Colon cancer is the 3rd common malignancy and 4th common cause of cancer death in Korea. Recent studies have shown that abnormal inflammatory response plays a critical role in colon carcinogenesis. A striking example of connection between inflammation and cancer is NF-kappaB, in which key regulator of inflammation and immune response is associated with target for colon cancer treatment. Constitutive NF-kappaB expression in colon cancer is 40-80% in vivo as well as in vitro, and the inactivation of IKKbeta subunit can reduce tumor multiplicity. The possible mechanisms by which NF-kappaB can contribute to colon carcinogenesis include the activator of antiapoptotic gene expression, enhanced cell survival and proliferation, regulation of angiogenesis and promotion of metastasis of cancer cells. Recent insights into the role of NF-kappaB involved in colon cancer development as well as their relevance as therapeutic targets are herein discussed.
Colonic Neoplasms/*etiology/metabolism ; Humans ; I-kappa B Kinase/metabolism/physiology ; Inflammation ; NF-kappa B/metabolism/*physiology

I kappa B kinase beta (IKK beta) subunit of IKK complex is essential for the activation of NF-kappa B in response to various proinflammatory signals. Cys-179 in the activation loop of IKK beta is known to be the target site for IKK inhibitors such as cyclopentenone prostaglandins, arsenite, and antirheumatic gold compounds. Here we show that a mutant IKK beta in which Cys-179 is substituted with alanine had decreased activity when it was expressed in HEK-293 cells, and TNF stimulation did not restore the activity. Phosphorylation of activation loop serines (Ser-177 and Ser-181) which is required for IKK beta activation was reduced in the IKK beta (C179A) mutant. The activity of IKK beta (C179A) was partially recovered when its phosphorylation was enforced by coexpression with mitogen-activated protein kinase kinase kinases (MAPKKK) such as NF-kappa B inducing kinase (NIK) and MAPK/extracellular signal-regulated kinase kinase kinase 1(MEKK1) or when the serine residues were replaced with phospho-mimetic glutamate. The IKK beta (C179A) mutant was normal in dimer formation, while its activity abnormally responded to the change in the concentration of substrate ATP in reaction mixture. Our results suggest that Cys-179 of IKK beta plays a critical role in enzyme activation by promoting phosphorylation of activation-loop serines and interaction with ATP.
Transfection ; Serine/*metabolism ; Protein Binding ; Phosphorylation ; Mutant Proteins/chemistry ; MAP Kinase Kinase Kinases/metabolism ; I-kappa B Kinase/*chemistry ; Humans ; Hela Cells ; Enzyme Activation/*physiology ; Cysteine/*physiology ; Cells, Cultured ; Catalytic Domain ; Amino Acid Substitution/physiology ; Adenosine Triphosphate/metabolism

The NF-kappaB pathway regulates the expression of over 150 target genes, e.g., cytokines, chemokines, leukocyte adhesion molecules and inducible effector enzymes. Consequently, it plays a crucial role in innate and adaptive immune responses, inflammatory response, stress responses, apoptosis and so on. IkappaB kinase (IKK) is the key of this pathway, and it owns a special structure which consists of catalytic subunit and regulatory subunit. Naturally, the activation of IKK needs the interaction of the two subunits and phosphorylation by its upstream kinases. Actually, there are two methods of activation of the NF-kappaB pathway, and both of the methods need the IKK complex. Given to the crucial role of IKK, researchers have isolated and synthesized amounts of IKK inhibitors, and these provide a great convenience to develop novel anti-inflammatory and anti-tumor drugs.
Animals ; Anti-Inflammatory Agents ; pharmacology ; Antineoplastic Agents ; pharmacology ; Enzyme Activation ; Enzyme Inhibitors ; metabolism ; pharmacology ; Humans ; I-kappa B Kinase ; antagonists & inhibitors ; chemistry ; metabolism ; physiology ; NF-kappa B ; metabolism ; Phosphorylation ; Signal Transduction

<b>OBJECTIVEb>To investigate the role of TNF receptor-associated factor 2 (TRAF-2) and TRAF6 in CD40-induced nuclear factor-kappaB (NF-kappaB) signaling pathway and whether CD40 signaling requires TRAF2.

