Inhibition of NF-κB essentially contributes to arsenic-induced apoptosis

Blood ◽  
2003 ◽  
Vol 102 (3) ◽  
pp. 1028-1034 ◽  
Author(s):  
Stephan Mathas ◽  
Andreas Lietz ◽  
Martin Janz ◽  
Michael Hinz ◽  
Franziska Jundt ◽  
...  
Keyword(s):  
Cell Lines ◽  
Target Genes ◽  
Nuclear Factor Κb ◽  
Model Systems ◽  
Direct Role ◽  
Iκb Kinase ◽  
Transient Overexpression ◽  
Induced Apoptosis ◽  
Necrosis Factor

Abstract Arsenic can induce apoptosis and is an efficient drug for the treatment of acute promyelocytic leukemia. Currently, clinical studies are investigating arsenic as a therapeutic agent for a variety of malignancies. In this study, Hodgkin/Reed-Sternberg (HRS) cell lines served as model systems to characterize the role of nuclear factor–κB (NF-κB) in arsenic-induced apoptosis. Arsenic rapidly down-regulated constitutive IκB kinase (IKK) as well as NF-κB activity and induced apoptosis in HRS cell lines containing functional IκB proteins. In these cell lines, apoptosis was blocked by inhibition of caspase-8 and caspase-3–like activity. Furthermore, arsenic treatment down-regulated NF-κB target genes, including tumor necrosis factor-αreceptor–associated factor 1 (TRAF1), c-IAP2, interleukin-13 (IL-13), and CCR7. In contrast, cell lines with mutated, functionally inactive IκB proteins or with a weak constitutive IKK/NF-κB activity showed no alteration of the NF-κB activity and were resistant to arsenic-induced apoptosis. A direct role of the NF-κB pathway in arsenic-induced apoptosis is shown by transient overexpression of NF-κB–p65 in L540Cy HRS cells, which protected the cells from arsenic-induced apoptosis. In addition, treatment of NOD/SCID mice with arsenic trioxide induced a dramatic reduction of xenotransplanted L540Cy Hodgkin tumors concomitant with NF-κB inhibition. We conclude that inhibition of NF-κB contributes to arsenic-induced apoptosis. Furthermore, pharmacologic inhibition of the IKK/NF-κB activity might be a powerful treatment option for Hodgkin lymphoma.

Regulation of Chemoresistance and Immune Resistance of B-NHL Cell Lines by Overexpression of YY1 and Bcl-xL, Respectively: Reversal of Resistance by Rituximab.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1517-1517
Author(s):  
Mario I. Vega ◽  
Ali R. Jazirehi ◽  
Sara Huerta-Yepez ◽  
Benjamin Bonavida
Keyword(s):  
Tumor Cells ◽  
Cell Lines ◽  
Drug Induced ◽  
Direct Role ◽  
No Donor ◽  
Immune Resistance ◽  
Apoptosis Inhibition ◽  
Immune Mediated ◽  
Induced Apoptosis

Abstract We have recently reported that treatment of B-NHL cell lines with rituximab sensitizes the tumor cells to both chemotherapy and Fas-induced apoptosis (Jazirehi and Bonavida, 2005, Oncogene, 24:2121–2145). This study investigated the underlying molecular mechanism of rituximab-mediated reversal of resistance. Treatment of B-NHL cell lines inhibited the constitutively activated NF- κB. Cells expressing dominant active IκB or treated with NF-κB specific inhibitors were sensitized to both drugs and FasL agonist mAb (CH-11)-induced apoptosis. Downregulation of Bcl-xL expression via inhibition of NF-κB activity correlated with chemosensitivity. The direct role of Bcl-xL in chemoresistance was demonstrated by the use of Bcl-xL overexpressing Ramos cells, Ramos HA-BclxL (gift from Genhong Cheng, UCLA), which were not sensitized by rituximab to drug-induced apoptosis. However, inhibition of Bcl-xL in Ramos HA-Bcl-x resulted in sensitization to drug-induced apoptosis. The role of Bcl-xL expression in the regulation of Fas resistance was not apparent as Ramos HA-Bcl cells were as sensitive as the wild type cells to CH-11-induced apoptosis. Several lines of evidence support the direct role of the transcription repressor Yin-Yang 1 (YY1) in the regulation of resistance to CH-11-induced apoptosis. Inhibition of YY1 activity by either rituximab, the NO donor DETANONOate, or following transfection with YY1 siRNA all resulted in upregulation of Fas expression and sensitization to CH-11-induced apoptosis. These findings suggest two complementary mechanisms underlying the chemo-sensitization and immuno-sensitization of B NHL cells by rituximab via inhibition of NF-κB. The regulation of chemoresistance by NF-κB is mediated via Bcl-xL expression whereas the regulation of Fas resistance by NF-κB is mediated via YY1 expression and activity. These findings suggest that drug-resistant NHL tumor cells may be sensitive to immune-mediated therapeutics.

