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: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leukocyte trafficking is critically regulated by chemokines and their receptors. The involvement of the skin in certain subsets of T-cell malignancies has been explained by the discovery of an interaction between the thymus and activation-regulated chemokine (TARC), which is abundant in the skin, and its receptor, CC chemokine receptor 4 (CCR4), which is expressed in the tumor cells. We describe a diffuse large B-cell lymphoma (DLBCL) that showed CCR4 expression with involvement of the skin. A 55-year-old man presented with a giant skin ulcer of the right axilla, and his disease was diagnosed as DLBCL. Further clinical examination revealed an ulcerated gastric lymphoma lesion. Immunohistochemical and real-time reverse transcriptase-polymerase chain reaction analyses showed that the tumor cells were positive for CCR4, and TARC was expressed at extremely high levels in the lymphoma-affected skin. These observations suggest that the interaction between CCR4 and TARC played a significant role in the involvement of the skin in this case, similar to what has been observed in certain subsets of T-cell malignancies. To the best of our knowledge, this report is the first of a CCR4-positive B-cell lymphoma. The present case provides new insights into the pathogenesis of skin involvement in B-cell lymphomas.
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PMID:CC chemokine receptor 4-positive diffuse large B-cell lymphoma involving the skin: a case report. 1614 48

To better characterize ocular adnexal marginal zone lymphoma of mucosa-associated lymphoid tissue (MZL-MALT), we analyzed the clinical and pathologic features of 23 patients (11 men, 12 women, median age 66 years). The tumor was confined to one ocular structure in 18 cases (conjunctiva, n=8; orbit, n=8; or lacrimal gland, n=2). Concurrent extraorbital disease was detected by the staging procedure in five patients, and preferentially involved other MALT sites. Histogenetic B cell marker studies, available in 13 cases, showed an early post-germinal center (GC) phenotype (BCL-6(-)/IRF4(+)/CD138(-)) (n=5) or a late post-GC phenotype (BCL-6(-)/IRF4(+)/CD138(+)) (n=8), which could be helpful for discrimination from other types of small-B cell lymphoma. BCL10 was positive in 12 of 13 patients tested, with nuclear (n=4) or cytoplasmic (n=8) immunoreactivity. These staining patterns ruled out t(1;14)(p22;q32) translocation. T(11;18)(q21;q21), another MZL-MALT-specific translocation, was detected by reverse transcriptase polymerase chain reaction in four of 15 patients tested. Clinical outcome was excellent but the overall relapse rate was 26.1% with a median follow-up of 39 months (range 6-132 months). Regardless of the disease stage at diagnosis, combined chemotherapy and radiotherapy seemed to be more effective than chemotherapy alone in ocular adnexal MZL-MALT, as persistent complete remission was achieved in nine patients receiving combination therapy, while six of 14 patients treated with chemotherapy alone relapsed.
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PMID:Ocular adnexal marginal zone B cell lymphoma: a clinical and pathologic study of 23 cases. 1632 6

We reported previously that various radiocontrast media cause apoptosis in porcine proximal tubular (LLC-PK(1)) cells, in which reduction in B-cell lymphoma (Bcl)-2 expression and caspase-3 activation are implicated. In the present study, we investigated a role for ceramide in radiocontrast media-induced apoptosis in renal tubular cells. LLC-PK(1) cells were exposed to radiocontrast media for 30 min, followed by incubation for 24 h in normal medium. Cell viability was assessed by 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt assay, while apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling stain. Immunofluorescent stains were performed using antibodies against phosphorylated Akt (pAkt) and cAMP response element binding protein (CREB) (pCREB), and ceramide. The mRNA expression and protein content of Bcl-2 were determined by reverse transcriptase-polymerase chain reaction and enzyme immunoassay, respectively. In vivo model of contrast-induced renal injury was induced in mice with unilateral renal occlusion. The cell injury induced by the nonionic radiocontrast medium ioversol was reversed by inhibiting de novo ceramide synthesis with fumonisin B(1) (FB(1)) and L-cycloserine, but not by suppressing sphingomyelin breakdown with D609. FB(1) reversed ioversol-induced decrease in the immunoreactivities of pAkt and pCREB, reduction in Bcl-2 expression and caspase-3 activation. Like ioversol, C2 ceramide and the Akt inhibitor Src homology-6 induced apoptosis by reducing pAkt and pCREB-like immunoreactivities, lowering Bcl-2 expression and enhancing caspase-3 activity. Indeed, various radiocontrast media, excluding iodixanol which showed the least nephrotoxicity, enhanced ceramide-like immunoreactivity. The role for de novo ceramide synthesis was also shown in the in vivo model of radiocontrast nephropathy. We demonstrated here for the first time that the enhancement of de novo ceramide synthesis contributes to radiocontrast nephropathy.
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PMID:Involvement of de novo ceramide synthesis in radiocontrast-induced renal tubular cell injury. 1640 18

