scholarly journals Ribavirin and Alpha Interferon Enhance Death Receptor-Mediated Apoptosis and Caspase Activation in Human Hepatoma Cells

2003 ◽  
Vol 47 (6) ◽  
pp. 1912-1921 ◽  
Author(s):  
Stephan F. Schlosser ◽  
Markus Schuler ◽  
Christoph P. Berg ◽  
Kirsten Lauber ◽  
Klaus Schulze-Osthoff ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Death Receptor ◽  
Alpha Interferon ◽  
Target Cells ◽  
Clinical Effects ◽  
Caspase Activation ◽  
Human Hepatoma Cells ◽  
Promoting Effect

ABSTRACT The molecular mechanisms underlying the clinical effects of alpha interferon (IFN) and ribavirin are not understood. Elimination of infected cells occurs in part by cytotoxic T lymphocytes (CTLs) expressing CD95 ligand and thereby attacking target cells which are positive for the death receptor CD95. Since many viruses have evolved mechanisms to inhibit apoptosis, the opposite, namely, promotion of apoptosis, could be a strategy to strengthen the host antiviral response. In the present study, we have asked whether the antiviral substances IFN and ribavirin could support CD95-mediated apoptosis by interfering with the activation of caspases, a family of proteases known for their essential role in apoptosis. HepG2 cells, stimulated with the agonistic anti-CD95 antibody, served as a minimal model to mimic the CD95 stimulation ocurring during a CTL attack of target cells in vivo. Apoptosis was quantitated by flow cytometric detection of hypodiploid nuclei. Caspase activity was measured by cytofluorometry, immunocytochemistry, and immunoblot analysis. IFN and ribavirin sensitized HepG2 cells for CD95-mediated apoptosis. This effect was correlated with an increase in CD95-mediated caspase activation and enhanced cleavage of the caspase substrate poly(ADP-ribose) polymerase. Furthermore, the positive effect on CD95-mediated caspase activation by IFN and ribavirin was confirmed by immunocytochemistry for activated caspase-3 and by immunoblot detection of activated caspase-3, caspase-7, and caspase-8. Our data demonstrate that the antiviral substances IFN and ribavirin are able to sensitize for CD95-mediated apoptosis. IFN and ribavirin also enhance CD95-mediated caspase activation, which might in part be responsible for the apoptosis-promoting effect of these antiviral compounds.

Comparative cytotoxicity and apoptotic pathways induced by nanosilver in human liver HepG2 and L02 cells

2018 ◽  
Vol 37 (12) ◽  
pp. 1293-1309 ◽  
Author(s):  
Y Xue ◽  
J Wang ◽  
Y Huang ◽  
X Gao ◽  
L Kong ◽  
...  
Keyword(s):  
Cell Line ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Hepatoma Cell ◽  
Death Receptor ◽  
Hepatoma Cell Line ◽  
Dependent Manner ◽  
Death Receptor Pathway ◽  
L02 Cells

Silver nanoparticles are used in many commercial products in daily life. Exposure to nanosilver has hepatotoxic effects in animals. This study investigated the cytotoxicity associated with polyvinylpyrrolidone-coated nanosilver (23.44 ± 4.92 nm in diameter) exposure in the human hepatoma cell line (HepG2) and normal hepatic cell line (L02), and the molecular mechanisms induced by nanosilver in HepG2 cells. Nanosilver, in doses of 20–160 μg mL−1 for 24 and 48 h, reduced cell viability in a dose- and time-dependent manner and induced cell membrane leakage and mitochondria injury in both cell lines; these effects were more pronounced in HepG2 cells than in L02 cells. Intracellular oxidative stress was documented by reactive oxygen species (ROS) being generated in HepG2 cells but not in L02 cells, an effect possibly due to differential uptake of nanosilver by cancer cells and normal cells. In HepG2 cells, apoptosis was documented by finding that ROS triggered a decrease in mitochondrial membrane potential, an increase in cytochrome c release, activation of caspase 3 and caspase 9, and a decrease in the ratio of Bcl-2/Bax. Furthermore, nanosilver activated the Fas death receptor pathway by downregulation of nuclear factor-κB and activation of caspase 8 and caspase 3. These results suggest that apoptosis induced by nanosilver in HepG2 cells is mediated via a mitochondria-dependent pathway and the Fas death receptor pathway. These findings provide toxicological and mechanistic information that can help in assessing the effects of nanosilver in biological systems, including the potential for anticancer activities.

