Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The recent findings regarding the possible relation of prolactin to human breast cancer are reviewed. Prolactin is a single-chain polypeptide hormone secreted by the anterior pituitary; it appears important to the development and growth of mammary tumors in mice and rats. Certain drugs (L-dopa, the ergot derivatives) inhibit the release of prolactin from the anterior pituitary and lower its serum concentration. Chlorpromazine and other phenothiazines block the synthesis, release, or action of prolactin-inhibiting factors leading to increased prolactin secretion. The midcycle serum estrogen elevation does not increase serum prolactin but often high doses of estrogen will. Mammary tumors in mice and rats appear different from those in human, being of alveolar origin while human tumors are thought to be ductal. Also, rodent cancers do not usually metastasize, even when large. About 40% of human breast cancers respond to endocrine therapy while in Sprague-Dawley rats induced mammary tumors are 80% hormone responsive. In mice hyperplastic nodules but not mammary cancers respond to horomone deprivation. Prolactin is a key hormone in the stimulation of hyperplastic nodules in mice and mammary tumors in rats. The effects of progesterone on these growths is not clear. Serum prolactin levels normally vary throughout the day. Levels are not different in cancer patients but certain families with high cancer rates have been shown to have higher than normal serum levels. Although prolactin receptors have been identified in mouse and rat mammary tissue and tumors and prolactin responsiveness of the tumors correlated with the number of such receptors, these receptors have not been identified in human breast cancer cells. Patients have responded to L-dopa with relief of bone pain and a 50% decrease in serum prolactin. Suppressing atypical precancerous lesions by depriving them of their hormonal support offers the best chance for preventing eventual development of breast cancer. In vitro determination of the presence of prolactin receptors in human breast tumor tissue may allow accurate prediction of response to endocrine ablation. Variations in prolactin receptors may account for response differences of breast tumors to different doses of estrogen. Near-zero prolactin levels following hypophysectomy in some patients have been correlated with clinical remissions. Combinations of drugs to reduce serum prolactin levels or antagonize the hormones's effect on the breast may be needed to obtain results.
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PMID:Prolactin and breast carcinoma. 108 86

A protein immunologically identical to a glycoprotein antigen from fibroblast plasma membrane (SF antigen complex) is present in chicken serum. This antigen disappears from cells transformed with tumor viruses. The antigen solubilized from fibroblasts using urea and detergents, and the serum component both gave a molecular weight of about 2-10(5) as estimated by gel filtration on Sepharose 4B. Ultracentrifugation in 5-20% sucrose gradients gave a value of 7-8 S for the antigen from both sources. Isolation of antigen from serum and fibroblasts extracts was achieved using immunochemical techniques. Analysis of the polypeptide chains of the cellular antigen by electrophoresis in the presence of sodium dodecylsulphate, disclosed three major components at molecular weights 210 000 and 145 000 and 45 000. The two high molecular weight bands were identified in electrophoretograms of whole cell extracts by absorption to and subsequent elution from immunoadsorbents. The 45 000-molecular weight components comigrated with purified actin in electrophoresis. After short pulses of (35S) methionine the high molecular weight polypeptides, the 145 000-molecular weight component in particular, were among the most prominent radioactive bands from whole cell extracts indicating that SF antigen has a rapid turn-over. The antigen isolated from serum showed a polypeptide composition similar to the one from cells except the 45 000-molecular weight component was not detectable.
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PMID:Polypeptides of a glycoprotein antigen (SF) present in serum and surface of normal but not of transformed chicken fibroblasts. 109 Mar 2

Amyloidosis was induced in C57BL mice by daily injections of casein and in BALB/c mice by daily injections of endotoxin. There was no obvious disorder of immunoglobulin biosynthesis by spleen lymphocytes in these mice either before, during the development of, or in the amyloidotic stage. The pattern of immunoglobulin synthesis, assembly, and secretion was unaltered, the relative amount of heavy and light chains produced was normal, and there was an absence of immunoglobulin polypeptide chain fragments. Small amounts of amyloid were present in only 1 of 19 BALB/c and C3H mice (the IgG2a producing MOPC 173 tumor) bearing immunoglobulin-producing myeloma tumors and variants of these tumors. There was no relationship between excess light chain production by tumor plasma cells or spleen lymphocytes and the development of amyloidosis and there were no light chain fragments demonstrable. Antiserum prepared against casein-induced amyloid cross-reacted by immunofluorescence with the amyloid present in the MOPC 173 tumor-bearing mice, indicating the presence of common antigenic determinants in these two forms of amyloid. Attempts to study the biosynthesis of amyloid with incorporation of radioactively labeled amino acids were unsucessful.
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PMID:Immunoglobulin biosynthesis in myeloma-associated and casein- and endotoxin-induced murine amyloidosis. 109 61

