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:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Selective inhibition of the BCR-ABL tyrosine kinase by imatinib (Gleevec) (formerly STI571) is a promising new therapeutic strategy in patients with chronic myelogenous leukemia (CML). Despite significant hematologic and cytogenetic responses, resistance occurs in patients with chronic phase (CP) and advanced disease. A cohort of 72 patients with CML in myeloid blast crisis (BC) (n = 34), lymphoid BC (n = 2), accelerated phase (AP) (n = 16), CP (n = 18), and BCR-ABL(+) acute lymphoblastic leukemia (ALL) (n = 2) resistant to imatinib were investigated. Median levels of BCR-ABL transcripts, determined by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR), were not significantly changed at the time of resistance, but seven of 55 patients showed a greater than 10-fold increase in BCR-ABL levels. Genomic amplification of BCR-ABL was found in two of 32 patients evaluated by fluorescence in situ hybridization (FISH). Additional chromosomal aberrations were observed in 19 of 36 patients and point mutations of the ABL tyrosine kinase domain resulting in reactivation of the BCR-ABL tyrosine kinase were detected in 29 of 72 patients. Resistance may be caused by BCR-ABL-independent or BCR-ABL-dependent mechanisms. A thorough evaluation of resistant cases is required to suggest therapeutic measures in the individual case. Clonal selection of resistant cells harboring a BCR-ABL mutation might be reversed by stopping imatinib therapy and switching to chemotherapy. Combination therapy from the start of treatment to reduce the frequency of resistance is currently being evaluated with several drugs.
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PMID:Cytogenetic and molecular mechanisms of resistance to imatinib. 1278 79

Kinase domain receptor (KDR) and Semaphorin3 (Sema3) have a functional relationship and are expressed in human bone marrow (BM). We cultured in vitro bone marrow stromal cells (BMSCs) and collected nonadherent cells from patients with acute myeloid leukemia (AML), chronic myelogenous leukemia (CML), acute lymphoblastic leukemia (ALL) and normal individuals. Reverse transcriptase polymerase chain reaction enzyme-linked immunosorbent assay (RT-PCR-ELISA) was performed to examine KDR and Sema3 genes expression, using beta2 microglobulin as an internal reference. KDR expression ratio in normal control BMSCs (97.0%, 32/33) was higher than in its corresponding nonadherent cells (70.8%, 17/24). KDR expression levels in ALL BMSCs and AML nonadherent cells were significantly higher than in normal controls. Sema3 expression ratios in nonadherent cells from AML (78.6%, 11/14) and CML (71.4%, 10/14) were both significantly lower than in normal control (100%, 27/27), its expression levels were also significantly lower than in normal control. Sema3 expression level in normal BMSCs was significantly lower than in nonadherent cells. Sema3 and KDR genes expression levels displayed a significantly positive correlation in normal control and ALL nonadherent cells (r=0.703, P=0.002; r=0.999, P=0.001). These results suggests that KDR may play a critical role in sustaining the hematopoietic microenvironment due to its high expression, and that KDR may be involved in pathogenesis of AML and ALL. Sema3 could also sustain the survival of hematopoietic cells with its high expression, while Sema3 gene expression may be inhibited in AML and CML.
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PMID:KDR and Sema3 genes expression in bone marrow stromal cells and hematopoietic cells from leukemia patients and normal individuals. 1608 43

ABL1 amplification, due to a cryptic episomal translocation NUP214/ABL1, is a novel finding in T-cell acute lymphoblastic leukemia (ALL). Here we report on the incidence and clinical features of this genetic defect in a series of 30 consecutive adult T-cell ALL patients. Multiple copies of the ABL1 gene were detected in two patients (6.6%), one with the karyotype 46,XY,t(1;3)(p36;p21),del(6)(q23)/46,XY and the other without analyzable metaphases. Metaphase/interphase fluorescence in situ hybridization (FISH) detected multiple uncountable signals corresponding to ABL1 in mitotic cells and nuclei from both patients. In one patient, no signals corresponded with the 9p21 chromosomal region, which contains the p16INK4a gene, and in the other one signal was observed. Quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) demonstrated that in these patients ABL1 gene expression was 14- and 18-fold greater than in normal controls, and returned to normal levels only when complete remission was achieved. We reached the following conclusions: (1) FISH is the only technique that promptly identifies T-cell ALL patients with ABL1 amplification, (2) quick identification with FISH is fundamental in the clinic because this T-cell ALL subset is imatinib sensitive but may become resistant due to development of additional mutations, and (3) ABL1 quantitative RT-PCR may be easily applied to monitor minimal residual disease.
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PMID:ABL1 amplification in T-cell acute lymphoblastic leukemia. 1621 63

