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

---

Query: EC:2.7.7.48 (transcriptase)
9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The adhesion molecule intercellular adhesion molecule-1 (ICAM-1), in addition to its membrane-associated form (mICAM-1), also exists as a soluble form (sICAM-1). sICAM-1 is capable of binding to lymphocyte function associated antigen-1 (LFA-1) molecules, and production of sICAM-1 is therefore thought to have immunomodulatory consequences. The present study, which employed normal human keratinocytes as a model for sICAM-1-producing cells, was conducted to determine the mechanism responsible for the production of sICAM-1 and to develop a strategy for specific inhibition of sICAM-1 production. Stimulation of keratinocytes with recombinant human gamma-interferon (rhIFN-gamma) induced both expression of mICAM-1 and production of sICAM-1. Western blot analysis revealed that keratinocyte-derived sICAM-1, compared to mICAM-1, had a smaller molecular size, approximately a 7-kD difference. Neither by Northern blot analysis nor by reverse-transcriptase polymerase chain reaction (RT-PCR) was any evidence for alternatively spliced ICAM-1 mRNA obtained. Addition of the protease inhibitors iodoacetamide and E-64, however, inhibited the production of sICAM-1 in a dose-dependent manner. The involvement of proteolytic cleavage in the production of sICAM-1 was corroborated in minimal peptide protection assays, in which minimal peptides covering the potential cleavage site of ICAM-1 were added to sICAM-1-producing keratinocytes. One of these peptides, ICAM cleavage inhibitory peptide (ICAM-CIP), inhibited the production of sICAM-1 without affecting mICAM-1 expression. These studies demonstrate that sICAM-1 production in human keratinocytes is due to proteolytic cleavage, and that the oligopeptide ICAM-CIP may specifically inhibit this mechanism. The capacity of ICAM-CIP to selectively prevent production of sICAM-1 may be useful for the development of novel therapeutic approaches relevant for the management of inflammation and cancer.
...
PMID:Analysis of the production of soluble ICAM-1 molecules by human cells. 864 65

Primary hamster tracheal surface epithelial (HTSE) cells carry mucin-like glycoproteins on the apical surface which are releasable by neutrophil elastase. In some cancer cells, mucins are localized on the cell surface and have been shown to be encoded by the MUC1 mucin gene. The objectives of the present experiments were: (I) to determine if HTSE cells express MUC1 mucin gene; (2) if they do, to isolate and characterize the hamster MUC1 complementary DNA (cDNA); and (3) to examine the pattern of MUC1 mRNA expression at different stages of culture. Reverse transcriptase-polymerase chain reaction amplification of HTSE cell RNAs using degenerate primers based on homologous sequences between the human and mouse MUC1 genes revealed the presence of a cDNA (0.5 kb) which has an 88% similarity in sequence with the mouse MUC1 cDNA. Using this 0.5 kb cDNA as a probe, an HTSE cell cDNA library was screened to isolate a hamster MUC1 cDNA clone. Sequence analysis of the cDNA revealed that it encodes an integral membrane protein of 676 amino acids which consists of (1) an N-terminal signal sequence, (2) the tandem repeat domain encoding 12 repeats of 20 amino acids, and (3) the C-terminal region consisting of degenerate tandem repeats and a unique sequence containing both the transmembrane and cytoplasmic domains. The presence of seven tyrosine residues in the cytoplasmic domain suggests a potential role as a receptor. Finally, expression of MUC1 mucin gene in HTSE cells appears to be associated with differentiation of secretory cells.
...
PMID:Expression of MUC1 mucin gene by hamster tracheal surface epithelial cells in primary culture. 870 80

