Genomic Studies of Multiple Myeloma Reveal an Association between X Chromosome Alterations and Genomic Profile Complexity.
Sticca, Tiberio ; CABERG, Jean-Hubert ; Wenric, Stéphane et al
in Genes, Chromosomes & Cancer (2017)
The genomic profile of multiple myeloma (MM) has prognostic value by dividing patients into a good prognosis hyperdiploid group and a bad prognosis non-hyperdiploid group with a higher incidence of IgH ... [more ▼]
The genomic profile of multiple myeloma (MM) has prognostic value by dividing patients into a good prognosis hyperdiploid group and a bad prognosis non-hyperdiploid group with a higher incidence of IgH translocations. This classification, however, is inadequate and many other parameters like mutations, epigenetic modifications and genomic heterogeneity may influence the prognosis. We performed a genomic study by array-based comparative genomic hybridization (aCGH) on a cohort of 162 patients to evaluate the frequency of genomic gains and losses. We identified a high frequency of X chromosome alterations leading to partial Xq duplication, often associated with Xi deletion in female patients. This partial X duplication could be a cytogenetic marker of aneuploidy as it is correlated with a high number of chromosomal breakages. Patient with high level of chromosomal breakage had reduced survival regardless the region implicated. A higher transcriptional level was shown for genes with potential implication in cancer and located in this altered region. Among these genes, IKBKG and IRAK1 are members of the NFKB pathway which plays an important role in MM and is a target for specific treatments. [less ▲]Detailed reference viewed: 25 (4 ULg)
MicroRNAs and Inflammation in Colorectal Cancer.
Josse, Claire ; Bours, Vincent
in Slaby, Ondrej; Calin, George A. (Eds.) Non-coding RNAs in Colorectal Cancer (2016)
Colorectal cancers (CRC) are known to be related to inflammatory conditions, and inflammatory bowel diseases increase the relative risk for developing CRC. The use of anti-inflammatory drugs prevents the ... [more ▼]
Colorectal cancers (CRC) are known to be related to inflammatory conditions, and inflammatory bowel diseases increase the relative risk for developing CRC. The use of anti-inflammatory drugs prevents the development of colorectal cancer.Several molecular mediators are connecting the pathways that are involved in inflammatory conditions and in carcinogenesis. By the way these pathways are tightly interwoven, with the consequence that a deregulation at the level of any of these molecular mediators can affect the others.MiRNAs are demonstrated to be deregulated in inflammatory bowel diseases and in colorectal cancer. Moreover, they target several molecular mediators that connect inflammation to cancer, and they are thus implicated in the route from inflammation to colorectal cancer.This chapter will focus on the miRNAs that are jointly deregulated in inflammatory bowel disease and in colorectal cancer. Their role on the regulation of the molecular mediators and pathways that link inflammation to cancer will be described. [less ▲]Detailed reference viewed: 16 (2 ULg)
Circulating microRNA-based screening tool for breast cancer
Freres, Pierre ; Wenric, Stéphane ; et al
in Oncotarget (2015)
Circulating microRNAs (miRNAs) are increasingly recognized as powerful biomarkers in several pathologies, including breast cancer. Here, their plasmatic levels were measured to be used as an alternative ... [more ▼]
Circulating microRNAs (miRNAs) are increasingly recognized as powerful biomarkers in several pathologies, including breast cancer. Here, their plasmatic levels were measured to be used as an alternative screening procedure to mammography for breast cancer diagnosis. A plasma miRNA profile was determined by RT-qPCR in a cohort of 378 women. A diagnostic model was designed based on the expression of 8 miRNAs measured first in a profiling cohort composed of 41 primary breast cancers and 45 controls, and further validated in diverse cohorts composed of 108 primary breast cancers, 88 controls, 35 breast cancers in remission, 31 metastatic breast cancers and 30 gynecologic tumors. A receiver operating characteristic curve derived from the 8-miRNA random forest based diagnostic tool exhibited an area under the curve of 0.81. The accuracy of the diagnostic tool remained unchanged considering age and tumor stage. The miRNA signature correctly identified patients with metastatic breast cancer. The use of the classification model on cohorts of patients with breast cancers in remission and with gynecologic cancers yielded prediction distributions similar to that of the control group. Using a multivariate supervised learning method and a set of 8 circulating miRNAs, we designed an accurate, minimally invasive screening tool for breast cancer. [less ▲]Detailed reference viewed: 73 (25 ULg)
