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Sample records for cell death suppressor

  1. Myeloid-derived suppressor activity is mediated by monocytic lineages maintained by continuous inhibition of extrinsic and intrinsic death pathways.

    Science.gov (United States)

    Haverkamp, Jessica M; Smith, Amber M; Weinlich, Ricardo; Dillon, Christopher P; Qualls, Joseph E; Neale, Geoffrey; Koss, Brian; Kim, Young; Bronte, Vincenzo; Herold, Marco J; Green, Douglas R; Opferman, Joseph T; Murray, Peter J

    2014-12-18

    Nonresolving inflammation expands a heterogeneous population of myeloid suppressor cells capable of inhibiting T cell function. This heterogeneity has confounded the functional dissection of individual myeloid subpopulations and presents an obstacle for antitumor immunity and immunotherapy. Using genetic manipulation of cell death pathways, we found the monocytic suppressor-cell subset, but not the granulocytic subset, requires continuous c-FLIP expression to prevent caspase-8-dependent, RIPK3-independent cell death. Development of the granulocyte subset requires MCL-1-mediated control of the intrinsic mitochondrial death pathway. Monocytic suppressors tolerate the absence of MCL-1 provided cytokines increase expression of the MCL-1-related protein A1. Monocytic suppressors mediate T cell suppression, whereas their granulocytic counterparts lack suppressive function. The loss of the granulocytic subset via conditional MCL-1 deletion did not alter tumor incidence implicating the monocytic compartment as the functionally immunosuppressive subset in vivo. Thus, death pathway modulation defines the development, survival, and function of myeloid suppressor cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Suppressor cells in transplantation tolerance II. Maturation of suppressor cells in the bone marrow chimera

    International Nuclear Information System (INIS)

    Tutschka, P.J.; Ki, P.F.; Beschorner, W.E.; Hess, A.D.; Santos, G.W.

    1981-01-01

    Histoincompatible bone marrow allografts were established in lethally irradiated rats. At various times after transplantation, the spleen cells were harvested, subjected to mixed lymphocyte cultures, and assayed for suppressor cells in vitro and in vivo by adoptive transfer studies. Alloantigen-nonspecific suppressor cells appeared in the chimera at 40 days after grafting, coinciding with the resolution of graft-versus-host disease (GVHD). At 250 days the nonspecific suppressor cells were replaced by suppressor cells specifically suppressing donor-versus-host alloantigen responses. At 720 days suppressor cells could no longer be identified by in vitro methods but were identified by in vivo adoptive transfer of transplantation tolerance. After injection of host-type antigen into chimeras, the suppressor cells could be again demonstrated by in vitro methods

  3. Suppressor cells in transplantation tolerance. II. maturation of suppressor cells in the bone marrow chimera

    International Nuclear Information System (INIS)

    Tutschka, P.J.; Ki, P.F.; Beschorner, W.E.; Hess, A.D.; Santos, G.W.

    1981-01-01

    Histoincompatible bone marrow allografts were established in lethally irradiated rats. At various times after transplantation, the spleen cells were harvested, subjected to mixed lymphocyte cultures, and assayed for suppressor cells in vitro and in vivo by adoptive transfer studies. Alloantigen-nonspecific suppressor cells appeared in the chimera at 40 days after grafting, coinciding with the resolution of graft-versus-host disease (GVHD). At 250 days the nonspecific suppressor cells were replaced by suppressor cells specifically suppressing donor-versus-host alloantigen responses. At 720 days suppressor cells could no longer be identified by in vitro methods but were identified by in vivo adoptive transfer of transplantation tolerance. After injection of host-type antigen into chimeras, the suppressor cells could be again demonstrated by in vitro methods

  4. Cdh11 Acts as a Tumor Suppressor in a Murine Retinoblastoma Model by Facilitating Tumor Cell Death

    Science.gov (United States)

    Marchong, Mellone N.; Yurkowski, Christine; Ma, Clement; Spencer, Clarellen; Pajovic, Sanja; Gallie, Brenda L.

    2010-01-01

    CDH11 gene copy number and expression are frequently lost in human retinoblastomas and in retinoblastomas arising in TAg-RB mice. To determine the effect of Cdh11 loss in tumorigenesis, we crossed Cdh11 null mice with TAg-RB mice. Loss of Cdh11 had no gross morphological effect on the developing retina of Cdh11 knockout mice, but led to larger retinal volumes in mice crossed with TAg-RB mice (p = 0.01). Mice null for Cdh11 presented with fewer TAg-positive cells at postnatal day 8 (PND8) (p = 0.01) and had fewer multifocal tumors at PND28 (p = 0.016), compared to mice with normal Cdh11 alleles. However, tumor growth was faster in Cdh11-null mice between PND8 and PND84 (p = 0.003). In tumors of Cdh11-null mice, cell death was decreased 5- to 10-fold (p<0.03 for all markers), while proliferation in vivo remained unaffected (p = 0.121). Activated caspase-3 was significantly decreased and β-catenin expression increased in Cdh11 knockdown experiments in vitro. These data suggest that Cdh11 displays tumor suppressor properties in vivo and in vitro in murine retinoblastoma through promotion of cell death. PMID:20421947

  5. Cdh11 acts as a tumor suppressor in a murine retinoblastoma model by facilitating tumor cell death.

    Directory of Open Access Journals (Sweden)

    Mellone N Marchong

    2010-04-01

    Full Text Available CDH11 gene copy number and expression are frequently lost in human retinoblastomas and in retinoblastomas arising in TAg-RB mice. To determine the effect of Cdh11 loss in tumorigenesis, we crossed Cdh11 null mice with TAg-RB mice. Loss of Cdh11 had no gross morphological effect on the developing retina of Cdh11 knockout mice, but led to larger retinal volumes in mice crossed with TAg-RB mice (p = 0.01. Mice null for Cdh11 presented with fewer TAg-positive cells at postnatal day 8 (PND8 (p = 0.01 and had fewer multifocal tumors at PND28 (p = 0.016, compared to mice with normal Cdh11 alleles. However, tumor growth was faster in Cdh11-null mice between PND8 and PND84 (p = 0.003. In tumors of Cdh11-null mice, cell death was decreased 5- to 10-fold (p<0.03 for all markers, while proliferation in vivo remained unaffected (p = 0.121. Activated caspase-3 was significantly decreased and beta-catenin expression increased in Cdh11 knockdown experiments in vitro. These data suggest that Cdh11 displays tumor suppressor properties in vivo and in vitro in murine retinoblastoma through promotion of cell death.

  6. Non-Canonical Cell Death Induced by p53

    Directory of Open Access Journals (Sweden)

    Atul Ranjan

    2016-12-01

    Full Text Available Programmed cell death is a vital biological process for multicellular organisms to maintain cellular homeostasis, which is regulated in a complex manner. Over the past several years, apart from apoptosis, which is the principal mechanism of caspase-dependent cell death, research on non-apoptotic forms of programmed cell death has gained momentum. p53 is a well characterized tumor suppressor that controls cell proliferation and apoptosis and has also been linked to non-apoptotic, non-canonical cell death mechanisms. p53 impacts these non-canonical forms of cell death through transcriptional regulation of its downstream targets, as well as direct interactions with key players involved in these mechanisms, in a cell type- or tissue context-dependent manner. In this review article, we summarize and discuss the involvement of p53 in several non-canonical modes of cell death, including caspase-independent apoptosis (CIA, ferroptosis, necroptosis, autophagic cell death, mitotic catastrophe, paraptosis, and pyroptosis, as well as its role in efferocytosis which is the process of clearing dead or dying cells.

  7. Induction of suppressor cells in vitro by Candida albicans.

    Science.gov (United States)

    Cuff, C F; Rogers, C M; Lamb, B J; Rogers, T J

    1986-06-01

    Normal splenocytes cultured with Formalin-killed Candida albicans were shown to acquire significant suppressor cell activity in a period of 3 days. These cells were found to suppress both the phytohemagglutinin-induced mitogen response as well as the anti-sheep erythrocyte antibody response. Experiments were carried out to determine the nature of the suppressor cell population. Results showed that these cells were not susceptible to treatment with anti-Thy 1 antibody and complement. Panning experiments showed that the suppressor cells were not plastic-adherent or Mac-1 antigen-positive. The suppressor cells were, however, adherent to anti-mouse immunoglobulin (F(ab')2-fragment)-coated dishes. Additional experiments showed that the suppressor cell activity was susceptible to treatment with monoclonal anti-Lyb 2.1 antibody and complement. These results suggest that the suppressor cell induced in vitro by Candida is a member of the B-lymphocyte lineage.

  8. Modulation of immune response by alloactivated suppressor T cells

    International Nuclear Information System (INIS)

    Bernstein, A.; Sopori, M.L.; Gose, J.E.; Sondel, P.M.

    1979-01-01

    These studies show that there may be several different kinds of suppressor cells, each activated by different pathways and able to suppress different parts of the immune response either specifically or nonspecifically. As such, the physiology of one type of suppressor cell need not necessarily apply to that of another type of suppressor. Thus we emphasize the trap that the suppressor cell option provides: that is, virtually any previously inexplicable in vitro and in vivo immune phenomenon can always be adequately accounted for by evoking a suppressor mechanism, either by suppressing the response or suppressing the suppressor

  9. The von Hippel-Lindau tumor suppressor regulates programmed cell death 5-mediated degradation of Mdm2

    NARCIS (Netherlands)

    Essers, P B; Klasson, T D; Pereboom, T C; Mans, D A; Nicastro, M; Boldt, K; Giles, R H; MacInnes, A W

    2015-01-01

    Functional loss of the von Hippel-Lindau (VHL) tumor suppressor protein (pVHL), which is part of an E3-ubiquitin ligase complex, initiates most inherited and sporadic clear-cell renal cell carcinomas (ccRCC). Genetic inactivation of the TP53 gene in ccRCC is rare, suggesting that an alternate

  10. Induction of specific suppressor T cells in vitro

    International Nuclear Information System (INIS)

    Eardley, D.D.; Gershon, R.K.

    1976-01-01

    We describe conditions for generating sheep red blood cell-specific suppressor T cells in Mishell-Dutton cultures. The production of specific suppressor cells is favored by increasing antigen dose in the initial culture but can be produced by transferring more cells when lower doses of antigen are used. Transfer of small numbers of cells cultured with low doses of antigen leads to a specific helper effect. Transfer of large numbers of educated cells leads to nonspecific suppression. Suppression can be effected by the effluent cells from nylon wool columns which do not make detectable PFC. A fraction of these cells become resistant to treatment with anti-T cell sera and complement after culture. The suppressor cells are radiation sensitive and must be able to synthesize protein to suppress. They take 2 to 3 days of education to reach maximum suppressive efficiency and will not suppress cultures if added 2 to 3 days after culture initiation. Their production is favored by the absence of mercaptoethanol, suggesting that the observed suppression is not ''too much help.'' The ability to generate specific suppressor cells in vitro should be of great benefit in determining the factors that regulate their appearance in vivo

  11. Soluble suppressor supernatants elaborated by concanavalin A-activated human mononuclear cells. Characterization of a soluble suppressor of B cell immunoglobulin production

    International Nuclear Information System (INIS)

    Fleisher, T.A.; Greene, W.C.; Blaese, R.M.; Waldmann, T.A.

    1981-01-01

    Human peripheral blood mononuclear cells (PBMC) activated with the mitogenic lectin concanavalin A (Con A) elaborate a soluble immune suppressor supernatant (SISS) that contains at least 2 distinct suppressor factors. One of these, SISS-B, inhibits polyclonal B cell immunoglobulin production, whereas the other, SISS-T, suppresses T cell proliferation to both mitogens and antigens. The latter mediator is discussed in the companion paper. Characteristics of the human soluble suppressor of B cell immunoglobulin production (SISS-B) include: 1) inhibition by a noncytotoxic mechanism, 2) loss of activity in the presence of the monosaccharide L-rhamnose, 3) appearance within 8 to 16 hr after the addition of Con A, 4) elaboration by cells irradiated with 500 or 2000 rads, 5) production by highly purified T cells, 6) stability at pH 2.5 but instability at 56/sup o/C, and 7) m.w. of 60 to 80,000. These data indicate that after Con A activation, selected T cells not only become potent suppressor cells, but also generate a soluble saccharide-specific factor(s) that inhibits polyclonal immunoglobulin production by human B cells

  12. Cylindromatosis mediates neuronal cell death in vitro and in vivo.

    Science.gov (United States)

    Ganjam, Goutham K; Terpolilli, Nicole Angela; Diemert, Sebastian; Eisenbach, Ina; Hoffmann, Lena; Reuther, Christina; Herden, Christiane; Roth, Joachim; Plesnila, Nikolaus; Culmsee, Carsten

    2018-01-19

    The tumor-suppressor cylindromatosis (CYLD) is a deubiquitinating enzyme and key regulator of cell proliferation and inflammation. A genome-wide siRNA screen linked CYLD to receptor interacting protein-1 (RIP1) kinase-mediated necroptosis; however, the exact mechanisms of CYLD-mediated cell death remain unknown. Therefore, we investigated the precise role of CYLD in models of neuronal cell death in vitro and evaluated whether CYLD deletion affects brain injury in vivo. In vitro, downregulation of CYLD increased RIP1 ubiquitination, prevented RIP1/RIP3 complex formation, and protected neuronal cells from oxidative death. Similar protective effects were achieved by siRNA silencing of RIP1 or RIP3 or by pharmacological inhibition of RIP1 with necrostatin-1. In vivo, CYLD knockout mice were protected from trauma-induced brain damage compared to wild-type littermate controls. These findings unravel the mechanisms of CYLD-mediated cell death signaling in damaged neurons in vitro and suggest a cell death-mediating role of CYLD in vivo.

  13. Lazarus1, a DUF300 Protein, Contributes to Programmed Cell Death Associated with Arabidopsis acd11 and the Hypersensitive Response

    DEFF Research Database (Denmark)

    Malinovsky, F.G.; Brodersen, P.; Fiil, B.K.

    2010-01-01

    ) mutant exhibits HR-like accelerated cell death, and cell death execution in acd11 shares genetic requirements for HR execution triggered by one subclass of R proteins. Methodology/Principal Findings: To identify genes required for this PCD pathway, we conducted a genetic screen for suppressors of acd11......Background: Programmed cell death (PCD) is a necessary part of the life of multi-cellular organisms. A type of plant PCD is the defensive hypersensitive response (HR) elicited via recognition of a pathogen by host resistance (R) proteins. The lethal, recessive accelerated cell death 11 (acd11......, here called lazarus (laz) mutants. In addition to known suppressors of R protein-mediated HR, we isolated 13 novel complementation groups of dominant and recessive laz mutants. Here we describe laz1, which encodes a protein with a domain of unknown function (DUF300), and demonstrate that LAZ1...

  14. Off and back-on again: a tumor suppressor's tale.

    Science.gov (United States)

    Acosta, Jonuelle; Wang, Walter; Feldser, David M

    2018-06-01

    Tumor suppressor genes play critical roles orchestrating anti-cancer programs that are both context dependent and mechanistically diverse. Beyond canonical tumor suppressive programs that control cell division, cell death, and genome stability, unexpected tumor suppressor gene activities that regulate metabolism, immune surveillance, the epigenetic landscape, and others have recently emerged. This diversity underscores the important roles these genes play in maintaining cellular homeostasis to suppress cancer initiation and progression, but also highlights a tremendous challenge in discerning precise context-specific programs of tumor suppression controlled by a given tumor suppressor. Fortunately, the rapid sophistication of genetically engineered mouse models of cancer has begun to shed light on these context-dependent tumor suppressor activities. By using techniques that not only toggle "off" tumor suppressor genes in nascent tumors, but also facilitate the timely restoration of gene function "back-on again" in disease specific contexts, precise mechanisms of tumor suppression can be revealed in an unbiased manner. This review discusses the development and implementation of genetic systems designed to toggle tumor suppressor genes off and back-on again and their potential to uncover the tumor suppressor's tale.

  15. Regulatory role for the memory B cell as suppressor-inducer of feedback control

    International Nuclear Information System (INIS)

    Kennedy, M.W.; Thomas, D.B.

    1983-01-01

    A regulatory role is proposed for the antigen-responsive B cell, as suppressor-inducer of feedback control during the secondary response in vivo. In a double adoptive transfer of memory cells primed to a thymus-dependent antigen from one irradiated host to another, antigen-specific suppressors are generated after a critical time in the primary recipient, able to entirely ablate a secondary anti-hapten response. Positive cell selection in the fluorescence-activated cell sorter confirmed that suppression was mediated by an Lyt-2+ T cell; however, positively selected B cells were also inhibitory and able to induce suppressors in a carrier-specific manner: B hapten induced suppressors in a carrier-primed population, and B carrier induced suppressors in a hapten-carrier population. At the peak of the antibody response in the primary host, memory B cells and their progeny were unable to differentiate further to plasma cells due to their intrinsic suppressor-inducer activity, but this autoregulatory circuit could be severed by adoptive transfer to carrier-primed, X-irradiated recipients

  16. Human cord blood suppressor T lymphocytes. II. Characterization of inducer of suppressor cells

    International Nuclear Information System (INIS)

    Cheng, H.; Delespesse, G.

    1986-01-01

    Previously, we reported an antigen nonspecific inducer of T suppressor cell factor (TisF) produced by cord blood mononuclear cells (MNC) in 48-hr, two-way mixed lymphocyte cultures (MLC). The target of this factor was a radiosensitive, T4+ (T8-) adult suppressor T cell subset. The cellular origin of this TisF was examined in the present study. IgG production by pokeweed mitogen (PWM)-stimulated adult MNC was used as an assay for TisF activity. It was found that TisF-producing cells formed rosettes with sheep erythrocytes (E+) and were independent of adherent cells (AC) in the production of TisF. They were resistant to irradiation (2500 rads) and phenotypic characterization with T cell reactive monoclonal antibodies indicated that they resided in the T8- (T4+) population. Furthermore, both TQ1- and TQ1+ cells were required for the production of TisF activity and such activity could not be reconstituted by supernatants from TQ1- MLC and TQ1+ MLC. These results indicate that the production of TisF is dependent upon interactions between radioresistant E+, T8-, TQ1- and radioresistant E+, T8-, TQ1+ cells

  17. No evidence that genetic variation in the myeloid-derived suppressor cell pathway influences ovarian cancer survival

    DEFF Research Database (Denmark)

    Sucheston-Campbell, Lara E; Cannioto, Rikki; Clay, Alyssa I

    2017-01-01

    BACKGROUND: The precise mechanism by which the immune system is adversely affected in cancer patients remains poorly understood, but the accumulation of immune suppressive/pro-tumorigenic myeloid-derived suppressor cells (MDSCs) is thought to be one prominent mechanism contributing to immunologic...... tolerance of malignant cells in epithelial ovarian cancer (EOC). To this end, we hypothesized genetic variation in MDSC pathway genes would be associated with survival after EOC diagnoses. METHODS: We measured the hazard of death due to EOC within 10 years of diagnosis, overall and by invasive subtype...

  18. Programmed cell death 4 (PDCD4) is an important functional target of the microRNA miR-21 in breast cancer cells

    DEFF Research Database (Denmark)

    Frankel, Lisa; Christoffersen, Nanna R; Jacobsen, Anders

    2008-01-01

    growth. Using array expression analysis of MCF-7 cells depleted of miR-21, we have identified mRNA targets of mir-21 and have shown a link between miR-21 and the p53 tumor suppressor protein. We furthermore found that the tumor suppressor protein Programmed Cell Death 4 (PDCD4) is regulated by miR-21......MicroRNAs are emerging as important regulators of cancer-related processes. The miR-21 microRNA is overexpressed in a wide variety of cancers and has been causally linked to cellular proliferation, apoptosis, and migration. Inhibition of mir-21 in MCF-7 breast cancer cells causes reduced cell...... and demonstrated that PDCD4 is a functionally important target for miR-21 in breast cancer cells....

  19. Concanavalin A-induced and spontaneous suppressor cell activities in peripheral blood lymphocytes and spleen cells from gastric cancer patients.

    Science.gov (United States)

    Toge, T; Hamamoto, S; Itagaki, E; Yajima, K; Tanada, M; Nakane, H; Kohno, H; Nakanishi, K; Hattori, T

    1983-11-01

    In 173 gastric cancer patients, activities of Concanavalin-A-induced suppressor cells (Con-AS) and spontaneous suppressor cells (SpS) in peripheral blood lymphocytes (PBL), splenic vein lymphocytes (SVL), and spleen cells (SCs) were investigated. Suppressions by Con-AS in PBL were significantly effective in patients of Stages III and IV, while suppressions by SpS were effective in patients with recurrent tumors. Thus, in PBLs of cancer patients, suppressor precursors, which are considered to be activated in vitro by Concanavalin-A, seemed to appear with the advances of the disease, and SpS activities, which could be already activated in vivo, seemed to increase in the terminal stage. In SCs, increased activities of Con-AS, but normal activities of SpS, were observed, and these suppressor-cell populations consisted of glass nonadherent cells. Suppressor activities of SCs would be due to suppressor T-cells, not to other types of cells. Furthermore, Con-AS existed in the medium-sized lymphocytes, which were fractionated on the basis of cell size, while SpS in the large-sized lymphocytes. A higher proportion of T-cells, bearing Fc receptors for IgG, was observed in the larger-sized lymphocyte fractions. Cell numbers in the large-sized lymphocyte fraction tended to increase with the advances of tumors. From these results, it is suggested that higher presence of suppressor precursors and the increase of SpS activities may occur in cancer patients, depending on the tumor advancing.

  20. Nonspecific suppressor T cells cause decreased mixed lymphocyte culture reactivity in bone marrow transplant patients

    International Nuclear Information System (INIS)

    Harada, M.; Ueda, M.; Nakao, S.; Kondo, K.; Odaka, K.; Shiobara, S.; Matsue, K.; Mori, T.; Matsuda, T.

    1986-01-01

    Decreased reactivity in mixed lymphocyte culture (MLC) was observed in patients within 1 yr after allogeneic and autologous bone marrow transplantation. Suppressor activity of peripheral blood mononuclear cells (PBMC) from transplant patients was studied by adding these cells as modulator cells to a bidirectional MLC with cells from normal individuals. PBMC from transplant patients markedly suppressed MLC reactivity in a dose-dependent manner. Suppressor activity was present in cells forming rosettes with sheep erythrocytes. Treatment of modulator cells with monoclonal antibodies against T cell differentiation antigens (OKT8, OKIa1) and complement completely abolished suppression of MLC. Suppressor activity was unaffected by 30 Gy irradiation. Suppressor activity declined gradually after transplantation and was inversely correlated with MLC reactivity of each patient at a significant level (p less than 0.01). These observations suggest that OKT8+ Ia+ radioresistant suppressor T cells play a role in the development of decreased MLC reactivity observed during the early post-transplant period

  1. History of myeloid-derived suppressor cells.

    Science.gov (United States)

    Talmadge, James E; Gabrilovich, Dmitry I

    2013-10-01

    Tumour-induced granulocytic hyperplasia is associated with tumour vasculogenesis and escape from immunity via T cell suppression. Initially, these myeloid cells were identified as granulocytes or monocytes; however, recent studies have revealed that this hyperplasia is associated with populations of multipotent progenitor cells that have been identified as myeloid-derived suppressor cells (MDSCs). The study of MDSCs has provided a wealth of information regarding tumour pathobiology, has extended our understanding of neoplastic progression and has modified our approaches to immune adjuvant therapy. In this Timeline article, we discuss the history of MDSCs, their influence on tumour progression and metastasis, and the crosstalk between tumour cells, MDSCs and the host macroenvironment.

  2. Untangling the Roles of Anti-Apoptosis in Regulating Programmed Cell Death using Humanized Yeast Cells

    International Nuclear Information System (INIS)

    Clapp, Caitlin; Portt, Liam; Khoury, Chamel; Sheibani, Sara; Eid, Rawan; Greenwood, Matthew; Vali, Hojatollah; Mandato, Craig A.; Greenwood, Michael T.

    2012-01-01

    Genetically programmed cell death (PCD) mechanisms, including apoptosis, are important for the survival of metazoans since it allows, among things, the removal of damaged cells that interfere with normal function. Cell death due to PCD is observed in normal processes such as aging and in a number of pathophysiologies including hypoxia (common causes of heart attacks and strokes) and subsequent tissue reperfusion. Conversely, the loss of normal apoptotic responses is associated with the development of tumors. So far, limited success in preventing unwanted PCD has been reported with current therapeutic approaches despite the fact that inhibitors of key apoptotic inducers such as caspases have been developed. Alternative approaches have focused on mimicking anti-apoptotic processes observed in cells displaying increased resistance to apoptotic stimuli. Hormesis and pre-conditioning are commonly observed cellular strategies where sub-lethal levels of pro-apoptotic stimuli lead to increased resistance to higher or lethal levels of stress. Increased expression of anti-apoptotic sequences is a common mechanism mediating these protective effects. The relevance of the latter observation is exemplified by the observation that transgenic mice overexpressing anti-apoptotic genes show significant reductions in tissue damage following ischemia. Thus strategies aimed at increasing the levels of anti-apoptotic proteins, using gene therapy or cell penetrating recombinant proteins are being evaluated as novel therapeutics to decrease cell death following acute periods of cell death inducing stress. In spite of its functional and therapeutic importance, more is known regarding the processes involved in apoptosis than anti-apoptosis. The genetically tractable yeast Saccharomyces cerevisiae has emerged as an exceptional model to study multiple aspects of PCD including the mitochondrial mediated apoptosis observed in metazoans. To increase our knowledge of the process of anti

  3. Suppressor cells in transplantation tolerance. III. The role of antigen in the maintenance of transplantation tolerance

    International Nuclear Information System (INIS)

    Tutschka, P.J.; Hess, A.D.; Beschorner, W.E.; Santos, G.W.

    1982-01-01

    Suppressor cells, which in an alloantigen-specific manner inhibit proliferation of donor cells to host antigens in a mixed lymphocyte culture and adoptively transfer the suppression of graft-versus-host disease (GVHD), undergo a gradual clonal reduction in long-term, allogeneic, histoincompatible rat radiation chimeras until they can no longer be measured in an in vitro suppressor cell assay. When lymphohematopoietic cells from these chimeras are transferred into lethally irradiated secondary recipients of original donor strain, the suppressor cells, now in a target antigen-free environment, undergo a further clonal reduction. After parking for 120 days, the chimeric cells are specifically tolerant to original host antigens, but cannot adoptively transfer suppression of GVHD. When chimeric cells, parked for 120 days in secondary recipients of original donor strain, are stimulated with original host-type antigen repeatedly during or once at the end of the parking period, the suppressor cell clone is expanded, suppressor cells can be identified in vitro, and suppression of GVHD can adoptively be transferred to tertiary recipients

  4. Gene trapping identifies a putative tumor suppressor and a new inducer of cell migration

    International Nuclear Information System (INIS)

    Guardiola-Serrano, Francisca; Haendeler, Judith; Lukosz, Margarete; Sturm, Karsten; Melchner, Harald von; Altschmied, Joachim

    2008-01-01

    Tumor necrosis factor alpha (TNFα) is a pleiotropic cytokine involved in apoptotic cell death, cellular proliferation, differentiation, inflammation, and tumorigenesis. In tumors it is secreted by tumor associated macrophages and can have both pro- and anti-tumorigenic effects. To identify genes regulated by TNFα, we performed a gene trap screen in the mammary carcinoma cell line MCF-7 and recovered 64 unique, TNFα-induced gene trap integration sites. Among these were the genes coding for the zinc finger protein ZC3H10 and for the transcription factor grainyhead-like 3 (GRHL3). In line with the dual effects of TNFα on tumorigenesis, we found that ZC3H10 inhibits anchorage independent growth in soft agar suggesting a tumor suppressor function, whereas GRHL3 strongly stimulated the migration of endothelial cells which is consistent with an angiogenic, pro-tumorigenic function

  5. Induced pluripotent stem cells-derived myeloid-derived suppressor cells regulate the CD8+ T cell response

    Directory of Open Access Journals (Sweden)

    Daniel Joyce

    2018-05-01

    Full Text Available Myeloid-derived suppressor cells (MDSCs are markedly increased in cancer patients and tumor-bearing mice and promote tumor growth and survival by inhibiting host innate and adaptive immunity. In this study, we generated and characterized MDSCs from murine-induced pluripotent stem cells (iPSCs. The iPSCs were co-cultured with OP9 cells, stimulated with GM-CSF, and became morphologically heterologous under co-culturing with hepatic stellate cells. Allogeneic and OVA-specific antigen stimulation demonstrated that iPS-MDSCs have a T-cell regulatory function. Furthermore, a popliteal lymph node assay and autoimmune hepatitis model showed that iPS-MDSCs also regulate immune responsiveness in vivo and have a therapeutic effect against hepatitis. Taken together, our results demonstrated a method of generating functional MDSCs from iPSCs and highlighted the potential of iPS-MDSCs as a key cell therapy resource for transplantation and autoimmune diseases. Keywords: Myeloid-derived suppressor cells, Induced pluripotent stem cells, T cell response

  6. Inhibition of thromboxane synthase induces lung cancer cell death via increasing the nuclear p27

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    Leung, Kin Chung; Hsin, Michael K.Y.; Chan, Joey S.Y.; Yip, Johnson H.Y.; Li, Mingyue; Leung, Billy C.S. [Department of Surgery, The Chinese University of Hong Kong, Shatin, New Territories (Hong Kong); Mok, Tony S.K. [Department of Clinical Oncology, The Chinese University of Hong Kong, Shatin, New Territories (Hong Kong); Warner, Timothy D. [The William Harvey Research Institute, Queen Mary University of London, London (United Kingdom); Underwood, Malcolm J. [Department of Surgery, The Chinese University of Hong Kong, Shatin, New Territories (Hong Kong); Chen, George G., E-mail: gchen@cuhk.edu.hk [Department of Surgery, The Chinese University of Hong Kong, Shatin, New Territories (Hong Kong)

    2009-10-15

    The role of thromboxane in lung carcinogenesis is not clearly known, though thromboxane B2 (TXB{sub 2}) level is increased and antagonists of thromboxane receptors or TXA2 can induce apoptosis of lung cancer cells. p27, an atypical tumor suppressor, is normally sequestered in the nucleus. The increased nuclear p27 may result in apoptosis of tumor cells. We hypothesize that the inhibition of thromboxane synthase (TXS) induces the death of lung cancer cells and that such inhibition is associated with the nuclear p27 level. Our experiment showed that the inhibition of TXS significantly induced the death or apoptosis in lung cancer cells. The activity of TXS was increased in lung cancer. The nuclear p27 was remarkably reduced in lung cancer tissues. The inhibition of TXS caused the cell death and apoptosis of lung cancer cells, likely via the elevation of the nuclear p27 since the TXS inhibition promoted the nuclear p27 level and the inhibition of p27 by its siRNA recovered the cell death induced by TXS inhibition. Collectively, lung cancer cells produce high levels of TXB{sub 2} but their nuclear p27 is markedly reduced. The inhibition of TXS results in the p27-related induction of cell death in lung cancer cells.

  7. Inhibition of thromboxane synthase induces lung cancer cell death via increasing the nuclear p27

    International Nuclear Information System (INIS)

    Leung, Kin Chung; Hsin, Michael K.Y.; Chan, Joey S.Y.; Yip, Johnson H.Y.; Li, Mingyue; Leung, Billy C.S.; Mok, Tony S.K.; Warner, Timothy D.; Underwood, Malcolm J.; Chen, George G.

    2009-01-01

    The role of thromboxane in lung carcinogenesis is not clearly known, though thromboxane B2 (TXB 2 ) level is increased and antagonists of thromboxane receptors or TXA2 can induce apoptosis of lung cancer cells. p27, an atypical tumor suppressor, is normally sequestered in the nucleus. The increased nuclear p27 may result in apoptosis of tumor cells. We hypothesize that the inhibition of thromboxane synthase (TXS) induces the death of lung cancer cells and that such inhibition is associated with the nuclear p27 level. Our experiment showed that the inhibition of TXS significantly induced the death or apoptosis in lung cancer cells. The activity of TXS was increased in lung cancer. The nuclear p27 was remarkably reduced in lung cancer tissues. The inhibition of TXS caused the cell death and apoptosis of lung cancer cells, likely via the elevation of the nuclear p27 since the TXS inhibition promoted the nuclear p27 level and the inhibition of p27 by its siRNA recovered the cell death induced by TXS inhibition. Collectively, lung cancer cells produce high levels of TXB 2 but their nuclear p27 is markedly reduced. The inhibition of TXS results in the p27-related induction of cell death in lung cancer cells.

  8. Murine neonatal spleen contains natural T and non-T suppressor cells capable of inhibiting adult alloreactive and newborn autoreactive T-cell proliferation.

    Science.gov (United States)

    Hooper, D C; Hoskin, D W; Gronvik, K O; Murgita, R A

    1986-05-01

    The spleen of neonatal mice is known to be a rich source of cells capable of suppressing a variety of immune functions of adult lymphocytes in vitro. From such observations has emerged the concept that the gradual development in ability to express immune functions after birth is due in part to the parallel normal physiological decay of naturally occurring regulatory suppressor cells. There is, however, some confusion in the literature as to the exact nature of the newborn of the newborn inhibitory cell type(s). In contrast to most previous reports which detect only a single type of neonatal suppressor cell, usually a T cell, we show here that newborn spleen harbors both T and non-T inhibitory cells. Both types of suppressor cells could be shown to suppress the proliferative response of adult spleen to alloantigens as well as newborn T cells reacting against self-Ia antigen in the autologous mixed lymphocyte reaction (AMLR). Newborn suppressor T cells were characterized as being non-adherent to Ig-anti-Ig affinity columns, soybean agglutinin receptor negative (SBA-), and susceptible to lysis by anti-T-cell specific antiserum plus complement. Non-T suppressor cells were identified as non-phagocytic, SBA receptor positive (SBA+), and resistant to cytotoxic treatment with anti-T-cell antibodies and complement. The apparent controversy surrounding previous reports as to the T versus non-T nature of newborn suppressor cells can be reconciled by the present observation that both types of inhibitory cells coexist in the spleen. Furthermore, the demonstration that newborn suppressor cells can effectively regulate T-cell proliferative activity mediated by other newborn cells provides more direct support for the contention that such inhibitory cells play a physiological role in controlling immune responsiveness during early ontogeny.

  9. Characteristics of DTH suppressor cells in mice infected with Candida albicans.

    Science.gov (United States)

    Valdez, J C; Mesón, O E; Sirena, A; de Alderete, N G

    1987-05-01

    Inoculation of 10(8) C. albicans intraperitoneally into Balb/c mice at given dosage was reported to induce suppression of antigen-specific delayed-type hypersensitivity. Adoptive transfer of spleen cells into normal syngeneic mice pre-treated with Cyclophosphamide confirmed the existence of suppressor cells in mice. Such cells were sensitive to treatment with anti-theta serum and complement, non-adherent to Sephadex G-10. A pretreatment of the mice with Cyclophosphamide eliminated DTH suppression. Treatment with antimacrophage agents via intraperitoneal abrogated suppression only if being effected before inoculation of alive 10(8) Candida albicans. It is concluded that the spleen suppressor cell is a T-lymphocyte whose precursor is Cyclophosphamide-sensitive, requiring the macrophage to be induced.

  10. Natural killer activity and suppressor cells in irradiated mice repopulated with a mixture of cells from normal and 89Sr-treated donors

    International Nuclear Information System (INIS)

    Levy, E.M.; Kumar, V.; Bennett, M.

    1981-01-01

    Mice that have been injected with 89 Sr have fairly normal B and T cell function, but are abnormal in that they lack natural killer (NK) activity and other functions that require an intact bone marrow. These mice also have an increased potential for suppressor cell activity. We had previously shown that spleen cells from 89 Sr-treated mice could transfer low NK activity and increased suppressor cell function to lethally irradiated syngeneic recipients. To investigate the mechanisms involved in perpetuating these defects, groups of normal spleen or bone marrow cells. Recipients were assayed for their NK activity and suppressor cell function 5 to 14 wk later. it was found that the addition of normal cells in the donor inoculum resulted in normal NK activity. This indicates that low NK activity in 89 Sr-treated mice was not due to the presence of a suppressor cell that prevented NK cell generation. It was additionally found that low NK activity in recipient mice could be boosted by interferon inducers. This would indicate that NK activity in the recipients was not due to a lack of interferon-sensitive pre-NK cells. Suppressor cell function in recipient mice depended on the type and number of normal cells in the donor inoculum. Bone marrow cells were very efficient in overcoming the tendency to produce suppressor cells. It took approximately 20 times more normal spleen cells to produce the same results. The implications of these findings are discussed

  11. Immunoregulatory T cells in man. Histamine-induced suppressor T cells are derived from a Leu 2+ (T8+) subpopulation distinct from that which gives rise to cytotoxic T cells

    International Nuclear Information System (INIS)

    Sansoni, P.; Silverman, E.D.; Khan, M.M.; Melmon, K.L.; Engleman, E.G.

    1985-01-01

    One mechanism of histamine-mediated inhibition of the immune response in man is to activate T suppressor cells that bear the Leu 2 (OKT8) marker. The current study was undertaken to characterize the histamine-induced suppressor cell using a monoclonal antibody (9.3) shown previously to distinguish cytotoxic T cells from antigen-specific suppressor T cells. Leu 2+ cells isolated from peripheral blood were further separated with antibody 9.3 into Leu 2+, 9.3+, and Leu 2+, 9.3- subsets and each subset was incubated with different concentrations of histamine before determining their ability to suppress immune responses in vitro. The results indicate that the Leu 2+, 9.3- subpopulation includes all histamine-induced suppressor cells, that 10(-4) M histamine is the optimal concentration for suppressor cell induction, and that exposure of Leu 2+, 9.3- cells to histamine for 30 s is sufficient to initiate the induction process. After treatment with histamine these cells inhibit both phytohemagglutinin-induced T cell proliferation and pokeweed mitogen-induced B cell differentiation. The suppression of phytohemagglutinin-induced proliferation was resistant to x-irradiation with 1,200 rad, either before or after histamine exposure, suggesting that Leu 2+, 9.3- cells need not proliferate to become suppressor cells or exert suppression. Moreover, suppression by these cells was not due to altered kinetics of the response. Finally, a histamine type 2 receptor antagonist (cimetidine) but not a type 1 receptor antagonist (mepyramine) blocked the induction of suppressor cells. On the basis of these results and our previous studies of antigen specific suppressor cells, we conclude that Leu 2+ suppressor cells in man are derived from a precursor pool that is phenotypically distinct from cells that can differentiate into cytotoxic T cells

  12. Macrophage p53 controls macrophage death in atherosclerotic lesions of apolipoprotein E deficient mice

    NARCIS (Netherlands)

    Boesten, L.S.M.; Zadelaar, A.S.M.; Nieuwkoop, A. van; Hu, L.; Teunisse, A.F.A.S.; Jochemsen, A.G.; Evers, B.; Water, B. van de; Gijbels, M.J.J.; Vlijmen, B.J.M. van; Havekes, L.M.; Winther, M.P.J. de

    2009-01-01

    The cellular composition of atherosclerotic lesions is determined by many factors including cell infiltration, proliferation and cell death. Tumor suppressor gene p53 has been shown to regulate both cell proliferation and cell death in many cell types. In the present study, we investigated the role

  13. Effector and naturally occurring regulatory T cells display no abnormalities in activation induced cell death in NOD mice.

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    Ayelet Kaminitz

    Full Text Available BACKGROUND: Disturbed peripheral negative regulation might contribute to evolution of autoimmune insulitis in type 1 diabetes. This study evaluates the sensitivity of naïve/effector (Teff and regulatory T cells (Treg to activation-induced cell death mediated by Fas cross-linking in NOD and wild-type mice. PRINCIPAL FINDINGS: Both effector (CD25(-, FoxP3(- and suppressor (CD25(+, FoxP3(+ CD4(+ T cells are negatively regulated by Fas cross-linking in mixed splenocyte populations of NOD, wild type mice and FoxP3-GFP trangeneess. Proliferation rates and sensitivity to Fas cross-linking are dissociated in Treg cells: fast cycling induced by IL-2 and CD3/CD28 stimulation improve Treg resistance to Fas-ligand (FasL in both strains. The effector and suppressor CD4(+ subsets display balanced sensitivity to negative regulation under baseline conditions, IL-2 and CD3/CD28 stimulation, indicating that stimulation does not perturb immune homeostasis in NOD mice. Effective autocrine apoptosis of diabetogenic cells was evident from delayed onset and reduced incidence of adoptive disease transfer into NOD.SCID by CD4(+CD25(- T cells decorated with FasL protein. Treg resistant to Fas-mediated apoptosis retain suppressive activity in vitro. The only detectable differential response was reduced Teff proliferation and upregulation of CD25 following CD3-activation in NOD mice. CONCLUSION: These data document negative regulation of effector and suppressor cells by Fas cross-linking and dissociation between sensitivity to apoptosis and proliferation in stimulated Treg. There is no evidence that perturbed AICD in NOD mice initiates or promotes autoimmune insulitis.

  14. The tumor suppressor gene Trp53 protects the mouse lens against posterior subcapsular cataracts and the BMP receptor Acvr1 acts as a tumor suppressor in the lens

    Directory of Open Access Journals (Sweden)

    Luke A. Wiley

    2011-07-01

    We previously found that lenses lacking the Acvr1 gene, which encodes a bone morphogenetic protein (BMP receptor, had abnormal proliferation and cell death in epithelial and cortical fiber cells. We tested whether the tumor suppressor protein p53 (encoded by Trp53 affected this phenotype. Acvr1 conditional knockout (Acvr1CKO mouse fiber cells had increased numbers of nuclei that stained for p53 phosphorylated on serine 15, an indicator of p53 stabilization and activation. Deletion of Trp53 rescued the Acvr1CKO cell death phenotype in embryos and reduced Acvr1-dependent apoptosis in postnatal lenses. However, deletion of Trp53 alone increased the number of fiber cells that failed to withdraw from the cell cycle. Trp53CKO and Acvr1;Trp53DCKO (double conditional knockout, but not Acvr1CKO, lenses developed abnormal collections of cells at the posterior of the lens that resembled posterior subcapsular cataracts. Cells from human posterior subcapsular cataracts had morphological and molecular characteristics similar to the cells at the posterior of mouse lenses lacking Trp53. In Trp53CKO lenses, cells in the posterior plaques did not proliferate but, in Acvr1;Trp53DCKO lenses, many cells in the posterior plaques continued to proliferate, eventually forming vascularized tumor-like masses at the posterior of the lens. We conclude that p53 protects the lens against posterior subcapsular cataract formation by suppressing the proliferation of fiber cells and promoting the death of any fiber cells that enter the cell cycle. Acvr1 acts as a tumor suppressor in the lens. Enhancing p53 function in the lens could contribute to the prevention of steroid- and radiation-induced posterior subcapsular cataracts.

  15. Effect of irradiation on human T-cell proliferation: low dose irradiation stimulates mitogen-induced proliferation and function of the suppressor/cytotoxic T-cell subset

    International Nuclear Information System (INIS)

    Gualde, N.; Goodwin, J.S.

    1984-01-01

    Unfractionated human T cells exposed to 10-50 rad of X irradiation incorporated less [ 3 H]thymidine than nonirradiated T cells when subsequently cultured with PHA or Con A. The cytotoxic/suppressor T-cell subset, isolated as either OKT8(+) or OKT4(-) cells, demonstrated significantly enhanced [ 3 H]thymidine incorporation in PHA- or Con A-stimulated cultures after exposure to 10-50 rad, compared to unirradiated cells, while the proliferation of the OKT4(+) helper/inducer subset was inhibited by low dose irradiation. It has been previously reported that approximately 30% of the cytotoxic/suppressor subset also stains with OKM1. When the cytotoxic/suppressor subset was further subdivided into OKT4(-), OKM1(+), and OKT4(-), OKM1(-) cells, proliferation of the OKT4(-), OKM1(+) population was inhibited by exposure to 25 rad while proliferation of the OKT4(-), OKM1(-) population was stimulated. The increase in proliferation of the cytotoxic/suppressor T-cell subset after low dose irradiation is paralleled by an increase in suppressor activity of these cells. T cells exposed to 25 rad and then cultured with Con A for 48 hr caused greater inhibition of IgG production when added to fresh autologous lymphocytes stimulated by pokeweed mitogen than did unirradiated cells. Thus, low dose irradiation enhances both the proliferation and function of the human suppressor T-cell subset

  16. Alloantigen-specific suppressor T cells are not inhibited by cyclosporin A, but do require IL 2 for activation

    International Nuclear Information System (INIS)

    Bucy, R.P.

    1986-01-01

    Alloantigen-specific suppressor T cells are activated from normal murine spleen cells in mixed lymphocyte reactions (MLR). These T cells are radioresistant and suppress the activation of cytotoxic T lymphocytes (CTL) in second primary MLR cultures. This report demonstrates that cyclosporin A (CsA) blocks the activation of these suppressor cells at a dose of 1 microgram/ml. However, reconstitution of CsA blocked cultures with IL 2 restores the activation of the suppressor T cells, but fails to significantly restore the activation of CTL in these same cultures. This differential activation requirement was used to establish T cell lines that demonstrate enriched suppressor cell activity but depletion of CTL activity. These findings are discussed in terms of the mechanism of action of CsA in these distinct T cell subsets and the relevance to models of allograft unresponsiveness

  17. The Ras suppressor-1 (RSU-1 in cancer

    Directory of Open Access Journals (Sweden)

    Lefteris C Zacharia

    2017-04-01

    Full Text Available Primary tumors are seldom the cause of death for cancer patients as most patients die from metastatic disease. Thus, deciphering metastatic mechanisms and key molecules involved is of utmost importance for the improved survival of cancer patients. Metastasis is a complex process in which cancer cells dissociate from the original tumor and spread to distant sites of the body. During the metastatic process, cancer cells lose contact both with the extracellular matrix (ECM and the neighboring cells within the primary tumor, thus invading though surrounding tissues. Therefore, ECM, and ECM-related adhesion proteins play a critical role in the metastatic process. Ras suppressor-1 (RSU-1 was first identified as a suppressor of Ras-dependent oncogenic transformation and is localized to cell-ECM adhesions where it is known to interact with the pro-survival adhesion protein PINCH-1. Although the connection to cancer is obvious, little is known regarding its expression in various cancer types. This opinion piece is focusing on recent literature regarding the expression of RSU-1 in various cancer types and the possible molecular mechanism of its action, pointing towards questions that need still to be addressed in this research field.

  18. Curcumin attenuates paraquat-induced cell death in human neuroblastoma cells through modulating oxidative stress and autophagy.

    Science.gov (United States)

    Jaroonwitchawan, Thiranut; Chaicharoenaudomrung, Nipha; Namkaew, Jirapat; Noisa, Parinya

    2017-01-01

    Paraquat is a neurotoxic agent, and oxidative stress plays an important role in neuronal cell death after paraquat exposure. In this study, we assessed the neuroprotective effect of curcumin against paraquat and explored the underlying mechanisms of curcumin in vitro. Curcumin treatment prevented paraquat-induced reactive oxygen species (ROS) and apoptotic cell death. Curcumin also exerted a neuroprotective effect by increasing the expression of anti-apoptotic and antioxidant genes. The pretreatment of curcumin significantly decreased gene expression and protein production of amyloid precursor protein. The activation of autophagy process was found defective in paraquat-induced cells, indicated by the accumulation and reduction of LC3I/II. Noteworthy, curcumin restored LC3I/II expression after the pretreatment. Collectively, curcumin demonstrated as a prominent suppressor of ROS, and could reverse autophagy induction in SH-SY5Y cells. The consequences of this were the reduction of APP production and prevention of SH-SY5Y cells from apoptosis. Altogether, curcumin potentially serves as a therapeutic agent of neurodegenerative diseases, associated with ROS overproduction and autophagy dysfunction. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Expression of programmed cell death protein 4 (PDCD4) and miR-21 in urothelial carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Nicolas, E-mail: simplissimus@gmx.de [Department of Urology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Goeke, Friederike, E-mail: Friederike.goeke@ukb.uni-bonn.de [Department of Pathology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Splittstoesser, Vera, E-mail: Veri.sp@web.de [Department of Urology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Lankat-Buttgereit, Brigitte, E-mail: Lankatbu@staff.uni-marburg.de [Department of Internal Medicine, Philipps-University of Marburg, Baldingerstrasse, 35043 Marburg (Germany); Mueller, Stefan C., E-mail: Stefan.mueller@ukb.uni-bonn.de [Department of Urology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Ellinger, Joerg, E-mail: Joerg.ellinger@ukb.uni-bonn.de [Department of Urology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer The tumor suppressor gene PDCD4 is down-regulated in many tumorous entities. Black-Right-Pointing-Pointer We investigate the impact of PDCD4 and its regulating factor miR-21 in urothelial carcinoma. Black-Right-Pointing-Pointer We confirm PDCD4 as a tumor suppressor gene and it could be a diagnostic marker for this tumor. -- Abstract: Background: We investigated the role of the programmed cell death 4 (PDCD4) tumor suppressor gene in specimens of transitional cell carcinoma and of healthy individuals. Methods: PDCD4 immunohistochemical expression was investigated in 294 cases in histologically proven transitional cell carcinoma in different tumorous stages (28 controls, 122 non-muscle invasive urothelial carcinoma, stages Tis-T1, 119 invasive transitional cell carcinoma stages T2-T4 and 25 metastases). MiR-21 expression, an important PDCD4 regulator, was assessed with real-time PCR analysis and showed inverse correlation to tissue PDCD4 expression. Results: Nuclear and cytoplasmatic PDCD4 immunostaining decreased significantly with histopathological progression of the tumor (p < 0001). Controls showed strong nuclear and cytoplasmatic immunohistochemical staining. MiR-21 up regulation in tissue corresponded to PDCD4 suppression. Conclusions: These data support a decisive role for PDCD4 down regulation in transitional cell carcinoma and confirm miR-21 as a negative regulator for PDCD4. Additionally, PDCD4 immunohistochemical staining turns out to be a possible diagnostic marker for transitional cell carcinoma.

  20. Expression of programmed cell death protein 4 (PDCD4) and miR-21 in urothelial carcinoma

    International Nuclear Information System (INIS)

    Fischer, Nicolas; Göke, Friederike; Splittstößer, Vera; Lankat-Buttgereit, Brigitte; Müller, Stefan C.; Ellinger, Jörg

    2012-01-01

    Highlights: ► The tumor suppressor gene PDCD4 is down-regulated in many tumorous entities. ► We investigate the impact of PDCD4 and its regulating factor miR-21 in urothelial carcinoma. ► We confirm PDCD4 as a tumor suppressor gene and it could be a diagnostic marker for this tumor. -- Abstract: Background: We investigated the role of the programmed cell death 4 (PDCD4) tumor suppressor gene in specimens of transitional cell carcinoma and of healthy individuals. Methods: PDCD4 immunohistochemical expression was investigated in 294 cases in histologically proven transitional cell carcinoma in different tumorous stages (28 controls, 122 non-muscle invasive urothelial carcinoma, stages Tis-T1, 119 invasive transitional cell carcinoma stages T2–T4 and 25 metastases). MiR-21 expression, an important PDCD4 regulator, was assessed with real-time PCR analysis and showed inverse correlation to tissue PDCD4 expression. Results: Nuclear and cytoplasmatic PDCD4 immunostaining decreased significantly with histopathological progression of the tumor (p < 0001). Controls showed strong nuclear and cytoplasmatic immunohistochemical staining. MiR-21 up regulation in tissue corresponded to PDCD4 suppression. Conclusions: These data support a decisive role for PDCD4 down regulation in transitional cell carcinoma and confirm miR-21 as a negative regulator for PDCD4. Additionally, PDCD4 immunohistochemical staining turns out to be a possible diagnostic marker for transitional cell carcinoma.

  1. p53 dependent apoptotic cell death induces embryonic malformation in Carassius auratus under chronic hypoxia.

    Directory of Open Access Journals (Sweden)

    Paramita Banerjee Sawant

    Full Text Available Hypoxia is a global phenomenon affecting recruitment as well as the embryonic development of aquatic fauna. The present study depicts hypoxia induced disruption of the intrinsic pathway of programmed cell death (PCD, leading to embryonic malformation in the goldfish, Carrasius auratus. Constant hypoxia induced the early expression of pro-apoptotic/tumor suppressor p53 and concomitant expression of the cell death molecule, caspase-3, leading to high level of DNA damage and cell death in hypoxic embryos, as compared to normoxic ones. As a result, the former showed delayed 4 and 64 celled stages and a delay in appearance of epiboly stage. Expression of p53 efficiently switched off expression of the anti-apoptotic Bcl-2 during the initial 12 hours post fertilization (hpf and caused embryonic cell death. However, after 12 hours, simultaneous downregulation of p53 and Caspase-3 and exponential increase of Bcl-2, caused uncontrolled cell proliferation and prevented essential programmed cell death (PCD, ultimately resulting in significant (p<0.05 embryonic malformation up to 144 hpf. Evidences suggest that uncontrolled cell proliferation after 12 hpf may have been due to downregulation of p53 abundance, which in turn has an influence on upregulation of anti-apoptotic Bcl-2. Therefore, we have been able to show for the first time and propose that hypoxia induced downregulation of p53 beyond 12 hpf, disrupts PCD and leads to failure in normal differentiation, causing malformation in gold fish embryos.

  2. CMTM5 exhibits tumor suppressor activity through promoter methylation in oral squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Heyu [Central Laboratory, Peking University School of Stomatology, Beijing (China); Nan, Xu [Center for Human Disease Genomics, Department of Immunology, Key Laboratory of Medical Immunology, Ministry of Health, School of Basic Medical Sciences, Peking University, Beijing (China); Li, Xuefen [Central Laboratory, Peking University School of Stomatology, Beijing (China); Chen, Yan; Zhang, Jianyun [Department of Oral Pathology, Peking University School of Stomatology, Beijing (China); Sun, Lisha [Central Laboratory, Peking University School of Stomatology, Beijing (China); Han, Wenlin [Center for Human Disease Genomics, Department of Immunology, Key Laboratory of Medical Immunology, Ministry of Health, School of Basic Medical Sciences, Peking University, Beijing (China); Li, Tiejun, E-mail: litiejun22@vip.sina.com [Department of Oral Pathology, Peking University School of Stomatology, Beijing (China)

    2014-05-02

    Highlights: • Down-regulation of CMTM5 expression in OSCC tissues was found. • The promoter methylation status of CMTM5 was measured. • CMTM5-v1 inhibited cell proliferation and migration and induced apoptosis. • CMTM5 might act as a putative tumor suppressor gene in OSCC. - Abstract: Oral squamous cell carcinoma (OSCC) is one of the most common types of malignancies in the head and neck region. CKLF-like MARVEL transmembrane domain-containing member 5 (CMTM5) has been recently implicated as a tumor suppressor gene in several cancer types. Herein, we examined the expression and function of CMTM5 in oral squamous cell carcinoma. CMTM5 was down-regulated in oral squamous cell lines and tumor samples from patients with promoter methylation. Treatment with the demethylating agent 5-aza-2′-deoxycytidine restored CMTM5 expression. In the OSCC cell lines CAL27 and GNM, the ectopic expression of CMTM5-v1 strongly inhibited cell proliferation and migration and induced apoptosis. In addition, CMTM5-v1 inhibited tumor formation in vivo. Therefore, CMTM5 might act as a putative tumor suppressor gene through promoter methylation in oral squamous cell carcinoma.

  3. CMTM5 exhibits tumor suppressor activity through promoter methylation in oral squamous cell carcinoma

    International Nuclear Information System (INIS)

    Zhang, Heyu; Nan, Xu; Li, Xuefen; Chen, Yan; Zhang, Jianyun; Sun, Lisha; Han, Wenlin; Li, Tiejun

    2014-01-01

    Highlights: • Down-regulation of CMTM5 expression in OSCC tissues was found. • The promoter methylation status of CMTM5 was measured. • CMTM5-v1 inhibited cell proliferation and migration and induced apoptosis. • CMTM5 might act as a putative tumor suppressor gene in OSCC. - Abstract: Oral squamous cell carcinoma (OSCC) is one of the most common types of malignancies in the head and neck region. CKLF-like MARVEL transmembrane domain-containing member 5 (CMTM5) has been recently implicated as a tumor suppressor gene in several cancer types. Herein, we examined the expression and function of CMTM5 in oral squamous cell carcinoma. CMTM5 was down-regulated in oral squamous cell lines and tumor samples from patients with promoter methylation. Treatment with the demethylating agent 5-aza-2′-deoxycytidine restored CMTM5 expression. In the OSCC cell lines CAL27 and GNM, the ectopic expression of CMTM5-v1 strongly inhibited cell proliferation and migration and induced apoptosis. In addition, CMTM5-v1 inhibited tumor formation in vivo. Therefore, CMTM5 might act as a putative tumor suppressor gene through promoter methylation in oral squamous cell carcinoma

  4. A Trichostatin A (TSA)/Sp1-mediated mechanism for the regulation of SALL2 tumor suppressor in Jurkat T cells.

    Science.gov (United States)

    Hepp, Matías I; Escobar, David; Farkas, Carlos; Hermosilla, Viviana; Álvarez, Claudia; Amigo, Roberto; Gutiérrez, José L; Castro, Ariel F; Pincheira, Roxana

    2018-05-17

    SALL2 is a transcription factor involved in development and disease. Deregulation of SALL2 has been associated with cancer, suggesting that it plays a role in the disease. However, how SALL2 is regulated and why is deregulated in cancer remain poorly understood. We previously showed that the p53 tumor suppressor represses SALL2 under acute genotoxic stress. Here, we investigated the effect of Histone Deacetylase Inhibitor (HDACi) Trichostatin A (TSA), and involvement of Sp1 on expression and function of SALL2 in Jurkat T cells. We show that SALL2 mRNA and protein levels were enhanced under TSA treatment. Both, TSA and ectopic expression of Sp1 transactivated the SALL2 P2 promoter. This transactivation effect was blocked by the Sp1-binding inhibitor mithramycin A. Sp1 bound in vitro and in vivo to the proximal region of the P2 promoter. TSA induced Sp1 binding to the P2 promoter, which correlated with dynamic changes on H4 acetylation and concomitant recruitment of p300 or HDAC1 in a mutually exclusive manner. Our results suggest that TSA-induced Sp1-Lys703 acetylation contributes to the transcriptional activation of the P2 promoter. Finally, using a CRISPR/Cas9 SALL2-KO Jurkat-T cell model and gain of function experiments, we demonstrated that SALL2 upregulation is required for TSA-mediated cell death. Thus, our study identified Sp1 as a novel transcriptional regulator of SALL2, and proposes a novel epigenetic mechanism for SALL2 regulation in Jurkat-T cells. Altogether, our data support SALL2 function as a tumor suppressor, and SALL2 involvement in cell death response to HDACi. Copyright © 2018. Published by Elsevier B.V.

  5. Control of polyclonal immunoglobulin production from human lymphocytes by leukotrienes; leukotriene B4 induces an OKT8(+), radiosensitive suppressor cell from resting, human OKT8(-) T cells

    International Nuclear Information System (INIS)

    Atluru, D.; Goodwin, J.S.

    1984-01-01

    We report that leukotriene B4 (LTB4), a 5-lipoxygenase metabolite of arachidonic acid, is a potent suppressor of polyclonal Ig production in pokeweed mitogen (PWM)-stimulated cultures of human peripheral blood lymphocytes, while LTC4 and LTD4 have little activity in this system. Preincubation of T cells with LTB4 in nanomolar to picomolar concentrations rendered these cells suppressive of Ig production in subsequent PWM-stimulated cultures of fresh, autologous B + T cells. This LTB4-induced suppressor cell was radiosensitive, and its generation could be blocked by cyclohexamide but not by mitomycin C. The LTB4-induced suppressor cell was OKT8(+), while the precursor for the cell could be OKT8(-). The incubation of OKT8(-) T cells with LTB4 for 18 h resulted in the appearance of the OKT8(+) on 10-20% of the cells, and this could be blocked by cyclohexamide but not by mitomycin C. Thus, LTB4 in very low concentrations induces a radiosensitive OKT8(+) suppressor cell from OKT8(-) cells. In this regard, LTB4 is three to six orders of magnitude more potent than any endogenous hormonal inducer of suppressor cells previously described. Glucocorticosteroids, which block suppressor cell induction in many systems, may act by inhibiting endogenous production of LTB4

  6. The silencing suppressor (NSs) protein of the plant virus Tomato spotted wilt virus enhances heterologous protein expression and baculovirus pathogenicity in cells and lepidopteran insects.

    Science.gov (United States)

    de Oliveira, Virgínia Carla; da Silva Morgado, Fabricio; Ardisson-Araújo, Daniel Mendes Pereira; Resende, Renato Oliveira; Ribeiro, Bergmann Morais

    2015-11-01

    In this work, we showed that cell death induced by a recombinant (vAcNSs) Autographa californica multiple nucleopolyhedrovirus (AcMNPV) expressing the silencing suppressor (NSs) protein of Tomato spotted wilt virus (TSWV) was enhanced on permissive and semipermissive cell lines. The expression of a heterologous gene (firefly luciferase) during co-infection of insect cells with vAcNSs and a second recombinant baculovirus (vAgppolhfluc) was shown to increase when compared to single vAgppolhfluc infections. Furthermore, the vAcNSs mean time-to-death values were significantly lower than those for wild-type AcMNPV on larvae of Spodoptera frugiperda and Anticarsia gemmatalis. These results showed that the TSWV-NSs protein could efficiently increase heterologous protein expression in insect cells as well as baculovirus pathogenicity and virulence, probably by suppressing the gene-silencing machinery in insects.

  7. Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells

    Science.gov (United States)

    Iessi, Elisabetta; Zischler, Luciana; Etringer, Aurélie; Bergeret, Marion; Morlé, Aymeric; Jacquemin, Guillaume; Morizot, Alexandre; Shirley, Sarah; Lalaoui, Najoua; Elifio-Esposito, Selene L.; Fais, Stefano; Garrido, Carmen; Solary, Eric; Micheau, Olivier

    2015-01-01

    Ezrin belongs to the ERM (ezrin-radixin-moesin) protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells. PMID:26010871

  8. Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Elisabetta Iessi

    Full Text Available Ezrin belongs to the ERM (ezrin-radixin-moesin protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells.

  9. Clinical impact of the immunome in lymphoid malignancies: the role of Myeloid-Derived Suppressor Cells

    Directory of Open Access Journals (Sweden)

    Calogero eVetro

    2015-05-01

    Full Text Available The better definition of the mutual sustainment between neoplastic cells and immune system has been translated from the bench to the bedside acquiring value as prognostic factor. Additionally, it represents a promising tool for improving therapeutic strategies. In this context, myeloid-derived suppressor cells have gained a central role in tumor developing with consequent therapeutic implications. In this review, we will focus on the biological and clinical impact of the study of myeloid-derived suppressor cells in the settings of lymphoid malignancies.

  10. Microarray Analysis in a Cell Death Resistant Glioma Cell Line to Identify Signaling Pathways and Novel Genes Controlling Resistance and Malignancy

    Energy Technology Data Exchange (ETDEWEB)

    Seznec, Janina; Naumann, Ulrike, E-mail: ulrike.naumann@uni-tuebingen.de [Laboratory of Molecular Neuro-Oncology, Department of General Neurology, Hertie-Institute for Clinical Brain Research and Center Neurology, University of Tuebingen, Otfried-Mueller-Str. 27, Tuebingen 72076 (Germany)

    2011-06-27

    Glioblastoma multiforme (GBM) is a lethal type of cancer mainly resistant to radio- and chemotherapy. Since the tumor suppressor p53 functions as a transcription factor regulating the expression of genes involved in growth inhibition, DNA repair and apoptosis, we previously assessed whether specific differences in the modulation of gene expression are responsible for the anti-tumor properties of a dominant positive p53, chimeric tumor suppressor (CTS)-1. CTS-1 is based on the sequence of p53 and designed to resist various mechanisms of inactivation which limit the activity of p53. To identify CTS-1-regulated cell death-inducing genes, we generated a CTS-1-resistant glioma cell line (229R). We used Affymetrix whole-genome microarray expression analysis to analyze alterations in gene expression and identified a variety of CTS-1 regulated genes involved in cancer-linked processes. 313 genes were differentially expressed in Adeno-CTS-1 (Ad-CTS-1)-infected and 700 genes in uninfected 229R cells compared to matching parental cells. Ingenuity Pathway Analysis (IPA) determined a variety of differentially expressed genes in Ad-CTS-1-infected cells that were members of the intracellular networks with central tumor-involved players such as nuclear factor kappa B (NF-κB), protein kinase B (PKB/AKT) or transforming growth factor beta (TGF-β). Differentially regulated genes include secreted factors as well as intracellular proteins and transcription factors regulating not only cell death, but also processes such as tumor cell motility and immunity. This work gives an overview of the pathways differentially regulated in the resistant versus parental glioma cells and might be helpful to identify candidate genes which could serve as targets to develop novel glioma specific therapy strategies.

  11. Microarray Analysis in a Cell Death Resistant Glioma Cell Line to Identify Signaling Pathways and Novel Genes Controlling Resistance and Malignancy

    International Nuclear Information System (INIS)

    Seznec, Janina; Naumann, Ulrike

    2011-01-01

    Glioblastoma multiforme (GBM) is a lethal type of cancer mainly resistant to radio- and chemotherapy. Since the tumor suppressor p53 functions as a transcription factor regulating the expression of genes involved in growth inhibition, DNA repair and apoptosis, we previously assessed whether specific differences in the modulation of gene expression are responsible for the anti-tumor properties of a dominant positive p53, chimeric tumor suppressor (CTS)-1. CTS-1 is based on the sequence of p53 and designed to resist various mechanisms of inactivation which limit the activity of p53. To identify CTS-1-regulated cell death-inducing genes, we generated a CTS-1-resistant glioma cell line (229R). We used Affymetrix whole-genome microarray expression analysis to analyze alterations in gene expression and identified a variety of CTS-1 regulated genes involved in cancer-linked processes. 313 genes were differentially expressed in Adeno-CTS-1 (Ad-CTS-1)-infected and 700 genes in uninfected 229R cells compared to matching parental cells. Ingenuity Pathway Analysis (IPA) determined a variety of differentially expressed genes in Ad-CTS-1-infected cells that were members of the intracellular networks with central tumor-involved players such as nuclear factor kappa B (NF-κB), protein kinase B (PKB/AKT) or transforming growth factor beta (TGF-β). Differentially regulated genes include secreted factors as well as intracellular proteins and transcription factors regulating not only cell death, but also processes such as tumor cell motility and immunity. This work gives an overview of the pathways differentially regulated in the resistant versus parental glioma cells and might be helpful to identify candidate genes which could serve as targets to develop novel glioma specific therapy strategies

  12. Tumor suppressor WWOX and p53 alterations and drug resistance in glioblastomas

    Directory of Open Access Journals (Sweden)

    Ming-Fu eChiang

    2013-03-01

    Full Text Available Tumor suppressor p53 are frequently mutated in glioblastomas (GBMs and appears to contribute, in part, to resistance to temozolomide and therapeutic drugs. WW domain-containing oxidoreductase WWOX (FOR or WOX1 is a proapoptotic protein and is considered as a tumor suppressor. Loss of WWOX gene expression is frequently seen in malignant cancer cells due to promoter hypermethylation, genetic alterations, and translational blockade. Intriguingly, ectopic expression of wild type WWOX preferentially induces apoptosis in human glioblastoma cells harboring mutant p53. WWOX is known to physically bind and stabilize wild type p53. Here, we provide an overview for the updated knowledge in p53 and WWOX, and postulate a potential scenarios that wild type and mutant p53, or isoforms, modulate the apoptotic function of WWOX. We propose that triggering WWOX activation by therapeutic drugs under p53 functional deficiency is needed to overcome TMZ resistance and induce GBM cell death.

  13. Induction of CD4 suppressor T cells with anti-Leu-8 antibody

    International Nuclear Information System (INIS)

    Kanof, M.E.; Strober, W.; James, S.P.

    1987-01-01

    To characterize the conditions under which CD4 T cells suppress polyclonal immunoglobulin synthesis, we investigated the capacity of CD4 T cells that coexpress the surface antigen recognized by the monoclonal antibody anti-Leu-8 to mediate suppression. In an in vitro system devoid of CD8 T cells, CD4, Leu-8+ T cells suppressed pokeweed mitogen-induced immunoglobulin synthesis. Similarly, suppressor function was induced in unfractionated CD4 T cell populations after incubation with anti-Leu-8 antibody under cross-linking conditions. This induction of suppressor function by anti-Leu-8 antibody was not due to expansion of the CD4, Leu-8+ T cell population because CD4 T cells did not proliferate in response to anti-Leu-8 antibody. However, CD4, Leu-8+ T cell-mediated suppression was radiosensitive. Finally, CD4, Leu-8+ T cells do not inhibit immunoglobulin synthesis when T cell lymphokines were used in place of helper CD4 T cells (CD4, Leu-8- T cells), suggesting that CD4 T cell-mediated suppression occurs at the T cell level. We conclude that CD4 T cells can be induced to suppress immunoglobulin synthesis by modulation of the membrane antigen recognized by anti-Leu-8 antibody

  14. IL-1beta-induced chemokine and Fas expression are inhibited by suppressor of cytokine signalling-3 in insulin-producing cells

    DEFF Research Database (Denmark)

    Jacobsen, M L B; Rønn, S G; Bruun, C

    2008-01-01

    AIMS/HYPOTHESIS: Chemokines recruit activated immune cells to sites of inflammation and are important mediators of insulitis. Activation of the pro-apoptotic receptor Fas leads to apoptosis-mediated death of the Fas-expressing cell. The pro-inflammatory cytokines IL-1beta and IFN-gamma regulate...... the transcription of genes encoding the Fas receptor and several chemokines. We have previously shown that suppressor of cytokine signalling (SOCS)-3 inhibits IL-1beta- and IFN-gamma-induced nitric oxide production in a beta cell line. The aim of this study was to investigate whether SOCS-3 can influence cytokine......-induced Fas and chemokine expression in beta cells. METHODS: Using a beta cell line with inducible Socs3 expression or primary neonatal rat islet cells transduced with a Socs3-encoding adenovirus, we employed real-time RT-PCR analysis to investigate whether SOCS-3 affects cytokine-induced chemokine and Fas m...

  15. Reduction of myeloid-derived suppressor cells and lymphoma growth by a natural triterpenoid.

    Science.gov (United States)

    Radwan, Faisal F Y; Hossain, Azim; God, Jason M; Leaphart, Nathan; Elvington, Michelle; Nagarkatti, Mitzi; Tomlinson, Stephen; Haque, Azizul

    2015-01-01

    Lymphoma is a potentially life threatening disease. The goal of this study was to investigate the therapeutic potential of a natural triterpenoid, Ganoderic acid A (GA-A) in controlling lymphoma growth both in vitro and in vivo. Here, we show that GA-A treatment induces caspase-dependent apoptotic cell death characterized by a dose-dependent increase in active caspases 9 and 3, up-regulation of pro-apoptotic BIM and BAX proteins, and a subsequent loss of mitochondrial membrane potential with release of cytochrome c. In addition to GA-A's anti-growth activity, we show that lower doses of GA-A enhance HLA class II-mediated antigen (Ag) presentation and CD4+ T cell recognition of lymphoma cells in vitro. The therapeutic relevance of GA-A treatment was also tested in vivo using the EL4 syngeneic mouse model of metastatic lymphoma. GA-A-treatment significantly prolonged survival of EL4 challenged mice and decreased tumor metastasis to the liver, an outcome accompanied by a marked down-regulation of STAT3 phosphorylation, reduction myeloid-derived suppressor cells (MDSCs), and enhancement of cytotoxic CD8+ T cells in the host. Thus, GA-A not only selectively induces apoptosis in lymphoma cells, but also enhances cell-mediated immune responses by attenuating MDSCs, and elevating Ag presentation and T cell recognition. The demonstrated therapeutic benefit indicates that GA-A is a candidate for future drug design for the treatment of lymphoma. © 2014 Wiley Periodicals, Inc.

  16. Cell size checkpoint control by the retinoblastoma tumor suppressor pathway.

    Science.gov (United States)

    Fang, Su-Chiung; de los Reyes, Chris; Umen, James G

    2006-10-13

    Size control is essential for all proliferating cells, and is thought to be regulated by checkpoints that couple cell size to cell cycle progression. The aberrant cell-size phenotypes caused by mutations in the retinoblastoma (RB) tumor suppressor pathway are consistent with a role in size checkpoint control, but indirect effects on size caused by altered cell cycle kinetics are difficult to rule out. The multiple fission cell cycle of the unicellular alga Chlamydomonas reinhardtii uncouples growth from division, allowing direct assessment of the relationship between size phenotypes and checkpoint function. Mutations in the C. reinhardtii RB homolog encoded by MAT3 cause supernumerous cell divisions and small cells, suggesting a role for MAT3 in size control. We identified suppressors of an mat3 null allele that had recessive mutations in DP1 or dominant mutations in E2F1, loci encoding homologs of a heterodimeric transcription factor that is targeted by RB-related proteins. Significantly, we determined that the dp1 and e2f1 phenotypes were caused by defects in size checkpoint control and were not due to a lengthened cell cycle. Despite their cell division defects, mat3, dp1, and e2f1 mutants showed almost no changes in periodic transcription of genes induced during S phase and mitosis, many of which are conserved targets of the RB pathway. Conversely, we found that regulation of cell size was unaffected when S phase and mitotic transcription were inhibited. Our data provide direct evidence that the RB pathway mediates cell size checkpoint control and suggest that such control is not directly coupled to the magnitude of periodic cell cycle transcription.

  17. Ras and Rheb Signaling in Survival and Cell Death

    International Nuclear Information System (INIS)

    Ehrkamp, Anja; Herrmann, Christian; Stoll, Raphael; Heumann, Rolf

    2013-01-01

    One of the most obvious hallmarks of cancer is uncontrolled proliferation of cells partly due to independence of growth factor supply. A major component of mitogenic signaling is Ras, a small GTPase. It was the first identified human protooncogene and is known since more than three decades to promote cellular proliferation and growth. Ras was shown to support growth factor-independent survival during development and to protect from chemical or mechanical lesion-induced neuronal degeneration in postmitotic neurons. In contrast, for specific patho-physiological cases and cellular systems it has been shown that Ras may also promote cell death. Proteins from the Ras association family (Rassf, especially Rassf1 and Rassf5) are tumor suppressors that are activated by Ras-GTP, triggering apoptosis via e.g., activation of mammalian sterile 20-like (MST1) kinase. In contrast to Ras, their expression is suppressed in many types of tumours, which makes Rassf proteins an exciting model for understanding the divergent effects of Ras activity. It seems likely that the outcome of Ras signaling depends on the balance between the activation of its various downstream effectors, thus determining cellular fate towards either proliferation or apoptosis. Ras homologue enriched in brain (Rheb) is a protein from the Ras superfamily that is also known to promote proliferation, growth, and regeneration through the mammalian target of rapamycin (mTor) pathway. However, recent evidences indicate that the Rheb-mTor pathway may switch its function from a pro-growth into a cell death pathway, depending on the cellular situation. In contrast to Ras signaling, for Rheb, the cellular context is likely to modulate the whole Rheb-mTor pathway towards cellular death or survival, respectively

  18. Ras and Rheb Signaling in Survival and Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Ehrkamp, Anja [Molecular Neurobiochemistry, Ruhr University of Bochum, 44780 Bochum (Germany); Herrmann, Christian [Department of Physical Chemistry1, Protein Interaction, Ruhr University of Bochum, 44780 Bochum (Germany); Stoll, Raphael [Biomolecular NMR, Ruhr University of Bochum, 44780 Bochum (Germany); Heumann, Rolf, E-mail: rolf.heumann@rub.de [Molecular Neurobiochemistry, Ruhr University of Bochum, 44780 Bochum (Germany)

    2013-05-28

    One of the most obvious hallmarks of cancer is uncontrolled proliferation of cells partly due to independence of growth factor supply. A major component of mitogenic signaling is Ras, a small GTPase. It was the first identified human protooncogene and is known since more than three decades to promote cellular proliferation and growth. Ras was shown to support growth factor-independent survival during development and to protect from chemical or mechanical lesion-induced neuronal degeneration in postmitotic neurons. In contrast, for specific patho-physiological cases and cellular systems it has been shown that Ras may also promote cell death. Proteins from the Ras association family (Rassf, especially Rassf1 and Rassf5) are tumor suppressors that are activated by Ras-GTP, triggering apoptosis via e.g., activation of mammalian sterile 20-like (MST1) kinase. In contrast to Ras, their expression is suppressed in many types of tumours, which makes Rassf proteins an exciting model for understanding the divergent effects of Ras activity. It seems likely that the outcome of Ras signaling depends on the balance between the activation of its various downstream effectors, thus determining cellular fate towards either proliferation or apoptosis. Ras homologue enriched in brain (Rheb) is a protein from the Ras superfamily that is also known to promote proliferation, growth, and regeneration through the mammalian target of rapamycin (mTor) pathway. However, recent evidences indicate that the Rheb-mTor pathway may switch its function from a pro-growth into a cell death pathway, depending on the cellular situation. In contrast to Ras signaling, for Rheb, the cellular context is likely to modulate the whole Rheb-mTor pathway towards cellular death or survival, respectively.

  19. Reduction of Myeloid-derived Suppressor Cells and Lymphoma Growth by a Natural Triterpenoid

    Science.gov (United States)

    Radwan, Faisal F. Y.; Hossain, Azim; God, Jason M.; Leaphart, Nathan; Elvington, Michelle; Nagarkatti, Mitzi; Tomlinson, Stephen; Haque, Azizul

    2016-01-01

    Lymphoma is a potentially life threatening disease. The goal of this study was to investigate the therapeutic potential of a natural triterpenoid, Ganoderic acid A (GA-A) in controlling lymphoma growth both in vitro and in vivo. Here, we show that GA-A treatment induces caspase-dependent apoptotic cell death characterized by a dose-dependent increase in active caspases 9 and 3, up-regulation of pro-apoptotic BIM and BAX proteins, and a subsequent loss of mitochondrial membrane potential with release of cytochrome c. In addition to GA-A’s anti-growth activity, we show that lower doses of GA-A enhance HLA class II-mediated antigen presentation and CD4+ T cell recognition of lymphoma in vitro. The therapeutic relevance of GA-A treatment was also tested in vivo using the EL4 syngeneic mouse model of metastatic lymphoma. GA-A-treatment significantly prolonged survival of EL4 challenged mice and decreased tumor metastasis to the liver, an outcome accompanied by a marked down-regulation of STAT3 phosphorylation, reduction myeloid-derived suppressor cells (MDSCs), and enhancement of cytotoxic CD8+ T cells in the host. Thus, GA-A not only selectively induces apoptosis in lymphoma cells, but also enhances cell-mediated immune responses by attenuating MDSCs, and elevating Ag presentation and T cell recognition. The demonstrated therapeutic benefit indicates that GA-A is a candidate for future drug design for the treatment of lymphoma. PMID:25142864

  20. The LKB1 tumor suppressor differentially affects anchorage independent growth of HPV positive cervical cancer cell lines

    International Nuclear Information System (INIS)

    Mack, Hildegard I.D.; Munger, Karl

    2013-01-01

    Infection with high-risk human papillomaviruses is causally linked to cervical carcinogenesis. However, most lesions caused by high-risk HPV infections do not progress to cancer. Host cell mutations contribute to malignant progression but the molecular nature of such mutations is unknown. Based on a previous study that reported an association between liver kinase B1 (LKB1) tumor suppressor loss and poor outcome in cervical cancer, we sought to determine the molecular basis for this observation. LKB1-negative cervical and lung cancer cells were reconstituted with wild type or kinase defective LKB1 mutants and we examined the importance of LKB1 catalytic activity in known LKB1-regulated processes including inhibition of cell proliferation and elevated resistance to energy stress. Our studies revealed marked differences in the biological activities of two kinase defective LKB1 mutants in the various cell lines. Thus, our results suggest that LKB1 may be a cell-type specific tumor suppressor. - Highlights: • LKB1 is a tumor suppressor that is linked to Peutz-Jeghers syndrome. • Peutz-Jeghers syndrome patients have a high incidence of cervical cancer. • Cervical cancer is caused by HPV infections. • This study investigates LKB1 tumor suppressor activity in cervical cancer

  1. Comparison of the suppressor cells found in the spleens of 89Sr-treated mice and in normal murine bone marrow

    International Nuclear Information System (INIS)

    Levy, E.M.; Corvese, J.S.; Bennett, M.

    1981-01-01

    Normal murine bone marrow cells and spleen cells of mice treated with 89 Sr both have suppressive activity. These nonspecific suppressor cells inhibit the ability of normal spleen cells to undergo antibody responses in vitro. After being precultured for 24 hr, these cells will also suppress antibody responses in vivo and the responses of normal spleen cells to T and B cell mitogens in vitro. These cells have previously been shown not to be mature T or B lymphocytes or macrophages. Velocity sedimentation and cell-size analysis indicated that both suppressor cells are large (approx. =206 μ 3 ). Mitomycin C treatment eliminated the ability of both suppressor cells to inhibit an in vitro antibody response. In contrast, this treatment did not reduce the ability of the cells to inhibit an in vitro antibody response. In contrast, this treatment did not reduce the ability of the cells to suppress a mitogenic response. Irradiation (1000 R) was also ineffective in eliminating the ability of either cell to suppress a mitogenic response. We conclude that the 2 suppressor cells are closely related if not identical, and we speculate that these cells may function in vivo to suppress immune reactivity in areas of intense hematopoiesis

  2. Nature of the suppressor cells mediating prolonged graft survival after administration of extracted histocompatibility antigen and cyclosporine

    International Nuclear Information System (INIS)

    Yoshimura, N.; Kahan, B.D.

    1985-01-01

    Antigen-specific suppressor T cells are induced by donor histocompatibility antigen extracted from spleen cells with 3M KCl combined with cyclosporine (Ag-CsA). A single i.v. injection of 5 mg 3M-KCl-extracted donor Buffalo (Buf, RT1b) antigen (Ag) combined with a three day course of CsA prolonged renal allograft survival in Wistar-Furth (WFu, RT1u) hosts to a greater extent (MST 26.5 days) than CsA alone (MST 11.8 days). Peripheral blood lymphocytes (PBL) or spleen cells harvested from Ag-CsA-treated recipients ten days after transplantation inhibited the mixed lymphocyte reaction (MLR) between normal responder WFu cells and irradiated Buf cells (55.6% and 64.4% suppression, respectively, P less than 0.025), but not third-party Brown-Norway (BN, RT1n) stimulator cells (13.6% and -18.3% suppression, respectively, NS). The suppressor effect was not mediated by cytolytic cells; there was neither primary nor secondary cytolytic activity against 51 Cr-labeled Con-A blastoid Buf cells. The suppressor cells were neither adherent to plastic dishes nor to nylon-wool columns. PBL irradiated with 800 rads, but not 1500 rads, suppressed the MLR. A single injection of cyclophosphamide (CY, 25 mg/kg) seven days after transplantation abrogated the suppression induced by Ag-CsA treatment. Moreover, PBL from Ag-CsA recipients failed to suppress the MLR, if depleted either of all T cells by treatment with monoclonal antibody (Mab) W3/13 HLK (pan T cells; % suppression -15.8), or of cytotoxic/suppressor cells with Mab OX-8 (-19.3% suppression) together with rabbit antimouse immunoglobulin and complement

  3. Inhibition of tumor growth in syngenetic chimeric mice mediated by a depletion of suppressor T cells

    International Nuclear Information System (INIS)

    Rotter, V.; Trainin, N.

    1975-01-01

    Syngeneic chimeric (lethally irradiated and reconstituted with syngeneic bone marrow cells) mice manifested an increased resistance to the development of Lewis lung carcinoma. In addition, these mice had a higher response to polyvinylpyrrolidone and a reduced reactivity to T mitogens. The present findings suggest that syngeneic chimeric mice lack suppressor T cells shown to regulate the development of Lewis lung tumor and the response to polyvinylpyrrolidone. Other components of the T cell population, such as helper cells responding to sheep red blood cells or cells involved in allograft rejection, assayed in these syngeneic chimeras were found unaffected. The fact that chimeric mice are deficient in a certain suppressor T cell population whereas other T activities are normal suggests the existence of different cell lines within the T cell population. (U.S.)

  4. A virus-sensitive suppressor cell is involved in the regulation of human allospecific T cell-mediated cytotoxicity

    International Nuclear Information System (INIS)

    Muluk, S.C.; Bernstein, D.C.; Shearer, G.M.

