (FasL) protein was up-regulated dose dependently in Poncirin-treated AGS cells Moreover, Poncirin in AGS cells induced activation of Caspase-8 and -3, and subsequent cleavage of poly(ADP-ribose) polymerase (PARP). Inhibitor studies' results confirm that the induction of caspase-dependent apoptotic cell death in Poncirin-treated AGS cells was led by the Fas death receptor. Interestingly, Poncirin did not show any effect on mitochondrial membrane potential (ΔΨm), pro-apoptotic proteins (Bax and Bak) and anti-apoptotic protein (Bcl-xL) in AGS-treated cells followed by no activation in the mitochondrial apoptotic protein caspase-9. This result suggests that the mitochondrial-mediated pathway is not involved in Poncirin-induced cell death in gastric cancer. These findings suggest that Poncirin has a potential anti-cancer effect via extrinsic pathway-mediated apoptosis, possibly making it a strong therapeutic agent for human gastric cancer.

  13. Tumorigenesis induced by the HHV8-encoded chemokine receptor requires ligand modulation of high constitutive activity

    DEFF Research Database (Denmark)

    Holst, P J; Rosenkilde, M M; Manfra, D;

    2001-01-01

    ORF74 (or KSHV-vGPCR) is a highly constitutively active G protein-coupled receptor encoded by HHV8 that is regulated both positively and negatively by endogenous chemokines. When expressed in transgenic mice, this chemokine receptor induces an angioproliferative disease closely resembling Kaposi...... sarcoma (KS). Here we demonstrate that several lines of mice carrying mutated receptors deficient in either constitutive activity or chemokine regulation fail to develop KS-like disease. In addition, animals expressing a receptor that preserves chemokine binding and constitutive activity but that does...

  14. Ligand-induced expansion of the S1' site in the anthrax toxin lethal factor

    Energy Technology Data Exchange (ETDEWEB)

    Maize, Kimberly M.; Kurbanov, Elbek K.; Johnson, Rodney L.; Amin, Elizabeth Ambrose; Finzel, Barry C. (UMM)

    2016-07-05

    The Bacillus anthracis lethal factor (LF) is one component of a tripartite exotoxin partly responsible for persistent anthrax cytotoxicity after initial bacterial infection. Inhibitors of the zinc metalloproteinase have been investigated as potential therapeutic agents, but LF is a challenging target because inhibitors lack sufficient selectivity or possess poor pharmaceutical properties. These structural studies reveal an alternate conformation of the enzyme, induced upon binding of specific inhibitors, that opens a previously unobserved deep pocket termed S1'* which might afford new opportunities to design selective inhibitors that target this subsite.

  15. LH-Induced Steroidogenesis in the Mouse Ovary, but Not Testis, Requires Matrix Metalloproteinase 2- and 9-Mediated Cleavage of Upregulated EGF Receptor Ligands.

    Science.gov (United States)

    Light, Allison; Hammes, Stephen R

    2015-09-01

    Oocyte maturation and cumulus cell expansion depend on luteinizing hormone (LH)-mediated upregulation of membrane-bound epidermal growth factor (EGF)-like ligands, including amphiregulin, epiregulin, and betacellulin. These ligands then transactivate the EGF receptor (EGFR) after release by matrix metalloproteinases (MMPs). However, direct measurement of released EGF-like ligands or MMPs from granulosa cells has not been formally evaluated, nor has direct identification of responsible MMPs. Here we address these issues by analyzing LH-induced steroidogenesis, which is also MMP and EGFR dependent, in freshly isolated mouse primary granulosa cells. We demonstrate a correlation between amphiregulin and epiregulin mRNA induction and steroid production in LH-treated granulosa cells as well as in ovaries of human chorionic gonadotropin-treated mice. In contrast, LH does not alter Mmp1, Mmp2, Mmp3, Mmp8, Mmp9, or Adam17 mRNA expression. We demonstrate that, in primary mouse granulosa cells, LH triggers release of soluble amphiregulin that correlates with steroid production, both of which are blocked by MMP2/9 inhibition, confirming that MMP2/9 likely regulates LH-induced amphiregulin release and downstream processes. Notably, LH does not alter secretion of MMP2/9 from primary granulosa cells, nor does it modulate MMP activity. These findings indicate that, in the ovary, LH dictates EGFR-mediated processes not by regulating MMPs, but instead by increasing EGF-like ligand availability. In contrast, LH stimulation of primary mouse Leydig cells does not induce EGF-like ligand expression or require MMP2/9 for steroidogenesis, confirming marked differences in LH receptor-induced processes in the testes. Our results suggest that MMP inhibition may be a means of attenuating excess ovarian steroid production in diseases like polycystic ovary syndrome.

  16. Activation of TIM1 induces colon cancer cell apoptosis via modulating Fas ligand expression.

    Science.gov (United States)

    Wang, Hao; Zhang, Xueyan; Sun, Wenjing; Hu, Xiaocui; Li, Xiaolin; Fu, Songbin; Liu, Chen

    2016-04-29

    The pathogenesis of colon cancer is unclear. It is proposed that TIM1 has an association with human cancer. The present study aims to investigate the role of TIM1 activation in the inhibition of human colon cancer cells. In this study, human colon cancer cell line, HT29 and T84 cells were cultured. The expression of TIM1 was assessed by real time RT-PCR and Western blotting. The TIM1 on the cancer cells was activated in the culture by adding recombinant TIM4. The chromatin structure at the FasL promoter locus was assessed by chromatin immunoprecipitation. The apoptosis of the cancer cells was assessed by flow cytometry. The results showed that human colon cancer cell lines, HT29 cells and T84 cells, expressed TIM1. Activation of TIM1 by exposing the cells to TIM4 significantly increased the frequency of apoptotic colon cancer cells. The expression of FasL was increased in the cancer cells after treating by TIM4. Blocking Fas or FasL abolished the exposure to TIM4-induced T84 cell apoptosis. In conclusion, HT29 cells and T84 cells express TIM1; activation TIM1 can induce the cancer cell apoptosis. TIM1 may be a novel therapeutic target of colon cancer.

  17. Sigma1 receptor ligands and related neuroactive steroids interfere with the cocaine-induced state of memory.

    Science.gov (United States)

    Romieu, Pascal; Lucas, Morgan; Maurice, Tangui

    2006-07-01

    The present series of experiments examined the involvement of the sigma(1) receptor and related neuroactive steroids in the memory state induced by a very low dose of cocaine. Using a modified passive avoidance procedure in mice, we examined whether cocaine induces state-dependent (StD) learning. Animals trained and tested with saline or the same dose of cocaine (0.1 or 0.3 mg/kg) showed correct retention, measured using two independent parameters: the retention latency and a ratio between the retention latency and the last training latency. Animals trained with cocaine (0.1 mg/kg) and tested with saline or cocaine (0.03, 0.3 mg/kg), or trained with saline and tested with cocaine, showed altered retention parameters, demonstrating that StD occurred. Therefore, cocaine administered before training produced a chemical state used as an endogenous cue to insure optimal retention. Since sigma(1) receptor activation is an important event during the acquisition of cocaine reward, we tested several sigma(1) ligands and related neurosteroids. The sigma(1) agonist igmesine or antagonist BD1047 failed to produce StD, but modified the cocaine state. Among neuroactive steroids, pregnanolone and allopregnanolone, positive modulators of the gamma-aminobutyric acid type A (GABA(A)) receptor, produced StD. However, steroids also acting as sigma(1) agonists, dehydroepiandrosterone (3beta-hydroxy-5alpha-androsten-17-one (DHEA)), pregnenolone, or antagonist, progesterone, failed to induce StD but modified the cocaine state. Furthermore, optimal retention was observed with mice trained with (igmesine or DHEA)+cocaine and tested with a higher dose of cocaine, or with mice trained with (BD1047 or progesterone)+cocaine and tested with vehicle. This study demonstrated that: (i) low doses of cocaine induce a chemical state/memory trace sustaining StD; (ii) modulation of the sigma(1) receptor activation, although insufficient to provoke StD, modulates the cocaine state; (iii) neuroactive

  18. Significance of the first transcribed nucleoside of capped RNA for ligand-induced folding of the cap-binding complex

    Science.gov (United States)

    Worch, Remigiusz; Niedzwiecka, Anna; Stepinski, Janusz; Jankowska-Anyszka, Marzena; Mazza, Catherine; Darzynkiewicz, Edward; Cusack, Stephen; Stolarski, Ryszard

    2005-05-01

    Many proteins, including those that bind RNA, change conformation upon binding a ligand, a phenomenon known as induced fit. CBP20, the small subunit of the nuclear cap-binding complex (CBC), recognizes specifically the 5' cap of eukaryotic mRNA and snRNA. The N- and C-terminal regions of the CBP20 subunit of the human nuclear cap-binding complex only acquire a proper fold in complex with capped RNA. The cap is composed of 7-methylguanosine linked by a 5'-to-5' triphosphate bridge to the first transcribed nucleoside of the RNA. The significance of the latter for the capped RNA-CBC association and local folding of CBC has been characterized by emission spectroscopy. Fluorescence titration of CBC has been performed for three selected, mono- and dinucleotide mRNA 5' cap analogues. The measured values of the equilibrium association constant and the corresponding Gibbs free energy depend on the type of the first transcribed nucleoside (purine or pyrimidine), and decrease ~10-fold in the case of a mononucleotide analogue, 7-methylguanosine triphosphate. However, the total quenching of the intrinsic protein fluorescence is similar for each analogue. Changes of the solvent-accessible CBC hydrophobic surface of CBC on binding of the structurally different cap analogues have been followed using bis-ANS fluorescent probe.

  19. TNF–related apoptosis-inducing ligand (TRAIL and erythropoiesis: a role for PKCe

    Directory of Open Access Journals (Sweden)

    M Vitale

    2009-06-01

    Full Text Available The regulation of the hematopoietic stem cell pool size and the processes of cell differentiation along the hematopoietic lineages involve apoptosis. Among the different factors with a recognized activity on blood progenitor cells, TRAIL - a member of the TNF family of cytokines - has an emerging role in the modulation of normal hematopoiesis. PKCÂ levels are regulated by EPO in differentiating erythroid progenitors and control the protection against the apoptogenic effect of TRAIL. EPO-induced erythroid CD34 cells are insensitive to the apoptogenic effect of TRAIL between day 0 and day 3, due to the lack of specific surface receptors expression. Death receptors appear after day 3 of differentiation and consequently erythoid cells became sensitive to TRAIL up to day 9/10, when the EPO-driven up-regulation of PKCe intracellular levels inhibits the TRAIL-mediated apoptosis, via Bcl-2. In the time interval between day 3 and 9, therefore, the number of erythroid progenitors can be limited by the presence of soluble or membrane-bound TRAIL present in the bone marrow microenvironment.

  20. Laser-induced down-conversion and infrared phosphorescence emissivity of novel ligand-free perovskite nanomaterials

    Science.gov (United States)

    Ahmed, M. A.; Khafagy, Rasha M.; El-sayed, O.

    2014-03-01

    For the first time, standalone and ligand-free series of novel rare-earth-based perovskite nanomaterials are used as near infrared (NIR) and mid infrared (MIR) emitters. Nano-sized La0.7Sr0.3M0.1Fe0.9O3; where M = 0, Mn2+, Co2+ or Ni2+ were synthesized using the flash auto-combustion method and characterized using FTIR, FT-Raman, SEM and EDX. Photoluminescence spectra were spontaneously recorded during pumping the samples with 0.5 mW of green laser emitting continuously at 532 nm. La0.7Sr0.3FeO3 (where M = 0) did not result in any infrared emissivity, while intense near and mid infrared down-converted phosphorescence was released from the M-doped samples. The released phosphorescence greatly shifted among the infrared spectral region with changing the doping cation. Ni2+-doped perovskite emitted at the short-wavelength near-infrared region, while Mn2+ and Co2+-doped perovskites emitted at the mid-wavelength infrared region. The detected laser-induced spontaneous parametric down-conversion phosphorescence (SPDC) occurred through a two-photon process by emitting two NIR or MIR photons among a cooperative energy transfer between the La3+ cations and the M2+ cations. Combining SrFeO3 ceramic with both a rare earth cation (RE3+) and a transition metal cation (Mn2+, Co2+ or Ni2+), rather than introducing merely RE3+ cations, greatly improved and controlled the infrared emissivity properties of synthesized perovskites through destroying their crystal symmetry and giving rise to asymmetrical lattice vibration and the nonlinear optical character. The existence of SPDC in the M2+-doped samples verifies their nonlinear character after the absence of this character in La0.7Sr0.3FeO3. Obtained results verify that, for the first time, perovskite nanomaterials are considered as nonlinear optical crystals with intense infrared emissivity at low pumping power of visible wavelengths, which nominates them for photonic applications and requires further studies regarding their lasing

  1. Enhancement of peripheral benzodiazepine receptor ligand-induced apoptosis and cell cycle arrest of esophageal cancer cells by simultaneous inhibition of MAPK/ERK kinase.

    Science.gov (United States)

    Sutter, Andreas P; Maaser, Kerstin; Gerst, Bastian; Krahn, Antje; Zeitz, Martin; Scherübl, Hans

    2004-05-01

    Specific ligands of the peripheral benzodiazepine receptor (PBR) activate pro-apoptotic and anti-proliferative signaling pathways. Previously, we found that PBR ligands activated the p38 mitogen-activated protein kinase (MAPK) pathway in esophageal cancer cells, and that the activation of p38MAPK contributed to tumor cell apoptosis and cell cycle arrest. Here, we report that PBR ligands also activate the pro-survival MAPK/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway in esophageal cancer cells, which might compromise the efficacy of PBR ligands. Hence, a combination treatment of PBR ligands and MEK inhibitors, which are emerging as promising anticancer agents, was pursued to determine whether this treatment could lead to enhanced apoptosis and cell cycle arrest. Using Western blotting we demonstrated a time- and dose-dependent phosphorylation of ERK1/2 in response to PBR ligands. Apoptosis was investigated by assessment of mitochondrial alterations and caspase-3 activity. Cell cycle arrest was measured by flow cytometric analysis of stained isolated nuclei. The inhibition of MEK/ERK with a pharmacologic inhibitor, 2'-amino-3'-methoxyflavone (PD 98059), resulted in a synergistic enhancement of PBR-ligand-induced growth inhibition, apoptosis and cell cycle arrest. Specifity of the pharmacologic inhibitor was confirmed by the use of 1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene (U 0126), a second MEK/ERK inhibitor, and 1,4-diamino-2,3-dicyano-1,4-bis(methylthio)butadiene (U 0124), a structural analogue of it which does not display any affinity to MEK. Enhanced pro-apoptotic and anti-proliferative effects were observed both in KYSE-140 esophageal squamous cancer and OE-33 adenocarcinoma cells, suggesting that this effect was not cell-type specific. In addition, the PBR-mediated overexpression of the stress response gene (growth arrest and DNA-damage-inducible gene gadd153) was synergistically enhanced by MEK inhibition. This is the

  2. Fluorescence study on ligand induced conformational changes of glutamine synthetase from Bacillus brevis Bb G1 under sporulating conditions

    Directory of Open Access Journals (Sweden)

    SUJA ABRAHAM

    2015-04-01

    Full Text Available Glutamine synthetase, an important enzyme of nitrogen metabolism, was purified under sporulating conditions (GSala. The effect of ligands on the tryptophan fluorescence of the purified enzyme GSala was investigated. With increasing concentrations of L-glutamine in GSala, a blue shift in emission maximum with an increase in fluorescence intensity and decrease in life times were observed compared to the emission maximum, fluorescence intensity and life times of GSala. With increasing concentrations of glycine in GSala, a shift in emission maximum, change in fluorescence intensity and change in lifetimes were observed compared to the emission maximum, fluorescence intensity and life times of GSala. These observations strongly support the possibility that GSala undergoes a conformational change on binding with ligands and each ligand produced different conformational changes in GSala. Also, different concentrations of each ligand produced different protein conformations in the enzyme GSala.

  3. EXPRESSION OF MATRIX METALLOPROTEINASE-7 AND FAS LIGAND: THEIR APOPTOSIS-INDUCING EFFECT ON GASTRIC CANCER CELLS

    Institute of Scientific and Technical Information of China (English)

    郑华川; 杨雪飞; 孙晋民; 李晓晗; 姜卫国; 张荫昌; 辛彦

    2003-01-01

    Objective: To investigate the expression of matrix metalloproteinase-7 (MMP-7) and Fas ligand (FasL) in gastric cancer and explore their role in progression of gastric cancer. Methods: Formalin-fixed paraffin and embedded tissues of primary gastric cancer and adjacent non-tumor mucosa from 113 cases were evaluated for MMP-7, FasL and Capase-3 expression by streptavidin-peroxidase (S-P) immunohistochemistry. The expression of the first two proteins in cancer cells of primary foci was compared with clinicopathological parameters of tumors. We also observed the correlation of MMP-7 and FasL expression with Caspase-3 expression in cancer cells of primary foci. Results: MMP-7 positive immunostaining was less frequently detected in adjacent epithelial cells than in cancer cells of primary foci of gastric cancer (P0.05). FasL expression was correlated with tumor size, invasive depth, metastasis, Lauren's classification, histological classification (P0.05). Cancer cells of primary foci expressed less Caspase-3 than their adjacent epithelial cells (P<0.05, 32.7% vs 50.4%). There was an obvious correlation between FasL, MMP-7 and Caspase-3 expression in cancer cells of primary foci (P<0.05). Co-expression of MMP-7 and FasL paralleled with Caspase-3 expression in cancer cells of primary foci (P<0.05). Conclusion: MMP-7 and FasL expression was up-regulated in gastric carcinogenesis and was principally involved in progression of gastric cancer. FasL expression could reflect the differentiation of gastric cancer cells and underlie the molecular mechanisms of different pathways of gastric tumorigenesis. Co-expression of MMP-7 and FasL could have apoptosis-inducing effect on gastric cancer cells.

  4. Osteonecrosis of the jaw induced by receptor activator of nuclear factor-kappa B ligand (Denosumab) - Review

    Science.gov (United States)

    Brizeno, Luiz-André-Cavalcante; de Sousa, Fabrício-Bitu; Mota, Mário-Rogério-Lima; Alves, Ana-Paula-Negreiros-Nunes

    2016-01-01

    Background Denosumab, an anti-resorptive agent, IgG2 monoclonal antibody for human Receptor activator of nuclear factor-kappa B ligand (RANKL), has been related to the occurrence of osteonecrosis of the jaws. Thus, the aim of this study was to review the literature from clinical case reports, regarding the type of patient and the therapeutic approach used for osteonecrosis of the jaws induced by chronic use of Denosumab. Material and Methods For this, a literature review was performed on PubMed, Medline and Cochrane databases, using the keywords “Denosumab” “anti-RANK ligand” and “Osteonecrosis of jaw”. To be included, articles should be a report or a serie of clinical cases, describing patients aged 18 years or over who used denosumab therapy and have received any therapy for ONJ. Results Thirteen complete articles were selected for this review, totaling 17 clinical cases. The majority of ONJ cases, patients receiving Denosumab as treatment for osteoporosis and prostate cancer therapy. In most cases, patients affected by ONJ were women aged 60 or over and posterior mandible area was the main site of involvement. Diabetes pre-treatment with bisphosphonates and exodontia were the most often risk factors related to the occurrence of this condition. It is concluded that the highest number of ONJ cases caused by the use of anti-RANKL agents occurred in female patients, aged 60 years or older, under treatment for osteoporosis and cancer metastasis, and the most affected region was the mandible posterior. Conclusions The results presented in this article are valid tool supporting the non-invasive mapping of facial vascularization. Key words:Denosumab, osteonecrosis, adverse effects, osteoporosis, antineoplastic protocols. PMID:26827069

  5. Helicobacter pylori enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in human gastric epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Yi-Ying Wu; Hwei-Fang Tsai; We-Cheng Lin; Ai-Hsiang Chou; Hui-Ting Chen; Jyh-Chin Yang; Ping-I Hsu; Ping-Ning Hsu

    2004-01-01

    AIM: To investigate the relations between tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Helicobacter pylori(H pylori) infection in apoptosis of gastric epithelial cells and to assess the expression of TRAIL onthe surface of infiltrating T-cells in Hpylori-infected gastric mucosa.METHODS: Human gastric epithelial cell lines and primary gastric epithelial cells were co-cultured with H pylori in vitro, then recombinant TRAIL proteins were added to the culture. Apoptosis of gastric epithelial cells was determined by a specific ELISA for cell death. Infiltrating lymphocytes were isolated from H pylori-infected gastric mucosa, and expression of TRAIL in T cells was analyzed by flow cytometry.RESULTS: The apoptosis of gastric epithelial cell lines and primary human gastric epithelial cells was mildly increased by interaction with either TRAIL or H pylorialone. Interestingly,the apoptotic indices were markedly elevated when gastric epithelial cells were incubated with both TRAIL and H pylori (Control vsTRAIL and H pylori: 0.51±0.06 vs 2.29±0.27,P = 0.018). A soluble TRAIL receptor (DR4-Fc) could specifically block the TRAIL-mediated apoptosis. Further studies demonstrated that infiltrating T-cells in gastric mucosa expressed TRAIL on their surfaces, and the induction of TRAIL sensitivity by H pylori was dependent upon direct cell contact of viable bacteria, but not CagA and VacA of H pylori.CONCLUSION: H pylori can sensitize human gastric epithelial ceils and enhance susceptibility to TRAIL-mediated apoptosis. Modulation of host cell sensitivity to apoptosis by bacterial interaction adds a new dimension to the immunopathogenesis of H pylori infection.

  6. Ligand- and mutation-induced conformational selection in the CCR5 chemokine G protein-coupled receptor.

    Science.gov (United States)

    Abrol, Ravinder; Trzaskowski, Bartosz; Goddard, William A; Nesterov, Alexandre; Olave, Ivan; Irons, Christopher

    2014-09-09

    We predicted the structural basis for pleiotropic signaling of the C-C chemokine type 5 (CCR5) G protein-coupled receptor (GPCR) by predicting the binding of several ligands to the lower-energy conformations of the CCR5 receptor and 11 mutants. For each case, we predicted the ∼ 20 most stable conformations for the receptor along with the binding sites for four anti-HIV ligands. We found that none of the ligands bind to the lowest-energy apo-receptor conformation. The three ligands with a similar pharmacophore (Maraviroc, PF-232798, and Aplaviroc) bind to a specific higher-energy receptor conformation whereas TAK-779 (with a different pharmacophore) binds to a different high-energy conformation. This result is in agreement with the very different binding-site profiles for these ligands obtained by us and others. The predicted Maraviroc binding site agrees with the recent structure of CCR5 receptor cocrystallized with Maraviroc. We performed 11 site-directed mutagenesis experiments to validate the predicted binding sites. Here, we independently predicted the lowest 10 mutant protein conformations for each of the 11 mutants and then docked the ligands to these lowest conformations. We found the predicted binding energies to be in excellent agreement with our mutagenesis experiments. These results show that, for GPCRs, each ligand can stabilize a different protein conformation, complicating the use of cocrystallized structures for ligand screening. Moreover, these results show that a single-point mutation in a GPCR can dramatically alter the available low-energy conformations, which in turn alters the binding site, potentially altering downstream signaling events. These studies validate the conformational selection paradigm for the pleiotropic function and structural plasticity of GPCRs.

  7. Crystallographic evidence of a large ligand-induced hinge-twist motion between the two domains of the maltodextrin binding protein involved in active transport and chemotaxis.

    Science.gov (United States)

    Sharff, A J; Rodseth, L E; Spurlino, J C; Quiocho, F A

    1992-11-10

    The periplasmic maltodextrin binding protein of Escherichia coli serves as an initial receptor for the active transport of and chemotaxis toward maltooligosaccharides. The three-dimensional structure of the binding protein complexed with maltose has been previously reported [Spurlino, J. C., Lu, G.-Y., & Quiocho, F. A. (1991) J. Biol. Chem. 266, 5202-5219]. Here we report the structure of the unliganded form of the binding protein refined to 1.8-A resolution. This structure, combined with that for the liganded form, provides the first crystallographic evidence that a major ligand-induced conformational change occurs in a periplasmic binding protein. The unliganded structure shows a rigid-body "hinge-bending" between the two globular domains by approximately 35 degrees, relative to the maltose-bound structure, opening the sugar binding site groove located between the two domains. In addition, there is an 8 degrees twist of one domain relative to the other domain. The conformational changes observed between this structure and the maltose-bound structure are consistent with current models of maltose/maltodextrin transport and maltose chemotaxis and solidify a mechanism for receptor differentiation between the ligand-free and ligand-bound forms in signal transduction.

  8. Chemotherapeutic drugs induce PPAR-gamma expression and show sequence-specific synergy with PPAR-gamma ligands in inhibition of non-small cell lung cancer.

    Science.gov (United States)

    Reddy, Raju C; Srirangam, Anjaiah; Reddy, Kaunteya; Chen, Jun; Gangireddy, Srinivasareddy; Kalemkerian, Gregory P; Standiford, Theodore J; Keshamouni, Venkateshwar G

    2008-06-01

    Preclinical studies have shown that peroxisome proliferator-activated receptor gamma (PPAR-gamma) ligands can exert antitumor effects against non-small cell lung cancer (NSCLC) and a variety of other cancers. In this study, we investigate the potential use of a PPAR-gamma ligand, troglitazone (Tro), in combination with either of two chemotherapeutic agents, cisplatin (Cis) or paclitaxel (Pac), for the treatment of NSCLC. In vitro, treatment of NSCLC cell lines with Tro potentiated Cis- or Pac-induced growth inhibition. The potentiation of growth inhibition was observed only when Cis or Pac treatment was followed by Tro and not vice versa, demonstrating a sequence-specific effect. Median effect analysis revealed a synergistic interaction between Tro and Cis in the inhibition of NSCLC cell growth and confirmed the sequence-specific effect. We also found that Cis or Pac up-regulated the expression of PPAR-gamma protein, accounting for the observed sequence-specific synergy. Similarly, experiments performed using a NSCLC xenograft model demonstrated enhanced effectiveness of combined treatment with Cis and PPAR-gamma ligands, Tro or pioglitazone. Tumors from Cis-treated mice also demonstrated enhanced PPAR-gamma expression. Together, our data demonstrate a novel sequence-specific synergy between PPAR-gamma ligands and chemotherapeutic agents for lung cancer treatment.

  9. Chemotherapeutic Drugs Induce PPAR-γ Expression and Show Sequence-Specific Synergy with PPAR-γ Ligands in Inhibition of Non-Small Cell Lung Cancer1

    Science.gov (United States)

    Reddy, Raju C; Srirangam, Anjaiah; Reddy, Kaunteya; Chen, Jun; Gangireddy, Srinivasareddy; Kalemkerian, Gregory P; Standiford, Theodore J; Keshamouni, Venkateshwar G

    2008-01-01

    Preclinical studies have shown that peroxisome proliferator-activated receptor γ (PPAR-γ) ligands can exert antitumor effects against non-small cell lung cancer (NSCLC) and a variety of other cancers. In this study, we investigate the potential use of a PPAR-γ ligand, troglitazone (Tro), in combination with either of two chemotherapeutic agents, cisplatin (Cis) or paclitaxel (Pac), for the treatment of NSCLC. In vitro, treatment of NSCLC cell lines with Tro potentiated Cis- or Pac-induced growth inhibition. The potentiation of growth inhibition was observed only when Cis or Pac treatment was followed by Tro and not vice versa, demonstrating a sequence-specific effect. Median effect analysis revealed a synergistic interaction between Tro and Cis in the inhibition of NSCLC cell growth and confirmed the sequence-specific effect. We also found that Cis or Pac up-regulated the expression of PPAR-γ protein, accounting for the observed sequence-specific synergy. Similarly, experiments performed using a NSCLC xenograft model demonstrated enhanced effectiveness of combined treatment with Cis and PPAR-γ ligands, Tro or pioglitazone. Tumors from Cis-treated mice also demonstrated enhanced PPAR-γ expression. Together, our data demonstrate a novel sequence-specific synergy between PPAR-γ ligands and chemotherapeutic agents for lung cancer treatment. PMID:18516296

  10. Ligand-induced tyrosine phosphorylation of cysteinyl leukotriene receptor 1 triggers internalization and signaling in intestinal epithelial cells.

    Directory of Open Access Journals (Sweden)

    Ladan Parhamifar

    Full Text Available BACKGROUND: Leukotriene D(4 (LTD(4 belongs to the bioactive lipid group known as eicosanoids and has implications in pathological processes such as inflammation and cancer. Leukotriene D(4 exerts its effects mainly through two different G-protein-coupled receptors, CysLT(1 and CysLT(2. The high affinity LTD(4 receptor CysLT(1R exhibits tumor-promoting properties by triggering cell proliferation, survival, and migration in intestinal epithelial cells. In addition, increased expression and nuclear localization of CysLT(1R correlates with a poorer prognosis for patients with colon cancer. METHODOLOGY/PRINCIPAL FINDINGS: Using a proximity ligation assay and immunoprecipitation, this study showed that endogenous CysLT(1R formed heterodimers with its counter-receptor CysLT(2R under basal conditions and that LTD(4 triggers reduced dimerization of CysLTRs in intestinal epithelial cells. This effect was dependent upon a parallel LTD(4-induced increase in CysLT(1R tyrosine phosphorylation. Leukotriene D(4 also led to elevated internalization of CysLT(1Rs from the plasma membrane and a simultaneous increase at the nucleus. Using sucrose, a clathrin endocytic inhibitor, dominant-negative constructs, and siRNA against arrestin-3, we suggest that a clathrin-, arrestin-3, and Rab-5-dependent process mediated the internalization of CysLT(1R. Altering the CysLT(1R internalization process at either the clathrin or the arrestin-3 stage led to disruption of LTD(4-induced Erk1/2 activation and up-regulation of COX-2 mRNA levels. CONCLUSIONS/SIGNIFICANCE: Our data suggests that upon ligand activation, CysLT(1R is tyrosine-phosphorylated and released from heterodimers with CysLT(2R and, subsequently, internalizes from the plasma membrane to the nuclear membrane in a clathrin-, arrestin-3-, and Rab-5-dependent manner, thus, enabling Erk1/2 signaling and downstream transcription of the COX-2 gene.

  11. Anti-liver cancer activity of TNF-related apoptosis-inducing ligand gene and its bystander effects

    Institute of Scientific and Technical Information of China (English)

    Chao He; Wei-Feng Lao; Xiao-Tong Hu; Xiang-Ming Xu; Jing Xu; Bing-Liang Fang

    2004-01-01

    AIM: To observe the anti-liver cancer activity of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene and its bystander effects on hepatocellular carcinoma (HCC) cell line SMMC7721.METHODS: Full-length cDNA of human TRAIL was transferred into SMMC7721 cells with a binary adenoviral vector system.Polymerase-chain reaction following reverse transcription (RT-PCR) was used to determine the expression of TRAIL gene. Effects of the transfected gene on proliferation of SMMC7721 cells were measured by MTT assay. Its influence on apoptosis was demonstrated by fluorescence-activated cell sorting (FACS). The bystander effect was observed by co-culturing the SMNC7721 cells with and without the transfected TRAIL gene at different ratios, and the culture medium supernatant from the transfected cells was also examined for its influence on SMMC7721 cells.RESULTS: The growth-inhibition rate and apoptotic cell fraction in the cells transfected with the TRAIL gene, Bax gene or only LacZ gene were 91.2%, 48.0%, 28.8% and 29.1%, 12.5%, 6.6%, respectively. The growth-inhibition rate of transfection with these three sequences in normal human fibroblasts was 6.1%, 45.5% and 7.6%, respectively,indicating a discriminative inhibition of TRAIL transfection on the cancer cells. In the co-culturing test, addition of the transfected TRAIL to SMMC7721 cells in proportions of 5%,25%, 50%, 75% and 100%, resulted in a growth-inhibition of 15.9%, 67%, 80.2%, 86.4% and 87.7%, respectively.We failed to observe a significant growth-inhibition effect of the culture medium supernatant on SMMC7721 cells.CONCLUSION: TRAIL gene transferred by a binary adenoviral vector system can inhibit proliferation of SMMC7721 cells and induce their apoptosis. A bystander effect was observed,which seemed not to be mediated by soluble factors.

  12. Expression of osteoprotegerin, receptor activator of nuclear factor kappa-B ligand, tumor necrosis factor-related apoptosis-inducing ligand, stromal cell-derived factor-1 and their receptors in epithelial metastatic breast cancer cell lines

    Directory of Open Access Journals (Sweden)

    Labovsky Vivian

    2012-06-01

    Full Text Available Abstract Background While breast cancer (BC is the major cause of death among women worldwide, there is no guarantee of better patient survival because many of these patients develop primarily metastases, despite efforts to detect it in its early stages. Bone metastasis is a common complication that occurs in 65-80 % of patients with disseminated disease, but the molecular basis underlying dormancy, dissemination and establishment of metastasis is not understood. Our objective has been to evaluate simultaneously osteoprotegerin (OPG, receptor activator of nuclear factor kappa B ligand (RANKL, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL, stromal cell-derived factor-1 (SDF-1, and their receptors (R in 2 human BC cell lines, MDA-MB-231 and MCF-7. Methods OPG, RANKL, TRAIL and SDF-1 expression and release, in addition to the expression of their receptors has been investigated using immunofluorescence, immunocytochemistry and ELISA analyses. Results MCF-7 cells released higher levels of OPG in conditioned media (CM than MDA-MB-231 cells; 100 % of both types of cell expressed OPG, RANKL, TRAIL and SDF-1. Moreover, 100 % in both lines expressed membrane RANKL and RANK, whereas only 50 % expressed CXCR4. Furthermore, 100 % expressed TRAIL-R1 and R4, 30-50 % TRAIL-R2, and 40-55 % TRAIL-R3. Conclusions MCF-7 and MDA-MB-231 cells not only released OPG, but expressed RANKL, TRAIL and SDF-1. The majority of the cells also expressed RANK, CXCR4 and TRAIL-R. Since these ligands and their receptors are implicated in the regulation of proliferation, survival, migration and future bone metastasis during breast tumor progression, assessment of these molecules in tumor biopsies of BC patients could be useful in identifying patients with more aggressive tumors that are also at risk of bone metastasis, which may thus improve the available options for therapeutic intervention.

