Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P04637 (p53)
77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Central nervous system (CNS) involvement is an unusual manifestation in multiple myeloma (MM). The molecular basis of CNS myeloma is poorly understood. MM is characterized by translocations involving the immunoglobulin heavy chain (IgH) locus and frequent 13q deletions. Alterations of p53 or c-myc in MM may represent secondary changes associated with disease progression. We investigated nine patients with CNS MM using interphase fluorescence in situ hybridization (FISH) combined with immunofluorescence detection of the cytoplasmic light chain (cIg-FISH) for the presence of above genomic aberrations. Of nine patients studied, eight cases had hemizygous p53 deletion and 4 had 13q deletions. Of the patients with 13q deletions, two had IgH translocations, one involving 4p16.3 (FGFR3), the other involving 16q23 (c-maf). The high incidence of p53 deletions detected by cIg-FISH in CNS myeloma may be a marker for chromosomal instability, and may be associated with metastatic features of myeloma cells.
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PMID:Multiple myeloma involving central nervous system: high frequency of chromosome 17p13.1 (p53) deletions. 1549 Dec 86

A simple high throughput micro-fluorescence in situ hybridisation technique (FISH) was used to detect chromosome 13 deletions (delta13), immunoglobulin heavy chain (IgH) rearrangements, t(11;14)(q13;q32), t(4;14)(p16;q32), t(14;16)(q23;q32), p53 loss, and numerical changes of chromosomes 3, 6, 7, 9, 10, 11 and 17 in 228 cases of multiple myeloma (MM), including 33 asymptomatic/smouldering MM (SMM). The patients were not part of a clinical trial and were from 30 different hospitals. In all, 98.4% of cases were abnormal, with 43% having IgH rearrangements and 42% Delta13. The low incidence of IgH rearrangements was due to a decrease in this finding with age (P = 0.001) and the relatively high proportion of elderly patients in our study population (41% >70 years old). The incidence of specific IgH translocations was t(4;14) 11%, t(11;14) 16% and t(14;16) 3%. Univariate statistical testing showed delta13 (P = 0.002), and t(14;16) (P = 0.005) to be associated with shorter survival. This effect was exaggerated for patient's aged 70 years or under but no effect on survival was seen for those over 70 years. In younger patients t(4;14) (P = 0.044) and p53 deletion (P < 0.001) were also significant poor prognostic indicators. Multivariate analysis showed delta13 and t(14;16) to be independent prognostic variables when considered with age and clinical parameters.
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PMID:Age has a profound effect on the incidence and significance of chromosome abnormalities in myeloma. 1599 Aug 62

Redox modification of thiol/disulfide interchange in proteins by selenium could lead to protein unfolding. When this occurs in the endoplasmic reticulum (ER), a process known as unfolded protein response (UPR) is orchestrated for survival through activation of PERK-eIF2alpha (PERK: double-stranded RNA-activated protein kinase-like ER kinase; eIF2alpha: eucaryotic initiation factor 2alpha), ATFalpha (ATFalpha: activating transcription factor 6) and inositol requiring 1 (IRE1)-x-box-binding protein 1 (XBP1) signalings. All three UPR transducer pathways were upregulated very rapidly when PC-3 cells were exposed to selenium. These changes were accompanied by increased expression of UPR target genes, including immunoglobulin heavy chain-binding protein/glucose-regulated protein, 78 kDa and CCAAT/enhancer binding protein-homologous protein/growth arrest- and DNA damage-inducible gene (CHOP/GADD153). Induction of BiP/GRP78, an ER-resident chaperone, is part of the damage control mechanism, while CHOP/GADD153 is a transcription factor associated with growth arrest and apoptosis in the event of prolonged ER stress. Knocking down BiP/GRP78 induction by small interference RNA produced a differential response of the three transducers to selenium, suggesting that the signaling intensity of each transducer could be fine-tuned depending on BiP/GRP78 availability. In the presence of selenium, CHOP/GADD153 expression was raised even higher by BiP/GRP78 knockdown. Under this condition, the selenium effect on wild-type p53-activated fragment p21 (p21(WAF)), cyclin-dependent kinase (CDK)1 and CDK2 was also magnified in a manner consistent with enhanced cell growth arrest. Additional experiments with CHOP/GADD153 siRNA knockdown strongly suggested that CHOP/GADD153 may play a positive role in upregulating the expression of p21(WAF) in a p53-independent manner (PC-3 cells are p53 null). Collectively, the above findings support the idea that UPR could be an important mechanism in mediating the anticancer activity of selenium.
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PMID:Enhanced selenium effect on growth arrest by BiP/GRP78 knockdown in p53-null human prostate cancer cells. 1620 45

