Bcl3 Phosphorylation by Akt, Erk2, and IKK Is Required for Its Transcriptional Activity.

Unlike prototypical IκB proteins, which are inhibitors of NF-κB RelA, cRel, and RelB dimers, the atypical IκB protein Bcl3 is primarily a transcriptional coregulator of p52 and p50 homodimers. Bcl3 exists as phospho-protein in many cancer cells. Unphosphorylated Bcl3 acts as a classical IκB-like inhibitor and removes p50 and p52 from bound DNA. Neither the phosphorylation site(s) nor the kinase(s) phosphorylating Bcl3 is known. Here we show that Akt, Erk2, and IKK1/2 phosphorylate Bcl3. Phosphorylation of Ser33 by Akt induces switching of K48 ubiquitination to K63 ubiquitination and thus promotes nuclear localization and stabilization of Bcl3. Phosphorylation by Erk2 and IKK1/2 of Ser114 and Ser446 converts Bcl3 into a transcriptional coregulator by facilitating its recruitment to DNA. Cells expressing the S114A/S446A mutant have cellular proliferation and migration defects. This work links Akt and MAPK pathways to NF-κB through Bcl3 and provides mechanistic insight into how Bcl3 functions as an oncoprotein through collaboration with IKK1/2, Akt, and Erk2.

Multifaceted roles for BCL3 in cancer: a proto-oncogene comes of age.

In the early 1990's a group of unrelated genes were identified from the sites of recurring translocations in B-cell lymphomas. Despite sharing the nomenclature 'Bcl', and an association with blood-borne cancer, these genes have unrelated functions. Of these genes, BCL2 is best known as a key cancer target involved in the regulation of caspases and other cell viability mechanisms. BCL3 on the other hand was originally identified as a non-canonical regulator of NF-kB transcription factor pathways - a signaling mechanism associated with important cell outcomes including many of the hallmarks of cancer. Most of the early investigations into BCL3 function have since focused on its role in NF-kB mediated cell proliferation, inflammation/immunity and cancer. However, recent evidence is coming to light that this protein directly interacts with and modulates a number of other signaling pathways including DNA damage repair, WNT/ß-catenin, AKT, TGFß/SMAD3 and STAT3 - all of which have key roles in cancer development, metastatic progression and treatment of solid tumours. Here we review the direct evidence demonstrating BCL3's central role in a transcriptional network of signaling pathways that modulate cancer biology and treatment response in a range of solid tumour types and propose common mechanisms of action of BCL3 which may be exploited in the future to target its oncogenic effects for patient benefit.

Loss of Bcl-3 regulates macrophage polarization by promoting macrophage glycolysis.

M1/M2 macrophage polarization plays an important role in regulating the balance of the microenvironment within tissues. Moreover, macrophage polarization involves the reprogramming of metabolism, such as glucose and lipid metabolism. Transcriptional coactivator B-cell lymphoma-3 (Bcl-3) is an atypical member of the IκB family that controls inflammatory factor levels in macrophages by regulating nuclear factor kappa B pathway activation. However, the relationship between Bcl-3 and macrophage polarization and metabolism remains unclear. In this study, we show that the knockdown of Bcl-3 in macrophages can regulate glycolysis-related gene expression by promoting the activation of the nuclear factor kappa B pathway. Furthermore, the loss of Bcl-3 was able to promote the interferon gamma/lipopolysaccharide-induced M1 macrophage polarization by accelerating glycolysis. Taken together, these results suggest that Bcl-3 may be a candidate gene for regulating M1 polarization in macrophages.

Discovery of a small molecule that inhibits Bcl-3-mediated cyclin D1 expression in melanoma cells.