  13. A chemometric analysis of ligand-induced changes in intrinsic fluorescence of folate binding protein indicates a link between altered conformational structure and physico-chemical characteristics

    DEFF Research Database (Denmark)

    Bruun, Susanne W; Holm, Jan; Hansen, Steen Ingemann

    2009-01-01

    Ligand binding alters the conformational structure and physico-chemical characteristics of bovine folate binding protein (FBP). For the purpose of achieving further information we analyzed ligand (folate and methotrexate)-induced changes in the fluorescence landscape of FBP. Fluorescence excitation...... and emission two-dimensional (2D) spectra were recorded over a wide range of wavelengths on a Perkin-Elmer LS 55 spectrofluorometer at varying pH in different buffers, and the resulting three-dimensional data were subjected to a chemometric analysis, parallel factor analysis (PARAFAC). The most important...... of folate accords fairly well with the disappearance of strongly hydrophobic tryptophan residues from the solvent-exposed surface of FBP. The PARAFAC has thus proven useful to establish a hitherto unexplained link between parallel changes in conformational structure and physico-chemical characteristics...

  14. Cationic lipids and cationic ligands induce DNA helix denaturation: detection of single stranded regions by KMnO4 probing.

    Science.gov (United States)

    Prasad, T K; Gopal, Vijaya; Rao, N Madhusudhana

    2003-09-25

    Cationic lipids and cationic polymers are widely used in gene delivery. Using 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as a cationic lipid, we have investigated the stability of the DNA in DOTAP:DNA complexes by probing with potassium permanganate (KMnO4). Interestingly, thymidines followed by a purine showed higher susceptibility to cationic ligand-mediated melting. Similar studies performed with other water-soluble cationic ligands such as polylysine, protamine sulfate and polyethyleneimine also demonstrated melting of the DNA but with variations. Small cations such as spermine and spermidine and a cationic detergent, cetyl trimethylammonium bromide, also rendered the DNA susceptible to modification by KMnO4. The data presented here provide direct proof for melting of DNA upon interaction with cationic lipids. Structural changes subsequent to binding of cationic lipids/ligands to DNA may lead to instability and formation of DNA bubbles in double-stranded DNA.

  15. PPARγ ligands switched high fat diet-induced macrophage M2b polarization toward M2a thereby improving intestinal Candida elimination.

    Directory of Open Access Journals (Sweden)

    Lise Lefèvre

    Full Text Available Obesity is associated with a chronic low-grade inflammation that predisposes to insulin resistance and the development of type 2 diabetes. In this metabolic context, gastrointestinal (GI candidiasis is common. We recently demonstrated that the PPARγ ligand rosiglitazone promotes the clearance of Candida albicans through the activation of alternative M2 macrophage polarization. Here, we evaluated the impact of high fat diet (HFD-induced obesity and the effect of rosiglitazone (PPARγ ligand or WY14643 (PPARα ligand both on the phenotypic M1/M2 polarization of peritoneal and cecal tissue macrophages and on the outcome of GI candidiasis. We demonstrated that the peritoneal macrophages and the cell types present in the cecal tissue from HF fed mice present a M2b polarization (TNF-α(high, IL-10(high, MR, Dectin-1. Interestingly, rosiglitazone induces a phenotypic M2b-to-M2a (TNF-α(low, IL-10(low, MR(high, Dectin-1(high switch of peritoneal macrophages and of the cells present in the cecal tissue. The incapacity of WY14643 to switch this polarization toward M2a state, strongly suggests the specific involvement of PPARγ in this mechanism. We showed that in insulin resistant mice, M2b polarization of macrophages present on the site of infection is associated with an increased susceptibility to GI candidiasis, whereas M2a polarization after rosiglitazone treatment favours the GI fungal elimination independently of reduced blood glucose. In conclusion, our data demonstrate a dual benefit of PPARγ ligands because they promote mucosal defence mechanisms against GI candidiasis through M2a macrophage polarization while regulating blood glucose level.

  16. Field-Induced Co(II) Single-Ion Magnets with mer-Directing Ligands but Ambiguous Coordination Geometry.

    Science.gov (United States)

    Peng, Yan; Mereacre, Valeriu; Anson, Christopher E; Zhang, Yiquan; Bodenstein, Tilmann; Fink, Karin; Powell, Annie K

    2017-06-05

    Three air-stable Co(II) mononuclear complexes with different aromatic substituents have been prepared and structurally characterized by single-crystal X-ray diffraction. The mononuclear complexes [Co(H2L1)2]·2THF (1), [Co(HL2)2] (2), and [Co(H2L3)2]·CH2Cl2 (3) (where H3L1, H2L2, and H3L3 represent 3-hydroxy-naphthalene-2-carboxylic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, nicotinic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, and 2-hydroxy-benzoic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, respectively) feature a distorted mer octahedral coordination geometry. Detailed magnetic studies of 1-3 have been conducted using direct and alternating current magnetic susceptibility data. Field-induced slow magnetic relaxation was observed for these three complexes. There are few examples of such behavior in (distorted) octahedral coordination geometry (OC) Co(II) mononuclear complexes with uniaxial anisotropy. Analysis of the six-coordinate Co(II) mononuclear single-ion magnets (SIMs) in the literature using the SHAPE program revealed that they all show what is best described as distorted trigonal prismatic (TRP) coordination geometry, and in general, these show negative D zero-field splitting (ZFS) values. On the other hand, all the Co(II) mononuclear complexes displaying what is best approximated as distorted octahedral (OC) coordination geometry show positive D values. In the new Co(II) mononuclear complexes we describe here, there is an ambiguity, since the rigid tridentate ligands confer what is best described for an octahedral complex as a mer coordination geometry, but the actual shape of the first coordination sphere is between octahedral and trigonal prismatic. The negative D values observed experimentally and supported by high-level electronic structure calculations are thus in line with a trigonal prismatic geometry. However, a consideration of the rhombicity as indicated by the E value of the ZFS in conjunction with the

  17. PPAR-γ ligands repress TGFβ-induced myofibroblast differentiation by targeting the PI3K/Akt pathway: implications for therapy of fibrosis.

    Directory of Open Access Journals (Sweden)

    Ajit A Kulkarni

    Full Text Available Transforming growth factor beta (TGFβ induced differentiation of human lung fibroblasts to myofibroblasts is a key event in the pathogenesis of pulmonary fibrosis. Although the typical TGFβ signaling pathway involves the Smad family of transcription factors, we have previously reported that peroxisome proliferator-activated receptor-γ (PPAR-γ ligands inhibit TGFβ-mediated differentiation of human lung fibroblasts to myofibroblasts via a Smad-independent pathway. TGFβ also activates the phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt pathway leading to phosphorylation of Akt(S473. Here, we report that PPAR-γ ligands, 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO and 15-deoxy-(12,14-15d-prostaglandin J(2 (15d-PGJ(2, inhibit human myofibroblast differentiation of normal and idiopathic pulmonary fibrotic (IPF fibroblasts, by blocking Akt phosphorylation at Ser473 by a PPAR-γ-independent mechanism. The PI3K inhibitor LY294002 and a dominant-negative inactive kinase-domain mutant of Akt both inhibited TGFβ-stimulated myofibroblast differentiation, as determined by Western blotting for α-smooth muscle actin and calponin. Prostaglandin A(1 (PGA(1, a structural analogue of 15d-PGJ(2 with an electrophilic center, also reduced TGFβ-driven phosphorylation of Akt, while CAY10410, another analogue that lacks an electrophilic center, did not; implying that the activity of 15d-PGJ(2 and CDDO is dependent on their electrophilic properties. PPAR-γ ligands inhibited TGFβ-induced Akt phosphorylation via both post-translational and post-transcriptional mechanisms. This inhibition is independent of MAPK-p38 and PTEN but is dependent on TGFβ-induced phosphorylation of FAK, a kinase that acts upstream of Akt. Thus, PPAR-γ ligands inhibit TGFβ signaling by affecting two pro-survival pathways that culminate in myofibroblast differentiation. Further studies of PPAR-γ ligands and small electrophilic molecules may lead to a new generation of

  18. DEPENDENCE OF PPAR LIGAND-INDUCED MAPK SIGNALING ON EPIDERMAL GROWTH FACTOR RECEPTOR TRANSACTIVATION HEPARIN-BINDING EGF CLEAVAGE MEDIATES ZINC-INDUCED EGF RECEPTOR PHOSPHORYLATION

    Science.gov (United States)

    Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that function as ligand-activated transcription factors regulating lipid metabolism and homeostasis. In addition to their ability to regulate PPAR-mediated gene transcription, PPARalpha and gamma li...

  19. Combined Treatment With Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands and Gamma Radiation Induces Apoptosis by PPARγ-Independent Up-Regulation of Reactive Oxygen Species-Induced Deoxyribonucleic Acid Damage Signals in Non-Small Cell Lung Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Han, Eun Jong; Im, Chang-Nim; Park, Seon Hwa [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Moon, Eun-Yi [Department of Bioscience and Biotechnology, Sejong University, Seoul (Korea, Republic of); Hong, Sung Hee, E-mail: gobrian@kcch.re.kr [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2013-04-01

    Purpose: To investigate possible radiosensitizing activities of the well-known peroxisome proliferator-activated receptor (PPAR)γ ligand ciglitazone and novel PPARγ ligands CAY10415 and CAY10506 in non-small cell lung cancer (NSCLC) cells. Methods and Materials: Radiosensitivity was assessed using a clonogenic cell survival assay. To investigate the mechanism underlying PPARγ ligand-induced radiosensitization, the subdiploid cellular DNA fraction was analyzed by flow cytometry. Activation of the caspase pathway by combined PPARγ ligands and γ-radiation treatment was detected by immunoblot analysis. Reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate and flow cytometry. Results: The 3 PPARγ ligands induced cell death and ROS generation in a PPARγ-independent manner, enhanced γ-radiation–induced apoptosis and caspase-3–mediated poly (ADP-ribose) polymerase (PARP) cleavage in vitro. The combined PPARγ ligand/γ-radiation treatment triggered caspase-8 activation, and this initiator caspase played an important role in the combination-induced apoptosis. Peroxisome proliferator-activated receptor-γ ligands may enhance the γ-radiation-induced DNA damage response, possibly by increasing γ-H2AX expression. Moreover, the combination treatment significantly increased ROS generation, and the ROS scavenger N-acetylcysteine inhibited the combined treatment-induced ROS generation and apoptotic cell death. Conclusions: Taken together, these results indicated that the combined treatment of PPARγ ligands and γ-radiation synergistically induced DNA damage and apoptosis, which was regulated by ROS.

  20. Recombinant Lipoprotein Rv1016c Derived from Mycobacterium tuberculosis Is a TLR-2 Ligand that Induces Macrophages Apoptosis and Inhibits MHC II Antigen Processing.

    Science.gov (United States)

    Su, Haibo; Zhu, Shenglin; Zhu, Lin; Huang, Wei; Wang, Honghai; Zhang, Zhi; Xu, Ying

    2016-01-01

    TLR2-dependent cellular signaling in Mycobacterium tuberculosis-infected macrophages causes apoptosis and inhibits class II major histocompatibility complex (MHC-II) molecules antigen processing, leading to evasion of surveillance. Mycobacterium tuberculosis (MTB) lipoproteins are an important class of Toll-like receptor (TLR) ligand, and identified as specific components that mediate these effects. In this study, we identified and characterized MTB lipoprotein Rv1016c (lpqT) as a cell wall associated-protein that was exposed on the cell surface and enhanced the survival of recombinants M. smegmatis_Rv1016c under stress conditions. We found that Rv1016c lipoprotein was a novel TLR2 ligand and able to induce macrophage apoptosis in a both dose- and time-dependent manner. Additionally, apoptosis induced by Rv1016c was reserved in THP-1 cells blocked with anti-TLR-2 Abs or in TLR2(-/-) mouse macrophages, indicating that Rv1016c-induced apoptosis is dependent on TLR2. Moreover, we demonstrated that Rv1016c lipoprotein inhibited IFN-γ-induced MHC-II expression and processing of soluble antigens in a TLR2 dependent manner. Class II transactivator (CIITA) regulates MHC II expression. In this context, Rv1016c lipoprotein diminished IFN-γ-induced expression of CIITA IV through TLR2 and MAPK Signaling. TLR2-dependent apoptosis and inhibition of MHC-II Ag processing induced by Rv1016c during mycobacteria infection may promote the release of residual bacilli from apoptotic cells and decrease recognition by CD4(+) T cells. These mechanisms may allow intracellular MTB to evade immune surveillance and maintain chronic infection.

  1. Target and resistance-related proteins of recombinant mutant human tumor necrosis factor-related apoptosis-inducing ligand on myeloma cell lines

    OpenAIRE

    JIAN, YUAN; Chen, Yuling; GENG, CHUANYING; Liu, Nian; YANG, GUANGZHONG; Liu, Jinwei; Li, Xin; Deng, Haiteng; CHEN, WENMING

    2016-01-01

    Recombinant mutant human tumor necrosis factor-related apoptosis-inducing ligand (rmhTRAIL) has become a potential therapeutic drug for multiple myeloma (MM). However, the exact targets and resistance mechanisms of rmhTRAIL on MM cells remain to be elucidated. The present study aimed to investigate the target and resistance-related proteins of rmhTRAIL on myeloma cell lines. A TRAIL-sensitive myeloma cell line, RPMI 8226, and a TRAIL-resistance one, U266, were chosen and the differentially ex...

  2. Potentiation of the teratogenic effects induced by coadministration of retinoic acid or phytanic acid/phytol with synthetic retinoid receptor ligands.

    Science.gov (United States)

    Elmazar, M M A; Nau, H

    2004-11-01

    Previous studies in our laboratory identified retinoid-induced defects that are mediated by RAR-RXR heterodimerization using interaction of synthetic ligands selective for the retinoid receptors RAR and RXR in mice (Elmazar et al. 1997, Toxicol Appl Pharmacol 146:21-28; Elmazar et al. 2001, Toxicol Appl Pharmacol 170:2-9; Nau and Elmazar 1999, Handbook of experimental pharmacology, vol 139, Retinoids, Springer-Verlag, pp 465-487). The present study was designed to investigate whether these RAR-RXR heterodimer-mediated defects can be also induced by interactions of natural and synthetic ligands for retinoid receptors. A non-teratogenic dose of the natural RXR agonist phytanic acid (100 mg/kg orally) or its precursor phytol (500 mg/kg orally) was coadministered with a synthetic RARalpha-agonist (Am580; 5 mg/kg orally) to NMRI mice on day 8.25 of gestation (GD8.25). Furthermore, a non-teratogenic dose of the synthetic RXR agonist LGD1069 (20 mg/kg orally) was also coadministered with the natural RAR agonist, all- trans-retinoic acid (atRA, 20 mg/kg orally) or its precursor retinol (ROH, 50 mg/kg orally) to NMRI mice on GD8.25. The teratogenic outcome was scored in day-18 fetuses. The incidence of Am580-induced resorptions, spina bifida aperta, micrognathia, anotia, kidney hypoplasia, dilated bladder, undescended testis, atresia ani, short and absent tail, fused ribs and fetal weight retardation were potentiated by coadministration of phytanic acid or its precursor phytol. Am580-induced exencephaly and cleft palate, which were not potentiated by coadministration with the synthetic RXR agonists, were also not potentiated by coadministration with either phytanic acid or its precursor phytol. LGD1069 potentiated atRA- and ROH-induced resorption, exencephaly, spina bifida, aperta, ear anotia and microtia, macroglossia, kidney hypoplasia, undescended testis, atresia ani, tail defects and fetal weight retardation, but not cleft palate. These results suggest that synergistic

  3. Platinum(II) phenanthroimidazole G-quadruplex ligand induces selective telomere shortening in A549 cancer cells.

    Science.gov (United States)

    Mancini, Johanna; Rousseau, Philippe; Castor, Katherine J; Sleiman, Hanadi F; Autexier, Chantal

    2016-02-01

    Telomere maintenance, achieved by the binding of protective shelterin capping proteins to telomeres and by either telomerase or a recombination-based alternative lengthening of telomere (ALT) mechanism, is critical for cell proliferation and survival. Extensive telomere shortening or loss of telomere integrity activates DNA damage checkpoints, leading to cell senescence or death. Although telomerase upregulation is an attractive target for anti-cancer therapy, the lag associated with telomere shortening and the potential activation of ALT pose a challenge. An alternative approach is to modify telomere interactions with binding proteins (telomere uncapping). G-quadruplex ligands stabilize structures generated from single-stranded G-rich 3'-telomere end (G-quadruplex) folding, which in principle, cannot be elongated by telomerase, thus leading to telomere shortening. Ligands can also mediate rapid anti-proliferative effects by telomere uncapping. We previously reported that the G-quadruplex ligand, phenylphenanthroimidazole ethylenediamine platinum(II) (PIP), inhibits telomerase activity in vitro[47]. In the current study, a long-term seeding assay showed that PIP significantly inhibited the seeding capacity of A549 lung cancer cells and to a lesser extent primary MRC5 fibroblast cells. Importantly, treatment with PIP caused a significant dose- and time-dependent decrease in average telomere length of A549 but not MRC5 cells. Moreover, cell cycle analysis revealed a significant increase in G1 arrest upon treatment of A549 cells, but not MRC5 cells. Both apoptosis and cellular senescence may contribute to the anti-proliferative effects of PIP. Our studies validate the development of novel and specific therapeutic ligands targeting telomeric G-quadruplex structures in cancer cells.

  4. Endogenous IGF-I and alpha v beta3 integrin ligands regulate increased smooth muscle growth in TNBS-induced colitis.

    Science.gov (United States)

    Hazelgrove, Krystina B; Flynn, Robert S; Qiao, Li-Ya; Grider, John R; Kuemmerle, John F

    2009-06-01

    Endogenous insulin-like growth factor-I (IGF-I) regulates intestinal smooth muscle growth by concomitantly stimulating proliferation and inhibiting apoptosis. IGF-I-stimulated growth is augmented by the alpha(v)beta(3) integrin ligands vitronectin and fibronectin. IGF-I expression in smooth muscle is increased in both TNBS-induced colitis and Crohn's disease. We hypothesized that intestinal inflammation increased vitronectin and fibronectin expression by smooth muscle and, along with IGF-I upregulation, increased intestinal muscle growth. Intestinal smooth muscle cells were examined 7 days following the induction of TNBS-induced colitis. Although alpha(v)beta(3) integrin expression was not altered by TNBS-induced colitis, vitronectin and fibronectin levels were increased by 80 +/- 10% and 90 +/- 15%, above control levels, respectively. Basal IGF-I receptor phosphorylation in inflamed muscle from TNBS-treated rats was increased by 86 +/- 8% over vehicle-treated controls. Basal ERK1/2, p70S6 kinase, and GSK-3beta phosphorylation in muscle cells of TNBS-treated rats were also increased by 140-180%. TNBS treatment increased basal muscle cell proliferation by 130 +/- 15% and decreased apoptosis by 20 +/- 2% compared with that in vehicle-treated controls. The changes in proliferation and apoptosis were reversed by an IGF-I receptor tyrosine kinase inhibitor or an alpha(v)beta(3) integrin antagonist. The results suggest that smooth muscle hyperplasia in TNBS-induced colitis partly results from the upregulation of endogenous IGF-I and ligands of alpha(v)beta(3) integrin that mediate increased smooth muscle cell proliferation and decreased apoptosis. This paper has identified one mechanism regulating smooth muscle hyperplasia, a feature of stricture formation that occurs in the chronically inflamed intestine of TNBS-induced colitis and potentially Crohn's disease.

  5. Enhancement of hypoxia-induced gene expression in fish liver by the aryl hydrocarbon receptor (AhR) ligand, benzo[a]pyrene (BaP).

    Science.gov (United States)

    Yu, Richard Man Kit; Ng, Patrick Kwok Shing; Tan, Tianfeng; Chu, Daniel Ling Ho; Wu, Rudolf Shiu Sun; Kong, Richard Yuen Chong

    2008-11-21

    Fish in polluted coastal habitats commonly suffer simultaneous exposure to both hypoxia and xenobiotics. Although the adaptive molecular responses to each stress have been described, little is known about the interaction between the signaling pathways mediating these responses. Previous studies in mammalian hepatoma cell lines have shown that hypoxia-inducible factor (HIF)- and/or aryl hydrocarbon receptor (AhR)-activated gene expression is suppressed following co-exposure to hypoxia and the hallmark AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, whether similar crosstalk exists in the non-tumor liver tissues of fish and whether other non-TCDD ligands also play the same inhibitory role in this crosstalk remain unknown. Here, the in vivo hepatic mRNA expression profiles of multiple hypoxia- and AhR-responsive genes (later gene expression=mRNA expression of the gene) were examined in the orange-spotted grouper (Epinephelus coioides) upon single and combined exposures to hypoxia and benzo[a]pyrene (BaP). Combined exposure enhanced hypoxia-induced gene expression but did not significantly alter BaP-induced gene expression. Protein carbonyl content was markedly elevated in fish subjected to combined exposure, indicating accumulation of reactive oxygen species (ROS). Application of diethyldithiocarbamate (DDC) to hypoxia-treated grouper liver explants similarly exaggerated hypoxia-induced gene expression as in the combined stress tissues in vivo. These observations suggest that ROS derived from the combined hypoxia and BaP stress have a role in enhancing hypoxia-induced gene expression.

  6. Full domain closure of the ligand-binding core of the ionotropic glutamate receptor iGluR5 induced by the high affinity agonist dysiherbaine and the functional antagonist 8,9-dideoxyneodysiherbaine

    DEFF Research Database (Denmark)

    Frydenvang, Karla Andrea; Lash, L Leanne; Naur, Peter

    2009-01-01

    The prevailing structural model for ligand activation of ionotropic glutamate receptors posits that agonist efficacy arises from the stability and magnitude of induced domain closure in the ligand-binding core structure. Here we describe an exception to the correlation between ligand efficacy...... and domain closure. A weakly efficacious partial agonist of very low potency for homomeric iGluR5 kainate receptors, 8,9-dideoxy-neodysiherbaine (MSVIII-19), induced a fully closed iGluR5 ligand-binding core. The degree of relative domain closure, ~30 degrees , was similar to that we resolved...... to inter-domain hydrogen bonds residues Glu441 and Ser721 in the iGluR5-S1S2 structure. The weaker interactions of MSVIII-19 with iGluR5 compared to DH, together with altered stability of the inter-domain interaction, may be responsible for the apparent uncoupling of domain closure and channel opening...

  7. Characterization of non-specific protein adsorption induced by triazole groups on the chromatography media using Cu (I)-catalyzed alkyne-azide cycloaddition reaction for ligand immobilization.

    Science.gov (United States)

    Gao, Ming; Ren, Jun; Tian, Kaikai; Jia, Lingyun

    2016-12-09

    As an efficient and facile reaction, click chemistry has been growingly used in the preparation of chromatography media for immobilizing varying types of ligands. For the widely used Cu (I)-catalyzed alkyne-azide click reaction, a 1, 2, 3-triazole group will be inevitably introduced in the molecular linkage, which could give rise to unexpected non-specific adsorption especially for the media employing small compound ligands or high ligand density. Triazole-induced non-specific protein adsorption on sepharose resins was evaluated systematically in this work, by considering the effects of triazole content, length of spacer arm, and solution conditions. We found that triazole content of a resin played the key role. Protein adsorption became significant when the media was coupled with triazole at a medium density (about 60μmol/mL gel), and the binding amount further increased with triazole density. The resin with triazole content of about 100μmol/mL gel could adsorb human IgG, bovine serum albumin and lysozyme at the amount of 13.6, 30.0, and 5.1mg/mL respectively. Proteins tended to be adsorbed at higher amount as the pH of solution approached their isoelectric points, and increasing salt concentration could reduce triazole-induced adsorption but only within limited extent. This study can facilitate reasonable application of click chemistry in the synthesis of chromatography media, by providing some basic principles for optimizing structural properties of separation media and choosing suitable solution conditions.

  8. Inositol hexaphosphate downregulates both constitutive and ligand-induced mitogenic and cell survival signaling, and causes caspase-mediated apoptotic death of human prostate carcinoma PC-3 cells.

    Science.gov (United States)

    Gu, Mallikarjuna; Raina, Komal; Agarwal, Chapla; Agarwal, Rajesh

    2010-01-01

    Constitutively active mitogenic and prosurvival signaling cascades due to aberrant expression and interaction of growth factors and their receptors are well documented in human prostate cancer (PCa). Epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1) are potent mitogens that regulate proliferation and survival of PCa cells via autocrine and paracrine loops involving both mitogen-activated protein kinase (MAPK)- and Akt-mediated signaling. Accordingly, here we assessed the effect of inositol hexaphosphate (IP6) on constitutive and ligand (EGF and IGF-1)-induced biological responses and associated signaling cascades in advanced and androgen-independent human PCa PC-3 cells. Treatment of PC-3 cells with 2 mM IP6 strongly inhibited both growth and proliferation and decreased cell viability; similar effects were also observed in other human PCa DU145 and LNCaP cells. IP6 also caused a strong apoptotic death of PC-3 cells together with caspase 3 and PARP cleavage. Mechanistic studies showed that biological effects of IP6 were associated with inhibition of both constitutive and ligand-induced Akt phosphorylation together with a decrease in total Akt levels, but a differential inhibitory effect on MAPKs extra cellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK1/2), and p38 under constitutive and ligand-activated conditions. Under similar condition, IP6 also inhibited AP-1 DNA-binding activity and decreased nuclear levels of both phospho and total c-Fos and c-Jun. Together, these findings for the first time establish IP6 efficacy in inhibiting aberrant EGF receptor (EGFR) or IGF-1 receptor (IGF-1R) pathway-mediated sustained growth promoting and survival signaling cascades in advanced and androgen-independent human PCa PC-3 cells, which might have translational implications in advanced human PCa control and management.

  9. Reduction of phosphorylated Thr-161 Cdk1 level participates in roscovitine-induced Fas ligand-mediated apoptosis in rat eggs cultured in vitro.

    Science.gov (United States)

    Tripathi, Anima; Chaube, Shail K

    2015-02-01

    The present study was aimed to find out whether roscovitine reduces phosphorylated Thr-161 of cyclin-dependent kinase 1 (Cdk1) level and induces egg apoptosis through Fas ligand (FasL)-mediated pathway. For this purpose, ovulated eggs were cultured in media 199 with or without various concentrations of roscovitine (0, 25, 50, 100, 200 μM) for 3 h in vitro. The morphological apoptotic changes, phosphorylation status of Cdk1, FasL concentration, caspase-8 and caspase-3 activities, and DNA fragmentation were analyzed. Data of the present study suggest that roscovitine significantly reduced Thr-161 phosphorylated Cdk1 level without altering the total level of Cdk1 and induced cytoplasmic fragmentation, a morphological apoptotic feature in a concentration-dependent manner. The roscovitine-induced cytoplasmic fragmentation was associated with increased FasL concentration. The increased FasL concentration induced caspase-8 followed by caspase-3 activities. The increased caspases activity finally induced DNA fragmentation in eggs that showed cytoplasmic fragmentation. Taken together, these results suggest that roscovitine reduced phosphorylated Thr-161 of Cdk1 level and induces apoptosis through FasL-mediated pathway in rat eggs cultured in vitro.

  10. Mixed-ligand copper(II) complexes activate aryl hydrocarbon receptor AhR and induce CYP1A genes expression in human hepatocytes and human cell lines.

    Science.gov (United States)

    Kubešová, Kateřina; Dořičáková, Aneta; Trávníček, Zdeněk; Dvořák, Zdeněk

    2016-07-25

    The effects of four copper(II) mixed-ligand complexes [Cu(qui1)(L)]NO3·H2O (1-3) and [Cu(qui2)(phen)]NO3 (4), where qui1=2-phenyl-3-hydroxy-4(1H)-quinolinone, Hqui2=2-(4-amino-3,5-dichlorophenyl)-N-propyl-3-hydroxy-4(1H)-quinolinone-7-carboxamide, L=1,10-phenanthroline (phen) (1), 5-methyl-1,10-phenanthroline (mphen) (2), bathophenanthroline (bphen) (3), on transcriptional activities of steroid receptors, nuclear receptors and xenoreceptors have been studied. The complexes (1-4) did not influence basal or ligand-inducible activities of glucocorticoid receptor, androgen receptor, thyroid receptor, pregnane X receptor and vitamin D receptor, as revealed by gene reporter assays. The complexes 1 and 2 dose-dependently induced luciferase activity in stable gene reporter AZ-AhR cell line, and this induction was reverted by resveratrol, indicating involvement of aryl hydrocarbon receptor (AhR) in the process. The complexes 1, 2 and 3 induced CYP1A1 mRNA in LS180 cells and CYP1A1/CYP1A2 in human hepatocytes through AhR. Electrophoretic mobility shift assay EMSA showed that the complexes 1 and 2 transformed AhR in its DNA-binding form. Collectively, we demonstrate that the complexes 1 and 2 activate AhR and induce AhR-dependent genes in human hepatocytes and cancer cell lines. In conclusion, the data presented here might be of toxicological importance, regarding the multiple roles of AhR in human physiology and pathophysiology.

  11. Combined treatment with the Cox-2 inhibitor niflumic acid and PPARγ ligand ciglitazone induces ER stress/caspase-8-mediated apoptosis in human lung cancer cells.

    Science.gov (United States)

    Kim, Byeong Mo; Maeng, Kyungah; Lee, Kee-Ho; Hong, Sung Hee

    2011-01-28

    The present study was performed to investigate the possible combined use of the Cox-2 inhibitor niflumic acid and the PPARγ ligand ciglitazone and to elucidate the mechanisms underlying enhanced apoptosis by this combination treatment in human lung cancer cells. Combined niflumic acid-ciglitazone treatment synergistically induced apoptotic cell death, activated caspase-9, caspase-3, and induced caspase-3-mediated PARP cleavage. The combination treatment also triggered apoptosis through caspase-8/Bid/Bax activation, and the inhibition of caspase-8 suppressed caspase-8/Bid activation, caspase-3-mediated PARP cleavage, and concomitant apoptosis. In addition, combined niflumic acid-ciglitazone treatment significantly induced ER stress responses, and suppression of CHOP expression significantly attenuated the combined niflumic acid-ciglitazone treatment-induced activation of caspase-8 and caspase-3, and the subsequent apoptotic cell death, indicating a role of ER stress in caspase-8 activation and apoptosis. Interestingly, the pro-apoptotic effects of combined niflumic acid-ciglitazone treatment were realized through Cox-2- and PPARγ-independent mechanisms. Taken together, these results suggest that sequential ER stress and caspase-8 activation are critical in combined niflumic acid-ciglitazone treatment-induced apoptosis in human lung cancer cells.

  12. Immunization with HBsAg-Fc fusion protein induces a predominant production of Th1 cytokines and reduces HBsAg level in transgenic mice

    Institute of Scientific and Technical Information of China (English)

    MENG Zhe-feng; WANG Hua-jing; YAO Xin; WANG Xuan-yi; WEN Yu-mei; DAI Jian-xin; XIE You-hua; XU Jian-qing

    2012-01-01

    Background The Fc receptor associated pathway might improve the immune responses against hepatitis B virus (HBV) as previously described by us.In addition,the Flt3 ligand (FL) has been reported to potentiate antigen presenting cells in vivo and may act as a potential adjuvant to boost antigen-specific immune responses.In this study,the immune efficacies of a set of fusion proteins of HBsAg and Fc and/or FL were evaluated in HBsAg transgenic mice.Methods The fusion proteins composed of HBsAg and the Fc domain of murine IgG1 (HBsAg-Fc) and/or the Flt3 ligand,and yeast-derived recombinant HBsAg were used as immunogen to immunize HBsAg transgenic mice,respectively.Serum and liver HBsAg levels,serum anti-HBsAg and cytokine profile,and the activities of alanine aminotransferase (ALT)/AST were investigated after immunization.Results After six injections,the most pronounced decrease in serum and liver HBsAg levels was observed in the HBsAg-Fc immunized group.In addition,serum Th1 cytokines and ALT/AST activities were highest in this group,indicating an effective induction of a favorable cellular immune response.Interestingly,the fusion protein containing HBsAg-Fc and the Flt3 ligand stimulated an alternative Th1-type immune response featured with high level productions of tumor necrosis factor α (TNF- α) and monocyte chemoabstractant protein 1 (MCP-1),causing a more severe cytotoxicity in hepatocytes while showed less effective in reducing serum HBsAg level.Conclusion HBsAg-Fc is effective in eliciting both the humoral and cellular immune responses against HBsAg in HBsAg transgenic mice,which makes it a potential immunogen for the immunotherapy of chronic hepatitis B.