    1989-01-01

    The in vitro generation of allospecific CTL by human PBMC was enhanced 4- to 16-fold by sequential plastic and nylon wool adherence, which depleted the PBMC of macrophages and B cells. The enhanced CTL response was suppressed by adding back irradiated, unfractionated PBMC or adherent cells to the depleted cells. This finding suggests that the enhanced CTL response was not simply a consequence of enrichment of T cells, but was instead due to active suppression by radioresistant cells contained in the adherent fraction. Of note is the finding that, unlike the CTL response, the proliferative response to allostimulation was not affected by the removal of adherent cells. The suppressor function could be abrogated by preincubation of irradiated PBMC with influenza A virus before the coculture with depleted cells. Furthermore, costimulation of unfractionated PBMC with influenza A virus and allogeneic stimulators augmented allospecific CTL activity. Thus, in the adherent fraction of human PBMC, there appears to be a native suppressor population that can be functionally inactivated by virus. This result may account for the clinical observation of increased allograft rejection after certain viral infections

  5. Myeloid-Derived Suppressor Cells and Therapeutic Strategies in Cancer

    Directory of Open Access Journals (Sweden)

    Hiroshi Katoh

    2015-01-01

    Full Text Available Development of solid cancer depends on escape from host immunosurveillance. Various types of immune cells contribute to tumor-induced immune suppression, including tumor associated macrophages, regulatory T cells, type 2 NKT cells, and myeloid-derived suppressor cells (MDSCs. Growing body of evidences shows that MDSCs play pivotal roles among these immunosuppressive cells in multiple steps of cancer progression. MDSCs are immature myeloid cells that arise from myeloid progenitor cells and comprise a heterogeneous immune cell population. MDSCs are characterized by the ability to suppress both adaptive and innate immunities mainly through direct inhibition of the cytotoxic functions of T cells and NK cells. In clinical settings, the number of circulating MDSCs is associated with clinical stages and response to treatment in several cancers. Moreover, MDSCs are reported to contribute to chemoresistant phenotype. Collectively, targeting MDSCs could potentially provide a rationale for novel treatment strategies in cancer. This review summarizes recent understandings of MDSCs in cancer and discusses promissing clinical approaches in cancer patients.

  6. Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018

    OpenAIRE

    Galluzzi, L; Vitale, I; Aaronson, Sa; Abrams, Jm; Adam, D; Agostinis, P; Alnemri, Es; Altucci, L; Amelio, I; Andrews, Dw; Annicchiarico-Petruzzelli, M; Antonov, Av; Arama, E; Baehrecke, Eh; Barlev, Na

    2018-01-01

    Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. A...

  7. Myeloid derived suppressor cells as therapeutic target in hematological malignancies

    Directory of Open Access Journals (Sweden)

    Kim eDe Veirman

    2014-12-01

    Full Text Available Myeloid derived suppressor cells (MDSC are a heterogeneous population of immature myeloid cells that accumulate during pathological conditions such as cancer and are associated with a poor clinical outcome. MDSC expansion hampers the host anti-tumor immune response by inhibition of T cell proliferation, cytokine secretion and recruitment of regulatory T cells. In addition, MDSC exert non-immunological functions including the promotion of angiogenesis, tumor invasion and metastasis. Recent years, MDSC are considered as a potential target in solid tumors and hematological malignancies to enhance the effects of currently used immune modulating agents. This review focuses on the characteristics, distribution, functions, cell-cell interactions and targeting of MDSC in hematological malignancies including multiple myeloma, lymphoma and leukemia.

  8. Immunoregulatory changes induced by total lymphoid irradiation. II. Development of thymus-leukemia antigen-positive and -negative suppressor T cells that differ in their regulatory function

    International Nuclear Information System (INIS)

    King, D.P.; Strober, S.

    1981-01-01

    BALB/c mice treated with total lymphoid irradiation (TLI) develop non-antigen-specific suppressor cells of the adoptive secondary antibody response and of the mixed leukocyte reaction. Suppressors of the adoptive anti-DNP response were eliminated by incubation of spleen cells with anti-Thy-1.2 or anti-thymus-leukemia (TL) antiserum and complement before cell transfer. Thymectomy before TLI prevented the appearance of the latter suppressor cells. On the other hand, suppressors of the MLR were eliminated by incubation of spleen cells with anti-Thy-1.2 but not anti-TL antiserum and complement. Thymectomy before TLI did not prevent their subsequent development. Thus, two subpopulations of suppressor T cells that differ in the expression of the TL surface antigen, dependence on the presence of the thymus, and in regulatory functions develop after TLI. The TL+, thymus-dependent cell suppresses the adoptive antibody response, and the TL-, thymus-independent cell suppresses the MLR

  9. Adiponectin deficiency suppresses lymphoma growth in mice by modulating NK cells, CD8 T cells, and myeloid-derived suppressor cells.

    Science.gov (United States)

    Han, Sora; Jeong, Ae Lee; Lee, Sunyi; Park, Jeong Su; Kim, Kwang Dong; Choi, Inpyo; Yoon, Suk Ran; Lee, Myung Sok; Lim, Jong-Seok; Han, Seung Hyun; Yoon, Do Young; Yang, Young

    2013-05-01

    Previously, we found that adiponectin (APN) suppresses IL-2-induced NK cell activation by downregulating the expression of the IFN-γ-inducible TNF-related apoptosis-inducing ligand and Fas ligand. Although the antitumor function of APN has been reported in several types of solid tumors, with few controversial results, no lymphoma studies have been conducted. In this study, we assessed the role of APN in immune cell function, including NK cells, CTLs, and myeloid-derived suppressor cells, in EL4 and B16F10 tumor-bearing APN knockout (KO) mice. We observed attenuated EL4 growth in the APNKO mice. Increased numbers of splenic NK cells and splenic CTLs were identified under naive conditions and EL4-challenged conditions, respectively. In APNKO mice, splenic NK cells showed enhanced cytotoxicity with and without IL-2 stimulation. Additionally, there were decreased levels of myeloid-derived suppressor cell accumulation in the EL4-bearing APNKO mice. Enforced MHC class I expression on B16F10 cells led to attenuated growth of these tumors in APNKO mice. Thus, our results suggest that EL4 regression in APNKO mice is not only due to an enhanced antitumor immune response but also to a high level of MHC class I expression.

  10. Polysaccharide from Lentinus edodes inhibits the immunosuppressive function of myeloid-derived suppressor cells.

    Directory of Open Access Journals (Sweden)

    Hao Wu

    Full Text Available Reversing the function of immune suppressor cells may improve the efficacy of cancer therapy. Here, we have isolated a novel polysaccharide MPSSS (577.2 Kd from Lentinus edodes and examined its effects on differentiation and function of myeloid-derived suppressor cells (MDSCs. MPSSS is composed of glucose (75.0%, galactose (11.7%, mannose (7.8%, and xylose (0.4%. In vivo, it inhibits the growth of McgR32 tumor cells, which is correlated with a reduced percentage of MDSCs in peripheral blood. In vitro, it induces both morphological and biophysical changes in MDSCs. Importantly, MPSSS up-regulates MHC II and F4/80 expression on MDSCs, and reverses their inhibition effect on CD4(+ T cells in a dose-dependent manner. The mechanism study shows that MPSSS may stimulate MDSCs through a MyD88 dependent NF-κB signaling pathway. Together, we demonstrated for the first time that MPSSS stimulates the differentiation of MDSCs and reverses its immunosuppressive functions, shedding new light on developing novel anti-cancer strategies by targeting MDSCs.

  11. Mechanisms of cross-suppression of TNP-specific plaque forming cell responses by TMA-specific first-order T suppressor factor

    Energy Technology Data Exchange (ETDEWEB)

    Jendrisak, G.S.; Bellone, C.J.

    1986-03-05

    The addition of hybridoma-derived phenyltrimethylammonium (TMA)-specific first-order T suppressor factor (TsF/sub 1/) into cultures containing Brucella abortus coupled with the TMA and trinitrophenol haptens (TMA-BA-TNP) results in the cross-suppression of TNP-specific plaque forming cell (PFC) responses. The suppression mediated by TMA-TsF/sub 1/ is dependent on the presence of T cells and specific antigen (TMA). Subculturing of whole spleen cells with TMA-TsF/sub 1/ and specific soluble antigen (TMA-BSA) is able to induce suppressor T cells which cross-suppress the TNP-specific PFC of spleen cell cultures stimulated with TMA-BA-TNP in an antigen (TMA)-dependent manner at the effector phase of the response. The effector acting T suppressor cells (Tse) are nylon wool nonadherent and appears to require whole spleen cells in responding cultures for suppression, suggesting that the target of the Tse is not the TNP-specific B cell. The authors are presently characterizing the mechanisms of cross-suppression by TMA-TsF/sub 1/ and Tse utilizing the described primary in vitro antibody assay.

  12. Cell Death in C. elegans Development.

    Science.gov (United States)

    Malin, Jennifer Zuckerman; Shaham, Shai

    2015-01-01

    Cell death is a common and important feature of animal development, and cell death defects underlie many human disease states. The nematode Caenorhabditis elegans has proven fertile ground for uncovering molecular and cellular processes controlling programmed cell death. A core pathway consisting of the conserved proteins EGL-1/BH3-only, CED-9/BCL2, CED-4/APAF1, and CED-3/caspase promotes most cell death in the nematode, and a conserved set of proteins ensures the engulfment and degradation of dying cells. Multiple regulatory pathways control cell death onset in C. elegans, and many reveal similarities with tumor formation pathways in mammals, supporting the idea that cell death plays key roles in malignant progression. Nonetheless, a number of observations suggest that our understanding of developmental cell death in C. elegans is incomplete. The interaction between dying and engulfing cells seems to be more complex than originally appreciated, and it appears that key aspects of cell death initiation are not fully understood. It has also become apparent that the conserved apoptotic pathway is dispensable for the demise of the C. elegans linker cell, leading to the discovery of a previously unexplored gene program promoting cell death. Here, we review studies that formed the foundation of cell death research in C. elegans and describe new observations that expand, and in some cases remodel, this edifice. We raise the possibility that, in some cells, more than one death program may be needed to ensure cell death fidelity. © 2015 Elsevier Inc. All rights reserved.

  13. Regulation of apoptosis by low serum in cells of different stages of neoplastic progression: enhanced susceptibility after loss of a senescence gene and decreased susceptibility after loss of a tumor suppressor gene.

    Science.gov (United States)

    Preston, G A; Lang, J E; Maronpot, R R; Barrett, J C

    1994-08-01

    A cell culture model system has been used to study the susceptibility of cells to apoptotic cell death during different stages of neoplastic progression. This system consists of normal diploid Syrian hamster embryo (SHE) cells, two preneoplastic cell lines [tumor suppressor stage I (sup +I) and non-tumor suppressor stage II (sup -II)], and hamster tumor cell lines. Stage I preneoplastic cells are nontumorigenic immortal clones that suppress tumorigenicity when hybridized to tumor cells, whereas stage II cells have lost the ability to suppress tumorigenicity in cell hybrids. We refer to these two types of preneoplastic cells as sup +I and sup -II, respectively. Neoplastic progression is generally associated with cellular alterations in growth factor responsiveness. Therefore, to study the regulation of apoptosis in the system described above, cells were cultured in low serum (0.2%) as a means of withdrawing growth factors. In low serum, normal SHE cells were quiescent (labeling index of 0.2%), with little cell death. The sup +I cells showed a relatively low labeling index (1.6%) but, in contrast to the normal cells, died at a high rate (55% cell loss after 48 h) by apoptosis, as evidenced by morphology, DNA fragmentation, and in situ end-labeling of fragmented DNA. The apoptotic cells did not go through a replicative cycle while in low serum, implying that apoptosis was initiated in the G0/G1 phase of the cell cycle. The sup -II cell line showed a high labeling index (40%) after 48 h, but cell growth was balanced by cell death that occurred at approximately the same rate. The cells died, however, predominantly by necrosis. The tumor cell lines continued to proliferate in low serum, with high labeling indices (ranging from 27% to 43%) and a low level of apoptotic or necrotic cell death. To determine the relative ability of these cells to survive in vivo, normal SHE cells, sup +I cells, and sup -II cells were injected s.c. into nude mice. At 5 or 21 days after

  14. Involvement of Arabidopsis Hexokinase1 in Cell Death Mediated by Myo -Inositol Accumulation

    KAUST Repository

    Bruggeman, Quentin

    2015-06-05

    Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. We recently identified the mips1 mutant of Arabidopsis thaliana, which is deficient for the enzyme catalyzing the limiting step of myo-inositol (MI) synthesis. One of the most striking features of mips1 is the light-dependent formation of lesions on leaves due to salicylic acid (SA)-dependent PCD. Here, we identified a suppressor of PCD by screening for mutations that abolish the mips1 cell death phenotype. Our screen identified the hxk1 mutant, mutated in the gene encoding the hexokinase1 (HXK1) enzyme that catalyzes sugar phosphorylation and acts as a genuine glucose sensor. We show that HXK1 is required for lesion formation in mips1 due to alterations in MI content, via SA-dependant signaling. Using two catalytically inactive HXK1 mutants, we also show that hexokinase catalytic activity is necessary for the establishment of lesions in mips1. Gas chromatography-mass spectrometry analyses revealed a restoration of the MI content in mips1 hxk1 that it is due to the activity of the MIPS2 isoform, while MIPS3 is not involved. Our work defines a pathway of HXK1-mediated cell death in plants and demonstrates that two MIPS enzymes act cooperatively under a particular metabolic status, highlighting a novel checkpoint of MI homeostasis in plants. © 2015 American Society of Plant Biologists. All rights reserved.

  15. Effects of intracellular iron overload on cell death and identification of potent cell death inhibitors.

    Science.gov (United States)

    Fang, Shenglin; Yu, Xiaonan; Ding, Haoxuan; Han, Jianan; Feng, Jie

    2018-06-11

    Iron overload causes many diseases, while the underlying etiologies of these diseases are unclear. Cell death processes including apoptosis, necroptosis, cyclophilin D-(CypD)-dependent necrosis and a recently described additional form of regulated cell death called ferroptosis, are dependent on iron or iron-dependent reactive oxygen species (ROS). However, whether the accumulation of intracellular iron itself induces ferroptosis or other forms of cell death is largely elusive. In present study, we study the role of intracellular iron overload itself-induced cell death mechanisms by using ferric ammonium citrate (FAC) and a membrane-permeable Ferric 8-hydroxyquinoline complex (Fe-8HQ) respectively. We show that FAC-induced intracellular iron overload causes ferroptosis. We also identify 3-phosphoinositide-dependent kinase 1 (PDK1) inhibitor GSK2334470 as a potent ferroptosis inhibitor. Whereas, Fe-8HQ-induced intracellular iron overload causes unregulated necrosis, but partially activates PARP-1 dependent parthanatos. Interestingly, we identify many phenolic compounds as potent inhibitors of Fe-8HQ-induced cell death. In conclusion, intracellular iron overload-induced cell death form might be dependent on the intracellular iron accumulation rate, newly identified cell death inhibitors in our study that target ferroptosis and unregulated oxidative cell death represent potential therapeutic strategies against iron overload related diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Cyclophosphamide-induced myeloid-derived suppressor cell population is immunosuppressive but not identical to myeloid-derived suppressor cells induced by growing TC-1 tumors

    Czech Academy of Sciences Publication Activity Database

    Mikyšková, Romana; Indrová, Marie; Polláková, Veronika; Bieblová, Jana; Šímová, Jana; Reiniš, Milan

    2012-01-01

    Roč. 35, č. 5 (2012), s. 374-384 ISSN 1524-9557 R&D Projects: GA ČR(CZ) GPP301/11/P220; GA ČR GA301/09/1024; GA ČR GA301/07/1410 EU Projects: European Commission(XE) 18933 - CLINIGENE Institutional research plan: CEZ:AV0Z50520514 Institutional support: RVO:68378050 Keywords : myeloid-derived suppressor cells * cyclophosphamide * all-trans-retinoic acid * IL-12 * HPV16 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.463, year: 2012

  17. Programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The purpose of this conference to provide a multidisciplinary forum for exchange of state-of-the-art information on the role programmed cell death plays in normal development and homeostasis of many organisms. This volume contains abstracts of papers in the following areas: invertebrate development; immunology/neurology; bcl-2 family; biochemistry; programmed cell death in viruses; oncogenesis; vertebrate development; and diseases.

  18. Pathophysiological mechanisms of death resistance in colorectal carcinoma.

    Science.gov (United States)

    Huang, Ching-Ying; Yu, Linda Chia-Hui

    2015-11-07

    Colon cancers develop adaptive mechanisms to survive under extreme conditions and display hallmarks of unlimited proliferation and resistance to cell death. The deregulation of cell death is a key factor that contributes to chemoresistance in tumors. In a physiological context, balance between cell proliferation and death, and protection against cell damage are fundamental processes for maintaining gut epithelial homeostasis. The mechanisms underlying anti-death cytoprotection and tumor resistance often bear common pathways, and although distinguishing them would be a challenge, it would also provide an opportunity to develop advanced anti-cancer therapeutics. This review will outline cell death pathways (i.e., apoptosis, necrosis, and necroptosis), and discuss cytoprotective strategies in normal intestinal epithelium and death resistance mechanisms of colon tumor. In colorectal cancers, the intracellular mechanisms of death resistance include the direct alteration of apoptotic and necroptotic machinery and the upstream events modulating death effectors such as tumor suppressor gene inactivation and pro-survival signaling pathways. The autocrine, paracrine and exogenous factors within a tumor microenvironment can also instigate resistance against apoptotic and necroptotic cell death in colon cancers through changes in receptor signaling or transporter uptake. The roles of cyclooxygenase-2/prostaglandin E2, growth factors, glucose, and bacterial lipopolysaccharides in colorectal cancer will be highlighted. Targeting anti-death pathways in the colon cancer tissue might be a promising approach outside of anti-proliferation and anti-angiogenesis strategies for developing novel drugs to treat refractory tumors.

  19. Myeloid-derived suppressor cells in breast cancer.

    Science.gov (United States)

    Markowitz, Joseph; Wesolowski, Robert; Papenfuss, Tracey; Brooks, Taylor R; Carson, William E

    2013-07-01

    Myeloid-derived suppressor cells (MDSCs) are a population of immature myeloid cells defined by their suppressive actions on immune cells such as T cells, dendritic cells, and natural killer cells. MDSCs typically are positive for the markers CD33 and CD11b but express low levels of HLADR in humans. In mice, MDSCs are typically positive for both CD11b and Gr1. These cells exert their suppressive activity on the immune system via the production of reactive oxygen species, arginase, and cytokines. These factors subsequently inhibit the activity of multiple protein targets such as the T cell receptor, STAT1, and indoleamine-pyrrole 2,3-dioxygenase. The numbers of MDSCs tend to increase with cancer burden while inhibiting MDSCs improves disease outcome in murine models. MDSCs also inhibit immune cancer therapeutics. In light of the poor prognosis of metastatic breast cancer in women and the correlation of increasing levels of MDSCs with increasing disease burden, the purposes of this review are to (1) discuss why MDSCs may be important in breast cancer, (2) describe model systems used to study MDSCs in vitro and in vivo, (3) discuss mechanisms involved in MDSC induction/function in breast cancer, and (4) present pre-clinical and clinical studies that explore modulation of the MDSC-immune system interaction in breast cancer. MDSCs inhibit the host immune response in breast cancer patients and diminishing MDSC actions may improve therapeutic outcomes.

  20. Transcriptional Inhibition of the Human Papilloma Virus Reactivates Tumor Suppressor p53 in Cervical Carcinoma Cells

    Science.gov (United States)

    Kochetkov, D. V.; Ilyinskaya, G. V.; Komarov, P. G.; Strom, E.; Agapova, L. S.; Ivanov, A. V.; Budanov, A. V.; Frolova, E. I.; Chumakov, P. M.

    2009-01-01

    Inactivation of tumor suppressor p53 accompanies the majority of human malignancies. Restoration of p53 function causes death of tumor cells and is potentially suitable for gene therapy of cancer. In cervical carcinoma, human papilloma virus (HPV) E6 facilitates proteasomal degradation of p53. Hence, a possible approach to p53 reactivation is the use of small molecules suppressing the function of viral proteins. HeLa cervical carcinoma cells (HPV-18) with a reporter construct containing the b-galactosidase gene under the control of a p53-responsive promoter were used as a test system to screen a library of small molecules for restoration of the transcriptional activity of p53. The effect of the two most active compounds was studied with cell lines differing in the state of p53-dependent signaling pathways. The compounds each specifically activated p53 in cells expressing HPV-18 and, to a lesser extent, HPV-16 and exerted no effect on control p53-negative cells or cells with the intact p53-dependent pathways. Activation of p53 in cervical carcinoma cells was accompanied by induction of p53-dependent CDKN1 (p21), inhibition of cell proliferation, and induction of apoptosis. In addition, the two compounds dramatically decreased transcription of the HPV genome, which was assumed to cause p53 reactivation. The compounds were low-toxic for normal cells and can be considered as prototypes of new anticancer drugs. PMID:17685229

  1. Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018

    NARCIS (Netherlands)

    Galluzzi, Lorenzo; Vitale, Ilio; Aaronson, Stuart A.; Abrams, John M.; Adam, Dieter; Agostinis, Patrizia; Alnemri, Emad S.; Altucci, Lucia; Amelio, Ivano; Andrews, David W.; Annicchiarico-Petruzzelli, Margherita; Antonov, Alexey V.; Arama, Eli; Baehrecke, Eric H.; Barlev, Nickolai A.; Bazan, Nicolas G.; Bernassola, Francesca; Bertrand, Mathieu J. M.; Bianchi, Katiuscia; Blagosklonny, Mikhail V.; Blomgren, Klas; Borner, Christoph; Boya, Patricia; Brenner, Catherine; Campanella, Michelangelo; Candi, Eleonora; Carmona-Gutierrez, Didac; Cecconi, Francesco; Chan, Francis K.-M.; Chandel, Navdeep S.; Cheng, Emily H.; Chipuk, Jerry E.; Cidlowski, John A.; Ciechanover, Aaron; Cohen, Gerald M.; Conrad, Marcus; Cubillos-Ruiz, Juan R.; Czabotar, Peter E.; D'Angiolella, Vincenzo; Dawson, Ted M.; Dawson, Valina L.; de Laurenzi, Vincenzo; de Maria, Ruggero; Debatin, Klaus-Michael; DeBerardinis, Ralph J.; Deshmukh, Mohanish; Di Daniele, Nicola; Di Virgilio, Francesco; Dixit, Vishva M.; Dixon, Scott J.; Duckett, Colin S.; Dynlacht, Brian D.; El-Deiry, Wafik S.; Elrod, John W.; Fimia, Gian Maria; Fulda, Simone; García-Sáez, Ana J.; Garg, Abhishek D.; Garrido, Carmen; Gavathiotis, Evripidis; Golstein, Pierre; Gottlieb, Eyal; Green, Douglas R.; Greene, Lloyd A.; Gronemeyer, Hinrich; Gross, Atan; Hajnoczky, Gyorgy; Hardwick, J. Marie; Harris, Isaac S.; Hengartner, Michael O.; Hetz, Claudio; Ichijo, Hidenori; Jäättelä, Marja; Joseph, Bertrand; Jost, Philipp J.; Juin, Philippe P.; Kaiser, William J.; Karin, Michael; Kaufmann, Thomas; Kepp, Oliver; Kimchi, Adi; Kitsis, Richard N.; Klionsky, Daniel J.; Knight, Richard A.; Kumar, Sharad; Lee, Sam W.; Lemasters, John J.; Levine, Beth; Linkermann, Andreas; Lipton, Stuart A.; Lockshin, Richard A.; López-Otín, Carlos; Lowe, Scott W.; Luedde, Tom; Lugli, Enrico; MacFarlane, Marion; Madeo, Frank; Malewicz, Michal; Malorni, Walter; Manic, Gwenola; Marine, Jean-Christophe; Martin, Seamus J.; Martinou, Jean-Claude; Medema, Jan Paul; Mehlen, Patrick; Meier, Pascal; Melino, Sonia; Miao, Edward A.; Molkentin, Jeffery D.; Moll, Ute M.; Muñoz-Pinedo, Cristina; Nagata, Shigekazu; Nuñez, Gabriel; Oberst, Andrew; Oren, Moshe; Overholtzer, Michael; Pagano, Michele; Panaretakis, Theocharis; Pasparakis, Manolis; Penninger, Josef M.; Pereira, David M.; Pervaiz, Shazib; Peter, Marcus E.; Piacentini, Mauro; Pinton, Paolo; Prehn, Jochen H. M.; Puthalakath, Hamsa; Rabinovich, Gabriel A.; Rehm, Markus; Rizzuto, Rosario; Rodrigues, Cecilia M. P.; Rubinsztein, David C.; Rudel, Thomas; Ryan, Kevin M.; Sayan, Emre; Scorrano, Luca; Shao, Feng; Shi, Yufang; Silke, John; Simon, Hans-Uwe; Sistigu, Antonella; Stockwell, Brent R.; Strasser, Andreas; Szabadkai, Gyorgy; Tait, Stephen W. G.; Tang, Daolin; Tavernarakis, Nektarios; Thorburn, Andrew; Tsujimoto, Yoshihide; Turk, Boris; Vanden Berghe, Tom; Vandenabeele, Peter; Vander Heiden, Matthew G.; Villunger, Andreas; Virgin, Herbert W.; Vousden, Karen H.; Vucic, Domagoj; Wagner, Erwin F.; Walczak, Henning; Wallach, David; Wang, Ying; Wells, James A.; Wood, Will; Yuan, Junying; Zakeri, Zahra; Zhivotovsky, Boris; Zitvogel, Laurence; Melino, Gerry; Kroemer, Guido

    2018-01-01

    Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell

  2. Nonthermal-plasma-mediated animal cell death

    Science.gov (United States)

    Kim, Wanil; Woo, Kyung-Chul; Kim, Gyoo-Cheon; Kim, Kyong-Tai

    2011-01-01

    Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood.

  3. Nonthermal-plasma-mediated animal cell death

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wanil; Woo, Kyung-Chul; Kim, Kyong-Tai [Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, San 31, Hyoja Dong, Pohang 790-784 (Korea, Republic of); Kim, Gyoo-Cheon, E-mail: ktk@postech.ac.kr [Department of Oral Anatomy and Cell Biology, School of Dentistry, Pusan National University, Yangsan 626-810 (Korea, Republic of)

    2011-01-12

    Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood. (topical review)

  4. Nonthermal-plasma-mediated animal cell death

    International Nuclear Information System (INIS)

    Kim, Wanil; Woo, Kyung-Chul; Kim, Kyong-Tai; Kim, Gyoo-Cheon

    2011-01-01

    Animal cell death comprising necrosis and apoptosis occurred in a well-regulated manner upon specific stimuli. The physiological meanings and detailed molecular mechanisms of cell death have been continuously investigated over several decades. Necrotic cell death has typical morphological changes, such as cell swelling and cell lysis followed by DNA degradation, whereas apoptosis shows blebbing formation and regular DNA fragmentation. Cell death is usually adopted to terminate cancer cells in vivo. The current strategies against tumour are based on the induction of cell death by adopting various methods, including radiotherapy and chemotherapeutics. Among these, radiotherapy is the most frequently used treatment method, but it still has obvious limitations. Recent studies have suggested that the use of nonthermal air plasma can be a prominent method for inducing cancer cell death. Plasma-irradiated cells showed the loss of genomic integrity, mitochondrial dysfunction, plasma membrane damage, etc. Tumour elimination with plasma irradiation is an emerging concept in cancer therapy and can be accelerated by targeting certain tumour-specific proteins with gold nanoparticles. Here, some recent developments are described so that the mechanisms related to plasma-mediated cell death and its perspectives in cancer treatment can be understood. (topical review)

  5. Alternative Cell Death Pathways and Cell Metabolism

    Directory of Open Access Journals (Sweden)

    Simone Fulda

    2013-01-01

    Full Text Available While necroptosis has for long been viewed as an accidental mode of cell death triggered by physical or chemical damage, it has become clear over the last years that necroptosis can also represent a programmed form of cell death in mammalian cells. Key discoveries in the field of cell death research, including the identification of critical components of the necroptotic machinery, led to a revised concept of cell death signaling programs. Several regulatory check and balances are in place in order to ensure that necroptosis is tightly controlled according to environmental cues and cellular needs. This network of regulatory mechanisms includes metabolic pathways, especially those linked to mitochondrial signaling events. A better understanding of these signal transduction mechanisms will likely contribute to open new avenues to exploit our knowledge on the regulation of necroptosis signaling for therapeutic application in the treatment of human diseases.

  6. Estrogen receptor beta, a possible tumor suppressor involved in ovarian carcinogenesis

    Science.gov (United States)

    Lazennec, Gwendal

    2006-01-01

    Ovarian cancer is one of the leading cause of death from gynecological tumors in women. Several lines of evidence suggest that estrogens may play an important role in ovarian carcinogenesis, through their receptors, ERα and ERβ. Interestingly, malignant ovarian tumors originating from epithelial surface constitute about 90% of ovarian cancers and expressed low levels of ERβ, compared to normal tissues. In addition, restoration of ERβ in ovarian cancer cells, leads to strong inhibition of their proliferation and invasion, while apoptosis is enhanced. In this manuscript, recent data suggesting a possible tumor-suppressor role for ERβ in ovarian carcinogenesis are discussed. PMID:16399219

  7. Glutathione in Cancer Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Angel L. [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain); Mena, Salvador [Green Molecular SL, Pol. Ind. La Coma-Parc Cientific, 46190 Paterna, Valencia (Spain); Estrela, Jose M., E-mail: jose.m.estrela@uv.es [Department of Physiology, Faculty of Medicine and Odontology, University of Valencia, 17 Av. Blasco Ibanez, 46010 Valencia (Spain)

    2011-03-11

    Glutathione (L-γ-glutamyl-L-cysteinyl-glycine; GSH) in cancer cells is particularly relevant in the regulation of carcinogenic mechanisms; sensitivity against cytotoxic drugs, ionizing radiations, and some cytokines; DNA synthesis; and cell proliferation and death. The intracellular thiol redox state (controlled by GSH) is one of the endogenous effectors involved in regulating the mitochondrial permeability transition pore complex and, in consequence, thiol oxidation can be a causal factor in the mitochondrion-based mechanism that leads to cell death. Nevertheless GSH depletion is a common feature not only of apoptosis but also of other types of cell death. Indeed rates of GSH synthesis and fluxes regulate its levels in cellular compartments, and potentially influence switches among different mechanisms of death. How changes in gene expression, post-translational modifications of proteins, and signaling cascades are implicated will be discussed. Furthermore, this review will finally analyze whether GSH depletion may facilitate cancer cell death under in vivo conditions, and how this can be applied to cancer therapy.

  8. Cell of Origin and Cancer Stem Cells in Tumor Suppressor Mouse Models of Glioblastoma.

    Science.gov (United States)

    Alcantara Llaguno, Sheila R; Xie, Xuanhua; Parada, Luis F

    2016-01-01

    The cellular origins and the mechanisms of progression, maintenance of tumorigenicity, and therapeutic resistance are central questions in the glioblastoma multiforme (GBM) field. Using tumor suppressor mouse models, our group recently reported two independent populations of adult GBM-initiating central nervous system progenitors. We found different functional and molecular subtypes depending on the tumor-initiating cell lineage, indicating that the cell of origin is a driver of GBM subtype diversity. Using an in vivo model, we also showed that GBM cancer stem cells (CSCs) or glioma stem cells (GSCs) contribute to resistance to chemotherapeutic agents and that genetic ablation of GSCs leads to a delay in tumor progression. These studies are consistent with the cell of origin and CSCs as critical regulators of the pathogenesis of GBM. © 2016 Alcantara Llaguno et al; Published by Cold Spring Harbor Laboratory Press.

  9. Polycation-mediated integrated cell death processes

    DEFF Research Database (Denmark)

    Parhamifar, Ladan; Andersen, Helene; Wu, Linping

    2014-01-01

    standard. PEIs are highly efficient transfectants, but depending on their architecture and size they induce cytotoxicity through different modes of cell death pathways. Here, we briefly review dynamic and integrated cell death processes and pathways, and discuss considerations in cell death assay design...

  10. Targeting Myeloid-Derived Suppressor Cells to Bypass Tumor-Induced Immunosuppression

    Directory of Open Access Journals (Sweden)

    Viktor Fleming

    2018-03-01

    Full Text Available The immune system has many sophisticated mechanisms to balance an extensive immune response. Distinct immunosuppressive cells could protect from excessive tissue damage and autoimmune disorders. Tumor cells take an advantage of those immunosuppressive mechanisms and establish a strongly immunosuppressive tumor microenvironment (TME, which inhibits antitumor immune responses, supporting the disease progression. Myeloid-derived suppressor cells (MDSC play a crucial role in this immunosuppressive TME. Those cells represent a heterogeneous population of immature myeloid cells with a strong immunosuppressive potential. They inhibit an antitumor reactivity of T cells and NK cells. Furthermore, they promote angiogenesis, establish pre-metastatic niches, and recruit other immunosuppressive cells such as regulatory T cells. Accumulating evidences demonstrated that the enrichment and activation of MDSC correlated with tumor progression, recurrence, and negative clinical outcome. In the last few years, various preclinical studies and clinical trials targeting MDSC showed promising results. In this review, we discuss different therapeutic approaches on MDSC targeting to overcome immunosuppressive TME and enhance the efficiency of current tumor immunotherapies.

  11. Antihelminthic drug niclosamide inhibits CIP2A and reactivates tumor suppressor protein phosphatase 2A in non-small cell lung cancer cells.

    Science.gov (United States)

    Kim, Myeong-Ok; Choe, Min Ho; Yoon, Yi Na; Ahn, Jiyeon; Yoo, Minjin; Jung, Kwan-Young; An, Sungkwan; Hwang, Sang-Gu; Oh, Jeong Su; Kim, Jae-Sung

    2017-11-15

    Protein phosphatase 2A (PP2A) is a critical tumor suppressor complex responsible for the inactivation of various oncogenes. Recently, PP2A reactivation has emerged asan anticancer strategy. Cancerous inhibitor of protein phosphatase 2A (CIP2A), an endogenous inhibitor of PP2A, is upregulated in many cancer cells, including non-small cell lung cancer (NSCLC) cells. We demonstrated that the antihelminthic drug niclosamide inhibited the expression of CIP2A and reactivated the tumor suppressor PP2A in NSCLC cells. We performed a drug-repurposing screen and identified niclosamide asa CIP2A suppressor in NSCLC cells. Niclosamide inhibited cell proliferation, colony formation, and tumor sphere formation, and induced mitochondrial dysfunction through increased mitochondrial ROS production in NSCLC cells; however, these effects were rescued by CIP2A overexpression, which indicated that the antitumor activity of niclosamide was dependent on CIP2A. We found that niclosamide increased PP2A activity through CIP2A inhibition, which reduced the phosphorylation of several oncogenic proteins. Moreover, we found that a niclosamide analog inhibited CIP2A expression and increased PP2A activity in several types of NSCLC cells. Finally, we showed that other well-known PP2A activators, including forskolin and FTY720, did not inhibit CIP2A and that their activities were not dependent on CIP2A. Collectively, our data suggested that niclosamide effectively suppressed CIP2A expression and subsequently activated PP2A in NSCLC cells. This provided strong evidence for the potential use of niclosamide asa PP2A-activating drug in the clinical treatment of NSCLC. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Tumor suppressors: enhancers or suppressors of regeneration?

    Science.gov (United States)

    Pomerantz, Jason H.; Blau, Helen M.

    2013-01-01

    Tumor suppressors are so named because cancers occur in their absence, but these genes also have important functions in development, metabolism and tissue homeostasis. Here, we discuss known and potential functions of tumor suppressor genes during tissue regeneration, focusing on the evolutionarily conserved tumor suppressors pRb1, p53, Pten and Hippo. We propose that their activity is essential for tissue regeneration. This is in contrast to suggestions that tumor suppression is a trade-off for regenerative capacity. We also hypothesize that certain aspects of tumor suppressor pathways inhibit regenerative processes in mammals, and that transient targeted modification of these pathways could be fruitfully exploited to enhance processes that are important to regenerative medicine. PMID:23715544

  13. Changes in helper and suppressor T lymphocytes following radiotherapy for breast cancer

    International Nuclear Information System (INIS)

    Newman, G.H.; Rees, G.J.G.; Jones, R.S.J.; Grove, E.A.; Preece, A.W.

    1987-01-01

    Changes in total lymphocyte, T lymphocyte, T helper and T suppressor lymphocyte numbers were studied in 22 patients with breast cancer before and after radiotherapy. T lymphocyte subsets were measured using monoclonal antibodies and fluorescence microscopy. After treatment the total lymphocyte count fell significantly and was still reduced 9 months later, but the proportion of cells labelled as T lymphocytes was unchanged during this period. The helper-suppressor ratio, which was within the normal range before radiotherapy, was significantly reduced at 3 months and 9 months after. Following treatment both T helper and T suppressor cell numbers were significantly reduced. T helper cell numbers remained reduced throughout the study period but T suppressor cell numbers showed a recovery to normal values 9 months after radiotherapy. (author)

  14. Grape seed proanthocyanidins reactivate silenced tumor suppressor genes in human skin cancer cells by targeting epigenetic regulators

    International Nuclear Information System (INIS)

    Vaid, Mudit; Prasad, Ram; Singh, Tripti; Jones, Virginia; Katiyar, Santosh K.

    2012-01-01

    Grape seed proanthocyanidins (GSPs) have been shown to have anti-skin carcinogenic effects in in vitro and in vivo models. However, the precise epigenetic molecular mechanisms remain unexplored. This study was designed to investigate whether GSPs reactivate silenced tumor suppressor genes following epigenetic modifications in skin cancer cells. For this purpose, A431 and SCC13 human squamous cell carcinoma cell lines were used as in vitro models. The effects of GSPs on DNA methylation, histone modifications and tumor suppressor gene expressions were studied in these cell lines using enzyme activity assays, western blotting, dot-blot analysis and real-time polymerase chain reaction (RT-PCR). We found that treatment of A431 and SCC13 cells with GSPs decreased the levels of: (i) global DNA methylation, (ii) 5-methylcytosine, (iii) DNA methyltransferase (DNMT) activity and (iv) messenger RNA (mRNA) and protein levels of DNMT1, DNMT3a and DNMT3b in these cells. Similar effects were noted when these cancer cells were treated identically with 5-aza-2′-deoxycytidine, an inhibitor of DNA methylation. GSPs decreased histone deacetylase activity, increased levels of acetylated lysines 9 and 14 on histone H3 (H3-Lys 9 and 14) and acetylated lysines 5, 12 and 16 on histone H4, and reduced the levels of methylated H3-Lys 9. Further, GSP treatment resulted in re-expression of the mRNA and proteins of silenced tumor suppressor genes, RASSF1A, p16 INK4a and Cip1/p21. Together, this study provides a new insight into the epigenetic mechanisms of GSPs and may have significant implications for epigenetic therapy in the treatment/prevention of skin cancers in humans. -- Highlights: ►Epigenetic modulations have been shown to have a role in cancer risk. ►Proanthocyanidins decrease the levels of DNA methylation and histone deacetylation. ►Proanthocyanidins inhibit histone deacetylase activity in skin cancer cells. ►Proanthocyanidins reactivate tumor suppressor genes in skin

  15. NDRG2 is a candidate tumor-suppressor for oral squamous-cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Hiroshi; Kondo, Yuudai [Division of Oral and Maxillofacial Surgery, Medicine of Sensory and Motor Organs, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Division of Tumor and Cellular Biochemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Nakahata, Shingo; Hamasaki, Makoto [Division of Tumor and Cellular Biochemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Sakoda, Sumio [Division of Oral and Maxillofacial Surgery, Medicine of Sensory and Motor Organs, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan); Morishita, Kazuhiro, E-mail: kmorishi@med.miyazaki-u.ac.jp [Division of Tumor and Cellular Biochemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692 (Japan)

    2010-01-22

    Oral cancer is one of the most common cancers worldwide, and squamous-cell carcinoma (OSCC) is the most common phenotype of oral cancer. Although patients with OSCC have poor survival rates and a high incidence of metastasis, the molecular mechanisms of OSCC development have not yet been elucidated. This study investigated whether N-myc downstream-regulated gene 2 (NDRG2) contributes to the carcinogenesis of OSCC, as NDRG2 is reported to be a candidate tumor-suppressor gene in a wide variety of cancers. The down-regulation of NDRG2 mRNA, which was dependent on promoter methylation, was seen in the majority of OSCC cases and in several cases of precancerous leukoplakia with dysplasia. Induction of NDRG2 expression in an HSC-3/OSCC cell line significantly inhibited cell proliferation and decreased colony formation ability on soft agar. The majority of OSCC cell lines showed an activation of PI3K/Akt signaling, and enforced expression of NDRG2 in HSC-3 cells decreased the level of phosphorylated Akt at Serine 473 (p-Akt). Immunohistochemical p-Akt staining was detected in 56.5% of the OSCC tumors, and 80.4% of the tumors were negative for NDRG2 staining. Moreover, positive p-Akt staining was inversely correlated with decreased NDRG2 expression in OSCC tumors with moderate to poor differentiation (p < 0.005). Therefore, NDRG2 is a candidate tumor-suppressor gene for OSCC development and probably contributes to the tumorigenesis of OSCC partly via the modulation of Akt signaling.

  16. Modulation of allogeneic stimulation in man. I. Characterization of an in vitro induced suppressor macrophage population

    International Nuclear Information System (INIS)

    Stux, S.V.; Dubey, D.P.; Yunis, E.J.

    1981-01-01

    Cultured human peripheral blood mononuclear cells suppressed the allogeneic response of fresh autologous lymphocytes. This suppressor activity developed gradually over a period of one week. The cells primarily responsible for this effect were enriched by Ficoll density gradient centrifugation. It was found that the suppressor cell is a large, low density nylon wool adherent, radioresistant, phagocytic, and nonspecific esterase positive mononuclear cell. Moreover, these cells did not form E rosettes and were Fc positive. Electron microscopy confirmed that suppressor cells were macrophage like. Suppressor activity was not due to cytotoxicity, crowding, or steric hinderance by the cultured cells. The suppressor macrophage population did not appear to inhibit the allogeneic response via prostaglandin or arginase release, or interfere with the tritiated thymidine uptake by release of endogenous thymidine. The above system is viewed as an in vitro model of immune regulation by suppressor macrophages, in the context of allogeneic response

  17. Improved crystallization and diffraction of caffeine-induced death suppressor protein 1 (Cid1)

    Energy Technology Data Exchange (ETDEWEB)

    Yates, Luke A., E-mail: luke@strubi.ox.ac.uk; Durrant, Benjamin P.; Barber, Michael; Harlos, Karl [University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom); Fleurdépine, Sophie; Norbury, Chris J. [University of Oxford, South Parks Road, Oxford OX1 3RE (United Kingdom); Gilbert, Robert J. C., E-mail: luke@strubi.ox.ac.uk [University of Oxford, Roosevelt Drive, Oxford OX3 7BN (United Kingdom)

    2015-02-21

    The use of truncation and RNA-binding mutations of caffeine induced death suppressor protein 1 (Cid1) as a means to enhance crystallogenesis leading to an improvement of X-ray diffraction resolution by 1.5 Å is reported. The post-transcriptional addition of uridines to the 3′-end of RNAs is an important regulatory process that is critical for coding and noncoding RNA stability. In fission yeast and metazoans this untemplated 3′-uridylylation is catalysed by a single family of terminal uridylyltransferases (TUTs) whose members are adapted to specific RNA targets. In Schizosaccharomyces pombe the TUT Cid1 is responsible for the uridylylation of polyadenylated mRNAs, targeting them for destruction. In metazoans, the Cid1 orthologues ZCCHC6 and ZCCHC11 uridylate histone mRNAs, targeting them for degradation, but also uridylate microRNAs, altering their maturation. Cid1 has been studied as a model TUT that has provided insights into the larger and more complex metazoan enzyme system. In this paper, two strategies are described that led to improvements both in the crystallogenesis of Cid1 and in the resolution of diffraction by ∼1.5 Å. These advances have allowed high-resolution crystallo@@graphic studies of this TUT system to be initiated.

  18. Improved crystallization and diffraction of caffeine-induced death suppressor protein 1 (Cid1)

    International Nuclear Information System (INIS)

    Yates, Luke A.; Durrant, Benjamin P.; Barber, Michael; Harlos, Karl; Fleurdépine, Sophie; Norbury, Chris J.; Gilbert, Robert J. C.

    2015-01-01

    The use of truncation and RNA-binding mutations of caffeine induced death suppressor protein 1 (Cid1) as a means to enhance crystallogenesis leading to an improvement of X-ray diffraction resolution by 1.5 Å is reported. The post-transcriptional addition of uridines to the 3′-end of RNAs is an important regulatory process that is critical for coding and noncoding RNA stability. In fission yeast and metazoans this untemplated 3′-uridylylation is catalysed by a single family of terminal uridylyltransferases (TUTs) whose members are adapted to specific RNA targets. In Schizosaccharomyces pombe the TUT Cid1 is responsible for the uridylylation of polyadenylated mRNAs, targeting them for destruction. In metazoans, the Cid1 orthologues ZCCHC6 and ZCCHC11 uridylate histone mRNAs, targeting them for degradation, but also uridylate microRNAs, altering their maturation. Cid1 has been studied as a model TUT that has provided insights into the larger and more complex metazoan enzyme system. In this paper, two strategies are described that led to improvements both in the crystallogenesis of Cid1 and in the resolution of diffraction by ∼1.5 Å. These advances have allowed high-resolution crystallo@@graphic studies of this TUT system to be initiated

  19. Silver nanoparticles of different sizes induce a mixed type of programmed cell death in human pancreatic ductal adenocarcinoma

    Science.gov (United States)

    Zielinska, Ewelina; Zauszkiewicz-Pawlak, Agata; Wojcik, Michal; Inkielewicz-Stepniak, Iwona

    2018-01-01

    Pancreatic ductal adenocarcinoma, with the high resistance to chemotherapeutic agents, remains the fourth leading cause of cancer-death in the world. Due to the wide range of biological activity and unique properties, silver nanoparticles (AgNPs) are indicated as agents with potential to overcome barriers involved in chemotherapy failure. Therefore, in our study we decided to assess the ability of AgNPs to kill pancreatic cancer cells, and then to identify the molecular mechanism underlying this effect. Moreover, we evaluated the cytotoxicity of AgNPs against non-tumor cell of the same tissue (hTERT-HPNE cells) for comparison. Our results indicated that AgNPs with size of 2.6 and 18 nm decreased viability, proliferation and caused death of pancreatic cancer cells in a size- and concentration-dependent manner. Ultrastructural analysis identified that cellular uptake of AgNPs resulted in apoptosis, autophagy, necroptosis and mitotic catastrophe. These alterations were associated with increased pro-apoptotic protein Bax and decreased level of anti-apoptotic protein Bcl-2. Moreover, AgNPs significantly elevated the level of tumor suppressor p53 protein as well as necroptosis- and autophagy-related proteins: RIP-1, RIP-3, MLKL and LC3-II, respectively. In addition, we found that PANC-1 cells were more vulnerable to AgNPs-induced cytotoxicity compared to pancreatic non-tumor cells. In conclusion, AgNPs by inducing mixed type of programmed cell death in PANC-1 cells, could provide a new therapeutic strategy to overcome chemoresistance in one of the deadliest human cancer. PMID:29435134

  20. Non-cell autonomous or secretory tumor suppression.

    Science.gov (United States)

    Chua, Christelle En Lin; Chan, Shu Ning; Tang, Bor Luen

    2014-10-01

    Many malignancies result from deletions or loss-of-function mutations in one or more tumor suppressor genes, the products of which curb unrestrained growth or induce cell death in those with dysregulated proliferative capacities. Most tumor suppressors act in a cell autonomous manner, and only very few proteins are shown to exert a non-cell autonomous tumor suppressor function on other cells. Examples of these include members of the secreted frizzled-related protein (SFRP) family and the secreted protein acidic and rich in cysteine (SPARC)-related proteins. Very recent findings have, however, considerably expanded our appreciation of non-cell autonomous tumor suppressor functions. Broadly, this may occur in two ways. Intracellular tumor suppressor proteins within cells could in principle inhibit aberrant growth of neighboring cells by conditioning an antitumor microenvironment through secreted factors. This is demonstrated by an apparent non-cell autonomous tumor suppressing property of p53. On the other hand, a tumor suppressor produced by a cell may be secreted extracellularly, and taken up by another cell with its activity intact. Intriguingly, this has been recently shown to occur for the phosphatase and tensin homolog (PTEN) by both conventional and unconventional modes of secretion. These recent findings would aid the development of therapeutic strategies that seek to reinstate tumor suppression activity in therapeutically recalcitrant tumor cells, which have lost it in the first place. © 2014 Wiley Periodicals, Inc.

  1. Activated T cells sustain myeloid-derived suppressor cell-mediated immune suppression

    Science.gov (United States)

    Damuzzo, Vera; Francescato, Samuela; Pozzuoli, Assunta; Berizzi, Antonio; Mocellin, Simone; Rossi, Carlo Riccardo; Bronte, Vincenzo; Mandruzzato, Susanna

    2016-01-01

    The expansion of myeloid derived suppressor cells (MDSCs), a suppressive population able to hamper the immune response against cancer, correlates with tumor progression and overall survival in several cancer types. We have previously shown that MDSCs can be induced in vitro from precursors present in the bone marrow and observed that these cells are able to actively proliferate in the presence of activated T cells, whose activation level is critical to drive the suppressive activity of MDSCs. Here we investigated at molecular level the mechanisms involved in the interplay between MDSCs and activated T cells. We found that activated T cells secrete IL-10 following interaction with MDSCs which, in turn, activates STAT3 phosphorylation on MDSCs then leading to B7-H1 expression. We also demonstrated that B7-H1+ MDSCs are responsible for immune suppression through a mechanism involving ARG-1 and IDO expression. Finally, we show that the expression of ligands B7-H1 and MHC class II both on in vitro-induced MDSCs and on MDSCs in the tumor microenvironment of cancer patients is paralleled by an increased expression of their respective receptors PD-1 and LAG-3 on T cells, two inhibitory molecules associated with T cell dysfunction. These findings highlight key molecules and interactions responsible for the extensive cross-talk between MDSCs and activated T cells that are at the basis of immune suppression. PMID:26700461

  2. SIRT3: Oncogene and Tumor Suppressor in Cancer

    Directory of Open Access Journals (Sweden)

    Margalida Torrens-Mas

    2017-07-01

    Full Text Available Sirtuin 3 (SIRT3, the major deacetylase in mitochondria, plays a crucial role in modulating oxygen reactive species (ROS and limiting the oxidative damage in cellular components. SIRT3 targets different enzymes which regulate mitochondrial metabolism and participate in ROS detoxification, such as the complexes of the respiratory chain, the isocitrate dehydrogenase, or the manganese superoxide dismutase. Thus, SIRT3 activity is essential in maintaining mitochondria homeostasis and has recently received great attention, as it is considered a fidelity protein for mitochondrial function. In some types of cancer, SIRT3 functions as a tumoral promoter, since it keeps ROS levels under a certain threshold compatible with cell viability and proliferation. On the contrary, other studies describe SIRT3 as a tumoral suppressor, as SIRT3 could trigger cell death under stress conditions. Thus, SIRT3 could have a dual role in cancer. In this regard, modulation of SIRT3 activity could be a new target to develop more personalized therapies against cancer.

  3. Metabolic activity is necessary for activation of T suppressor cells by B cells

    International Nuclear Information System (INIS)

    Elkins, K.L.; Stashak, P.W.; Baker, P.J.

    1990-01-01

    Ag-primed B cells must express cell-surface IgM, but not IgD or Ia Ag, and must remain metabolically active, in order to activate suppressor T cells (Ts) specific for type III pneumococcal polysaccharide. Ag-primed B cells that were gamma-irradiated with 1000r, or less, retained the ability to activate Ts; however, Ag-primed B cells exposed to UV light were not able to do so. gamma-Irradiated and UV-treated Ag-primed B cells both expressed comparable levels of cell-surface IgM, and both localized to the spleen after in vivo transfer; neither could proliferate in vitro in response to mitogens. By contrast, gamma-irradiated primed B cells were still able to synthesize proteins, whereas UV-treated primed B cells could not. These findings suggest that in order for Ag-primed B cells to activate Ts, they must (a) express cell-associated IgM (sIgM) antibody bearing the idiotypic determinants of antibody specific for type III pneumococcal polysaccharide, and (b) be able to synthesize protein for either the continued expression of sIgM after cell transfer, or for the elaboration of another protein molecule that is also required for the activation of Ts; this molecule does not appear to be Ia Ag

  4. The tumor suppressor CDX2 opposes pro-metastatic biomechanical modifications of colon cancer cells through organization of the actin cytoskeleton.

    Science.gov (United States)

    Platet, Nadine; Hinkel, Isabelle; Richert, Ludovic; Murdamoothoo, Devadarssen; Moufok-Sadoun, Ahlam; Vanier, Marie; Lavalle, Philippe; Gaiddon, Christian; Vautier, Dominique; Freund, Jean-Noel; Gross, Isabelle

    2017-02-01

    The vast majority of cancer deaths are caused by the formation of metastases rather than the primary tumor itself. Despite this clinical importance, the molecular and cellular events that support the dissemination of cancer cells are not yet fully unraveled. We have previously shown that CDX2, a homeotic transcription factor essential for gut development, acts as a colon-specific tumor suppressor and opposes metastasis. Here, using a combination of biochemical, biophysical, and immunofluorescence techniques, we further investigated the mechanisms promoted by CDX2 that might antagonize tumor cell dissemination. We found that CDX2 expression regulates the transcription of RHO GEFs, thereby activating RHO signaling cascades that lead to reorganization of the actin cytoskeleton and enhanced adherent junctions. Accordingly, we observed by atomic force microscopy (AFM) that colon cancer cells expressing CDX2 are less deformable, a feature that has been shown to correlate with poor metastatic potential. Thus, this study illustrates how the loss of expression of a transcription factor during colon cancer progression modifies the biomechanical characteristics of tumor cells and hence facilitates invasion and metastasis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. HLA-DR-specific suppressor cells after repeated allogeneic sensitizations of human lymphocytes in vitro

    International Nuclear Information System (INIS)

    Sasportes, M.; Fradelizi, D.; Dausset, J.

    1978-01-01

    In conclusion, DR-specific suppressor cells can be induced by repeated in vitro sensitizations. They were able to decrease a secondary proliferation, to suppress consistently, in a primary proliferative assay, when added as third cells (primed twice against a DR antigen [PLT II] and γ-irradiated), the response of unprimed cells towards stimulating cells, which share a DR specificity with the priming cell of the PLT II. The suppression follows the D part of the recombinant haplotype within an HLA-B/D recombinant family and is specific for the DR antigen used twice as stimulator for production of the PLT II

  6. Acquisition of repertoires of suppressor T cells under the influence of macrophages

    International Nuclear Information System (INIS)

    Soejima, T.; Nagayama, A.; Sado, T.; Taniguchi, M.

    1988-01-01

    Acquisition of repertoires and genetic restriction specificities of suppressor T cells (Ts) and their factors were studied by using full allogeneic radiation bone marrow chimera and H-2 congenic pairs, B10.A(3R) and B10.A(5R), which received conventional or cloned macrophages by cell transfer. Suppressor T-cell factor (TsF) from C3H----C57BL/6 or C57BL/6----C3H chimera suppressed only donor but not host-type responses of either C3H or C57BL/6, in an antigen-specific fashion. However, if chimera mice were given conventional or cloned macrophages of the host type, the chimera TsF in turn suppressed both the responses of C3H and C57BL/6 mice but not those of the third party, BALB/c, indicating that macrophages are responsible for the acquisition of host restriction specificity. Similarly, B10.A(5R) mice developed I-Jb restricted Ts or TsF when the B10.A(3R) macrophage cell line was injected at the time of antigen priming. The reverse was also true. B10.A(3R) mice did generate I-Jk restricted Ts when they received the B10.A(5R) macrophage cell line. Thus, the results clearly demonstrated that B10.A(3R) or B10.A(5R) mice potentially possessed their ability to express both I-Jk and I-Jb determinants and that repertoires and genetic restriction specificity of Ts and their TsF were acquired at a macrophage level at the time of antigen-priming

  7. Hyaluronan activates Hyal-2/WWOX/Smad4 signaling and causes bubbling cell death when the signaling complex is overexpressed.

    Science.gov (United States)

    Hsu, Li-Jin; Hong, Qunying; Chen, Shur-Tzu; Kuo, Hsiang-Lin; Schultz, Lori; Heath, John; Lin, Sing-Ru; Lee, Ming-Hui; Li, Dong-Zhang; Li, Zih-Ling; Cheng, Hui-Ching; Armand, Gerard; Chang, Nan-Shan

    2017-03-21

    Malignant cancer cells frequently secrete significant amounts of transforming growth factor beta (TGF-β), hyaluronan (HA) and hyaluronidases to facilitate metastasizing to target organs. In a non-canonical signaling, TGF-β binds membrane hyaluronidase Hyal-2 for recruiting tumor suppressors WWOX and Smad4, and the resulting Hyal-2/WWOX/Smad4 complex is accumulated in the nucleus to enhance SMAD-promoter dependent transcriptional activity. Yeast two-hybrid analysis showed that WWOX acts as a bridge to bind both Hyal-2 and Smad4. When WWOX-expressing cells were stimulated with high molecular weight HA, an increased formation of endogenous Hyal-2/WWOX/Smad4 complex occurred rapidly, followed by relocating to the nuclei in 20-40 min. In WWOX-deficient cells, HA failed to induce Smad2/3/4 relocation to the nucleus. To prove the signaling event, we designed a real time tri-molecular FRET analysis and revealed that HA induces the signaling pathway from ectopic Smad4 to WWOX and finally to p53, as well as from Smad4 to Hyal-2 and then to WWOX. An increased binding of the Smad4/Hyal-2/WWOX complex occurs with time in the nucleus that leads to bubbling cell death. In contrast, HA increases the binding of Smad4/WWOX/p53, which causes membrane blebbing but without cell death. In traumatic brain injury-induced neuronal death, the Hyal-2/WWOX complex was accumulated in the apoptotic nuclei of neurons in the rat brains in 24 hr post injury, as determined by immunoelectron microscopy. Together, HA activates the Hyal-2/WWOX/Smad4 signaling and causes bubbling cell death when the signaling complex is overexpressed.

  8. Modelling radiation-induced cell death and tumour re-oxygenation: local versus global and instant versus delayed cell death

    International Nuclear Information System (INIS)

    Gago-Arias, Araceli; Espinoza, Ignacio; Sánchez-Nieto, Beatriz; Aguiar, Pablo; Pardo-Montero, Juan

    2016-01-01

    The resistance of hypoxic cells to radiation, due to the oxygen dependence of radiosensitivity, is well known and must be taken into account to accurately calculate the radiation induced cell death. A proper modelling of the response of tumours to radiation requires deriving the distribution of oxygen at a microscopic scale. This usually involves solving the reaction-diffusion equation in tumour voxels using a vascularization distribution model. Moreover, re-oxygenation arises during the course of radiotherapy, one reason being the increase of available oxygen caused by cell killing, which can turn hypoxic tumours into oxic. In this work we study the effect of cell death kinetics in tumour oxygenation modelling, analysing how it affects the timing of re-oxygenation, surviving fraction and tumour control. Two models of cell death are compared, an instantaneous cell killing, mimicking early apoptosis, and a delayed cell death scenario in which cells can die shortly after being damaged, as well as long after irradiation. For each of these scenarios, the decrease in oxygen consumption due to cell death can be computed globally (macroscopic voxel average) or locally (microscopic). A re-oxygenation model already used in the literature, the so called full re-oxygenation, is also considered. The impact of cell death kinetics and re-oxygenation on tumour responses is illustrated for two radiotherapy fractionation schemes: a conventional schedule, and a hypofractionated treatment. The results show large differences in the doses needed to achieve 50% tumour control for the investigated cell death models. Moreover, the models affect the tumour responses differently depending on the treatment schedule. This corroborates the complex nature of re-oxygenation, showing the need to take into account the kinetics of cell death in radiation response models. (paper)

  9. In vitro X-ray irradiation of human peripheral blood T lymphocytes enhances suppressor function

    International Nuclear Information System (INIS)

    Ogawa, H.; Tsunematsu, T.

    1983-01-01

    The effect of in vitro X-ray irradiation on human peripheral blood T lymphocytes was studied with regard to their suppressor activity related to the concanavalin A (Con A)-induced suppressor system. To generate suppressor T lymphocytes, purified human T lymphocytes were incubated for 3 days in the first culture, with or without Con A. These lymphocytes were irradiated with various doses of X-ray before, mid or after the culture. After doing a second culture for 6 days, the suppressive influence of these cells on T lymphocyte proliferation rates stimulated with allogeneic mononuclear cells, and B lymphocyte proliferation rates stimulated with pokeweed mitogen was measured. Irradiation of cultures to which Con A had not been added induced much the same level of suppressor activity as seen in the cultures with Con A. The suppressor activity gradually increased with time from the irradiation to the suppressor cell assay. Suppressor T lymphocytes were resistant to X-ray irradiation and independent of DNA synthesis. However, irradiation-induced enhancement was minimal in cultures incubated with con A, regardless of the irradiation time. (author)

  10. [Methuosis: a novel type of cell death].

    Science.gov (United States)

    Cai, Hongbing; Liu, Jinkun; Fan, Qin; Li, Xin

    2013-12-01

    Cell death is a major physiological or pathological phenomenon in life activities. The classic forms of cell death include apoptosis, necrosis, and autophagy. Recently, a novel type of cell death has been observed and termed as methuosis, in which excessive stimuli can induce cytoplasmic uptake and accumulation of small bubbles that gradually merge into giant vacuoles, eventually leading to decreased cellular metabolic activity, cell membrane rupture and cell death. In this article, we describe the nomenclature, morphological characteristics and underlying mechanisms of methuosis, compare methuosis with autophagy, oncosis and paraptosis, and review the related researches.

  11. Radiation of different human melanoma cell lines increased expression of RHOB. Level of this tumor suppressor gene in different cell lines

    International Nuclear Information System (INIS)

    Notcovich, C.; Molinari, B.; Duran, H.; Delgado González, D.; Sánchez Crespo, R.

    2013-01-01

    Previous results of our group show that a correlation exists between intrinsic radiosensitivity of human melanoma cells and cell death by apoptosis. RhoB is a small GTPase that regulates cytoskeletal organization. Besides, is related to the process of apoptosis in cells exposed to DNA damage as radiation. Also, RhoB levels decrease in a wide variety of tumors with the tumor stage, being considered a tumor suppressor gene due to its antiproliferative and proapoptotic effect. The aim of this study was to analyze the expression of RhoB in different human melanoma cell lines in relation to melanocytes, and evaluate the effect of gamma radiation on the expression of RhoB. We used the A375, SB2 and Meljcell lines, and the derived from melanocytes Pig1. It was found for all three tumor lines RhoB expression levels significantly lower than those of Pig1 (p <0.05), as assessed by semiquantitative RT-PCR . When tumor cells were irradiated to a dose of 2Gyinduction was observed at 3 hours RhoB irradiation. RhoB expression increased in all lines relative to non-irradiated control, showing a greater induction ( p< 0.05) for the more radiosensitive line SB2, consistent with apoptosis in response to radiation. The results allow for the first time in melanoma demonstrate that RhoB, as well as in other tumor types, has a lower expression in tumor cells than their normal counterparts. Moreover, induction in the expression of RhoB in irradiated cells may be associated with the process of radiation-induced apoptosis. The modulation of RhoB could be a new tool to sensitize radioresistant melanoma. (author)

  12. Morphological classification of plant cell deaths.

    Science.gov (United States)

    van Doorn, W G; Beers, E P; Dangl, J L; Franklin-Tong, V E; Gallois, P; Hara-Nishimura, I; Jones, A M; Kawai-Yamada, M; Lam, E; Mundy, J; Mur, L A J; Petersen, M; Smertenko, A; Taliansky, M; Van Breusegem, F; Wolpert, T; Woltering, E; Zhivotovsky, B; Bozhkov, P V

    2011-08-01

    Programmed cell death (PCD) is an integral part of plant development and of responses to abiotic stress or pathogens. Although the morphology of plant PCD is, in some cases, well characterised and molecular mechanisms controlling plant PCD are beginning to emerge, there is still confusion about the classification of PCD in plants. Here we suggest a classification based on morphological criteria. According to this classification, the use of the term 'apoptosis' is not justified in plants, but at least two classes of PCD can be distinguished: vacuolar cell death and necrosis. During vacuolar cell death, the cell contents are removed by a combination of autophagy-like process and release of hydrolases from collapsed lytic vacuoles. Necrosis is characterised by early rupture of the plasma membrane, shrinkage of the protoplast and absence of vacuolar cell death features. Vacuolar cell death is common during tissue and organ formation and elimination, whereas necrosis is typically found under abiotic stress. Some examples of plant PCD cannot be ascribed to either major class and are therefore classified as separate modalities. These are PCD associated with the hypersensitive response to biotrophic pathogens, which can express features of both necrosis and vacuolar cell death, PCD in starchy cereal endosperm and during self-incompatibility. The present classification is not static, but will be subject to further revision, especially when specific biochemical pathways are better defined.

  13. Autophagic cell death: Loch Ness monster or endangered species?

    Science.gov (United States)

    Shen, Han-Ming; Codogno, Patrice

    2011-05-01

    The concept of autophagic cell death was first established based on observations of increased autophagic markers in dying cells. The major limitation of such a morphology-based definition of autophagic cell death is that it fails to establish the functional role of autophagy in the cell death process, and thus contributes to the confusion in the literature regarding the role of autophagy in cell death and cell survival. Here we propose to define autophagic cell death as a modality of non-apoptotic or necrotic programmed cell death in which autophagy serves as a cell death mechanism, upon meeting the following set of criteria: (i) cell death occurs without the involvement of apoptosis; (ii) there is an increase of autophagic flux, and not just an increase of the autophagic markers, in the dying cells; and (iii) suppression of autophagy via both pharmacological inhibitors and genetic approaches is able to rescue or prevent cell death. In light of this new definition, we will discuss some of the common problems and difficulties in the study of autophagic cell death and also revisit some well-reported cases of autophagic cell death, aiming to achieve a better understanding of whether autophagy is a real killer, an accomplice or just an innocent bystander in the course of cell death. At present, the physiological relevance of autophagic cell death is mainly observed in lower eukaryotes and invertebrates such as Dictyostelium discoideum and Drosophila melanogaster. We believe that such a clear definition of autophagic cell death will help us study and understand the physiological or pathological relevance of autophagic cell death in mammals.

  14. PHTS, a novel putative tumor suppressor, is involved in the transformation reversion of HeLaHF cells independently of the p53 pathway

    International Nuclear Information System (INIS)

    Yu Dehua; Fan, Wufang; Liu, Guohong; Nguy, Vivian; Chatterton, Jon E.; Long Shilong; Ke, Ning; Meyhack, Bernd; Bruengger, Adrian; Brachat, Arndt; Wong-Staal, Flossie; Li, Qi-Xiang

    2006-01-01

    HeLaHF is a non-transformed revertant of HeLa cells, likely resulting from the activation of a putative tumor suppressor(s). p53 protein was stabilized in this revertant and reactivated for certain transactivation functions. Although p53 stabilization has not conclusively been linked to the reversion, it is clear that the genes in p53 pathway are involved. The present study confirms the direct role of p53 in HeLaHF reversion by demonstrating that RNAi-mediated p53 silencing partially restores anchorage-independent growth potential of the revertant through the suppression of anoikis. In addition, we identified a novel gene, named PHTS, with putative tumor suppressor properties, and showed that this gene is also involved in HeLaHF reversion independently of the p53 pathway. Expression profiling revealed that PHTS is one of the genes that is up-regulated in HeLaHF but not in HeLa. It encodes a putative protein with CD59-like domains. RNAi-mediated PHTS silencing resulted in the partial restoration of transformation (anchorage-independent growth) in HeLaHF cells, similar to that of p53 gene silencing, implying its tumor suppressor effect. However, the observed increased transformation potential by PHTS silencing appears to be due to an increased anchorage-independent proliferation rate rather than suppression of anoikis, unlike the effect of p53 silencing. p53 silencing did not affect PHTS gene expression, and vice versa, suggesting PHTS may function in a new and p53-independent tumor suppressor pathway. Furthermore, over-expression of PHTS in different cancer cell lines, in addition to HeLa, reduces cell growth likely via induced apoptosis, confirming the broad PHTS tumor suppressor properties

  15. Porcine circovirus-2 capsid protein induces cell death in PK15 cells

    Energy Technology Data Exchange (ETDEWEB)

    Walia, Rupali; Dardari, Rkia, E-mail: rdardari@ucalgary.ca; Chaiyakul, Mark; Czub, Markus

    2014-11-15

    Studies have shown that Porcine circovirus (PCV)-2 induces apoptosis in PK15 cells. Here we report that cell death is induced in PCV2b-infected PK15 cells that express Capsid (Cap) protein and this effect is enhanced in interferon gamma (IFN-γ)-treated cells. We further show that transient PCV2a and 2b-Cap protein expression induces cell death in PK15 cells at rate similar to PCV2 infection, regardless of Cap protein localization. These data suggest that Cap protein may have the capacity to trigger different signaling pathways involved in cell death. Although further investigation is needed to gain deeper insights into the nature of the pathways involved in Cap-induced cell death, this study provides evidence that PCV2-induced cell death in kidney epithelial PK15 cells can be mapped to the Cap protein and establishes the need for future research regarding the role of Cap-induced cell death in PCV2 pathogenesis. - Highlights: • IFN-γ enhances PCV2 replication that leads to cell death in PK15 cells. • IFN-γ enhances nuclear localization of the PCV2 Capsid protein. • Transient PCV2a and 2b-Capsid protein expression induces cell death. • Cell death is not dictated by specific Capsid protein sub-localization.

  16. Radiation-induced cell death in embryogenic cells of coniferous plants

    International Nuclear Information System (INIS)

    Watanabe, Yoshito; Homma-Takeda, Shino; Yukawa, Masae; Nishimura, Yoshikazu; Sasamoto, Hamako; Takahagi, Masahiko

    2004-01-01

    Reproductive processes are particularly radiosensitive in plant development, which was clearly illustrated in reduction of seed formation in native coniferous plants around Chernobyl after the nuclear accident. For the purpose to investigate the effects of ionizing radiation on embryonic formation in coniferous plants, we used an embryo-derived embryogenic cell culture of a Japanese native coniferous plant, Japanese cedar (Cryplomeria japonica). The embryogenic cells were so radiosensitive that most of the cells died by X-ray irradiation of 5 Gy. This indicated that the embryogenic cells are as radiosensitive as some mammalian cells including lymphocytes. We considered that this type of radiosensitive cell death in the embryogenic cells should be responsible for reproductive damages of coniferous plants by low dose of ionizing radiation. The cell death of the embryogenic cells was characteristic of nuclear DNA fragmentation, which is typically observed in radiation-induced programmed cell death, i.e. apoptosis, in mammalian cells. On the other hand, cell death with nuclear DNA fragmentation did not develop by X-ray irradiation in vegetative cells including meristematic cells of Japanese cedar. This suggests that an apoptosis-like programmed cell death should develop cell-specifically in embryogenic cells by ionizing radiation. The abortion of embryogenic cells may work to prevent transmission of radiation-induced genetic damages to the descendants. (author)

  17. Introduction of in vitro transcribed ENO1 mRNA into neuroblastoma cells induces cell death

    International Nuclear Information System (INIS)

    Ejeskär, Katarina; Krona, Cecilia; Carén, Helena; Zaibak, Faten; Li, Lingli; Martinsson, Tommy; Ioannou, Panayiotis A

    2005-01-01

    Neuroblastoma is a solid tumour of childhood often with an unfavourable outcome. One common genetic feature in aggressive tumours is 1p-deletion. The α-enolase (ENO1) gene is located in chromosome region 1p36.2, within the common region of deletion in neuroblastoma. One alternative translated product of the ENO1 gene, known as MBP-1, acts as a negative regulator of the c-myc oncogene, making the ENO1 gene a candidate as a tumour suppressor gene. Methods used in this study are transfection of cDNA-vectors and in vitro transcribed mRNA, cell growth assay, TUNEL-assay, real-time RT-PCR (TaqMan) for expression studies, genomic sequencing and DHPLC for mutation detection. Here we demonstrate that transfection of ENO1 cDNA into 1p-deleted neuroblastoma cell lines causes' reduced number of viable cells over time compared to a negative control and that it induces apoptosis. Interestingly, a similar but much stronger dose-dependent reduction of cell growth was observed by transfection of in vitro transcribed ENO1 mRNA into neuroblastoma cells. These effects could also be shown in non-neuroblastoma cells (293-cells), indicating ENO1 to have general tumour suppressor activity. Expression of ENO1 is detectable in primary neuroblastomas of all different stages and no difference in the level of expression can be detected between 1p-deleted and 1p-intact tumour samples. Although small numbers (11 primary neuroblastomas), there is some evidence that Stage 4 tumours has a lower level of ENO1-mRNA than Stage 2 tumours (p = 0.01). However, mutation screening of 44 primary neuroblastomas of all different stages, failed to detect any mutations. Our studies indicate that ENO1 has tumour suppressor activity and that high level of ENO1 expression has growth inhibitory effects

  18. Mitochondrial fission proteins regulate programmed cell death in yeast.

    Science.gov (United States)

    Fannjiang, Yihru; Cheng, Wen-Chih; Lee, Sarah J; Qi, Bing; Pevsner, Jonathan; McCaffery, J Michael; Hill, R Blake; Basañez, Gorka; Hardwick, J Marie

    2004-11-15

    The possibility that single-cell organisms undergo programmed cell death has been questioned in part because they lack several key components of the mammalian cell death machinery. However, yeast encode a homolog of human Drp1, a mitochondrial fission protein that was shown previously to promote mammalian cell death and the excessive mitochondrial fragmentation characteristic of apoptotic mammalian cells. In support of a primordial origin of programmed cell death involving mitochondria, we found that the Saccharomyces cerevisiae homolog of human Drp1, Dnm1, promotes mitochondrial fragmentation/degradation and cell death following treatment with several death stimuli. Two Dnm1-interacting factors also regulate yeast cell death. The WD40 repeat protein Mdv1/Net2 promotes cell death, consistent with its role in mitochondrial fission. In contrast to its fission function in healthy cells, Fis1 unexpectedly inhibits Dnm1-mediated mitochondrial fission and cysteine protease-dependent cell death in yeast. Furthermore, the ability of yeast Fis1 to inhibit mitochondrial fission and cell death can be functionally replaced by human Bcl-2 and Bcl-xL. Together, these findings indicate that yeast and mammalian cells have a conserved programmed death pathway regulated by a common molecular component, Drp1/Dnm1, that is inhibited by a Bcl-2-like function.

  19. The role of baculovirus apoptotic suppressors in AcMNPV-mediated translation arrest in Ld652Y cells

    International Nuclear Information System (INIS)

    Thiem, Suzanne M.; Chejanovsky, Nor

    2004-01-01

    Infecting the insect cell line IPLB-Ld652Y with the baculovirus Autographa californica multinucleocapsid nucleopolyhedrovirus (AcMNPV) results in global translation arrest, which correlates with the presence of the AcMNPV apoptotic suppressor, p35. In this study, we investigated the role of apoptotic suppression on AcMNPV-induced translation arrest. Infecting cells with AcMNPV bearing nonfunctional mutant p35 did not result in global translation arrest. In contrast, global translation arrest was observed in cells infected with AcMNPV in which p35 was replaced with Opiap, Cpiap, or p49, baculovirus apoptotic suppressors that block apoptosis by different mechanisms than p35. These results indicated that suppressing apoptosis triggered translation arrest in AcMNPV-infected Ld652Y cells. Experiments using the DNA synthesis inhibitor aphidicolin and temperature shift experiments, using the AcMNPV replication mutants ts8 and ts8Δp35, indicated that translation arrest initiated during the early phase of infection, but events during the late phase were required for global translation arrest. Peptide caspase inhibitors could not substitute for baculovirus apoptotic suppressors to induce translation arrest in Ld652Y cells infected with a p35-null virus. However, if the p35-null-AcMNPV also carried hrf-1, a novel baculovirus host range gene, progeny virus was produced and treatment with peptide caspase inhibitors enhanced translation of a late viral gene transcript. Together, these results indicate that translation arrest in AcMNPV-infected Ld652Y cells is due to the anti-apoptotic function of p35, but suggests that rather than simply preventing caspase activation, its activity enhances signaling to a separate translation arrest pathway, possibly by stimulating the late stages of the baculovirus infection cycle

  20. Myeloid-derived suppressor cells mediate immune suppression in spinal cord injury.

    Science.gov (United States)

    Wang, Lei; Yu, Wei-bo; Tao, Lian-yuan; Xu, Qing

    2016-01-15

    Spinal cord injury (SCI) is characterized by the loss of motor and sensory functions in areas below the level of the lesion and numerous accompanying deficits. Previous studies have suggested that myeloid-derived suppressor cell (MDSC)-induced immune depression may play a pivotal role in the course of SCI. However, the concrete mechanism of these changes regarding immune suppression remains unknown. Here, we created an SCI mouse model to gain further evidence regarding the relationship between MDSCs following SCI and T lymphocyte suppression. We showed that in the SCI mouse model, the expanding MDSCs have the capacity to suppress T cell proliferation, and this suppression could be reversed by blocking the arginase. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Early death, late death and repair factor in three human tumour cell lines

    International Nuclear Information System (INIS)

    Courdi, A.; Gioanni, J.; Mari, D.; Chauvel, P.

    1997-01-01

    The in vivo colony method used to generate survival curves following exposure to ionizing irradiation allows to score large clones, representing surviving cells, and small colonies, representing late reproductive death. By subtraction, early-dying cells can be estimated. In the three human tumour cell lines examined, we have observed that early cell death is a major mode of action of irradiation. The contribution of early cell death to total mortality increases as the dose increases. Moreover, repair due to dose-splitting and delayed plating in densely-inhibited cells is not observed in early-dying cells. (authors)

  2. Hyaluronan activates Hyal-2/WWOX/Smad4 signaling and causes bubbling cell death when the signaling complex is overexpressed

    Science.gov (United States)

    Hsu, Li-Jin; Hong, Qunying; Chen, Shur-Tzu; Kuo, Hsiang-Lin; Schultz, Lori; Heath, John; Lin, Sing-Ru; Lee, Ming-Hui; Li, Dong-Zhang; Li, Zih-Ling; Cheng, Hui-Ching; Armand, Gerard; Chang, Nan-Shan

    2017-01-01

    Malignant cancer cells frequently secrete significant amounts of transforming growth factor beta (TGF-β), hyaluronan (HA) and hyaluronidases to facilitate metastasizing to target organs. In a non-canonical signaling, TGF-β binds membrane hyaluronidase Hyal-2 for recruiting tumor suppressors WWOX and Smad4, and the resulting Hyal-2/WWOX/Smad4 complex is accumulated in the nucleus to enhance SMAD-promoter dependent transcriptional activity. Yeast two-hybrid analysis showed that WWOX acts as a bridge to bind both Hyal-2 and Smad4. When WWOX-expressing cells were stimulated with high molecular weight HA, an increased formation of endogenous Hyal-2/WWOX/Smad4 complex occurred rapidly, followed by relocating to the nuclei in 20-40 min. In WWOX-deficient cells, HA failed to induce Smad2/3/4 relocation to the nucleus. To prove the signaling event, we designed a real time tri-molecular FRET analysis and revealed that HA induces the signaling pathway from ectopic Smad4 to WWOX and finally to p53, as well as from Smad4 to Hyal-2 and then to WWOX. An increased binding of the Smad4/Hyal-2/WWOX complex occurs with time in the nucleus that leads to bubbling cell death. In contrast, HA increases the binding of Smad4/WWOX/p53, which causes membrane blebbing but without cell death. In traumatic brain injury-induced neuronal death, the Hyal-2/WWOX complex was accumulated in the apoptotic nuclei of neurons in the rat brains in 24 hr post injury, as determined by immunoelectron microscopy. Together, HA activates the Hyal-2/WWOX/Smad4 signaling and causes bubbling cell death when the signaling complex is overexpressed. PMID:27845895

  3. Evidence against suppressor cell involvement in naturally acquired tolerance of a minor histocompatibility antigen

    International Nuclear Information System (INIS)

    Johnson, L.L.

    1991-01-01

    The hypothesis was investigated that suppressor cells may be responsible for maintenance of immunologic tolerance of a minor H3 antigen in mice that express the antigen naturally. Lymphoid cell populations from B6.C-H-24c (HW54) mice, a congenic-resistant strain histoincompatible with H-24b-expressing C57BL/6 (B6) mice only with respect to the H-24 locus, were examined in cell-transfer experiments to see if they contained naturally arising H-24c-specific suppressor cells. The H-24 antigen was chosen for these studies because, unlike most other minor and major histocompatibility (H) antigens, it is not detectable on mature lymphoid cells by any of several functional criteria. Thus transfer of HW54 lymphoid cells to B6 hosts could be done without the complication of inducing hyporesponsiveness de novo in the host, as occurs with other minor H antigens that are expressed on lymphocytes. B6 hosts were given HW54 skin grafts along with HW54 lymphoid cells to assess their tolerance of the H-24c-encoded antigen. The hosts were either (1) normal, nonimmune B6 mice; (2) B6 mice rendered immunodeficient by thymectomy and irradiation (TxB) and repopulated with H-24c-immune B6 lymphocytes; or (3) TxB B6 hosts repopulated with nonimmune B6 lymphocytes. In each case it was found that the additionally infused HW54 lymphoid cells did not suppress the ability of these hosts to reject HW54 skin grafts. In other words, HW54 lymphoid cells appear not to possess suppressive activity specific for the H-24c antigen that might maintain antigen-specific natural tolerance. Additional experiments were performed to determine whether HW54 lymphoid cells can inhibit the ability of sublethally irradiated B6 mice to regain the capacity to reject HW54 skin

  4. Enlightened protein: Fhit tumor suppressor protein structure and function and its role in the toxicity of protoporphyrin IX-mediated photodynamic reaction

    International Nuclear Information System (INIS)

    Zawacka-Pankau, Joanna

    2009-01-01

    The Fhit tumor suppressor protein possesses Ap 3 A (diadenosine triphosphate - ApppA) hydrolytic activity in vitro and its gene is found inactive in many pre-malignant states due to gene inactivation. For several years Fhit has been a widely investigated protein as its cellular function still remains largely unsolved. Fhit was shown to act as a molecular 'switch' of cell death via cascade operating on the influence of ATR-Chk1 pathway but also through the mitochondrial apoptotic pathway. Notably, Fhit was reported by our group to enhance the overall eradication effect of porphyrin-mediated photodynamic treatment (PDT). In this review the up-to-date findings on Fhit protein as a tumor suppressor and its role in PDT are presented.

  5. Unexpected functional similarities between gatekeeper tumour suppressor genes and proto-oncogenes revealed by systems biology.

    Science.gov (United States)

    Zhao, Yongzhong; Epstein, Richard J

    2011-05-01

    Familial tumor suppressor genes comprise two subgroups: caretaker genes (CTs) that repair DNA, and gatekeeper genes (GKs) that trigger cell death. Since GKs may also induce cell cycle delay and thus enhance cell survival by facilitating DNA repair, we hypothesized that the prosurvival phenotype of GKs could be selected during cancer progression, and we used a multivariable systems biology approach to test this. We performed multidimensional data analysis, non-negative matrix factorization and logistic regression to compare the features of GKs with those of their putative antagonists, the proto-oncogenes (POs), as well as with control groups of CTs and functionally unrelated congenital heart disease genes (HDs). GKs and POs closely resemble each other, but not CTs or HDs, in terms of gene structure (Pexpression level and breadth (Pimplied suggest a common functional attribute that is strongly negatively selected-that is, a shared phenotype that enhances cell survival. The counterintuitive finding of similar evolutionary pressures affecting GKs and POs raises an intriguing possibility: namely, that cancer microevolution is accelerated by an epistatic cascade in which upstream suppressor gene defects subvert the normal bifunctionality of wild-type GKs by constitutively shifting the phenotype away from apoptosis towards survival. If correct, this interpretation would explain the hitherto unexplained phenomenon of frequent wild-type GK (for example, p53) overexpression in tumors.

  6. Morphological classification of plant cell deaths

    DEFF Research Database (Denmark)

    van Doorn, W.G.; Beers, E.P.; Dangl, J.L.

    2011-01-01

    , which can express features of both necrosis and vacuolar cell death, PCD in starchy cereal endosperm and during self-incompatibility. The present classification is not static, but will be subject to further revision, especially when specific biochemical pathways are better defined....... the classification of PCD in plants. Here we suggest a classification based on morphological criteria. According to this classification, the use of the term 'apoptosis' is not justified in plants, but at least two classes of PCD can be distinguished: vacuolar cell death and necrosis. During vacuolar cell death...