Molecular targeted therapy using a drug that suppresses the growth and spread of cancer cells via inhibition of a specific protein is a foundation of precision medicine and treatment. High expression of the proto-oncogene Bcl-3 promotes the proliferation and metastasis of cancer cells originating from tissues such as the colon, prostate, breast, and skin. The development of novel drugs targeting Bcl-3 alone or in combination with other therapies can cure these patients or prolong their survival. As a proof of concept, in the present study, we focused on metastatic melanoma as a model system. High-throughput screening and in vitro experiments identified BCL3ANT as a lead molecule that could interfere with Bcl-3-mediated cyclin D1 expression and cell proliferation and migration in melanoma. In experimental animal models of melanoma, it was demonstrated that the use of a Bcl-3 inhibitor can influence the survival of melanoma cells. Since there are no other inhibitors against Bcl-3 in the clinical pipeline for cancer treatment, this presents a unique opportunity to develop a highly specific drug against malignant melanoma to meet an urgent clinical need.

Bcl-3 regulates T cell function through energy metabolism.

BACKGROUND: Bcl-3 is a member of the IκB protein family and an essential modulator of NF-κB activity. It is well established that Bcl-3 is critical for the normal development, survival and differentiation of adaptive immune cells, especially T cells. However, the regulation of immune cell function by Bcl-3 through metabolic pathways has rarely been studied. RESULTS: In this study, we explored the role of Bcl-3 in the metabolism and function of T cells via the mTOR pathway. We verified that the proliferation of Bcl-3-deficient Jurkat T cells was inhibited, but their activation was promoted, and Bcl-3 depletion regulated cellular energy metabolism by reducing intracellular ATP and ROS production levels and mitochondrial membrane potential. Bcl-3 also regulates cellular energy metabolism in naive CD4+ T cells. In addition, the knockout of Bcl-3 altered the expression of mTOR, Akt, and Raptor, which are metabolism-related genes, in Jurkat cells. CONCLUSIONS: This finding indicates that Bcl-3 may mediate the energy metabolism of T cells through the mTOR pathway, thereby affecting their function. Overall, we provide novel insights into the regulatory role of Bcl-3 in T-cell energy metabolism for the prevention and treatment of immune diseases.

Multiple roles for Bcl-3 in mammary gland branching, stromal collagen invasion, involution and tumor pathology.

BACKGROUND: The Bcl-3 protein is an atypical member of the inhibitor of -κB family that has dual roles as a transcriptional repressor and a coactivator for dimers of NF-κB p50 and p52. Bcl-3 is expressed in mammary adenocarcinomas and can promote tumorigenesis and survival signaling and has a key role in tumor metastasis. In this study, we have investigated the role of Bcl-3 in the normal mammary gland and impact on tumor pathology. METHODS: We utilized bcl-3-/- mice to study mammary gland structure in virgins and during gestation, lactation and early involution. Expression of involution-associated genes and proteins and putative Bcl-3 target genes was examined by qRT-PCR and immunoblot analysis. Cell autonomous branching morphogenesis and collagen I invasion properties of bcl-3-/- organoids were tested in 3D hydrogel cultures. The role of Bcl-3 in tumorigenesis and tumor pathology was also assessed using a stochastic carcinogen-induced mammary tumor model. RESULTS: Bcl-3-/- mammary glands demonstrated reduced branching complexity in virgin and pregnant mice. This defect was recapitulated in vitro where significant defects in bud formation were observed in bcl-3-/- mammary organoid cultures. Bcl-3-/- organoids showed a striking defect in protrusive collective fibrillary collagen I invasion associated with reduced expression of Fzd1 and Twist2. Virgin and pregnant bcl-3-/- glands showed increased apoptosis and rapid increases in lysosomal cell death and apoptosis after forced weaning compared to WT mice. Bcl-2 and Id3 are strongly induced in WT but not bcl-3-/- glands in early involution. Tumors in WT mice were predominately adenocarcinomas with NF-κB activation, while bcl-3-/- lesions were largely squamous lacking NF-κB and with low Bcl-2 expression. CONCLUSIONS: Collectively, our results demonstrate that Bcl-3 has a key function in mammary gland branching morphogenesis, in part by regulation of genes involved in extracellular matrix invasion. Markedly reduced levels of pro-survival proteins expression in bcl-3 null compared to WT glands 24 h post-weaning indicate that Bcl-3 has a role in moderating the rate of early phase involution. Lastly, a reduced incidence of bcl-3-/- mammary adenocarcinomas versus squamous lesions indicates that Bcl-3 supports the progression of epithelial but not metaplastic cancers.

