Activation of nuclear transcription factor NF-kappaB by interleukin-1 is accompanied by casein kinase II-mediated phosphorylation of the p65 subunit

Quantitative Proteomics Reveal That CB2R Agonist JWH-133 Downregulates NF-κB Activation, Oxidative Stress, and Lysosomal Exocytosis from HIV-Infected Macrophages

HIV-associated neurocognitive disorders (HAND) affect 15-55% of HIV-positive patients and effective therapies are unavailable. HIV-infected monocyte-derived macrophages (MDM) invade the brain of these individuals, promoting neurotoxicity. We demonstrated an increased expression of cathepsin B (CATB), a lysosomal protease, in monocytes and post-mortem brain tissues of women with HAND. Increased CATB release from HIV-infected MDM leads to neurotoxicity, and their secretion is associated with NF-κB activation, oxidative stress, and lysosomal exocytosis. Cannabinoid receptor 2 (CB2R) agonist, JWH-133, decreases HIV-1 replication, CATB secretion, and neurotoxicity from HIV-infected MDM, but the mechanisms are not entirely understood. We hypothesized that HIV-1 infection upregulates the expression of proteins associated with oxidative stress and that a CB2R agonist could reverse these effects. MDM were isolated from healthy women donors (n = 3), infected with HIV-1ADA, and treated with JWH-133. After 13 days post-infection, cell lysates were labeled by Tandem Mass Tag (TMT) and analyzed by LC/MS/MS quantitative proteomics bioinformatics. While HIV-1 infection upregulated CATB, NF-κB signaling, Nrf2-mediated oxidative stress response, and lysosomal exocytosis, JWH-133 treatment downregulated the expression of the proteins involved in these pathways. Our results suggest that JWH-133 is a potential alternative therapy against HIV-induced neurotoxicity and warrant in vivo studies to test its potential against HAND.

Analyzing Sex-Specific Dimorphism in Human Skeletal Stem Cells

Sex-related differences are a current topic in contemporary science. In addition to hormonal regulation, cell-autonomous mechanisms are important in bone homeostasis and regeneration. In this study, human skeletal stem cells (SSCs) from female and male adults were cultured and analyzed with immunological assays and osteogenic differentiation assessments. Female SSCs exhibited a mean doubling time of 100.6 h, whereas male SSCs displayed a mean doubling time of 168.0 h. Immunophenotyping revealed the expression of the stem cell markers Nestin, CD133, and CD164, accompanied by the neural-crest marker SOX9. Furthermore, multiparameter flow cytometric analyses revealed a substantial population of multipotent SSCs, comprising up to 80% in both sexes. An analysis of the osteogenic differentiation potential demonstrated a strong mineralization in both male and female SSCs under physiological conditions. Recognizing the prevailing association of bone diseases with inflammatory processes, we also analyzed the osteogenic potential of SSCs from both sexes under pro-inflammatory conditions. Upon TNF-α and IL-1β treatment, we observed no sexual dimorphism on osteogenesis. In summary, we demonstrated the successful isolation and characterization of SSCs capable of rapid osteogenic differentiation. Taken together, in vitro cultured SSCs might be a suitable model to study sexual dimorphisms and develop drugs for degenerative bone diseases.

CSNK2A2 promotes hepatocellular carcinoma progression through activation of NF-κB pathway

INTRODUCTION AND OBJECTIVES

Breast and non-small cell lung cancers harbor an upregulated CSNK2A2 oncogene that encodes the protein kinase CK2 alpha', a catalytic subunit of the highly conserved serine/threonine kinase CK2. However, its role and biological significance in hepatocellular carcinoma (HCC) remains unclear.

MATERIALS AND METHODS

Western-blotting and immunohistochemistry were used to measure the expression of CSNK2A2 in HCC tumor tissues and cell lines. CCK8, Hoechst staining, transwell, tube formation assay in vitro and nude mice experiments in vivo were used to measure the effects of CSNK2A2 on HCC proliferation, apoptosis, metastasis, angiogenesis and tumor formation.

RESULTS

In the study, we showed that CSNK2A2 was highly expressed in HCC comparison with matched control tissues, and was linked with lower survival of patients. Additional experiments indicated that silencing of CSNK2A2 promoted HCC cell apoptosis, while inhibited HCC cells migrating, proliferating, angiogenesis both in vitro and in vivo. These effects were also accompanied by reduced expression of NF-κB target genes, including CCND1, MMP9 and VEGF. Moreover, treatment with PDTC counteracted the promotional effects of CSNK2A2 on HCC cells.

CONCLUSIONS

Overall, our results suggested that CSNK2A2 could promote HCC progression by activating the NF-κB pathway, and this could serve as a biomarker for future prognostic and therapeutic applications.

CDDO-Me Abrogates Aberrant Mitochondrial Elongation in Clasmatodendritic Degeneration by Regulating NF-κB-PDI-Mediated S-Nitrosylation of DRP1

Clasmatodendrosis is a kind of astroglial degeneration pattern which facilitates excessive autophagy. Although abnormal mitochondrial elongation is relevant to this astroglial degeneration, the underlying mechanisms of aberrant mitochondrial dynamics are still incompletely understood. Protein disulfide isomerase (PDI) is an oxidoreductase in the endoplasmic reticulum (ER). Since PDI expression is downregulated in clasmatodendritic astrocytes, PDI may be involved in aberrant mitochondrial elongation in clasmatodendritic astrocytes. In the present study, 26% of CA1 astrocytes showed clasmatodendritic degeneration in chronic epilepsy rats. 2-cyano-3,12-dioxo-oleana-1,9(11)-dien-28-oic acid methyl ester (CDDO-Me; bardoxolone methyl or RTA 402) and SN50 (a nuclear factor-κB (NF-κB) inhibitor) ameliorated the fraction of clasmatodendritic astrocytes to 6.8 and 8.1% in CA1 astrocytes, accompanied by the decreases in lysosomal-associated membrane protein 1 (LAMP1) expression and microtubule-associated protein 1A/1B light-chain 3 (LC3)-II/LC3-I ratio, indicating the reduced autophagy flux. Furthermore, CDDO-Me and SN50 reduced NF-κB S529 fluorescent intensity to 0.6- and 0.57-fold of vehicle-treated animal level, respectively. CDDO-Me and SN50 facilitated mitochondrial fission in CA1 astrocytes, independent of dynamin-related protein 1 (DRP1) S616 phosphorylation. In chronic epilepsy rats, total PDI protein, S-nitrosylated PDI (SNO-PDI), and SNO-DRP1 levels were 0.35-, 0.34- and 0.45-fold of control level, respectively, in the CA1 region and increased CDDO-Me and SN50. Furthermore, PDI knockdown resulted in mitochondrial elongation in intact CA1 astrocytes under physiological condition, while it did not evoke clasmatodendrosis. Therefore, our findings suggest that NF-κB-mediated PDI inhibition may play an important role in clasmatodendrosis via aberrant mitochondrial elongation.

Minor Kinases with Major Roles in Cytokinesis Regulation

Cytokinesis, the conclusive act of cell division, allows cytoplasmic organelles and chromosomes to be faithfully partitioned between two daughter cells. In animal organisms, its accurate regulation is a fundamental task for normal development and for preventing aneuploidy. Cytokinesis failures produce genetically unstable tetraploid cells and ultimately result in chromosome instability, a hallmark of cancer cells. In animal cells, the assembly and constriction of an actomyosin ring drive cleavage furrow ingression, resulting in the formation of a cytoplasmic intercellular bridge, which is severed during abscission, the final event of cytokinesis. Kinase-mediated phosphorylation is a crucial process to orchestrate the spatio-temporal regulation of the different stages of cytokinesis. Several kinases have been described in the literature, such as cyclin-dependent kinase, polo-like kinase 1, and Aurora B, regulating both furrow ingression and/or abscission. However, others exist, with well-established roles in cell-cycle progression but whose specific role in cytokinesis has been poorly investigated, leading to considering these kinases as "minor" actors in this process. Yet, they deserve additional attention, as they might disclose unexpected routes of cell division regulation. Here, we summarize the role of multifunctional kinases in cytokinesis with a special focus on those with a still scarcely defined function during cell cleavage. Moreover, we discuss their implication in cancer.