scholarly journals The Phosphatidylserine Receptor TIM-1 Enhances Authentic Chikungunya Virus Cell Entry

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1828
Author(s):  
Jared Kirui ◽  
Yara Abidine ◽  
Annasara Lenman ◽  
Koushikul Islam ◽  
Yong-Dae Gwon ◽  
...  
Keyword(s):  
Chikungunya Virus ◽  
Molecular Mechanisms ◽  
Rna Virus ◽  
Ectopic Expression ◽  
Point Mutations ◽  
Cell Entry ◽  
Target Cells ◽  
Human Hepatoma Cells ◽  
Chikv Infection ◽  
Phosphatidylserine Receptor

Chikungunya virus (CHIKV) is a re-emerging, mosquito-transmitted, enveloped positive stranded RNA virus. Chikungunya fever is characterized by acute and chronic debilitating arthritis. Although multiple host factors have been shown to enhance CHIKV infection, the molecular mechanisms of cell entry and entry factors remain poorly understood. The phosphatidylserine-dependent receptors, T-cell immunoglobulin and mucin domain 1 (TIM-1) and Axl receptor tyrosine kinase (Axl), are transmembrane proteins that can serve as entry factors for enveloped viruses. Previous studies used pseudoviruses to delineate the role of TIM-1 and Axl in CHIKV entry. Conversely, here, we use the authentic CHIKV and cells ectopically expressing TIM-1 or Axl and demonstrate a role for TIM-1 in CHIKV infection. To further characterize TIM-1-dependent CHIKV infection, we generated cells expressing domain mutants of TIM-1. We show that point mutations in the phosphatidylserine binding site of TIM-1 lead to reduced binding, entry, and infection of CHIKV. Ectopic expression of TIM-1 renders immortalized keratinocytes permissive to CHIKV, whereas silencing of endogenously expressed TIM-1 in human hepatoma cells reduces CHIKV infection. Altogether, our findings indicate that, unlike Axl, TIM-1 readily promotes the productive entry of authentic CHIKV into target cells.

The extrinsic caspase pathway modulates endotoxin-induced diaphragm contractile dysfunction

2007 ◽  
Vol 102 (4) ◽  
pp. 1649-1657 ◽  
Author(s):  
Gerald S. Supinski ◽  
Xinying Ji ◽  
Wenyi Wang ◽  
Leigh A. Callahan
Keyword(s):  
Caspase 3 ◽  
Death Receptor ◽  
Interferon Γ ◽  
Caspase 8 ◽  
Contractile Dysfunction ◽  
Tnf Receptor ◽  
Caspase Activation ◽  
Caspase 9 ◽  
Diaphragm Dysfunction ◽  
Tnf Α

The mechanisms by which infections induce diaphragm dysfunction remain poorly understood. The purpose of this study was to determine which caspase pathways (i.e., the extrinsic, death receptor-linked caspase-8 pathway, and/or the intrinsic, mitochondrial-related caspase-9 pathway) are responsible for endotoxin-induced diaphragm contractile dysfunction. We determined 1) whether endotoxin administration (12 mg/kg IP) to mice induces caspase-8 or -9 activation in the diaphragm; 2) whether administration of a caspase-8 inhibitor ( N-acetyl-Ile-Glu-Thr-Asp-CHO, 3 mg/kg iv) or a caspase-9 inhibitor ( N-acetyl-Leu-Glu-His-Asp-CHO, 3 mg/kg iv) blocks endotoxin-induced diaphragmatic weakness and caspase-3 activation; 3) whether TNF receptor 1-deficient mice have reduced caspase activation and diaphragm dysfunction following endotoxin; and 4) whether cytokines (TNF-α or cytomix, a mixture of TNF-α, interleukin-1β, interferon-γ, and endotoxin) evoke caspase activation in C2C12 myotubes. Endotoxin markedly reduced diaphragm force generation ( P < 0.001) and induced increases in caspase-3 and caspase-8 activity ( P < 0.03), but failed to increase caspase-9. Inhibitors of caspase-8, but not of caspase-9, prevented endotoxin-induced reductions in diaphragm force and caspase-3 activation ( P < 0.01). Mice deficient in TNF receptor 1 also had reduced caspase-8 activation ( P < 0.001) and less contractile dysfunction ( P < 0.01) after endotoxin. Furthermore, incubation of C2C12 cells with either TNF-α or cytomix elicited significant caspase-8 activation. The caspase-8 pathway is strongly activated in the diaphragm following endotoxin and is responsible for caspase-3 activation and diaphragm weakness.

