A screen for suppressors of apoptosis identifies a novel gain of function mutation in drosphilia RAS1s

2007 ◽  
Vol 30 (4) ◽  
pp. 82
Author(s):  
C Gafuik ◽  
J Agapite ◽  
H Steller
Keyword(s):  
Cell Death ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Model Organisms ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Gain Of Function ◽  
Ras Oncogenes ◽  
Induced Apoptosis

Background: Apoptosis is a morphologically distinct, genetically programmed form of cell death that is evolutionarily highly conserved amongst multi-cellular eukaryotes. Correct regulation of apoptosis is critical for normal development and the prevention of diseases, such as cancer. Genetic analysis of invertebrate model organisms has proven invaluable for the identification and study of key molecules involved in apoptosis. In Drosophila, the proteins Reaper (Rpr), Head involution defective (Hid) and Grim induce cell death in a caspase dependent manner by inhibiting the anti-apoptotic function of diap1. Methods: To further elucidate the molecular mechanisms underlying the control of apoptosis, we conducted a dominant modifier screen for genes that could suppress the strong eye ablation phenotype caused by expressing hid under the control of an eye-specific promoter. Results: As previously reported, we identified several loss of function mutants in components of the EGFR/Ras/MAPK pathway that could dominantly suppress hid-induced apoptosis. These mutants proved to be alleles of either sprouty or gap1, two negative regulators of the RTK/Ras1 signaling. Here we report the identification and characterization of the first gain of function mutation in the Drosophila RAS1 gene. Conclusions: Taken together, these findings provide a molecular paradigm for the anti-apoptotic function of ras oncogenes.

scholarly journals Systematic genetic mapping of necroptosis identifies SLC39A7 as modulator of death receptor trafficking

2018 ◽  
Author(s):  
Astrid Fauster ◽  
Manuele Rebsamen ◽  
Katharina L. Willmann ◽  
Adrian César-Razquin ◽  
Enrico Girardi ◽  
...  
Keyword(s):  
Cell Death ◽  
Death Receptor ◽  
Receptor Trafficking ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Genetic Screens ◽  
Gain Of Function ◽  
Interacting Protein ◽  
Knock Out ◽  
Unbiased Gene

ABSTRACTRegulation of cell and tissue homeostasis by programmed cell death is a fundamental process with wide physiological and pathological implications. The advent of scalable somatic cell genetic technologies creates the opportunity to functionally map these essential pathways, thereby identifying potential disease-relevant components. We investigated the genetic basis underlying necroptotic cell death by performing a complementary set of loss- and gain-of-function genetic screens. To this end, we established FADD-deficient haploid human KBM7 cells, which specifically and efficiently undergo necroptosis after a single treatment with either TNFα or the SMAC mimetic compound birinapant. A series of unbiased gene-trap screens identified key signaling mediators, such as TNFR1, RIPK1, RIPK3, and MLKL. Among the novel components, we focused on the zinc transporter SLC39A7, whose knock-out led to necroptosis resistance by affecting TNF receptor trafficking and ER homeostasis. Orthogonal, solute carrier (SLC)-focused CRISPR/Cas9-based genetic screens revealed the exquisite specificity of SLC39A7, among ~ 400 SLC genes, for TNFR1- and FAS-but not TRAIL-R1-mediated responses. The newly established cellular model also allowed genome-wide gain-of-function screening for genes conferring resistance to necroptosis via the CRISPR/Cas9 synergistic activation mediator approach. Among these, we found cIAP1 and cIAP2, and characterized the role of TNIP1 (TNFAIP3-interacting protein 1), which prevented pathway activation in a ubiquitin-binding dependent manner. Altogether, the gain- and loss-of-function screens described here provide a global genetic chart of the molecular factors involved in necroptosis and death receptor signaling, prompting investigation of their individual contribution and potential role in pathological conditions.