Protein kinase CK2 – diverse roles in cancer cell biology and therapeutic promise

The association of protein kinase CK2 (formerly casein kinase II or 2) with cell growth and proliferation in cells was apparent at early stages of its investigation. A cancer-specific role for CK2 remained unclear until it was determined that CK2 was also a potent suppressor of cell death (apoptosis); the latter characteristic differentiated its function in normal versus malignant cells because dysregulation of both cell growth and cell death is a universal feature of cancer cells. Over time, it became evident that CK2 exerts its influence on a diverse range of cell functions in normal as well as in transformed cells. As such, CK2 and its substrates are localized in various compartments of the cell. The dysregulation of CK2 is documented in a wide range of malignancies; notably, by increased CK2 protein and activity levels with relatively moderate change in its RNA abundance. High levels of CK2 are associated with poor prognosis in multiple cancer types, and CK2 is a target for active research and testing for cancer therapy. Aspects of CK2 cellular roles and targeting in cancer are discussed in the present review, with focus on nuclear and mitochondrial functions and prostate, breast and head and neck malignancies.

Evaluation of a Selective Chemical Probe Validates That CK2 Mediates Neuroinflammation in a Human Induced Pluripotent Stem Cell-Derived Microglial Model

Novel treatments for neurodegenerative disorders are in high demand. It is imperative that new protein targets be identified to address this need. Characterization and validation of nascent targets can be accomplished very effectively using highly specific and potent chemical probes. Human induced pluripotent stem cells (hiPSCs) provide a relevant platform for testing new compounds in disease relevant cell types. However, many recent studies utilizing this platform have focused on neuronal cells. In this study, we used hiPSC-derived microglia-like cells (MGLs) to perform side-by-side testing of a selective chemical probe, SGC-CK2-1, compared with an advanced clinical candidate, CX-4945, both targeting casein kinase 2 (CK2), one of the first kinases shown to be dysregulated in Alzheimer's disease (AD). CK2 can mediate neuroinflammation in AD, however, its role in microglia, the innate immune cells of the central nervous system (CNS), has not been defined. We analyzed available RNA-seq data to determine the microglial expression of kinases inhibited by SGC-CK2-1 and CX-4945 with a reported role in mediating inflammation in glial cells. As proof-of-concept for using hiPSC-MGLs as a potential screening platform, we used both wild-type (WT) MGLs and MGLs harboring a mutation in presenilin-1 (PSEN1), which is causative for early-onset, familial AD (FAD). We stimulated these MGLs with pro-inflammatory lipopolysaccharides (LPS) derived from E. coli and observed strong inhibition of the expression and secretion of proinflammatory cytokines by simultaneous treatment with SGC-CK2-1. A direct comparison shows that SGC-CK2-1 was more effective at suppression of proinflammatory cytokines than CX-4945. Together, these results validate a selective chemical probe, SGC-CK2-1, in human microglia as a tool to reduce neuroinflammation.

The Emerging Role of OTUB2 in Diseases: From Cell Signaling Pathway to Physiological Function

Ovarian tumor (OTU) domain-containing ubiquitin aldehyde-binding protein Otubain2 (OTUB2) was a functional cysteine protease in the OTU family with deubiquitinase activity. In recent years, with the wide application of molecular biology techniques, molecular mechanism regulation at multiple levels of cell signaling pathways has been gradually known, such as ubiquitin-mediated protein degradation and phosphorylation-mediated protein activation. OTUB2 is involved in the deubiquitination of many key proteins in different cell signaling pathways, and the effect of OTUB2 on human health or disease is not clear. OTUB2 is likely to cause cancer and other malignant diseases while maintaining normal human development and physiological function. Therefore, it is of great value to comprehensively understand the regulatory mechanism of OTUB2 and regard it as a target for the treatment of diseases. This review makes a general description and appropriate analysis of OTUB2's regulation in different cell signaling pathways, and connects OTUB2 with cancer from the research hotspot perspective of DNA damage repair and immunity, laying the theoretical foundation for future research.

The Immune Underpinnings of Barrett's-Associated Adenocarcinogenesis: a Retrial of Nefarious Immunologic Co-Conspirators

There is no doubt that chronic gastroesophageal reflux disease increases the risk of esophageal adenocarcinoma (EAC) by several fold (odds ratio, 6.4; 95% CI, 4.6-9.1), and some relationships between reflux disease-mediated inflammation and oncogenic processes have been explored; however, the precise interconnections between the immune response and genomic instabilities underlying these pathologic processes only now are emerging. Furthermore, the precise cell of origin of the precancerous stages associated with EAC development, Barrett's esophagus, be it cardia resident or embryonic remnant, may shape our interpretation of the likely immune drivers. This review integrates the current collective knowledge of the immunology underlying EAC development and outlines a framework connecting proinflammatory pathways, such as those mediated by interleukin 1β, tumor necrosis factor α, leukemia inhibitory factor, interleukin 6, signal transduction and activator of transcription 3, nuclear factor-κB, cyclooxygenase-2, and transforming growth factor β, with oncogenic pathways in the gastroesophageal reflux disease-Barrett's esophagus-EAC cancer sequence. Further defining these immune and molecular railroads may show a map of the routes taken by gastroesophageal cells on their journey toward EAC tumor phylogeny. The selective pressures applied by this immune-induced journey likely impact the phenotype and genotype of the resulting oncogenic destination and further exploration of lesser-defined immune drivers may be useful in future individualized therapies or enhanced selective application of recent immune-driven therapeutics.

How can a traffic light properly work if it is always green? The paradox of CK2 signaling

CK2 is a constitutively active protein kinase that assuring a constant level of phosphorylation to its numerous substrates supports many of the most important biological functions. Nevertheless, its activity has to be controlled and adjusted in order to cope with the varying needs of a cell, and several examples of a fine-tune regulation of its activity have been described. More importantly, aberrant regulation of this enzyme may have pathological consequences, e.g. in cancer, chronic inflammation, neurodegeneration, and viral infection. Our review aims at summarizing our current knowledge about CK2 regulation. In the first part, we have considered the most important stimuli shown to affect protein kinase CK2 activity/expression. In the second part, we focus on the molecular mechanisms by which CK2 can be regulated, discussing controversial aspects and future perspectives.

Dissecting the Regulatory Strategies of NF-κB RelA Target Genes in the Inflammatory Response Reveals Differential Transactivation Logics

Nuclear factor κB (NF-κB) RelA is the potent transcriptional activator of inflammatory response genes. We stringently defined a list of direct RelA target genes by integrating physical (chromatin immunoprecipitation sequencing [ChIP-seq]) and functional (RNA sequencing [RNA-seq] in knockouts) datasets. We then dissected each gene’s regulatory strategy by testing RelA variants in a primary-cell genetic-complementation assay. All endogenous target genes require RelA to make DNA-base-specific contacts, and none are activatable by the DNA binding domain alone. However, endogenous target genes differ widely in how they employ the two transactivation domains. Through model-aided analysis of the dynamic time-course data, we reveal the gene-specific synergy and redundancy of TA1 and TA2. Given that post-translational modifications control TA1 activity and intrinsic affinity for coactivators determines TA2 activity, the differential TA logics suggests context-dependent versus context-independent control of endogenous RelA-target genes. Although some inflammatory initiators appear to require co-stimulatory TA1 activation, inflammatory resolvers are a part of the NF-κB RelA core response.

Ngo et al. developed a genetic complementation system for NF-κB RelA that reveals that NF-κB target-gene selection requires high-affinity RelA binding and transcriptional activation domains for gene induction. The synergistic and redundant functions of two transactivation domains define pro-inflammatory and inflammation-response genes.

The Anti-Inflammatory Effect of KS23, A Novel Peptide Derived From Globular Adiponectin, on Endotoxin-Induced Uveitis in Rats

Purpose: Adiponectin has been shown to exert potent anti-inflammatory activities in a range of systemic inflammatory diseases. This study aimed to investigate the potential therapeutic effects of KS23, a globular adiponectin-derived peptide, on endotoxin-induced uveitis (EIU) in rats and lipopolysaccharide (LPS)-stimulated mouse macrophage-like RAW 264.7 cells.

Methods: EIU was induced in Lewis rats by subcutaneous injection of LPS into a single footpad. KS23 or phosphate-buffered saline (PBS) was administered immediately after LPS induction via intravitreal injection. Twenty-four hours later, clinical and histopathological scores were evaluated, and the aqueous humor (AqH) was collected to determine the infiltrating cells, protein concentration, and levels of inflammatory cytokines. In vitro, cultured RAW 264.7 cells were stimulated with LPS in the presence or absence of KS23, inflammatory cytokine levels in the supernatant, nuclear translocation of nuclear factor kappa B (NF-κB) subunit p65, and the expression of NF-kB signaling pathway components were analyzed.