We have reported previously that Delta9-tetrahydrocannabinol (Delta9-THC) treatment of resting human and murine splenic T cells robustly elevated intracellular calcium ([Ca2+]i). The objective of the present investigation was to examine the putative role of [Ca2+]i store depletion and store-operated calcium (SOC) and receptor-operated cation (ROC) channels in the mechanism by which Delta9-THC increases [Ca2+]i in the cannabinoid-2 receptor-expressing human peripheral blood-acute lymphoid leukemia (HPB-ALL) human T cell line. By using the smooth endoplasmic reticulum Ca2+-ATPase pump inhibitor, thapsigargin, and the ryanodine receptor antagonist, 8-bromo-cyclic adenosine diphosphate ribose, we demonstrate that the Delta9-THC-mediated elevation in [Ca2+]i occurs independently of [Ca2+]i store depletion. Furthermore, the ROC channel inhibitor, SK&F 96365 was more efficacious at attenuating the Delta9-THC-mediated elevation in [Ca2+]i than SOC channel inhibitors, 2-aminoethoxydiphenyl borate and La3+. Recently, several members of the transient receptor potential canonical (TRPC) channel subfamily have been suggested to operate as SOC or ROC channels. In the present studies, treatment of HPB-ALL cells with 1-oleoyl-2-acetyl-sn-glycerol (OAG), a cell-permeant analog of diacylglycerol (DAG), which gates several members of the TRPC channel subfamily, rapidly elevated [Ca2+]i, as well as prevented a subsequent, additive elevation in [Ca2+]i by Delta9-THC, independent of protein kinase C. Reverse transcriptase-polymerase chain reaction analysis for TRPC1-7 showed that HPB-ALL cells express detectable mRNA levels of only TRPC1. Finally, small interference RNA knockdown of TRPC1 attenuated the Delta9-THC-mediated elevation of [Ca2+]i. Collectively, these results suggest that Delta9-THC-induced elevation in [Ca2+]i is attributable entirely to extracellular calcium influx, which is independent of [Ca2+]i store depletion, and is mediated, at least partially, through the DAG-sensitive TRPC1 channels.
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PMID:Induction of intracellular calcium elevation by Delta9-tetrahydrocannabinol in T cells involves TRPC1 channels. 1624 7

This study reports a 1-year-old boy with precursor B cell acute lymphoblastic leukemia (ALL) carrying t(16;21)(p11;q22). Reverse transcriptase-polymerase chain reaction (RT-PCR) and direct sequence analysis showed TLS/FUS-ERG chimeric mRNA with a novel junctional pattern of exon 7 of TLS/FUS and exon 6 of ERG. He did not respond to ALL-oriented therapy. Complete remission (CR) was achieved by chemotherapy oriented for acute myeloid leukemia. Allogenic bone marrow transplantation was done and he has been in CR for 24 months. TLS/FUS-ERG chimeric mRNA was not detected after CR. This is the first report of an ALL patient with a TLS/FUS-ERG fusion transcript.
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PMID:TLS/FUS-ERG fusion gene in acute lymphoblastic leukemia with t(16;21)(p11;q22) and monitoring of minimal residual disease. 1626 89

Infant acute lymphoblastic leukemia (ALL) has a poor therapeutic outcome despite attempts to treat it based on prognostic factor-guided therapy. This is the first cooperative group trial characterizing all infants at the molecular level for MLL/11q23 rearrangement. All infants enrolled on Children's Cancer Group (CCG) 1953 were tested for MLL rearrangement by Southern blot and the 11q23 translocation partner was identified (4;11, 9;11, 11;19, or "other") by reverse-transcriptase polymerase chain reaction (PCR). One hundred fifteen infants were enrolled; overall event-free survival (EFS) was 41.7% (SD = 9.2%) and overall survival (OS) was 44.8% at 5 years. Five-year EFS for MLL-rearranged cases was 33.6% and for MLL-nonrearranged cases was 60.3%. The difference in EFS between the 3 major MLL rearrangements did not reach statistical significance. Multivariate Cox regression analyses showed a rank order of significance for negative impact on prognosis of CD10 negativity, age younger than 6 months, and MLL rearrangement, in that order. Toxicity was the most frequent cause of death. Relapse as a first event in CCG 1953 was later (median, 295 days) compared with CCG 1883 historic control (median, 207 days). MLL/11q23 rearrangement, CD10 expression, and age are important prognostic factors in infant ALL, but molecular 11q23 translocation partners do not predict outcome.
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PMID:Analysis of prognostic factors of acute lymphoblastic leukemia in infants: report on CCG 1953 from the Children's Oncology Group. 1655 94

A 5-year-old boy who initially presented with ALL and relapsed 4 months later with AML was found to have an add(19) in the leukemia cells. FISH revealed that the add(19) was really a cryptic t(l2;l9)(p13.3;p13.3) interrupting E2A (TCF3). Nucleotide sequences of cloned genomic fragments with the E2A rearrangements revealed that the der(12) contained E2A joined to an intron of the NOLI (p120) gene. Reverse transcriptase (RT)-PCR of patient lymphoblast RNA showed expression of in-frame fusion cDNAs consisting of most of NOL1 fused to the 3' portion of E2A that encoded part of the second transcriptional activation domain and the DNA binding and protein dimerization motifs. The reciprocal der(19) E2A genomic rearrangements included 5' regions of E2A joined to an intron of the ZNF384 (NMP4, CIZ) gene, located approximately 450 kb centromeric to NOL1 on chromosome 12. RT-PCR showed expression of in-frame E2A-ZNF384 fusion cDNAs. To our knowledge, this is the second report of a chromosome translocation in leukemia resulting in two different gene fusions. This is the first report of expression of E2A fusion protein that includes the DNA binding and protein dimerization domains due to a more proximal break in E2A compared to those described previously.
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PMID:E2A-ZNF384 and NOL1-E2A fusion created by a cryptic t(12;19)(p13.3; p13.3) in acute leukemia. 1818 22

