Gene Summary

Gene:REL; v-rel avian reticuloendotheliosis viral oncogene homolog
Aliases: C-Rel
Summary:This gene encodes a protein that belongs to the Rel homology domain/immunoglobulin-like fold, plexin, transcription factor (RHD/IPT) family. Members of this family regulate genes involved in apoptosis, inflammation, the immune response, and oncogenic processes. This proto-oncogene plays a role in the survival and proliferation of B lymphocytes. Mutation or amplification of this gene is associated with B-cell lymphomas, including Hodgkin's lymphoma. Single nucleotide polymorphisms in this gene are associated with susceptibility to ulcerative colitis and rheumatoid arthritis. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Apr 2014]
Databases:OMIM, HGNC, GeneCard, Gene
Protein:proto-oncogene c-Rel
Source:NCBIAccessed: 06 August, 2015


What does this gene/protein do?
Show (11)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 06 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Hodgkin Lymphoma
  • Breast Cancer
  • Proto-Oncogenes
  • Mutation
  • Cancer Gene Expression Regulation
  • Cell Proliferation
  • B-Cell Lymphoma
  • DNA
  • Proto-Oncogene Proteins c-rel
  • Gene Amplification
  • NF-kappa B
  • Gene Expression Profiling
  • Molecular Sequence Data
  • Gene Expression
  • Immunohistochemistry
  • Genes, rel
  • Signal Transduction
  • DNA-Binding Proteins
  • Transfection
  • Transcription Factors
  • Cancer DNA
  • Transcriptional Activation
  • Neoplasm Proteins
  • Amino Acid Sequence
  • Proto-Oncogene Proteins
  • Promoter Regions
  • FISH
  • Diffuse Large B-Cell Lymphoma
  • Cell Nucleus
  • Neoplastic Cell Transformation
  • Base Sequence
  • Apoptosis
  • I-kappa B Proteins
  • Oncogene Proteins v-rel
  • Chromosome Aberrations
  • Polyploidy
  • Nuclear Proteins
  • Protein Precursors
  • Chromosome 2
  • Translocation
Tag cloud generated 06 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: REL (cancer-related)

Moorchung N, Kunwar S, Ahmed KW
An evaluation of nuclear factor kappa B expression in colorectal carcinoma: an analysis of 50 cases.
J Cancer Res Ther. 2014 Jul-Sep; 10(3):631-5 [PubMed] Related Publications
CONTEXT: There is a rising trend in the incidence of (colorectal carcinoma) colorectal cancer (CRC) in India. Nuclear factor kappa B (NFkB) is a transcription factor which belongs to the Rel family. It has an impact on phenomena such as apoptosis, tumor progression and differentiation.
AIMS: (1) To evaluate the grade and stage in 50 cases of colorectal carcinoma. (2) To evaluate the NFkB translocation into the nucleus of the cells. (3) To compare the benign and malignant areas with the degree of NFkB translocation and compare the translocation with the grade and pathological stage.
SUBJECTS AND METHODS: The grade and stage of the tumors was evaluated. NFkB staining was performed on the tissues. The results of the immunostaining were analyzed semi quantitatively as a percentage of positive cells.
STATISTICAL ANALYSIS USED:  Statistical Package for Social Sciences 13.0 statistical package program (SPSS, Lead Technologies Inc, USA) for windows was used. Correlation was carried out using the Pearson's correlation co-efficient and the Chi-square test.
RESULTS: There were 29 males (58%) and 21 females (42%). Most of the cases were well-differentiated adenocarcinomas (58%). There was a significant difference between NFkB translocation in the epithelial cells and lymphocytes in the benign and malignant areas (P - 0.04 and P - 0.001 respectively). There was a significant correlation between the grade of NFkB staining in the malignant epithelial cells with the tumor and nodal status (P - 0.001 and P - 0.001).
CONCLUSIONS: It is likely that NFkB is an important factor in the pathogenesis of CRC. Further studies including therapeutic intervention using strategies which prevent activation of NFkB in colorectal carcinoma patients will tell if we could alter the course of the disease favorably.

Geismann C, Grohmann F, Sebens S, et al.
c-Rel is a critical mediator of NF-κB-dependent TRAIL resistance of pancreatic cancer cells.
Cell Death Dis. 2014; 5:e1455 [PubMed] Free Access to Full Article Related Publications
Pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest malignancies with an overall life expectancy of 6 months despite current therapies. NF-κB signalling has been shown to be critical for this profound cell-autonomous resistance against chemotherapeutic drugs and death receptor-induced apoptosis, but little is known about the role of the c-Rel subunit in solid cancer and PDAC apoptosis control. In the present study, by analysis of genome-wide patterns of c-Rel-dependent gene expression, we were able to establish c-Rel as a critical regulator of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in PDAC. TRAIL-resistant cells exhibited a strong TRAIL-inducible NF-κB activity, whereas TRAIL-sensitive cells displayed only a small increase in NF-κB-binding activity. Transfection with siRNA against c-Rel sensitized the TRAIL-resistant cells in a manner comparable to siRNA targeting the p65/RelA subunit. Gel-shift analysis revealed that c-Rel is part of the TRAIL-inducible NF-κB complex in PDAC. Array analysis identified NFATc2 as a c-Rel target gene among the 12 strongest TRAIL-inducible genes in apoptosis-resistant cells. In line, siRNA targeting c-Rel strongly reduced TRAIL-induced NFATc2 activity in TRAIL-resistant PDAC cells. Furthermore, siRNA targeting NFATc2 sensitized these PDAC cells against TRAIL-induced apoptosis. Finally, TRAIL-induced expression of COX-2 was diminished through siRNA targeting c-Rel or NFATc2 and pharmacologic inhibition of COX-2 with celecoxib or siRNA targeting COX-2, enhanced TRAIL apoptosis. In conclusion, we were able to delineate a novel c-Rel-, NFATc2- and COX-2-dependent antiapoptotic signalling pathway in PDAC with broad clinical implications for pharmaceutical intervention strategies.