The membrane-bound polyribosomes in Ehrlich ascites tumor cells can be separated into a loosely bound and a tightly bound fraction by means of a high salt treatment. Both membrane fractions as well as the free polyribosomes in the supernatant synthesize about the same set of proteins, suggesting a close relationship between these polyribosome fractions in the Ehrlich cell. Relatively high concentrations of cycloheximide do not prevent newly synthesized poly(A)-containing mRNA from entering the tightly bound polyribosome fraction. Nor had treatment of the cells with puromycin in the presence of cycloheximide, which released about 70% of the nascent chains, any significant effect on the entrance of newly synthesized mRNA into tightly bound polyribosomes. These results suggest that in ehrlich ascites tumor cells nascent polypeptide chains are not involved in the binding of polyribosomes to membranes.
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PMID:Transport of messenger RNA into different classes of membrane-associated polyribosomes in Ehrlich-ascites-tumor cells. 123

Until five years ago, it was believed that the oligosaccharide chains of most, if not all, glycoproteins were assembled by the stepwise transfer of single sugar residues from their nucleotide derivatives to growing oligosaccharide chains attached to a polypeptide core. It is now becoming widely accepted that polyisoprenol-linked mono- and oligosaccharides function as activated glycosyl carriers in the biosynthesis of some glycoproteins in animal tissues. The lipophilic glycosyl carrier of monosaccharides is the phosphomonoester of dolichol, the C(80-100)-polyisoprenol, containing a saturated terminal isoprene unit. In this biosynthetic process, sugars are initially transferred to dolichol monophosphate from their nucleotide derivatives by membrane-associated glycosyltransferases. These dolichol-linked monosaccharides serve as glycosyl donors in the glycosylation of oligosaccharide phospholipids. It appears likely that dolichol is also the lipid moity of the oligosaccharide intermediates. Detailed enzymatic studies with oligosaccharide phospholipids formed by rat liver, a mouse myeloma tumor and hen oviduct have revealed that these intermediates function as oligosaccharide donors in the assembly of at least one class of glycoproteins. The exact nature of the glycoproteins glycosylated by lipid intermediates and the sub-cellular site(s) of this assembly process remain to be established. The possibility, that the mannose and GlcNAc-containing core found in many glycoproteins, is assembled at the lipid-level is now being investigated. At the current rate of progress in this area of research, the identity of the glycoproteins glycosylated via lipid intermediated and the subcellular site of this assmebly process will soon be known.
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PMID:Polyisoprenoid glycolipids involved in glycoprotein biosynthesis. 127 57

The leukocyte integrin alpha 4 beta 1 (VLA-4, CD49d/CD29) is a receptor for the extracellular matrix protein fibronectin and the endothelial adhesion protein VCAM-1. We have analyzed the biosynthesis and post-translational modifications of the two subunits of this receptor complex. The alpha 4 subunit was initially synthesized as a single-chain polypeptide that underwent the formation of complex endoglycosidase H-resistant oligosaccharide side chains and which could be proteolytically cleaved into two noncovalently associated fragments. The level and rate of alpha 4 subunit cleavage was dependent on the cell studied. The T cell tumor line HPB-ALL expressed both intact and fragmented alpha 4 on the cell surface. The interleukin-2-dependent natural killer line NK 3.3 and long term interleukin-2-dependent activated T lymphocytes cleaved the alpha 4 polypeptide earlier and more efficiently than did HPB-ALL cells and did not have detectable levels of intact alpha 4 on the cell surface. The proteolysis of alpha 4 was blocked by treating cells with either the lysosomotrophic amine NH4Cl or the carboxylic ionophore monensin. The presence of complex N-linked oligosaccharides did not seem to be necessary for alpha 4 cleavage or for binding of the alpha 4 beta 1 complex to a synthetic peptide corresponding to the binding site for this receptor on fibronectin.
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PMID:Post-translational processing of the leukocyte integrin alpha 4 beta 1. 128 Nov 55

Among the members of the cytokeratin (CK) subfamily of intermediate filament (IF) proteins, CK 17 is remarkable as it is normally expressed in the basal cells of complex epithelia but not in stratified or simple epithelia. Because of its unusual expression pattern in normal and diseased states and because of the potential importance of CK 17 in tumor diagnosis, we have characterized the gene(s) and its cDNA-derived amino acid sequence. A cDNA clone encoding CK 17 was isolated from a HeLa cDNA library and used for the determination of the amino acid sequence, for studies of expression and for the screening of human genomic libraries. A number of lambda phage clones were isolated that covered three distinct, non-contiguous gene regions. Only one of these loci contains the functional CK 17 gene which is located only approximately 5 kbp 5'-upstream of the CK 16 gene, whereas the other two contain unprocessed CK 17 pseudogenes. Each of these genes is part of a larger CK type I gene locus the arrangement of which suggests that these genes and pseudogenes have arisen during evolution by duplication events comprising whole multigene loci. The functional CK 17 gene differs from the pseudogenes by the extent of methylation of certain DNA sequences in the 5'-upstream region. The 5 kbp CK 17 gene with 8 exons and 7 introns encodes a polypeptide of 432 amino acids with a calculated molecular weight of 48,000. Using S1-nuclease protection assays and RNAs from several cell lines we identified a single transcriptional start point 26 nucleotides down-stream from a TATA box element. Northern blot hybridization experiments showed a restricted pattern of CK 17 gene expression, supporting the notion that CK 17 synthesis is essentially regulated at the transcriptional level. From these findings and from immunohistological observations, CK 17 synthesis seems to be a marker of basal cell differentiation in complex epithelia and therefore indicative of a certain type of epithelial "stem cells".
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PMID:Characterization of the human gene encoding cytokeratin 17 and its expression pattern. 128 71