Apoptosis protease-activating factor 1 (APAF-1), a transcriptional target of p53, is a cytosolic adaptor protein that links the mitochondrial apoptosis pathway to the caspase cascade. Here, we aimed to study the impact of APAF-1 expression levels on cell death induced by anticancer drugs or ionizing irradiation (IR) and disease prognosis in B-type chronic lymphocytic leukemia (B-CLL) patients. Samples from 138 patients with B-CLL were investigated for APAF-1 expression and p53 mutations. The results were related to survival data, in vitro cytotoxicity of various cytotoxic drugs and IR and clinico-pathological data. Variable APAF-1 expression was observed in all investigated B-CLL samples. Reduction in APAF-1 expression was observed at both mRNA and protein level indicating transcriptional silencing whereas mutation of p53 or the immunoglobulin heavy chain variable genes (IgH(V)) had no impact on APAF-1 expression. Surprisingly, APAF-1 loss did not result in resistance to cytotoxic therapies. Likewise, APAF-1 downregulation on its own showed no impact on disease prognosis. Nevertheless, a poor prognosis was observed in patients with loss of APAF-1 expression and additional p53 mutation. Thus, loss of APAF-1 may become relevant when additional core apoptosis signaling components are disrupted.
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PMID:Silencing of APAF-1 in B-CLL results in poor prognosis in the case of concomitant p53 mutation. 1633 30

Histone H2AX promotes DNA double-strand break (DSB) repair and immunoglobulin heavy chain (IgH) class switch recombination (CSR) in B-lymphocytes. CSR requires activation-induced cytidine deaminase (AID) and involves joining of DSB intermediates by end joining. We find that AID-dependent IgH locus chromosome breaks occur at high frequency in primary H2AX-deficient B cells activated for CSR and that a substantial proportion of these breaks participate in chromosomal translocations. Moreover, activated B cells deficient for ATM, 53BP1, or MDC1, which interact with H2AX during the DSB response, show similarly increased IgH locus breaks and translocations. Thus, our findings implicate a general role for these factors in promoting end joining and thereby preventing DSBs from progressing into chromosomal breaks and translocations. As cellular p53 status does not markedly influence the frequency of such events, our results also have implications for how p53 and the DSB response machinery cooperate to suppress generation of lymphomas with oncogenic translocations.
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PMID:H2AX prevents DNA breaks from progressing to chromosome breaks and translocations. 1642 10

The adverse prognostic role of cytogenetic abnormalities has recently been established in plasma cell dyscrasias. Modern techniques such as fluorescence in situ hybridization and comparative genomic hybridization have revealed a higher incidence of cytogenetic abnormalities in patients with multiple myeloma (MM) compared to conventional cytogenetics. Hypodiploidy and chromosome 13 abnormalities are found in more than 50% of myeloma patients, representing well known factors with adverse prognosis. Rearrangements involving the switch regions of immunoglobulin heavy chain (IgH) gene at 14q32 with various partner genes represent the most common structural abnormalities, having an incidence of 70% in MM. Structural abnormalities of chromosomes 17 and 8 involving the p53 and c-myc genes are considered to be less frequent events, but carry a poor prognosis. New therapeutic approaches such as non-myeloablative allotransplantation and modern therapeutic agents (thalidomide, lenalidomide, and bortezomib) and their combinations give promise for an improved therapeutic management of patients with MM. The detection of t(4;14), t(14;16), deletion of chromosome 13 on metaphase analysis, or deletion of p53 by FISH will define high-risk prognostic groups that are not generally controlled with high-dose melphalan and autologous stem cell transplantation (ASCT), and should therefore be treated with more investigational therapies. Alternatively, eligible patients who do not have these poor risk factors are more likely to benefit from a high-dose, melphalan-based, regimen followed by ASCT.
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PMID:Clinical implications of chromosomal abnormalities in multiple myeloma. 1675 64

The most frequent genetic aberrations in multiple myeloma (MM) are 13q deletions and translocations involving the immunoglobulin heavy chain gene (IGH). There have been no reports on the cytogenetic abnormalities found in Korean patients with MM. We investigated the actual prevalence and prognostic value of cytogenetic changes using fluorescence in situ hybridization (FISH). FISH studies with 12 different specific probes for the regions containing the genes or chromosome regions (13q, 1q, IGH, p53, MLL, p16, CEP 7, CEP 11, and CEP 12) were performed in 128 patients. The most frequent change found was 13q deletion (48%), followed by trisomy 1q (45%), IGH translocation (37%), and trisomy 11 (26%). Among the three different probes used to detect 13q deletion, D13S25 (48/58) was the most sensitive probe compared to RB (43/58) and D13S319 (39/58). Among the patients showing one or more changes by FISH, 75% (82/110) had a 13q deletion, a trisomy 1q, or an IGH translocation. Azotemia, anemia, thrombocytopenia, intramedullary plasmacytosis, and stage were significantly associated with the 13q deletion; serum beta(2)-microglobulin, thrombocytopenia, and intramedullary plasmacytosis were also related to trisomy 1q. The pattern of molecular cytogenetic changes in Korean patients with MM is somewhat different from what has been observed in reported Caucasian populations: 37 versus 50-70% with regard to the IGH translocation. The prevalence of the 13q deletion was similar in Korean and Caucasian populations, 48 versus 30-50%. We suggest that the detection of at least these three genetic changes, 13q- trisomy 1q, and an IGH rearrangement, would be helpful for follow-up of Korean patients with MM.
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PMID:Identification of 13q deletion, trisomy 1q, and IgH rearrangement as the most frequent chromosomal changes found in Korean patients with multiple myeloma. 1684 2