<b>METHODSb>Human B cell lines were transfected with plasmids expressing wild type TRAF2 or dominant negative TRAF2, TRAF2-shRNA, or TRAF6-shRNA. The activation of NF-kappaB was detected by Western blot, kinase assay, transfactor enzyme-linked immunosorbent assay (ELISA), and fluorescence resonance energy transfer (FRET). Analysis of the role of TRAF-2 and TRAF-6 in CD40-mediated NF-kappaB activity was examined following stimulation with recombinant CD154.

<b>RESULTSb>TRAF2 induced activity of IkappaB-kinases (IKKalpha, IKKi/epsilon), phosphorylation of IkappaBalpha, as well as nuclear translocation and phosphorylation of p65/RelA. In contrast, TRAF6 strongly induced NF-kappaB activation and nuclear translocation of p65 as well as p50 and c-Rel. Engagement of CD154-induced nuclear translocation of p65 was inhibited by a TRAF6-shRNA, but conversely was enhanced by a TRAF2-shRNA. Examination of direct interactions between CD40 and TRAFs by FRET documented that both TRAF2 and TRAF6 directly interacted with CD40. However, the two TRAFs competed for CD40 binding.

<b>CONCLUSIONSb>These results indicate that TRAF2 can signal in human B cells, but it is not essential for CD40-mediated NF-kappaB activation. Moreover, TRAF2 can compete with TRAF6 for CD40 binding, and thereby limit the capacity of CD40 engagement to induce NF-kappaB activation.

Animals ; B-Lymphocytes ; cytology ; physiology ; CD40 Antigens ; metabolism ; Cell Line ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Fluorescence Resonance Energy Transfer ; Humans ; I-kappa B Kinase ; metabolism ; NF-kappa B ; genetics ; metabolism ; Proto-Oncogene Proteins c-fos ; metabolism ; Signal Transduction ; physiology ; TNF Receptor-Associated Factor 2 ; genetics ; metabolism ; TNF Receptor-Associated Factor 6 ; genetics ; metabolism ; Transcription Factor RelA ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism

<b>BACKGROUNDb>Insulin resistance is an underlying feature of both type 2 diabetes and metabolic syndrome. Currently, it is unclear whether nuclear factor (NF)-&kappa;B inducing kinase (NIK) plays a role in the development of insulin resistance. The present in vivo study investigated the roles of NIK and I&kappa;B kinase α (IKKα) in obesity-induced insulin resistance using animal models.

<b>METHODSb>NIK expression was evaluated by Western blotting in male Lep(ob) mice and C57BL/6J mice fed a high-fat diet (HFD) (45% fat). After metformin and sulfasalazine treatment, NIK expression was investigated during the improvement of insulin resistance.

<b>RESULTSb>NIK was increased by about 1-fold in the renal tissues of Lep(ob) mice and C57BL/6J mice fed a HFD for 12 weeks. After 1 and 3 weeks of high-fat feeding, we observed an almost 50% decrease in NIK and IKKα expression in the liver and renal tissues of C57BL/6J mice. NIK expression was significantly lower in the liver and renal tissues of HFD-fed mice that were treated with insulin sensitizers, metformin and sulfasalazine. However, IKKα expression was increased after metformin treatment in both tissues.

<b>CONCLUSIONb>These results suggest a possible role of NIK in the liver and renal tissues of insulin-resistant mice.

Animals ; Blotting, Western ; Body Weight ; physiology ; Fasting ; blood ; Glucose Tolerance Test ; I-kappa B Kinase ; metabolism ; Insulin ; blood ; Insulin Resistance ; physiology ; Kidney ; metabolism ; Liver ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Obese ; Protein-Serine-Threonine Kinases ; metabolism

Intrinsic cellular defenses are non-specific antiviral activities by recognizing pathogen-associated molecular patterns (PAMPs). Toll-like receptors (TLRs), one of the pathogen recognize receptor (PRR), sense various microbial ligands. Especially, TLR2, TLR3, TLR4, TLR7, TLR8 and TLR9 recognize viral ligands such as glycoprotein, single- or double-stranded RNA and CpG nucleotides. The binding of viral ligands to TLRs transmits its signal to Toll/interleukin-1 receptor (TIR) to activate transcription factors via signal transduction pathway. Through activation of transcription factors, such as interferon regulatory factor-3, 5, and 7 (IRF-3, 5, 7) or nuclear factor-kappaB (NF-kappaB), type I interferons are induced, and antiviral proteins such as myxovirus-resistance protein (Mx) GTPase, RNA-dependent Protein Kinase (PKR), ribonuclease L (RNase L), Oligo-adenylate Synthetase (OAS) and Interferon Stimulated Gene (ISG) are further expressed. These antiviral proteins play an important role of antiviral resistancy against several viral pathogens in infected cells and further activate innate immune responses.
Animals ; GTP-Binding Proteins/metabolism ; Humans ; Interferon Regulatory Factors/metabolism ; Interferon Type I/*metabolism/physiology ; Models, Biological ; NF-kappa B/metabolism ; Toll-Like Receptors/metabolism ; Virus Diseases/*immunology/*metabolism/virology ; eIF-2 Kinase/metabolism