The mitogenic and chemotactic potency of platelet-derived growth factor (PDGF) has linked this polypeptide to the pathogenesis of several disease states including atherosclerosis and neoplasia. We have reviewed the recent literature on aspects relating to the structure, distribution and biology of PDGF and its high-affinity cell-surface and intracellular receptors. In addition to platelets, several normal and tumor cells secrete the mitogen in one or more of three possible dimeric configurations. Alternative splicing of exon 6 in PDGF A-chain RNA results in the formation of two protein species with different carboxy-termini. Initially, it was thought that the longer A-chain variant was processed only by transformed cells. However, recent evidence indicates that alternative splicing occurs in several cells which express the A-chain, including early Xenopus embryos. The functional significance of the exon 6 product, a highly basic region spanned by 18 amino acid residues (A194-211), is not precisely clear. We have summarized recent findings which implicate roles for A194-211 in the processing, secretion, and mitogenesis of the A-chain homodimer, nuclear transport signalling, and heparin binding. Thus, alternative splicing could play an important role in the modulation of the functional properties of the PDGF A-chain variants per se and in the complex interactive network of polypeptide growth factors and cytokines.
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PMID:Platelet-derived growth factor and alternative splicing: a review. 128 70

Serum tissue polypeptide antigen (TPA) was determined in 86 cirrhotic patients who underwent a thorough clinical and laboratory evaluation. Increased serum TPA levels were found in 87.2% of the patients (81% of Child's A, 81.3% of Child's B and 97% of Child's C) with very high levels in some cases. There were significant correlations between TPA and several clinical and biochemical tests, especially AST (r = 0.678, p < 0.000001), and this enzyme was the best predictor of TPA levels. Patients with abnormal AST had also significantly higher serum levels of TPA than those with normal AST in each of the Child's class (p < 0.01 for each). TPA values were found to be more frequently abnormal than AST ones in cirrhotics (p = 0.009) and could be used as indirect markers of activity in these patients. The underlying mechanism involved in the increase in TPA in cirrhosis was probably related to the cytolytic/regenerative activity of the liver. TPA cannot be used as a tumor marker in these patients.
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PMID:A clinical and laboratory evaluation of the behavior of tissue polypeptide antigen in liver cirrhosis. 129 4

The identification of unique Marek's disease (MD) virus (MDV) antigens expressed not only in lytically infected cells but also in latently infected MD lymphoblastoid tumor cell lines is important in understanding the molecular mechanisms of latency and transformation by MDV, an oncogenic lymphotropic herpesvirus of chickens. Through cDNA and nucleotide sequence analysis, an open reading frame (designated the pp38 ORF) which encodes a predicted polypeptide of 290 amino acids was identified in BamHI-H. Demonstration that the pp38 ORF spans the junction of the MDV long unique and long internal repeat regions (MDV has an alphaherpesvirus genome structure) precludes the presence of the gene encoding the B-antigen complex (gp100, gp60, and gp49) in the same region of BamHI-H, where it was originally thought to exist. Duplication of the complete pp38 ORF was not observed in BamHI-D, but part of it (encoding 45 amino acids) was found in the long terminal repeat region of the fragment. By use of trpE-pp38 fusion proteins, antisera against pp38 were prepared. By immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a predominant virus-specific 38,000-dalton polypeptide (designated pp38) and a minor 24,000-dalton polypeptide (designated p24) were found. No precursor-product relationship was found between pp38 and p24 by pulse-chase analysis, and only pp38 was detected by Western blot (immunoblot) analysis with antiserum to pp38. pp38 was found to be phosphorylated and present in oncogenic serotype 1-but not nononcogenic serotype 3-infected cells. Expression of the gene encoding pp38 was relatively insensitive to phosphonoacetic acid inhibition, suggesting that pp38 may belong to one of the early classes of herpesvirus proteins. pp38 was also detected in the latently infected MSB-1 lymphoblastoid tumor cell line. The detection of antibody against pp38 in immune chicken sera indicates that pp38 is an immunogen in birds with MD. Most of the properties described here for a protein detected by methods based on finding the ORF first are identical to those of a 38-kDa phosphoprotein reported by others, suggesting that they are the same. Collectively, the data reported here provide (i) more definitive information on the complete ORF of another MDV gene and the protein that it encodes, (ii) clarification of the gene content within a specific region of the MDV genome, and (iii) the molecular means to conduct further studies to determine whether pp38 plays a role in MDV latency and transformation.
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PMID:Identification of a unique Marek's disease virus gene which encodes a 38-kilodalton phosphoprotein and is expressed in both lytically infected cells and latently infected lymphoblastoid tumor cells. 130 66


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