Neo WH, Lim JF, Grumont R, et al.
c-Rel regulates Ezh2 expression in activated lymphocytes and malignant lymphoid cells.
J Biol Chem. 2014; 289(46):31693-707 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
The polycomb group protein Ezh2 is a histone methyltransferase that modifies chromatin structure to alter gene expression during embryonic development, lymphocyte activation, and tumorigenesis. The mechanism by which Ezh2 expression is regulated is not well defined. In the current study, we report that c-Rel is a critical activator of Ezh2 transcription in lymphoid cells. In activated primary murine B and T cells, plus human leukemia and multiple myeloma cell lines, recruitment of c-Rel to the first intron of the Ezh2 locus promoted Ezh2 mRNA expression. This up-regulation was abolished in activated c-Rel-deficient lymphocytes and by c-Rel knockdown in Jurkat T cells. Treatment of malignant cells with the c-Rel inhibitor pentoxifylline not only reduced c-Rel nuclear translocation and Ezh2 expression, but also enhanced their sensitivity to the Ezh2-specific drug, GSK126 through increased growth inhibition and cell death. In summary, our demonstration that c-Rel regulates Ezh2 expression in lymphocytes and malignant lymphoid cells reveals a novel transcriptional network in transformed lymphoid cells expressing high levels of Ezh2 that provides a molecular justification for combinatorial drug therapy.

Iannetti A, Ledoux AC, Tudhope SJ, et al.
Regulation of p53 and Rb links the alternative NF-κB pathway to EZH2 expression and cell senescence.
PLoS Genet. 2014; 10(9):e1004642 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
There are two major pathways leading to induction of NF-κB subunits. The classical (or canonical) pathway typically leads to the induction of RelA or c-Rel containing complexes, and involves the degradation of IκBα in a manner dependent on IκB kinase (IKK) β and the IKK regulatory subunit NEMO. The alternative (or non-canonical) pathway, involves the inducible processing of p100 to p52, leading to the induction of NF-κB2(p52)/RelB containing complexes, and is dependent on IKKα and NF-κB inducing kinase (NIK). Here we demonstrate that in primary human fibroblasts, the alternative NF-κB pathway subunits NF-κB2 and RelB have multiple, but distinct, effects on the expression of key regulators of the cell cycle, reactive oxygen species (ROS) generation and protein stability. Specifically, following siRNA knockdown, quantitative PCR, western blot analyses and chromatin immunoprecipitation (ChIP) show that NF-κB2 regulates the expression of CDK4 and CDK6, while RelB, through the regulation of genes such as PSMA5 and ANAPC1, regulates the stability of p21WAF1 and the tumour suppressor p53. These combine to regulate the activity of the retinoblastoma protein, Rb, leading to induction of polycomb protein EZH2 expression. Moreover, our ChIP analysis demonstrates that EZH2 is also a direct NF-κB target gene. Microarray analysis revealed that in fibroblasts, EZH2 antagonizes a subset of p53 target genes previously associated with the senescent cell phenotype, including DEK and RacGAP1. We show that this pathway provides the major route of crosstalk between the alternative NF-κB pathway and p53, a consequence of which is to suppress cell senescence. Importantly, we find that activation of NF-κB also induces EZH2 expression in CD40L stimulated cells from Chronic Lymphocytic Leukemia patients. We therefore propose that this pathway provides a mechanism through which microenvironment induced NF-κB can inhibit tumor suppressor function and promote tumorigenesis.

Giordano M, Roncagalli R, Bourdely P, et al.
The tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) imposes a brake on antitumor activity of CD8 T cells.
Proc Natl Acad Sci U S A. 2014; 111(30):11115-20 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
The transcription factor NF-κB is central to inflammatory signaling and activation of innate and adaptive immune responses. Activation of the NF-κB pathway is tightly controlled by several negative feedback mechanisms, including A20, an ubiquitin-modifying enzyme encoded by the tnfaip3 gene. Mice with selective deletion of A20 in myeloid, dendritic, or B cells recapitulate some human inflammatory pathology. As we observed high expression of A20 transcripts in dysfunctional CD8 T cells in an autochthonous melanoma, we analyzed the role of A20 in regulation of CD8 T-cell functions, using mice in which A20 was selectively deleted in mature conventional T cells. These mice developed lymphadenopathy and some organ infiltration by T cells but no splenomegaly and no detectable pathology. A20-deleted CD8 T cells had increased sensitivity to antigen stimulation with production of large amounts of IL-2 and IFNγ, correlated with sustained nuclear expression of NF-κB components reticuloendotheliosis oncogene c-Rel and p65. Overexpression of A20 by retroviral transduction of CD8 T cells dampened their intratumor accumulation and antitumor activity. In contrast, relief from the A20 brake in NF-κB activation in adoptively transferred antitumor CD8 T cells led to improved control of melanoma growth. Tumor-infiltrating A20-deleted CD8 T cells had enhanced production of IFNγ and TNFα and reduced expression of the inhibitory receptor programmed cell death 1. As manipulation of A20 expression in CD8 T cells did not result in pathologic manifestations in the mice, we propose it as a candidate to be targeted to increase antitumor efficiency of adoptive T-cell immunotherapy.

Chang TP, Kim M, Vancurova I
Analysis of TGFβ1 and IL-10 transcriptional regulation in CTCL cells by chromatin immunoprecipitation.
Methods Mol Biol. 2014; 1172:329-41 [PubMed] Related Publications
The immunosuppressive cytokines transforming growth factor β1 (TGFβ1) and interleukin-10 (IL-10) regulate a variety of biological processes including differentiation, proliferation, tissue repair, tumorigenesis, inflammation, and host defense. Aberrant expression of TGFβ1 and IL-10 has been associated with many types of autoimmune and inflammatory disorders, as well as with many types of cancer and leukemia. Patients with cutaneous T cell lymphoma (CTCL) have high levels of malignant CD4+ T cells expressing IL-10 and TGFβ1 that suppress the immune system and diminish the antitumor responses. The transcriptional regulation of TGFβ1 and IL-10 expression is orchestrated by several transcription factors, including NFκB. However, while the transcriptional regulation of pro-inflammatory and anti-apoptotic genes by NFκB has been studied extensively, much less is known about the NFκB regulation of immunosuppressive genes. In this chapter, we describe a protocol that uses chromatin immunoprecipitation (ChIP) to analyze the transcriptional regulation of TGFβ1 and IL-10 by measuring recruitment of NFκB p65, p50, c-Rel, Rel-B, and p52 subunits to TGFβ1 and IL-10 promoters in human CTCL Hut-78 cells.