BRCA1 germline mutation and glioblastoma development: report of cases
Boukerroucha, Meriem ; Josse, Claire ; SEGERS, Karin et al
in BMC Cancer (2015), 15
Background Germline mutations in breast cancer susceptibility gene 1 (BRCA1) increase the risk of breast and ovarian cancers. However, no association between BRCA1 germline mutation and glioblastoma ... [more ▼]
Background Germline mutations in breast cancer susceptibility gene 1 (BRCA1) increase the risk of breast and ovarian cancers. However, no association between BRCA1 germline mutation and glioblastoma malignancy has ever been highlighted. Here we report two cases of BRCA1 mutated patients who developed a glioblastoma (GBM). Cases presentation Two patients diagnosed with triple negative breast cancer (TNBC) were screened for BRCA1 germline mutation. They both carried a pathogenic mutation introducing a premature STOP codon in the exon 11 of the BRCA1 gene. Few years later, both patients developed a glioblastoma and a second breast cancer. In an attempt to clarify the role played by a mutated BRCA1 allele in the GBM development, we investigated the BRCA1 mRNA and protein expression in breast and glioblastoma tumours for both patients. The promoter methylation status of this gene was also tested by methylation specific PCR as BRCA1 expression is also known to be lost by this mechanism in some sporadic breast cancers. Conclusion Our data show that BRCA1 expression is maintained in glioblastoma at the protein and the mRNA levels, suggesting that loss of heterozygosity (LOH) did not occur in these cases. The protein expression is tenfold higher in the glioblastoma of patient 1 than in her first breast carcinoma, and twice higher in patient 2. In agreement with the high protein expression level in the GBM, BRCA1 promoter methylation was not observed in these tumours. In these two cases, despite of a BRCA1 pathogenic germline mutation, the tumour-suppressor protein expression is maintained in GBM, suggesting that the BRCA1 mutation is not instrumental for the GBM development. [less ▲]Detailed reference viewed: 38 (7 ULg)
Evaluation of BRCA1-related molecular features and microRNAs as prognostic factors for triple negative breast cancers.
Boukerroucha, Meriem ; Josse, Claire ; El Guendi, Sonia et al
in BMC cancer (2015), 15(1), 755
BACKGROUND: The BRCA1 gene plays a key role in triple negative breast cancers (TNBCs), in which its expression can be lost by multiple mechanisms: germinal mutation followed by deletion of the second ... [more ▼]
BACKGROUND: The BRCA1 gene plays a key role in triple negative breast cancers (TNBCs), in which its expression can be lost by multiple mechanisms: germinal mutation followed by deletion of the second allele; negative regulation by promoter methylation; or miRNA-mediated silencing. This study aimed to establish a correlation among the BRCA1-related molecular parameters, tumor characteristics and clinical follow-up of patients to find new prognostic factors. METHODS: BRCA1 protein and mRNA expression was quantified in situ in the TNBCs of 69 patients. BRCA1 promoter methylation status was checked, as well as cytokeratin 5/6 expression. Maintenance of expressed BRCA1 protein interaction with BARD1 was quantified, as a marker of BRCA1 functionality, and the tumor expression profiles of 27 microRNAs were determined. RESULTS: miR-548c-5p was emphasized as a new independent prognostic factor in TNBC. A combination of the tumoral expression of miR-548c and three other known prognostic parameters (tumor size, lymph node invasion and CK 5/6 expression status) allowed for relapse prediction by logistic regression with an area under the curve (AUC) = 0.96. BRCA1 mRNA and protein in situ expression, as well as the amount of BRCA1 ligated to BARD1 in the tumor, lacked any associations with patient outcomes, likely due to high intratumoral heterogeneity, and thus could not be used for clinical purposes. CONCLUSIONS: In situ BRCA1-related expression parameters could be used for clinical purposes at the time of diagnosis. In contrast, miR-548c-5p showed a promising potential as a prognostic factor in TNBC. [less ▲]Detailed reference viewed: 40 (10 ULg)
Endothelial exosomes contribute to the antitumor response during breast cancer neoadjuvant chemotherapy via microRNA transfer.
