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

We sought to determine whether the hepatocyte growth factor/scatter factor (HGF/SF)- and keratinocyte growth factor-receptor systems were expressed in normal breast cells, breast carcinoma cell lines, normal breast tissues, and breast cancer tissues. Reverse transcriptase-polymerase chain reaction and hot blotting were used to detect HGF, HGF/SF (met) receptor, KGF, and KGF receptor mRNAs in human mammary epithelial (HME) and stromal (HMS) cells. We also examined breast carcinoma (MDA-MB-157, SCC 38, and SCC 70) and spontaneously immortalized breast epithelial (HMT 3522) cell lines, as well as normal breast and breast carcinoma tissues. PCR products were also confirmed by nucleic acid sequencing. The effects of HGF and KGF, compared to EGF and heparin-binding EGF, on the proliferation of normal human mammary epithelial cells in serum-free defined medium was determined by cell counting. HGF and KGF mRNAs were detected in HMS cells, but not HME cells. KGF receptor mRNA was detected in HME cells, but not HMS cells. HGF/SF receptor mRNA was detected in both HME and HMS cells. mRNAs were also detected in normal breast and breast carcinoma tissues, as well as breast carcinoma and transformed breast epithelial cell lines. Alternative cDNA sequences that are predicted to code for a soluble KGF receptor and a membrane bound, truncated HGF/SF receptor were detected in breast epithelial cells and breast tissues. HGF and KGF maintained viability and stimulated proliferation of HME cells.
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PMID:Hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), and their receptors in human breast cells and tissues: alternative receptors. 786 34

Within the hematopoietic lineage, the monoclonal antibody (MoAb) CD66 reacts with cells of the granulocyte lineage, but not with the majority of progenitor cells from human bone marrow. Our previous studies have shown that CD66 binds specifically to at least three carcinoembryonic antigen (CEA) superfamily members, ie, CEA itself, nonspecific cross-reacting antigen (NCA), and CGM1, but not to CGM6 (NCA-95). In this report, we show that CD66 will also identify the biliary glycoproteins (BGP). A full-length cDNA for the BGPc molecule (a cytoplasmic splice variant of BGPa) was isolated by expression cloning using the CD66 MoAbs. This protein has an identical extracellular and transmembrane sequence to BGPa with one N-terminal IgV like domain, three IgC-like extracellular domains (A1, B1, and A2), plus a transmembrane domain, but the cytoplasmic domain is spliced by 53 nucleotides. Reverse transcriptase-polymerase chain reaction experiments show that this splice variant can be detected in colonic carcinoma cell lines, in primary colonic adenocarcinomas, and in myeloid and B-cell lines to varying degrees. Quantitative analyses of BGPc RNA expression by RNase protection indicate that abundant levels occur only in the colonic, but not in the hematopoietic, cell lines tested. Studies presented here show that BGPc mediates homotypic adhesion and suggest that the cytoplasmic splicing does not alter the initial homotypic adhesion properties of BGPa.
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PMID:CD66 identifies the biliary glycoprotein (BGP) adhesion molecule: cloning, expression, and adhesion functions of the BGPc splice variant. 801 19

A novel immunomodulator, imiquimod, has been shown to be an effective topical antiviral and antitumor agent in animal models. Imiquimod has been reported to induce interferon-alpha and other cytokines in animals and humans, but its precise role as an immunomodulator at skin sites has not been determined. We investigated its effect on cytokine gene expression in the human epidermal carcinoma cell line COLO-16 and human keratinocytes. COLO-16 cells were incubated with imiquimod (1 and 10 micrograms/ml) and human keratinocytes with 5 micrograms/ml for 6 or 24 h. Cytokine gene expression was analyzed by reverse-transcriptase PCR. In COLO-16 cells, imiquimod stimulated IL-6 mRNA levels 2.3- and 4.4-fold at 1 and 10 micrograms/ml after 6 h. IL-8 mRNA increased 4-fold at both 1 and 10 micrograms/ml. At 24 h, though IL-6 mRNA level at 1 micrograms/ml was further stimulated, enhanced expressions of IL-8 at 1 micrograms/ml and both IL-6 and IL-8 at 10 micrograms/ml were down-regulated. In human keratinocytes, 5 micrograms/ml of imiquimod stimulated IL-6 mRNA levels 1.4-fold at 6 h and 2.1-fold at 24 h, and IL-8 mRNA levels 1.7- and 2.0-fold at 6 and 24 h. IL-1 alpha mRNA levels in COLO-16 or keratinocytes were unchanged by either dose or incubation time. These results suggest that stimulation of IL-6 and IL-8 expression may be involved in the immunomodulating action of imiquimod.
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PMID:Effects of a novel topical immunomodulator, imiquimod, on keratinocyte cytokine gene expression. 806 Nov 17