scholarly journals Glucocorticoids Affect Male Testicular Steroidogenesis

2020 ◽  
pp. S205-S210
Author(s):  
R. HAMPL ◽  
L. STÁRKA
Keyword(s):  
Leydig Cells ◽  
Glucocorticoid Receptors ◽  
Molecular Mechanisms ◽  
Target Cells ◽  
Clinical Effects ◽  
Steroid Production ◽  
Glucocorticoid Treatment ◽  
Testicular Steroidogenesis ◽  
And Function

Through their receptors at each level of hypothalamo-pituitary-gonadal axis glucocorticoid excess, either endogenous or administered or stress-induced, could affect steroid production in the testis and thus male fertility. The main ways by which glucocorticoids act are as follows: 1) Affecting gonadoliberin and LH synthesis and release through glucocorticoid receptors in hypothalamic neurons and pituitary gonadotropes. 2) By so far not clearly evidenced reduction of the number of LH receptors on the membrane of Leydig cells. 3) By affecting expression and function of steroidogenic enzymes in the testis. 4) By regulation of in situ access of glucocorticoid to its target cells in the testis. 5) By promotion Leydig cell apoptosis. The review provides a survey of physiological and molecular mechanisms staying behind these effects. It does not deal with the clinical effects of glucocorticoid treatment which would substantially exceed the scope of the pater.

scholarly journals Detection of Apoptosis Initiated in Treated HepG2 Cells with t-BHP: The Role of Phytochemicals to Reduce Toxicity and Stop Apoptosis

2021 ◽  
Vol 2 (9) ◽  
pp. 745-767
Author(s):  
Maha J Hashim
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Hepg2 Cells ◽  
Caspase 3 ◽  
Physiological Mechanism ◽  
Oxygen Species ◽  
Caspase Activation ◽  
Apoptosis Detection ◽  
Infected Cells

Apoptosis or programmed cell death is a standard physiological mechanism. It is essential to control the number of cells, balance cell division and cell death, regulate the immune system, and eliminate pathogen-infected cells. Apoptosis entailed a different investigation to determine related biochemical reactions such as activated caspase, Reactive Oxygen Species (ROS), Lipid Peroxidation (LPO), and Evaluation of Glutathione Content (GSH) by using different techniques. HepG2 cells were exposed to +/- 0.4 and 0.8 mM t-BHP for specific times to induce toxicity for apoptosis detection. We aim to investigate the mechanism of cell death in treated HepG2 with t-BHP under consideration of the conditions of the cytoprotection assay. Results showed no strong evidence for apoptosis, although caspase-3 activity increased significantly (p ≤ 0.05) in treated HpG2 cells with 0.8 mM t-BHP at 150 minutes. The weak proof for apoptosis may attribute to the participation of Calpain through the cross-talk in blocking the caspase- activation. Similarly, we obtained significant ROS and lipid peroxidation increases in treated HepG2 cells with 0.8 mM t-BHP (p ≤ 0.05 and 0.01 respectively) at 150 minutes. Moreover, reported a (non-significant) decline in GSH amounts. Treatment of the cells with Q and I3C under the conditions used in the cytoprotection study prevented the weak activation of caspase-3 identified by western blot.

