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)

The human MUC1 gene expresses at least 2 type 1 membrane proteins: MUC1/REP, a polymorphic high m.w. MUC1 glycoprotein often highly expressed in breast cancer tissues and containing a variable number of tandem 20 amino acid repeat units, and the MUC1/Y protein, which lacks this repeat array and, therefore, is not polymorphic. Despite their documented importance in signal transduction processes, the relative expression of the 2 isoforms in epithelial tumors is unknown. Using antibody reagents which recognize different MUC1 domains, the expression of these isoforms in malignant epithelial cells has been evaluated. A comparison of the amounts of the 2 isoforms revealed preferential expression of the novel MUC1/Y protein in breast cancer tissue samples. Furthermore, although the MUC1/REP protein is almost undetectable in HeLa cervical adenocarcinoma epithelial cells, the MUC1/Y isoform is extensively expressed in these cells. The presence of the MUC1/Y sequence as well as that of an additional tandem-repeat-array-lacking isoform, designated MUC1/X, were demonstrated by reverse transcriptase PCR amplification of RNA extracted from HeLa and ovarian carcinoma cells. It has been shown previously that the MUC1 cytoplasmic domain interacts with the SH2 domain containing GRB2 protein, which transduces signals to ras, a protein which in its activated form can lead to cell transformation. We present here data demonstrating that MUC1/Y isoform expression increases the tumorigenic potential of DA3 mouse mammary epithelial cells; in contrast, potentiation of tumorigenicity is not observed with MUC1/REP expression. Our studies thus demonstrate that expression of the MUC1 gene in epithelial tumors can give rise to substantial levels of MUC1 proteins devoid of the tandem repeat array, which are generated by alternative splicing mechanisms.
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PMID:Preferential expression of novel MUC1 tumor antigen isoforms in human epithelial tumors and their tumor-potentiating function. 918 Jan 40

The aim of this study was to investigate certain genes for their suitability as molecular markers for detection of breast carcinoma cells using the reverse transcriptase-polymerase chain reaction (RT-PCR). RNA was prepared from MCF-7 breast carcinoma cells and peripheral blood leucocytes of healthy female volunteers. This RNA was screened for mRNA of MUC1, cytokeratin 19 (CK19) and CD44 (exons 8-11) by RT-PCR and the results validated by Southern blots. Variable degrees of expression of MUC1 and CD44 (exons 8-11) were detected in normal peripheral blood, rendering these genes non-specific for epithelial cells and therefore unsuitable for use as markers to detect breast carcinoma cells. Although CK19 mRNA was apparently specific, it was deemed unsuitable for use as a marker of breast cancer cells in light of its limited sensitivity. Furthermore, an attempt at using nested primers to increase sensitivity resulted in CK19 mRNA being detected after two amplification rounds in blood from healthy volunteers.
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PMID:Putative markers for the detection of breast carcinoma cells in blood. 957 23

A primary cell culture of human gastric mucous cells was developed using enzymatic treatment of surgically obtained gastric mucosal specimens. Preferential attachment of gastric mucous cells during a preincubation step resulted in the enrichment of mucous cells [over 90% stained with periodic acid-Schiff (PAS) and mucin-type lectins] in the primary cell culture. Gastric mucous cells could be maintained in culture for 10 days. DNA synthesis peaked during the first 2 days in culture (8+/-1% bromodeoxyuridine-positive cells). During the entire culture period gastric mucous cells released high-molecular-weight glycoproteins into the medium, as determined by gel chromatography on a Sepharose CL-4B column and by metabolic labelling with [14C]-N-acetylglucosamine. Gastric mucin was verified by gas chromatographic analysis of the carbohydrate composition and fractionation of the void-volume fraction by density gradient centrifugation. Determination of the terminal glycosylation of the secreted glycoproteins by a lectin-ELISA revealed that there was a high quantity of alpha-l-fucose. Prostaglandin E2 significantly stimulated glycoprotein secretion during the entire cultivation period by 29-60%. Analysis of mucin-encoding MUC mRNA expression by reverse transcriptase polymerase chain reaction revealed that gastric mucous cells predominantly express MUC1 and MUC5AC, and to a lesser extent MUC6, which reflects the expression pattern obtained following analysis of biopsied samples of gastric mucosa. This primary cell culture model enables the regulation of mucin secretion and mucin gene expression in man to be investigated.
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PMID:Morphological and molecular characterization of human gastric mucous cells in long-term primary culture. 979 1