The t(6;11)(q27;23) is one of the most common translocations observed in patients with acute myeloid leukemia (AML). The translocation breakpoint involves the MLL gene, which is the human homolog of the Drosophila trithorax gene, at 11q23 and the AF6 gene at 6q27. Reverse transcriptase-polymerase chain reaction (RT-PCR) using an MLL sense primer and an AF6 antisense primer detected the MLL/AF6 fusion cDNA from three leukemia patients with the t(6;11) [two AML and one T-acute lymphoblastic leukemia (ALL)] and one cell line. The fusion point in the AF6 cDNA from these cases is identical, regardless of the leukemia phenotype. The ML-2 cell line, which was established from a patient with AML that developed after complete remission of T-cell lymphoma, has retained an 11q23-24 deletion from the lymphoma stage and has acquired the t(6;11) with development of AML. The ML-2 cells have no normal MLL gene on Southern blot analysis, which indicates that an intact MLL gene is not necessary for survival of leukemic cells.
Genes Chromosomes Cancer 1996 Apr
PMID:Analysis of the t(6;11)(q27;q23) in leukemia shows a consistent breakpoint in AF6 in three patients and in the ML-2 cell line. 870 46

The breakpoints of the translocation t(2;5)(p23;q35) associated with Ki-1-positive anaplastic large cell lymphoma (Ki-1 ALCL) have recently been cloned. They involve a novel tyrosine kinase gene, ALK, at 2p23 and the nucleophosmin gene, NPM, at 5q35. Reverse transcriptase-polymerase chain reaction (RT-PCR) with NPM and ALK primers detects a consistent fusion product in Ki-1 ALCL cases that have the translocation. In the course of a survey of 15 cases of Ki-1 ALCL, we identified a single case with a slightly smaller NPM-ALK RT-PCR product, among 12 cases positive for this fusion RNA. Sequencing of this novel NPM-ALK RT-PCR product showed an in-frame junction of NPM to ALK, 30 bases distal to the usual ALK junction site, but at the usual NPM Junction site. The predicted chimeric protein in this case is thus shorter by 10 amino acids, but the putative ALK catalytic domain remains intact. PCR with ALK primers bracketing the novel fusion point, performed on either cDNA or genomic DNA, yielded the same product, confirming that this novel ALK fusion point was located within an exon. Hybridization analysis of the genomic junction fragment isolated by long-range DNA PCR suggested that the ALK genomic breakpoint was also exonic. Cloning and sequencing of the genomic breakpoint confirmed that the break occurred within the 5' portion of the ALK exon participating in the fusion junction, 28 bases 3' to the normal ALK exon boundary, resulting in the use of a cryptic splice acceptor site two bases distal to the breakpoint. This case demonstrates that, in translocations resulting in chimeric transcripts, genomic breakpoints may rarely lie within an exon, provided that the reading frame is maintained and no domains presumed critical to tumorigenesis are deleted.
Genes Chromosomes Cancer 1996 Mar
PMID:Molecular variant of the NPM-ALK rearrangement of Ki-1 lymphoma involving a cryptic ALK splice site. 872 82

A correlation between overexpression of aldehyde dehydrogenase and resistance to oxazaphosphorines, widely used anticancer agents, has been shown. To investigate the direct role of the human aldehyde dehydrogenase class 1 (ALDH-1) in the resistance to one of these agents, 4-hydroperoxycyclophosphamide (4-HC), an active metabolite of cyclophosphamide, neomycin-selectable plasmid or retroviral constructs harboring the wild-type ALDH-1 complementary DNA in the sense orientation were transfected into K562 leukemic cell lines. Polymerase chain reaction (PCR) analysis confirmed the presence of vector DNA in the stably transfected K562 cells. Reverse transcriptase PCR and Northern and Western blot analysis showed expression of ALDH-1 mRNA and protein in the cells transfected with ALDH-1 in the sense orientation but not in cells transfected with vector alone. The activity of the expressed ALDH-1 was demonstrated using spectrophotometric assay. Stably transfected K562 cells were subjected to various doses of 4-HC, and cell viability was assayed using clonogenic cell culture in semisolid medium. Results demonstrate that K562 cells transfected with ALDH-1 in the sense orientation display increased resistance to 4-HC compared with wild-type or vector-transfected K562 cells. Furthermore, the addition of diethylaminobenzaldehyde, a specific inhibitor for ALDH-1, restored the sensitivity of the ALDH-1-expressing K562 cells to 4-HC. Thus, the data pinpoint the direct role of ALDH-1 in the protection against 4-HC cytotoxicity.
Cancer Gene Ther
PMID:Overexpression of the human aldehyde dehydrogenase class I results in increased resistance to 4-hydroperoxycyclophosphamide. 878 7