  7. Drosophila Ninjurin A induces nonapoptotic cell death.

    Directory of Open Access Journals (Sweden)

    Sarah Broderick

    Full Text Available Ninjurins are conserved transmembrane proteins that are upregulated across species in response to injury and stress. Their biological functions are not understood, in part because there have been few in vivo studies of their function. We analyzed the expression and function of one of three Drosophila Ninjurins, NijA. We found that NijA protein is redistributed to the cell surface in larval immune tissues after septic injury and is upregulated by the Toll pathway. We generated a null mutant of NijA, which displayed no detectable phenotype. In ectopic expression studies, NijA induced cell death, as evidenced by cell loss and acridine orange staining. These dying cells did not display hallmarks of apoptotic cells including TUNEL staining and inhibition by p35, indicating that NijA induced nonapoptotic cell death. In cell culture, NijA also induced cell death, which appeared to be cell autonomous. These in vivo studies identify a new role for the Ninjurin family in inducing nonapoptotic cell death.

  8. The Tumor Suppressor Hace1 Is a Critical Regulator of TNFR1-Mediated Cell Fate

    Directory of Open Access Journals (Sweden)

    Luigi Tortola

    2016-05-01

    Full Text Available Summary: The HECT domain E3 ligase HACE1 has been identified as a tumor suppressor in multiple cancers. Here, we report that HACE1 is a central gatekeeper of TNFR1-induced cell fate. Genetic inactivation of HACE1 inhibits TNF-stimulated NF-κB activation and TNFR1-NF-κB-dependent pathogen clearance in vivo. Moreover, TNF-induced apoptosis was impaired in hace1 mutant cells and knockout mice in vivo. Mechanistically, HACE1 is essential for the ubiquitylation of the adaptor protein TRAF2 and formation of the apoptotic caspase-8 effector complex. Intriguingly, loss of HACE1 does not impair TNFR1-mediated necroptotic cell fate via RIP1 and RIP3 kinases. Loss of HACE1 predisposes animals to colonic inflammation and carcinogenesis in vivo, which is markedly alleviated by genetic inactivation of RIP3 kinase and TNFR1. Thus, HACE1 controls TNF-elicited cell fate decisions and exerts tumor suppressor and anti-inflammatory activities via a TNFR1-RIP3 kinase-necroptosis pathway. : Tortola et al. report that the E3 ubiquitin ligase HACE1 is a gatekeeper of TNFR1-mediated cell fate. Hace1 deficiency impairs TNF-driven NF-κB activation and apoptosis and predisposes cells to necroptosis. Consequently, hace1–/– mice show enhanced colitis and colon cancer, which can be reverted by inactivation of pro-necroptotic kinase RIP3 and TNFR1.

  9. Targeting myeloid-derived suppressor cells augments antitumor activity against lung cancer

    Directory of Open Access Journals (Sweden)

    Srivastava MK

    2012-10-01

    Full Text Available Minu K Srivastava,1,2 Li Zhu,1,2 Marni Harris-White,2 Min Huang,1–3 Maie St John,1,3 Jay M Lee,1,3 Ravi Salgia,4 Robert B Cameron,1,3,5 Robert Strieter,6 Steven Dubinett,1–3 Sherven Sharma1–31Department of Medicine, UCLA Lung Cancer Research Program, David Geffen School of Medicine at UCLA, Los Angeles, CA, 2Molecular Gene Medicine Laboratory, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, 3Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, CA, 4Department of Medicine, University of Chicago, Chicago, IL, 5Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, 6Department of Medicine, University of Virginia, Charlottesville, VA, USAAbstract: Lung cancer evades host immune surveillance by dysregulating inflammation. Tumors and their surrounding stromata produce growth factors, cytokines, and chemokines that recruit, expand, and/or activate myeloid-derived suppressor cells (MDSCs. MDSCs regulate immune responses and are frequently found in malignancy. In this review the authors discuss tumor-MDSC interactions that suppress host antitumor activities and the authors' recent findings regarding MDSC depletion that led to improved therapeutic vaccination responses against lung cancer. Despite the identification of a repertoire of tumor antigens, hurdles persist for immune-based anticancer therapies. It is likely that combined therapies that address the multiple immune deficits in cancer patients will be required for effective therapy. MDSCs play a major role in the suppression of T-cell activation and they sustain tumor growth, proliferation, and metastases. Regulation of MDSC recruitment, differentiation or expansion, and inhibition of the MDSC suppressive function with pharmacologic agents will be useful in the control of cancer growth and progression. Pharmacologic agents that regulate MDSCs may be more effective when combined with

  10. Live-cell visualization of gasdermin D-driven pyroptotic cell death.

    Science.gov (United States)

    Rathkey, Joseph K; Benson, Bryan L; Chirieleison, Steven M; Yang, Jie; Xiao, Tsan S; Dubyak, George R; Huang, Alex Y; Abbott, Derek W

    2017-09-01

    Pyroptosis is a form of cell death important in defenses against pathogens that can also result in a potent and sometimes pathological inflammatory response. During pyroptosis, GSDMD (gasdermin D), the pore-forming effector protein, is cleaved, forms oligomers, and inserts into the membranes of the cell, resulting in rapid cell death. However, the potent cell death induction caused by GSDMD has complicated our ability to understand the biology of this protein. Studies aimed at visualizing GSDMD have relied on expression of GSDMD fragments in epithelial cell lines that naturally lack GSDMD expression and also lack the proteases necessary to cleave GSDMD. In this work, we performed mutagenesis and molecular modeling to strategically place tags and fluorescent proteins within GSDMD that support native pyroptosis and facilitate live-cell imaging of pyroptotic cell death. Here, we demonstrate that these fusion proteins are cleaved by caspases-1 and -11 at Asp-276. Mutations that disrupted the predicted p30-p20 autoinhibitory interface resulted in GSDMD aggregation, supporting the oligomerizing activity of these mutations. Furthermore, we show that these novel GSDMD fusions execute inflammasome-dependent pyroptotic cell death in response to multiple stimuli and allow for visualization of the morphological changes associated with pyroptotic cell death in real time. This work therefore provides new tools that not only expand the molecular understanding of pyroptosis but also enable its direct visualization. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Endoplasmic reticulum involvement in yeast cell death

    International Nuclear Information System (INIS)

    Nicanor Austriaco, O.

    2012-01-01

    Yeast cells undergo programed cell death (PCD) with characteristic markers associated with apoptosis in mammalian cells including chromatin breakage, nuclear fragmentation, reactive oxygen species generation, and metacaspase activation. Though significant research has focused on mitochondrial involvement in this phenomenon, more recent work with both Saccharomyces cerevisiae and Schizosaccharomyces pombe has also implicated the endoplasmic reticulum (ER) in yeast PCD. This minireview provides an overview of ER stress-associated cell death (ER-SAD) in yeast. It begins with a description of ER structure and function in yeast before moving to a discussion of ER-SAD in both mammalian and yeast cells. Three examples of yeast cell death associated with the ER will be highlighted here including inositol starvation, lipid toxicity, and the inhibition of N-glycosylation. It closes by suggesting ways to further examine the involvement of the ER in yeast cell death.

  12. Immune suppressor factor confers stromal cell line with enhanced supporting activity for hematopoietic stem cells

    International Nuclear Information System (INIS)

    Nakajima, Hideaki; Shibata, Fumi; Fukuchi, Yumi; Goto-Koshino, Yuko; Ito, Miyuki; Urano, Atsushi; Nakahata, Tatsutoshi; Aburatani, Hiroyuki; Kitamura, Toshio

    2006-01-01

    Immune suppressor factor (ISF) is a subunit of the vacuolar ATPase proton pump. We earlier identified a short form of ISF (ShIF) as a stroma-derived factor that supports cytokine-independent growth of mutant Ba/F3 cells. Here, we report that ISF/ShIF supports self-renewal and expansion of primary hematopoietic stem cells (HSCs). Co-culture of murine bone marrow cells with a stromal cell line overexpressing ISF or ShIF (MS10/ISF or MS10/ShIF) not only enhanced their colony-forming activity and the numbers of long-term culture initiating cells, but also maintained the competitive repopulating activity of HSC. This stem cell supporting activity depended on the proton-transfer function of ISF/ShIF. Gene expression analysis of ISF/ShIF-transfected cell lines revealed down-regulation of secreted frizzled-related protein-1 and tissue inhibitor of metalloproteinase-3, and the restoration of their expressions in MS10/ISF cells partially reversed its enhanced LTC-IC supporting activity to a normal level. These results suggest that ISF/ShIF confers stromal cells with enhanced supporting activities for HSCs by modulating Wnt-activity and the extracellular matrix

  13. MiR-206 functions as a tumor suppressor and directly targets K-Ras in human oral squamous cell carcinoma [Retraction

    Directory of Open Access Journals (Sweden)

    Lin FO

    2016-10-01

    Full Text Available The Editor-in-Chief and Publisher of OncoTargets and Therapy have been alerted to unacceptable levels of duplication with another published paper: Zhang D, Ni Z, Xu X, and Xiao J. MiR-32 Functions as a Tumor Suppressor and Directly Targets EZH2 in Human Oral Squamous Cell Carcinoma. Medical Science Monitor. 20:2527–2535, 2014.Accordingly, we retract Lin FO, Yao LJ, Xiao J, Liu DF, and Ni ZY. MiR-206 functions as a tumor suppressor and directly targets K-Ras in human oral squamous cell carcinoma. OncoTargets and Therapy. 2014;7:1583–1591.This Retraction relates to 

  14. Cholesterol and phytosterols differentially regulate the expression of caveolin 1 and a downstream prostate cell growth-suppressor gene

    Science.gov (United States)

    Ifere, Godwin O.; Equan, Anita; Gordon, Kereen; Nagappan, Peri; Igietseme, Joseph U.; Ananaba, Godwin A.

    2010-01-01

    Background The purpose of our study was to show the distinction between the apoptotic and anti-proliferative signaling of phytosterols and cholesterol enrichment in prostate cancer cell lines, mediated by the differential transcription of caveolin-1, and N-myc downstream regulated gene1 (NDRG1), a pro-apoptotic androgen-regulated tumor suppressor. Methods PC-3 and DU145 cells were treated with sterols (cholesterol and phytosterols) for 72 h, followed by trypan blue dye exclusion measurement of necrosis and cell growth measured with a Coulter counter. Sterol induction of cell growth-suppressor gene expression was evaluated by mRNA transcription using RT-PCR, while cell cycle analysis was performed by FACS analysis. Altered expression of Ndrg1 protein was confirmed by Western blot analysis. Apoptosis was evaluated by real time RT-PCR amplification of P53, Bcl-2 gene and its related pro- and anti-apoptotic family members. Results Physiological doses (16 µM) of cholesterol and phytosterols were not cytotoxic in these cells. Cholesterol enrichment promoted cell growth (Pphytosterols significantly induced growth-suppression (Pphytosterols decreased mitotic subpopulations. We demonstrated for the first time that cholesterols concertedly attenuated the expression of caveolin-1(cav-1) and NDRG1 genes in both prostate cancer cell lines. Phytosterols had the opposite effect by inducing overexpression of cav-1, a known mediator of androgen-dependent signals that presumably control cell growth or apoptosis. Conclusions Cholesterol and phytosterol treatment differentially regulated the growth of prostate cancer cells and the expression of p53 and cav-1, a gene that regulates androgen-regulated signals. These sterols also differentially regulated cell cycle arrest, downstream pro-apoptotic androgen-regulated tumor-suppressor, NDRG1 suggesting that cav-1 may mediate pro-apoptotic NDRG1 signals. Elucidation of the mechanism for sterol modulation of growth and apoptosis signaling

  15. Suppressor Analysis of the Fusogenic Lambda Spanins.

    Science.gov (United States)

    Cahill, Jesse; Rajaure, Manoj; Holt, Ashley; Moreland, Russell; O'Leary, Chandler; Kulkarni, Aneesha; Sloan, Jordan; Young, Ry

    2017-07-15

    The final step of lysis in phage λ infections of Escherichia coli is mediated by the spanins Rz and Rz1. These proteins form a complex that bridges the cell envelope and that has been proposed to cause fusion of the inner and outer membranes. Accordingly, mutations that block spanin function are found within coiled-coil domains and the proline-rich region, motifs essential in other fusion systems. To gain insight into spanin function, pseudorevertant alleles that restored plaque formation for lysis-defective mutants of Rz and Rz1 were selected. Most second-site suppressors clustered within a coiled-coil domain of Rz near the outer leaflet of the cytoplasmic membrane and were not allele specific. Suppressors largely encoded polar insertions within the hydrophobic core of the coiled-coil interface. Such suppressor changes resulted in decreased proteolytic stability of the Rz double mutants in vivo Unlike the wild type, in which lysis occurs while the cells retain a rod shape, revertant alleles with second-site suppressor mutations supported lysis events that were preceded by spherical cell formation. This suggests that destabilization of the membrane-proximal coiled coil restores function for defective spanin alleles by increasing the conformational freedom of the complex at the cost of its normal, all-or-nothing functionality. IMPORTANCE Caudovirales encode cell envelope-spanning proteins called spanins, which are thought to fuse the inner and outer membranes during phage lysis. Recent genetic analysis identified the functional domains of the lambda spanins, which are similar to class I viral fusion proteins. While the pre- and postfusion structures of model fusion systems have been well characterized, the intermediate structure(s) formed during the fusion reaction remains elusive. Genetic analysis would be expected to identify functional connections between intermediates. Since most membrane fusion systems are not genetically tractable, only few such

  16. Epigenetic profiling of cutaneous T-cell lymphoma: promoter hypermethylation of multiple tumor suppressor genes including BCL7a, PTPRG, and p73.

    Science.gov (United States)

    van Doorn, Remco; Zoutman, Willem H; Dijkman, Remco; de Menezes, Renee X; Commandeur, Suzan; Mulder, Aat A; van der Velden, Pieter A; Vermeer, Maarten H; Willemze, Rein; Yan, Pearlly S; Huang, Tim H; Tensen, Cornelis P

    2005-06-10

    To analyze the occurrence of promoter hypermethylation in primary cutaneous T-cell lymphoma (CTCL) on a genome-wide scale, focusing on epigenetic alterations with pathogenetic significance. DNA isolated from biopsy specimens of 28 patients with CTCL, including aggressive CTCL entities (transformed mycosis fungoides and CD30-negative large T-cell lymphoma) and an indolent entity (CD30-positive large T-cell lymphoma), were investigated. For genome-wide DNA methylation screening, differential methylation hybridization using CpG island microarrays was applied, which allows simultaneous detection of the methylation status of 8640 CpG islands. Bisulfite sequence analysis was applied for confirmation and detection of hypermethylation of eight selected tumor suppressor genes. The DNA methylation patterns of CTCLs emerging from differential methylation hybridization analysis included 35 CpG islands hypermethylated in at least four of the 28 studied CTCL samples when compared with benign T-cell samples. Hypermethylation of the putative tumor suppressor genes BCL7a (in 48% of CTCL samples), PTPRG (27%), and thrombospondin 4 (52%) was confirmed and demonstrated to be associated with transcriptional downregulation. BCL7a was hypermethylated at a higher frequency in aggressive (64%) than in indolent (14%) CTCL entities. In addition, the promoters of the selected tumor suppressor genes p73 (48%), p16 (33%), CHFR (19%), p15 (10%), and TMS1 (10%) were hypermethylated in CTCL. Malignant T cells of patients with CTCL display widespread promoter hypermethylation associated with inactivation of several tumor suppressor genes involved in DNA repair, cell cycle, and apoptosis signaling pathways. In view of this, CTCL may be amenable to treatment with demethylating agents.

  17. Curcumin induces autophagic cell death in Spodoptera frugiperda cells.

    Science.gov (United States)

    Veeran, Sethuraman; Shu, Benshui; Cui, Gaofeng; Fu, Shengjiao; Zhong, Guohua

    2017-06-01

    The increasing interest in the role of autophagy (type II cell death) in the regulation of insect toxicology has propelled study of investigating autophagic cell death pathways. Turmeric, the rhizome of the herb Curcuma longa (Mañjaḷ in Tamil, India and Jiānghuáng in Chinese) have been traditionally used for the pest control either alone or combination with other botanical pesticides. However, the mechanisms by which Curcuma longa or curcumin exerts cytotoxicity in pests are not well understood. In this study, we investigated the potency of Curcuma longa (curcumin) as a natural pesticide employing Sf9 insect line. Autophagy induction effect of curcumin on Spodoptera frugiperda (Sf9) cells was investigated using various techniques including cell proliferation assay, morphology analysis with inverted phase contrast microscope and Transmission Electron Microscope (TEM) analysis. Autophagy was evaluated using the fluorescent dye monodansylcadaverine (MDC). Cell death measurement was examined using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) within the concentrations of 5-15μg/mL. Curcumin inhibited the growth of the Sf9 cells and induced autophagic cell death in a time and dose dependent manner. Staining the cells with MDC showed the presence of autophagic vacuoles while increased in a dose and time dependent manner. At the ultrastructural level transmission electron microscopy, cells revealed massive autophagy vacuole accumulation and absence of chromatin condensation. Protein expression levels of ATG8-I and ATG8-II, well-established markers of autophagy related protein were elevated in a time dependent manner after curcumin treatment. The present study proves that curcumin induces autophagic cell death in Sf9 insect cell line and this is the first report of cytotoxic effect of curcumin in insect cells and that will be utilized as natural pesticides in future. Copyright © 2017. Published by Elsevier Inc.

  18. Methods for assessing autophagy and autophagic cell death.

    Science.gov (United States)

    Tasdemir, Ezgi; Galluzzi, Lorenzo; Maiuri, M Chiara; Criollo, Alfredo; Vitale, Ilio; Hangen, Emilie; Modjtahedi, Nazanine; Kroemer, Guido

    2008-01-01

    Autophagic (or type 2) cell death is characterized by the massive accumulation of autophagic vacuoles (autophagosomes) in the cytoplasm of cells that lack signs of apoptosis (type 1 cell death). Here we detail and critically assess a series of methods to promote and inhibit autophagy via pharmacological and genetic manipulations. We also review the techniques currently available to detect autophagy, including transmission electron microscopy, half-life assessments of long-lived proteins, detection of LC3 maturation/aggregation, fluorescence microscopy, and colocalization of mitochondrion- or endoplasmic reticulum-specific markers with lysosomal proteins. Massive autophagic vacuolization may cause cellular stress and represent a frustrated attempt of adaptation. In this case, cell death occurs with (or in spite of) autophagy. When cell death occurs through autophagy, on the contrary, the inhibition of the autophagic process should prevent cellular demise. Accordingly, we describe a strategy for discriminating cell death with autophagy from cell death through autophagy.

  19. Can deaths in police cells be prevented? Experience from Norway and death rates in other countries.

    Science.gov (United States)

    Aasebø, Willy; Orskaug, Gunnar; Erikssen, Jan

    2016-01-01

    To describe the changes in death rates and causes of deaths in Norwegian police cells during the last 2 decades. To review reports on death rates in police cells that have been published in medical journals and elsewhere, and discuss the difficulties of comparing death rates between countries. Data on deaths in Norwegian police cells were collected retrospectively in 2002 and 2012 for two time periods: 1993-2001 (period 1) and 2003-2012 (period 2). Several databases were searched to find reports on deaths in police cells from as many countries as possible. The death rates in Norwegian police cells reduced significantly from 0.83 deaths per year per million inhabitants (DYM) in period 1 to 0.22 DYM in period 2 (p police cells reduced by about 75% over a period of approximately 10 years. This is probably mainly due to individuals with severe alcohol intoxication no longer being placed in police cells. However, there remain large methodology difficulties in comparing deaths rates between countries. Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  20. Lysosomal cell death at a glance

    DEFF Research Database (Denmark)

    Aits, Sonja; Jaattela, Marja

    2013-01-01

    Lysosomes serve as the cellular recycling centre and are filled with numerous hydrolases that can degrade most cellular macromolecules. Lysosomal membrane permeabilization and the consequent leakage of the lysosomal content into the cytosol leads to so-called "lysosomal cell death". This form...... of cell death is mainly carried out by the lysosomal cathepsin proteases and can have necrotic, apoptotic or apoptosis-like features depending on the extent of the leakage and the cellular context. This article summarizes our current knowledge on lysosomal cell death with an emphasis on the upstream...... mechanisms that lead to lysosomal membrane permeabilization....

  1. Understanding cell cycle and cell death regulation provides novel weapons against human diseases.

    Science.gov (United States)

    Wiman, K G; Zhivotovsky, B

    2017-05-01

    Cell division, cell differentiation and cell death are the three principal physiological processes that regulate tissue homoeostasis in multicellular organisms. The growth and survival of cells as well as the integrity of the genome are regulated by a complex network of pathways, in which cell cycle checkpoints, DNA repair and programmed cell death have critical roles. Disruption of genomic integrity and impaired regulation of cell death may both lead to uncontrolled cell growth. Compromised cell death can also favour genomic instability. It is becoming increasingly clear that dysregulation of cell cycle and cell death processes plays an important role in the development of major disorders such as cancer, cardiovascular disease, infection, inflammation and neurodegenerative diseases. Research achievements in these fields have led to the development of novel approaches for treatment of various conditions associated with abnormalities in the regulation of cell cycle progression or cell death. A better understanding of how cellular life-and-death processes are regulated is essential for this development. To highlight these important advances, the Third Nobel Conference entitled 'The Cell Cycle and Cell Death in Disease' was organized at Karolinska Institutet in 2016. In this review we will summarize current understanding of cell cycle progression and cell death and discuss some of the recent advances in therapeutic applications in pathological conditions such as cancer, neurological disorders and inflammation. © 2017 The Association for the Publication of the Journal of Internal Medicine.

  2. The tumor suppressor PTEN inhibits EGF-induced TSP-1 and TIMP-1 expression in FTC-133 thyroid carcinoma cells

    International Nuclear Information System (INIS)

    Soula-Rothhut, Mahdhia; Coissard, Cyrille; Sartelet, Herve; Boudot, Cedric; Bellon, Georges; Martiny, Laurent; Rothhut, Bernard

    2005-01-01

    Thrombospondin-1 (TSP-1) is a multidomain extracellular macromolecule that was first identified as natural modulator of angiogenesis and tumor growth. In the present study, we found that epidermal growth factor (EGF) up-regulated TSP-1 expression in FTC-133 (primary tumor) but not in FTC-238 (lung metastasis) thyroid cancer cells. Both EGF and TSP-1 induced expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) in a mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) and phosphatidylinositol 3-kinase (PI3-kinase)-dependent manner. In FTC-133 cells, EGF induced proliferation in a TSP-1- and TIMP-1-dependent manner. In addition, we determined that re-expression of the tumor suppressor protein PTEN induced cell death, an effect that correlated with a block of Akt kinase phosphorylation. EGF-induced TSP-1 and TIMP-1 promoter activity and protein expression were inhibited in FTC-133 cells stably expressing wtPTEN but not in cells expressing mutant PTEN. Furthermore, we found that wtPTEN inhibited EGF-but not TSP-1-stimulated FTC-133 cell migration and also inhibited invasion induced by EGF and by TSP-1. Finally, an antibody against TSP-1 reversed EGF-stimulated FTC-133 cell invasion as well as the constitutive invasive potential of FTC-238 cells. Overall, our results suggest that PTEN can function as an important modulator of extracellular matrix proteins in thyroid cancer. Therefore, analyzing differential regulation of TSP-1 by growth factors such as EGF can be helpful in understanding thyroid cancer development

  3. BID links ferroptosis to mitochondrial cell death pathways

    Directory of Open Access Journals (Sweden)

    Sandra Neitemeier

    2017-08-01

    Full Text Available Ferroptosis has been defined as an oxidative and iron-dependent pathway of regulated cell death that is distinct from caspase-dependent apoptosis and established pathways of death receptor-mediated regulated necrosis. While emerging evidence linked features of ferroptosis induced e.g. by erastin-mediated inhibition of the Xc- system or inhibition of glutathione peroxidase 4 (Gpx4 to an increasing number of oxidative cell death paradigms in cancer cells, neurons or kidney cells, the biochemical pathways of oxidative cell death remained largely unclear. In particular, the role of mitochondrial damage in paradigms of ferroptosis needs further investigation.In the present study, we find that erastin-induced ferroptosis in neuronal cells was accompanied by BID transactivation to mitochondria, loss of mitochondrial membrane potential, enhanced mitochondrial fragmentation and reduced ATP levels. These hallmarks of mitochondrial demise are also established features of oxytosis, a paradigm of cell death induced by Xc- inhibition by millimolar concentrations of glutamate. Bid knockout using CRISPR/Cas9 approaches preserved mitochondrial integrity and function, and mediated neuroprotective effects against both, ferroptosis and oxytosis. Furthermore, the BID-inhibitor BI-6c9 inhibited erastin-induced ferroptosis, and, in turn, the ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 prevented mitochondrial dysfunction and cell death in the paradigm of oxytosis. These findings show that mitochondrial transactivation of BID links ferroptosis to mitochondrial damage as the final execution step in this paradigm of oxidative cell death. Keywords: Ferroptosis, BID, Mitochondria, CRISPR, Oxytosis, Neuronal death

  4. Clinical Impact of the Immunome in Lymphoid Malignancies: The Role of Myeloid-Derived Suppressor Cells

    Science.gov (United States)

    Vetro, Calogero; Romano, Alessandra; Ancora, Flavia; Coppolino, Francesco; Brundo, Maria V.; Raccuia, Salvatore A.; Puglisi, Fabrizio; Tibullo, Daniele; La Cava, Piera; Giallongo, Cesarina; Parrinello, Nunziatina L.

    2015-01-01

    The better definition of the mutual sustainment between neoplastic cells and immune system has been translated from the bench to the bedside acquiring value as prognostic factor. Additionally, it represents a promising tool for improving therapeutic strategies. In this context, myeloid-derived suppressor cells (MDSCs) have gained a central role in tumor developing with consequent therapeutic implications. In this review, we will focus on the biological and clinical impact of the study of MDSCs in the settings of lymphoid malignancies. PMID:26052505

  5. Genomic Analyses Reveal Global Functional Alterations That Promote Tumor Growth and Novel Tumor Suppressor Genes in Natural Killer-Cell Malignancies

    DEFF Research Database (Denmark)

    Kucuk, Can; Iqbal, Javeed; J. deLeeuw, Ronald

    in cell proliferation, growth and energy metabolic processes important for the neoplastic cells. In deleted regions, genes showing decreased expression included transcription factors or repressors (e.g. SP4, PRDM1, NCOR1 and ZNF10), tumor suppressors or negative regulators of the cell cycle (e.g. CDKN2C...

  6. The control and execution of programmed cell death

    International Nuclear Information System (INIS)

    Begum, R.; Pathak, N.; Hasnain, S.E.; Sah, N.K.; Athar, M.

    1999-01-01

    Apoptosis or programmed cell death is a highly conserved genetically controlled response of metazoan cells to commit suicide. Non apoptotic programmed cell death seems to operate in single celled eukaryotes implying that evolution of PCD has preceded the evolution of multicellularity. PCD plays a crucial role in the regulation of cellular and tissue homeostasis and any aberrations in apoptosis leads to several diseases including cancer, neurodegenerative disorders and AIDS. The mechanisms by which apoptosis is controlled are varied. In some cells, members of bcl-2 family or p53 are crucial for regulating the apoptosis programme, whereas in other cells Fas ligand is more important. bcl-2 family members have a prime role in the regulation of cell death at all stages including development, whereas cell death during development is independent of p53. bcl-2 family members being localized on the outer mitochondrial membrane, control the mitochondrial homeostasis and cytochrome c redistribution and thereby regulate the cell death process. p53 promotes DNA damage mediated cell death after growth arrest and failed DNA repair. Caspases play a key role in the execution of cell death by mediating highly specific cleavages of crucial cellular proteins collectively manifesting the apoptotic phenotype. Protein inhibitors like crm A, p35 and IAPs could prevent/control apoptosis induced by a broad array of cell death stimuli by several mechanisms specially interfering in caspase activation or caspase activity. Among endonucleases, caspase activated DNase (CAD) plays a crucial role in DNA fragmentation, a biochemical hallmark of apoptosis. As regulation of cell death seems to be as complex as regulation of cell proliferation, multiple kinase mediated regulatory mechanisms might control the apoptotic process. Thus, in spite of intensive research over the past few years, the field of apoptosis still remains fertile to unravel among others, the molecular mechanisms of cytochrome c

  7. The control and execution of programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    Begum, R.; Pathak, N.; Hasnain, S.E.; Sah, N.K. [National Inst. of Immunology, New Delhi (India). Eukaryotic Gene Expression Lab.; Taneja, T.K.; Mohan, M. [National Inst. of Immunology, New Delhi (India). Eukaryotic Gene Expression Lab.]|[Dept. of Medical Elementology and Toxicology, New Delhi (India); Athar, M. [Dept. of Medical Elementology and Toxicology, New Delhi (India)

    1999-07-01

    Apoptosis or programmed cell death is a highly conserved genetically controlled response of metazoan cells to commit suicide. Non apoptotic programmed cell death seems to operate in single celled eukaryotes implying that evolution of PCD has preceded the evolution of multicellularity. PCD plays a crucial role in the regulation of cellular and tissue homeostasis and any aberrations in apoptosis leads to several diseases including cancer, neurodegenerative disorders and AIDS. The mechanisms by which apoptosis is controlled are varied. In some cells, members of bcl-2 family or p53 are crucial for regulating the apoptosis programme, whereas in other cells Fas ligand is more important. bcl-2 family members have a prime role in the regulation of cell death at all stages including development, whereas cell death during development is independent of p53. bcl-2 family members being localized on the outer mitochondrial membrane, control the mitochondrial homeostasis and cytochrome c redistribution and thereby regulate the cell death process. p53 promotes DNA damage mediated cell death after growth arrest and failed DNA repair. Caspases play a key role in the execution of cell death by mediating highly specific cleavages of crucial cellular proteins collectivley manifesting the apoptotic phenotype. Protein inhibitors like crm A, p35 and IAPs could prevent/control apoptosis induced by a broad array of cell death stimuli by several mechanisms specially interfering in caspase activation or caspase activity. Among endonucleases, caspase activated DNase (CAD) plays a crucial role in DNA fragmentation, a biochemical hallmark of apoptosis. As regulation of cell death seems to be as complex as regulation of cell proliferation, multiple kinase mediated regulatory mechanisms might control the apoptotic process. Thus, in spite of intensive research over the past few years, the field of apoptosis still remains fertile to unravel among others, the molecular mechanisms of cytochrome c

  8. Mitochondrial fission proteins regulate programmed cell death in yeast

    OpenAIRE

    Fannjiang, Yihru; Cheng, Wen-Chih; Lee, Sarah J.; Qi, Bing; Pevsner, Jonathan; McCaffery, J. Michael; Hill, R. Blake; Basañez, Gorka; Hardwick, J. Marie

    2004-01-01

    The possibility that single-cell organisms undergo programmed cell death has been questioned in part because they lack several key components of the mammalian cell death machinery. However, yeast encode a homolog of human Drp1, a mitochondrial fission protein that was shown previously to promote mammalian cell death and the excessive mitochondrial fragmentation characteristic of apoptotic mammalian cells. In support of a primordial origin of programmed cell death involving mitochondria, we fo...

  9. Retinal Cell Death Caused by Sodium Iodate Involves Multiple Caspase-Dependent and Caspase-Independent Cell-Death Pathways

    Directory of Open Access Journals (Sweden)

    Jasmin Balmer

    2015-07-01

    Full Text Available Herein, we have investigated retinal cell-death pathways in response to the retina toxin sodium iodate (NaIO3 both in vivo and in vitro. C57/BL6 mice were treated with a single intravenous injection of NaIO3 (35 mg/kg. Morphological changes in the retina post NaIO3 injection in comparison to untreated controls were assessed using electron microscopy. Cell death was determined by TdT-mediated dUTP-biotin nick end labeling (TUNEL staining. The activation of caspases and calpain was measured using immunohistochemistry. Additionally, cytotoxicity and apoptosis in retinal pigment epithelial (RPE cells, primary retinal cells, and the cone photoreceptor (PRC cell line 661W were assessed in vitro after NaIO3 treatment using the ApoToxGlo™ assay. The 7-AAD/Annexin-V staining was performed and necrostatin (Nec-1 was administered to the NaIO3-treated cells to confirm the results. In vivo, degenerating RPE cells displayed a rounded shape and retracted microvilli, whereas PRCs featured apoptotic nuclei. Caspase and calpain activity was significantly upregulated in retinal sections and protein samples from NaIO3-treated animals. In vitro, NaIO3 induced necrosis in RPE cells and apoptosis in PRCs. Furthermore, Nec-1 significantly decreased NaIO3-induced RPE cell death, but had no rescue effect on treated PRCs. In summary, several different cell-death pathways are activated in retinal cells as a result of NaIO3.

  10. Cell death induced by hydroxyapatite on L929 fibroblast cells.

    Science.gov (United States)

    Inayat-Hussain, S H; Rajab, N F; Roslie, H; Hussin, A A; Ali, A M; Annuar, B O

    2004-05-01

    Biomaterials intended for end-use application as bone-graft substitutes have to undergo safety evaluation. In this study, we investigated the in vitro cytotoxic effects especially to determine the mode of death of two hydroxyapatite compounds (HA2, HA3) which were synthesized locally. The methods used for cytotoxicity was the standard MTT assay whereas AO/PI staining was performed to determine the mode of cell death in HA treated L929 fibroblasts. Our results demonstrated that both HA2 and HA3 were not significantly cytotoxic as more than 75% cells after 72 hours treatment were viable. Furthermore, we found that the major mode of cell death in HA treated cells was apoptosis. In conclusion, our results demonstrated that these hydroxyapatite compounds are not cytotoxic where the mode of death was primarily via apoptosis.

  11. Multi-gene epigenetic silencing of tumor suppressor genes in T-cell lymphoma cells; delayed expression of the p16 protein upon reversal of the silencing

    DEFF Research Database (Denmark)

    Nagasawa, T; Zhang, Q; Raghunath, P N

    2006-01-01

    To understand better T-cell lymphomagenesis, we examined promoter CpG methylation and mRNA expression of closely related genes encoding p16, p15, and p14 tumor suppressor genes in cultured malignant T-cells that were derived from cutaneous, adult type, and anaplastic lymphoma kinase (ALK)-express...

  12. Significance of apoptotic cell death after γ-irradiation

    International Nuclear Information System (INIS)

    Wu, H.G.; Kim, I.H.; Ha, S.W.; Park, C.I.

    2003-01-01

    Full text: The objectives of this study are to investigate the significance of apoptotic death compared to total cell death after γ-ray irradiation in human Hand N cancer cell lines and to find out correlation between apoptosis and radiation sensitivity. Materials and Method: Head and neck cancer cell lines (PCI-1, PCI-13, and SNU-1066), leukemia cell line (CCRF-CEM), and fibroblast cell line (LM217) as a normal control were used for this study. Cells were irradiated using Cs-137 animal experiment irradiator. Total cell death was measured by clonogenic assay. Annexin-V staining was used to detect the fraction of apoptotic death. The resulting data was analyzed with two parameters, apoptotic index (AI) and apoptotic fraction(AF). AI is ratio of apoptotic cells to total cells, and AF is ration of apoptotic cell death to mutant frequencytion ex(Number of apoptotic cells) / (Number of total cells counted) AF = {(AI) / (1-survival fraction)} x 100 (%) Results. Surviving fraction at 2 Gy (SF2) were 0.741, 0.544, 0.313, 0.302, and 0.100 for PCI-1, PCI-13, SNU-1066, CCRF-CEM, and LM217 cell lines, respectively. Apoptosis was detected in all cell lines. Apoptotic index reached peak value at 72 hours after irradiation in head and neck cancer cell lines, and that was at 24 hours in CCRF-CEM and LM217. Total cell death increased exponentially with increasing radiation dose from 0 Gy to 8 Gy, but the change was minimal in apoptotic index (Fig. 1.). Apoptotic fractions at 2 Gy were 46%, 48%, 46%, 24%, and 19% and at 6 Gy were 20%, 33%, 35%, 17%, and 20% for PCI-1, PCI-13, SNU-1066, CCRF-CEM, and LM217, respectively. The radioresistant cell lines showed more higher apoptotic fraction at 2 Gy (Table 1.), but there was not such correlation at 6 Gy. Conclusion: All cell lines used in this study showed apoptosis after irradiation, but time course of apoptosis was different from that of leukemia cell line and normal fibroblast cell line. Reproductive cell death was more important

  13. The slow cell death response when screening chemotherapeutic agents.

    Science.gov (United States)

    Blois, Joseph; Smith, Adam; Josephson, Lee

    2011-09-01

    To examine the correlation between cell death and a common surrogate of death used in screening assays, we compared cell death responses to those obtained with the sulforhodamine B (SRB) cell protein-based "cytotoxicity" assay. With the SRB assay, the Hill equation was used to obtain an IC50 and final cell mass, or cell mass present at infinite agent concentrations, with eight adherent cell lines and four agents (32 agent/cell combinations). Cells were treated with high agent concentrations (well above the SRB IC50) and the death response determined as the time-dependent decrease in cells failing to bind both annexin V and vital fluorochromes by flow cytometry. Death kinetics were categorized as fast (5/32) (similar to the reference nonadherent Jurkat line), slow (17/32), or none (10/32), despite positive responses in the SRB assay in all cases. With slow cell death, a single exposure to a chemotherapeutic agent caused a slow, progressive increase in dead (necrotic) and dying (apoptotic) cells for at least 72 h. Cell death (defined by annexin and/or fluorochrome binding) did not correlate with the standard SRB "cytotoxicity" assay. With the slow cell death response, a single exposure to an agent caused a slow conversion from vital to apoptotic and necrotic cells over at least 72 h (the longest time point examined). Here, increasing the time of exposure to agent concentrations modestly above the SRB IC50 provides a method of maximizing cell kill. If tumors respond similarly, sustained low doses of chemotherapeutic agents, rather than a log-kill, maximum tolerated dose strategy may be an optimal strategy of maximizing tumor cell death.

  14. Ionizing radiation-induced cell death

    International Nuclear Information System (INIS)

    Szumiel, I.

    1994-01-01

    Selected aspects of radiation-induced cell death, connected with signal transduction pathways are reviewed. Cell death is defined as insufficiency of the cellular signal transducing system to maintain the cell's physiological functions. The insufficiency may be due to impaired signal reception and/or transduction, lack or erroneous transcription activation, and eventual cellular ''misexpression'' of the signal. The molecular basis of this insufficiency would be damage to genomic (but also other cellular) structures and closing of specific signalling pathways or opening of others (like those leading to apoptosis). I describe experimental data that suggest an important role of RAS/NFI and p53/p105 Rb proteins in cell cycle control-coupled responses to DNA damage. (Author)

  15. Infrared suppressor effect on T63 turboshaft engine performance

    Science.gov (United States)

    Bailey, E. E.; Civinskas, K. C.; Walker, C. L.

    1978-01-01

    Tests were conducted to determine if there are performance penalties associated with the installation of infrared (IR) suppressors on the T63-A-700 turboshaft engine. The testing was done in a sea-level, static test cell. The same engine (A-E402808 B) was run with the standard OH-58 aircraft exhaust stacks and with the ejector-type IR suppressors in order to make a valid comparison. Repeatability of the test results for the two configurations was verified by rerunning the conditions over a period of days. Test results showed no measurable difference in performance between the standard exhaust stacks and the IR suppressors.

  16. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids....... However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death...... occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development...

  17. The anti-cell death FNK protein protects cells from death induced by freezing and thawing

    International Nuclear Information System (INIS)

    Sudo, Kentaro; Asoh, Sadamitsu; Ohsawa, Ikuroh; Ozaki, Daiya; Yamagata, Kumi; Ito, Hiromoto; Ohta, Shigeo

    2005-01-01

    The FNK protein, constructed from anti-apoptotic Bcl-x L with enhanced activity, was fused with the protein transduction domain (PTD) of the HIV/Tat protein to mediate the delivery of FNK into cells. The fusion protein PTD-FNK was introduced into chondrocytes in isolated articular cartilage-bone sections, cultured neurons, and isolated bone marrow mononuclear cells to evaluate its ability to prevent cell death induced by freezing and thawing. PTD-FNK protected the cells from freeze-thaw damage in a concentration-dependent manner. Addition of PTD-FNK with conventional cryoprotectants (dimethyl sulfoxide and hydroxyethyl starch) increased surviving cell numbers around 2-fold compared with controls treated only with the cryoprotectants. Notably, PTD-FNK allowed CD34 + cells among bone marrow mononuclear cells to survive more efficiently (12-fold more than the control cells) from two successive freeze-thaw cycles. Thus, PTD-FNK prevented cell death induced by freezing and thawing, suggesting that it provides for the successful cryopreservation of biological materials

  18. Characterization of cell-surface receptors for monoclonal-nonspecific suppressor factor (MNSF)

    International Nuclear Information System (INIS)

    Nakamura, M.; Ogawa, H.; Tsunematsu, T.

    1990-01-01

    Monoclonal-nonspecific suppressor factor (MNSF) is a lymphokine derived from murine T cell hybridoma. The target tissues are both LPS-stimulated B cells and Con A-stimulated T cells. Since the action of MNSF may be mediated by its binding to specific cell surface receptors, we characterized the mode of this binding. The purified MNSF was labeled with 125 I, using the Bolton-Hunter reagent. The labeled MNSF bound specifically to a single class of receptor (300 receptors per cell) on mitogen-stimulated murine B cells or T cells with an affinity of 16 pM at 24 degrees C, in the presence of sodium azide. Competitive experiments showed that MNSF bound to the specific receptor and that the binding was not shared with IL2, IFN-gamma, and TNF. Various cell types were surveyed for the capacity to specifically bind 125 I-MNSF. 125 I-MNSF bound to MOPC-31C (a murine plasmacytoma line) and to EL4 (a murine T lymphoma line). The presence of specific binding correlates with the capacity of the cells to respond to MNSF. These data support the view that like other polypeptide hormones, the action of MNSF is mediated by specific cell surface membrane receptor protein. Identification of these receptors will provide insight into the apparently diverse activities of MNSF

  19. Mechanisms of Betulinic acid‐induced cell death

    NARCIS (Netherlands)

    Potze, L.

    2015-01-01

    The scope of this thesis was to investigate the mechanisms by which BetA induces cell death in cancer cells in more detail. At the start of the studies described in this thesis several questions urgently needed an answer. Although BetA induces cell death via apoptosis, when blocking this form of

  20. BID links ferroptosis to mitochondrial cell death pathways.

    Science.gov (United States)

    Neitemeier, Sandra; Jelinek, Anja; Laino, Vincenzo; Hoffmann, Lena; Eisenbach, Ina; Eying, Roman; Ganjam, Goutham K; Dolga, Amalia M; Oppermann, Sina; Culmsee, Carsten

    2017-08-01

    Ferroptosis has been defined as an oxidative and iron-dependent pathway of regulated cell death that is distinct from caspase-dependent apoptosis and established pathways of death receptor-mediated regulated necrosis. While emerging evidence linked features of ferroptosis induced e.g. by erastin-mediated inhibition of the X c - system or inhibition of glutathione peroxidase 4 (Gpx4) to an increasing number of oxidative cell death paradigms in cancer cells, neurons or kidney cells, the biochemical pathways of oxidative cell death remained largely unclear. In particular, the role of mitochondrial damage in paradigms of ferroptosis needs further investigation. In the present study, we find that erastin-induced ferroptosis in neuronal cells was accompanied by BID transactivation to mitochondria, loss of mitochondrial membrane potential, enhanced mitochondrial fragmentation and reduced ATP levels. These hallmarks of mitochondrial demise are also established features of oxytosis, a paradigm of cell death induced by X c - inhibition by millimolar concentrations of glutamate. Bid knockout using CRISPR/Cas9 approaches preserved mitochondrial integrity and function, and mediated neuroprotective effects against both, ferroptosis and oxytosis. Furthermore, the BID-inhibitor BI-6c9 inhibited erastin-induced ferroptosis, and, in turn, the ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 prevented mitochondrial dysfunction and cell death in the paradigm of oxytosis. These findings show that mitochondrial transactivation of BID links ferroptosis to mitochondrial damage as the final execution step in this paradigm of oxidative cell death. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  1. The Heterologous Expression of the p22 RNA Silencing Suppressor of the Crinivirus Tomato Chlorosis Virus from Tobacco Rattle Virus and Potato Virus X Enhances Disease Severity but Does Not Complement Suppressor-Defective Mutant Viruses.

    Science.gov (United States)

    Landeo-Ríos, Yazmín; Navas-Castillo, Jesús; Moriones, Enrique; Cañizares, M. Carmen

    2017-11-24

    To counteract host antiviral RNA silencing, plant viruses express suppressor proteins that function as pathogenicity enhancers. The genome of the Tomato chlorosis virus (ToCV) (genus Crinivirus , family Closteroviridae ) encodes an RNA silencing suppressor, the protein p22, that has been described as having one of the longest lasting local suppressor activities when assayed in Nicotiana benthamiana . Since suppression of RNA silencing and the ability to enhance disease severity are closely associated, we analyzed the effect of expressing p22 in heterologous viral contexts. Thus, we studied the effect of the expression of ToCV p22 from viral vectors Tobacco rattle virus (TRV) and Potato virus X (PVX), and from attenuated suppressor mutants in N. benthamiana plants. Our results show that although an exacerbation of disease symptoms leading to plant death was observed in the heterologous expression of ToCV p22 from both viruses, only in the case of TRV did increased viral accumulation occur. The heterologous expression of ToCV p22 could not complement suppressor-defective mutant viruses.

  2. Caspase-independent cell death mediated by apoptosis-inducing factor (AIF) nuclear translocation is involved in ionizing radiation induced HepG2 cell death

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hengwen [Department of Radiation, Cancer Center of Guangdong General Hospital (Guangdong Academy of Medical Science), Guangzhou, 510080, Guangdong (China); Yang, Shana; Li, Jianhua [Department of Physiology, Guangzhou Medical University, Guangzhou, 510182, Guangdong (China); Zhang, Yajie [Department of Pathology, Guangzhou Medical University, Guangzhou, 510182, Guangdong (China); Gao, Dongsheng [Department of Oncology, Guangdong Medical College Affiliated Pengpai Memorial Hospital, Hai Feng, 516400, Gungdong (China); Zhao, Shenting, E-mail: zhaoshenting@126.com [Department of Physiology, Guangzhou Medical University, Guangzhou, 510182, Guangdong (China)

    2016-03-25

    Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. The aim of radiotherapy is to eradicate cancer cells with ionizing radiation. Except for the caspase-dependent mechanism, several lines of evidence demonstrated that caspase-independent mechanism is directly involved in the cell death responding to irradiation. For this reason, defining the contribution of caspase-independent molecular mechanisms represents the main goal in radiotherapy. In this study, we focused on the role of apoptosis-inducing factor (AIF), the caspase-independent molecular, in ionizing radiation induced hepatocellular carcinoma cell line (HepG2) cell death. We found that ionizing radiation has no function on AIF expression in HepG2 cells, but could induce AIF release from the mitochondria and translocate into nuclei. Inhibition of AIF could reduce ionizing radiation induced HepG2 cell death. These studies strongly support a direct relationship between AIF nuclear translocation and radiation induced cell death. What's more, AIF nuclear translocation is caspase-independent manner, but not caspase-dependent manner, in this process. These new findings add a further attractive point of investigation to better define the complex interplay between caspase-independent cell death and radiation therapy. - Highlights: • AIF nuclear translocation is involved in ionizing radiation induced hepatocellular carcinoma cell line HepG2 cell death. • AIF mediated cell death induced by ionizing radiation is caspase-independent. • Caspase-independent pathway is involved in ionzing radiation induced HepG2 cell death.

  3. Caspase-independent cell death mediated by apoptosis-inducing factor (AIF) nuclear translocation is involved in ionizing radiation induced HepG2 cell death

    International Nuclear Information System (INIS)

    Sun, Hengwen; Yang, Shana; Li, Jianhua; Zhang, Yajie; Gao, Dongsheng; Zhao, Shenting

    2016-01-01

    Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. The aim of radiotherapy is to eradicate cancer cells with ionizing radiation. Except for the caspase-dependent mechanism, several lines of evidence demonstrated that caspase-independent mechanism is directly involved in the cell death responding to irradiation. For this reason, defining the contribution of caspase-independent molecular mechanisms represents the main goal in radiotherapy. In this study, we focused on the role of apoptosis-inducing factor (AIF), the caspase-independent molecular, in ionizing radiation induced hepatocellular carcinoma cell line (HepG2) cell death. We found that ionizing radiation has no function on AIF expression in HepG2 cells, but could induce AIF release from the mitochondria and translocate into nuclei. Inhibition of AIF could reduce ionizing radiation induced HepG2 cell death. These studies strongly support a direct relationship between AIF nuclear translocation and radiation induced cell death. What's more, AIF nuclear translocation is caspase-independent manner, but not caspase-dependent manner, in this process. These new findings add a further attractive point of investigation to better define the complex interplay between caspase-independent cell death and radiation therapy. - Highlights: • AIF nuclear translocation is involved in ionizing radiation induced hepatocellular carcinoma cell line HepG2 cell death. • AIF mediated cell death induced by ionizing radiation is caspase-independent. • Caspase-independent pathway is involved in ionzing radiation induced HepG2 cell death.

  4. Isoform-specific interactions of the von Hippel-Lindau tumor suppressor protein

    OpenAIRE

    Minervini, Giovanni; Mazzotta, Gabriella M.; Masiero, Alessandro; Sartori, Elena; Corr?, Samantha; Potenza, Emilio; Costa, Rodolfo; Tosatto, Silvio C. E.

    2015-01-01

    Deregulation of the von Hippel-Lindau tumor suppressor protein (pVHL) is considered one of the main causes for malignant renal clear-cell carcinoma (ccRCC) insurgence. In human, pVHL exists in two isoforms, pVHL19 and pVHL30 respectively, displaying comparable tumor suppressor abilities. Mutations of the p53 tumor suppressor gene have been also correlated with ccRCC insurgence and ineffectiveness of treatment. A recent proteomic analysis linked full length pVHL30 with p53 pathway regulation t...

  5. The regulation of apoptotic cell death

    Directory of Open Access Journals (Sweden)

    Amarante-Mendes G.P.

    1999-01-01

    Full Text Available Apoptosis is a fundamental biological phenomenon in which the death of a cell is genetically and biochemically regulated. Different molecules are involved in the regulation of the apoptotic process. Death receptors, coupled to distinct members of the caspases as well as other adapter molecules, are involved in the initiation of the stress signals (The Indictment. Members of the Bcl-2 family control at the mitochondrial level the decision between life and death (The Judgement. The effector caspases are responsible for all morphological and biochemical changes related to apoptosis including the "eat-me" signals perceived by phagocytes and neighboring cells (The Execution. Finally, apoptosis would have little biological significance without the recognition and removal of the dying cells (The Burial.

  6. Metastasis suppressor proteins in cutaneous squamous cell carcinoma.

    Science.gov (United States)

    Bozdogan, Onder; Vargel, Ibrahim; Cavusoglu, Tarik; Karabulut, Ayse A; Karahan, Gurbet; Sayar, Nilufer; Atasoy, Pınar; Yulug, Isik G

    2016-07-01

    Cutaneous squamous cell carcinomas (cSCCs) are common human carcinomas. Despite having metastasizing capacities, they usually show less aggressive progression compared to squamous cell carcinoma (SCC) of other organs. Metastasis suppressor proteins (MSPs) are a group of proteins that control and slow-down the metastatic process. In this study, we established the importance of seven well-defined MSPs including NDRG1, NM23-H1, RhoGDI2, E-cadherin, CD82/KAI1, MKK4, and AKAP12 in cSCCs. Protein expression levels of the selected MSPs were detected in 32 cSCCs, 6 in situ SCCs, and two skin cell lines (HaCaT, A-431) by immunohistochemistry. The results were evaluated semi-quantitatively using the HSCORE system. In addition, mRNA expression levels were detected by qRT-PCR in the cell lines. The HSCOREs of NM23-H1 were similar in cSCCs and normal skin tissues, while RGHOGDI2, E-cadherin and AKAP12 were significantly downregulated in cSCCs compared to normal skin. The levels of MKK4, NDRG1 and CD82 were partially conserved in cSCCs. In stage I SCCs, nuclear staining of NM23-H1 (NM23-H1nuc) was significantly lower than in stage II/III SCCs. Only nuclear staining of MKK4 (MKK4nuc) showed significantly higher scores in in situ carcinomas compared to invasive SCCs. In conclusion, similar to other human tumors, we have demonstrated complex differential expression patterns for the MSPs in in-situ and invasive cSCCs. This complex MSP signature warrants further biological and experimental pathway research. Copyright © 2016 Elsevier GmbH. All rights reserved.

  7. Ayanin diacetate-induced cell death is amplified by TRAIL in human leukemia cells

    International Nuclear Information System (INIS)

    Marrero, María Teresa; Estévez, Sara; Negrín, Gledy; Quintana, José; López, Mariana; Pérez, Francisco J.; Triana, Jorge; León, Francisco; Estévez, Francisco

    2012-01-01

    Highlights: ► Ayanin diacetate as apoptotic inducer in leukemia cells. ► Cell death was prevented by caspase inhibitors and by the overexpression of Bcl-x L . ► The intrinsic and the extrinsic pathways are involved in the mechanism of action. ► Death receptors are up-regulated and TRAIL enhances apoptotic cell death. -- Abstract: Here we demonstrate that the semi-synthetic flavonoid ayanin diacetate induces cell death selectively in leukemia cells without affecting the proliferation of normal lymphocytes. Incubation of human leukemia cells with ayanin diacetate induced G 2 -M phase cell cycle arrest and apoptosis which was prevented by the non-specific caspase inhibitor z-VAD-fmk and reduced by the overexpression of Bcl-x L . Ayanin diacetate-induced cell death was found to be associated with: (i) loss of inner mitochondrial membrane potential, (ii) the release of cytochrome c, (iii) the activation of multiple caspases, (iv) cleavage of poly(ADP-ribose) polymerase and (v) the up-regulation of death receptors for TRAIL, DR4 and DR5. Moreover, the combined treatment with ayanin diacetate and TRAIL amplified cell death, compared to single treatments. These results provide a basis for further exploring the potential applications of this combination for the treatment of cancer.

  8. Expression of arf tumor suppressor in spermatogonia facilitates meiotic progression in male germ cells.

    Directory of Open Access Journals (Sweden)

    Michelle L Churchman

    2011-07-01

    Full Text Available The mammalian Cdkn2a (Ink4a-Arf locus encodes two tumor suppressor proteins (p16(Ink4a and p19(Arf that respectively enforce the anti-proliferative functions of the retinoblastoma protein (Rb and the p53 transcription factor in response to oncogenic stress. Although p19(Arf is not normally detected in tissues of young adult mice, a notable exception occurs in the male germ line, where Arf is expressed in spermatogonia, but not in meiotic spermatocytes arising from them. Unlike other contexts in which the induction of Arf potently inhibits cell proliferation, expression of p19(Arf in spermatogonia does not interfere with mitotic cell division. Instead, inactivation of Arf triggers germ cell-autonomous, p53-dependent apoptosis of primary spermatocytes in late meiotic prophase, resulting in reduced sperm production. Arf deficiency also causes premature, elevated, and persistent accumulation of the phosphorylated histone variant H2AX, reduces numbers of chromosome-associated complexes of Rad51 and Dmc1 recombinases during meiotic prophase, and yields incompletely synapsed autosomes during pachynema. Inactivation of Ink4a increases the fraction of spermatogonia in S-phase and restores sperm numbers in Ink4a-Arf doubly deficient mice but does not abrogate γ-H2AX accumulation in spermatocytes or p53-dependent apoptosis resulting from Arf inactivation. Thus, as opposed to its canonical role as a tumor suppressor in inducing p53-dependent senescence or apoptosis, Arf expression in spermatogonia instead initiates a salutary feed-forward program that prevents p53-dependent apoptosis, contributing to the survival of meiotic male germ cells.

  9. Epigenetic silencing of MAL, a putative tumor suppressor gene, can contribute to human epithelium cell carcinoma

    Directory of Open Access Journals (Sweden)

    Zhang Jun

    2010-11-01

    Full Text Available Abstract Background To identify new and useful candidate biomarkers in head and neck squamous cell carcinoma (HNSCC, we performed a genome-wide survey and found that Myelin and lymphocyte-associated protein (MAL was a gene that was markedly down-regulated in HNSCC. Hence, we investigated the mechanism of MAL silencing and the effects of MAL on the proliferation, invasion, and apoptotic potential in HNSCC. Results MAL was significantly down-regulated in 91.7% of HNSCC specimens at the mRNA level as compared with adjacent normal tissues (P = 0.0004. Moreover, the relative transcript levels of the MAL gene were remarkably decreased by five-fold in nine HNSCC cell lines as compared with normal head and neck epithelium cells. MAL gene expression was restored in 44%, 67%, and 89% in HNSCC cell lines treated with TSA, 5-Aza-dC, and TSA plus 5-Aza-dC, respectively. Furthermore, bisulfate-treated DNA sequencing demonstrated that the two CpG islands (that is, M1 and M2 located in MAL promoter region were completely methylated in the HNSCC cell lines (CpG methylated ratio was more than 90%, and only one CpG island (that is, M1 was partially methylated in HNSCC tissues (CpG methylated ratio between 20% and 90%. A significant reduction in cell proliferation and a change in the cell cycle profile were also observed in MAL transfectants. Matrigel assay demonstrated that the invasiveness of HNSCC cells significantly decreased. A significant increase in the population of apoptotic cells was observed in MAL transfected cells. The exogenous expression of the MAL gene suppressed malignant phenotypes, while the cell death induced by MAL gene transfer was a result of apoptosis as demonstrated by the induction of cleavage of the poly (that is, ADP-ribose polymerase. Additionally, tumor growth was suppressed in cells expressing MAL as compared with cells not expressing MAL. Conclusion Our data suggest that the epigenetic inactivation of MAL, as a candidate tumor

  10. Myeloid derived suppressor cells (MDSCs are increased and exert immunosuppressive activity together with polymorphonuclear leukocytes (PMNs in chronic myeloid leukemia patients.

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    Cesarina Giallongo

    Full Text Available Tumor immune tolerance can derive from the recruitment of suppressor cell population, including myeloid derived suppressor cells (MDSCs, able to inhibit T cells activity. We identified a significantly expanded MDSCs population in chronic myeloid leukemia (CML patients at diagnosis that decreased to normal levels after imatinib therapy. In addition, expression of arginase 1 (Arg1 that depletes microenvironment of arginine, an essential aminoacid for T cell function, resulted in an increase in patients at diagnosis. Purified CML CD11b+CD33+CD14-HLADR- cells markedly suppressed normal donor T cell proliferation in vitro. Comparing CML Gr-MDSCs to autologous polymorphonuclear leukocytes (PMNs we observed a higher Arg1 expression and activity in PMNs, together with an inhibitory effect on T cells in vitro. Our data indicate that CML cells create an immuno-tolerant environment associated to MDSCs expansion with immunosuppressive capacity mediated by Arg1. In addition, we demonstrated for the first time also an immunosuppressive activity of CML PMNs, suggesting a strong potential immune escape mechanism created by CML cells, which control the anti-tumor reactive T cells. MDSCs should be monitored in imatinib discontinuation trials to understand their importance in relapsing patients.

  11. Subpopulation of human helper and suppressor T lymphocytes

    International Nuclear Information System (INIS)

    Venkataraman, M.; Levin, R.D.; Westerman, M.P.

    1983-01-01

    Mitogen driven differentiation of normal human mononuclear cells is a well-established model for the study of antibody synthesis in man. In certain rare individuals who are clinically normal, unfractionated mononuclear cells or a mixture of purified B plus T lymphocytes differentiate into immunoglobulin producing cells in response to purified protein derivative of tuberculin (PPD) but not in response to pokeweed mitogen (PWM). To evaluate this observation we have irradiated T cells from such individuals to eliminate naturally occurring suppressor T cell activity and then added the irradiated T cells back to autologous B cells before culture. The B cells then responded to PWM. The original PPD responses of cells from these individuals were now significantly reduced. Although, there was no difference between PWM nonresponders and responders in the number of OKT-8 positive cells, elimination of OKT-8 positive cells in the PWM nonresponders with OKT-8 monoclonal antibody and complement resulted in a significantly increased response to PWM. This study indicates that there are suppressor T cells which specifically inhibit B cell response to PWM without affecting the PPD response. These results also show that the helper T cells involved in the PWM response are radioresistant and those involved in the PPD response are radiosensitive

  12. Expansion of myeloid immune suppressor Gr+CD11b+ cells in tumor-bearing host directly promotes tumor angiogenesis | Center for Cancer Research

    Science.gov (United States)

    We demonstrate a novel tumor-promoting role of myeloid immune suppressor Gr+CD11b+ cells, which are evident in cancer patients and tumor-bearing animals. These cells constitute approximately 5% of total cells in tumors. Tumors coinjected with Gr+CD11b+ cells exhibited increased vascular density, vascular maturation, and decreased necrosis. These immune cells produce high

  13. Taxifolin synergizes Andrographolide-induced cell death by attenuation of autophagy and augmentation of caspase dependent and independent cell death in HeLa cells.

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    Mazen Alzaharna

    Full Text Available Andrographolide (Andro has emerged recently as a potential and effective anticancer agent with induction of apoptosis in some cancer cell lines while induction of G2/M arrest with weak apoptosis in others. Few studies have proved that Andro is also effective in combination therapy. The flavonoid Taxifolin (Taxi has showed anti-oxidant and antiproliferative effects against different cancer cells. Therefore, the present study investigated the cytotoxic effects of Andro alone or in combination with Taxi on HeLa cells. The combination of Andro with Taxi was synergistic at all tested concentrations and combination ratios. Andro alone induced caspase-dependent apoptosis which was enhanced by the combination with Taxi and attenuated partly by using Z-Vad-Fmk. Andro induced a protective reactive oxygen species (ROS-dependent autophagy which was attenuated by Taxi. The activation of p53 was involved in Andro-induced autophagy where the use of Taxi or pifithrin-α (PFT-α decreased it while the activation of JNK was involved in the cell death of HeLa cells but not in the induction of autophagy. The mitochondrial outer-membrane permeabilization (MOMP plays an important role in Andro-induced cell death in HeLa cells. Andro alone increased the MOMP which was further increased in the case of combination. This led to the increase in AIF and cytochrome c release from mitochondria which consequently increased caspase-dependent and independent cell death. In conclusion, Andro induced a protective autophagy in HeLa cells which was reduced by Taxi and the cell death was increased by increasing the MOMP and subsequently the caspase-dependent and independent cell death.

  14. Taxifolin synergizes Andrographolide-induced cell death by attenuation of autophagy and augmentation of caspase dependent and independent cell death in HeLa cells

    Science.gov (United States)

    Alzaharna, Mazen; Alqouqa, Iyad; Cheung, Hon-Yeung

    2017-01-01

    Andrographolide (Andro) has emerged recently as a potential and effective anticancer agent with induction of apoptosis in some cancer cell lines while induction of G2/M arrest with weak apoptosis in others. Few studies have proved that Andro is also effective in combination therapy. The flavonoid Taxifolin (Taxi) has showed anti-oxidant and antiproliferative effects against different cancer cells. Therefore, the present study investigated the cytotoxic effects of Andro alone or in combination with Taxi on HeLa cells. The combination of Andro with Taxi was synergistic at all tested concentrations and combination ratios. Andro alone induced caspase-dependent apoptosis which was enhanced by the combination with Taxi and attenuated partly by using Z-Vad-Fmk. Andro induced a protective reactive oxygen species (ROS)-dependent autophagy which was attenuated by Taxi. The activation of p53 was involved in Andro-induced autophagy where the use of Taxi or pifithrin-α (PFT-α) decreased it while the activation of JNK was involved in the cell death of HeLa cells but not in the induction of autophagy. The mitochondrial outer-membrane permeabilization (MOMP) plays an important role in Andro-induced cell death in HeLa cells. Andro alone increased the MOMP which was further increased in the case of combination. This led to the increase in AIF and cytochrome c release from mitochondria which consequently increased caspase-dependent and independent cell death. In conclusion, Andro induced a protective autophagy in HeLa cells which was reduced by Taxi and the cell death was increased by increasing the MOMP and subsequently the caspase-dependent and independent cell death. PMID:28182713

  15. Sorafenib-induced defective autophagy promotes cell death by necroptosis.

    Science.gov (United States)

    Kharaziha, Pedram; Chioureas, Dimitris; Baltatzis, George; Fonseca, Pedro; Rodriguez, Patricia; Gogvadze, Vladimir; Lennartsson, Lena; Björklund, Ann-Charlotte; Zhivotovsky, Boris; Grandér, Dan; Egevad, Lars; Nilsson, Sten; Panaretakis, Theocharis

    2015-11-10

    Autophagy is one of the main cytoprotective mechanisms that cancer cells deploy to withstand the cytotoxic stress and survive the lethal damage induced by anti-cancer drugs. However, under specific conditions, autophagy may, directly or indirectly, induce cell death. In our study, treatment of the Atg5-deficient DU145 prostate cancer cells, with the multi-tyrosine kinase inhibitor, sorafenib, induces mitochondrial damage, autophagy and cell death. Molecular inhibition of autophagy by silencing ULK1 and Beclin1 rescues DU145 cells from cell death indicating that, in this setting, autophagy promotes cell death. Re-expression of Atg5 restores the lipidation of LC3 and rescues DU145 and MEF atg5-/- cells from sorafenib-induced cell death. Despite the lack of Atg5 expression and LC3 lipidation, DU145 cells form autophagosomes as demonstrated by transmission and immuno-electron microscopy, and the formation of LC3 positive foci. However, the lack of cellular content in the autophagosomes, the accumulation of long-lived proteins, the presence of GFP-RFP-LC3 positive foci and the accumulated p62 protein levels indicate that these autophagosomes may not be fully functional. DU145 cells treated with sorafenib undergo a caspase-independent cell death that is inhibited by the RIPK1 inhibitor, necrostatin-1. Furthermore, treatment with sorafenib induces the interaction of RIPK1 with p62, as demonstrated by immunoprecipitation and a proximity ligation assay. Silencing of p62 decreases the RIPK1 protein levels and renders necrostatin-1 ineffective in blocking sorafenib-induced cell death. In summary, the formation of Atg5-deficient autophagosomes in response to sorafenib promotes the interaction of p62 with RIPK leading to cell death by necroptosis.

  16. Plant programmed cell death, ethylene and flower senescence

    NARCIS (Netherlands)

    Woltering, E.J.; Jong, de A.; Hoeberichts, F.A.; Iakimova, E.T.; Kapchina, V.

    2005-01-01

    Programmed cell death (PCD) applies to cell death that is part of the normal life of multicellular organisms. PCD is found throughout the animal and plant kingdoms; it is an active process in which a cell suicide pathway is activated resulting in controlled disassembly of the cell. Most cases of PCD

  17. Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial) Endosymbiont

    Science.gov (United States)

    Zheng, Weiwen; Rasmussen, Ulla; Zheng, Siping; Bao, Xiaodong; Chen, Bin; Gao, Yuan; Guan, Xiong; Larsson, John; Bergman, Birgitta

    2013-01-01

    Programmed cell death (PCD) is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20%) of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays), together with visualization of cytoskeleton alterations (FITC-phalloidin staining), showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20) further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom. PMID:23822984

  18. Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial Endosymbiont.

    Directory of Open Access Journals (Sweden)

    Weiwen Zheng

    Full Text Available Programmed cell death (PCD is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20% of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays, together with visualization of cytoskeleton alterations (FITC-phalloidin staining, showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20 further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom.

  19. Mycobacterium tuberculosis infection induces non-apoptotic cell death of human dendritic cells

    LENUS (Irish Health Repository)

    Ryan, Ruth CM

    2011-10-24

    Abstract Background Dendritic cells (DCs) connect innate and adaptive immunity, and are necessary for an efficient CD4+ and CD8+ T cell response after infection with Mycobacterium tuberculosis (Mtb). We previously described the macrophage cell death response to Mtb infection. To investigate the effect of Mtb infection on human DC viability, we infected these phagocytes with different strains of Mtb and assessed viability, as well as DNA fragmentation and caspase activity. In parallel studies, we assessed the impact of infection on DC maturation, cytokine production and bacillary survival. Results Infection of DCs with live Mtb (H37Ra or H37Rv) led to cell death. This cell death proceeded in a caspase-independent manner, and without nuclear fragmentation. In fact, substrate assays demonstrated that Mtb H37Ra-induced cell death progressed without the activation of the executioner caspases, 3\\/7. Although the death pathway was triggered after infection, the DCs successfully underwent maturation and produced a host-protective cytokine profile. Finally, dying infected DCs were permissive for Mtb H37Ra growth. Conclusions Human DCs undergo cell death after infection with live Mtb, in a manner that does not involve executioner caspases, and results in no mycobactericidal effect. Nonetheless, the DC maturation and cytokine profile observed suggests that the infected cells can still contribute to TB immunity.

  20. Early cell death detection with digital holographic microscopy.

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    Nicolas Pavillon

    Full Text Available BACKGROUND: Digital holography provides a non-invasive measurement of the quantitative phase shifts induced by cells in culture, which can be related to cell volume changes. It has been shown previously that regulation of cell volume, in particular as it relates to ionic homeostasis, is crucially involved in the activation/inactivation of the cell death processes. We thus present here an application of digital holographic microscopy (DHM dedicated to early and label-free detection of cell death. METHODS AND FINDINGS: We provide quantitative measurements of phase signal obtained on mouse cortical neurons, and caused by early neuronal cell volume regulation triggered by excitotoxic concentrations of L-glutamate. We show that the efficiency of this early regulation of cell volume detected by DHM, is correlated with the occurrence of subsequent neuronal death assessed with the widely accepted trypan blue method for detection of cell viability. CONCLUSIONS: The determination of the phase signal by DHM provides a simple and rapid optical method for the early detection of cell death.

  1. Ayanin diacetate-induced cell death is amplified by TRAIL in human leukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Marrero, Maria Teresa; Estevez, Sara; Negrin, Gledy; Quintana, Jose [Departamento de Bioquimica, Unidad Asociada al Consejo Superior de Investigaciones Cientificas, Universidad de Las Palmas de Gran Canaria, Plaza Dr. Pasteur s/n, 35016 Las Palmas de Gran Canaria (Spain); Lopez, Mariana; Perez, Francisco J.; Triana, Jorge [Departamento de Quimica, Universidad de Las Palmas de Gran Canaria, Instituto Canario de Investigacion del Cancer, 35017 Las Palmas de Gran Canaria (Spain); Leon, Francisco [Instituto de Productos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Avda. Astrofisico F. Sanchez 3, 38206 La Laguna, Tenerife (Spain); Estevez, Francisco, E-mail: festevez@dbbf.ulpgc.es [Departamento de Bioquimica, Unidad Asociada al Consejo Superior de Investigaciones Cientificas, Universidad de Las Palmas de Gran Canaria, Plaza Dr. Pasteur s/n, 35016 Las Palmas de Gran Canaria (Spain)

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer Ayanin diacetate as apoptotic inducer in leukemia cells. Black-Right-Pointing-Pointer Cell death was prevented by caspase inhibitors and by the overexpression of Bcl-x{sub L}. Black-Right-Pointing-Pointer The intrinsic and the extrinsic pathways are involved in the mechanism of action. Black-Right-Pointing-Pointer Death receptors are up-regulated and TRAIL enhances apoptotic cell death. -- Abstract: Here we demonstrate that the semi-synthetic flavonoid ayanin diacetate induces cell death selectively in leukemia cells without affecting the proliferation of normal lymphocytes. Incubation of human leukemia cells with ayanin diacetate induced G{sub 2}-M phase cell cycle arrest and apoptosis which was prevented by the non-specific caspase inhibitor z-VAD-fmk and reduced by the overexpression of Bcl-x{sub L}. Ayanin diacetate-induced cell death was found to be associated with: (i) loss of inner mitochondrial membrane potential, (ii) the release of cytochrome c, (iii) the activation of multiple caspases, (iv) cleavage of poly(ADP-ribose) polymerase and (v) the up-regulation of death receptors for TRAIL, DR4 and DR5. Moreover, the combined treatment with ayanin diacetate and TRAIL amplified cell death, compared to single treatments. These results provide a basis for further exploring the potential applications of this combination for the treatment of cancer.

  2. Signal transduction events in aluminum-induced cell death in tomato suspension cells

    NARCIS (Netherlands)

    Iakimova, E.T.; Kapchina-Toteva, V.M.; Woltering, E.J.

    2007-01-01

    In this study, some of the signal transduction events involved in AlCl3-induced cell death in tomato (Lycopersicon esculentum Mill.) suspension cells were elucidated. Cells treated with 100 ¿M AlCl3 showed typical features of programmed cell death (PCD) such as nuclear and cytoplasmic condensation.

  3. Characterization of membrane determinant in old T-cells with suppressor activity

    International Nuclear Information System (INIS)

    Hendricks, L.C.; Heidrick, M.L.

    1986-01-01

    T-cell function declines with age. Many T-cell functions are initiated at the cell membrane; therefore, age-related membrane alterations may contribute to loss of function. They have previously reported developing a monoclonal antibody, HH-AGE-T(1), which recognizes a cell with suppressor activity and binds to 15-20% of the T-cells from old BC3F 1 mice, but only to 0-4% of young T-cells. To further characterize the determinant recognized by HH-AGE-T(1), they analyzed immunoprecipitates (IP) of young and old T-cell membranes by 2D-SDS PAGE, followed by Western blotting. Immunodetection of the blots showed that HH-AGE-T(1) bound a heterodimer (66 kD, pI 8.44 and 36 kD, pI 5.82-7.12 subunits) in IP from old mice; but not young mice. Monoclonal anti-Lyt 2 antibody did not bind the determinant. When IP of iodinated T-cells were run on SDS-PAGE gels followed by blotting and autoradiography of the blots, very prominent bands were detected in the old sample and faint bands were detected in the young sample. These results suggest that HH-AGE-T(1) recognizes a membrane protein which is present in small amounts on young T-cells but which increases markedly with age. Further studies are needed to determine the significance of this age-related membrane change

  4. Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae-Hee, E-mail: leedneo@gmail.com [Departments of Surgery and Pharmacology and Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA (United States); Kim, Dong-Wook [Department of Microbiology, Immunology, and Cancer Biology, University of VA (United States); Jung, Chang-Hwa [Division of Metabolism and Functionality Research, Korea Food Research Institute (Korea, Republic of); Lee, Yong J. [Departments of Surgery and Pharmacology and Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA (United States); Park, Daeho, E-mail: daehopark@gist.ac.kr [School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-09-15

    Glioblastoma multiforme (GBM) is the most lethal and aggressive astrocytoma of primary brain tumors in adults. Although there are many clinical trials to induce the cell death of glioblastoma cells, most glioblastoma cells have been reported to be resistant to TRAIL-induced apoptosis. Here, we showed that gingerol as a major component of ginger can induce TRAIL-mediated apoptosis of glioblastoma. Gingerol increased death receptor (DR) 5 levels in a p53-dependent manner. Furthermore, gingerol decreased the expression level of anti-apoptotic proteins (survivin, c-FLIP, Bcl-2, and XIAP) and increased pro-apoptotic protein, Bax and truncate Bid, by generating reactive oxygen species (ROS). We also found that the sensitizing effects of gingerol in TRAIL-induced cell death were blocked by scavenging ROS or overexpressing anti-apoptotic protein (Bcl-2). Therefore, we showed the functions of gingerol as a sensitizing agent to induce cell death of TRAIL-resistant glioblastoma cells. This study gives rise to the possibility of applying gingerol as an anti-tumor agent that can be used for the purpose of combination treatment with TRAIL in TRAIL-resistant glioblastoma tumor therapy. - Highlights: • Most GBM cells have been reported to be resistant to TRAIL-induced apoptosis. • Gingerol enhances the expression level of anti-apoptotic proteins by ROS. • Gingerol enhances TRAIL-induced apoptosis through actions on the ROS–Bcl2 pathway.

  5. Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

    International Nuclear Information System (INIS)

    Lee, Dae-Hee; Kim, Dong-Wook; Jung, Chang-Hwa; Lee, Yong J.; Park, Daeho

    2014-01-01

    Glioblastoma multiforme (GBM) is the most lethal and aggressive astrocytoma of primary brain tumors in adults. Although there are many clinical trials to induce the cell death of glioblastoma cells, most glioblastoma cells have been reported to be resistant to TRAIL-induced apoptosis. Here, we showed that gingerol as a major component of ginger can induce TRAIL-mediated apoptosis of glioblastoma. Gingerol increased death receptor (DR) 5 levels in a p53-dependent manner. Furthermore, gingerol decreased the expression level of anti-apoptotic proteins (survivin, c-FLIP, Bcl-2, and XIAP) and increased pro-apoptotic protein, Bax and truncate Bid, by generating reactive oxygen species (ROS). We also found that the sensitizing effects of gingerol in TRAIL-induced cell death were blocked by scavenging ROS or overexpressing anti-apoptotic protein (Bcl-2). Therefore, we showed the functions of gingerol as a sensitizing agent to induce cell death of TRAIL-resistant glioblastoma cells. This study gives rise to the possibility of applying gingerol as an anti-tumor agent that can be used for the purpose of combination treatment with TRAIL in TRAIL-resistant glioblastoma tumor therapy. - Highlights: • Most GBM cells have been reported to be resistant to TRAIL-induced apoptosis. • Gingerol enhances the expression level of anti-apoptotic proteins by ROS. • Gingerol enhances TRAIL-induced apoptosis through actions on the ROS–Bcl2 pathway

  6. Identification of a genetic interaction between the tumor suppressor EAF2 and the retinoblastoma protein (Rb) signaling pathway in C. elegans and prostate cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Liquan; Wang, Dan [Department of Urology, The University of Pittsburgh, 5200 Centre Avenue, Pittsburgh, PA 15216 (United States); Fisher, Alfred L., E-mail: fishera2@uthscsa.edu [Division of Geriatrics, Gerontology, and Palliative Medicine, Department of Medicine, UTHSCSA, San Antonio, TX 78229 (United States); Center for Healthy Aging, UTHSCSA, San Antonio, TX 78229 (United States); GRECC, STVAHCS, San Antonio, TX 78229 (United States); Wang, Zhou, E-mail: wangz2@upmc.edu [Department of Urology, The University of Pittsburgh, 5200 Centre Avenue, Pittsburgh, PA 15216 (United States); GRECC, STVAHCS, San Antonio, TX 78229 (United States)

    2014-05-02

    Highlights: • RNAi screen identified genetic enhancers for the C. elegans homolog of EAF2. • EAF2 and RBBP4 proteins physically bind to each other and alter transcription. • Overexpression of EAF2 and RBBP4 induces the cell death in prostate cancer cells. - Abstract: The tumor suppressor EAF2 is regulated by androgen signaling and associated with prostate cancer. While EAF2 and its partner ELL have been shown to be members of protein complexes involved in RNA polymerase II transcriptional elongation, the biologic roles for EAF2 especially with regards to the development of cancer remains poorly understood. We have previously identified the eaf-1 gene in Caenorhabditiselegans as the ortholog of EAF2, and shown that eaf-1 interacts with the ELL ortholog ell-1 to control development and fertility in worms. To identify genetic pathways that interact with eaf-1, we screened RNAi libraries consisting of transcription factors, phosphatases, and chromatin-modifying factors to identify genes which enhance the effects of eaf-1(tm3976) on fertility. From this screen, we identified lin-53, hmg-1.2, pha-4, ruvb-2 and set-6 as hits. LIN-53 is the C. elegans ortholog of human retinoblastoma binding protein 4/7 (RBBP 4/7), which binds to the retinoblastoma protein and inhibits the Ras signaling pathway. We find that lin-53 showed a synthetic interaction with eaf-1(tm3976) where knockdown of lin-53 in an eaf-1(tm3976) mutant resulted in sterile worms. This phenotype may be due to cell death as the treated worms contain degenerated embryos with increased expression of the ced-1:GFP cell death marker. Further we find that the interaction between eaf-1 and lin-53/RBBP4/7 also exists in vertebrates, which is reflected by the formation of a protein complex between EAF2 and RBBP4/7. Finally, overexpression of either human EAF2 or RBBP4 in LNCaP cells induced the cell death while knockdown of EAF2 in LNCaP enhanced cell proliferation, indicating an important role of EAF2 in

  7. Epidermal cell death in frogs with chytridiomycosis

    Directory of Open Access Journals (Sweden)

    Laura A. Brannelly

    2017-02-01

    Full Text Available Background Amphibians are declining at an alarming rate, and one of the major causes of decline is the infectious disease chytridiomycosis. Parasitic fungal sporangia occur within epidermal cells causing epidermal disruption, but these changes have not been well characterised. Apoptosis (planned cell death can be a damaging response to the host but may alternatively be a mechanism of pathogen removal for some intracellular infections. Methods In this study we experimentally infected two endangered amphibian species Pseudophryne corroboree and Litoria verreauxii alpina with the causal agent of chytridiomycosis. We quantified cell death in the epidermis through two assays: terminal transferase-mediated dUTP nick end-labelling (TUNEL and caspase 3/7. Results Cell death was positively associated with infection load and morbidity of clinically infected animals. In infected amphibians, TUNEL positive cells were concentrated in epidermal layers, correlating to the localisation of infection within the skin. Caspase activity was stable and low in early infection, where pathogen loads were light but increasing. In animals that recovered from infection, caspase activity gradually returned to normal as the infection cleared. Whereas, in amphibians that did not recover, caspase activity increased dramatically when infection loads peaked. Discussion Increased cell death may be a pathology of the fungal parasite, likely contributing to loss of skin homeostatic functions, but it is also possible that apoptosis suppression may be used initially by the pathogen to help establish infection. Further research should explore the specific mechanisms of cell death and more specifically apoptosis regulation during fungal infection.

  8. The Drosophila Netrin receptor frazzled/DCC functions as an invasive tumor suppressor

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    Duman-Scheel Molly

    2011-06-01

    Full Text Available Abstract Background Loss of heterozygosity at 18q, which includes the Deleted in Colorectal Cancer (DCC gene, has been linked to many human cancers. However, it is unclear if loss of DCC is the specific underlying cause of these cancers. The Drosophila imaginal discs are excellent systems in which to study DCC function, as it is possible to model human tumors through the generation of somatic clones of cells bearing multiple genetic lesions. Here, these attributes of the fly system were utilized to investigate the potential tumor suppressing functions of the Drosophila DCC homologue frazzled (fra during eye-antennal disc development. Results Most fra loss of function clones are eliminated during development. However, when mutant clone cells generated in the developing eye were rescued from death, partially differentiated eye cells were found outside of the normal eye field, and in extreme cases distant sites of the body. Characterization of these cells during development indicates that fra mutant cells display characteristics of invasive tumor cells, including increased levels of phospho-ERK, phospho-JNK, and Mmp-1, changes in cadherin expression, remodeling of the actin cytoskeleton, and loss of polarity. Mutation of fra promotes basement membrane degradation and invasion which are repressed by inhibition of Rho1 signaling. Although inhibition of JNK signaling blocks invasive phenotypes in some metastatic cancer models in flies, blocking JNK signaling inhibits fra mutant cell death, thereby enhancing the fra mutant phenotype. Conclusions The results of this investigation provide the first direct link between point mutations in fra/DCC and metastatic phenotypes in an animal model and suggest that Fra functions as an invasive tumor suppressor during Drosophila development.

  9. Crystalline structure of pulverized dental calculus induces cell death in oral epithelial cells.

    Science.gov (United States)

    Ziauddin, S M; Yoshimura, A; Montenegro Raudales, J L; Ozaki, Y; Higuchi, K; Ukai, T; Kaneko, T; Miyazaki, T; Latz, E; Hara, Y

    2018-06-01

    Dental calculus is a mineralized deposit attached to the tooth surface. We have shown that cellular uptake of dental calculus triggers nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation, leading to the processing of the interleukin-1β precursor into its mature form in mouse and human phagocytes. The activation of the NLRP3 inflammasome also induced a lytic form of programmed cell death, pyroptosis, in these cells. However, the effects of dental calculus on other cell types in periodontal tissue have not been investigated. The aim of this study was to determine whether dental calculus can induce cell death in oral epithelial cells. HSC-2 human oral squamous carcinoma cells, HOMK107 human primary oral epithelial cells and immortalized mouse macrophages were exposed to dental calculus or 1 of its components, hydroxyapatite crystals. For inhibition assays, the cells were exposed to dental calculus in the presence or absence of cytochalasin D (endocytosis inhibitor), z-YVAD-fmk (caspase-1 inhibitor) or glyburide (NLRP3 inflammasome inhibitor). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) release and staining with propidium iodide. Tumor necrosis factor-α production was quantified by enzyme-linked immunosorbent assay. Oral epithelial barrier function was examined by permeability assay. Dental calculus induced cell death in HSC-2 cells, as judged by LDH release and propidium iodide staining. Dental calculus also induced LDH release from HOMK107 cells. Following heat treatment, dental calculus lost its capacity to induce tumor necrosis factor-α in mouse macrophages, but could induce LDH release in HSC-2 cells, indicating a major role of inorganic components in cell death. Hydroxyapatite crystals also induced cell death in both HSC-2 and HOMK107 cells, as judged by LDH release, indicating the capacity of crystal particles to induce cell death. Cell death induced by dental

  10. History of myeloid derived suppressor cells (MDSCs) in the macro- and micro-environment of tumour-bearing hosts

    Science.gov (United States)

    Talmadge, James E.; Gabrilovich, Dmitry I.