Capsaicin mediates apoptosis in human nasopharyngeal carcinoma NPC-TW 039 cells through mitochondrial depolarization and endoplasmic reticulum stress

2011 ◽  
Vol 31 (6) ◽  
pp. 539-549 ◽  
Author(s):  
S-W Ip ◽  
S-H Lan ◽  
H-F Lu ◽  
A-C Huang ◽  
J-S Yang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Nasopharyngeal Carcinoma ◽  
Er Stress ◽  
Molecular Mechanisms ◽  
Human Cancer ◽  
Dependent Manner ◽  
Mitochondrial Depolarization ◽  
Human Nasopharyngeal Carcinoma ◽  
Induced Apoptosis

Capsaicin, a pungent compound found in hot chili peppers, has been reported to have antitumor activities in many human cancer cell lines, but the induction of precise apoptosis signaling pathway in human nasopharyngeal carcinoma (NPC) cells is unclear. Here, we investigated the molecular mechanisms of capsaicin-induced apoptosis in human NPC, NPC-TW 039, cells. Effects of capsaicin involved endoplasmic reticulum (ER) stress, caspase-3 activation and mitochondrial depolarization. Capsaicin-induced cytotoxic effects (cell death) through G0/G1 phase arrest and induction of apoptosis of NPC-TW 039 cells in a dose-dependent manner. Capsaicin treatment triggered ER stress by promoting the production of reactive oxygen species (ROS), increasing levels of inositol-requiring 1 enzyme (IRE1), growth arrest and DNA-damage-inducible 153 (GADD153) and glucose-regulated protein 78 (GRP78). Other effects included an increase in cytosolic Ca2+, loss of the mitochondrial transmembrane potential (ΔΨ m), releases of cytochrome c and apoptosis-inducing factor (AIF), and activation of caspase-9 and -3. Furthermore, capsaicin induced increases in the ratio of Bax/Bcl-2 and abundance of apoptosis-related protein levels. These results suggest that ER stress- and mitochondria-mediated cell death is involved in capsaicin-induced apoptosis in NPC-TW 039 cells.

scholarly journals A20 protects cells from TNF-induced apoptosis through linear ubiquitin-dependent and -independent mechanisms

2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Dario Priem ◽  
Michael Devos ◽  
Sarah Druwé ◽  
Arne Martens ◽  
Karolina Slowicka ◽  
...  
Keyword(s):  
Cell Death ◽  
Complex I ◽  
Molecular Mechanisms ◽  
Feedback Mechanism ◽  
Dependent Manner ◽  
Negative Feedback Mechanism ◽  
Signaling Complex ◽  
Induced Apoptosis

Abstract The cytokine TNF promotes inflammation either directly by activating the MAPK and NF-κB signaling pathways, or indirectly by triggering cell death. A20 is a potent anti-inflammatory molecule, and mutations in the gene encoding A20 are associated with a wide panel of inflammatory pathologies, both in human and in the mouse. Binding of TNF to TNFR1 triggers the NF-κB-dependent expression of A20 as part of a negative feedback mechanism preventing sustained NF-κB activation. Apart from acting as an NF-κB inhibitor, A20 is also well-known for its ability to counteract the cytotoxic potential of TNF. However, the mechanism by which A20 mediates this function and the exact cell death modality that it represses have remained incompletely understood. In the present study, we provide in vitro and in vivo evidences that deletion of A20 induces RIPK1 kinase-dependent and -independent apoptosis upon single TNF stimulation. We show that constitutively expressed A20 is recruited to TNFR1 signaling complex (Complex I) via its seventh zinc finger (ZF7) domain, in a cIAP1/2-dependent manner, within minutes after TNF sensing. We demonstrate that Complex I-recruited A20 protects cells from apoptosis by stabilizing the linear (M1) ubiquitin network associated to Complex I, a process independent of its E3 ubiquitin ligase and deubiquitylase (DUB) activities and which is counteracted by the DUB CYLD, both in vitro and in vivo. In absence of linear ubiquitylation, A20 is still recruited to Complex I via its ZF4 and ZF7 domains, but this time protects the cells from death by deploying its DUB activity. Together, our results therefore demonstrate two distinct molecular mechanisms by which constitutively expressed A20 protect cells from TNF-induced apoptosis.