Kwiecinska A, Ichimura K, Berglund M, et al.
Amplification of 2p as a genomic marker for transformation in lymphoma.
Genes Chromosomes Cancer. 2014; 53(9):750-68 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
To outline further genetic mechanisms of transformation from follicular lymphoma (FL) to diffuse large B-cell lymphoma (DLBCL), we have performed whole genome array-CGH in 81 tumors from 60 patients [29 de novo DLBCL (dnDLBCL), 31 transformed DLBCL (tDLBCL), and 21 antecedent FL]. In 15 patients, paired tumor samples (primary FL and a subsequent tDLBCL) were available, among which three possessed more than two subsequent tumors, allowing us to follow specific genetic alterations acquired before, during, and after the transformation. Gain of 2p15-16.1 encompassing, among others, the REL, BCL11A, USP34, COMMD1, and OTX1 genes was found to be more common in the tDLBCL compared with dnDLBCL (P < 0.001). Furthermore, a high-level amplification of 2p15-16.1 was also detected in the FL stage prior to transformation, indicating its importance during the transformation event. Quantitative real-time PCR showed a higher level of amplification of REL, USP34, and COMMD1 (all involved in the NFκΒ-pathway) compared with BCL11A, which indicates that the altered genes disrupting the NFκΒ pathway may be the driver genes of transformation rather than the previously suggested BCL11A. Moreover, a 17q21.33 amplification was exclusively found in tDLBCL, never in FL (P < 0.04) or dnDLBCL, indicating an upregulation of genes of importance during the later phase of transformation. Taken together, our study demonstrates potential genomic markers for disease progression to clinically more aggressive forms. We also confirm the importance of the TP53-, CDKN2A-, and NFκΒ-pathways for the transformation from FL to DLBCL.

Muvaffak A, Pan Q, Yan H, et al.
Evaluating TBK1 as a therapeutic target in cancers with activated IRF3.
Mol Cancer Res. 2014; 12(7):1055-66 [PubMed] Related Publications
UNLABELLED: TBK1 (TANK-binding kinase 1) is a noncanonical IκB protein kinase that phosphorylates and activates downstream targets such as IRF3 and c-Rel and, mediates NF-κB activation in cancer. Previous reports demonstrated synthetic lethality of TBK1 with mutant KRAS in non-small cell lung cancer (NSCLC); thus, TBK1 could be a novel target for treatment of KRAS-mutant NSCLC. Here, the effect of TBK1 on proliferation in a panel of cancer cells by both genetic and pharmacologic approaches was evaluated. In KRAS-mutant cancer cells, reduction of TBK1 activity by knockdown or treatment with TBK1 inhibitors did not correlate with reduced proliferation in a two-dimensional viability assay. Verification of target engagement via reduced phosphorylation of S386 of IRF3 (pIRF3(S386)) was difficult to assess in NSCLC cells due to low protein expression. However, several cell lines were identified with high pIRF3(S386) levels after screening a large panel of cell lines, many of which also harbor KRAS mutations. Specifically, a large subset of KRAS-mutant pancreatic cancer cell lines was uncovered with high constitutive pIRF3(S386) levels, which correlated with high levels of phosphorylated S172 of TBK1 (pTBK1(S172)). Finally, TBK1 inhibitors dose-dependently inhibited pIRF3(S386) in these cell lines, but this did not correlate with inhibition of cell growth. Taken together, these data demonstrate that the regulation of pathways important for cell proliferation in some NSCLC, pancreatic, and colorectal cell lines is not solely dependent on TBK1 activity.
IMPLICATIONS: TBK1 has therapeutic potential under certain contexts and phosphorylation of its downstream target IRF3 is a biomarker of TBK1 activity.

Odqvist L, Montes-Moreno S, Sánchez-Pacheco RE, et al.
NFκB expression is a feature of both activated B-cell-like and germinal center B-cell-like subtypes of diffuse large B-cell lymphoma.
Mod Pathol. 2014; 27(10):1331-7 [PubMed] Related Publications
The activation of nuclear factor kappa B (NFκB) transcription factor family is considered to have a key role in diffuse large B-cell lymphoma (DLBCL) pathogenesis and is associated with a specific molecular subtype, the activated B-cell-like (ABC) subtype. We evaluated the expression of NFκB by immunohistochemistry in a large series of DLBCL cases. The five different NFκB family members (NFκB1, NFκB2, RELA, RELB, and REL) showed a heterogeneous expression pattern with the vast majority of cases being positive for at least one factor. Two independent series of tumor samples were classified into germinal center B-cell-like (GCB) or ABC subtypes using different approaches, immunohistochemistry, or gene expression profiling, and the expression of NFκB family members was assessed. Notably, no significant differences regarding the expression of the different NFκB members were detected between the two subtypes, suggesting that NFκB signaling is a prominent feature not only in the ABC subtype, but also in the GCB tumors. Of the five transcription factors, only REL expression had a significant clinical impact on R-CHOP-treated diffuse large B-cell lymphoma, identifying a subgroup of patients with superior clinical outcome.

Haery L, Lugo-Picó JG, Henry RA, et al.
Histone acetyltransferase-deficient p300 mutants in diffuse large B cell lymphoma have altered transcriptional regulatory activities and are required for optimal cell growth.
Mol Cancer. 2014; 13:29 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
BACKGROUND: Recent genome-wide studies have shown that approximately 30% of diffuse large B-cell lymphoma (DLBCL) cases harbor mutations in the histone acetyltransferase (HAT) coactivators p300 or CBP. The majority of these mutations reduce or eliminate the catalytic HAT activity. We previously demonstrated that the human DLBCL cell line RC-K8 expresses a C-terminally truncated, HAT-defective p300 protein (p300ΔC-1087), whose expression is essential for cell proliferation.
METHODS: Using results from large-scale DLBCL studies, we have identified and characterized a second C-terminally truncated, HAT-defective p300 mutant, p300ΔC-820, expressed in the SUDHL2 DLBCL cell line. Properties of p300ΔC-820 were characterized in the SUDHL2 DLBCL cell line by Western blotting, co-immunoprecipitation, and shRNA gene knockdown, as well by using cDNA expression vectors for p300ΔC-820 in pull-down assays, transcriptional reporter assays, and immunofluorescence experiments. A mass spectrometry-based method was used to compare the histone acetylation profile of DLBCL cell lines expressing various levels of wild-type p300.
RESULTS: We show that the SUDHL2 cell line expresses a C-terminally truncated, HAT-defective form of p300 (p300ΔC-820), but no wild-type p300. The p300ΔC-820 protein has a wild-type ability to localize to subnuclear "speckles," but has a reduced ability to enhance transactivation by transcription factor REL. Knockdown of p300ΔC-820 in SUDHL2 cells reduced their proliferation and soft agar colony-forming ability. In RC-K8 cells, knockdown of p300ΔC-1087 resulted in increased expression of mRNA and protein for REL target genes A20 and IκBα, two genes that have been shown to limit the growth of RC-K8 cells when overexpressed. Among a panel of B-lymphoma cell lines, low-level expression of full-length p300 protein, which is characteristic of the SUDHL2 and RC-K8 cells, was associated with decreased acetylation of histone H3 at lysines 14 and 18.
CONCLUSIONS: The high prevalence of p300 mutations in DLBCL suggests that HAT-deficient p300 activity defines a subtype of DLBCL, which we have investigated using human DLBCL cell lines RC-K8 and SUDHL2. Our results suggest that truncated p300 proteins contribute to DLBCL cell growth by affecting the expression of specific genes, perhaps through a mechanism that involves alterations in global histone acetylation.

