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  • 1
    Abstract: Chronic lymphocytic leukemia is a malignancy of mature B cells that strongly depend on microenvironmental factors and their deprivation has been identified as promising treatment approach for this incurable disease. Cytokine array screening of 247 chronic lymphocytic leukemia serum samples revealed elevated levels of TNF receptor-1 which were associated with poor clinical outcome. We detected a microenvironment-induced expression of TNF receptor-1 in chronic lymphocytic leukemia cells in vitro and aberrantly high expression of this receptor in proliferation centers of patients' lymph nodes. Stimulation of TNF receptor-1 with TNF-alpha enhanced NFkappaB activity and viability of chronic lymphocytic leukemia cells which was inhibited by wogonin. Therapeutic effects of wogonin were analyzed in mice after adoptive transfer of Em-TCL1 leukemic cells. Wogonin treatment prevented leukemia development when given early after transplantation. Treatment of full-blown leukemia resulted in loss of TNF receptor-1 on chronic lymphocytic leukemia cells and their mobilization to blood. Targeting TNF receptor-1 signaling is therefore proposed for treatment of chronic lymphocytic leukemia.
    Type of Publication: Journal article epub ahead of print
    PubMed ID: 29326123
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  • 2
    Keywords: CANCER ; Germany ; QUANTIFICATION ; TOOL ; RISK ; GENE ; SAMPLE ; SAMPLES ; TUMORS ; PATIENT ; DNA ; RISK-FACTORS ; MUTATION ; risk factors ; leukemia ; DNA methylation ; RISK FACTOR ; DERIVATIVES ; PARAMETERS ; FLUORESCENCE ; CYTOSINE METHYLATION ; CD38 EXPRESSION ; HYPERMETHYLATION ; 5-METHYLCYTOSINE CONTENT ; TUMORIGENESIS ; HEAVY ; chronic lymphocytic leukemia ; MUTATION STATUS ; 5-methylcytosine ; CPG ISLANDS ; capillary electrophoresis - laser induced fluorescence ; CAPILLARY-ELECTROPHORESIS ; GENOMIC HYPOMETHYLATION ; immunoglobulin variable heavy chain gene homology
    Abstract: Changes in the genomic DNA methylation level have been found to be closely associated with tumorigenesis. In order to analyze the relation of aberrant DNA methylation to clinical and biological risk factors, we have determined the cytosine methylation level of 81 patients diagnosed with chronic lymphocytic leukemia (CLL). The analysis was based on DNA hydrolysis followed by derivatization of the 2'-desoxyribonucleoside-3'-monophosphates with BODIPY FL EDA. Derivatives were separated by micellar electrokinetic chromatography, and laser-induced fluorescence was used for detection. We analyzed potential correlations between DNA methylation levels and numerous patient parameters, including clinical observations and biological data. As a result, we observed a significant correlation with the immunoglobulin variable heavy chain gene (VH) mutation status. This factor has been repeatedly proposed as a reliable prognostic marker for CLL, which suggests that the methylation level might be a valuable factor in determining the prognostic outcome of CLL. We are now in the process of refining our method to broaden its application potential. In this context, we show here that the oxidation of the fluorescence marker in the samples and the evaporation of methanol in the electrolytes can be prevented by a film of paraffin oil. In summary, our results thus establish capillary electrophoresis as a valuable tool for analyzing the DNA methylation status of clinical samples
    Type of Publication: Journal article published
    PubMed ID: 15188237
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  • 3
    Keywords: CELLS ; EXPRESSION ; SURVIVAL ; Germany ; GENE ; GENE-EXPRESSION ; GENES ; PROTEIN ; transcription ; PATIENT ; MECHANISM ; FAMILY ; TRANSCRIPTION FACTOR ; chromosome ; DELETION ; LYMPHOMA ; gene expression ; DISRUPTION ; UP-REGULATION ; MUTATION ; leukemia ; DELETIONS ; inactivation ; TUMOR-SUPPRESSOR GENE ; REGION ; B-CELLS ; point mutation ; TRANSCRIPTS ; molecular ; TUMOR-SUPPRESSOR ; ACUTE MYELOID-LEUKEMIA ; regulation ; ATM MUTATIONS ; B-CLL ; tumor suppressor gene ; transcript ; 11Q23 ; ATM ; CYCLIN-E ; GENOMIC REGION ; GTPASE-ACTIVATING PROTEIN ; INDUCED SKIN TUMORS ; MLL