Bcl3 Couples Cancer Stem Cell Enrichment With Pancreatic Cancer Molecular Subtypes.

BACKGROUND & AIMS: The existence of different subtypes of pancreatic ductal adenocarcinoma (PDAC) and their correlation with patient outcome have shifted the emphasis on patient classification for better decision-making algorithms and personalized therapy. The contribution of mechanisms regulating the cancer stem cell (CSC) population in different subtypes remains unknown. METHODS: Using RNA-seq, we identified B-cell CLL/lymphoma 3 (BCL3), an atypical nf-κb signaling member, as differing in pancreatic CSCs. To determine the biological consequences of BCL3 silencing in vivo and in vitro, we generated bcl3-deficient preclinical mouse models as well as murine cell lines and correlated our findings with human cell lines, PDX models, and 2 independent patient cohorts. We assessed the correlation of bcl3 expression pattern with clinical parameters and subtypes. RESULTS: Bcl3 was significantly down-regulated in human CSCs. Recapitulating this phenotype in preclinical mouse models of PDAC via BCL3 genetic knockout enhanced tumor burden, metastasis, epithelial to mesenchymal transition, and reduced overall survival. Fluorescence-activated cell sorting analyses, together with oxygen consumption, sphere formation, and tumorigenicity assays, all indicated that BCL3 loss resulted in CSC compartment expansion promoting cellular dedifferentiation. Overexpression of BCL3 in human PDXs diminished tumor growth by significantly reducing the CSC population and promoting differentiation. Human PDACs with low BCL3 expression correlated with increased metastasis, and BCL3-negative tumors correlated with lower survival and nonclassical subtypes. CONCLUSIONS: We demonstrate that bcl3 impacts pancreatic carcinogenesis by restraining CSC expansion and by curtailing an aggressive and metastatic tumor burden in PDAC across species. Levels of BCL3 expression are a useful stratification marker for predicting subtype characterization in PDAC, thereby allowing for personalized therapeutic approaches.

Bcl-3 inhibits lupus-like phenotypes in BL6/lpr mice.

Bcl-3 is an atypical member of the IκB family that modulates NF-κB activity in nuclei. lpr mice carry the lpr mutation in Fas, resulting in functional loss of this death receptor; they serve as models for lupus erythematosus and autoimmune lymphoproliferation syndrome (ALPS). To explore the biologic roles of Bcl-3 in this disease model, we generated BL6/lpr mice lacking Bcl-3. Unlike lpr mice on an MRL background, BL6/lpr mice present with very mild lupus- or ALPS-like phenotypes. Bcl-3 KO BL6/lpr mice, however, developed severe splenomegaly, dramatically increased numbers of double negative T cells - a hallmark of human lupus, ALPS, and MRL/lpr mice - and exhibited inflammation in multiple organs, despite low levels of autoantibodies, similar to those in BL6/lpr mice. Loss of Bcl-3 specifically in T cells exacerbated select lupus-like phenotypes, specifically organ infiltration. Mechanistically, elevated levels of Tnfα in Bcl-3 KO BL6/lpr mice may promote lupus-like phenotypes, since loss of Tnfα in these mice reversed the pathology due to loss of Bcl-3. Contrary to the inhibitory functions of Bcl-3 revealed here, this regulator has also been shown to promote inflammation in different settings. Our findings highlight the profound, yet highly context-dependent roles of Bcl-3 in the development of inflammation-associated pathology.

Knockdown of Bcl-3 alleviates psoriasis and dyslipidemia comorbidity by regulating Akt pathway.