We have analysed the expression of interleukin-2 receptor (IL-2R) on a panel of small-cell lung cancer (SCLC) cell lines. None of the 11 SCLC cell lines studied expressed detectable surface IL-2R alpha or beta chains by indirect immunofluorescence. Reverse transcriptase-polymerase chain reaction (RT-PCR) analyses indicated that only one out of 11 cell lines expressed detectable IL-2R beta mRNA while two expressed a weak positivity for IL-2R gamma. Five SCLC cell lines were transfected with the plasmid vector RSV.5 neo containing IL-2 cDNA coding sequence. Stable transfectants secreted biologically active IL-2 (ranging from 25 to 100 U ml-1 in the culture supernatant). IL-2 transfection did not produce significant modifications in the expression of surface molecules such as IL-2R alpha and beta chains, intercellular adhesion molecule-1 (ICAM-1), CD44, HLA class I and II or in IL-2R beta or gamma mRNA. More importantly, IL-2-transfected N592 and NCI H69 cell lines completely lost their tumorigenic potential in nude mice after subcutaneous injection, whereas experimental controls transfected with RSV.5 neo vector only, displayed an in vivo growth pattern identical to that of untransfected cells. In addition, in the N592 model, IL-2-producing N592 inhibited the growth of wild-type N592 injected at the same site, while injection of parental cells on the opposite side did not significantly affect the growth of wild-type tumour cells. Histopathological analysis of the rejection process of IL-2-transfected cells demonstrated the presence of MAC-1+, MAC-3+ macrophages and of RB68C5+ granulocytes, whereas T cells were undetectable and NK cells were scarcely represented. In addition, a reduction of the tumour blood vessels was observed. The possible relevance of these data for the development of vaccination strategies using cytokine-engineered tumour cells in SCLC is discussed.
Br J Cancer 1996 Sep
PMID:Analysis of IL-2 receptor expression and of the biological effects of IL-2 gene transfection in small-cell lung cancer. 879 83

The dissemination of cancer cells is a prerequisite in the development of micrometastases and solid metastases. Our previous examinations of these cells were based on immunocytological staining of tumor-associated antigens and cytokeratins. We have now developed a highly sensitive and specific detection method based on a nested reverse-transcriptase-polymerase-chain reaction (RT-PCR) of cytokeratin-20 (CK-20) mRNA. Using this method, we examined the bone marrow of 57 patients with colorectal cancer and detected increasing numbers of CK-20-positive samples, depending on the UICC stage. Some 35% of all bone-marrow samples tested positive for CK-20: none were found in colorectal cancer stage 1, 24% were in stage II, 31% in stage III and 71% in stage IV. Investigation of bone-marrow specimens of patients with pancreatic cancer showed that 4 out of 11 patients were positive for CK-20 mRNA. To confirm that sample positivity for CK-20 expression was due to disseminated tumor cells, we examined bone marrow from a control group (n = 16) without apparent carcinoma. In this group, 15 out of 16 donors were CK-20-negative, while one donor with familial adenomatous polyposis showed a CK-20-specific signal.
Int J Cancer 1996 Aug 22
PMID:The detection of disseminated tumor cells in bone marrow from colorectal-cancer patients by a cytokeratin-20-specific nested reverse-transcriptase-polymerase-chain reaction is related to the stage of disease. 879 68