Results: KS23 treatment significantly ameliorated the clinical and histopathological scores of EIU rats and reduced the levels of infiltration cells, protein, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the aqueous humor. Consistently, KS23 decreased the expression of TNF-α and IL-6 in the supernatant of LPS-stimulated RAW 264.7 cells and inhibited the LPS-induced nuclear translocation of NF-κB p65 and the phosphorylation of IKKα/β/IκBα/NF-κB.

Conclusion: The in vivo and in vitro results demonstrated the anti-inflammatory effects of the peptide KS23 and suggested that KS23 is a compelling, novel therapeutic candidate for the treatment of ocular inflammation.

Protein kinase 2 (CK2): a potential regulator of immune cell development and function in cancer

Protein kinase CK2, formally known as casein kinase II, is ubiquitously expressed and highly conserved serine/threonine or tyrosine kinase enzyme that regulates diverse signaling pathways responsible for cellular processes (i.e., cell proliferation and apoptosis) via interactions with over 500 known substrates. The enzyme's physiological interactions and cellular functions have been widely studied, most notably in the blood and solid malignancies. CK2 has intrinsic role in carcinogenesis as overexpression of CK2 subunits (α, α`, and β) and deregulation of its activity have been linked to various forms of cancers. CK2 also has extrinsic role in cancer stroma or in the tumor microenvironment (TME) including the immune cells. However, very few research studies have focused on extrinsic role of CK2 in regulating immune responses as a therapeutic alternative for cancer. The following review discusses CK2's regulation of key signaling events [Nuclear factor kappa B (NF-κB), Janus kinase/signal transducer and activators of transcription (JAK/STAT), Hypoxia inducible factor-1alpha (HIF-1α), Cyclooygenase-2 (COX-2), Extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK), Notch, Protein kinase B/AKT, Ikaros and Wnt] that can influence the development and function of immune cells in cancer. Potential clinical trials using potent CK2 inhibitors will facilitate and improve the treatment of human malignancies.

Cl-amidine attenuates lipopolysaccharide-induced mouse mastitis by inhibiting NF-κB, MAPK, NLRP3 signaling pathway and neutrophils extracellular traps release

Cl-amidine, a peptidylarginine deiminase inhibitor, has been shown to ameliorate the disease course and clinical manifestation in variety of disease models. Due to the beneficial effects of Cl-amidine, it has been becoming the hottest compound for the study in inflammatory diseases. However, the anti-inflammatory activity of Cl-amidine in lipopolysaccharide (LPS)-induced mouse mastitis remains unclear. In this study, we investigated the effects of Cl-amidine on LPS-induced mastitis mouse model. The mouse mastitis model was established by injection of LPS through the canals of the mammary gland. Cl-amidine was administered intraperitoneally 1 h before LPS treatment. The results showed that Cl-amidine significantly attenuated the damage of the mammary gland, which suppressed the activity of myeloperoxidase (MPO). The real-time PCR results indicated that Cl-amidine inhibited the production of TNF-α, IL-1β and IL-6 in LPS-induced mouse mastitis. Moreover, the western blot results indicated that Cl-amidine decreased the phosphorylation of IκB, p65, p38, ERK and the expression of NLRP3 in LPS-induced mouse mastitis. Furthermore, the neutrophils extracellular traps (NETs) were determined by Quant-iT picogreen dsDNA assay kit®, which suggested that Cl-amidine significantly inhibited the NETs in mouse serum. This study demonstrated that Cl-amidine decreased the pathological injury in LPS-induced mouse mastitis by inhibiting NF-κB, MAPK, NLRP3 signaling pathway and NETs release, which provides a potential candidate for the treatment of mastitis.

Tumor necrosis factor α-induced protein 1 as a novel tumor suppressor through selective downregulation of CSNK2B blocks nuclear factor-κB activation in hepatocellular carcinoma

Background

Tumor necrosis factor α-induced protein 1 (TNFAIP1) is frequently downregulated in cancer cell lines and promotes cancer cell apoptosis. However, its role, clinical significance and molecular mechanisms in hepatocellular carcinoma (HCC) are unknown.

Methods

The expression of TNFAIP1 in HCC tumor tissues and cell lines was measured by Western blot and immunohistochemistry. The effects of TNFAIP1 on HCC proliferation, apoptosis, metastasis, angiogenesis and tumor formation were evaluated by Cell Counting Kit-8 (CCK8), Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL), transwell, tube formation assay in vitro and nude mice experiments in vivo. The interaction between TNFAIP1 and CSNK2B was validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS), Co-immunoprecipitation and Western blot. The mechanism of how TNFAIP1 regulated nuclear factor-kappaB (NF-κB) pathway was analyzed by dual-luciferase reporter, immunofluorescence, quantitative Real-time polymerase chain reaction (RT-qPCR) and Western blot.

Findings

The TNFAIP1 expression is significantly decreased in HCC tissues and cell lines, and negatively correlated with the increased HCC histological grade. Overexpression of TNFAIP1 inhibits HCC cell proliferation, metastasis, angiogenesis and promotes cancer cell apoptosis both in vitro and in vivo, whereas the knockdown of TNFAIP1 in HCC cell displays opposite effects. Mechanistically, TNFAIP1 interacts with CSNK2B and promotes its ubiquitin-mediated degradation with Cul3, causing attenuation of CSNK2B-dependent NF-κB trans-activation in HCC cell. Moreover, the enforced expression of CSNK2B counteracts the inhibitory effects of TNFAIP1 on HCC cell proliferation, migration, and angiogenesis in vitro and in vivo.

Interpretation

Our results support that TNFAIP1 can act as a tumor suppressor of HCC by modulating TNFAIP1/CSNK2B/NF-κB pathway, implying that TNFAIP1 may represent a potential marker and a promising therapeutic target for HCC.

Protein Kinase CK2-A Putative Target for the Therapy of Diabetes Mellitus?

Since diabetes is a global epidemic, the development of novel therapeutic strategies for the treatment of this disease is of major clinical interest. Diabetes is differentiated in two types: type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). T1DM arises from an autoimmune destruction of insulin-producing β-cells whereas T2DM is characterized by an insulin resistance, an impaired insulin reaction of the target cells, and/or dysregulated insulin secretion. In the past, a growing number of studies have reported on the important role of the protein kinase CK2 in the regulation of the survival and endocrine function of pancreatic β-cells. In fact, inhibition of CK2 is capable of reducing cytokine-induced loss of β-cells and increases insulin expression as well as secretion by various pathways that are regulated by reversible phosphorylation of proteins. Moreover, CK2 inhibition modulates pathways that are involved in the development of diabetes and prevents signal transduction, leading to late complications such as diabetic retinopathy. Hence, targeting CK2 may represent a novel therapeutic strategy for the treatment of diabetes.

Roles of the hexosamine biosynthetic pathway and pentose phosphate pathway in bile acid-induced cancer development

Esophageal squamous cell carcinomas (ESCCs) as well as adenocarcinomas (EACs) were developed in rat duodenal contents reflux models (reflux model). The present study aimed to shed light on the mechanism by which bile acid stimulation causes cancer onset and progression. Metabolomics analyses were performed on samples of neoplastic and nonneoplastic tissues from reflux models, and K14D, cultivated from a nonmetastatic, primary ESCC, and ESCC‐DR, established from a metastatic thoracic lesion. ESCC‐DRtca2M was prepared by treating ESCC‐DR cells with taurocholic acid (TCA) to accelerate cancer progression. The lines were subjected to comprehensive genomic analyses. In addition, protein expression levels of glucose‐6‐phosphate dehydrogenase (G6PD), nuclear factor kappa B (NF‐κB) (p65) and O‐linked N‐Acetylglucosamine (O‐GlcNAc) were compared among lines. Cancers developed in the reflux models exhibited greater hexosamine biosynthesis pathway (HBP) activation compared with the nonneoplastic tissues. Expression of O‐GlcNAc transferase (OGT) increased considerably in both ESCC and EAC compared with nonneoplastic squamous epithelium. Conversely, cell line‐based experiments revealed the greater activation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. G6PD overexpression in response to TCA exposure was observed. Both NF‐κB (p65) and O‐GlcNAc were expressed more highly in ESCC‐DRtca2M than in the other cell lines. Moreover, ESCC‐DRtca2M cells had additional chromosomal abnormalities in excess of ESCC‐DR cells. Overall, glucose metabolism was upregulated in both esophageal cancer tissue and cell lines. While bile acids are not mutagenic, chronic exposure seems to trigger NF‐κB(p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression. Glucose metabolism was upregulated in both esophageal cancer tissue and cell lines, and the HBP was activated in the former. The cell line‐based experiments demonstrated upregulation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. While bile acids are not mutagenic, chronic exposure seems to trigger G6PD overexpression and NF‐κB (p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression.