Xie C, Powell C, Yao M, et al.
Ubiquitin-conjugating enzyme E2C: a potential cancer biomarker.
Int J Biochem Cell Biol. 2014; 47:113-7 [PubMed] Related Publications
The ubiquitin-conjugating enzymes 2C (UBE2C) is an integral component of the ubiquitin proteasome system. UBE2C consists of a conserved core domain containing the catalytic Cys residue and an N-terminal extension. The core domain is required for ubiquitin adduct formation by interacting with the ubiquitin-fold domain in the E1 enzyme, and contributes to the E3 enzyme binding. UBE2C N-terminal extension regulates E3 enzyme activity as a part of an intrinsic inhibitory mechanism. UBE2C is required for the destruction of mitotic cyclins and securin, which are essential for spindle assembly checkpoint and mitotic exit. The UBE2C mRNA and/or protein levels are aberrantly increased in many cancer types with poor clinical outcomes. Accumulation of UBE2C stimulates cell proliferation and anchorage-independent growth. UBE2C transgenic mice are prone to develop spontaneous tumors and carcinogen-induced tumor with evidence of chromosome aneuploidy.

Gong Y, Cao Y, Song L, et al.
HMGB3 characterization in gastric cancer.
Genet Mol Res. 2013; 12(4):6032-9 [PubMed] Related Publications
Gastric cancer is a major health problem worldwide; it is the second most common cause of cancer death in the world. Recent studies indicate that the high-mobility group (HMG) of chromosomal proteins is associated with cancer progression. However, HMGB3 has been little studied. We analyzed the co-expression network between HMGB3 and differentially-expressed genes in the GSE17187 database, identifying the relevant transcription factors, and the conserved domain of HMGB3 to understand the underlying regulation mechanisms involved in gastric cancer. Thirty-one relationships between 11 differentially-expressed genes were included in a co-expression network; many of these genes have been identified as related to cancer, including TBX5 and TFR2. Further analysis identified nine transcription factors, these being GATA3, MZF1, GATA1, GATA2, SRY, REL, NFYB, NFYC, and NFYA, which could interact with HMGB3 to regulate target gene expression and consequently regulate gastric cancer cell proliferation, migration and invasion. The HMG-box domain was very similar in various species, with only a few amino acid changes, indicating conserved functions in HMG-box. This information helps to provide insight into the molecular mechanisms of HMGB3 in human gastric cancer.

Emery SM, Alotaibi MR, Tao Q, et al.
Combined antiproliferative effects of the aminoalkylindole WIN55,212-2 and radiation in breast cancer cells.
J Pharmacol Exp Ther. 2014; 348(2):293-302 [PubMed] Related Publications
The potential antitumor activity of cannabinoid receptor agonists, such as the aminoalklylindole WIN55,212-2 (WIN2), has been studied extensively, but their potential interaction with conventional cancer therapies, such as radiation, remains unknown. In the present work, the influence of WIN2 on the antiproliferative activity of radiation in human (MCF-7 and MDA-MB231) and murine (4T1) breast cancer cells was investigated. The antiproliferative effects produced by combination of WIN2 and radiation were more effective than either agent alone. The stereoisomer of WIN2, WIN55,212-3 (WIN3), failed to inhibit growth or potentiate the growth-inhibitory effects of radiation, indicative of stereospecificity. Two other aminoalkylindoles, pravadoline and JWH-015 [(2-methyl-1-propyl-1H-indol-3-yl)-1-naphthalenyl-methanone], also enhanced the antiproliferative effects of radiation, but other synthetic cannabinoids (i.e., nabilone, CP55,940 [(+)-rel-5-(1,1-dimethylheptyl)-2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]-phenol], and methanandamide) or phytocannabinoids [i.e., Δ⁹-tetrahydrocannabinol (THC) and cannabidiol] did not. The combination treatment of WIN2 + radiation promoted both autophagy and senescence but not apoptosis or necrosis. WIN2 also failed to alter radiation-induced DNA damage or the apparent rate of DNA repair. Although the antiproliferative actions of WIN2 were mediated through noncannabinoid receptor-mediated pathways, the observation that WIN2 interfered with growth stimulation by sphingosine-1-phosphate (S1P) implicates the potential involvement of S1P/ceramide signaling pathways. In addition to demonstrating that aminoalkylindole compounds could potentially augment the effectiveness of radiation treatment in breast cancer, the present study suggests that THC and nabilone are unlikely to interfere with the effectiveness of radiation therapy, which is of particular relevance to patients using cannabinoid-based drugs to ameliorate the toxicity of cancer therapies.

Tordella L, Koch S, Salter V, et al.
ASPP2 suppresses squamous cell carcinoma via RelA/p65-mediated repression of p63.
Proc Natl Acad Sci U S A. 2013; 110(44):17969-74 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
Squamous cell carcinoma (SCC) is highly malignant and refractory to therapy. The majority of existing mouse SCC models involve multiple gene mutations. Very few mouse models of spontaneous SCC have been generated by a single gene deletion. Here we report a haploinsufficient SCC mouse model in which exon 3 of the Tp53BP2 gene (a p53 binding protein) was deleted in one allele in a BALB/c genetic background. Tp53BP2 encodes ASPP2 (ankyrin repeats, SH3 domain and protein rich region containing protein 2). Keratinocyte differentiation induces ASPP2 and its expression is inversely correlated with p63 protein in vitro and in vivo. Up-regulation of p63 expression is required for ASPP2(Δexon3/+) BALB/c mice to develop SCC, as heterozygosity of p63 but not p53 prevents them from developing it. Mechanistically, ASPP2 inhibits ΔNp63 expression through its ability to bind IκB and enhance nuclear Rel/A p65, a component of the NF-κB transcription complex, which mediates the repression of p63. Reduced ASPP2 expression associates with tumor metastasis and increased p63 expression in human head and neck SCCs. This study identifies ASPP2 as a tumor suppressor that suppresses SCC via inflammatory signaling through NF-κB-mediated repression of p63.