The Bcl-2 proteins Noxa and Bcl-xL co-ordinately regulate oxidative stress-induced apoptosis

2012 ◽  
Vol 444 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Colins O. Eno ◽  
Guoping Zhao ◽  
Kristen E. Olberding ◽  
Chi Li
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Molecular Mechanisms ◽  
Myeloid Cell ◽  
Cell Leukaemia ◽  
Dependent Manner ◽  
Embryonic Fibroblasts ◽  
H2o2 Treatment ◽  
Apoptotic Activity ◽  
Induced Apoptosis

Because the detailed molecular mechanisms by which oxidative stress induces apoptosis are not completely known, we investigated how the complex Bcl-2 protein network might regulate oxidative stress-induced apoptosis. Using MEFs (mouse embryonic fibroblasts), we found that the endogenous anti-apoptotic Bcl-2 protein Bcl-xL prevented apoptosis initiated by H2O2. The BH3 (Bcl-2 homology 3)-only Bcl-2 protein Noxa was required for H2O2-induced cell death and was the single BH3-only Bcl-2 protein whose pro-apoptotic activity was completely antagonized by endogenous Bcl-xL. Upon H2O2 treatment, Noxa mRNA displayed the greatest increase among BH3-only Bcl-2 proteins. Expression levels of the anti-apoptotic Bcl-2 protein Mcl-1 (myeloid cell leukaemia sequence 1), the primary binding target of Noxa, were reduced in H2O2-treated cells in a Noxa-dependent manner, and Mcl-1 overexpression was able to prevent H2O2-induced cell death in Bcl-xL-deficient MEF cells. Importantly, reduction of the expression of both Mcl-1 and Bcl-xL caused spontaneous cell death. These studies reveal a signalling pathway in which H2O2 activates Noxa, leading to a decrease in Mcl-1 and subsequent cell death in the absence of Bcl-xL expression. The results of the present study indicate that both anti- and pro-apoptotic Bcl-2 proteins co-operate to regulate oxidative stress-induced apoptosis.

Poly-L-arginine: Enhancing Cytotoxicity and Cellular Uptake of Doxorubicin and Necrotic Cell Death

2019 ◽  
Vol 18 (10) ◽  
pp. 1448-1456 ◽  
Author(s):  
Bahareh Movafegh ◽  
Razieh Jalal ◽  
Zobeideh Mohammadi ◽  
Seyyede A. Aldaghi
Keyword(s):  
Cell Death ◽  
Cellular Uptake ◽  
Combined Treatment ◽  
Annexin V ◽  
Cell Penetrating Peptides ◽  
Short Exposure ◽  
Dependent Manner ◽  
Du145 Cells ◽  
Induced Apoptosis ◽  
Resistance To Doxorubicin

Objective: Cell resistance to doxorubicin and its toxicity to healthy tissue reduce its efficiency. The use of cell-penetrating peptides as drug delivery system along with doxorubicin is a strategy to reduce its side effects. In this study, the influence of poly-L-arginine on doxorubicin cytotoxicity, its cellular uptake and doxorubicin-induced apoptosis on human prostate cancer DU145 cells are assessed. Methods: The cytotoxicity of doxorubicin and poly-L-arginine, alone and in combination, in DU145 cells was evaluated at different exposure times using MTT assay. The influence of poly-L-arginine on doxorubicin delivery into cells was evaluated by fluorescence microscopy and ultraviolet spectroscopy. DAPI and ethidium bromide- acridine orange stainings, flow cytometry using annexin V/propidium iodide, western blot analysis with anti-p21 antibody and caspase-3 activity were used to examine the influence of poly-L-arginine on doxorubicininduced cell death. Results: Poly-L-arginine had no cytotoxicity at low concentrations and short exposure times. Poly-L-arginine increased the cytotoxic effect of doxorubicin in DU145 cells in a time-dependent manner. But no significant reduction was found in HFF cell viability. Poly-L-arginine seems to facilitate doxorubicin uptake and increase its intracellular concentration. 24h combined treatment of cells with doxorubicin (0.5 µM) and poly-L-arginine (1 µg ml-1) caused a small increase in doxorubicin-induced apoptosis and significantly elevated necrosis in DU145 cells as compared to each agent alone. Conclusion: Our results indicate that poly-L-arginine at lowest and highest concentrations act as proliferationinducing and antiproliferative agents, respectively. Between these concentrations, poly-L-arginine increases the cellular uptake of doxorubicin and its cytotoxicity through induction of necrosis.