<b>AIMb>To determine how SDF-1 alpha/CXCR4 activates nuclear factor-kappa B (NF-kappaB) and promotes oral squamous cell carcinoma (OSCC) invasion.

<b>METHODOLOGYb>A lentivirus-based knockdown approach was utilized to deplete gene expression. NF-kappaB activation was evaluated by Western blot analysis and electrophoretic mobility shift (EMSA).

<b>RESULTSb>We show that the activation of NF-kappaB by CXCR4 occurs through the Carma3/Bcl10/Malt1 (CBM) complex in OSCC. We found that loss of components of the CBM complex in HNSCC can inhibit SDF-1 alpha induced phosphorylation and degradation of IkappaBalpha, while TNF alpha induced IKK activation remains unchanged. Further, we identified a role for novel and atypical, but not classical, PKCs in activating IKK through CXCR4. Importantly, inhibition of the CBM complex leads to a significant decrease in SDF-1 alpha mediated invasion of OSCC.

<b>CONCLUSIONb>The CBM complex plays a critical role in CXCR4-induced NF-kappaB activation in OSCC. Targeting molecular components of the NF-kappaB signaling pathway may provide an important therapeutic opportunity in controlling the progression and metastasis of OSCC mediated by SDF-1 alpha.

Adaptor Proteins, Signal Transducing ; antagonists & inhibitors ; physiology ; B-Cell CLL-Lymphoma 10 Protein ; CARD Signaling Adaptor Proteins ; antagonists & inhibitors ; physiology ; Carcinoma, Squamous Cell ; pathology ; Caspase Inhibitors ; Caspases ; physiology ; Cell Line, Tumor ; Chemokine CXCL12 ; antagonists & inhibitors ; physiology ; Enzyme Activation ; drug effects ; Gene Silencing ; Genetic Vectors ; genetics ; Humans ; I-kappa B Kinase ; drug effects ; I-kappa B Proteins ; metabolism ; Isoenzymes ; antagonists & inhibitors ; Lentivirus ; genetics ; Membrane Proteins ; antagonists & inhibitors ; physiology ; Mouth Neoplasms ; pathology ; Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein ; NF-KappaB Inhibitor alpha ; NF-kappa B ; antagonists & inhibitors ; physiology ; Neoplasm Invasiveness ; Neoplasm Proteins ; antagonists & inhibitors ; physiology ; Phosphorylation ; Plasmids ; genetics ; Protein Kinase C ; antagonists & inhibitors ; Receptors, CXCR4 ; physiology ; Tumor Necrosis Factor-alpha ; pharmacology

Human T cell leukemia virus type 1 (HTLV-1), an etiological factor that causes adult T cell leukemia and lymphoma (ATL), infects over 20 million people worldwide. About 1 million of HTLV-1-infected patients develop ATL, a highly aggressive non-Hodgkin's lymphoma without an effective therapy. The pX region of the HTLV-1 viral genome encodes an oncogenic protein, Tax, which plays a central role in transforming CD4+ T lymphocytes by deregulating oncogenic signaling pathways and promoting cell cycle progression. Expression of Tax following viral entry is critical for promoting survival and proliferation of human T cells and is required for initiation of oncogenesis. Tax exhibits diverse functions in host cells, and this oncoprotein primarily targets IκB kinase complex in the cytoplasm, resulting in persistent activation of NF-κB and upregulation of its responsive gene expressions that are crucial for T cell survival and cell cycle progression. We here review recent advances for the pathological roles of Tax in modulating IκB kinase activity. We also discuss our recent observation that Tax connects the IκB kinase complex to autophagy pathways. Understanding Tax-mediated pathogenesis will provide insights into development of new therapeutics in controlling HTLV-1-associated diseases.
Autophagy ; CD4-Positive T-Lymphocytes ; metabolism ; virology ; Cell Cycle ; Cell Transformation, Neoplastic ; genetics ; Gene Expression Regulation, Neoplastic ; Gene Products, tax ; genetics ; metabolism ; Human T-lymphotropic virus 1 ; physiology ; Humans ; I-kappa B Kinase ; genetics ; metabolism ; Leukemia-Lymphoma, Adult T-Cell ; genetics ; metabolism ; virology ; Membrane Microdomains ; metabolism ; virology ; NF-kappa B ; genetics ; metabolism ; Protein Binding ; Signal Transduction ; genetics