A novel TNFR1-triggered apoptosis pathway mediated by class IA PI3Ks in neutrophils

Blood ◽  
2011 ◽  
Vol 117 (22) ◽  
pp. 5953-5962 ◽  
Author(s):  
Barbara Geering ◽  
Ursina Gurzeler ◽  
Elena Federzoni ◽  
Thomas Kaufmann ◽  
Hans-Uwe Simon
Keyword(s):  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Caspase 8 ◽  
Tnf Receptor ◽  
Caspase Activation ◽  
Apoptosis Pathway ◽  
Tnf Α ◽  
Pi3k Activation ◽  
Amplification Loop ◽  
Induced Apoptosis

Abstract The most common form of neutrophil death is apoptosis. In the present study, we report surprising differences in the molecular mechanisms used for caspase activation between FAS/CD95-stimulated and TNF receptor 1 (TNFR1)–stimulated neutrophils. Whereas FAS-induced apoptosis was followed by caspase-8 activation and required Bid to initiate the mitochondrial amplification loop, TNF-α–induced apoptosis involved class IA PI3Ks, which were activated by MAPK p38. TNF-α–induced PI3K activation resulted in the generation of reactive oxygen species, which activated caspase-3, a mechanism that did not operate in neutrophils without active NADPH oxidase. We conclude that in neutrophils, proapoptotic pathways after TNFR1 stimulation are initiated by p38 and PI3K, but not by caspase-8, a finding that should be considered in anti-inflammatory drug-development strategies.

scholarly journals Live cell evaluation of granzyme delivery and death receptor signaling in tumor cells targeted by human natural killer cells

Blood ◽  
2015 ◽  
Vol 126 (8) ◽  
pp. e1-e10 ◽  
Author(s):  
Alexandra C. Vrazo ◽  
Adrianne E. Hontz ◽  
Sarah K. Figueira ◽  
Braeden L. Butler ◽  
Julie M. Ferrell ◽  
...  
Keyword(s):  
Natural Killer Cells ◽  
Natural Killer ◽  
Killer Cell ◽  
Death Receptor ◽  
Target Cells ◽  
Caspase Activation ◽  
Killer Cells ◽  
Human Natural Killer Cells ◽  
Death Receptor Signaling ◽  
Receptor Ligation

Key Points Natural killer cell granzyme B, A, and K delivery and subsequent caspase activation is rapid after conjugation with tumor target cells. Natural killer cells also induce caspase activation through death receptor ligation that can be monitored in real time.

scholarly journals Dexmedetomidine Ameliorates Acute Stress-Induced Kidney Injury by Attenuating Oxidative Stress and Apoptosis through Inhibition of the ROS/JNK Signaling Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yongping Chen ◽  
Xiujing Feng ◽  
Xueyuan Hu ◽  
Jichen Sha ◽  
Bei Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Acute Stress ◽  
Death Receptor ◽  
Kidney Injury ◽  
Jnk Pathway ◽  
Jnk Signaling ◽  
Jnk Signaling Pathway

Acute stress induces tissue damage through excessive oxidative stress. Dexmedetomidine (DEX) reportedly has an antioxidant effect. However, protective roles and related potential molecular mechanisms of DEX against kidney injury induced by acute stress are unknown. Herein, rats were forced to swim 15 min followed by restraint stress for 3 h with/without DEX (30 μg/kg). Successful model establishment was validated by an open-field test. Assessment of renal function (creatinine, urea nitrogen), histopathology, oxidative stress (malondialdehyde, glutathione, and superoxide dismutase), and apoptosis (transferase-mediated dUTP nick end labeling) was performed. Localization of apoptosis was determined by immunohistochemistry of cleaved caspase 3 protein. In addition, key proteins of the death receptor-mediated pathway, mitochondrial pathway, endoplasmic reticulum stress (ERS) pathway, and ROS/JNK signaling pathway were measured by Western blot. We found that DEX significantly improved renal dysfunction, ameliorated kidney injury, reduced oxidative stress, and alleviated apoptosis. DEX also inhibited the release of norepinephrine (NE), decreased the production of reactive oxygen species (ROS), and inhibited JNK phosphorylation. Additionally, DEX downregulated the expression of Bax, cytochrome C, cleaved caspase 9, and cleaved caspase 3 proteins in mitochondria-dependent pathways. In summary, DEX protects against acute stress-induced kidney injury in rats by reducing oxidative stress and apoptosis via inhibition of the ROS/JNK pathway.