BACKGROUND: Psoriasis is considered as an inflammatory skin disease accompanied by dyslipidemia comorbidity. B-cell leukemia-3 (Bcl-3) belongs to IκB (inhibitor of nuclear factor kappa B [NF-κB]) family, and regulates inflammatory response through associating with NF-κB. The role of Bcl-3 in psoriasis was investigated in this study. METHODS: Apolipoprotein E (ApoE)-deficient mice were treated with imiquimod to induce psoriasis and dyslipidemia. Mice were injected intradermally in the back with lentiviral particles encoding Bcl-3 small hairpin RNA (shRNA). Hematoxylin and eosin were used to detect pathological characteristics. The blood lipid levels were determined by automatic biochemical analyzer, and inflammation was assessed by enzyme-linked-immunosorbent serologic assay and real-time quantitative reverse transcription polymerase chain reaction. RESULTS: Bcl-3 was elevated in imiquimod-induced ApoE-deficient mice. Injection with lentiviral particles encoding Bcl-3 shRNA reduced Psoriasis area and severity index (PASI) score in ApoE-deficient psoriatic mice. Knockdown of Bcl-3 also ameliorated imiquimod-induced psoriasiform skin lesions in ApoE-deficient mice. Moreover, loss of Bcl-3 enhanced expression of loricrin, an epidermal barrier protein, reduced expression of proliferating cell nuclear antigen (PCNA) and lectin-like oxidized LDL (oxLDL) receptor-1 (LOX-1) in imiquimod-induced ApoE-deficient mice. The enhanced levels of blood lipid in ApoE-deficient mice were attenuated by silencing of Bcl-3 with increase of high-density lipoprotein, and reduction of total cholesterol, triglycerides, and low-density lipoprotein cholesterol. Knockdown of Bcl-3 attenuated imiquimod-induced decrease of transforming growth factor beta (TGF-ß), and increase of Interleukin (IL)-17A, IL-23, IL-6, and tumor necrosis factor-α (TNF-α) in ApoE-deficient mice. Protein expression of phospho-Akt (p-Akt) and p-GSK3ß in ApoE-deficient psoriatic mice was decreased by silencing of Bcl-3. CONCLUSION: Loss of Bcl-3 exerted anti-inflammatory effect on psoriasis and dyslipidemia comorbidity through inactivation of Akt/GSK3ß pathway.

PCAT1 induced by transcription factor YY1 promotes cholangiocarcinoma proliferation, migration and invasion by sponging miR-216a-3p to up-regulate oncogene BCL3.

This study was designed to illustrate the function and role of PCAT1 in CCA. The relative expression was confirmed by RT-qPCR and western blot. The biological function of PCAT1 was evaluated by CCK8, EdU, colony formation, wound healing, transwell, and subcutaneous tumor formation assays. Protein levels of EMT markers were measured by western blot. The binding relationship was predicted by JASPAR and starBase. The binding of YY1 to PCAT1 promoter was assessed by ChIP and luciferase reporter. The binding capacity between miR-216a-3p and PCAT1 as well as BCL3 was assessed by luciferase reporter and AGO2-RIP assays. In this study, we found that PCAT1 was up-regulated in CCA tissues and cells, and the PCAT1 overexpression was associated with poor prognosis. Moreover, PCAT1 was assessed as an independent risk factor of prognosis for CCA patients. Amplified PCAT1 was found to promote tumor proliferation, migration, invasion and EMT process, whereas PCAT1 knockdown inhibited these malignant phenotypes. Mechanistically, PCAT1 was predominantly localized in the cytoplasm and competitively bound miR-216a-3p to increase BCL3 expression. In addition, PCAT1 was activated by transcription factor YY1. This study revealed that PCAT1 acted as an oncogene in CCA, and the YY1/PCAT1/miR-216a-3p/BCL3 axis exhibited critical functions in CCA progression.

Expression of DOCK10.1 protein revealed with a specific antiserum: insights into regulation of first exon isoforms of DOCK10.