Bovy, Nicolas ; Blomme, Benoît ; Freres, Pierre et al
in Oncotarget (2015)
The interaction between tumor cells and their microenvironment is an essential aspect of tumor development. Therefore, understanding how this microenvironment communicates with tumor cells is crucial for ... [more ▼]
The interaction between tumor cells and their microenvironment is an essential aspect of tumor development. Therefore, understanding how this microenvironment communicates with tumor cells is crucial for the development of new anti-cancer therapies. MicroRNAs (miRNAs) are small non-coding RNAs that inhibit gene expression. They are secreted into the extracellular medium in vesicles called exosomes, which allow communication between cells via the transfer of their cargo. Consequently, we hypothesized that circulating endothelial miRNAs could be transferred to tumor cells and modify their phenotype. Using exogenous miRNA, we demonstrated that endothelial cells can transfer miRNA to tumor cells via exosomes. Using miRNA profiling, we identified miR-503, which exhibited downregulated levels in exosomes released from endothelial cells cultured under tumoral conditions. The modulation of miR-503 in breast cancer cells altered their proliferative and invasive capacities. We then identified two targets of miR-503, CCND2 and CCND3. Moreover, we measured increased plasmatic miR-503 in breast cancer patients after neoadjuvant chemotherapy, which could be partly due to increased miRNA secretion by endothelial cells. Taken together, our data are the first to reveal the involvement of the endothelium in the modulation of tumor development via the secretion of circulating miR-503 in response to chemotherapy treatment. [less ▲]Detailed reference viewed: 269 (45 ULg)
Cancer du sein : de la thérapie ciblée à la médecine personnalisée
JERUSALEM, Guy ; COLLIGNON, Joëlle ; Josse, Claire et al
in Revue Médicale de Liège (2015), 70(5-6), 269-276
Dans cet article, les auteurs passent en revue les grands principes de prise en charge du traitement systémique du cancer du sein et posent la question suivante : jusqu'où réellement aujourd'hui ce ... [more ▼]
Dans cet article, les auteurs passent en revue les grands principes de prise en charge du traitement systémique du cancer du sein et posent la question suivante : jusqu'où réellement aujourd'hui ce traitement est-il individualisé ? Les nouvelles technologies permettent une analyse détaillée des anomalies génomiques au niveau des cellules cancéreuses. Malheureusement, nous n'avons pas encore compris comment utiliser au mieux ces données au bénéfice du patient. La majorité des modifications du génome sont des évènements relativement rares compliquant le développement de nouveaux médicaments dans le cadre d'une médecine de précision. De plus, les tumeurs présentent une grande hétérogénéité temporelle et spatiale dont il faudra tenir compte lors de ce développement. Une collaboration internationale intensive est en cours pour tenter de confirmer que la médecine de précision permet d'optimiser les résultats du traitement systémique dans le cancer du sein. [less ▲]Detailed reference viewed: 180 (19 ULg)
Mutation of the iron-sulfur cluster assembly gene IBA57 causes fatal infantile leukodystrophy.