Prostate cancer cells hyper-activate CXCR6 signaling by cleaving CXCL16 to overcome effect of docetaxel

Molecular reprogramming in response to chemotherapeutics leads to poor therapeutic outcomes for prostate cancer (PCa). In this study, we demonstrated that CXCR6-CXCL16 axis promotes DTX resistance and acts as a counter-defense mechanism. After CXCR6 activation, cell death in response to DTX was inhibited, and blocking of CXCR6 potentiated DTX cytotoxicity. Moreover, in response to DTX, PCa cells expressed higher CXCR6, CXCL16, and ADAM-10. Furthermore, ADAM-10-mediated release of CXCL16 hyper-activated CXCR6 signaling in response to DTX. Activation of CXCR6 resulted in increased GSK-3β, NF-κB, ERK1/2 phosphorylation, and survivin expression, which reduce DTX response. Finally, treatment of PCa cells with anti-CXCR6 monoclonal antibody synergistically or additively induced cell death with ∼1.5-4.5 fold reduction in the effective concentration of DTX. In sum, our data imply that co-targeting of CXCR6 would lead to therapeutic enhancement of DTX, leading to better clinical outcomes for PCa patients.

ASC-J9® increases the bladder cancer chemotherapy efficacy via altering the androgen receptor (AR) and NF-κB survival signals

Background

The current chemotherapy regimens may extend survival for patients with metastatic bladder cancer (BCa) for a few months, but eventually most patients succumb to disease because they develop resistance to their chemotherapy.

Methods

TCGA human clinical sample survey and urothelial tumor tissue microarrays (TMAs) were applied to investigate the expression of androgen receptor (AR) and NF-κB. Multiple BCa cell lines were used to test chemotherapy’s efficacy via multiple assays including XTT, flow cytometry, TUNEL, and BrdU incorporation. The effects of the AR degradation enhancer, ASC-J9®, combined with various chemotherapy reagents were examined both in vivo and in vitro.

Results

We unexpectedly found that in muscle-invasive BCa (miBCa) the signals of both the AR and NF-κB were increased via a TCGA sample survey. Results from multiple approaches revealed that targeting these two increased signals by combining various chemotherapeutic agents, including Cisplatin, Doxorubicin or Mitomycin C, with ASC-J9® led to increase the therapeutic efficacy. The combined therapy increases the expression of the pro-apoptosis BAX gene and cell cycle inhibitor p21 gene, yet suppresses the expression of the pro-survival BCL2 gene in miBCa cells. Preclinical studies using an in vivo mouse model with xenografted miBCa cells confirmed in vitro cell line data showing that treatment with ASC-J9® combined with Cisplatin can result in suppressing miBCa progression better than Cisplatin alone.

Conclusions

Together, these results support a novel therapeutic approach via combining Cisplatin with ASC-J9® to better suppress the progression of miBCa.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1258-0) contains supplementary material, which is available to authorized users.

Involvement of endothelial CK2 in the radiation induced perivascular resistant niche (PVRN) and the induction of radioresistance for non-small cell lung cancer (NSCLC) cells

BACKGROUND

Tumor microenvironment (TME) plays a vital role in determining the outcomes of radiotherapy. As an important component of TME, vascular endothelial cells are involved in the perivascular resistance niche (PVRN), which is formed by inflammation or cytokine production induced by ionizing radiation (IR). Protein kinase CK2 is a constitutively active serine/threonine kinase which plays a vital role in cell proliferation and inflammation. In this study, we investigated the potential role of CK2 in PVRN after IR exposure.

RESULT

Specific CK2 inhibitors, Quinalizarin and CX-4945, were employed to effectively suppressed the kinase activity of CK2 in human umbilical vein endothelial cells (HUVECs) without affecting their viability. Results showing that conditioned medium from IR-exposed HUVECs increased cell viability of A549 and H460 cells, and the pretreatment of CK2 inhibitors slowed down such increment. The secretion of IL-8 and IL-6 in HUVECs was induced after exposure with IR, but significantly inhibited by the addition of CK2 inhibitors. Furthermore, IR exposure elevated the nuclear phosphorylated factor-κB (NF-κB) p65 expression in HUVECs, which was a master factor regulating cytokine production. But when pretreated with CK2 inhibitors, such elevation was significantly suppressed.

CONCLUSION

This study indicated that protein kinase CK2 is involved in the key process of the IR induced perivascular resistant niche, namely cytokine production, by endothelial cells, which finally led to radioresistance of non-small cell lung cancer cells. Thus, the inhibition of CK2 may be a promising way to improve the outcomes of radiation in non-small cell lung cancer cells.

Mechanistic Insights into CpG DNA and IL-15 Synergy in Promoting B Cell Chronic Lymphocytic Leukemia Clonal Expansion

Malignant cell growth within patients with B cell chronic lymphocytic leukemia (B-CLL) is largely restricted to lymphoid tissues, particularly lymph nodes. The recent in vitro finding that TLR-9 ligand (oligodeoxynucleotide [ODN]) and IL-15 exhibit strong synergy in promoting B-CLL growth may be particularly relevant to growth in these sites. This study shows IL-15-producing cells are prevalent within B-CLL-infiltrated lymph nodes and, using purified B-CLL cells from blood, investigates the mechanism for ODN and IL-15 synergy in driving B-CLL growth. ODN boosts baseline levels of phospho-RelA(S529) in B-CLL and promotes NF-κB-driven increases in IL15RA and IL2RB mRNA, followed by elevated IL-15Rα and IL-2/IL-15Rβ (CD122) protein. IL-15→CD122 signaling during a critical interval, 20 to 36-48 h following initial ODN exposure, is required for optimal induction of the cycling process. Furthermore, experiments with neutralizing anti-IL-15 and anti-CD122 mAbs indicate that clonal expansion requires continued IL-15/CD122 signaling during cycling. The latter is consistent with evidence of heightened IL2RB mRNA in the fraction of recently proliferated B-CLL cells within patient peripheral blood. Compromised ODN+IL-15 growth with limited cell density is consistent with a role for upregulated IL-15Rα in facilitating homotypic trans IL-15 signaling, although there may be other explanations. Together, the findings show that ODN and IL-15 elicit temporally distinct signals that function in a coordinated manner to drive B-CLL clonal expansion.

Presenting a New Standard Drug Model for Turmeric and Its Prized Extract, Curcumin

Various parts of the turmeric plant have been used as medicinal treatment for various conditions from ulcers and arthritis to cardiovascular disease and neuroinflammation. The rhizome's curcumin extract is the most studied active constituent, which exhibits an expansive polypharmacology with influence on many key inflammatory markers. Despite the expansive reports of curcucmin's therapeutic value, clinical reliability and research repeatability with curcumin treatment are still poor. The pharmacology must be better understood and reliably mapped if curcumin is to be accepted and used in modern medical applications. Although the polypharmacology of this extract has been considered, in mainstream medicine, to be a drawback, a perspective change reveals a comprehensive and even synergistic shaping of the NF-kB pathway, including transactivation. Much of the inconsistent research data and unreliable clinical outcomes may be due to a lack of standardization which also pervades research standard samples. The possibility of other well-known curcumin by-products contributing in the polypharmacology is also discussed. A new flowchart of crosstalk in transduction pathways that lead to shaping of nuclear NF-kB transactivation is generated and a new calibration or standardization protocol for the extract is proposed which could lead to more consistent data extraction and improved reliability in therapy.

Dynamic phosphorylation of RelA on Ser42 and Ser45 in response to TNFα stimulation regulates DNA binding and transcription

The NF-κB signalling module controls transcription through a network of protein kinases such as the IKKs, as well as inhibitory proteins (IκBs) and transcription factors including RelA/p65. Phosphorylation of the NF-κB subunits is critical for dictating system dynamics. Using both non-targeted discovery and quantitative selected reaction monitoring-targeted proteomics, we show that the cytokine TNFα induces dynamic multisite phosphorylation of RelA at a number of previously unidentified residues. Putative roles for many of these phosphorylation sites on RelA were predicted by modelling of various crystal structures. Stoichiometry of phosphorylation determination of Ser45 and Ser42 revealed preferential early phosphorylation of Ser45 in response to TNFα. Quantitative analyses subsequently confirmed differential roles for pSer42 and pSer45 in promoter-specific DNA binding and a role for both of these phosphosites in regulating transcription from the IL-6 promoter. These temporal dynamics suggest that RelA-mediated transcription is likely to be controlled by functionally distinct NF-κB proteoforms carrying different combinations of modifications, rather than a simple ‘one modification, one effect’ system.

A rapid method for quantifying cytoplasmic versus nuclear localization in endogenous peripheral blood leukocytes by conventional flow cytometry

A biochemical system and method have been developed to enable the quantitative measurement of cytoplasmic versus nuclear localization within cells in whole blood. Compared with the analyses of nuclear localization by western blot or fluorescence microscopy, this system saves a lot of time and resources by eliminating the necessity of purification and culturing steps, and generates data that are free from the errors and artifacts associated with using tumor cell lines or calculating nuclear signals from 2D images. This user‐friendly system enables the analysis of cell signaling within peripheral blood cells in their endogenous environment, including measuring the kinetics of nuclear translocation for transcription factors without requiring protein modifications. We first demonstrated the efficiency and specificity of this system for targeting nuclear epitopes, and verified the results by fluorescence microscopy. Next, the power of the technique to analyze LPS‐induced signaling in peripheral blood monocytes was demonstrated. Finally, both FoxP3 localization and IL‐2‐induced STAT5 signaling in regulatory T cells were analyzed. We conclude that this system can be a useful tool for enabling multidimensional molecular‐biological analyses of cell signaling within endogenous peripheral blood cells by conventional flow cytometry. © 2017 The Authors. Cytometry Part A Published by Wiley Periodicals, Inc. on behalf of ISAC.

Protein Kinase CK2 Regulates Leukocyte-Endothelial Cell Interactions during Ischemia and Reperfusion in Striated Skin Muscle

BACKGROUND

Ischemia and reperfusion (I/R) causes tissue injury by inflammatory processes. This involves the upregulation of endothelial surface proteins by phospho-regulated signaling pathways, resulting in enhanced interactions of leukocytes with endothelial cells. Recently, we found that protein kinase CK2 is a crucial regulator of leukocyte-mediated inflammation. Therefore, in this study we investigated the involvement of CK2 in leukocyte-endothelial cell interactions during I/R injury.

METHODS

We first analyzed the inhibitory action of (E)-3-(2,3,4,5-tetrabromophenyl)acrylic acid (TBCA) and CX-4945 on CK2 kinase activity and the viability of human dermal microvascular endothelial cells (HDMEC). To mimic I/R conditions in vitro, HDMEC were exposed to hypoxia and reoxygenation and the expression of adhesion molecules was analyzed by flow cytometry. Moreover, we analyzed in vivo the effect of CK2 inhibition on leukocyte-endothelial cell interactions in the dorsal skinfold chamber model of I/R injury by means of repetitive intravital fluorescence microscopy and immunohistochemistry.

RESULTS

We found that TBCA and CX-4945 suppressed the activity of CK2 in HDMEC without affecting cell viability. This was associated with a significant downregulation of E-selectin and intercellular adhesion molecule (ICAM)-1 after in vitro hypoxia and reoxygenation. In vivo, CX-4945 treatment significantly decreased the numbers of adherent and transmigrated leukocytes in striated muscle tissue exposed to I/R.

CONCLUSION

Our findings indicate that CK2 is involved in the regulation of leukocyte-endothelial cell interactions during I/R by mediating the expression of E-selectin and ICAM-1.

The Regulation of NF-κB Subunits by Phosphorylation

The NF-κB transcription factor is the master regulator of the inflammatory response and is essential for the homeostasis of the immune system. NF-κB regulates the transcription of genes that control inflammation, immune cell development, cell cycle, proliferation, and cell death. The fundamental role that NF-κB plays in key physiological processes makes it an important factor in determining health and disease. The importance of NF-κB in tissue homeostasis and immunity has frustrated therapeutic approaches aimed at inhibiting NF-κB activation. However, significant research efforts have revealed the crucial contribution of NF-κB phosphorylation to controlling NF-κB directed transactivation. Importantly, NF-κB phosphorylation controls transcription in a gene-specific manner, offering new opportunities to selectively target NF-κB for therapeutic benefit. This review will focus on the phosphorylation of the NF-κB subunits and the impact on NF-κB function.

Increased occurrence of protein kinase CK2 in astrocytes in Alzheimer's disease pathology

BACKGROUND

Alzheimer's disease (AD) is the most common neurodegenerative disease. In addition to the occurrence of amyloid deposits and widespread tau pathology, AD is associated with a neuroinflammatory response characterized by the activation of microglia and astrocytes. Protein kinase 2 (CK2, former casein kinase II) is involved in a wide variety of cellular processes. Previous studies on CK2 in AD showed controversial results, and the involvement of CK2 in neuroinflammation in AD remains elusive.

METHODS

In this study, we used immunohistochemical and immunofluorescent staining methods to investigate the localization of CK2 in the hippocampus and temporal cortex of patients with AD and non-demented controls. We compared protein levels with Western blotting analysis, and we investigated CK2 activity in human U373 astrocytoma cells and human primary adult astrocytes stimulated with IL-1β or TNF-α.

RESULTS

We report increased levels of CK2 in the hippocampus and temporal cortex of AD patients compared to non-demented controls. Immunohistochemical analysis shows CK2 immunoreactivity in astrocytes in AD and control cases. In AD, the presence of CK2 immunoreactive astrocytes is increased. CK2 immunopositive astrocytes are associated with amyloid deposits, suggesting an involvement of CK2 in the neuroinflammatory response. In U373 cells and human primary astrocytes, the selective CK2 inhibitor CX-4945 shows a dose-dependent reduction of the IL-1β or TNF-α induced MCP-1 and IL-6 secretion.

CONCLUSIONS

This data suggests that CK2 in astrocytes is involved in the neuroinflammatory response in AD. The reduction in pro-inflammatory cytokine secretion by human astrocytes using the selective CK2 inhibitor CX-4945 indicates that CK2 could be a potential target to modulate neuroinflammation in AD.

Activation of MEK/ERK pathways through NF-κB activation is involved in interleukin-1β-induced cyclooxygenease-2 expression in canine dermal fibroblasts

The proinflammatory cytokine interleukin-1β (IL-1β) induced cyclooxygenases-2 (COX-2) mRNA expression and lipid mediator prostaglandin E2 release and in a time- and dose-dependent manner in canine dermal fibroblasts. The MEK inhibitor U0126 and the ERK inhibitor FR180204 clearly inhibited IL-1β-induced prostaglandin E2 release and COX-2 mRNA expression. IL-1β enhanced ERK1/2 phosphorylation, which was attenuated by inhibitors of MEK and ERK. The NF-κB inhibitor BAY 11-7082 also suppressed IL-1β-induced prostaglandin E2 release and COX-2 mRNA expression. Treatment of fibroblasts with IL-1β led to the phosphorylation of p65 and degradation of IκBα occurred, indicating that IL-1β treatment activated NF-κB. MEK and ERK1/2 inhibitors had no effect on the phosphorylation of p65 subunit induced by IL-1β, whereas the NF-κB inhibitor completely blocked IL-1β-induced phosphorylation of ERK1/2. We also observed that IκBα-knockdown enhanced the phosphorylation of p65 and ERK1/2. These findings suggest that stimulation of MEK/ERK signaling pathway by NF-κB activation regulates IL-1β-induced COX-2 expression and subsequent prostaglandin E2 release in canine dermal fibroblasts.

The protein kinase 2 inhibitor tetrabromobenzotriazole protects against renal ischemia reperfusion injury

Protein kinase 2 (CK2) activation was reported to enhance reactive oxygen species production and activate the nuclear factor κB (NF-κB) pathway. Because oxidative stress and inflammation are critical events for tissue destruction during ischemia reperfusion (I/R), we sought to determine whether CK2 was important in the renal response to I/R. Mice underwent 25 min of renal ischemia and were then reperfused. We confirmed an increased expression of CK2α during the reperfusion period, while expression of CK2β remained consistent. We administered tetrabromobenzotriazole (TBBt), a selective CK2α inhibitor before inducing I/R injury. Mice subjected to I/R injury showed typical patterns of acute kidney injury; blood urea nitrogen and serum creatinine levels, tubular necrosis and apoptosis, inflammatory cell infiltration and proinflammatory cytokine production, and oxidative stress were markedly increased when compared to sham mice. However, pretreatment with TBBt abolished these changes and improved renal function and architecture. Similar renoprotective effects of CK2α inhibition were observed for emodin. Renoprotective effects of CK2α inhibition were associated with suppression of NF-κB and mitogen activated protein kinase (MAPK) pathways. Taken together, these results suggest that CK2α mediates proapoptotic and proinflammatory signaling, thus the CK2α inhibitor may be used to prevent renal I/R injuries observed in clinical settings.

Lipopolysaccharide responsiveness in vocal fold fibroblasts

Background

Vocal fold fibroblast’s (VFF) strategic location in the lamina propria and their ability to respond to external stimuli by producing inflammatory molecules suggest their possible direct involvement in innate immunity. Toll-like receptors (TLRs) are an essential signaling component to this response, as they allow for recognition of various microorganisms, leading to subsequent induction of pro-inflammatory genes. The objective of this study was to elucidate the role of VFF in the host immune response and subsequent influence on inflammatory cytokine secretion.

Methods

VFF derived from polyp, scar, and normal tissue were treated with 5 μg/ml lipopolysaccharide (LPS). TLR1 through 9, CD14, and MD-2 were measured during stable conditions by polymerase chain reaction (PCR). Expression of TLR4 and IL-1R type-1 genes were quantified after 24 hrs LPS stimulation by reverse transcription-PCR. LPS responsiveness was determined by NF-κB nuclear translocation as measured by subunit p65 expression in nucleus with immunocytochemistry. Downstream effects were confirmed with immunoassay measuring IL-8 concentrations in supernatant after 8 hrs.

Results

All VFFs constitutively expressed TLR1 to 6, TLR9, CD14, and MD-2 mRNA. Polyp VFF exhibited significantly higher TLR4 transcript levels (p < 0.001) in comparison to scar and normal VFF. LPS stimulated scar and polyp VFF exhibited increased levels of p65 in the nucleus (p < 0.01) and secreted greater IL-8 protein (p < 0.0001) compared to normal VFF.

Conclusion

VFF constitutively express genes for the receptors essential to the host immune response. Scar and polyp VFF produced greater LPS responsiveness resulting in over-activated inflammatory patterns. These findings support VFF role in the pathogenesis of inflammatory vocal fold disorders and suggests their presence in the wound bed could lead to chronic inflammation.

Genistein inhibits phorbol ester-induced NF-κB transcriptional activity and COX-2 expression by blocking the phosphorylation of p65/RelA in human mammary epithelial cells

Genistein, an isoflavone present in soy products, has chemopreventive effects on mammary carcinogenesis. In the present study, we have investigated the effects of genistein on phorbol ester-induced expression of cyclooxygenase-2 (COX-2) that plays an important role in the pathophysiology of inflammation-associated carcinogenesis. Pretreatment of cultured human breast epithelial (MCF10A) cells with genistein reduced COX-2 expression induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). There are multiple lines of evidence supporting that the induction of COX-2 is regulated by the eukaryotic transcription factor NF-κB. Genistein failed to inhibit TPA-induced nuclear translocation and DNA binding of NF-κB as well as degradation of IκB. However, genistein abrogated the TPA-induced transcriptional activity of NF-κB as determined by the luciferase reporter gene assay. Genistein inhibited phosphorylation of the p65 subunit of NF-κB and its interaction with cAMP regulatory element-binding protein-binding protein (CBP)/p300 and TATA-binding protein (TBP). TPA-induced NF-κB phosphorylation was abolished by pharmacological inhibition of extracellular signal-regulated kinase (ERK). Likewise, pharmacologic inhibition or dominant negative mutation of ERK suppressed phosphorylation of p65. The above findings, taken together, suggest that genistein inhibits TPA-induced COX-2 expression in MCF10A cells by blocking ERK-mediated phosphorylation of p65 and its subsequent interaction with CBP and TBP.

A critical role for CK2 in cytokine-induced activation of NFκB in pancreatic β cell death

This study aimed to assess the role of constitutive protein kinase CK2 in cytokine-induced activation of NFκB in pancreatic β cell death. The CK2 inhibitors DRB (5,6-dichloro-1-β-D-ribofuranosylbenzimidazole) (50 μM) and DMAT (2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole) (5 μM), which decreased CK2 activity by approx. 65 %, rescued INS-1E β cells and mouse islets from cytokine (IL-1β, TNF-α plus IFN-γ)-induced β cell death without affecting H2O2- or palmitate-induced β cell death. Western blot analysis revealed that while DRB or DMAT did not influence cytokine-induced IκBα degradation, they inhibited NFκB-dependent IκBα resynthesis, demonstrating that cytokine-induced NFκB activity is dependent on CK2. Both DRB and DMAT inhibited the constitutive phosphorylation of NFκB p65 at serine 529, while leaving cytokine-induced phosphorylations of NFκB p65 at serines 276 and 536 unaltered. In comparison, putative phosphorylation sites for CK2 on HDACs 1, 2, and 3 at serines 421/423, 394, and 424, respectively, which may stimulate NFκB transcriptional activity, were unchanged by cytokines and CK2 inhibitors. Whereas IL-1β and TNF-α stimulate IκBα degradation and NFκB activation, IFN-γ potentiates cytokine-induced β cell death through activation of STAT1. DRB and DMAT inhibited IFN-γ-stimulated phosphorylation of STAT1 at serine 727, while leaving IFN-γ-induced phosphorylation of STAT1 at tyrosine 701 unaffected. Inhibition of cytokine-induced β cell death by CK2 inhibitors was, however, not dependent on IFN-γ, and IFN-γ did not affect CK2-dependent IκBα turnover. In conclusion, it is suggested that cytokine-induced activation of NFκB in β cells is dependent on CK2 activity, which phosphorylates NFκB p65 at serine 529.

Protein kinase CK2 inhibition down modulates the NF-κB and STAT3 survival pathways, enhances the cellular proteotoxic stress and synergistically boosts the cytotoxic effect of bortezomib on multiple myeloma and mantle cell lymphoma cells

CK2 is a pivotal pro-survival protein kinase in multiple myeloma that may likely impinge on bortezomib-regulated cellular pathways. In the present study, we investigated CK2 expression in multiple myeloma and mantle cell lymphoma, two bortezomib-responsive B cell tumors, as well as its involvement in bortezomib-induced cytotoxicity and signaling cascades potentially mediating bortezomib resistance. In both tumors, CK2 expression correlated with that of its activated targets NF-κB and STAT3 transcription factors. Bortezomib-induced proliferation arrest and apoptosis were significantly amplified by the simultaneous inhibition of CK2 with two inhibitors (CX-4945 and K27) in multiple myeloma and mantle cell lymphoma cell lines, in a model of multiple myeloma bone marrow microenvironment and in cells isolated from patients. CK2 inhibition empowered bortezomib-triggered mitochondrial-dependent cell death. Phosphorylation of NF-κB p65 on Ser529 (a CK2 target site) and rise of the levels of the endoplasmic reticulum stress kinase/endoribonuclease Ire1α were markedly reduced upon CK2 inhibition, as were STAT3 phospho Ser727 levels. On the contrary, CK2 inhibition increased phospho Ser51 eIF2α levels and enhanced the bortezomib-dependent accumulation of poly-ubiquitylated proteins and of the proteotoxic stress-associated chaperone Hsp70. Our data suggest that CK2 over expression in multiple myeloma and mantle cell lymphoma cells might sustain survival signaling cascades and can antagonize bortezomib-induced apoptosis at different levels. CK2 inhibitors could be useful in bortezomib-based combination therapies.

Vascular endothelial growth factor induces growth of uterine cervix and immune cell recruitment in mice

Knowledge of uterine cervical epithelial biology and factors that influence its events may be critical in understanding the process of cervical remodeling (CR). Here, we examine the impact of exogenous vascular endothelial growth factor (VEGF) on uterine cervical epithelial growth in mice (nonpregnant and pregnant) treated with VEGF agents (recombinant and inhibitor) using a variety of morphological and molecular techniques. Exogenous VEGF altered various uterine cervical epithelial cellular events, including marked induction of growth, edema, increase in inter-epithelial paracellular space, and recruitment of immune cells to the outer surface of epithelial cells (cervical lumen). We conclude that VEGF induces multiple alterations in the uterine cervical epithelial tissues that may play a role in local immune surveillance and uterine cervical growth during CR.

A genome-wide siRNA screen reveals positive and negative regulators of the NOD2 and NF-κB signaling pathways

The cytoplasmic receptor NOD2 (nucleotide-binding oligomerization domain 2) senses peptidoglycan fragments and triggers host defense pathways, including activation of nuclear factor κB (NF-κB) signaling, which lead to inflammatory immune responses. Dysregulation of NOD2 signaling is associated with inflammatory diseases, such as Crohn's disease and Blau syndrome. We used a genome-wide small interfering RNA screen to identify regulators of the NOD2 signaling pathway. Several genes associated with Crohn's disease risk were identified in the screen. A comparison of candidates from this screen with other "omics" data sets revealed interconnected networks of genes implicated in NF-κB signaling, thus supporting a role for NOD2 and NF-κB pathways in the pathogenesis of Crohn's disease. Many of these regulators were validated in secondary assays, such as measurement of interleukin-8 secretion, which is partially dependent on NF-κB. Knockdown of putative regulators in human embryonic kidney 293 cells followed by stimulation with tumor necrosis factor-α revealed that most of the genes identified were general regulators of NF-κB signaling. Overall, the genes identified here provide a resource to facilitate the elucidation of the molecular mechanisms that regulate NOD2- and NF-κB-mediated inflammation.

NF-κB, the first quarter-century: remarkable progress and outstanding questions

The ability to sense and adjust to the environment is crucial to life. For multicellular organisms, the ability to respond to external changes is essential not only for survival but also for normal development and physiology. Although signaling events can directly modify cellular function, typically signaling acts to alter transcriptional responses to generate both transient and sustained changes. Rapid, but transient, changes in gene expression are mediated by inducible transcription factors such as NF-κB. For the past 25 years, NF-κB has served as a paradigm for inducible transcription factors and has provided numerous insights into how signaling events influence gene expression and physiology. Since its discovery as a regulator of expression of the κ light chain gene in B cells, research on NF-κB continues to yield new insights into fundamental cellular processes. Advances in understanding the mechanisms that regulate NF-κB have been accompanied by progress in elucidating the biological significance of this transcription factor in various physiological processes. NF-κB likely plays the most prominent role in the development and function of the immune system and, not surprisingly, when dysregulated, contributes to the pathophysiology of inflammatory disease. As our appreciation of the fundamental role of inflammation in disease pathogenesis has increased, so too has the importance of NF-κB as a key regulatory molecule gained progressively greater significance. However, despite the tremendous progress that has been made in understanding the regulation of NF-κB, there is much that remains to be understood. In this review, we highlight both the progress that has been made and the fundamental questions that remain unanswered after 25 years of study.

Tumor necrosis factor-α-mediated threonine 435 phosphorylation of p65 nuclear factor-κB subunit in endothelial cells induces vasogenic edema and neutrophil infiltration in the rat piriform cortex following status epilepticus

BACKGROUND

Status epilepticus (SE) induces severe vasogenic edema in the piriform cortex (PC) accompanied by neuronal and astroglial damages. To elucidate the mechanism of SE-induced vasogenic edema, we investigated the roles of tumor necrosis factor (TNF)-α in blood-brain barrier (BBB) disruption during vasogenic edema and its related events in rat epilepsy models provoked by pilocarpine-induced SE.

METHODS

SE was induced by pilocarpine in rats that were intracerebroventricularly infused with saline-, and soluble TNF p55 receptor (sTNFp55R) prior to SE induction. Thereafter, we performed Fluoro-Jade B staining and immunohistochemical studies for TNF-α and NF-κB subunits.

RESULTS

Following SE, most activated microglia showed strong TNF-α immunoreactivity. In addition, TNF p75 receptor expression was detected in endothelial cells as well as astrocytes. In addition, only p65-Thr435 phosphorylation was increased in endothelial cells accompanied by SMI-71 expression (an endothelial barrier antigen). Neutralization of TNF-α by soluble TNF p55 receptor (sTNFp55R) infusion attenuated SE-induced vasogenic edema and neuronal damages via inhibition of p65-Thr435 phosphorylation in endothelial cells. Furthermore, sTNFp55R infusion reduced SE-induced neutrophil infiltration in the PC.

CONCLUSION

These findings suggest that impairments of endothelial cell functions via TNF-α-mediated p65-Thr 485 NF-κB phosphorylation may be involved in SE-induced vasogenic edema. Subsequently, vasogenic edema results in extensive neutrophil infiltration and neuronal-astroglial loss.

Basic principles and emerging concepts in the redox control of transcription factors

Convincing concepts of redox control of gene transcription have been worked out for prokaryotes and lower eukaryotes, whereas the knowledge on complex mammalian systems still resembles a patchwork of poorly connected findings. The article, therefore, reviews principles of redox regulation with special emphasis on chemical feasibility, kinetic requirements, specificity, and physiological context, taking well investigated mammalian transcription factor systems, nuclear transcription factor of bone marrow-derived lymphocytes (NF-κB), and kelch-like ECH-associated protein-1 (Keap1)/Nrf2, as paradigms. Major conclusions are that (i) direct signaling by free radicals is restricted to O(2)•- and •NO and can be excluded for fast reacting radicals such as •OH, •OR, or Cl•; (ii) oxidant signals are H(2)O(2), enzymatically generated lipid hydroperoxides, and peroxynitrite; (iii) free radical damage is sensed via generation of Michael acceptors; (iv) protein thiol oxidation/alkylation is the prominent mechanism to modulate function; (v) redox sensors must be thiol peroxidases by themselves or proteins with similarly reactive cysteine or selenocysteine (Sec) residues to kinetically compete with glutathione peroxidase (GPx)- and peroxiredoxin (Prx)-type peroxidases or glutathione-S-transferases, respectively, a postulate that still has to be verified for putative mammalian sensors. S-transferases and Prxs are considered for system complementation. The impact of NF-κB and Nrf2 on hormesis, management of inflammatory diseases, and cancer prevention is critically discussed.

Specification of DNA binding activity of NF-kappaB proteins

Nuclear factor-kappaB (NF-kappaB) is a pleiotropic mediator of inducible and specific gene regulation involving diverse biological activities including immune response, inflammation, cell proliferation, and death. The fine-tuning of the NF-kappaB DNA binding activity is essential for its fundamental function as a transcription factor. An increasing body of literature illustrates that this process can be elegantly and specifically controlled at multiple levels by different protein subsets. In particular, the recent identification of a non-Rel subunit of NF-kappaB itself provides a new way to understand the selective high-affinity DNA binding specificity of NF-kappaB conferred by a synergistic interaction within the whole complex. Here, we review the mechanism of the specification of DNA binding activity of NF-kappaB complexes, one of the most important aspects of NF-kappaB transcriptional control.

Activation of proinflammatory response in human intestinal epithelial cells following Vibrio cholerae infection through PI3K/Akt pathway

Vibrio cholerae activates proinflammatory response in cultured intestinal epithelial cells. In this study, we demonstrate that V. cholerae O395 infection of intestinal epithelial cells results in the activation of Akt. Inhibition of Akt significantly decreases IL-1alpha, IL-6, and TNF-alpha production in V. cholerae infected Int407 cells. Analysis of the mechanisms of Akt influences on cytokine response demonstrates that Akt promotes NF-kappaB activation. We have extended these findings to show that Akt activation may be regulated by bacterial genes associated with virulence, adherence, or motility. Insertion mutants in the virulence genes coding for CtxA, ToxT, and OmpU of V. cholerae modulate the activation of PI3K/Akt signaling pathway, whereas an aflagellate non-motile mutant (O395FLAN) and a adherent and less motile mutant (O395Y3N/O395Y4N) of V. cholerae both show very significant down-regulation of Akt activity in Int407 cells. Together, these observations indicate that Akt promotes proinflammatory cytokine production by V. cholerae infected human intestinal epithelial cells through its influences on NF-kappaB.

Crosstalk in inflammation: the interplay of glucocorticoid receptor-based mechanisms and kinases and phosphatases

Glucocorticoids (GCs) are steroidal ligands for the GC receptor (GR), which can function as a ligand-activated transcription factor. These steroidal ligands and derivatives thereof are the first line of treatment in a vast array of inflammatory diseases. However, due to the general surge of side effects associated with long-term use of GCs and the potential problem of GC resistance in some patients, the scientific world continues to search for a better understanding of the GC-mediated antiinflammatory mechanisms. The reversible phosphomodification of various mediators in the inflammatory process plays a key role in modulating and fine-tuning the sensitivity, longevity, and intensity of the inflammatory response. As such, the antiinflammatory GCs can modulate the activity and/or expression of various kinases and phosphatases, thus affecting the signaling efficacy toward the propagation of proinflammatory gene expression and proinflammatory gene mRNA stability. Conversely, phosphorylation of GR can affect GR ligand- and DNA-binding affinity, mobility, and cofactor recruitment, culminating in altered transactivation and transrepression capabilities of GR, and consequently leading to a modified antiinflammatory potential. Recently, new roles for kinases and phosphatases have been described in GR-based antiinflammatory mechanisms. Moreover, kinase inhibitors have become increasingly important as antiinflammatory tools, not only for research but also for therapeutic purposes. In light of these developments, we aim to illuminate the integrated interplay between GR signaling and its correlating kinases and phosphatases in the context of the clinically important combat of inflammation, giving attention to implications on GC-mediated side effects and therapy resistance.

Requirement for nuclear factor kappa B signalling in the interleukin-1-induced expression of the CCAAT/enhancer binding protein-delta gene in hepatocytes

Elevated circulating levels of acute phase proteins (APP) are associated with inflammation and inflammatory disorders such as cardiovascular disease. APP are mainly synthesised by hepatocytes and their transcription is induced by pro-inflammatory cytokines such as interleukin-1 (IL-1). The molecular mechanisms underlying the IL-1-induced expression of key transcription factors implicated in the regulation of APP are poorly understood. We have investigated this aspect using the CCAAT/enhancer binding protein-delta (C/EBPdelta) as a model gene. IL-1 induced the expression of C/EBPdelta mRNA and protein in the human hepatoma Hep3B cell line, a widely employed model system for studies on cytokine signalling in relation to the expression of APP. The IL-1-mediated induction of C/EBPdelta expression was attenuated in the presence of pharmacological inhibitors against c-Jun N-terminal kinase (JNK) (curcumin and SP600125), casein kinase 2 (CK2) (apigenin) and nuclear factor-kappaB (NF-kappaB) (NF-kappaB activation inhibitor). RNA interference assays showed significant attenuation of the IL-1-induced expression of C/EBPdelta following knockdown of the p50 and p65 subunits of NF-kappaB. IL-1 induced NF-kappaB DNA binding and activation by this transcription factor and this was attenuated by curcumin and apigenin. Taken together, these results suggest a potentially crucial role for NF-kappaB in the IL-1-induced expression of C/EBPdelta, and thereby downstream APP genes regulated by this transcription factor.

Lipid induced overexpression of NF-kappaB in skeletal muscle cells is linked to insulin resistance

Lipid induced NF-kappaB activation is known to be associated with insulin resistance and type2 diabetes. Here we show that incubation of L6 skeletal muscle cells with palmitate significantly increased NF-kappaB p65 and NF-kappaB p50 expression along with their phosphorylation. NF-kappaB p65 siRNA inhibited palmitate induced overexpression of NF-kappaB p65 indicating palmitate effect on transcriptional activation. RT-PCR and real time PCR experiments also showed a significant increase in NF-kappaB p65 gene expression due to palmitate. Overexpression of NF-kappaB p65 by palmitate was linked to impairment of insulin activity. Palmitate effect on NF-kappaB gene and protein expression was found to be mediated by phospho-PKCepsilon as calphostin C (an inhibitor of PKC) and epsilonV1 (PKCepsilon translocation inhibitor) significantly reduced NF-kappaB expression. To understand the underlying mechanism, we purified NF-kappaB and pPKCepsilon from palmitate incubated skeletal muscle cells and their interaction in cell free system demonstrated the transfer of phosphate from PKCepsilon to NF-kappaB. This prompted us to transduct pPKCepsilon to the skeletal muscle cells. These cells showed increased amount of pNF-kappaB and NF-kappaB. Excess of NF-kappaB p65 pool thus created in the cells made them insulin resistant. Addition of NF-kappaB p65 siRNA and SN50 inhibited palmitate induced NF-kappaB p65 expression indicating NF-kappaB regulation of its gene expression. Increase of NF-kappaB did not affect the activation of IKK/IkappaB indicating NF-kappaB p65 expression to be a distinct effect of palmitate. Since NF-kappaB p65 is linked to several diseases, including type2 diabetes, this report may be important in understanding the pathogenicity of these diseases.

The Ca2+-dependent protease Calpain A regulates Cactus/I kappaB levels during Drosophila development in response to maternal Dpp signals

Regulation of NF kappaB activity is central to many processes during development and disease. Activation of NF kappaB family members depends on degradation of inhibitory I kappaB proteins. In Drosophila, a nuclear gradient of the NF kappaB/c-rel protein Dorsal subdivides the embryonic dorsal-ventral axis, defining the extent and location of mesodermal and ectodermal territories. Activation of the Toll pathway directs Dorsal nuclear translocation by inducing proteosomal degradation of the I kappaB homologue Cactus. Another mechanism that impacts on Dorsal activation involves the Toll-independent pathway, which regulates constitutive Cactus degradation. We have shown that the BMP protein Decapentaplegic (Dpp) inhibits Cactus degradation independent of Toll. Here we report on a novel element of this pathway: the calcium-dependent protease Calpain A. Calpain A knockdowns increase Cactus levels, shifting the Dorsal gradient and dorsal-ventral patterning. As shown for mammalian I kappaB, this effect requires PEST sequences in the Cactus C-terminus, implying a conserved role for calpains. Alteration of Calpain A or dpp results in similar effects on Dorsal target genes. Epistatic analysis confirms Calpain A activity is regulated by Dpp, indicating that Dpp signals increase Cactus levels through Calpain A inhibition, thereby interfering with Dorsal activation. This mechanism may allow coordination of Toll, BMP and Ca(2+) signals, conferring precision to Dorsal-target expression domains.

Cloning and characterization of DULP, a novel ubiquitin-like molecule from human dendritic cells

We identified a novel ubiquitin-like molecule DULP from human dendritic cells. DULP contains a domain that shares 26% identity and 34% similarity with ubiquitin, and it possesses the corresponding Ile-44 hydrophobic patch used by mono- or poly-ubiquitin to interact with a ubiquitin-interaction motif (UIM) or ubiquitin-associated domain (UBA). Lysine residue corresponding to 6 of ubiquitin, which is involved in the formation of a multi-ubiquitin chain that can bind proteasomal subunit Rpn10/S5a, is also conserved in its ubiquitin-homology domain. However, DULP does not possess the highly conserved C-terminus Gly-Gly required for ubiquitin conjugation or the Lys-48 required for the formation of polyubiquitin chain to target substrates for degradation, suggesting it might be a novel ubiquitin-domain protein (UDP). DULP was found widely expressed in many cells and the ubiquitin-homology domain was not cleaved. We also confirmed that DULP expression was enriched in the nucleus and much weaker in the cytosol. Besides, we found that overexpression of DULP in 293T cells induced apoptosis, which might not be associated with the mitochondrial or proteasome pathway, with the specific mechanism remaining unclear. Further investigations are needed to identify the precise biological functions of DULP.

Mycobacterium bovis Bacillus Calmette-Guérin (BCG)-induced activation of PI3K/Akt and NF-kB signaling pathways regulates expression of CXCL10 in epithelial cells

CXCL10 production is a critical step in limiting mycobacterial infection. Although induction of this chemokine by mycobacteria in epithelial cells has been reported, it is still unclear how CXCL10 is regulated in Mycobacterium bovis BCG-infected epithelial cells. In this study, we demonstrate that phosphatidylinoditol 3-kinase (PI3K)/Akt and the nuclear factor kB (NF-kB) signaling pathways play an important role in CXCL10 expression at the protein and mRNA level in A549 cells. We demonstrate that treatment of A549 cells with LY294002 and wortmannin, two PI3K inhibitors, inhibited M. bovis BCG-induced CXCL10 expression. In addition, treatment of A549 cells with an Akt inhibitor significantly blocked M. bovis BCG-induced CXCL10 production. Moreover, our data show that treatment of epithelial cells with CAPE, BAY 11-7082, and PDTC three selective inhibitors of NF-kB, significantly reduced the effect of M. bovis BCG on induced CXCL10 mRNA expression (74%, 69% and 83% inhibition by 8microM CAPE, 10microM BAY 11-7082 and 3microM PDTC as assessed by real-time PCR, respectively). In accordance with the gene induction, the production of CXCL10 was also significantly reduced by these inhibitors. Finally, the inhibition of PI3K affect NF-kB activation in M. bovis BCG-infected cells, indicating that PI3K activity is required for the M. bovis BCG-induced activation of NF-kB. The functional association between PI3K/Akt and NF-kB demonstrates another mechanism in the regulation of M. bovis BCG-induced CXCL10 in A549 cells.