The aim of this study is to evaluate (1) the human telomerase-specific reverse transcriptase (hTERT) mRNA expression in childhood acute leukemia, (2) the association between the hTERT mRNA expression with the patients' characteristics and the known prognostic factors and (3) the correlation of the patients' survival with the initial hTERT mRNA value at diagnosis. A total of 40 newly diagnosed patients consist of children [31 cases with acute lymphoblastic leukemia (ALL) and 9 cases with acute myeloblastic leukemia (AML)] were prospectively included into the study. The online real-time reverse-transcriptase PCR was used for the quantification of hTERT in bone marrow (BM). All cases were re-evaluated for their survival after 2 years. The highest hTERT mRNA value was observed in Pre B-cell ALL patients followed by B-cell ALL, T-cell ALL and AML. The hTERT mRNA relative ratio difference between the ALL and AML groups was significant. No significant association was found when hTERT mRNA expression was evaluated in relation with the hematological parameters (except hemoglobin level), blast percentages and the risk groups. No significant difference was determined between the rate of complete remission and relapse of cases with the hTERT mRNA values in all malignancy groups. Patients who had higher initial hTERT mRNA values showed significantly longer disease-free survival (DFS) and overall survival (OS) in ALL (P = 0.000 and 0.01, respectively). Although DFS and OS was longer in AML patients with lower initial hTERT mRNA, the difference was not significant. In conclusion, the hTERT mRNA expression values were not significantly associated with the known prognostic factors in children both with ALL and AML. hTERT mRNA value is a significant factor for childhood ALL at diagnosis in relation to the estimated survival.
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PMID:The evaluation of hTERT mRNA expression in acute leukemia children and 2 years follow-up of 40 cases. 1829 58

This study was purposed to investigate lrp16 gene expression in leukemia cell lines and bone marrow cells of leukemia patients and explore the relationship between lrp16 gene expression and development of leukemia. Reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to test the lrp16 mRNA expression in 4 leukemia cell lines, including K562 (CML), HL-60 (APL), MOLT4 (ALL) and U937 cell lines, as well as in bone marrow-derived cells from 115 patients with leukemia. The effect of lrp16 gene expression on genesis and progression of leukemia was analyzed according to clinicopathological features. The results indicated that positive expression of lrp16 mRNA was found in all 4 leukemia cell lines. For leukemia patients, the positive expression rate of lrp16 mRNA in all AML patients was 38% (16/42), in which the positive rates in AML patients with complete remission (CR) and AML patients without remission were 13% (4/30) and 100% (12/12) respectively. The positive expression rate of lrp16 mRNA in ALL patients was 38% (10/26), in which the positive rate in ALL patients with CR and ALL patients without remission were 16% (3/18) and 87% (7/8) respectively. The positive expression rate of lrp16 mRNA in CML patients was 36% (9/25), in which the positive rates in CML patients with CR and CML patients without remission were 20% (4/20) and 100% (5/5) respectively. The positive rate of lrp16 mRNA in CLL patients was 31% (7/22), in which the positive rate in CLL patients with CR and CLL patients without remission were 11% (2/17) and 100% (5/5) respectively. There was no difference of lrp16 gene expression between leukemia subtypes, but there was statistical significant difference in lrp16 gene expression between CR patients and non CR patients (p < 0.001). It is concluded that the lrp16 gene is a leukemic oncogene and closely relates to genesis and progression of leukemia, which may be an indicator for evaluating clinical efficacy of leukemia therapy.
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PMID:[Lrp16 gene expression in leukemia cell lines and bone marrow cells of leukemia patients and its clinical implication]. 1969 16

Sequence variants at the TERT-CLPTM1L locus in chromosome 5p have been recently associated with disposition for various cancers. Here we show that this locus including the gene encoding the telomerase reverse-transcriptase TERT at 5p13.33 is rarely but recurrently targeted by somatic chromosomal translocations to IGH and non-IG loci in B-cell neoplasms, including acute lymphoblastic leukemia, chronic lymphocytic leukemia, mantle cell lymphoma and splenic marginal zone lymphoma. In addition, cases with genomic amplification of TERT locus were identified. Tumors bearing chromosomal aberrations involving TERT showed higher TERT transcriptional expression and increased telomerase activity. These data suggest that deregulation of TERT gene by chromosomal abnormalities leading to increased telomerase activity might contribute to B-cell lymphomagenesis.
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PMID:Deregulation of the telomerase reverse transcriptase (TERT) gene by chromosomal translocations in B-cell malignancies. 2046 May 2


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