The levels of mRNA corresponding to the MUC1, MUC2, MUC5AC, MUC5B, and MUC6 genes were determined in 19 human colon adenocarcinoma cell lines by the reverse transcriptase-polymerase chain reaction method using specific primers in an attempt to correlate to the levels of cell surface carbohydrate epitopes. All 19 cell lines expressed MUC1 and MUC5B mRNA, whereas MUC2, MUC5AC, or MUC6 mRNA were only detected in 8, 3, or 2 of 19 cell lines, respectively. Sialyl Lewis a carbohydrates, identified by the monoclonal antibody (mAb) CA19-9, and sialyl Lewis X carbohydrates. identified by mAb KM93, were observed, with most of the cell lines expressing multiple mucin core polypeptide genes but with few cell lines expressing only MUC1 and MUC5B. Sialyl Tn epitopes identified by mAb B195.3R11 and by mAb TKH-2 were strongly expressed on both of two MUC6-positive cells, whereas only a small portion of MUC6-negative cells expressed these epitopes. Strict correlation between mucin gene expression and any carbohydrate epitopes examined was not observed.
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PMID:Expression of mucin genes and carbohydrate epitopes in 19 human colon carcinoma cell lines. 1010 Jul 57

Mucus hypersecretion is characteristic of chronic airway diseases. However, regulatory mechanisms are poorly understood. Human airway epithelial cells grown on permeable supports at the air-liquid interface (ALI) develop a mucociliary morphology resembling that found in vivo. Such cultures provide a model for studying secretory cell lineage, differentiation, and function, and may provide insight regarding events leading to mucus hypersecretion. The mucin gene expression profile of well-differentiated human airway epithelial cells in culture has not yet been established. We compared expression of all the currently described mucin genes in poorly differentiated (conventional cultures on plastic) and well-differentiated (ALI) human nasal and bronchial epithelial cells. Differentiation-dependent upregulation of MUC3, MUC5AC, MUC5B, and MUC6 messenger RNA (mRNA) was demonstrated using reverse transcriptase-polymerase chain reaction (RT-PCR). Northern blot analysis showed a similar increase for MUC4 and demonstrated that induction of MUC4 and MUC5B expression depended on retinoic acid. MUC1, MUC2, MUC7, and MUC8 mRNAs were also detected by RT-PCR, but these genes did not appear to be strongly regulated as a function of differentiation. Mucin gene expression was similar in bronchial and nasal cells. Thus, mucociliary differentiation of human airway epithelia in vitro entails upregulation of several mucin genes.
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PMID:Mucin gene expression during differentiation of human airway epithelia in vitro. Muc4 and muc5b are strongly induced. 1010 Sep 90

Free cancer cells exfoliated from cancer-invaded serosa contribute to peritoneal dissemination, the most frequent pattern of recurrence in patients with gastric and ovarian cancers. This study was designed to evaluate the prognostic significance of free cancer cells in peritoneal washes detected using the reverse transcriptase-polymerase chain reaction (RT-PCR) and cytology. RT-PCR analysis with primers specific for the carcinoembryonic antigen (CEA) gene was found to be more sensitive than cytology for detection of free tumor cells in the peritoneal washes, collected at laparotomy from 199 gastric carcinoma patients, with higher detection rates for each of the T-categories in the TNM classification. Six patients with synchronous and 5 with recurrent peritoneal dissemination were found among 25 advanced cancer patients with positive PCR and negative cytology results. Positive PCR results were significantly associated with poor survival of curatively resected advanced gastric carcinoma patients (P < 0.001). A rapid method for detecting CEA mRNA using the LightCycler and the dsDNA binding dye SYBR green I was also developed. The results obtained using this technique were essentially the same as those obtained using the conventional RT-PCR method. Furthermore, RT-PCR analysis with primers specific for MUC1 epithelial mucin were performed on peritoneal washes from patients with ovarian cancer. Peritoneal washes from 21 of 25 ovarian carcinoma patients, including all 17 with positive cytology results, were positive for MUC1 mRNA, again indicating a higher sensitivity using this method than conventional cytology. Highly sensitive and rapid detection of free cancer cells in peritoneal washes, most reliably by RT-PCR, is a powerful technique to predict peritoneal dissemination in patients with gastric and ovarian cancers.
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PMID:Molecular diagnostic detection of free cancer cells in the peritoneal cavity of patients with gastrointestinal and gynecologic malignancies. 1035 56