Neven B, Mamessier E, Bruneau J, et al.
A Mendelian predisposition to B-cell lymphoma caused by IL-10R deficiency.
Blood. 2013; 122(23):3713-22 [PubMed] Related Publications
Monogenic interleukin-10 (IL-10) and IL-10 receptor (IL-10R) deficiencies cause very early onset severe inflammatory bowel disease. Here, we report that 5 patients with an IL-10R1 (n = 1) or IL-10R2 (n = 4) deficiency developed B-cell non-Hodgkin lymphoma between the ages of 5 and 6 years (which was recurrent in 1 patient). These lymphomas had some of the characteristics of diffuse large B-cell lymphomas and contained monoclonal, Epstein-Barr virus-negative germinal center B cells. The tumors displayed a remarkably homogeneous signature, with original activation of the nuclear factor κB pathway and a decrease in intratumor T-cell infiltration. Hence, IL-10R deficiency is associated with a high risk of developing B-cell lymphoma. Our results revealed an unexpected role of the IL-10R pathway in lymphomagenesis.

Yu Q, Zhou C, Wang J, et al.
A functional insertion/deletion polymorphism in the promoter of PDCD6IP is associated with the susceptibility of hepatocellular carcinoma in a Chinese population.
DNA Cell Biol. 2013; 32(8):451-7 [PubMed] Related Publications
Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Apart from environmental factors such as hepatitis B virus (HBV) or hepatitis C virus, alcohol abuse, and exposure to dietary aflatoxin, genetic factors are also involved in the pathogenesis of HCC. By analyzing 390 HCC cases and 431 healthy controls in a Chinese population, we used a candidate gene approach to evaluate the association between a 15-bp insertion/deletion (indel) polymorphism (rs28381975) in the promoter region of the programmed cell death 6 interacting protein (PDCD6IP) gene and HCC susceptibility. Logistic regression analysis demonstrated that subjects carrying ins/del or ins/ins genotypes had significantly increased risk for HCC than individuals carrying del/del genotypes (adjusted odds ratio=1.39, 95% confidence interval=1.01-1.91, p=0.033]. Carrying the 15-bp insertion allele was associated with a 1.26-fold risk for HCC (95% CI=1.04-1.54, p=0.018). Moreover, significant differences were observed within HCC patients concerning genotypic frequencies of rs28381975 after stratifying by tumor stages and HBV infection. Computational modeling suggests that rs28381975 could disrupt the binding patterns of c-rel, a key subunit of nuclear factor-kappaB transcription factor. Further luciferase-based transient transfection assays revealed that rs28381975 can affect the promoter activity of PDCD6IP, indicating its possible functional significance. Taken together, our data suggest that common genetic variations in PDCD6IP may influence HCC risk, possibly through promoter activity-mediated regulation. Replication of our studies in other populations and further functional analysis will strengthen our understanding of this association.

Takahashi K, Kantarjian H, Pemmaraju N, et al.
Salvage therapy using FLT3 inhibitors may improve long-term outcome of relapsed or refractory AML in patients with FLT3-ITD.
Br J Haematol. 2013; 161(5):659-66 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
To determine the long-term efficacy of FLT3 inhibitors (FLT3i) in the salvage setting for relapsed and refractory (rel/ref) acute myeloid leukemia (AML) with FLT3 internal tandem duplication (AML FLT3-ITD), we conducted a retrospective study of 120 patients with rel/ref AML FLT3-ITD who received salvage therapy with either FLT3i-containing regimen (FLT3i group, N = 45) or conventional cytotoxic regimen (conventional group, N = 75). The median overall survival (OS) after the first salvage in the FLT3i group was 6·9 vs. 4·6 months in the conventional group (P = 0·17). The OS was better in the FLT3i group among patients with initial complete remission (CR) duration ≤12 months or with primary refractory disease (6·9 vs. 3·7 months; P < 0·01). The OS was better when FLT3i was combined with cytotoxic agents versus monotherapy (17 vs. 4·8 months; P = 0·017). Multivariate analysis revealed that the use of FLT3i was an independent predictor of OS (hazard ratio 0·58; 95% confidence interval, 0·38-0·88). Incorporating FLT3i into salvage strategies may improve long-term outcome of patients with AML FLT3-ITD. Prospective studies to validate this conclusion are warranted.

Nottingham LK, Yan CH, Yang X, et al.
Aberrant IKKα and IKKβ cooperatively activate NF-κB and induce EGFR/AP1 signaling to promote survival and migration of head and neck cancer.
Oncogene. 2014; 33(9):1135-47 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
The inhibitor-κB kinase-nuclear factor-κB (IKK-NF-κB) and epidermal growth factor receptor-activator protein-1 (EGFR-AP1) pathways are often co-activated and promote malignant behavior, but the underlying basis for this relationship is unclear. Resistance to inhibitors of IKKβ or EGFR is observed in head and neck squamous cell carcinomas (HNSCC). Here, we reveal that both IKKα and β contribute to nuclear activation of canonical and alternate NF-κB/REL family transcription factors, and overexpression of signal components that enhance co-activation of the EGFR-AP1 pathway. We observed that IKKα and IKKβ exhibit increased protein expression, nuclear localization, and phosphorylation in HNSCC tissues and cell lines. Individually, IKK activity varied among different cell lines, but overexpression of both IKKs induced the strongest NF-κB activation. Conversely, siRNA knock down of both IKKs significantly decreased nuclear localization and phosphorylation of canonical RELA and IκBα and alternative p52 and RELB subunits. Knock down of both IKKs more effectively inhibited NF-κB activation, broadly modulated gene expression and suppressed cell proliferation and migration. Global expression profiling revealed that NF-κB, cytokine, inflammatory response and growth factor signaling are among the top pathways and networks regulated by IKKs. Importantly, IKKα and IKKβ together promoted the expression and activity of transforming growth factor α, EGFR and AP1 transcription factors cJun, JunB and Fra1. Knock down of AP1 subunits individually decreased 8/15 (53%) of IKK-targeted genes sampled and similarly inhibited cell proliferation and migration. Mutations of NF-κB and AP1-binding sites abolished or decreased IKK-induced interleukin-8 (IL-8) promoter activity. Compounds such as wedelactone with dual IKK inhibitory activity and geldanomycins that block IKKα/β and EGFR pathways were more active than IKKβ-specific inhibitors in suppressing NF-κB activation and proliferation and inducing cell death. We conclude that IKKα and IKKβ cooperatively activate NF-κB and EGFR/AP1 networks of signaling pathways and contribute to the malignant phenotype and the intrinsic or acquired therapeutic resistance of HNSCC.