DOCK10, a guanine-nucleotide exchange factor (GEF) for Rho GTPases, represents the example of a gene that gives rise to alternative first exon mRNA isoforms, named DOCK10.1 and DOCK10.2. Expression of human DOCK10.2 protein in cell lines, and its induction by interleukin-4 (IL-4) in normal B lymphocytes and chronic lymphocytic leukemia (CLL) cells, were previously demonstrated using an antiserum raised against a peptide encoded by sequences from exon 1.2. Here, expression of human DOCK10.1 protein was demonstrated using an antiserum raised against a peptide encoded by sequences from exon 1.1. Specificity of the DOCK10.1 and DOCK10.2 antisera for their respective isoforms was demonstrated using transfected human 293 T cells. Their specificity for endogenous DOCK10 was strongly suggested by the high significance of the correlations between the levels of their expected signals at the molecular size of 250 kDa and the levels of DOCK10.1 and DOCK10.2 mRNAs, respectively, in human hematopoietic cell lines. Specificity of the DOCK10.1 antiserum for DOCK10 was also demostrated in mouse using the DOCK10 knockout model. The DOCK10.1 protein was induced by IL-4 in CLL cells, which demonstrates that the mechanism by which IL-4 regulates DOCK10 is not isoform-specific. Last, to get insights into differential regulation of the DOCK10 isoforms, their protein levels in cell lines were compared with their gene expression profiles retrieved from the Cancer Cell Line Encyclopedia (CCLE), leading to the identification of BCL3 and KLF12 as potential transcriptional regulators of DOCK10.1 and DOCK10.2, respectively.

BCL-3 and ß-catenin signaling and tumor staging in colorectal cancer.

Colorectal cancer (CBC) is the third most common cancer in men and the second most common cancer in women in the world, as well as the second leading cause of death among the world's cancers. In this study, to identify the genes involved in the CRC clinical outcomes, the expression of B cell leukemia/lymphoma 3 (BCL-3) gene in patients with colorectal cancer was investigated along with serum level of ß-catenin. In this study, samples of 23 patients with colorectal cancer were prepared. mRNA was extracted and then cDNA was prepared for evaluation of PCR. Then, with specific primers for the BCL3, a semi-quantitative RT-PCR test was performed. The enzyme-linked immunosorbent assay (ELISA) was used to assess the serum level of ß-catenin. In this study, 23 men with an average age of years were included. BCL-3 expression in tumor tissue was significantly higher than its level in healthy tissue (P=0.021). BCL-3 expression at stage 0 of the tumor was significantly lower than at all other stages (P<0.05), and the comparison between the rest of the CRC stages was not significant (P>0.05). The median of serum ß-catenin levels in the patients was 32.83 (22.45, 46.09). There was no significant difference in the amount of serum ß-catenin between all 5 stages of the disease and in terms of lymph node metastasis. There were no relationships between age, BMI, smoking history, familial CRC history, and BCL-3 or ß-catenin serum levels (P>0.05). In this study, the expression of the BCL-3 gene in tumor specimens was high. It can be said that the BCL-3 gene can act as one of the genes involved in colorectal cancer, along with some genes such as ß-catenin. While BCL-3 was associated with a higher stage of CRC, ß-catenin didn't show such a relationship with CRC.

MicroRNA-627-5p inhibits the proliferation of hepatocellular carcinoma cells by targeting BCL3 transcription coactivator.