    2015-01-01

    Tumour-induced granulocytic hyperplasia is associated with tumour vasculogenesis and escape from immunity via T-cell suppression. Initially, these myeloid cells were identified as granulocytes or monocytes; however, recent studies revealed that this hyperplasia was associated with populations of multi-potent progenitor cells identified as myeloid-derived suppressor cells (MDSCs). The discovery and study of MDSCs have provided a wealth of information regarding tumour pathobiology, extended our understanding of neoplastic progression, and modified our approaches to immune adjuvant therapy. In this perspective, we discuss the history of MDSCs, their influence on tumour progression and metastasis, and the crosstalk between tumour cells, MDSCs, and the host macroenvironment. PMID:24060865

  11. Immune suppression with supraoptimal doses of antigen in contact sensitivity. I. Demonstration of suppressor cells and their sensitivity to cyclophosphamide.

    Science.gov (United States)

    Sy, M S; Miller, S D; Claman, H N

    1977-07-01

    Immunologic suppression was induced in a mouse model of contact sensitization to DNFB by using supraoptimal doses of antigen. In these studies, in vivo measurement of ear swelling as an indication of immunologic responsiveness correlated well with measurement of in vitro antigen-induced cell proliferation. This unresponsiveness was specific, since supraoptimal doses of DNFB did not interfere with the development of contact sensitivity to another contactant, oxazolone. The decrease in responsiveness is a form of active suppression, as lymphoid cells from supraoptimally sensitized donors transferred suppression to normal recipients. Furthermore, pretreatment with cyclophosphamide (Cy) reversed the suppression seen in supraoptimally sensitized animals but had no effect on the optimal sensitization regimen. These results indicate that supraoptimal doses of contactants can activate suppressor cells and that precursors of these cells are sensitive to Cy. Such suppressors regenerate within 7 to 14 days after Cy treatment. The ability of Cy pretreatment to affect supraoptimal sensitization without affecting optimal sensitization confirms other reports indicating that the observed results of Cy treatment depend critically upon the dose of antigen used.

  12. Increasing RpoS expression causes cell death in Borrelia burgdorferi.

    Directory of Open Access Journals (Sweden)

    Linxu Chen

    Full Text Available RpoS, one of the two alternative σ factors in Borrelia burgdorferi, is tightly controlled by multiple regulators and, in turn, determines expression of many critical virulence factors. Here we show that increasing RpoS expression causes cell death. The immediate effect of increasing RpoS expression was to promote bacterial division and as a consequence result in a rapid increase in cell number before causing bacterial death. No DNA fragmentation or degradation was observed during this induced cell death. Cryo-electron microscopy showed induced cells first formed blebs, which were eventually released from dying cells. Apparently blebbing initiated cell disintegration leading to cell death. These findings led us to hypothesize that increasing RpoS expression triggers intracellular programs and/or pathways that cause spirochete death. The potential biological significance of induced cell death may help B. burgdorferi regulate its population to maintain its life cycle in nature.

  13. The p75NTR tumor suppressor induces cell cycle arrest facilitating caspase mediated apoptosis in prostate tumor cells

    International Nuclear Information System (INIS)

    Khwaja, Fatima; Tabassum, Arshia; Allen, Jeff; Djakiew, Daniel

    2006-01-01

    The p75 neurotrophin receptor (p75 NTR ) is a death receptor which belongs to the tumor necrosis factor receptor super-family of membrane proteins. This study shows that p75 NTR retarded cell cycle progression by induced accumulation of cells in G0/G1 and a reduction in the S phase of the cell cycle. The rescue of tumor cells from cell cycle progression by a death domain deleted (ΔDD) dominant-negative antagonist of p75 NTR showed that the death domain transduced anti-proliferative activity in a ligand-independent manner. Conversely, addition of NGF ligand rescued retardation of cell cycle progression with commensurate changes in components of the cyclin/cdk holoenzyme complex. In the absence of ligand, p75 NTR -dependent cell cycle arrest facilitated an increase in apoptotic nuclear fragmentation of the prostate cancer cells. Apoptosis of p75 NTR expressing cells occurred via the intrinsic mitochondrial pathway leading to a sequential caspase-9 and -7 cascade. Since the death domain deleted dominant-negative antagonist of p75 NTR rescued intrinsic caspase associated apoptosis in PC-3 cells, this shows p75 NTR was integral to ligand independent induction of apoptosis. Moreover, the ability of ligand to ameliorate the p75 NTR -dependent intrinsic apoptotic cascade indicates that NGF functioned as a survival factor for p75 NTR expressing prostate cancer cells

  14. Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres

    International Nuclear Information System (INIS)

    Ji, Qing; Hao, Xinbao; Meng, Yang; Zhang, Min; DeSano, Jeffrey; Fan, Daiming; Xu, Liang

    2008-01-01

    MicroRNAs (miRNAs), some of which function as oncogenes or tumor suppressor genes, are involved in carcinogenesis via regulating cell proliferation and/or cell death. MicroRNA miR-34 was recently found to be a direct target of p53, functioning downstream of the p53 pathway as a tumor suppressor. miR-34 targets Notch, HMGA2, and Bcl-2, genes involved in the self-renewal and survival of cancer stem cells. The role of miR-34 in gastric cancer has not been reported previously. In this study, we examined the effects of miR-34 restoration on p53-mutant human gastric cancer cells and potential target gene expression. Human gastric cancer cells were transfected with miR-34 mimics or infected with the lentiviral miR-34-MIF expression system, and validated by miR-34 reporter assay using Bcl-2 3'UTR reporter. Potential target gene expression was assessed by Western blot for proteins, and by quantitative real-time RT-PCR for mRNAs. The effects of miR-34 restoration were assessed by cell growth assay, cell cycle analysis, caspase-3 activation, and cytotoxicity assay, as well as by tumorsphere formation and growth. Human gastric cancer Kato III cells with miR-34 restoration reduced the expression of target genes Bcl-2, Notch, and HMGA2. Bcl-2 3'UTR reporter assay showed that the transfected miR-34s were functional and confirmed that Bcl-2 is a direct target of miR-34. Restoration of miR-34 chemosensitized Kato III cells with a high level of Bcl-2, but not MKN-45 cells with a low level of Bcl-2. miR-34 impaired cell growth, accumulated the cells in G1 phase, increased caspase-3 activation, and, more significantly, inhibited tumorsphere formation and growth. Our results demonstrate that in p53-deficient human gastric cancer cells, restoration of functional miR-34 inhibits cell growth and induces chemosensitization and apoptosis, indicating that miR-34 may restore p53 function. Restoration of miR-34 inhibits tumorsphere formation and growth, which is reported to be

  15. Dissecting functions of the retinoblastoma tumor suppressor and the related pocket proteins by integrating genetic, cell biology, and electrophoretic techniques

    DEFF Research Database (Denmark)

    Hansen, Klaus; Lukas, J; Holm, K

    1999-01-01

    The members of the 'pocket protein' family, comprising the retinoblastoma tumor suppressor (pRB) and its relatives, p107 and p130, negatively regulate cell proliferation and modulate fundamental biological processes including embryonic development, differentiation, homeostatic tissue renewal...

  16. The Role and Potential Therapeutic Application of Myeloid-Derived Suppressor Cells in Allo- and Autoimmunity

    Directory of Open Access Journals (Sweden)

    Qi Zhang

    2015-01-01

    Full Text Available Myeloid-derived suppressor cells (MDSCs are a heterogeneous population of cells that consists of myeloid progenitor cells and immature myeloid cells. They have been identified as a cell population that may affect the activation of CD4+ and CD8+ T-cells to regulate the immune response negatively, which makes them attractive targets for the treatment of transplantation and autoimmune diseases. Several studies have suggested the potential suppressive effect of MDSCs on allo- and autoimmune responses. Conversely, MDSCs have also been found at various stages of differentiation, accumulating during pathological situations, not only during tumor development but also in a variety of inflammatory immune responses, bone marrow transplantation, and some autoimmune diseases. These findings appear to be contradictory. In this review, we summarize the roles of MDSCs in different transplantation and autoimmune diseases models as well as the potential to target these cells for therapeutic benefit.

  17. In vivo evidence for CD4+ and CD8+ suppressor T cells in vaccination-induced suppression of murine experimental autoimmune thyroiditis

    International Nuclear Information System (INIS)

    Flynn, J.C.; Kong, Y.C.

    1991-01-01

    In several experimental autoimmune diseases, including experimental autoimmune thyroiditis (EAT), vaccination with attenuated autoantigen-specific T cells has provided protection against subsequent induction of disease. However, the mechanism(s) of vaccination-induced suppression remains to be clarified. Since the authors have previously shown that suppression generated by pretreatment with mouse thyroglobulin (MTg) or thyroid-stimulating hormone in EAT is mediated by CD4+, not CD8+, suppressor T cells, they examined the role of T cell subsets in vaccination-induced suppression of EAT. Mice were vaccinated with irradiated, MTg-primed, and MTg-activated spleen cells and then challenged. Pretreatment with these cells suppressed EAT induced by immunization with MTg and adjuvant, but not by adoptive transfer of thyroiditogenic cells, suggesting a mechanism of afferent suppression. The activation of suppressor mechanisms did not require CD8+ cells, since mice depleted of CD8+ cells before vaccination showed reduced EAT comparable to control vaccinated mice. Furthermore, depletion of either the CD4+ or the CD8+ subset after vaccination did not significantly abrogate suppression. However, suppression was eliminated by the depletion of both CD4+ and CD8+ cells in vaccinated mice. These results provide evidence for the cooperative effects of CD4+ and CD8+ T cells in vaccination-induced suppression of EAT

  18. Triglyceride-induced macrophage cell death is triggered by caspase-1.

    Science.gov (United States)

    Son, Sin Jee; Rhee, Ki-Jong; Lim, Jaewon; Kim, Tae Ue; Kim, Tack-Joong; Kim, Yoon Suk

    2013-01-01

    Triglyceride (TG) induces macrophage cell death which contributes to the development of atherosclerosis. We confirmed that exogenous TG accumulates in human THP-1 macrophages and causes cell death. TG treated THP-1 macrophages exhibited no change in tumor necrosis factor (TNF)-α, interleukin (IL)-18, macrophage inflammatory protein (MIP)-1α, and IL-1R1 receptor mRNA expression. However, there was a marked decrease in IL-1β mRNA expression but an increase in IL-1β protein secretion. Decreased expression of IL-1β mRNA and increased secretion of IL-1β protein was not the direct cause of cell death. Until now, TG was assumed to induce necrotic cell death in macrophages. Since caspase-1 is known to be involved in activation and secretion of IL-1β protein and pyroptotic cell death, next we determined whether caspase-1 is associated with TG-induced macrophage cell death. We found an increase in caspase-1 activity in TG-treated THP-1 macrophages and inhibition of caspase-1 activity using a specific inhibitor partially rescued cell death. These results suggest activation of the pyroptotic pathway by TG. This is the first report implicating the activation of caspase-1 and the triggering of the pyroptosis pathway in TG-induced macrophage cell death.

  19. Comprehensive identification of genes driven by ERV9-LTRs reveals TNFRSF10B as a re-activatable mediator of testicular cancer cell death

    Science.gov (United States)

    Beyer, U; Krönung, S K; Leha, A; Walter, L; Dobbelstein, M

    2016-01-01

    The long terminal repeat (LTR) of human endogenous retrovirus type 9 (ERV9) acts as a germline-specific promoter that induces the expression of a proapoptotic isoform of the tumor suppressor homologue p63, GTAp63, in male germline cells. Testicular cancer cells silence this promoter, but inhibitors of histone deacetylases (HDACs) restore GTAp63 expression and give rise to apoptosis. We show here that numerous additional transcripts throughout the genome are driven by related ERV9-LTRs. 3' Rapid amplification of cDNA ends (3'RACE) was combined with next-generation sequencing to establish a large set of such mRNAs. HDAC inhibitors induce these ERV9-LTR-driven genes but not the LTRs from other ERVs. In particular, a transcript encoding the death receptor DR5 originates from an ERV9-LTR inserted upstream of the protein coding regions of the TNFRSF10B gene, and it shows an expression pattern similar to GTAp63. When treating testicular cancer cells with HDAC inhibitors as well as the death ligand TNF-related apoptosis-inducing ligand (TRAIL), rapid cell death was observed, which depended on TNFRSF10B expression. HDAC inhibitors also cooperate with cisplatin (cDDP) to promote apoptosis in testicular cancer cells. ERV9-LTRs not only drive a large set of human transcripts, but a subset of them acts in a proapoptotic manner. We propose that this avoids the survival of damaged germ cells. HDAC inhibition represents a strategy of restoring the expression of a class of ERV9-LTR-mediated genes in testicular cancer cells, thereby re-enabling tumor suppression. PMID:26024393

  20. Mechanical Stress Promotes Cisplatin-Induced Hepatocellular Carcinoma Cell Death

    Science.gov (United States)

    Riad, Sandra; Bougherara, Habiba

    2015-01-01

    Cisplatin (CisPt) is a commonly used platinum-based chemotherapeutic agent. Its efficacy is limited due to drug resistance and multiple side effects, thereby warranting a new approach to improving the pharmacological effect of CisPt. A newly developed mathematical hypothesis suggested that mechanical loading, when coupled with a chemotherapeutic drug such as CisPt and immune cells, would boost tumor cell death. The current study investigated the aforementioned mathematical hypothesis by exposing human hepatocellular liver carcinoma (HepG2) cells to CisPt, peripheral blood mononuclear cells, and mechanical stress individually and in combination. HepG2 cells were also treated with a mixture of CisPt and carnosine with and without mechanical stress to examine one possible mechanism employed by mechanical stress to enhance CisPt effects. Carnosine is a dipeptide that reportedly sequesters platinum-based drugs away from their pharmacological target-site. Mechanical stress was achieved using an orbital shaker that produced 300 rpm with a horizontal circular motion. Our results demonstrated that mechanical stress promoted CisPt-induced death of HepG2 cells (~35% more cell death). Moreover, results showed that CisPt-induced death was compromised when CisPt was left to mix with carnosine 24 hours preceding treatment. Mechanical stress, however, ameliorated cell death (20% more cell death). PMID:25685789

  1. Mechanical Stress Promotes Cisplatin-Induced Hepatocellular Carcinoma Cell Death

    Directory of Open Access Journals (Sweden)

    Laila Ziko

    2015-01-01

    Full Text Available Cisplatin (CisPt is a commonly used platinum-based chemotherapeutic agent. Its efficacy is limited due to drug resistance and multiple side effects, thereby warranting a new approach to improving the pharmacological effect of CisPt. A newly developed mathematical hypothesis suggested that mechanical loading, when coupled with a chemotherapeutic drug such as CisPt and immune cells, would boost tumor cell death. The current study investigated the aforementioned mathematical hypothesis by exposing human hepatocellular liver carcinoma (HepG2 cells to CisPt, peripheral blood mononuclear cells, and mechanical stress individually and in combination. HepG2 cells were also treated with a mixture of CisPt and carnosine with and without mechanical stress to examine one possible mechanism employed by mechanical stress to enhance CisPt effects. Carnosine is a dipeptide that reportedly sequesters platinum-based drugs away from their pharmacological target-site. Mechanical stress was achieved using an orbital shaker that produced 300 rpm with a horizontal circular motion. Our results demonstrated that mechanical stress promoted CisPt-induced death of HepG2 cells (~35% more cell death. Moreover, results showed that CisPt-induced death was compromised when CisPt was left to mix with carnosine 24 hours preceding treatment. Mechanical stress, however, ameliorated cell death (20% more cell death.

  2. The convergence of radiation and immunogenic cell death signaling pathways

    International Nuclear Information System (INIS)

    Golden, Encouse B.; Pellicciotta, Ilenia; Demaria, Sandra; Barcellos-Hoff, Mary H.; Formenti, Silvia C.

    2012-01-01

    Ionizing radiation (IR) triggers programmed cell death in tumor cells through a variety of highly regulated processes. Radiation-induced tumor cell death has been studied extensively in vitro and is widely attributed to multiple distinct mechanisms, including apoptosis, necrosis, mitotic catastrophe (MC), autophagy, and senescence, which may occur concurrently. When considering tumor cell death in the context of an organism, an emerging body of evidence suggests there is a reciprocal relationship in which radiation stimulates the immune system, which in turn contributes to tumor cell kill. As a result, traditional measurements of radiation-induced tumor cell death, in vitro, fail to represent the extent of clinically observed responses, including reductions in loco-regional failure rates and improvements in metastases free and overall survival. Hence, understanding the immunological responses to the type of radiation-induced cell death is critical. In this review, the mechanisms of radiation-induced tumor cell death are described, with particular focus on immunogenic cell death (ICD). Strategies combining radiotherapy with specific chemotherapies or immunotherapies capable of inducing a repertoire of cancer specific immunogens might potentiate tumor control not only by enhancing cell kill but also through the induction of a successful anti-tumor vaccination that improves patient survival.

  3. Tumor suppressor protein SMAR1 modulates the roughness of cell surface: combined AFM and SEM study

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    Mamgain Hitesh

    2009-10-01

    Full Text Available Abstract Background Imaging tools such as scanning electron microscope (SEM and atomic force microscope (AFM can be used to produce high-resolution topographic images of biomedical specimens and hence are well suited for imaging alterations in cell morphology. We have studied the correlation of SMAR1 expression with cell surface smoothness in cell lines as well as in different grades of human breast cancer and mouse tumor sections. Methods We validated knockdown and overexpression of SMAR1 using RT-PCR as well as Western blotting in human embryonic kidney (HEK 293, human breast cancer (MCF-7 and mouse melanoma (B16F1 cell lines. The samples were then processed for cell surface roughness studies using atomic force microscopy (AFM and scanning electron microscopy (SEM. The same samples were used for microarray analysis as well. Tumors sections from control and SMAR1 treated mice as well as tissues sections from different grades of human breast cancer on poly L-lysine coated slides were used for AFM and SEM studies. Results Tumor sections from mice injected with melanoma cells showed pronounced surface roughness. In contrast, tumor sections obtained from nude mice that were first injected with melanoma cells followed by repeated injections of SMAR1-P44 peptide, exhibited relatively smoother surface profile. Interestingly, human breast cancer tissue sections that showed reduced SMAR1 expression exhibited increased surface roughness compared to the adjacent normal breast tissue. Our AFM data establishes that treatment of cells with SMAR1-P44 results into increase in cytoskeletal volume that is supported by comparative gene expression data showing an increase in the expression of specific cytoskeletal proteins compared to the control cells. Altogether, these findings indicate that tumor suppressor function of SMAR1 might be exhibited through smoothening of cell surface by regulating expression of cell surface proteins. Conclusion Tumor suppressor

  4. Cell death triggered by alpha-emitting 213Bi-immunoconjugates in HSC45-M2 gastric cancer cells is different from apoptotic cell death

    International Nuclear Information System (INIS)

    Seidl, Christof; Schroeck, Hedwig; Seidenschwang, Sabine; Beck, Roswitha; Schwaiger, Markus; Senekowitsch-Schmidtke, Reingard; Schmid, Ernst; Abend, Michael; Becker, Karl-Friedrich; Apostolidis, Christos; Nikula, Tuomo K.; Kremmer, Elisabeth

    2005-01-01

    Radioimmunotherapy with α-particle-emitting nuclides, such as 213 Bi, is a promising concept for the elimination of small tumour nodules or single disseminated tumour cells. The aim of this study was to investigate cellular damage and the mode of cell death triggered by 213 Bi-immunoconjugates. Human gastric cancer cells (HSC45-M2) expressing d9-E-cadherin were incubated with different levels of activity of 213 Bi-d9MAb targeting d9-E-cadherin and 213 Bi-d8MAb, which does not bind to d9-E-cadherin. Micronucleated (M) cells, abnormal (A) cells and apoptotic (A) [(MAA)] cells were scored microscopically in the MAA assay following fluorescent staining of nuclei and cytoplasm. Chromosomal aberrations were analysed microscopically following Giemsa staining. The effect of z-VAD-fmk, known to inhibit apoptosis, on the prevention of cell death was investigated following treatment of HSC45-M2 cells with sorbitol as well as 213 Bi-d9MAb. Activation of caspase 3 after incubation of HSC45-M2 cells with both sorbitol and 213 Bi-d9MAb was analysed via Western blotting. Following incubation of HSC45-M2 human gastric cancer cells expressing d9-E-cadherin with 213 Bi-d9MAb the number of cells killed increased proportional to the applied activity concentration. Microscopically visible effects of α-irradiation of HSC45-M2 cells were formation of micronuclei and severe chromosomal aberrations. Preferential induction of these lesions with specific 213 Bi-d9MAb compared with unspecific 213 Bi-d8MAb (not targeting d9-E-cadherin) was not observed if the number of floating, i.e. unbound 213 Bi-immunoconjugates per cell exceeded 2 x 10 4 , most likely due to intense crossfire. In contrast to sorbitol-induced cell death, cell death triggered by 213 Bi-immunoconjugates was independent of caspase 3 activation and could not be inhibited by z-VAD-fmk, known to suppress the apoptotic pathway. 213 Bi-immunoconjugates seem to induce a mode of cell death different from apoptosis in HSC45-M2 cells

  5. Guidelines and recommendations on yeast cell death nomenclature

    Directory of Open Access Journals (Sweden)

    Didac Carmona-Gutierrez

    2018-01-01

    Full Text Available Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research.

  6. Guidelines and recommendations on yeast cell death nomenclature

    Science.gov (United States)

    Carmona-Gutierrez, Didac; Bauer, Maria Anna; Zimmermann, Andreas; Aguilera, Andrés; Austriaco, Nicanor; Ayscough, Kathryn; Balzan, Rena; Bar-Nun, Shoshana; Barrientos, Antonio; Belenky, Peter; Blondel, Marc; Braun, Ralf J.; Breitenbach, Michael; Burhans, William C.; Büttner, Sabrina; Cavalieri, Duccio; Chang, Michael; Cooper, Katrina F.; Côrte-Real, Manuela; Costa, Vítor; Cullin, Christophe; Dawes, Ian; Dengjel, Jörn; Dickman, Martin B.; Eisenberg, Tobias; Fahrenkrog, Birthe; Fasel, Nicolas; Fröhlich, Kai-Uwe; Gargouri, Ali; Giannattasio, Sergio; Goffrini, Paola; Gourlay, Campbell W.; Grant, Chris M.; Greenwood, Michael T.; Guaragnella, Nicoletta; Heger, Thomas; Heinisch, Jürgen; Herker, Eva; Herrmann, Johannes M.; Hofer, Sebastian; Jiménez-Ruiz, Antonio; Jungwirth, Helmut; Kainz, Katharina; Kontoyiannis, Dimitrios P.; Ludovico, Paula; Manon, Stéphen; Martegani, Enzo; Mazzoni, Cristina; Megeney, Lynn A.; Meisinger, Chris; Nielsen, Jens; Nyström, Thomas; Osiewacz, Heinz D.; Outeiro, Tiago F.; Park, Hay-Oak; Pendl, Tobias; Petranovic, Dina; Picot, Stephane; Polčic, Peter; Powers, Ted; Ramsdale, Mark; Rinnerthaler, Mark; Rockenfeller, Patrick; Ruckenstuhl, Christoph; Schaffrath, Raffael; Segovia, Maria; Severin, Fedor F.; Sharon, Amir; Sigrist, Stephan J.; Sommer-Ruck, Cornelia; Sousa, Maria João; Thevelein, Johan M.; Thevissen, Karin; Titorenko, Vladimir; Toledano, Michel B.; Tuite, Mick; Vögtle, F.-Nora; Westermann, Benedikt; Winderickx, Joris; Wissing, Silke; Wölfl, Stefan; Zhang, Zhaojie J.; Zhao, Richard Y.; Zhou, Bing; Galluzzi, Lorenzo; Kroemer, Guido; Madeo, Frank

    2018-01-01

    Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of morphological and biochemical criteria. Specifically, we provide consensus guidelines on the differential definition of terms including apoptosis, regulated necrosis, and autophagic cell death, as we refer to additional cell death routines that are relevant for the biology of (at least some species of) yeast. As this area of investigation advances rapidly, changes and extensions to this set of recommendations will be implemented in the years to come. Nonetheless, we strongly encourage the authors, reviewers and editors of scientific articles to adopt these collective standards in order to establish an accurate framework for yeast cell death research and, ultimately, to accelerate the progress of this vibrant field of research. PMID:29354647

  7. Complementation of non-tumorigenicity of HPV18-positive cervical carcinoma cells involves differential mRNA expression of cellular genes including potential tumor suppressor genes on chromosome 11q13.

    Science.gov (United States)

    Kehrmann, Angela; Truong, Ha; Repenning, Antje; Boger, Regina; Klein-Hitpass, Ludger; Pascheberg, Ulrich; Beckmann, Alf; Opalka, Bertram; Kleine-Lowinski, Kerstin

    2013-01-01

    The fusion between human tumorigenic cells and normal human diploid fibroblasts results in non-tumorigenic hybrid cells, suggesting a dominant role for tumor suppressor genes in the generated hybrid cells. After long-term cultivation in vitro, tumorigenic segregants may arise. The loss of tumor suppressor genes on chromosome 11q13 has been postulated to be involved in the induction of the tumorigenic phenotype of human papillomavirus (HPV)18-positive cervical carcinoma cells and their derived tumorigenic hybrid cells after subcutaneous injection in immunocompromised mice. The aim of this study was the identification of novel cellular genes that may contribute to the suppression of the tumorigenic phenotype of non-tumorigenic hybrid cells in vivo. We used cDNA microarray technology to identify differentially expressed cellular genes in tumorigenic HPV18-positive hybrid and parental HeLa cells compared to non-tumorigenic HPV18-positive hybrid cells. We detected several as yet unknown cellular genes that play a role in cell differentiation, cell cycle progression, cell-cell communication, metastasis formation, angiogenesis, antigen presentation, and immune response. Apart from the known differentially expressed genes on 11q13 (e.g., phosphofurin acidic cluster sorting protein 1 (PACS1) and FOS ligand 1 (FOSL1 or Fra-1)), we detected novel differentially expressed cellular genes located within the tumor suppressor gene region (e.g., EGF-containing fibulin-like extracellular matrix protein 2 (EFEMP2) and leucine rich repeat containing 32 (LRRC32) (also known as glycoprotein-A repetitions predominant (GARP)) that may have potential tumor suppressor functions in this model system of non-tumorigenic and tumorigenic HeLa x fibroblast hybrid cells. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Engineered reversal of drug resistance in cancer cells--metastases suppressor factors as change agents.

    Science.gov (United States)

    Yadav, Vinod Kumar; Kumar, Akinchan; Mann, Anita; Aggarwal, Suruchi; Kumar, Maneesh; Roy, Sumitabho Deb; Pore, Subrata Kumar; Banerjee, Rajkumar; Mahesh Kumar, Jerald; Thakur, Ram Krishna; Chowdhury, Shantanu

    2014-01-01

    Building molecular correlates of drug resistance in cancer and exploiting them for therapeutic intervention remains a pressing clinical need. To identify factors that impact drug resistance herein we built a model that couples inherent cell-based response toward drugs with transcriptomes of resistant/sensitive cells. To test this model, we focused on a group of genes called metastasis suppressor genes (MSGs) that influence aggressiveness and metastatic potential of cancers. Interestingly, modeling of 84 000 drug response transcriptome combinations predicted multiple MSGs to be associated with resistance of different cell types and drugs. As a case study, on inducing MSG levels in a drug resistant breast cancer line resistance to anticancer drugs caerulomycin, camptothecin and topotecan decreased by more than 50-60%, in both culture conditions and also in tumors generated in mice, in contrast to control un-induced cells. To our knowledge, this is the first demonstration of engineered reversal of drug resistance in cancer cells based on a model that exploits inherent cellular response profiles.

  9. Transglutaminase induction by various cell death and apoptosis pathways.

    Science.gov (United States)

    Fesus, L; Madi, A; Balajthy, Z; Nemes, Z; Szondy, Z

    1996-10-31

    Clarification of the molecular details of forms of natural cell death, including apoptosis, has become one of the most challenging issues of contemporary biomedical sciences. One of the effector elements of various cell death pathways is the covalent cross-linking of cellular proteins by transglutaminases. This review will discuss the accumulating data related to the induction and regulation of these enzymes, particularly of tissue type transglutaminase, in the molecular program of cell death. A wide range of signalling pathways can lead to the parallel induction of apoptosis and transglutaminase, providing a handle for better understanding the exact molecular interactions responsible for the mechanism of regulated cell death.

  10. H-2-incompatible bone marrow chimeras produce donor-H-2-restricted Ly-2 suppressor T-cell factor(s)

    International Nuclear Information System (INIS)

    Noguchi, M.; Onoe, K.; Ogasawara, M.; Iwabuchi, K.; Geng, L.; Ogasawara, K.; Good, R.A.; Morikawa, K.

    1985-01-01

    To study adaptive-differentiation phenomena of T lymphocytes, suppressor T-cell factors (TsF) produced by Ly-2+ splenic T cells from fully allogeneic mouse bone marrow chimeras were analyzed. AKR mice irradiated and reconstituted with B10 marrow cells (B10----AKR chimeras) produced an Ly-2+ TsF after hyperimmunization with sheep erythrocytes. The TsF suppressed primary antibody responses (to sheep erythrocytes) generated with spleen cells of mice of H-2b haplotype but not those of H-2k haplotype. Thus, this suppressor factor was donor-H-2-restricted. The immunoglobulin heavy chain variable region gene (Igh-V)-restricting element was not involved in this form of suppression. Similar results were obtained when TsF from B6----BALB/c and BALB/c----B6 chimeras were analyzed. The TsF from B10----AKR chimeras suppressed responses of B10.A(3R) and B10.A(5R) mice but not those of B10.A(4R). This finding showed that identity between the factor-producing cells and target spleen cells is required on the left-hand side of the E beta locus of the H-2 region and that the putative I-Jb locus is not involved in this form of suppression. The present results support the postulate that post-thymic differentiation in the presence of continued or repeated stimulation with antigen and donor-derived antigen-presenting cells generates donor-H-2-restricted T-cell clones that may predominate within the repertoire of the specific antigen being presented

  11. Reduction of myeloid suppressor cell derived nitric oxide provides a mechanistic basis of lead enhancement of alloreactive CD4+ T cell proliferation

    International Nuclear Information System (INIS)

    Farrer, David G.; Hueber, Sara; Laiosa, Michael D.; Eckles, Kevin G.; McCabe, Michael J.

    2008-01-01

    The persistent environmental toxicant and immunomodulator, lead (Pb), has been proposed to directly target CD4 + T cells. However, our studies suggest that CD4 + T cells are an important functional, yet indirect target. In order to identify the direct target of Pb in the immune system and the potential mechanism of Pb-induced immunotoxicity, myeloid suppressor cells (MSCs) were evaluated for their ability to modulate CD4 + T cell proliferation after Pb exposure. Myeloid suppressor cells regulate the adaptive immune response, in part, by inhibiting the proliferation of CD4 + T cells. It is thought that the mechanism of MSC-dependent regulation involves the release of the bioactive gas, nitric oxide (NO), blocking cell signaling cascades downstream of the IL-2 receptor and thus preventing T cells from entering cell-cycle. In mixed lymphocyte culture (MLC), increasing numbers of MSCs suppressed T cell proliferation in a dose-dependent manner, and this suppression is strikingly abrogated with 5 μM lead (Pb) treatment. The Pb-sensitive MSC population is CD11b + , GR1 + and CD11c - and thus phenotypically consistent with MSCs described in other literature. Inhibition of NO-synthase (NOS), the enzyme responsible for the production of NO, enhanced alloreactive T cell proliferation in MLC. Moreover, Pb attenuated NO production in MLC, and exogenous replacement of NO restored suppression in the presence of Pb. Significantly, MSC from iNOS-/- mice were unable to suppress T cell proliferation. An MSC-derived cell line (MSC-1) also suppressed T cell proliferation in MLC, and Pb disrupted this suppression by attenuating NO production. Additionally, Pb disrupted NO production in MSC-1 cells in response to treatment with interferon-γ (IFN-γ) and LPS or in response to concanavalin A-stimulated splenocytes. However, neither the abundance of protein nor levels of mRNA for the inducible isoform of NOS (iNOS) were altered with Pb treatment. Taken together these data suggest that Pb

  12. The process and promotion of radiation-induced cell death

    International Nuclear Information System (INIS)

    Sasaki, Hiroshi

    1998-01-01

    Radiation-induced cell death is divided into reproductive and interphase death, whose process can be revealed by time-lapse observations. Pedigree analyses of progenies derived from a surviving progenitor cell have shown that moribund cells appear in clusters among cells which are apparently undamaged (lethal sectoring). Sister cell fusion, which likely results from chromosome bridge, is the most frequently observed cell abnormality leading to reproductive death. While interphase death does not occur unless the dose exceeds 10 Gy for low LET radiation such as X-rays, high-LET radiation is very effective at inducing interphase death (RBE: ≅3 at 230 keV/μm). Expression or fixation of potentially lethal damage (PLD) is closely associated with cell cycle events and enhanced by inducing premature chromosome condensation (PCC) at a nonpermissive temperature in tsBN2 cells with a ts-defect in RCC1 protein (a regulator of chromatin condensation) which monitors the completion of DNA replication. Furthermore, higher-order structural changes in nuclear matrix such as induced by leptomycin B, an inhibitor of CRM1 (chromosome region maintenance) protein, also play an important role in the fixation of PLD. (author)

  13. Myeloid-Derived Suppressor Cells Ameliorate Cyclosporine A-Induced Hypertension in Mice.

    Science.gov (United States)

    Chiasson, Valorie L; Bounds, Kelsey R; Chatterjee, Piyali; Manandhar, Lochana; Pakanati, Abhinandan R; Hernandez, Marcos; Aziz, Bilal; Mitchell, Brett M

    2018-01-01

    The calcineurin inhibitor cyclosporine A (CsA) suppresses the immune system but promotes hypertension, vascular dysfunction, and renal damage. CsA decreases regulatory T cells and this contributes to the development of hypertension. However, CsA's effects on another important regulatory immune cell subset, myeloid-derived suppressor cells (MDSCs), is unknown. We hypothesized that augmenting MDSCs would ameliorate the CsA-induced hypertension and vascular and renal injury and dysfunction and that CsA reduces MDSCs in mice. Daily interleukin-33 treatment, which increased MDSC levels, completely prevented CsA-induced hypertension and vascular and renal toxicity. Adoptive transfer of MDSCs from control mice into CsA-treated mice after hypertension was established dose-dependently reduced blood pressure and vascular and glomerular injury. CsA treatment of aortas and kidneys isolated from control mice for 24 hours decreased relaxation responses and increased inflammation, respectively, and these effects were prevented by the presence of MDSCs. MDSCs also prevented the CsA-induced increase in fibronectin in microvascular and glomerular endothelial cells. Last, CsA dose-dependently reduced the number of MDSCs by inhibiting calcineurin and preventing cell proliferation, as other direct calcineurin signaling pathway inhibitors had the same dose-dependent effect. These data suggest that augmenting MDSCs can reduce the cardiovascular and renal toxicity and hypertension caused by CsA. © 2017 American Heart Association, Inc.

  14. UV-Induced Cell Death in Plants

    Science.gov (United States)

    Nawkar, Ganesh M.; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

    2013-01-01

    Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400–700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280–320 nm) and UV-A (320–390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD). PMID:23344059

  15. Status of T- and B-cell cooperation in radiation chimeras: evidence for a suppressor effect

    International Nuclear Information System (INIS)

    Gengozian, N.; Urso, P.

    1976-01-01

    Absolute tolerance may not be in operation in the allogeneic bone marrow chimera, but rather a dynamic state involving interaction not only between the donor and host but also among the donor-lymphoid cells themselves may exist. Whether this observation made in one allogeneic chimera, CD2F 1 → C3BF 1 , will be true for other chimeras (different strain combinations, species) remains to be shown. Thus, the tempo, mode, and requirement for the generation of suppressor T cells are factors that may vary for any specific allogeneic bone marrow transplant. Finally, the manner and degree to which the tolerance-inducing mechanism may affect T- and B-cell functions of the chimera with respect to third-party antigens are yet to be determined

  16. Expression of death receptor 4 induces caspase-independent cell death in MMS-treated yeast.

    Science.gov (United States)

    Kang, Mi-Sun; Lee, Sung-Keun; Park, Chang-Shin; Kang, Ju-Hee; Bae, Sung-Ho; Yu, Sung-Lim

    2008-11-14

    DR4, a tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, is a key element in the extrinsic pathway of TRAIL/TRAIL receptor-related apoptosis that exerts a preferential toxic effect against tumor cells. However, TRAIL and DR4 are expressed in various normal cells, and recent studies indicate that DR4 has a number of non-apoptotic functions. In this study, we evaluated the effects of human DR4 expression in yeast to determine the function of DR4 in normal cells. The expression of DR4 in yeast caused G1 arrest, which resulted in transient growth inhibition. Moreover, treatment of DR4-expressing yeast with a DNA damaging agent, MMS, elicited drastic, and sustained cell growth inhibition accompanied with massive apoptotic cell death. Further analysis revealed that cell death in the presence of DNA damage and DR4 expression was not dependent on the yeast caspase, YCA1. Taken together, these results indicate that DR4 triggers caspase-independent programmed cell death during the response of normal cells to DNA damage.

  17. (−)-Xanthatin Selectively Induces GADD45γ and Stimulates Caspase-Independent Cell Death in Human Breast Cancer MDA-MB-231 Cells

    Science.gov (United States)

    Takeda, Shuso; Matsuo, Kazumasa; Yaji, Kentaro; Okajima-Miyazaki, Shunsuke; Harada, Mari; Miyoshi, Hiroko; Okamoto, Yoshiko; Amamoto, Toshiaki; Shindo, Mitsuru; Omiecinski, Curtis J.; Aramaki, Hironori

    2014-01-01

    exo-Methylene lactone group-containing compounds, such as (−)-xanthatin, are present in a large variety of biologically active natural products, including extracts of Xanthium strumarium (Cocklebur). These substances are reported to possess diverse functional activities, exhibiting anti-inflammatory, antimalarial, and anticancer potential. In this study, we synthesized six structurally related xanthanolides containing exo-methylene lactone moieties, including (−)-xanthatin and (+)-8-epi-xanthatin, and examined the effects of these chemically defined substances on the highly aggressive and farnesyltransferase inhibitor (FTI)-resistant MDA-MB-231 cancer cell line. The results obtained demonstrate that (−)-xanthatin was a highly effective inhibitor of MDA-MB-231 cell growth, inducing caspase-independent cell death, and that these effects were independent of FTase inhibition. Further, our results show that among the GADD45 isoforms, GADD45γ was selectively induced by (−)-xanthatin and that GADD45γ-primed JNK and p38 signaling pathways are, at least in part, involved in mediating the growth inhibition and potential anticancer activities of this agent. Given that GADD45γ is becoming increasingly recognized for its tumor suppressor function, the results presented here suggest the novel possibility that (−)-xanthatin may have therapeutic value as a selective inducer of GADD45γ in human cancer cells, in particular in FTI-resistant aggressive breast cancers. PMID:21568272

  18. Inducible cell death in plant immunity

    DEFF Research Database (Denmark)

    Hofius, Daniel; Tsitsigiannis, Dimitrios I; Jones, Jonathan D G

    2006-01-01

    Programmed cell death (PCD) occurs during vegetative and reproductive plant growth, as typified by autumnal leaf senescence and the terminal differentiation of the endosperm of cereals which provide our major source of food. PCD also occurs in response to environmental stress and pathogen attack......, and these inducible PCD forms are intensively studied due their experimental tractability. In general, evidence exists for plant cell death pathways which have similarities to the apoptotic, autophagic and necrotic forms described in yeast and metazoans. Recent research aiming to understand these pathways...

  19. Mitochondrial apoptotic pathways induced by Drosophila programmed cell death regulators

    International Nuclear Information System (INIS)

    Claveria, Cristina; Torres, Miguel

    2003-01-01

    Multicellular organisms eliminate unwanted or damaged cells by cell death, a process essential to the maintenance of tissue homeostasis. Cell death is a tightly regulated event, whose alteration by excess or defect is involved in the pathogenesis of many diseases such as cancer, autoimmune syndromes, and neurodegenerative processes. Studies in model organisms, especially in the nematode Caenorhabditis elegans, have been crucial in identifying the key molecules implicated in the regulation and execution of programmed cell death. In contrast, the study of cell death in Drosophila melanogaster, often an excellent model organism, has identified regulators and mechanisms not obviously conserved in other metazoans. Recent molecular and cellular analyses suggest, however, that the mechanisms of action of the main programmed cell death regulators in Drosophila include a canonical mitochondrial pathway

  20. Sickle cell trait and sudden death--bringing it home.

    Science.gov (United States)

    Mitchell, Bruce L.

    2007-01-01

    Sickle cell trait continues to be the leading cause of sudden death for young African Americans in military basic training and civilian organized sports. The syndrome may have caused the death of up to 10 college football players since 1974 and, as recently as 2000, was suspected as the cause of death of three U.S. Army recruits. The penal military-style boot camps in the United States and the recent death of two teenagers with sickle cell trait merits renewed vigor in the education of athletic instructors, the military and the public about conditions associated with sudden death in individuals with sickle cell trait. Images Figure 1 Figure 2 PMID:17393956

  1. Regulatory T cells as suppressors of anti-tumor immunity: Role of metabolism.

    Science.gov (United States)

    De Rosa, Veronica; Di Rella, Francesca; Di Giacomo, Antonio; Matarese, Giuseppe

    2017-06-01

    Novel concepts in immunometabolism support the hypothesis that glucose consumption is also used to modulate anti-tumor immune responses, favoring growth and expansion of specific cellular subsets defined in the past as suppressor T cells and currently reborn as regulatory T (Treg) cells. During the 1920s, Otto Warburg and colleagues observed that tumors consumed high amounts of glucose compared to normal tissues, even in the presence of oxygen and completely functioning mitochondria. However, the role of the Warburg Effect is still not completely understood, particularly in the context of an ongoing anti-tumor immune response. Current experimental evidence suggests that tumor-derived metabolic restrictions can drive T cell hyporesponsiveness and immune tolerance. For example, several glycolytic enzymes, deregulated in cancer, contribute to tumor progression independently from their canonical metabolic activity. Indeed, they can control apoptosis, gene expression and activation of specific intracellular pathways, thus suggesting a direct link between metabolic switches and pro-tumorigenic transcriptional programs. Focus of this review is to define the specific metabolic pathways controlling Treg cell immunobiology in the context of anti-tumor immunity and tumor progression. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Axl acts as a tumor suppressor by regulating LIGHT expression in T lymphoma

    Science.gov (United States)

    Young, Kon-Ji; Park, A-Reum; Choi, Ha-Rim; Lee, Hwa-Youn; Kim, Su-Man; Chung, Byung Yeoup; Park, Chul-Hong; Choi, Hyo Jin; Ko, Young-Hyeh; Bai, Hyoung-Woo; Kang, Hyung-Sik

    2017-01-01

    Axl is an oncogenic receptor tyrosine kinase that plays a role in many cancers. LIGHT (Lymphotoxin-related inducible ligand that competes for glycoprotein D binding to herpesvirus entry mediator on T cells) is a ligand that induces robust anti-tumor immunity by enhancing the recruitment and activation of effector immune cells at tumor sites. We observed that mouse EL4 and human Jurkat T lymphoma cells that stably overexpressed Axl also showed high expression of LIGHT. When Jurkat-Axl cells were treated with Gas6, a ligand for Axl, LIGHT expression was upregulated through activation of the PI3K/AKT signaling pathway and transcriptional induction by Sp1. The lytic activity of cytotoxic T lymphocytes and natural killer cells was enhanced by EL4-Axl cells. In addition, tumor volume and growth were markedly reduced due to enhanced apoptotic cell death in EL4-Axl tumor-bearing mice as compared to control mice. We also observed upregulated expression of CCL5 and its receptor, CCR5, and enhanced intratumoral infiltration of cytotoxic T lymphocytes and natural killer cells in EL4-Axl-bearing mice as compared to mock controls. These data strongly suggested that Axl exerts novel tumor suppressor effects by inducing upregulation of LIGHT in the tumor microenvironment of T lymphoma. PMID:28423548

  3. Photoreactivation of conversion and de novo suppressor mutation in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Bockrath, R C; Plamer, J E [Indiana Univ., Indianapolis (USA). Dept. of Microbiology

    1977-04-01

    Studies of mutagenesis and photoreactivation in various E.coli strains have shown that conversion mutation of a mutant containing an amber suppressor to one containing an ochre suppressor is sensitive to photoreactivation. Direct photoreactivation by photoreactivating light (PRL) after uv mutagenesis reduced mutation frequencies by a factor of about 2 for each minute of exposure during the first 5 to 8 min of exposure for cells with normal repair capacity. Conversion and potential de novo suppressor mutations were about equally sensitive. For conversion, the sensitivities to PRL were identical in the repair-normal and excisions-repair-deficient strains. For de novo suppressor mutation, the rate of mutation frequency reduction by PRL in the repair-deficient strain was about one-half that in the other strains. The results suggest that ultraviolet radiation produces both de novo suppressor mutation and conversion at the sup(E,B) locus by photoreversible pyrimidine dimers in the DNA. The causative dimers could be Thy()Cyt dimers in the transcribed strand or the non-transcribed strand, respectively.

  4. Bifurcate effects of glucose on caspase-independent cell death during hypoxia

    International Nuclear Information System (INIS)

    Aki, Toshihiko; Nara, Akina; Funakoshi, Takeshi; Uemura, Koichi

    2010-01-01

    We investigated the effect of glucose on hypoxic death of rat cardiomyocyte-derived H9c2 cells and found that there is an optimal glucose concentration for protection against hypoxic cell death. Hypoxic cell death in the absence of glucose is accompanied by rapid ATP depletion, release of apoptosis-inducing factor from mitochondria, and nuclear chromatin condensation, all of which are inhibited by glucose in a dose-dependent manner. In contrast, excessive glucose also induces hypoxic cell death that is not accompanied by these events, suggesting a change in the mode of cell death between hypoxic cells with and without glucose supplementation.

  5. Systemic T Cells Immunosuppression of Glioma Stem Cell-Derived Exosomes Is Mediated by Monocytic Myeloid-Derived Suppressor Cells.

    Directory of Open Access Journals (Sweden)

    Rossana Domenis

    Full Text Available A major contributing factor to glioma development and progression is its ability to evade the immune system. Nano-meter sized vesicles, exosomes, secreted by glioma-stem cells (GSC can act as mediators of intercellular communication to promote tumor immune escape. Here, we investigated the immunomodulatory properties of GCS-derived exosomes on different peripheral immune cell populations. Healthy donor peripheral blood mononuclear cells (PBMCs stimulated with anti-CD3, anti-CD28 and IL-2, were treated with GSC-derived exosomes. Phenotypic characterization, cell proliferation, Th1/Th2 cytokine secretion and intracellular cytokine production were analysed by distinguishing among effector T cells, regulatory T cells and monocytes. In unfractionated PBMCs, GSC-derived exosomes inhibited T cell activation (CD25 and CD69 expression, proliferation and Th1 cytokine production, and did not affect cell viability or regulatory T-cell suppression ability. Furthermore, exosomes were able to enhance proliferation of purified CD4+ T cells. In PBMCs culture, glioma-derived exosomes directly promoted IL-10 and arginase-1 production and downregulation of HLA-DR by unstimulated CD14+ monocytic cells, that displayed an immunophenotype resembling that of monocytic myeloid-derived suppressor cells (Mo-MDSCs. Importantly, the removal of CD14+ monocytic cell fraction from PBMCs restored T-cell proliferation. The same results were observed with exosomes purified from plasma of glioblastoma patients. Our results indicate that glioma-derived exosomes suppress T-cell immune response by acting on monocyte maturation rather than on direct interaction with T cells. Selective targeting of Mo-MDSC to treat glioma should be considered with regard to how immune cells allow the acquirement of effector functions and therefore counteracting tumor progression.

  6. TFPI-2 is a putative tumor suppressor gene frequently inactivated by promoter hypermethylation in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Wang, Shumin; Ma, Ning; Murata, Mariko; Huang, Guangwu; Zhang, Zhe; Xiao, Xue; Zhou, Xiaoying; Huang, Tingting; Du, Chunping; Yu, Nana; Mo, Yingxi; Lin, Longde; Zhang, Jinyan

    2010-01-01

    Epigenetic silencing of tumor suppressor genes play important roles in NPC tumorgenesis. Tissue factor pathway inhibitor-2 (TFPI-2), is a protease inhibitor. Recently, TFPI-2 was suggested to be a tumor suppressor gene involved in tumorigenesis and metastasis in some cancers. In this study, we investigated whether TFPI-2 was inactivated epigenetically in nasopharyngeal carcinoma (NPC). Transcriptional expression levels of TFPI-2 was evaluated by RT-PCR. Methylation status were investigated by methylation specific PCR and bisulfate genomic sequencing. The role of TFPI-2 as a tumor suppressor gene in NPC was addressed by re-introducing TFPI-2 expression into the NPC cell line CNE2. TFPI-2 mRNA transcription was inactivated in NPC cell lines. TFPI-2 was aberrantly methylated in 66.7% (4/6) NPC cell lines and 88.6% (62/70) of NPC primary tumors, but not in normal nasopharyngeal epithelia. TFPI-2 expression could be restored in NPC cells after demethylation treatment. Ectopic expression of TFPI-2 in NPC cells induced apoptosis and inhibited cell proliferation, colony formation and cell migration. Epigenetic inactivation of TFPI-2 by promoter hypermethylation is a frequent and tumor specific event in NPC. TFPI-2 might be considering as a putative tumor suppressor gene in NPC

  7. C/EBPβ LIP augments cell death by inducing osteoglycin.

    Science.gov (United States)

    Wassermann-Dozorets, Rina; Rubinstein, Menachem

    2017-04-06

    Many types of tumor cell are devoid of the extracellular matrix proteoglycan osteoglycin (Ogn), but its role in tumor biology is poorly studied. Here we show that RNAi of Ogn attenuates stress-triggered cell death, whereas its overexpression increases cell death. We found that the transcription factor C/EBPβ regulates the expression of Ogn. C/EBPβ is expressed as a full-length, active form (LAP) and as a truncated, dominant-negative form (LIP), and the LIP/LAP ratio is positively correlated with the extent of cell death under stress. For example, we reported that drug-resistant tumor cells lack LIP altogether, and its supplementation abolished their resistance to chemotherapy and to endoplasmic reticulum (ER) stress. Here we further show that elevated LIP/LAP ratio robustly increased Ogn expression and cell death under stress by modulating the mitogen-activated protein kinase/activator protein 1 pathway (MAPK/AP-1). Our findings suggest that LIP deficiency renders tumor cell resistant to ER stress by preventing the induction of Ogn.

  8. Bee Venom Protects against Rotenone-Induced Cell Death in NSC34 Motor Neuron Cells

    Directory of Open Access Journals (Sweden)

    So Young Jung

    2015-09-01

    Full Text Available Rotenone, an inhibitor of mitochondrial complex I of the mitochondrial respiratory chain, is known to elevate mitochondrial reactive oxygen species and induce apoptosis via activation of the caspase-3 pathway. Bee venom (BV extracted from honey bees has been widely used in oriental medicine and contains melittin, apamin, adolapin, mast cell-degranulating peptide, and phospholipase A2. In this study, we tested the effects of BV on neuronal cell death by examining rotenone-induced mitochondrial dysfunction. NSC34 motor neuron cells were pretreated with 2.5 μg/mL BV and stimulated with 10 μM rotenone to induce cell toxicity. We assessed cell death by Western blotting using specific antibodies, such as phospho-ERK1/2, phospho-JNK, and cleaved capase-3 and performed an MTT assay for evaluation of cell death and mitochondria staining. Pretreatment with 2.5 μg/mL BV had a neuroprotective effect against 10 μM rotenone-induced cell death in NSC34 motor neuron cells. Pre-treatment with BV significantly enhanced cell viability and ameliorated mitochondrial impairment in rotenone-treated cellular model. Moreover, BV treatment inhibited the activation of JNK signaling and cleaved caspase-3 related to cell death and increased ERK phosphorylation involved in cell survival in rotenone-treated NSC34 motor neuron cells. Taken together, we suggest that BV treatment can be useful for protection of neurons against oxidative stress or neurotoxin-induced cell death.

  9. Cell death triggered by alpha-emitting {sup 213}Bi-immunoconjugates in HSC45-M2 gastric cancer cells is different from apoptotic cell death

    Energy Technology Data Exchange (ETDEWEB)

    Seidl, Christof; Schroeck, Hedwig; Seidenschwang, Sabine; Beck, Roswitha; Schwaiger, Markus; Senekowitsch-Schmidtke, Reingard [Technische Universitaet Muenchen, Department of Nuclear Medicine, Munich (Germany); Schmid, Ernst [National Research Center for Environment and Health, Institute of Radiation Biology, GSF, Neuherberg (Germany); Abend, Michael [German Armed Forces, Institute of Radiobiology, Munich (Germany); Becker, Karl-Friedrich [Technische Universitaet Muenchen, Institute of Pathology, Munich (Germany); National Research Center for Environment and Health, Institute of Pathology, GSF, Neuherberg (Germany); National Research Center for Environment and Health, Institute of Molecular Immunology, GSF, Munich (Germany); Apostolidis, Christos; Nikula, Tuomo K. [European Commission, Institute for Transuranium Elements, Karlsruhe (Germany); Kremmer, Elisabeth [National Research Center for Environment and Health, Institute of Molecular Immunology, GSF, Munich (Germany)

    2005-03-01

    Radioimmunotherapy with {alpha}-particle-emitting nuclides, such as{sup 213}Bi, is a promising concept for the elimination of small tumour nodules or single disseminated tumour cells. The aim of this study was to investigate cellular damage and the mode of cell death triggered by {sup 213}Bi-immunoconjugates. Human gastric cancer cells (HSC45-M2) expressing d9-E-cadherin were incubated with different levels of activity of {sup 213}Bi-d9MAb targeting d9-E-cadherin and {sup 213}Bi-d8MAb, which does not bind to d9-E-cadherin. Micronucleated (M) cells, abnormal (A) cells and apoptotic (A) [(MAA)] cells were scored microscopically in the MAA assay following fluorescent staining of nuclei and cytoplasm. Chromosomal aberrations were analysed microscopically following Giemsa staining. The effect of z-VAD-fmk, known to inhibit apoptosis, on the prevention of cell death was investigated following treatment of HSC45-M2 cells with sorbitol as well as {sup 213}Bi-d9MAb. Activation of caspase 3 after incubation of HSC45-M2 cells with both sorbitol and {sup 213}Bi-d9MAb was analysed via Western blotting. Following incubation of HSC45-M2 human gastric cancer cells expressing d9-E-cadherin with {sup 213}Bi-d9MAb the number of cells killed increased proportional to the applied activity concentration. Microscopically visible effects of {alpha}-irradiation of HSC45-M2 cells were formation of micronuclei and severe chromosomal aberrations. Preferential induction of these lesions with specific {sup 213}Bi-d9MAb compared with unspecific {sup 213}Bi-d8MAb (not targeting d9-E-cadherin) was not observed if the number of floating, i.e. unbound {sup 213}Bi-immunoconjugates per cell exceeded 2 x 10{sup 4}, most likely due to intense crossfire. In contrast to sorbitol-induced cell death, cell death triggered by {sup 213}Bi-immunoconjugates was independent of caspase 3 activation and could not be inhibited by z-VAD-fmk, known to suppress the apoptotic pathway. {sup 213}Bi-immunoconjugates seem

  10. Sigma-2 ligands and PARP inhibitors synergistically trigger cell death in breast cancer cells

    International Nuclear Information System (INIS)

    McDonald, Elizabeth S.; Mankoff, Julia; Makvandi, Mehran; Chu, Wenhua; Chu, Yunxiang; Mach, Robert H.; Zeng, Chenbo

    2017-01-01

    The sigma-2 receptor is overexpressed in proliferating cells compared to quiescent cells and has been used as a target for imaging solid tumors by positron emission tomography. Recent work has suggested that the sigma-2 receptor may also be an effective therapeutic target for cancer therapy. Poly (ADP-ribose) polymerase (PARP) is a family of enzymes involved in DNA damage response. In this study, we looked for potential synergy of cytotoxicity between PARP inhibitors and sigma-2 receptor ligands in breast cancer cell lines. We showed that the PARP inhibitor, YUN3-6, sensitized mouse breast cancer cell line, EMT6, to sigma-2 receptor ligand (SV119, WC-26, and RHM-138) induced cell death determined by cell viability assay and colony forming assay. The PARP inhibitor, olaparib, sensitized tumor cells to a different sigma-2 receptor ligand SW43-induced apoptosis and cell death in human triple negative cell line, MDA-MB-231. Olaparib inhibited PARP activity and cell proliferation, and arrested cells in G2/M phase of the cell cycle in MDA-MB-231 cells. Subsequently cells became sensitized to SW43 induced cell death. In conclusion, the combination of sigma-2 receptor ligands and PARP inhibitors appears to hold promise for synergistically triggering cell death in certain types of breast cancer cells and merits further investigation. - Highlights: • PARPi, YUN3-6 and olaparib, and σ2 ligands, SV119 and SW43, were evaluated. • Mouse and human breast cancer cells, EMT6 and MDA-MB-231 respectively, were used. • YUN3-6 and SV119 synergistically triggered cell death in EMT6 cells. • Olaparib and SW43 additively triggered cell death in MDA-MB-231 cells. • Olaparib arrested cells in G2/M in MDA-MB-231 cells.

  11. Effect of hemopoietic microenvironment on splenic suppressor macrophages in congenitally anemic mice of genotype Sl/Sld

    International Nuclear Information System (INIS)

    Shibata, Y.; Volkman, A.

    1985-01-01

    Mechanisms underlying mononuclear phagocyte specialization are being probed by studying suppressor macrophages (M phi) as a reference population in mouse models with impaired blood monocyte formation. Splenic suppressor M phi, defined by PGE-mediated inhibition of Con A-induced T lymphocyte proliferation are induced by the i.p. administration of Corynebacterium parvum (CP). Mice severely depleted of bone marrow and blood monocytes by treatment with 89Sr fail to show this suppressor M phi response to CP, although M phi-forming stem cells, assessed as splenic M-CFC in vitro, are increased 20-fold. These observations suggest that radiosensitive bone marrow stem cells are necessary for the generation of both suppressor M phi and monocytes and that one such stem cell may be common to both types of mononuclear phagocytes. This notion was explored further by employing congenitally anemic mice of the genotype S1/S1d in which the hemopoietic microenvironment is genetically defective and thus unable to support the proliferation, differentiation, and function of stem cells. The congenital defect was found to be additionally expressed in the S1/S1d mouse by a monocytopenia of less than 10% of the values in normal congenic littermate controls and by the failure of splenic M-CFC to increase in response to CP. PGE-producing suppressor M phi expressing Fc gamma 2b receptors, however, were induced by CP in S1/S1d mice with no significant diminution of suppressor activity. These data establish the fact that significant impairment of the formation of monocytes is part of the overall hemopoietic defect in S1/S1d mice. PGE-producing suppressor M phi, however, were inducible at normal functional levels in the presence of a profound monocytopenia, and therefore appear to be independent of the mechanisms that regulate blood monocyte formation

  12. Characterization of a serine protease-mediated cell death program activated in human leukemia cells

    International Nuclear Information System (INIS)

    O'Connell, A.R.; Holohan, C.; Torriglia, A.; Lee, B.F.; Stenson-Cox, C.

    2006-01-01

    Tightly controlled proteolysis is a defining feature of apoptosis and caspases are critical in this regard. Significant roles for non-caspase proteases in cell death have been highlighted. Staurosporine causes a rapid induction of apoptosis in virtually all mammalian cell types. Numerous studies demonstrate that staurosporine can activate cell death under caspase-inhibiting circumstances. The aim of this study was to investigate the proteolytic mechanisms responsible for cell death under these conditions. To that end, we show that inhibitors of serine proteases can delay cell death in one such system. Furthermore, through profiling of proteolytic activation, we demonstrate, for the first time, that staurosporine activates a chymotrypsin-like serine protease-dependent cell death in HL-60 cells independently, but in parallel with the caspase controlled systems. Features of the serine protease-mediated system include cell shrinkage and apoptotic morphology, regulation of caspase-3, altered nuclear morphology, generation of an endonuclease and DNA degradation. We also demonstrate a staurosporine-induced activation of a putative 16 kDa chymotrypsin-like protein during apoptosis

  13. Characterization of the myeloid-derived suppressor cell subset regulated by NK cells in malignant lymphoma.

    Science.gov (United States)

    Sato, Yusuke; Shimizu, Kanako; Shinga, Jun; Hidaka, Michihiro; Kawano, Fumio; Kakimi, Kazuhiro; Yamasaki, Satoru; Asakura, Miki; Fujii, Shin-Ichiro

    2015-03-01

    Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population with the ability to suppress immune responses and are currently classified into three distinct MDSC subsets: monocytic, granulocytic and non-monocytic, and non-granulocytic MDSCs. Although NK cells provide an important first-line defense against newly transformed cancer cells, it is unknown whether NK cells can regulate MDSC populations in the context of cancer. In this study, we initially found that the frequency of MDSCs in non-Hodgkin lymphoma (NHL) patients was increased and inversely correlated with that of NK cells, but not that of T cells. To investigate the regulation of MDSC subsets by NK cells, we used an EL4 murine lymphoma model and found the non-monocytic and non-granulocytic MDSC subset, i.e., Gr1 + CD11b + Ly6G med Ly6C med MDSC, is increased after NK cell depletion. The MDSC population that expresses MHC class II, CD80, CD124, and CCR2 is regulated mainly by CD27 + CD11b + NK cells. In addition, this MDSC subset produces some immunosuppressive cytokines, including IL-10 but not nitric oxide (NO) or arginase. We also examined two subsets of MDSCs (CD14 + HLA-DR - and CD14 - HLA-DR - MDSC) in NHL patients and found that higher IL-10-producing CD14 + HLA-DR - MDSC subset can be seen in lymphoma patients with reduced NK cell frequency in peripheral blood. Our analyses of MDSCs in this study may enable a better understanding of how MDSCs manipulate the tumor microenvironment and are regulated by NK cells in patients with lymphoma.

  14. How Kidney Cell Death Induces Renal Necroinflammation.

    Science.gov (United States)

    Mulay, Shrikant R; Kumar, Santhosh V; Lech, Maciej; Desai, Jyaysi; Anders, Hans-Joachim

    2016-05-01

    The nephrons of the kidney are independent functional units harboring cells of a low turnover during homeostasis. As such, physiological renal cell death is a rather rare event and dead cells are flushed away rapidly with the urinary flow. Renal cell necrosis occurs in acute kidney injuries such as thrombotic microangiopathies, necrotizing glomerulonephritis, or tubular necrosis. All of these are associated with intense intrarenal inflammation, which contributes to further renal cell loss, an autoamplifying process referred to as necroinflammation. But how does renal cell necrosis trigger inflammation? Here, we discuss the role of danger-associated molecular patterns (DAMPs), mitochondrial (mito)-DAMPs, and alarmins, as well as their respective pattern recognition receptors. The capacity of DAMPs and alarmins to trigger cytokine and chemokine release initiates the recruitment of leukocytes into the kidney that further amplify necroinflammation. Infiltrating neutrophils often undergo neutrophil extracellular trap formation associated with neutrophil death or necroptosis, which implies a release of histones, which act not only as DAMPs but also elicit direct cytotoxic effects on renal cells, namely endothelial cells. Proinflammatory macrophages and eventually cytotoxic T cells further drive kidney cell death and inflammation. Dissecting the molecular mechanisms of necroinflammation may help to identify the best therapeutic targets to limit nephron loss in kidney injury. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Radiation-induced cell death by chromatin loss

    International Nuclear Information System (INIS)

    Campbell, I.R.; Warenius, H.M.

    1989-01-01

    A model is proposed which relates reproductive death of cells caused by radiation to loss of chromatin at cell division. This loss of chromatin can occur through chromosomal deletions or through the formation of asymmetrical chromosomal exchanges. It is proposed that smaller doses of radiation produce fewer chromatin breaks, which are more likely to be accurately repaired, compared with larger doses. Consequently, smaller doses of radiation are less efficient in causing cell death, leading to a shoulder on the cell survival curve. Experimental evidence supports this model, and the fit between the derived formula and experimental cell survival curves is good. The derived formula approximates to the linear-quadratic equation at low doses of radiation. (author)

  16. Activated NKT cells facilitated functional switch of myeloid-derived suppressor cells at inflammation sites in fulminant hepatitis mice.

    Science.gov (United States)

    Wu, Danxiao; Shi, Yu; Wang, Cheng; Chen, Hanwen; Liu, Qiaoyun; Liu, Jianhua; Zhang, Lihuang; Wu, Yihua; Xia, Dajing

    2017-02-01

    Myeloid-derived suppressor cells (MDSCs) confer immunosuppressive properties, but their roles in fulminant hepatitis have not been well defined. In this study, we systematically examined the distribution of MDSCs in bone marrow (BM), liver and spleen, and their functional and differentiation status in an acute fulminant hepatitis mouse model induced by lipopolysaccharide and D-galactosamine (LPS-GalN). Moreover, the interaction between NKT cells and MDSCs was determined. Our study revealed that BM contained the largest pool of MDSCs during pathogenesis of fulminant hepatitis compared with liver and spleen. MDSCs in liver/spleen expressed higher levels of chemokine receptors such as CCR2, CX3CR1 and CXCR2. At inflamed tissues such as liver or spleen, activated NKT cells induced differentiation of MDSCs through cell-cell interaction, which markedly dampened the immunosuppressive effects and promoted MDSCs to produce pro-inflammatory cytokines and activate inflammatory cells. Our findings thus demonstrated an unexpected pro-inflammatory state for MDSCs, which was mediated by the activated NKT cells that precipitated the differentiation and functional evolution of these MDSCs at sites of inflammation. Copyright © 2016. Published by Elsevier GmbH.

  17. Jasmonic acid signaling modulates ozone-induced hypersensitive cell death.

    Science.gov (United States)

    Rao, M V; Lee, H; Creelman, R A; Mullet, J E; Davis, K R

    2000-09-01

    Recent studies suggest that cross-talk between salicylic acid (SA)-, jasmonic acid (JA)-, and ethylene-dependent signaling pathways regulates plant responses to both abiotic and biotic stress factors. Earlier studies demonstrated that ozone (O(3)) exposure activates a hypersensitive response (HR)-like cell death pathway in the Arabidopsis ecotype Cvi-0. We now have confirmed the role of SA and JA signaling in influencing O(3)-induced cell death. Expression of salicylate hydroxylase (NahG) in Cvi-0 reduced O(3)-induced cell death. Methyl jasmonate (Me-JA) pretreatment of Cvi-0 decreased O(3)-induced H(2)O(2) content and SA concentrations and completely abolished O(3)-induced cell death. Cvi-0 synthesized as much JA as did Col-0 in response to O(3) exposure but exhibited much less sensitivity to exogenous Me-JA. Analyses of the responses to O(3) of the JA-signaling mutants jar1 and fad3/7/8 also demonstrated an antagonistic relationship between JA- and SA-signaling pathways in controlling the magnitude of O(3)-induced HR-like cell death.

  18. Neem leaf glycoprotein prevents post-surgical sarcoma recurrence in Swiss mice by differentially regulating cytotoxic T and myeloid-derived suppressor cells.

    Directory of Open Access Journals (Sweden)

    Madhurima Sarkar

    Full Text Available Post-surgical tumor recurrence is a common problem in cancer treatment. In the present study, the role of neem leaf glycoprotein (NLGP, a novel immunomodulator, in prevention of post-surgical recurrence of solid sarcoma was examined. Data suggest that NLGP prevents tumor recurrence after surgical removal of sarcoma in Swiss mice and increases their tumor-free survival time. In NLGP-treated tumor-free mice, increased cytotoxic CD8+ T cells and a decreased population of suppressor cells, especially myeloid-derived suppressor cells (MDSCs was observed. NLGP-treated CD8+ T cells showed greater cytotoxicity towards tumor-derived MDSCs and supernatants from the same CD8+ T cell culture caused upregulation of FasR and downregulation of cFLIP in MDSCs. To elucidate the role of CD8+ T cells, specifically in association with the downregulation in MDSCs, CD8+ T cells were depleted in vivo before NLGP immunization in surgically tumor removed mice and tumor recurrence was noted. These mice also exhibited increased MDSCs along with decreased levels of Caspase 3, Caspase 8 and increased cFLIP expression. In conclusion, it can be stated that NLGP, by activating CD8+ T cells, down regulates the proportion of MDSCs. Accordingly, suppressive effects of MDSCs on CD8+ T cells are minimized and optimum immune surveillance in tumor hosts is maintained to eliminate the residual tumor mass appearing during recurrence.

  19. The p75{sup NTR} tumor suppressor induces cell cycle arrest facilitating caspase mediated apoptosis in prostate tumor cells

    Energy Technology Data Exchange (ETDEWEB)

    Khwaja, Fatima [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20057-1436 (United States); Tabassum, Arshia [Toronto Western Hospital, Toronto, ON, M5T258 (Canada); Allen, Jeff [National Center for Complementary and Alternative Medicine, N.I.H., Bethesda, MD 20892 (United States); Djakiew, Daniel [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20057-1436 (United States) and Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057-1436 (United States)

    2006-03-24

    The p75 neurotrophin receptor (p75{sup NTR}) is a death receptor which belongs to the tumor necrosis factor receptor super-family of membrane proteins. This study shows that p75{sup NTR} retarded cell cycle progression by induced accumulation of cells in G0/G1 and a reduction in the S phase of the cell cycle. The rescue of tumor cells from cell cycle progression by a death domain deleted ({delta}DD) dominant-negative antagonist of p75{sup NTR} showed that the death domain transduced anti-proliferative activity in a ligand-independent manner. Conversely, addition of NGF ligand rescued retardation of cell cycle progression with commensurate changes in components of the cyclin/cdk holoenzyme complex. In the absence of ligand, p75{sup NTR}-dependent cell cycle arrest facilitated an increase in apoptotic nuclear fragmentation of the prostate cancer cells. Apoptosis of p75{sup NTR} expressing cells occurred via the intrinsic mitochondrial pathway leading to a sequential caspase-9 and -7 cascade. Since the death domain deleted dominant-negative antagonist of p75{sup NTR} rescued intrinsic caspase associated apoptosis in PC-3 cells, this shows p75{sup NTR} was integral to ligand independent induction of apoptosis. Moreover, the ability of ligand to ameliorate the p75{sup NTR}-dependent intrinsic apoptotic cascade indicates that NGF functioned as a survival factor for p75{sup NTR} expressing prostate cancer cells.

  20. Hydrogen Peroxide-induced Cell Death in Arabidopsis : Transcriptional and Mutant Analysis Reveals a Role of an Oxoglutarate-dependent Dioxygenase Gene in the Cell Death Process

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Minkov, Ivan N.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide is a major regulator of plant programmed cell death (PCD) but little is known about the downstream genes from the H2O2-signaling network that mediate the cell death. To address this question, a novel system for studying H2O2-induced programmed cell death in Arabidopsis thaliana was

  1. TIG3 tumor suppressor-dependent organelle redistribution and apoptosis in skin cancer cells.

    Directory of Open Access Journals (Sweden)

    Tiffany M Scharadin

    Full Text Available TIG3 is a tumor suppressor protein that limits keratinocyte survival during normal differentiation. It is also important in cancer, as TIG3 level is reduced in tumors and in skin cancer cell lines, suggesting that loss of expression may be required for cancer cell survival. An important goal is identifying how TIG3 limits cell survival. In the present study we show that TIG3 expression in epidermal squamous cell carcinoma SCC-13 cells reduces cell proliferation and promotes morphological and biochemical apoptosis. To identify the mechanism that drives these changes, we demonstrate that TIG3 localizes near the centrosome and that pericentrosomal accumulation of TIG3 alters microtubule and microfilament organization and organelle distribution. Organelle accumulation at the centrosome is a hallmark of apoptosis and we demonstrate that TIG3 promotes pericentrosomal organelle accumulation. These changes are associated with reduced cyclin D1, cyclin E and cyclin A, and increased p21 level. In addition, Bax level is increased and Bcl-XL level is reduced, and cleavage of procaspase 3, procaspase 9 and PARP is enhanced. We propose that pericentrosomal localization of TIG3 is a key event that results in microtubule and microfilament redistribution and pericentrosomal organelle clustering and that leads to cancer cell apoptosis.

  2. Programmed cell death for defense against anomaly and tumor formation

    International Nuclear Information System (INIS)

    Kondo, Sohei; Norimura, Toshiyuki; Nomura, Taisei

    1995-01-01

    Cell death after exposure to low-level radiation is often considered evidence that radiation is poisonous, however small the dose. Evidence has been accumulating to support the notion that cell death after low-level exposure to radiation results from activation of suicidal genes open-quote programmed cell death close-quote or open-quote apoptosis close-quote - for the health of the whole body. This paper gives experimental evidence that embryos of fruit flies and mouse fetuses have potent defense mechanisms against teratogenic or tumorigenic injury caused by radiation and carcinogens, which function through programmed cell death

  3. Cardiac Glycoside Glucoevatromonoside Induces Cancer Type-Specific Cell Death

    Directory of Open Access Journals (Sweden)

    Naira F. Z. Schneider

    2018-03-01

    Full Text Available Cardiac glycosides (CGs are natural compounds used traditionally to treat congestive heart diseases. Recent investigations repositioned CGs as potential anticancer agents. To discover novel cytotoxic CG scaffolds, we selected the cardenolide glucoevatromonoside (GEV out of 46 CGs for its low nanomolar anti-lung cancer activity. GEV presented reduced toxicity toward non-cancerous cell types (lung MRC-5 and PBMC and high-affinity binding to the Na+/K+-ATPase α subunit, assessed by computational docking. GEV-induced cell death was caspase-independent, as investigated by a multiparametric approach, and culminates in severe morphological alterations in A549 cells, monitored by transmission electron microscopy, live cell imaging and flow cytometry. This non-canonical cell death was not preceded or accompanied by exacerbation of autophagy. In the presence of GEV, markers of autophagic flux (e.g. LC3I-II conversion were impacted, even in presence of bafilomycin A1. Cell death induction remained unaffected by calpain, cathepsin, parthanatos, or necroptosis inhibitors. Interestingly, GEV triggered caspase-dependent apoptosis in U937 acute myeloid leukemia cells, witnessing cancer-type specific cell death induction. Differential cell cycle modulation by this CG led to a G2/M arrest, cyclin B1 and p53 downregulation in A549, but not in U937 cells. We further extended the anti-cancer potential of GEV to 3D cell culture using clonogenic and spheroid formation assays and validated our findings in vivo by zebrafish xenografts. Altogether, GEV shows an interesting anticancer profile with the ability to exert cytotoxic effects via induction of different cell death modalities.

  4. Mechanisms maintaining enhancement of allografts. I. Demonstration of a specific suppressor cell

    International Nuclear Information System (INIS)

    Hall, B.M.

    1985-01-01

    DA rats treated with hyperimmune anti-PVG serum and grafted with (DA X PVG)F1 heart grafts in which graft survival was prolonged for greater than 75 d were used to examine the cellular mechanisms that maintain the state of specific unresponsiveness found in these animals. The capacity of lymphocytes from these animals to effect or inhibit graft rejection on adoptive transfer to irradiated heart-grafted hosts was tested. Spleen cell populations and the T cell subpopulation separated from spleen cells in vitro failed to restore rejection of PVG heart grafts in irradiated DA recipients but restored third party Lew graft rejection. Whole spleen cells had the capacity to suppress the ability of normal DA LNC to cause graft rejection, but T cells from spleen only delayed the restoration of rejection. LNC and recirculating T cells from rats with enhanced grafts adoptively restored PVG rejection, however. These studies show that the state of specific unresponsiveness that follows the induction of passive enhancement is dependent in part upon active suppression, which is induced or mediated by T lymphocytes. The recirculating pool of lymphocytes in these animals is not depleted of specific alloreactive cells with the capacity to initiate and effect rejection. Thus, these animals responsiveness is not like that found in transplantation tolerance induced in neonatal rats, but is, in part, due to a suppressor response that can inhibit normal alloreactive cells capacity to initiate and effect rejection

  5. Nerve Growth Factor in Cancer Cell Death and Survival

    International Nuclear Information System (INIS)

    Molloy, Niamh H.; Read, Danielle E.; Gorman, Adrienne M.

    2011-01-01

    One of the major challenges for cancer therapeutics is the resistance of many tumor cells to induction of cell death due to pro-survival signaling in the cancer cells. Here we review the growing literature which shows that neurotrophins contribute to pro-survival signaling in many different types of cancer. In particular, nerve growth factor, the archetypal neurotrophin, has been shown to play a role in tumorigenesis over the past decade. Nerve growth factor mediates its effects through its two cognate receptors, TrkA, a receptor tyrosine kinase and p75 NTR , a member of the death receptor superfamily. Depending on the tumor origin, pro-survival signaling can be mediated by TrkA receptors or by p75 NTR . For example, in breast cancer the aberrant expression of nerve growth factor stimulates proliferative signaling through TrkA and pro-survival signaling through p75 NTR . This latter signaling through p75 NTR promotes increased resistance to the induction of cell death by chemotherapeutic treatments. In contrast, in prostate cells the p75 NTR mediates cell death and prevents metastasis. In prostate cancer, expression of this receptor is lost, which contributes to tumor progression by allowing cells to survive, proliferate and metastasize. This review focuses on our current knowledge of neurotrophin signaling in cancer, with a particular emphasis on nerve growth factor regulation of cell death and survival in cancer

  6. Autophagic components contribute to hypersensitive cell death in Arabidopsis

    DEFF Research Database (Denmark)

    Hofius, Daniel; Schultz-Larsen, Torsten; Joensen, Jan

    2009-01-01

    Autophagy has been implicated as a prosurvival mechanism to restrict programmed cell death (PCD) associated with the pathogen-triggered hypersensitive response (HR) during plant innate immunity. This model is based on the observation that HR lesions spread in plants with reduced autophagy gene...... expression. Here, we examined receptor-mediated HR PCD responses in autophagy-deficient Arabidopsis knockout mutants (atg), and show that infection-induced lesions are contained in atg mutants. We also provide evidence that HR cell death initiated via Toll/Interleukin-1 (TIR)-type immune receptors through...... the defense regulator EDS1 is suppressed in atg mutants. Furthermore, we demonstrate that PCD triggered by coiled-coil (CC)-type immune receptors via NDR1 is either autophagy-independent or engages autophagic components with cathepsins and other unidentified cell death mediators. Thus, autophagic cell death...

  7. Mechanisms of Ionizing Radiation-Induced Cell Death in Primary Lung Cells

    Science.gov (United States)

    2013-03-05

    lose their capacity to replicate after a certain number       10 of passages. This finite number was termed the “ Hayflick limit ” and cells...Upstream and downstream of mTOR. Genes & development 18:1926-45 78. Hayflick L. 1965. The Limited in Vitro Lifetime of Human Diploid Cell Strains...can lead to death. During the course of radiotherapy, the use of IR for the treatment of thoracic cancers is limited by IR-induced cell death to the

  8. Non-apoptotic cell death associated with perturbations of macropinocytosis.

    Science.gov (United States)

    Maltese, William A; Overmeyer, Jean H

    2015-01-01

    Although macropinocytosis is widely recognized as a distinct form of fluid-phase endocytosis in antigen-presenting dendritic cells, it also occurs constitutively in many other normal and transformed cell types. Recent studies have established that various genetic or pharmacological manipulations can hyperstimulate macropinocytosis or disrupt normal macropinosome trafficking pathways, leading to accumulation of greatly enlarged cytoplasmic vacuoles. In some cases, this extreme vacuolization is associated with a unique form of non-apoptotic cell death termed "methuosis," from the Greek methuo (to drink to intoxication). It remains unclear whether cell death related to dysfunctional macropinocytosis occurs in normal physiological contexts. However, the finding that some types of cancer cells are particularly vulnerable to this unusual form of cell death has raised the possibility that small molecules capable of altering macropinosome trafficking or function might be useful as therapeutic agents against cancers that are resistant to drugs that work by inducing apoptosis. Herein we review examples of cell death associated with dysfunctional macropinocytosis and summarize what is known about the underlying mechanisms.

  9. Non-apoptotic cell death associated with perturbations of macropinocytosis

    Directory of Open Access Journals (Sweden)

    William A. Maltese

    2015-02-01

    Full Text Available Although macropinocytosis is widely recognized as a distinct form of fluid-phase endocytosis in antigen-presenting dendritic cells, it also occurs constitutively in many other normal and transformed cell types. Recent studies have established that various genetic or pharmacological manipulations can hyperstimulate macropinocytosis or disrupt normal macropinosome trafficking pathways, leading to accumulation of greatly enlarged cytoplasmic vacuoles. In some cases, this extreme vacuolization is associated with a unique form of non-apoptotic cell death termed ‘methuosis’, from the Greek methuo (to drink to intoxication. It remains unclear whether cell death related to dysfunctional macropinocytosis occurs in normal physiological contexts. However, the finding that some types of cancer cells are particularly vulnerable to this unusual form of cell death has raised the possibility that small molecules capable of altering macropinosome trafficking or function might be useful as therapeutic agents against cancers that are resistant to drugs that work by inducing apoptosis. Herein we review examples of cell death associated with dysfunctional macropinocytosis and summarize what is known about the underlying mechanisms.

  10. Stem cell death and survival in heart regeneration and repair.

    Science.gov (United States)

    Abdelwahid, Eltyeb; Kalvelyte, Audrone; Stulpinas, Aurimas; de Carvalho, Katherine Athayde Teixeira; Guarita-Souza, Luiz Cesar; Foldes, Gabor

    2016-03-01

    Cardiovascular diseases are major causes of mortality and morbidity. Cardiomyocyte apoptosis disrupts cardiac function and leads to cardiac decompensation and terminal heart failure. Delineating the regulatory signaling pathways that orchestrate cell survival in the heart has significant therapeutic implications. Cardiac tissue has limited capacity to regenerate and repair. Stem cell therapy is a successful approach for repairing and regenerating ischemic cardiac tissue; however, transplanted cells display very high death percentage, a problem that affects success of tissue regeneration. Stem cells display multipotency or pluripotency and undergo self-renewal, however these events are negatively influenced by upregulation of cell death machinery that induces the significant decrease in survival and differentiation signals upon cardiovascular injury. While efforts to identify cell types and molecular pathways that promote cardiac tissue regeneration have been productive, studies that focus on blocking the extensive cell death after transplantation are limited. The control of cell death includes multiple networks rather than one crucial pathway, which underlies the challenge of identifying the interaction between various cellular and biochemical components. This review is aimed at exploiting the molecular mechanisms by which stem cells resist death signals to develop into mature and healthy cardiac cells. Specifically, we focus on a number of factors that control death and survival of stem cells upon transplantation and ultimately affect cardiac regeneration. We also discuss potential survival enhancing strategies and how they could be meaningful in the design of targeted therapies that improve cardiac function.

  11. Acrolein-induced cell death in PC12 cells: role of mitochondria-mediated oxidative stress.

    Science.gov (United States)

    Luo, Jian; Robinson, J Paul; Shi, Riyi

    2005-12-01

    Oxidative stress has been implicated in acrolein cytotoxicity in various cell types, including mammalian spinal cord tissue. In this study we report that acrolein also decreases PC12 cell viability in a reactive oxygen species (ROS)-dependent manner. Specifically, acrolein-induced cell death, mainly necrosis, is accompanied by the accumulation of cellular ROS. Elevating ROS scavengers can alleviate acrolein-induced cell death. Furthermore, we show that exposure to acrolein leads to mitochondrial dysfunction, denoted by the loss of mitochondrial transmembrane potential, reduction of cellular oxygen consumption, and decrease of ATP level. This raises the possibility that the cellular accumulation of ROS could result from the increased production of ROS in the mitochondria of PC12 cells as a result of exposure to acrolein. The acrolein-induced significant decrease of ATP production in mitochondria may also explain why necrosis, not apoptosis, is the dominant type of cell death. In conclusion, our data suggest that one possible mechanism of acrolein-induced cell death could be through mitochondria as its initial target. The subsequent increase of ROS then inflicts cell death and further worsens mitochondria function. Such mechanism may play an important role in CNS trauma and neurodegenerative diseases.

