Testes-specific protease 50 (TSP50) promotes cell proliferation through the activation of the nuclear factor κB (NF-κB) signalling pathway

2011 ◽  
Vol 436 (2) ◽  
pp. 457-467 ◽  
Author(s):  
Zhen-Bo Song ◽  
Yong-Li Bao ◽  
Yu Zhang ◽  
Xu-Guang Mi ◽  
Ping Wu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Colony Formation ◽  
Nuclear Translocation ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Nuclear Factor Κb ◽  
Signalling Pathway ◽  
Nuclear Factor ◽  
Iκb Kinase ◽  
Specific Protease

TSP50 (testes-specific protease 50) is a testis-specific expression protein, which is expressed abnormally at high levels in breast cancer tissues. This makes it an attractive molecular marker and a potential target for diagnosis and therapy; however, the biological function of TSP50 is still unclear. In the present study, we show that overexpression of TSP50 in CHO (Chinese-hamster ovary) cells markedly increased cell proliferation and colony formation. Mechanistic studies have revealed that TSP50 can enhance the level of TNFα (tumour necrosis factor α)- and PMA-induced NF-κB (nuclear factor κB)-responsive reporter activity, IκB (inhibitor of NF-κB) α degradation and p65 nuclear translocation. In addition, the knockdown of endogenous TSP50 in MDA-MB-231 cells greatly inhibited NF-κB activity. Co-immunoprecipitation studies demonstrated an interaction of TSP50 with the NF-κB–IκBα complex, but not with the IKK (IκB kinase) α/β–IKKγ complex, which suggested that TSP50, as a novel type of protease, promoted the degradation of IκBα proteins by binding to the NF-κB–IκBα complex. Our results also revealed that TSP50 can enhance the expression of NF-κB target genes involved in cell proliferation. Furthermore, overexpression of a dominant-negative IκB mutant that is resistant to proteasome-mediated degradation significantly reversed TSP50-induced cell proliferation, colony formation and tumour formation in nude mice. Taken together, the results of the present study suggest that TSP50 promotes cell proliferation, at least partially, through activation of the NF-κB signalling pathway.

scholarly journals Thyroid-Stimulating Hormone Induces Interleukin-6 Release from Human Adipocytes through Activation of the Nuclear Factor-κB Pathway

Endocrinology ◽  
2008 ◽  
Vol 149 (6) ◽  
pp. 3062-3066 ◽  
Author(s):  
Tayze T. Antunes ◽  
AnneMarie Gagnon ◽  
Melanie L. Langille ◽  
Alexander Sorisky
Keyword(s):  
Nuclear Translocation ◽  
Chinese Hamster ◽  
Fold Increase ◽  
Nuclear Factor Κb ◽  
Thyroid Stimulating Hormone ◽  
Nuclear Factor ◽  
Human Adipocytes ◽  
Ovarian Cells ◽  
Iκb Kinase ◽  
Iκbα Degradation

Our objective was to identify the signaling pathway activated by TSH that induces IL-6 secretion from human abdominal sc differentiated adipocytes. Human abdominal sc preadipocytes in culture were differentiated into adipocytes. IL-6 release stimulated by TSH was inhibited by 35% (P < 0.05) with SN50, an inhibitor of nuclear factor-κB (NF-κB) nuclear translocation, and 60% (P < 0.01) with sc-514, an inhibitor of inhibitory-κB (IκB) kinase (IKK)-β. Phosphorylation of IKKβ increased upon TSH treatment (10.3-fold, P < 0.01), and IκBα levels were reduced by 78% (P < 0.01). TSH activated NF-κB (23-fold, P < 0.001), a process that was inhibited (60%, P < 0.01) by SN50. Inhibition of protein kinase A by H89 did not affect TSH-stimulated IKKβ phosphorylation or IκBα degradation. TSH-mediated NF-κB activation and IL-6 induction also specifically occurred in Chinese hamster ovarian cells expressing the human TSH receptor, resulting in a 5.9-fold (P < 0.001) increase in IKKβ phosphorylation and a 9.5-fold increase in IL-6 mRNA expression. Our data demonstrate that the IKKβ/NF-κB pathway is a novel TSH target that is required for TSH-induced IL-6 release from human adipocytes.