VDAC1 Mediated Anticancer Activity of Gallic Acid in Human Lung Adenocarcinoma A549 Cells

2018 ◽  
Vol 18 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Aikebaier Maimaiti ◽  
Amier Aili ◽  
Hureshitanmu Kuerban ◽  
Xuejun Li
Keyword(s):  
Western Blot ◽  
Cell Viability ◽  
Gallic Acid ◽  
Molecular Mechanisms ◽  
A549 Cells ◽  
Dependent Manner ◽  
Lung Carcinoma Cells ◽  
Induced Apoptosis ◽  
The Impact

Aims: Gallic acid (GA) is generally distributed in a variety of plants and foods, and possesses cell growth-inhibiting activities in cancer cell lines. In the present study, the impact of GA on cell viability, apoptosis induction and possible molecular mechanisms in cultured A549 lung carcinoma cells was investigated. Methods: In vitro experiments showed that treating A549 cells with various concentrations of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA inhibits cell viability, comparative proteomic analysis was applied. The changed proteins were identified by Western blot and siRNA methods. Results: Two-dimensional electrophoresis revealed changes that occurred to the cells when treated with or without GA. Four up-regulated protein spots were clearly identified as malate dehydrogenase (MDH), voltagedependent, anion-selective channel protein 1(VDAC1), calreticulin (CRT) and brain acid soluble protein 1(BASP1). VDAC1 in A549 cells was reconfirmed by western blot. Transfection with VDAC1 siRNA significantly increased cell viability after the treatment of GA. Further investigation showed that GA down regulated PI3K/Akt signaling pathways. These data strongly suggest that up-regulation of VDAC1 by GA may play an important role in GA-induced, inhibitory effects on A549 cell viability.

scholarly journals Genetic and Molecular Characterization of the Caenorhabditis elegans Gene, mel-26, a Postmeiotic Negative Regulator of MEI-1, a Meiotic-Specific Spindle Component

Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 119-128
Author(s):  
M Rhys Dow ◽  
Paul E Mains
Keyword(s):  
Caenorhabditis Elegans ◽  
Protein Interactions ◽  
Negative Regulator ◽  
Meiotic Spindle ◽  
Loss Of Function ◽  
Protein Protein Interactions ◽  
Gain Of Function ◽  
Recessive Mutations ◽  
Female Germline

Abstract We have previously described the gene mei-1, which encodes an essential component of the Caenorhabditis elegans meiotic spindle. When ectopically expressed after the completion of meiosis, mei-1 protein disrupts the function of the mitotic cleavage spindles. In this article, we describe the cloning and the further genetic characterization of mel-26, a postmeiotic negative regulator of mei-1. mel-26 was originally identified by a gain-of-function mutation. We have reverted this mutation to a loss-of-function allele, which has recessive phenotypes identical to the dominant defects of its gain-of-function parent. Both the dominant and recessive mutations of mel-26 result in mei-1 protein ectopically localized in mitotic spindles and centrosomes, leading to small and misoriented cleavage spindles. The loss-of-function mutation was used to clone mel-26 by transformation rescue. As suggested by genetic results indicating that mel-26 is required only maternally, mel-26 mRNA was expressed predominantly in the female germline. The gene encodes a protein that includes the BTB motif, which is thought to play a role in protein-protein interactions.

scholarly journals Nonylphenol Induces Apoptosis through ROS/JNK Signaling in a Spermatogonia Cell Line

2020 ◽  
Vol 22 (1) ◽  
pp. 307
Author(s):  
Hyun-Jung Park ◽  
Ran Lee ◽  
Hyunjin Yoo ◽  
Kwonho Hong ◽  
Hyuk Song
Keyword(s):  
Molecular Mechanisms ◽  
Mapk Signaling ◽  
Ros Generation ◽  
Dependent Manner ◽  
Jnk Signaling ◽  
Apoptosis Markers ◽  
Testicular Size ◽  
Spermatogonia Cell ◽  
Induced Apoptosis ◽  
Dose Dependent

Nonylphenol (NP) is an endocrine-disruptor chemical that negatively affects reproductive health. Testes exposure to NP results in testicular structure disruption and a reduction in testicular size and testosterone levels. However, the effects of NP on spermatogonia in testes have not been fully elucidated. In this study, the molecular mechanisms of NP in GC-1 spermatogonia (spg) cells were investigated. We found that cell viability significantly decreased and apoptosis increased in a dose-dependent manner when GC-1 spg cells were exposed to NP. Furthermore, the expression levels of the pro-apoptotic proteins increased, whereas anti-apoptosis markers decreased in NP-exposed GC-1 spg cells. We also found that NP increased reactive oxygen species (ROS) generation, suggesting that ROS-induced activation of the MAPK signaling pathway is the molecular mechanism of NP-induced apoptosis in GC-1 spg cells. Thus, NP could induce c-Jun phosphorylation; dose-dependent expression of JNK, MKK4, p53, and p38; and the subsequent inhibition of ERK1/2 and MEK1/2 phosphorylation. The genes involved in apoptosis and JNK signaling were also upregulated in GC-1 spg cells treated with NP compared to those in the controls. Our findings suggest that NP induces apoptosis through ROS/JNK signaling in GC-1 spg cells.