Aravindan S, Natarajan M, Herman TS, et al.
Molecular basis of 'hypoxic' breast cancer cell radio-sensitization: phytochemicals converge on radiation induced Rel signaling.
Radiat Oncol. 2013; 8:46 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
BACKGROUND: Heterogeneously distributed hypoxic areas are a characteristic property of locally advanced breast cancers (BCa) and generally associated with therapeutic resistance, metastases, and poor patient survival. About 50% of locally advanced BCa, where radiotherapy is less effective are suggested to be due to hypoxic regions. In this study, we investigated the potential of bioactive phytochemicals in radio-sensitizing hypoxic BCa cells.
METHODS: Hypoxic (O2-2.5%; N2-92.5%; CO2-5%) MCF-7 cells were exposed to 4 Gy radiation (IR) alone or after pretreatment with Curcumin (CUR), curcumin analog EF24, neem leaf extract (NLE), Genistein (GEN), Resveratrol (RES) or raspberry extract (RSE). The cells were examined for inhibition of NFκB activity, transcriptional modulation of 88 NFκB signaling pathway genes, activation and cellular localization of radio-responsive NFκB related mediators, eNos, Erk1/2, SOD2, Akt1/2/3, p50, p65, pIκBα, TNFα, Birc-1, -2, -5 and associated induction of cell death.
RESULTS: EMSA revealed that cells exposed to phytochemicals showed complete suppression of IR-induced NFκB. Relatively, cells exposed EF24 revealed a robust inhibition of IR-induced NFκB. QPCR profiling showed induced expression of 53 NFκB signaling pathway genes after IR. Conversely, 53, 50, 53, 53, 53 and 53 of IR-induced genes were inhibited with EF24, NLE, CUR, GEN, RES and RSE respectively. In addition, 25, 29, 24, 16, 11 and 21 of 35 IR-suppressed genes were further inhibited with EF24, NLE, CUR, GEN, RES and RSE respectively. Immunoblotting revealed a significant attenuating effect of IR-modulated radio-responsive eNos, Erk1/2, SOD2, Akt1/2/3, p50, p65, pIκBα, TNFα, Birc-1, -2 and -5 with EF24, NLE, CUR, GEN, RES or RSE. Annexin V-FITC staining showed a consistent and significant induction of IR-induced cell death with these phytochemicals. Notably, EF24 robustly conferred IR-induced cell death.
CONCLUSIONS: Together, these data identifies the potential hypoxic cell radio-sensitizers and further implies that the induced radio-sensitization may be exerted by selectively targeting IR-induced NFκB signaling.

Fontan L, Yang C, Kabaleeswaran V, et al.
MALT1 small molecule inhibitors specifically suppress ABC-DLBCL in vitro and in vivo.
Cancer Cell. 2012; 22(6):812-24 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
MALT1 cleavage activity is linked to the pathogenesis of activated B cell-like diffuse large B cell lymphoma (ABC-DLBCL), a chemoresistant form of DLBCL. We developed a MALT1 activity assay and identified chemically diverse MALT1 inhibitors. A selected lead compound, MI-2, featured direct binding to MALT1 and suppression of its protease function. MI-2 concentrated within human ABC-DLBCL cells and irreversibly inhibited cleavage of MALT1 substrates. This was accompanied by NF-κB reporter activity suppression, c-REL nuclear localization inhibition, and NF-κB target gene downregulation. Most notably, MI-2 was nontoxic to mice, and displayed selective activity against ABC-DLBCL cell lines in vitro and xenotransplanted ABC-DLBCL tumors in vivo. The compound was also effective against primary human non-germinal center B cell-like DLBCLs ex vivo.

Barton S, Hawkes EA, Wotherspoon A, Cunningham D
Are we ready to stratify treatment for diffuse large B-cell lymphoma using molecular hallmarks?
Oncologist. 2012; 17(12):1562-73 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
The division of the heterogeneous entity of diffuse large B-cell lymphoma (DLBCL) into the ontogenic phenotypes of germinal center B-cell-like (GCB) and activated B-cell-like (ABC) is optimally determined by gene expression profiling (GEP), although simpler immunohistochemistry (IHC) algorithms are alternatively being used. The cell-of-origin (COO) classification assists in prognostication and may be predictive of response to therapy. Mounting data suggests that IHC methods of classifying COO may be inaccurate. GEP categorization of COO is superior in defining prognostically and biologically distinct DLBCL subtypes, but current barriers to its widescale use include inaccessibility, cost, and lack of methodological standardization and prospective validation. The poorer prognosis of ABC-DLBCL is frequently associated with constitutive activity in the NF-κB pathway and aberrations in upstream or downstream regulators of this pathway. The molecular mechanisms underlying lymphomagenesis in GCB-DLBCL are arguably less well defined, but C-REL amplification and mutations in BCL-2 and EZH2 are common. New technologies, such as next-generation sequencing, are rapidly revealing novel pathogenic genetic aberrations, and DLBCL treatment strategies are increasingly being designed focusing on distinctive pathogenic drivers within ontogenic phenotypes. This review examines emerging molecular targets and novel therapeutic agents in DLBCL, and discusses whether stratifying therapy for DLBCL using molecular features is merited by current preclinical and clinical evidence.

Zhang NN, Sun QS, Chen Z, et al.
Homeostatic regulatory role of Pokemon in NF-κB signaling: stimulating both p65 and IκBα expression in human hepatocellular carcinoma cells.
Mol Cell Biochem. 2013; 372(1-2):57-64 [PubMed] Related Publications
NF-κB consists of p50, p65 (RelA), p52, c-Rel, and RelB, and among them p65 is a representative protein to investigate the regulation and function of this signaling. NF-κB integrates inflammation and carcinogenesis and regulates the expression of a variety of genes in response to immunity, inflammation, and apoptosis. IκBα acts as an inhibitor of NF-κB through forming an inactive NF-κB/IκBα complex. Pokemon is a ubiquitous transcription factor involved in different signaling pathways, playing a pivotal role in cell proliferation, anti-apoptosis, embryonic development, and maintenance. In this study, we found that p65 and IκBα are both novel regulatory targets of Pokemon. Ectopic expression of Pokemon in immortalized liver cells HL7702 enhanced p65 and IκBα expression, whereas silencing of Pokemon in hepatocellular carcinoma cells QGY7703 reduced cellular p65 levels. ChIP assay and targeted mutagenesis revealed that Pokemon directly binds to the element of -434 to -430 bp in p65 promoter and of -453 to -448 bp in IκBα promoter and stimulates luciferase reporter gene expression. Co-transfection of Pokemon with p65 or IκBα promoter-reporter notably enhanced their promoter activity. These data suggest that Pokemon activates the expression of both p65 and IκBα by sequence-specific binding to their promoters and plays a dual role in regulating NF-κB signaling.