    Abstract: Deletion of chromosome region 11q22-q23 defines a subgroup of patients with B-cell chronic lymphocytic leukemia (B-CLL) characterized by poor survival. Although the tumor-suppressor gene ATM in the consensus deletion region was found to be biallelically inactivated in about one third of B-CLL cases, in the majority of those who have this deletion, inactivation of the remaining ATM allele was not observed. To identify a second disease-associated gene, we investigated two B-CLL cases with translocation breakpoints in the critical 11q23 deletion region. In one case, a t(X;11)(q13;q23) was cloned and two novel genes were isolated. The breakpoint on 11q23 affected the ARHGAP20 gene, which encodes a protein predicted to be involved in the regulation of Rho family GTPases. The breakpoint on Xq13 occurred in BRWD3, which codes for a putative novel transcription factor. The rearrangement of ARHGAP20 and BRWD3 did not result in fusion transcripts, but it disrupted both genes. Mutation analysis of 28 B-CLL samples with monoallelic deletions and two B-CLL samples with 11q23 translocations detected no deleterious mutation in the remaining copy of ARHGAP20. Quantitative expression analysis in 22 B-CLLs revealed significant up-regulation of ARHGAP20 in CLL B cells, whereas BRWD3 was slightly down-regulated. Thus, deregulation of ARHGAP20 by altered gene expression or by gene disruption (but not point mutation) might be a general molecular mechanism of B-CLL leukemogenesis. (C) 2004 Wiley-Liss, Inc
    Type of Publication: Journal article published
    PubMed ID: 15543602
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  • 4
    Keywords: RECEPTOR ; APOPTOSIS ; EXPRESSION ; SURVIVAL ; Germany ; DISTINCT ; GENE ; GENE-EXPRESSION ; GENES ; ANTIGEN ; cell cycle ; CYCLE ; PROGNOSTIC-FACTORS ; CD38 EXPRESSION ; SUBSET ; GENOMIC ABERRATIONS ; MUTATION STATUS ; ANTIGEN RECEPTORS ; B-CELL RECEPTOR ; EXPRESSION PATTERNS ; APOPTOSIS-ASSOCIATED GENES ; PATHOMECHANISMS
    Abstract: The mutation status and usage of specific VH genes such as V3-21 and V1-69 are potentially independent pathogenic and prognostic factors in chronic lymphocytic leukemia (CLL). To investigate the role of antigenic stimulation, we analyzed the expression of genes involved in B-cell receptor (BCR) signaling/activation, cell cycle, and apoptosis control in CLL using these specific VH genes compared to VH mutated (VH-MUT) and VH unmutated (VH-UM) CLL not using these VH genes. V3-21 cases showed characteristic expression differences compared to VH-MUT (up: ZAP70 [or ZAP-70]; down: CCND2, P27) and VH-UM (down: PI3K, CCND2, P27, CDK4, BAX) involving several BCR-related genes. Similarly, there was a marked difference between VH unmutated cases using the V1-69 gene and VH-UM (up: FOS; down: BLNK, SYK, CDK4, TP53). Therefore, usage of specific VH genes appears to have a strong influence on the gene expression pattern pointing to antigen recognition and ongoing BCR stimulation as a pathogenic factor in these CLL subgroups
    Type of Publication: Journal article published
    PubMed ID: 16322480
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  • 5
    Keywords: APOPTOSIS ; CANCER ; CELLS ; EXPRESSION ; SURVIVAL ; CELL ; Germany ; GENE ; GENES ; PROTEIN ; SAMPLES ; cell cycle ; CELL-CYCLE ; DOWN-REGULATION ; TARGET ; DELETION ; LYMPHOMA ; MUTATION ; COMPONENT ; inactivation ; PATHOGENESIS ; MUTATIONS ; B-CELLS ; DEGRADATION ; POLYMERASE-CHAIN-REACTION ; point mutation ; REGULATOR ; TRANSCRIPTS ; ONCOLOGY ; TUMOR-SUPPRESSOR ; CLL ; ATM MUTATIONS ; POINT MUTATIONS ; LEVEL ; TARGET GENES ; analysis ; leukaemia ; ATM ; PP2A ; PHOSPHATASE ; CONFORMATION ; B-CELL ; apoptosis regulation ; B-cell chronic lymphocytic ; 11q22-q23 ; CUL5 ; NPAT ; PHOSPHATASE 2A ; PPP2R1B