  12. Novel interactions of the von Hippel-Lindau (pVHL) tumor suppressor with the CDKN1 family of cell cycle inhibitors

    OpenAIRE

    Giovanni Minervini; Raffaele Lopreiato; Raissa Bortolotto; Antonella Falconieri; Geppo Sartori; Silvio C. E. Tosatto

    2017-01-01

    Germline inactivation of the von Hippel-Lindau (VHL) tumor suppressor predisposes patients to develop different highly vascularized cancers. pVHL targets the hypoxia-inducible transcription factor (HIF-1?) for degradation, modulating the activation of various genes involved in hypoxia response. Hypoxia plays a relevant role in regulating cell cycle progression, inducing growth arrest in cells exposed to prolonged oxygen deprivation. However, the exact molecular details driving this transition...

  13. Monocytic and granulocytic myeloid derived suppressor cells differentially regulate spatiotemporal tumour plasticity during metastatic cascade.

    Science.gov (United States)

    Ouzounova, Maria; Lee, Eunmi; Piranlioglu, Raziye; El Andaloussi, Abdeljabar; Kolhe, Ravindra; Demirci, Mehmet F; Marasco, Daniela; Asm, Iskander; Chadli, Ahmed; Hassan, Khaled A; Thangaraju, Muthusamy; Zhou, Gang; Arbab, Ali S; Cowell, John K; Korkaya, Hasan

    2017-04-06

    It is widely accepted that dynamic and reversible tumour cell plasticity is required for metastasis, however, in vivo steps and molecular mechanisms are poorly elucidated. We demonstrate here that monocytic (mMDSC) and granulocytic (gMDSC) subsets of myeloid-derived suppressor cells infiltrate in the primary tumour and distant organs with different time kinetics and regulate spatiotemporal tumour plasticity. Using co-culture experiments and mouse transcriptome analyses in syngeneic mouse models, we provide evidence that tumour-infiltrated mMDSCs facilitate tumour cell dissemination from the primary site by inducing EMT/CSC phenotype. In contrast, pulmonary gMDSC infiltrates support the metastatic growth by reverting EMT/CSC phenotype and promoting tumour cell proliferation. Furthermore, lung-derived gMDSCs isolated from tumour-bearing animals enhance metastatic growth of already disseminated tumour cells. MDSC-induced 'metastatic gene signature' derived from murine syngeneic model predicts poor patient survival in the majority of human solid tumours. Thus spatiotemporal MDSC infiltration may have clinical implications in tumour progression.

  14. Suppressors of DnaAATP imposed overinitiation in Escherichia coli

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Riber, Leise; Cohen, Malene

    2011-01-01

    Chromosome replication in Escherichia coli is limited by the supply of DnaA associated with ATP. Cells deficient in RIDA (Regulatory Inactivation of DnaA) due to a deletion of the hda gene accumulate suppressor mutations (hsm) to counteract the overinitiation caused by an elevated DnaAATP level....... Eight spontaneous hda suppressor mutations were identified by whole-genome sequencing, and three of these were analysed further. Two mutations (hsm-2 and hsm-4) mapped in the dnaA gene and led to a reduced ability to initiate replication from oriC. One mutation (hsm-1) mapped to the seqA promoter...

  15. Activation of Cyclin-Dependent Kinase 5 Is a Consequence of Cell Death

    Directory of Open Access Journals (Sweden)

    Yixia Ye

    2009-01-01

    Full Text Available Cyclin-dependent kinase 5 (Cdk5 is similar to other Cdks but is activated during cell differentiation and cell death rather than cell division. Since activation of Cdk5 has been reported in many situations leading to cell death, we attempted to determine if it was required for any form of cell death. We found that Cdk5 is activated during apoptotic deaths and that the activation can be detected even when the cells continue to secondary necrosis. This activation can occur in the absence of Bim, calpain, or neutral cathepsins. The kinase is typically activated by p25, derived from p35 by calpain-mediated cleavage, but inhibition of calpain does not affect cell death or the activation of Cdk5. Likewise, RNAi-forced suppression of the synthesis of Cdk5 does not affect the incidence or kinetics of cell death. We conclude that Cdk5 is activated as a consequence of metabolic changes that are common to many forms of cell death. Thus its activation suggests processes during cell death that will be interesting or important to understand, but activation of Cdk5 is not necessary for cells to die.

  16. Vacuolar processing enzyme: an executor of plant cell death.

    Science.gov (United States)

    Hara-Nishimura, Ikuko; Hatsugai, Noriyuki; Nakaune, Satoru; Kuroyanagi, Miwa; Nishimura, Mikio

    2005-08-01

    Apoptotic cell death in animals is regulated by cysteine proteinases called caspases. Recently, vacuolar processing enzyme (VPE) was identified as a plant caspase. VPE deficiency prevents cell death during hypersensitive response and cell death of limited cell layers at the early stage of embryogenesis. Because plants do not have macrophages, dying cells must degrade their materials by themselves. VPE plays an essential role in the regulation of the lytic system of plants during the processes of defense and development. VPE is localized in the vacuoles, unlike animal caspases, which are localized in the cytosol. Thus, plants might have evolved a regulated cellular suicide strategy that, unlike animal apoptosis, is mediated by VPE and the vacuoles.

  17. Induction of apoptotic cell death by putrescine

    DEFF Research Database (Denmark)

    Takao, Koichi; Rickhag, Karl Mattias; Hegardt, Cecilia

    2006-01-01

    that overexpression of a metabolically stable ODC in CHO cells induced a massive cell death unless the cells were grown in the presence of the ODC inhibitor alpha-difluoromethylornithine (DFMO). Cells overexpressing wild-type (unstable) ODC, on the other hand, were not dependent on the presence of DFMO...... for their growth. The induction of cell death was correlated with a dramatic increase in cellular putrescine levels. Analysis using flow cytometry revealed perturbed cell cycle kinetics, with a large accumulation of cells with sub-G1 amounts of DNA, which is a typical sign of apoptosis. Another strong indication...... of apoptosis was the finding that one of the key enzymes in the apoptotic process, caspase-3, was induced when DFMO was omitted from the growth medium. Furthermore, inhibition of the caspase activity significantly reduced the recruitment of cells to the sub-G1 fraction. In conclusion, deregulation of polyamine...

  18. Oxidative Stress and Programmed Cell Death in Yeast

    International Nuclear Information System (INIS)

    Farrugia, Gianluca; Balzan, Rena

    2012-01-01

    Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed.

  19. Cell Death Conversion under Hypoxic Condition in Tumor Development and Therapy

    Directory of Open Access Journals (Sweden)

    Yu Qiu

    2015-10-01

    Full Text Available Hypoxia, which is common during tumor progression, plays important roles in tumor biology. Failure in cell death in response to hypoxia contributes to progression and metastasis of tumors. On the one hand, the metabolic and oxidative stress following hypoxia could lead to cell death by triggering signal cascades, like LKB1/AMPK, PI3K/AKT/mTOR, and altering the levels of effective components, such as the Bcl-2 family, Atg and p62. On the other hand, hypoxia-induced autophagy can serve as a mechanism to turn over nutrients, so as to mitigate the adverse condition and then avoid cell death potentially. Due to the effective role of hypoxia, this review focuses on the crosstalk in cell death under hypoxia in tumor progression. Additionally, the illumination of cell death in hypoxia could shed light on the clinical applications of cell death targeted therapy.

  20. Effects of epigallocatechin gallate on ultra-violet-induced cell death in PC12 cells

    International Nuclear Information System (INIS)

    Takahashi, Hideo; Seki, Sakiko; Sakamoto, Naotaka; Nakagawa, Shigeki

    2002-01-01

    We examined the effects of catechin on ultra-violet-induced cell death in PC12 cells. PC12 cells were irradiated by ultra-violet C (254 nm) (UVC). We found that the lactate dehydrogenase (LDH) activities in culture media and lipid peroxide in PC12 cells, which indicate cell death and cell membrane damage, respectively, were increased by UVC irradiation in a time-dependent manner. Cell death was gradually stimulated for 9 hours of cultivation after a UVC irradiation period of 10 or 30 min. Epigallocatechin gallate (EGCG), which is one of the main catechins found in green tea, suppressed the increase in LDH activity in culture medium and also inhibited the formation of lipid peroxide. IκB, a member of the cell death signaling system, was phosphorylated at 1 hour after 10 min of UVC irradiation. Stimulation of phosphorylation of IκB by UVC was suppressed by the addition of EGCG. We concluded that EGCG protects the PC12 cell from cell damage caused by UVC irradiation. (author)

  1. Mitochondrial calcium uniporter silencing potentiates caspase-independent cell death in MDA-MB-231 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Curry, Merril C.; Peters, Amelia A. [School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 (Australia); Kenny, Paraic A. [Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Roberts-Thomson, Sarah J. [School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 (Australia); Monteith, Gregory R., E-mail: gregm@uq.edu.au [School of Pharmacy, The University of Queensland, Brisbane, Queensland 4072 (Australia)

    2013-05-10

    Highlights: •Some clinical breast cancers are associated with MCU overexpression. •MCU silencing did not alter cell death initiated with the Bcl-2 inhibitor ABT-263. •MCU silencing potentiated caspase-independent cell death initiated by ionomycin. •MCU silencing promoted ionomycin-mediated cell death without changes in bulk Ca{sup 2+}. -- Abstract: The mitochondrial calcium uniporter (MCU) transports free ionic Ca{sup 2+} into the mitochondrial matrix. We assessed MCU expression in clinical breast cancer samples using microarray analysis and the consequences of MCU silencing in a breast cancer cell line. Our results indicate that estrogen receptor negative and basal-like breast cancers are characterized by elevated levels of MCU. Silencing of MCU expression in the basal-like MDA-MB-231 breast cancer cell line produced no change in proliferation or cell viability. However, distinct consequences of MCU silencing were seen on cell death pathways. Caspase-dependent cell death initiated by the Bcl-2 inhibitor ABT-263 was not altered by MCU silencing; whereas caspase-independent cell death induced by the calcium ionophore ionomycin was potentiated by MCU silencing. Measurement of cytosolic Ca{sup 2+} levels showed that the promotion of ionomycin-induced cell death by MCU silencing occurs independently of changes in bulk cytosolic Ca{sup 2+} levels. This study demonstrates that MCU overexpression is a feature of some breast cancers and that MCU overexpression may offer a survival advantage against some cell death pathways. MCU inhibitors may be a strategy to increase the effectiveness of therapies that act through the induction of caspase-independent cell death pathways in estrogen receptor negative and basal-like breast cancers.

  2. Mechanisms underlying 3-bromopyruvate-induced cell death in colon cancer.

    Science.gov (United States)

    Sun, Yiming; Liu, Zhe; Zou, Xue; Lan, Yadong; Sun, Xiaojin; Wang, Xiu; Zhao, Surong; Jiang, Chenchen; Liu, Hao

    2015-08-01

    3-Bromopyruvate (3BP) is an energy-depleting drug that inhibits Hexokinase II activity by alkylation during glycolysis, thereby suppressing the production of ATP and inducing cell death. As such, 3BP can potentially serve as an anti-tumorigenic agent. Our previous research showed that 3BP can induce apoptosis via AKT /protein Kinase B signaling in breast cancer cells. Here we found that 3BP can also induce colon cancer cell death by necroptosis and apoptosis at the same time and concentration in the SW480 and HT29 cell lines; in the latter, autophagy was also found to be a mechanism of cell death. In HT29 cells, combined treatment with 3BP and the autophagy inhibitor 3-methyladenine (3-MA) exacerbated cell death, while viability in 3BP-treated cells was enhanced by concomitant treatment with the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone (z-VAD-fmk) and the necroptosis inhibitor necrostatin (Nec)-1. Moreover, 3BP inhibited tumor growth in a SW480 xenograft mouse model. These results indicate that 3BP can suppress tumor growth and induce cell death by multiple mechanisms at the same time and concentration in different types of colon cancer cell by depleting cellular energy stores.

  3. Programmed cell death during quinoa perisperm development.

    Science.gov (United States)

    López-Fernández, María Paula; Maldonado, Sara

    2013-08-01

    At seed maturity, quinoa (Chenopodium quinoa Willd.) perisperm consists of uniform, non-living, thin-walled cells full of starch grains. The objective of the present study was to study quinoa perisperm development and describe the programme of cell death that affects the entire tissue. A number of parameters typically measured during programmed cell death (PCD), such as cellular morphological changes in nuclei and cytoplasm, endoreduplication, DNA fragmentation, and the participation of nucleases and caspase-like proteases in nucleus dismantling, were evaluated; morphological changes in cytoplasm included subcellular aspects related to starch accumulation. This study proved that, following fertilization, the perisperm of quinoa simultaneously accumulates storage reserves and degenerates, both processes mediated by a programme of developmentally controlled cell death. The novel findings regarding perisperm development provide a starting point for further research in the Amaranthaceae genera, such as comparing seeds with and without perisperm, and specifying phylogeny and evolution within this taxon. Wherever possible and appropriate, differences between quinoa perisperm and grass starchy endosperm--a morphologically and functionally similar, although genetically different tissue--were highlighted and discussed.

  4. Maitotoxin-induced liver cell death involving loss of cell ATP following influx of calcium

    International Nuclear Information System (INIS)

    Kutty, R.K.; Singh, Y.; Santostasi, G.; Krishna, G.

    1989-01-01

    Maitotoxin, one of the most potent marine toxins known, produced cell death in cultures of rat hepatocytes with a TD50 of 80 pM at 24 hr. The cell death, as indicated by a dose- and time-dependent leakage of lactate dehydrogenase (LDH), was also associated with the leakage of [14C]adenine nucleotides from hepatocytes prelabeled with [14C]-adenine. The toxic effect of maitotoxin was completely abolished by the omission of calcium from the culture medium. The cell death induced by maitotoxin increased with increasing concentrations of calcium in the medium. Treatment of hepatocytes with low concentrations of the toxin (less than 0.5 ng/ml) resulted in increases in 45Ca influx into the cells. At higher concentrations of maitotoxin (greater than 1ng/ml), the initial increase in 45Ca influx was followed by the release of the 45Ca from the cells into the medium. Since the 45Ca release paralleled the LDH leakage, the release of calcium was due to cell death. The 45Ca influx, [14C]adenine nucleotide leakage, and LDH leakage were effectively inhibited by verapamil, a calcium channel blocker. Maitotoxin also induced a time- and dose-dependent loss of ATP from hepatocytes, which preceded the [14C]adenine nucleotide and LDH leakage. Thus, it appears that the cell death resulting from maitotoxin treatment is caused by the elevated intracellular calcium, which in turn inhibits mitochondrial oxidative phosphorylation causing depletion of cell ATP. Loss of cell ATP may be the causative event in the maitotoxin-induced cell death

  5. The calcimimetic R-568 induces apoptotic cell death in prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Cheng Guangming

    2009-07-01

    Full Text Available Abstract Background Increased serum level of parathyroid hormone (PTH was found in metastatic prostate cancers. Calcimimetic R-568 was reported to reduce PTH expression, to suppress cell proliferation and to induce apoptosis in parathyroid cells. In this study, we investigated the effect of R-568 on cellular survival of prostate cancer cells. Methods Prostate cancer cell lines LNCaP and PC-3 were used in this study. Cellular survival was determined with MTT, trypan blue exclusion and fluorescent Live/Death assays. Western blot assay was utilized to assess apoptotic events induced by R-568 treatment. JC-1 staining was used to evaluate mitochondrial membrane potential. Results In cultured prostate cancer LNCaP and PC-3 cells, R-568 treatment significantly reduced cellular survival in a dose- and time-dependent manner. R-568-induced cell death was an apoptotic event, as evidenced by caspase-3 processing and PARP cleavage, as well as JC-1 color change in mitochondria. Knocking down calcium sensing receptor (CaSR significantly reduced R-568-induced cytotoxicity. Enforced expression of Bcl-xL gene abolished R-568-induced cell death, while loss of Bcl-xL expression led to increased cell death in R-568-treated LNCaP cells,. Conclusion Taken together, our data demonstrated that calcimimetic R-568 triggers an intrinsic mitochondria-related apoptotic pathway, which is dependent on the CaSR and is modulated by Bcl-xL anti-apoptotic pathway.

  6. Nerve Growth Factor in Cancer Cell Death and Survival

    Energy Technology Data Exchange (ETDEWEB)

    Molloy, Niamh H.; Read, Danielle E.; Gorman, Adrienne M., E-mail: adrienne.gorman@nuigalway.ie [Apoptosis Research Centre, School of Natural Sciences, National University of Ireland, Galway (Ireland)

    2011-02-01

    One of the major challenges for cancer therapeutics is the resistance of many tumor cells to induction of cell death due to pro-survival signaling in the cancer cells. Here we review the growing literature which shows that neurotrophins contribute to pro-survival signaling in many different types of cancer. In particular, nerve growth factor, the archetypal neurotrophin, has been shown to play a role in tumorigenesis over the past decade. Nerve growth factor mediates its effects through its two cognate receptors, TrkA, a receptor tyrosine kinase and p75{sup NTR}, a member of the death receptor superfamily. Depending on the tumor origin, pro-survival signaling can be mediated by TrkA receptors or by p75{sup NTR}. For example, in breast cancer the aberrant expression of nerve growth factor stimulates proliferative signaling through TrkA and pro-survival signaling through p75{sup NTR}. This latter signaling through p75{sup NTR} promotes increased resistance to the induction of cell death by chemotherapeutic treatments. In contrast, in prostate cells the p75{sup NTR} mediates cell death and prevents metastasis. In prostate cancer, expression of this receptor is lost, which contributes to tumor progression by allowing cells to survive, proliferate and metastasize. This review focuses on our current knowledge of neurotrophin signaling in cancer, with a particular emphasis on nerve growth factor regulation of cell death and survival in cancer.

  7. Myeloid-Derived Suppressor Cells Specifically Suppress IFN-γ Production and Antitumor Cytotoxic Activity of Vδ2 T Cells

    Directory of Open Access Journals (Sweden)

    Alessandra Sacchi

    2018-06-01

    Full Text Available γδ T cells represent less than 5% of circulating T cells; they exert a potent cytotoxic function against tumor or infected cells and secrete cytokines like conventional αβ T cells. As αβ T cells γδ T cells reside in the typical T cell compartments (the lymph nodes and spleen, but are more widely distributed in tissues throughout the body. For these reasons, some investigators are exploring the possibility of immunotherapies aimed to expand and activate Vδ2 T cells, or using them as Chimeric Antigen Receptor carriers. However, the role of immunosuppressive microenvironment on Vδ2 T cells during infections and cancers has not been completely elucidated. In particular, the effects of myeloid-derived suppressor cells (MDSC, largely expanded in such pathologies, were not explored. In the present work, we demonstrated that MDSC may inhibit IFN-γ production and degranulation of phosphoantigen-activated Vδ2 T cells. Moreover, the Vδ2 T cells cytotoxic activity against the Burkitt lymphoma cell line Daudi and Jurkat cell line were impaired by MDSC. The Arginase I seems to be involved in the impairment of Vδ2 T cell function induced by both tumor cells and MDSC. These data open a key issue in the context of Vδ2-targeted immunoteraphy, suggesting the need of combined strategies aimed to boost Vδ2 T cells circumventing tumor- and MDSC-induced Vδ2 T cells suppression.

  8. The extrinsic cell death pathway and the élan mortel.

    Science.gov (United States)

    Wallach, D; Kang, T-B; Kovalenko, A

    2008-10-01

    Early in the exploration of the chemical nature of life, it was widely believed that the molecules of living organisms, by their very nature, differ from those of inorganic material molecules and possess a vital force ('élan vital'). Similarly, early scientific thinking on the subject of cell death and its induction by cytotoxic cells of the immune system was pervaded by a sense that the molecules mediating these functions possess intrinsic deadly activity and are dedicated exclusively to death-related tasks. This impression was also reflected in the initial notions of the mode of action of intracellular proteins that signal for death. It is now gradually becoming clear, however, that proteins participating in death induction also have functions unrelated to death. Nevertheless, as exemplified by studies of the function of caspase-8 (an enzyme that signals both for activation of the extrinsic cell-death pathway and for non-death-related effects), analysis of the mechanistic basis for such heterogeneity might allow identification of distinct structural determinants in the proteins participating in death induction that do bear death specificity.

  9. Trans-sialidase-based vaccine candidate protects against Trypanosoma cruzi infection, not only inducing an effector immune response but also affecting cells with regulatory/suppressor phenotype

    Science.gov (United States)

    Prochetto, Estefanía; Roldán, Carolina; Bontempi, Iván A.; Bertona, Daiana; Peverengo, Luz; Vicco, Miguel H.; Rodeles, Luz M.; Pérez, Ana R.; Marcipar, Iván S.; Cabrera, Gabriel

    2017-01-01

    Prophylactic and/or therapeutic vaccines have an important potential to control Trypanosoma cruzi (T. cruzi)infection. The involvement of regulatory/suppressor immune cells after an immunization treatment and T. cruzi infection has never been addressed. Here we show that a new trans-sialidase-based immunogen (TSf) was able to confer protection, correlating not only with beneficial changes in effector immune parameters, but also influencing populations of cells related to immune control. Regarding the effector response, mice immunized with TSf showed a TS-specific antibody response, significant delayed-type hypersensitivity (DTH) reactivity and increased production of IFN-γ by CD8+ splenocytes. After a challenge with T. cruzi, TSf-immunized mice showed 90% survival and low parasitemia as compared with 40% survival and high parasitemia in PBS-immunized mice. In relation to the regulatory/suppressor arm of the immune system, after T. cruzi infection TSf-immunized mice showed an increase in spleen CD4+ Foxp3+ regulatory T cells (Treg) as compared to PBS-inoculated and infected mice. Moreover, although T. cruzi infection elicited a notable increase in myeloid derived suppressor cells (MDSC) in the spleen of PBS-inoculated mice, TSf-immunized mice showed a significantly lower increase of MDSC. Results presented herein highlight the need of studying the immune response as a whole when a vaccine candidate is rationally tested. PMID:28938533

  10. A genome-wide shRNA screen identifies GAS1 as a novel melanoma metastasis suppressor gene.

    Science.gov (United States)

    Gobeil, Stephane; Zhu, Xiaochun; Doillon, Charles J; Green, Michael R

    2008-11-01

    Metastasis suppressor genes inhibit one or more steps required for metastasis without affecting primary tumor formation. Due to the complexity of the metastatic process, the development of experimental approaches for identifying genes involved in metastasis prevention has been challenging. Here we describe a genome-wide RNAi screening strategy to identify candidate metastasis suppressor genes. Following expression in weakly metastatic B16-F0 mouse melanoma cells, shRNAs were selected based upon enhanced satellite colony formation in a three-dimensional cell culture system and confirmed in a mouse experimental metastasis assay. Using this approach we discovered 22 genes whose knockdown increased metastasis without affecting primary tumor growth. We focused on one of these genes, Gas1 (Growth arrest-specific 1), because we found that it was substantially down-regulated in highly metastatic B16-F10 melanoma cells, which contributed to the high metastatic potential of this mouse cell line. We further demonstrated that Gas1 has all the expected properties of a melanoma tumor suppressor including: suppression of metastasis in a spontaneous metastasis assay, promotion of apoptosis following dissemination of cells to secondary sites, and frequent down-regulation in human melanoma metastasis-derived cell lines and metastatic tumor samples. Thus, we developed a genome-wide shRNA screening strategy that enables the discovery of new metastasis suppressor genes.

  11. Phytochemical Compositions of Immature Wheat Bran, and Its Antioxidant Capacity, Cell Growth Inhibition, and Apoptosis Induction through Tumor Suppressor Gene

    Directory of Open Access Journals (Sweden)

    Mi Jeong Kim

    2016-09-01

    Full Text Available The purpose of this study was to investigate the phytochemical compositions and antioxidant capacity, cell growth inhibition, and apoptosis induction in extracts of immature wheat bran. Immature wheat bran (IWB was obtained from immature wheat harvested 10 days earlier than mature wheat. The phytochemical compositions of bran extract samples were analyzed by ultra-high performance liquid chromatography. The total ferulic acid (3.09 mg/g and p-coumaric acid (75 µg/g in IWB were significantly higher than in mature wheat bran (MWB, ferulic acid: 1.79 mg/g; p-coumaric acid: 55 µg/g. The oxygen radical absorbance capacity (ORAC: 327 µM Trolox equivalents (TE/g and cellular antioxidant activity (CAA: 4.59 µM Quercetin equivalents (QE/g of the IWB were higher than those of the MWB (ORAC: 281 µM TE/g; CAA: 0.63 µM QE/g. When assessing cell proliferation, the IWB extracts resulted in the lowest EC50 values against HT-29 (18.9 mg/mL, Caco-2 (7.74 mg/mL, and HeLa cells (8.17 mg/mL among bran extract samples. Additionally, the IWB extracts increased the gene expression of p53 and PTEN (tumor suppressor genes in HT-29 cells, indicating inhibited cell growth and induced apoptosis through tumor suppressor genes.

  12. RET is a potential tumor suppressor gene in colorectal cancer

    Science.gov (United States)

    Luo, Yanxin; Tsuchiya, Karen D.; Park, Dong Il; Fausel, Rebecca; Kanngurn, Samornmas; Welcsh, Piri; Dzieciatkowski, Slavomir; Wang, Jianping; Grady, William M.

    2012-01-01

    Cancer arises as the consequence of mutations and epigenetic alterations that activate oncogenes and inactivate tumor suppressor genes. Through a genome-wide screen for methylated genes in colon neoplasms, we identified aberrantly methylated RET in colorectal cancer. RET, a transmembrane receptor tyrosine kinase and a receptor for the GDNF-family ligands, was one of the first oncogenes to be identified and has been shown to be an oncogene in thyroid cancer and pheochromocytoma. However, unexpectedly, we found RET is methylated in 27% of colon adenomas and in 63% of colorectal cancers, and now provide evidence that RET has tumor suppressor activity in colon cancer. The aberrant methylation of RET correlates with decreased RET expression, whereas the restoration of RET in colorectal cancer cell lines results in apoptosis. Furthermore, in support of a tumor suppressor function of RET, mutant RET has also been found in primary colorectal cancer. We now show that these mutations inactivate RET, which is consistent with RET being a tumor suppressor gene in the colon. These findings suggest that the aberrant methylation of RET and the mutational inactivation of RET promote colorectal cancer formation and that RET can serve as a tumor suppressor gene in the colon. Moreover, the increased frequency of methylated RET in colon cancers compared to adenomas suggests RET inactivation is involved in the progression of colon adenomas to cancer. PMID:22751117

  13. Suppressor of fused (Sufu) promotes epithelial-mesenchymal transition (EMT) in cervical squamous cell carcinoma

    Science.gov (United States)

    Zhang, Ziyu; Zou, Yang; Liang, Meirong; Chen, Yuanting; Luo, Yong; Yang, Bicheng; Liu, Faying; Qin, Yunna; He, Deming; Wang, Feng; Huang, Ouping

    2017-01-01

    Suppressor of fused is essential for the maximal activation of Sonic Hedgehog signaling in development and tumorigenesis. However, the role of Sufu in cervical carcinoma remains unknown. Here, we report new findings of Sufu in regulating the epithelial-to-mesenchymal transition through the FoxM1 transcriptional modulation by 14-3-3ζ protein in cervical carcinoma. Sufu is overexpressed in cervical squamous cell carcinoma and its level in clinical tumor tissues is positively correlated with 14-3-3ζ. Functionanlly, siSufu remarkably prevents the cancer cell migration and invasion. We further demonstrate that the transcriptional activity of Sufu is increased by FoxM1, of which stability is promoted by 14-3-3ζ. Knockdown FoxM1 decreases the invasion of SiHa cells and reconstitution of Sufu rescues the invasion of these cells.Finally, overexpression of Sufu is significantly associated with differentiation grade, FIGO stage, Depth of stromal invasion and vascular cancer embolus. Our findings highlight a novel role for Sufu in cervical carcinogenesis. PMID:29371981

  14. Nuclear DAMP complex-mediated RAGE-dependent macrophage cell death

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ruochan [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Department of Infectious Diseases and State Key Lab of Viral Hepatitis, Xiangya Hospital, Central South University, Changsha, Hunan 410008 (China); Fu, Sha; Fan, Xue-Gong [Department of Infectious Diseases and State Key Lab of Viral Hepatitis, Xiangya Hospital, Central South University, Changsha, Hunan 410008 (China); Lotze, Michael T.; Zeh, Herbert J. [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Tang, Daolin, E-mail: tangd2@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Kang, Rui, E-mail: kangr@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213 (United States)

    2015-03-13

    High mobility group box 1 (HMGB1), histone, and DNA are essential nuclear components involved in the regulation of chromosome structure and function. In addition to their nuclear function, these molecules act as damage-associated molecular patterns (DAMPs) alone or together when released extracellularly. The synergistic effect of these nuclear DNA-HMGB1-histone complexes as DAMP complexes (nDCs) on immune cells remains largely unexplored. Here, we demonstrate that nDCs limit survival of macrophages (e.g., RAW264.7 and peritoneal macrophages) but not cancer cells (e.g., HCT116, HepG2 and Hepa1-6). nDCs promote production of inflammatory tumor necrosis factor α (TNFα) release, triggering reactive oxygen species-dependent apoptosis and necrosis. Moreover, the receptor for advanced glycation end products (RAGE), but not toll-like receptor (TLR)-4 and TLR-2, was required for Akt-dependent TNFα release and subsequent cell death following treatment with nDCs. Genetic depletion of RAGE by RNAi, antioxidant N-Acetyl-L-cysteine, and TNFα neutralizing antibody significantly attenuated nDC-induced cell death. These findings provide evidence supporting novel signaling mechanisms linking nDCs and inflammation in macrophage cell death. - Highlights: • Nuclear DAMP complexes (nDCs) selectively induce cell death in macrophages, but not cancer cells. • TNFα-mediated oxidative stress is required for nDC-induced death. • RAGE-mediated Akt activation is required for nDC-induced TNFα release. • Blocking RAGE and TNFα inhibits nDC-induced macrophage cell death.

  15. A High-Throughput Small Molecule Screen for C. elegans Linker Cell Death Inhibitors.

    Directory of Open Access Journals (Sweden)

    Andrew R Schwendeman

    Full Text Available Programmed cell death is a ubiquitous process in metazoan development. Apoptosis, one cell death form, has been studied extensively. However, mutations inactivating key mammalian apoptosis regulators do not block most developmental cell culling, suggesting that other cell death pathways are likely important. Recent work in the nematode Caenorhabditis elegans identified a non-apoptotic cell death form mediating the demise of the male-specific linker cell. This cell death process (LCD, linker cell-type death is morphologically conserved, and its molecular effectors also mediate axon degeneration in mammals and Drosophila. To develop reagents to manipulate LCD, we established a simple high-throughput screening protocol for interrogating the effects of small molecules on C. elegans linker cell death in vivo. From 23,797 compounds assayed, 11 reproducibly block linker cell death onset. Of these, five induce animal lethality, and six promote a reversible developmental delay. These results provide proof-of principle validation of our screening protocol, demonstrate that developmental progression is required for linker cell death, and suggest that larger scale screens may identify LCD-specific small-molecule regulators that target the LCD execution machinery.

  16. Active suppression of host-vs-graft reaction in pregnant mice. VII. Spontaneous abortion of allogeneic CBA/J x DBA/2 fetuses in the uterus of CBA/J mice correlates with deficient non-T suppressor cell activity

    International Nuclear Information System (INIS)

    Clark, D.A.; Chaput, A.; Tutton, D.

    1986-01-01

    The mammalian fetus has been viewed as an unusually successful type of allograft and unexplained spontaneous abortion as a possible example of maternal rejection. Previous studies have shown the presence of small lymphocytic suppressor cells in the murine decidua which block the generation and reactivation of anti-paternal cytotoxic T lymphocytes (CTL) and lymphokine-activated killer cells (LAK) by elaborating a factor that inhibits the response to interleukin 2 (IL 2). A deficiency of these suppressor cells was associated with implants of xenogeneic Mus caroli embryos in the Mus musculus uterus which are infiltrated by maternal lymphoid cells and aborted. A deficiency of such suppressor cells in the lymph nodes draining the uterus of CBA/J females in the process of aborting their semi-allogeneic CBA x DBA/2 F 1 progeny has also been shown. CBA/J females possess significantly lower levels of decidua-associated non-T suppressor cells on day 8.5 to 10.5 of allopregnancy than do mothers that will produce large litters of live babies. The F 1 embryos are infiltrated by maternal lymphocytes prior to abortion, and the infiltration and abortion rate appears to be augmented by pre-immunization with paternal DBA/2 spleen cells. The CBA/J x DBA/2J mating combination provides a model of spontaneous abortion in which immunologic factors play an important role and demonstrates that the association between deficiency of decidua-associated suppressor cells and xenopregnancy failure also holds true for the failure of allopregnancies resulting from natural within-species mating

  17. Sorafenib-induced defective autophagy promotes cell death by necroptosis

    OpenAIRE

    Kharaziha, Pedram; Chioureas, Dimitris; Baltatzis, George; Fonseca, Pedro; Rodriguez, Patricia; Gogvadze, Vladimir; Lennartsson, Lena; Bj?rklund, Ann-Charlotte; Zhivotovsky, Boris; Grand?r, Dan; Egevad, Lars; Nilsson, Sten; Panaretakis, Theocharis

    2015-01-01

    Autophagy is one of the main cytoprotective mechanisms that cancer cells deploy to withstand the cytotoxic stress and survive the lethal damage induced by anti-cancer drugs. However, under specific conditions, autophagy may, directly or indirectly, induce cell death. In our study, treatment of the Atg5-deficient DU145 prostate cancer cells, with the multi-tyrosine kinase inhibitor, sorafenib, induces mitochondrial damage, autophagy and cell death. Molecular inhibition of autophagy by silencin...

  18. Sensory hair cell death and regeneration in fishes

    Directory of Open Access Journals (Sweden)

    Jerry D. Monroe

    2015-04-01

    Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

  19. The effect of age at exposure on the inactivating mechanisms and relative contributions of key tumor suppressor genes in radiation-induced mouse T-cell lymphomas

    Energy Technology Data Exchange (ETDEWEB)

    Sunaoshi, Masaaki [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Department of Biological Sciences, College of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512 (Japan); Amasaki, Yoshiko; Hirano-Sakairi, Shinobu; Blyth, Benjamin J. [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Morioka, Takamitsu [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kaminishi, Mutsumi [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shang, Yi [Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Nishimura, Mayumi; Shimada, Yoshiya [Radiobiology for Children' s Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Tachibana, Akira [Department of Biological Sciences, College of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512 (Japan); and others

    2015-09-15

    Highlights: • T-cell lymphoma incidence, latency and weight did not change with age at exposure. • Lymphomas had frequent loss of heterozygosity on chromosomes 4, 11 and 19. • These lesions targeted the Cdkn2a, Ikaros and Pten tumor suppressor genes. • Age at exposure may influence which tumor suppressor genes are lost in each tumor. • The mechanisms of tumor suppressor gene loss were different at each locus. - Abstract: Children are considered more sensitive to radiation-induced cancer than adults, yet any differences in genomic alterations associated with age-at-exposure and their underlying mechanisms remain unclear. We assessed genome-wide DNA copy number and mutation of key tumor suppressor genes in T-cell lymphomas arising after weekly irradiation of female B6C3F1 mice with 1.2 Gy X-rays for 4 consecutive weeks starting during infancy (1 week old), adolescence (4 weeks old) or as young adults (8 weeks old). Although T-cell lymphoma incidence was similar, loss of heterozygosity at Cdkn2a on chromosome 4 and at Ikaros on chromosome 11 was more frequent in the two older groups, while loss at the Pten locus on chromosome 19 was more frequent in the infant-irradiated group. Cdkn2a and Ikaros mutation/loss was a common feature of the young adult-irradiation group, with Ikaros frequently (50%) incurring multiple independent hits (including deletions and mutations) or suffering a single hit predicted to result in a dominant negative protein (such as those lacking exon 4, an isoform we have designated Ik12, which lacks two DNA binding zinc-finger domains). Conversely, Pten mutations were more frequent after early irradiation (60%) than after young adult-irradiation (30%). Homozygous Pten mutations occurred without DNA copy number change after irradiation starting in infancy, suggesting duplication of the mutated allele by chromosome mis-segregation or mitotic recombination. Our findings demonstrate that while deletions on chromosomes 4 and 11 affecting Cdkn2

  20. Mechanisms of Virus-Induced Neural Cell Death

    National Research Council Canada - National Science Library

    Tyler, Kenneth

    2002-01-01

    Virtually all known neurotropic viruses are capable of killing infected cells by inducing a specific pattern of cell death known as apoptosis, yet the mechanism by which this occurs and its relevance...

  1. Deaths of cancer cells observed after X-Ray irradiation

    International Nuclear Information System (INIS)

    Kuwahara, Yoshikazu; Oikawa, Toshiyuki; Ochiai, Yasushi; Fukumoto, Motoi; Kurihara, Ai; Noma, Naoto; Shimura, Tsutomu; Fukumoto, Manabu; Ohkubo, Yasuhito

    2011-01-01

    Radiation induces cell death by apoptosis, autophagy (autophagic cell death, APCD), necrosis, which are respectively called type I, II, III programmed cell death, senescence, mitotic catastrophe, etc. This paper mainly describes details of authors' studies on APCD of clinically relevant radioresistant (CRR) HepG2-8960-R cells established from proliferating survivor even after repeated X-irradiation of >30 days x 2 Gy/day to the parent HepG2 cells. Autophagy forms autophagosome where many proteins are thoroughly degraded differing from proteasomal ubiquitin system, has been known essentially related to death and survival of injured cells under certain tissue conditions, and is distinguishable from other modes of cell death by morphological and cytochemical means. One of important authors' findings is as follows. APCD of CRR cells is normally seen in 20% and of the parent strain, 5%. When they are X-irradiated at 10 Gy, APCD of the latter is more (70%) than the former (40%), and no APCD is induced by 2 Gy x 5 days in the former in contrast to the latter. APCD by radiation is thus conceivably suppressed in CRR cells, suggesting that their radioresistance can be reversed by treatment to induce APCD. Autophagy is usually suppressed by mammalian target of rapamycin (mTOR), and when CRR cells are treated with rapamycin, they become radiosensitive to the comparable level to the parent HepG2. When HepG2 cells are treated with 3-methyladenine, an inhibitor of autophagy, or Beclin siRNA, they become radioresistant. For effectiveness of APCD induction and suppression on cancer therapy, results are contradictory in certain reports and autophagy should be a problem to be further elucidated from radiation biology aspect. (author)

  2. Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death.

    Science.gov (United States)

    Clark, Amy L; Kanekura, Kohsuke; Lavagnino, Zeno; Spears, Larry D; Abreu, Damien; Mahadevan, Jana; Yagi, Takuya; Semenkovich, Clay F; Piston, David W; Urano, Fumihiko

    2017-07-17

    Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca 2+ -ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.

  3. Blockade of the ERK pathway markedly sensitizes tumor cells to HDAC inhibitor-induced cell death

    International Nuclear Information System (INIS)

    Ozaki, Kei-ichi; Minoda, Ai; Kishikawa, Futaba; Kohno, Michiaki

    2006-01-01

    Constitutive activation of the extracellular signal-regulated kinase (ERK) pathway is associated with the neoplastic phenotype of a large number of human tumor cells. Although specific blockade of the ERK pathway by treating such tumor cells with potent mitogen-activated protein kinase/ERK kinase (MEK) inhibitors completely suppresses their proliferation, it by itself shows only a modest effect on the induction of apoptotic cell death. However, these MEK inhibitors markedly enhance the efficacy of histone deacetylase (HDAC) inhibitors to induce apoptotic cell death: such an enhanced cell death is observed only in tumor cells in which the ERK pathway is constitutively activated. Co-administration of MEK inhibitor markedly sensitizes tumor cells to HDAC inhibitor-induced generation of reactive oxygen species, which appears to mediate the enhanced cell death induced by the combination of these agents. These results suggest that the combination of MEK inhibitors and HDAC inhibitors provides an efficient chemotherapeutic strategy for the treatment of tumor cells in which the ERK pathway is constitutively activated

  4. An approach to the unification of suppressor T cell circuits: a simplified assay for the induction of suppression by T cell-derived, antigen-binding molecules (T-ABM).

    Science.gov (United States)

    Chue, B; Ferguson, T A; Beaman, K D; Rosenman, S J; Cone, R E; Flood, P M; Green, D R

    1989-01-01

    A system is presented in which the in vitro response to sheep red blood cells (SRBC) can be regulated using antigenic determinants coupled to SRBC and T cell-derived antigen-binding molecules (T-ABM) directed against the coupled determinants. T suppressor-inducer factors (TsiF's) are composed of two molecules, one of which is a T-ABM and one which bears I-J determinants (I-J+ molecule). Using two purified T-ABM which have not previously been shown to have in vitro activity, we produced antigen-specific TsiF's which were capable of inducing the suppression of the anti-SRBC response. Suppression was found to require both the T-ABM and the I-J+ molecule, SRBC conjugated with the antigen for which the T-ABM was specific, and a population of Ly-2+ T cells in the culture. Two monoclonal TsiF (or TsF1) were demonstrated to induce suppression of the anti-SRBC response in this system, provided the relevant antigen was coupled to the SRBC in culture. The results are discussed in terms of the general functions of T-ABM in the immune system. This model will be useful in direct, experimental comparisons of the function of T-ABM and suppressor T cell factors under study in different systems and laboratories.

  5. Expansion of monocytic myeloid-derived suppressor cells in endometriosis patients: A pilot study.

    Science.gov (United States)

    Chen, Haiwen; Qin, Shuang; Lei, Aihua; Li, Xing; Gao, Qi; Dong, Jingyin; Xiao, Qing; Zhou, Jie

    2017-06-01

    Endometriosis is a chronic inflammation disease and is closely associated with immune dysregulation. Myeloid-derived suppressor cells (MDSCs) are a negative regulator of the immune system. The aim of this study was to evaluate the possible role of MDSCs in endometriosis patients. We collected the peripheral blood and peritoneal fluid from endometriosis patients and controls and analyzed M-MDSCs level using specific monoclonal antibodies recognizing HLA-DR, CD33, CD11b, CD14 markers by flow cytometry. We found that there existed abnormal expansion of monocytic MDSCs (M-MDSCs) (HLA-DR -/low CD33 + CD11b + CD14 + ) in peripheral blood and peritoneal fluid of patients with endometriosis. Functional studies revealed that M-MDSCs from endometriosis patients significantly suppressed T-cell responses and produced high level of reactive oxygen species (ROS). The elevation of M-MDSCs from endometriosis patients may contribute to the disease progression. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Cell death and autophagy: Cytokines, drugs, and nutritional factors

    International Nuclear Information System (INIS)

    Bursch, Wilfried; Karwan, Anneliese; Mayer, Miriam; Dornetshuber, Julia; Froehwein, Ulrike; Schulte-Hermann, Rolf; Fazi, Barbara; Di Sano, Federica; Piredda, Lucia; Piacentini, Mauro; Petrovski, Goran; Fesues, Laszlo; Gerner, Christopher

    2008-01-01

    Cells may use multiple pathways to commit suicide. In certain contexts, dying cells generate large amounts of autophagic vacuoles and clear large proportions of their cytoplasm, before they finally die, as exemplified by the treatment of human mammary carcinoma cells with the anti-estrogen tamoxifen (TAM, ≤1 μM). Protein analysis during autophagic cell death revealed distinct proteins of the nuclear fraction including GST-π and some proteasomal subunit constituents to be affected during autophagic cell death. Depending on the functional status of caspase-3, MCF-7 cells may switch between autophagic and apoptotic features of cell death [Fazi, B., Bursch, W., Fimia, G.M., Nardacci R., Piacentini, M., Di Sano, F., Piredda, L., 2008. Fenretinide induces autophagic cell death in caspase-defective breast cancer cells. Autophagy 4(4), 435-441]. Furthermore, the self-destruction of MCF-7 cells was found to be completed by phagocytosis of cell residues [Petrovski, G., Zahuczky, G., Katona, K., Vereb, G., Martinet, W., Nemes, Z., Bursch, W., Fesues, L., 2007. Clearance of dying autophagic cells of different origin by professional and non-professional phagocytes. Cell Death Diff. 14 (6), 1117-1128]. Autophagy also constitutes a cell's strategy of defense upon cell damage by eliminating damaged bulk proteins/organelles. This biological condition may be exemplified by the treatment of MCF-7 cells with a necrogenic TAM-dose (10 μM), resulting in the lysis of almost all cells within 24 h. However, a transient (1 h) challenge of MCF-7 cells with the same dose allowed the recovery of cells involving autophagy. Enrichment of chaperones in the insoluble cytoplasmic protein fraction indicated the formation of aggresomes, a potential trigger for autophagy. In a further experimental model HL60 cells were treated with TAM, causing dose-dependent distinct responses: 1-5 μM TAM, autophagy predominant; 7-9 μM, apoptosis predominant; 15 μM, necrosis. These phenomena might be

  7. Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection

    Science.gov (United States)

    Doitsh, Gilad; Galloway, Nicole L. K.; Geng, Xin; Yang, Zhiyuan; Monroe, Kathryn M.; Zepeda, Orlando; Hunt, Peter W.; Hatano, Hiroyu; Sowinski, Stefanie; Muñoz-Arias, Isa; Greene, Warner C.

    2014-01-01

    The pathway causing CD4 T-cell death in HIV-infected hosts remains poorly understood although apoptosis has been proposed as a key mechanism. We now show that caspase-3-mediated apoptosis accounts for the death of only a small fraction of CD4 T cells corresponding to those that are both activated and productively infected. The remaining over 95% of quiescent lymphoid CD4 T cells die by caspase-1-mediated pyroptosis triggered by abortive viral infection. Pyroptosis corresponds to an intensely inflammatory form of programmed cell death in which cytoplasmic contents and pro-inflammatory cytokines, including IL-1β, are released. This death pathway thus links the two signature events in HIV infection--CD4 T-cell depletion and chronic inflammation--and creates a pathogenic vicious cycle in which dying CD4 T cells release inflammatory signals that attract more cells to die. This cycle can be broken by caspase 1 inhibitors shown to be safe in humans, raising the possibility of a new class of `anti-AIDS' therapeutics targeting the host rather than the virus.

  8. A novel cervical cancer suppressor 3 (CCS-3) interacts with the BTB domain of PLZF and inhibits the cell growth by inducing apoptosis.

    Science.gov (United States)

    Rho, Seung Bae; Park, Young Gyo; Park, Kyoungsook; Lee, Seung-Hoon; Lee, Je-Ho

    2006-07-24

    Promyelocytic leukemia zinc finger protein (PLZF) is a sequence-specific, DNA binding, transcriptional repressor differentially expressed during embryogenesis and in adult tissues. PLZF is known to be a negative regulator of cell cycle progression. We used PLZF as bait in a yeast two-hybrid screen with a cDNA library from the human ovary tissue. A novel cervical cancer suppressor 3 (CCS-3) was identified as a PLZF interacting partner. Further characterization revealed the BTB domain as an interacting domain of PLZF. Interaction of CCS-3 with PLZF in mammalian cells was also confirmed by co-immunoprecipitation and in vitro binding assays. It was found that, although CCS-3 shares similar homology with eEF1A, the study determined CCS-3 to be an isoform. CCS-3 was observed to be downregulated in human cervical cell lines as well as in cervical tumors when compared to those from normal tissues. Overexpression of CCS-3 in human cervical cell lines inhibits cell growth by inducing apoptosis and suppressing human cyclin A2 promoter activity. These combined results suggest that the potential tumor suppressor activity of CCS-3 may be mediated by its interaction with PLZF.

  9. Myeloid-derived suppressor cells as a potential therapy for experimental autoimmune myasthenia gravis.

    Science.gov (United States)

    Li, Yan; Tu, Zhidan; Qian, Shiguang; Fung, John J; Markowitz, Sanford D; Kusner, Linda L; Kaminski, Henry J; Lu, Lina; Lin, Feng

    2014-09-01

    We recently demonstrated that hepatic stellate cells induce the differentiation of myeloid-derived suppressor cells (MDSCs) from myeloid progenitors. In this study, we found that adoptive transfer of these MDSCs effectively reversed disease progression in experimental autoimmune myasthenia gravis (EAMG), a T cell-dependent and B cell-mediated model for myasthenia gravis. In addition to ameliorated disease severity, MDSC-treated EAMG mice showed suppressed acetylcholine receptor (AChR)-specific T cell responses, decreased levels of serum anti-AChR IgGs, and reduced complement activation at the neuromuscular junctions. Incubating MDSCs with B cells activated by anti-IgM or anti-CD40 Abs inhibited the proliferation of these in vitro-activated B cells. Administering MDSCs into mice immunized with a T cell-independent Ag inhibited the Ag-specific Ab production in vivo. MDSCs directly inhibit B cells through multiple mechanisms, including PGE2, inducible NO synthase, and arginase. Interestingly, MDSC treatment in EAMG mice does not appear to significantly inhibit their immune response to a nonrelevant Ag, OVA. These results demonstrated that hepatic stellate cell-induced MDSCs concurrently suppress both T and B cell autoimmunity, leading to effective treatment of established EAMG, and that the MDSCs inhibit AChR-specific immune responses at least partially in an Ag-specific manner. These data suggest that MDSCs could be further developed as a novel approach to treating myasthenia gravis and, even more broadly, other diseases in which T and B cells are involved in pathogenesis. Copyright © 2014 by The American Association of Immunologists, Inc.

  10. Transient Receptor Potential Vanilloid 1 Expression Mediates Capsaicin-Induced Cell Death

    Directory of Open Access Journals (Sweden)

    Ricardo Ramírez-Barrantes

    2018-06-01

    Full Text Available The transient receptor potential (TRP ion channel family consists of a broad variety of non-selective cation channels that integrate environmental physicochemical signals for dynamic homeostatic control. Involved in a variety of cellular physiological processes, TRP channels are fundamental to the control of the cell life cycle. TRP channels from the vanilloid (TRPV family have been directly implicated in cell death. TRPV1 is activated by pain-inducing stimuli, including inflammatory endovanilloids and pungent exovanilloids, such as capsaicin (CAP. TRPV1 activation by high doses of CAP (>10 μM leads to necrosis, but also exhibits apoptotic characteristics. However, CAP dose–response studies are lacking in order to determine whether CAP-induced cell death occurs preferentially via necrosis or apoptosis. In addition, it is not known whether cytosolic Ca2+ and mitochondrial dysfunction participates in CAP-induced TRPV1-mediated cell death. By using TRPV1-transfected HeLa cells, we investigated the underlying mechanisms involved in CAP-induced TRPV1-mediated cell death, the dependence of CAP dose, and the participation of mitochondrial dysfunction and cytosolic Ca2+ increase. Together, our results contribute to elucidate the pathophysiological steps that follow after TRPV1 stimulation with CAP. Low concentrations of CAP (1 μM induce cell death by a mechanism involving a TRPV1-mediated rapid and transient intracellular Ca2+ increase that stimulates plasma membrane depolarization, thereby compromising plasma membrane integrity and ultimately leading to cell death. Meanwhile, higher doses of CAP induce cell death via a TRPV1-independent mechanism, involving a slow and persistent intracellular Ca2+ increase that induces mitochondrial dysfunction, plasma membrane depolarization, plasma membrane loss of integrity, and ultimately, cell death.

  11. Methuosis: Nonapoptotic Cell Death Associated with Vacuolization of Macropinosome and Endosome Compartments

    OpenAIRE

    Maltese, William A.; Overmeyer, Jean H.

    2014-01-01

    Apoptosis is the most widely recognized form of physiological programmed cell death. During the past three decades, various nonapoptotic forms of cell death have gained increasing attention, largely because of their potential importance in pathological processes, toxicology, and cancer therapy. A recent addition to the panoply of cell death phenotypes is methuosis. The neologism is derived from the Greek methuo (to drink to intoxication) because the hallmark of this form of cell death is disp...

  12. Therapeutic approaches to preventing cell death in Huntington disease.

    Science.gov (United States)

    Kaplan, Anna; Stockwell, Brent R

    2012-12-01

    Neurodegenerative diseases affect the lives of millions of patients and their families. Due to the complexity of these diseases and our limited understanding of their pathogenesis, the design of therapeutic agents that can effectively treat these diseases has been challenging. Huntington disease (HD) is one of several neurological disorders with few therapeutic options. HD, like numerous other neurodegenerative diseases, involves extensive neuronal cell loss. One potential strategy to combat HD and other neurodegenerative disorders is to intervene in the execution of neuronal cell death. Inhibiting neuronal cell death pathways may slow the development of neurodegeneration. However, discovering small molecule inhibitors of neuronal cell death remains a significant challenge. Here, we review candidate therapeutic targets controlling cell death mechanisms that have been the focus of research in HD, as well as an emerging strategy that has been applied to developing small molecule inhibitors-fragment-based drug discovery (FBDD). FBDD has been successfully used in both industry and academia to identify selective and potent small molecule inhibitors, with a focus on challenging proteins that are not amenable to traditional high-throughput screening approaches. FBDD has been used to generate potent leads, pre-clinical candidates, and has led to the development of an FDA approved drug. This approach can be valuable for identifying modulators of cell-death-regulating proteins; such compounds may prove to be the key to halting the progression of HD and other neurodegenerative disorders. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Cytoprotective dibenzoylmethane derivatives protect cells from oxidative stress-induced necrotic cell death.

    Science.gov (United States)

    Hegedűs, Csaba; Lakatos, Petra; Kiss-Szikszai, Attila; Patonay, Tamás; Gergely, Szabolcs; Gregus, Andrea; Bai, Péter; Haskó, György; Szabó, Éva; Virág, László

    2013-06-01

    Screening of a small in-house library of 1863 compounds identified 29 compounds that protected Jurkat cells from hydrogen peroxide-induced cytotoxicity. From the cytoprotective compounds eleven proved to possess antioxidant activity (ABTS radical scavenger effect) and two were found to inhibit poly(ADP-ribosyl)ation (PARylation), a cytotoxic pathway operating in severely injured cells. Four cytoprotective dibenzoylmethane (DBM) derivatives were investigated in more detail as they did not scavenge hydrogen peroxide nor did they inhibit PARylation. These compounds protected cells from necrotic cell death while caspase activation, a parameter of apoptotic cell death was not affected. Hydrogen peroxide activated extracellular signal regulated kinase (ERK1/2) and p38 MAP kinases but not c-Jun N-terminal kinase (JNK). The cytoprotective DBMs suppressed the activation of Erk1/2 but not that of p38. Cytoprotection was confirmed in another cell type (A549 lung epithelial cells), indicating that the cytoprotective effect is not cell type specific. In conclusion we identified DBM analogs as a novel class of cytoprotective compounds inhibiting ERK1/2 kinase and protecting from necrotic cell death by a mechanism independent of poly(ADP-ribose) polymerase inhibition. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. HAMLET (human alpha-lactalbumin made lethal to tumor cells) triggers autophagic tumor cell death.

    Science.gov (United States)

    Aits, Sonja; Gustafsson, Lotta; Hallgren, Oskar; Brest, Patrick; Gustafsson, Mattias; Trulsson, Maria; Mossberg, Ann-Kristin; Simon, Hans-Uwe; Mograbi, Baharia; Svanborg, Catharina

    2009-03-01

    HAMLET, a complex of partially unfolded alpha-lactalbumin and oleic acid, kills a wide range of tumor cells. Here we propose that HAMLET causes macroautophagy in tumor cells and that this contributes to their death. Cell death was accompanied by mitochondrial damage and a reduction in the level of active mTOR and HAMLET triggered extensive cytoplasmic vacuolization and the formation of double-membrane-enclosed vesicles typical of macroautophagy. In addition, HAMLET caused a change from uniform (LC3-I) to granular (LC3-II) staining in LC3-GFP-transfected cells reflecting LC3 translocation during macroautophagy, and this was blocked by the macroautophagy inhibitor 3-methyladenine. HAMLET also caused accumulation of LC3-II detected by Western blot when lysosomal degradation was inhibited suggesting that HAMLET caused an increase in autophagic flux. To determine if macroautophagy contributed to cell death, we used RNA interference against Beclin-1 and Atg5. Suppression of Beclin-1 and Atg5 improved the survival of HAMLET-treated tumor cells and inhibited the increase in granular LC3-GFP staining. The results show that HAMLET triggers macroautophagy in tumor cells and suggest that macroautophagy contributes to HAMLET-induced tumor cell death.

  15. Zinc as a paracrine effector in pancreatic islet cell death.

    Science.gov (United States)

    Kim, B J; Kim, Y H; Kim, S; Kim, J W; Koh, J Y; Oh, S H; Lee, M K; Kim, K W; Lee, M S

    2000-03-01

    Because of a huge amount of Zn2+ in secretory granules of pancreatic islet beta-cells, Zn2+ released in certain conditions might affect the function or survival of islet cells. We studied potential paracrine effects of endogenous Zn2+ on beta-cell death. Zn2+ induced insulinoma/islet cell death in a dose-dependent manner. Chelation of released endogenous Zn2+ by CaEDTA significantly decreased streptozotocin (STZ)-induced islet cell death in an in vitro culture system simulating in vivo circumstances but not in the conventional culture system. Zn2+ chelation in vivo by continuous CaEDTA infusion significantly decreased the incidence of diabetes after STZ administration. N-(6-methoxy-quinolyl)-para-toluene-sulfonamide staining revealed that Zn2+ was densely deposited in degenerating islet cells 24 h after STZ treatment, which was decreased by CaEDTA infusion. We show here that Zn2+ is not a passive element for insulin storage but an active participant in islet cell death in certain conditions, which in time might contribute to the development of diabetes in aged people.

  16. Active ras triggers death in glioblastoma cells through hyperstimulation of macropinocytosis.

    Science.gov (United States)

    Overmeyer, Jean H; Kaul, Aparna; Johnson, Erin E; Maltese, William A

    2008-06-01

    Expression of activated Ras in glioblastoma cells induces accumulation of large phase-lucent cytoplasmic vacuoles, followed by cell death. This was previously described as autophagic cell death. However, unlike autophagosomes, the Ras-induced vacuoles are not bounded by a double membrane and do not sequester organelles or cytoplasm. Moreover, they are not acidic and do not contain the autophagosomal membrane protein LC3-II. Here we show that the vacuoles are enlarged macropinosomes. They rapidly incorporate extracellular fluid-phase tracers but do not sequester transferrin or the endosomal protein EEA1. Ultimately, the cells expressing activated Ras detach from the substratum and rupture, coincident with the displacement of cytoplasm with huge macropinosome-derived vacuoles. These changes are accompanied by caspase activation, but the broad-spectrum caspase inhibitor carbobenzoxy-Val-Ala-Asp-fluoromethylketone does not prevent cell death. Moreover, the majority of degenerating cells do not exhibit chromatin condensation typical of apoptosis. These observations provide evidence for a necrosis-like form of cell death initiated by dysregulation of macropinocytosis, which we have dubbed "methuosis." An activated form of the Rac1 GTPase induces a similar form of cell death, suggesting that Ras acts through Rac-dependent signaling pathways to hyperstimulate macropinocytosis in glioblastoma. Further study of these signaling pathways may lead to the identification of other chemical and physiologic triggers for this unusual form of cell death.

  17. Effect of bone marrow depletion on prostaglandin E-producing suppressor macrophages in mouse spleen

    International Nuclear Information System (INIS)

    Shibata, Y.; Volkman, A.

    1985-01-01

    The i.p. injection of Corynebacterium parvum (CP) into CBA/J mice effected increases in macrophage colony-forming cells (M-CFC) when spleen cells were cultured with L cell culture filtrate as a source of colony-stimulating factor. Significant increases in phagocytic macrophages (M phi) with Fc receptors for IgG2a and IgG2b immune complexes were additionally noted among the spleen cells in these mice. These M phi effectively inhibited Con A-induced lymphocyte proliferation, probably reflecting a 10-fold increase above normal controls in prostaglandin E to 47 ng/3 X 10(6) spleen cells/ml. To determine whether the suppressor M phi are immediate derivatives of splenic M-CFC, we tried to induce suppressor M phi by the injection of CP into mice depleted of bone marrow M-CFC by the earlier administration of the bone-seeking isotope, 89Sr. This procedure reduced M-CFC in the bone marrow to less than 1% of normal for more than 30 days. Monocytes in the blood fell to 5% of normal by day 10 and were 30% on day 30. Levels of resident peritoneal M phi showed relatively little change in this period. By contrast, splenic M-CFC increased to 20-fold higher than the cold 88Sr controls. CP-induced suppressor M phi activity, however, was sharply reduced in 89Sr marrow-depleted mice on day 10, despite the striking increase in M-CFC. There was a threefold increase in the number of phagocytic M phi binding IgG2a immune complexes, with no significant increase in IgG2b binding M phi. The kinetics of recovery of suppressor M phi activity showed that on days 20, 30, and 50 after 89Sr injection the activities reached 20%, 30%, and 70% of the cold control, respectively, and correlated with the recovery of significant levels of M-CFC in the bone marrow. Taken together, these observations suggest that splenic M-CFC are not an immediate source of PGE-suppressor M phi in vivo

  18. Suppressor T-cell factor(s) display an altered pattern of Igh (immunoglobulin heavy chain locus) genetic restriction when developed in an Igh-congeneic host

    International Nuclear Information System (INIS)

    HayGlass, K.T.; Naides, S.J.; Benacerraf, B.; Sy, M.S.

    1985-01-01

    Suppressor T cell factor(s) (TsF 1 ) inhibit the in vivo priming of azobenzenearsonate-specific cytotoxic T-cell responses. The activity of TsF 1 is restricted by genes linked to Igh-1 allotypic markers. TsF 1 obtained from B6.Igh-1/sup n/ mice was unable to suppress the immune response in B6.Igh-1/sup b/ mice and vice versa. However, TsF 1 prepared from B6.Igh-1/sup n/ T cells parked in an Igh-congeneic B6.Igh-1/sup b/ environment displays an additional restriction specificity of the host. Thus, TsF 1 prepared from these Igh-chimeric mice suppressed immune responses in both B6.Igh-1/sup n/ (donor) and B6.Igh-1/sup b/ (recipient) mice but not in mice of the unrelated strain BALB/c.Igh-1/sup a/. The results indicate that the establishment of the suppressor T-cell repertoire is dependent not only upon the genetic background of the individual T cell but also upon the influence of Igh-linked determinants present when T-cell clones are selected during the response

  19. Differential expression of the klf6 tumor suppressor gene upon cell damaging treatments in cancer cells

    International Nuclear Information System (INIS)

    Gehrau, Ricardo C.; D'Astolfo, Diego S.; Andreoli, Veronica; Bocco, Jose L.; Koritschoner, Nicolas P.

    2011-01-01

    The mammalian Krueppel-like factor 6 (KLF6) is involved in critical roles such as growth-related signal transduction, cell proliferation and differentiation, development, apoptosis and angiogenesis. Also, KLF6 appears to be an emerging key factor during cancer development and progression. Its expression is thoroughly regulated by several cell-damaging stimuli. DNA damaging agents at lethal concentrations induce a p53-independent down-regulation of the klf6 gene. To investigate the impact of external stimuli on human klf6 gene expression, its mRNA level was analyzed using a cancer cell line profiling array system, consisting in an assortment of immobilized cDNAs from multiple cell lines treated with several cell-damaging agents at growth inhibitory concentrations (IC 50 ). Cell-damaging agents affected the klf6 expression in 62% of the cDNA samples, though the expression pattern was not dependent on the cell origin type. Interestingly, significant differences (p 50 concentrations of physical and chemical stimuli in a p53-dependent manner. Most of these agents are frequently used in cancer therapy. Induction of klf6 expression in the absence of functional p53 directly correlates with cell death triggered by these compounds, whereas it is down-regulated in p53+/+ cells. Hence, klf6 expression level could represent a valuable marker for the efficiency of cell death upon cancer treatment.

  20. Long-term treatment of anterior pituitary cells with nitric oxide induces programmed cell death.

    Science.gov (United States)

    Velardez, Miguel Omar; Poliandri, Ariel Hernán; Cabilla, Jimena Paula; Bodo, Cristian Carlos Armando; Machiavelli, Leticia Inés; Duvilanski, Beatriz Haydeé

    2004-04-01

    Nitric oxide (NO) plays a complex role in modulating programmed cell death. It can either protect the cell from apoptotic death or mediate apoptosis, depending on its concentration and the cell type and/or status. In this study, we demonstrate that long-term exposition to NO induces cell death of anterior pituitary cells from Wistar female rats. DETA NONOate (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate, 1 mm], a NO donor that releases NO for an extended period of time, decreased cellular viability and prolactin release from primary cultures of anterior pituitary cells. Morphological studies showed an increase in the number of cells with chromatin condensation and nuclear fragmentation at 24 and 48 h after DETA/NO exposure. DNA internucleosomal fragmentation was also observed at the same time. Reversibility of the NO effect on cellular viability and prolactin release was observed only when the cells were incubated with DETA/NO for less than 6 h. Most apoptotic cells were immunopositive for prolactin, suggesting a high susceptibility of lactotrophs to the effect of NO. The cytotoxic effect of NO is dependent of caspase-9 and caspase-3, but seems to be independent of oxidative stress or nitrosative stress. Our results show that the exposition of anterior pituitary cells to NO for long periods induces programmed cell death of anterior pituitary cells.

  1. Aerosol-delivered programmed cell death 4 enhanced apoptosis, controlled cell cycle and suppressed AP-1 activity in the lungs of AP-1 luciferase reporter mice.

    Science.gov (United States)

    Hwang, S-K; Jin, H; Kwon, J T; Chang, S-H; Kim, T H; Cho, C-S; Lee, K H; Young, M R; Colburn, N H; Beck, G R; Yang, H-S; Cho, M-H

    2007-09-01

    The long-term survival of lung cancer patients treated with conventional therapies remains poor and therefore the need for novel approaches remains high. This has led to the re-emergence of aerosol delivery as a therapeutic intervention. In this study, glucosylated polyethylenimine (GPEI) was used as carrier to investigate programmed cell death 4 (PDCD4) and PDCD4 mutant (D418A), an eIF4A-binding mutant, on PDCD4-related signaling and activator protein-1 (AP-1) activity in the lungs of AP-1 luciferase reporter mice. After confirming the efficiency of GPEI as a carrier in lungs, the effects of aerosol-delivered PDCD4 were investigated in AP-1 luciferase reporter mice. Aerosol delivery of GPEI/PDCD4 through a nose-only inhalation facilitated the apoptosis of lungs whereas aerosol PDCD4 mutant did not. Also, such aerosol delivery regulated proteins relevant to cell-cycle control and suppressed AP-1 activity. Results obtained by western blot analysis, immunohistochemistry, luciferase assay and deoxynucleotidyl-transferase-mediated nick end labeling study suggest that combined actions such as facilitating apoptosis, controlling cell cycle and suppression of AP-1 activity by PDCD4 may provide useful tool for designing lung tumor prevention and treatment by which PDCD4 functions as a transformation suppressor in the future.

  2. Cell-Centric View of Apoptosis and Apoptotic Cell Death-Inducing Antitumoral Strategies

    Directory of Open Access Journals (Sweden)

    Maria Dolores Boyano

    2011-03-01

    Full Text Available Programmed cell death and especially apoptotic cell death, occurs under physiological conditions and is also desirable under pathological circumstances. However, the more we learn about cellular signaling cascades, the less plausible it becomes to find restricted and well-limited signaling pathways. In this context, an extensive description of pathway-connections is necessary in order to point out the main regulatory molecules as well as to select the most appropriate therapeutic targets. On the other hand, irregularities in programmed cell death pathways often lead to tumor development and cancer-related mortality is projected to continue increasing despite the effort to develop more active and selective antitumoral compounds. In fact, tumor cell plasticity represents a major challenge in chemotherapy and improvement on anticancer therapies seems to rely on appropriate drug combinations. An overview of the current status regarding apoptotic pathways as well as available chemotherapeutic compounds provides a new perspective of possible future anticancer strategies.

  3. Modulating cell-to-cell variability and sensitivity to death ligands by co-drugging

    International Nuclear Information System (INIS)

    Flusberg, Deborah A; Sorger, Peter K

    2013-01-01

    TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) holds promise as an anti-cancer therapeutic but efficiently induces apoptosis in only a subset of tumor cell lines. Moreover, even in clonal populations of responsive lines, only a fraction of cells dies in response to TRAIL and individual cells exhibit cell-to-cell variability in the timing of cell death. Fractional killing in these cell populations appears to arise not from genetic differences among cells but rather from differences in gene expression states, fluctuations in protein levels and the extent to which TRAIL-induced death or survival pathways become activated. In this study, we ask how cell-to-cell variability manifests in cell types with different sensitivities to TRAIL, as well as how it changes when cells are exposed to combinations of drugs. We show that individual cells that survive treatment with TRAIL can regenerate the sensitivity and death-time distribution of the parental population, demonstrating that fractional killing is a stable property of cell populations. We also show that cell-to-cell variability in the timing and probability of apoptosis in response to treatment can be tuned using combinations of drugs that together increase apoptotic sensitivity compared to treatment with one drug alone. In the case of TRAIL, modulation of cell-to-cell variability by co-drugging appears to involve a reduction in the threshold for mitochondrial outer membrane permeabilization. (paper)

  4. Lipid raft involvement in yeast cell growth and death

    Energy Technology Data Exchange (ETDEWEB)

    Mollinedo, Faustino, E-mail: fmollin@usal.es [Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas - Universidad de Salamanca, Salamanca (Spain)

    2012-10-10

    The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na{sup +}, K{sup +}, and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  5. Lipid raft involvement in yeast cell growth and death

    International Nuclear Information System (INIS)

    Mollinedo, Faustino

    2012-01-01

    The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na + , K + , and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  6. Sodium nitroprusside induces autophagic cell death in glutathione-depleted osteoblasts.

    Science.gov (United States)

    Son, Min Jeong; Lee, Seong-Beom; Byun, Yu Jeong; Lee, Hwa Ok; Kim, Ho-Shik; Kwon, Oh-Joo; Jeong, Seong-Whan

    2010-01-01

    Previous studies reported that high levels of nitric oxide (NO) induce apoptotic cell death in osteoblasts. We examined molecular mechanisms of cytotoxic injury induced by sodium nitroprusside (SNP), a NO donor, in both glutathione (GSH)-depleted and control U2-OS osteoblasts. Cell viability was reduced by much lower effective concentrations of SNP in GSH-depleted cells compared to normal cells. The data suggest that the level of intracellular GSH is critical in SNP-induced cell death processes of osteoblasts. The level of oxidative stress due to SNP treatments doubled in GSH-depleted cells when measured with fluorochrome H2DCFDA. Pretreatment with the NO scavenger PTIO preserved the viability of cells treated with SNP. Viability of cells treated with SNP was recovered by pretreatment with Wortmannin, an autophagy inhibitor, but not by pretreatment with zVAD-fmk, a pan-specific caspase inhibitor. Large increases of LC3-II were shown by immunoblot analysis of the SNP-treated cells, and the increase was blocked by pretreatment with PTIO or Wortmannin; this implies that under GSH-depleted conditions SNP induces different molecular signaling that lead to autophagic cell death. The ultrastructural morphology of SNP-treated cells in transmission electron microscopy showed numerous autophagic vacuoles. These data suggest NO produces oxidative stress and cellular damage that culminate in autophagic cell death of GSH-depleted osteoblasts. Copyright 2010 Wiley Periodicals, Inc.

  7. Apoptosis and tumor cell death in response to HAMLET (human alpha-lactalbumin made lethal to tumor cells).

    Science.gov (United States)

    Hallgren, Oskar; Aits, Sonja; Brest, Patrick; Gustafsson, Lotta; Mossberg, Ann-Kristin; Wullt, Björn; Svanborg, Catharina

    2008-01-01

    HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a molecular complex derived from human milk that kills tumor cells by a process resembling programmed cell death. The complex consists of partially unfolded alpha-lactalbumin and oleic acid, and both the protein and the fatty acid are required for cell death. HAMLET has broad antitumor activity in vitro, and its therapeutic effect has been confirmed in vivo in a human glioblastoma rat xenograft model, in patients with skin papillomas and in patients with bladder cancer. The mechanisms of tumor cell death remain unclear, however. Immediately after the encounter with tumor cells, HAMLET invades the cells and causes mitochondrial membrane depolarization, cytochrome c release, phosphatidyl serine exposure, and a low caspase response. A fraction of the cells undergoes morphological changes characteristic of apoptosis, but caspase inhibition does not rescue the cells and Bcl-2 overexpression or altered p53 status does not influence the sensitivity of tumor cells to HAMLET. HAMLET also creates a state of unfolded protein overload and activates 20S proteasomes, which contributes to cell death. In parallel, HAMLET translocates to tumor cell nuclei, where high-affinity interactions with histones cause chromatin disruption, loss of transcription, and nuclear condensation. The dying cells also show morphological changes compatible with macroautophagy, and recent studies indicate that macroautophagy is involved in the cell death response to HAMLET. The results suggest that HAMLET, like a hydra with many heads, may interact with several crucial cellular organelles, thereby activating several forms of cell death, in parallel. This complexity might underlie the rapid death response of tumor cells and the broad antitumor activity of HAMLET.

  8. Up-regulation of Kir2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    International Nuclear Information System (INIS)

    Kito, Hiroaki; Yamazaki, Daiju; Ohya, Susumu; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

    2011-01-01

    Highlights: → We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. → The ER stress facilitated the expression of inward rectifier K + channel (K ir 2.1) and induced sustained membrane hyperpolarization. → The membrane hyperpolarization induced sustained Ca 2+ entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. → The K ir 2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K + channel (K ir 2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K ir channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca 2+ concentration due to Ca 2+ influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K ir 2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  9. BID links ferroptosis to mitochondrial cell death pathways

    NARCIS (Netherlands)

    Neitemeier, Sandra; Jelinek, Anja; Laino, Vincenzo; Hoffmann, Lena; Eisenbach, Ina; Eying, Roman; Ganjam, Goutham K; Dolga, Amalia M; Oppermann, Sina; Culmsee, Carsten

    2017-01-01

    Ferroptosis has been defined as an oxidative and iron-dependent pathway of regulated cell death that is distinct from caspase-dependent apoptosis and established pathways of death receptor-mediated regulated necrosis. While emerging evidence linked features of ferroptosis induced e.g. by

  10. Downregulation of tumor suppressor QKI in gastric cancer and its implication in cancer prognosis

    International Nuclear Information System (INIS)

    Bian, Yongqian; Wang, Li; Lu, Huanyu; Yang, Guodong; Zhang, Zhang; Fu, Haiyan; Lu, Xiaozhao; Wei, Mengying; Sun, Jianyong; Zhao, Qingchuan; Dong, Guanglong; Lu, Zifan

    2012-01-01

    Highlights: ► QKI expression is decreased in gastric cancer samples. ► Promoter hyper methylation contributes to the downregulation of QKI. ► QKI inhibits the growth of gastric cancer cells. ► Decreased QKI expression predicts poor survival. -- Abstract: Gastric cancer (GC) is the fourth most common cancer and second leading cause of cancer-related death worldwide. RNA-binding protein Quaking (QKI) is a newly identified tumor suppressor in multiple cancers, while its role in GC is largely unknown. Our study here aimed to clarify the relationship between QKI expression with the clinicopathologic characteristics and the prognosis of GC. In the 222 GC patients’ specimens, QKI expression was found to be significantly decreased in most of the GC tissues, which was largely due to promoter hypermethylation. QKI overexpression reduced the proliferation ability of GC cell line in vitro study. In addition, the reduced QKI expression correlated well with poor differentiation status, depth of invasion, gastric lymph node metastasis, distant metastasis, advanced TNM stage, and poor survival. Multivariate analysis showed QKI expression was an independent prognostic factor for patient survival.

  11. THE PROGRAMED CELL DEATH REGULATORS OF ISOLATED MODEL SYSTEMS

    Directory of Open Access Journals (Sweden)

    D. V. Vatlitsov

    2016-06-01

    Full Text Available The technology evolution creates the prerequisites for the emergence of new informational concept and approaches to the formation of a fundamentally new principles of biological objects understanding. The aim was to study the activators of the programmed cell death in an isolated system model. Cell culture aging parameters were performed on flow cytometer. It had formed the theory that the changes in the concentrations of metal ions and increase their extracellular concentration had formed a negative gradient into the cells.regulation of cell death. It was shown that the metals ions concentrations.

  12. The APC tumor suppressor is required for epithelial cell polarization and three-dimensional morphogenesis

    Science.gov (United States)

    Lesko, Alyssa C.; Goss, Kathleen H.; Yang, Frank F.; Schwertner, Adam; Hulur, Imge; Onel, Kenan; Prosperi, Jenifer R.

    2015-01-01

    The Adenomatous Polyposis Coli (APC) tumor suppressor has been previously implicated in the control of apical-basal polarity; yet, the consequence of APC loss-of-function in epithelial polarization and morphogenesis has not been characterized. To test the hypothesis that APC is required for the establishment of normal epithelial polarity and morphogenesis programs, we generated APC-knockdown epithelial cell lines. APC depletion resulted in loss of polarity and multi-layering on permeable supports, and enlarged, filled spheroids with disrupted polarity in 3D culture. Importantly, these effects of APC knockdown were independent of Wnt/β-catenin signaling, but were rescued with either full-length or a carboxy (c)-terminal segment of APC. Moreover, we identified a gene expression signature associated with APC knockdown that points to several candidates known to regulate cell-cell and cell-matrix communication. Analysis of epithelial tissues from mice and humans carrying heterozygous APC mutations further support the importance of APC as a regulator of epithelial behavior and tissue architecture. These data also suggest that the initiation of epithelial-derived tumors as a result of APC mutation or gene silencing may be driven by loss of polarity and dysmorphogenesis. PMID:25578398

  13. Human xenospecific T suppressor cells inhibit T helper cell proliferation to porcine aortic endothelial cells, and NF-kappaB activity in porcine APC.

    Science.gov (United States)

    Ciubotariu, R; Li, J; Colovai, A I; Platt, J L; Cortesini, R; Suciu Foca Cortesini, N

    2001-05-01

    Human T suppressor cells (Ts), capable of preventing autologous T helper cells (Th) from reacting against xenogeneic pig endothelial cells and pig APC can be generated in vitro. Ts derive from a population of CD3(+)CD8(+)CD28(-) T lymphocytes and specifically recognize the MHC class I antigens of the APC used for in vitro immunization. To study the mechanism that underlies suppression, we investigated whether Ts inhibit the expression of costimulatory molecules in xenogeneic professional and semiprofessional APC. We found that Ts down-regulate Th-induced expression of CD86 in pig APC, and that this effect occurs at the level of transcription, as indicated by nuclear run-on and Northern blot assays. EMSA results revealed that inhibition of CD86 expression is mediated by inactivation of transcription factor NF-kappaB. Furthermore, transfection of pig APC with a vector expressing NF-kappaB p65 partially rescued Th-induced expression of the CD86 molecule. These results strongly support the concept that xenospecific Ts inhibit the APC function of xenogeneic cells by preventing activation of NF-kappaB.

  14. HOIP Deficiency Causes Embryonic Lethality by Aberrant TNFR1-Mediated Endothelial Cell Death

    Directory of Open Access Journals (Sweden)

    Nieves Peltzer

    2014-10-01

    Full Text Available Summary: Linear ubiquitination is crucial for innate and adaptive immunity. The linear ubiquitin chain assembly complex (LUBAC, consisting of HOIL-1, HOIP, and SHARPIN, is the only known ubiquitin ligase that generates linear ubiquitin linkages. HOIP is the catalytically active LUBAC component. Here, we show that both constitutive and Tie2-Cre-driven HOIP deletion lead to aberrant endothelial cell death, resulting in defective vascularization and embryonic lethality at midgestation. Ablation of tumor necrosis factor receptor 1 (TNFR1 prevents cell death, vascularization defects, and death at midgestation. HOIP-deficient cells are more sensitive to death induction by both tumor necrosis factor (TNF and lymphotoxin-α (LT-α, and aberrant complex-II formation is responsible for sensitization to TNFR1-mediated cell death in the absence of HOIP. Finally, we show that HOIP’s catalytic activity is necessary for preventing TNF-induced cell death. Hence, LUBAC and its linear-ubiquitin-forming activity are required for maintaining vascular integrity during embryogenesis by preventing TNFR1-mediated endothelial cell death. : HOIP is the main catalytic subunit of the linear ubiquitin chain assembly complex (LUBAC, a crucial regulator of TNF and other immune signaling pathways. Peltzer et al. find that HOIP deficiency results in embryonic lethality at midgestation due to endothelial cell death mediated by TNFR1. Aberrant formation of a TNF-mediated cell-death-inducing complex in HOIP-deficient (but not -proficient cells underlies the phenotype, with the catalytic activity of HOIP required for the control of cell death in response to TNF.

  15. Effect of recombinant adenovirus encoding human p53 tumor suppressor gene combined with radiation therapy on human lymphoma cells lines

    International Nuclear Information System (INIS)

    Yu Zeyang; Fan Wo; Li Dongqing; Zhu Ran; Wan Jianmei; Wang Yongqing; Wu Jinchang

    2008-01-01

    This paper analyzes the inhibitory effect and radiation sensitization of recombinant adenovirus encoding human p53 tumor suppressor gene (rAd-p53) on human lymphoma cell lines. Human lymphoma cell lines were treated with rAd-p53, radiation therapy and combined treatment, respectively. The cell growth inhibition was assessed by MTF. The cell cycle and apoptosis were detected by flow cytometry, and the p53 protein expression was detected by Western blotting. The results showed that extrinsic p53 gene have expressed to some degree, but not at high level. The role of inhibition and radiation sensitivity of rAd-p53 was not significant to human lymphoma cell lines. (authors)

  16. Role of non-canonical Beclin 1-independent autophagy in cell death induced by resveratrol in human breast cancer cells.

    Science.gov (United States)

    Scarlatti, F; Maffei, R; Beau, I; Codogno, P; Ghidoni, R

    2008-08-01

    Resveratrol, a polyphenol found in grapes and other fruit and vegetables, is a powerful chemopreventive and chemotherapeutic molecule potentially of interest for the treatment of breast cancer. The human breast cancer cell line MCF-7, which is devoid of caspase-3 activity, is refractory to apoptotic cell death after incubation with resveratrol. Here we show that resveratrol arrests cell proliferation, triggers death and decreases the number of colonies of cells that are sensitive to caspase-3-dependent apoptosis (MCF-7 casp-3) and also those that are unresponsive to it (MCF-7vc). We demonstrate that resveratrol (i) acts via multiple pathways to trigger cell death, (ii) induces caspase-dependent and caspase-independent cell death in MCF-7 casp-3 cells, (iii) induces only caspase-independent cell death in MCF-7vc cells and (iv) stimulates macroautophagy. Using BECN1 and hVPS34 (human vacuolar protein sorting 34) small interfering RNAs, we demonstrate that resveratrol activates Beclin 1-independent autophagy in both cell lines, whereas cell death via this uncommon form of autophagy occurs only in MCF-7vc cells. We also show that this variant form of autophagic cell death is blocked by the expression of caspase-3, but not by its enzymatic activity. In conclusion, this study reveals that non-canonical autophagy induced by resveratrol can act as a caspase-independent cell death mechanism in breast cancer cells.