scholarly journals NF-κB Inducers Upregulate cFLIP, a Cycloheximide-Sensitive Inhibitor of Death Receptor Signaling

2001 ◽  
Vol 21 (12) ◽  
pp. 3964-3973 ◽  
Author(s):  
Sebastian Kreuz ◽  
Daniela Siegmund ◽  
Peter Scheurich ◽  
Harald Wajant
Keyword(s):  
Cell Lines ◽  
Death Receptor ◽  
Jurkat Cells ◽  
Negative Regulator ◽  
Inhibitory Protein ◽  
Iκb Kinase ◽  
Low Concentrations ◽  
Death Receptor Signaling ◽  
Induced Apoptosis ◽  
Necrosis Factor

ABSTRACT The caspase 8 homologue FLICE-inhibitory protein (cFLIP) is a potent negative regulator of death receptor-induced apoptosis. We found that cFLIP can be upregulated in some cell lines under critical involvement of the NF-κB pathway, but NF-κB activation was clearly not sufficient for cFLIP induction in all cell lines. Treatment of SV80 cells with the proteasome inhibitor N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal (MG-132) or geldanamycin, a drug interfering with tumor necrosis factor (TNF)-induced NF-κB activation, inhibited TNF-induced upregulation of cFLIP. Overexpression of a nondegradable IκBα mutant (IκBα-SR) or lack of IκB kinase γ expression completely prevented phorbol myristate acetate-induced upregulation of cFLIP mRNA in Jurkat cells. These data point to an important role for NF-κB in the regulation of the cFLIP gene. SV80 cells normally show resistance to TNF-related apoptosis-inducing ligand (TRAIL) and TNF, as apoptosis can be induced only in the presence of low concentrations of cycloheximide (CHX). However, overexpression of IκBα-SR rendered SV80 cells sensitive to TRAIL-induced apoptosis in the absence of CHX, and cFLIP expression was able to reverse the proapoptotic effect of NF-κB inhibition. Western blot analysis further revealed that cFLIP, but not TRAF1, A20, and cIAP2, expression levels rapidly decrease upon CHX treatment. In conclusion, these data suggest a key role for cFLIP in the antiapoptotic response of NF-κB activation.

scholarly journals IKKα plays a major role in canonical NF-kB signalling in colorectal cells

2022 ◽  
Author(s):  
Jack A Prescott ◽  
Kathryn Balmanno ◽  
Jennifer P Mitchell ◽  
Hanneke Okkenhaug ◽  
Simon J Cook
Keyword(s):  
Cell Lines ◽  
Nuclear Translocation ◽  
Transcriptional Response ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Knock Out ◽  
Iκb Kinase ◽  
Sw620 Cells ◽  
Hct116 Cells