To clarify the significance of E-cadherin gene alterations in the development of diffuse-type adenocarcinoma of the stomach, we analyzed mutations of the E-cadherin gene using the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) method followed by direct sequencing. Twenty-two signet ring cell carcinomas of the stomach (10 intramucosal and 12 advanced cancers) were examined. Genomic DNA was extracted separately from cancerous and non-cancerous tissues and PCR-SSCP analysis was performed on exons 5 to 9 and the adjacent 30- to 40-base-pair intron sequences of the E-cadherin gene. Mobility shifts were found in 2 of the 10 intramucosal cancers. In 2 of the 12 advanced cancers, abnormalities of the E-cadherin gene were observed in intramucosal lesions as well as in deeply invaded areas. These results indicated that E-cadherin gene mutations are an early event in the development of signet ring cell carcinoma of the stomach. Direct sequencing revealed that the locations of mutations of the E-cadherin gene included the branch point sequence in the intron which is responsible for RNA splicing. Reverse transcriptase-PCR demonstrated aberrant RNA splicing in a case with a branch point mutation, suggesting that branch point mutations play an important role in functional modifications of E-cadherin in signet ring cell carcinoma of the stomach.
Jpn J Cancer Res 1996 Aug
PMID:E-cadherin gene mutations in signet ring cell carcinoma of the stomach. 879 91

Hereditary nonpolyposis colorectal cancer (HNPCC) is a cancer syndrome inherited in an autosomal dominant fashion. Four susceptibility genes are known, which code for DNA mismatch repair enzymes. The purpose of this study was to identify the HNPCC gene defects in a cohort of Australian HNPCC families and to evaluate the use of RNA-based screening methods. Six mutations were identified, four in the hMLH1 gene and two in hMSH2, by using a combination of DNA-based and RNA-based methods. One of the hMLH1 defects was a missense mutation, and the other five mutations would be expected to result in a shortened protein. These included a rare type of mRNA splicing mutation in hMLH1 exon 17. By use of reverse-transcriptase (RT) PCR, defective transcripts were detectable for three of the hMLH1 mutations but not for the fourth one, which was predicted to cause skipping of exon 15. Furthermore, many more alternative transcripts for the hMLH1 gene were found than previously described, and these were more abundant in the RNA samples prepared from whole blood than from lymphoblastoid cell lines. This confounded RNA-based screening for HNPCC mutations, because it was difficult to determine which aberrant RT-PCR fragment was the real hereditary defect. One of the splice-site mutations reported here causes skipping of exons 9 and 10, which also occurs as an alternative transcript. When the protein-truncation test was used, the results were indistinguishable between the patients in this family and controls. Other aberrant transcripts were also observed that varied in size between individuals but were unrelated to the hereditary defects. This study has important implications for the design of reliable diagnostic tests for HNPCC gene defects.
...
PMID:RNA-based mutation screening in hereditary nonpolyposis colorectal cancer. 880 96

Kaposi's sarcoma (KS) accounts for more than 15% of AIDS-related malignancies. The etiology of KS is unresolved but is postulated to be multifactorial, involving viruses and overexpression of cellular growth factors and/or oncogenes. Recently, herpesvirus-like sequences (KSHV) were identified with high prevalence in AIDS-KS (AKS), endemic KS, and in classic KS biopsies (CKS). To confirm the presence and the prevalence of the KSHV sequences, 18 CKS and 13 AKS samples were tested using polymerase chain reaction (PCR) analysis. To our knowledge this is the highest number of CKS samples that has ever been included in a single study, and it is also important that the biopsies were obtained from different institutions and geographical locations. KSHV sequences were detected in 100% of the AKS samples and 72% of the CKS biopsies using PCR analysis. The presence of the unique KSHV sequences was confirmed by direct sequencing of representative PCR products obtained from AKS and CKS samples. Reverse transcriptase (RT)-PCR experiments showed that the KSHV sequences were transcribed to mRNA in both AKS and CKS samples. Our results confirm that the putative new herpesvirus-like agent is associated with both AKS and CKS and may have an etiological role in the pathogenesis of this malignancy.
...
PMID:Herpesvirus-like DNA sequences in classic Kaposi's sarcomas. 883 Jan 23


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---