  13. Essential roles of the CC chemokine ligand 3-CC chemokine receptor 5 axis in bleomycin-induced pulmonary fibrosis through regulation of macrophage and fibrocyte infiltration.

    Science.gov (United States)

    Ishida, Yuko; Kimura, Akihiko; Kondo, Toshikazu; Hayashi, Takahito; Ueno, Masaya; Takakura, Nobuyuki; Matsushima, Kouji; Mukaida, Naofumi

    2007-03-01

    We investigated the pathogenic roles of CC chemokine ligand (CCL)3 and its receptors, CC chemokine receptor (CCR)1 and CCR5, in bleomycin (BLM)-induced pulmonary fibrosis (PF). An intratracheal injection of BLM into wild-type (WT) mice caused a massive infiltration of granulocytes and macrophages, followed by the development of diffuse PF with fibrocyte accumulation. Intrapulmonary CCL3 expression was enhanced rapidly and remained at elevated levels until PF developed. Moreover, CCL3 protein was detected mainly in infiltrating granulocytes and macrophages, whereas transforming growth factor-beta1 protein was detected in macrophages and myofibroblasts. Compared with WT mice, collagen accumulation was reduced in CCL3(-/-) and CCR5(-/-) but not CCR1(-/-) mice. Moreover, the BLM-induced increases in intrapulmonary macrophage and fibrocyte numbers were attenuated in CCL3(-/-) and CCR5(-/-) but not CCR1(-/-) mice, although BLM increased bone marrow (BM) fibrocyte number to a similar extent in these strains. BM transplantation from CCR5(-/-) to WT, but not that from WT to CCR5(-/-) mice, recapitulated the phenotypes in CCR5(-/-) mice. Furthermore, CCR5(+/-) mice exhibited a significant reduction in BLM-induced fibrotic changes. These results demonstrated that locally produced CCL3 was involved in BLM-induced recruitment of BM-derived macrophages and fibrocytes, main producers of transforming growth factor-beta1, and subsequent development of PF by interacting mainly with CCR5.

  14. Mutation-induced quisqualic acid and ibotenic acid affinity at the metabotropic glutamate receptor subtype 4: ligand selectivity results from a synergy of several amino acid residues

    DEFF Research Database (Denmark)

    Hermit, Mette B; Greenwood, Jeremy R; Bräuner-Osborne, Hans

    2004-01-01

    resides. In this study, we have identified four non-conserved amino acid residues that are essential for differentiating mGluR1 from mGluR4. Our approach has been to increase the affinity of the classic mGluR1 agonists, quisqualic acid and ibotenic acid, at mGluR4 by making various point mutations...... that mimicked mGluR1 residues. Based on ligand docking to homology models, the non-conserved residues, Lys-74, Glu-287, Ser-313, and Lys-317, were chosen for the mutational studies and all of the mutations proved capable of partially or completely restoring the affinities of the ligands. In particular......, the mutations K74Y and K317R induced dramatic triple-order-of-magnitude increases in the affinity of ibotenic acid at mGluR4, making the affinity equivalent to that of mGluR1. Furthermore, the affinity of quisqualic acid at mGluR4 was increased to the same level as mGluR1 by the two double mutations, K74Y/K317R...

  15. PolyA-tailed and fluorophore-labeled aptamer-gold nanoparticle conjugate for fluorescence turn-on bioassay using iodide-induced ligand displacement.

    Science.gov (United States)

    Li, Wei; Dong, Yifan; Wang, Xi; Li, Hui; Xu, Danke

    2015-04-15

    Depending on the strong affinity of polyA sequence to gold (or silver) surface, applicability of polyA-tailed DNA-gold (or silver) nanoparticle conjugates in homogeneous and heterogeneous protein assays was first demonstrated. Interestingly, when using polyA-tailed, fluophore-labeled DNA-AuNP conjugate, it was found that iodide and thiosulfate anions could act as the ligand displacing reagent to detach polyA-tailed DNA strands from AuNP surface and simultaneously activate the AuNP-quenched fluorophores by destroying the polyA-AuNP interaction via a divide-and-conquer strategy. Based on this new discovery, we have developed a novel, cost-effective and sandwich-type fluorescence turn-on aptasensor for highly sensitive and specific thrombin detection, what took advantage of aptamer-conjugated magnetic beads (apt-MBs) for protein capture and separation, and iodide-induced fluorescence recovery of activatable polyA-based AuNP probes through ligand displacement for fluorescence turn-on detection. This proposed aptasensor could detect thrombin specifically with a detection limit as low as 89pM, which was better than or comparable to many existing fluorescent thrombin assays. Importantly, employment of such polyA-based AuNP conjugate not only avoids the use of thiolated oligonucleotides and thiol-containing displacing reagents, but also offers new possibilities for fabricating convenient and cost-effective bioanalytical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Exposure of cultured fibroblasts to the peptide PR-11 for the identification of induced proteome alterations and discovery of novel potential ligands.

    Science.gov (United States)

    Breguez, Gustavo Silveira; Neves, Leandro Xavier; Silva, Karina Taciana Santos; de Freitas, Lorran Miranda Andrade; de Oliveira Faria, Gabriela; Isoldi, Mauro César; Castro-Borges, William; de Andrade, Milton Hércules Guerra

    2016-12-01

    The PR-11 peptide corresponds to the N-terminal and active region of the endogenously synthesized PR-39 molecule, of porcine origin. It is known to possess various biological effects including antimicrobial properties, angiogenic and anti-inflammatory activities. Apart from its reported activity as a proteasome inhibitor, a more comprehensive understanding of its function, at the molecular level, is still lacking. In this study, we used a label-free shotgun strategy to evaluate the proteomic alterations caused by exposure of cultured fibroblasts to the peptide PR-11. This approach revealed that more than half of the identified molecules were related to signalling, transcription and translation. Proteins directly associated to regulation of angiogenesis and interaction with the hypoxia-inducible factor 1-α (HIF-1α) were significantly altered. In addition, at least three differentially expressed molecules of the NF-κB pathway were detected, suggesting an anti-inflammatory property of PR-11. At last, we demonstrated novel potential ligands of PR-11, through its immobilization for affinity chromatography. Among the eluted molecules, gC1qR, a known complement receptor, appeared markedly enriched. This provided preliminary evidence of a PR-11 ligand possibly involved in the internalization of this peptide. Altogether, our findings contributed to a better understanding of the cellular pathways affected by PR-39 derived molecules. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. It's all about Me: methyl-induced control of coordination stereochemistry by a flexible tridentate N,C,N' ligand.

    Science.gov (United States)

    Kariuki, Benson M; Platts, James A; Newman, Paul D

    2014-02-21

    A chiral, tridentate, pyridyl-functionalised NHC pro-ligand, S-L(Me)-H[PF₆], has been prepared diastereoselectively via a five step synthesis starting from 1R,3S-diamino-1,2,2-trimethylcyclopentane. The S prefix refers to the stereochemistry of a methyl substituted stereogenic carbon in one of the pyridyl arms which is generated by a stereoselective BH4(-) reduction of an imine precursor. The ligand has been coordinated to Rh(I) and Ir(I) to give trigonal bipyramidal complexes of the type [M(κ(3)-N,C,N'-S-L(Me))(1,5-COD)]PF6 (M = Rh, Ir) as single diastereomers. A combination of spectroscopic and X-ray techniques confirm the stereoselective formation of the thermodynamically preferred endo,endo isomer. Similar reactions with R,S-L(Me)-H[PF₆] gave a mixture of endo,endo-[M(κ(3)-N,C,N'-S-L(Me))(1,5-COD)](+) and exo,exo-[M(κ(3)-N,C,N'-R-L(Me))(1,5-COD)](+). The absolute configuration at the metal is, therefore, solely dictated by the stereochemistry of the single methylpyridyl carbon. The observation of stereoselection extends to the square planar Ni(II) complex [Ni(δ-κ(3)-N,C,N'-S-L(Me))Cl](+) which is isolated as one (δ) of the two possible conformational isomers. DFT studies have been employed to explain the observed stereoselectivity with the configurations observed in the solid state being confirmed as those of lowest energy.

  18. ADAM10 mediates the house dust mite-induced release of chemokine ligand CCL20 by airway epithelium

    NARCIS (Netherlands)

    Post, S.; Rozeveld, D.; Jonker, M. R.; Bischoff, R.; van Oosterhout, A. J.; Heijink, I. H.

    2015-01-01

    Background: House dust mite (HDM) acts on the airway epithelium to induce airway inflammation in asthma. We previously showed that the ability of HDM to induce allergic sensitization in mice is related to airway epithelial CCL20 secretion. Objective: As a disintegrin and metalloprotease (ADAM)s have

  19. Combining ligand-induced quantum-confined stark effect with type II heterojunction bilayer structure in CdTe and CdSe nanocrystal-based solar cells.

    Science.gov (United States)

    Yaacobi-Gross, Nir; Garphunkin, Natalia; Solomeshch, Olga; Vaneski, Aleksandar; Susha, Andrei S; Rogach, Andrey L; Tessler, Nir

    2012-04-24

    We show that it is possible to combine several charge generation strategies in a single device structure, the performance of which benefits from all methods used. Exploiting the inherent type II heterojunction between layered structures of CdSe and CdTe colloidal quantum dots, we systematically study different ways of combining such nanocrystals of different size and surface chemistry and with different linking agents in a bilayer solar cell configuration. We demonstrate the beneficial use of two distinctly different sizes of NCs not only to improve the solar spectrum matching but also to reduce exciton binding energy, allowing their efficient dissociation at the interface. We further make use of the ligand-induced quantum-confined Stark effect in order to enhance charge generation and, hence, overall efficiency of nanocrystal-based solar cells.

  20. From mixed to three-layer core/shell PtCu nanoparticles: ligand-induced surface segregation to enhance electrocatalytic activity.

    Science.gov (United States)

    Dai, Changqing; Yang, Yang; Zhao, Zheng; Fisher, Adrian; Liu, Zhiping; Cheng, Daojian

    2017-07-06

    Core-shell segregated bimetallic nanoparticles (NPs) exhibit increased enhanced catalytic performance compared to that of mixed bimetallic NPs. Here, we report a simple, yet efficient, one-pot synthetic strategy to synthesize uniform three-layer core/shell PtCu NPs by adding benzyl ether (BE) in the synthesis process of mixed PtCu NPs. In comparison with commercial Pt/C and also mixed PtCu NPs, the three-layer core/shell PtCu NPs exhibit superior activity in catalyzing the oxygen reduction reaction (ORR), formic acid oxidation reaction (FAOR), methanol oxidation reaction (MOR), and ethanol oxidation reaction (EOR), mainly due to the ligand (BE)-induced surface segregation of Pt on the surface of the NPs.

  1. The role of neutrophils and TNF-related apoptosis-inducing ligand (TRAIL) in bacillus Calmette-Guérin (BCG) immunotherapy for urothelial carcinoma of the bladder.

    Science.gov (United States)

    Rosevear, Henry M; Lightfoot, Andrew J; O'Donnell, Michael A; Griffith, Thomas S

    2009-12-01

    Intravesical Mycobacterium bovis bacillus Calmette-Guérin (BCG) immunotherapy is a highly effective treatment for carcinoma in situ of the bladder, as well as high-risk nonmuscle invasive urothelial carcinoma of the bladder. Despite over 30 years of clinical experience with BCG, the therapy's mechanism has remained enigmatic. Observations regarding the role of neutrophils in BCG immunotherapy have led to exciting discoveries regarding the potential role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in creating the therapeutic benefit of BCG immunotherapy. In this paper, we will review the scope of the disease, highlight our understanding of the role for BCG in urothelial carcinoma of the bladder, explain the recent discoveries regarding the role of neutrophils and TRAIL in therapy, and theorize on potential future areas of research.

  2. Pan-HER - an antibody mixture targeting EGFR, HER2, and HER3 abrogates preformed and ligand-induced EGFR homo- and heterodimers

    DEFF Research Database (Denmark)

    Ellebaek, Sofie; Pedersen, Susanne Brix; Grandal, Michael

    2016-01-01

    Abs is development of acquired resistance through mechanisms such as alterated receptor dimerization patterns and dependencies. Pan-HER is a mixture of six mAbs simultaneously targeting epidermal growth factor receptor (EGFR), HER2, and HER3 with two mAbs against each receptor. Pan-HER has previously demonstrated....... The effect of Pan-HER on cell proliferation and HER-family receptor degradation was superior to treatment with single mAbs targeting either single receptor, and similar to targeting a single receptor with two non-overlapping antibodies. Furthermore, changes in EGFR-dimerization patterns after treatment......-HER and the EGFR-targeting mAb mixture also blocked EGF-binding and thereby ligand-induced changes in EGFR-dimerization levels. These results suggest that Pan-HER reduces the cellular capability to switch HER-dependency and dimerization pattern in response to treatment and thus hold promise for future clinical...

  3. Suppressive effect of pioglitazone, a PPAR gamma ligand, on azoxymethane-induced colon aberrant crypt foci in KK-Ay mice.

    Science.gov (United States)

    Ueno, Toshiya; Teraoka, Naoya; Takasu, Shinji; Nakano, Katsuya; Takahashi, Mami; Yamamoto, Masafumi; Fujii, Gen; Komiya, Masami; Yanaka, Akinori; Wakabayashi, Keiji; Mutoh, Michihiro

    2012-01-01

    Obesity is an established risk factor for colorectal cancer. Pioglitazone is a peroxisome proliferator- activated receptor γ(PPARγ) agonist that induces differentiation in adipocytes and induces growth arrest and/or apoptosis in vitro in several cancer cell lines. In the present study, we investigated the effect of pioglitazone on the development of azoxymethane-induced colon aberrant crypt foci (ACF) in KK-Ay obesity and diabetes model mice, and tried to clarify mechanisms by which the PPARγ ligand inhibits ACF development. Administration of 800 ppm pioglitazone reduced the number of colon ACF / mouse to 30% of those in untreated mice and improved hypertrophic changes of adipocytes in KK-Ay mice with significant reduction of serum triglyceride and insulin levels. Moreover, mRNA levels of adipocytokines, such as leptin, monocyte chemoattractant protein-1 and plasminogen activator inhibitor-1, in the visceral fat were decreased. PCNA immunohistochemistry revealed that pioglitazone treatment suppressed cell proliferation in the colorectal epithelium with elevation of p27 and p53 gene expression. These results suggest that pioglitazone prevented obesity-associated colon carcinogenesis through improvement of dysregulated adipocytokine levels and high serum levels of triglyceride and insulin, and increase of p27 and p53 mRNA levels in the colorectal mucosa. These data indicate that pioglitazone warrants attention as a potential chemopreventive agent against obesity-associated colorectal cancer.

  4. RIAM, an Ena/VASP and Profilin ligand, interacts with Rap1-GTP and mediates Rap1-induced adhesion.

    Science.gov (United States)

    Lafuente, Esther M; van Puijenbroek, André A F L; Krause, Matthias; Carman, Christopher V; Freeman, Gordon J; Berezovskaya, Alla; Constantine, Erica; Springer, Timothy A; Gertler, Frank B; Boussiotis, Vassiliki A

    2004-10-01

    The small GTPase Rap1 induces integrin-mediated adhesion and changes in the actin cytoskeleton. The mechanisms that mediate these effects of Rap1 are poorly understood. We have identified RIAM as a Rap1-GTP-interacting adaptor molecule. RIAM defines a family of adaptor molecules that contain a RA-like (Ras association) domain, a PH (pleckstrin homology) domain, and various proline-rich motifs. RIAM also interacts with Profilin and Ena/VASP proteins, molecules that regulate actin dynamics. Overexpression of RIAM induced cell spreading and lamellipodia formation, changes that require actin polymerization. In contrast, RIAM knockdown cells had reduced content of polymerized actin. RIAM overexpression also induced integrin activation and cell adhesion. RIAM knockdown displaced Rap1-GTP from the plasma membrane and abrogated Rap1-induced adhesion. Thus, RIAM links Rap1 to integrin activation and plays a role in regulating actin dynamics.

  5. AcEST: DK959440 [AcEST

    Lifescience Database Archive (English)

    Full Text Available ine-induced protein 16 OS=Schizosacch... 32 1.3 sp|P49771|FLT3L_HUMAN SL cytokine OS=Homo sapiens GN=FLT3LG ...RKCVIGIKSFEKLQSYVFTYYCERYPKLIL 826 >sp|P49771|FLT3L_HUMAN SL cytokine OS=Homo sapiens GN=FLT3LG PE=1 SV=1 Le

  6. Protection of radiation-induced damage to the hematopoietic system, small intestine and salivary glands in rats by JNJ7777120 compound, a histamine H4 ligand.

    Directory of Open Access Journals (Sweden)

    Diego J Martinel Lamas

    Full Text Available Based on previous data on the histamine radioprotective effect on highly radiosensitive tissues, in the present work we aimed at investigating the radioprotective potential of the H4R ligand, JNJ7777120, on ionizing radiation-induced injury and genotoxic damage in small intestine, salivary glands and hematopoietic tissue. For that purpose, rats were divided into 4 groups. JNJ7777120 and JNJ7777120-irradiated groups received a daily subcutaneous JNJ7777120 injection (10 mg/kg starting 24 h before irradiation. Irradiated groups received a single dose of 5 Gy on whole-body using Cesium-137 source and were sacrificed 3 or 30 days after irradiation. Tissues were removed, fixed, stained with hematoxylin and eosin or PAS staining and histological characteristics were evaluated. Proliferative and apoptotic markers were studied by immunohistochemistry, while micronucleus assay was performed to evaluate DNA damage. Submandibular gland (SMG function was evaluated by methacholine-induced salivation. Results indicate that JNJ7777120 treatment diminished mucosal atrophy and preserved villi and the number of crypts after radiation exposure (240±8 vs. 165±10, P<0.01. This effect was associated to a reduced apoptosis and DNA damage in intestinal crypts. JNJ7777120 reduced radiation-induced aplasia, preserving medullar components and reducing formation of micronucleus and also it accelerated bone marrow repopulation. Furthermore, it reduced micronucleus frequency in peripheral blood (27±8 vs. 149±22, in 1,000 erythrocytes, P<0.01. JNJ7777120 completely reversed radiation-induced reduced salivation, conserving glandular mass with normal histological appearance and reducing apoptosis and atrophy of SMG. JNJ7777120 exhibits radioprotective effects against radiation-induced cytotoxic and genotoxic damages in small intestine, SMG and hematopoietic tissues and, thus, could be of clinical value for patients undergoing radiotherapy.

  7. Recombinant human endostatin inhibits TNF-alpha-induced receptor activator of NF-κB ligand expression in fibroblast-like synoviocytes in mice with adjuvant arthritis.

    Science.gov (United States)

    Gao, Qiu-Fang; Zhang, Xiu-Hong; Yuan, Feng-Lai; Zhao, Ming-Dong; Li, Xia

    2016-12-01

    Bone loss is a critical pathology responsible for the functional disability in patients with rheumatoid arthritis (RA). It is well known that receptor activator of nuclear factor kappa-B (NF-κB) ligand (RANKL) plays a crucial role in bone loss in RA. The purpose of this study was to determine whether recombinant human endostatin (rh-endostatin) mediates bone erosion in RA by regulation of RANKL expression in an experimental model of RA, consisting of mice with adjuvant-induced arthritis (AA). Cultured AA fibroblast-like synoviocytes (FLSs) obtained from these mice were induced by tumor necrosis factor-α (TNF-α) combined with or without rh-endostatin. The levels of RANKL and osteoprotegerin (OPG) mRNA, soluble and membrane-bound proteins were assessed by real-time PCR, ELISA, and Western blotting. Western blotting and the luciferase reporter assay were used to study related signaling pathways. Rh-endostatin inhibited RANKL mRNA expression, soluble and membrane-bound protein expression in AA FLSs but not in CD4+ T cells. However, OPG expression and secretion was not affected by rh-endostatin in AA FLSs. Molecular analysis demonstrated that rh-endostatin significantly inhibited TNF-α-induced MAPK and AP-1 signaling pathways. Moreover, rh-endostatin attenuated TNF-α-induced NF-κB signaling by suppressing the phosphorylation level of inhibitor kappaBα (IκBα) and nuclear translocation of NF-κB p65 in FLSs from mice with AA. These results provide the first evidence that rh-endostatin inhibits TNF-α-induced RANKL expression in AA FLSs.

  8. Induction of apoptosis in osteogenic sarcoma cells by combination of tumor necrosis factor-related apoptosis inducing ligand and chemotherapeutic agents

    Institute of Scientific and Technical Information of China (English)

    SUN Jie; FU Zhi-min; FANG Chang-qing; LI Jian-hua

    2007-01-01

    Background Osteosarcoma is one of the most common primary malignant tumors of bone with poor prognosis.TNF-related apoptosis inducing ligand (TRAIL) is a member of the tumor necrosis factor (TNF) cytokine family. TRAIL induces apoptosis in various tumor cell lines but is not found to be cytotoxic to many normal cell types in vitro. We investigated the cytotoxic activity of TRAIL and chemotherapeutic agents, including methotrexate (MTX), doxorubicin(DOX) and cisplatin (CDDP), on established osteosarcoma cell line-OS-732.Methods OS-732 cells were incubated with chemotherapeutic agents MTX,DOX and CDDP at various peak plasma concentrations(PPC), 0.1PPC,1PPC and 10PPC, alone or with 100 ng/ml of TRAIL for 24 hours or 48 hours. MTT was used to evaluate the cytotoxic activity of different agents on OS-732. The apoptosis proportion was assayed by flow cytometry. Cellular morphologic changes were observed by phase contrast microscope, scan electron microscope, and transmission electron microscope.Results The inhibitory rate was (24.438±3.414)% with TRAIL of 100 ng/ml for 24 hours. The cells were responsive to DOX and CDDP with a dose-effect relationship (P<0.05). In OS-732 cells, DOX and CDDP cooperated synergistically with TRAIL when incubated the cells with them for 24 hours (the combined inhibitory rate is (58.360±2.146)% and (54.101 ±2.721)%, respectively). TRAIL alone or drugs alone induced the apoptosis rate was less than 25% (P<0.05).However, the combination of TRAIL and MTX did not present synergistic effects on OS-732 cells (P>0.05, compared with TRAIL alone).Conclusions Osteosarcoma OS-732 cells were not responsive to TRAIL-induced apoptosis. DOX and CDDP sensitize osteosarcoma OS-732 cells to TRAIL-induced apoptosis. The combination of TRAIL and MTX presented no synergistic effects on killing OS-732 cells.

  9. Heparan sulfate acts as a bone morphogenetic protein coreceptor by facilitating ligand-induced receptor hetero-oligomerization.

    Science.gov (United States)

    Kuo, Wan-Jong; Digman, Michelle A; Lander, Arthur D

    2010-11-15

    Cell surface heparan sulfate (HS) not only binds several major classes of growth factors but also sometimes potentiates their activities--an effect usually termed "coreception." A view that coreception is due to the stabilization of growth factor-receptor interactions has emerged primarily from studies of the fibroblast growth factors (FGFs). Recent in vivo studies have strongly suggested that HS also plays an important role in regulating signaling by the bone morphogenetic proteins (BMPs). Here, we provide evidence that the mechanism of coreception for BMPs is markedly different from that established for FGFs. First, we demonstrate a direct, stimulatory role for cell surface HS in the immediate signaling activities of BMP2 and BMP4, and we provide evidence that HS-BMP interactions are required for this effect. Next, using several independent assays of ligand binding and receptor assembly, including coimmunoprecipitation, cross-linking, and fluorescence fluctuation microscopy, we show that HS does not affect BMP binding to type I receptor subunits but instead enhances the subsequent recruitment of type II receptor subunits to BMP-type I receptor complexes. This suggests a view of HS as a catalyst of the formation of signaling complexes, rather than as a stabilizer of growth factor binding.

  10. Type 2 innate lymphoid cell suppression by regulatory T cells attenuates airway hyperreactivity and requires inducible T-cell costimulator-inducible T-cell costimulator ligand interaction.

    Science.gov (United States)

    Rigas, Diamanda; Lewis, Gavin; Aron, Jennifer L; Wang, Bowen; Banie, Homayon; Sankaranarayanan, Ishwarya; Galle-Treger, Lauriane; Maazi, Hadi; Lo, Richard; Freeman, Gordon J; Sharpe, Arlene H; Soroosh, Pejman; Akbari, Omid

    2017-05-01

    Atopic diseases, including asthma, exacerbate type 2 immune responses and involve a number of immune cell types, including regulatory T (Treg) cells and the emerging type 2 innate lymphoid cells (ILC2s). Although ILC2s are potent producers of type 2 cytokines, the regulation of ILC2 activation and function is not well understood. In the present study, for the first time, we evaluate how Treg cells interact with pulmonary ILC2s and control their function. ILC2s and Treg cells were evaluated by using in vitro suppression assays, cell-contact assays, and gene expression panels. Also, human ILC2s and Treg cells were adoptively transferred into NOD SCID γC-deficient mice, which were given isotype or anti-inducible T-cell costimulator ligand (ICOSL) antibodies and then challenged with IL-33 and assessed for airway hyperreactivity. We show that induced Treg cells, but not natural Treg cells, effectively suppress the production of the ILC2-driven proinflammatory cytokines IL-5 and IL-13 both in vitro and in vivo. Mechanistically, our data reveal the necessity of inducible T-cell costimulator (ICOS)-ICOS ligand cell contact for Treg cell-mediated ILC2 suppression alongside the suppressive cytokines TGF-β and IL-10. Using a translational approach, we then demonstrate that human induced Treg cells suppress syngeneic human ILC2s through ICOSL to control airway inflammation in a humanized ILC2 mouse model. These findings suggest that peripheral expansion of induced Treg cells can serve as a promising therapeutic target against ILC2-dependent asthma. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  11. Dietary Flavonoids Sensitize HeLa Cells to Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL

    Directory of Open Access Journals (Sweden)

    Wojciech Król

    2008-01-01

    Full Text Available TRAIL is a promising candidate for cancer therapeutics that preferentially induces apoptosis in cancer cells. The combined treatment flavonoids with TRAIL might be promising as a chemoprevention and/or new therapy against malignant tumors. We examined the cytotoxic effect of dietary flavonoids in combination with TRAIL on HeLa cells. It was found that treatment with noncytotoxic concentration of some flavonoids significantly sensititizes to TRAIL induced death in HeLa cells. Our study demonstrated that flavone, apigenin and genistein markedly augmented TRAIL mediated cytotoxicity against HeLa, whereas kaempferol and quercetin produced no effect.

  12. Dietary flavonoids sensitize HeLa cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).

    Science.gov (United States)

    Szliszka, Ewelina; Czuba, Zenon P; Jernas, Katarzyna; Król, Wojciech

    2008-01-01

    TRAIL is a promising candidate for cancer therapeutics that preferentially induces apoptosis in cancer cells. The combined treatment flavonoids with TRAIL might be promising as a chemoprevention and/or new therapy against malignant tumors. We examined the cytotoxic effect of dietary flavonoids in combination with TRAIL on HeLa cells. It was found that treatment with noncytotoxic concentration of some flavonoids significantly sensititizes to TRAIL induced death in HeLa cells. Our study demonstrated that flavone, apigenin and genistein markedly augmented TRAIL mediated cytotoxicity against HeLa, whereas kaempferol and quercetin produced no effect.

  13. Cell surface-bound TIMP3 induces apoptosis in mesenchymal Cal78 cells through ligand-independent activation of death receptor signaling and blockade of survival pathways.

    Directory of Open Access Journals (Sweden)

    Christina Koers-Wunrau

    Full Text Available BACKGROUND: The matrix metalloproteinases (MMPs and their endogenous regulators, the tissue inhibitor of metalloproteinases (TIMPs 1-4 are responsible for the physiological remodeling of the extracellular matrix (ECM. Among all TIMPs, TIMP3 appears to play a unique role since TIMP3 is a secreted protein and, unlike the other TIMP family members, is tightly bound to the ECM. Moreover TIMP3 has been shown to be able to induce apoptotic cell death. As little is known about the underlying mechanisms, we set out to investigate the pro-apoptotic effect of TIMP3 in human mesenchymal cells. METHODOLOGY/PRINCIPAL FINDINGS: Lentiviral overexpression of TIMP3 in mesenchymal cells led to a strong dose-dependent induction of ligand-independent apoptosis as reflected by a five-fold increase in caspase 3 and 7 activity compared to control (pLenti6/V5-GW/lacZ or uninfected cells, whereas exogenous TIMP3 failed to induce apoptosis. Concordantly, increased cleavage of death substrate PARP and the caspases 3 and 7 was observed in TIMP3 overexpressing cultures. Notably, activation of caspase-8 but not caspase-9 was observed in TIMP3-overexpressing cells, indicating a death receptor-dependent mechanism. Moreover, overexpression of TIMP3 led to a further induction of apoptosis after stimulation with TNF-alpha, FasL and TRAIL. Most interestingly, TIMP3-overexpression was associated with a decrease in phosphorylation of cRaf, extracellular signal-regulated protein kinase (Erk1/2, ribosomal S6 kinase (RSK1 and Akt and serum deprivation of TIMP3-overexpressing cells resulted in a distinct enhancement of apoptosis, pointing to an impaired signaling of serum-derived survival factors. Finally, heparinase treatment of heparan sulfate proteoglycans led to the release of TIMP3 from the surface of overexpressing cells and to a significant decrease in apoptosis indicating that the binding of TIMP3 is necessary for apoptosis induction. CONCLUSION: The results demonstrate that

  14. Bryostatin-1, a naturally occurring antineoplastic agent, acts as a Toll-like receptor 4 (TLR-4) ligand and induces unique cytokines and chemokines in dendritic cells.

    Science.gov (United States)

    Ariza, Maria Eugenia; Ramakrishnan, Rupal; Singh, Narendra P; Chauhan, Ashok; Nagarkatti, Prakash S; Nagarkatti, Mitzi

    2011-01-07

    Bryostatin-1 (Bryo-1), a natural macrocyclic lactone, is clinically used as an anti-cancer agent. In this study, we demonstrate for the first time that Bryo-1 acts as a Toll-like receptor 4 (TLR4) ligand. Interestingly, activation of bone marrow-derived dendritic cells (in vitro with Bryo-1) led to a TLR4-dependent biphasic activation of nuclear factor-κB (NF-κB) and the unique induction of cytokines (IL-5, IL-6, and IL-10) and chemokines, including RANTES (regulated on activation normal T cell expressed and secreted) and macrophage inflammatory protein 1α (MIP1-α). In addition, EMSA demonstrated that Bryo-1-mediated induction of RANTES was regulated by NF-κB and the interferon regulatory factors (IRF)-1, IRF-3, and IRF-7 to the RANTES independently of myeloid differentiation primary response gene-88 (MyD88). Bryo-1 was able to induce the transcriptional activation of IRF-3 through the TLR4/MD2-dependent pathway. In vivo administration of Bryo-1 triggered a TLR-4-dependent T helper cell 2 (Th2) cytokine response and expanded a subset of myeloid dendritic cells that expressed a CD11c(high)CD8α(-) CD11b(+)CD4(+) phenotype. This study demonstrates that Bryo-1 can act as a TLR4 ligand and activate innate immunity. Moreover, the ability of Bryo-1 to trigger RANTES and MIP1-α suggests that Bryo-1 could potentially be used to prevent HIV-1 infection. Finally, induction of a Th2 response by Bryo-1 may help treat inflammatory diseases mediated by Th1 cells. Together, our studies have a major impact on the clinical use of Bryo-1 as an anti-cancer and immunopotentiating agent.

  15. A Fusion Protein between Streptavidin and the Endogenous TLR4 Ligand EDA Targets Biotinylated Antigens to Dendritic Cells and Induces T Cell Responses In Vivo

    Directory of Open Access Journals (Sweden)

    Laura Arribillaga

    2013-01-01

    Full Text Available The development of tools for efficient targeting of antigens to antigen presenting cells is of great importance for vaccine development. We have previously shown that fusion proteins containing antigens fused to the extra domain A from fibronectin (EDA, an endogenous TLR4 ligand, which targets antigens to TLR4-expressing dendritic cells (DC, are highly immunogenic. To facilitate the procedure of joining EDA to any antigen of choice, we have prepared the fusion protein EDAvidin by linking EDA to the N terminus of streptavidin, allowing its conjugation with biotinylated antigens. We found that EDAvidin, as streptavidin, forms tetramers and binds biotin or biotinylated proteins with a Kd ~ 2.6 × 10−14 mol/L. EDAvidin favours the uptake of biotinylated green fluorescent protein by DC. Moreover, EDAvidin retains the proinflammatory properties of EDA, inducing NF-κβ by TLR4-expressing cells, as well as the production of TNF-α by the human monocyte cell line THP1 and IL-12 by DC. More importantly, immunization of mice with EDAvidin conjugated with the biotinylated nonstructural NS3 protein from hepatitis C virus induces a strong anti-NS3 T cell immune response. These results open a new way to use the EDA-based delivery tool to target any antigen of choice to DC for vaccination against infectious diseases and cancer.

  16. Receptor Activator of Nuclear Factor κB Ligand (RANKL) Protein Expression by B Lymphocytes Contributes to Ovariectomy-induced Bone Loss*

    Science.gov (United States)

    Onal, Melda; Xiong, Jinhu; Chen, Xinrong; Thostenson, Jeff D.; Almeida, Maria; Manolagas, Stavros C.; O'Brien, Charles A.