Inhibitor of kappa B (IκB) kinase β (IKKβ) has long been viewed as the dominant IKK in the canonical nuclear factor-κB (NF-κB) signalling pathway, with IKKα being more important in non-canonical NF-κB activation. Here we have investigated the role of IKKα and IKKβ in canonical NF-κB activation in colorectal cells using CRISPR-Cas9 knock-out cell lines, siRNA and selective IKKβ inhibitors. IKKα and IKKβ were redundant for IκBα phosphorylation and turnover since loss of IKKα or IKKβ alone had little (SW620 cells) or no (HCT116 cells) effect. However, in HCT116 cells IKKα was the dominant IKK required for basal phosphorylation of p65 at S536, stimulated phosphorylation of p65 at S468, nuclear translocation of p65 and the NF-κB-dependent transcriptional response to both TNFα and IL-1α. In these cells IKKβ was far less efficient at compensating for the loss of IKKα than IKKα was able to compensate for the loss of IKKβ. This was confirmed when siRNA was used to knock-down the non-targeted kinase in single KO cells. Critically, the selective IKKβ inhibitor BIX02514 confirmed these observations in WT cells and similar results were seen in SW620 cells. Notably, whilst IKKα loss strongly inhibited TNFα-dependent p65 nuclear translocation, IKKα and IKKβ contributed equally to c-Rel nuclear translocation indicating that different NF-κB subunits exhibit different dependencies on these IKKs. These results demonstrate a major role for IKKα in canonical NF-κB signalling in colorectal cells and may be relevant to efforts to design IKK inhibitors, which have focused largely on IKKβ to date.

scholarly journals NF-κB and AP-1 Connection: Mechanism of NF-κB-Dependent Regulation of AP-1 Activity

2004 ◽  
Vol 24 (17) ◽  
pp. 7806-7819 ◽  
Author(s):  
Shuichi Fujioka ◽  
Jiangong Niu ◽  
Christian Schmidt ◽  
Guido M. Sclabas ◽  
Bailu Peng ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Target Genes ◽  
Nuclear Factor Κb ◽  
Activator Protein 1 ◽  
Murine Embryonic Fibroblast ◽  
Downstream Target ◽  
Iκb Kinase ◽  
Extracellular Signal ◽  
Downstream Target Gene

ABSTRACT Nuclear factor κB (NF-κB) and activator protein 1 (AP-1) transcription factors regulate many important biological and pathological processes. Activation of NF-κB is regulated by the inducible phosphorylation of NF-κB inhibitor IκB by IκB kinase. In contrast, Fos, a key component of AP-1, is primarily transcriptionally regulated by serum responsive factors (SRFs) and ternary complex factors (TCFs). Despite these different regulatory mechanisms, there is an intriguing possibility that NF-κB and AP-1 may modulate each other, thus expanding the scope of these two rapidly inducible transcription factors. To determine whether NF-κB activity is involved in the regulation of fos expression in response to various stimuli, we analyzed activity of AP-1 and expression of fos, fosB, fra-1, fra-2, jun, junB, and junD, as well as AP-1 downstream target gene VEGF, using MDAPanc-28 and MDAPanc-28/IκBαM pancreatic tumor cells and wild-type, IKK1−/−, and IKK2−/− murine embryonic fibroblast cells. Our results show that elk-1, a member of TCFs, is one of the NF-κB downstream target genes. Inhibition of NF-κB activity greatly decreased expression of elk-1. Consequently, the reduced level of activated Elk-1 protein by extracellular signal-regulated kinase impeded constitutive, serum-, and superoxide-inducible c-fos expression. Thus, our study revealed a distinct and essential role of NF-κB in participating in the regulation of elk-1, c-fos, and VEGF expression.

Mechanism of staurosporine-induced apoptosis in murine hepatocytes

2002 ◽  
Vol 282 (5) ◽  
pp. G825-G834 ◽  
Author(s):  
Guoping Feng ◽  
Neil Kaplowitz
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Caspase 3 ◽  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Jurkat Cells ◽  
Primary Hepatocytes ◽  
Iκb Kinase ◽  
Apoptosis Protein ◽  
Induced Apoptosis

Staurosporine (STS) induces apoptosis in various cell lines. We report in this study that primary cultured mouse hepatocytes are less sensitive to STS compared with Jurkat cells and Huh-7 cells. In contrast to the cell lines, no apparent release of cytochrome c or loss of mitochondrial transmembrane potential was detected in primary hepatocytes undergoing STS-induced apoptosis. Caspase-3 was activated in primary hepatocytes by STS treatment, but caspase-9 and -12 were not activated, and caspase-3 activation is not dependent on caspase-8. These findings point to a novel pathway for caspase-3 activation by STS in primary hepatocytes. Pretreatment with caspase inhibitor converted STS-induced apoptosis of hepatocytes to necrotic cell death without significantly changing total cell death. Thus STS causes hepatocytes to commit to death upstream of the activation of caspases. We also demonstrated that STS dramatically sensitized primary hepatocytes to tumor necrosis factor-α-induced apoptosis. STS activated IκB kinase and nuclear factor-κB (NF-κB) nuclear translocation and DNA binding but inhibited transactivation of IκB-α, inducible nitric oxide synthase, and inhibitor of apoptosis protein-1 in hepatocytes and NF-κB reporter in transfected Huh-7 cells.