Paraneoplastic encephalomyelitis developed as the presenting feature of small-cell lung carcinoma in 3 patients. Two patients with paraneoplastic encephalomyelitis manifested predominantly as subacute sensory neuronopathy did not improve after prednisone treatment and chemotherapy. The third patient had severe axial and limb rigidity and myoclonus, which partially improved after chemotherapy and treatment with intravenous immunoglobulin and prednisone. Serum from each patient immunocytochemically stained the neuropil and to a lesser degree the neuronal cytoplasm in human cerebral and cerebellar cortex. On immunoblots of human neuronal extracts, each patient's serum contained high-titer IgG antibodies reacting with a protein band of apparent molecular mass 125 kd. This autoantibody pattern is indistinguishable from antibodies recently identified in several women with breast carcinoma and stiff-man syndrome. Screening of a human brain complementary DNA expression library with patient serum yielded clones whose sequence is identical to that of the synaptic vesicle-related protein amphiphysin. Reverse transcriptase-polymerase chain reaction demonstrated expression of amphiphysin in 8 of 10 small-cell lung carcinomas and in 5 of 14 breast carcinomas. These observations highlight the clinical and serological heterogeneity of paraneoplastic central nervous system disorders: Patients with a given clinical syndrome may have different antineuronal antibodies, and patients with a given autoantibody specificity have differing clinical presentations.
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PMID:Antiamphiphysin antibodies with small-cell lung carcinoma and paraneoplastic encephalomyelitis. 861 52

We previously established transplantable rat thyroid carcinoma cell lines in vivo from primary thyroid tumors induced by N-bis-(2-hydroxypropyl)nitrosamine (DHPN). In the present study, an insulin-like growth factor I (IGF-I)-responsive cell line (TRTC-G1-C-A4) in culture was derived from one (well differentiated papillary type) of these carcinoma cell lines G1. TRTC-G1-C-A4 cells were found to exhibit specific saturable binding of IGF-I with a Kd of 1.16 nM at approximately 43.6 fmol/10(5) cells. Inclusion of IGF-I (10 and 50 ng/ml) in the culture medium resulted in a significant increase of [3H]thymidine incorporation and marked cell proliferation. IGF-II (10 ng/ml) and insulin (1 microgram) produced no such effects. The molecular weight of IGF-I receptors on the cell membrane was determined by Western blotting analysis, a single band of binding proteins with a molecular weight of 125 kDa being evident under non-reducing conditions. Reverse transcriptase polymerase chain reaction (RT-PCR) showed that the TRTC-G1-C-A4 cells contained IGF-I receptor mRNA with a sequence corresponding to that determined from rat uterus. These results demonstrate that the IGF-I receptor can be expressed in a thyroid carcinoma with an important contribution to cell growth.
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PMID:Establishment of a rat thyroid carcinoma cell line in vitro demonstrating high DNA synthesis in response to insulin-like growth factor I. 862 Apr 77

To further investigate the possibility for retroviral involvement in the etiology of human breast cancer we processed peripheral blood monocytes and malignant breast tissue biopsies from 10 patients with breast cancer (infiltrating ductal carcinoma or infiltrating lobular carcinoma; ages 40-80 years) and 20 normal healthy women (with no evidence or family history of breast cancer. 10 age-matched controls and 10 women age 22-27 years) for the assay of the retroviral enzyme, reverse transcriptase, using an ELISA and for election microscopy examination for the detection of retroviral-like particles. Reverse transcriptase activity was detected in 5 out of 10 samples of monocyte culture medium and in 1 out of 10 of malignant tissue biopsies from the patients with breast cancer. In contrast, reverse transcriptase was not detected in the culture medium of the monocytes from any of the control subjects. Electron microscopy did not reveal the presence of any retroviral-like particles in any sample of monocyte culture medium or in any of the malignant or normal breast tissue biopsies. Despite evidence for the presence of reverse transcriptase in a subsample of the monocyte culture medium and breast tissue biopsies from the cohort of breast cancer patients who participated in this study, the role of retroviruses in human breast cancer remains unclear.
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PMID:Are retroviruses involved in the aetiology of human breast cancer? 863 60

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.
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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