    2012-01-01

    Production of the cytokine receptor activator of NFκB ligand (RANKL) by lymphocytes has been proposed as a mechanism by which sex steroid deficiency causes bone loss. However, there have been no studies that functionally link RANKL expression in lymphocytes with bone loss in this condition. Herein, we examined whether RANKL expression in either B or T lymphocytes contributes to ovariectomy-induced bone loss in mice. Mice harboring a conditional RANKL allele were crossed with CD19-Cre or Lck-Cre mice to delete RANKL in B or T lymphocytes, respectively. Deletion of RANKL from either cell type had no impact on bone mass in estrogen-replete mice up to 7 months of age. However, mice lacking RANKL in B lymphocytes were partially protected from the bone loss caused by ovariectomy. This protection occurred in cancellous, but not cortical, bone and was associated with a failure to increase osteoclast numbers in the conditional knock-out mice. Deletion of RANKL from T lymphocytes had no impact on ovariectomy-induced bone loss. These results demonstrate that lymphocyte RANKL is not involved in basal bone remodeling, but B cell RANKL does contribute to the increase in osteoclasts and cancellous bone loss that occurs after loss of estrogen. PMID:22782898

  17. Antibody ligation of CM1 on cisplatin-exposed HeLa cells induces apoptosis through reactive oxygen species-dependent Fas ligand expression.

    Science.gov (United States)

    Park, Ga Bin; Kim, Daejin; Yoon, Hoi Soo; Kim, Yeong-Seok; Lee, Hyun-Kyung; Kim, Ki Tae; Jeong, Dae Hoon; Hur, Dae Young

    2014-06-01

    Centrocyte/centroblast marker 1 (CM1) has been identified as a pro-apoptosis molecule on B-cell lymphoma cells as well as several types of cancer cells. In this study, we investigated its signaling mechanism in HeLa cells after treatment with cisplatin in order to potentially identify a new therapeutic target. The CM1 molecule was induced on the surface of cisplatin-exposed HeLa cells. In these cells, ligation of CM1 with anti-CM1 monoclonal antibodies inhibited cell proliferation and produced reactive oxygen species. Fas ligand (FasL) expression was upregulated without upregulating Fas in cisplatin-exposed HeLa cells after CM1 stimulation. Pretreatment with N-acetylcysteine, a pan-capase inhibitor, and ZB4, an antagonistic anti-Fas antibody, effectively inhibited the apoptotic effect triggered by CM1. CM1 ligation induced apoptosis through disruption of the mitochondrial membrane potential, decreased Bcl-2 and phosphorylated ERK expression. These findings identify CM1 as a potential new therapeutic target related to cisplatin-exposed cervical cancer.

  18. Antiosteoclastogenesis activity of a CO2 laser antagonizing receptor activator for nuclear factor kappaB ligand-induced osteoclast differentiation of murine macrophages

    Science.gov (United States)

    Kuo, Chun-Liang; Kao, Chia-Tze; Fang, Hsin-Yuan; Huang, Tsui-Hsien; Chen, Yi-Wen; Shie, Ming-You

    2015-03-01

    Macrophage cells are the important effector cells in the immune reaction which are indispensable for osteoclastogenesis; their heterogeneity and plasticity renders macrophages a primer target for immune system modulation. In recent years, there have been very few studies about the effects of macrophage cells on laser treatment-regulated osteoclastogenesis. In this study, RAW 264.7 macrophage cells were treated with RANKL to regulate osteoclastogenesis. We used a CO2 laser as a model biostimulation to investigate the role of osteoclastogenic. We also evaluated cell viability, cell death and cathepsin K expression. The CO2 laser inhibited a receptor activator of the NF-ĸB ligand (RANKL)-induced formation of osteoclasts during the osteoclast differentiation process. It was also found that irradiation for two times reduced RANKL-enhanced TRAP activity in a dose-dependent manner. Furthermore, CO2 laser-treatment diminished the expression and secretion of cathepsin K elevated by RANKL and was concurrent with the inhibition of TRAF6 induction and NF-ĸB activation. The current report demonstrates that CO2 laser abrogated RANKL-induced osteoclastogenesis by retarding osteoclast differentiation. The CO2 laser can modulate every cell through dose-dependent in vitro RANKL-mediated osteoclastogenesis, such as the proliferation and fusion of preosteoclasts and the maturation of osteoclasts. Therefore, the current results serve as an improved explanation of the cellular roles of macrophage cell populations in osteoclastogenesis as well as in alveolar bone remodeling by CO2 laser-treatment.

  19. Benzimidazoisoquinolines: a new class of rapidly metabolized aryl hydrocarbon receptor (AhR ligands that induce AhR-dependent Tregs and prevent murine graft-versus-host disease.

    Directory of Open Access Journals (Sweden)

    Sumit Punj

    Full Text Available The aryl hydrocarbon receptor (AhR is a ligand-activated transcription factor that plays multiple roles in regulation of immune and inflammatory responses. The ability of certain AhR ligands to induce regulatory T cells (Tregs has generated interest in developing AhR ligands for therapeutic treatment of immune-mediated diseases. To this end, we designed a screen for novel Treg-inducing compounds based on our understanding of the mechanisms of Treg induction by the well-characterized immunosuppressive AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD. We screened a ChemBridge small molecule library and identified 10-chloro-7H-benzimidazo[2,1-a]benzo[de]Iso-quinolin-7-one (10-Cl-BBQ as a potent AhR ligand that was rapidly metabolized and not cytotoxic to proliferating T cells. Like TCDD,10-Cl-BBQ altered donor CD4(+ T cell differentiation during the early stages of a graft versus host (GVH response resulting in expression of high levels of CD25, CTLA-4 and ICOS, as well as several genes associated with Treg function. The Treg phenotype required AhR expression in the donor CD4(+ T cells. Foxp3 was not expressed in the AhR-induced Tregs implicating AhR as an independent transcription factor for Treg induction. Structure-activity studies showed that unsubstituted BBQ as well as 4, 11-dichloro-BBQ were capable of inducing AhR-Tregs. Other substitutions reduced activation of AhR. Daily treatment with 10-Cl-BBQ during the GVH response prevented development of GVH disease in an AhR-dependent manner with no overt toxicity. Together, our data provide strong support for development of select BBQs that activate the AhR to induce Tregs for treatment of immune-mediated diseases.

  20. 7,12-Dimethylbenzanthracene induces apoptosis in RL95-2 human endometrial cancer cells: Ligand-selective activation of cytochrome P450 1B1

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Young [Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, Busan 602-714 (Korea, Republic of); Medical Research Science Center, Dong-A University, Busan 602-714 (Korea, Republic of); Lee, Seung Gee [Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, Busan 602-714 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Chung, Jin-Yong [Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, Busan 602-714 (Korea, Republic of); Medical Research Science Center, Dong-A University, Busan 602-714 (Korea, Republic of); Kim, Yoon-Jae [Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, Busan 602-714 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Park, Ji-Eun [Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, Busan 602-714 (Korea, Republic of); Medical Research Science Center, Dong-A University, Busan 602-714 (Korea, Republic of); Oh, Seunghoon [Department of Physiology, College of Medicine, Dankook University, Cheonan 330-714 (Korea, Republic of); Lee, Se Yong [Department of Obstetrics and Gynecology, Busan Medical Center, Busan 611-072 (Korea, Republic of); Choi, Hong Jo [Department of General Surgery, College of Medicine, Dong-A University, Busan 602-714 (Korea, Republic of); Yoo, Young Hyun, E-mail: yhyoo@dau.ac.kr [Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, Busan 602-714 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Medical Research Science Center, Dong-A University, Busan 602-714 (Korea, Republic of); and others

    2012-04-15

    7,12-Dimethylbenzanthracene (DMBA), a polycyclic aromatic hydrocarbon, exhibits mutagenic, carcinogenic, immunosuppressive, and apoptogenic properties in various cell types. To achieve these functions effectively, DMBA is modified to its active form by cytochrome P450 1 (CYP1). Exposure to DMBA causes cytotoxicity-mediated apoptosis in bone marrow B cells and ovarian cells. Although uterine endometrium constitutively expresses CYP1A1 and CYP1B1, their apoptotic role after exposure to DMBA remains to be elucidated. Therefore, we chose RL95-2 endometrial cancer cells as a model system for studying DMBA-induced cytotoxicity and cell death and hypothesized that exposure to DMBA causes apoptosis in this cell type following CYP1A1 and/or CYP1B1 activation. We showed that DMBA-induced apoptosis in RL95-2 cells is associated with activation of caspases. In addition, mitochondrial changes, including decrease in mitochondrial potential and release of mitochondrial cytochrome c into the cytosol, support the hypothesis that a mitochondrial pathway is involved in DMBA-induced apoptosis. Exposure to DMBA upregulated the expression of AhR, Arnt, CYP1A1, and CYP1B1 significantly; this may be necessary for the conversion of DMBA to DMBA-3,4-diol-1,2-epoxide (DMBA-DE). Although both CYP1A1 and CYP1B1 were significantly upregulated by DMBA, only CYP1B1 exhibited activity. Moreover, knockdown of CYP1B1 abolished DMBA-induced apoptosis in RL95-2 cells. Our data show that RL95-2 cells are susceptible to apoptosis by exposure to DMBA and that CYP1B1 plays a pivotal role in DMBA-induced apoptosis in this system. -- Highlights: ► Cytotoxicity-mediated apoptogenic action of DMBA in human endometrial cancer cells. ► Mitochondrial pathway in DMBA-induced apoptosis of RL95-2 endometrial cancer cells. ► Requirement of ligand-selective activation of CYP1B1 in DMBA-induced apoptosis.

  1. The GPCR-associated sorting protein 1 regulates ligand-induced down-regulation of GPR55.

    Science.gov (United States)

    Kargl, J; Balenga, N A; Platzer, W; Martini, L; Whistler, J L; Waldhoer, M

    2012-04-01

    Many GPCRs, including the CB(1) cannabinoid receptor, are down-regulated following prolonged agonist exposure by interacting with the GPCR-associated sorting protein-1 (GASP-1). The CB(1) receptor antagonist rimonabant has also recently been described to be an agonist at GPR55, a cannabinoid-related receptor. Here we investigated the post-endocytic properties of GPR55 after agonist exposure and tested whether GASP-1 is involved in this process. We evaluated the direct protein-protein interaction of GPR55 with GASP-1 using (i) GST-binding assays and (ii) co-immunoprecipitation assays in GPR55-HEK293 cells with endogenous GASP-1 expression. We further tested the internalization, recycling and degradation of GPR55 using confocal fluorescence microscopy and biotinylation assays in the presence and absence of GASP-1 (lentiviral small hairpin RNA knockdown of GASP-1) under prolonged agonist [rimonabant (RIM), lysophosphatidylinositol (LPI)] stimulation. We showed that the prolonged activation of GPR55 with rimonabant or LPI down-regulates GPR55 via GASP-1. GASP-1 binds to GPR55 in vitro, and this interaction was required for targeting GPR55 for degradation. Disrupting the GPR55-GASP-1 interaction prevented post-endocytic receptor degradation, and thereby allowed receptor recycling. These data implicate GASP-1 as an important regulator of ligand-mediated down-regulation of GPR55. By identifying GASP-1 as a key regulator of the trafficking and, by extension, functional expression of GPR55, we may be one step closer to gaining a better understanding of this receptor in response to cannabinoid drugs. This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological

  2. The Fas/Fas ligand death receptor pathway contributes to phenylalanine-induced apoptosis in cortical neurons.

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    Xiaodong Huang

    Full Text Available Phenylketonuria (PKU, an autosomal recessive disorder of amino acid metabolism caused by mutations in the phenylalanine hydroxylase (PAH gene, leads to childhood mental retardation by exposing neurons to cytotoxic levels of phenylalanine (Phe. A recent study showed that the mitochondria-mediated (intrinsic apoptotic pathway is involved in Phe-induced apoptosis in cultured cortical neurons, but it is not known if the death receptor (extrinsic apoptotic pathway and endoplasmic reticulum (ER stress-associated apoptosis also contribute to neurodegeneration in PKU. To answer this question, we used specific inhibitors to block each apoptotic pathway in cortical neurons under neurotoxic levels of Phe. The caspase-8 inhibitor Z-IETD-FMK strongly attenuated apoptosis in Phe-treated neurons (0.9 mM, 18 h, suggesting involvement of the Fas receptor (FasR-mediated cell death receptor pathway in Phe toxicity. In addition, Phe significantly increased cell surface Fas expression and formation of the Fas/FasL complex. Blocking Fas/FasL signaling using an anti-Fas antibody markedly inhibited apoptosis caused by Phe. In contrast, blocking the ER stress-induced cell death pathway with salubrinal had no effect on apoptosis in Phe-treated cortical neurons. These experiments demonstrate that the Fas death receptor pathway contributes to Phe-induced apoptosis and suggest that inhibition of the death receptor pathway may be a novel target for neuroprotection in PKU patients.

  3. Aryl Hydrocarbon Receptor Ligands in Cigarette Smoke Induce Production of Interleukin-22 to Promote Pancreatic Fibrosis in Models of Chronic Pancreatitis.

    Science.gov (United States)

    Xue, Jing; Zhao, Qinglan; Sharma, Vishal; Nguyen, Linh P; Lee, Yvonne N; Pham, Kim L; Edderkaoui, Mouad; Pandol, Stephen J; Park, Walter; Habtezion, Aida

    2016-12-01

    Cigarette smoke has been identified as an independent risk factor for chronic pancreatitis (CP). Little is known about the mechanisms by which smoking promotes development of CP. We assessed the effects of aryl hydrocarbon receptor (AhR) ligands found in cigarette smoke on immune cell activation in humans and pancreatic fibrosis in animal models of CP. We obtained serum samples from patients with CP treated at Stanford University hospital and healthy individuals (controls) and isolated CD4(+) T cells. Levels of interleukin-22 (IL22) were measured by enzyme-linked immunosorbent assay and smoking histories were collected. T cells from healthy nonsmokers and smokers were stimulated and incubated with AhR agonists (2,3,7,8-tetrachlorodibenzo-p-dioxin or benzo[a]pyrene) or antagonists and analyzed by flow cytometry. Mice were given intraperitoneal injections of caerulein or saline, with or without lipopolysaccharide, to induce CP. Some mice were given intraperitoneal injections of AhR agonists at the start of caerulein injection, with or without an antibody against IL22 (anti-IL22) starting 2 weeks after the first caerulein injection, or recombinant mouse IL22 or vehicle (control) intraperitoneally 4 weeks after the first caerulein injection. Mice were exposed to normal air or cigarette smoke for 6 h/d for 7 weeks and expression of AhR gene targets was measured. Pancreata were collected from all mice and analyzed by histology and quantitative reverse transcription polymerase chain reaction. Pancreatic stellate cells and T cells were isolated and studied using immunoblot, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent analyses. Mice given AhR agonists developed more severe pancreatic fibrosis (based on decreased pancreas size, histology, and increased expression of fibrosis-associated genes) than mice not given agonists after caerulein injection. In mice given saline instead of caerulein, AhR ligands did not induce fibrosis. Pancreatic T cells

  4. Propofol Binding to the Resting State of the Gloeobacter violaceus Ligand-gated Ion Channel (GLIC) Induces Structural Changes in the Inter- and Intrasubunit Transmembrane Domain (TMD) Cavities*

    Science.gov (United States)

    Ghosh, Borna; Satyshur, Kenneth A.; Czajkowski, Cynthia

    2013-01-01

    General anesthetics exert many of their CNS actions by binding to and modulating membrane-embedded pentameric ligand-gated ion channels (pLGICs). The structural mechanisms underlying how anesthetics modulate pLGIC function remain largely unknown. GLIC, a prokaryotic pLGIC homologue, is inhibited by general anesthetics, suggesting anesthetics stabilize a closed channel state, but in anesthetic-bound GLIC crystal structures the channel appears open. Here, using functional GLIC channels expressed in oocytes, we examined whether propofol induces structural rearrangements in the GLIC transmembrane domain (TMD). Residues in the GLIC TMD that frame intrasubunit and intersubunit water-accessible cavities were individually mutated to cysteine. We measured and compared the rates of modification of the introduced cysteines by sulfhydryl-reactive reagents in the absence and presence of propofol. Propofol slowed the rate of modification of L240C (intersubunit) and increased the rate of modification of T254C (intrasubunit), indicating that propofol binding induces structural rearrangements in these cavities that alter the local environment near these residues. Propofol acceleration of T254C modification suggests that in the resting state propofol does not bind in the TMD intrasubunit cavity as observed in the crystal structure of GLIC with bound propofol (Nury, H., Van Renterghem, C., Weng, Y., Tran, A., Baaden, M., Dufresne, V., Changeux, J. P., Sonner, J. M., Delarue, M., and Corringer, P. J. (2011) Nature 469, 428–431). In silico docking using a GLIC closed channel homology model suggests propofol binds to intersubunit sites in the TMD in the resting state. Propofol-induced motions in the intersubunit cavity were distinct from motions associated with channel activation, indicating propofol stabilizes a novel closed state. PMID:23640880

  5. TNF-Related Apoptosis-Inducing Ligand (TRAIL)-Armed Exosomes Deliver Proapoptotic Signals to Tumor Site.

    Science.gov (United States)

    Rivoltini, Licia; Chiodoni, Claudia; Squarcina, Paola; Tortoreto, Monica; Villa, Antonello; Vergani, Barbara; Bürdek, Maja; Botti, Laura; Arioli, Ivano; Cova, Agata; Mauri, Giorgio; Vergani, Elisabetta; Bianchi, Beatrice; Della Mina, Pamela; Cantone, Laura; Bollati, Valentina; Zaffaroni, Nadia; Gianni, Alessandro Massimo; Colombo, Mario Paolo; Huber, Veronica

    2016-07-15

    Exosomes deliver signals to target cells and could thus be exploited as an innovative therapeutic tool. We investigated the ability of membrane TRAIL-armed exosomes to deliver proapoptotic signals to cancer cells and mediate growth inhibition in different tumor models. K562 cells, transduced with lentiviral human membrane TRAIL, were used for the production of TRAIL(+) exosomes, which were studied by nanoparticle tracking analysis, cytofluorimetry, immunoelectronmicroscopy, Western blot, and ELISA. In vitro, TRAIL(+) exosomes induced more pronounced apoptosis (detected by Annexin V/propidium iodide and activated caspase-3) in TRAIL-death receptor (DR)5(+) cells (SUDHL4 lymphoma and INT12 melanoma), with respect to the DR5(-)DR4(+)KMS11 multiple myeloma. Intratumor injection of TRAIL(+) exosomes, but not mock exosomes, induced growth inhibition of SUDHL4 (68%) and INT12 (51%), and necrosis in KMS11 tumors. After rapid blood clearance, systemically administered TRAIL(+) exosomes accumulated in the liver, lungs, and spleen and homed to the tumor site, leading to a significant reduction of tumor growth (58%) in SUDHL4-bearing mice. The treatment of INT12-bearing animals promoted tumor necrosis and a not statistically significant tumor volume reduction. In KMS11-bearing mice, despite massive perivascular necrosis, no significant tumor growth inhibition was detected. TRAIL-armed exosomes can induce apoptosis in cancer cells and control tumor progression in vivo Therapeutic efficacy was particularly evident in intratumor setting, while depended on tumor model upon systemic administration. Thanks to their ability to deliver multiple signals, exosomes thus represent a promising therapeutic tool in cancer. Clin Cancer Res; 22(14); 3499-512. ©2016 AACR. ©2016 American Association for Cancer Research.

  6. Presenilin mediates neuroprotective functions of ephrinB and brain-derived neurotrophic factor and regulates ligand-induced internalization and metabolism of EphB2 and TrkB receptors.

    Science.gov (United States)

    Barthet, Gael; Dunys, Julie; Shao, Zhiping; Xuan, Zhao; Ren, Yimin; Xu, Jindong; Arbez, Nicolas; Mauger, Gweltas; Bruban, Julien; Georgakopoulos, Anastasios; Shioi, Junichi; Robakis, Nikolaos K

    2013-02-01

    Activation of EphB receptors by ephrinB (efnB) ligands on neuronal cell surface regulates important functions, including neurite outgrowth, axonal guidance, and synaptic plasticity. Here, we show that efnB rescues primary cortical neuronal cultures from necrotic cell death induced by glutamate excitotoxicity and that this function depends on EphB receptors. Importantly, the neuroprotective function of the efnB/EphB system depends on presenilin 1 (PS1), a protein that plays crucial roles in Alzheimer's disease (AD) neurodegeneration. Furthermore, absence of one PS1 allele results in significantly decreased neuroprotection, indicating that both PS1 alleles are necessary for full expression of the neuroprotective activity of the efnB/EphB system. We also show that the ability of brain-derived neurotrophic factor (BDNF) to protect neuronal cultures from glutamate-induced cell death depends on PS1. Neuroprotective functions of both efnB and BDNF, however, were independent of γ-secretase activity. Absence of PS1 decreases cell surface expression of neuronal TrkB and EphB2 without affecting total cellular levels of the receptors. Furthermore, PS1-knockout neurons show defective ligand-dependent internalization and decreased ligand-induced degradation of TrkB and Eph receptors. Our data show that PS1 mediates the neuroprotective activities of efnB and BDNF against excitotoxicity and regulates surface expression and ligand-induced metabolism of their cognate receptors. Together, our observations indicate that PS1 promotes neuronal survival by regulating neuroprotective functions of ligand-receptor systems.

  7. Expression of TNF-related apoptosis-inducing ligand (TRAIL in keratinocytes mediates apoptotic cell death in allogenic T cells

    Directory of Open Access Journals (Sweden)

    Kiefer Paul

    2009-11-01

    Full Text Available Abstract The objective of the present study was to evaluate the aptitude of TRAIL gene expression for inducing apoptosis in co-cultivated T-cells. This should allow preparing a strategy for the development of a durable, allogenic skin substitute based on the induction of an immune-privileged transplant. In order to counteract the significant potential of rejection in transplanted allogenic keratinocytes, we created a murine keratinocyte cell line which expressed TRAIL through stable gene transfer. The exogenic protein was localized on the cellular surface and was not found in soluble condition as sTRAIL. Contact to TRAIL expressing cells in co-culture induced cell death in sensitive Jurkat-cells, which was further intensified by lymphocyte activation. This cytotoxic effect is due to the induction of apoptosis. We therefore assume that the de-novo expression of TRAIL in keratinocytes can trigger apoptosis in activated lymphocytes and thus prevent the rejection of keratinocytes in allogenic, immune-privileged transplants.

  8. Valence Tautomerization of High-Valent Manganese(V)-Oxo Corrole Induced by Protonation of the Oxo Ligand.

    Science.gov (United States)

    Bougher, Curt J; Liu, Shuo; Hicks, Scott D; Abu-Omar, Mahdi M

    2015-11-18

    The addition of an organic acid to the manganese(V)-oxo corrole complex (tpfc)Mn(V)(O) (tpfc = 5,10,15-tris(pentafluorophenyl)corrole) induces valence tautomerization resulting in the formation of (tpfc(+•))Mn(IV)(OH) in acetonitrile at 298 K. The corrole radical cation manganese(IV) hydroxo complex has been fully characterized by EPR, (1)H NMR, and UV-vis spectroscopy. The reactivity of the valence tautomer (tpfc(+•))Mn(IV)(OH) is compared to that of (tpfc)Mn(V)(O) in three reaction types: hydrogen atom transfer (HAT), electron transfer (ET), and oxygen atom transfer (OAT). (tpfc(+•))Mn(IV)(OH) shows a dramatic 5 orders of magnitude enhancement in the rate of ET but surprisingly does not undergo OAT with PhSMe. The high-valent (tpfc)Mn(V)(O) complex is moderately more reactive toward HAT with substituted phenol and shows superior activity in OAT.

  9. Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand-Induced Apoptosis in Prostate Cancer Cells after Treatment with Xanthohumol-A Natural Compound Present in Humulus lupulus L.

    Science.gov (United States)

    Kłósek, Małgorzata; Mertas, Anna; Król, Wojciech; Jaworska, Dagmara; Szymszal, Jan; Szliszka, Ewelina

    2016-06-22

    TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is an endogenous ligand, which plays role in immune surveillance and anti-tumor immunity. It has ability to selectively kill tumor cells showing no toxicity to normal cells. We tested the apoptotic and cytotoxic activities of xanthohumol, a prenylated chalcone found in Humulus lupulus on androgen-sensitive human prostate adenocarcinoma cells (LNCaP) in combination with TRAIL. Cytotoxicity was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reduction assay (MTT) and lactate dehydrogenase assay (LDH). The expression of death receptors (DR4/TRAIL-R1 and DR5/TRAIL-R2) and apoptosis were detected using flow cytometry. We examined mitochondrial membrane potential (ΔΨm) by DePsipher reagent using fluorescence microscopy. The intracellular expression of proteins was evaluated by Western blotting. Our study showed that xanthohumol enhanced cytotoxic and apoptotic effects of TRAIL. The tested compounds activated caspases-3, -8, -9, Bid, and increased the expression of Bax. They also decreased expression of Bcl-xL and decreased mitochondrial membrane potential, while the expression of death receptors was not changed. The findings suggest that xanthohumol is a compound of potential use in chemoprevention of prostate cancer due to its sensitization of cancer cells to TRAIL-mediated apoptosis.

  10. Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand-Induced Apoptosis in Prostate Cancer Cells after Treatment with Xanthohumol—A Natural Compound Present in Humulus lupulus L.

    Directory of Open Access Journals (Sweden)

    Małgorzata Kłósek

    2016-06-01

    Full Text Available TRAIL (tumor necrosis factor-related apoptosis-inducing ligand is an endogenous ligand, which plays role in immune surveillance and anti-tumor immunity. It has ability to selectively kill tumor cells showing no toxicity to normal cells. We tested the apoptotic and cytotoxic activities of xanthohumol, a prenylated chalcone found in Humulus lupulus on androgen-sensitive human prostate adenocarcinoma cells (LNCaP in combination with TRAIL. Cytotoxicity was measured by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide tetrazolium reduction assay (MTT and lactate dehydrogenase assay (LDH. The expression of death receptors (DR4/TRAIL-R1 and DR5/TRAIL-R2 and apoptosis were detected using flow cytometry. We examined mitochondrial membrane potential (ΔΨm by DePsipher reagent using fluorescence microscopy. The intracellular expression of proteins was evaluated by Western blotting. Our study showed that xanthohumol enhanced cytotoxic and apoptotic effects of TRAIL. The tested compounds activated caspases-3, -8, -9, Bid, and increased the expression of Bax. They also decreased expression of Bcl-xL and decreased mitochondrial membrane potential, while the expression of death receptors was not changed. The findings suggest that xanthohumol is a compound of potential use in chemoprevention of prostate cancer due to its sensitization of cancer cells to TRAIL-mediated apoptosis.

  11. Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand-Induced Apoptosis in Prostate Cancer Cells after Treatment with Xanthohumol—A Natural Compound Present in Humulus lupulus L.

    Science.gov (United States)

    Kłósek, Małgorzata; Mertas, Anna; Król, Wojciech; Jaworska, Dagmara; Szymszal, Jan; Szliszka, Ewelina

    2016-01-01

    TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) is an endogenous ligand, which plays role in immune surveillance and anti-tumor immunity. It has ability to selectively kill tumor cells showing no toxicity to normal cells. We tested the apoptotic and cytotoxic activities of xanthohumol, a prenylated chalcone found in Humulus lupulus on androgen-sensitive human prostate adenocarcinoma cells (LNCaP) in combination with TRAIL. Cytotoxicity was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reduction assay (MTT) and lactate dehydrogenase assay (LDH). The expression of death receptors (DR4/TRAIL-R1 and DR5/TRAIL-R2) and apoptosis were detected using flow cytometry. We examined mitochondrial membrane potential (ΔΨm) by DePsipher reagent using fluorescence microscopy. The intracellular expression of proteins was evaluated by Western blotting. Our study showed that xanthohumol enhanced cytotoxic and apoptotic effects of TRAIL. The tested compounds activated caspases-3, -8, -9, Bid, and increased the expression of Bax. They also decreased expression of Bcl-xL and decreased mitochondrial membrane potential, while the expression of death receptors was not changed. The findings suggest that xanthohumol is a compound of potential use in chemoprevention of prostate cancer due to its sensitization of cancer cells to TRAIL-mediated apoptosis. PMID:27338375

  12. Insertion of the CXC chemokine ligand 9 (CXCL9) into the mouse hepatitis virus genome results in protection from viral-induced encephalitis and hepatitis.

    Science.gov (United States)

    Muse, Michael; Kane, Joy A C; Carr, Daniel J J; Farber, Joshua M; Lane, Thomas E

    2008-12-20

    The role of the CXC chemokine ligand 9 (CXCL9) in host defense following infection with mouse hepatitis virus (MHV) was determined. Inoculation of the central nervous system (CNS) of CXCL9-/- mice with MHV resulted in accelerated and increased mortality compared to wild type mice supporting an important role for CXCL9 in anti-viral defense. In addition, infection of RAG1-/- or CXCL9-/- mice with a recombinant MHV expressing CXCL9 (MHV-CXCL9) resulted in protection from disease that correlated with reduced viral titers within the brain and NK cell-mediated protection in the liver. Survival in MHV-CXCL9-infected CXCL9-/- mice was associated with reduced viral burden within the brain that coincided with increased T cell infiltration. Similarly, viral clearance from the livers of MHV-CXCL9-infected mice was accelerated but independent of increased T cell or NK cell infiltration. These observations indicate that CXCL9 promotes protection from coronavirus-induced neurological and liver disease.

  13. Does DcR1 (TNF-related apoptosis-inducing-ligand Receptor 3) have any role in human AMD pathogenesis?

    Science.gov (United States)

    Anand, Akshay; Sharma, Neel K; Singh, Ramandeep; Gupta, Amod; Prabhakar, Sudesh; Jindal, Neeru; Bhatt, Arvind K; Sharma, Suresh K; Gupta, Pawan K

    2014-02-18

    It has been postulated that there is a link between age related degenerative diseases and cancer. The TNF-related apoptosis-inducing ligand (TRAIL) has been shown to selectively kill tumor cells by binding to pro-apoptotic and anti-apoptotic receptors. Our aim was to study the levels of anti-apoptotic receptor (DcR1) in age related macular degeneration (AMD) and controls. AMD patients (115) were classified into two groups: Dry and Wet AMD. Wet AMDs were further classified into occult, predominant classic and minimal classic. 61 healthy individuals were recruited as normal controls. After normalization with total protein, DcR1 levels were analyzed by ELISA. Mann Whitney U-statistic was used for analysis of DcR1 ELISA results. We have observed DcR1 levels in serum sample which were significantly lower in AMD patients as compared to controls (p = 0.001). On the other hand, we did not find difference in DcR1 levels between wet and dry AMD. The present study defines the plausible role of DcR1 in AMD pathology signifying a new therapeutic target for AMD.

  14. Antibodies to P-selectin glycoprotein ligand-1 block dendritic cell-mediated enterovirus 71 transmission and prevent virus-induced cells death.

    Science.gov (United States)

    Ren, Xiao-Xin; Li, Chuan; Xiong, Si-Dong; Huang, Zhong; Wang, Jian-Hua; Wang, Hai-Bo

    2015-01-01

    P-selectin glycoprotein ligand-1 (PSGL-1) has been proved to serve as the functional receptor for enterovirus 71 (EV71). We found the abundant expression of PSGL-1 on monocyte-derived dendritic cells (MDDCs). However, we have previously demonstrated that MDDCs did not support efficient replication of EV71. Dendritic cells (DCs) have been described to be subverted by various viruses including EV71 for viral dissemination, we thus explore the potential contribution of PSGL-1 on DC-mediated EV71 transmission. We found that the cell-surface-expressing PSGL-1 on MDDCs mediated EV71 binding, and intriguingly, these loaded-viruses on MDDCs could be transferred to encountered target cells; Prior-treatment with PSGL-1 antibodies or interference with PSGL-1 expression diminished MDDC-mediated EV71 transfer and rescued virus-induced cell death. Our data uncover a novel role of PSGL-1 in DC-mediated EV71 spread, and provide an insight into blocking primary EV71 infection.

  15. Supra-additive antitumor activity of 5FU with tumor necrosis factor-related apoptosis-inducing ligand on gastric and colon cancers in vitro.

    Science.gov (United States)

    Shimoyama, Shouji; Mochizuki, Yoshino; Kusada, Osamu; Kaminishi, Michio

    2002-09-01

    We investigated supra-additive cytotoxic effects of 5-fluorouracil (5FU) on gastric and colon cancer cells with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in vitro. p53 wild- and mutant-type gastric and colon cancer cell lines were treated by 5FU alone, TRAIL alone, and a combination of 5FU and TRAIL, and cell viability after each treatment was determined by MTT assay. The p53 wild-type cells were more sensitive to 5FU alone or to TRAIL alone than p53 mutant-type cells. The cell growth inhibitory effects of the combined treatment were supra-additive and more significant in proportion to the increasing concentrations of TRAIL as compared with 5FU alone both in p53 wild- and mutant-type cells. Furthermore, TRAIL could cause a decrease in 5FU IC(50) to within the range of clinically relevant doses, particularly in p53 wild-type cells. This is the first demonstration of the supra-additive antitumor activity of 5FU with TRAIL on gastric cancer cells, giving evidence that TRAIL can reduce the requirement for 5FU that ultimately results in minimizing risks for systemic side effects while increasing the antitumor activity of 5FU, suggesting the clinical applicability of this combination for gastric and colon cancers.