The Role of Nuclear Factor-kappaB and Melanogenesis in Tumor Necrosis Factor-Alpha-Induced Apoptosis of Normal Human Melanocytes

2002 ◽  
Vol 15 (5) ◽  
pp. 321-329 ◽  
Author(s):  
Jing Shang ◽  
Jürgen Eberle ◽  
Christoph C. Geilen ◽  
Amir M. Hossini ◽  
Lothar F. Fecker ◽  
...  
Keyword(s):  
Tumor Necrosis ◽  
Nuclear Factor Kappab ◽  
Nuclear Factor ◽  
Necrosis Factor Alpha ◽  
Human Melanocytes ◽  
Normal Human ◽  
Factor Alpha ◽  
Induced Apoptosis ◽  
Necrosis Factor

P04.20 The role of YAP in Glioblastoma cell lines

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii22-ii23
Author(s):  
G Casati ◽  
L Giunti ◽  
A Iorio ◽  
A Marturano ◽  
I Sardi
Keyword(s):  
Cell Viability ◽  
Cell Lines ◽  
Western Blotting ◽  
Cytotoxic Effect ◽  
Target Genes ◽  
Hippo Pathway ◽  
Combined Treatment ◽  
Set Up ◽  
The Hippo Pathway

Abstract BACKGROUND Glioblastoma (GBM) is a primary human malignant brain tumor, the most common in adults. Several studies have highlighted the Hippo-pathway as a cancer signalling network. The Hippo pathway is an evolutionarily conserved signal cascade, which is involved in the control of organ growth. Dysregulations among this pathway have been found in lung, ovarian, liver and colorectal cancer. The key downstream effector of the Hippo-pathway is the Yes-associated protein (YAP); in the nucleus, its function as transcription co-activator is to interact with transcription factors, resulting in the expression of target genes involved in pro-proliferating and anti-apoptotic programs. MATERIAL AND METHODS Using western blotting analysis, we determined the nuclear expression of YAP on three GBM cell lines (U87MG, T98G and A172). To investigate which inhibitors against the Hippo-pathway were the most efficient, we performed a cytotoxic assay: we treated all the three cell lines with different inhibitors such as Verteporfin (VP), Cytochalasin D (CIT), Latrunculin A (LAT), Dobutamine (DOB) and Y27632. Afterwards, we performed a treatment using Doxorubicin (DOX) combined with the inhibitors, evaluating its cytotoxic effect on our cell lines, through cell viability experiments. More western blotting experiments were performed to investigate the oncogenic role of YAP at nucleus level. Furthermore, preliminary experiments have been conducted in order to investigate the apoptosis, senescence and autophagy modulation due to the Hippo-pathway. RESULTS We showed our cell lines express nuclear YAP. We assessed the efficiency of the main inhibitors against Hippo-pathway, proving that VP, LAT A and CIT show a strong cytostatic effect, linked to time increase; plus we saw a cytotoxic effect on T98G. The association of DOX with selected inhibitors is able to reduce cell viability and nuclear YAP expression rate in all three GBM lines. Finally, preliminary experiments were set up to assess how and if the mechanisms of apoptosis, autophagy and senescence were affected by the Hippo-pathway. The combination of DOX with inhibitors promotes resistance to apoptosis. CONCLUSION Our results show that nuclear YAP is present in all tumor lines, thus confirming that this molecular pathway is functioning in GBM lines. Nuclear YAP is more highly expressed after DOX administration. Moreover, the combined treatment (DOX with Hippo-pathway inhibitors) reduces both cell proliferation and viability, and increases the rate of apoptosis. Preliminary experiments on senescence and autophagy were used to determine the best Hippo-pathway inhibitor. These data demonstrate that the Hippo-pathway plays a crucial role in GBM proliferation and resistance to apoptosis. Inhibiting this pathway and in particular the transcription factor YAP, in association with DOX, might be an excellent therapeutic target.

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