Hepatocellular carcinoma (HCC) is a common malignant tumour. An increasing number of studies indicate that microRNAs (miRNAs) are critical regulators in the carcinogenesis and progression of HCC. MiR-627-5p has been identified as a tumour suppressor in colorectal cancer and glioblastoma multiforme. However, the function of miR-627-5p in HCC progression remains unclear yet. In our present study, miR-627-5p was determined to be low-expressed in HCC tissues and cell lines. Furthermore, miR-627-5p was expressed at significantly lower levels in HCC tissues with tumour size >5 cm or advanced tumour stages (III+IV). Additionally, HCC patients with low miR-627-5p level had a significantly poorer overall survival. Functionally, ectopic expression of miR-627-5p obviously inhibited the proliferation, and induced G1 phase arrest and apoptosis of Hep3B and SMMC-7721 cells. Conversely, miR-627-5p silencing facilitated HCC cell proliferation, cell cycle progression and apoptosis resistance. In vivo experiments further confirmed that miR-627-5p overexpression repressed the growth of Hep3B cells in mice. Mechanistically, BCL3 transcription coactivator was predicted as a direct target of miR-627-5p. MiR-627-5p overexpression reduced, whereas miR-627-5p knockdown enhanced the expression of BCL3 protein in HCC cells. Luciferase reporter assay confirmed the direct binding between miR-627-5p and 3'UTR of BCL3. The expression of BCL3 protein was negatively correlated with miR-627-5p level in HCC tissues. More importantly, re-expression of BCL3 partially reversed miR-627-5p induced inhibitory effects on Hep3B cells. In conclusion, these results demonstrated that miR-627-5p functioned as a tumour suppressor in HCC possibly by attenuating BCL3. This finding might offer a new therapeutic target for HCC treatment.

The proto-oncogene Bcl3 induces immune checkpoint PD-L1 expression, mediating proliferation of ovarian cancer cells.

The proto-oncogene Bcl3 induces survival and proliferation in cancer cells; however, its function and regulation in ovarian cancer (OC) remain unknown. Here, we show that Bcl3 expression is increased in human OC tissues. Surprisingly, however, we found that in addition to promoting survival, proliferation, and migration of OC cells, Bcl3 promotes both constitutive and interferon-γ (IFN)-induced expression of the immune checkpoint molecule PD-L1. The Bcl3 expression in OC cells is further increased by IFN, resulting in increased PD-L1 transcription. The mechanism consists of an IFN-induced, Bcl3- and p300-dependent PD-L1 promoter occupancy by Lys-314/315 acetylated p65 NF-κB. Blocking PD-L1 by neutralizing antibody reduces proliferation of OC cells overexpressing Bcl3, suggesting that the pro-proliferative effect of Bcl3 in OC cells is partly mediated by PD-L1. Together, this work identifies PD-L1 as a novel target of Bcl3, and links Bcl3 to IFNγ signaling and PD-L1-mediated immune escape.

Bcl-3 induced by IL-22 via STAT3 activation acts as a potentiator of psoriasis-related gene expression in epidermal keratinocytes.

IL-22 induces STAT3 phosphorylation and mediates psoriasis-related gene expression. However, the signaling mechanism leading from pSTAT3 to the expression of these genes remains unclear. We focused on Bcl-3, which is induced by STAT3 activation and mediates gene expression. In cultured human epidermal keratinocytes, IL-22 increased Bcl-3, which was translocated to the nucleus with p50 via STAT3 activation. The increases in CXCL8, S100As and human ß-defensin 2 mRNA expression caused by IL-22 were abolished by siRNA against Bcl-3. Although CCL20 expression was also augmented by IL-22, the knockdown of Bcl-3 increased its level. Moreover, the combination of IL-22 and IL-17A enhanced Bcl-3 production, IL-22-induced gene expression, and the expression of other psoriasis-related genes, including those encoding IL-17C, IL-19, and IL-36γ. The expression of these genes (except for CCL20) was also suppressed by the knockdown of Bcl-3. Bcl-3 overexpression induced CXCL8 and HBD2 expression but not S100As expression. We also compared Bcl-3 expression between psoriatic skin lesions and normal skin. Immunostaining revealed strong signals for Bcl-3 and p50 in the nucleus of epidermal keratinocytes from psoriatic skin. The IL-22-STAT3-Bcl-3 pathway may be important in the pathogenesis of psoriasis.

Balanced Bcl-3 expression in murine CD4+ T cells is required for generation of encephalitogenic Th17 cells.