DEBRAY, François-Guillaume ; ; et al
in Journal of inherited metabolic disease (2015)
Leukodystrophies are a heterogeneous group of severe genetic neurodegenerative disorders. A multiple mitochondrial dysfunctions syndrome was found in an infant presenting with a progressive ... [more ▼]
Leukodystrophies are a heterogeneous group of severe genetic neurodegenerative disorders. A multiple mitochondrial dysfunctions syndrome was found in an infant presenting with a progressive leukoencephalopathy. Homozygosity mapping, whole exome sequencing, and functional studies were used to define the underlying molecular defect. Respiratory chain studies in skeletal muscle isolated from the proband revealed a combined deficiency of complexes I and II. In addition, western blotting indicated lack of protein lipoylation. The combination of these findings was suggestive for a defect in the iron-sulfur (Fe/S) protein assembly pathway. SNP array identified loss of heterozygosity in large chromosomal regions, covering the NFU1 and BOLA3, and the IBA57 and ABCB10 candidate genes, in 2p15-p11.2 and 1q31.1-q42.13, respectively. A homozygous c.436C > T (p.Arg146Trp) variant was detected in IBA57 using whole exome sequencing. Complementation studies in a HeLa cell line depleted for IBA57 showed that the mutant protein with the semi-conservative amino acid exchange was unable to restore the biochemical phenotype indicating a loss-of-function mutation of IBA57. In conclusion, defects in the Fe/S protein assembly gene IBA57 can cause autosomal recessive neurodegeneration associated with progressive leukodystrophy and fatal outcome at young age. In the affected patient, the biochemical phenotype was characterized by a defect in the respiratory chain complexes I and II and a decrease in mitochondrial protein lipoylation, both resulting from impaired assembly of Fe/S clusters. [less ▲]Detailed reference viewed: 35 (9 ULg)
Neoadjuvant chemotherapy in breast cancer induces miR-34a and miR-122 expression
FRERES, Pierre ; JOSSE, Claire ; Bovy, Nicolas et al
in Journal of Cellular Physiology (2014)
Circulating microRNAs (miRNAs) have been extensively studied in cancer as biomarkers but little is known regarding the influence of anti-cancer drugs on their expression levels. In this article, we ... [more ▼]
Circulating microRNAs (miRNAs) have been extensively studied in cancer as biomarkers but little is known regarding the influence of anti-cancer drugs on their expression levels. In this article, we describe the modifications of circulating miRNAs profile after neoadjuvant chemotherapy (NAC) for breast cancer. The expression of 188 circulating miRNAs was assessed in the plasma of 25 patients before and after NAC by RT-qPCR. Two miRNAs, miR- 34a and miR-122, that were significantly increased after NAC, were measured in tumor tissue before and after chemotherapy in 7 patients with pathological partial response (pPR) to NAC. These 2 chemotherapy-induced miRNAs were further studied in the plasma of 22 patients with adjuvant chemotherapy (AC) as well as in 12 patients who did not receive any chemotherapy. Twenty-five plasma miRNAs were modified by NAC. Among these miRNAs, miR-34a and miR-122 were highly upregulated, notably in pPR patients with aggressive breast cancer. Furthermore, miR-34a level was elevated in the remaining tumor tissue after NAC treatment. Studying the kinetics of circulating miR-34a and miR-122 expression during NAC revealed that their levels were especially increased after anthracycline-based chemotherapy. Comparisons of the plasma miRNA profiles after NAC and AC suggested that chemotherapy-induced miRNAs originated from both tumoral and non-tumoral compartments. This study is the first to demonstrate that NAC specifically induces miRNA expression in plasma and tumor tissue, which might be involved in the anti-tumor effects of chemotherapy in breast cancer patients. [less ▲]Detailed reference viewed: 88 (32 ULg)
Identification of a microRNA landscape targeting the PI3K/Akt signaling pathway in inflammation-induced colorectal carcinogenesis
JOSSE, Claire ; Bouznad, Nassim ; Geurts, Pierre et al
in American Journal of Physiology - Gastrointestinal and Liver Physiology (2014), 306
Inflammation can contribute to tumor formation; however, markers that predict progression are still lacking. In the present study, the well-established azoxymethane (AOM)/dextran sulfate sodium (DSS ... [more ▼]