scholarly journals Growth-factor-dependent phosphorylation of Bim in mitosis

2005 ◽  
Vol 388 (1) ◽  
pp. 185-194 ◽  
Author(s):  
Mário GRÃOS ◽  
Alexandra D. ALMEIDA ◽  
Sukalyan CHATTERJEE
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Growth Factor ◽  
Cell Fate ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Post Translational Modification ◽  
Proliferating Cells ◽  
Growth Factor Signalling ◽  
Induced Apoptosis

The regulation of survival and cell death is a key determinant of cell fate. Recent evidence shows that survival and death machineries are regulated along the cell cycle. In the present paper, we show that BimEL [a BH3 (Bcl-2 homology 3)-only member of the Bcl-2 family of proteins; Bim is Bcl-2-interacting mediator of cell death; EL is the extra-long form] is phosphorylated in mitosis. This post-translational modification is dependent on MEK (mitogen-activated protein kinase/extracellular-signal-regulated kinase kinase) and growth factor signalling. Interestingly, FGF (fibroblast growth factor) signalling seems to play an essential role in this process, since, in the presence of serum, inhibition of FGF receptors abrogated phosphorylation of Bim in mitosis. Moreover, we have shown bFGF (basic FGF) to be sufficient to induce phosphorylation of Bim in serum-free conditions in any phase of the cell cycle, and also to significantly rescue cells from serum-deprivation-induced apoptosis. Our results show that, in mitosis, Bim is phosphorylated downstream of growth factor signalling in a MEK-dependent manner, with FGF signalling playing an important role. We suggest that phosphorylation of Bim is a decisive step for the survival of proliferating cells.

Induction of apoptosis by particulate matter: role of TNF-α and MAPK

1998 ◽  
Vol 275 (5) ◽  
pp. L942-L949 ◽  
Author(s):  
Beek Yoke Chin ◽  
Mary E. Choi ◽  
Marie D. Burdick ◽  
Robert M. Strieter ◽  
Terence H. Risby ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Carbon Black ◽  
Mapk Pathway ◽  
Time Dependent ◽  
Raw 264.7 Cells ◽  
Raw 264.7 ◽  
Dependent Manner ◽  
Mapk Kinase ◽  
Tnf Α ◽  
Induced Apoptosis

Particulate matter (PM) is a major by-product from the combustion of fossil fuels. The biological target of inhaled PM is the pulmonary epithelium and resident macrophages. In this study, we demonstrate that cultured macrophages (RAW 264.7 cells) exposed continously to a well-defined model of PM [benzo[ a]pyrene adsorbed on carbon black (CB+BaP)] exhibit a time-dependent expression and release of the cytokine tumor necrosis factor-α (TNF-α). CB+BaP also evoked programmed cell death or apoptosis in cultured macrophages as assessed by genomic DNA-laddering assays. The CB+BaP-induced apoptosis was inhibited when macrophages were treated with CB+BaP in the presence of a neutralizing antibody to TNF-α, suggesting that TNF-α plays an important role in mediating CB+BaP-induced apoptosis in macrophages. Interestingly, neither untreated carbon black nor benzo[ a]pyrene alone induced apoptosis or caused the release of TNF-α in RAW 264.7 cells. Moreover, we observed that TNF-α activates mitogen-activated protein kinase (MAPK) activity, the extracellular signal-regulated kinases p42/p44, in a time-dependent manner. RAW 264.7 cells treated with PD-098059, a selective inhibitor of MAPK kinase activity, did not exhibit CB+BaP-induced apoptosis and TNF-α secretion. Furthermore, cells treated with the MAPK kinase inhibitor did not undergo TNF-α-induced apoptosis. Taken together, our data suggest that TNF-α mediates PM-induced apoptosis and that the MAPK pathway may play an important role in regulating this pathway.

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