The function of NF-κB family members is controlled by multiple mechanisms including the transcriptional regulator Bcl-3, an atypical member of the IκB family. By using a murine model of conditional Bcl-3 overexpression specifically in T cells, we observed impairment in the development of Th2, Th1, and Th17 cells. High expression of Bcl-3 promoted CD4+ T-cell survival, but at the same time suppressed proliferation in response to TCR stimulation, resulting in reduced CD4+ T-cell expansion. As a consequence, T-cell-specific overexpression of Bcl-3 led to reduced inflammation in the small intestine of mice applied with anti-CD3 in a model of gut inflammation. Moreover, impaired Th17-cell development resulted in the resistance of Bcl-3 overexpressing mice to EAE, a mouse model of multiple sclerosis. Thus, we concluded that fine-tuning expression of Bcl-3 is needed for proper CD4+ T-cell development and is required to sustain Th17-cell mediated pathology.

Immunohistochemical assessment of Survivin and Bcl3 expression as potential biomarkers for NF-κB activation in the Barrett metaplasia-dysplasia-adenocarcinoma sequence.

Non-dysplastic Barrett's oesophagus (NDBE) occurs as a consequence of an inflammatory response triggered through prolonged gastro-oesophageal reflux and it may precede the development of oesophageal adenocarcinoma. NF-κB activation as a result of the inflammatory response has been shown in NDBE, but the possible mechanism involved in the process is unknown. The aim of this study was to assess, using immunohistochemistry, Survivin and Bcl3 expression as potential biomarkers for NF-κB activation along the oesophageal metaplasia-dysplasia-adenocarcinoma sequence. Survivin is an NF-κB-inducible anti-apoptotic protein, and Bcl3 is a negative regulator of NF-κB. There was progressive upregulation of Survivin expression along the oesophageal metaplasia-dysplasia-adenocarcinoma sequence. Bcl3 expression was upregulated in non-dysplastic Barrett's oesophagus, low-grade, high-grade dysplasia and oesophageal adenocarcinoma when compared to squamous group. The study shows the differential expression of Bcl3 between the squamous and Barrett's stage, suggesting that Bcl3 could be a surrogate marker for early event involving constitutive NF-κB activation. In addition, the study suggests that NF-κB activation may infer resistance to apoptosis through the expression of anti-apoptotic genes such as Survivin, which showed progressive increase in expression throughout the oesophageal metaplasia-dysplasia-adenocarcinoma sequence. This ability to avoid apoptosis may underlie the persistence and malignant predisposition of Barrett's metaplasia.

The B-cell-activating factor signalling pathway is associated with Helicobacter pylori independence in gastric mucosa-associated lymphoid tissue lymphoma without t(11;18)(q21;q21).