  16. Chrysin, Apigenin and Acacetin Inhibit Tumor Necrosis Factor-Related Apoptosis—Inducing Ligand Receptor-1 (TRAIL-R1 on Activated RAW264.7 Macrophages

    Directory of Open Access Journals (Sweden)

    Monika Warat

    2014-06-01

    Full Text Available Expression level of Tumor Necrosis Factor—related apoptosis—inducing ligand (TRAIL receptors is one of the most important factors of TRAIL-mediated apoptosis in cancer cells. We here report for the first time data concerning TRAIL-R1 and TRAIL-R2 receptor expression on RAW264.7 macrophages. Three substances belonging to flavones: chrysin, apigenin and acacetin which differ from their substituents at the 4' position in the phenyl ring were used in assays because of the variety of biological activities (e.g., anticancer activity of the polyphenol compounds. The expression of TRAIL-R1 and TRAIL-R2 death receptors on non-stimulated and LPS (lipopolysaccharide-stimulated macrophages was determined using flow cytometry. We demonstrate that RAW264.7 macrophages exhibit TRAIL-R1 surface expression and that the tested compounds: chrysin, apigenin and acacetin can inhibit TRAIL-R1 death receptor expression level on macrophages.

  17. Repression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL but not its receptors during oral cancer progression

    Directory of Open Access Journals (Sweden)

    Muller Susan

    2007-06-01

    Full Text Available Abstract Background TRAIL plays an important role in host immunosurveillance against tumor progression, as it induces apoptosis of tumor cells but not normal cells, and thus has great therapeutic potential for cancer treatment. TRAIL binds to two cell-death-inducing (DR4 and DR5 and two decoy (DcR1, and DcR2 receptors. Here, we compare the expression levels of TRAIL and its receptors in normal oral mucosa (NOM, oral premalignancies (OPM, and primary and metastatic oral squamous cell carcinomas (OSCC in order to characterize the changes in their expression patterns during OSCC initiation and progression. Methods DNA microarray, immunoblotting and immunohistochemical analyses were used to examine the expression levels of TRAIL and its receptors in oral epithelial cell lines and in archival tissues of NOM, OPM, primary and metastatic OSCC. Apoptotic rates of tumor cells and tumor-infiltrating lymphocytes (TIL in OSCC specimens were determined by cleaved caspase 3 immunohistochemistry. Results Normal oral epithelia constitutively expressed TRAIL, but expression was progressively lost in OPM and OSCC. Reduction in DcR2 expression levels was noted frequently in OPM and OSCC compared to respective patient-matched uninvolved oral mucosa. OSCC frequently expressed DR4, DR5 and DcR1 but less frequently DcR2. Expression levels of DR4, DR5 and DcR1 receptors were not significantly altered in OPM, primary OSCC and metastatic OSCC compared to patient-matched normal oral mucosa. Expression of proapoptotic TRAIL-receptors DR4 and DR5 in OSCC seemed to depend, at least in part, on whether or not these receptors were expressed in their parental oral epithelia. High DR5 expression in primary OSCC correlated significantly with larger tumor size. There was no significant association between TRAIL-R expression and OSSC histology grade, nodal status or apoptosis rates of tumor cells and TIL. Conclusion Loss of TRAIL expression is an early event during oral

  18. Type I interferons and interferon regulatory factors regulate TNF-related apoptosis-inducing ligand (TRAIL in HIV-1-infected macrophages.

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    Yunlong Huang

    Full Text Available TNF-related apoptosis-inducing ligand (TRAIL is a member of the TNF family that participates in HIV-1 pathogenesis through the depletion of CD4+ T cells. TRAIL is expressed on the cell membrane of peripheral immune cells and can be cleaved into a soluble, secreted form. The regulation of TRAIL in macrophages during HIV-1 infection is not completely understood. In this study, we investigated the mechanism(s of TRAIL expression in HIV-1-infected macrophages, an important cell type in HIV-1 pathogenesis. A human monocyte-derived macrophage (MDM culture system was infected with macrophage-tropic HIV-1(ADA, HIV-1(JR-FL, or HIV-1(BAL strains. TRAIL, predominantly the membrane-bound form, increased following HIV-1 infection. We found that HIV-1 infection also induced interferon regulatory factor (IRF-1, IRF-7 gene expression and signal transducers and activators of transcription 1 (STAT1 activation. Small interfering RNA knockdown of IRF-1 or IRF-7, but not IRF-3, reduced STAT1 activation and TRAIL expression. Furthermore, the upregulation of IRF-1, IRF-7, TRAIL, and the activation of STAT1 by HIV-1 infection was reduced by the treatment of type I interferon (IFN-neutralizing antibodies. In addition, inhibition of STAT1 by fludarabine abolished IRF-1, IRF-7, and TRAIL upregulation. We conclude that IRF-1, IRF-7, type I IFNs, and STAT1 form a signaling feedback loop that is critical in regulating TRAIL expression in HIV-1-infected macrophages.

  19. BRCA-1 promoter hypermethylation and silencing induced by the aromatic hydrocarbon receptor-ligand TCDD are prevented by resveratrol in MCF-7 cells.

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    Papoutsis, Andreas J; Borg, Jamie L; Selmin, Ornella I; Romagnolo, Donato F

    2012-10-01

    Epigenetic mechanisms may contribute to reduced expression of the tumor suppressor gene BRCA-1 in sporadic breast cancers. Through environmental exposure and diet, humans are exposed to xenobiotics and food compounds that bind the aromatic hydrocarbon receptor (AhR). AhR-ligands include the dioxin-like and tumor promoter 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD). The activated AhR regulates transcription through binding to xenobiotic response elements (XREs=GCGTG) and interactions with transcription cofactors. Previously, we reported on the presence of several XREs in the proximal BRCA-1 promoter and that the expression of endogenous AhR was required for silencing of BRCA-1 expression by TCDD. Here, we document that in estrogen receptor-α-positive and BRCA-1 wild-type MCF-7 breast cancer cells, the treatment with TCDD attenuated 17β-estradiol-dependent stimulation of BRCA-1 protein and induced hypermethylation of a CpG island spanning the BRCA-1 transcriptional start site of exon-1a. Additionally, we found that TCDD enhanced the association of the AhR; DNA methyl transferase (DNMT)1, DNMT3a and DNMT3b; methyl binding protein (MBD)2; and trimethylated H3K9 (H3K9me3) with the BRCA-1 promoter. Conversely, the phytoalexin resveratrol, selected as a prototype dietary AhR antagonist, antagonized at physiologically relevant doses (1 μmol/L) the TCDD-induced repression of BRCA-1 protein, BRCA-1 promoter methylation and the recruitment of the AhR, MBD2, H3K9me3 and DNMTs (1, 3a and 3b). Taken together, these observations provide mechanistic evidence for AhR agonists in the establishment of BRCA-1 promoter hypermethylation and the basis for the development of prevention strategies based on AhR antagonists.

  20. The high affinity ALK1-ligand BMP9 induces a hypertrophy-like state in chondrocytes that is antagonized by TGFβ1.

    Science.gov (United States)

    van Caam, A; Blaney Davidson, E; Garcia de Vinuesa, A; van Geffen, E; van den Berg, W; Goumans, M-J; ten Dijke, P; van der Kraan, P

    2015-06-01

    In osteoarthritic cartilage, expression of the receptor ALK1 correlates with markers of deleterious chondrocyte hypertrophy. Recently, bone morphogenetic protein 9 (BMP9) was identified as a high affinity ligand for ALK1. Therefore, we studied if BMP9 signaling results in expression of hypertrophy markers in chondrocytes. Furthermore, because transforming growth factorß1 (TGFβ1) is a well known anti-hypertrophic factor, the interaction between BMP9 and TGFβ1 signaling was also studied. Primary chondrocytes were isolated from bovine cartilage and stimulated with BMP9 and/or TGFβ1 to measure intracellular signaling via pSmads with the use of Western blot. Expression of Smad-responsive genes or hypertrophy-marker genes was measured using qPCR. To confirm observations on TGFβ/Smad3 responsive genes, a Smad3-dependent CAGA12-luc transcriptional reporter assay was performed in the chondrocyte G6 cell line. In primary chondrocytes, BMP9 potently induced phosphorylation of Smad1/5 and Smad2 to a lesser extent. BMP9-induced Smad1/5 phosphorylation was rapidly (2 h) reflected in gene expression, whereas Smad2 phosphorylation was not. Remarkably, BMP9 and TGFβ1 dose-dependently synergized on Smad2 phosphorylation, and showed an additive effect on expression of Smad3-dependent genes like bSerpine1 after 24 h. The activation of the TGFβ/Smad3 signaling cascade was confirmed using the CAGA12-luc transcriptional reporter. BMP9 selectively induced bAlpl and bColX expression, which are considered early markers of cellular hypertrophy, but this was potently antagonized by addition of a low dose of TGFβ1. This study shows that in vitro in chondrocytes, BMP9 potently induces pSmad1/5 and a chondrocyte hypertrophy-like state, which is potently blocked by TGFβ1. This observation underlines the importance of TGFβ1 in maintenance of chondrocyte phenotype. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  1. Ligand-Induced Conformational Changes and Conformational Dynamics in the Solution Structure of the Lactose Repressor Protein

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    Taraban, Marc; Zhan, Hongli; Whitten, Andrew E.; Langley, David B.; Matthews, Kathleen S.; Swint-Kruse, Liskin; Trewhella, Jill

    2008-01-01

    SUMMARY We present here the results of a series of small-angle X-ray scattering studies aimed at understanding the role of conformational changes and structural flexibility in DNA binding and allosteric signaling in a bacterial transcription regulator, Lactose repressor protein (LacI). Experiments were designed to detect possible conformational changes that occur when LacI binds either DNA or the inducer IPTG, or both. Our studies included the native LacI dimer of homodimers and a dimeric variant (R3), enabling us to probe conformational changes within the homodimers and distinguish them from those involving changes in the homodimer-homodimer relationships. The scattering data indicate that removal of operator DNA (oDNA) from R3 results in an unfolding and extension of the hinge-helix that connects the LacI regulatory and DNA-binding domains. In contrast, only very subtle conformational changes occur in the R3 dimer-oDNA complex upon IPTG binding, indicative of small adjustments in the orientations of domains and/or sub-domains within the structure. The binding of IPTG to native (tetrameric) LacI-oDNA complexes also appears to facilitate a modest change in the average homodimer-homodimer disposition. Notably, the crystal structure of the native LacI-oDNA complex differs significantly from the average solution conformation. The solution scattering data are best-fit by an ensemble of structures that includes (1) ~60% of the V-shaped dimer-of-homodimers observed in the crystal structure, and (2) ~40% of molecules with more “open” forms, such as those generated when the homodimers move with respect to each other about the tetramerization domain. In gene regulation, such a flexible LacI would be beneficial for the interaction of its two DNA binding domains, positioned at the tips of the V, with the required two of three LacI operators needed for full repression. PMID:18164724

  2. Bifunctional Zn(II)Ln(III) dinuclear complexes combining field induced SMM behavior and luminescence: enhanced NIR lanthanide emission by 9-anthracene carboxylate bridging ligands.

    Science.gov (United States)

    Palacios, María A; Titos-Padilla, Silvia; Ruiz, José; Herrera, Juan Manuel; Pope, Simon J A; Brechin, Euan K; Colacio, Enrique

    2014-02-03

    There were new dinuclear Zn(II)-Ln(III) complexes of general formulas [Zn(μ-L)(μ-OAc)Ln(NO3)2] (Ln(III) = Tb (1), Dy (2), Er (3), and Yb (4)), [Zn(μ-L)(μ-NO3)Er(NO3)2] (5), [Zn(H2O)(μ-L)Nd(NO3)3]·2CH3OH (6), [Zn(μ-L)(μ-9-An)Ln(NO3)2]·2CH3CN (Ln(III) = Tb (7), Dy (8), Er (9), Yb(10)), [Zn(μ-L)(μ-9-An)Yb(9-An)(NO3)3]·3CH3CN (11), [Zn(μ-L)(μ-9-An)Nd(9-An)(NO3)3]·2CH3CN·3H2O (12), and [Zn(μ-L)(μ-9-An)Nd(CH3OH)2(NO3)]ClO4·2CH3OH (13) prepared from the reaction of the compartmental ligand N,N',N″-trimethyl-N,N″-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine (H2L), with ZnX2·nH2O (X = NO3(-) or OAc(-)) salts, Ln(NO3)3·nH2O, and, in some instances, 9-anthracenecarboxylate anion (9-An). In all these complexes, the Zn(II) ions invariably occupy the internal N3O2 site whereas the Ln(III) ions show preference for the O4 external site, giving rise to a Zn(μ-diphenoxo)Ln bridging fragment. Depending on the Zn(II) salt and solvent used in the reaction, a third bridge can connect the Zn(II) and Ln(III) metal ions, giving rise to triple-bridged diphenoxoacetate in complexes 1-4, diphenoxonitrate in complex 5, and diphenoxo(9-anthracenecarboxylate) in complexes 8-13. Dy(III) and Er(III) complexes 2, 8 and 3, 5, respectively, exhibit field induced single molecule magnet (SMM) behavior, with Ueff values ranging from 11.7 (3) to 41(2) K. Additionally, the solid-state photophysical properties of these complexes are presented showing that ligand L(2-) is able to sensitize Tb(III)- and Dy(III)-based luminescence in the visible region through an energy transfer process (antenna effect). The efficiency of this process is much lower when NIR emitters such as Er(III), Nd(III), and Yb(III) are considered. When the luminophore 9-anthracene carboxylate is incorporated into these complexes, the NIR luminescence is enhanced which proves the efficiency of this bridging ligand to act as antenna group. Complexes 2, 3, 5, and 8 can be considered as dual materials

  3. Solid-state ligand-driven light-induced spin change at ambient temperatures in bis(dipyrazolylstyrylpyridine)iron(II) complexes.

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    Takahashi, Kazuhiro; Hasegawa, Yuta; Sakamoto, Ryota; Nishikawa, Michihiro; Kume, Shoko; Nishibori, Eiji; Nishihara, Hiroshi

    2012-05-07

    We previously reported that an Fe(II) complex ligated by two (Z)-2,6-di(1H-pyrazol-1-yl)-4-styrylpyridine ligands (Z-H) presented a solid state ligand-driven light-induced spin change (LD-LISC) upon one-way Z-to-E photoisomerization, although modulation of the magnetism was trivial at ambient temperatures (Chem. Commun.2011, 47, 6846). Here, we report the synthesis of new derivatives of Z-H, Z-CN and Z-NO(2), in which electron-withdrawing cyano and nitro substituents are introduced at the 4-position of the styryl group to attain a more profound photomagnetism at ambient temperatures. Z-CN and Z-NO(2) undergo quantitative one-way Z-to-E photochromism upon excitation of the charge transfer band both in acetonitrile and in the solid state, similar to the behavior observed for Z-H. In solution, these substituents stabilized the low-spin (LS) states of Z-CN and Z-NO(2), and the behavior was quantitatively analyzed according to the Evans equation. The photomagnetic properties in the solid state, on the other hand, cannot be explained in terms of the substituent effect alone. Z-CN displayed photomagnetic properties almost identical to those of Z-H. Z-CN preferred the high-spin (HS) state at all temperatures tested, whereas photoirradiated Z-CN yielded a lower χ(M)T at ambient temperatures. The behavior of Z-NO(2) was counterintuitive, and the material displayed surprising photomagnetic properties in the solid state. Z-NO(2) occupied the LS state at low temperatures and underwent thermal spin crossover (SCO) with a T(1/2) of about 270 K. The photoirradiated Z-NO(2) displayed a higher value of χ(M)T and the modulation of χ(M)T exceeded that of Z-H or Z-CN. Z-NO(2)·acetone, in which acetone molecules were incorporated into the crystal lattice, further stabilized the LS state (T(1/2) > 300 K), thereby promoting large modulations of the χ(M)T values (87% at 273 K and 64% at 300 K) upon Z-to-E photoisomerization. Single crystal X-ray structure analysis revealed that

  4. Association Study of a Proliferation-inducing Ligand, Spermatogenesis Associated 8, Platelet-derived Growth Factor Receptor-alpha, and POLB Polymorphisms with Systemic Lupus Erythematosus in Chinese Han Population

    OpenAIRE

    Ping Li; Yuan Li; Ai-Hong Zhou; Si Chen; Jing Li; Xiao-Ting Wen; Zi-Yan Wu; Liu-Bing Li; Feng-Chun Zhang; Yong-Zhe Li

    2016-01-01

    Background: Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease with complex genetic inheritance. This study was conducted to examine whether the association of a proliferation-inducing ligand (APRIL), spermatogenesis associated 8 (SPATA8), platelet-derived growth factor receptor-alpha (PDGFRA), and DNA polymerase beta (POLB) with SLE can be replicated in a Chinese Han population. Methods: Chinese SLE patients (n = 1247) and ethnically and geographically matched healthy cont...

  5. Target and resistance-related proteins of recombinant mutant human tumor necrosis factor-related apoptosis-inducing ligand on myeloma cell lines.

    Science.gov (United States)

    Jian, Yuan; Chen, Yuling; Geng, Chuanying; Liu, Nian; Yang, Guangzhong; Liu, Jinwei; Li, Xin; Deng, Haiteng; Chen, Wenming

    2016-06-01

    Recombinant mutant human tumor necrosis factor-related apoptosis-inducing ligand (rmhTRAIL) has become a potential therapeutic drug for multiple myeloma (MM). However, the exact targets and resistance mechanisms of rmhTRAIL on MM cells remain to be elucidated. The present study aimed to investigate the target and resistance-related proteins of rmhTRAIL on myeloma cell lines. A TRAIL-sensitive myeloma cell line, RPMI 8226, and a TRAIL-resistance one, U266, were chosen and the differentially expressed proteins between the two cell lines were analyzed prior and subsequent to rmhTRAIL administration by a liquid chromatography-tandem mass spectrometry method. The results showed that following TRAIL treatment, 6 apoptosis-related proteins, calpain small subunit 1 (CPNS1), peflin (PEF1), B-cell receptor-associated protein 31 (BAP31), apoptosis-associated speck-like protein containing CARD (ASC), BAG family molecular chaperone regulator 2 (BAG2) and chromobox protein homolog 3 (CBX3), were upregulated in RPMI 8226 cells while no change was identified in the U266 cells. Furthermore, small ubiquitin-related modifier 1 and several other ubiquitin proteasome pathway (UPP)-related proteins expressed higher levels in TRAIL-resistant cells U266 compared to the RPMI-8226 cells prior and subsequent to rmhTRAIL treatment. These results suggested that CPNS1, PEF1, BAP31, ASC, BAG2 and CBX3 were possibly target proteins of rmhTRAIL on RPMI 8226 cells, while UPP may have a vital role in mediating TRAIL-resistance in U266 cells.

  6. Suppression of collagen-induced arthritis by oral administration of transgenic rice seeds expressing altered peptide ligands of type II collagen.

    Science.gov (United States)

    Iizuka, Mana; Wakasa, Yuhya; Tsuboi, Hiroto; Asashima, Hiromitsu; Hirota, Tomoya; Kondo, Yuya; Matsumoto, Isao; Takaiwa, Fumio; Sumida, Takayuki

    2014-10-01

    Rheumatoid arthritis (RA) is an autoimmune disease associated with the recognition of self proteins secluded in arthritic joints. We previously reported that altered peptide ligands (APLs) of type II collagen (CII256-271) suppress the development of collagen-induced arthritis (CIA). In this study, we generated transgenic rice expressing CII256-271 and APL6 contained in fusion proteins with the rice storage protein glutelin in the seed endosperm. These transgene products successfully and stably accumulated at high levels (7-24 mg/g seeds) in protein storage vacuoles (PB-II) of mature seeds. We examined the efficacy of these transgenic rice seeds by performing oral administration of the seeds to CIA model mice that had been immunized with CII. Treatment with APL6 transgenic rice for 14 days significantly inhibited the development of arthritis (based on clinical score) and delayed disease onset during the early phase of arthritis. These effects were mediated by the induction of IL-10 from CD4(+ ) CD25(-) T cells against CII antigen in splenocytes and inguinal lymph nodes (iLNs), and treatment of APL had no effect on the production of IFN-γ, IL-17, IL-2 or Foxp3(+) Treg cells. These findings suggest that abnormal immune suppressive mechanisms are involved in the therapeutic effect of rice-based oral vaccine expressing high levels of APLs of type II collagen on the autoimmune disease CIA, suggesting that the seed-based mucosal vaccine against CIA functions via a unique mechanism.

  7. Role of interferon gamma and tumor necrosis factor-related apoptosis-inducing ligand receptor 1 single nucleotide polymorphism in natural clearance and treatment response of HCV infection.

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    Azam, Sikandar; Manzoor, Sobia; Imran, Muhammad; Ashraf, Javed; Ashraf, Sarah; Resham, Saleha; Ghani, Eijaz

    2015-05-01

    Hepatitis C virus (HCV) pathogenesis and treatment outcomes are multifactorial phenomena involving both viral and host factors. This study was designed to determine the role of tumor necrosis factor-related apoptosis-inducing ligand receptor 1(TRAIL-R1) and interferon gamma (IFN-γ) genetic mutations in susceptibility and response to interferon-based therapy of hepatitis C virus (HCV) infection. The detection of TRAIL-R1 rs4242392 and IFN-γ rs2069707 single nucleotide polymorphisms was completed in 118 chronic HCV patients and 96 healthy controls by allele-specific polymerase chain reaction and restriction fragment length polymorphisms polymerase chain reaction. Patients were further categorized into sustained virological responder (SVR) and nonresponder (NR) groups on the basis of their response to interferon-based therapy for HCV infection. Real-time PCR was used for HCV quantification. HCV genotyping was performed by Ohno's method. The results demonstrated that the distribution of the TRAIL-R1 rs4242392TT genotype was significantly higher in the SVR group (78%) compared to the NR group (36%). It showed that chronic HCV patients possessing the TRAIL-R1 rs4242392TT genotype are better responders to interferon-based therapy (p0.05). The distribution of IFN-γ rs2069707 was the opposite to TRAIL-R1 rs4242392 prevalence, that is, there was high distribution of the IFN-γ rs2069707GG genotype in patients and healthy controls (p0.05). In conclusion, genetic variation of TRAIL-R1 rs4242392 is linked with response to interferon-based therapy for HCV infection, and genetic variation IFN-γ rs2069707 is associated with natural clearance of HCV infection.

  8. A Comparison of the Anorectic Effect and Safety of the Alpha2-Adrenoceptor Ligands Guanfacine and Yohimbine in Rats with Diet-Induced Obesity.

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    Magdalena Dudek

    Full Text Available The search for drugs with anorectic activity, acting within the adrenergic system has attracted the interest of researchers. Partial α2-adrenoceptor agonists might offer the potential for effective and safe treatment of obesity. We compared the effectiveness and safety of α2-adrenoceptor ligands in reducing body mass. We also analyzed if antagonist and partial agonists of α2-adrenoceptor--yohimbine and guanfacine--act similarly, and determined which course of action is connected with anorectic activity. We tested intrinsic activity and effect on the lipolysis of these compounds in cell cultures, evaluated their effect on meal size, body weight in Wistar rats with high-fat diet-induced obesity, and determined their effect on blood pressure, heart rate, lipid profile, spontaneous locomotor activity, core temperature and glucose, as well as glycerol and cortisol levels. Both guanfacine and yohimbine showed anorectic activity. Guanfacine was much more effective than yohimbine. Both significantly reduced the amount of intraperitoneal adipose tissue and had a beneficial effect on lipid profiles. Decreased response of α2A-adrenoceptors and partial stimulation of α2B-receptors seem to be responsible for the anorectic action of guanfacine. The stimulation of α1-adrenoceptors by guanfacine is responsible for cardiovascular side effects but may also be linked with improved anorexic effect. α1-adrenoceptor blockade is connected with the side effects of yohimbine, but it is also associated with the improvement of lipid profiles. Guanfacine has been approved by the Food and Drug Administration (FDA to treat hypertension and conduct disorder, but as it reduces body weight, it is worth examining its effectiveness and safety in models of obesity.

  9. Pan-HER-An antibody mixture targeting EGFR, HER2 and HER3 abrogates preformed and ligand-induced EGFR homo- and heterodimers.

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    Ellebaek, Sofie; Brix, Susanne; Grandal, Michael; Lantto, Johan; Horak, Ivan D; Kragh, Michael; Poulsen, Thomas Tuxen

    2016-11-01

    The human epidermal growth factor receptor (HER)-family is involved in development of many epithelial cancers. Therefore, HER-family members constitute important targets for anti-cancer therapeutics such as monoclonal antibodies (mAbs). A limitation to the success of single HER-targeting mAbs is development of acquired resistance through mechanisms such as alterted receptor dimerization patterns and dependencies. Pan-HER is a mixture of six mAbs simultaneously targeting epidermal growth factor receptor (EGFR), HER2 and HER3 with two mAbs against each receptor. Pan-HER has previously demonstrated broader efficacy than targeting single or dual receptor combinations also in resistant settings. In light of this broad efficacy, we decided to investigate the effect of Pan-HER compared with single HER-targeting with single and dual mAbs on HER-family cross-talk and dimerization focusing on EGFR. The effect of Pan-HER on cell proliferation and HER-family receptor degradation was superior to treatment with single mAbs targeting either single receptor, and similar to targeting a single receptor with two non-overlapping antibodies. Furthermore, changes in EGFR-dimerization patterns after treatment with Pan-HER were investigated by in situ proximity ligation assay and co-immunoprecipitation, demonstrating that Pan-HER and the EGFR-targeting mAb mixture efficiently down-regulate basal EGFR homo- and heterodimerization in two tested cell lines, whereas single mAbs had limited effects. Pan-HER and the EGFR-targeting mAb mixture also blocked EGF-binding and thereby ligand-induced changes in EGFR-dimerization levels. These results suggest that Pan-HER reduces the cellular capability to switch HER-dependency and dimerization pattern in response to treatment and thus hold promise for future clinical development of Pan-HER in resistant settings.

  10. TLR9 ligand (CpG oligodeoxynucleotide induces CLL B-cells to differentiate into CD20+ antibody-secreting cells

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    Hussein eGhamlouch

    2014-06-01

    Full Text Available B-cell chronic lymphocytic leukemia (CLL is the most frequent adult leukemia in the Western world. It is a heterogeneous disease characterized by clonal proliferation and the accumulation of CD5+ mature B lymphocytes. However, the normal counterpart from which the latter cells arise has not yet been identified. CD27 expression and gene expression profiling data suggest that CLL cells are related to memory B-cells. In vitro, memory B-cells differentiate into plasma cells when stimulated with CpG oligodeoxynucleotide (CpG. The objective of the present study was therefore to investigate the ability of CpG, in the context of CD40 ligation, to induce the differentiation of CLL B-cells into antibody-secreting cells (ASCs. CD20+CD38− CLL B-cells were stimulated with a combination of CpG, CD40 ligand and cytokines (CpG/CD40L/c in a two-step, seven-day culture system. We found that the CpG/CD40L/c culture system prompted CLL B-cells to differentiate into CD19+CD20+CD27+CD38- ASCs. These cells secreted large amounts of IgM and had the same shape as plasma cells. However, only IgMs secreted by ASCs that had differentiated from unmutated CLL B-cells were poly/autoreactive. Class-switch recombination to IgG and IgA was detected in cells expressing the activation-induced cytidine deaminase gene (AICDA. Although these ASCs expressed high levels of the transcription factors PRDM1 (BLIMP1, IRF4 and XBP1s, they did not downregulate expression of PAX5. Our results suggest that CLL B-cells can differentiate into ASCs, undergo class-switch recombination and produce poly/autoreactive antibodies. Furthermore, our findings may be relevant for (i identifying the normal counterpart of CLL B-cells and (ii developing novel treatment strategies in CLL.

  11. A novel role of Rho-kinase in the regulation of ligand-induced phosphorylated EGFR endocytosis via the early/late endocytic pathway in human fibrosarcoma cells.

    Science.gov (United States)

    Nishimura, Yukio; Bereczky, Biborka; Yoshioka, Kiyoko; Taniguchi, Shun'ichiro; Itoh, Kazuyuki

    2011-10-01

    The small GTPase RhoA and its downstream effectors, the Rho-associated kinase (Rho-kinase) family, are known to regulate cell morphology, motility, and tumor progression via the regulation of actin cytoskeleton rearrangement. In the present study, we evaluated the role of Rho-kinase in the intracellular endocytic trafficking of ligand-induced phosphorylated epidermal growth factor receptor (pEGFR). We investigated the time course of the internalization fate of EGF-induced pEGFR via the early/late endocytic pathway in human fibrosarcoma cell line HT1080 cells using Y-27632, a selective Rho-kinase inhibitor. We found, using confocal immunofluorescence microscopy and Western blot analysis, a large accumulation of pEGFR in the nuclei of HT1080 cells. In contrast, we observed decreased amounts of the pEGFR-positive staining in the nuclei along with an accumulation of cytosolic pEGFR staining when the cells were incubated for 15-30 min in the presence of Y-27632, implying that an aberrant endocytic trafficking mechanism of pEGFR occurs in HT1080 cells whereby pEGFR might be selectively translocated into the nucleus. Moreover, we demonstrated that after 15-min of stimulation with Texas Red-EGF, increasing numbers of pEGFR-positive staining that had colocalized with Texas Red-EGF-positive punctate staining were seen in the cytoplasm of HT1080 cells but after 30-min of stimulation, most of this staining had disappeared from the cytoplasm and a large accumulation of pEGFR-positive staining appeared in the nucleus. Thus, nuclear accumulation of pEGFR appears to occur in an EGF-dependent manner. In contrast, such nuclear pEGFR-positive staining was not seen in the Y-27632-treated cells. Furthermore, silencing of RhoA or Rho-kinases I/II by sequence specific siRNAs considerably inhibited the EGF-dependent nuclear accumulation of pEGFR. Collectively, these results provide the first evidence that Rho-kinase signaling pathway plays a suppressive role in the intracellular vesicle

  12. Prevention and recovery of (mu(3)-diethylentriamino)-chloro-palladium(II)-chloride induced inhibition of Na/K-ATPase by SH containing ligands--L-cysteine and glutathione.

    Science.gov (United States)

    Krinulović, Katarina; Bugarcić, Zivadin; Vrvić, Miroslav; Krstić, Danijela; Vasić, Vesna

    2006-12-01

    The effect of (mu(3)-diethylentriamino)-chloro-palladium(II)-chloride ([PdCl(dien)]Cl) on the activity of Na/K-ATPase from porcine cerebral cortex was studied in vitro, in the absence and presence of -SH containing ligands L-cysteine and glutathione (GSH). The aim of the study was to elucidate the mechanism of [PdCl(dien)](+) induced inhibition of the enzyme activity and to examine the ability of thiols to prevent and recover the inhibition. The coordinative interaction between [PdCl(dien)](+) and enzyme was verified by UV and (1)H NMR spectra. The semblance in the changes in absorption spectra of [PdCl(dien)](+) in the presence of Na/K-ATPase and thiols (L-cysteine and GSH) suggested that the complex ion interacts with enzymatic sulfhydryl groups. [PdCl(dien)](+) inhibited the enzyme activity in a dose-dependent manner. The Hill analysis of the inhibition curve yielded the half-maximum inhibitory activity value, IC(50)=1.21 x 10(-4)M, and Hill coefficient, n=0.7, suggesting the negative cooperation for binding of [PdCl(dien)](+) to the enzyme. Dependence of the initial reaction rate on the concentration of MgATP(2-) exhibited typical Michelis-Menten kinetics in the absence and presence of the inhibitor. Kinetic analysis showed that [PdCl(dien)](+) inhibited Na/K-ATPase by reducing the maximum reaction rate (V(max)), rather than changing the affinity to the substrate (K(m)). Kinetic parameters derived using Lineweaver-Burk transformation of experimental data indicated the non-competitive nature of Na/K-ATPase inhibition. The inhibitory constant, K(i)=1.05 x 10(-4)M, was determined from secondary replot of Lineweaver-Burk graph, and correlated with stability constants of [Pd(dien)(thiol)] complexes. 1 x 10(-3)M L-cysteine or GSH prevented the enzyme inhibition induced by Pd(II) complex cation when present below 1 x 10(-4)M. The both thiols completely reversed the inhibited activity in the concentration dependent manner, due to the complex formation with [PdCl(dien)](+).