Inflammation can contribute to tumor formation; however, markers that predict progression are still lacking. In the present study, the well-established azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced mouse model of colitis-associated cancer was used to analyze microRNA (miRNA) modulation accompanying inflammation-induced tumor development and to determine whether inflammation-triggered miRNA alterations affect the expression of genes or pathways involved in cancer. A miRNA microarray experiment was performed to establish miRNA expression profiles in mouse colon at early and late time points during inflammation and/or tumor growth. Chronic inflammation and carcinogenesis were associated with distinct changes in miRNA expression. Nevertheless, prediction algorithms of miRNA-mRNA interactions and computational analyses based on ranked miRNA lists consistently identified putative target genes that play essential roles in tumor growth or that belong to key carcinogenesis-related signaling pathways. We identified PI3K/Akt and the insulin growth factor-1 (IGF-1) as major pathways being affected in the AOM/DSS model. DSS-induced chronic inflammation downregulates miR-133a and miR-143/145, which is reportedly associated with human colorectal cancer and PI3K/Akt activation. Accordingly, conditioned medium from inflammatory cells decreases the expression of these miRNA in colorectal adenocarcinoma Caco-2 cells. Overexpression of miR-223, one of the main miRNA showing strong upregulation during AOM/DSS tumor growth, inhibited Akt phosphorylation and IGF-1R expression in these cells. Cell sorting from mouse colons delineated distinct miRNA expression patterns in epithelial and myeloid cells during the periods preceding and spanning tumor growth. Hence, cell-type-specific miRNA dysregulation and subsequent PI3K/Akt activation may be involved in the transition from intestinal inflammation to cancer. [less ▲]Detailed reference viewed: 105 (20 ULg)
A miRNA expression based diagnostic tool for breast cancer using random forests
Wenric, Stéphane ; Freres, Pierre ; Josse, Claire et al
Poster (2013, December 09)
We developed a novel diagnostic tool for breast cancer using circulating miRNA expression levels as features of a supervised machine learning problem. We showed very good results on an independent ... [more ▼]
We developed a novel diagnostic tool for breast cancer using circulating miRNA expression levels as features of a supervised machine learning problem. We showed very good results on an independent validation cohort. [less ▲]Detailed reference viewed: 34 (9 ULg)
Exome sequencing of tumors: relevance in copy-number alteration (CNA) analysis and fixed tissue samples.
Wenric, Stéphane ; JOSSE, Claire ; Fasquelle, Corinne et al
Poster (2013, March 15)
Genomic DNA has been extracted from both cryopreserved and formalin-fixed paraffin-embedded forms of 2 different tumor samples (triple negative, and Her2+). Exome sequencing has been performed on all 4 ... [more ▼]
Genomic DNA has been extracted from both cryopreserved and formalin-fixed paraffin-embedded forms of 2 different tumor samples (triple negative, and Her2+). Exome sequencing has been performed on all 4 forms, as well as SNP and CNA detection. A comparison of the various metrics and results related to the sequencing, mapping, and variants detection has been done, outlining what can, and can’t be done with exome data sequenced from cryopreserved and FFPE tissue. [less ▲]Detailed reference viewed: 32 (12 ULg)
Aspects moléculaires du cancer du sein triple négatif et les implications thérapeutiques
COLLIGNON, Joëlle ; Struman, Ingrid ; Tabruyn, Sébastien et al
in Revue Médicale de Liège (2011), 66(5-6), 393-396Detailed reference viewed: 204 (39 ULg)
Systematic chromosomal aberrations found in murine bone marrow-derived mesenchymal stem cells.
Josse, Claire ; ; Niessen, Neville-Andrew et al
in Stem Cells & Development (2010), 19(8), 1167-1173
Mesenchymal stem cells (MSCs) are studied as a cellular source for the treatment of various diseases. In this work, we isolated and cultivated murine bone marrow-derived MSCs. After a first observation of ... [more ▼]
Mesenchymal stem cells (MSCs) are studied as a cellular source for the treatment of various diseases. In this work, we isolated and cultivated murine bone marrow-derived MSCs. After a first observation of a solid tumour in a mouse injected with these cells, we systematically explored their chromosomal stability. We observed in all the cytogenetically analysed cases gross chromosomal alterations every time the MSCs went through the senescence crisis while the lymphocytes from the same animals showed a normal chromosome count. This observation was confirmed in different mouse strains, with different culture protocols, and even in short-term cultures after an hematopoietic cell negative immunodepletion performed in order to accelerate the isolation procedure. Therefore, we conclude that murine MSCs display high chromosomal instability, can generate tumours, and that care must be taken before using them for the evaluation of MSC therapeutic potential. [less ▲]Detailed reference viewed: 65 (19 ULg)
The umbilical cord matrix is a better source of mesenchymal stem cells (MSC) than the umbilical cord blood.