  17. Ganglioside GD2 in reception and transduction of cell death signal in tumor cells

    International Nuclear Information System (INIS)

    Doronin, Igor I; Vishnyakova, Polina A; Kholodenko, Irina V; Ponomarev, Eugene D; Ryazantsev, Dmitry Y; Molotkovskaya, Irina M; Kholodenko, Roman V

    2014-01-01

    Ganglioside GD2 is expressed on plasma membranes of various types of malignant cells. One of the most promising approaches for cancer immunotherapy is the treatment with monoclonal antibodies recognizing tumor-associated markers such as ganglioside GD2. It is considered that major mechanisms of anticancer activity of anti-GD2 antibodies are complement-dependent cytotoxicity and/or antibody-mediated cellular cytotoxicity. At the same time, several studies suggested that anti-GD2 antibodies are capable of direct induction of cell death of number of tumor cell lines, but it has not been investigated in details. In this study we investigated the functional role of ganglioside GD2 in the induction of cell death of multiple tumor cell lines by using GD2-specific monoclonal antibodies. Expression of GD2 on different tumor cell lines was analyzed by flow cytometry using anti-GD2 antibodies. By using HPTLC followed by densitometric analysis we measured the amount of ganglioside GD2 in total ganglioside fractions isolated from tumor cell lines. An MTT assay was performed to assess viability of GD2-positive and -negative tumor cell lines treated with anti-GD2 mAbs. Cross-reactivity of anti-GD2 mAbs with other gangliosides or other surface molecules was investigated by ELISA and flow cytometry. Inhibition of GD2 expression was achieved by using of inhibitor for ganglioside synthesis PDMP and/or siRNA for GM2/GD2 and GD3 synthases. Anti-GD2 mAbs effectively induced non-classical cell death that combined features of both apoptosis and necrosis in GD2-positive tumor cells and did not affect GD2-negative tumors. Anti-GD2 mAbs directly induced cell death, which included alteration of mitochondrial membrane potential, induction of apoptotic volume decrease and cell membrane permeability. This cytotoxic effect was mediated exclusively by specific binding of anti-GD2 antibodies with ganglioside GD2 but not with other molecules. Moreover, the level of GD2 expression correlated with

  18. Akebia saponin PA induces autophagic and apoptotic cell death in AGS human gastric cancer cells.

    Science.gov (United States)

    Xu, Mei-Ying; Lee, Dong Hwa; Joo, Eun Ji; Son, Kun Ho; Kim, Yeong Shik

    2013-09-01

    In this study, we investigated the anticancer mechanism of akebia saponin PA (AS), a natural product isolated from Dipsacus asperoides in human gastric cancer cell lines. It was shown that AS-induced cell death is caused by autophagy and apoptosis in AGS cells. The apoptosis-inducing effect of AS was characterized by annexin V/propidium (PI) staining, increase of sub-G1 phase and caspase-3 activation, while the autophagy-inducing effect was indicated by the formation of cytoplasmic vacuoles and microtubule-associated protein 1 light chain-3 II (LC3-II) conversion. The autophagy inhibitor bafilomycin A1 (BaF1) decreased AS-induced cell death and caspase-3 activation, but caspase-3 inhibitor Ac-DEVD-CHO did not affect LC3-II accumulation or AS-induced cell viability, suggesting that AS induces autophagic cell death and autophagy contributes to caspase-3-dependent apoptosis. Furthermore, AS activated p38/c-Jun N-terminal kinase (JNK), which could be inhibited by BaF1, and caspase-3 activation was attenuated by both SB202190 and SP600125, indicating that AS-induced autophagy promotes mitogen-activated protein kinases (MAPKs)-mediated apoptosis. Taken together, these results demonstrate that AS induces autophagic and apoptotic cell death and autophagy plays the main role in akebia saponin PA-induced cell death. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Zebrafish hair cell mechanics and physiology through the lens of noise-induced hair cell death

    Science.gov (United States)

    Coffin, Allison B.; Xu, Jie; Uribe, Phillip M.

    2018-05-01

    Hair cells are exquisitely sensitive to auditory stimuli, but also to damage from a variety of sources including noise trauma and ototoxic drugs. Mammals cannot regenerate cochlear hair cells, while non-mammalian vertebrates exhibit robust regenerative capacity. Our research group uses the lateral line system of larval zebrafish to explore the mechanisms underlying hair cell damage, identify protective therapies, and determine molecular drivers of innate regeneration. The lateral line system contains externally located sensory organs called neuromasts, each composed of ˜8-20 hair cells. Lateral line hair cells are homologous to vertebrate inner ear hair cells and share similar susceptibility to ototoxic damage. In the last decade, the lateral line has emerged as a powerful model system for understanding hair cell death mechanisms and for identifying novel protective compounds. Here we demonstrate that the lateral line is a tractable model for noise-induced hair cell death. We have developed a novel noise damage system capable of inducing over 50% loss of lateral line hair cells, with hair cell death occurring in a dose- and time-dependent manner. Cell death is greatest 72 hours post-exposure. However, early signs of hair cell damage, including changes in membrane integrity and reduced mechanotransduction, are apparent within hours of noise exposure. These features, early signs of damage followed by delayed hair cell death, are consistent with mammalian data, suggesting that noise acts similarly on zebrafish and mammalian hair cells. In our future work we will use our new model system to investigate noise damage events in real time, and to develop protective therapies for future translational research.

  20. Protective Effects of Mouse Bone Marrow Mesenchymal Stem Cell Soup on Staurosporine Induced Cell Death in PC12 and U87 Cell Lines

    Directory of Open Access Journals (Sweden)

    Hossein Zhaleh

    2016-11-01

    Full Text Available Mouse bone marrow mesenchymal stem cells (mBMSCs soup is promising tool for the treatment of neurodegenerative diseases. mBMSCs soup is easily obtained and is capable of transplantation without rejection. We investigated the effects of mBMSC soup on staurosporine-induced cell death in PC12 and U87 cells lines. The percentage of cell viability, cell death, NO concentration, total neurite length (TNL and fraction of cell differentiation (f% were assessed. Viability assay showed that mBM soup (24 and 48h in time dependent were increased cell viability (p<0.05 and also cell death assay showed that cell death in time dependent were decreased, respectively (p<0.05. TNL and fraction of cell differentiation significantly were increased compared with treatment1 (p<0.05. Our data showed that mBM Soup protects cells, increases cell viability, suppresses cell death and improvement the neurite elongation. We concluded that Mouse bone marrow mesenchymal stem cell soup plays an important protective role in staurosporine-induced cell death in PC12 and U87 cell lines.

  1. Involvement of ethylene and lipid signalling in cadmium-induced programmed cell death in tomato suspension cells

    NARCIS (Netherlands)

    Yakimova, E.T.; Kapchina-Toteva, V.M.; Laarhoven, L.J.J.; Harren, F.J.M.; Woltering, E.J.

    2006-01-01

    Cadmium-induced cell death was studied in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells (line MsK8) treated with CdSO4. Within 24 h, cadmium treatment induced cell death in a concentration-dependent manner. Cell cultures showed recovery after 23 days which indicates the existence

  2. LEPREL1 Expression in Human Hepatocellular Carcinoma and Its Suppressor Role on Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Jianguo Wang

    2013-01-01

    Full Text Available Background. Hepatocellular carcinoma (HCC is one of the most aggressive malignancies worldwide. It is characterized by its high invasive and metastatic potential. Leprecan-like 1 (LEPREL1 has been demonstrated to be downregulated in the HCC tissues in previous proteomics studies. The present study is aimed at a new understanding of LEPREL1 function in HCC. Methods. Quantitative RT-PCR, immunohistochemical analysis, and western blot analysis were used to evaluate the expression of LEPREL1 between the paired HCC tumor and nontumorous tissues. The biology function of LEPREL1 was investigated by Cell Counting Kit-8 (CCK8 assay and colony formation assay in HepG2 and Bel-7402 cells. Results. The levels of LEPREL1 mRNA and protein were significantly lower in the HCC tissues as compared to those of the nontumorous tissues. Reduced LEPREL1 expression was not associated with conventional clinical parameters of HCC. Overexpression of LEPREL1 in HepG2 and Bel-7402 cells inhibited cell proliferation (P<0.01 and colony formation (P<0.05. LEPREL1 suppressed tumor cell proliferation through regulation of the cell cycle by downregulation of cyclins. Conclusions. Clinical parameters analysis suggested that LEPREL1 was an independent factor in the development of HCC. The biology function experiments showed that LEPREL1 might serve as a potential tumor suppressor gene by inhibiting the HCC cell proliferation.

  3. Streptococcus sanguinis induces foam cell formation and cell death of macrophages in association with production of reactive oxygen species.

    Science.gov (United States)

    Okahashi, Nobuo; Okinaga, Toshinori; Sakurai, Atsuo; Terao, Yutaka; Nakata, Masanobu; Nakashima, Keisuke; Shintani, Seikou; Kawabata, Shigetada; Ooshima, Takashi; Nishihara, Tatsuji

    2011-10-01

    Streptococcus sanguinis, a normal inhabitant of the human oral cavity, is a common streptococcal species implicated in infective endocarditis. Herein, we investigated the effects of infection with S. sanguinis on foam cell formation and cell death of macrophages. Infection with S. sanguinis stimulated foam cell formation of THP-1, a human macrophage cell line. At a multiplicity of infection >100, S. sanguinis-induced cell death of the macrophages. Viable bacterial infection was required to trigger cell death because heat-inactivated S. sanguinis did not induce cell death. The production of cytokines interleukin-1β and tumor necrosis factor-α from macrophages was also stimulated during bacterial infection. Inhibition of the production of reactive oxygen species (ROS) resulted in reduced cell death, suggesting an association of ROS with cell death. Furthermore, S. sanguinis-induced cell death appeared to be independent of activation of inflammasomes, because cleavage of procaspase-1 was not evident in infected macrophages. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  4. Activation of peroxisome proliferator-activated receptor-γ (PPARγ) induces cell death through MAPK-dependent mechanism in osteoblastic cells

    International Nuclear Information System (INIS)

    Kim, Sung Hun; Yoo, Chong Il; Kim, Hui Taek; Park, Ji Yeon; Kwon, Chae Hwa; Keun Kim, Yong

    2006-01-01

    The present study was undertaken to determine the role of the mitogen-activated protein kinase (MAPK) subfamilies in cell death induced by PPARγ agonists in osteoblastic cells. Ciglitazone and troglitazone, PPARγ agonists, resulted in a concentration- and time-dependent cell death, which was largely attributed to apoptosis. But a PPARα agonist ciprofibrate did not affect the cell death. Ciglitazone caused reactive oxygen species (ROS) generation and ciglitazone-induced cell death was prevented by antioxidants, suggesting an important role of ROS generation in the ciglitazone-induced cell death. ROS generation and cell death induced by ciglitazone were inhibited by the PPARγ antagonist GW9662. Ciglitazone treatment caused activation of extracellular signal-regulated kinase (ERK) and p38. Activation of ERK was dependent on epidermal growth factor receptor (EGFR) and that of p38 was independent. Ciglitazone-induced cell death was significantly prevented by PD98059, an inhibitor of ERK upstream kinase MEK1/2, and SB203580, a p38 inhibitor. Ciglitazone treatment increased Bax expression and caused a loss of mitochondrial membrane potential, and its effect was prevented by N-acetylcysteine, PD98059, and SB203580. Ciglitazone induced caspase activation, which was prevented by PD98059 and SB203580. The general caspase inhibitor z-DEVD-FMK and the specific inhibitor of caspases-3 DEVD-CHO exerted the protective effect against the ciglitazone-induced cell death. The EGFR inhibitors AG1478 and suramin protected against the ciglitazone-induced cell death. Taken together, these findings suggest that the MAPK signaling pathways play an active role in mediating the ciglitazone-induced cell death of osteoblasts and function upstream of a mitochondria-dependent mechanism. These data may provide a novel insight into potential therapeutic strategies for treatment of osteoporosis

  5. Guidelines and recommendations on yeast cell death nomenclature

    OpenAIRE

    Carmona-Gutierrez, Didac; Bauer, Maria Anna; Zimmermann, Andreas; Aguilera, Andres; Austriaco, Nicanor; Sigrist, Stephan J.

    2018-01-01

    Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing. Here, we propose unified criteria for the definition of accidental, regulated, and programmed forms of cell death in yeast based on a series of mor...

  6. Inhibitor of differentiation 4 (Id4) is a potential tumor suppressor in prostate cancer

    International Nuclear Information System (INIS)

    Carey, Jason PW; Asirvatham, Ananthi J; Galm, Oliver; Ghogomu, Tandeih A; Chaudhary, Jaideep

    2009-01-01

    Inhibitor of differentiation 4 (Id4), a member of the Id gene family is also a dominant negative regulator of basic helix loop helix (bHLH) transcription factors. Some of the functions of Id4 appear to be unique as compared to its other family members Id1, Id2 and Id3. Loss of Id4 gene expression in many cancers in association with promoter hypermethylation has led to the proposal that Id4 may act as a tumor suppressor. In this study we provide functional evidence that Id4 indeed acts as a tumor suppressor and is part of a cancer associated epigenetic re-programming. Data mining was used to demonstrate Id4 expression in prostate cancer. Methylation specific polymerase chain reaction (MSP) analysis was performed to understand molecular mechanisms associated with Id4 expression in prostate cancer cell lines. The effect of ectopic Id4 expression in DU145 cells was determined by cell cycle analysis (3H thymidine incorporation and FACS), expression of androgen receptor, p53 and cyclin dependent kinase inhibitors p27 and p21 by a combination of RT-PCR, real time-PCR, western blot and immuno-cytochemical analysis. Id4 expression was down-regulated in prostate cancer. Id4 expression was also down-regulated in prostate cancer line DU145 due to promoter hyper-methylation. Ectopic Id4 expression in DU145 prostate cancer cell line led to increased apoptosis and decreased cell proliferation due in part by an S-phase arrest. In addition to S-phase arrest, ectopic Id4 expression in PC3 cells also resulted in prolonged G2/M phase. At the molecular level these changes were associated with increased androgen receptor (AR), p21, p27 and p53 expression in DU145 cells. The results suggest that Id4 acts directly as a tumor suppressor by influencing a hierarchy of cellular processes at multiple levels that leads to a decreased cell proliferation and change in morphology that is possibly mediated through induction of previously silenced tumor suppressors

  7. Award nomination for study of cell death in radiation sickness

    Energy Technology Data Exchange (ETDEWEB)

    Ivanitskiy, G

    1985-01-01

    The author discusses the importance of the work entitled Formulation of Theoretical Bases of the Phenomenon of Cell Death and Their Use in Explaining the Pathogenesis of Radiation Sickness, which has been nominated for the 1985 USSR State Prize. The author notes that the study of the nature and mechanisms of cell death from ionizing radiation consumed the efforts of researchers of various specialties for more than 20 years. The author observes that study of the molecular basis of the high radiosensitivity of lymphocytes became the key to understanding the general biological phenomenon of cell death.

  8. Quantification of cell death in developing cerebellum by a 14C tracer method

    International Nuclear Information System (INIS)

    Griffin, W.S.; Woodward, D.J.; Chanda, R.

    1978-01-01

    To study the question of whether or not cell death contributes significantly to normal or stressed postnatal brain development in a way which is biochemically quantifiable, we carried out an experiment to assess the amount of cell death in developing cerebellum. By measuring the loss of DNA content and the loss of 14 C from labelled thymidine previously incorporated into the DNA fraction (DNAF) in X-irradiated neonatal animals, shown by histological methods to have cell death to the degree of degranulating the external granular layer (EGL), we showed that when cells die both label and DNA content are greatly decreased in the cerebellum. Experiments on both normal and malnourished animals showed that cell death does not contribute significantly to cerebellar development in either malnutrition-stressed or normal animals. Here, we present a biochemical tool for assessing cell death and evidence that cell death does not contribute significantly to cerebellar development

  9. The mechanism of radiation-induced interphase death of lymphoid cells: A new hypothesis

    International Nuclear Information System (INIS)

    Eidus, L.K.; Korystov, Yu.N.; Dobrovinskaja, O.R.; Shaposhnikova, V.V.

    1990-01-01

    The interphase death of irradiated rat thymocytes depends on their concentration during postirradiation incubation. The kinetics of pycnosis and cell death determined with the trypan blue exclusion test in the samples with the highest cell concentration (1-2 x 10(7) cells/ml) is consistent with the data available in the literature, whereas the samples with the lowest concentration (2 x 10(5) cells/ml) undergo almost no pycnosis and death after irradiation with doses up to 50 Gy. On the basis of these results, we suggest a new mechanism of interphase death involving an interaction between irradiated thymocytes and the fraction of thymus cells possessing cytocidal activity. The observed correlation between the cytocidal activity and interphase death of thymocytes from animals of different ages favors our mechanism. It was found that the inhibitors which prevent the conjugation of killer cells and their targets do not influence interphase death, while the substances which block the secretion of cytotoxic factors or their action on the target membrane do protect from interphase death. Thus we suggest that the irradiation activates the killer cells to secrete some cytotoxic factors which induce pycnosis and interphase death of thymocytes

  10. Involvement of ethylene and lipid signalling in cadmium-induced programmed cell death in tomato suspension cells

    NARCIS (Netherlands)

    Iakimova, E.T.; Kapchina-Toteva, V.M.; Laarhoven, L.J.; Harren, F.; Woltering, E.J.

    2006-01-01

    Cadmium-induced cell death was studied in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells (line MsK8) treated with CdSO4. Within 24 h, cadmium treatment induced cell death in a concentration-dependent manner. Cell cultures showed recovery after 2¿3 days which indicates the existence

  11. Recipient micro-environment does not dictate the Igh-V restriction specificity of T cell suppressor inducer factor (TsiF) from allogeneic bone marrow chimera in mice

    International Nuclear Information System (INIS)

    Noguchi, M.; Ogasawara, M.; Iwabuchi, K.; Osgasawara, K.; Ishihara, T.; Good, R.A.; Morikawa, K.; Onoe, K.

    1985-01-01

    The authors have ascertained previously from a study of fully allogeneic irradiation chimeras in mice that the H-2 restriction of the suppressor factor (Ly-2 T suppressor factor) is determined by the post-thymic environment protected by the donor cells, rather than by the thymic environment of the recipient. In the present study, the author analyzed differentiation influences that determine the Igh restriction specificities of the suppressor inducer T cell factor(s) (TsiF) that are produced by Ly-1+ splenic T cells in fully allogeneic bone marrow chimeras in mice. AKR mice that had been lethally irradiated and reconstituted with B10 marrow cells, [B10----AKR] chimeras, produced Ly-1 TsiF after hyper-immunization with sheep erythrocytes (SRBC) which suppressed antigen--specifically the primary antibody responses to SRBC that were generated in cells of the same Igh-Vb haplotype of donor strain and not those generated in cells of the recipient Igh-Va type. Similar results were obtained when Ly-1 TsiF from [B6----BALB/c] and [BALB/c----B6] chimeras were analyzed. Furthermore, the Ly-1 TsiF from [BALB/c----B6] chimeras suppressed the primary antibody responses of both BALB/c [H-2d, Igh-Va, Igh-Ca] and BAB-14 (H-2d, Igh-Va, Igh-Cb), but not those of CAL-20 (H-2d, Igh-Vd, Igh-Cd). These results demonstrate clearly that the Ly-1 TsiF from allogeneic bone marrow chimeras are donor Igh-V-restricted and are not influenced by the recipient micro-environment, presumably that were provided by the thymuses of the recipient mice

  12. Non-canonical programmed cell death mechanisms triggered by natural compounds.

    Science.gov (United States)

    Diederich, Marc; Cerella, Claudia

    2016-10-01

    Natural compounds are the fundament of pharmacological treatments and more than 50% of all anticancer drugs are of natural origins or at least derived from scaffolds present in Nature. Over the last 25 years, molecular mechanisms triggered by natural anticancer compounds were investigated. Emerging research showed that molecules of natural origins are useful for both preventive and therapeutic purposes by targeting essential hallmarks and enabling characteristics described by Hanahan and Weinberg. Moreover, natural compounds were able to change the differentiation status of selected cell types. One of the earliest response of cells treated by pharmacologically active compounds is the change of its morphology leading to ultra-structural perturbations: changes in membrane composition, cytoskeleton integrity, alterations of the endoplasmic reticulum, mitochondria and of the nucleus lead to formation of morphological alterations that are a characteristic of both compound and cancer type preceding cell death. Apoptosis and autophagy were traditionally considered as the most prominent cell death or cell death-related mechanisms. By now multiple other cell death modalities were described and most likely involved in response to chemotherapeutic treatment. It can be hypothesized that especially necrosis-related phenotypes triggered by various treatments or evolving from apoptotic or autophagic mechanisms, provide a more efficient therapeutic outcome depending on cancer type and genetic phenotype of the patient. In fact, the recent discovery of multiple regulated forms of necrosis and the initial elucidation of the corresponding cell signaling pathways appear nowadays as important tools to clarify the immunogenic potential of non-canonical forms of cell death induction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. NETs: The missing link between cell death and systemic autoimmune diseases?

    Directory of Open Access Journals (Sweden)

    Felipe eAndrade

    2013-01-01

    Full Text Available For almost 20 years, apoptosis and secondary necrosis have been considered the major source of autoantigens and endogenous adjuvants in the pathogenic model of systemic autoimmune diseases. This focus is justified in part because initial evidence in systemic lupus erythematosus (SLE guided investigators toward the study of apoptosis, but also because other forms of cell death were unknown. To date, it is known that many other forms of cell death occur, and that they vary in their capacity to stimulate as well as inhibit the immune system. Among these, NETosis (an antimicrobial form of death in neutrophils in which nuclear material is extruded from the cell forming extracellular traps, is gaining major interest as a process that may trigger some of the immune features found in SLE, granulomatosis with polyangiitis (formerly Wegener’s granulomatosis and Felty’s syndrome. Although there have been volumes of very compelling studies published on the role of cell death in autoimmunity, no unifying theory has been adopted nor have any successful therapeutics been developed based on this important pathway. The recent inclusion of NETosis into the pathogenic model of autoimmune diseases certainly adds novel insights into this paradigm, but also reveals a previously unappreciated level of complexity and raises many new questions. This review discusses the role of cell death in systemic autoimmune diseases with a focus on apoptosis and NETosis, highlights the current short comings in our understanding of the vast complexity of cell death, and considers the potential shift in the cell death paradigm in autoimmunity. Understanding this complexity is critical in order to develop tools to clearly define the death pathways that are active in systemic autoimmune diseases, identify drivers of disease propagation, and develop novel therapeutics.

  14. Spontaneous and radiation induced cell death in HeLa S3 human carcinoma

    International Nuclear Information System (INIS)

    Zaric, B.; Milosavljevic, B.; Radojcic, M.

    2001-01-01

    Radiation biologists have classified radiation-induced cell death based on cell proliferative capacity to either mitotic or interphase death. Cytologists have revealed two morphologically and biochemically diverse forms of cell death, apoptosis and necrosis. While the knowledge of the former is already well exploited by radiologists, cell susceptibility to apoptosis and necrosis is still under investigation. We studied characteristics of spontaneous cell death, and dose dependence and time course of radiation-induced cell death of human uterine cervix epitheloid carcinoma HeLaS 3 in culture. Cells were irradiated with 2-40 Gy of γ-rays. The effect on growth, viability, morphology and genomic DNA structure were followed 24-72 h after irradiation. Cell viability was evaluated by trypan-blue exclusion assay and cell morphology by in situ DNA staining with propidium iodide. Cell genomic DNA fragmentation pattern was determined by electrophoresis on 2% agarose gels. At all cell densities 25-35% cells were PI positive and their DNA was fragmented to a high molecular size (≥20 kbp), but the internucleosomal ladder was not observed. A significant decrease in viability to 33% was observed 72 h post 40 Gy irradiation. It corresponded to 55% of PI positive cells. A smear of smaller DNA fragments (0.1-1 kbp), 24 h after 10-20 Gy irradiation was considered as proof that the dominant form of radiation-induced cell death was necrosis. It was concluded that the dominant form of radiation-induced cell death in HeLaS 3 population was necrosis and the radiation dose which caused 50% of cell death after 72 h (termed ND 50 ) was between 30-40 Gy. (author)

  15. Bimodal cell death induced by high radiation doses in the radioresistant sf9 insect cell line

    International Nuclear Information System (INIS)

    Chandna, S.

    2003-01-01

    Full text: This study was conducted to investigate the mode(s) of cell death induced by high radiation doses in the highly radioresistant Sf9 insect ovarian cell line. Methods: Cells were exposed to γ-radiation doses 200Gy and 500Gy, harvested at various time intervals (6h-72h) following irradiation, and subjected to cell morphology assay, DNA agarose gel electrophoresis, single cell gel electrophoresis (SCGE; comet assay) and Annexin-V labeling for the detection of membrane phosphatidylserine externalization. Cell morphology was assessed in cells entrapped and fixed in agarose gel directly from the cell suspension, thus preventing the possible loss of fragments/ apoptotic bodies. Surviving fraction of Sf9 cells was 0.01 at 200Gy and 98%) undergoing extensive DNA fragmentation at 500Gy, whereas the frequency of cells with DNA fragmentation was considerably less (∼12%) at 200Gy. Conclusions: While the mode of cell death at 200Gy seems to be different from typical apoptosis, a dose of 500Gy induced bimodal cell death, with typical apoptotic as well as the atypical cell death observed at 200Gy

  16. A shift to organismal stress resistance in programmed cell death mutants.

    Directory of Open Access Journals (Sweden)

    Meredith E Judy

    Full Text Available Animals have many ways of protecting themselves against stress; for example, they can induce animal-wide, stress-protective pathways and they can kill damaged cells via apoptosis. We have discovered an unexpected regulatory relationship between these two types of stress responses. We find that C. elegans mutations blocking the normal course of programmed cell death and clearance confer animal-wide resistance to a specific set of environmental stressors; namely, ER, heat and osmotic stress. Remarkably, this pattern of stress resistance is induced by mutations that affect cell death in different ways, including ced-3 (cell death defective mutations, which block programmed cell death, ced-1 and ced-2 mutations, which prevent the engulfment of dying cells, and progranulin (pgrn-1 mutations, which accelerate the clearance of apoptotic cells. Stress resistance conferred by ced and pgrn-1 mutations is not additive and these mutants share altered patterns of gene expression, suggesting that they may act within the same pathway to achieve stress resistance. Together, our findings demonstrate that programmed cell death effectors influence the degree to which C. elegans tolerates environmental stress. While the mechanism is not entirely clear, it is intriguing that animals lacking the ability to efficiently and correctly remove dying cells should switch to a more global animal-wide system of stress resistance.

  17. Identification of a Novel TGFβ/PKA Signaling Transduceome in Mediating Control of Cell Survival and Metastasis in Colon Cancer

    Science.gov (United States)

    Rajput, Ashwani; Teggart, Carol A.; Brattain, Lisa E.; Weber, Hannah R.; Chowdhury, Aparajita; Brattain, Michael G.

    2011-01-01

    Background Understanding drivers for metastasis in human cancer is important for potential development of therapies to treat metastases. The role of loss of TGFβ tumor suppressor activities in the metastatic process is essentially unknown. Methodology/Principal Findings Utilizing in vitro and in vivo techniques, we have shown that loss of TGFβ tumor suppressor signaling is necessary to allow the last step of the metastatic process - colonization of the metastatic site. This work demonstrates for the first time that TGFβ receptor reconstitution leads to decreased metastatic colonization. Moreover, we have identified a novel TGFβ/PKA tumor suppressor pathway that acts directly on a known cell survival mechanism that responds to stress with the survivin/XIAP dependent inhibition of caspases that effect apoptosis. The linkage between the TGFβ/PKA transduceome signaling and control of metastasis through induction of cell death was shown by TGFβ receptor restoration with reactivation of the TGFβ/PKA pathway in receptor deficient metastatic colon cancer cells leading to control of aberrant cell survival. Conclusion/Significance This work impacts our understanding of the possible mechanisms that are critical to the growth and maintenance of metastases as well as understanding of a novel TGFβ function as a metastatic suppressor. These results raise the possibility that regeneration of attenuated TGFβ signaling would be an effective target in the treatment of metastasis. Our work indicates the clinical potential for developing anti-metastasis therapy based on inhibition of this very important aberrant cell survival mechanism by the multifaceted TGFβ/PKA transduceome induced pathway. Development of effective treatments for metastatic disease is a pressing need since metastases are the major cause of death in solid tumors. PMID:21559296

  18. Identification of a novel TGFβ/PKA signaling transduceome in mediating control of cell survival and metastasis in colon cancer.

    Directory of Open Access Journals (Sweden)

    Sanjib Chowdhury

    2011-05-01

    Full Text Available Understanding drivers for metastasis in human cancer is important for potential development of therapies to treat metastases. The role of loss of TGFβ tumor suppressor activities in the metastatic process is essentially unknown.Utilizing in vitro and in vivo techniques, we have shown that loss of TGFβ tumor suppressor signaling is necessary to allow the last step of the metastatic process - colonization of the metastatic site. This work demonstrates for the first time that TGFβ receptor reconstitution leads to decreased metastatic colonization. Moreover, we have identified a novel TGFβ/PKA tumor suppressor pathway that acts directly on a known cell survival mechanism that responds to stress with the survivin/XIAP dependent inhibition of caspases that effect apoptosis. The linkage between the TGFβ/PKA transduceome signaling and control of metastasis through induction of cell death was shown by TGFβ receptor restoration with reactivation of the TGFβ/PKA pathway in receptor deficient metastatic colon cancer cells leading to control of aberrant cell survival.This work impacts our understanding of the possible mechanisms that are critical to the growth and maintenance of metastases as well as understanding of a novel TGFβ function as a metastatic suppressor. These results raise the possibility that regeneration of attenuated TGFβ signaling would be an effective target in the treatment of metastasis. Our work indicates the clinical potential for developing anti-metastasis therapy based on inhibition of this very important aberrant cell survival mechanism by the multifaceted TGFβ/PKA transduceome induced pathway. Development of effective treatments for metastatic disease is a pressing need since metastases are the major cause of death in solid tumors.

  19. Cell death is induced by ciglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist, independently of PPARγ in human glioma cells

    International Nuclear Information System (INIS)

    Lee, Myoung Woo; Kim, Dae Seong; Kim, Hye Ryung; Kim, Hye Jin; Yang, Jin Mo; Ryu, Somi; Noh, Yoo Hun; Lee, Soo Hyun; Son, Meong Hi; Jung, Hye Lim; Yoo, Keon Hee; Koo, Hong Hoe; Sung, Ki Woong

    2012-01-01

    Highlights: ► Greater than 30 μM ciglitazone induces cell death in glioma cells. ► Cell death by ciglitazone is independent of PPARγ in glioma cells. ► CGZ induces cell death by the loss of MMP via decreased Akt. -- Abstract: Peroxisome proliferator-activated receptor γ (PPARγ) regulates multiple signaling pathways, and its agonists induce apoptosis in various cancer cells. However, their role in cell death is unclear. In this study, the relationship between ciglitazone (CGZ) and PPARγ in CGZ-induced cell death was examined. At concentrations of greater than 30 μM, CGZ, a synthetic PPARγ agonist, activated caspase-3 and induced apoptosis in T98G cells. Treatment of T98G cells with less than 30 μM CGZ effectively induced cell death after pretreatment with 30 μM of the PPARγ antagonist GW9662, although GW9662 alone did not induce cell death. This cell death was also observed when cells were co-treated with CGZ and GW9662, but was not observed when cells were treated with CGZ prior to GW9662. In cells in which PPARγ was down-regulated cells by siRNA, lower concentrations of CGZ (<30 μM) were sufficient to induce cell death, although higher concentrations of CGZ (⩾30 μM) were required to induce cell death in control T98G cells, indicating that CGZ effectively induces cell death in T98G cells independently of PPARγ. Treatment with GW9662 followed by CGZ resulted in a down-regulation of Akt activity and the loss of mitochondrial membrane potential (MMP), which was accompanied by a decrease in Bcl-2 expression and an increase in Bid cleavage. These data suggest that CGZ is capable of inducing apoptotic cell death independently of PPARγ in glioma cells, by down-regulating Akt activity and inducing MMP collapse.

  20. Menadione triggers cell death through ROS-dependent mechanisms involving PARP activation without requiring apoptosis.

    Science.gov (United States)

    Loor, Gabriel; Kondapalli, Jyothisri; Schriewer, Jacqueline M; Chandel, Navdeep S; Vanden Hoek, Terry L; Schumacker, Paul T

    2010-12-15

    Low levels of reactive oxygen species (ROS) can function as redox-active signaling messengers, whereas high levels of ROS induce cellular damage. Menadione generates ROS through redox cycling, and high concentrations trigger cell death. Previous work suggests that menadione triggers cytochrome c release from mitochondria, whereas other studies implicate the activation of the mitochondrial permeability transition pore as the mediator of cell death. We investigated menadione-induced cell death in genetically modified cells lacking specific death-associated proteins. In cardiomyocytes, oxidant stress was assessed using the redox sensor RoGFP, expressed in the cytosol or the mitochondrial matrix. Menadione elicited rapid oxidation in both compartments, whereas it decreased mitochondrial potential and triggered cytochrome c redistribution to the cytosol. Cell death was attenuated by N-acetylcysteine and exogenous glutathione or by overexpression of cytosolic or mitochondria-targeted catalase. By contrast, no protection was observed in cells overexpressing Cu,Zn-SOD or Mn-SOD. Overexpression of antiapoptotic Bcl-X(L) protected against staurosporine-induced cell death, but it failed to confer protection against menadione. Genetic deletion of Bax and Bak, cytochrome c, cyclophilin D, or caspase-9 conferred no protection against menadione-induced cell death. However, cells lacking PARP-1 showed a significant decrease in menadione-induced cell death. Thus, menadione induces cell death through the generation of oxidant stress in multiple subcellular compartments, yet cytochrome c, Bax/Bak, caspase-9, and cyclophilin D are dispensable for cell death in this model. These studies suggest that multiple redundant cell death pathways are activated by menadione, but that PARP plays an essential role in mediating each of them. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Tumor suppressor p53 biology, its role in radioresponse and the analysis of p53 mutation/expression among Filipino breast cancers

    International Nuclear Information System (INIS)

    Deocaris, Custer C.

    2004-01-01

    Ionizing radiation remains one of the most effective tools for the treatment of breast cancer. It combines properties of a potent DNA-damaging agent and high degree of spatial specificity to the target tissue. Nonetheless, there remain considerable differences in the outcome for treatment of tumors of differing histological type treated by radiotherapy. The identification of predictive indicators of radiosensitivity is crucial for selecting patients suited for preoperative radiotherapy as well as those unwarranted for postoperative treatments. To improve prognostication, numerous genes involved in the breast carcinogenesis have been studied and thus far over the last decade several multi-center researches converge on the role of tumor suppressor p53 in tumor biology. The p53 gene is located on the short arm of chromosome 17 and encodes a 53-kd nuclear protein, p-53, also referred to as 'the guardian of the genome', it orchestrates multiple cellular processes such as cell growth control, DNA repair and programmed cell death. During radiotherapy, genotoxic damage induces p53 overexpression in order to control the rate of proliferating damaged cells, repair damage or induce the apoptotic pathway. Its molecular inactivation in a tumor cell, typically by a point mutation, leads to chemo/radio resistance due to the inability of the molecule to trigger p53-dependent programmed cell death

  2. Tumor induced hepatic myeloid derived suppressor cells can cause moderate liver damage.

    Science.gov (United States)

    Eggert, Tobias; Medina-Echeverz, José; Kapanadze, Tamar; Kruhlak, Michael J; Korangy, Firouzeh; Greten, Tim F

    2014-01-01

    Subcutaneous tumors induce the accumulation of myeloid derived suppressor cells (MDSC) not only in blood and spleens, but also in livers of these animals. Unexpectedly, we observed a moderate increase in serum transaminases in mice with EL4 subcutaneous tumors, which prompted us to study the relationship of hepatic MDSC accumulation and liver injury. MDSC were the predominant immune cell population expanding in livers of all subcutaneous tumor models investigated (RIL175, B16, EL4, CT26 and BNL), while liver injury was only observed in EL4 and B16 tumor-bearing mice. Elimination of hepatic MDSC in EL4 tumor-bearing mice using low dose 5-fluorouracil (5-FU) treatment reversed transaminase elevation and adoptive transfer of hepatic MDSC from B16 tumor-bearing mice caused transaminase elevation indicating a direct MDSC mediated effect. Surprisingly, hepatic MDSC from B16 tumor-bearing mice partially lost their damage-inducing potency when transferred into mice bearing non damage-inducing RIL175 tumors. Furthermore, MDSC expansion and MDSC-mediated liver injury further increased with growing tumor burden and was associated with different cytokines including GM-CSF, VEGF, interleukin-6, CCL2 and KC, depending on the tumor model used. In contrast to previous findings, which have implicated MDSC only in protection from T cell-mediated hepatitis, we show that tumor-induced hepatic MDSC themselves can cause moderate liver damage.

  3. The role of tumor suppressor p15Ink4b in the regulation of hematopoietic progenitor cell fate

    International Nuclear Information System (INIS)

    Humeniuk, R; Rosu-Myles, M; Fares, J; Koller, R; Bies, J; Wolff, L

    2013-01-01

    Epigenetic silencing of the tumor suppressor gene p15Ink4b (CDKN2B) is a frequent event in blood disorders like acute myeloid leukemia and myelodysplastic syndromes. The molecular function of p15Ink4b in hematopoietic differentiation still remains to be elucidated. Our previous study demonstrated that loss of p15Ink4b in mice results in skewing of the differentiation pattern of the common myeloid progenitor towards the myeloid lineage. Here, we investigated a function of p15Ink4b tumor suppressor gene in driving erythroid lineage commitment in hematopoietic progenitors. It was found that p15Ink4b is expressed more highly in committed megakaryocyte–erythroid progenitors than granulocyte–macrophage progenitors. More importantly, mice lacking p15Ink4b have lower numbers of primitive red cell progenitors and a severely impaired response to 5-fluorouracil- and phenylhydrazine-induced hematopoietic stress. Introduction of p15Ink4b into multipotential progenitors produced changes at the molecular level, including activation of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) signaling, increase GATA-1, erythropoietin receptor (EpoR) and decrease Pu1, GATA-2 expression. These changes rendered cells more permissive to erythroid commitment and less permissive to myeloid commitment, as demonstrated by an increase in early burst-forming unit-erythroid formation with concomitant decrease in myeloid colonies. Our results indicate that p15Ink4b functions in hematopoiesis, by maintaining proper lineage commitment of progenitors and assisting in rapid red blood cells replenishment following stress

  4. BAX/BAK–Independent Mitoptosis during Cell Death Induced by Proteasome Inhibition?

    OpenAIRE

    Lomonosova, Elena; Ryerse, Jan; Chinnadurai, G.

    2009-01-01

    Proteasome inhibitors induce rapid death of cancer cells. We show that in epithelial cancer cells, such death is associated with dramatic and simultaneous up-regulation of several BH3-only proteins, including BIK, BIM, MCL-1S, NOXA, and PUMA, as well as p53. Elevated levels of these proteins seem to be the result of direct inhibition of their proteasomal degradation, induction of transcription, and active translation. Subsequent cell death is independent of BAX, and probably BAK, and proceeds...

  5. X-ray-induced cell death by apoptosis in the immature rat cerebellum

    International Nuclear Information System (INIS)

    Harmon, B.V.; Allan, D.J.

    1988-01-01

    The cells of the external granular layer (EGL) of the developing cerebellum are known to be particularly sensitive to radiation. In the past, changes induced in this layer by irradiation have been referred to by non-specific terms such as pyknotic cells and the mode of cell death has been assumed to be necrosis. However, in published light micrographs of these dying cells, the appearance is suggestive of apoptosis, a distinctive mode of cell death which occurs spontaneously in normal adult and embryonic tissues and can also be triggered by certain pathological stimuli. This light and transmission electron microscopic study of control and irradiated (7 h post-irradiation) rat cerebellum from 18 day fetuses and 5 day-old neonates showed that the cell death was effected by apoptosis. The apoptosis was markedly enhanced by x-irradiation and quantification of the cell death in the EGL of 5 day-old rats exposed to 4, 8, 25, 100, and 400 cGy x-irradiation demonstrated that there was a positive dose response relationship. The extent of cell death by apoptosis which was 0.2% in control, ranged from 0.8% after 4 cGy to 62.3% after 400 cGy x-irradiation. The recognition that cell death by apoptosis can be a major component of x-irradiation damage has important implications for radiobiological studies

  6. Mitochondrial and Cell Death Mechanisms in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Lee J. Martin

    2010-03-01

    Full Text Available Alzheimer’s disease (AD, Parkinson’s disease (PD and amyotrophic lateral sclerosis (ALS are the most common human adult-onset neurodegenerative diseases. They are characterized by prominent age-related neurodegeneration in selectively vulnerable neural systems. Some forms of AD, PD, and ALS are inherited, and genes causing these diseases have been identified. Nevertheless, the mechanisms of the neuronal cell death are unresolved. Morphological, biochemical, genetic, as well as cell and animal model studies reveal that mitochondria could have roles in this neurodegeneration. The functions and properties of mitochondria might render subsets of selectively vulnerable neurons intrinsically susceptible to cellular aging and stress and overlying genetic variations, triggering neurodegeneration according to a cell death matrix theory. In AD, alterations in enzymes involved in oxidative phosphorylation, oxidative damage, and mitochondrial binding of Aβ and amyloid precursor protein have been reported. In PD, mutations in putative mitochondrial proteins have been identified and mitochondrial DNA mutations have been found in neurons in the substantia nigra. In ALS, changes occur in mitochondrial respiratory chain enzymes and mitochondrial cell death proteins. Transgenic mouse models of human neurodegenerative disease are beginning to reveal possible principles governing the biology of selective neuronal vulnerability that implicate mitochondria and the mitochondrial permeability transition pore. This review summarizes how mitochondrial pathobiology might contribute to neuronal death in AD, PD, and ALS and could serve as a target for drug therapy.

  7. Staurosporine induces different cell death forms in cultured rat astrocytes

    International Nuclear Information System (INIS)

    Simenc, Janez; Lipnik-Stangelj, Metoda

    2012-01-01

    Astroglial cells are frequently involved in malignant transformation. Besides apoptosis, necroptosis, a different form of regulated cell death, seems to be related with glioblastoma genesis, proliferation, angiogenesis and invasion. In the present work we elucidated mechanisms of necroptosis in cultured astrocytes, and compared them with apoptosis, caused by staurosporine. Cultured rat cortical astrocytes were used for a cell death studies. Cell death was induced by different concentrations of staurosporine, and modified by inhibitors of apoptosis (z-vad-fmk) and necroptosis (nec-1). Different forms of a cell death were detected using flow cytometry. We showed that staurosporine, depending on concentration, induces both, apoptosis as well as necroptosis. Treatment with 10 −7 M staurosporine increased apoptosis of astrocytes after the regeneration in a staurosporine free medium. When caspases were inhibited, apoptosis was attenuated, while necroptosis was slightly increased. Treatment with 10 −6 M staurosporine induced necroptosis that occurred after the regeneration of astrocytes in a staurosporine free medium, as well as without regeneration period. Necroptosis was significantly attenuated by nec-1 which inhibits RIP1 kinase. On the other hand, the inhibition of caspases had no effect on necroptosis. Furthermore, staurosporine activated RIP1 kinase increased the production of reactive oxygen species, while an antioxidant BHA significantly attenuated necroptosis. Staurosporine can induce apoptosis and/or necroptosis in cultured astrocytes via different signalling pathways. Distinction between different forms of cell death is crucial in the studies of therapy-induced necroptosis

  8. The Apoptosome: Heart and Soul of the Cell Death Machine

    Directory of Open Access Journals (Sweden)

    Arul M. Chinnaiyan

    1999-04-01

    Full Text Available Apoptosis is a fundamental biologic process by which metazoan cells orchestrate their own self-demise. Genetic analyses of the nematode C elegans identified three core components of the suicide apparatus which include CED-3, CED-4, and CED-9. An analogous set of core constituents exists in mammalian cells and includes caspase-9, Apaf-1, and bcl-2/xL, respectively. CED-3 and CED-4, along with their mammalian counterparts, function to kill cells, whereas CED-9 and its mammalian equivalents protect cells from death. These central components biochemically intermingle in a ternary complex recently dubbed the “apoptosome.” The C elegans protein EGL-1 and its mammalian counterparts, pro-apoptotic members of the bcl-2 family, induce cell death by disrupting apoptosome interactions. Thus, EGL-1 may represent a primordial signal integrator for the apoptosome. Various biochemical processes including oligomerization, adenosine triphosphate ATP/dATP binding, and cytochrome c interaction play a role in regulating the ternary death complex. Recent studies suggest that cell death receptors, such as CD95, may amplify their suicide signal by activating the apoptosome. These mutual associations by core components of the suicide apparatus provide a molecular framework in which diverse death signals likely interface. Understanding the apoptosome and its cellular connections will facilitate the design of novel therapeutic strategies for cancer and other disease states in which apoptosis plays a pivotal role.

  9. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    International Nuclear Information System (INIS)

    Pan, Mu-Yun; Shen, Yuh-Chiang; Lu, Chien-Hsing; Yang, Shu-Yi; Ho, Tsing-Fen; Peng, Yu-Ta; Chang, Chia-Che

    2012-01-01

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified as an

  10. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Mu-Yun [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Shen, Yuh-Chiang [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); National Research Institute of Chinese Medicine, Taipei, Taiwan (China); Lu, Chien-Hsing [Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Obstetrics and Gynecology, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Yang, Shu-Yi [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Ho, Tsing-Fen [Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Peng, Yu-Ta [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chang, Chia-Che, E-mail: chia_che@dragon.nchu.edu.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China)

    2012-12-15

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified

  11. Interphase death of dividing cells. Kinetics of death of cultured Chinese hamster fibroblasts after irradiation with various doses

    International Nuclear Information System (INIS)

    Kublik, L.N.; Veksler, A.M.; Ehjdus, L.Kh.

    1989-01-01

    In studying the kinetics of interphase death (ID) of cultured Chinese hamster cells after irradiation with doses of 100 to 800 Gy the authors showed an increase in the ID rate with increasing radiation dose; the presence of serum in the medium both during and after irradiation prevents the cell death

  12. Tumor-reactive immune cells protect against metastatic tumor and induce immunoediting of indolent but not quiescent tumor cells.

    Science.gov (United States)

    Payne, Kyle K; Keim, Rebecca C; Graham, Laura; Idowu, Michael O; Wan, Wen; Wang, Xiang-Yang; Toor, Amir A; Bear, Harry D; Manjili, Masoud H

    2016-09-01

    Two major barriers to cancer immunotherapy include tumor-induced immune suppression mediated by myeloid-derived suppressor cells and poor immunogenicity of the tumor-expressing self-antigens. To overcome these barriers, we reprogrammed tumor-immune cell cross-talk by combined use of decitabine and adoptive immunotherapy, containing tumor-sensitized T cells and CD25(+) NKT cells. Decitabine functioned to induce the expression of highly immunogenic cancer testis antigens in the tumor, while also reducing the frequency of myeloid-derived suppressor cells and the presence of CD25(+) NKT cells rendered T cells, resistant to remaining myeloid-derived suppressor cells. This combinatorial therapy significantly prolonged survival of animals bearing metastatic tumor cells. Adoptive immunotherapy also induced tumor immunoediting, resulting in tumor escape and associated disease-related mortality. To identify a tumor target that is incapable of escape from the immune response, we used dormant tumor cells. We used Adriamycin chemotherapy or radiation therapy, which simultaneously induce tumor cell death and tumor dormancy. Resultant dormant cells became refractory to additional doses of Adriamycin or radiation therapy, but they remained sensitive to tumor-reactive immune cells. Importantly, we discovered that dormant tumor cells contained indolent cells that expressed low levels of Ki67 and quiescent cells that were Ki67 negative. Whereas the former were prone to tumor immunoediting and escape, the latter did not demonstrate immunoediting. Our results suggest that immunotherapy could be highly effective against quiescent dormant tumor cells. The challenge is to develop combinatorial therapies that could establish a quiescent type of tumor dormancy, which would be the best target for immunotherapy. © The Author(s).

  13. Trial watch: Immunogenic cell death induction by anticancer chemotherapeutics.

    Science.gov (United States)

    Garg, Abhishek D; More, Sanket; Rufo, Nicole; Mece, Odeta; Sassano, Maria Livia; Agostinis, Patrizia; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2017-01-01

    The expression "immunogenic cell death" (ICD) refers to a functionally unique form of cell death that facilitates (instead of suppressing) a T cell-dependent immune response specific for dead cell-derived antigens. ICD critically relies on the activation of adaptive responses in dying cells, culminating with the exposure or secretion of immunostimulatory molecules commonly referred to as "damage-associated molecular patterns". Only a few agents can elicit bona fide ICD, including some clinically established chemotherapeutics such as doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin. In this Trial Watch, we discuss recent progress on the development of ICD-inducing chemotherapeutic regimens, focusing on studies that evaluate clinical efficacy in conjunction with immunological biomarkers.

  14. The potential for tumor suppressor gene therapy in head and neck cancer.

    Science.gov (United States)

    Birkeland, Andrew C; Ludwig, Megan L; Spector, Matthew E; Brenner, J Chad

    2016-01-01

    Head and neck squamous cell carcinoma remains a highly morbid and fatal disease. Importantly, genomic sequencing of head and neck cancers has identified frequent mutations in tumor suppressor genes. While targeted therapeutics increasingly are being investigated in head and neck cancer, the majority of these agents are against overactive/overexpressed oncogenes. Therapy to restore lost tumor suppressor gene function remains a key and under-addressed niche in trials for head and neck cancer. Recent advances in gene editing have captured the interest of both the scientific community and the public. As our technology for gene editing and gene expression modulation improves, addressing lost tumor suppressor gene function in head and neck cancers is becoming a reality. This review will summarize new techniques, challenges to implementation, future directions, and ethical ramifications of gene therapy in head and neck cancer.

  15. Cell death in the pathogenesis of systemic lupus erythematosus and lupus nephritis.

    Science.gov (United States)

    Mistry, Pragnesh; Kaplan, Mariana J

    2017-12-01

    Nephritis is one of the most severe complications of systemic lupus erythematosus (SLE). One key characteristic of lupus nephritis (LN) is the deposition of immune complexes containing nucleic acids and/or proteins binding to nucleic acids and autoantibodies recognizing these molecules. A variety of cell death processes are implicated in the generation and externalization of modified nuclear autoantigens and in the development of LN. Among these processes, apoptosis, primary and secondary necrosis, NETosis, necroptosis, pyroptosis, and autophagy have been proposed to play roles in tissue damage and immune dysregulation. Cell death occurs in healthy individuals during conditions of homeostasis yet autoimmunity does not develop, at least in part, because of rapid clearance of dying cells. In SLE, accelerated cell death combined with a clearance deficiency may lead to the accumulation and externalization of nuclear autoantigens and to autoantibody production. In addition, specific types of cell death may modify autoantigens and alter their immunogenicity. These modified molecules may then become novel targets of the immune system and promote autoimmune responses in predisposed hosts. In this review, we examine various cell death pathways and discuss how enhanced cell death, impaired clearance, and post-translational modifications of proteins could contribute to the development of lupus nephritis. Published by Elsevier Inc.

  16. The ubiquitin-homology protein, DAP-1, associates with tumor necrosis factor receptor (p60) death domain and induces apoptosis.

    Science.gov (United States)

    Liou, M L; Liou, H C

    1999-04-09

    The tumor necrosis factor receptor, p60 (TNF-R1), transduces death signals via the association of its cytoplasmic domain with several intracellular proteins. By screening a mammalian cDNA library using the yeast two-hybrid cloning technique, we isolated a ubiquitin-homology protein, DAP-1, which specifically interacts with the cytoplasmic death domain of TNF-R1. Sequence analysis reveals that DAP-1 shares striking sequence homology with the yeast SMT3 protein that is essential for the maintenance of chromosome integrity during mitosis (Meluh, P. B., and Koshland, D. (1995) Mol. Biol. Cell 6, 793-807). DAP-1 is nearly identical to PIC1, a protein that interacts with the PML tumor suppressor implicated in acute promyelocytic leukemia (Boddy, M. N., Howe, K., Etkin, L. D., Solomon, E., and Freemont, P. S. (1996) Oncogene 13, 971-982), and the sentrin protein, which associates with the Fas death receptor (Okura, T., Gong, L., Kamitani, T., Wada, T., Okura, I., Wei, C. F., Chang, H. M., and Yeh, E. T. (1996) J. Immunol. 157, 4277-4281). The in vivo interaction between DAP-1 and TNF-R1 was further confirmed in mammalian cells. In transient transfection assays, overexpression of DAP-1 suppresses NF-kappaB/Rel activity in 293T cells, a human kidney embryonic carcinoma cell line. Overexpression of either DAP-1 or sentrin causes apoptosis of TNF-sensitive L929 fibroblast cell line, as well as TNF-resistant osteosarcoma cell line, U2OS. Furthermore, the dominant negative Fas-associated death domain protein (FADD) protein blocks the cell death induced by either DAP-1 or FADD. Collectively, these observations highly suggest a role for DAP-1 in mediating TNF-induced cell death signaling pathways, presumably through the recruitment of FADD death effector.

  17. Triptolide induces lysosomal-mediated programmed cell death in MCF-7 breast cancer cells

    Directory of Open Access Journals (Sweden)

    Owa C

    2013-09-01

    Full Text Available Chie Owa, Michael E Messina Jr, Reginald HalabyDepartment of Biology, Montclair State University, Montclair, NJ, USABackground: Breast cancer is a major cause of death; in fact, it is the most common type, in order of the number of global deaths, of cancer in women worldwide. This research seeks to investigate how triptolide, an extract from the Chinese herb Tripterygium wilfordii Hook F, induces apoptosis in MCF-7 human breast cancer cells. Accumulating evidence suggests a role for lysosomal proteases in the activation of apoptosis. However, there is also some controversy regarding the direct participation of lysosomal proteases in activation of key apoptosis-related caspases and release of mitochondrial cytochrome c. In the present study, we demonstrate that triptolide induces an atypical, lysosomal-mediated apoptotic cell death in MCF-7 cells because they lack caspase-3.Methods: MCF-7 cell death was characterized via cellular morphology, chromatin condensation, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide colorimetric cell growth inhibition assay and the expression levels of proapoptotic proteins. Acridine orange and LysoTracker® staining were performed to visualize lysosomes. Lysosomal enzymatic activity was monitored using an acid phosphatase assay and western blotting of cathepsin B protein levels in the cytosolic fraction, which showed increased enzymatic activity in drug-treated cells.Results: These experiments suggest that triptolide-treated MCF-7 cells undergo atypical apoptosis and that, during the early stages, lysosomal enzymes leak into the cytosol, indicating lysosomal membrane permeability.Conclusion: Our results suggest that further studies are warranted to investigate triptolide's potential as an anticancer therapeutic agent.Keywords: triptolide, MCF-7 breast cancer cells, apoptosis, lysosomes, lysosomal membrane permeabilization (LMP

  18. Terminalia Chebula provides protection against dual modes of necroptotic and apoptotic cell death upon death receptor ligation.

    Science.gov (United States)

    Lee, Yoonjung; Byun, Hee Sun; Seok, Jeong Ho; Park, Kyeong Ah; Won, Minho; Seo, Wonhyoung; Lee, So-Ra; Kang, Kidong; Sohn, Kyung-Cheol; Lee, Ill Young; Kim, Hyeong-Geug; Son, Chang Gue; Shen, Han-Ming; Hur, Gang Min

    2016-04-27

    Death receptor (DR) ligation elicits two different modes of cell death (necroptosis and apoptosis) depending on the cellular context. By screening a plant extract library from cells undergoing necroptosis or apoptosis, we identified a water extract of Terminalia chebula (WETC) as a novel and potent dual inhibitor of DR-mediated cell death. Investigation of the underlying mechanisms of its anti-necroptotic and anti-apoptotic action revealed that WETC or its constituents (e.g., gallic acid) protected against tumor necrosis factor-induced necroptosis via the suppression of TNF-induced ROS without affecting the upstream signaling events. Surprisingly, WETC also provided protection against DR-mediated apoptosis by inhibition of the caspase cascade. Furthermore, it activated the autophagy pathway via suppression of mTOR. Of the WETC constituents, punicalagin and geraniin appeared to possess the most potent anti-apoptotic and autophagy activation effect. Importantly, blockage of autophagy with pharmacological inhibitors or genetic silencing of Atg5 selectively abolished the anti-apoptotic function of WETC. These results suggest that WETC protects against dual modes of cell death upon DR ligation. Therefore, WETC might serve as a potential treatment for diseases characterized by aberrantly sensitized apoptotic or non-apoptotic signaling cascades.

  19. An extensive microarray analysis of AAL-toxin-induced cell death in Arabidopsis thaliana brings new insights into the complexity of programmed cell death in plants

    NARCIS (Netherlands)

    Gechev, T.S.; Gadjev, I.Z.; Hille, J.

    2004-01-01

    A T-DNA knockout of the Arabidopsis homologue of the tomato disease resistance gene Asc was obtained. The asc gene renders plants sensitive to programmed cell death (PCD) triggered by the fungal AAL toxin. To obtain more insights into the nature of AAL-toxin-induced cell death and to identify genes

  20. Hop/STI1 modulates retinal proliferation and cell death independent of PrPC

    International Nuclear Information System (INIS)

    Arruda-Carvalho, Maithe; Njaine, Brian; Silveira, Mariana S.; Linden, Rafael; Chiarini, Luciana B.

    2007-01-01

    Hop/STI1 is a co-chaperone adaptor protein for Hsp70/Hsp90 complexes. Hop/STI1 is found extracellularly and modulates cell death and differentiation through interaction with the prion protein (PrP C ). Here, we investigated the expression of hop/STI1 and its role upon cell proliferation and cell death in the developing retina. Hop/STI1 is more expressed in developing rat retina than in the mature tissue. Hop/STI1 blocks retinal cell death in the neuroblastic layer (NBL) in a PrP C dependent manner, but failed to protect ganglion cells against axotomy-induced cell death. An antibody raised against hop/STI1 (α-STI1) blocked both ganglion cell and NBL cell death independent of PrP C . cAMP/PKA, ERK, PI3K and PKC signaling pathways were not involved in these effects. Hop/STI1 treatment reduced proliferation, while α-STI1 increased proliferation in the developing retina, both independent of PrP C . We conclude that hop/STI1 can modulate both proliferation and cell death in the developing retina independent of PrP C

  1. Genetic alterations in head and neck squamous cell carcinomas

    Directory of Open Access Journals (Sweden)

    Nagai M.A.

    1999-01-01

    Full Text Available The genetic alterations observed in head and neck cancer are mainly due to oncogene activation (gain of function mutations and tumor suppressor gene inactivation (loss of function mutations, leading to deregulation of cell proliferation and death. These genetic alterations include gene amplification and overexpression of oncogenes such as myc, erbB-2, EGFR and cyclinD1 and mutations, deletions and hypermethylation leading to p16 and TP53 tumor suppressor gene inactivation. In addition, loss of heterozygosity in several chromosomal regions is frequently observed, suggesting that other tumor suppressor genes not yet identified could be involved in the tumorigenic process of head and neck cancers. The exact temporal sequence of the genetic alterations during head and neck squamous cell carcinoma (HNSCC development and progression has not yet been defined and their diagnostic or prognostic significance is controversial. Advances in the understanding of the molecular basis of head and neck cancer should help in the identification of new markers that could be used for the diagnosis, prognosis and treatment of the disease.

  2. Sertoli cell death by apoptosis in the immature rat testis following x-irradiation

    International Nuclear Information System (INIS)

    Allan, D.J.; Gobe, G.C.; Harmon, B.V.

    1988-01-01

    The importance of the morphological study of cell death has recently been emphasized by the recognition that the ultrastructural features of dying cells allow categorization of the death as either apoptosis or necrosis. This classification enables inferences to be drawn about the mechanism and biological significance of the death occurring in a particular set of circumstances. In this study, Sertoli cell death induced in the immature testis of three and four day old rats by 5 Gy (500 rads) x-irradiation was described by light and transmission electron microscopy with the objective of categorizing the death as apoptosis or necrosis. The testes were examined 1, 2, 3, 4, 8, and 24 h after irradiation. Following irradiation, there was a wave of apoptosis of the Sertoli cells starting in three to four hours and reaching a peak between four and eight hours. At 24 hours, only 61% of the expected number of Sertoli cells remained. These findings are in accord with recent ultrastructural reports that ionizing radiation induces cell death by apoptosis in rapidly proliferating cell populations. New insights into the pathogenesis of radiation-induced cell death might thus be expected to stem from future elucidation of the general molecular events involved in triggering apoptosis

  3. Combined effects of starvation and butyrate on autophagy-dependent gingival epithelial cell death.

    Science.gov (United States)

    Evans, M; Murofushi, T; Tsuda, H; Mikami, Y; Zhao, N; Ochiai, K; Kurita-Ochiai, T; Yamamoto, M; Otsuka, K; Suzuki, N

    2017-06-01

    Bacteria in the dental biofilm surrounding marginal gingival grooves cause periodontal diseases. Numerous bacteria within the biofilm consume nutrients from the gingival crevicular fluid. Furthermore, some gram-negative bacteria in mature dental biofilms produce butyrate. Thus, gingival epithelial cells in close proximity to mature dental biofilms are at risk of both starvation and exposure to butyrate. In the present study, we determined the combined effects of starvation and butyrate exposure on gingival epithelial cell death and the underlying mechanisms. The Ca9-22 cell line was used as an in vitro counterpart of gingival epithelial cells. Cell death was measured as the amount of total DNA in the dead cells using SYTOX Green dye, which penetrates through membranes of dead cells and emits fluorescence when it intercalates into double-stranded DNA. AMP-activated protein kinase (AMPK) activity, the amount of autophagy, and acetylation of histone H3 were determined using western blot. Gene expression levels of microtubule-associated protein 1 light chain 3b (lc3b) were determined using quantitative reverse transcription-polymerase chain reaction. Butyrate-induced cell death occurred in a dose-dependent manner whether cells were starved or fed. However, the induction of cell death was two to four times higher when cells were placed under starvation conditions compared to when they were fed. Moreover, both starvation and butyrate exposure induced AMPK activity and autophagy. While AMPK inactivation resulted in decreased autophagy and butyrate-induced cell death under conditions of starvation, AMPK activation resulted in butyrate-induced cell death when cells were fed. Combined with the results of our previous report, which demonstrated butyrate-induced autophagy-dependent cell death, the results of this study suggest that the combination of starvation and butyrate exposure activates AMPK inducing autophagy and subsequent cell death. Notably, this combination markedly

  4. Immunogenic Cell Death Induced by Ginsenoside Rg3: Significance in Dendritic Cell-based Anti-tumor Immunotherapy.

    Science.gov (United States)

    Son, Keum-Joo; Choi, Ki Ryung; Lee, Seog Jae; Lee, Hyunah

    2016-02-01

    Cancer is one of the leading causes of morbidity and mortality worldwide; therefore there is a need to discover new therapeutic modules with improved efficacy and safety. Immune-(cell) therapy is a promising therapeutic strategy for the treatment of intractable cancers. The effectiveness of certain chemotherapeutics in inducing immunogenic tumor cell death thus promoting cancer eradication has been reported. Ginsenoside Rg3 is a ginseng saponin that has antitumor and immunomodulatory activity. In this study, we treated tumor cells with Rg3 to verify the significance of inducing immunogenic tumor cell death in antitumor therapy, especially in DC-based immunotherapy. Rg3 killed the both immunogenic (B16F10 melanoma cells) and non-immunogenic (LLC: Lewis Lung Carcinoma cells) tumor cells by inducing apoptosis. Surface expression of immunogenic death markers including calreticulin and heat shock proteins and the transcription of relevant genes were increased in the Rg3-dying tumor. Increased calreticulin expression was directly related to the uptake of dying tumor cells by dendritic cells (DCs): the proportion of CRT(+) CD11c(+) cells was increased in the Rg3-treated group. Interestingly, tumor cells dying by immunogenic cell death secreted IFN-γ, an effector molecule for antitumor activity in T cells. Along with the Rg3-induced suppression of pro-angiogenic (TNF-α) and immunosuppressive cytokine (TGF-β) secretion, IFN-γ production from the Rg3-treated tumor cells may also indicate Rg3 as an effective anticancer immunotherapeutic strategy. The data clearly suggests that Rg3-induced immunogenic tumor cell death due its cytotoxic effect and its ability to induce DC function. This indicates that Rg3 may be an effective immunotherapeutic strategy.

  5. Dying cells protect survivors from radiation-induced cell death in Drosophila.

    Directory of Open Access Journals (Sweden)

    Amber Bilak

    2014-03-01

    Full Text Available We report a phenomenon wherein induction of cell death by a variety of means in wing imaginal discs of Drosophila larvae resulted in the activation of an anti-apoptotic microRNA, bantam. Cells in the vicinity of dying cells also become harder to kill by ionizing radiation (IR-induced apoptosis. Both ban activation and increased protection from IR required receptor tyrosine kinase Tie, which we identified in a genetic screen for modifiers of ban. tie mutants were hypersensitive to radiation, and radiation sensitivity of tie mutants was rescued by increased ban gene dosage. We propose that dying cells activate ban in surviving cells through Tie to make the latter cells harder to kill, thereby preserving tissues and ensuring organism survival. The protective effect we report differs from classical radiation bystander effect in which neighbors of irradiated cells become more prone to death. The protective effect also differs from the previously described effect of dying cells that results in proliferation of nearby cells in Drosophila larval discs. If conserved in mammals, a phenomenon in which dying cells make the rest harder to kill by IR could have implications for treatments that involve the sequential use of cytotoxic agents and radiation therapy.

  6. miR-339-5p regulates the p53 tumor-suppressor pathway by targeting MDM2

    DEFF Research Database (Denmark)

    Jansson, M D; Djodji Damas, Nkerorema; Lees, M

    2014-01-01

    MicroRNAs (miRNAs) regulate many key cancer-relevant pathways and may themselves possess oncogenic or tumor-suppressor functions. Consequently, miRNA dysregulation has been shown to be a prominent feature in many human cancers. The p53 tumor suppressor acts as a negative regulator of cell prolife...... tumor cells. Furthermore, we show that a negative correlation between miR-339-5p and MDM2 expression exists in human cancer, implying that the interaction is important for cancer development.Oncogene advance online publication, 2 June 2014; doi:10.1038/onc.2014.130....

  7. Molecular biology III - Oncogenes and tumor suppressor genes

    International Nuclear Information System (INIS)

    Giaccia, Amato J.

    1996-01-01

    Purpose: The purpose of this course is to introduce to radiation oncologists the basic concepts of tumorigenesis, building on the information that will be presented in the first and second part of this series of lectures. Objective: Our objective is to increase the current understanding of radiation oncologists with the process of tumorigenesis, especially focusing on genes that are altered in many tumor types that are potential candidates for novel molecular strategies. As strategies to treat cancer of cancer are becoming more sophisticated, it will be important for both the practitioner and academician to develop a basic understanding of the function of cancer 'genes'. This will be the third in a series of refresher courses that are meant to address recent advances in Cancer Biology in a way that both clinicians without previous knowledge of molecular biology or experienced researchers will find interesting. The lecture will begin with a basic overview of tumorigenesis; methods of detecting chromosome/DNA alterations, approaches used to isolate oncogenes and tumor suppressor genes, and their role in cell killing by apoptosis. Special attention will be given to oncogenes and tumor suppressor genes that are modulated by ionizing radiation and the tumor microenvironment. We will relate the biology of oncogenes and tumor suppressor genes to basic aspects of radiation biology that would be important in clinical practice. Finally, we will review recent studies on the prognostic significance of p53 mutations and apoptosis in tumor specimens. The main point of this lecture is to relate both researcher and clinician what are the therapeutic ramifications of oncogene and tumor suppressor gene mutations found in human neoptasia

  8. Heterogeneity reduces sensitivity of cell death for TNF-Stimuli

    Directory of Open Access Journals (Sweden)

    Schliemann Monica

    2011-12-01

    Full Text Available Abstract Background Apoptosis is a form of programmed cell death essential for the maintenance of homeostasis and the removal of potentially damaged cells in multicellular organisms. By binding its cognate membrane receptor, TNF receptor type 1 (TNF-R1, the proinflammatory cytokine Tumor Necrosis Factor (TNF activates pro-apoptotic signaling via caspase activation, but at the same time also stimulates nuclear factor κB (NF-κB-mediated survival pathways. Differential dose-response relationships of these two major TNF signaling pathways have been described experimentally and using mathematical modeling. However, the quantitative analysis of the complex interplay between pro- and anti-apoptotic signaling pathways is an open question as it is challenging for several reasons: the overall signaling network is complex, various time scales are present, and cells respond quantitatively and qualitatively in a heterogeneous manner. Results This study analyzes the complex interplay of the crosstalk of TNF-R1 induced pro- and anti-apoptotic signaling pathways based on an experimentally validated mathematical model. The mathematical model describes the temporal responses on both the single cell level as well as the level of a heterogeneous cell population, as observed in the respective quantitative experiments using TNF-R1 stimuli of different strengths and durations. Global sensitivity of the heterogeneous population was quantified by measuring the average gradient of time of death versus each population parameter. This global sensitivity analysis uncovers the concentrations of Caspase-8 and Caspase-3, and their respective inhibitors BAR and XIAP, as key elements for deciding the cell's fate. A simulated knockout of the NF-κB-mediated anti-apoptotic signaling reveals the importance of this pathway for delaying the time of death, reducing the death rate in the case of pulse stimulation and significantly increasing cell-to-cell variability. Conclusions Cell

  9. ABCE1 is a highly conserved RNA silencing suppressor.

    Directory of Open Access Journals (Sweden)

    Kairi Kärblane

    Full Text Available ATP-binding cassette sub-family E member 1 (ABCE1 is a highly conserved protein among eukaryotes and archaea. Recent studies have identified ABCE1 as a ribosome-recycling factor important for translation termination in mammalian cells, yeast and also archaea. Here we report another conserved function of ABCE1. We have previously described AtRLI2, the homolog of ABCE1 in the plant Arabidopsis thaliana, as an endogenous suppressor of RNA silencing. In this study we show that this function is conserved: human ABCE1 is able to suppress RNA silencing in Nicotiana benthamiana plants, in mammalian HEK293 cells and in the worm Caenorhabditis elegans. Using co-immunoprecipitation and mass spectrometry, we found a number of potential ABCE1-interacting proteins that might support its function as an endogenous suppressor of RNA interference. The interactor candidates are associated with epigenetic regulation, transcription, RNA processing and mRNA surveillance. In addition, one of the identified proteins is translin, which together with its binding partner TRAX supports RNA interference.

  10. Low-frequency quantitative ultrasound imaging of cell death in vivo

    International Nuclear Information System (INIS)

    Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J.; Papanicolau, Naum; Tadayyon, Hadi; Lee, Justin; Zubovits, Judit; Sadeghian, Alireza; Karshafian, Raffi; Al-Mahrouki, Azza; Giles, Anoja; Kolios, Michael C.

    2013-01-01

    Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r 2 = 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency, in

  11. Low-frequency quantitative ultrasound imaging of cell death in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J. [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Papanicolau, Naum; Tadayyon, Hadi [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Lee, Justin [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Zubovits, Judit [Department of Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Sadeghian, Alireza [Department of Computer Science, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Karshafian, Raffi [Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Al-Mahrouki, Azza; Giles, Anoja [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Kolios, Michael C. [Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5, Canada and Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)

    2013-08-15

    Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r{sup 2}= 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency

  12. Calpain Determines the Propensity of Adult Hippocampal Neural Stem Cells to Autophagic Cell Death Following Insulin Withdrawal.

    Science.gov (United States)

    Chung, Kyung Min; Park, Hyunhee; Jung, Seonghee; Ha, Shinwon; Yoo, Seung-Jun; Woo, Hanwoong; Lee, Hyang Ju; Kim, Seong Who; Kim, Eun-Kyoung; Moon, Cheil; Yu, Seong-Woon

    2015-10-01

    Programmed cell death (PCD) has significant effects on the function of neural stem cells (NSCs) during brain development and degeneration. We have previously reported that adult rat hippocampal neural stem (HCN) cells underwent autophagic cell death (ACD) rather than apoptosis following insulin withdrawal despite their intact apoptotic capabilities. Here, we report a switch in the mode of cell death in HCN cells with calpain as a critical determinant. In HCN cells, calpain 1 expression was barely detectable while calpain 2 was predominant. Inhibition of calpain in insulin-deprived HCN cells further augmented ACD. In contrast, expression of calpain 1 switched ACD to apoptosis. The proteasome inhibitor lactacystin blocked calpain 2 degradation and elevated the intracellular Ca(2+) concentration. In combination, these effects potentiated calpain activity and converted the mode of cell death to apoptosis. Our results indicate that low calpain activity, due to absence of calpain 1 and degradation of calpain 2, results in a preference for ACD over apoptosis in insulin-deprived HCN cells. On the other hand, conditions leading to high calpain activity completely switch the mode of cell death to apoptosis. This is the first report on the PCD mode switching mechanism in NSCs. The dynamic change in calpain activity through the proteasome-mediated modulation of the calpain and intracellular Ca(2+) levels may be the critical contributor to the demise of NSCs. Our findings provide a novel insight into the complex mechanisms interconnecting autophagy and apoptosis and their roles in the regulation of NSC death. © 2015 AlphaMed Press.

  13. FMSP-Nanoparticles Induced Cell Death on Human Breast Adenocarcinoma Cell Line (MCF-7 Cells: Morphometric Analysis

    Directory of Open Access Journals (Sweden)

    Firdos Alam Khan

    2018-05-01

    Full Text Available Currently, breast cancer treatment mostly revolves around radiation therapy and surgical interventions, but often these treatments do not provide satisfactory relief to the patients and cause unmanageable side-effects. Nanomaterials show promising results in treating cancer cells and have many advantages such as high biocompatibility, bioavailability and effective therapeutic capabilities. Interestingly, fluorescent magnetic nanoparticles have been used in many biological and diagnostic applications, but there is no report of use of fluorescent magnetic submicronic polymer nanoparticles (FMSP-nanoparticles in the treatment of human breast cancer cells. In the present study, we tested the effect of FMSP-nanoparticles on human breast cancer cells (MCF-7. We tested different concentrations (1.25, 12.5 and 50 µg/mL of FMSP-nanoparticles in MCF-7 cells and evaluated the nanoparticles response morphometrically. Our results revealed that FMSP-nanoparticles produced a concentration dependent effect on the cancer cells, a dose of 1.25 µg/mL produced no significant effect on the cancer cell morphology and cell death, whereas dosages of 12.5 and 50 µg/mL resulted in significant nuclear augmentation, disintegration, chromatic condensation followed by dose dependent cell death. Our results demonstrate that FMSP-nanoparticles induce cell death in MCF-7 cells and may be a potential anti-cancer agent for breast cancer treatment.

  14. Cadmium toxicity in cultured tomato cells - Role of ethylene, proteases and oxidative stress in cell death signaling

    NARCIS (Netherlands)

    Iakimova, E.T.; Woltering, E.J.; Kapchina-Toteva, V.M.; Harren, F.J.M.; Cristescu, S.M.

    2008-01-01

    Our aim was to investigate the ability of cadmium to induce programmed cell death in tomato suspension cells and to determine the involvement of proteolysis, oxidative stress and ethylene. Tomato suspension cells were exposed to treatments with CdSO4 and cell death was calculated after fluorescein

  15. A novel proapoptotic gene PANO encodes a post-translational modulator of the tumor suppressor p14ARF

    Energy Technology Data Exchange (ETDEWEB)

    Watari, Akihiro; Li, Yang; Higashiyama, Shinji; Yutsudo, Masuo, E-mail: yutsudo@biken.osaka-u.ac.jp

    2012-02-01

    The protein p14ARF is a known tumor suppressor protein controlling cell proliferation and survival, which mainly localizes in nucleoli. However, the regulatory mechanisms that govern its activity or expression remain unclear. Here, we report that a novel proapoptotic nucleolar protein, PANO, modulates the expression and activity of p14ARF in HeLa cells. Overexpression of PANO enhances the stability of p14ARF protein by protecting it from degradation, resulting in an increase in p14ARF expression levels. Overexpression of PANO also induces apoptosis under low serum conditions. This effect is dependent on the nucleolar localization of PANO and inhibited by knocking-down p14ARF. Alternatively, PANO siRNA treated cells exhibit a reduction in p14ARF protein levels. In addition, ectopic expression of PANO suppresses the tumorigenicity of HeLa cells in nude mice. These results indicate that PANO is a new apoptosis-inducing gene by modulating the tumor suppressor protein, p14ARF, and may itself be a new candidate tumor suppressor gene.

  16. Zebularine exerts its antiproliferative activity through S phase delay and cell death in human malignant mesothelioma cells.

    Science.gov (United States)

    Takemura, Yukitoshi; Satoh, Motohiko; Hatanaka, Kenichi; Kubota, Shunichiro

    2018-04-24

    Malignant mesothelioma is an asbestos-related aggressive tumor and current therapy remains ineffective. Zebularine as a DNA methyltransferase (DNMT) inhibitor has an anti-tumor effect in several human cancer cells. The aim of the present study was to investigate whether zebularine could induce antiproliferative effect in human malignant mesothelioma cells. Zebularine induced cell growth inhibition in a dose-dependent manner. In addition, zebularine dose-dependently decreased expression of DNMT1 in all malignant mesothelioma cells tested. Cell cycle analysis indicated that zebularine induced S phase delay. Zebularine also induced cell death in malignant mesothelioma cells. In contrast, zebularine did not induce cell growth inhibition and cell death in human normal fibroblast cells. These results suggest that zebularine has a potential for the treatment of malignant mesothelioma by inhibiting cell growth and inducing cell death.

  17. Love is a battlefield: programmed cell death during fertilization.

    Science.gov (United States)

    Heydlauff, Juliane; Groß-Hardt, Rita

    2014-03-01

    Plant development and growth is sustained by the constant generation of tremendous amounts of cells, which become integrated into various types of tissues and organs. What is all too often overlooked is that this thriving life also requires the targeted degeneration of selected cells, which undergo cell death according to genetically encoded programmes or environmental stimuli. The side-by-side existence of generation and demise is particularly evident in the haploid phase of the flowering plants cycle. Here, the lifespan of terminally differentiated accessory cells contrasts with that of germ cells, which by definition live on to form the next generation. In fact, with research in recent years it is becoming increasingly clear that the gametophytes of flowering plants constitute an attractive and powerful system for investigating the molecular mechanisms underlying selective cell death.

  18. Transducer of ERBB2.1 (TOB1) as a Tumor Suppressor: A Mechanistic Perspective.

    Science.gov (United States)

    Lee, Hun Seok; Kundu, Juthika; Kim, Ryong Nam; Shin, Young Kee

    2015-12-15

    Transducer of ERBB2.1 (TOB1) is a tumor-suppressor protein, which functions as a negative regulator of the receptor tyrosine-kinase ERBB2. As most of the other tumor suppressor proteins, TOB1 is inactivated in many human cancers. Homozygous deletion of TOB1 in mice is reported to be responsible for cancer development in the lung, liver, and lymph node, whereas the ectopic overexpression of TOB1 shows anti-proliferation, and a decrease in the migration and invasion abilities on cancer cells. Biochemical studies revealed that the anti-proliferative activity of TOB1 involves mRNA deadenylation and is associated with the reduction of both cyclin D1 and cyclin-dependent kinase (CDK) expressions and the induction of CDK inhibitors. Moreover, TOB1 interacts with an oncogenic signaling mediator, β-catenin, and inhibits β-catenin-regulated gene transcription. TOB1 antagonizes the v-akt murine thymoma viral oncogene (AKT) signaling and induces cancer cell apoptosis by activating BCL2-associated X (BAX) protein and inhibiting the BCL-2 and BCL-XL expressions. The tumor-specific overexpression of TOB1 results in the activation of other tumor suppressor proteins, such as mothers against decapentaplegic homolog 4 (SMAD4) and phosphatase and tensin homolog-10 (PTEN), and blocks tumor progression. TOB1-overexpressing cancer cells have limited potential of growing as xenograft tumors in nude mice upon subcutaneous implantation. This review addresses the molecular basis of TOB1 tumor suppressor function with special emphasis on its regulation of intracellular signaling pathways.

  19. Transducer of ERBB2.1 (TOB1 as a Tumor Suppressor: A Mechanistic Perspective

    Directory of Open Access Journals (Sweden)

    Hun Seok Lee

    2015-12-01

    Full Text Available Transducer of ERBB2.1 (TOB1 is a tumor-suppressor protein, which functions as a negative regulator of the receptor tyrosine-kinase ERBB2. As most of the other tumor suppressor proteins, TOB1 is inactivated in many human cancers. Homozygous deletion of TOB1 in mice is reported to be responsible for cancer development in the lung, liver, and lymph node, whereas the ectopic overexpression of TOB1 shows anti-proliferation, and a decrease in the migration and invasion abilities on cancer cells. Biochemical studies revealed that the anti-proliferative activity of TOB1 involves mRNA deadenylation and is associated with the reduction of both cyclin D1 and cyclin-dependent kinase (CDK expressions and the induction of CDK inhibitors. Moreover, TOB1 interacts with an oncogenic signaling mediator, β-catenin, and inhibits β-catenin-regulated gene transcription. TOB1 antagonizes the v-akt murine thymoma viral oncogene (AKT signaling and induces cancer cell apoptosis by activating BCL2-associated X (BAX protein and inhibiting the BCL-2 and BCL-XL expressions. The tumor-specific overexpression of TOB1 results in the activation of other tumor suppressor proteins, such as mothers against decapentaplegic homolog 4 (SMAD4 and phosphatase and tensin homolog-10 (PTEN, and blocks tumor progression. TOB1-overexpressing cancer cells have limited potential of growing as xenograft tumors in nude mice upon subcutaneous implantation. This review addresses the molecular basis of TOB1 tumor suppressor function with special emphasis on its regulation of intracellular signaling pathways.

  20. METACASPASE9 modulates autophagy to confine cell death to the target cells during Arabidopsis vascular xylem differentiation

    Directory of Open Access Journals (Sweden)

    Sacha Escamez

    2016-02-01

    Full Text Available We uncovered that the level of autophagy in plant cells undergoing programmed cell death determines the fate of the surrounding cells. Our approach consisted of using Arabidopsis thaliana cell cultures capable of differentiating into two different cell types: vascular tracheary elements (TEs that undergo programmed cell death (PCD and protoplast autolysis, and parenchymatic non-TEs that remain alive. The TE cell type displayed higher levels of autophagy when expression of the TE-specific METACASPASE9 (MC9 was reduced using RNAi (MC9-RNAi. Misregulation of autophagy in the MC9-RNAi TEs coincided with ectopic death of the non-TEs, implying the existence of an autophagy-dependent intercellular signalling from within the TEs towards the non-TEs. Viability of the non-TEs was restored when AUTOPHAGY2 (ATG2 was downregulated specifically in MC9-RNAi TEs, demonstrating the importance of autophagy in the spatial confinement of cell death. Our results suggest that other eukaryotic cells undergoing PCD might also need to tightly regulate their level of autophagy to avoid detrimental consequences for the surrounding cells.

  1. Monocytic myeloid-derived suppressor cells as prognostic factor in chronic myeloid leukaemia patients treated with dasatinib.

    Science.gov (United States)

    Giallongo, Cesarina; Parrinello, Nunziatina L; La Cava, Piera; Camiolo, Giuseppina; Romano, Alessandra; Scalia, Marina; Stagno, Fabio; Palumbo, Giuseppe A; Avola, Roberto; Li Volti, Giovanni; Tibullo, Daniele; Di Raimondo, Francesco

    2018-02-01

    Myeloid suppressor cells are a heterogeneous group of myeloid cells that are increased in patients with chronic myeloid leukaemia (CML) inducing T cell tolerance. In this study, we found that therapy with tyrosine kinase inhibitors (TKI) decreased the percentage of granulocytic MDSC, but only patients treated with dasatinib showed a significant reduction in the monocytic subset (M-MDSC). Moreover, a positive correlation was observed between number of persistent M-MDSC and the value of major molecular response in dasatinib-treated patients. Serum and exosomes from patients with CML induced conversion of monocytes from healthy volunteers into immunosuppressive M-MDSC, suggesting a bidirectional crosstalk between CML cells and MDSC. Overall, we identified M-MDSC as prognostic factors in patients treated with dasatinib. It might be of interest to understand whether MDSC may be a candidate predictive markers of relapse risk following TKI discontinuation, suggesting their potential significance as practice of precision medicine. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  2. NF-{kappa}B p50 promotes tumor cell invasion through negative regulation of invasion suppressor gene CRMP-1 in human lung adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Gao [Cancer Research Center, College of Medicine, National Taiwan University, Taipei, Taiwan (China); National Center of Excellence for Clinical Trial and Research, National Taiwan University, Hospital, Taipei, Taiwan (China); Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Yeh, P Y [Cancer Research Center, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Department of Oncology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10016, Taiwan (China); Lu, Y -S [Cancer Research Center, College of Medicine, National Taiwan University, Taipei, Taiwan (China); National Center of Excellence for Clinical Trial and Research, National Taiwan University, Hospital, Taipei, Taiwan (China); Department of Oncology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10016, Taiwan, ROC (China); Chang, W C [Cancer Research Center, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Kuo, M -L [Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Cheng, A -L [Cancer Research Center, College of Medicine, National Taiwan University, Taipei, Taiwan (China); National Center of Excellence for Clinical Trial and Research, National Taiwan University, Hospital, Taipei, Taiwan (China); Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan (China); Department of Oncology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10016, Taiwan (China); Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 10016, Taiwan (China)], E-mail: alcheng@ntu.edu.tw

    2008-11-14

    Lung adenocarcinoma Cl1-5 cells were selected from parental Cl1-0 cells based on their high metastatic potential. In a previous study, CRMP-1, an invasion suppressor gene, was shown to be suppressed in Cl1-5 cells. However, the regulation of CRMP-1 expression has not been explored. In this study, we showed nuclear factor-{kappa}B controls CRMP-1 expression. The electromobility shift assay showed that while Cl1-0 cells exhibited low NF-{kappa}B activity in response to TNF-{alpha}, an abundance of basal and TNF-{alpha}-induced NF-{kappa}B-DNA complex was detected in Cl1-5 cells. Supershift-coupled EMSA and Western blotting of nuclear proteins, however, revealed p50 protein, but not classic p65/p50 heterodimer in the complex. ChIP and EMSA demonstrated that p50 binds to a {kappa}B site residing between -1753 and -1743 of the CRMP-1 promoter region. Transfection of antisense p50 gene into Cl1-5 cells increased the CRMP-1 protein level and decreased the invasive activity of Cl1-5 cells.