  13. Killing effect of TNF-related apoptosis inducing ligand regulated by tetracycline on gastric cancer cell line NCI-N87

    Institute of Scientific and Technical Information of China (English)

    Xiao-Chao Wei; Xin-Juan Wang; Kai-Chen; Lei Zhang; Yu Liang; Xin-Li Lin

    2001-01-01

    AIM To clone the cDNA fragment of human TRAIL (TNFrelated apoptosis inducing ligand) into a tetracyclineregulated gene expression system, the RevTet-On system, transduce expression vectors into a gastric carcinoma cell line-NCl-N87 and examine the effects of controlled expression of TRAIL in vitro on the gastric carcinoma cells. METHODS The full-length cDNA of TRAIL was inserted into a vector under the control of the tetracyclineresponsive element (TRE) to obtain the plasmid pRevTRETRAIL, which was transfected into a packaging cell line PT67. In addition, vector pRev-Tet- On and pRevTRE were also transfected into PT67 separately. After hygromycin and G418 selection, the viral titer was determined. The medium containing retroviral vectors was collected and used to transduce a gastric carcinoma cell line NCI-N87.The resulting cell line NCI-N87-Tet-On-TRE-TRAIL and a control cell line, NCI-N87-Tet-On-TRE, were established.TRAIL expression in the cell line was induced by incubating cells with doxycycline (Dox), which is a tetracycline analogue. The killing effect on gastric carcinoma cells was analyzed after induction. RESULTS The recombinant plasmid pRev-TRE-TRAIL was constructed. After hygromycin or G418 selection, the producer cell lines PT67-TRE, PT67-TRE-TRAIL and PT67TetOn were obtained, with titers of about 108CFU@ L-1 By transducing NCI-N87 cells with retroviral vectors from these cell lines, stable cell lines NCI-N87-Tet-On-TRETRAIL (NN3T) and control cell line NCI-N87-Tet-On-TRE (NN2T) were established. The growth curves of the selected cell lines were the same with the wild type NCIN87. When Dox was added, cell death was obvious in the test groups (29% -77%), whereas no difference was observed in control and wild type cell lines. With the addition of a medium from the test group, human leukemia cell line Jurkat was activated till death (83%), indicating the secretion of active TRAIL proteins from the test cells to the medium. CONCLUSION With the use of the

  14. Protection against murine leukemia virus-induced spongiform myeloencephalopathy in mice overexpressing Bcl-2 but not in mice deficient for interleukin-6, inducible nitric oxide synthetase, ICE, Fas, Fas ligand, or TNF-R1 genes.

    Science.gov (United States)

    Jolicoeur, Paul; Hu, Chunyan; Mak, Tak W; Martinou, Jean-Claude; Kay, Denis G

    2003-12-01

    Some murine leukemia viruses (MuLVs), among them Cas-Br-E and ts-1 MuLVs, are neurovirulent, inducing spongiform myeloencephalopathy and hind limb paralysis in susceptible mice. It has been shown that the env gene of these viruses harbors the determinant of neurovirulence. It appears that neuronal loss occurs by an indirect mechanism, since the target motor neurons have not been found to be infected. However, the pathogenesis of the disease remains unclear. Several lymphokines, cytokines, and other cellular effectors have been found to be aberrantly expressed in the brains of infected mice, but whether these are required for the development of the neurodegenerative lesions is not known. In an effort to identify the specific effectors which are indeed required for the initiation and/or development of spongiform myeloencephalopathy, we inoculated gene-deficient (knockout [KO]) mice with ts-1 MuLV. We show here that interleukin-6 (IL-6), inducible nitric oxide synthetase (iNOS), ICE, Fas, Fas ligand (FasL), and TNF-R1 KO mice still develop signs of disease. However, transgenic mice overexpressing Bcl-2 in neurons (NSE/Bcl-2) were largely protected from hind limb paralysis and had less-severe spongiform lesions. These results indicate that motor neuron death occurs in this disease at least in part by a Bcl-2-inhibitable pathway not requiring the ICE, iNOS, Fas/FasL, TNF-R1, and IL-6 gene products.

  15. A proliferation-inducing ligand sustains the proliferation of human naïve (CD27⁻) B cells and mediates their differentiation into long-lived plasma cells in vitro via transmembrane activator and calcium modulator and cyclophilin ligand interactor and B-cell mature antigen.

    Science.gov (United States)

    Matsuda, Yoshiko; Haneda, Masataka; Kadomatsu, Kenji; Kobayashi, Takaaki

    2015-06-01

    Long-lived plasma cells (PCs) contribute to humoral immunity through an undefined mechanism. Memory B cells, but not human naïve B cells, can be induced to differentiate into long-lived PCs in vitro. Because evidence links a proliferation-inducing ligand (APRIL), a tumor necrosis factor family member, to the ability of bone marrow to mediate long-term PC survival, we reasoned that APRIL influences the proliferation and differentiation of naïve B cells. We describe here the development of a simple cell culture system that allowed us to show that APRIL sustained the proliferation of naïve human B cells and induced them to differentiate into long-lived PCs. Blocking the transmembrane activator and calcium modulator and cyclophilin ligand interactor or B-cell mature antigen shows they were required for the differentiation of naïve B cells into long-lived PCs in vitro. Our in vitro culture system will reveal new insights into the biology of long-lived PCs.

  16. Effects of the anti-receptor activator of nuclear factor kappa B ligand denusomab on beta thalassemia major-induced osteoporosis

    Directory of Open Access Journals (Sweden)

    Mohamed A Yassin

    2014-01-01

    Full Text Available Introduction: Osteoporosis represents the second most common cause of endocrinopathy in patients with beta thalassemia major (BTM. Some drugs proved effective to reduce vertebral and non-vertebral fracture risk. Denosumab is a fully human monoclonal antibody to the receptor activator of nuclear factor kappa B ligand (RANKL, a member of the tumor necrosis factor receptor superfamily essential for osteoclastogenesis. The efficacy and safety of denosumab in BTM-induced osteoporosis has not been tested. Objective: To evaluate the efficacy and safety of anti-RANKL on the biochemical and radiological parameters of bone mineralization in patients with BTM-induced osteoporosis. Design: The study population was selected using the random sampling method from the patient′s database of our thalassemia clinic. Transfusion-dependent BTM patients above 18 years with no history of treatment with bisphosphonates were randomly selected. Bone mineral density (BMD of the lumbar spine (LS and right femoral neck (FN were measured by dual energy X-ray absorption (DEXA scan using a calibrated method. Independent factors likely to be associated with low bone mass were determined and included in the analysis to ascertain possible associations. Patients and Methods: We studied 30 patients with BTM-induced osteoporosis as per World Health Organization criteria (T Score of less than − 1.0 being defined as osteopenic and a T Score of less than − 2.5 being referred as osteoporotic. 19 males and 11 females aged between 18 and 32 years, with full pubertal development (Tanner′s stage 5 at the time of the study. Their mean serum ferritin concentration was 3557 ng ± 1488 ng/ml. Every patient underwent DEXA scan as a baseline and after 12 months of denosumab therapy. Biochemical evaluation including serum concentrations of creatinine, Na, K, calcium, phosphorus, parathormone, bone specific alkaline phosphatase and type 1 collagen carboxy telopetide (ICCT using enzyme

  17. Ligand-induced movements of inner transmembrane helices of Glut1 revealed by chemical cross-linking of di-cysteine mutants.

    Directory of Open Access Journals (Sweden)

    Mike Mueckler

    Full Text Available The relative orientation and proximity of the pseudo-symmetrical inner transmembrane helical pairs 5/8 and 2/11 of Glut1 were analyzed by chemical cross-linking of di-cysteine mutants. Thirteen functional di-cysteine mutants were created from a C-less Glut1 reporter construct containing cysteine substitutions in helices 5 and 8 or helices 2 and 11. The mutants were expressed in Xenopus oocytes and the sensitivity of each mutant to intramolecular cross-linking by two homobifunctional thiol-specific reagents was ascertained by protease cleavage followed by immunoblot analysis. Five of 9 mutants with cysteine residues predicted to lie in close proximity to each other were susceptible to cross-linking by one or both reagents. None of 4 mutants with cysteine substitutions predicted to lie on opposite faces of their respective helices was susceptible to cross-linking. Additionally, the cross-linking of a di-cysteine pair (A70C/M420C, helices 2/11 predicted to lie near the exoplasmic face of the membrane was stimulated by ethylidene glucose, a non-transported glucose analog that preferentially binds to the exofacial substrate-binding site, suggesting that the binding of this ligand stimulates the closure of helices at the exoplasmic face of the membrane. In contrast, the cross-linking of a second di-cysteine pair (T158C/L325, helices 5/8, predicted to lie near the cytoplasmic face of the membrane, was stimulated by cytochalasin B, a glucose transport inhibitor that competitively inhibits substrate efflux, suggesting that this compound recruits the transporter to a conformational state in which closure of inner helices occurs at the cytoplasmic face of the membrane. This observation provides a structural explanation for the competitive inhibition of substrate efflux by cytochalasin B. These data indicate that the binding of competitive inhibitors of glucose efflux or influx induce occluded states in the transporter in which substrate is excluded from

  18. Inhibition of MicroRNA-149-5p Induces Apoptosis of Acute Myeloid Leukemia Cell Line THP-1 by Targeting Fas Ligand (FASLG)

    Science.gov (United States)

    Tian, Peijun; Yan, Li

    2016-01-01

    Background This study was aimed to reveal the role of miR-149-5p in acute myeloid leukemia (AML) cells apoptosis and the possible mechanism involved. Material/Methods The expression of miR-149-5p in leukemia cell lines, as well as the blood and bone marrow (BM) samples from leukemia patients, were monitored by reverse-transcription polymerase chain reaction (RT-PCR). AML cell line THP-1 was transfected with miR-149-5p mimic or inhibitor, and then cell apoptosis was determined using the APO Percentage assay kit. The target of miR-149-5p was predicted by using the microRNA.org database, and verified by RT-PCR, Western blot, and Dual-Luciferase reporter assays. Further, small interfering RNA (siRNA) against the target gene was co-transfected with miR-149-5p inhibitor, and then the cell apoptosis and the expression of apoptosis-related proteins were assessed. Results MiR-149-5p was significantly up-regulated in leukemia cell lines and samples from leukemia patients (P<0.01 or P<0.001), especially in THP-1 cells and samples from AML patients. Cell apoptosis was significantly decreased by miR-149-5p overexpression (P<0.01) and increased by miR-149-5p suppression (P<0.05). Fas Ligand (FASLG) was a direct target of miR-149-5p, and was negatively regulated by miR-149-5p. More importantly, the inductive effects of miR-149-5p suppression on cell apoptosis were abrogated by si-FASLG (P<0.01). Furthermore, the up-regulative effects of miR-149-5p suppression on the phosphorylated form of Fas-associated via death domain (p-FADD), caspase-8, caspase-2, caspase-3, and the cleaved forms of these caspases were abrogated by si-FASLG. Conclusions Inhibition of miR-149-5p can induce apoptosis in THP-1 cells. These inductive effects might be via targeting FASLG and activating FADD and caspases. PMID:28013316

  19. Collision-induced dissociation of noncovalent complexes between vancomycin antibiotics and peptide ligand stereoisomers: evidence for molecular recognition in the gas phase

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J. D.; Delforge, D; Remacle, J

    1999-01-01

    In solution, the antibiotics of the vancomycin group bind stereospecifically to peptides with the C-terminal sequence: -L-Lys-D-Ala-D-Ala, Substitution by a L-Ala at either of the two C-terminal residues causes a dramatic decrease in the binding affinity to the antibiotics. This solution behavior...... of an antibiotic, a -L-Ala peptide, a -D-Ala stereoisomer, one ligand isotopically labelled. Upon CID of the negatively charged mixed cluster ions a stereoselective loss of the assumed "nonspecifically" bound -L-Ala ligand was observed. (Int J Mass Spectrom 188 (1999) 63-85) (C) 1999 Elsevier Science B.V....

  20. In acute myeloid leukemia, B7-H1 (PD-L1) protection of blasts from cytotoxic T cells is induced by TLR ligands and interferon-gamma and can be reversed using MEK inhibitors.

    Science.gov (United States)

    Berthon, Céline; Driss, Virginie; Liu, Jizhong; Kuranda, Klaudia; Leleu, Xavier; Jouy, Nathalie; Hetuin, Dominique; Quesnel, Bruno

    2010-12-01

    B7-H1 (PD-L1) is a B7-related protein that inhibits T-cell responses. B7-H1 participates in the immunoescape of cancer cells and is also involved in the long-term persistence of leukemic cells in a mouse model of leukemia. B7-H1 can be constitutively expressed by cancer cells, but is also induced by various stimuli. Therefore, we examined the constitutive and inducible expression of B7-H1 and the consequences of this expression in human acute myeloid leukemia (AML). We analyzed B7-H1 expression in a cohort of 79 patients with AML. In addition, we studied blast cells after incubation with interferon-gamma or toll-like receptors (TLR) ligands. Finally, we evaluated functionality of cytotoxic T-cell activity against blast cells. Expression of B7-H1 upon diagnosis was high in 18% of patients. Expression of TLR2, 4 and 9 was detected in one-third of AML samples. Expression of TLR2 and TLR4 ligands or IFN-γ induced by B7-H1 was found to protect AML cells from CTL-mediated lysis. Spontaneous B7-H1 expression was also found to be enhanced upon relapse in some patients. MEK inhibitors, including UO126 and AZD6244, reduced B7-H1 expression and restored CTL-mediated lysis of blast cells. In AML, B7-H1 expression by blasts represents a possible immune escape mechanism. The inducibility of B7-H1 expression by IFN-γ or TLR ligands suggests that various stimuli, either produced during the immune response against leukemia cells or released by infectious microorganisms, could protect leukemic cells from T cells. The efficacy of MEK inhibitors against B7-H1-mediated inhibition of CTLs suggests a possible cancer immunotherapy strategy using targeted drugs.

  1. Light-Induced Copper(II) Coordination by a Bicyclic Tetraaza Chelator through a Ligand-to-Metal Charge-Transfer Reaction

    DEFF Research Database (Denmark)

    Holm-Jørgensen, Jacob Rørdam; Jensen, Mikael; Bjerrum, Morten J.

    2011-01-01

    To enable utilization of the broad potential of copper isotopes in nuclear medicine, rapid and robust chelation of the copper is required. Bowl adamanzanes (bicyclic tetraaza ligands) can form kinetically stable copper complexes, but they are usually formed at low rates unless high pH values...

  2. Alcohol-Induced C-N Bond Cleavage of Cyclometalated N-Heterocyclic Carbene Ligands with a Methylene-Linked Pendant Imidazolium Ring.

    Science.gov (United States)

    Zhong, Wei; Fei, Zhaofu; Scopelliti, Rosario; Dyson, Paul J

    2016-08-16

    Reaction of the pentamethylcyclopentadienyl rhodium iodide dimer [Cp*RhI2 ]2 with 1,1'-diphenyl-3,3'-methylenediimidazolium diiodide in non-alcohol solvents, in the presence of base, led to the formation of bis-carbene complex [Cp*Rh(bis-NHC)I]I (bis-NHC=1,1'-diphenyl-4,4'-methylenediimidazoline-5,5'-diylidene). In contrast, when employing alcohols as the solvent in the same reaction, cleavage of a methylene C-N bond is observed, affording ether-functionalized (cyclometalated) carbene ligands coordinated to the metal center and the concomitant formation of complexes with a coordinated imidazole ligand. Studies employing other 1,1'-diimidazolium salts indicate that the cyclometalation step is a prerequisite for the activation/scission of the C-N bond and, based on additional experimental data, a SN 2 mechanism for the reaction is tentatively proposed.

  3. Anion-induced Ag(I) self-assemblies with electron deficient aromatic ligands: anion-π-system interactions as a driving force for templated coordination networks.

    Science.gov (United States)

    Safin, Damir A; Pialat, Amélie; Leitch, Alicea A; Tumanov, Nikolay A; Korobkov, Ilia; Filinchuk, Yaroslav; Brusso, Jaclyn L; Murugesu, Muralee

    2015-06-11

    Three novel 1D, 2D and 3D coordination polymers were successfully isolated using nitrogen based 3,6-bis(2'-pyrimidyl)-1,2,4,5-tetrazine (BPymTz) and 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine (TPymT) ligands with Ag(I) ions. The formation of these supramolecular assemblies was templated through anion-π-system interactions.

  4. Light-induced copper(II) coordination by a bicyclic tetraaza chelator through a ligand-to-metal charge-transfer reaction.

    Science.gov (United States)

    Holm-Jørgensen, Jacob R; Jensen, Mikael; Bjerrum, Morten J

    2011-12-19

    To enable utilization of the broad potential of copper isotopes in nuclear medicine, rapid and robust chelation of the copper is required. Bowl adamanzanes (bicyclic tetraaza ligands) can form kinetically stable copper complexes, but they are usually formed at low rates unless high pH values and high temperatures are applied. We have investigated the effects of the variation in the pH, different anions, and UV irradiation on the chelation rate. UV spectra of mixtures of Cu(2+) and [2(4).3(1)]adz in water show the existence of a long-lived two-coordinated copper(II) intermediate (only counting coordinated amine groups) at pH above 6. These findings are supported by pH titrations of mixtures of Cu(2+) and [2(4).3(1)]adz in water. Irradiation of this complex in the ligand-to-metal charge-transfer (LMCT) band by a diode-array spectrophotometer leads to photodeprotonation and subsequently to formation of the four-coordinated copper(II) complex at a rate up to 7800-fold higher at 25 °C than in the dark. Anions in the solution were found to have three major effects: competitive inhibition due to Cu(II) binding anions, inhibition of the photoinduced transchelation from UV-absorbing anions, and photoredox inhibition from acido ligands capable of acting as electron donors in LMCT reactions. Dissolved O(2) was also found to result in photoredox inhibition.

  5. Ligand-induced modulation of the free-energy landscape of G protein-coupled receptors explored by adaptive biasing techniques.

    Directory of Open Access Journals (Sweden)

    Davide Provasi

    2011-10-01

    Full Text Available Extensive experimental information supports the formation of ligand-specific conformations of G protein-coupled receptors (GPCRs as a possible molecular basis for their functional selectivity for signaling pathways. Taking advantage of the recently published inactive and active crystal structures of GPCRs, we have implemented an all-atom computational strategy that combines different adaptive biasing techniques to identify ligand-specific conformations along pre-determined activation pathways. Using the prototypic GPCR β2-adrenergic receptor as a suitable test case for validation, we show that ligands with different efficacies (either inverse agonists, neutral antagonists, or agonists modulate the free-energy landscape of the receptor by shifting the conformational equilibrium towards active or inactive conformations depending on their elicited physiological response. Notably, we provide for the first time a quantitative description of the thermodynamics of the receptor in an explicit atomistic environment, which accounts for the receptor basal activity and the stabilization of different active-like states by differently potent agonists. Structural inspection of these metastable states reveals unique conformations of the receptor that may have been difficult to retrieve experimentally.

  6. Inositol Hexaphosphate Down-regulates both Constitutive and Ligand-Induced Mitogenic and Cell Survival Signaling, and Causes Caspase-Mediated Apoptotic Death of Human Prostate Carcinoma PC-3 cells

    Science.gov (United States)

    Gu, Mallikarjuna; Raina, Komal; Agarwal, Chapla; Agarwal, Rajesh

    2009-01-01

    Constitutively active mitogenic and pro-survival signaling cascades due to aberrant expression and interaction of growth factors and their receptors are well documented in human prostate cancer (PCa). EGF and IGF-1 are potent mitogens that regulate proliferation and survival of PCa cells via autocrine and paracrine loops involving both MAPK- and Akt-mediated signaling. Accordingly, here we assessed the effect of inositol hexaphosphate (IP6) on constitutive and ligand (EGF and IGF-1)-induced biological responses and associated signaling cascades in advanced and androgen-independent human PCa PC-3 cells. Treatment of PC-3 cells with 2 mM IP6 strongly inhibited both growth and proliferation and decreased cell viability; similar effects were also observed in other human PCa DU145 and LNCaP cells. IP6 also caused a strong apoptotic death of PC-3 cells together with caspase 3 and PARP cleavage. Mechanistic studies showed that biological effects of IP6 were associated with inhibition of both constitutive and ligand-induced Akt phosphorylation together with a decrease in total Akt levels, but a differential inhibitory effect on MAPKs ERK1/2, JNK1/2 and p38 under constitutive and ligand-activated conditions. Under similar condition, IP6 also inhibited AP-1 DNA binding activity and decreased nuclear levels of both phospho and total c-Fos and c-Jun. Together, these findings for the first time establish IP6 efficacy in inhibiting aberrant EGFR or IGF-1R pathway-mediated sustained growth promoting and survival signaling cascades in advanced and androgen-independent human PCa PC-3 cells, which might have translational implications in advanced human PCa control and management. PMID:19544333

  7. Ligand-independent activation of the arylhydrocarbon receptor by ETK (Bmx) tyrosine kinase helps MCF10AT1 breast cancer cells to survive in an apoptosis-inducing environment.

    Science.gov (United States)

    Fujisawa, Yasuko; Li, Wen; Wu, Dalei; Wong, Patrick; Vogel, Christoph; Dong, Bin; Kung, Hsing-Jien; Matsumura, Fumio

    2011-10-01

    It has been reported that the arylhydrocarbon receptor (AHR) is overexpressed in certain types of breast tumors. However, so far no concrete evidence has been provided yet as to why and how the overexpressed AHR in those cancer cells is functionally activated without exogenous ligands. Here we show that the AHR was functionally activated when estrogen receptor-negative, AHR overexpressing MCF10AT1 human breast cancer cells (designated P20E) were subjected to serum starvation. Transfection of cells with ETK-KQ, a plasmid for kinase-dead epithelial and endothelial tyrosine kinase (ETK), attenuated this AHR activation. Artificial over-expression of ETK in P20E cells through transfection with wild-type ETK plasmid (ETK-wt) caused up-regulation of cytochrome P4501a1 (CYP1A1; a marker of functional activation of AHR). Furthermore, ablation of ETK expression by a specific antisense oligonucleotide or AG879, a specific inhibitor of ETK kinase suppressed activation of AHR induced by omeprazole, a strong ligand-independent activator of AHR. Activation of ETK in those cells conferred them resistance to UVB- as well as doxorubicin-induced apoptosis, both of which were reversed by ETK-KQ. Together, these findings support our conclusion that ETK is the tyrosine kinase responsible for the functional activation of the AHR in these mammary epithelial cells.

  8. Human beta-defensin-2 and -3 enhance pro-inflammatory cytokine expression induced by TLR ligands via ATP-release in a P2X7R dependent manner.

    Science.gov (United States)

    Wanke, Daniela; Mauch-Mücke, Katrin; Holler, Ernst; Hehlgans, Thomas

    2016-11-01

    Our previous results indicate that HBD2 and HBD3 are chemotactic for a broad spectrum of leukocytes in a CCR6- and CCR2-dependent manner. In this study we report that pre-stimulation of primary human macrophages or THP-1 cells with HBD2 or HBD3 results in a synergistic, enhanced expression of pro-inflammatory cytokines and chemokines induced by TLR ligand re-stimulation. Experiments using specific inhibitors of the ATP-gated channel receptor P2X7 or its functional ligand ATP, suggest that the enhanced expression of pro-inflammatory cytokines and chemokines seems to be mediated by P2X7R. Furthermore, our data provide evidence that beta-defensins do not directly interact with P2X7R but rather induce the release of intracellular ATP. Interference with ATP release abrogated the synergistic effect mediated by HBD2 and HBD3 pre-stimulation in THP-1 cells. However, extracellular ATP alone seems not to be sufficient to elicit the enhanced synergistic effect on cytokine and chemokine expression observed by pre-stimulation of primary human macrophages or THP-1 cells with HBD2 or HBD3. Collectively, our findings provide new insights into the molecular mechanisms how HBD2 and HBD3 interact with cells of myeloid origin and demonstrate their immuno-modulating functions during innate immune responses.

  9. Deciphering ligand specificity of a Clostridium thermocellum family 35 carbohydrate binding module (CtCBM35 for gluco- and galacto- substituted mannans and its calcium induced stability.

    Directory of Open Access Journals (Sweden)

    Arabinda Ghosh

    Full Text Available This study investigated the role of CBM35 from Clostridium thermocellum (CtCBM35 in polysaccharide recognition. CtCBM35 was cloned into pET28a (+ vector with an engineered His6 tag and expressed in Escherichia coli BL21 (DE3 cells. A homogenous 15 kDa protein was purified by immobilized metal ion chromatography (IMAC. Ligand binding analysis of CtCBM35 was carried out by affinity electrophoresis using various soluble ligands. CtCBM35 showed a manno-configured ligand specific binding displaying significant association with konjac glucomannan (Ka = 14.3×10(4 M(-1, carob galactomannan (Ka = 12.4×10(4 M(-1 and negligible association (Ka = 12 µM(-1 with insoluble mannan. Binding of CtCBM35 with polysaccharides which was calcium dependent exhibited two fold higher association in presence of 10 mM Ca(2+ ion with konjac glucomannan (Ka = 41×10(4 M(-1 and carob galactomannan (Ka = 30×10(4 M(-1. The polysaccharide binding was further investigated by fluorescence spectrophotometric studies. On binding with carob galactomannan and konjac glucomannan the conformation of CtCBM35 changed significantly with regular 21 nm peak shifts towards lower quantum yield. The degree of association (K a with konjac glucomannan and carob galactomannan, 14.3×10(4 M(-1 and 11.4×10(4 M(-1, respectively, corroborated the findings from affinity electrophoresis. The association of CtCBM35with konjac glucomannan led to higher free energy of binding (ΔG -25 kJ mole(-1 as compared to carob galactomannan (ΔG -22 kJ mole(-1. On binding CtCBM35 with konjac glucomannan and carob galactomannan the hydrodynamic radius (RH as analysed by dynamic light scattering (DLS study, increased to 8 nm and 6 nm, respectively, from 4.25 nm in absence of ligand. The presence of 10 mM Ca(2+ ions imparted stiffer orientation of CtCBM35 particles with increased RH of 4.52 nm. Due to such stiffer orientation CtCBM35 became more thermostable and its melting temperature was

  10. Light-Induced Copper(II) Coordination by a Bicyclic Tetraaza Chelator through a Ligand-to-Metal Charge-Transfer Reaction

    DEFF Research Database (Denmark)

    Holm-Jørgensen, Jacob Rørdam; Jensen, Mikael; Bjerrum, Morten

    2011-01-01

    To enable utilization of the broad potential of copper isotopes in nuclear medicine, rapid and robust chelation of the copper is required. Bowl adamanzanes (bicyclic tetraaza ligands) can form kinetically stable copper complexes, but they are usually formed at low rates unless high pH values...... and high temperatures are applied. We have investigated the effects of the variation in the pH, different anions, and UV irradiation on the chelation rate. UV spectra of mixtures of Cu2+ and [24.31]adz in water show the existence of a longlived two-coordinated copper(II) intermediate (only counting...

  11. Toll-Like Receptor 1/2 and 5 Ligands Enhance the Expression of Cyclin D1 and D3 and Induce Proliferation in Mantle Cell Lymphoma.

    Directory of Open Access Journals (Sweden)

    Katy Mastorci

    Full Text Available Mantle cell lymphoma (MCL is an aggressive B-cell non-Hodgkin's lymphoma with a still undefined etiology. Several lines of evidence are consistent with the possible involvement of peculiar microenvironmental stimuli sustaining tumor cell growth and survival, as the activation of Toll-like receptors (TLR 4 and 9. However, little is known about the contribution of other TLRs of pathogenic relevance in the development of MCL. This study reports evidence that MCL cell lines and primary MCL cells express different levels of TLR2 and TLR5, and that their triggering is able to further activate the Akt, MAPK, and NF-κB signaling cascades, known to be altered in MCL cells. This leads to the enhancement of cyclin D1 and D3 over-expression, occurring at post-translational level through a mechanism that likely involves the Akt/GSK-3α/β pathway. Interestingly, in primary B cells, TLR1/2 or TLR5 ligands increase protein level of cyclin D1, which is not usually expressed in normal B cells, and cyclin D3 when associated with CD40 ligand (CD40L, IL-4, and anti-human-IgM co-stimulus. Finally, the activation of TLR1/2 and TLR5 results in an increased proliferation of MCL cell lines and, in the presence of co-stimulation with CD40L, IL-4, and anti-human-IgM also of primary MCL cells and normal B lymphocytes. These effects befall together with an enhanced IL-6 production in primary cultures. Overall, our findings suggest that ligands for TLR1/2 or TLR5 may provide critical stimuli able to sustain the growth and the malignant phenotype of MCL cells. Further studies aimed at identifying the natural source of these TLR ligands and their possible pathogenic association with MCL are warranted in order to better understand MCL development, but also to define new therapeutic targets for counteracting the tumor promoting effects of lymphoma microenvironment.

  12. Decreased affinity of recombinant human tumor necrosis factor-related apoptosis-inducing ligand (rhTRAIL) D269H/E195R to osteoprotegerin (OPG) overcomes TRAIL resistance mediated by the bone microenvironment.

    Science.gov (United States)

    Bosman, Matthieu C J; Reis, Carlos R; Schuringa, Jan J; Vellenga, Edo; Quax, Wim J

    2014-01-10

    The bone marrow microenvironment provides important signals for the survival and proliferation of hematopoietic and malignant cells. In multiple myeloma, plasma cells are surrounded by stromal cells including osteoblasts. These stromal cells protect multiple myeloma cells from apoptosis induced by chemotherapeutic agents. Osteoprotegerin (OPG), a soluble receptor of the cytokine TNF-related apoptosis-inducing ligand (TRAIL), is secreted by osteoblasts and has been implicated in the prevention of cell death induced by TRAIL in malignant cells. Previously, we have designed death receptor-specific TRAIL variants that induce apoptosis exclusively via one of its death receptors. Here, we have studied in detail the interaction between recombinant human (rhTRAIL) variants and OPG. We show that a DR5-specific variant (rhTRAIL D269H/E195R) displays a significantly decreased affinity to OPG. Furthermore, this rhTRAIL variant shows a much higher activity when compared with rhTRAIL WT and retains its effectiveness in inducing cell death in multiple myeloma cell lines, in the presence of OPG secreted by stromal cells. We also demonstrate that stromal cells are largely insensitive to high concentrations of this rhTRAIL variant. In conclusion, rhTRAIL D269H/E195R is a potential therapy for multiple myeloma due to its high effectiveness and diminished binding to OPG.

  13. Brucella abortus Invasion of Osteocytes Modulates Connexin 43 and Integrin Expression and Induces Osteoclastogenesis via Receptor Activator of NF-κB Ligand and Tumor Necrosis Factor Alpha Secretion.

    Science.gov (United States)

    Pesce Viglietti, Ayelén Ivana; Arriola Benitez, Paula Constanza; Gentilini, María Virginia; Velásquez, Lis Noelia; Fossati, Carlos Alberto; Giambartolomei, Guillermo Hernán; Delpino, María Victoria

    2015-10-12

    Osteoarticular brucellosis is the most common localization of human active disease. Osteocytes are the most abundant cells of bone. They secrete factors that regulate the differentiation of both osteoblasts and osteoclasts during bone remodeling. The aim of this study is to determine if Brucella abortus infection modifies osteocyte function. Our results indicate that B. abortus infection induced matrix metalloproteinase 2 (MMP-2), receptor activator for NF-κB ligand (RANKL), proinflammatory cytokines, and keratinocyte chemoattractant (KC) secretion by osteocytes. In addition, supernatants from B. abortus-infected osteocytes induced bone marrow-derived monocytes (BMM) to undergo osteoclastogenesis. Using neutralizing antibodies against tumor necrosis factor alpha (TNF-α) or osteoprotegerin (OPG), RANKL's decoy receptor, we determined that TNF-α and RANKL are involved in osteoclastogenesis induced by supernatants from B. abortus-infected osteocytes. Connexin 43 (Cx43) and the integrins E11/gp38, integrin-α, integrin-β, and CD44 are involved in cell-cell interactions necessary for osteocyte survival. B. abortus infection inhibited the expression of Cx43 but did not modify the expression of integrins. Yet the expression of both Cx43 and integrins was inhibited by supernatants from B. abortus-infected macrophages. B. abortus infection was not capable of inducing osteocyte apoptosis. However, supernatants from B. abortus-infected macrophages induced osteocyte apoptosis in a dose-dependent manner. Taken together, our results indicate that B. abortus infection could alter osteocyte function, contributing to bone damage.

  14. Ligand modeling and design

    Energy Technology Data Exchange (ETDEWEB)

    Hay, B.P. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    The purpose of this work is to develop and implement a molecular design basis for selecting organic ligands that would be used in the cost-effective removal of specific radionuclides from nuclear waste streams. Organic ligands with metal ion specificity are critical components in the development of solvent extraction and ion exchange processes that are highly selective for targeted radionuclides. The traditional approach to the development of such ligands involves lengthy programs of organic synthesis and testing, which in the absence of reliable methods for screening compounds before synthesis, results in wasted research effort. The author`s approach breaks down and simplifies this costly process with the aid of computer-based molecular modeling techniques. Commercial software for organic molecular modeling is being configured to examine the interactions between organic ligands and metal ions, yielding an inexpensive, commercially or readily available computational tool that can be used to predict the structures and energies of ligand-metal complexes. Users will be able to correlate the large body of existing experimental data on structure, solution binding affinity, and metal ion selectivity to develop structural design criteria. These criteria will provide a basis for selecting ligands that can be implemented in separations technologies through collaboration with other DOE national laboratories and private industry. The initial focus will be to select ether-based ligands that can be applied to the recovery and concentration of the alkali and alkaline earth metal ions including cesium, strontium, and radium.

  15. Ligand modeling and design

    Energy Technology Data Exchange (ETDEWEB)

    Hay, B. [Pacific Northwest Lab., Richland, WA (United States)

    1996-10-01

    The purpose of this work is to develop and implement a molecular design basis for selecting organic ligands that would be used tin applications for the cost-effective removal of specific radionuclides from nuclear waste streams.

  16. Selector-induced dynamic deracemization of a selectand-modified tropos BIPHEPO-ligand: application in the organocatalyzed asymmetric double-aldol-reaction.