Chinese hamster ovary cells (CHO cells) do not exhibit any Ca2+/calmodulin-stimulated cAMP phosphodiesterase (PDE1) activity. Challenge of CHO cells with agonists for endogenous P2-purinoceptors, lysophosphatidic acid receptors and thrombin receptors caused a similar rapid transient induction of PDE1 activity in each instance. This was also evident on noradrenaline challenge of a cloned CHO cell line transfected so as to overexpress alpha 1B-adrenoceptors. This novel PDE1 activity appeared within about 15 min of exposure to ligands, rose to a maximum value within 30 min to 1 h and then rapidly decreased. In each case, the expression of novel PDE1 activity was blocked by the transcriptional inhibitor actinomycin D. Challenge with insulin of either native CHO cells or a CHO cell line transfected so as to overexpress the human insulin receptor failed to induce PDE1 activity. Reverse transcriptase-PCR analyses, using degenerate primers able to detect the PDE1C isoform, did not amplify any fragment from RNA preparations of CHO cells expressing PDE1 activity, although they did so from the human thyroid carcinoma FTC133 cell line. Reverse transcriptase-PCR analyses, using degenerate primers able to detect the PDE1A and PDE1B isoforms, successfully amplified a fragment of the predicted size from RNA preparations of both CHO cells expressing PDE1 activity and human Jurkat T-cells. Sequencing of the PCR products, generated using the PDE1A/B primers, yielded a novel sequence which, by analogy with sequences reported for bovine and murine PDE1B forms, suggests that the PDE1 species induced in CHO cells through protein kinase C activation and that expressed in Jurkat T-cells are PDE1B forms.
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PMID:Receptor-mediated stimulation of lipid signalling pathways in CHO cells elicits the rapid transient induction of the PDE1B isoform of Ca2+/calmodulin-stimulated cAMP phosphodiesterase. 900 15

Cells of two human follicular thyroid carcinoma cell lines (FTC133, FTC236) were stably transfected with a cDNA encoding the PDE4A cAMP-specific phosphodiesterase (PDE) splice variant RD1 (RNPDE4A1A) so as to generate the cloned cell lines, FTC133A and FTC236A. This allowed the expression of a novel rolipram-inhibited cAMP-specific PDE activity in these cells. Unlike the parent cell lines in which Ca2+/calmodulin caused a profound activation (approx. 3-4-fold) of homogenate PDE activity, no such stimulation was evident in the RD1-expressing cell lines, indicating loss of PDE1 activity. Reverse transcriptase-PCR analysis indicated that this was due to the down-regulation of the PDE1C isoform. The novel PDE4 activity in transfected cells was located exclusively in the membrane fraction, as was immunoreactive RD1. Low concentrations of the detergent Triton X-100, but not high NaCl concentrations, allowed RD1 to be solubilized. Laser scanning confocal immunofluorescence analyses identified RD1 immunoreactivity in a discrete perinuclear region of these RD1-expressing transfected cell lines. A similar pattern of labelling was observed using the antiserum Tex1, which specifically identified the Golgi apparatus. Treatment of FTC133A cells with the Golgi-perturbing agents monensin and brefeldin A led to a similar redistribution of immunoreactive species detected using both the Tex1 and anti-RD1 antisera. It is suggested that the PDE4A splice variant RD1 contains a membrane-association signal which allows the targeted expression of RD1 within the Golgi complex of these human follicular thyroid carcinoma cell lines.
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PMID:Intracellular localization of the PDE4A cAMP-specific phosphodiesterase splice variant RD1 (RNPDE4A1A) in stably transfected human thyroid carcinoma FTC cell lines. 900 17

The expression and activity of aromatase was evaluated in 19 individuals with benign prostatic hyperplasia (BPH) and 26 prostatic carcinoma (PC) patients to elucidate the possible biological significance of in situ estrogen production in the development of human prostatic disorders. Marked aromatase immunoreactivity was observed in proliferative stromal cells, especially those around hyperplastic glands in 18 (95%) BPH patients and in stromal cells surrounding carcinomatous glands in 18 (69%) PC patient specimens. The percentage of aromatase-positive stromal cells did not differ between BPH and PC. No significant correlation was apparent between the percentage of aromatase-positive cells and either the extent of carcinoma differentiation or surgical stage in the PC patients. Quantitation of aromatase activity by the [3H] water assay yielded values of 27.23 +/- 6.87 and 26.52 +/- 9.12 fmol/hr/mg of protein for BPH (nine patients) and PC (nine patients), respectively. Reverse transcriptase and polymerase chain reaction analysis revealed that the mean aromatase mRNA content was 1.671 +/- 0.82 and 1.11 +/- 0.51 attomole/ng of total RNA (tRNA) for BPH (seven patients) and PC (four patients), respectively. There were no significant differences in aromatase activity or aromatase mRNA concentration between PC and BPH. The alternative use of multiple exons 1 of the aromatase gene was also examined. Predominant aromatase gene transcripts contained exon 1b in three of four of PC specimens and two of three BPH specimens examined, in contrast to the use of exon 1d previously described in normal prostate. Unlike breast and endometrium, therefore, aromatase expression in human prostate was not associated with malignancy. However, overexpression of aromatase, possibly attributable to abnormal gene regulation, may result in estrogen production in situ and play a role in the induction or development of human prostatic disorders.
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PMID:Aromatase in hyperplasia and carcinoma of the human prostate. 914 Jan 25


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