We have previously reported functional alterations in vitro in the hematopoietic compartment of patients with diffuse large B-cell lymphoma (DLBCL). In the present study, we assessed the presence of molecular alterations in hematopoietic cells derived from DLBCL marrow. Accordingly, the expression of four genes (i.e. ice, bcl-2, c-myc and p53) was assessed both, at the mRNA and protein levels, in three cell populations: (i) population I, consisting of morphologically recognizable precursor and mature cells; (ii) population II, enriched for CD34+ Lineage-negative (Lin-) cells; and (iii) population III, enriched for CD34+ CD38- Lin- cells. By using a multiplex reverse transcriptase-polymerase chain reaction system, we observed reduced expression of bcl-2 in population I, and c-myc in populations I and II from lymphoma marrow compared to their normal counterparts. On the other hand, expression of ice and p53 was not significantly different when comparing normal and DLBCL samples. At the protein level, all four molecules were expressed in a higher proportion of samples from DLBCL patients than in marrow samples from normal subjects. Interestingly, these proteins were expressed predominantly in primitive cells (population III), whereas the proportion of positive samples was reduced in population II, and even more in population I. Taken together, our results indicate that, in DLBCL, molecular alterations are present in hematopoietic cells from bone marrow, including morphologically recognizable precursor and mature cells, as well as primitive hematopoietic progenitors (CD34+ cells). To date, the physiological implications of these alterations are still unclear, and further studies should be undertaken to address this issue.
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PMID:Expression of ice, bcl-2, c-myc and p53 in different bone marrow cell populations from patients with diffuse large B-cell lymphoma. 1669 May 25

Inhibition of apoptosis seems to play an important role in the pathogenesis of marginal zone lymphoma. Apoptosis regulator B-cell lymphoma 10 (BCL10) may show aberrant nuclear localization in some aggressive extracutaneous MALT lymphomas, often in association with a MALT1 gene t(11;18)(q21;q21) translocation. The possible occurrence of this association in primary cutaneous marginal zone lymphoma (PCMZL) remains insufficiently explored. The aim of this study was to evaluate BCL10 protein expression pattern and its possible relationship to the presence of t(11;18)(q21;q21) and other MALT1 gene abnormalities in PCMZL and to assess their clinical significance. The study included 42 consecutive PCMZL patients diagnosed on the basis of the World Health Organization/European Organization for the Research and Treatment of Cancer classification criteria. BCL10 expression was immunohistochemically evaluated in all cases, whereas t(11;18)(q21;q21) reverse transcriptase polymerase chain reaction amplification was performed on 21 samples. In addition, the presence of other MALT1 gene translocations was explored in 26 samples by interphase fluorescence in situ hybridization using a MALT1 locus-specific probe. We observed the presence of aberrant nuclear BCL10 expression in a significant number of PCMZL cases (36%, 15/42). This aberrant expression was significantly related to the development of extracutaneous disease. In contrast, neither the t(11;18)(q21;q21) translocation nor other MALT1 gene translocations could be demonstrated. t(11;18)(q21;q21), strongly linked to extracutaneous MALT lymphomas, does not seem to play a role in PCMZL. The participation of other MALT1 gene translocations in PCMZL pathogenesis seems also unlikely.
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PMID:Aberrant nuclear BCL10 expression and lack of t(11;18)(q21;q21) in primary cutaneous marginal zone B-cell lymphoma. 1678 87