    Science.gov (United States)

    Maier, Frank; Trapp, Oliver

    2014-08-11

    Stereolabile interconverting catalysts open up the possibility of directing enantioselectivity in asymmetric synthesis by formation of diastereomeric complexes with chiral auxiliaries and deracemization. However, the stoichiometrically used auxilliaries can significantly limit the potential applications of such systems. We synthesized a new BIPHEPO tropos ligand containing achiral selectands in the backbone, which forms transient diastereomeric associates with amylose-tris-3,5-dimethylphenyl carbamate as a selector and thus deracemizes. The enantiomerically enriched BIPHEPO obtained was successfully used in the organocatalytic asymmetric double aldol addition of substituted methyl ketones to form benzaldehyde. This strategy combines an on-column deracemization with the high stereoinduction of chiral biarylphosphineoxides and opens up new possibilities in the field of self-amplified asymmetric syntheses. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Treating small fiber neuropathy by topical application of a small molecule modulator of ligand-induced GFRα/RET receptor signaling.

    Science.gov (United States)

    Hedstrom, Kristian L; Murtie, Joshua C; Albers, Kathryn; Calcutt, Nigel A; Corfas, Gabriel

    2014-02-11

    Small-fiber neuropathy (SFN) is a disorder of peripheral nerves commonly found in patients with diabetes mellitus, HIV infection, and those receiving chemotherapy. The complexity of disease etiology has led to a scarcity of effective treatments. Using two models of progressive SFN, we show that overexpression of glial cell line-derived neurotrophic factor (GDNF) in skin keratinocytes or topical application of XIB4035, a reported nonpeptidyl agonist of GDNF receptor α1 (GFRα1), are effective treatments for SFN. We also demonstrate that XIB4035 is not a GFRα1 agonist, but rather it enhances GFRα family receptor signaling in conjunction with ligand stimulation. Taken together, our results indicate that topical application of GFRα/RET receptor signaling modulators may be a unique therapy for SFN, and we have identified XIB4035 as a candidate therapeutic agent.

  18. The Role of Selected Flavonols in Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Receptor–1 (TRAIL-R1 Expression on Activated RAW 264.7 Macrophages

    Directory of Open Access Journals (Sweden)

    Monika Warat

    2015-01-01

    Full Text Available Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Receptors (TRAIL-R are an important factor of apoptosis in cancer cells. There are no data about the effect of flavonols on the receptor expression on a surface of macrophage like cells. In this study, the expression level of TRAIL-R1 on murine RAW264.7 macrophages in the presence of selected flavonols: galangin, kaempferol, kaempferide and quercetin, which differ from their phenyl ring substituents, were studied. The expression of TRAIL-R1 death receptors on non-stimulated and lipopolysaccharide (LPS-stimulated macrophages was determined using flow cytometry. The results suggested that compounds being tested can modulate TRAIL-R1 expression and can enhance TRAIL-mediated apoptosis.

  19. Ligand-specific conformational changes in the alpha1 glycine receptor ligand-binding domain

    DEFF Research Database (Denmark)

    Pless, Stephan Alexander; Lynch, Joseph W

    2009-01-01

    indicate that channel opening is accompanied by conformational rearrangements in both beta-sheets. In an attempt to resolve ligand-dependent movements in the ligand-binding domain, we employed voltage-clamp fluorometry on alpha1 glycine receptors to compare changes mediated by the agonist, glycine......, and by the antagonist, strychnine. Voltage-clamp fluorometry involves labeling introduced cysteines with environmentally sensitive fluorophores and inferring structural rearrangements from ligand-induced fluorescence changes. In the inner beta-sheet, we labeled residues in loop 2 and in binding domain loops D and E....... At each position, strychnine and glycine induced distinct maximal fluorescence responses. The pre-M1 domain responded similarly; at each of four labeled positions glycine produced a strong fluorescence signal, whereas strychnine did not. This suggests that glycine induces conformational changes...

  20. Quercetin enhances apoptotic effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in ovarian cancer cells through reactive oxygen species (ROS) mediated CCAAT enhancer-binding protein homologous protein (CHOP)-death receptor 5 pathway

    Science.gov (United States)

    Yi, Liu; Zongyuan, Yang; Cheng, Gong; Lingyun, Zhang; GuiLian, Yu; Wei, Gong

    2014-01-01

    Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has shown efficacy in a phase 2 clinical trial, development of resistance to TRAIL by tumor cells is a major roadblock. We investigated whether quercetin, a flavonoid, can sensitize human ovarian cancer cells to TRAIL. Results indicate that quercetin sensitized cancer cells to TRAIL. The quercetin induced expression of death receptor DR5 but did not affect expression of DR4 in cancer cells. The induction of DR5 was mediated through activation of JNK and through upregulation of a transcription factor CCAAT enhancer-binding protein homologous protein (CHOP); as silencing of these signaling molecules abrogated the effect of quercetin. Upregulation of DR5 was mediated through the generation of reactive oxygen species (ROS), as ROS scavengers reduced the effect of quercetin on JNK activation, CHOP upregulation, DR induction, TRAIL sensitization, downregulated the expression of cell survival proteins and upregulated the proapoptotic proteins. Furthermore, quercetin enhances TRAIL mediated inhibition of tumor growth of human SKOV-3 xenograft was associated with induction of apoptosis, activation of caspase-3, CHOP and DR5. Overall, our data suggest that quercetin enhances apoptotic death of ovarian cancer cells to TRAIL through upregulation of CHOP-induced DR5 expression following ROS mediated endoplasmic reticulum-stress. PMID:24612139

  1. The Paired-box Homeodomain Transcription Factor Pax6 Binds to the Upstream Region of the TRAP Gene Promoter and Suppresses Receptor Activator of NF-κB Ligand (RANKL)-induced Osteoclast Differentiation*

    Science.gov (United States)

    Kogawa, Masakazu; Hisatake, Koji; Atkins, Gerald J.; Findlay, David M.; Enoki, Yuichiro; Sato, Tsuyoshi; Gray, Peter C.; Kanesaki-Yatsuka, Yukiko; Anderson, Paul H.; Wada, Seiki; Kato, Naoki; Fukuda, Aya; Katayama, Shigehiro; Tsujimoto, Masafumi; Yoda, Tetsuya; Suda, Tatsuo; Okazaki, Yasushi; Matsumoto, Masahito

    2013-01-01

    Osteoclast formation is regulated by balancing between the receptor activator of nuclear factor-κB ligand (RANKL) expressed in osteoblasts and extracellular negative regulatory cytokines such as interferon-γ (IFN-γ) and interferon-β (IFN-β), which can suppress excessive bone destruction. However, relatively little is known about intrinsic negative regulatory factors in RANKL-mediated osteoclast differentiation. Here, we show the paired-box homeodomain transcription factor Pax6 acts as a negative regulator of RANKL-mediated osteoclast differentiation. Electrophoretic mobility shift and reporter assays found that Pax6 binds endogenously to the proximal region of the tartrate acid phosphatase (TRAP) gene promoter and suppresses nuclear factor of activated T cells c1 (NFATc1)-induced TRAP gene expression. Introduction of Pax6 retrovirally into bone marrow macrophages attenuates RANKL-induced osteoclast formation. Moreover, we found that the Groucho family member co-repressor Grg6 contributes to Pax6-mediated suppression of the TRAP gene expression induced by NFATc1. These results suggest that Pax6 interferes with RANKL-mediated osteoclast differentiation together with Grg6. Our results demonstrate that the Pax6 pathway constitutes a new aspect of the negative regulatory circuit of RANKL-RANK signaling in osteoclastogenesis and that the augmentation of Pax6 might therefore represent a novel target to block pathological bone resorption. PMID:23990468

  2. The oestrogen metabolite 2-methoxyoestradiol alone or in combination with tumour necrosis factor-related apoptosis-inducing ligand mediates apoptosis in cancerous but not healthy cells of the human endometrium.

    Science.gov (United States)

    Kato, Sumie; Sadarangani, Anil; Lange, Soledad; Villalón, Manuel; Brañes, Jorge; Brosens, Jan J; Owen, Gareth I; Cuello, Mauricio

    2007-06-01

    Cancers of the reproductive tract account for 12% of all malignancies in women. As previous studies have shown that oestrogen metabolites can cause apoptosis, we characterised the effect of oestrogen and oestrogen metabolites on non-cancerous and cancerous human endometrial cells. Herein, we demonstrate that 2-methoxyoestradiol (2ME), but not 17beta-oestradiol, induces apoptosis in cancer cell lines and primary cultured tumours of endometrial origin. In contrast, 2ME had no effect on cell viability of corresponding normal tissue. This ability of 2ME to induce apoptosis does not require oestrogen receptor activation, but is associated with increased entry into the G2/M phases of the cell cycle and the activation of both the intrinsic and the extrinsic apoptotic pathways. The selective behaviour of 2ME on cancerous as opposed to normal tissue may be due to a reduction in 17beta-hydroxysteroid dehydrogenase type II levels in cancer cells and to a differential down-regulation of superoxide dismutase. Furthermore, we demonstrate that pre-treatment with 2ME enhances the sensitivity of reproductive tract cancer cells to the apoptotic drug tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), without the loss in cell viability to normal cells incurred by currently chemotherapeutic drugs. In conclusion, 2ME, alone or in combination with TRAIL, may be an effective treatment for cancers of uterine origin with minimal toxicity to corresponding healthy female reproductive tissue.

  3. A site-directed spin-labeling study of ligand-induced conformational change in the ferric enterobactin receptor, FepA.

    Science.gov (United States)

    Liu, J; Rutz, J M; Klebba, P E; Feix, J B

    1994-11-15

    The ferric enterobactin receptor, FepA, is a TonB-dependent gated porin that transports the siderophore ferric enterobactin across the outer membrane of gram-negative bacteria. We have created two site-directed mutants of Escherichia coli FepA, in both cases introducing a cysteine residue into the putative ligand-binding domain. The introduced cysteines were then modified with nitroxide spin labels for structural and dynamic studies using electron spin resonance (ESR) spectroscopy. The mutants were fully functional, as indicated by their ability to grow under iron-limiting conditions, their uptake of [59Fe]enterobactin, and their sensitivity to colicin B. Labeling of the mutant FepA receptors proceeded easily upon incubation with sulfhydryl-specific spin labels, e.g. MTSL, (1-oxy-2,2,5,5-tetramethylpyrrolidin-3-yl)methyl methanethiosulfonate. In contrast, spin labeling of the two native cysteines (Cys486 and Cys493) within wild-type FepA occurred only after treatment with a thiol reducing agent and partial denaturation in urea, suggesting that the native cysteines are disulfide-linked. ESR spectra showed a high degree of motional restriction for all three sites. Continuous wave (CW) saturation studies indicated that one of the mutationally introduced sites (Cys280) was surface-localized as evidenced by its exposure to the aqueous paramagnetic relaxation agent chromium oxalate and its low accessibility to O2. The other (Cys310) apparently occupies a site near the membrane/aqueous interface. The native cysteines occupy a site tightly packed within the protein structure with low accessibility to both CROX and O2. A shift in both conventional and saturation-transfer ESR spectra of MTSL-labeled E280C and E310C (but not MTSL-labeled wild type) FepA was observed upon addition of ferric enterobactin. The ESR spectral shift was dependent on ferric enterobactin concentration and did not occur with siderophores not recognized by FepA. Ferric enterobactin binding did not alter

  4. Lectin-like domain of thrombomodulin binds to its specific ligand Lewis Y antigen and neutralizes lipopolysaccharide-induced inflammatory response

    Science.gov (United States)

    Shi, Chung-Sheng; Hsiao, Shi-Ming; Kao, Yuan-Chung; Kuo, Kuan-Lin; Ma, Chih-Yuan; Kuo, Cheng-Hsiang; Chang, Bi-Ing; Chang, Chuan-Fa; Lin, Chun-Hung; Wong, Chi-Huey

    2008-01-01

    Thrombomodulin (TM), a widely expressing glycoprotein originally identified in vascular endothelium, is an important cofactor in the protein C anticoagulant system. TM appears to exhibit anti-inflammatory ability through both protein C–dependent and –independent pathways. We presently have demonstrated that recombinant N-terminal lectinlike domain of TM (rTMD1) functions as a protective agent against sepsis caused by Gram-negative bacterial infections. rTMD1 caused agglutination of Escherichia coli and Klebsiella pneumoniae and enhanced the macrophage phagocytosis of these Gram-negative bacteria. Moreover, rTMD1 bound to the Klebsiella pneumoniae and lipopolysaccharide (LPS) by specifically interacting with Lewis Y antigen. rTMD1 inhibited LPS-induced inflammatory mediator production via interference with CD14 and LPS binding. Furthermore, rTMD1 modulated LPS-induced mitogen-activated protein kinase and nuclear factor-κB signaling pathway activations and inducible nitric oxide synthase expression in macrophages. Administration of rTMD1 protected the host by suppressing inflammatory responses induced by LPS and Gram-negative bacteria, and enhanced LPS and bacterial clearance in sepsis. Thus, rTMD1 can be used to defend against bacterial infection and inhibit LPS-induced inflammatory responses, suggesting that rTMD1 may be valuable in the treatment of severe inflammation in sepsis, especially in Gram-negative bacterial infections. PMID:18711002

  5. A cardiac-specific robotized cellular assay identified families of human ligands as inducers of PGC-1α expression and mitochondrial biogenesis.

    Directory of Open Access Journals (Sweden)

    Matthieu Ruiz

    Full Text Available BACKGROUND: Mitochondrial function is dramatically altered in heart failure (HF. This is associated with a decrease in the expression of the transcriptional coactivator PGC-1α, which plays a key role in the coordination of energy metabolism. Identification of compounds able to activate PGC-1α transcription could be of future therapeutic significance. METHODOLOGY/PRINCIPAL FINDINGS: We thus developed a robotized cellular assay to screen molecules in order to identify new activators of PGC-1α in a cardiac-like cell line. This screening assay was based on both the assessment of activity and gene expression of a secreted luciferase under the control of the human PGC-1α promoter, stably expressed in H9c2 cells. We screened part of a library of human endogenous ligands and steroid hormones, B vitamins and fatty acids were identified as activators of PGC-1α expression. The most responsive compounds of these families were then tested for PGC-1α gene expression in adult rat cardiomyocytes. These data highly confirmed the primary screening, and the increase in PGC-1α mRNA correlated with an increase in several downstream markers of mitochondrial biogenesis. Moreover, respiration rates of H9c2 cells treated with these compounds were increased evidencing their effectiveness on mitochondrial biogenesis. CONCLUSIONS/SIGNIFICANCE: Using our cellular reporter assay we could identify three original families, able to activate mitochondrial biogenesis both in cell line and adult cardiomyocytes. This first screening can be extended to chemical libraries in order to increase our knowledge on PGC-1α regulation in the heart and to identify potential therapeutic compounds able to improve mitochondrial function in HF.

  6. Peptide insertions in domain 4 of hbeta(c), the shared signalling receptor subunit for GM-CSF, IL3 and IL5, induce ligand-independent activation.

    Science.gov (United States)

    Jones, K L; Bagley, C J; Butcher, C; Barry, S C; Vadas, M A; D'Andrea, R J

    2001-06-21

    A mutant form of the common beta-subunit of the GM-CSF, interleukin-3 (IL3) and IL5 receptors is activated by a 37 residue duplicated segment which includes the WSXWS motif and an adjacent, highly conserved, aliphatic/basic element. Haemopoietic expression of this mutant, hbeta(c)FIDelta, in mice leads to myeloproliferative disease. To examine the mechanism of activation of this mutant we targetted the two conserved motifs in each repeat for mutagenesis. Here we show that this mutant exhibits constitutive activity in BaF-B03 cells in the presence of mouse or human GM-CSF receptor alpha-subunit (GMRalpha) and this activity is disrupted by mutations of the conserved motifs in the first repeat. In the presence of these mutations the receptor reverts to an alternative conformation which retains responsiveness to human IL3 in a CTLL cell line co-expressing the human IL3 receptor alpha-subunit (hIL3Ralpha). Remarkably, the activated conformation is maintained in the presence of substitutions, deletions or replacement of the second repeat. This suggests that activation occurs due to insertion of extra sequence after the WSXWS motif and is not dependent on the length or specific sequence of the insertion. Thus hbeta(c) displays an ability to fold into functional receptor conformations given insertion of up to 37 residues in the membrane-proximal region. Constitutive activation most likely results from a specific conformational change which alters a dormant, inactive receptor complex, permitting functional association with GMRalpha and ligand-independent mitogenic signalling.

  7. Receptor Activator of Nuclear Factor Kappa-B Ligand-Induced Local Osteoporotic Canine Mandible Model for the Evaluation of Peri-Implant Bone Regeneration.

    Science.gov (United States)

    Chang, Ah Ryum; Cho, Tae Hyung; Hwang, Soon Jung

    2017-08-24

    The canine mandible is useful for studying bone regeneration after dental implant placement. However, it is limited in investigations of peri-implant osteogenesis under osteoporotic conditions due to the insignificant osteoporotic effect of ovariectomy. This study aimed at establishing a local osteoporotic model without ovariectomy by using receptor activator of nuclear factor kappa-B ligand (RANKL) in a canine mandible model. This new model was used to evaluate the effects of injectable β-tricalcium phosphate (TCP) microsphere bone grafts on peri-implant bone regeneration under osteoporotic conditions with combinations of recombinant human bone morphogenetic protein-2 (rhBMP-2). A local osteoporotic canine mandible model was designed by creating a hole in the mandibular alveolar bone, then implanting a collagen sponge soaked with 20, 40, or 60 μg RANKL into the hole, and leaving it for 2 weeks. After the establishment of the dose for maximum osteoporotic bone loss at 40 μg of RANKL, the main surgery was performed. RANKL-soaked collagen sponges were removed, and dental implants were placed with bone grafts in five groups: implant only, TCP, and TCP + rhBMP-2 at 5, 15, and 45 μg. Peri-implant bone generation was determined by radiologic and histologic evaluations at 6 weeks after dental implant placement. On performing micro-computed tomography analysis, the group with TCP + 5 μg rhBMP-2 showed the highest bone volume than the other groups and a 22% increase (p model was useful for peri-implant bone regeneration under osteoporotic conditions such as those found in geriatric patients. The injectable β-TCP bone grafts used in this study were effective in peri-implant bone generation under osteoporotic conditions, and their efficiency was enhanced at 5 μg BMP-2 compared with higher concentrations of BMP-2.

  8. Identification of specific sites in the third intracellular loop and carboxyl terminus of the Bombyx mori PBAN receptor crucial for ligand-induced internalization

    Science.gov (United States)

    Sex pheromone production in most moths is mediated by the pheromone biosynthesis activating neuropeptide receptor (PBANR). Similar to other rhodopsin-like G protein-coupled receptors, the silkmoth Bombyx mori PBANR (BmPBANR) undergoes agonist-induced internalization. Despite interest in developing...

  9. Application of Near-Infrared and Fourier Transform Infrared Spectroscopy in the Characterization of Ligand-Induced Conformation Changes in Folate Binding Protein Purified from Bovine Milk

    DEFF Research Database (Denmark)

    Bruun, Susanne Wrang; Holm, Jan; Hansen, Steen Ingemann;

    2006-01-01

    Fourier transform infrared (FT-IR) and near-infrared (NIR) spectroscopy have been applied to detect structural alterations in folate binding protein (FBP) induced by ligation in different buffer types. The amide I region pointed to a beta-sheet to alpha-helix transition upon ligation in acetate...

  10. Hydrodynamic Gene Delivery of Interleukin-22 Protects the Mouse Liver from Concanavalin A-, Carbon Tetrachloride-, and Fas Ligand-Induced Injury via Activation of STAT3

    Institute of Scientific and Technical Information of China (English)

    Hongna Pan; Feng Hong; Svetlana Radaeva; Bin Gao

    2004-01-01

    Interleukin-22 (IL-22) is a recently identified T cell-derived cytokine whose biological significance remains obscure. Previously, we have shown that IL-22 plays a protective role in T cell-mediated hepatitis induced by Concanavalin A (Con A), acting as a survival factor for hepatocytes. In the present paper, we demonstrate that hydrodynamic gene delivery of IL-22 cDNA driven either by a liver-specific albumin promoter or a human cytomegalovirus (CMV) promoter results in IL-22 protein expression, STAT3 activation, and expression of several anti-apoptotic proteins, including Bcl-xL, Bcl-2, and Mcl-1 in the liver. Immunohistochemical analysis reveals that IL-22 protein expression is mainly detected in the cytoplasm of hepatocytes. Overexpression of IL-22 by hydrodynamic gene delivery significantly protects against liver injury, necrosis, and apoptosis induced by administration of Con A, carbon tetrachloride (CCl4), or the Fas agonist Jo-2 mAb. Western blot analyses show that overexpression of IL-22 significantly enhances activation of STAT3 and expression of Bcl-xL, Bcl-2,and Mcl-1 proteins in liver injury induced by Con A. In conclusion, hydrodynamic gene delivery of IL-22 protects against liver injury induced by a variety of toxins, suggesting the therapeutic potential of IL-22 in treating human liver disease. Cellular & Molecular Immunology. 2004;1(1):43-49.

  11. Olefin Metathesis Mediated By: - Schiff Base Ru-Alkylidenes -Ru-Alkylidenes Bearing Unsymmetrical NH Ligands

    Science.gov (United States)

    Monsaert, Stijn; Voort, Pascal Van Der; Ledoux, Nele; Allaert, Bart; Drozdzak, Renata; Verpoort, Francis

    The classic Grubbs second-generation complex 2 was modified through 1. The introduction of a bidentate Schiff base ligand 2. Changes in the amino side groups of the NHC ligand Representative olefin metathesis test reactions show the effects induced by the ligand modifications and demonstrate some interesting new properties of the described catalysts. catalysts.

  12. Ligand and electrically induced acitivation patterns in myenteric neuronal networks. Confocal calcium imaging as a bridge between basic and human physiology.

    Science.gov (United States)

    Bisschops, R

    2008-01-01

    Confocal imaging in combination with fluorescent calcium indicators provides the possibility to study neuronal activation in entire neuronal networks. The experiments presented in this essay aimed at applying confocal calcium imaging to study activation patterns in neuronal networks of myenteric ganglia in situ. First we studied the response to electrical train stimulation (ETS). ETS induced Ca2+ transients in 52.2% and 65.4% of the neurons when applied orally and aborally respectively. We observed more responses during aboral ETS which is not in line with the hypothesis of neuronal polarity, suggesting complex neuronal activation patterns and neuronal interaction in ETS-induced activation in myenteric ganglia. We demonstrated that ghrelin has a direct excitatory effect on myenteric neurons in situ via ghrelin receptor activation. Ghrelin induced Ca2+ transients in one third of the myenteric neurons, involving release of Ca2+ from intracellular stores and direct GHS-receptor activation. We found that CRF activates one fifth of the myenteric neurons, via CRF1 receptor activation. These CRF induced Ca2+ signals involved somatic influx through (mainly R-type) voltage operated Ca2+ channels. Finally we set up human studies in healthy volunteers and dyspeptic patients to test the effect of ghrelin on gastrointestinal motility. Intravenous administration of ghrelin induced a premature phase 3 activity front that originated in the stomach and an increase in gastric tone. Ghrelin decreased gastric emptying time for fluids and reduced symptom scores for fullness and pain. These studies provide further evidence for a role of ghrelin in the regulation of gastrointestinal motility, and possibly provide new therapeutic approaches. Our studies show that confocal calcium imaging allows to assess neuronal activation of myenteric neurons. The influence of new hormones or new pharmaceutical compounds on the myenteric plexus can hereby be easily assessed.

  13. Dendrobium moniliforme Exerts Inhibitory Effects on Both Receptor Activator of Nuclear Factor Kappa-B Ligand-Mediated Osteoclast Differentiation in Vitro and Lipopolysaccharide-Induced Bone Erosion in Vivo.

    Science.gov (United States)

    Baek, Jong Min; Kim, Ju-Young; Ahn, Sung-Jun; Cheon, Yoon-Hee; Yang, Miyoung; Oh, Jaemin; Choi, Min Kyu

    2016-03-01

    Dendrobium moniliforme (DM) is a well-known plant-derived extract that is widely used in Oriental medicine. DM and its chemical constituents have been reported to have a variety of pharmacological effects, including anti-oxidative, anti-inflammatory, and anti-tumor activities; however, no reports discuss the beneficial effects of DM on bone diseases such as osteoporosis. Thus, we investigated the relationship between DM and osteoclasts, cells that function in bone resorption. We found that DM significantly reduced receptor activator of nuclear factor kappa-B ligand (RANKL)-induced tartrate-resistant acid phosphatase (TRAP)-positive osteoclast formation; DM directly induced the down-regulation of c-Fos and nuclear factor of activated T cells c1 (NFATc1) without affecting other RANKL-dependent transduction pathways. In the later stages of osteoclast maturation, DM negatively regulated the organization of filamentous actin (F-actin), resulting in impaired bone-resorbing activity by the mature osteoclasts. In addition, micro-computed tomography (μ-CT) analysis of the murine model revealed that DM had a beneficial effect on lipopolysaccharide (LPS)-mediated bone erosion. Histological analysis showed that DM attenuated the degradation of trabecular bone matrix and formation of TRAP-positive osteoclasts in bone tissues. These results suggest that DM is a potential candidate for the treatment of metabolic bone disorders such as osteoporosis.

  14. Inhibition of osteocyte apoptosis prevents the increase in osteocytic receptor activator of nuclear factor κB ligand (RANKL) but does not stop bone resorption or the loss of bone induced by unloading.

    Science.gov (United States)

    Plotkin, Lilian I; Gortazar, Arancha R; Davis, Hannah M; Condon, Keith W; Gabilondo, Hugo; Maycas, Marta; Allen, Matthew R; Bellido, Teresita

    2015-07-31

    Apoptosis of osteocytes and osteoblasts precedes bone resorption and bone loss with reduced mechanical stimulation, and receptor activator of NF-κB ligand (RANKL) expression is increased with unloading in mice. Because osteocytes are major RANKL producers, we hypothesized that apoptotic osteocytes signal to neighboring osteocytes to increase RANKL expression, which, in turn, increases osteoclastogenesis and bone resorption. The traditional bisphosphonate (BP) alendronate (Aln) or IG9402, a BP analog that does not inhibit resorption, prevented the increase in osteocyte apoptosis and osteocytic RANKL expression. The BPs also inhibited osteoblast apoptosis but did not prevent the increase in osteoblastic RANKL. Unloaded mice exhibited high serum levels of the bone resorption marker C-telopeptide fragments of type I collagen (CTX), elevated osteoclastogenesis, and increased osteoclasts in bone. Aln, but not IG9402, prevented all of these effects. In addition, Aln prevented the reduction in spinal and femoral bone mineral density, spinal bone volume/tissue volume, trabecular thickness, mechanical strength, and material strength induced by unloading. Although IG9402 did not prevent the loss of bone mass, it partially prevented the loss of strength, suggesting a contribution of osteocyte viability to strength independent of bone mass. These results demonstrate that osteocyte apoptosis leads to increased osteocytic RANKL. However, blockade of these events is not sufficient to restrain osteoclast formation, inhibit resorption, or stop bone loss induced by skeletal unloading.

  15. THE EFFECT OF SEROTONIN 5-HT1A, 5-HT2 RECEPTOR LIGANDS, KETOPROFEN AND THEIR COMBINATION IN MODELS OF INDUCED PAIN IN MICE.

    Science.gov (United States)

    Zygmunt, Małgorzata; Chłoń-Rzepa, Grażyna; Sapa, Jacek

    2015-01-01

    The present study was carried out to investigate the effects of the 7-(3-chlorophenyl)piperazinylalkyl derivatives of 8-alkoxypurine-2,6-dione (compounds 1-4) in two animal models of induced pain and to compare their effects with ketoprofen and with their combination. All experiments were performed on albino mice. Mice were evaluated for their responsiveness to noxious stimuli using: the hot-plate test and the phenylbenzo-quinone-induced writhing test. All compounds showed analgesic activity only in the writhing test. The analgesic activities of compounds 3 and 4 were similar to ketoprofen. The compounds slightly increased the analgesic effect of ketoprofen when used in combination in the visceral type of pain. The possible mechanisms of the antinociceptive effect of these compounds are thought to involve the activation of analgesic effect mediated by the serotonergic pathways or combination of this mechanism with other important mediators playing a role in pain modulation.

  16. Peroxisome Proliferator Activator Receptor (PPAR-γ Ligand, but Not PPAR-α, Ameliorates Cyclophosphamide-Induced Oxidative Stress and Inflammation in Rat Liver

    Directory of Open Access Journals (Sweden)

    Azza A. K. El-Sheikh

    2014-01-01

    Full Text Available Hepatoprotective potential of peroxisome proliferator activator receptor (PPAR-α and -γ agonists, fenofibrate (FEN, and pioglitazone (PIO, respectively, against cyclophosphamide (CP-induced toxicity has been investigated in rat. FEN and PIO (150 and 10 mg/kg/day, resp. were given orally for 4 weeks. In separate groups, CP (150 mg/kg, i.p. was injected as a single dose 5 days before the end of experiment, with or without either PPAR agonist. CP induced hepatotoxicity, as it caused histopathological alterations, with increased serum alanine and aspartate transaminases, total bilirubin, albumin, alkaline phosphatase and lactate dehydrogenase. CP caused hepatic oxidative stress, indicated by decrease in tissue reduced glutathione, with increase in malondialdehyde and nitric oxide levels. CP also caused decrease in hepatic antioxidant enzyme levels, including catalase, superoxide dismutase, glutathione peroxidase, and glutathione S-transferase. Furthermore, CP increased serum and hepatic levels of the inflammatory marker tumor necrosis factor (TNF-α, evaluated using ELISA. Preadministration of PIO, but not FEN, prior to CP challenge improved hepatic function and histology, and significantly reversed oxidative and inflammatory parameters. In conclusion, activation of PPAR-γ, but not PPAR-α, conferred protection against CP-induced hepatotoxicity, via activation of antioxidant and anti-inflammatory mechanisms, and may serve as supplement during CP chemotherapy.

  17. Ligand fitting with CCP4

    Science.gov (United States)

    2017-01-01

    Crystal structures of protein–ligand complexes are often used to infer biology and inform structure-based drug discovery. Hence, it is important to build accurate, reliable models of ligands that give confidence in the interpretation of the respective protein–ligand complex. This paper discusses key stages in the ligand-fitting process, including ligand binding-site identification, ligand description and conformer generation, ligand fitting, refinement and subsequent validation. The CCP4 suite contains a number of software tools that facilitate this task: AceDRG for the creation of ligand descriptions and conformers, Lidia and JLigand for two-dimensional and three-dimensional ligand editing and visual analysis, Coot for density interpretation, ligand fitting, analysis and validation, and REFMAC5 for macromolecular refinement. In addition to recent advancements in automatic carbohydrate building in Coot (LO/Carb) and ligand-validation tools (FLEV), the release of the CCP4i2 GUI provides an integrated solution that streamlines the ligand-fitting workflow, seamlessly passing results from one program to the next. The ligand-fitting process is illustrated using instructive practical examples, including problematic cases such as post-translational modifications, highlighting the need for careful analysis and rigorous validation. PMID:28177312

  18. Superior serum half life of albumin tagged TNF ligands

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Nicole [Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Wuerzburg, Roentgenring 11, 97070 Wuerzburg (Germany); Schneider, Britta; Pfizenmaier, Klaus [Institute of Cell Biology and Immunology, University of Stuttgart, Allmandring 31, 70569 Stuttgart (Germany); Wajant, Harald, E-mail: harald.wajant@mail.uni-wuerzburg.de [Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Wuerzburg, Roentgenring 11, 97070 Wuerzburg (Germany)

    2010-06-11

    Due to their immune stimulating and apoptosis inducing properties, ligands of the TNF family attract increasing interest as therapeutic proteins. A general limitation of in vivo applications of recombinant soluble TNF ligands is their notoriously rapid clearance from circulation. To improve the serum half life of the TNF family members TNF, TWEAK and TRAIL, we genetically fused soluble variants of these molecules to human serum albumin (HSA). The serum albumin-TNF ligand fusion proteins were found to be of similar bioactivity as the corresponding HSA-less counterparts. Upon intravenous injection (i.v.), serum half life of HSA-TNF ligand fusion proteins, as determined by ELISA, was around 15 h as compared to approximately 1 h for all of the recombinant control TNF ligands without HSA domain. Moreover, serum samples collected 6 or 24 h after i.v. injection still contained high TNF ligand bioactivity, demonstrating that there is only limited degradation/inactivation of circulating HSA-TNF ligand fusion proteins in vivo. In a xenotransplantation model, significantly less of the HSA-TRAIL fusion protein compared to the respective control TRAIL protein was required to achieve inhibition of tumor growth indicating that the increased half life of HSA-TNF ligand fusion proteins translates into better therapeutic action in vivo. In conclusion, our data suggest that genetic fusion to serum albumin is a powerful and generally applicable mean to improve bioavailability and in vivo activity of TNF ligands.