Zeddou, Mustapha ; Briquet, Alexandra ; Relic, Biserka et al
in Cell Biology International (2010), 34(7), 693-701
Many studies have drawn attention to the emerging role of MSC (mesenchymal stem cells) as a promising population supporting new clinical concepts in cellular therapy. However, the sources from which these ... [more ▼]
Many studies have drawn attention to the emerging role of MSC (mesenchymal stem cells) as a promising population supporting new clinical concepts in cellular therapy. However, the sources from which these cells can be isolated are still under discussion. Whereas BM (bone marrow) is presented as the main source of MSC, despite the invasive procedure related to this source, the possibility of isolating sufficient numbers of these cells from UCB (umbilical cord blood) remains controversial. Here, we present the results of experiments aimed at isolating MSC from UCB, BM and UCM (umbilical cord matrix) using different methods of isolation and various culture media that summarize the main procedures and criteria reported in the literature. Whereas isolation of MSC were successful from BM (10:10) and (UCM) (8:8), only one cord blood sample (1:15) gave rise to MSC using various culture media [DMEM (Dulbecco's modified Eagle's medium) +5% platelet lysate, DMEM+10% FBS (fetal bovine serum), DMEM+10% human UCB serum, MSCGM] and different isolation methods [plastic adherence of total MNC (mononuclear cells), CD3+/CD19+/CD14+/CD38+-depleted MNC and CD133+- or LNGFR+-enriched MNC]. MSC from UCM and BM were able to differentiate into adipocytes, osteocytes and hepatocytes. The expansion potential was highest for MSC from UCM. The two cell populations had CD90+/CD73+/CD105+ phenotype with the additional expression of SSEA4 and LNGFR for BM MSC. These results clearly exclude UCB from the list of MSC sources for clinical use and propose instead UCM as a rich, non-invasive and abundant source of MSC. [less ▲]Detailed reference viewed: 88 (25 ULg)
Oligodendrocyte development and myelinogenesis are not impaired by high concentrations of phenylalanine or its metabolites.
; ; et al
in Journal of Inherited Metabolic Disease (2010), 33(2), 113-20
Phenylketonuria (PKU) is a metabolic genetic disease characterized by deficient phenylalanine hydroxylase (PAH) enzymatic activity. Brain hypomyelination has been reported in untreated patients, but its ... [more ▼]
Phenylketonuria (PKU) is a metabolic genetic disease characterized by deficient phenylalanine hydroxylase (PAH) enzymatic activity. Brain hypomyelination has been reported in untreated patients, but its mechanism remains unclear. We therefore investigated the influence of phenylalanine (Phe), phenylpyruvate (PP), and phenylacetate (PA) on oligodendrocytes. We first showed in a mouse model of PKU that the number of oligodendrocytes is not different in corpus callosum sections from adult mutants or from control brains. Then, using enriched oligodendroglial cultures, we detected no cytotoxic effect of high concentrations of Phe, PP, or PA. Finally, we analyzed the impact of Phe, PP, and PA on the myelination process in myelinating cocultures using both an in vitro index of myelination, based on activation of the myelin basic protein (MBP) promoter, and the direct quantification of myelin sheaths by both optical measurement and a bioinformatics method. None of these parameters was affected by the increased levels of Phe or its derivatives. Taken together, our data demonstrate that high levels of Phe, such as in PKU, are unlikely to directly induce brain hypomyelination, suggesting involvement of alternative mechanisms in this myelination defect. [less ▲]Detailed reference viewed: 66 (8 ULg)
Changes in function of iron-loaded alveolar macrophages after in vivo administration of desferrioxamine and/or chloroquine.