The TLX1/HOX11 homeobox gene was originally identified at the recurrent t(10;14)(q24;q11) translocation breakpoint, a chromosomal abnormality observed in 5-7% of T-cell acute lymphoblastic leukemias (T-ALLs). Proviral insertional mutagenesis studies performed on transgenic mice ectopically expressing TLX1/HOX11 in B lymphocytes (IgHmu-HOX11(Tg) mice) revealed the Ubr1 gene locus as a frequent site of proviral insertion, concomitant with accelerated development of diffuse large B-cell lymphoma. Insertion into this genomic region was confirmed by Southern blotting and by the ability to generate a polymerase chain reaction (PCR) amplicon across the viral-genome junction. Western immunoblot and semiquantitative reverse transcriptase-PCR analysis revealed downregulated expression of the Ubr1 gene product subsequent to viral integration. Loss or reduced levels of Ubr1 expression was associated with 5/14 spontaneous B-cell lymphomas in IgHmu-HOX11(Tg) mice and one of nine primary human T-ALLs. To gain mechanistic insight into the cooperativity between TLX1/HOX11 and Ubr1, IgHmu-HOX11(Tg)/Ubr1(-/-) mice were generated. IgHmu-HOX11(Tg)/Ubr1(-/-) mice exhibited a modest but statistically significant acceleration of disease onset relative to IgHmu-HOX11(Tg)/Ubr1(+/-) mice. Moreover, micronucleus assays to detect for chromosome missegregation were conducted and revealed increased presence of micronuclei in IgHmu-HOX11(Tg)/Ubr1(-/-) primary B lymphocyte cultures, and in both TLX1/HOX11-overexpressing T cell lines and fibroblast cultures following transfection with short interfering RNAs (siRNAs) targeting Ubr1. Karyotyping of primary B lymphocyte cultures revealed increased incidences of hypodiploid karyotypes. Finally, mitotic figures analysed from Ubr1 siRNA-transfected fibroblast cultures revealed no defects in chromosome congression to the metaphase plate, but increased incidences of atypical anaphase figures, including the development of anaphase bridges and lagging chromosomes. Based on these findings, we identify a synergistic role between TLX1/HOX11 overexpression and Ubr1 inactivation in promoting chromosome missegregation, permitting the accrual of additional chromosome losses and cytogenic abnormalities en route to malignancy.
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PMID:Loss of Ubr1 promotes aneuploidy and accelerates B-cell lymphomagenesis in TLX1/HOX11-transgenic mice. 1686 88

Non-Hodgkin's lymphoma (NHL) is a group of malignancies of the immune system with variable clinical behaviors and diverse molecular features. Despite the progress made in classification of NHLs based on classical methods, molecular classifications are a work in progress. Toward this goal, we used an array-based technique called differential methylation hybridization (DMH) to study small B-cell lymphoma (SBCL) subtypes. A total of 43 genomic DMH experiments were performed. From these results, several statistical methods were used to generate a set of differentially methylated genes for further validation. Methylation of LHX2, POU3F3, HOXC10, NRP2, PRKCE, RAMP, MLLT2, NKX6.1, LRP1B and ARF4 was validated in cell lines and patient samples and demonstrated subtype-related preferential methylation patterns. For LHX2 and LRP1B, bisulfite sequencing, real-time reverse transcriptase-polymerase chain reaction and induction of gene expression following treatment with the demethylating agent, 5'-aza-2'-deoxycytidine, were confirmed. This new epigenetic information is helping to define molecular portraits of distinct subtypes of SBCL that are not recognized by current classification systems and provides valuable potential insights into the biology of these tumors.
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PMID:Differential DNA methylation patterns of small B-cell lymphoma subclasses with different clinical behavior. 1704 36