Inhibition of Migration and Invasion of Hepatocarcinoma HepG2 Cells by Dietary Saponins via Targeting HIF-1α

2018 ◽  
Vol 18 (7) ◽  
pp. 1025-1031
Author(s):  
Cheng Luo ◽  
Di Wu ◽  
Meiling Chen ◽  
Wenhua Miao ◽  
Changfeng Xue ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Confocal Microscopy ◽  
Protein Expression ◽  
Mtt Assay ◽  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Migration And Invasion ◽  
Rt Pcr ◽  
Gene And Protein Expression ◽  
Simulated Hypoxia

Background: Different saponins from herbs have been used as tonic or functional foods, and for treatment of various diseases including cancers. Although clinical data has supported the function of these saponins, their underlying molecular mechanisms have not been well defined. Methods: With the simulated hypoxia created by 8 hours of Cu++ exposure and following 24 hour incubation with different concentration of saponins in HepG2 cells for MTT assay, migration and invasion assays, and for RT-PCR, and with each group of cells for immunofluorescence observation by confocal microscopy. Results： ZC-4 had the highest rate of inhibition of cell proliferation by MTT assay, and the highest inhibition of migration rate by in vitro scratch assay, while ZC-3 had the highest inhibition of invasion ratio by transwell assay. Under the same simulated hypoxia, the molecular mechanism of saponin function was conducted by measuring the gene expression of Hypoxia Inducible Factor (HIF)-1α through RT-PCR, in which ZC-3 showed a potent inhibition of gene HIF-1α. For the protein expression by immunofluorescence staining with confocal microscopy, HIF-1α was also inhibited by saponins, with the most potent one being ZC-4 after eight hours’ relatively hypoxia incubation. Conclusion: Saponins ZC-4 and ZC-3 have the potential to reduce HepG2 cell proliferation, migration and invasion caused by hypoxia through effectively inhibiting the gene and protein expression of HIF-1α directly and as antioxidant indirectly

The Anti-Proliferative Activity of Anisosciadone: A New Guaiane Sesquiterpene from Anisosciadium lanatum

2019 ◽  
Vol 19 (9) ◽  
pp. 1114-1119 ◽  
Author(s):  
Ahmed A. Mahmoud ◽  
Wael M. El-Sayed
Keyword(s):  
Anticancer Agents ◽  
Antiproliferative Activity ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Chemical Constituents ◽  
Spectroscopic Techniques ◽  
Significant Activity ◽  
Caspase 9 ◽  
P53 Expression ◽  
Expression And Activity

Background: The increase in cancer rate and the development of resistant tumors require a continuous search for new anticancer agents. Aims: This study aimed to analyze and identify the chemical constituents of Anisosciadium lanatum, and to investigate the antiproliferative activity of the identified constituents against various human cell lines (HepG2, MCF7, HT29, A549, and PC3) along with the possible molecular mechanisms involved. Methods: The structure of the isolated compounds was determined by spectroscopic techniques including HRFABMS, GC-MS, IR, and 400 MHz 1D and 2D NMR analyses (1H, 13C NMR, DEPT, 1H-1H COSY, HMQC, HMBC and NOESY). The antiproliferative activity and IC50 value of the isolated compounds were measured and compared to doxorubicin. Results: A new guaiane sesquiterpene containing a rare epoxide structural element, 10β,11β−epoxy−1α,4β,5β,7αΗ- guaiane-9-one, anisosciadone (1), and stigmasterol (2) have been isolated from the plant. Anisosciadone (1) showed a significant antiproliferative activity against liver, colon, and lung cells only, while stigmasterol (2) had a significant activity against liver, colon, and breast cells. Both 1 and 2 caused no cytotoxicity to normal fibroblasts. Anisosciadone elevated the expression and activity of Caspase 3 as well as p53 expression without affecting Caspase 9 in HepG2 cells. It also caused ~ 50% downregulation in cdk1 expression. Conclusion: Taken together, anisosciadone was specific in action against cancer cells and induced apoptosis in liver cells. It also has a unique feature by elevating the expression and activity of Caspase 3 without affecting the initiator Caspase 9. Therefore, anisosciadone deserves more investigation as a targeted therapy for cancer.

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