<b>OBJECTIVEb>To investigate the way of nuclear factor kappa B (NF-kappaB) activation and the mechanism of NF-kappaB-promoted proliferation in estrogen receptor (ER)-negative breast cancer cells.

<b>METHODSb>The protein of IkappaB kinase alpha (IKKalpha) was measured by Western blot and the influence on cell-cycle was assayed by flow cytometry (FCM).

<b>RESULTSb>The IKKalpha was tested higher in three ER-negative breast cancer cell lines than in MCF-7. The influence caused by epidermal growth factor (EGF), tumor necrosis factor (TNF)-alpha and E(2) to tumor cells' proliferation was tested. EGF could remarkably enhance cyclin D(1) expression about 83% more in EGF group than that in control group and proliferation index from 0.22 to 0.31 (P < 0.01). On the other hand, TNF-alpha inhibited cyclin D(1) expression. Protein kinase C inhibitor, Go6976, could peculiarly prevent NF-kappaB over-expression caused by EGF. The cell-cycle was assayed by FCM in phase G(0)/G(1) 69.36% and in phase S 22.77% when adding EGF and in phase G(0)/G(1) 91.54% and in phase S 7.81% when adding EGF and Go6976. The proliferation index decreased from 0.31 to 0.09 (P < 0.01).

<b>CONCLUSIONSb>EGF-EGFR pathway can provide ER-negative breast cancer cells the signal for the autonomous growth. This signal promoted tumor cells' proliferation is transmitted by activating NF-kappaB and expressing more cyclin D(1). In this pathway, NF-kappaB play an important role as signal transmitting. The strategy to NF-kappaB activating may provide new way to treat ER-negative breast cancers.

Breast Neoplasms ; metabolism ; pathology ; physiopathology ; Carbazoles ; pharmacology ; Cell Proliferation ; drug effects ; Cyclin D1 ; biosynthesis ; Epidermal Growth Factor ; pharmacology ; Estradiol ; pharmacology ; Female ; Humans ; I-kappa B Kinase ; metabolism ; Indoles ; pharmacology ; NF-kappa B ; metabolism ; physiology ; Receptors, Estrogen ; metabolism ; Signal Transduction ; Tumor Cells, Cultured ; Tumor Necrosis Factor-alpha ; pharmacology

Corn silk has been purified as an anticoagulant previously and the active component is a polysaccharide with a molecular mass of 135 kDa. It activates murine macrophages to induce nitric oxide synthase (NOS) and generate substantial amounts of NO in time and dose-dependent manners. It was detectable first at 15 h after stimulation by corn silk, peaked at 24 h, and undetectable by 48 h. Induction of NOS is inhibited by pyrolidine dithiocarbamate (PDTC) and genistein, an inhibitor of nuclear factor kappa B (NF-kappaB) and tyrosine kinase, respectively, indicating that iNOS stimulated by corn silk is associated with tyrosine kinase and NF-kappaB signaling pathways. IkappaB-alpha degradation was detectible at 10 min, and the level was restored at 120 min after treatment of corn silk. Corn silk induced nuclear translocation of NF-kappaB by phosphorylation and degradation of IkappaB-alpha.
Animals ; Anticoagulants/*pharmacology ; Genistein/pharmacology ; I-kappa B/metabolism ; Macrophages/drug effects/*enzymology/metabolism ; Mice ; NF-kappa B/antagonists & inhibitors/metabolism ; Nitric Oxide/biosynthesis ; Nitric-Oxide Synthase/antagonists & inhibitors/*biosynthesis ; Phosphorylation ; Plant Extracts/pharmacology ; Polysaccharides/*pharmacology ; Protein Transport/drug effects ; Protein-Tyrosine Kinase/antagonists & inhibitors/physiology ; Pyrrolidines/pharmacology ; Research Support, Non-U.S. Gov't ; Thiocarbamates/pharmacology ; Zea mays/*chemistry