Recent microarray gene expression profiling studies have identified gene signatures predictive of outcome, so-called "indicator" genes, for diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). However, measurement of these genes in routine practice remains difficult. We applied real-time polymerase chain reaction (PCR) to polyA cDNAs prepared from 106 archived human frozen lymph nodes (63 of FL, 25 of DLBCL, 10 reactive lymph nodes, and cases with paired samples of FL [4] and subsequent DLBCL [4]). Reverse transcription and polyA reverse transcriptase (RT)-PCR was performed, and resultant cDNA was probed by real-time PCR for 36 candidate indicator genes, selected from microarray studies. Nine genes showed statistically significant different expression between FL and DLBCL, including cyclin B, COL3A1, NPM3, H731, PRKCB1, OVGL, ZFPC150, HLA-DQ-a, and XPB. Of these, cyclin B, NPM3, and COL3A1 were higher in DLBCL. Six genes showed statistically significant higher expression in the neoplastic nodes compared with reactive nodes, namely PRKCB1, BCL-6, EAR2, ZFX, cyclin B, YY1. High levels of YY.1 were associated with a shorter survival interval in both FL and DLBCL. The method is simple, sensitive, and robust, facilitating routine use and may be used as a platform for clinical measurement of prognostic gene signatures.
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PMID:Clinical quantitation of diagnostic and predictive gene expression levels in follicular and diffuse large B-cell lymphoma by RT-PCR gene expression profiling. 1725 58

The Mix1 homeobox-like (MIXL1) gene encodes a paired class homeobox transcription factor that is involved in embryogenesis. Previous studies have shown that the MIXL1 gene product is expressed in B- and T-cell progenitors of normal bone marrow and, in some cell lines derived from hematopoietic neoplasms. The status of MIXL1 expression and subcellular localization in human lymphomas is unknown. Using a highly specific antibody, we assessed for MIXL1 expression in lymphoma cell lines of B- and T-cell lineage by reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunohistochemistry. We also assessed for MIXL1 expression using immunohistochemical methods in 193 lymphoid tumors, including 140 B-cell non-Hodgkin lymphomas (NHL), 36 T-cell NHL, and 17 Hodgkin lymphomas (HL). MIXL1 was detected predominantly in the nuclear fraction of all cell lines tested and was predominantly nuclear in primary tumor specimens. Based on the distribution of the staining results (histogram), a 50% cutoff was selected for high versus low MIXL1 expression. High MIXL1 expression was detected more frequently in Burkitt lymphoma and diffuse large B-cell lymphoma compared with other types of B-cell NHL (P < .0001, chi(2) test). Most cases of T-cell NHL and all cases of HL also highly expressed MIXL1. Most plasma cell myelomas were negative for MIXL1, but rare cases had low MIXL1 expression. MIXL1 expression significantly correlated with proliferation index (Ki-67) in B-cell NHL (P < .0001). The frequent and high expression of MIXL1 in aggressive B-cell NHL, T-cell NHL, and HL suggests that MIXL1 may be involved in lymphomagenesis.
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PMID:Differential expression of the human MIXL1 gene product in non-Hodgkin and Hodgkin lymphomas. 1730

Comprehensive analysis of gene expression using RNA extracted from frozen lymphoma specimens is becoming increasingly important for understanding disease pathogenesis, disease subclassification, and prognostication. As paraffin tissues are widely available whereas frozen specimens are not, development of gene expression analysis based on RNA extracted from paraffin-embedded tissues would facilitate application of the accumulated knowledge to a sample type that is typical of clinical practice. In the present study, we have developed and optimized methods of RNA extraction from paraffin-embedded lymphoid tissues. In contrast to previously suggested methods of RNA extraction from paraffin, our method uses sodium dodecyl sulfate that better preserves the extracted RNA and is optimized for more complete proteinase K digestion to release RNA from its complexes with protein. These modifications yield long RNA fragments up to 2000 bp enabling amplification of long amplicons. This allows usage of paraffin specimens for molecular rescue of RNA transcripted from rearranged clonal immunoglobulin genes-an advance that may increase the eligibility of lymphoma patients for immunotherapeutic approaches. Furthermore, real-time polymerase chain reaction analysis of expression of genes implicated in determination of prognosis of diffuse large B-cell lymphoma patients demonstrated an extremely high correlation (R>0.90) in normalized gene expression between paired frozen and formalin-fixed, paraffin-embedded specimens. Similarly, good correlation was also observed in gene array studies. These results suggest that the methods of RNA extraction we propose are suitable for giving accurate real-time quantitative reverse transcriptase-polymerase chain reaction results, array gene expression profiling, and molecular rescue of RNA transcripted from rearranged immunoglobulin genes for diagnostic and immunotherapeutic approaches.
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PMID:Optimization of RNA extraction from formalin-fixed, paraffin-embedded lymphoid tissues. 1752 74


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