Gillespie E, Leeman SE, Watts LA, et al.
Plasminogen activator inhibitor-1 is increased in colonic epithelial cells from patients with colitis-associated cancer.
J Crohns Colitis. 2013; 7(5):403-11 [PubMed] Related Publications
BACKGROUND: Patients with long-term ulcerative colitis are at risk for developing colorectal cancer.
METHODS: Archival formalin-fixed paraffin-embedded tissue from ulcerative colitis patients who underwent a colectomy for high-grade dysplasia or carcinoma was examined for changes in expression of plasminogen activator inhibitor-1 (PAI-1) as well as other mediators of inflammation-associated cancer. Epithelia from areas of colons that showed histologic evidence of carcinoma, high-grade dysplasia, and epithelia that were not dysplastic or malignant but did contain evidence of prior inflammation (quiescent colitis) was microdissected using laser capture microscopy. mRNA was extracted from the microdissected tissue and PCR array analysis was performed. To extend our findings, PAI-1 protein levels were determined using immunohistochemistry.
RESULTS: The mRNA expression of PAI-1 is increased 6-fold (p=0.02) when comparing the carcinoma group to the quiescent colitis group; increases were also observed in NFKB2, REL, SRC, and VEGFA. The protein levels of PAI-1 are increased by 50% (p<0.001) in high-grade dysplasia and by 60% (p<0.001) in carcinoma when compared to the quiescent colitis group.
CONCLUSIONS: The increase in PAI-1 in high-grade dysplasia and carcinoma suggests a functional role for PAI-1 in malignant transformation in colitis-associated cancer. PAI-1 could also prove a useful diagnostic marker to identify patients at risk for neoplasia and it may be a useful therapeutic target to treat colitis-associated cancer.

Flossbach L, Holzmann K, Mattfeldt T, et al.
High-resolution genomic profiling reveals clonal evolution and competition in gastrointestinal marginal zone B-cell lymphoma and its large cell variant.
Int J Cancer. 2013; 132(3):E116-27 [PubMed] Related Publications
We studied marginal zone B-cell lymphomas of the gastrointestinal tract including seven small cell lymphomas, eight large cell areas of composite lymphomas and 13 large cell variants using SNP array profiling. We found an increase of genomic complexity with lymphoma progression from small to large cytology, and identified gains of prominent (proto) oncogenes such as REL, BCL11A, ETS1, PTPN1, PTEN and KRAS which were found exclusively in the large cell variants. Copy numbers of ADAM3A, SCAPER and SIRPB1 were varying between the three different modes of presentation, hence suggestive for aberrations associated with progression from small to large cell lymphoma. The number of aberrations was slightly higher in the large cell part of composite lymphomas than in large cell lymphomas, suggesting that clonal selection takes place and that composite lymphomas are in a transition state. To further investigate this, we comparatively analyzed samples of two morphologically different regions of the same small cell tumor with a BIRC3-MALT1 translocation, as well as material acquired at two different time points from one composite lymphoma. We found genomic heterogeneity in both cases, supporting the theory of competing subclones in the evolution and progression of extranodal marginal zone B-cell lymphoma.

Macaire H, Riquet A, Moncollin V, et al.
Tax protein-induced expression of antiapoptotic Bfl-1 protein contributes to survival of human T-cell leukemia virus type 1 (HTLV-1)-infected T-cells.
J Biol Chem. 2012; 287(25):21357-70 [PubMed] Article available free on PMC after 14/11/2015 Related Publications
Human T lymphotropic virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia/lymphoma (ATLL). ATLL is a severe malignancy with no effective treatment. HTLV-1 regulatory proteins Tax and HTLV-1 basic leucine zipper factor (HBZ) play a major role in ATLL development, by interfering with cellular functions such as CD4(+) T-cell survival. In this study, we observed that the expression of Bfl-1, an antiapoptotic protein of the Bcl-2 family, is restricted to HTLV-1-infected T-cell lines and to T-cells expressing both Tax and HBZ proteins. We showed that Tax-induced bfl-1 transcription through the canonical NF-κB pathway. Moreover, we demonstrated that Tax cooperated with c-Jun or JunD, but not JunB, transcription factors of the AP-1 family to stimulate bfl-1 gene activation. By contrast, HBZ inhibited c-Jun-induced bfl-1 gene activation, whereas it increased JunD-induced bfl-1 gene activation. We identified one NF-κB, targeted by RelA, c-Rel, RelB, p105/p50, and p100/p52, and two AP-1, targeted by both c-Jun and JunD, binding sites in the bfl-1 promoter of T-cells expressing both Tax and HBZ. Analyzing the potential role of antiapoptotic Bcl-2 proteins in HTLV-1-infected T-cell survival, we demonstrated that these cells are differentially sensitive to silencing of Bfl-1, Bcl-x(L), and Bcl-2. Indeed, both Bfl-1 and Bcl-x(L) knockdowns decreased the survival of HTLV-1-infected T-cell lines, although no cell death was observed after Bcl-2 knockdown. Furthermore, we demonstrated that Bfl-1 knockdown sensitizes HTLV-1-infected T-cells to ABT-737 or etoposide treatment. Our results directly implicate Bfl-1 and Bcl-x(L) in HTLV-1-infected T-cell survival and suggest that both Bfl-1 and Bcl-x(L) represent potential therapeutic targets for ATLL treatment.

Miglino M, Colombo N, Grasso R, et al.
Nucleophosmin gene-based monitoring in de novo cytogenetically normal acute myeloid leukemia with nucleophosmin gene mutations: comparison with cytofluorimetric analysis and study of Wilms tumor gene 1 expression.
Leuk Lymphoma. 2012; 53(11):2214-7 [PubMed] Related Publications
We compared the clinical value of minimal residual disease (MRD) monitoring by cytofluorimetric methods, Wilms tumor gene 1 (WT1) expression and the study of nucleophosmin gene (NPM) mutations in a series of 26 patients with NPM-mutated de novo acute myeloid leukemia (NPM-AML) who achieved complete hematological remission after conventional chemotherapy. The relapse risk was significantly lower only in patients achieving a NPM molecular complete response (NPM mol-CR) and confirmed NPM mol-CR (non-detectable NPM mutations in two consecutive marrow samples). The disease-free survival (DFS) of patients achieving a < 4-log or ≥ 4-log reduction in NPM value after induction therapy was 12.6 % and 50%, respectively, at 36 months (p = 0.009). The attainment of a confirmed NPM-CR had a significant influence on overall survival (OS at 36 months was 64.3% and 11.9% in patients obtaining or not obtaining confirmed NPM-CR, respectively, p < 0.03). We confirm that NPM-molecular relapse (NPM-rel) is always followed by hematological relapse (H-rel), but longitudinal studies of NPM mutations may predict an impending H-rel earlier than flow cytometric- or WT1-based methods.