Our goal was to determine the effect of transdermal nicotine on cytokine and mucin gene transcription in ulcerative colitis (UC). Sixty-four nonsmoking patients with active UC were randomly assigned to transdermal nicotine (maximum dose 22 mg/day) or placebo for 4 weeks. Clinical assessment and colonic mucosal biopsies were obtained at entry and after 4 weeks. Inflammatory and immunoregulatory cytokines were assessed by qualitative reverse transcriptase-polymerase chain reaction (RT-PCR). Based on this initial screen. IL-8 mRNA levels were measured by RT-competitive PCR. MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, and MUC6 mRNA concentrations were measured by quantitative dot blot analysis. Cytokine mRNA expression, except for IL-8, was similar in all patients. IL-8 mRNA levels were significantly decreased in the colonic mucosa of nicotine-treated patients who improved (p = 0.04). IL-8 mRNA values were similar before and after treatment in nonresponding nicotine-treated patients and in all placebo-treated patients. Mucin gene expression was similar in all patient groups. Beneficial effects of transdermal nicotine in active UC may result from decrease of IL-8 expression at the transcriptional level. Transdermal nicotine has no effect on mucin gene transcription.
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PMID:Transdermal nicotine decreases mucosal IL-8 expression but has no effect on mucin gene expression in ulcerative colitis. 1045 73

The expression pattern of the epithelial cell markers MUC1 (CA15-3, EMA), CA125 (OC125), human epithelial antigen HEA (Ber-EP4) and cytokeratins (Ck7, Ck8, Ck7/8, Ck8/18/19) was studied in seven human ovarian cancer cell lines. We analyzed the cell lines by immunofluorescence to determine the surface as well as cytoplasmic expression. Furthermore, we evaluated the mRNA expression of MUC1, Ck18 and Ck19 by reverse transcriptase-polymerase chain reaction (RT-PCR). All cell lines were positive for MUC1. However, expression patterns and staining intensity depended on the different epitope-specific antibodies. CA125, a typical serum marker for ovarian carcinomas, was positive only in two cell lines. HEA was strongly positive in three cell lines, whereas the others expressed the antigen only weakly in the cytoplasm. Ck7 was not expressed in three of the seven cell lines. Ck7/8 was detectable in all cell lines and was strongly expressed in four of them. MUC1 mRNA was expressed by all cell lines as detected by RT-PCR. These findings permit selection of a suitable marker for the detection of disseminated ovarian cancer cells.
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PMID:Expression of mucins and cytokeratins in ovarian cancer cell lines. 1053 Jul 81

For the advanced study of the cell and molecular biology of middle ear mucosa, an in vitro cell culture system is required. Although middle ear epithelial cells have been cultured from various species of laboratory animal, there have been no reports concerning a serial subculture system of human middle ear epithelial cells. In this paper, we describe the establishment of a primary culture system of human middle ear epithelial cells using a serum-free conditioned medium and the characterization of these cells by the expression of phenotypic characteristics of epithelial cells and mucin genes. Cultured cells were anchorage-dependent in terms of growth and showed a polygonal cobblestone-like appearance: desmosomes in the cell junction were observed by electron microscopy. In the immunocytochemical study, cytokeratin (epithelial cell marker) was expressed in all cultured cells. but von Willebrand factor (endothelial cell marker) was not. Unexpectedly, vimentin (fibroblast marker) was locally expressed, and a double stain showed the co-expression of both cytokeratin and vimentin in the same cell. The products of reverse transcriptase polymerase chain reaction from cultured cells yielded distinct bands compatible with the expected sizes of the MUC1, MUC2, MUC5AC and MUC5B genes. This culture system will allow us to prepare the cell line and to perform advanced studies of human middle ear mucosal biology.
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PMID:Mucin gene expression in cultured human middle ear epithelial cells. 1120 May 87

Mucin1 (MUCI) is a class of high molecular weight glycoproteins found in the cell membranes of human epithelial cells. Epithelial glycoprotein 40 (EGP40) is a homophilic cell-cell adhesion molecule and expressed on the surface of most simple epithelial cells and the majority of carcinomas. We analyzed the expression of MUC1 and EGP40 in human bone marrow (BM) and peripheral blood (PB) by reverse transcriptase polymerase chain reaction (RT-PCR) and immunocytochemistry (ICC). Eight BM and 95 PB samples from healthy donors, 39 BM and 17 PB samples from patients with haematological malignancies and 45 BM samples from patients with breast cancer were analyzed. MUC1 mRNA and EGP40 mRNA and protein were detected in BM samples and PB samples from healthy donors and from patients with multiple myeloma (MM), non-Hodgkin's lymphoma (NHL) and chronic myelogenous leukaemia (CML). The positive cells showed erythroblast-like and plasmacell-like morphology by immunocytochemistry. The MUC1 and EGP40 nested PCR were positive in 83.3% (10/12) and in 100% (33/33) respectively of BM from patiens with breast cancer who had no evidence of distant metastases. It is concluded that MUC1 and EGP40 is expressed in haematopoietic tissues and haematological malignancies. Therefore, MUC1 and EGP40 expression as a marker for detection of breast cancer cells and micrometastatic epithelial cells in BM and PB is not specific using RT-PCR technique and immunocytochemistry.
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PMID:Evaluation of MUC1 and EGP40 in bone marrow and peripheral blood as a marker for occult breast cancer. 1120 3


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