scholarly journals Mild Hypothermia Inhibits Nuclear Factor-κB Translocation in Experimental Stroke

2003 ◽  
Vol 23 (5) ◽  
pp. 589-598 ◽  
Author(s):  
Hyung Soo Han ◽  
Murat Karabiyikoglu ◽  
Stephen Kelly ◽  
Raymond A. Sobel ◽  
Midori A. Yenari
Keyword(s):  
Target Genes ◽  
Nuclear Translocation ◽  
Mild Hypothermia ◽  
Brain Temperature ◽  
Nuclear Factor Κb ◽  
Binding Activity ◽  
Cerebral Injury ◽  
Experimental Stroke ◽  
Nuclear Factor ◽  
Iκb Kinase

Nuclear factor-κB (NFκB) is a transcription factor that is activated after cerebral ischemia. NFκB activation leads to the expression of many inflammatory genes involved in the pathogenesis of stroke. The authors previously showed that mild hypothermia is protective even when cooling begins 2 h after stroke onset. In the present study, they examined the influence of hypothermia on NFκB activation. Rats underwent 2 h of transient middle cerebral artery occlusion. Brains were cooled to 33°C immediately after or 2 h after occlusion, and maintained for 2 h. After normothermic ischemia (brain temperature at 38°C), NFκB cytoplasmic expression, nuclear translocation, and binding activity were observed as early as 2 h in the ischemic hemisphere and persisted at 24 h. Hypothermia decreased NFκB translocation and binding activity but did not alter overall expression. Hypothermia also affected the levels of NFκB regulatory proteins by suppressing phosphorylation of NFκB's inhibitory protein (IκB-α) and IκB kinase (IKK-γ) and decreasing IKK activity, but did not alter overall IKK levels. Hypothermia suppressed the expression of two NFκB target genes: inducible nitric oxide synthase and TNF-α. These data suggest that the protective effect of hypothermia on cerebral injury is, in part, related to NFκB inhibition due to decreased activity of IKK.

scholarly journals The viral ankyrin repeat protein (ORF124L) from infectious spleen and kidney necrosis virus attenuates nuclear factor-κB activation and interacts with IκB kinase β

2011 ◽  
Vol 92 (7) ◽  
pp. 1561-1570 ◽  
Author(s):  
Chang-Jun Guo ◽  
Wei-Jian Chen ◽  
Li-Qun Yuan ◽  
Li-Shi Yang ◽  
Shao-Ping Weng ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Luciferase Reporter ◽  
Nuclear Factor ◽  
Mandarin Fish ◽  
Necrosis Virus ◽  
Necrosis Factor Alpha ◽  
Repeat Protein ◽  
Repeat Proteins ◽  
Iκb Kinase

The ankyrin (ANK) repeat is one of the most common protein–protein interaction motifs, found predominantly in eukaryotes and bacteria, but the functions of the ANK repeat are rarely researched in animal viruses, with the exception of poxviruses. Infectious spleen and kidney necrosis virus (ISKNV) is a typical member of the genus Megalocytivirus in the family Iridoviridae and is a causative agent of epizootics in fish. The genome of ISKNV contains four putative viral ANK (vANK) repeat proteins and their functions remain largely unknown. In the present study, it was found that ORF124L, a vANK repeat protein in ISKNV, encodes a protein of 274 aa with three ANK repeats. Transcription of ORF124L was detected at 12 h post-infection (p.i.) and reached a peak at 40 h p.i. ORF124L was found to localize to both the nucleus and the cytoplasm in mandarin fish fry cells. ISKNV ORF124L interacted with the mandarin fish IκB kinase β protein (scIKKβ), and attenuated tumour necrosis factor alpha (TNF-α)- or phorbol myristate acetate (PMA)-induced activity of a nuclear factor κB (NF-κB)–luciferase reporter but did not interfere with the activity of an activator protein 1 (AP-1)–luciferase reporter. Phosphorylation of IκBα and nuclear translocation of NF-κB were also impaired by ISKNV ORF124L. In summary, ORF124L was identified as a vANK repeat protein and its role in inhibition of TNF-α-induced NF-κB signalling was investigated through interaction with the mandarin fish IKKβ. This work may help to improve our understanding of the function of fish iridovirus ANK repeat proteins.

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.