We previously reported that activation of the B-cell-activating factor (BAFF) pathway upregulates nuclear factor-κB (NF-κB) and induces BCL3 and BCL10 nuclear translocation in Helicobacter pylori (HP)-independent gastric diffuse large B-cell lymphoma (DLBCL) tumours with evidence of mucosa-associated lymphoid tissue (MALT). However, the significance of BAFF expression in HP independence of gastric low-grade MALT lymphomas without t(11;18)(q21;q21) remains unexplored. Sixty-four patients who underwent successful HP eradication for localized HP-positive gastric MALT lymphomas without t(11;18)(q21;q21) were studied. BAFF expression was significantly higher in the HP-independent group than in the HP-dependent group [22/26 (84.6%) versus 8/38 (21.1%); p < 0.001]. Similarly, BAFF receptor (BAFF-R) expression (p = 0.004) and nuclear BCL3 (p = 0.004), BCL10 (p < 0.001), NF-κB (p65) (p = 0.001) and NF-κB (p52) (p = 0.005) expression were closely correlated with the HP independence of these tumours. Moreover, BAFF overexpression was significantly associated with BAFF-R expression and nuclear BCL3, BCL10, NF-κB (p65) and NF-κB (p52) expression. These findings were further validated in an independent cohort, including 40 HP-dependent cases and 18 HP-independent cases of gastric MALT lymphoma without t(11;18)(q21;q21). The biological significance of BAFF signalling in t(11;18)(q21;q21)-negative lymphoma cells was further studied in two types of lymphoma B cell: OCI-Ly3 [non-germinal centre B-cell origin DLBCL without t(11;18)(q21;q21) cell line] and MA-1 [t(14;18)(q32;q21)/IGH-MALT1-positive DLBCL cell line]. In both cell lines, we found that BAFF activated the canonical NF-κB and AKT pathways, and induced the formation of BCL10-BCL3 complexes, which translocated to the nucleus. BCL10 and BCL3 nuclear translocation and NF-κB (p65) transactivation were inhibited by either LY294002 or by silencing BCL3 or BCL10 with small interfering RNA. BAFF also activated non-canonical NF-κB pathways (p52) through tumour necrosis factor receptor-associated factor 3 degradation, NF-κB-inducing kinase accumulation, inhibitor of κB kinase (IKK) α/ß phosphorylation and NF-κB p100 processing in both cell lines. Our data indicate that the autocrine BAFF signal transduction pathway contributes to HP independence in gastric MALT lymphomas without the t(11;18)(q21;q21) translocation. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The Nuclear Protein IκBζ Forms a Transcriptionally Active Complex with Nuclear Factor-κB (NF-κB) p50 and the Lcn2 Promoter via the N- and C-terminal Ankyrin Repeat Motifs.

The nuclear protein IκBζ, comprising the N-terminal trans-activation domain and the C-terminal ankyrin repeat (ANK) domain composed of seven ANK motifs, activates transcription of a subset of nuclear factor-κB (NF-κB)-dependent innate immune genes such as Lcn2 encoding the antibacterial protein lipocalin-2. Lcn2 activation requires formation of a complex containing IκBζ and NF-κB p50, a transcription factor that harbors the DNA-binding Rel homology region but lacks a trans-activation domain, on the promoter with the canonical NF-κB-binding site (κB site) and its downstream cytosine-rich element. Here we show that IκBζ productively interacts with p50 via Asp-451 in the N terminus of ANK1, a residue that is evolutionarily conserved among IκBζ and the related nuclear IκB proteins Bcl-3 and IκBNS Threonine substitution for Asp-451 abrogates direct association with the κB-site-binding protein p50, complex formation with the Lcn2 promoter DNA, and activation of Lcn2 transcription. The basic residues Lys-717 and Lys-719 in the C-terminal region of ANK7 contribute to IκBζ binding to the Lcn2 promoter, probably via interaction with the cytosine-rich element required for Lcn2 activation; glutamate substitution for both lysines results in a loss of transcriptionally active complex formation without affecting direct contact of IκBζ with p50. Both termini of the ANK domain in Bcl-3 and IκBNS function in a manner similar to that of IκBζ to interact with promoter DNA, indicating a common mechanism in which the nuclear IκBs form a regulatory complex with NF-κB and promoter DNA via the invariant aspartate in ANK1 and the conserved basic residues in ANK7.

CEA-producing multiple myeloma with meningeal invasion during relapse.

Here we describe the case of a 62-year-old woman diagnosed with multiple myeloma (IgA-κ type) who had a high serum CEA level of 27.7 ng/ml. Upper and lower gastrointestinal endoscopy and PET/CT scan showed no abnormality. After two courses of VAD therapy, the serum CEA level decreased to 5.7 ng/ml, with a decrease in the IgA level, suggesting the diagnosis of CEA-producing myeloma. After 4 years and 1 month, she had a relapse with an increase in the LDH level and myeloma cells in the blood, followed by cognitive loss and convulsion. She died 1 month after the onset of neurological symptoms. Several myeloma cells were detected in the cerebral spinal fluid, which suggested the diagnosis of myelomatous meningitis. Myelomatous meningitis is a rare disease and accounts for 1% of all myelomas. This is the fourth reported case of CEA-producing myeloma.