  3. NF-κB p50 promotes tumor cell invasion through negative regulation of invasion suppressor gene CRMP-1 in human lung adenocarcinoma cells

    International Nuclear Information System (INIS)

    Gao Ming; Yeh, P.Y.; Lu, Y.-S.; Chang, W.C.; Kuo, M.-L.; Cheng, A.-L.

    2008-01-01

    Lung adenocarcinoma Cl1-5 cells were selected from parental Cl1-0 cells based on their high metastatic potential. In a previous study, CRMP-1, an invasion suppressor gene, was shown to be suppressed in Cl1-5 cells. However, the regulation of CRMP-1 expression has not been explored. In this study, we showed nuclear factor-κB controls CRMP-1 expression. The electromobility shift assay showed that while Cl1-0 cells exhibited low NF-κB activity in response to TNF-α, an abundance of basal and TNF-α-induced NF-κB-DNA complex was detected in Cl1-5 cells. Supershift-coupled EMSA and Western blotting of nuclear proteins, however, revealed p50 protein, but not classic p65/p50 heterodimer in the complex. ChIP and EMSA demonstrated that p50 binds to a κB site residing between -1753 and -1743 of the CRMP-1 promoter region. Transfection of antisense p50 gene into Cl1-5 cells increased the CRMP-1 protein level and decreased the invasive activity of Cl1-5 cells

  4. Genetic analysis of suppressors of the PF10 mutation in Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    Dutcher, S.K.; Gibbons, W.; Inwood, W.B.

    1988-01-01

    A mutation at the PF10 locus of the unicellular green alga Chlamydomonas reinhardtii leads to abnormal cell motility. The asymmetric form of the ciliary beat stroke characteristic of wild-type flagella is modified by this mutation to a nearly symmetric beat. We report here that this abnormal motility is a conditional phenotype that depends on light intensity. In the absence of light or under low light intensities, the motility is more severely impaired than at higher light intensities. By UV mutagenesis we obtained 11 intragenic and 70 extragenic strains that show reversion of the pf10 motility phenotype observed in low light. The intragenic events reverted the motility phenotype of the pf10 mutation completely. The extragenic events define at least seven suppressor loci; these map to linkage groups IV, VII, IX, XI, XII and XVII. Suppressor mutations at two of the seven loci (LIS1 and LIS2) require light for their suppressor activity. Forty-eight of the 70 extragenic suppressors were examined in heterozygous diploid cells; 47 of these mutants were recessive to the wild-type allele and one mutant (bop5-1) was dominant to the wild-type allele. Complementation analysis of the 47 recessive mutants showed unusual patterns. Most mutants within a recombinationally defined group failed to complement one another, although there were pairs that showed intra-allelic complementation. Additionally, some of the mutants at each recombinationally defined locus failed to complement mutants at other loci. They define dominant enhancers of one another

  5. Morphologic categorization of cell death induced by mild hyperthermia and comparison with death induced by ionizing radiation and cytotoxic drugs

    International Nuclear Information System (INIS)

    Allan, D.J.; Harmon, B.V.

    1986-01-01

    This paper presents a summary of the morphological categorization of cell death, results of two in vivo studies on the cell death induced by mild hyperthermia in rat small intestine and mouse mastocytoma, and a comparison of the cell death induced by hyperthermia, radiation and cytotoxic drugs. Two distinct forms of cell death, apoptosis and necrosis, can be recognized on morphologic grounds. Apoptosis appears to be a process of active cellular self-destruction to which a biologically meaningful role can usually be attributed, whereas necrosis is a passive degenerative phenomenon that results from irreversible cellular injury. Light and transmission electron microscopic studies showed that lower body hyperthermia (43 degrees C for 30 min) induced only apoptosis of intestinal epithelial cells, and of lymphocytes, plasma cells, and eosinophils. In the mastocytoma, hyperthermia (43 degrees C for 15 min) produced widespread tumor necrosis and also enhanced apoptosis of tumor cells. Ionizing radiation and cytotoxic drugs are also known to induce apoptosis in a variety of tissues. It is attractive to speculate that DNA damage by each agent is the common event which triggers the same process of active cellular self-destruction that characteristically effects selective cell deletion in normal tissue homeostasis

  6. Delineating the cell death mechanisms associated with skin electroporation.

    Science.gov (United States)

    Schultheis, Katherine; Smith, Trevor R F; Kiosses, William B; Kraynyak, Kimberly A; Wong, Amelia; Oh, Janet; Broderick, Kate Elizabeth

    2018-06-28

    The immune responses elicited following delivery of DNA vaccines to the skin has previously been shown to be significantly enhanced by the addition of electroporation (EP) to the treatment protocol. Principally, EP increases the transfection of pDNA into the resident skin cells. In addition to increasing the levels of in vivo transfection, the physical insult induced by EP is associated with activation of innate pathways which are believed to mediate an adjuvant effect, further enhancing DNA vaccine responses. Here, we have investigated the possible mechanisms associated with this adjuvant effect, primarily focusing on the cell death pathways associated with the skin EP procedure independent of pDNA delivery. Using the minimally invasive CELLECTRA®-3P intradermal electroporation device that penetrates the epidermal and dermal layers of the skin, we have investigated apoptotic and necrotic cell death in relation to the vicinity of the electrode needles and electric field generated. Employing the well-established TUNEL assay, we detected apoptosis beginning as early as one hour after EP and peaking at the 4 hour time point. The majority of the apoptotic events were detected in the epidermal region directly adjacent to the electrode needle. Using a novel propidium iodide in vivo necrotic cell death assay, we detected necrotic events concentrated in the epidermal region adjacent to the electrode. Furthermore, we detected up-regulation of calreticulin expression on skin cells after EP, thus labeling these cells for uptake by dendritic cells and macrophages. These results allow us to delineate the cell death mechanisms occurring in the skin following intradermal EP independently of pDNA delivery. We believe these events contribute to the adjuvant effect observed following electroporation at the skin treatment site.

  7. The splicing mutant of the human tumor suppressor protein DFNA5 induces programmed cell death when expressed in the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Van Rossom, Sofie; Op de Beeck, Ken; Franssens, Vanessa; Swinnen, Erwin; Schepers, Anne; Ghillebert, Ruben; Caldara, Marina; Van Camp, Guy; Winderickx, Joris

    2012-01-01

    DFNA5 was first identified as a gene responsible for autosomal dominant deafness. Different mutations were found, but they all resulted in exon 8 skipping during splicing and premature termination of the protein. Later, it became clear that the protein also has a tumor suppression function and that it can induce apoptosis. Epigenetic silencing of the DFNA5 gene is associated with different types of cancers, including gastric and colorectal cancers as well as breast tumors. We introduced the wild-type and mutant DFNA5 allele in the yeast Saccharomyces cerevisiae. The expression of the wild-type protein was well tolerated by the yeast cells, although the protein was subject of degradation and often deposited in distinct foci when cells entered the diauxic shift. In contrast, cells had problems to cope with mutant DFNA5 and despite an apparent compensatory reduction in expression levels, the mutant protein still triggered a marked growth defect, which in part can be ascribed to its interaction with mitochondria. Consistently, cells with mutant DFNA5 displayed significantly increased levels of ROS and signs of programmed cell death. The latter occurred independently of the yeast caspase, Mca1, but involved the mitochondrial fission protein, Fis1, the voltage-dependent anion channel protein, Por1 and the mitochondrial adenine nucleotide translocators, Aac1 and Aac3. Recent data proposed DFNA5 toxicity to be associated to a globular domain encoded by exon 2–6. We confirmed these data by showing that expression of solely this domain confers a strong growth phenotype. In addition, we identified a point mutant in this domain that completely abrogated its cytotoxicity in yeast as well as human Human Embryonic Kidney 293T cells (HEK293T). Combined, our data underscore that the yeast system offers a valuable tool to further dissect the apoptotic properties of DFNA5.

  8. The splicing mutant of the human tumor suppressor protein DFNA5 induces programmed cell death when expressed in the yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Van Rossom, Sofie [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium); Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Op de Beeck, Ken [Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Franssens, Vanessa; Swinnen, Erwin [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium); Schepers, Anne [Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Ghillebert, Ruben; Caldara, Marina [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium); Van Camp, Guy [Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp, Wilrijk-Antwerp (Belgium); Winderickx, Joris, E-mail: guy.vancamp@ua.ac.be, E-mail: joris.winderickx@bio.kuleuven.be [Department of Biology, Functional Biology, KU Leuven, Leuven-Heverlee (Belgium)

    2012-07-25

    DFNA5 was first identified as a gene responsible for autosomal dominant deafness. Different mutations were found, but they all resulted in exon 8 skipping during splicing and premature termination of the protein. Later, it became clear that the protein also has a tumor suppression function and that it can induce apoptosis. Epigenetic silencing of the DFNA5 gene is associated with different types of cancers, including gastric and colorectal cancers as well as breast tumors. We introduced the wild-type and mutant DFNA5 allele in the yeast Saccharomyces cerevisiae. The expression of the wild-type protein was well tolerated by the yeast cells, although the protein was subject of degradation and often deposited in distinct foci when cells entered the diauxic shift. In contrast, cells had problems to cope with mutant DFNA5 and despite an apparent compensatory reduction in expression levels, the mutant protein still triggered a marked growth defect, which in part can be ascribed to its interaction with mitochondria. Consistently, cells with mutant DFNA5 displayed significantly increased levels of ROS and signs of programmed cell death. The latter occurred independently of the yeast caspase, Mca1, but involved the mitochondrial fission protein, Fis1, the voltage-dependent anion channel protein, Por1 and the mitochondrial adenine nucleotide translocators, Aac1 and Aac3. Recent data proposed DFNA5 toxicity to be associated to a globular domain encoded by exon 2–6. We confirmed these data by showing that expression of solely this domain confers a strong growth phenotype. In addition, we identified a point mutant in this domain that completely abrogated its cytotoxicity in yeast as well as human Human Embryonic Kidney 293T cells (HEK293T). Combined, our data underscore that the yeast system offers a valuable tool to further dissect the apoptotic properties of DFNA5.

  9. Apoptotic Cell Death Induced by Resveratrol Is Partially Mediated by the Autophagy Pathway in Human Ovarian Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Fangfang Lang

    Full Text Available Resveratrol (trans-3,4,5'-trihydroxystilbene is an active compound in food, such as red grapes, peanuts, and berries. Resveratrol exhibits an anticancer effect on various human cancer cells. However, the mechanism of resveratrol-induced anti-cancer effect at the molecular level remains to be elucidated. In this study, the mechanism underlying the anti-cancer effect of resveratrol in human ovarian cancer cells (OVCAR-3 and Caov-3 was investigated using various molecular biology techniques, such as flow cytometry, western blotting, and RNA interference, with a major focus on the potential role of autophagy in resveratrol-induced apoptotic cell death. We demonstrated that resveratrol induced reactive oxygen species (ROS generation, which triggers autophagy and subsequent apoptotic cell death. Resveratrol induced ATG5 expression and promoted LC3 cleavage. The apoptotic cell death induced by resveratrol was attenuated by both pharmacological and genetic inhibition of autophagy. The autophagy inhibitor chloroquine, which functions at the late stage of autophagy, significantly reduced resveratrol-induced cell death and caspase 3 activity in human ovarian cancer cells. We also demonstrated that targeting ATG5 by siRNA also suppressed resveratrol-induced apoptotic cell death. Thus, we concluded that a common pathway between autophagy and apoptosis exists in resveratrol-induced cell death in OVCAR-3 human ovarian cancer cells.

  10. Apoptosis-inducing factor plays a critical role in caspase-independent, pyknotic cell death in hydrogen peroxide-exposed cells.

    Science.gov (United States)

    Son, Young-Ok; Jang, Yong-Suk; Heo, Jung-Sun; Chung, Wan-Tae; Choi, Ki-Choon; Lee, Jeong-Chae

    2009-06-01

    It has been proposed that continuously generated hydrogen peroxide (H(2)O(2)) inhibits typical apoptosis and instead initiates an alternate, apoptosis-inducing factor (AIF)-dependent process. Aside from the role of AIF, however, the detailed morphological characterization of H(2)O(2)-induced cell death is not complete. This study examined the cellular mechanism(s) by which the continuous presence of H(2)O(2) induces cell death. We also further analyzed the precise role of AIF by inhibiting its expression with siRNA. Exposure of cells to H(2)O(2) generated by glucose oxidase caused mitochondrion-mediated, caspase-independent cell death. In addition, H(2)O(2) exposure resulted in cell shrinkage and chromatin condensation without nuclear fragmentation, indicating that H(2)O(2) stimulates a pyknotic cell death. Further analysis of AIF-transfected cells clearly demonstrated that nuclear translocation of AIF is the most important event required for nuclear condensation, phosphatidyl serine translocation, and ultimately cell death in H(2)O(2)-exposed cells. Furthermore, ATP was rapidly and severely depleted in cells exposed to H(2)O(2) generated by glucose oxidase but not by H(2)O(2) added as a bolus. Suppression of the H(2)O(2)-mediated ATP depletion by 3-aminobenzamide led to a significant increase of nuclear fragmentation in glucose oxidase-exposed cells. Collectively, these findings suggest that an acute energy reduction by H(2)O(2) causes caspase-independent and AIF-dependent cell death.

  11. The natural product peiminine represses colorectal carcinoma tumor growth by inducing autophagic cell death

    International Nuclear Information System (INIS)

    Lyu, Qing; Tou, Fangfang; Su, Hong; Wu, Xiaoyong; Chen, Xinyi; Zheng, Zhi

    2015-01-01

    Autophagy is evolutionarily conservative in eukaryotic cells that engulf cellular long-lived proteins and organelles, and it degrades the contents through fusion with lysosomes, via which the cell acquires recycled building blocks for the synthesis of new molecules. In this study, we revealed that peiminine induces cell death and enhances autophagic flux in colorectal carcinoma HCT-116 cells. We determined that peiminine enhances the autophagic flux by repressing the phosphorylation of mTOR through inhibiting upstream signals. Knocking down ATG5 greatly reduced the peiminine-induced cell death in wild-type HCT-116 cells, while treating Bax/Bak-deficient cells with peiminine resulted in significant cell death. In summary, our discoveries demonstrated that peiminine represses colorectal carcinoma cell proliferation and cell growth by inducing autophagic cell death. - Highlights: • Peiminine induces autophagy and upregulates autophagic flux. • Peiminine represses colorectal carcinoma tumor growth. • Peiminine induces autophagic cell death. • Peiminine represses mTOR phosphorylation by influencing PI3K/Akt and AMPK pathway

  12. The natural product peiminine represses colorectal carcinoma tumor growth by inducing autophagic cell death

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Qing [School of Life Sciences, Tsinghua University, Beijing, 100084 (China); Key Lab in Healthy Science and Technology, Division of Life Science, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055 (China); Tou, Fangfang [Jiangxi Provincial Key Lab of Oncology Translation Medicine, Jiangxi Cancer Hospital, Nanchang, 330029 (China); Su, Hong; Wu, Xiaoyong [First Affiliated Hospital, Guiyang College of Traditional Chinese Medicine, Guiyang, 550002 (China); Chen, Xinyi [Department of Hematology and Oncology, Beijing University of Chinese Medicine, Beijing, 100029 (China); Zheng, Zhi, E-mail: zheng_sheva@hotmail.com [Jiangxi Provincial Key Lab of Oncology Translation Medicine, Jiangxi Cancer Hospital, Nanchang, 330029 (China)

    2015-06-19

    Autophagy is evolutionarily conservative in eukaryotic cells that engulf cellular long-lived proteins and organelles, and it degrades the contents through fusion with lysosomes, via which the cell acquires recycled building blocks for the synthesis of new molecules. In this study, we revealed that peiminine induces cell death and enhances autophagic flux in colorectal carcinoma HCT-116 cells. We determined that peiminine enhances the autophagic flux by repressing the phosphorylation of mTOR through inhibiting upstream signals. Knocking down ATG5 greatly reduced the peiminine-induced cell death in wild-type HCT-116 cells, while treating Bax/Bak-deficient cells with peiminine resulted in significant cell death. In summary, our discoveries demonstrated that peiminine represses colorectal carcinoma cell proliferation and cell growth by inducing autophagic cell death. - Highlights: • Peiminine induces autophagy and upregulates autophagic flux. • Peiminine represses colorectal carcinoma tumor growth. • Peiminine induces autophagic cell death. • Peiminine represses mTOR phosphorylation by influencing PI3K/Akt and AMPK pathway.

  13. Genetic and biochemical evidence that haploinsufficiency of the Nf1 tumor suppressor gene modulates melanocyte and mast cell fates in vivo.

    Science.gov (United States)

    Ingram, D A; Yang, F C; Travers, J B; Wenning, M J; Hiatt, K; New, S; Hood, A; Shannon, K; Williams, D A; Clapp, D W

    2000-01-03

    Neurofibromatosis type 1 (NF1) is a common autosomal-dominant disorder characterized by cutaneous neurofibromas infiltrated with large numbers of mast cells, melanocyte hyperplasia, and a predisposition to develop malignant neoplasms. NF1 encodes a GTPase activating protein (GAP) for Ras. Consistent with Knudson's "two hit" model of tumor suppressor genes, leukemias and malignant solid tumors in NF1 patients frequently demonstrate somatic loss of the normal NF1 allele. However, the phenotypic and biochemical consequences of heterozygous inactivation of Nf1 are largely unknown. Recently neurofibromin, the protein encoded by NF1, was shown to negatively regulate Ras activity in Nf1-/- murine myeloid hematopoietic cells in vitro through the c-kit receptor tyrosine kinase (dominant white spotting, W). Since the W and Nf1 locus appear to function along a common developmental pathway, we generated mice with mutations at both loci to examine potential interactions in vivo. Here, we show that haploinsufficiency at Nf1 perturbs cell fates in mast cells in vivo, and partially rescues coat color and mast cell defects in W(41) mice. Haploinsufficiency at Nf1 also increased mast cell proliferation, survival, and colony formation in response to Steel factor, the ligand for c-kit. Furthermore, haploinsufficiency was associated with enhanced Ras-mitogen-activated protein kinase activity, a major downstream effector of Ras, via wild-type and mutant (W(41)) c-kit receptors. These observations identify a novel interaction between c-kit and neurofibromin in vivo, and offer experimental evidence that haploinsufficiency of Nf1 alters both cellular and biochemical phenotypes in two cell lineages that are affected in individuals with NF1. Collectively, these data support the emerging concept that heterozygous inactivation of tumor suppressor genes may have profound biological effects in multiple cell types.

  14. Negative regulation of TLR4 via targeting of the proinflammatory tumor suppressor PDCD4 by the microRNA miR-21.

    LENUS (Irish Health Repository)

    Sheedy, FJ

    2009-11-29

    The tumor suppressor PDCD4 is a proinflammatory protein that promotes activation of the transcription factor NF-kappaB and suppresses interleukin 10 (IL-10). Here we found that mice deficient in PDCD4 were protected from lipopolysaccharide (LPS)-induced death. The induction of NF-kappaB and IL-6 by LPS required PDCD4, whereas LPS enhanced IL-10 induction in cells lacking PDCD4. Treatment of human peripheral blood mononuclear cells with LPS resulted in lower PDCD4 expression, which was due to induction of the microRNA miR-21 via the adaptor MyD88 and NF-kappaB. Transfection of cells with a miR-21 precursor blocked NF-kappaB activity and promoted IL-10 production in response to LPS, whereas transfection with antisense oligonucleotides to miR-21 or targeted protection of the miR-21 site in Pdcd4 mRNA had the opposite effect. Thus, miR-21 regulates PDCD4 expression after LPS stimulation.

  15. An unusual characteristic "flower-like" pattern: flash suppressor burns.

    Science.gov (United States)

    Gurcan, Altun

    2012-04-01

    The case on contact shots from firearms with a flash suppressor is rare. When a rifle fitted with a flash suppressor is fired, the emerging soot-laden gas in the barrel escapes from the slits of the flash suppressor. If the shot is contact or near contact, the flash suppressor will produce a characteristic "flower-like" pattern of seared, blackened zones around the entrance. This paper presents the injury pattern of the flash suppressor in a 29-year-old man who committed suicide with a G3 automatic infantry rifle.

  16. Drug-Induced Liver Injury: Cascade of Events Leading to Cell Death, Apoptosis or Necrosis

    Directory of Open Access Journals (Sweden)

    Andrea Iorga

    2017-05-01

    Full Text Available Drug-induced liver injury (DILI can broadly be divided into predictable and dose dependent such as acetaminophen (APAP and unpredictable or idiosyncratic DILI (IDILI. Liver injury from drug hepatotoxicity (whether idiosyncratic or predictable results in hepatocyte cell death and inflammation. The cascade of events leading to DILI and the cell death subroutine (apoptosis or necrosis of the cell depend largely on the culprit drug. Direct toxins to hepatocytes likely induce oxidative organelle stress (such as endoplasmic reticulum (ER and mitochondrial stress leading to necrosis or apoptosis, while cell death in idiosyncratic DILI (IDILI is usually the result of engagement of the innate and adaptive immune system (likely apoptotic, involving death receptors (DR. Here, we review the hepatocyte cell death pathways both in direct hepatotoxicity such as in APAP DILI as well as in IDILI. We examine the known signaling pathways in APAP toxicity, a model of necrotic liver cell death. We also explore what is known about the genetic basis of IDILI and the molecular pathways leading to immune activation and how these events can trigger hepatotoxicity and cell death.

  17. Cell death is induced by ciglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist, independently of PPARγ in human glioma cells.

    Science.gov (United States)

    Lee, Myoung Woo; Kim, Dae Seong; Kim, Hye Ryung; Kim, Hye Jin; Yang, Jin Mo; Ryu, Somi; Noh, Yoo Hun; Lee, Soo Hyun; Son, Meong Hi; Jung, Hye Lim; Yoo, Keon Hee; Koo, Hong Hoe; Sung, Ki Woong

    2012-01-06

    Peroxisome proliferator-activated receptor γ (PPARγ) regulates multiple signaling pathways, and its agonists induce apoptosis in various cancer cells. However, their role in cell death is unclear. In this study, the relationship between ciglitazone (CGZ) and PPARγ in CGZ-induced cell death was examined. At concentrations of greater than 30 μM, CGZ, a synthetic PPARγ agonist, activated caspase-3 and induced apoptosis in T98G cells. Treatment of T98G cells with less than 30 μM CGZ effectively induced cell death after pretreatment with 30 μM of the PPARγ antagonist GW9662, although GW9662 alone did not induce cell death. This cell death was also observed when cells were co-treated with CGZ and GW9662, but was not observed when cells were treated with CGZ prior to GW9662. In cells in which PPARγ was down-regulated cells by siRNA, lower concentrations of CGZ (death, although higher concentrations of CGZ (≥30 μM) were required to induce cell death in control T98G cells, indicating that CGZ effectively induces cell death in T98G cells independently of PPARγ. Treatment with GW9662 followed by CGZ resulted in a down-regulation of Akt activity and the loss of mitochondrial membrane potential (MMP), which was accompanied by a decrease in Bcl-2 expression and an increase in Bid cleavage. These data suggest that CGZ is capable of inducing apoptotic cell death independently of PPARγ in glioma cells, by down-regulating Akt activity and inducing MMP collapse. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Inhibitor of differentiation 4 (Id4 is a potential tumor suppressor in prostate cancer

    Directory of Open Access Journals (Sweden)

    Carey Jason PW

    2009-06-01

    Full Text Available Abstract Background Inhibitor of differentiation 4 (Id4, a member of the Id gene family is also a dominant negative regulator of basic helix loop helix (bHLH transcription factors. Some of the functions of Id4 appear to be unique as compared to its other family members Id1, Id2 and Id3. Loss of Id4 gene expression in many cancers in association with promoter hypermethylation has led to the proposal that Id4 may act as a tumor suppressor. In this study we provide functional evidence that Id4 indeed acts as a tumor suppressor and is part of a cancer associated epigenetic re-programming. Methods Data mining was used to demonstrate Id4 expression in prostate cancer. Methylation specific polymerase chain reaction (MSP analysis was performed to understand molecular mechanisms associated with Id4 expression in prostate cancer cell lines. The effect of ectopic Id4 expression in DU145 cells was determined by cell cycle analysis (3H thymidine incorporation and FACS, expression of androgen receptor, p53 and cyclin dependent kinase inhibitors p27 and p21 by a combination of RT-PCR, real time-PCR, western blot and immuno-cytochemical analysis. Results Id4 expression was down-regulated in prostate cancer. Id4 expression was also down-regulated in prostate cancer line DU145 due to promoter hyper-methylation. Ectopic Id4 expression in DU145 prostate cancer cell line led to increased apoptosis and decreased cell proliferation due in part by an S-phase arrest. In addition to S-phase arrest, ectopic Id4 expression in PC3 cells also resulted in prolonged G2/M phase. At the molecular level these changes were associated with increased androgen receptor (AR, p21, p27 and p53 expression in DU145 cells. Conclusion The results suggest that Id4 acts directly as a tumor suppressor by influencing a hierarchy of cellular processes at multiple levels that leads to a decreased cell proliferation and change in morphology that is possibly mediated through induction of previously

  19. Methylglyoxal-bis(guanylhydrazone), a polyamine analogue, sensitized γ-radiation-induced cell death in HL-60 leukemia cells Sensitizing effect of MGBG on γ-radiation-induced cell death.

    Science.gov (United States)

    Kim, Jin Sik; Lee, Jin; Chung, Hai Won; Choi, Han; Paik, Sang Gi; Kim, In Gyu

    2006-09-01

    Methylglyoxal-bis(guanylhydrazone) (MGBG), a polyamine analogue, has been known to inhibit the biosynthesis of polyamines, which are important in cell proliferation. We showed that MGBG treatment significantly affected γ-radiation-induced cell cycle transition (G(1)/G(0)→S→G(2)/M) and thus γ-radiation-induced cell death. As determined by micronuclei and comet assay, we showed that it sensitized the cytotoxic effect induced by γ-radiation. One of the reasons is that polyamine depletion by MGBG treatment did not effectively protect against the chemical (OH) or physical damage to DNA caused by γ-radiation. Through in vitro experiment, we confirmed that DNA strand breaks induced by γ-radiation was prevented more effectively in the presence of polyamines (spermine and spermidine) than in the absence of polyamines. MGBG also blocks the cell cycle transition caused by γ-radiation (G(2) arrest), which helps protect cells by allowing time for DNA repair before entry into mitosis or apoptosis, via the down regulation of cyclin D1, which mediates the transition from G(1) to S phase of cell cycle, and ataxia telangiectasia mutated, which is involved in the DNA sensing, repair and cell cycle check point. Therefore, the abrogation of G(2) arrest sensitizes cells to the effect of γ-radiation. As a result, γ-radiation-induced cell death increased by about 2.5-3.0-fold in cells treated with MGBG. However, exogenous spermidine supplement partially relieved this γ-radiation-induced cytotoxicity and cell death. These findings suggest a potentially therapeutic strategy for increasing the cytotoxic efficacy of γ-radiation.

  20. Interplay between autophagy and programmed cell death in mammalian neural stem cells

    Directory of Open Access Journals (Sweden)

    Kyung Min Chung

    2013-08-01

    Full Text Available Mammalian neural stem cells (NSCs are of particular interestbecause of their role in brain development and function. Recentfindings suggest the intimate involvement of programmed celldeath (PCD in the turnover of NSCs. However, the underlyingmechanisms of PCD are largely unknown. Although apoptosis isthe best-defined form of PCD, accumulating evidence hasrevealed a wide spectrum of PCD encompassing apoptosis,autophagic cell death (ACD and necrosis. This mini-reviewaims to illustrate a unique regulation of PCD in NSCs. Theresults of our recent studies on autophagic death of adulthippocampal neural stem (HCN cells are also discussed. HCNcell death following insulin withdrawal clearly provides areliable model that can be used to analyze the molecularmechanisms of ACD in the larger context of PCD. Moreresearch efforts are needed to increase our understanding of themolecular basis of NSC turnover under degenerating conditions,such as aging, stress and neurological diseases. Efforts aimed atprotecting and harnessing endogenous NSCs will offer novelopportunities for the development of new therapeutic strategiesfor neuropathologies. [BMB Reports 2013; 46(8: 383-390

  1. The long non-coding RNA H19-derived miR-675 modulates human gastric cancer cell proliferation by targeting tumor suppressor RUNX1

    International Nuclear Information System (INIS)

    Zhuang, Ming; Gao, Wen; Xu, Jing; Wang, Ping; Shu, Yongqian

    2014-01-01

    Graphical abstract: - Highlights: • H19 regulates gastric cancer cell proliferation phenotype via miR-675. • MiR-675 modulates cell proliferation of gastric cancer cells by targeting tumor suppressor RUNX1. • The H19/miR-675/RUNX1 axis plays an important role in the tumorigenesis of gastric cancer. - Abstract: The lncRNA H19 has been recently shown to be upregulated and play important roles in gastric cancer tumorigenesis. However, the precise molecular mechanism of H19 and its mature product miR-675 in the carcinogenesis of gastric cancer remains unclear. In this study, we found that miR-675 was positively expressed with H19 and was a pivotal mediator in H19-induced gastric cancer cell growth promotion. Subsequently, the tumor suppressor Runt Domain Transcription Factor1 (RUNX1) was confirmed to be a direct target of miR-675 using a luciferase reporter assay and Western blotting analyses. A series of rescue assays indicated that RUNX1 mediated H19/miR-67-induced gastric cancer cell phenotypic changes. Moreover, the inverse relationship between the expression of RUNX1 and H19/miR-675 was also revealed in gastric cancer tissues and gastric cancer cell lines. Taken together, our study demonstrated that the novel pathway H19/miR-675/RUNX1 regulates gastric cancer development and may serve as a potential target for gastric cancer therapy

  2. The Phosphodiesterase 4 Inhibitor Roflumilast Protects against Cigarette Smoke Extract-Induced Mitophagy-Dependent Cell Death in Epithelial Cells.

    Science.gov (United States)

    Kyung, Sun Young; Kim, Yu Jin; Son, Eun Suk; Jeong, Sung Hwan; Park, Jeong Woong

    2018-04-01

    Recent studies show that mitophagy, the autophagy-dependent turnover of mitochondria, mediates pulmonary epithelial cell death in response to cigarette smoke extract (CSE) exposure and contributes to the development of emphysema in vivo during chronic cigarette smoke (CS) exposure, although the underlying mechanisms remain unclear. In this study, we investigated the role of mitophagy in the regulation of CSE-exposed lung bronchial epithelial cell (Beas-2B) death. We also investigated the role of a phosphodiesterase 4 inhibitor, roflumilast, in CSE-induced mitophagy-dependent cell death. Our results demonstrated that CSE induces mitophagy in Beas-2B cells through mitochondrial dysfunction and increased the expression levels of the mitophagy regulator protein, PTEN-induced putative kinase-1 (PINK1), and the mitochondrial fission protein, dynamin-1-like protein (DRP1). CSE-induced epithelial cell death was significantly increased in Beas-2B cells exposed to CSE but was decreased by small interfering RNA-dependent knockdown of DRP1. Treatment with roflumilast in Beas-2B cells inhibited CSE-induced mitochondrial dysfunction and mitophagy by inhibiting the expression of phospho-DRP1 and -PINK1. Roflumilast protected against cell death and increased cell viability, as determined by the lactate dehydrogenase release test and the MTT assay, respectively, in Beas-2B cells exposed to CSE. These findings suggest that roflumilast plays a protective role in CS-induced mitophagy-dependent cell death. Copyright©2018. The Korean Academy of Tuberculosis and Respiratory Diseases.

  3. Tumor induced hepatic myeloid derived suppressor cells can cause moderate liver damage.

    Directory of Open Access Journals (Sweden)

    Tobias Eggert

    Full Text Available Subcutaneous tumors induce the accumulation of myeloid derived suppressor cells (MDSC not only in blood and spleens, but also in livers of these animals. Unexpectedly, we observed a moderate increase in serum transaminases in mice with EL4 subcutaneous tumors, which prompted us to study the relationship of hepatic MDSC accumulation and liver injury. MDSC were the predominant immune cell population expanding in livers of all subcutaneous tumor models investigated (RIL175, B16, EL4, CT26 and BNL, while liver injury was only observed in EL4 and B16 tumor-bearing mice. Elimination of hepatic MDSC in EL4 tumor-bearing mice using low dose 5-fluorouracil (5-FU treatment reversed transaminase elevation and adoptive transfer of hepatic MDSC from B16 tumor-bearing mice caused transaminase elevation indicating a direct MDSC mediated effect. Surprisingly, hepatic MDSC from B16 tumor-bearing mice partially lost their damage-inducing potency when transferred into mice bearing non damage-inducing RIL175 tumors. Furthermore, MDSC expansion and MDSC-mediated liver injury further increased with growing tumor burden and was associated with different cytokines including GM-CSF, VEGF, interleukin-6, CCL2 and KC, depending on the tumor model used. In contrast to previous findings, which have implicated MDSC only in protection from T cell-mediated hepatitis, we show that tumor-induced hepatic MDSC themselves can cause moderate liver damage.

  4. Nitric oxide production is not required for dihydrosphingosine-induced cell death in tobacco BY-2 cells.

    Science.gov (United States)

    Da Silva, Daniel; Lachaud, Christophe; Cotelle, Valérie; Brière, Christian; Grat, Sabine; Mazars, Christian; Thuleau, Patrice

    2011-05-01

    Sphinganine or dihydrosphingosine (d18:0, DHS), one of the most abundant free sphingoid Long Chain Base (LCB) in plants, is known to induce a calcium dependent programmed cell death (PCD) in tobacco BY-2 cells. In addition, we have recently shown that DHS triggers a production of H2O2, via the activation of NADPH oxidase(s). However, this production of H2O2 is not correlated with the DHS-induced cell death but would rather be associated with basal cell defense mechanisms. In the present study, we extend our current knowledge of the DHS signaling pathway, by demonstrating that DHS also promotes a production of nitric oxide (NO) in tobacco BY-2 cells. As for H2O2, this NO production is not necessary for cell death induction. 

  5. Thioredoxin reductase deficiency potentiates oxidative stress, mitochondrial dysfunction and cell death in dopaminergic cells.

    Directory of Open Access Journals (Sweden)

    Pamela Lopert

    Full Text Available Mitochondria are considered major generators of cellular reactive oxygen species (ROS which are implicated in the pathogenesis of neurodegenerative diseases such as Parkinson's disease (PD. We have recently shown that isolated mitochondria consume hydrogen peroxide (H₂O₂ in a substrate- and respiration-dependent manner predominantly via the thioredoxin/peroxiredoxin (Trx/Prx system. The goal of this study was to determine the role of Trx/Prx system in dopaminergic cell death. We asked if pharmacological and lentiviral inhibition of the Trx/Prx system sensitized dopaminergic cells to mitochondrial dysfunction, increased steady-state H₂O₂ levels and death in response to toxicants implicated in PD. Incubation of N27 dopaminergic cells or primary rat mesencephalic cultures with the Trx reductase (TrxR inhibitor auranofin in the presence of sub-toxic concentrations of parkinsonian toxicants paraquat; PQ or 6-hydroxydopamine; 6OHDA (for N27 cells resulted in a synergistic increase in H₂O₂ levels and subsequent cell death. shRNA targeting the mitochondrial thioredoxin reductase (TrxR2 in N27 cells confirmed the effects of pharmacological inhibition. A synergistic decrease in maximal and reserve respiratory capacity was observed in auranofin treated cells and TrxR2 deficient cells following incubation with PQ or 6OHDA. Additionally, TrxR2 deficient cells showed decreased basal mitochondrial oxygen consumption rates. These data demonstrate that inhibition of the mitochondrial Trx/Prx system sensitizes dopaminergic cells to mitochondrial dysfunction, increased steady-state H₂O₂, and cell death. Therefore, in addition to their role in the production of cellular H₂O₂ the mitochondrial Trx/Prx system serve as a major sink for cellular H₂O₂ and its disruption may contribute to dopaminergic pathology associated with PD.

  6. Morphological classification of plant cell deaths

    NARCIS (Netherlands)

    Doorn, van W.G.; Beers, E.P.; Dangl, J.L.; Franklin-Tong, V.E.; Woltering, E.J.

    2011-01-01

    Programmed cell death (PCD) is an integral part of plant development and of responses to abiotic stress or pathogens. Although the morphology of plant PCD is, in some cases, well characterised and molecular mechanisms controlling plant PCD are beginning to emerge, there is still confusion about the

  7. Reasons of reproductive death of mammalian cells

    International Nuclear Information System (INIS)

    Obaturov, G.M.

    1988-01-01

    According to its functional-structural organization the cell is rather a difficult object. It contains many various components, which essentially differ from the another according to their significance for its normal functioning, as well as sizes and number. When analyzing damage different types in cell sensitive target, that is - DNA, the author concludes, that it is most probable, that chromosomal aberrations are, mainly the reasons of cell reproduction death, rather than DNA unrepaired breaks

  8. Using stochastic cell division and death to probe minimal units of cellular replication

    Science.gov (United States)

    Chib, Savita; Das, Suman; Venkatesan, Soumya; Sai Narain Seshasayee, Aswin; Thattai, Mukund

    2018-03-01

    The invariant cell initiation mass measured in bacterial growth experiments has been interpreted as a minimal unit of cellular replication. Here we argue that the existence of such minimal units induces a coupling between the rates of stochastic cell division and death. To probe this coupling we tracked live and dead cells in Escherichia coli populations treated with a ribosome-targeting antibiotic. We find that the growth exponent from macroscopic cell growth or decay measurements can be represented as the difference of microscopic first-order cell division and death rates. The boundary between cell growth and decay, at which the number of live cells remains constant over time, occurs at the minimal inhibitory concentration (MIC) of the antibiotic. This state appears macroscopically static but is microscopically dynamic: division and death rates exactly cancel at MIC but each is remarkably high, reaching 60% of the antibiotic-free division rate. A stochastic model of cells as collections of minimal replicating units we term ‘widgets’ reproduces both steady-state and transient features of our experiments. Sub-cellular fluctuations of widget numbers stochastically drive each new daughter cell to one of two alternate fates, division or death. First-order division or death rates emerge as eigenvalues of a stationary Markov process, and can be expressed in terms of the widget’s molecular properties. High division and death rates at MIC arise due to low mean and high relative fluctuations of widget number. Isolating cells at the threshold of irreversible death might allow molecular characterization of this minimal replication unit.

  9. LARG at chromosome 11q23 has functional characteristics of a tumor suppressor in human breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Danny C.T.; Rudduck, Christina; Chin, Koei; Kuo, Wen-Lin; Lie, Daniel K.H.; Chua, Constance L.M.; Wong, Chow Yin; Hong, Ga Sze; Gray, Joe; Lee, Ann S.G.

    2008-05-06

    Deletion of 11q23-q24 is frequent in a diverse variety of malignancies, including breast and colorectal carcinoma, implicating the presence of a tumor suppressor gene at that chromosomal region. We show here that LARG, from 11q23, has functional characteristics of a tumor suppressor. We examined a 6-Mb region on 11q23 by high-resolution deletion mapping, utilizing both loss of heterozygosity (LOH) analysis and microarray comparative genomic hybridization (CGH). LARG (also called ARHGEF12), identified from the analyzed region, was underexpressed in 34% of primary breast carcinomas and 80% of breast cancer cell lines including the MCF-7 line. Multiplex ligation-dependent probe amplification on 30 primary breast cancers and six breast cancer cell lines showed that LARG had the highest frequency of deletion compared to the BCSC-1 and TSLC1 genes, two known candidate tumor suppressor genes from 11q. In vitro analysis of breast cancer cell lines that underexpress LARG showed that LARG could be reactivated by trichostatin A, a histone deacetylase inhibitor, but not by 5-Aza-2{prime}-deoxycytidine, a demethylating agent. Bisulfite sequencing and quantitative high-throughput analysis of DNA methylation confirmed the lack of CpG island methylation in LARG in breast cancer. Restoration of LARG expression in MCF-7 cells by stable transfection resulted in reduced proliferation and colony formation, suggesting that LARG has functional characteristics of a tumor suppressor gene.

  10. Differential expression of the klf6 tumor suppressor gene upon cell damaging treatments in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Gehrau, Ricardo C.; D' Astolfo, Diego S.; Andreoli, Veronica [Centro de Investigaciones en Bioquimica Clinica e Inmunologia (CIBICI-CONICET), Departamento de Bioquimica Clinica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Bocco, Jose L., E-mail: jbocco@fcq.unc.edu.ar [Centro de Investigaciones en Bioquimica Clinica e Inmunologia (CIBICI-CONICET), Departamento de Bioquimica Clinica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Koritschoner, Nicolas P. [Centro de Investigaciones en Bioquimica Clinica e Inmunologia (CIBICI-CONICET), Departamento de Bioquimica Clinica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2011-02-10

    The mammalian Krueppel-like factor 6 (KLF6) is involved in critical roles such as growth-related signal transduction, cell proliferation and differentiation, development, apoptosis and angiogenesis. Also, KLF6 appears to be an emerging key factor during cancer development and progression. Its expression is thoroughly regulated by several cell-damaging stimuli. DNA damaging agents at lethal concentrations induce a p53-independent down-regulation of the klf6 gene. To investigate the impact of external stimuli on human klf6 gene expression, its mRNA level was analyzed using a cancer cell line profiling array system, consisting in an assortment of immobilized cDNAs from multiple cell lines treated with several cell-damaging agents at growth inhibitory concentrations (IC{sub 50}). Cell-damaging agents affected the klf6 expression in 62% of the cDNA samples, though the expression pattern was not dependent on the cell origin type. Interestingly, significant differences (p < 0.0001) in KLF6 mRNA levels were observed depending on the cellular p53 status upon cell damage. KLF6 expression was significantly increased in 63% of p53-deficient cells (122/195). Conversely, KLF6 mRNA level decreased nearly 4 fold in more than 70% of p53+/+ cells. In addition, klf6 gene promoter activity was down-regulated by DNA damaging agents in cells expressing the functional p53 protein whereas it was moderately increased in the absence of functional p53. Consistent results were obtained for the endogenous KLF6 protein level. Results indicate that human klf6 gene expression is responsive to external cell damage mediated by IC{sub 50} concentrations of physical and chemical stimuli in a p53-dependent manner. Most of these agents are frequently used in cancer therapy. Induction of klf6 expression in the absence of functional p53 directly correlates with cell death triggered by these compounds, whereas it is down-regulated in p53+/+ cells. Hence, klf6 expression level could represent a valuable

  11. Blocking CD147 induces cell death in cancer cells through impairment of glycolytic energy metabolism

    International Nuclear Information System (INIS)

    Baba, Miyako; Inoue, Masahiro; Itoh, Kazuyuki; Nishizawa, Yasuko

    2008-01-01

    CD147 is a multifunctional transmembrane protein and promotes cancer progression. We found that the anti-human CD147 mouse monoclonal antibody MEM-M6/1 strongly induces necrosis-like cell death in LoVo, HT-29, WiDr, and SW620 colon cancer cells and A2058 melanoma cells, but not in WI-38 and TIG-113 normal fibroblasts. Silencing or overexpression of CD147 in LoVo cells enhanced or decreased the MEM-M6/1 induced cell death, respectively. CD147 is known to form complex with proton-linked monocarboxylate transporters (MCTs), which is critical for lactate transport and intracellular pH (pHi) homeostasis. In LoVo cells, CD147 and MCT-1 co-localized on the cell surface, and MEM-M6/1 inhibited the association of these molecules. MEM-M6/1 inhibited lactate uptake, lactate release, and reduced pHi. Further, the induction of acidification was parallel to the decrease of the glycolytic flux and intracellular ATP levels. These effects were not found in the normal fibroblasts. As cancer cells depend on glycolysis for their energy production, CD147 inhibition might induce cell death specific to cancer cells

  12. Death receptor pathways mediate targeted and non-targeted effects of ionizing radiations in breast cancer cells

    International Nuclear Information System (INIS)

    Luce, A.; Courtin, A.; Levalois, C.; Altmeyer-Morel, S.; Chevillard, S.; Lebeau, J.; Romeo, P.H.

    2009-01-01

    Delayed cell death by mitotic catastrophe is a frequent mode of solid tumor cell death after γ-irradiation, a widely used treatment of cancer. Whereas the mechanisms that underlie the early γ-irradiation-induced cell death are well documented, those that drive the delayed cell death are largely unknown. Here we show that the Fas, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and tumor necrosis factor (TNF)-α death receptor pathways mediate the delayed cell death observed after γ-irradiation of breast cancer cells. Early after irradiation, we observe the increased expression of Fas, TRAIL-R and TNF-R that first sensitizes cells to apoptosis. Later, the increased expression of FasL, TRAIL and TNF-α permit the apoptosis engagement linked to mitotic catastrophe. Treatments with TNF-α, TRAIL or anti-Fas antibody, early after radiation exposure, induce apoptosis, whereas the neutralization of the three death receptors pathways impairs the delayed cell death. We also show for the first time that irradiated breast cancer cells excrete soluble forms of the three ligands that can induce the death of sensitive bystander cells. Overall, these results define the molecular basis of the delayed cell death of irradiated cancer cells and identify the death receptors pathways as crucial actors in apoptosis induced by targeted as well as non-targeted effects of ionizing radiation. (authors)

  13. Early death during chemotherapy in patients with small-cell lung cancer

    DEFF Research Database (Denmark)

    Lassen, U N; Osterlind, K; Hirsch, F R

    1999-01-01

    Based on an increased frequency of early death (death within the first treatment cycle) in our two latest randomized trials of combination chemotherapy in small-cell lung cancer (SCLC), we wanted to identify patients at risk of early non-toxic death (ENTD) and early toxic death (ETD). Data were s...

  14. Canthin-6-one induces cell death, cell cycle arrest and differentiation in human myeloid leukemia cells.

    Science.gov (United States)

    Vieira Torquato, Heron F; Ribeiro-Filho, Antonio C; Buri, Marcus V; Araújo Júnior, Roberto T; Pimenta, Renata; de Oliveira, José Salvador R; Filho, Valdir C; Macho, Antonio; Paredes-Gamero, Edgar J; de Oliveira Martins, Domingos T

    2017-04-01

    Canthin-6-one is a natural product isolated from various plant genera and from fungi with potential antitumor activity. In the present study, we evaluate the antitumor effects of canthin-6-one in human myeloid leukemia lineages. Kasumi-1 lineage was used as a model for acute myeloid leukemia. Cells were treated with canthin-6-one and cell death, cell cycle and differentiation were evaluated in both total cells (Lin + ) and leukemia stem cell population (CD34 + CD38 - Lin -/low ). Among the human lineages tested, Kasumi-1 was the most sensitive to canthin-6-one. Canthin-6-one induced cell death with apoptotic (caspase activation, decrease of mitochondrial potential) and necrotic (lysosomal permeabilization, double labeling of annexin V/propidium iodide) characteristics. Moreover, canthin-6-one induced cell cycle arrest at G 0 /G 1 (7μM) and G 2 (45μM) evidenced by DNA content, BrdU incorporation and cyclin B1/histone 3 quantification. Canthin-6-one also promoted differentiation of Kasumi-1, evidenced by an increase in the expression of myeloid markers (CD11b and CD15) and the transcription factor PU.1. Furthermore, a reduction of the leukemic stem cell population and clonogenic capability of stem cells were observed. These results show that canthin-6-one can affect Kasumi-1 cells by promoting cell death, cell cycle arrest and cell differentiation depending on concentration used. Canthin-6-one presents an interesting cytotoxic activity against leukemic cells and represents a promising scaffold for the development of molecules for anti-leukemic applications, especially by its anti-leukemic stem cell activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Loss of Mitochondrial Tumor Suppressor Genes Expression Is Associated with Unfavorable Clinical Outcome in Head and Neck Squamous Cell Carcinoma: Data from Retrospective Study.

    Directory of Open Access Journals (Sweden)

    Ishrat Mahjabeen

    Full Text Available Mitochondrial genes play important roles in cellular energy metabolism, free radical generation, and apoptosis. Dysregulation of these genes have long been suspected to contribute to the generation of reactive oxygen species (ROS, increased proliferation and progression of cancer. A family of orthologues of yeast silent information regulator 3 (SIRT3, 4 (SIRT4 and mitochondrial tumor suppressor 1 (MTUS1 are important mitochondrial tumor suppressor genes which play an important role in the progression of multiple cancers. However, their role in the development of oxidative stress, enhanced proliferation and progression of head and neck squamous cell carcinoma (HNSCC has not yet been studied. In this study we aimed to test the association between reduced mitochondrial tumor suppressor genes' activities and enhancement in tissue oxidative stress and cell proliferation in HNSCC cases. The expression of mitochondrial tumor suppressor genes (SIRT3, SIRT4 and MTUS1, mitochondrial DNA repair gene (OGG1-2a and a proliferation marker (Ki-67 was studied in a study cohort of 120 HNSCC patients and controls with reverse transcriptase polymerase chain reaction (RT-PCR and real-time PCR (qPCR in order to determine the potential prognostic significance of these genes. A statistically significant downregulation of SIRT3 (p<0.001, SIRT4 (p<0.0001, MTUS1 (p<0.002 and OGG1 (p<0.0001 was observed in HNSCC compared to control samples. Ki-67 was also overexpressed (p<0.0001 in HNSCC versus control samples. Additionally, to explore gene-gene relationship, we observed a positive spearmen correlation between SIRT3 versus SIRT4 (r = 0.523***, p<0.0001, SIRT3 versus MTUS1 (r = 0.273***, p<0.001, SIRT3 versus OGG1-2a (r = 0.213*, p<0.03, SIRT4 versus OGG1 (r = 0.338***, p<0.0001 and MTUS1 versus OGG1-2a (r = 0.215*, p<0.03 in HNSCC cases. A negative spearman correlation was observed between OGG1 versus Ki-67 (r = -0.224**, p<0.01 and OGG1-2a versus Ki-67 (r = -0.224**, p<0

  16. Effect of duct shape, Mach number, and lining construction on measured suppressor attenuation and comparison with theory

    Science.gov (United States)

    Olsen, W. A.; Krejsa, E. A.; Coats, J. W.

    1972-01-01

    Noise attenuation was measured for several types of cylindrical suppressors that use a duct lining composed of honeycomb cells covered with a perforated plate. The experimental technique used gave attenuation data that were repeatable and free of noise floors and other sources of error. The suppressor length, the effective acoustic diameter, suppressor shape and flow velocity were varied. The agreement among the attenuation data and two widely used analytical models was generally satisfactory. Changes were also made in the construction of the acoustic lining to measure their effect on attenuation. One of these produced a very broadband muffler.

  17. Coniferyl aldehyde attenuates radiation enteropathy by inhibiting cell death and promoting endothelial cell function.

    Science.gov (United States)

    Jeong, Ye-Ji; Jung, Myung Gu; Son, Yeonghoon; Jang, Jun-Ho; Lee, Yoon-Jin; Kim, Sung-Ho; Ko, Young-Gyo; Lee, Yun-Sil; Lee, Hae-June

    2015-01-01

    Radiation enteropathy is a common complication in cancer patients. The aim of this study was to investigate whether radiation-induced intestinal injury could be alleviated by coniferyl aldehyde (CA), an HSF1-inducing agent that increases cellular HSP70 expression. We systemically administered CA to mice with radiation enteropathy following abdominal irradiation (IR) to demonstrate the protective effects of CA against radiation-induced gastrointestinal injury. CA clearly alleviated acute radiation-induced intestinal damage, as reflected by the histopathological data and it also attenuated sub-acute enteritis. CA prevented intestinal crypt cell death and protected the microvasculature in the lamina propria during the acute and sub-acute phases of damage. CA induced HSF1 and HSP70 expression in both intestinal epithelial cells and endothelial cells in vitro. Additionally, CA protected against not only the apoptotic cell death of both endothelial and epithelial cells but also the loss of endothelial cell function following IR, indicating that CA has beneficial effects on the intestine. Our results provide novel insight into the effects of CA and suggest its role as a therapeutic candidate for radiation-induced enteropathy due to its ability to promote rapid re-proliferation of the intestinal epithelium by the synergic effects of the inhibition of cell death and the promotion of endothelial cell function.

  18. Cell death in Tetrahymena thermophila: new observations on culture conditions.

    Science.gov (United States)

    Christensen, S T; Sørensen, H; Beyer, N H; Kristiansen, K; Rasmussen, L; Rasmussen, M I

    2001-01-01

    We previously suggested that the cell fate of the protozoan ciliate, Tetrahymena thermophila, effectively relates to a quorum-sensing mechanism where cell-released factors support cell survival and proliferation. The cells have to be present above a critical initial density in a chemically defined nutrient medium in order to release a sufficient level of these factors to allow a new colony to flourish. At a relatively high rate of metabolism and/or macromolecular synthesis and below this critical density, cells began to die abruptly within 30 min of inoculation, and this death took the form of an explosive disintegration lasting less than 50 milliseconds. The cells died at any location in the culture, and the frequency of cell death was always lower in well-filled vials than those with medium/air interface. Cell death was inhibited by the addition of Actinomycin D or through modifications of the culture conditions either by reducing the oxygen tension or by decreasing the temperature of the growth medium. In addition, plastic caps in well-filled vials release substances, which promote cell survival. The fate of low-density cultures is related to certain 'physical' conditions, in addition to the availability of oxygen within closed culture systems. Copyright 2001 Academic Press.

  19. Megasporogenesis and programmed cell death in Tillandsia (Bromeliaceae).

    Science.gov (United States)

    Papini, Alessio; Mosti, Stefano; Milocani, Eva; Tani, Gabriele; Di Falco, Pietro; Brighigna, Luigi

    2011-10-01

    The degeneration of three of four meiotic products is a very common process in the female gender of oogamous eukaryotes. In Tillandsia (and many other angiosperms), the surviving megaspore has a callose-free wall in chalazal position while the other three megaspores are completely embedded in callose. Therefore, nutrients and signals can reach more easily the functional megaspore from the nucellus through the chalazal pole with respect to the other megaspores. The abortion of three of four megaspores was already recognized as the result of a programmed cell death (PCD) process. We investigated the process to understand the modality of this specific type of PCD and its relationship to the asymmetric callose deposition around the tetrad. The decision on which of the four megaspores will be the supernumerary megaspores in angiosperms, and hence destined to undergo programmed cell death, appears to be linked to the callose layer deposition around the tetrad. During supernumerary megaspores degeneration, events leading to the deletion of the cells do not appear to belong to a single type of cell death. The first morphological signs are typical of autophagy, including the formation of autophagosomes. The TUNEL positivity and a change in morphology of mitochondria and chloroplasts indicate the passage to an apoptotic-like PCD phase, while the cellular remnants undergo a final process resembling at least partially (ER swelling) necrotic morphological syndromes, eventually leading to a mainly lipidic cell corpse still separated from the functional megaspore by a callose layer.

  20. Programmed cell death and cell extrusion in rat duodenum

    DEFF Research Database (Denmark)

    Schauser, Kirsten; Larsson, Lars-Inge

    2005-01-01

    The small intestinal epithelium is continously renewed through a balance between cell division and cell loss. How this balance is achieved is uncertain. Thus, it is unknown to what extent programmed cell death (PCD) contributes to intestinal epithelial cell loss. We have used a battery...... of techniques detecting the events associated with PCD in order to better understand its role in the turnover of the intestinal epithelium, including modified double- and triple-staining techniques for simultaneously detecting multiple markers of PCD in individual cells. Only a partial correlation between TUNEL...... positivity for DNA fragmentation, c-jun phosphorylation on serine-63, positivity for activated caspase-3 and apoptotic morphology was observed. Our results show that DNA fragmentation does not invariable correlate to activation of caspase-3. Moreover, many cells were found to activate caspase-3 early...

  1. Programmed Cell Death and Postharvest Deterioration of Horticultural Produce

    NARCIS (Netherlands)

    Woltering, E.J.; Iakimova, E.T.

    2010-01-01

    Programmed cell death (PCD) is a process where cells or tissues are broken down in an orderly and predictable manner, whereby nutrients are re-used by other cells, tissues or plant parts. The process of (petal) senescence shows many similarities to autophagic PCD in animal cells including a massive

  2. miR-199a-3p displays tumor suppressor functions in papillary thyroid carcinoma.

    Science.gov (United States)

    Minna, Emanuela; Romeo, Paola; De Cecco, Loris; Dugo, Matteo; Cassinelli, Giuliana; Pilotti, Silvana; Degl'Innocenti, Debora; Lanzi, Cinzia; Casalini, Patrizia; Pierotti, Marco A; Greco, Angela; Borrello, Maria Grazia

    2014-05-15

    Thyroid cancer incidence is rapidly increasing. Papillary Thyroid Carcinoma (PTC), the most frequent hystotype, usually displays good prognosis, but no effective therapeutic options are available for the fraction of progressive PTC patients. BRAF and RET/PTC are the most frequent driving genetic lesions identified in PTC. We developed two complementary in vitro models based on RET/PTC1 oncogene, starting from the hypothesis that miRNAs modulated by a driving PTC-oncogene are likely to have a role in thyroid neoplastic processes. Through this strategy, we identified a panel of deregulated miRNAs. Among these we focused on miR-199a-3p and showed its under-expression in PTC specimens and cell lines. We demonstrated that miR-199a-3p restoration in PTC cells reduces MET and mTOR protein levels, impairs migration and proliferation and, more interesting, induces lethality through an unusual form of cell death similar to methuosis, caused by macropinocytosis dysregulation. Silencing MET or mTOR, both involved in survival pathways, does not recapitulate miR-199a-3p-induced cell lethality, thus suggesting that the cooperative regulation of multiple gene targets is necessary. Integrated analysis of miR-199a-3p targets unveils interesting networks including HGF and macropinocytosis pathways. Overall our results indicate miR-199a-3p as a tumor suppressor miRNA in PTC.

  3. Ezrin dephosphorylation/downregulation contributes to ursolic acid-mediated cell death in human leukemia cells

    International Nuclear Information System (INIS)

    Li, G; Zhou, T; Liu, L; Chen, J; Zhao, Z; Peng, Y; Li, P; Gao, N

    2013-01-01

    Ezrin links the actin filaments with the cell membrane and has a functional role in the apoptotic process. It appears clear that ezrin is directly associated with Fas, leading to activation of caspase cascade and cell death. However, the exact role of ezrin in ursolic acid (UA)-induced apoptosis remains unclear. In this study, we show for the first time that UA induces apoptosis in both transformed and primary leukemia cells through dephosphorylation/downregulation of ezrin, association and polarized colocalization of Fas and ezrin, as well as formation of death-inducing signaling complex. These events are dependent on Rho-ROCK1 signaling pathway. Knockdown of ezrin enhanced cell death mediated by UA, whereas overexpression of ezrin attenuated UA-induced apoptosis. Our in vivo study also showed that UA-mediated inhibition of tumor growth of mouse leukemia xenograft model is in association with the dephosphorylation/downregulation of ezrin. Such findings suggest that the cytoskeletal protein ezrin may represent an attractive target for UA-mediated lethality in human leukemia cells

  4. Networked T cell death following macrophage infection by Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Stephen H-F Macdonald

    Full Text Available BACKGROUND: Depletion of T cells following infection by Mycobacterium tuberculosis (Mtb impairs disease resolution, and interferes with clinical test performance that relies on cell-mediated immunity. A number of mechanisms contribute to this T cell suppression, such as activation-induced death and trafficking of T cells out of the peripheral circulation and into the diseased lungs. The extent to which Mtb infection of human macrophages affects T cell viability however, is not well characterised. METHODOLOGY/PRINCIPAL FINDINGS: We found that lymphopenia (<1.5 × 10(9 cells/l was prevalent among culture-positive tuberculosis patients, and lymphocyte counts significantly improved post-therapy. We previously reported that Mtb-infected human macrophages resulted in death of infected and uninfected bystander macrophages. In the current study, we sought to examine the influence of infected human alveolar macrophages on T cells. We infected primary human alveolar macrophages (the primary host cell for Mtb or PMA-differentiated THP-1 cells with Mtb H37Ra, then prepared cell-free supernatants. The supernatants of Mtb-infected macrophages caused dose-dependent, caspase-dependent, T cell apoptosis. This toxic effect of infected macrophage secreted factors did not require TNF-α or Fas. The supernatant cytotoxic signal(s were heat-labile and greater than 50 kDa in molecular size. Although ESAT-6 was toxic to T cells, other Mtb-secreted factors tested did not influence T cell viability; nor did macrophage-free Mtb bacilli or broth from Mtb cultures. Furthermore, supernatants from Mycobacterium bovis Bacille de Calmette et Guerin (BCG- infected macrophages also elicited T cell death suggesting that ESAT-6 itself, although cytotoxic, was not the principal mediator of T cell death in our system. CONCLUSIONS: Mtb-Infected macrophages secrete heat-labile factors that are toxic to T cells, and may contribute to the immunosuppression seen in tuberculosis as well as

  5. Hsa-let-7a functions as a tumor suppressor in renal cell carcinoma cell lines by targeting c-myc

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongchao; Yin, Bingde; Zhang, Changcun; Zhou, Libin [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China); Fan, Jie, E-mail: jief67@sina.com [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer This study is the first to test the let-7a/c-myc loop in renal cell carcinoma cell lines. Black-Right-Pointing-Pointer Let-7a down-regulated c-myc in three renal cell carcinoma cell lines. Black-Right-Pointing-Pointer c-myc target genes were down-regulated because of the let-7a-mediated down-regulation of c-myc. Black-Right-Pointing-Pointer The let-7a/c-myc loop has a significant function in renal cell carcinoma cell lines. -- Abstract: Widespread functions of the c-myc pathway play a crucial role in renal cell carcinoma (RCC) carcinogenesis. Thus, we evaluated the connection between proto-oncogenic c-myc and anti-neoplastic hsa-let-7a (let-7a) in RCC cell lines. The levels of c-myc and let-7a in 3 RCC cell lines (769P, Caki-1 and 786O) were measured after transfecting the cells with let-7a mimics or a negative control. The change in c-myc protein level was confirmed by Western blot. The anti-neoplastic function of let-7a was evaluated using cell counting kit-8 (CCK-8) for proliferation analysis and cell flow cytometry for cell cycle analysis. The changes of downstream targets of c-myc were measured using reverse transcription quantitative real-time PCR (qRT-PCR). Our results suggest for the first time that let-7a acts as a tumor suppressor in RCC cell lines by down-regulating c-myc and c-myc target genes such as proliferating cell nuclear antigen (PCNA), cyclin D1 (CCND1) and the miR17-92 cluster, which is accompanied by proliferation inhibition and cell cycle arrest.

  6. Fas/Fas ligand regulation mediates cell death in human Ewing's sarcoma cells treated with melatonin

    Science.gov (United States)

    García-Santos, G; Martin, V; Rodríguez-Blanco, J; Herrera, F; Casado-Zapico, S; Sánchez-Sánchez, A M; Antolín, I; Rodríguez, C

    2012-01-01

    Background: Despite recent advances in cancer therapy, the 5-year survival rate for Ewing's sarcoma is still very low, and new therapeutic approaches are necessary. It was found previously that melatonin induces cell death in the Ewing's sarcoma cell line, SK-N-MC, by activating the extrinsic apoptotic pathway. Methods: Melatonin actions were analysed by metabolic viability/survival cell assays, flow cytometry, quantitative PCR for mRNA expression, western blot for protein activation/expression and electrophoretic mobility shift assay for transcription factor activation. Results: Melatonin increases the expression of Fas and its ligand Fas L, this increase being responsible for cell death induced by the indolamine. Melatonin also produces a transient increase in intracellular oxidants and activation of the redox-regulated transcription factor Nuclear factor-kappaB. Inhibition of such activation prevents cell death and Fas/Fas L upregulation. Cytotoxic effect and Fas/Fas L regulation occur in all Ewing's cell lines studied, and do not occur in the other tumour cell lines studied where melatonin does not induce cell death. Conclusion: Our data offers new insights in the study of alternative therapeutic strategies in the treatment of Ewing's sarcoma. Further attention deserves to be given to the differences in the cellular biology of sensitive tumours that could explain the cytotoxic effect of melatonin and the increase in the level of free radicals caused by this molecule, in particular cancer types. PMID:22382690

  7. Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Kito, Hiroaki [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Yamazaki, Daiju [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ohya, Susumu; Yamamura, Hisao [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

    2011-07-29

    Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  8. Activation of intracellular angiotensin AT2 receptors induces rapid cell death in human uterine leiomyosarcoma cells

    DEFF Research Database (Denmark)

    Zhao, Yi; Lützen, Ulf; Fritsch, Jürgen

    2015-01-01

    The presence of AT2 receptors in mitochondria and their role in NO generation and cell aging were recently demonstrated in various human and mouse non-tumour cells. We investigated the intracellular distribution of AT2 receptors including their presence in mitochondria and the role in the induction...... agonist, Compound 21 (C21) penetrates the cell membrane of quiescent SK-UT-1 cells, activates intracellular AT2 receptors and induces rapid cell death; approximately 70% of cells died within 24 h. The cells, which escaped from the cell death, displayed activation of the mitochondrial apoptotic pathway, i...

  9. An Ursolic Acid Derived Small Molecule Triggers Cancer Cell Death through Hyperstimulation of Macropinocytosis.

    Science.gov (United States)

    Sun, Lin; Li, Bin; Su, Xiaohui; Chen, Ge; Li, Yaqin; Yu, Linqian; Li, Li; Wei, Wanguo

    2017-08-10

    Macropinocytosis is a transient endocytosis that internalizes extracellular fluid and particles into vacuoles. Recent studies suggest that hyperstimulation of macropinocytosis can induce a novel nonapoptotic cell death, methuosis. In this report, we describe the identification of an ursolic acid derived small molecule (compound 17), which induces cancer cell death through hyperstimulation of macropinocytosis. 17 causes the accumulation of vacuoles derived from macropinosomes based on transmission electron microscopy, time-lapse microscopy, and labeling with extracellular fluid phase tracers. The vacuoles induced by 17 separate from other cytoplasmic compartments but acquire some characteristics of late endosomes and lysosomes. Inhibiting hyperstimulation of macropinocytosis with the specific inhibitor amiloride blocks cell death, implicating that 17 leads to cell death via macropinocytosis, which is coincident with methuosis. Our results uncovered a novel cell death pathway involved in the activity of 17, which may provide a basis for further development of natural-product-derived scaffolds for drugs that trigger cancer cell death by methuosis.

  10. Cell death induced by taxanes in sensitive and resistant breast cancer cells

    Czech Academy of Sciences Publication Activity Database

    Ehrlichová, Marie; Truksa, Jaroslav; Naďová, Zuzana; Gut, I.; Kovář, Jan

    2004-01-01

    Roč. 37, č. 2 (2004), s. 120-121 ISSN 0960-7722. [Meeting of the European study group for cell proliferation /26./. Praha, 13.05.2004-16.05.2004] R&D Projects: GA MZd NL6715 Keywords : breast cancer cells * cell death * taxanes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.907, year: 2004

  11. Emerging differential roles of the pRb tumor suppressor in trichodysplasia spinulosa-associated polyomavirus and Merkel cell polyomavirus pathogeneses.

    Science.gov (United States)

    Wu, Julie H; Simonette, Rebecca A; Nguyen, Harrison P; Doan, Hung Q; Rady, Peter L; Tyring, Stephen K

    2016-03-01

    Merkel cell carcinoma (MCC) and trichodysplasia spinulosa (TS) are two proliferative cutaneous diseases caused by the Merkel cell polyomavirus (MCPyV) and trichodysplasia spinulosa-associated polyomavirus (TSPyV) respectively. Recently, studies have elucidated a key role of the small tumor (sT) antigen in the proliferative pathogenic mechanisms of MCPyV and likely TSPyV. While both sT antigens have demonstrated a capacity in regulating cellular pathways, it remains unknown whether MCPyV and TSPyV sT antigens contribute similarly or differentially to cell proliferation. The present study aims to explore the proliferative potential of MCPyV and TSPyV sT antigens by investigating their regulatory effects on the retinoblastoma protein (pRb) tumor suppressor. Inducible cell lines expressing MCPyV sT or TSPyV sT were created using a lentiviral packaging system. Cellular proteins were extracted and subjected to SDS-PAGE followed by Western blot detection and densitometric analysis. Expression of TSPyV sT markedly enhanced the phosphorylation of pRb in Western blot experiments. In contrast, expression of MCPyV sT did not alter pRb phosphorylation under the same experimental conditions. Densitometric analysis revealed that TSPyV sT antigen expression nearly doubled the ratio of phosphorylated to total pRb (P<0.001, Student's T-test), while MCPyV sT antigen expression did not cause significant change in pRb phosphorylation status. Given that hyperphosphorylation of pRb is associated with dysregulation of the cell cycle, S-phase induction, and increased cell proliferation, our findings support an important role of TSPyV-mediated pRb deactivation in the development of TS. The observation that the pRb tumor suppressor is inactivated by TSPyV sT but not MCPyV sT provides further insights into the distinct pathobiological mechanisms of MCC and TS. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Identification of a third protein 4.1 tumor suppressor, protein 4.1R, in meningioma pathogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Robb, Victoria A.; Li, Wen; Gascard, Philippe; Perry, Arie; Mohandas, Narla; Gutmann, David H.

    2003-06-11

    Meningiomas are common tumors of the central nervous system, however, the mechanisms under lying their pathogenesis are largely undefined. Two members of the Protein 4.1 super family, the neuro fibromatosis 2 (NF2) gene product (merlin/schwannomin) and Protein 4.1B have been implicated as meningioma tumor suppressors. In this report, we demonstrate that another Protein 4.1 family member, Protein 4.1R, also functions as a meningioma tumor suppressor. Based on the assignment of the Protein 4.1R gene to chromosome 1p32-36, a common region of deletion observed in meningiomas, we analyzed Protein 4.1R expression in meningioma cell lines and surgical tumor specimens. We observed loss of Protein 4.1R protein expression in two meningioma cell lines (IOMM-Lee, CH157-MN) by Western blotting as well as in 6 of 15 sporadic meningioma as by immuno histo chemistry (IHC). Analysis of a subset of these sporadic meningiomas by fluorescent in situ hybridization (FISH) with a Protein 4.1R specific probe demonstrated 100 percent concordance with the IHC results. In support of a meningioma tumor suppressor function, over expression of Protein 4.1R resulted in suppression of IOMM-Lee and CH157MN cell proliferation. Similar to the Protein 4.1B and merlin meningioma tumor suppressors, Protein 4.1R localization in the membrane fraction increased significantly under conditions of growth arrest in vitro. Lastly, Protein 4.1R interacted with some known merlin/Protein 4.1B interactors such as CD44 and bII-spectrin, but did not associate with the Protein 4.1B interactors 14-3-3 and PRMT3 or the merlin binding proteins SCHIP-1 and HRS. Collectively, these results suggest that Protein 4.1R functions as an important tumor suppressor important in the molecular pathogenesis of meningioma.

  13. TP508 accelerates fracture repair by promoting cell growth over cell death

    International Nuclear Information System (INIS)

    Li Xinmin; Wang Hali; Touma, Edward; Qi Yuchen; Rousseau, Emma; Quigg, Richard J.; Ryaby, James T.

    2007-01-01

    TP508 is a synthetic 23-amino acid peptide representing a receptor-binding domain of human thrombin. We have previously shown that a single injection of TP508 accelerates fracture healing in a rat femoral fracture model. To understand how TP508 acts at the protein level during fracture healing, we compared the translational profiles between saline-control and fractured femur at six time points after TP508 treatment using the second generation of BD Clontech TM Antibody Microarray. Here, we demonstrate that TP508 accelerates fracture healing by modulating expression levels of proteins primarily involved in the functional categories of cell cycle, cellular growth and proliferation, and cell death. The majority of those proteins are physically interrelated and functionally overlapped. The action of those proteins is highlighted by a central theme of promoting cell growth via balance of cell survival over cell death signals. This appears to occur through the stimulation of several bone healing pathways including cell cycle-G1/S checkpoint regulation, apoptosis, JAK/STAT, NF-κB, PDGF, PI3K/AKT, PTEN, and ERK/MAPK

  14. Withaferin A Induces Cell Death Selectively in Androgen-Independent Prostate Cancer Cells but Not in Normal Fibroblast Cells.

    Directory of Open Access Journals (Sweden)

    Yukihiro Nishikawa

    Full Text Available Withaferin A (WA, a major bioactive component of the Indian herb Withania somnifera, induces cell death (apoptosis/necrosis in multiple types of tumor cells, but the molecular mechanism underlying this cytotoxicity remains elusive. We report here that 2 μM WA induced cell death selectively in androgen-insensitive PC-3 and DU-145 prostate adenocarcinoma cells, whereas its toxicity was less severe in androgen-sensitive LNCaP prostate adenocarcinoma cells and normal human fibroblasts (TIG-1 and KD. WA also killed PC-3 cells in spheroid-forming medium. DNA microarray analysis revealed that WA significantly increased mRNA levels of c-Fos and 11 heat-shock proteins (HSPs in PC-3 and DU-145, but not in LNCaP and TIG-1. Western analysis revealed increased expression of c-Fos and reduced expression of the anti-apoptotic protein c-FLIP(L. Expression of HSPs such as HSPA6 and Hsp70 was conspicuously elevated; however, because siRNA-mediated depletion of HSF-1, an HSP-inducing transcription factor, reduced PC-3 cell viability, it is likely that these heat-shock genes were involved in protecting against cell death. Moreover, WA induced generation of reactive oxygen species (ROS in PC-3 and DU-145, but not in normal fibroblasts. Immunocytochemistry and immuno-electron microscopy revealed that WA disrupted the vimentin cytoskeleton, possibly inducing the ROS generation, c-Fos expression and c-FLIP(L suppression. These observations suggest that multiple events followed by disruption of the vimentin cytoskeleton play pivotal roles in WA-mediated cell death.

  15. Tumor suppressor BLU inhibits proliferation of nasopharyngeal carcinoma cells by regulation of cell cycle, c-Jun N-terminal kinase and the cyclin D1 promoter

    International Nuclear Information System (INIS)

    Zhang, Xiangning; Liu, Hui; Li, Binbin; Huang, Peichun; Shao, Jianyong; He, Zhiwei

    2012-01-01

    Tumor suppressor genes function to regulate and block tumor cell proliferation. To explore the mechanisms underlying the tumor suppression of BLU/ZMYND10 gene on a frequently lost human chromosomal region, an adenoviral vector with BLU cDNA insert was constructed. BLU was re-expressed in nasopharyngeal carcinoma cells by transfection or viral infection. Clonogenic growth was assayed; cell cycle was analyzed by flow cytometry-based DNA content detection; c-Jun N-terminal kinase (JNK) and cyclin D1 promoter activities were measured by reporter gene assay, and phosphorylation was measured by immunoblotting. The data for each pair of groups were compared with Student t tests. BLU inhibits clonogenic growth of nasopharyngeal carcinoma cells, arrests cell cycle at G1 phase, downregulates JNK and cyclin D1 promoter activities, and inhibits phosphorylation of c-Jun. BLU inhibits growth of nasopharyngeal carcinoma cells by regulation of the JNK-cyclin D1 axis to exert tumor suppression

  16. Chikungunya virus–induced autophagy delays caspase-dependent cell death

    Science.gov (United States)

    Joubert, Pierre-Emmanuel; Werneke, Scott W.; de la Calle, Claire; Guivel-Benhassine, Florence; Giodini, Alessandra; Peduto, Lucie; Levine, Beth; Schwartz, Olivier; Lenschow, Deborah J.

    2012-01-01

    Autophagy is an important survival pathway and can participate in the host response to infection. Studying Chikungunya virus (CHIKV), the causative agent of a major epidemic in India, Southeast Asia, and southern Europe, we reveal a novel mechanism by which autophagy limits cell death and mortality after infection. We use biochemical studies and single cell multispectral assays to demonstrate that direct infection triggers both apoptosis and autophagy. CHIKV-induced autophagy is mediated by the independent induction of endoplasmic reticulum and oxidative stress pathways. These cellular responses delay apoptotic cell death by inducing the IRE1α–XBP-1 pathway in conjunction with ROS-mediated mTOR inhibition. Silencing of autophagy genes resulted in enhanced intrinsic and extrinsic apoptosis, favoring viral propagation in cultured cells. Providing in vivo evidence for the relevance of our findings, Atg16LHM mice, which display reduced levels of autophagy, exhibited increased lethality and showed a higher sensitivity to CHIKV-induced apoptosis. Based on kinetic studies and the observation that features of apoptosis and autophagy were mutually exclusive, we conclude that autophagy inhibits caspase-dependent cell death but is ultimately overwhelmed by viral replication. Our study suggests that inducers of autophagy may limit the pathogenesis of acute Chikungunya disease. PMID:22508836

  17. Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells.

    Science.gov (United States)

    Morotomi-Yano, Keiko; Akiyama, Hidenori; Yano, Ken-ichi

    2013-08-30

    Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Methuosis: nonapoptotic cell death associated with vacuolization of macropinosome and endosome compartments.

    Science.gov (United States)

    Maltese, William A; Overmeyer, Jean H

    2014-06-01

    Apoptosis is the most widely recognized form of physiological programmed cell death. During the past three decades, various nonapoptotic forms of cell death have gained increasing attention, largely because of their potential importance in pathological processes, toxicology, and cancer therapy. A recent addition to the panoply of cell death phenotypes is methuosis. The neologism is derived from the Greek methuo (to drink to intoxication) because the hallmark of this form of cell death is displacement of the cytoplasm by large fluid-filled vacuoles derived from macropinosomes. The demise of the cell resembles many forms of necrosis, insofar as there is a loss of metabolic capacity and plasma membrane integrity, without the cell shrinkage and nuclear fragmentation associated with apoptosis. Methuosis was initially defined in glioblastoma cells after ectopic expression of activated Ras, but recent reports have described small molecules that can induce the features of methuosis in a broad spectrum of cancer cells, including those that are resistant to conventional apoptosis-inducing drugs. This review summarizes the available information about the distinguishing morphological characteristics and underlying mechanisms of methuosis. We compare and contrast methuosis with other cytopathological conditions in which accumulation of clear cytoplasmic vacuoles is a prominent feature. Finally, we highlight key questions that need to be answered to determine whether methuosis truly represents a unique form of regulated cell death. Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  19. Effects of emodin on the demethylation of tumor-suppressor genes in pancreatic cancer PANC-1 cells.

    Science.gov (United States)

    Zhang, Hao; Chen, Liang; Bu, He-Qi; Yu, Qing-Jiang; Jiang, Dan-Dan; Pan, Feng-Ping; Wang, Yu; Liu, Dian-Lei; Lin, Sheng-Zhang

    2015-06-01

    Emodin, a natural anthraquinone derivative isolated from Rheum palmatum, has been reported to inhibit the growth of pancreatic cancer cells through different modes of action; yet, the detailed mechanism remains unclear. In the present study, we hypothesized that emodin exerts its antitumor effect by participating in the regulation of the DNA methylation level. Our research showed that emodin inhibited the growth of pancreatic cancer PANC-1 cells in a dose- and time-dependent manner. Dot-blot results showed that 40 µM emodin significantly inhibited genomic 5 mC expression in the PANC-1 cells, and mRNA-Seq showed that different concentrations of emodin could alter the gene expression profile in the PANC-1 cells. BSP confirmed that the methylation levels of P16, RASSF1A and ppENK were decreased, while concomitantly the unmethylated status was increased. RT-PCR and western blotting results confirmed that the low expression or absence of expression of mRNA and protein in the PANC-1 cells was re-expressed following treatment with emodin. In conclusion, our study for the first time suggests that emodin inhibits pancreatic cancer cell growth, which may be related to the demethylation of tumor-suppressor genes. The related mechanism may be through the inhibition of methyltransferase expression.

  20. Silicon does not mitigate cell death in cultured tobacco BY-2 cells subjected to salinity without ethylene emission.

    Science.gov (United States)

    Liang, Xiaolei; Wang, Huahua; Hu, Yanfeng; Mao, Lina; Sun, Lili; Dong, Tian; Nan, Wenbin; Bi, Yurong

    2015-02-01

    Silicon induces cell death when ethylene is suppressed in cultured tobacco BY-2 cells. There is a crosstalk between Si and ethylene signaling. Silicon (Si) is beneficial for plant growth. It alleviates both biotic and abiotic stresses in plants. How Si works in plants is still mysterious. This study investigates the mechanism of Si-induced cell death in tobacco BY-2 cell cultures when ethylene is suppressed. Results showed that K2SiO3 alleviated the damage of NaCl stress. Si treatment rapidly increased ethylene emission and the expression of ethylene biosynthesis genes. Treatments with Si + Ag and Si + aminooxyacetic acid (AOA, ethylene biosynthesis inhibitor) reduced the cell growth and increased cell damage. The treatment with Si + Ag induced hydrogen peroxide (H2O2) generation and ultimately cell death. Some nucleus of BY-2 cells treated with Si + Ag appeared TUNEL positive. The inhibition of H2O2 and nitric oxide (NO) production reduced the cell death rate induced by Si + Ag treatment. Si eliminated the up-regulation of alternative pathway by Ag. These data suggest that ethylene plays an important role in Si function in plants. Without ethylene, Si not only failed to enhance plant resistance, but also elevated H2O2 generation and further induced cell death in tobacco BY-2 cells.

  1. Activation-induced cell death of dendritic cells is dependent on sphingosine kinase 1

    Directory of Open Access Journals (Sweden)

    Anja eSchwiebs

    2016-04-01

    Full Text Available Sphingosine 1-phosphate (S1P is an immune modulatory lipid mediator and has been implicated in numerous pathophysiological processes. S1P is produced by sphingosine kinase 1 (Sphk1 and Sphk2. Dendritic cells (DCs are central for the direction of immune responses and crucially involved in autoimmunity and cancerogenesis. In this study we examined the function and survival of bone marrow-derived DCs under long-term inflammatory stimulation. We observed that differentiated cells undergo activation-induced cell death upon LPS stimulation with an increased metabolic activity shortly after stimulation, followed by a rapid activation of caspase 3 and subsequent augmented apoptosis. Importantly, we highlight a profound role of Sphk1 in secretion of inflammatory cytokines and survival of dendritic cells that might be mediated by a change in sphingolipid levels as well as by a change in STAT3 expression. Cell growth during differentiation of Sphk1-deficient cells treated with the functional S1P receptor antagonist FTYP was reduced. Importantly, in dendritic cells we did not observe a compensatory regulation of Sphk2 mRNA in Sphk1-deficient cells. Instead, we discovered a massive increase in Sphk1 mRNA concentration upon long-term stimulation with LPS in wild type cells that might function as an attempt to rescue from inflammation-caused cell death. Taken together, in this investigation we describe details of a crucial involvement of sphingolipids and Sphk1 in activation-induced cell death during long-term immunogenic activity of DCs that might play an important role in autoimmunity and might explain the differences in immune response observed in in vivo studies of Sphk1 modulation.

  2. CD40 dependent exacerbation of immune mediated hepatitis by hepatic CD11b+ Gr-1+ myeloid derived suppressor cells in tumor bearing mice

    Science.gov (United States)

    Kapanadze, Tamar; Medina-Echeverz, José; Gamrekelashvili, Jaba; Weiss, Jonathan M.; Wiltrout, Robert H.; Kapoor, Veena; Hawk, Nga; Terabe, Masaki; Berzofsky, Jay A.; Manns, Michael P.; Wang, Ena; Marincola, Francesco M.; Korangy, Firouzeh; Greten, Tim F.