Abstract 501: Nuclear Factor-κB Is Involved in Platelet CD40 Signaling and Activation

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Ahmed Hachem ◽  
Daniel Yacoub ◽  
Younes Zaid ◽  
Walid Mourad ◽  
Yahye Merhi
Keyword(s):  
P38 Mapk ◽  
Platelet Activation ◽  
Nuclear Translocation ◽  
Kinase Inhibitor ◽  
Tumor Necrosis Factor Receptor ◽  
Nuclear Factor Κb ◽  
Mitogen Activated Protein Kinase ◽  
Nuclear Factor ◽  
Iκb Kinase ◽  
Iκbα Phosphorylation

Introduction and hypothesis: CD40 ligand (CD40L) is a thrombo-inflammatory molecule that predicts cardiovascular events. Platelets constitute the major source of soluble CD40L (sCD40L), which has been shown to influence platelet activation. We have previously shown that upon ligation, CD40 potentiates platelet activation and aggregation via p38 mitogen activated protein kinase (MAPK) and Rac1 signaling. In B lymphocytes, CD40 induces activation and nuclear translocation of nuclear factor kappa B (NF-κB), which is dependent on the phosphorylation and dissociation of the inhibitor of kappa B α (IκBα). Given that platelets contain NF-κB, we hypothesized that it may be involved in platelet CD40 signaling. Methods and results: In human platelets, sCD40L induced association of tumor necrosis factor receptor associated factor 2 to CD40, and a time-dependant phosphorylation of IκBα, which is indicative of NF-κB activation. Activation of NF-κB in platelets treated with sCD40L was abolished by CD40L blockade. Pretreatment of platelets with the IκBα inhibitor, BAY 11-7082, reversed IκBα phosphorylation induced by sCD40L, without affecting p38 MAPK activation. On the other hand, pretreatment of platelets with the p38 MAPK phosphorylation inhibitor, SB203580, had no effect on IκBα phosphorylation, indicating a divergence in the signaling pathway originating from CD40 upon its ligation. Finally, inhibition of IκBα phosphorylation by either BAY 11-7082 or the IκB kinase inhibitor VII reversed sCD40L induced platelet activation, as measured by P-selectin expression, and the potentiation of platelet aggregation induced by a priming dose of collagen. Conclusion: This study demonstrates the implication of NF-κB in platelet signaling downstream of CD40, where it plays a role in platelet activation and aggregation upon sCD40L stimulation.

scholarly journals Involvement of diacylglycerol production in activation of nuclear factor κB by a CD14-mediated lipopolysaccharide stimulus

1997 ◽  
Vol 325 (1) ◽  
pp. 223-228 ◽  
Author(s):  
Hisanori YAMAMOTO ◽  
Kentaro HANADA ◽  
Masahiro NISHIJIMA
Keyword(s):  
Phospholipase C ◽  
Phospholipase D ◽  
Nuclear Translocation ◽  
Chinese Hamster ◽  
Nuclear Factor Κb ◽  
Short Chain ◽  
Nuclear Factor ◽  
Mouse Macrophage

Exposure of Chinese hamster CHO-K1 transfectant cells expressing mouse CD14 (CHO/CD14 cells) to lipopolysaccharide (LPS) induced rapid elevation of the cellular diacylglycerol (DAG) and choline/phosphocholine levels and nuclear translocation of nuclear factor κB (NFκB). When cells were incubated with short-chain DAG analogues or bacterial phospholipase C, NFκB activation occurred even without the LPS stimulus. Treatment of CHO/CD14 cells with tricyclo[5.2.1.02.6]decyl-(9[8])xanthogenate (D609), an inhibitor of phosphatidylcholine-specific phospholipase C and phospholipase D, almost completely inhibited not only the LPS-dependent production of DAG and choline/phosphocholine but also the LPS-dependent NFκB activation. In contrast, treatment of cells with 1-(6-{[3-methoxyoestra-1,3,5(10)-trien-17β-yl]-1H-pyrrole-2,5-dione (U73122), an inhibitor of phosphatidylinositol-specific phospholipase C in vitro, did not affect the LPS-dependent activation of NFκB. Production of DAG and activation of NFκB after the LPS stimulus were observed in mouse macrophage-like J774.1 cells, and this response to LPS by J774.1 cells was also inhibited by D609. These results suggest that the production of DAG from phosphatidylcholine was upstream of NFκB activation in response to a CD14-mediated LPS stimulus.

