Dataset Information

Helicobacter pylori sensitizes TNF-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in human gastric epithelial cells through regulation of FLIP.

ABSTRACT: Helicobacter pylori (H. pylori) infection is associated with chronic gastritis, peptic ulcer and gastric cancer. Apoptosis induced by microbial infections is implicated in the pathogenesis of H. pylori infection. Here we show that human gastric epithelial cells sensitized to H. pylori confer susceptibility to TRAIL-mediated apoptosis via modulation of death receptor signaling. Human gastric epithelial cells are intrinsically resistant to TRAIL-mediated apoptosis. The induction of TRAIL sensitivity by H. pylori is dependent on the activation of caspase-8 and its downstream pathway. H. pylori induces caspase-8 activation via enhanced assembly of the TRAIL death-inducing signaling complex (DISC) through downregulation of cellular FLICE-inhibitory protein (FLIP). Overexpression of FLIP abolished the H. pylori-induced TRAIL sensitivity in human gastric epithelial cells. Our study thus demonstrates that H. pylori induces sensitivity to TRAIL apoptosis by regulation of FLIP and assembly of DISC, which initiates caspase activation, resulting in the breakdown of resistance to apoptosis, and provides insight into the pathogenesis of gastric damage in Helicobacter infection. Modulation of host apoptosis signaling by bacterial interaction adds a new dimension to the pathogenesis of Helicobacter.

SUBMITTER: Lin WC

PROVIDER: S-EPMC3973194 | biostudies-other | 2014

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to be a potent inducer of apoptosis in various cancer cell lines and primary cancer cells. However, in clinical trials administration of recombinant TRAIL or TRAIL death receptor agonists did not show sufficient efficacy for treatment of tested malignant disorders compared to standard chemotherapy. Acquired resistance of cancer cells to TRAIL and to other âdeath receptorâ ligands may explain not only the inability of TRAIL and TRAIL âdeath receptorâ agonists to achieve the clearance of cancer cells in vivo but also the escape of cancer cells from immune cell â mediated killing. Selective pressure of TRAIL on TRAIL-sensitive Jurkat T-lymphoblastic leukemia cells provided several TRAIL resistant Jurkat cell line clones (TR1, TR2, TR3). We showed that acquired TRAIL resistance was associated with complex disruption of both extrinsic and intrinsic apoptotic pathways manifested by acquired multi-drug resistant phenotype of TR1, TR2, and TR3 clones. To identify changes associated with TRAIL resistance of Jurkat cells we performed genome-wide gene expression analysis of TRAIL-resistant clones (TR) and compared to WT Jurkat cells. We identified significantly increased expression (1.33-fold change with adjusted p < 0.05) of 73 genes in TR1 clone, 53 genes in TR2 clone and 8 genes in TR3 clone, and significant decrease in expression (0.75-fold change with adjusted p < 0.05) of 174 genes in TR1 clone, 36 genes in TR2 clone and 28 genes in TR3 clone. There was an overlap of only 2 significantly overexpressed (midkine / MDK and zinc finger and BTB domain containing 16 gene / ZBTB16 / PLZF) and 4 downregulated genes (YAP1, IGJ, EIF1AY, RPS4Y1) in all three TR clones. Total cellular RNA was isolated from biologic duplicates of untreated Jurkat cells (WT) and TRAIL resistant Jurkat cell line subclones (TR1, TR2, TR3) established by selective pressure of TRAIL 1000 ng/mL on Jurkat cells over the period of 12 weeks.

Project description:In this study, we subjected the phenomenon of fractional killing in a clonal population of TRAIL-sensitive cells to careful analysis. We asked whether cells that survive initial exposure to TRAIL are sensitive or resistant to subsequent treatment with TRAIL or other apoptosis-inducing agents. We observed that TRAIL survivor cells were highly resistant to a subsequent treatment with TRAIL 24hr later but that this resistance disappeared following several days in culture. Resistance did not involve downregulation of TRAIL receptors and extended to death ligands that bind different classes of receptors: TRAIL survivors were transiently resistant to FasL and vice versa. Gene expression analysis revealed that NF-kB-mediated inflammatory genes were activated in transiently resistant survivor cells leading to an inflammatory phenotype, but resistance was mediated by an independent mechanism related to changes in signaling at the DISC. Periodic exposure to TRAIL sustained resistance, demonstrating a component of induced survival signaling leading to transient acquired resistance to TRAIL. Based on these results we propose that TRAIL treatment leads to a transient adaptation in survivor cells that can be sustained in cells exposed to long-term TRAIL treatments, leading to acquired resistance. Minimizing the impact of cell-to-cell variability on TRAIL-mediated killing will thus require appropriate spacing of stimuli as well as the use of additional agents that inhibit pro-survival pathways. RNA was collected from Control (untreated) MCF10A cells, Survivors of TRAIL treatment (Day 1), Reset cells (survivors on Day 7), and Repeat cells (Survivors treated with TRAIL on 2 subsequent days). RNA was also collected from Control and Survivor MCF10A cells expressing an IKB-super-repressor construct (Addgene, Plasmid 15291; Boehm et al., 2007), or treated with caspase inhibitors. Three biological experiments were performed (on different days) with 1-2 replicates of each sample collected for each experiment. The total number of samples was 31, on 4 IlluminaRef8 BeadChips (one sample was from an unrelated experiment and was not included). The number of total replicates for each treatment is as follows: Control (7); Survivors (6); Reset (3); Repeat (3); Control-IKB-super-repressor (2); Survivors-IKB-super-repressor (2); Control-zVADinhibitor (2); Survivors-zVADinhibitor (2); Control-IETDinhibitor (2); Survivors-IETDinhibitor (2).

Dataset Information

Helicobacter pylori sensitizes TNF-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis in human gastric epithelial cells through regulation of FLIP.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure