NF-κB1, NF-κB2 and c-Rel differentially regulate susceptibility to colitis-associated adenoma development in C57BL/6 mice

Vitamin D3 Upregulated Protein 1 Deficiency Promotes Azoxymethane/Dextran Sulfate Sodium-Induced Colorectal Carcinogenesis in Mice

VDUP1 acts as a tumor suppressor gene in various cancers. VDUP1 is expressed at low levels in sporadic and ulcerative-colitis-associated colorectal cancer. However, the effects of VDUP1 deficiency on CAC remain unclear. In this study, we found that VDUP1 deficiency promoted CAC development in mice. Wild-type (WT) and VDUP1 KO mice were used to investigate the role of VDUP1 in the development of azoxymethane (AOM)- and dextran sulfate sodium (DSS)-induced CAC. VDUP1 levels significantly decreased in the colonic tumor and adjacent nontumoral tissues of WT mice after AOM/DSS treatment. Moreover, AOM/DSS-treated VDUP1 KO mice exhibited a worse survival rate, disease activity index, and tumor burden than WT mice. VDUP1 deficiency significantly induced cell proliferation and anti-apoptosis in tumor tissues of VDUP1 KO mice compared to WT littermates. Additionally, mRNA levels of interleukin-6 and tumor necrosis factor-alpha and active forms of signal transducer and activator of transcription 3 and nuclear factor-kappa B p65 were significantly increased in the tumor tissues of VDUP1 KO mice. Overall, this study demonstrated that the loss of VDUP1 promoted AOM/DSS-induced colon tumorigenesis in mice, highlighting the potential of VDUP1-targeting strategies for colon cancer prevention and treatment.

Dysregulation of Toll-Like Receptor Signaling-Associated Gene Expression in X-Linked Agammaglobulinemia: Implications for Correlations Genotype-Phenotype and Disease Expression

INTRODUCTION

In X-linked agammaglobulinemia (XLA), the diversity of BTK variants complicates the study of genotype-phenotype correlations. Since BTK negatively regulates toll-like receptors (TLRs), we investigated if distinct BTK mutation types selectively modulate TLR pathways, affecting disease expression.

METHODS

Using reverse transcription-quantitative polymerase chain reaction, we quantified ten TLR signaling-related genes in XLA patients with missense (n = 3) and nonsense (n = 5) BTK mutations and healthy controls (n = 17).

RESULTS

BTK, IRAK2, PIK3R4, REL, TFRC, and UBE2N were predominantly downregulated, while RIPK2, TLR3, TLR10, and TLR6 showed variable regulation. The missense XLA group exhibited significant downregulation of IRAK2, PIK3R4, REL, and TFRC and upregulation of TLR3 and/or TLR6.

CONCLUSION

Hypo-expression of TLR3, TLR6, and TLR10 may increase susceptibility to infections, while hyper-expression might contribute to chronic inflammatory conditions like arthritis or inflammatory bowel disease. Our findings shed light on the important inflammatory component characteristic of some XLA patients, even under optimal therapeutic conditions.

c-Rel is a Novel Oncogene in Lung Squamous Cell Carcinoma Regulating Cell Proliferation and Migration

Lung squamous cell carcinoma (LUSC) accounts for approximately 25% to 30% of lung cancers, but largely no targeted therapy is available against it, calling for identification of new oncogenes in LUSC growth for new therapeutic targets. In this study, REL was identified through a screening for oncogenes that are highly amplified in human LUSC. Its expression was associated with poor prognosis in LUSC patients. Furthermore, knockdown of c-Rel in LUSC cell lines lead to significant decrease in cell proliferation and migration. Mechanistically, c-Rel knockdown suppressed NFκB pathway by blocking phosphorylation of IκB. Consistently, pharmaceutic inhibition of c-Rel also. In orthotopic xenograft lung cancer mouse model, c-Rel knockdown inhibited the tumor growth. Cancer cell proliferation and epithelial-mesenchymal-transition (EMT) of the tumors were impaired by c-Rel knockdown. Finally, it's confirmed in precision-cut tumor slices of LUSC that deletion of c-Rel inhibits the NFκB pathway and cancer cell growth. Accordingly, we hypothesize that c-Rel promotes the activation of the NFκB pathway by promoting the phosphorylation of IκB in LUSC. Our study reveals REL as a novel LUSC oncogene and provides new insights into the molecular regulation of LUSC, which will provide new therapeutic targets for the treatment of squamous lung cancer.

The NF-κB signaling system in the immunopathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic, chronic condition characterized by episodes of inflammation in the gastrointestinal tract. The nuclear factor κB (NF-κB) system describes a family of dimeric transcription factors. Canonical NF-κB signaling is stimulated by and enhances inflammation, whereas noncanonical NF-κB signaling contributes to immune organogenesis. Dysregulation of NF-κB factors drives various inflammatory pathologies, including IBD. Signals from many immune sensors activate NF-κB subunits in the intestine, which maintain an equilibrium between local microbiota and host responses. Genetic association studies of patients with IBD and preclinical mouse models confirm the importance of the NF-κB system in host defense in the gut. Other studies have investigated the roles of these factors in intestinal barrier function and in inflammatory gut pathologies associated with IBD. NF-κB signaling modulates innate and adaptive immune responses and the production of immunoregulatory proteins, anti-inflammatory cytokines, antimicrobial peptides, and other tolerogenic factors in the intestine. Furthermore, genetic studies have revealed critical cell type-specific roles for NF-κB proteins in intestinal immune homeostasis, inflammation, and restitution that contribute to the etiopathology of IBD-associated manifestations. Here, we summarize our knowledge of the roles of these NF-κB pathways, which are activated in different intestinal cell types by specific ligands, and their cross-talk, in fueling aberrant intestinal inflammation. We argue that an in-depth understanding of aberrant immune signaling mechanisms may hold the key to identifying predictive or prognostic biomarkers and developing better therapeutics against inflammatory gut pathologies.

c-Rel-dependent Chk2 signaling regulates the DNA damage response limiting hepatocarcinogenesis

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death. The NF-κB transcription factor family subunit c-Rel is typically protumorigenic; however, it has recently been reported as a tumor suppressor. Here, we investigated the role of c-Rel in HCC.

APPROACH AND RESULTS

Histological and transcriptional studies confirmed expression of c-Rel in human patients with HCC, but low c-Rel expression correlated with increased tumor cell proliferation and mutational burden and was associated with advanced disease. In vivo , global ( Rel-/- ) and epithelial specific ( RelAlb ) c-Rel knockout mice develop more tumors, with a higher proliferative rate and increased DNA damage, than wild-type (WT) controls 30 weeks after N-diethylnitrosamine injury. However, tumor burden was comparable when c-Rel was deleted in hepatocytes once tumors were established, suggesting c-Rel signaling is important for preventing HCC initiation after genotoxic injury, rather than for HCC progression. In vitro , Rel-/- hepatocytes were more susceptible to genotoxic injury than WT controls. ATM-CHK2 DNA damage response pathway proteins were suppressed in Rel-/- hepatocytes following genotoxic injury, suggesting that c-Rel is required for effective DNA repair. To determine if c-Rel inhibition sensitizes cancer cells to chemotherapy, by preventing repair of chemotherapy-induced DNA damage, thus increasing tumor cell death, we administered single or combination doxorubicin and IT-603 (c-Rel inhibitor) therapy in an orthotopic HCC model. Indeed, combination therapy was more efficacious than doxorubicin alone.

CONCLUSION

Hepatocyte c-Rel signaling limits genotoxic injury and subsequent HCC burden. Inhibiting c-Rel as an adjuvant therapy increased the effectiveness of DNA damaging agents and reduced HCC growth.

Stromal inflammation, fibrosis and cancer: An old intuition with promising potential

It is now well established that the biology of cancer is influenced by not only malignant cells but also other components of the tumour microenvironment. Chronic inflammation and fibrosis have long been postulated to be involved in carcinogenesis. Chronic inflammation can promote tumorigenesis via growth factor/cytokine-mediated cellular proliferation, apoptotic resistance, immunosuppression; and free-radical-induced oxidative deoxyribonucleic acid damage. Fibrosis could cause a perturbation in the dynamics of the tumour microenvironment, potentially damaging the genome surveillance machinery of normal epithelial cells. In this review, we will provide an in-depth discussion of various diseases characterised by inflammation and fibrosis that have been associated with an increased risk of malignancy. In particular, we will present a comprehensive overview of the impact of alterations in stromal composition on tumorigenesis, induced as a consequence of inflammation and/or fibrosis. Strategies including the application of various therapeutic agents with stromal manipulation potential and targeted cancer screening for certain inflammatory diseases which can reduce the risk of cancer will also be discussed.

Nogo-B inhibition restricts ulcerative colitis via inhibiting p68/miR-155 signaling pathway

BACKGROUND & AIMS

Ulcerative colitis (UC) is a main type of inflammatory bowel diseases which spreads globally during the westernization of lifestyle over the past few decades. However, the cause of UC is still not fully understood. We aimed to disclose the role of Nogo-B in the development of UC.

METHODS

Nogo-deficiency (Nogo^-/-) and wild-type male mice were treated with dextran sodium sulfate (DSS) to conduct a UC model, followed by determination of colon and serum inflammatory cytokines level. RAW264.7, THP1 and NCM460 cells were used to determine macrophage inflammation as well as proliferation and migration of NCM460 cells under Nogo-B or miR-155 intervention.

RESULTS

Nogo deficiency significantly reduced DSS-induced weight loss, colon length and weight reduction, and inflammatory cells accumulation in the intestinal villus, while increased the expression of tight junctions (TJs) proteins (Zonula occludens-1, Occludin) and adherent junctions (AJs) proteins (E-cadherin, α-catenin), implying that Nogo deficiency attenuated DSS-induced UC. Mechanistically, Nogo-B deficiency reduced TNFα, IL-1β and IL-6 levels in the colon, serum, RAW264.7 cells and THP1-derived macrophages. Furthermore, we identified that Nogo-B inhibition can reduce the maturation of miR-155, which is essential for Nogo-B-affected inflammatory cytokines expression. Interestingly, we determined that Nogo-B and p68 can interact with each other to promote the expression and activation of Nogo-B and p68, thus facilitating miR-155 maturation to induce macrophage inflammation. Blocking p68 inhibited Nogo-B, miR-155, TNFα, IL-1β and IL-6 expression. Moreover, the culture medium collected from Nogo-B overexpressed macrophages can inhibit enterocytes NCM460 cells proliferation and migration.

CONCLUSION

We disclose that Nogo deficiency reduced DSS-induced UC via inhibiting p68-miR-155-activated inflammation. Our results indicate that Nogo-B inhibition serves as a new potential therapeutic candidate for the prevention and treatment of UC.

NF-kappa B expression in resected specimen of colonic cancer is higher compared to its expression in inflammatory bowel diseases and polyps

NF-Kappa B has a significant role in inflammatory processes as well as in colorectal cancer. The aim of this study was to compare the expression of NF-kappa B in colonic adenocarcinoma specimen, colonic adenomas and inflammatory colonic tissues. Patients with colorectal cancer (CRC), colonic adenomas and inflammatory processes undergoing surgery were recruited. Following a routine pathological evaluation tissue samples were stained using anti NF-κB monoclonal antibodies. Expression of NF-κB was quantified using IMAGEJ program for immunohistochemistry staining. Samples were also stained and quantified for CEA expression. Fifty-six patients were included. 30 cancers, 6 polyps and 20 inflammatory processes. Expression of NF-κB was similar between polypoid and inflammation etiologies. However, it was significantly higher in CRC compared to both (p < 0.05). In cancer patients, NF-κB expression in the resection margins was correlated with positive node status. CEA expression was higher in the cancer group, less in the IBD group and the lowest in the colonic non diseased margins. Our results provide a supportive evidence that NF-κB pathway is strongly involved in colon cancer development and metastasis. Interestingly, expression of NF-κB in benign polypoid lesions was as high as in inflammatory etiologies. This support the role of NF-κB early in the adenoma to carcinoma sequence. Further research is needed to evaluate the exact role of NF-κB in tumor progression in order to look for diagnostic and therapeutic possibilities.

Nfkb2 deficiency and its impact on plasma cells and immunoglobulin expression in murine small intestinal mucosa

The alternative (noncanonical) nuclear factor-κB (NF-κB) signaling pathway predominantly regulates the function of the p52/RelB heterodimer. Germline Nfkb2 deficiency in mice leads to loss of p100/p52 protein and offers protection against a variety of gastrointestinal conditions, including azoxymethane/dextran sulfate sodium (DSS)-induced colitis-associated cancer and lipopolysaccharide (LPS)-induced small intestinal epithelial apoptosis. However, the common underlying protective mechanisms have not yet been fully elucidated. We applied high-throughput RNA-Seq and proteomic analyses to characterize the transcriptional and protein signatures of the small intestinal mucosa of naïve adult Nfkb2^-/- mice. Those data were validated by immunohistochemistry and quantitative ELISA using both small intestinal tissue lysates and serum. We identified a B-lymphocyte defect as a major transcriptional signature in the small intestinal mucosa and immunoglobulin A as the most downregulated protein by proteomic analysis in Nfkb2^-/- mice. Small intestinal immunoglobulins were dramatically dysregulated, with undetectable levels of immunoglobulin A and greatly increased amounts of immunoglobulin M being detected. The numbers of IgA-producing, cluster of differentiation (CD)138-positive plasma cells were also reduced in the lamina propria of the small intestinal villi of Nfkb2^-/- mice. This phenotype was even more striking in the small intestinal mucosa of RelB^-/- mice, although these mice were equally sensitive to LPS-induced intestinal apoptosis as their RelB^+/+ wild-type counterparts. NF-κB2/p52 deficiency confers resistance to LPS-induced small intestinal apoptosis and also appears to regulate the plasma cell population and immunoglobulin levels within the gut.NEW & NOTEWORTHY Novel transcriptomic analysis of murine proximal intestinal mucosa revealed an unexpected B cell signature in Nfkb2^-/- mice. In-depth analysis revealed a defect in the CD38+ B cell population and a gut-specific dysregulation of immunoglobulin levels.

p50 suppresses cytotoxic T lymphocyte effector function to regulate tumor immune escape and response to immunotherapy

Background

NF-κB is a key link between inflammation and cancer. Previous studies of NF-κB have largely focused on tumor cells, and the intrinsic function of NF-κB in T cells in tumor development and response to immunotherapy is largely unknown. We aimed at testing the hypothesis that NF-κB1 (p50) activation in T cells underlies human colon cancer immune escape and human cancer non-response to anti-PD-1 immunotherapy.

Methods

We screened NF-κB activation in human colon carcinoma and used mouse models to determine p50 function in tumor cells and immune cells. RNA-Seq was used to identify p50 target genes. p50 binding to target gene promoters were determined by electrophoresis mobility shift assay and chromatin immunoprecipitation. A p50 activation score was generated from gene expression profiling and used to link p50 activation to T-cell activation and function pre-nivolumab and post-nivolumab immunotherapy in human patients with cancer.

Results

p50 is the dominant form of NF-κB that is highly activated in immune cells in the human colorectal carcinoma microenvironment and neighboring non-neoplastic colon epithelial cells. Tumor cell intrinsic p50 signaling and T-cell intrinsic p50 signaling exert opposing functions in tumor growth control in vivo. Deleting Nfkb1 in tumor cells increased whereas in T cells decreased tumor growth in preclinical mouse models. Gene expression profiling identified Gzmb as a p50 target in T cells. p50 binds directly to a previously uncharacterized κB sequence at the Gzmb promoter in T cells, resulting in repression of Gzmb expression in tumor-infiltrating cytotoxic T lymphocytes (CTLs) to induce a dysfunctional CTL phenotype to promote tumor immune escape. p50 activation is inversely correlated with both GZMB expression and T-cell tumor infiltration in human colorectal carcinoma. Furthermore, nivolumab immunotherapy decreased p50 activation and increased GZMB expression in human patients with melanoma.

Conclusions

Inflammation activates p50 that binds to the Gzmb promoter to repress granzyme B expression in T cells, resulting in CTL dysfunction to confer tumor immune escape and decreased response to anti-PD-1 immunotherapy.

An epithelial Nfkb2 pathway exacerbates intestinal inflammation by supplementing latent RelA dimers to the canonical NF-κB module

Aberrant inflammation, such as that associated with inflammatory bowel disease (IBD), is fueled by the inordinate activity of RelA/NF-κB factors. As such, the canonical NF-κB module mediates controlled nuclear activation of RelA dimers from the latent cytoplasmic complexes. What provokes pathological RelA activity in the colitogenic gut remains unclear. The noncanonical NF-κB pathway typically promotes immune organogenesis involving Nfkb2 gene products. Because NF-κB pathways are intertwined, we asked whether noncanonical signaling aggravated inflammatory RelA activity. Our investigation revealed frequent engagement of the noncanonical pathway in human IBD. In a mouse model of experimental colitis, we established that Nfkb2-mediated regulations escalated the RelA-driven proinflammatory gene response in intestinal epithelial cells, exacerbating the infiltration of inflammatory cells and colon pathologies. Our mechanistic studies clarified that cell-autonomous Nfkb2 signaling supplemented latent NF-κB dimers, leading to a hyperactive canonical RelA response in the inflamed colon. In sum, the regulation of latent NF-κB dimers appears to link noncanonical Nfkb2 signaling to RelA-driven inflammatory pathologies and may provide for therapeutic targets.

Inhibitor of apoptosis-stimulating p53 protein protects against inflammatory bowel disease in mice models by inhibiting the nuclear factor kappa B signaling

Drugs and therapies available for the treatment of inflammatory bowel disease (IBD) are not satisfactory. Our previous study has established the inhibitor of apoptosis-stimulating p53 protein (iASPP) as an oncogenic regulator in colorectal cancer by forming a regulatory axis or feedback loop with miR-124, p53, or p63. As iASPP could target and inhibit nuclear factor kappa B (NF-κB) activation, in this study the role and mechanism of iASPP in IBD was investigated. The aberrant up-regulation of iASPP in IBD was subsequently confirmed, based on online data sets, clinical sample examinations and 2,4,6-trinitrobenzene sulfonic acid (TNBS)- and dextran sulfate sodium (DSS)-induced colitis mice models. TNBS or DSS stimulation successfully induced colon shortness, body weight loss, mice colon oxidative stress and inflammation. In both types of colitis mice models, iASPP over-expression improved, whereas iASPP knockdown aggravated TNBS or DSS stimulation-caused colon shortness, body weight loss and mice colon oxidative stress and inflammation. Meanwhile, in both types of colitis mice models, iASPP over-expression inhibited p65 phosphorylation and decreased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, C-X-C motif chemokine ligand (CXCL)1 and CXCL2 in mice colons, whereas iASPP knockdown exerted opposite effects.

Probiogenomics of Lactobacillus delbrueckii subsp. lactis CIDCA 133: In Silico, In Vitro, and In Vivo Approaches

Lactobacillus delbrueckii subsp. lactis CIDCA 133 (CIDCA 133) has been reported as a potential probiotic strain, presenting immunomodulatory properties. This study investigated the possible genes and molecular mechanism involved with a probiotic profile of CIDCA 133 through a genomic approach associated with in vitro and in vivo analysis. Genomic analysis corroborates the species identification carried out by the classical microbiological method. Phenotypic assays demonstrated that the CIDCA 133 strain could survive acidic, osmotic, and thermic stresses. In addition, this strain shows antibacterial activity against Salmonella Typhimurium and presents immunostimulatory properties capable of upregulating anti-inflammatory cytokines Il10 and Tgfb1 gene expression through inhibition of Nfkb1 gene expression. These reported effects can be associated with secreted, membrane/exposed to the surface and cytoplasmic proteins, and bacteriocins-encoding genes predicted in silico. Furthermore, our results showed the genes and the possible mechanisms used by CIDCA 133 to produce their beneficial host effects and highlight its use as a probiotic microorganism.

NF-κB2 and RELB offer prognostic information in colorectal cancer and NFKB2 rs7897947 represents a genetic risk factor for disease development

The Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) family of transcription factors plays an important role in immune responses and cancer development and progression. We have focused on NF-κB2 and RELB of the alternative pathway of NF-κB, which remains largely underexplored in colorectal cancer (CRC). We found that NF-κB2 and RELB protein levels were upregulated in tumour and surrounding stromal tissue compared to distant non-neoplastic tissue (NN) and associated stroma (p<0.001 in all associations). Moreover, low RELB protein expression was associated with decreased overall survival (p = 0.032). Lower RELB gene expression levels were observed in tumour compared to NN tissue (p = 0.003) and were associated with shorter time to progression (TTP) (p = 0.025). NF-κB2 gene expression levels were similar in tumour and NN tissue, but higher tumour levels were prognostic for improved survival (p = 0.038) and TTP (p<0.001). We also assessed the significance of two NF-κB2 genetic polymorphisms, rs12769316 and rs7897947. Both polymorphisms were associated with lymph node infiltration (p = 0.045 and p = 0.009, respectively). In addition, rs12769316 AA homozygotes relapsed less often compared to G allele carriers (p = 0.029). Moreover, rs7897947 allele frequencies differed significantly between CRC patients and healthy controls (p<0.001) and the minor allele (G) was associated with reduced risk for developing CRC (p<0.001, OR: 0.527, 95% CI: 0.387-0.717). In conclusion, the alternative NF-κB pathway appears deregulated in CRC. Moreover, NF-κB2 and RELB expression levels seem to be significant for the clinical outcome of CRC patients and rs7897947 appears to be a risk factor for CRC development.

Using systems medicine to identify a therapeutic agent with potential for repurposing in inflammatory bowel disease

Inflammatory bowel diseases (IBDs) cause significant morbidity and mortality. Aberrant NF-κB signalling is strongly associated with these conditions, and several established drugs influence the NF-κB signalling network to exert their effect. This study aimed to identify drugs that alter NF-κB signalling and could be repositioned for use in IBD. The SysmedIBD Consortium established a novel drug-repurposing pipeline based on a combination of in silico drug discovery and biological assays targeted at demonstrating an impact on NF-κB signalling, and a murine model of IBD. The drug discovery algorithm identified several drugs already established in IBD, including corticosteroids. The highest-ranked drug was the macrolide antibiotic clarithromycin, which has previously been reported to have anti-inflammatory effects in aseptic conditions. The effects of clarithromycin effects were validated in several experiments: it influenced NF-κB-mediated transcription in murine peritoneal macrophages and intestinal enteroids; it suppressed NF-κB protein shuttling in murine reporter enteroids; it suppressed NF-κB (p65) DNA binding in the small intestine of mice exposed to lipopolysaccharide; and it reduced the severity of dextran sulphate sodium-induced colitis in C57BL/6 mice. Clarithromycin also suppressed NF-κB (p65) nuclear translocation in human intestinal enteroids. These findings demonstrate that in silico drug repositioning algorithms can viably be allied to laboratory validation assays in the context of IBD, and that further clinical assessment of clarithromycin in the management of IBD is required.This article has an associated First Person interview with the joint first authors of the paper.

IL22BP Mediates the Antitumor Effects of Lymphotoxin Against Colorectal Tumors in Mice and Humans

BACKGROUND & AIMS

Unregulated activity of interleukin (IL) 22 promotes intestinal tumorigenesis in mice. IL22 binds the antagonist IL22 subunit alpha 2 (IL22RA2, also called IL22BP). We studied whether alterations in IL22BP contribute to colorectal carcinogenesis in humans and mice.

METHODS

We obtained tumor and nontumor tissues from patients with colorectal cancer (CRC) and measured levels of cytokines by quantitative polymerase chain reaction, flow cytometry, and immunohistochemistry. We measured levels of Il22bp messenger RNA in colon tissues from wild-type, Tnf^-/-, Lta^-/-, and Ltb^-/- mice. Mice were given azoxymethane and dextran sodium sulfate to induce colitis and associated cancer or intracecal injections of MC38 tumor cells. Some mice were given inhibitors of lymphotoxin beta receptor (LTBR). Intestine tissues were analyzed by single-cell sequencing to identify cell sources of lymphotoxin. We performed immunohistochemistry analysis of colon tissue microarrays from patients with CRC (1475 tissue cores, contained tumor and nontumor tissues) and correlated levels of IL22BP with patient survival times.

RESULTS

Levels of IL22BP were decreased in human colorectal tumors, compared with nontumor tissues, and correlated with levels of lymphotoxin. LTBR signaling was required for expression of IL22BP in colon tissues of mice. Wild-type mice given LTBR inhibitors had an increased tumor burden in both models, but LTBR inhibitors did not increase tumor growth in Il22bp^-/- mice. Lymphotoxin directly induced expression of IL22BP in cultured human monocyte-derived dendritic cells via activation of nuclear factor κB. Reduced levels of IL22BP in colorectal tumor tissues were associated with shorter survival times of patients with CRC.

CONCLUSIONS

Lymphotoxin signaling regulates expression of IL22BP in colon; levels of IL22BP are reduced in human colorectal tumors, associated with shorter survival times. LTBR signaling regulates expression of IL22BP in colon tumors in mice and cultured human dendritic cells. Patients with colorectal tumors that express low levels of IL22BP might benefit from treatment with an IL22 antagonist.

The Role of Shcbp1 in Signaling and Disease

Src homolog and collagen homolog (Shc) proteins have been identified as adapter proteins associated with cell surface receptors and have been shown to play important roles in signaling and disease. Shcbp1 acts as a Shc SH2-domain binding protein 1 and is involved in the regulation of signaling pathways, such as FGF, NF-κB, MAPK/ERK, PI3K/AKT, TGF-β1/Smad and β -catenin signaling. Shcbp1 participates in T cell development, the regulation of downstream signal transduction pathways, and cytokinesis during mitosis and meiosis. In addition, Shcbp1 has been demonstrated to correlate with Burkitt-like lymphoma, breast cancer, lung cancer, gliomas, synovial sarcoma, human hepatocellular carcinoma and other diseases. Shcbp1 may play an important role in tumorigenesis and progression. Accordingly, recent studies are reviewed herein to discuss and interpret the role of Shcbp1 in normal cell proliferation and differentiation, tumorigenesis and progression, as well as its interactions with proteins.

TRIM14 Promotes Noncanonical NF-κB Activation by Modulating p100/p52 Stability via Selective Autophagy

The noncanonical NF-κB signaling pathway plays a critical role in a variety of biological functions including chronic inflammation and tumorigenesis. Activation of noncanonical NF-κB signaling largely relies on the abundance as well as the processing of the NF-κB family member p100/p52. Here, TRIM14 is identified as a novel positive regulator of the noncanonical NF-κB signaling pathway. TRIM14 promotes noncanonical NF-κB activation by targeting p100/p52 in vitro and in vivo. Furthermore, a mechanistic study shows that TRIM14 recruits deubiquitinase USP14 to cleave the K63-linked ubiquitin chains of p100/p52 at multiple sites, thereby preventing p100/p52 from cargo receptor p62-mediated autophagic degradation. TRIM14 deficiency in mice significantly impairs noncanonical NF-κB-mediated inflammatory responses as well as acute colitis and colitis-associated colon cancer development. Taken together, these findings establish the TRIM14-USP14 axis as a crucial checkpoint that controls noncanonical NF-κB signaling and highlight the crosstalk between autophagy and innate immunity.

NF-κB2 signalling in enteroids modulates enterocyte responses to secreted factors from bone marrow-derived dendritic cells

Alternative pathway NF-κB signalling regulates susceptibility towards developing inflammatory bowel disease (IBD), colitis-associated cancer and sepsis-associated intestinal epithelial cell apoptosis and shedding. However, the cell populations responsible for the perturbed alternative pathway NF-κB signalling in intestinal mucosal pathology remain unclear. In order to investigate the contribution of the epithelial compartment, we have tested whether NF-κB2 regulated transcription in intestinal epithelial cells controls the intestinal epithelial response to cytokines that are known to disrupt intestinal barrier permeability. Enteroids were generated from the proximal, middle and distal regions of small intestine (SI) from C57BL/6J wild-type mice and displayed region-specific morphology that was maintained during sub-culture. Enteroids treated with 100 ng/mL TNF were compared with corresponding regions of SI from C57BL/6J mice treated systemically with 0.33 mg/kg TNF for 1.5 h. TNF-induced apoptosis in all regions of the intestine in vitro and in vivo but resulted in Paneth cell degranulation only in proximal tissue-derived SI and enteroids. TNF also resulted in increased enteroid sphericity (quantified as circularity from two-dimensional bright field images). This response was dose and time-dependent and correlated with active caspase-3 immunopositivity. Proximal tissue-derived enteroids generated from Nfκb2^−/− mice showed a significantly blunted circularity response following the addition of TNF, IFNγ, lipopolysaccharide (LPS) activated C57BL/6J-derived bone marrow-derived dendritic cells (BMDC) and secreted factors from LPS-activated BMDCs. However, Nfκb1^−/− mouse-derived enteroids showed no significant changes in response to these stimuli. In conclusion, the selection of SI region is important when designing enteroid studies as region-specific identity and response to stimuli such as TNF are maintained in culture. Intestinal epithelial cells are at least partially responsible for regulating their own fate by modulating NF-κB2 signalling in response to stimuli known to be involved in multiple intestinal and systemic diseases. Future studies are warranted to investigate the therapeutic potential of intestinal epithelial NF-κB2 inhibition.

IL-6-driven FasL promotes NF-κBp65/PUMA-mediated apoptosis in portal hypertensive gastropathy

Mucosal epithelial apoptosis with non-specific inflammation is an essential pathological characteristic in portal hypertensive gastropathy (PHG). However, whether a coordinated crosstalk between myeloid cells and epithelial cells involved in PHG remains unclear. IL-6, which is induced in the mucosa of PHG patients and mice, promotes FasL production via enhancing NF-κBp65 activation in myeloid cells, while blockage of IL-6 signaling by Tocilizumab or deletion of NF-κBp65 in myeloid cells attenuates the inflammatory response and Fas/FasL-mediated epithelial apoptosis in PHG. IL-6-driven FasL from myeloid cells combines with epithelial Fas receptor to encourage NF-κBp65/PUMA-mediated epithelial apoptosis in PHG, and inhibition of NF-κBp65 or knockout of PUMA alleviates Fas/FasL-mediated epithelial apoptosis in PHG. These results indicate that IL-6 drives FasL generation via NF-κBp65 in myeloid cells to promote Fas/NF-κBp65/PUMA-mediated epithelial apoptosis in PHG, and this coordinated crosstalk between myeloid cells and epithelial cells may provide a potential therapeutic target for PHG.

Macrophage-Specific NF-κB Activation Dynamics Can Segregate Inflammatory Bowel Disease Patients

The heterogeneous nature of inflammatory bowel disease (IBD) presents challenges, particularly when choosing therapy. Activation of the NF-κB transcription factor is a highly regulated, dynamic event in IBD pathogenesis. Using a lentivirus approach, NF-κB-regulated luciferase was expressed in patient macrophages, isolated from frozen peripheral blood mononuclear cell samples. Following activation, samples could be segregated into three clusters based on the NF-κB-regulated luciferase response. The ulcerative colitis (UC) samples appeared only in the hypo-responsive Cluster 1, and in Cluster 2. Conversely, Crohn's disease (CD) patients appeared in all Clusters with their percentage being higher in the hyper-responsive Cluster 3. A positive correlation was seen between NF-κB-induced luciferase activity and the concentrations of cytokines released into medium from stimulated macrophages, but not with serum or biopsy cytokine levels. Confocal imaging of lentivirally-expressed p65 activation revealed that a higher proportion of macrophages from CD patients responded to endotoxin lipid A compared to controls. In contrast, cells from UC patients exhibited a shorter duration of NF-κB p65 subunit nuclear localization compared to healthy controls, and CD donors. Analysis of macrophage cytokine responses and patient metadata revealed a strong correlation between CD patients who smoked and hyper-activation of p65. These in vitro dynamic assays of NF-κB activation in blood-derived macrophages have the potential to segregate IBD patients into groups with different phenotypes and may therefore help determine response to therapy.

Reactive Oxygen Species Are Involved in the Development of Gastric Cancer and Gastric Cancer-Related Depression through ABL1-Mediated Inflammation Signaling Pathway

Background

The mechanisms of crosstalk between depression and gastric cancer (GC) remain ill defined. Given that reactive oxygen species (ROS) is involved in the pathophysiology of both GC and depression, we try to explore the activities of ROS in the development of GC and GC-related depression.

Methods

110 patients with newly diagnosed GC were recruited in our study. The clinical characteristics of these patients were recorded. Inflammation and oxidative stress markers were detected by ELISA. The depression status of patients with GC was assessed during follow-up. The association between ROS, ABL1, and inflammation factors was evaluated in H₂O₂-treated GC cell lines and The Cancer Genome Atlas (TCGA) database. The effect of ABL1 on inflammation was detected with Imatinib/Nilotinib-treated GC cell lines. A chronic mild stress- (CMS-) induced patient-derived xenograft (PDX) mice model was established to assess the crosstalk between depression and GC.

Results

Depression was correlated with poor prognosis of patients with GC. GC patients with depression were under a high level of oxidative status as well as dysregulated inflammation. In the CMS-induced GC PDX mice model, CMS could facilitate the development of GC. Additionally, tumor bearing could induce depressive-like behaviors of mice. With the treatment of ROS, the activities of ABL1 and inflammatory signaling were enhanced both in vitro and in vivo, and blocking the activities of ABL1 inhibited inflammatory signaling.

Conclusions

ROS-activated ABL1 mediates inflammation through regulating NF-κB1 and STAT3, which subsequently leads to the development of GC and GC-related depression.

Intersection of the p63 and NF-κB pathways in epithelial homeostasis and disease

Overexpression of ΔNp63α, a member of the p53/p63/p73 family of transcription factors, is a molecular attribute of human squamous cancers of the head and neck, lung and skin. The TP63 gene plays important roles in epidermal morphogenesis and homeostasis, regulating diverse biological processes including epidermal fate decisions and keratinocyte proliferation and survival. When overexpressed experimentally in primary mouse keratinocytes, ΔNp63α maintains a basal cell phenotype including the loss of normal calcium-mediated growth arrest, at least in part through the activation and enhanced nuclear accumulation of the c-rel subunit of NF-κB (Nuclear Factor-kappa B). Initially identified for its role in the immune system and hematopoietic cancers, c-Rel has increasingly been associated with solid tumors and other pathologies. ΔNp63α and c-Rel have been shown to be associated in the nuclei of ΔNp63α overexpressing human squamous carcinoma cells. Together, these transcription factors cooperate in the transcription of genes regulating intrinsic keratinocyte functions, as well as the elaboration of factors that influence the tumor microenvironment (TME). This review provides an overview of the roles of ΔNp63α and c-Rel in normal epidermal homeostasis and elaborates on how these pathways may intersect in pathological conditions such as cancer and the associated TME.

Analysis of Genes Involved in Ulcerative Colitis Activity and Tumorigenesis Through Systematic Mining of Gene Co-expression Networks

Ulcerative colitis (UC) is an idiopathic, chronic inflammatory disorder of the colon, characterized by continuous mucosal inflammation. Recently, some studies have considered it as part of an inflammatory bowel disease-based global network. Herein, with the aim of identifying the underlying potential genetic mechanisms involved in the development of UC, multiple algorithms for weighted correlation network analysis (WGCNA), principal component analysis (PCA), and linear models for microarray data algorithm (LIMMA) were used to identify the hub genes. The map of platelet activation, ligand-receptor interaction, calcium signaling pathway, and cAMP signaling pathway showed significant links with UC development, and the hub genes CCR7, CXCL10, CXCL9, IDO1, MMP9, and VCAM1, which are associated with immune dysregulation and tumorigenesis in biological function, were found by multiple powerful bioinformatics methods. Analysis of The Cancer Genome Atlas (TCGA) also showed that the low expression of CCR7, CXCL10, CXCL9, and MMP9 may be correlated with a poor prognosis of overall survival (OS) in colorectal cancer (CRC) patients (all p < 0.05), while no significance detected in both of IDO1 and VCAM1. In addition, low expression of CCR7, CXCL10, CXCL9, MMP9, and IDO1 may be associated with a poor prognosis in recurrence free survival (RFS) time (all p < 0.05), but no significant difference was identified in VCAM1. Moreover, the NFKB1, FLI1, and STAT1 with the highest enrichment score were detected as the master regulators of hub genes. In summary, these results indicated the central role of the hub genes of CCR7, CXCL10, CXCL9, IDO1, VCAM1, and MMP9, in response to UC progression, as well as the development of UC to CRC, thus shedding light on the molecular mechanisms involved and assisting with drug target validation.

Intestinal non-canonical NFκB signaling shapes the local and systemic immune response

Microfold cells (M-cells) are specialized cells of the intestine that sample luminal microbiota and dietary antigens to educate the immune cells of the intestinal lymphoid follicles. The function of M-cells in systemic inflammatory responses are still unclear. Here we show that epithelial non-canonical NFkB signaling mediated by NFkB-inducing kinase (NIK) is highly active in intestinal lymphoid follicles, and is required for M-cell maintenance. Intestinal NIK signaling modulates M-cell differentiation and elicits both local and systemic IL-17A and IgA production. Importantly, intestinal NIK signaling is active in mouse models of colitis and patients with inflammatory bowel diseases; meanwhile, constitutive NIK signaling increases the susceptibility to inflammatory injury by inducing ectopic M-cell differentiation and a chronic increase of IL-17A. Our work thus defines an important function of non-canonical NFkB and M-cells in immune homeostasis, inflammation and polymicrobial sepsis.

Combining multi-dimensional data to identify a key signature (gene and miRNA) of cisplatin-resistant gastric cancer

Gastric cancer (GC) is one of the most lethal malignant tumors; the resistance of this type of tumor is the main source of GC treatment failure. In this study, we used bioinformatics analysis to verify differences in resistant GCs and identify an effective method for reversing drug resistance in GC. Microarray data [gene and microRNA (miRNA)] were analyzed using GEO2R software, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were applied to further enrich the genetic data. miRNA-gene interactions were determined using Cytoscape (v.3.5.1). Online software was used to analyze protein interactions and predict network structure. The Cancer Genome Atlas (TCGA) database was used to verify the expression levels of genes in GC resistance. miR-604 expression levels were verified by real-time PCR in GC cell lines. We screened 3981 GC resistance-associated genes and 244 miRNAs using bioinformatics methods. Six hub genes were identified and verified in the TCGA database, including five up-regulated genes, POLR2L, POLR2C, POLR2F, APRT, and LMAN2, and a down-regulated gene, NFKB2. The up-regulated genes POLR2L, POLR2C, APRT, and LMAN2 interact with miR-604; therefore, we focused on miR-604, which has low expression in drug-resistant GC. The results of this study indicate that through bioinformatics technologies, we have determined the hub genes and hub miRNAs related to drug resistance in GC. Among them, miR-604 could become a new indicator in the diagnosis of drug-resistant GC and may be used to investigate the pathogenesis of resistance in GC.

The non-canonical NF-κB pathway in immunity and inflammation

The nuclear factor-κB (NF-κB) family of transcription factors is activated by canonical and non-canonical signalling pathways, which differ in both signalling components and biological functions. Recent studies have revealed important roles for the non-canonical NF-κB pathway in regulating different aspects of immune functions. Defects in non-canonical NF-κB signalling are associated with severe immune deficiencies, whereas dysregulated activation of this pathway contributes to the pathogenesis of various autoimmune and inflammatory diseases. Here we review the signalling mechanisms and the biological function of the non-canonical NF-κB pathway. We also discuss recent progress in elucidating the molecular mechanisms regulating non-canonical NF-κB pathway activation, which may provide new opportunities for therapeutic strategies.

Mice lacking NF-κB1 exhibit marked DNA damage responses and more severe gastric pathology in response to intraperitoneal tamoxifen administration

Tamoxifen (TAM) has recently been shown to cause acute gastric atrophy and metaplasia in mice. We have previously demonstrated that the outcome of Helicobacter felis infection, which induces similar gastric lesions in mice, is altered by deletion of specific NF-κB subunits. Nfkb1^-/- mice developed more severe gastric atrophy than wild-type (WT) mice 6 weeks after H. felis infection. In contrast, Nfkb2^-/- mice were protected from this pathology. We therefore hypothesized that gastric lesions induced by TAM may be similarly regulated by signaling via NF-κB subunits. Groups of five female C57BL/6 (WT), Nfkb1^-/-, Nfkb2^-/- and c-Rel^-/- mice were administered 150 mg/kg TAM by IP injection. Seventy-two hours later, gastric corpus tissues were taken for quantitative histological assessment. In addition, groups of six female WT and Nfkb1^-/- mice were exposed to 12 Gy γ-irradiation. Gastric epithelial apoptosis was quantified 6 and 48 h after irradiation. TAM induced gastric epithelial lesions in all strains of mice, but this was more severe in Nfkb1^-/- mice than in WT mice. Nfkb1^-/- mice exhibited more severe parietal cell loss than WT mice, had increased gastric epithelial expression of Ki67 and had an exaggerated gastric epithelial DNA damage response as quantified by γH2AX. To investigate whether the difference in gastric epithelial DNA damage response of Nfkb1^-/- mice was unique to TAM-induced DNA damage or a generic consequence of DNA damage, we also assessed gastric epithelial apoptosis following γ-irradiation. Six hours after γ-irradiation, gastric epithelial apoptosis was increased in the gastric corpus and antrum of Nfkb1^-/- mice. NF-κB1-mediated signaling regulates the development of gastric mucosal pathology following TAM administration. This is associated with an exaggerated gastric epithelial DNA damage response. This aberrant response appears to reflect a more generic sensitization of the gastric mucosa of Nfkb1^-/- mice to DNA damage.