    Abstract: Deletion of 11q22-q23 is associated with an aggressive course of B-cell chronic lymphocytic leukaemia (B-CLL). Since only in a subset of these cases biallelic inactivation of ATM was observed, we sought to identify other disease-associated genes within 11q22-q23 by analysing NFAT (cell-cycle regulation), CUL5 (ubiquitin-dependent apoptosis regulation) and PPP2R1B (component of the cell-cycle and apoptosis regulating PP2A) for point mutations and their expression in B-CLL by single-strand conformation polymorphism/sequence analysis of the transcripts and real-time polymerase chain reaction. Though none of the genes were affected by deleterious mutations, we observed a significant down-regulation of NPAT in B-CLL versus CD19+ B cells and of CUL5 in 11q deletion versus non-deletion B-CLL samples and measured reduced PPP2R1B transcript levels in a subset of B-CLL cases. Alternative splicing of PPP2R1B transcripts (skipping of exons 2/3, 3, 9) was associated with a reduced activity of protein phosphatase 2A. Together, these results implicate deregulation of the cell-cycle and apoptosis regulators NPAT, CUL5 and PPP2R1B and a role for these genes in the pathogenesis of B-CLL. (C) 2007 Elsevier Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 17449237
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  • 6
    Keywords: CANCER ; CELLS ; BLOOD ; CELL ; Germany ; human ; COMMON ; DISEASE ; RISK ; GENE ; SAMPLE ; SAMPLES ; TISSUE ; TIME ; PATIENT ; CONTRAST ; cell cycle ; CELL-CYCLE ; CYCLE ; treatment ; antibodies ; antibody ; NO ; AMPLIFICATION ; MALIGNANCIES ; MUTATION ; leukemia ; ABERRATIONS ; LYMPHOCYTES ; PROGNOSTIC-FACTORS ; INSTABILITY ; B-CELLS ; PROGNOSTIC FACTORS ; REPLICATION ; INDIVIDUALS ; T-LYMPHOCYTES ; T lymphocyte ; PERIPHERAL-BLOOD ; PROGNOSTIC FACTOR ; CD38 EXPRESSION ; HUMAN BREAST-TUMORS ; T lymphocytes ; POSSIBLE MECHANISM ; ARREST ; MALIGNANCY ; ONCOLOGY ; ACUTE MYELOID-LEUKEMIA ; chronic lymphocytic leukemia ; CLL ; GENOMIC ABERRATIONS ; B-cell chronic lymphocytic leukemia ; PROGNOSTIC-FACTOR ; CHROMOSOMAL INSTABILITY ; PHASE ; CYCLE ARREST ; USA ; correlation ; PROLIFERATIVE ACTIVITY ; B-LYMPHOCYTES ; EXTENT ; genomic ; B-CELL ; ANEUPLOIDY ; aberration ; correlates ; B cells ; B-cell chronic lymphocytic ; centrosome aberrations ; DOUBLING TIME ; GENE MUTATIONAL STATUS
    Abstract: B-cell chronic lymphocytic leukemia (CLL) is characterized by a high rate of clonal genomic alterations and a low proliferative activity with cell cycle arrest in G(0)/G(1) phase. Recently, centrosome aberrations have been described as a possible cause of chromosomal instability and aneuploidy in many human malignancies. To investigate whether centrosome aberrations do occur in CLL and whether they correlate with common prognostic factors and disease activity, we examined peripheral blood mononuclear cells (PBMC) from 70 patients with previously untreated CLL using an antibody to gamma-tubulin. All 70 CLL samples displayed significantly more cells with centrosome aberrations (median: 26.0%, range 11.0-41.5%) as compared to peripheral blood B lymphocytes from 20 age-matched, healthy individuals (median: 2.0 %, range 0-6 % p 〈 0.001). The extent of centrosome aberrations correlated with the proliferative activity of the CLL cases as measured by lymphocyte doubling time (p = 0.02) as well as with time to first treatment (p = 0.05). Accordingly, more centrosome aberrations were found in PHA-stimulated T lymphocytes from healthy individuals as well as in B cells from surgically removed tonsil tissue of patients with acute tonsillitis as compared to the peripheral blood B lymphocytes from the control group. In contrast, no correlation was observed between centrosome aberrations and immunoglobulin VH gene mutation status or cytogenetically defined risk groups. These findings suggest that, despite the common observation of most CLL cells remaining in G(0)/G(1) phase, their centrosome replication process is deregulated and correlates to the proliferative activity of CLL cells. (C) 2007 Wiley-Liss, Inc
    Type of Publication: Journal article published
    PubMed ID: 17417785
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  • 7
    Keywords: A, CLL, DISEASE, MDM2, polymorphism
    Type of Publication: Journal article published
    PubMed ID: 19709747
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  • 8