    2015-01-01

    Immunosuppressive CD11b+Gr-1+ myeloid-derived suppressor cells (MDSC) accumulate in the livers of tumor-bearing mice. We studied hepatic MDSC in two murine models of immune mediated hepatitis. Unexpectedly, treatment of tumor bearing mice with Concanavalin A or α-Galactosylceramide resulted in increased ALT and AST serum levels in comparison to tumor free mice. Adoptive transfer of hepatic MDSC into naïve mice exacerbated Concanavalin A induced liver damage. Hepatic CD11b+Gr-1+ cells revealed a polarized pro-inflammatory gene signature after Concanavalin A treatment. An interferon gamma- dependent up-regulation of CD40 on hepatic CD11b+Gr-1+ cells along with an up-regulation of CD80, CD86, and CD1d after Concanavalin A treatment was observed. Concanavalin A treatment resulted in a loss of suppressor function by tumor-induced CD11b+Gr-1+ MDSC as well as enhanced reactive oxygen species-mediated hepatotoxicity. CD40 knockdown in hepatic MDSC led to increased arginase activity upon Concanavalin A treatment and lower ALT/AST serum levels. Finally, blockade of arginase activity in Cd40−/− tumor-induced myeloid cells resulted in exacerbation of hepatitis and increased reactive oxygen species production in vivo. Our findings indicate that in a setting of acute hepatitis, tumor-induced hepatic MDSC act as pro-inflammatory immune effector cells capable of killing hepatocytes in a CD40-dependent manner. PMID:25616156

  3. Crotamine and crotoxin interact with tumor cells and trigger cell death

    International Nuclear Information System (INIS)

    Soares, Marcella Araugio; Pujatti, Priscilla Brunelli; Santos, Raquel Gouvea dos; Dias, Consuelo Latorre Fortes; Chavez Olortegui, Carlos Delfin; Santos, Wagner Gouvea dos

    2007-01-01

    Crotoxin (Crtx) and Crotamine (Crota) are polypeptides isolated from Crotalus durissus terrificus snake venom (CV). Previous reports have been shown therapeutic effects of Crotalus durissus terrificus venom and Crtx on skin, breast and lung tumours, although, the mechanisms of this antitumoral effect are still unknown. The aim of this work was to investigate the antitumoral effect of Crtx and Crota on brain tumours cells (GH3 and RT2) in vitro and their capacity of interaction with these tumour cells membranes. Cell survival after Crtx and Crota treatment was evaluated by MTT assay in different times post-treatment and apoptosis was evaluated by DAPI staining. In order to evaluate the specific interaction of Crtx and Crota, these polypeptides were radiolabelled, using 125 I as radiotracer and binding assays were performed. The results were compared with the binding in nontumoral brain tissue. Crtx and Crota induced apoptosis on both tumour cells lineages but, Crota was more powerful than Crtx 90% and 20% cell death for RT2 cells; 80% and 20% cell death for GH3 cells, respectively). Both 125 I-Crtx and 125 I-Crota bound specifically in glioblastoma membranes. Nonetheless, CV polypeptides recognised glioblastoma cells with higher specificity than normal brain tissue. These results suggest that the Crtx and Crota interactions with the plasmatic membrane of tumour cells may be the first step of the cascade of signalling that trigger their antitumoral effect. (author)

  4. Calcium regulates cell death in cancer: Roles of the mitochondria and mitochondria-associated membranes (MAMs).

    Science.gov (United States)

    Danese, Alberto; Patergnani, Simone; Bonora, Massimo; Wieckowski, Mariusz R; Previati, Maurizio; Giorgi, Carlotta; Pinton, Paolo

    2017-08-01

    Until 1972, the term 'apoptosis' was used to differentiate the programmed cell death that naturally occurs in organismal development from the acute tissue death referred to as necrosis. Many studies on cell death and programmed cell death have been published and most are, at least to some degree, related to cancer. Some key proteins and molecular pathways implicated in cell death have been analyzed, whereas others are still being actively researched; therefore, an increasing number of cellular compartments and organelles are being implicated in cell death and cancer. Here, we discuss the mitochondria and subdomains of the endoplasmic reticulum (ER) that interact with mitochondria, the mitochondria-associated membranes (MAMs), which have been identified as critical hubs in the regulation of cell death and tumor growth. MAMs-dependent calcium (Ca 2+ ) release from the ER allows selective Ca 2+ uptake by the mitochondria. The perturbation of Ca 2+ homeostasis in cancer cells is correlated with sustained cell proliferation and the inhibition of cell death through the modulation of Ca 2+ signaling. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. [Compound K suppresses myeloid-derived suppressor cells in a mouse model bearing CT26 colorectal cancer xenograft].

    Science.gov (United States)

    Wang, Rong; Li, Yalin; Wang, Wuzhou; Zhou, Meijuan; Cao, Zhaohui

    2015-05-01

    To investigate the effect of ginseng-derived compound K (C-K) on apoptosis, immunosuppressive activity, and pro-inflammatory cytokine production of myeloid-derived suppressor cells (MDSCs) from mice bearing colorectal cancer xenograft. Flow-sorted bone marrow MDSCs from Balb/c mice bearing CT26 tumor xenograft were treated with either C-K or PBS for 96 h and examined for apoptosis with Annexin V/7-AAD, Cox-2 and Arg-1 expressions using qRT-PCR, and supernatant IL-1β, IL-6, and IL-17 levels with ELISA. C-K- or PBS-treated MDSCs were subcutaneously implanted along with CT26 tumor cells in WT Balb/c mice, and the tumor size and morphology were evaluated 21 days later. C-K treatment significantly increased the percentages of early and late apoptotic MDSCs in vitro (Pimmunosuppresive effect of MDSCs to inhibit tumor cell proliferation in mice, which suggests a new strategy of tumor therapy by targeting MDSCs.

  6. Singapore grouper iridovirus, a large DNA virus, induces nonapoptotic cell death by a cell type dependent fashion and evokes ERK signaling.

    Science.gov (United States)

    Huang, Xiaohong; Huang, Youhua; Ouyang, Zhengliang; Xu, Lixiao; Yan, Yang; Cui, Huachun; Han, Xin; Qin, Qiwei

    2011-08-01

    Virus induced cell death, including apoptosis and nonapoptotic cell death, plays a critical role in the pathogenesis of viral diseases. Singapore grouper iridovirus (SGIV), a novel iridovirus of genus Ranavirus, causes high mortality and heavy economic losses in grouper aquaculture. Here, using fluorescence microscopy, electron microscopy and biochemical assays, we found that SGIV infection in host (grouper spleen, EAGS) cells evoked nonapoptotic programmed cell death (PCD), characterized by appearance of cytoplasmic vacuoles and distended endoplasmic reticulum, in the absence of DNA fragmentation, apoptotic bodies and caspase activation. In contrast, SGIV induced typical apoptosis in non-host (fathead minnow, FHM) cells, as evidenced by caspase activation and DNA fragmentation, suggesting that SGIV infection induced nonapoptotic cell death by a cell type dependent fashion. Furthermore, viral replication was essential for SGIV induced nonapoptotic cell death, but not for apoptosis. Notably, the disruption of mitochondrial transmembrane potential (ΔΨm) and externalization of phosphatidylserine (PS) were not detected in EAGS cells but in FHM cells after SGIV infection. Moreover, the extracellular signal-regulated kinase (ERK) signaling was involved in SGIV infection induced nonapoptotic cell death and viral replication. This is a first demonstration of ERK-mediated nonapoptotic cell death induced by a DNA virus. These findings contribute to understanding the mechanisms of iridovirus pathogenesis.

  7. Myeloid-derived suppressor cell functionality and interaction with Leishmania major parasites differ in C57BL/6 and BALB/c mice.

    Science.gov (United States)

    Schmid, Maximilian; Zimara, Nicole; Wege, Anja Kathrin; Ritter, Uwe

    2014-11-01

    Myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of CD11b+ cells. According to the surface molecules Ly6G and Ly6C (where Ly6G and Ly6C are lymphocyte antigen 6, locus G and C, respectively), MDSCs are further divided into monocytic (Mo-MDSCs, CD11b+ /Ly6C(high) /Ly6G-) and polymorphonucleated suppressor cells (PMN-MDSCs, CD11b+ /Ly6C(int) /Ly6G+). Most published manuscripts focus on the suppressive role of MDSCs in cancer, whereas their impact on adaptive immunity against obligatory intracellular parasites is not well understood. Furthermore, it is not clear how the genetic background of mice influences MDSC functionality. Therefore, we implemented an experimental model of leishmaniasis, and analyzed MDSC maturation and the impact of MDSCs on the parasite-specific T-cell responses in resistant C57BL/6 and susceptible BALB/c mice. This experimental setup demonstrated the impaired ability of BALB/c mice to produce Mo-MDSCs when compared with C57BL/6 mice. This phenotype is detectable after subcutaneous infection with parasites and is specifically represented by a reduced accumulation of Mo-MDSCs at the site of infection in BALB/c mice. Moreover, infected C57BL/6-derived MDSCs were able to suppress Leishmania-specific CD4+ -cell proliferation, whereas BALB/c-derived MDSCs harboring parasites lost this suppressive function. In conclusion, we demonstrate that (i) genetic background defines MDSC differentiation; and (ii) Leishmania major parasites are able to modulate the suppressive effect of MDSCs in a strain-dependent manner. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Simultaneous activation of mitophagy and autophagy by staurosporine protects against dopaminergic neuronal cell death.

    Science.gov (United States)

    Ha, Ji-Young; Kim, Ji-Soo; Kim, Seo-Eun; Son, Jin H

    2014-02-21

    Abnormal autophagy is frequently observed during dopaminergic neurodegeneration in Parkinson's disease (PD). However, it is not yet firmly established whether active autophagy is beneficial or pathogenic with respect to dopaminergic cell loss. Staurosporine, a common inducer of apoptosis, is often used in mechanistic studies of dopaminergic cell death. Here we report that staurosporine activates both autophagy and mitophagy simultaneously during dopaminergic neuronal cell death, and evaluate the physiological significance of these processes during cell death. First, staurosporine treatment resulted in induction of autophagy in more than 75% of apoptotic cells. Pharmacological inhibition of autophagy by bafilomycin A1 decreased significantly cell viability. In addition, staurosporine treatment resulted in activation of the PINK1-Parkin mitophagy pathway, of which deficit underlies some familial cases of PD, in the dopaminergic neuronal cell line, SN4741. The genetic blockade of this pathway by PINK1 null mutation also dramatically increased staurosporine-induced cell death. Taken together, our data suggest that staurosporine induces both mitophagy and autophagy, and that these pathways exert a significant neuroprotective effect, rather than a contribution to autophagic cell death. This model system may therefore be useful for elucidating the mechanisms underlying crosstalk between autophagy, mitophagy, and cell death in dopaminergic neurons. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  9. Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells

    Energy Technology Data Exchange (ETDEWEB)

    Morotomi-Yano, Keiko; Akiyama, Hidenori [Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan); Yano, Ken-ichi, E-mail: yanoken@kumamoto-u.ac.jp [Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-8555 (Japan)

    2013-08-30

    Highlights: •Nanosecond pulsed electric field (nsPEF) is a new and unique means for life sciences. •Apoptosis was induced by nsPEF exposure in Jurkat cells. •No signs of apoptosis were detected in HeLa S3 cells exposed to nsPEFs. •Formation of poly(ADP-ribose) was induced in nsPEF-exposed HeLa S3 cells. •Two distinct modes of cell death were activated by nsPEF in a cell-dependent manner. -- Abstract: Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs.

  10. Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells

    International Nuclear Information System (INIS)

    Morotomi-Yano, Keiko; Akiyama, Hidenori; Yano, Ken-ichi

    2013-01-01

    Highlights: •Nanosecond pulsed electric field (nsPEF) is a new and unique means for life sciences. •Apoptosis was induced by nsPEF exposure in Jurkat cells. •No signs of apoptosis were detected in HeLa S3 cells exposed to nsPEFs. •Formation of poly(ADP-ribose) was induced in nsPEF-exposed HeLa S3 cells. •Two distinct modes of cell death were activated by nsPEF in a cell-dependent manner. -- Abstract: Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs

  11. Mitochondrial permeability transition and cell death: the role of cyclophilin D

    Directory of Open Access Journals (Sweden)

    Sabzali eJavadov

    2013-04-01

    Full Text Available Mitochondria serve as a powerhouse which provides near 90% of ATP necessary for cell life. However, recent studies provide strong evidence that mitochondria also play a central role in cell death. Irreversible mitochondrial permeability transition (mPT at high conductance in response to oxidative or other cellular stresses is accompanied by formation of pathological and non-specific mPT pores (mPTP in the inner membrane of mitochondria. Mitochondrial PTP can serve as a target to prevent cell death under pathological conditions such as cardiac and brain ischemia/reperfusion injury and diabetes. On the other hand, mPTP can be used as an executioner to specifically induce cell death thus blocking tumorigenesis in cancer diseases. Despite many studies, the molecular identity of the mPTP remains unclear. At present, cyclophilin D (CyP-D represents the only mPTP protein which plays an essential role in pore formation. This review will discuss direct and indirect mechanisms underlying CyP-D interaction with a target protein of the mPTP complex. Understanding of the mechanisms of mPTP formation will be helpful to further develop new pharmacological agents targeting mitochondria-mediated cell death.

  12. Chloroplasts activity and PAP-signaling regulate programmed cell death in Arabidopsis

    KAUST Repository

    Bruggeman, Quentin

    2016-01-09

    Programmed cell death (PCD) is a crucial process both for plant development and responses to biotic and abiotic stress. There is accumulating evidence that chloroplasts may play a central role during plant PCD as for mitochondria in animal cells, but it is still unclear whether they participate in PCD onset, execution, or both. To tackle this question, we have analyzed the contribution of chloroplast function to the cell death phenotype of the myoinositol phosphate synthase1 (mips1) mutant that forms spontaneous lesions in a light-dependent manner. We show that photosynthetically active chloroplasts are required for PCD to occur in mips1, but this process is independent of the redox state of the chloroplast. Systematic genetic analyses with retrograde signaling mutants reveal that 3’-phosphoadenosine 5’-phosphate, a chloroplast retrograde signal that modulates nuclear gene expression in response to stress, can inhibit cell death and compromises plant innate immunity via inhibition of the RNA-processing 5’-3’ exoribonucleases. Our results provide evidence for the role of chloroplast-derived signal and RNA metabolism in the control of cell death and biotic stress response. © 2016 American Society of Plant Biologists. All Rights Reserved.

  13. Gelsolin functions as a metastasis suppressor in B16-BL6 mouse melanoma cells and requirement of the carboxyl-terminus for its effect.

    Science.gov (United States)

    Fujita, H; Okada, F; Hamada , J; Hosokawa, M; Moriuchi, T; Koya, R C; Kuzumaki, N

    2001-09-01

    Gelsolin, an actin-binding protein, is implicated as a critical regulator in cell motility. In addition, we have reported that cellular levels of gelsolin are decreased in various tumor cells, and overexpression of gelsolin by gene transfer suppresses tumorigenicity. We sought to assess the effects of gelsolin overexpression on metastasis and to determine the importance of a carboxyl-terminus that confers Ca(2+) dependency on gelsolin for effects of its overexpression. Expression vectors with cDNA encoding either full-length wild-type or His321 mutant form, isolated from a flat revertant of Ras-transformed cells and a carboxyl-terminal truncate, C-del of gelsolin, were transfected into a highly metastatic murine melanoma cell line, B16-BL6. Expression of introduced cDNA in transfectants was confirmed using Western blotting, 2-dimensional gel electrophoresis and reverse transcription-polymerase chain reaction (RT-PCR). We characterized phenotypes of transfectants, such as growth rate, colony formation in soft agar, cell motility and metastasis formation in vivo. Transfectants expressing the wild-type, His321 mutant and C-del gelsolin exhibited reduced growth ability in soft agar. Although expression of integrin beta1 or alpha4 on the cell surface of transfectants was not changed, wild-type and His321 mutant gelsolin, except for C-del gelsolin, exhibited retardation of cell spreading, reduced chemotatic migration to fibronectin and suppressed lung colonization in spontaneous metastasis assay. Gelsolin may function as a metastasis suppressor as well as a tumor suppressor gene. The carboxyl-terminus of gelsolin is important for retardation of cell spreading, reduced chemotasis and metastasis suppression. Copyright 2001 Wiley-Liss, Inc.

  14. Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death.

    Science.gov (United States)

    Narayanan, Kannan Badri; Ali, Manaf; Barclay, Barry J; Cheng, Qiang Shawn; D'Abronzo, Leandro; Dornetshuber-Fleiss, Rita; Ghosh, Paramita M; Gonzalez Guzman, Michael J; Lee, Tae-Jin; Leung, Po Sing; Li, Lin; Luanpitpong, Suidjit; Ratovitski, Edward; Rojanasakul, Yon; Romano, Maria Fiammetta; Romano, Simona; Sinha, Ranjeet K; Yedjou, Clement; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Brown, Dustin G; Ryan, Elizabeth P; Colacci, Annamaria; Hamid, Roslida A; Mondello, Chiara; Raju, Jayadev; Salem, Hosni K; Woodrick, Jordan; Scovassi, A Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Kim, Seo Yun; Bisson, William H; Lowe, Leroy; Park, Hyun Ho

    2015-06-01

    Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. 8-aminoadenosine enhances radiation-induced cell death in human lung carcinoma A549 cells

    International Nuclear Information System (INIS)

    Meike, Shunsuke; Yamamori, Tohru; Yasui, Hironobu; Eitaki, Masato; Inanami, Osamu; Matsuda, Akira

    2011-01-01

    The combination of a chemotherapeutic agent and radiation is widely applied to enhance cell death in solid tumor cells in cancer treatment. The purine analogue 8-aminoadenosine (8-NH 2 -Ado) is known to be a transcription inhibitor that has proved very effective in multiple myeloma cell lines and primary indolent leukemia cells. In this report, to examine whether 8-NH 2 -Ado had the ability to enhance the radiation-induced cell killing in solid tumor cells, human lung adenocarcinoma A549 cells were irradiated in the presence and absence of 8-NH 2 -Ado. 8-NH 2 -Ado significantly increased reproductive cell death and apoptosis in A549 cells exposed to X-rays. When peptide inhibitors against caspase-3, -8, and -9 were utilized to evaluate the involvement of caspases, all inhibitors suppressed the enhancement of radiation-induced apoptosis, suggesting that not only mitochondria-mediated apoptotic signal transduction pathways but also death receptor-mediated pathways were involved in this enhancement of apoptosis. In addition, in the cells exposed to the treatment combining X-irradiation and 8-NH 2 -Ado, reduction of the intracellular ATP concentration was essential for survival, and down-regulation of the expression of antiapoptotic proteins such as survivin and X-linked inhibitor of apoptosis protein (XIAP) was observed. These results indicate that 8-NH 2 -Ado has potential not only as an anti-tumor drug for leukemia and lymphoma but also as a radiosensitizing agent for solid tumors. (author)

  16. DRAM Triggers Lysosomal Membrane Permeabilization and Cell Death in CD4+ T Cells Infected with HIV

    Science.gov (United States)

    Laforge, Mireille; Limou, Sophie; Harper, Francis; Casartelli, Nicoletta; Rodrigues, Vasco; Silvestre, Ricardo; Haloui, Houda; Zagury, Jean-Francois; Senik, Anna; Estaquier, Jerome

    2013-01-01

    Productive HIV infection of CD4+ T cells leads to a caspase-independent cell death pathway associated with lysosomal membrane permeabilization (LMP) and cathepsin release, resulting in mitochondrial outer membrane permeabilization (MOMP). Herein, we demonstrate that HIV infection induces damage-regulated autophagy modulator (DRAM) expression in a p53-dependent manner. Knocking down the expression of DRAM and p53 genes with specific siRNAs inhibited autophagy and LMP. However, inhibition of Atg5 and Beclin genes that prevents autophagy had a minor effect on LMP and cell death. The knock down of DRAM gene inhibited cytochrome C release, MOMP and cell death. However, knocking down DRAM, we increased viral infection and production. Our study shows for the first time the involvement of DRAM in host-pathogen interactions, which may represent a mechanism of defense via the elimination of infected cells. PMID:23658518

  17. Real-time monitoring of cisplatin-induced cell death.

    Directory of Open Access Journals (Sweden)

    Hamed Alborzinia

    Full Text Available Since the discovery of cisplatin more than 40 years ago and its clinical introduction in the 1970s an enormous amount of research has gone into elucidating the mechanism of action of cisplatin on tumor cells. With a novel cell biosensor chip system allowing continuous monitoring of respiration, glycolysis, and impedance we followed cisplatin treatment of different cancer cell lines in real-time. Our measurements reveal a first effect on respiration, in all cisplatin treated cell lines, followed with a significant delay by interference with glycolysis in HT-29, HCT-116, HepG2, and MCF-7 cells but not in the cisplatin-resistant cell line MDA-MB-231. Most strikingly, cell death started in all cisplatin-sensitive cell lines within 8 to 11 h of treatment, indicating a clear time frame from exposure, first response to cisplatin lesions, to cell fate decision. The time points of most significant changes were selected for more detailed analysis of cisplatin response in the breast cancer cell line MCF-7. Phosphorylation of selected signal transduction mediators connected with cellular proliferation, as well as changes in gene expression, were analyzed in samples obtained directly from sensor chips at the time points when changes in glycolysis and impedance occurred. Our online cell biosensor measurements reveal for the first time the time scale of metabolic response until onset of cell death under cisplatin treatment, which is in good agreement with models of p53-mediated cell fate decision.

  18. Curcumin Attenuates Staurosporine-Mediated Death of Retinal Ganglion Cells

    OpenAIRE

    Burugula, Balabharathi; Ganesh, Bhagyalaxmi S.; Chintala, Shravan K.

    2011-01-01

    The functional effect of curcumin, a free radical scavenger and an herbal medicine from Indian yellow curry spice, Curcuma longa, on protease-mediated retinal ganglion cell death was investigated. These results show, for the first time, that curcumin indeed prevents the protease-mediated death of RGCs, both in vitro and in vivo.

  19. Suppressor of cytokine signaling 1 modulates invasion and metastatic potential of colorectal cancer cells.

    Science.gov (United States)

    David, Muriel; Naudin, Cécile; Letourneur, Martine; Polrot, Mélanie; Renoir, Jack-Michel; Lazar, Vladimir; Dessen, Philippe; Roche, Serge; Bertoglio, Jacques; Pierre, Josiane

    2014-07-01

    Suppressor of cytokine signaling (SOCS) 1 is an inducible negative regulator of cytokine signaling but its role in human cancer is not completely established. Here we report that, while SOCS1 is expressed in normal colonic epithelium and colon adenocarcinomas, its level decreases during progression of colon adenocarcinomas, the lowest level being found in the most aggressive stage and least differentiated carcinomas. Forced expression of SOCS1 in metastatic colorectal SW620 cells reverses many characteristics of Epithelial-Mesenchymal Transition (EMT), as highlighted by the disappearance of the transcription factor ZEB1 and the mesenchymal form of p120ctn and the re-expression of E-cadherin. Furthermore, miRNA profiling indicated that SOCS1 also up-regulates the expression of the mir-200 family of miRNAs, which can promote the mesenchymal-epithelial transition and reduce tumor cell migration. Accordingly, overexpression of SOCS1 induced cell morphology changes and dramatically reduced tumor cell invasion in vitro. When injected in nude mice, SOCS1-expressing SW620 cells induced metastases in a smaller number of animals than parental SW620 cells, and did not generate any adrenal gland or bone metastasis. Overall, our results suggest that SOCS1 controls metastatic progression of colorectal tumors by preventing the mesenchymal-epithelial transition (MET), including E-cadherin expression. This pathway may be associated with survival to colorectal cancer by reducing the capacity of generating metastases. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  20. Programmes of cell death and autolysis in tracheary elements: when a suicidal cell arranges its own corpse removal.

    Science.gov (United States)

    Escamez, Sacha; Tuominen, Hannele

    2014-03-01

    Tracheary element (TE) differentiation represents a unique system to study plant developmental programmed cell death (PCD). TE PCD occurs after deposition of the secondary cell walls when an unknown signal induces tonoplast rupture and the arrest of cytoplasmic streaming. TE PCD is tightly followed by autolysis of the protoplast and partial hydrolysis of the primary cell walls. This review integrates TE differentiation, programmed cell death (PCD), and autolysis in a biological and evolutionary context. The collective evidence from the evolutionary and molecular studies suggests that TE differentiation consists primarily of a programme for cell death and autolysis under the direct control of the transcriptional master switches VASCULAR NAC DOMAIN 6 (VND6) and VND7. In this scenario, secondary cell walls represent a later innovation to improve the water transport capacity of TEs which necessitates transcriptional regulators downstream of VND6 and VND7. One of the most fascinating features of TEs is that they need to prepare their own corpse removal by expression and accumulation of hydrolases that are released from the vacuole after TE cell death. Therefore, TE differentiation involves, in addition to PCD, a programmed autolysis which is initiated before cell death and executed post-mortem. It has recently become clear that TE PCD and autolysis are separate processes with separate molecular regulation. Therefore, the importance of distinguishing between the cell death programme per se and autolysis in all plant PCD research and of careful description of the morphological, biochemical, and molecular sequences in each of these processes, is advocated.

  1. Two modes of cell death caused by exposure to nanosecond pulsed electric field.

    Directory of Open Access Journals (Sweden)

    Olga N Pakhomova

    Full Text Available High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF, are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation", leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF. These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.

  2. The PCNA-associated factor KIAA0101/p15PAF binds the potential tumor suppressor product p33ING1b

    International Nuclear Information System (INIS)

    Simpson, Fiona; Lammerts van Bueren, Kelly; Butterfield, Natalie; Bennetts, Jennifer S.; Bowles, Josephine; Adolphe, Christelle; Simms, Lisa A.; Young, Joanne; Walsh, Michael D.; Leggett, Barbara; Fowles, Lindsay F.; Wicking, Carol

    2006-01-01

    The KIAA0101/p15 PAF /OEATC-1 protein was initially isolated in a yeast two-hybrid screen for proliferating cell nuclear antigen (PCNA) binding partners, and was shown to bind PCNA competitively with the cell cycle regulator p21 WAF . PCNA is involved in DNA replication and damage repair. Using polyclonal antisera raised against a p15 PAF fusion protein, we have shown that in a range of mammalian tumor and non-tumor cell lines the endogenous p15 PAF protein localises to the nucleus and the mitochondria. Under normal conditions no co-localisation with PCNA could be detected, however following exposure to UV it was possible to co-immunoprecipitate p15 PAF and PCNA from a number of cell lines, suggesting a UV-enhanced association of the two proteins. Overexpression of p15 PAF in mammalian cells was also found to protect cells from UV-induced cell death. Based on similarities between the behaviour of p15 PAF and the potential tumor suppressor product p33ING1b, we have further shown that these two proteins interact in the same complex in cell cultures. This suggests that p15 PAF forms part of a larger protein complex potentially involved in the regulation of DNA repair, apoptosis and cell cycle progression

  3. Hepatic leukemia factor promotes resistance to cell death: Implications for therapeutics and chronotherapy

    International Nuclear Information System (INIS)

    Waters, Katrina M.; Sontag, Ryan L.; Weber, Thomas J.

    2013-01-01

    Physiological variation related to circadian rhythms and aberrant gene expression patterns are believed to modulate therapeutic efficacy, but the precise molecular determinants remain unclear. Here we examine the regulation of cell death by hepatic leukemia factor (HLF), which is an output regulator of circadian rhythms and is aberrantly expressed in human cancers, using an ectopic expression strategy in JB6 mouse epidermal cells and human keratinocytes. Ectopic HLF expression inhibited cell death in both JB6 cells and human keratinocytes, as induced by serum-starvation, tumor necrosis factor alpha and ionizing radiation. Microarray analysis indicates that HLF regulates a complex multi-gene transcriptional program encompassing upregulation of anti-apoptotic genes, downregulation of pro-apoptotic genes, and many additional changes that are consistent with an anti-death program. Collectively, our results demonstrate that ectopic expression of HLF, an established transcription factor that cycles with circadian rhythms, can recapitulate many features associated with circadian-dependent physiological variation. - Highlights: ► Circadian-dependent physiological variation impacts therapeutic efficacy. ► Hepatic leukemia factor inhibits cell death and is a candidate circadian factor. ► Hepatic leukemia factor anti-death program is conserved in murine and human cells. ► Transcriptomics indicates the anti-death program results from a systems response

  4. Hepatic leukemia factor promotes resistance to cell death: Implications for therapeutics and chronotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Waters, Katrina M. [Computational Biology and Bioinformatics, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Sontag, Ryan L. [Systems Toxicology Groups, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Weber, Thomas J., E-mail: Thomas.Weber@pnl.gov [Systems Toxicology Groups, Pacific Northwest National Laboratory, Richland, WA 99354 (United States)

    2013-04-15

    Physiological variation related to circadian rhythms and aberrant gene expression patterns are believed to modulate therapeutic efficacy, but the precise molecular determinants remain unclear. Here we examine the regulation of cell death by hepatic leukemia factor (HLF), which is an output regulator of circadian rhythms and is aberrantly expressed in human cancers, using an ectopic expression strategy in JB6 mouse epidermal cells and human keratinocytes. Ectopic HLF expression inhibited cell death in both JB6 cells and human keratinocytes, as induced by serum-starvation, tumor necrosis factor alpha and ionizing radiation. Microarray analysis indicates that HLF regulates a complex multi-gene transcriptional program encompassing upregulation of anti-apoptotic genes, downregulation of pro-apoptotic genes, and many additional changes that are consistent with an anti-death program. Collectively, our results demonstrate that ectopic expression of HLF, an established transcription factor that cycles with circadian rhythms, can recapitulate many features associated with circadian-dependent physiological variation. - Highlights: ► Circadian-dependent physiological variation impacts therapeutic efficacy. ► Hepatic leukemia factor inhibits cell death and is a candidate circadian factor. ► Hepatic leukemia factor anti-death program is conserved in murine and human cells. ► Transcriptomics indicates the anti-death program results from a systems response.

  5. Corosolic Acid Induces Non-Apoptotic Cell Death through Generation of Lipid Reactive Oxygen Species Production in Human Renal Carcinoma Caki Cells

    Directory of Open Access Journals (Sweden)

    Seon Min Woo

    2018-04-01

    Full Text Available Corosolic acid is one of the pentacyclic triterpenoids isolated from Lagerstroemia speciose and has been reported to exhibit anti-cancer and anti-proliferative activities in various cancer cells. In the present study, we investigated the molecular mechanisms of corosolic acid in cancer cell death. Corosolic acid induces a decrease of cell viability and an increase of cell cytotoxicity in human renal carcinoma Caki cells. Corosolic acid-induced cell death is not inhibited by apoptosis inhibitor (z-VAD-fmk, a pan-caspase inhibitor, necroptosis inhibitor (necrostatin-1, or ferroptosis inhibitors (ferrostatin-1 and deferoxamine (DFO. Furthermore, corosolic acid significantly induces reactive oxygen species (ROS levels, but antioxidants (N-acetyl-l-cysteine (NAC and trolox do not inhibit corosolic acid-induced cell death. Interestingly, corosolic acid induces lipid oxidation, and α-tocopherol markedly prevents corosolic acid-induced lipid peroxidation and cell death. Anti-chemotherapeutic effects of α-tocopherol are dependent on inhibition of lipid oxidation rather than inhibition of ROS production. In addition, corosolic acid induces non-apoptotic cell death in other renal cancer (ACHN and A498, breast cancer (MDA-MB231, and hepatocellular carcinoma (SK-Hep1 and Huh7 cells, and α-tocopherol markedly inhibits corosolic acid-induced cell death. Therefore, our results suggest that corosolic acid induces non-apoptotic cell death in cancer cells through the increase of lipid peroxidation.

  6. The von Hippel-Lindau tumor suppressor gene inhibits hepatocyte growth factor/scatter factor-induced invasion and branching morphogenesis in renal carcinoma cells.

    Science.gov (United States)

    Koochekpour, S; Jeffers, M; Wang, P H; Gong, C; Taylor, G A; Roessler, L M; Stearman, R; Vasselli, J R; Stetler-Stevenson, W G; Kaelin, W G; Linehan, W M; Klausner, R D; Gnarra, J R; Vande Woude, G F

    1999-09-01

    Loss of function in the von Hippel-Lindau (VHL) tumor suppressor gene occurs in familial and most sporadic renal cell carcinomas (RCCs). VHL has been linked to the regulation of cell cycle cessation (G(0)) and to control of expression of various mRNAs such as for vascular endothelial growth factor. RCC cells express the Met receptor tyrosine kinase, and Met mediates invasion and branching morphogenesis in many cell types in response to hepatocyte growth factor/scatter factor (HGF/SF). We examined the HGF/SF responsiveness of RCC cells containing endogenous mutated (mut) forms of the VHL protein (VHL-negative RCC) with that of isogenic cells expressing exogenous wild-type (wt) VHL (VHL-positive RCC). We found that VHL-negative 786-0 and UOK-101 RCC cells were highly invasive through growth factor-reduced (GFR) Matrigel-coated filters and exhibited an extensive branching morphogenesis phenotype in response to HGF/SF in the three-dimensional (3D) GFR Matrigel cultures. In contrast, the phenotypes of A498 VHL-negative RCC cells were weaker, and isogenic RCC cells ectopically expressing wt VHL did not respond at all. We found that all VHL-negative RCC cells expressed reduced levels of tissue inhibitor of metalloproteinase 2 (TIMP-2) relative to the wt VHL-positive cells, implicating VHL in the regulation of this molecule. However, consistent with the more invasive phenotype of the 786-0 and UOK-101 VHL-negative RCC cells, the levels of TIMP-1 and TIMP-2 were reduced and levels of the matrix metalloproteinases 2 and 9 were elevated compared to the noninvasive VHL-positive RCC cells. Moreover, recombinant TIMPs completely blocked HGF/SF-mediated branching morphogenesis, while neutralizing antibodies to the TIMPs stimulated HGF/SF-mediated invasion in vitro. Thus, the loss of the VHL tumor suppressor gene is central to changes that control tissue invasiveness, and a more invasive phenotype requires additional genetic changes seen in some but not all RCC lines. These

  7. Delayed cell death associated with mitotic catastrophe in γ-irradiated stem-like glioma cells

    International Nuclear Information System (INIS)

    Firat, Elke; Gaedicke, Simone; Tsurumi, Chizuko; Esser, Norbert; Weyerbrock, Astrid; Niedermann, Gabriele

    2011-01-01

    Stem-like tumor cells are regarded as highly resistant to ionizing radiation (IR). Previous studies have focused on apoptosis early after irradiation, and the apoptosis resistance observed has been attributed to reduced DNA damage or enhanced DNA repair compared to non-stem tumor cells. Here, early and late radioresponse of patient-derived stem-like glioma cells (SLGCs) and differentiated cells directly derived from them were examined for cell death mode and the influence of stem cell-specific growth factors. Primary SLGCs were propagated in serum-free medium with the stem-cell mitogens epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2). Differentiation was induced by serum-containing medium without EGF and FGF. Radiation sensitivity was evaluated by assessing proliferation, clonogenic survival, apoptosis, and mitotic catastrophe. DNA damage-associated γH2AX as well as p53 and p21 expression were determined by Western blots. SLGCs failed to apoptose in the first 4 days after irradiation even at high single doses up to 10 Gy, but we observed substantial cell death later than 4 days postirradiation in 3 of 6 SLGC lines treated with 5 or 10 Gy. This delayed cell death was observed in 3 of the 4 SLGC lines with nonfunctional p53, was associated with mitotic catastrophe and occurred via apoptosis. The early apoptosis resistance of the SLGCs was associated with lower γH2AX compared to differentiated cells, but we found that the stem-cell culture cytokines EGF plus FGF-2 strongly reduce γH2AX levels. Nonetheless, in two p53-deficient SLGC lines examined γIR-induced apoptosis even correlated with EGF/FGF-induced proliferation and mitotic catastrophe. In a line containing CD133-positive and -negative stem-like cells, the CD133-positive cells proliferated faster and underwent more γIR-induced mitotic catastrophe. Our results suggest the importance of delayed apoptosis, associated mitotic catastrophe, and cellular proliferation for γIR-induced death of

  8. Alterations of tumor suppressor genes (Rb, p16, p27 and p53) and an increased FDG uptake in lung cancer

    International Nuclear Information System (INIS)

    Sasaki, Masayuki; Sugio, Kenji; Kuwabara, Yasuo

    2003-01-01

    The FDG uptake in lung cancer is considered to reflect the degree of malignancy, while alterations of some tumor suppressor genes are considered to be related to the malignant biological behavior of tumors. The aim of this study is to examine the relationship between FDG-PET and alterations in the tumor suppression genes of lung cancer. We examined 28 patients with primary lung cancer who underwent FDG-PET before surgery consisting of 17 patients with adenocarcinoma, 10 with squamous cell carcinoma and 1 with large cell carcinoma. The FDG-PET findings were evaluated based on the standardized uptake value (SUV). Alterations in the tumor suppressor genes, Rb, p16, p27 and p53, were evaluated immunohistochemically. The FDG uptake in lung cancer with alteration in each tumor suppressor gene tended to be higher than in those genes without alterations, although the differences were not significant. In 15 tumors with alterations in either tumor suppressor genes, the FDG uptake was 6.83±3.21. On the other hand, the mean FDG uptake was 1.95 in 2 tumors without alterations in any genes. The difference in the FDG uptake between the 2 groups was statistically significant (p<0.001). In conclusion, the presence of abnormalities in the tumor suppressor genes, which results in an accelerated cell proliferation, is thus considered to increase the FDG uptake in lung cancer. (author)

  9. Vacuolar processing enzyme in plant programmed cell death

    Directory of Open Access Journals (Sweden)

    Noriyuki eHatsugai

    2015-04-01

    Full Text Available Vacuolar processing enzyme (VPE is a cysteine proteinase originally identified as the proteinase responsible for the maturation and activation of vacuolar proteins in plants, and it is known to be an orthologue of animal asparaginyl endopeptidase (AEP/VPE/legumain. VPE has been shown to exhibit enzymatic properties similar to that of caspase 1, which is a cysteine protease that mediates the programmed cell death (PCD pathway in animals. Although there is limited sequence identity between VPE and caspase 1, their predicted three-dimensional structures revealed that the essential amino-acid residues for these enzymes form similar pockets for the substrate peptide YVAD. In contrast to the cytosolic localization of caspases, VPE is localized in vacuoles. VPE provokes vacuolar rupture, initiating the proteolytic cascade leading to PCD in the plant immune response. It has become apparent that the VPE-dependent PCD pathway is involved not only in the immune response, but also in the responses to a variety of stress inducers and in the development of various tissues. This review summarizes the current knowledge on the contribution of VPE to plant PCD and its role in vacuole-mediated cell death, and it also compares VPE with the animal cell death executor caspase 1.

  10. Potential role of TRIM3 as a novel tumour suppressor in colorectal cancer (CRC) development.

    Science.gov (United States)

    Piao, Mei-Yu; Cao, Hai-Long; He, Na-Na; Xu, Meng-Que; Dong, Wen-Xiao; Wang, Wei-Qiang; Wang, Bang-Mao; Zhou, Bing

    2016-01-01

    Colorectal cancer (CRC) is the third leading cause of cancer-related mortality in the United States. Recent cancer genome-sequencing efforts and complementary functional studies have led to the identification of a collection of candidate 'driver' genes involved in CRC tumorigenesis. Tripartite motif (TRIM3) is recently identified as a tumour suppressor in glioblastoma but this tumour-suppressive function has not been investigated in CRC. In this study, we investigated the potential role of TRIM3 as a tumour suppressor in CRC development by manipulating the expression of TRIM3 in two authentic CRC cell lines, HCT116 and DLD1, followed by various functional assays, including cell proliferation, colony formation, scratch wound healing, soft agar, and invasion assays. Xenograft experiment was performed to examine in vivo tumour-suppressive properties of TRIM3. Small-interfering RNA (siRNA) mediated knockdown of TRIM3 conferred growth advantage in CRC cells. In contrast, overexpression of TRIM3 affected cell survival, cell migration, anchorage independent growth and invasive potential in CRC cells. In addition, TRIM3 was found to be down-regulated in human colon cancer tissues compared with matched normal colon tissues. Overexpression of TRIM3 significantly inhibited tumour growth in vivo using xenograft mouse models. Mechanistic investigation revealed that TRIM3 can regulate p53 protein level through its stabilisation. TRIM3 functions as a tumour suppressor in CRC progression. This tumour-suppressive function is exerted partially through regulation of p53 protein. Therefore, this protein may represent a novel therapeutic target for prevention or intervention of CRC.

  11. Induction of cancer cell death by proton beam in tumor hypoxic region

    International Nuclear Information System (INIS)

    Lee, Y. M.; Heo, T. R.; Lee, K. B.; Jang, K. H.; Kim, H. N.; Lee, S. H.; Jeong, M. H.

    2008-04-01

    Proton beam has been applied to treat various tumor patients in clinical studies. However, it is still undefined whether proton radiation can inhibit the blood vessel formation and induce the cell death in vascular endothelial cells in growing organs. The aim of this study are first, to develop an optimal animal model for the observation of blood vessel development with low dose of proton beam and second, to investigate the effect of low dose proton beam on the inhibition of blood vessel formation induced by hypoxic conditions. In this study, flk1-GFP transgenic zebrafish embryos were used to directly visualize and determine the inhibition of blood vessels by low dose (1, 2, 5 Gy) of proton beam with spread out Bragg peak (SOBP). And we observed cell death by acridine orange staining at 96 hours post fertilization (hpf) stage of embryos after proton irradiation. We also compared the effects of proton beam with those of gamma-ray. An antioxidant, N-acetyl cystein (NAC) was used to investigate whether reactive oxygen species (ROS) were involved in the cell deaths induced by proton irradiation. Irradiated flk-1-GFP transgenic embryos with proton beam irradiation (35 MeV, spread out Bragg peak, SOBP) demonstrated a marked inhibition of embryonic growth and an altered fluorescent blood vessel development in the trunk region. When the cells with DNA damage in the irradiated zebrafish were stained with acridine orange, green fluorescent cell death spots were increased in trunk regions compared to non-irradiated control embryos. Proton beam also significantly increased the cell death rate in human umbilical vein endothelial cells (HUVEC), but pretreatment of N-acetyl cystein (NAC), an antioxidant, recovered the proton-induced cell death rate (p<0.01). Moreover, pretreatment of NAC abrogated the effect of proton beam on the inhibition of trunk vessel development and malformation of trunk truncation. From this study, we found that proton radiation therapy can inhibit the

  12. Classification of suppressor additives based on synergistic and antagonistic ensemble effects

    Energy Technology Data Exchange (ETDEWEB)

    Broekmann, P., E-mail: peter.broekmann@iac.unibe.ch [BASF SE, Global Business Unit Electronic Materials, 67056 Ludwigshafen (Germany); Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Fluegel, A.; Emnet, C.; Arnold, M.; Roeger-Goepfert, C.; Wagner, A. [BASF SE, Global Business Unit Electronic Materials, 67056 Ludwigshafen (Germany); Hai, N.T.M. [Department of Chemistry and Biochemistry, University of Bern, Bern (Switzerland); Mayer, D. [BASF SE, Global Business Unit Electronic Materials, 67056 Ludwigshafen (Germany)

    2011-05-01

    Highlights: > Three fundamental types of suppressor additives for copper electroplating could be identified by means of potential transient measurements. > These suppressor additives differ in their synergistic and antagonistic interplay with anions that are chemisorbed on the metallic copper surface during electrodeposition. > In addition these suppressor chemistries reveal different barrier properties with respect to cupric ions and plating additives (Cl, SPS). - Abstract: Three fundamental types of suppressor additives for copper electroplating could be identified by means of potential transient measurements. These suppressor additives differ in their synergistic and antagonistic interplay with anions that are chemisorbed on the metallic copper surface during electrodeposition. In addition these suppressor chemistries reveal different barrier properties with respect to cupric ions and plating additives (Cl, SPS). While the type-I suppressor selectively forms efficient barriers for copper inter-diffusion on chloride-terminated electrode surfaces we identified a type-II suppressor that interacts non-selectively with any kind of anions chemisorbed on copper (chloride, sulfate, sulfonate). Type-I suppressors are vital for the superconformal copper growth mode in Damascene processing and show an antagonistic interaction with SPS (Bis-Sodium-Sulfopropyl-Disulfide) which involves the deactivation of this suppressor chemistry. This suppressor deactivation is rationalized in terms of compositional changes in the layer of the chemisorbed anions due to the competition of chloride and MPS (Mercaptopropane Sulfonic Acid) for adsorption sites on the metallic copper surface. MPS is the product of the dissociative SPS adsorption within the preexisting chloride matrix on the copper surface. The non-selectivity in the adsorption behavior of the type-II suppressor is rationalized in terms of anion/cation pairing effects of the poly-cationic suppressor and the anion-modified copper

  13. An unusual characteristic “flower-like” pattern: flash suppressor burns

    OpenAIRE

    Gurcan, Altun

    2012-01-01

    The case on contact shots from firearms with a flash suppressor is rare. When a rifle fitted with a flash suppressor is fired, the emerging soot-laden gas in the barrel escapes from the slits of the flash suppressor. If the shot is contact or near contact, the flash suppressor will produce a characteristic “flower-like” pattern of seared, blackened zones around the entrance. This paper presents the injury pattern of the flash suppressor in a 29-year-old man who committed suicide with a G3 aut...

  14. An unusual characteristic “flower-like” pattern: flash suppressor burns

    Science.gov (United States)

    Gurcan, Altun

    2012-01-01

    The case on contact shots from firearms with a flash suppressor is rare. When a rifle fitted with a flash suppressor is fired, the emerging soot-laden gas in the barrel escapes from the slits of the flash suppressor. If the shot is contact or near contact, the flash suppressor will produce a characteristic “flower-like” pattern of seared, blackened zones around the entrance. This paper presents the injury pattern of the flash suppressor in a 29-year-old man who committed suicide with a G3 automatic infantry rifle. PMID:23935280

  15. Pam2 lipopeptides systemically increase myeloid-derived suppressor cells through TLR2 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Akira; Shime, Hiroaki, E-mail: shime@med.hokudai.ac.jp; Takeda, Yohei; Azuma, Masahiro; Matsumoto, Misako; Seya, Tsukasa, E-mail: seya-tu@pop.med.hokudai.ac.jp

    2015-02-13

    Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells that exhibit potent immunosuppressive activity. They are increased in tumor-bearing hosts and contribute to tumor development. Toll-like receptors (TLRs) on MDSCs may modulate the tumor-supporting properties of MDSCs through pattern-recognition. Pam2 lipopeptides represented by Pam2CSK4 serve as a TLR2 agonist to exert anti-tumor function by dendritic cell (DC)-priming that leads to NK cell activation and cytotoxic T cell proliferation. On the other hand, TLR2 enhances tumor cell progression/invasion by activating tumor-infiltrating macrophages. How MDSCs respond to TLR2 agonists has not yet been determined. In this study, we found intravenous administration of Pam2CSK4 systemically up-regulated the frequency of MDSCs in EG7 tumor-bearing mice. The frequency of tumor-infiltrating MDSCs was accordingly increased in response to Pam2CSK4. MDSCs were not increased by Pam2CSK4 stimuli in TLR2 knockout (KO) mice. Adoptive transfer experiments using CFSE-labeled MDSCs revealed that the TLR2-positive MDSCs survived long in tumor-bearing mice in response to Pam2CSK4 treatment. Since the increased MDSC population sustained immune-suppressive properties, our study suggests that Pam2CSK4-triggered TLR2 activation enhances the MDSC potential and suppress antitumor immune response in tumor microenvironment. - Highlights: • Pam2CSK4 administration induces systemic accumulation of CD11b{sup +}Gr1{sup +} MDSCs. • TLR2 is essential for Pam2CSK4-induced accumulation of CD11b{sup +}Gr1{sup +} MDSCs. • Pam2CSK4 supports survival of CD11b{sup +}Gr1{sup +} MDSCs in vivo.

  16. XIAP Restricts TNF- and RIP3-Dependent Cell Death and Inflammasome Activation

    DEFF Research Database (Denmark)

    Yabal, Monica; Müller, Nicole; Adler, Heiko

    2014-01-01

    of XIAP or deletion of its RING domain lead to excessive cell death and IL-1β secretion from dendritic cells triggered by diverse Toll-like receptor stimuli. Aberrant IL-1β secretion is TNF dependent and requires RIP3 but is independent of cIAP1/cIAP2. The observed cell death also requires TNF and RIP3...... but proceeds independently of caspase-1/caspase-11 or caspase-8 function. Loss of XIAP results in aberrantly elevated ubiquitylation of RIP1 outside of TNFR complex I. Virally infected Xiap(-/-) mice present with symptoms reminiscent of XLP-2. Our data show that XIAP controls RIP3-dependent cell death and IL-1...

  17. Effects of aromatic amino acids on glutamate-induced neuronal cell death

    International Nuclear Information System (INIS)

    Zafar, Z.; Sumners, C.

    2005-01-01

    Glutamate accumulation is believed to lead to overstimulation of glutamate receptors which results in neuronal death. The protective effects of aromatic amino acids on glutamate induced neuronal cell death were examined using rat cerebral cortical neurons. Neuronal death is quantified by measuring lactate dehydrogenase (LDH) using a spectrophotometric microtiter plate reader (ELISA reader). Neuronal cells were incubated with varying doses of glutamate plus or minus the aromatic amino acid D-Phenylalanine (D-Phe) for different time periods to observe protection against cytotoxicity. Percent cytotoxicity was seen to follow a dose dependent rise with increasing concentrations of glutamate, reaching a plateau at around 100 -500 uM glutamate. Lower levels of cytotoxicity were achieved with cell exposed to D-Phe and Dibromo tyrosine (DBrT). 48-hour experimental runs were also carried out to further investigate the mode of action of D-Phe. It was found that the difference between cytotoxicity levels of control cells and protected cells was higher over longer time. (author)

  18. DRAM triggers lysosomal membrane permeabilization and cell death in CD4(+ T cells infected with HIV.

    Directory of Open Access Journals (Sweden)

    Mireille Laforge

    Full Text Available Productive HIV infection of CD4(+ T cells leads to a caspase-independent cell death pathway associated with lysosomal membrane permeabilization (LMP and cathepsin release, resulting in mitochondrial outer membrane permeabilization (MOMP. Herein, we demonstrate that HIV infection induces damage-regulated autophagy modulator (DRAM expression in a p53-dependent manner. Knocking down the expression of DRAM and p53 genes with specific siRNAs inhibited autophagy and LMP. However, inhibition of Atg5 and Beclin genes that prevents autophagy had a minor effect on LMP and cell death. The knock down of DRAM gene inhibited cytochrome C release, MOMP and cell death. However, knocking down DRAM, we increased viral infection and production. Our study shows for the first time the involvement of DRAM in host-pathogen interactions, which may represent a mechanism of defense via the elimination of infected cells.

  19. Yessotoxin as a Tool to Study Induction of Multiple Cell Death Pathways

    Directory of Open Access Journals (Sweden)

    Mónica Suárez Korsnes

    2012-07-01

    Full Text Available This work proposes to use the marine algal toxin yessotoxin (YTX to establish reference model experiments to explore medically valuable effects from induction of multiple cell death pathways. YTX is one of few toxins reported to make such induction. It is a small molecule compound which at low concentrations can induce apoptosis in primary cultures, many types of cells and cell lines. It can also induce a non-apoptotic form of programmed cell death in BC3H1 myoblast cell lines. The present contribution reviews arguments that this type of induction may have principal interest outside this particular example. One principal effect of medical interest may be that cancer cells will not so easily adapt to the synergistic effects from induction of more than one death pathway as compared to induction of only apoptosis.

  20. Glutathione peroxidase 4 overexpression inhibits ROS-induced cell death in diffuse large B-cell lymphoma.

    Science.gov (United States)

    Kinowaki, Yuko; Kurata, Morito; Ishibashi, Sachiko; Ikeda, Masumi; Tatsuzawa, Anna; Yamamoto, Masahide; Miura, Osamu; Kitagawa, Masanobu; Yamamoto, Kouhei

    2018-02-20

    Regulation of oxidative stress and redox systems has important roles in carcinogenesis and cancer progression, and for this reason has attracted much attention as a new area of cancer therapeutic targets. Glutathione peroxidase 4 (GPX4), an antioxidant enzyme, has biological important functions such as signaling cell death by suppressing peroxidation of membrane phospholipids. However, few studies exist on the expression and clinical relevance of GPX4 in malignant lymphomas such as diffuse large B-cell lymphoma. In this study, we assessed the expression of GPX4 immunohistochemically. GPX4 was expressed in 35.5% (33/93) cases of diffuse large B-cell lymphoma. The GPX4-positive group had poor overall survival (P = 0.0032) and progression-free survival (P = 0.0004) compared with those of the GPX4-negative group. In a combined analysis of GPX4 and 8-hydroxydeoxyguanosine (8-OHdG), an oxidative stress marker, there was a negative correlation between GPX4 and 8-hydroxydeoxyguanosine (P = 0.0009). The GPX4-positive and 8-hydroxydeoxyguanosine-negative groups had a significantly worse prognosis than the other groups in both overall survival (P = 0.0170) and progression-free survival (P = 0.0005). These results suggest that the overexpression of GPX4 is an independent prognostic predictor in diffuse large B-cell lymphoma. Furthermore, in vitro analysis demonstrated that GPX4-overexpressing cells were resistant to reactive oxygen species-induced cell death (P = 0.0360). Conversely, GPX4-knockdown cells were sensitive to reactive oxygen species-induced cell death (P = 0.0111). From these data, we conclude that GPX4 regulates reactive oxygen species-induced cell death. Our results suggest a novel therapeutic strategy using the mechanism of ferroptosis, as well as a novel prognostic predictor of diffuse large B-cell lymphoma.

  1. Blockade of maitotoxin-induced oncotic cell death reveals zeiosis

    Directory of Open Access Journals (Sweden)

    Schilling William P

    2002-01-01

    Full Text Available Abstract Background Maitotoxin (MTX initiates cell death by sequentially activating 1 Ca2+ influx via non-selective cation channels, 2 uptake of vital dyes via formation of large pores, and 3 release of lactate dehydrogenase, an indication of cell lysis. MTX also causes formation of membrane blebs, which dramatically dilate during the cytolysis phase. To determine the role of phospholipase C (PLC in the cell death cascade, U73122, a specific inhibitor of PLC, and U73343, an inactive analog, were examined on MTX-induced responses in bovine aortic endothelial cells. Results Addition of either U73122 or U73343, prior to MTX, produced a concentration-dependent inhibition of the cell death cascade (IC50 ≈ 1.9 and 0.66 μM, respectively suggesting that the effect of these agents was independent of PLC. Addition of U73343 shortly after MTX, prevented or attenuated the effects of the toxin, but addition at later times had little or no effect. Time-lapse videomicroscopy showed that U73343 dramatically altered the blebbing profile of MTX-treated cells. Specifically, U73343 blocked bleb dilation and converted the initial blebbing event into "zeiosis", a type of membrane blebbing commonly associated with apoptosis. Cells challenged with MTX and rescued by subsequent addition of U73343, showed enhanced caspase-3 activity 48 hr after the initial insult, consistent with activation of the apoptotic program. Conclusions Within minutes of MTX addition, endothelial cells die by oncosis. Rescue by addition of U73343 shortly after MTX showed that a small percentage of cells are destined to die by oncosis, but that a larger percentage survive; cells that survive the initial insult exhibit zeiosis and may ultimately die by apoptotic mechanisms.

  2. The Neurofibromatosis 2 Tumor Suppressor Gene Product, Merlin, Regulates Human Meningioma Cell Growth by Signaling through YAP

    Directory of Open Access Journals (Sweden)

    Katherine Striedinger

    2008-11-01

    Full Text Available Neurofibromatosis type 2 (NF2 is an autosomal dominant disorder characterized by the occurrence of schwannomas and meningiomas. Several studies have examined the ability of the NF2 gene product, merlin, to function as a tumor suppressor in diverse cell types; however, little is known about merlin growth regulation in meningiomas. In Drosophila, merlin controls cell proliferation and apoptosis by signaling through the Hippo pathway to inhibit the function of the transcriptional coactivator Yorkie. The Hippo pathway is conserved in mammals. On the basis of these observations, we developed human meningioma cell lines matched for merlin expression to evaluate merlin growth regulation and investigate the relationship between NF2 status and Yes-associated protein (YAP, the mammalian homolog of Yorkie. NF2 loss in meningioma cells was associated with loss of contact-dependent growth inhibition, enhanced anchorage-independent growth and increased cell proliferation due to increased S-phase entry. In addition, merlin loss in both meningioma cell lines and primary tumors resulted in increased YAP expression and nuclear localization. Finally, siRNA-mediated reduction of YAP in NF2-deficient meningioma cells rescued the effects of merlin loss on cell proliferation and S-phase entry. Collectively, these results represent the first demonstration that merlin regulates cell growth in human cancer cells by suppressing YAP.

  3. Intracellular cholesterol level regulates sensitivity of glioblastoma cells against temozolomide-induced cell death by modulation of caspase-8 activation via death receptor 5-accumulation and activation in the plasma membrane lipid raft.

    Science.gov (United States)

    Yamamoto, Yutaro; Tomiyama, Arata; Sasaki, Nobuyoshi; Yamaguchi, Hideki; Shirakihara, Takuya; Nakashima, Katsuhiko; Kumagai, Kosuke; Takeuchi, Satoru; Toyooka, Terushige; Otani, Naoki; Wada, Kojiro; Narita, Yoshitaka; Ichimura, Koichi; Sakai, Ryuichi; Namba, Hiroki; Mori, Kentaro

    2018-01-01

    Development of resistance against temozolomide (TMZ) in glioblastoma (GBM) after continuous treatment with TMZ is one of the critical problems in clinical GBM therapy. Intracellular cholesterol regulates cancer cell biology, but whether intracellular cholesterol is involved in TMZ resistance of GBM cells remains unclear. The involvement of intracellular cholesterol in acquired resistance against TMZ in GBM cells was investigated. Intracellular cholesterol levels were measured in human U251 MG cells with acquired TMZ resistance (U251-R cells) and TMZ-sensitive control U251 MG cells (U251-Con cells), and found that the intracellular cholesterol level was significantly lower in U251-R cells than in U251-Con cells. In addition, treatment by intracellular cholesterol remover, methyl-beta cyclodextrin (MβCD), or intracellular cholesterol inducer, soluble cholesterol (Chol), regulated TMZ-induced U251-Con cell death in line with changes in intracellular cholesterol level. Involvement of death receptor 5 (DR5), a death receptor localized in the plasma membrane, was evaluated. TMZ without or with MβCD and/or Chol caused accumulation of DR5 into the plasma membrane lipid raft and formed a complex with caspase-8, an extrinsic caspase cascade inducer, reflected in the induction of cell death. In addition, treatment with caspase-8 inhibitor or knockdown of DR5 dramatically suppressed U251-Con cell death induced by combination treatment with TMZ, MβCD, and Chol. Combined treatment of Chol with TMZ reversed the TMZ resistance of U251-R cells and another GBM cell model with acquired TMZ resistance, whereas clinical antihypercholesterolemia agents at physiological concentrations suppressed TMZ-induced cell death of U251-Con cells. These findings suggest that intracellular cholesterol level affects TMZ treatment of GBM mediated via a DR5-caspase-8 mechanism. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. BH3-mimetics- and cisplatin-induced cell death proceeds through different pathways depending on the availability of death-related cellular components.

    Directory of Open Access Journals (Sweden)

    Vicente Andreu-Fernández

    Full Text Available BACKGROUND: Owing to their important function in regulating cell death, pharmacological inhibition of Bcl-2 proteins by dubbed BH3-mimetics is a promising strategy for apoptosis induction or sensitization to chemotherapy. However, the role of Apaf-1, the main protein constituent of the apoptosome, in the process has yet not been analyzed. Furthermore as new chemotherapeutics develop, the possible chemotherapy-induced toxicity to rapidly dividing normal cells, especially sensitive differentiated cells, has to be considered. Such undesirable effects would probably be ameliorated by selectively and locally inhibiting apoptosis in defined sensitive cells. METHODOLOGY AND PRINCIPAL FINDINGS: Mouse embryonic fibroblasts (MEFS from Apaf-1 knock out mouse (MEFS KO Apaf-1 and Bax/Bak double KO (MEFS KO Bax/Bak, MEFS from wild-type mouse (MEFS wt and human cervix adenocarcinoma (HeLa cells were used to comparatively investigate the signaling cell death-induced pathways of BH3-mimetics, like ABT737 and GX15-070, with DNA damage-inducing agent cisplatin (cis-diammineplatinum(II dichloride, CDDP. The study was performed in the absence or presence of apoptosis inhibitors namely, caspase inhibitors or apoptosome inhibitors. BH3-mimetic ABT737 required of Apaf-1 to exert its apoptosis-inducing effect. In contrast, BH3-mimetic GX15-070 and DNA damage-inducing CDDP induced cell death in the absence of both Bax/Bak and Apaf-1. GX15-070 induced autophagy-based cell death in all the cell lines analyzed. MEFS wt cells were protected from the cytotoxic effects of ABT737 and CDDP by chemical inhibition of the apoptosome through QM31, but not by using general caspase inhibitors. CONCLUSIONS: BH3-mimetic ABT737 not only requires Bax/Bak to exert its apoptosis-inducing effect, but also Apaf-1, while GX15-070 and CDDP induce different modalities of cell death in the absence of Bax/Bak or Apaf-1. Inclusion of specific Apaf-1 inhibitors in topical and well

  5. LMP1-mediated glycolysis induces myeloid-derived suppressor cell expansion in nasopharyngeal carcinoma.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Cai

    2017-07-01

    Full Text Available Myeloid-derived suppressor cells (MDSCs are expanded in tumor microenvironments, including that of Epstein-Barr virus (EBV-associated nasopharyngeal carcinoma (NPC. The link between MDSC expansion and EBV infection in NPC is unclear. Here, we show that EBV latent membrane protein 1 (LMP1 promotes MDSC expansion in the tumor microenvironment by promoting extra-mitochondrial glycolysis in malignant cells, which is a scenario for immune escape initially suggested by the frequent, concomitant detection of abundant LMP1, glucose transporter 1 (GLUT1 and CD33+ MDSCs in tumor sections. The full process has been reconstituted in vitro. LMP1 promotes the expression of multiple glycolytic genes, including GLUT1. This metabolic reprogramming results in increased expression of the Nod-like receptor family protein 3 (NLRP3 inflammasome, COX-2 and P-p65 and, consequently, increased production of IL-1β, IL-6 and GM-CSF. Finally, these changes in the environment of malignant cells result in enhanced NPC-derived MDSC induction. One key step is the physical interaction of LMP1 with GLUT1 to stabilize the GLUT1 protein by blocking its K48-ubiquitination and p62-dependent autolysosomal degradation. This work indicates that LMP1-mediated glycolysis regulates IL-1β, IL-6 and GM-CSF production through the NLRP3 inflammasome, COX-2 and P-p65 signaling pathways to enhance tumor-associated MDSC expansion, which leads to tumor immunosuppression in NPC.

  6. Rip3 knockdown rescues photoreceptor cell death in blind pde6c zebrafish.

    Science.gov (United States)

    Viringipurampeer, I A; Shan, X; Gregory-Evans, K; Zhang, J P; Mohammadi, Z; Gregory-Evans, C Y

    2014-05-01

    Achromatopsia is a progressive autosomal recessive retinal disease characterized by early loss of cone photoreceptors and later rod photoreceptor loss. In most cases, mutations have been identified in CNGA3, CNGB3, GNAT2, PDE6C or PDE6H genes. Owing to this genetic heterogeneity, mutation-independent therapeutic schemes aimed at preventing cone cell death are very attractive treatment strategies. In pde6c(w59) mutant zebrafish, cone photoreceptors expressed high levels of receptor-interacting protein kinase 1 (RIP1) and receptor-interacting protein kinase 3 (RIP3) kinases, key regulators of necroptotic cell death. In contrast, rod photoreceptor cells were alternatively immunopositive for caspase-3 indicating activation of caspase-dependent apoptosis in these cells. Morpholino gene knockdown of rip3 in pde6c(w59) embryos rescued the dying cone photoreceptors by inhibiting the formation of reactive oxygen species and by inhibiting second-order neuron remodelling in the inner retina. In rip3 morphant larvae, visual function was restored in the cones by upregulation of the rod phosphodiesterase genes (pde6a and pde6b), compensating for the lack of cone pde6c suggesting that cones are able to adapt to their local environment. Furthermore, we demonstrated through pharmacological inhibition of RIP1 and RIP3 activity that cone cell death was also delayed. Collectively, these results demonstrate that the underlying mechanism of cone cell death in the pde6c(w59) mutant retina is through necroptosis, whereas rod photoreceptor bystander death occurs through a caspase-dependent mechanism. This suggests that targeting the RIP kinase signalling pathway could be an effective therapeutic intervention in retinal degeneration patients. As bystander cell death is an important feature of many retinal diseases, combinatorial approaches targeting different cell death pathways may evolve as an important general principle in treatment.

  7. E-Cigarette Aerosol Exposure Induces Reactive Oxygen Species, DNA Damage, and Cell Death in Vascular Endothelial Cells.

    Science.gov (United States)

    Anderson, Chastain; Majeste, Andrew; Hanus, Jakub; Wang, Shusheng

    2016-12-01

    Cigarette smoking remains one of the leading causes of preventable death worldwide. Vascular cell death and dysfunction is a central or exacerbating component in the majority of cigarette smoking related pathologies. The recent development of the electronic nicotine delivery systems known as e-cigarettes provides an alternative to conventional cigarette smoking; however, the potential vascular health risks of e-cigarette use remain unclear. This study evaluates the effects of e-cigarette aerosol extract (EAE) and conventional cigarette smoke extract (CSE) on human umbilical vein endothelial cells (HUVECs). A laboratory apparatus was designed to produce extracts from e-cigarettes and conventional cigarettes according to established protocols for cigarette smoking. EAE or conventional CSE was applied to human vascular endothelial cells for 4-72 h, dependent on the assay. Treated cells were assayed for reactive oxygen species, DNA damage, cell viability, and markers of programmed cell death pathways. Additionally, the anti-oxidants α-tocopherol and n-acetyl-l-cysteine were used to attempt to rescue e-cigarette induced cell death. Our results indicate that e-cigarette aerosol is capable of inducing reactive oxygen species, causing DNA damage, and significantly reducing cell viability in a concentration dependent fashion. Immunofluorescent and flow cytometry analysis indicate that both the apoptosis and programmed necrosis pathways are triggered by e-cigarette aerosol treatment. Additionally, anti-oxidant treatment provides a partial rescue of the induced cell death, indicating that reactive oxygen species play a causal role in e-cigarette induced cytotoxicity. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Gemfibrozil, a Lipid-lowering Drug, Induces Suppressor of Cytokine Signaling 3 in Glial Cells

    Science.gov (United States)

    Ghosh, Arunava; Pahan, Kalipada

    2012-01-01

    Glial inflammation is an important feature of several neurodegenerative disorders. Suppressor of cytokine signaling (SOCS) proteins play a crucial role in inhibiting cytokine signaling and inflammatory gene expression in various cell types, including glial cells. However, mechanisms by which SOCS genes could be up-regulated are poorly understood. This study underlines the importance of gemfibrozil, a Food and Drug Administration-approved lipid-lowering drug, in up-regulating the expression of SOCS3 in glial cells. Gemfibrozil increased the expression of Socs3 mRNA and protein in mouse astroglia and microglia in both a time- and dose-dependent manner. Interestingly, gemfibrozil induced the activation of type IA phosphatidylinositol (PI) 3-kinase and AKT. Accordingly, inhibition of PI 3-kinase and AKT by chemical inhibitors abrogated gemfibrozil-mediated up-regulation of SOCS3. Furthermore, we demonstrated that gemfibrozil induced the activation of Krüppel-like factor 4 (KLF4) via the PI 3-kinase-AKT pathway and that siRNA knockdown of KLF4 abrogated gemfibrozil-mediated up-regulation of SOCS3. Gemfibrozil also induced the recruitment of KLF4 to the distal, but not proximal, KLF4-binding site of the Socs3 promoter. This study delineates a novel property of gemfibrozil in up-regulating SOCS3 in glial cells via PI 3-kinase-AKT-mediated activation of KLF4 and suggests that gemfibrozil may find therapeutic application in neuroinflammatory and neurodegenerative disorders. PMID:22685291

  9. Retinoid-induced expression and activity of an immediate early tumor suppressor gene in vascular smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Jeffrey W Streb

    2011-04-01

    Full Text Available Retinoids are used clinically to treat a number of hyper-proliferative disorders and have been shown in experimental animals to attenuate vascular occlusive diseases, presumably through nuclear receptors bound to retinoic acid response elements (RARE located in target genes. Here, we show that natural or synthetic retinoids rapidly induce mRNA and protein expression of a specific isoform of A-Kinase Anchoring Protein 12 (AKAP12β in cultured smooth muscle cells (SMC as well as the intact vessel wall. Expression kinetics and actinomycin D studies indicate Akap12β is a retinoid-induced, immediate-early gene. Akap12β promoter analyses reveal a conserved RARE mildly induced with atRA in a region that exhibits hyper-acetylation. Immunofluorescence microscopy and protein kinase A (PKA regulatory subunit overlay assays in SMC suggest a physical association between AKAP12β and PKA following retinoid treatment. Consistent with its designation as a tumor suppressor, inducible expression of AKAP12β attenuates SMC growth in vitro. Further, immunohistochemistry studies establish marked decreases in AKAP12 expression in experimentally-injured vessels of mice as well as atheromatous lesions in humans. Collectively, these results demonstrate a novel role for retinoids in the induction of an AKAP tumor suppressor that blocks vascular SMC growth thus providing new molecular insight into how retiniods may exert their anti-proliferative effects in the injured vessel wall.

  10. The cell on the edge of life and death: Crosstalk between autophagy and apoptosis.

    Science.gov (United States)

    Kasprowska-Liśkiewicz, Daniela

    2017-09-21

    Recently, the crosstalk between autophagy and apoptosis has attracted broader attention. Basal autophagy serves to maintain cell homeostasis, while the upregulation of this process is an element of stress response that enables the cell to survive under adverse conditions. Autophagy may also determine the fate of the cell through its interactions with cell death pathways. The protein networks that control the initiation and the execution phase of these two processes are highly interconnected. Several scenarios for the crosstalk between autophagy and apoptosis exist. In most cases, the activation of autophagy represents an attempt of the cell to cope with stress, and protects the cell from apoptosis or delays its initiation. Generally, the simultaneous activation of pro-survival and pro-death pathways is prevented by the mutual inhibitory crosstalk between autophagy and apoptosis. But in some circumstances, autophagy or the proteins of the core autophagic machinery may promote cellular demise through excessive self-digestion (so-called "autophagic cell death") or by stimulating the activation of other cell death pathways. It is controversial whether cells actually die via autophagy, which is why the term "autophagic cell death" has been under intense debate lately. This review summarizes the recent findings on the multilevel crosstalk between autophagy and apoptosis in aspects of common regulators, mutual inhibition of these processes, the stimulation of apoptosis by autophagy or autophagic proteins and finally the role of autophagy as a death-execution mechanism.

  11. Increased mast cell tryptase in sudden infant death - anaphylaxis, hypoxia or artefact?

    Science.gov (United States)

    Edston, E; Gidlund, E; Wickman, M; Ribbing, H; Van Hage-Hamsten, M

    1999-12-01

    Increased concentrations of mast cell tryptase in post mortem blood have frequently been observed in sudden infant deaths but the cause of this has not yet been clarified. The aim was to evaluate factors (immunological, morphological and anamnestic data) behind the observed increase in mast cell tryptase in sudden infant deaths with elevated tryptase. Mast cell tryptase and total immunoglobulin (Ig) E were measured in post mortem sera from 44 infants younger than 1.5 years. Radioallergosorbent tests were performed for possible allergens (mixture for relevant food allergens, Phadiatop and latex). IgG subclasses, IgM, and complement factors (C3, C4 and factor B) were measured with radial immunodiffusion. Mast cells, labelled with antibodies against mast cell tryptase, were counted in the lungs and heart. The circumstances of death and medical history of the deceased infant and family were obtained through police and hospital records. In 40% of the SIDS cases tryptase was elevated (>10 microg/L). Total IgE in serum was increased in 33% compared with clinical reference values but showed no association with mast cell tryptase. RAST tests were positive in three cases. In one of these cases both tryptase and total IgE were elevated. The only variable that was associated with high tryptase values was prone position at death (P Children with elevated total IgE also displayed high concentrations of IgG1 and IgG2. Infants who died in the spring had significantly higher IgE than the others (P < or = 0.05). The results do not support the hypothesis that the elevated tryptase concentrations in sudden infant death are caused by allergy. The association between prone position at death and elevated tryptase could hypothetically be explained by mast cell degranulation due to, for example, a hypoxic stimulus in these infants.

  12. Secretory phospholipase A2-mediated neuronal cell death involves glutamate ionotropic receptors

    DEFF Research Database (Denmark)

    Kolko, Miriam; de Turco, Elena B; Diemer, Nils Henrik

    2002-01-01

    To define the significance of glutamate ionotropic receptors in sPLA -mediated neuronal cell death we used the NMDA receptor antagonist MK-801 and the AMPA receptor antagonist PNQX. In primary neuronal cell cultures both MK-801 and PNQX inhibited sPLA - and glutamate-induced neuronal death. [ H...

  13. Rational development of a cytotoxic peptide to trigger cell death.

    Science.gov (United States)

    Boohaker, Rebecca J; Zhang, Ge; Lee, Michael W; Nemec, Kathleen N; Santra, Santimukul; Perez, J Manuel; Khaled, Annette R

    2012-07-02

    Defects in the apoptotic machinery can contribute to tumor formation and resistance to treatment, creating a need to identify new agents that kill cancer cells by alternative mechanisms. To this end, we examined the cytotoxic properties of a novel peptide, CT20p, derived from the C-terminal, alpha-9 helix of Bax, an amphipathic domain with putative membrane binding properties. Like many antimicrobial peptides, CT20p contains clusters of hydrophobic and cationic residues that could enable the peptide to associate with lipid membranes. CT20p caused the release of calcein from mitochondrial-like lipid vesicles without disrupting vesicle integrity and, when expressed as a fusion protein in cells, localized to mitochondria. The amphipathic nature of CT20p allowed it to be encapsulated in polymeric nanoparticles (NPs) that have the capacity to harbor targeting molecules, dyes or drugs. The resulting CT20p-NPs proved an effective killer, in vitro, of colon and breast cancer cells, and in vivo, using a murine breast cancer tumor model. By introducing CT20p to Bax deficient cells, we demonstrated that the peptide's lethal activity was independent of endogenous Bax. CT20p also caused an increase in the mitochondrial membrane potential that was followed by plasma membrane rupture and cell death, without the characteristic membrane asymmetry associated with apoptosis. We determined that cell death triggered by the CT20p-NPs was minimally dependent on effector caspases and resistant to Bcl-2 overexpression, suggesting that it acts independently of the intrinsic apoptotic death pathway. Furthermore, use of CT20p with the apoptosis-inducing drug, cisplatin, resulted in additive toxicity. These results reveal the novel features of CT20p that allow nanoparticle-mediated delivery to tumors and the potential application in combination therapies to activate multiple death pathways in cancer cells.

  14. Gene expression analysis of cell death induction by Taurolidine in different malignant cell lines

    International Nuclear Information System (INIS)

    Chromik, Ansgar M; Weyhe, Dirk; Mittelkötter, Ulrich; Uhl, Waldemar; Hahn, Stephan A; Daigeler, Adrien; Flier, Annegret; Bulut, Daniel; May, Christina; Harati, Kamran; Roschinsky, Jan; Sülberg, Dominique

    2010-01-01

    The anti-infective agent Taurolidine (TRD) has been shown to have cell death inducing properties, but the mechanism of its action is largely unknown. The aim of this study was to identify potential common target genes modulated at the transcriptional level following TRD treatment in tumour cell lines originating from different cancer types. Five different malignant cell lines (HT29, Chang Liver, HT1080, AsPC-1 and BxPC-3) were incubated with TRD (100 μM, 250 μM and 1000 μM). Proliferation after 8 h and cell viability after 24 h were analyzed by BrdU assay and FACS analysis, respectively. Gene expression analyses were carried out using the Agilent -microarray platform to indentify genes which displayed conjoint regulation following the addition of TRD in all cell lines. Candidate genes were subjected to Ingenuity Pathways Analysis and selected genes were validated by qRT-PCR and Western Blot. TRD 250 μM caused a significant inhibition of proliferation as well as apoptotic cell death in all cell lines. Among cell death associated genes with the strongest regulation in gene expression, we identified pro-apoptotic transcription factors (EGR1, ATF3) as well as genes involved in the ER stress response (PPP1R15A), in ubiquitination (TRAF6) and mitochondrial apoptotic pathways (PMAIP1). This is the first conjoint analysis of potential target genes of TRD which was performed simultaneously in different malignant cell lines. The results indicate that TRD might be involved in different signal transduction pathways leading to apoptosis

  15. Tumor necrosis factor (TNF) biology and cell death.

    Science.gov (United States)

    Bertazza, Loris; Mocellin, Simone

    2008-01-01

    Tumor necrosis factor (TNF) was the first cytokine to be used in humans for cancer therapy. However, its role in the treatment of cancer patients is debated. Most uncertainties in this field stem from the knowledge that the pathways directly activated or indirectly affected upon TNF engagement with its receptors can ultimately lead to very different outcomes in terms of cell survival. In this article, we summarize the fundamental molecular biology aspects of this cytokine. Such a basis is a prerequisite to critically approach the sometimes conflicting preclinical and clinical findings regarding the relationship between TNF, tumor biology and anticancer therapy. Although the last decade has witnessed remarkable advances in this field, we still do not know in detail how cells choose between life and death after TNF stimulation. Understanding this mechanism will not only shed new light on the physiological significance of TNF-driven programmed cell death but also help investigators maximize the anticancer potential of this cytokine.

  16. Induction of cell death by graphene in Arabidopsis thaliana (Columbia ecotype) T87 cell suspensions

    International Nuclear Information System (INIS)

    Begum, Parvin; Fugetsu, Bunshi

    2013-01-01

    Highlights: • This study was set up to explore potential influence of graphene on T87 cells. • Fragmented nuclei, membrane damage, mitochondrial dysfunction were observed. • ROS increased, ROS are key mediators in the cell death signaling pathway. • Translocation of graphene into cells and an endocytosis-like structure was observed. • Graphene entering into the cells by endocytosis. -- Abstract: The toxicity of graphene on suspensions of Arabidopsis thaliana (Columbia ecotype) T87 cells was investigated by examining the morphology, mitochondrial dysfunction, reactive oxygen species generation (ROS), and translocation of graphene as the toxicological endpoints. The cells were grown in Jouanneau and Péaud-Lenoel (JPL) media and exposed to graphene at concentrations 0–80 mg/L. Morphological changes were observed by scanning electron microscope and the adverse effects such as fragmented nuclei, membrane damage, mitochondrial dysfunction was observed with fluorescence microscopy by staining with Hoechst 33342/propidium iodide and succinate dehydrogenase (mitochondrial bioenergetic enzyme). Analysis of intracellular ROS by 2′,7′-dichlorofluorescein diacetate demonstrated that graphene induced a 3.3-fold increase in ROS, suggesting that ROS are key mediators in the cell death signaling pathway. Transmission electron microscopy verified the translocation of graphene into cells and an endocytosis-like structure was observed which suggested graphene entering into the cells by endocytosis. In conclusion, our results show that graphene induced cell death in T87 cells through mitochondrial damage mediated by ROS

  17. MicroRNAs as tumour suppressors in canine and human melanoma cells and as a prognostic factor in canine melanomas.

    Science.gov (United States)

    Noguchi, S; Mori, T; Hoshino, Y; Yamada, N; Maruo, K; Akao, Y

    2013-06-01

    Malignant melanoma (MM) is one of the most aggressive cancers in dogs and in humans. However, the molecular mechanisms of its development and progression remain unclear. Presently, we examined the expression profile of microRNAs (miRs) in canine oral MM tissues and paired normal oral mucosa tissues by using the microRNA-microarray assay and quantitative RT-PCR. Importantly, a decreased expression of miR-203 was significantly associated with a shorter survival time. Also, miR-203 and -205 were markedly down-regulated in canine and human MM cell lines tested. Furthermore, the ectopic expression of miR-205 had a significant inhibitory effect on the cell growth of canine and human melanoma cells tested by targeting erbb3. Our data suggest that miR-203 is a new prognostic factor in canine oral MMs and that miR-205 functions as a tumour suppressor by targeting erbb3 in both canine and human MM cells. © 2011 John Wiley & Sons Ltd.

  18. Delayed reproductive death as a dominant phenotype in cell clones surviving X-irradiation

    International Nuclear Information System (INIS)

    Chang, W.P.; Little, J.B.

    1992-01-01

    Residual damage manifested as reduced cloning efficiency was observed in many of the cloned progeny of Chinese hamster ovary (CHO) cells and human carcinoma SQ-20B cells surviving X-irradiation. This stable phenotype, which we have termed delayed reproductive death, persisted for >50 generations of cell replication post-irradiation. Clones showing this phenotype were aneuploid, and formed colonies with a high proportion of giant cells. By somatic cell hybridization of CHO clones, the delayed reproductive death phenotype was found to be a dominant trait; the cloning efficiency of hybrid clones was persistently depressed, as compared with that of control hybrid cells. These results suggest that delayed reproductive death represents a specific cellular response that may persist in some of the progeny of mammalian cells for long periods after X-irradiation. (author)

  19. Methyl Vitamin B12 but not methylfolate rescues a motor neuron-like cell line from homocysteine-mediated cell death

    International Nuclear Information System (INIS)

    Hemendinger, Richelle A.; Armstrong, Edward J.; Brooks, Benjamin Rix

    2011-01-01

    Homocysteine is an excitatory amino acid implicated in multiple diseases including amyotrophic lateral sclerosis (ALS). Information on the toxicity of homocysteine in motor neurons is limited and few studies have examined how this toxicity can be modulated. In NSC-34D cells (a hybrid cell line derived from motor neuron-neuroblastoma), homocysteine induces apoptotic cell death in the millimolar range with a TC 50 (toxic concentration at which 50% of maximal cell death is achieved) of 2.2 mM, confirmed by activation of caspase 3/7. Induction of apoptosis was independent of short-term reactive oxygen species (ROS) generation. Methyl Vitamin B12 (MeCbl) and methyl tetrahydrofolate (MTHF), used clinically to treat elevated homocysteine levels, were tested for their ability to reverse homocysteine-mediated motor neuron cell death. MeCbl in the micromolar range was able to provide neuroprotection (2 h pretreatment prior to homocysteine) and neurorescue (simultaneous exposure with homocysteine) against millimolar homocysteine with an IC 50 (concentration at which 50% of maximal cell death is inhibited) of 0.6 μM and 0.4 μM, respectively. In contrast, MTHF (up to 10 μM) had no effect on homocysteine-mediated cell death. MeCbl inhibited caspase 3/7 activation by homocysteine in a time- and dose-dependent manner, whereas MTHF had no effect. We conclude that MeCbl is effective against homocysteine-induced cell death in motor neurons in a ROS-independent manner, via a reduction in caspase activation and apoptosis. MeCbl decreases Hcy induced motor neuron death in vitro in a hybrid cell line derived from motor neuron-neuroblastoma and may play a role in the treatment of late stage ALS where HCy levels are increased in animal models of ALS.

  20. Bar represses dPax2 and decapentaplegic to regulate cell fate and morphogenetic cell death in Drosophila eye.

    Directory of Open Access Journals (Sweden)

    Jongkyun Kang

    Full Text Available The coordinated regulation of cell fate and cell survival is crucial for normal pattern formation in developing organisms. In Drosophila compound eye development, crystalline arrays of hexagonal ommatidia are established by precise assembly of diverse cell types, including the photoreceptor cells, cone cells and interommatidial (IOM pigment cells. The molecular basis for controlling the number of cone and IOM pigment cells during ommatidial pattern formation is not well understood. Here we present evidence that BarH1 and BarH2 homeobox genes are essential for eye patterning by inhibiting excess cone cell differentiation and promoting programmed death of IOM cells. Specifically, we show that loss of Bar from the undifferentiated retinal precursor cells leads to ectopic expression of Prospero and dPax2, two transcription factors essential for cone cell specification, resulting in excess cone cell differentiation. We also show that loss of Bar causes ectopic expression of the TGFβ homolog Decapentaplegic (Dpp posterior to the morphogenetic furrow in the larval eye imaginal disc. The ectopic Dpp expression is not responsible for the formation of excess cone cells in Bar loss-of-function mutant eyes. Instead, it causes reduction in IOM cell death in the pupal stage by antagonizing the function of pro-apoptotic gene reaper. Taken together, this study suggests a novel regulatory mechanism in the control of developmental cell death in which the repression of Dpp by Bar in larval eye disc is essential for IOM cell death in pupal retina.