The non-canonical NF-κB pathway in immunity and inflammation

The nuclear factor-κB (NF-κB) family of transcription factors is activated by canonical and non-canonical signalling pathways, which differ in both signalling components and biological functions. Recent studies have revealed important roles for the non-canonical NF-κB pathway in regulating different aspects of immune functions. Defects in non-canonical NF-κB signalling are associated with severe immune deficiencies, whereas dysregulated activation of this pathway contributes to the pathogenesis of various autoimmune and inflammatory diseases. Here we review the signalling mechanisms and the biological function of the non-canonical NF-κB pathway. We also discuss recent progress in elucidating the molecular mechanisms regulating non-canonical NF-κB pathway activation, which may provide new opportunities for therapeutic strategies.

Insights into the Link Between Obesity and Cancer

PURPOSE OF REVIEW

Adipocytes have adapted to store energy in the form of lipid and also secrete circulating factors called adipokines that signal to other tissues to coordinate energy homeostasis. These functions are disrupted in the setting of obesity, promoting the development of diseases such as diabetes, cardiovascular disease, and cancer.

RECENT FINDINGS

Obesity is linked to an increased risk of many types of cancer and increased cancer-related mortality. The basis for the striking association between obesity and cancer is not well understood. Here, we review the cellular and molecular pathways that appear to be involved in obesity-driven cancer. We also describe possible therapeutic considerations and highlight important unanswered questions in the field.

Emerging Roles for Noncanonical NF-κB Signaling in the Modulation of Inflammatory Bowel Disease Pathobiology

Crohn's disease and ulcerative colitis are common and debilitating manifestations of inflammatory bowel disease (IBD). IBD is characterized by a radical imbalance in the activation of proinflammatory and anti-inflammatory signaling pathways in the gut. These pathways are controlled by NF-κB, which is a master regulator of gene transcription. In IBD patients, NF-κB signaling is often dysregulated resulting in overzealous inflammation. NF-κB activation occurs through 2 distinct pathways, defined as either canonical or noncanonical. Canonical NF-κB pathway activation is well studied in IBD and is associated with the rapid, acute production of diverse proinflammatory mediators, such as COX-2, IL-1β, and IL-6. In contrast to the canonical pathway, the noncanonical or "alternative" NF-κB signaling cascade is tightly regulated and is responsible for the production of highly specific chemokines that tend to be associated with less acute, chronic inflammation. There is a relative paucity of literature regarding all aspects of noncanonical NF-ĸB signaling. However, it is clear that this alternative signaling pathway plays a considerable role in maintaining immune system homeostasis and likely contributes significantly to the chronic inflammation underlying IBD. Noncanonical NF-κB signaling may represent a promising new direction in the search for therapeutic targets and biomarkers associated with IBD. However, significant mechanistic insight is still required to translate the current basic science findings into effective therapeutic strategies.

Importance of the alternative NF-κB activation pathway in inflammation-associated gastrointestinal carcinogenesis

Chronic inflammation is a common factor in the development of many gastrointestinal malignancies. Examples include inflammatory bowel disease predisposing to colorectal cancer, Barrett's esophagus as a precursor of esophageal adenocarcinoma, and Helicobacter pylori-induced gastric cancer. The classical activation pathway of NF-κB signaling has been identified as regulating several sporadic and inflammation-associated gastrointestinal tract malignancies. Emerging evidence suggests that the alternative NF-κB signaling pathway also exerts a distinct influence on these processes. This review brings together current knowledge of the role of the alternative NF-κB signaling pathway in the gastrointestinal tract, with a particular emphasis on inflammation-associated cancer development.

c-Rel and its many roles in cancer: an old story with new twists

When the genes encoding NF-κB subunits were first isolated, their homology to the previously identified c-Rel proto-oncogene and its viral homologue v-Rel was clear. This provided the first indication that these transcription factors also had a role in cancer. Because of its homology to v-Rel, which transforms chicken B cells together with the important role c-Rel can have as a regulator of B- and T-cell proliferation, most attention has focussed on its role in B-cell lymphomas, where the REL gene is frequently amplified. However, a growing number of reports now indicate that c-Rel has important functions in many solid tumours, although studies in mice suggest it may not always function as an oncogene. Moreover, c-Rel is a critical regulator of fibrosis, which provides an environment for tumour development in many settings. Overall, c-Rel is emerging as a complex regulator of tumorigenesis, and there is still much to learn about its functions in human malignancies and the response to cancer therapies.

The B-cell tumor promoter Bcl-3 suppresses inflammation-associated colon tumorigenesis in epithelial cells

Bcl-3 is an atypical member of the IκB family. It associates with p50/NF-κB1 and p52/NF-κB2 homodimers in nuclei where it modulates transcription in a context-dependent manner. A subset of B cell tumors exhibits recurrent translocations of Bcl-3, resulting in overexpression. Elevated expression without translocations is also observed in various B cell lymphomas and even some solid tumors. Here we investigated the role of Bcl-3 in AOM/DSS-induced colon tumors, a mouse model for colitis-associated colorectal cancers in humans. Contrary to expectations, Bcl-3 suppressed colorectal tumor formation: Bcl-3-deficient mice were relatively protected from DSS-induced epithelial damage and developed more polyps after AOM/DSS treatment, though polyp size was unaffected. DSS-challenged mutant mice exhibited increased recruitment of myeloid-derived suppressor cells (MDSCs), consistent with protection of the epithelium. Loss of Bcl-3 in intestinal epithelial cells was sufficient to increase tumorigenesis. The added tumor burden in mutant mice was dependent on TNFα, a tumorigenic, NF-κB-mediated signaling pathway that was dampened by Bcl-3. These findings reveal a tumor-suppressive role for Bcl-3 in this inflammation-associated cancer model. Bcl-3 thus functions as a tumor promoter or suppressor, depending on the cellular and environmental context.