  19. Comparison of in vivo binding properties of the 18-kDa translocator protein (TSPO) ligands [{sup 18}F]PBR102 and [{sup 18}F]PBR111 in a model of excitotoxin-induced neuroinflammation

    Energy Technology Data Exchange (ETDEWEB)

    Callaghan, P.D.; Gregoire, M.C. [Australian Nuclear Science and Technology Organisation, ANSTO LifeSciences, Kirrawee DC, NSW (Australia); University of Sydney, Brain and Mind Research Institute, Sydney (Australia); University of Sydney, Discipline of Medical Radiation Sciences, Sydney (Australia); Wimberley, C.A.; Rahardjo, G.L.; Berghofer, P.J.; Zahra, D. [Australian Nuclear Science and Technology Organisation, ANSTO LifeSciences, Kirrawee DC, NSW (Australia); University of Sydney, Brain and Mind Research Institute, Sydney (Australia); Pham, T.Q.; Jackson, T.; Wyatt, N.; Greguric, I.; Howell, N.R.; Loc' h, C. [Australian Nuclear Science and Technology Organisation, ANSTO LifeSciences, Kirrawee DC, NSW (Australia); Bourdier, T.; Mattner, F.; Katsifis, A. [Australian Nuclear Science and Technology Organisation, ANSTO LifeSciences, Kirrawee DC, NSW (Australia); Royal Prince Alfred Hospital, Department of Molecular Imaging, Sydney (Australia); Siegele, R.; Pastuovic, Z. [Institute for Environmental Research, Centre for Accelerator Science, ANSTO, Sydney (Australia)

    2015-01-15

    The in vivo binding parameters of the novel imidazopyridine TSPO ligand [{sup 18}F]PBR102 were assessed and compared with those of [{sup 18}F]PBR111 in a rodent model of neuroinflammation. The validity of the key assumptions of the simplified reference tissue model (SRTM) for estimation of binding potential (BP) was determined, with validation against a two-tissue compartment model (2TC). Acute neuroinflammation was assessed 7 days after unilateral stereotaxic administration of (R,S)-α-amino-3-hydroxy-5-methyl-4-isoxazolopropionique (AMPA) in anaesthetized adult Wistar rats. Anaesthetized rats were implanted with a femoral arterial cannula then injected with a low mass of [{sup 18}F]PBR102 or [{sup 18}F]PBR111 and dynamic images were acquired over 60 min using an INVEON PET/CT camera. Another population of rats underwent the same PET protocol after pretreatment with a presaturating mass of the same unlabelled tracer (1 mg/kg) to assess the validity of the reference region for SRTM analysis. Arterial blood was sampled during imaging, allowing pharmacokinetic determination of radiotracer concentrations. Plasma activity concentration-time curves were corrected for unchanged tracer based on metabolic characterization experiments in a separate cohort of Wistar rats. The stability of neuroinflammation in both imaging cohorts was assessed by [{sup 125}I] CLINDE TSPO quantitative autoradiography, OX42/GFAP immunohistochemistry, Fluoro-Jade C histology, and elemental mapping using microparticle-induced x-ray emission spectroscopy. The BP of each ligand were assessed in the two cohorts of lesioned animals using both SRTM and a 2TC with arterial parent compound concentration, coupled with the results from the presaturation cohort for comparison and validation of the SRTM. The BPs of [{sup 18}F]PBR102 [{sup 18}F]PBR111 were equivalent, with improved signal-to-noise ratio and sensitivity compared with [{sup 11}C]PK11195. The presaturation study showed differences in the volume

  20. Angiotensin II type 2 receptor ligand PD123319 attenuates hyperoxia-induced lung and heart injury at a low dose in newborn rats.

    Science.gov (United States)

    Wagenaar, Gerry T M; Sengers, Rozemarijn M A; Laghmani, El Houari; Chen, Xueyu; Lindeboom, Melissa P H A; Roks, Anton J M; Folkerts, Gert; Walther, Frans J

    2014-08-01

    Intervening in angiotensin (Ang)-II type 2 receptor (AT2) signaling may have therapeutic potential for bronchopulmonary dysplasia (BPD) by attenuating lung inflammation and preventing arterial hypertension (PAH)-induced right ventricular hypertrophy (RVH). We first investigated the role of AT2 inhibition with PD123319 (0.5 and 2 mg·kg(-1)·day(-1)) on the beneficial effect of AT2 agonist LP2-3 (5 μg/kg twice a day) on RVH in newborn rats with hyperoxia-induced BPD. Next we determined the cardiopulmonary effects of PD123319 (0.1 mg·kg(-1)·day(-1)) in two models: early treatment during continuous exposure to hyperoxia for 10 days and late treatment starting on day 6 in rat pups exposed postnatally to hyperoxia for 9 days, followed by a 9-day recovery period in room air. Parameters investigated included lung and heart histopathology, fibrin deposition, vascular leakage, and differential mRNA expression. Ten days of coadministration of LP2-3 and PD123319 abolished the beneficial effects of LP2-3 on RVH in experimental BPD. In the early treatment model PD123319 attenuated cardiopulmonary injury by reducing alveolar septal thickness, pulmonary influx of inflammatory cells, including macrophages and neutrophils, medial wall thickness of small arterioles, and extravascular collagen III deposition, and by preventing RVH. In the late treatment model PD123319 diminished PAH and RVH, demonstrating that PAH is reversible in the neonatal period. At high concentrations PD123319 blocks the beneficial effects of the AT2-agonist LP2-3 on RVH. At low concentrations PD123319 attenuates cardiopulmonary injury by reducing pulmonary inflammation and fibrosis and preventing PAH-induced RVH but does not affect alveolar and vascular development in newborn rats with experimental BPD.

  1. Stimulation of macrophages with the β-glucan produced by aureobasidium pullulans promotes the secretion of tumor necrosis factor-related apoptosis inducing ligand (TRAIL.

    Directory of Open Access Journals (Sweden)

    Koji Kawata

    Full Text Available A β-glucan produced by Aureobasidium pullulans (AP-PG is consisting of a β-(1,3-linked main chain with β-(1,6-linked glucose side residues. Various β-glucans consisting of β-(1,3-linked main chain including AP-PG are believed to exhibit anti-tumor activities, and actually, anti-tumor activities of AP-PG in mice have been demonstrated. In this study, we demonstrate that stimulation with AP-PG induces TRAIL expression in mouse and human macrophage-like cell lines. TRAIL is known to be a cytokine which specifically induces apoptosis in transformed cells, but not in untransformed cells. The expression of TRAIL mRNA after stimulation with AP-PG was increased in RAW264.7 cells, Mono Mac 6 cells, and macrophage-differentiated THP-1 cells. The mRNA expression of TNF-α and FasL is only weakly increased after stimulation with AP-PG. The induction activity of TRAIL by curdlan, a bacterial β-glucan, was very similar to that by AP-PG in RAW264.7 cells, but weaker in macrophage-differentiated THP-1 cells. Activation of caspases was found in HeLa cells after treatment with the supernatant of cultured medium from AP-PG-stimulated Mono Mac 6 cells, and was inhibited by the anti-TRAIL neutralizing antibody. These findings suggest that the stimulation with AP-PG effectively induces TRAIL in macrophages, and that it may be related to apoptosis induction of tumor cells.

  2. Application of Near-Infrared and Fourier Transform Infrared Spectroscopy in the Characterization of Ligand-Induced Conformation Changes in Folate Binding Protein Purified from Bovine Milk

    DEFF Research Database (Denmark)

    Bruun, Susanne Wrang; Holm, Jan; Hansen, Steen Ingemann

    2006-01-01

    Fourier transform infrared (FT-IR) and near-infrared (NIR) spectroscopy have been applied to detect structural alterations in folate binding protein (FBP) induced by ligation in different buffer types. The amide I region pointed to a beta-sheet to alpha-helix transition upon ligation in acetate...... indicated similar changes at the two pH values. Therefore, we suggest that FT-IR and NIR spectroscopy may complement each other, such that the two techniques in combination may give information on all three types of protein conformational changes. While the secondary structure changes are revealed by FT...

  3. Recipient myeloid-derived immunomodulatory cells induce PD-1 ligand-dependent donor CD4+Foxp3+ regulatory T cell proliferation and donor-recipient immune tolerance after murine nonmyeloablative bone marrow transplantation.

    Science.gov (United States)

    van der Merwe, Marie; Abdelsamed, Hossam A; Seth, Aman; Ong, Taren; Vogel, Peter; Pillai, Asha B

    2013-12-01

    We showed previously that nonmyeloablative total lymphoid irradiation/rabbit anti-thymocyte serum (TLI/ATS) conditioning facilitates potent donor-recipient immune tolerance following bone marrow transplantation (BMT) across MHC barriers via recipient invariant NKT (iNKT) cell-derived IL-4-dependent expansion of donor Foxp3(+) naturally occurring regulatory T cells (nTregs). In this study, we report a more specific mechanism. Wild-type (WT) BALB/c (H-2(d)) hosts were administered TLI/ATS and BMT from WT or STAT6(-/-) C57BL/6 (H-2(b)) donors. Following STAT6(-/-) BMT, donor nTregs demonstrated no loss of proliferation in vivo, indicating that an IL-4-responsive population in the recipient, rather than the donor, drives donor nTreg proliferation. In graft-versus-host disease (GVHD) target organs, three recipient CD11b(+) cell subsets (Gr-1(high)CD11c(-), Gr-1(int)CD11c(-), and Gr-1(low)CD11c(+)) were enriched early after TLI/ATS + BMT versus total body irradiation/ATS + BMT. Gr-1(low)CD11c(+) cells induced potent H-2K(b+)CD4(+)Foxp3(+) nTreg proliferation in vitro in 72-h MLRs. Gr-1(low)CD11c(+) cells were reduced significantly in STAT6(-/-) and iNKT cell-deficient Jα18(-/-) BALB/c recipients after TLI/ATS + BMT. Depletion of CD11b(+) cells resulted in severe acute GVHD, and adoptive transfer of WT Gr-1(low)CD11c(+) cells to Jα18(-/-) BALB/c recipients of TLI/ATS + BMT restored day-6 donor Foxp3(+) nTreg proliferation and protection from CD8 effector T cell-mediated GVHD. Blockade of programmed death ligand 1 and 2, but not CD40, TGF-β signaling, arginase 1, or iNOS, inhibited nTreg proliferation in cocultures of recipient-derived Gr-1(low)CD11c(+) cells with donor nTregs. Through iNKT-dependent Th2 polarization, myeloid-derived immunomodulatory dendritic cells are expanded after nonmyeloablative TLI/ATS conditioning and allogeneic BMT, induce PD-1 ligand-dependent donor nTreg proliferation, and maintain potent graft-versus-host immune tolerance.

  4. Inhibitory effects of ginkgolide B on CD40 Ligand expression in collagen-induced platelet activation%银杏内酯B抑制血小板CD40Ligand表达的分子机制研究

    Institute of Scientific and Technical Information of China (English)

    闫琰; 赵革新; 陈北冬; 鲍利; 吴伟; 齐若梅

    2012-01-01

    目的 探讨银杏内酯B(ginkgolide B)对活化血小板CD40 Ligand(CD40L)的影响以及相关的分子机制.方法 取正常人血分离血小板,用不同浓度银杏内酯B孵育血小板5 min,然后用胶原(collagen)刺激血小板活化.用Western blot分析PI3K表达,Akt磷酸化,CD40L的变化.结果 ①用collagen刺激血小板聚集,银杏内酯B(0.2、0.4、0.6 g*L-1)预处理血小板5 min,血小板聚集率明显降低,聚集率分别为77%,60%和48%.②Western blot结果显示胶原刺激血小板活化后CD40L表达明显增加,银杏内酯B以剂量依赖方式抑制了CD40L表达.③银杏内酯B对胶原刺激的血小板PI3K表达无明显影响.④collagen刺激血小板活化后Akt的磷酸化增加,银杏内酯B抑制了Akt磷酸化.结论 银杏内酯B能够有效抑制collagen诱导的血小板聚集以及CD40L的表达,并明显抑制了Akt磷酸化,表明银杏内酯B能够通过PI3K/Akt信号传导通路抑制血小板活化.%Aim To investigate the effects of ginkgolide B on the CD40Ligand ( CD40L ) expression in collagen-induced platelet activation and the related mechanism. Methods Anti-coagulated blood was collected from health donor. Platelets were isolated through cen-trifugation. Platelets were pre-incubated by the various concentrations of ginkgolide B for 5 min, then platelets were stimulated by collagen. Protein expression was detected by Western blot. Results 1. 10 mg · L-1 of collagen induced platelet aggregation, and 0. 2 g · L-1,0. 4 g · L-1 and 0. 6 g · L-1 of ginkgolide B potently inhibited platelet aggregation in a dose-dependent manner. 2. The expression of CD40L was increased in collagen-induced platelet activation. Ginkgolide B significantly attenuated the increase of CD40L expression in activated platelets. 3. Ginkgolide B had no effect on PI3K expression in collagen-induced platelet activation. 4. Ginkgolide B obviously abolished Akt phospho-rylation in activated platelets. Conclusions Ginkgolide B can

  5. LigandRNA: computational predictor of RNA-ligand interactions.

    Science.gov (United States)

    Philips, Anna; Milanowska, Kaja; Lach, Grzegorz; Bujnicki, Janusz M

    2013-12-01

    RNA molecules have recently become attractive as potential drug targets due to the increased awareness of their importance in key biological processes. The increase of the number of experimentally determined RNA 3D structures enabled structure-based searches for small molecules that can specifically bind to defined sites in RNA molecules, thereby blocking or otherwise modulating their function. However, as of yet, computational methods for structure-based docking of small molecule ligands to RNA molecules are not as well established as analogous methods for protein-ligand docking. This motivated us to create LigandRNA, a scoring function for the prediction of RNA-small molecule interactions. Our method employs a grid-based algorithm and a knowledge-based potential derived from ligand-binding sites in the experimentally solved RNA-ligand complexes. As an input, LigandRNA takes an RNA receptor file and a file with ligand poses. As an output, it returns a ranking of the poses according to their score. The predictive power of LigandRNA favorably compares to five other publicly available methods. We found that the combination of LigandRNA and Dock6 into a "meta-predictor" leads to further improvement in the identification of near-native ligand poses. The LigandRNA program is available free of charge as a web server at http://ligandrna.genesilico.pl.

  6. Analysis of macromolecules, ligands and macromolecule-ligand complexes

    Science.gov (United States)

    Von Dreele, Robert B [Los Alamos, NM

    2008-12-23

    A method for determining atomic level structures of macromolecule-ligand complexes through high-resolution powder diffraction analysis and a method for providing suitable microcrystalline powder for diffraction analysis are provided. In one embodiment, powder diffraction data is collected from samples of polycrystalline macromolecule and macromolecule-ligand complex and the refined structure of the macromolecule is used as an approximate model for a combined Rietveld and stereochemical restraint refinement of the macromolecule-ligand complex. A difference Fourier map is calculated and the ligand position and points of interaction between the atoms of the macromolecule and the atoms of the ligand can be deduced and visualized. A suitable polycrystalline sample of macromolecule-ligand complex can be produced by physically agitating a mixture of lyophilized macromolecule, ligand and a solvent.

  7. Dissociation of Multisubunit Protein-Ligand Complexes in the Gas Phase. Evidence for Ligand Migration

    Science.gov (United States)

    Zhang, Yixuan; Deng, Lu; Kitova, Elena N.; Klassen, John S.

    2013-10-01

    The results of collision-induced dissociation (CID) experiments performed on gaseous protonated and deprotonated ions of complexes of cholera toxin B subunit homopentamer (CTB5) with the pentasaccharide (β-D-Gal p-(1→3)-β-D-Gal pNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β-D-Gal p-(1→4)-β-D-Glc p (GM1)) and corresponding glycosphingolipid (β-D-Gal p-(1→3)-β-D-Gal pNAc-(1→4)[α-D-Neu5Ac-(2→3)]-β-D-Gal p-(1→4)-β-D-Glc p-Cer (GM1-Cer)) ligands, and the homotetramer streptavidin (S4) with biotin (B) and 1,2-dipalmitoyl- sn-glycero-3-phosphoethanolamine-N-(biotinyl) (Btl), are reported. The protonated (CTB5 + 5GM1)n+ ions dissociated predominantly by the loss of a single subunit, with the concomitant migration of ligand to another subunit. The simultaneous loss of ligand and subunit was observed as a minor pathway. In contrast, the deprotonated (CTB5 + 5GM1)n- ions dissociated preferentially by the loss of deprotonated ligand; the loss of ligand-bound and ligand-free subunit were minor pathways. The presence of ceramide (Cer) promoted ligand migration and the loss of subunit. The main dissociation pathway for the protonated and deprotonated (S4 + 4B)n+/- ions, as well as for deprotonated (S4 + 4Btl)n- ions, was loss of the ligand. However, subunit loss from the (S4 + 4B)n+ ions was observed as a minor pathway. The (S4 + 4Btl)n+ ions dissociated predominantly by the loss of free and ligand-bound subunit. The charge state of the complex and the collision energy were found to have little effect on the relative contribution of the different dissociation channels. Thermally-driven ligand migration between subunits was captured in the results of molecular dynamics simulations performed on protonated (CTB5 + 5GM1)15+ ions (with a range of charge configurations) at 800 K. Notably, the migration pathway was found to be highly dependent on the charge configuration of the ion. The main conclusion of this study is that the dissociation pathways of multisubunit protein-ligand

  8. The α7 nicotinic acetylcholine receptor ligands methyllycaconitine, NS6740 and GTS-21 reduce lipopolysaccharide-induced TNF-α release from microglia

    DEFF Research Database (Denmark)

    Thomsen, Morten S; Mikkelsen, Jens D

    2012-01-01

    The anti-inflammatory properties of, particularly the α7, nicotinic acetylcholine receptors (nAChRs) in the peripheral immune system are well documented. There are also reports of anti-inflammatory actions of nicotine in the CNS, but it is unclear, whether this is due to activation or inhibition...... of nAChRs. Here we investigate the mechanisms behind α7 nAChR-mediated modulation of TNF-α release. We show that α7 nAChR agonists or positive allosteric modulators do not affect LPS-induced release of the pro-inflammatory cytokine TNF-α from cultured microglia. This suggests that classical activation...... of, i.e. ion-flux through, the α7 nAChR does not reduce TNF-α release from activated microglia. Contrarily, the α7 nAChR antagonist methyllycaconitine and the weak (...

  9. Ligand-Receptor Interactions

    CERN Document Server

    Bongrand, Pierre

    2008-01-01

    The formation and dissociation of specific noncovalent interactions between a variety of macromolecules play a crucial role in the function of biological systems. During the last few years, three main lines of research led to a dramatic improvement of our understanding of these important phenomena. First, combination of genetic engineering and X ray cristallography made available a simultaneous knowledg of the precise structure and affinity of series or related ligand-receptor systems differing by a few well-defined atoms. Second, improvement of computer power and simulation techniques allowed extended exploration of the interaction of realistic macromolecules. Third, simultaneous development of a variety of techniques based on atomic force microscopy, hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or flexible transducers yielded direct experimental information of the behavior of single ligand receptor bonds. At the same time, investigation of well defined cellular models raised the ...

  10. TLR9 ligands induce S100A8 in macrophages via a STAT3-dependent pathway which requires IL-10 and PGE2.

    Directory of Open Access Journals (Sweden)

    Kenneth Hsu

    Full Text Available S100A8 and S100A9 are highly-expressed calcium-binding proteins in neutrophils and monocytes, and in subsets of macrophages in inflammatory lesions. Unmethylated CpG motifs found in bacterial and viral DNA are potent activators of innate immunity via Toll-like receptor 9 (TLR9. S100A8, but not S100A9, mRNA and protein was directly induced by CpG-DNA in murine and human macrophages. Induction in murine macrophages peaked at 16 h. CpG-DNA-induced S100A8 required de novo protein synthesis; IL-10 and Prostaglandin E2 (PGE2 synergistically enhanced expression and promoted earlier gene induction. Inhibitors of endogenous IL-10, PGE2, and the E prostanoid (EP 4 receptor strongly suppressed S100A8 expression, particularly when combined. Thus, S100A8 induction by E. coli DNA required both IL-10 and PGE2/EP4 signaling. The MAPKs, PI3K and JAK pathways were essential, whereas ERK1/2 appeared to play a direct role. S100A8 induction by CpG-DNA was controlled at the transcriptional level. The promoter region responsible for activation, either directly, or indirectly via IL-10 and PGE2, was located within a -178 to -34-bp region and required STAT3 binding. Because of the robust links connecting IL-10 and PGE2 with an anti-inflammatory macrophage phenotype, the induction profile of S100A8 strongly indicates a role for this protein in resolution of inflammation.

  11. TLR9 ligands induce S100A8 in macrophages via a STAT3-dependent pathway which requires IL-10 and PGE2.

    Science.gov (United States)

    Hsu, Kenneth; Chung, Yuen Ming; Endoh, Yasumi; Geczy, Carolyn L

    2014-01-01

    S100A8 and S100A9 are highly-expressed calcium-binding proteins in neutrophils and monocytes, and in subsets of macrophages in inflammatory lesions. Unmethylated CpG motifs found in bacterial and viral DNA are potent activators of innate immunity via Toll-like receptor 9 (TLR9). S100A8, but not S100A9, mRNA and protein was directly induced by CpG-DNA in murine and human macrophages. Induction in murine macrophages peaked at 16 h. CpG-DNA-induced S100A8 required de novo protein synthesis; IL-10 and Prostaglandin E2 (PGE2) synergistically enhanced expression and promoted earlier gene induction. Inhibitors of endogenous IL-10, PGE2, and the E prostanoid (EP) 4 receptor strongly suppressed S100A8 expression, particularly when combined. Thus, S100A8 induction by E. coli DNA required both IL-10 and PGE2/EP4 signaling. The MAPKs, PI3K and JAK pathways were essential, whereas ERK1/2 appeared to play a direct role. S100A8 induction by CpG-DNA was controlled at the transcriptional level. The promoter region responsible for activation, either directly, or indirectly via IL-10 and PGE2, was located within a -178 to -34-bp region and required STAT3 binding. Because of the robust links connecting IL-10 and PGE2 with an anti-inflammatory macrophage phenotype, the induction profile of S100A8 strongly indicates a role for this protein in resolution of inflammation.

  12. Therapeutic androgen receptor ligands

    OpenAIRE

    Allan, George F.; Sui, Zhihua

    2003-01-01

    In the past several years, the concept of tissue-selective nuclear receptor ligands has emerged. This concept has come to fruition with estrogens, with the successful marketing of drugs such as raloxifene. The discovery of raloxifene and other selective estrogen receptor modulators (SERMs) has raised the possibility of generating selective compounds for other pathways, including androgens (that is, selective androgen receptor modulators, or SARMs).

  13. Imidazoline receptors ligands

    Directory of Open Access Journals (Sweden)

    Agbaba Danica

    2012-01-01

    Full Text Available Extensive biochemical and pharmacological studies have determined three different subtypes of imidazoline receptors: I1-imidazoline receptors (I1-IR involved in central inhibition of sympathicus that produce hypotensive effect; I2-imidazoline receptors (I2-IR modulate monoamine oxidase B activity (MAO-B; I3-imidazoline receptors (I3-IR regulate insulin secretion from pancreatic β-cells. Therefore, the I1/I2/I3 imidazoline receptors are selected as new, interesting targets for drug design and discovery. Novel selective I1/I2/I3 agonists and antagonists have been recently developed. In the present review, we provide a brief update to the field of imidazoline research, highlighting some of the chemical diversity and progress made in the 2D-QSAR, 3D-QSAR and quantitative pharmacophore development studies of I1-IR and I2-IR imidazoline receptor ligands. Theoretical studies of I3-IR ligands are not yet performed because of insufficient number of synthesized I3-IR ligands.

  14. Expanding dendritic cells in vivo enhances the induction of oral tolerance.

    Science.gov (United States)

    Viney, J L; Mowat, A M; O'Malley, J M; Williamson, E; Fanger, N A

    1998-06-15

    The intestine is under perpetual challenge from both pathogens and essential nutrients, yet the mucosal immune system is able to discriminate effectively between harmful and innocuous Ags. It is likely that this selective immunoregulation is dependent on the nature of the APC at sites where gut Ags are processed and presented. Dendritic cells (DC) are considered the most potent of APC and are renowned for their immunostimulatory role in the initiation of immune responses. To investigate the role of DC in regulating the homeostatic balance between mucosal immunity and tolerance, we treated mice with Flt3 ligand (Flt3L), a growth factor that expands DC in vivo, and assessed subsequent systemic immune responsiveness using mouse models of oral tolerance. Surprisingly, mice treated with Flt3L to expand DC exhibited more profound systemic tolerance after they were fed soluble Ag. Most notably, tolerance could be induced in Flt3L-treated mice using very low doses of Ag that were ineffective in control animals. These findings contrast with the generally accepted view of DC as immunostimulatory APC and furthermore suggest a pivotal role for DC during the induction of tolerance following mucosal administration of Ag.

  15. Ligand binding induces a sharp decrease in hydrophobicity of folate binding protein assessed by 1-anilinonaphthalene-8-sulphonate which suppresses self-association of the hydrophobic apo-protein.

    Science.gov (United States)

    Holm, Jan; Lawaetz, Anders J; Hansen, Steen I

    2012-08-17

    High affinity folate binding protein (FBP) regulates as a soluble protein and as a cellular receptor intracellular trafficking of folic acid, a vitamin of great importance to cell growth and division. We addressed two issues of potential importance to the biological function of FBP, a possible decrease of the surface hydrophobicity associated with the ligand-induced conformation change of FBP, and protein-inter-protein interactions involved in self-association of hydrophobic apo-FBP. The extrinsic fluorescent apolar dye 1-anilinonaphthalene-8-sulphonate (ANS) exhibited enhanced fluorescence intensity and a blueshift of emission maximum from 510-520 nm to 460-470 nm upon addition of apo-FBP indicating binding to a strongly hydrophobic environment. Neither enhancement of fluorescence nor blueshift of ANS emission maximum occurred when folate-ligated holo-FBP replaced apo-FBP. The drastic decrease in surface hydrophobicity of holo-FBP could have bearings on the biological function of FBP since changes in surface hydrophobicity have critical effects on the biological function of receptors and transport proteins. ANS interacts with exposed hydrophobic surfaces on proteins and may thereby block and prevent aggregation of proteins (chaperone-like effect). Hence, hydrophobic interactions seemed to participate in the concentration-dependent self-association of apo-FBP which was suppressed by high ANS concentrations in light scatter measurements.

  16. Neuronal and glial cell type-specific promoters within adenovirus recombinants restrict the expression of the apoptosis-inducing molecule Fas ligand to predetermined brain cell types, and abolish peripheral liver toxicity.

    Science.gov (United States)

    Morelli, A E; Larregina, A T; Smith-Arica, J; Dewey, R A; Southgate, T D; Ambar, B; Fontana, A; Castro, M G; Lowenstein, P R

    1999-03-01

    Gene therapy using Fas ligand (FasL) for treatment of tumours and protection of transplant rejection is hampered because of the systemic toxicity of FasL. In the present study, recombinant replication-defective adenovirus vectors (RAds) encoding FasL under the control of either the neuronal-specific neuronal-specific enolase (NSE) promoter or the astrocyte-specific glial fibrillary acidic protein (GFAP) promoter have been constructed. The cell type-specific expression of FasL in both neurons and glial cells in primary cultures, and in neuronal and glial cell lines is demonstrated. Furthermore, transgene expression driven by the neuronal and glial promoter was not detected in fibroblastic or epithelial cell lines. Expression of FasL driven by a major immediate early human cytomegalovirus promoter (MIEhCMV) was, however, achieved in all cells tested. As a final test of the stringency of transgene-specific expression, the RAds were injected directly into the bloodstream of mice. The RAds encoding FasL under the control of the non-cell type-specific MIEhCMV promoter induced acute generalized liver haemorrhage with hepatocyte apoptosis, while the RAds containing the NSE or GFAP promoter sequences were completely non-toxic. This demonstrates the specificity of transgene expression, enhanced safety during systemic administration, and tightly regulated control of transgene expression of highly cytotoxic gene products, encoded within transcriptionally targeted RAds.

  17. Antioxidant alpha-lipoic acid inhibits osteoclast differentiation by reducing nuclear factor-kappaB DNA binding and prevents in vivo bone resorption induced by receptor activator of nuclear factor-kappaB ligand and tumor necrosis factor-alpha.

    Science.gov (United States)

    Kim, Hyon Jong; Chang, Eun-Ju; Kim, Hyun-Man; Lee, Seung Bok; Kim, Hyun-Duck; Su Kim, Ghi; Kim, Hong-Hee

    2006-05-01

    The relationship between oxidative stress and bone mineral density or osteoporosis has recently been reported. As bone loss occurring in osteoporosis and inflammatory diseases is primarily due to increases in osteoclast number, reactive oxygen species (ROS) may be relevant to osteoclast differentiation, which requires receptor activator of nuclear factor-kappaB ligand (RANKL). Tumor necrosis factor-alpha (TNF-alpha) frequently present in inflammatory conditions has a profound synergy with RANKL in osteoclastogenesis. In this study, we investigated the effects of alpha-lipoic acid (alpha-LA), a strong antioxidant clinically used for some time, on osteoclast differentiation and bone resorption. At concentrations showing no growth inhibition, alpha-LA potently suppressed osteoclastogenesis from bone marrow-derived precursor cells driven either by a high-dose RANKL alone or by a low-dose RANKL plus TNF-alpha (RANKL/TNF-alpha). alpha-LA abolished ROS elevation by RANKL or RANKL/TNF-alpha and inhibited NF-kappaB activation in osteoclast precursor cells. Specifically, alpha-LA reduced DNA binding of NF-kappaB but did not inhibit IKK activation. Furthermore, alpha-LA greatly suppressed in vivo bone loss induced by RANKL or TNF-alpha in a calvarial remodeling model. Therefore, our data provide evidence that ROS plays an important role in osteoclast differentiation through NF-kappaB regulation and the antioxidant alpha-lipoic acid has a therapeutic potential for bone erosive diseases.

  18. Coexistence of two thermally induced intramolecular electron transfer processes in a series of metal complexes [M(Cat-N-BQ)(Cat-N-SQ)]/[M(Cat-N-BQ)2] (M = Co, Fe, and Ni) bearing non-innocent catechol-based ligands: a combined experimental and theoretical study.

    Science.gov (United States)

    Evangelio, Emi; Bonnet, Marie-Laure; Cabañas, Miquel; Nakano, Motohiro; Sutter, Jean-Pascal; Dei, Andrea; Robert, Vincent; Ruiz-Molina, Daniel

    2010-06-11

    The different thermally induced intermolecular electron transfer (IET) processes that can take place in the series of complexes [M(Cat-N-BQ)(Cat-N-SQ)]/[M(Cat-N-BQ)(2)], for which M = Co (2), Fe (3) and Ni(4), and Cat-N-BQ and Cat-N-SQ denote the mononegative (Cat-N-BQ(-)) or dinegative (Cat-N-SQ(2-)) radical forms of the tridentate Schiff-base ligand 3,5-di-tert-butyl-1,2-quinone-1-(2-hydroxy-3,5-di-tert-butylphenyl)imine, have been studied by variable-temperature UV/Vis and NMR spectroscopies. Depending on the metal ion, rather different behaviors are observed. Complex 2 has been found to be one of the few examples so far reported to exhibit the coexistence of two thermally induced electron transfer processes, ligand-to-metal (IET(LM)) and ligand-to-ligand (IET(LL)). IET(LL) was only found to take place in complex 3, and no IET was observed for complex 4. Such experimental studies have been combined with ab initio wavefunction-based CASSCF/CASPT2 calculations. Such a strategy allows one to solicit selectively the speculated orbitals and to access the ground states and excited-spin states, as well as charge-transfer states giving additional information on the different IET processes.

  19. Evaluation of preventive and therapeutic activity of novel non-steroidal anti-inflammatory drug, CG100649, in colon cancer: Increased expression of TNF-related apoptosis-inducing ligand receptors enhance the apoptotic response to combination treatment with TRAIL.

    Science.gov (United States)

    Woo, Jong Kyu; Kang, Ju-Hee; Jang, Yeong-Su; Ro, Seonggu; Cho, Joong Myung; Kim, Hwan-Mook; Lee, Sang-Jin; Oh, Seung Hyun

    2015-04-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) have been suggested as the potential new class of preventive or therapeutic antitumor agents. The aim of the present study was to evaluate the antitumor activity of the novel NSAID, CG100649. CG100649 is a novel NSAID dual inhibitor for COX-2 and carbonic anhydrase (CA)-I/-II. In the present study, we investigated the alternative mechanism by which CG100649 mediated suppression of the colon cancer growth and development. The anchorage‑dependent and -independent clonogenic assay showed that CG100649 inhibited the clonogenicity of human colon cancer cells. The flow cytometric analysis showed that CG100649 induced the G2/M cell cycle arrest in colon cancer cells. Animal studies showed that CG100649 inhibited the tumor growth in colon cancer xenograft in nude mice. Furthermore, quantitative PCR and FACS analysis demonstrated that CG100649 upregulated the expression of TNF-related apoptosis-inducing ligand (TRAIL) receptors (DR4 and DR5) but decreased the expression of decoy receptors (DcR1 and DcR2) in colon cancer cells. The results showed that CG100649 treatment sensitized TRAIL‑mediated growth suppression and apoptotic cell death. The combination treatment resulted in significant repression of the intestinal polyp formation in APCmin/+ mice. Our data clearly demonstrated that CG100649 contains preventive and therapeutic activity for colon cancer. The present study may be useful for identification of the potential benefit of the NSAID CG100649, for the achievement of a better treatment response in colon cancer.

  20. Two novel α7 nicotinic acetylcholine receptor ligands: in vitro properties and their efficacy in collagen-induced arthritis in mice.

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