scholarly journals Bortezomib induces canonical nuclear factor-κB activation in multiple myeloma cells

Blood ◽  
2009 ◽  
Vol 114 (5) ◽  
pp. 1046-1052 ◽  
Author(s):  
Teru Hideshima ◽  
Hiroshi Ikeda ◽  
Dharminder Chauhan ◽  
Yutaka Okawa ◽  
Noopur Raje ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Molecular Mechanisms ◽  
Nuclear Translocation ◽  
Proteasome Inhibitors ◽  
Xenograft Model ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Down Regulation ◽  
Interacting Protein ◽  
Iκb Kinase

Bortezomib is a proteasome inhibitor with remarkable preclinical and clinical antitumor activity in multiple myeloma (MM) patients. The initial rationale for its use in MM was inhibition of nuclear factor (NF)-κB activity by blocking proteasomal degradation of inhibitor of κBα (IκBα). Bortezomib inhibits inducible NF-κB activity; however, its impact on constitutive NF-κB activity in MM cells has not yet been defined. In this study, we demonstrate that bortezomib significantly down-regulated IκBα expression and triggered NF-κB activation in MM cell lines and primary tumor cells from MM patients. Importantly, no inhibition of p65 (RelA) nuclear translocation was recognized after bortezomib treatment in a murine xenograft model bearing human MM cells. Bortezomib-induced NF-κB activation was mediated via the canonical pathway. Moreover, other classes of proteasome inhibitors also induced IκBα down-regulation associated with NF-κB activation. Molecular mechanisms whereby bortezomib induced IκBα down-regulation were further examined. Bortezomib triggered phosphorylation of IκB kinase (IKKβ) and its upstream receptor-interacting protein 2, whereas IKKβ inhibitor MLN120B blocked bortezomib-induced IκBα down-regulation and NF-κB activation, indicating receptor-interacting protein 2/IKKβ signaling plays crucial role in bortezomib-induced NF-κB activation. Moreover, IKKβ inhibitors enhanced bortezomib-induced cytotoxicity. Our studies therefore suggest that bortezomib-induced cytotoxicity cannot be fully attributed to inhibition of canonical NF-κB activity in MM cells.

scholarly journals Activation of nuclear factor-κB is necessary for myotrophin-induced cardiac hypertrophy

2002 ◽  
Vol 159 (6) ◽  
pp. 1019-1028 ◽  
Author(s):  
Sudhiranjan Gupta ◽  
Nicole H. Purcell ◽  
Anning Lin ◽  
Subha Sen
Keyword(s):  
Transcriptional Activity ◽  
Nuclear Translocation ◽  
Spontaneously Hypertensive Rat ◽  
Critical Role ◽  
Nuclear Factor Κb ◽  
Dominant Negative ◽  
Nuclear Factor ◽  
Hypertrophic Response ◽  
Calphostin C ◽  
Iκb Kinase

The transcription factor nuclear factor-κB (NF-κB) regulates expression of a variety of genes involved in immune responses, inflammation, proliferation, and programmed cell death (apoptosis). Here, we show that in rat neonatal ventricular cardiomyocytes, activation of NF-κB is involved in the hypertrophic response induced by myotrophin, a hypertrophic activator identified from spontaneously hypertensive rat heart and cardiomyopathic human hearts. Myotrophin treatment stimulated NF-κB nuclear translocation and transcriptional activity, accompanied by IκB-α phosphorylation and degradation. Consistently, myotrophin-induced NF-κB activation was enhanced by wild-type IκB kinase (IKK) β and abolished by the dominant-negative IKKβ or a general PKC inhibitor, calphostin C. Importantly, myotrophin-induced expression of two hypertrophic genes (atrial natriuretic factor [ANF] and c-myc) and also enhanced protein synthesis were partially inhibited by a potent NF-κB inhibitor, pyrrolidine dithio-carbamate (PDTC), and calphostin C. Expression of the dominant-negative form of IκB-α or IKKβ also partially inhibited the transcriptional activity of ANF induced by myotrophin. These findings suggest that the PKC–IKK–NF-κB pathway may play a critical role in mediating the myotrophin-induced hypertrophic response in cardiomyocytes.

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