; Josse, Claire ; Piette, Jacques et al
in Journal of Inorganic Biochemistry (2003), 94(1-2), 36-42
Both desferrioxamine (DFO) and chloroquine can significantly reduce hepatic iron in experimental animals with iron overload by chelating iron from the low-molecular-weight pool or decreasing iron uptake ... [more ▼]
Both desferrioxamine (DFO) and chloroquine can significantly reduce hepatic iron in experimental animals with iron overload by chelating iron from the low-molecular-weight pool or decreasing iron uptake by the transferrin-transferrin receptor cycle, respectively. However, no previous studies have investigated whether combination therapy of these two drugs would further decrease the tissue iron overload as well as iron-induced toxicity. Chloroquine administration, 15 mg/kg, 5x/week, to rats during the iron loading regime, 10 mg/kg, 3x/week for 4 weeks, significantly decreased both hepatic (54%) and macrophage iron content (24%). However when administered in combination with desferrioxamine, 10 mg/kg, 3x/week for 2 weeks at the cessation of iron loading, no further reduction of hepatic iron content was noted while the iron content of the macrophages significantly increased, possibly indicating the flux of ferrioxamine through these cells. Further studies are warranted to investigate the speciation of iron within these macrophages. Macrophages isolated from chloroquine-treated iron loaded rats showed a reduction in latent NFkappaB activation and a significant increase in lipopolysaccharide-stimulated nitrite release by comparison to these parameters in iron loaded macrophages. Co-administration of chloroquine and desferrioxamine normalised the latent activity of NFkappaB to that of control macrophages as well as increasing LPS-stimulated NO release towards control values. However, DFO alone did not have any significant effect upon either of these parameters. Such results may have important relevance for the reduced immune function of iron loaded macrophages isolated from thalassaemia patients receiving chelation therapy and their propensity to increased infection. [less ▲]Detailed reference viewed: 10 (0 ULg)
Importance of post-transcriptional regulation of chemokine genes by oxidative stress.
JOSSE, Claire ; ; et al
in Biochemical Journal (2001), 360(Pt 2), 321-33
The transcription factor, nuclear factor kappa B (NF-kappa B), is activated by various stimuli including cytokines, radiation, viruses and oxidative stress. Here we show that, although induction with H(2 ... [more ▼]
The transcription factor, nuclear factor kappa B (NF-kappa B), is activated by various stimuli including cytokines, radiation, viruses and oxidative stress. Here we show that, although induction with H(2)O(2) gives rise to NF-kappa B nuclear translocation in both lymphocyte (CEM) and monocyte (U937) cells, it leads only to the production of mRNA species encoding interleukin-8 (IL-8) and macrophage inflammatory protein 1 alpha in U937 cells. Under similar conditions these mRNA species are not observed in CEM cells. With the use of a transient transfection assay of U937 cells transfected with reporter constructs of the IL-8 promoter and subsequently treated with H(2)O(2), we show that (1) IL-8-promoter-driven transcription is stimulated in both U937 and CEM cells and (2) the NF-kappa B site is crucial for activation because its deletion abolishes activation by H(2)O(2). The production of IL-8 mRNA in U937 cells is inhibited by the NF-kappa B inhibitors clasto-lactacystin-beta-lactone and E-64D (l-3-trans-ethoxycarbonyloxirane-2-carbonyl-L-leucine-3-methyl amide) but requires protein synthesis de novo. Moreover, inhibition of the p38 mitogen-activated protein kinase also decreases the IL-8 mRNA up-regulation mediated by H(2)O(2). Taken together, these results show the importance of post-transcriptional events controlled by a p38-dependent pathway in the production of IL-8 mRNA in U937. The much lower activation of p38 in CEM cells in response to H(2)O(2) could explain the lack of stabilization of IL-8 mRNA in these cells. [less ▲]Detailed reference viewed: 15 (2 ULg)
Impairment of mitochondrial functions abolishes NF-kappaB activation by an oxidative stress
Josse, Claire ; Legrand-Poels, Sylvie ; et al
in Free Radical Biology & Medicine (1998)Detailed reference viewed: 5 (0 ULg)