To maintain genomic stability and ensure the fidelity of chromosomal transmission, cells respond to various forms of genotoxic stress, including DNA double-stranded breaks (DSBs), through the activation of DNA damage response signaling networks. In response to DSBs as induced by ionizing radiation (IR), during DNA replication, or through immunoglobulin heavy chain (IgH) rearrangements in B cells of lymphoid origin, the phosphatidyl inositol-like kinase (PIK) kinases ATM (mutated in ataxia telangiectasia), ATR (ATM and Rad3-related kinase), and the DNA-dependent protein kinase (DNA-PK) activate signaling pathways that lead to DSB repair. DSBs are repaired by either of two major, non-mutually exclusive pathways: homologous recombination (HR) that utilizes an undamaged sister chromatid template (or homologous chromosome) and non- homologous end joining (NHEJ), an error prone mechanism that processes and joins broken DNA ends through the coordinated effort of a small set of ubiquitous factors (DNA-PKcs, Ku70, Ku80, artemis, Xrcc4/DNA lig IV, and XLF/Cernunnos). The PIK kinases phosphorylate a variety of effector substrates that propagate the DNA damage signal, ultimately resulting in various biological outputs that influence cell cycle arrest, transcription, DNA repair, and apoptosis. A variety of data has revealed a critical role for p53-binding protein 1 (53BP1) in the cellular response to DSBs including various aspects of p53 function. Importantly, 53BP1 plays a major role in suppressing translocations, particularly in B and T cells. This report will review past experiments and current knowledge regarding the role of 53BP1 in the DNA damage response.
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PMID:Tying the loose ends together in DNA double strand break repair with 53BP1. 1694 45

In the last decades, considerable changes in the classification of lymphomas have been made. In addition to morphology and immunohistochemistry, the last WHO (2001) classification also utilizes cytogenetics and molecular biology. In many cases classification notices oncogenic mechanisms. The authors describe some differences in immunophenotype in certain entities: chronic lymphocytic leukaemia/small lymphocytic lymphoma--CLL/SLL, follicular lymphoma--FL, mantle cell lymphoma--MCL, diffuse large B-cell lymphoma--DLBCL, and anaplastic large cell lymphoma--ALCL, mainly with respect to prognosis. The authors point out to heterogeneity within the individual types of lymphomas from the point of view of morphology, immunohistochemistry and molecular biology. Recently it has been shown, that differences in prognosis are not limited to individual nosologic entities, but also may be found within the particular category of lymphoma. For example, CLL/SLL is divided in two different subunits according to mutational status of variable segment (VH) of the immunoglobulin heavy chain gene. The cases with unmutated VH segment display progressive disease which is in contrast to cases with the same morphology but with mutated VH segment. Similar differences were found in MCL. Attention is drawn to oncogenic and apoptosis-regulating mechanisms, such as gene p53 and the Bcl-2 family.
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PMID:[Non-Hodgkin's lymphomas (from Rappaport to WHO 2001 and nowadays). Review]. 1762 75

The RecQ family helicase BLM is critically involved in the maintenance of genomic stability, and BLM mutation causes the heritable disorder Bloom's syndrome. Affected individuals suffer from a predisposition to a multitude of cancer types and an ill-defined immunodeficiency involving low serum Ab titers. To investigate its role in B cell biology, we inactivated murine Blm specifically in B lymphocytes in vivo. Numbers of developing B lymphoid cells in the bone marrow and mature B cells in the periphery were drastically reduced upon Blm inactivation. Of the major peripheral B cell subsets, B1a cells were most prominently affected. In the sera of Blm-deficient naive mice, concentrations of all Ig isotypes were low, particularly IgG3. Specific IgG Ab responses upon immunization were poor and mutant B cells exhibited a generally reduced Ab class switch capacity in vitro. We did not find evidence for a crucial role of Blm in the mechanism of class switch recombination. However, a modest shift toward microhomology-mediated switch junction formation was observed in Blm-deficient B cells. Finally, a cohort of p53-deficient, conditional Blm knockout mice revealed an increased propensity for B cell lymphoma development. Impaired cell cycle progression and survival as well as high rates of chromosomal structural abnormalities in mutant B cell blasts were identified as the basis for the observed effects. Collectively, our data highlight the importance of BLM-dependent genome surveillance for B cell immunity by ensuring proper development and function of the various B cell subsets while counteracting lymphomagenesis.
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PMID:Genomic instability resulting from Blm deficiency compromises development, maintenance, and function of the B cell lineage. 1910 66


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