    Keywords: APOPTOSIS ; CANCER ; CELLS ; GROWTH ; CELL ; Germany ; PATHWAY ; PATHWAYS ; NETWORK ; NETWORKS ; SYSTEM ; DISEASE ; PROTEIN ; PROTEINS ; transcription ; ACTIVATION ; FAMILY ; TRANSCRIPTION FACTOR ; CONTRAST ; ALPHA ; TRANSCRIPTION FACTORS ; SUBUNIT ; ASSAY ; NUMBER ; SIGNALING PATHWAY ; SIGNALING PATHWAYS ; TNF ; signaling ; ELISA ; ONCOLOGY ; RESOURCE ; high throughput ; HIGH-THROUGHPUT ; TIMES ; IMMUNE ; Cellular signaling ; SHIFT ; B ACTIVITY ; chemiluminescent ; NF kappa B ; NF-kappaB ; NFkB
    Abstract: Contemporary research on cellular signaling has undergone a shift of focus from qualitative measurements of single signaling pathways to high-throughput quantitation of comprehensive signaling networks. Notably, nuclear factor-kappaB (NF kappa B) is a family of transcription factors involved in immune and inflammatory responses, developmental processes, cellular growth and apoptosis and is deregulated in a number of disease states. We have established a chemiluminescent oligonucleotide-based enzyme-linked immunosorbent assay (co-ELISA) that is simple and quantitative. In contrast to currently used assays, it allows quantitation of all NF kappa B components (i.e., RelA, p50, p52, RelB and c-Rel). In addition, it can make use of whole extract and does not require cumbersome nuclear/cytosolic fractionation, saving time and resources. Co-ELISA has a 3.5- to 43-fold higher signal-over-noise ratio than currently available assays, whereas the percent relative standard deviation is 3- to 6-fold lower. Furthermore, the novel method is faster than electrophoretic mobility shift assay, not restricted to transfectable cells as is the case for luciferase reporter assays and 10 times more cost efficient than commercially available ELISA assays. Co-ELISA is a sensitive, fast and cost-efficient quantitation method for all DNA-binding NF kappa B proteins that can be used in high-throughput experimentation
    Type of Publication: Journal article published
    PubMed ID: 19924814
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  • 9
    Abstract: BACKGROUND: Chronic lymphocytic leukemia has a variable clinical course. Genomic aberrations identify prognostic subgroups, pointing towards distinct underlying biological mechanisms that are poorly understood. In particular it remains unclear whether the prognostic subgroups of chronic lymphocytic leukemia are characterized by different levels of leukemogenic proteins. DESIGN AND METHODS: Expression of 23 proteins involved in apoptosis, proliferation, DNA damage, and signaling or whose genes map to chromosomal regions known to be critical in chronic lymphocytic leukemia was quantified in 185 cytogenetically well characterized cases of chronic lymphocytic leukemia using immunoblotting. Cases were categorized hierarchically into deletion(17p), deletion(11q), trisomy 12, deletion(13q) as sole abnormality or normal karyotype. Statistical analysis was performed for expression differences between these subgroups. In addition, the expression levels of CDK4, P27 and P53 were quantified over the clinical course and compared to levels in immunopurified B cells from healthy individuals. RESULTS: In subgroups with a good prognosis, differential expression was mainly seen for proteins that regulate apoptosis. In contrast, in cytogenetic subgroups with a worse prognosis, differential expression was mostly detected for proteins that control DNA damage and proliferation. Expression levels of CDK4, P27 and P53 were higher compared to those in B cells from healthy individuals and significantly correlated with increasing hierarchical risk. In addition, no significant longitudinal changes of expression levels of CDK4, P27 and P53 could be detected in chronic lymphocytic leukemia patients. CONCLUSIONS: Differences in expression levels of apoptosis- and proliferation-controlling proteins define distinct prognostic subgroups of chronic lymphocytic leukemia and uncover a correlation of levels of CDK4, P27 and P53 proteins with higher hierarchical risk.
    Type of Publication: Journal article published
    PubMed ID: 20713460
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  • 10
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