DiDonato JA, Mercurio F, Karin M
NF-κB and the link between inflammation and cancer.
Immunol Rev. 2012; 246(1):379-400 [PubMed] Related Publications
The nuclear factor-κB (NF-κB) transcription factor family has been considered the central mediator of the inflammatory process and a key participant in innate and adaptive immune responses. Coincident with the molecular cloning of NF-κB/RelA and identification of its kinship to the v-Rel oncogene, it was anticipated that NF-κB itself would be involved in cancer development. Oncogenic activating mutations in NF-κB genes are rare and have been identified only in some lymphoid malignancies, while most NF-κB activating mutations in lymphoid malignancies occur in upstream signaling components that feed into NF-κB. NF-κB activation is also prevalent in carcinomas, in which NF-κB activation is mainly driven by inflammatory cytokines within the tumor microenvironment. Importantly, however, in all malignancies, NF-κB acts in a cell type-specific manner: activating survival genes within cancer cells and inflammation-promoting genes in components of the tumor microenvironment. Yet, the complex biological functions of NF-κB have made its therapeutic targeting a challenge.

Gantke T, Sriskantharajah S, Sadowski M, Ley SC
IκB kinase regulation of the TPL-2/ERK MAPK pathway.
Immunol Rev. 2012; 246(1):168-82 [PubMed] Related Publications
Nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) activation play central roles in the induction of gene expression in innate immune cells following pathogen recognition. TPL-2 (tumor progression locus 2) is the MAP 3-kinase component of an ERK-1/2 (extracellular signal-regulated kinase 1/2) MAPK pathway activated by Toll-like receptor and tumor necrosis factor receptor family stimulation. In this review, we discuss results obtained from our laboratory and others that show that TPL-2 signaling function is directly controlled by the inhibitor of NF-κB (IκB) kinase (IKK) complex. Significantly, this means that IKK controls both NF-κB and ERK activation. TPL-2 is stoichiometrically complexed with the NF-κB inhibitory protein, NF-κB1 p105, and the ubiquitin-binding protein ABIN-2, both of which are required to maintain TPL-2 protein stability. Binding to p105 also prevents TPL-2 from phosphorylating MEK (MAPK/ERK kinase), its downstream target. Agonist stimulation releases TPL-2 from p105-inhibition by IKK-mediated phosphorylation of p105, which triggers degradation of p105 by the proteasome. This facilitates TPL-2 phosphorylation of MEK, in addition to liberating p105-associated Rel subunits to translocate into the nucleus. We also examine evidence that TPL-2 is critical for the induction of inflammation and may play a role in development and/or progression of certain types of cancer. Finally, we consider the potential of TPL-2 as an anti-inflammatory drug target for treatment of certain types of inflammatory disease and cancer.

Liu K, Feng T, Liu J, et al.
Silencing of the DEK gene induces apoptosis and senescence in CaSki cervical carcinoma cells via the up-regulation of NF-κB p65.
Biosci Rep. 2012; 32(3):323-32 [PubMed] Related Publications
The human DEK proto-oncogene has been found to play an important role in autoimmune disease, viral infection and human carcinogenesis. Although it is transcriptionally up-regulated in cervical cancer, its intracellular function and regulation is still unexplored. In the present study, DEK and IκBα [inhibitor of NF-κB (nuclear factor κB) α] shRNAs (short hairpin RNAs) were constructed and transfected into CaSki cells using Lipofectamine™. The stable cell line CaSki-DEK was obtained after G418 selection. CaSki-IκB cells were observed at 48 h after psiRNA-IκB transfection. The inhibitory efficiency of shRNAs were detected by RT (reverse transcription)-PCR and Western blot analysis. The proliferation activity of cells were measured using an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay, cell apoptosis was measured using an Annexin V/PI (propidium iodide) kit, the cell cycle was analysed by flow cytometry and cell senescence was detected using senescence β-galactosidase staining. The intracellular expression of NF-κB p65 protein was studied by cytochemistry. The expression levels of NF-κB p65, p50, c-Rel, IκBα and phospho-IκBα protein were analysed by immunoblotting in whole-cell lysates, cytosolic fractions and nuclear extracts. The protein expression and activity of p38 and JNK (c-Jun N-terminal kinase) were also assayed. In addition, the NF-κB p65 DNA-binding activity was measured by ELISA. Following the silencing of DEK and IκBα, cell proliferation was inhibited, apoptosis was increased, the cell cycle was blocked in the G0/G1-phase with a corresponding decrease in the G2/M-phase, and cell senescence was induced. All of these effects may be related to the up-regulation of NF-κB p65 expression and its nuclear translocation.

Santacana M, Yeramian A, Velasco A, et al.
Immunohistochemical features of post-radiation vaginal recurrences of endometrioid carcinomas of the endometrium: role for proteins involved in resistance to apoptosis and hypoxia.
Histopathology. 2012; 60(3):460-71 [PubMed] Related Publications
AIMS: Endometrioid carcinoma of the endometrium (EEC) is treated with surgery and radiotherapy. Post-radiation recurrences are associated with increased risk of metastases. Comparison of the expression of genes important in the development and progression of EEC, and others involved in resistance to apoptosis and hypoxia and adaptation to radiation, was performed between post-radiation vaginal recurrences (PVRs) and primary EECs. We tried to reproduce the results by exposing an EEC cell line to hypoxia and radiation.
METHODS AND RESULTS: Immunohistochemistry and tissue microarrays were used to compare 24 PVRs with 82 primary EECs. PVRs exhibited increased expression of p53 (P < 0.0001), cytoplasmic FLICE-inhibitory protein (FLIP) (P < 0.0001), and Ki67 (P < 0.0001), and nuclear staining for FLIP, nuclear factor kappaB (NF-κB) family members (p50, P < 0.0001; c-Rel, P = 0.0077; RelB, P = 0.0157), and β-catenin (P = 0.0001). Differences regarding p50, hypoxia-inducible factor 1α (HIF-1α), and cytoplasmic FLIP were statistically significant when PVRs and primary EECs were matched for histological grade. Exposure of the EEC cell line to hypoxia induced nuclear expression of β-catenin, FLIP, and HIF-1α, as well as increased NF-κB activity. No changes in FLIP, HIF-1α or NF-κB were seen when cells were exposed to radiation. Nuclear expression of β-catenin was seen at 3 Gy, but not at 1 Gy.
CONCLUSIONS: Genes involved in resistance to hypoxia are expressed in PVRs, and may play a role in the development of post-radiation recurrences.

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