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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The analysis has been made of the literary and the author's own experimental evidences on the antigenic diversion of tumor cells resulting from the expression of hetero-organic antigens, which is one of the most characteristic manifestations of disturbance of cytodifferentiation in carcinogenesis. Studies of hepatocellular tumors and liver of rats subject to single hepatocarcinogen injections being exemplified, the author considers some cases of detection of hetero-organic antigens of kidney origin in the cytosol, on the outer cell membranes and within the chromosomal non-histone proteins (NHP). Under discussion is the interrelation between the expression of hetero-organic antigens, attributed to the same tissue type in different cell structures, and a possible role of NHP as factors directing the disdifferentiation of neoplastically transformed cells.
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PMID:[The antigenic divergence of tumor cells due to the expression of hetero-organic antigens as a manifestation of disordered differentiation in carcinogenesis]. 227 13

Cell cycle-regulated gene expression is essential for normal cell growth and development and loss of stringent growth control is associated with the acquisition of the transformed phenotype. The selective synthesis of histone proteins during the S phase of the cell cycle is required to render cells competent for the ordered packaging of replicating DNA into chromatin. Regulation of H4 histone gene transcription requires the proliferation-specific promoter binding factor HiNF-D. In normal diploid cells, HiNF-D binding activity is regulated during the cell cycle; nuclear protein extracts prepared from normal cells in S phase contain distinct and measurable HiNF-D binding activity, while this activity is barely detectable in G1 phase cells. In contrast, in tumor-derived or transformed cell lines, HiNF-D binding activity is constitutively elevated throughout the cell cycle and declines only with the onset of differentiation. The change from cell cycle-mediated to constitutive interaction of HiNF-D with the promoter of a cell growth-controlled gene is consistent with, and may be functionally related to, the loss of stringent cell growth regulation associated with neoplastic transformation.
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PMID:Tumor cells exhibit deregulation of the cell cycle histone gene promoter factor HiNF-D. 232 Oct 7

We have investigated the expression of the H1 histone subtype H1(0) gene in Ehrlich ascites tumor cells (EAT) under varied conditions of oxygen supply. Our results show that proliferating EAT cells express H1(0) mRNA at a basal level under normoxic conditions. Severe hypoxia leads to a cessation of cell growth and causes an accumulation of cells in G1. Here, we show that the level of H1(0) histone mRNA increases within a few hours after the onset of hypoxia.
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PMID:Increased level of histone H1(0) messenger RNA in hypoxic Ehrlich ascites tumor cells. 232 74

A non-histone protein with mol. wt of 48,000 differentially expressed in normal and tumour cells was identified using immunological criteria. Antibodies were raised against a component specific for Kirkman-Robbins hepatoma of mol. wt about 48,000 separated from hepatoma non-histone proteins by preparative electrophoresis in polyacrylamide gel. It was demonstrated by immunoblotting that Morris hepatoma 7777 and Ehrlich ascites cells share an antigenic non-histone protein with Kirman-Robbins hepatoma. Tumour cells when compared with normal cells, i.e. hamster and rat liver, are characterized by significant enrichment of this component. Intracellular distribution of the polypeptide with mol. wt 48,000 suggests that this component may be a structural protein the biosynthesis of which increases or the antigenic determinants of which change in tumour cells.
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PMID:Identification of a nuclear antigen with molecular weight of 48,000 differentially expressed in tumour and normal cells. 235 Aug 66

Rates of histone phosphorylation were measured in explants of mammary glands from mouse strains with high and low tumor incidence. Explants of hormone dependent and independent mouse mammary tumors were also investigated. All mouse strains studied showed predominant phosphorylation of H2A histone at serine and threonine residues. No differences in rates of H2A phosphorylation in glands were found between strains having different mammary tumor susceptibility. Hormone-dependent GR mouse mammary tumors also showed high H2A phosphorylation, but in some tumors also H1 and H3 were phosphorylated. Hormone-dependent GR tumors had 2-5 times higher histone phosphorylation at serine and threonine than hormone-independent tumors.
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PMID:Histone phosphorylation in explants of mouse mammary glands and tumors. 243 73

Lipid content and composition of DNA, histone and non-histone proteins of Ehrlich ascites tumor cell chromatin were investigated. All fractions contained small amounts of lipids, mostly neutral ones, in a specific distribution. According to isotopic studies with labeled lipid precursors, incorporation took place mainly in the non-histone fraction. These findings suggest that neutral lipids attached to non-histone chromosomal proteins may also contribute to the regulatory functions ascribed to phospholipids.
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PMID:Lipids as integral constituents of nuclear and chromatin fractions in Ehrlich ascites tumor cells. 244 69

Neutral amino acid transport by system A was investigated in the epithelial cell lines MDCK and MDCK-T1. The latter line is a chemically induced, oncogenically transformed line derived from MDCK. Inducers of differentiation, sodium butyrate and 5-azacytidine, and a tumor promoter, TPA, were used as probes to delineate pathways of regulation involved in system A response to a variety of physiological conditions and agents. Azacytidine, an inhibitor of DNA methylation, and butyrate, an enhancer of histone acetylation, inhibited expression of system A, had little effect on system ASC, and slightly stimulated system L. Inhibition of system A expression by butyrate and azacytidine occurred under different conditions. Increases in system A activity due to amino acid starvation or transformation were inhibited by butyrate but not by azacytidine. Repressed system A activity, normally observed in the presence of high levels of amino acids, was more sensitive to azacytidine than to butyrate. The tumor promoter, TPA, stimulated system A activity in MDCK cells under normal growth conditions but did not stimulate activity in amino acid-starved MDCK cells or in MDCK-T1 cells. Stimulation of system A activity by TPA was prevented by prior exposure to butyrate but not to azacytidine. These results suggest 1) that system A expression observed in growing amino-acid-repressed MDCK cells is modulated by an azacytidine-sensitive mechanism and 2) that the elevated expression of system A activity induced by amino acid starvation, by chemical transformation to MDCK-T1, and by TPA is modulated by a butyrate-sensitive mechanism.
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PMID:Effects of 5-azacytidine, sodium butyrate, and phorbol esters on amino acid transport system A in a kidney epithelial cell line, MDCK: evidence for multiple mechanisms of regulation. 245 37

Nuclear proteins were extracted from purified nuclei of 7,12-dimethylbenz(a)anthracene(DMBA)-induced tumors and normal mammary glands of the rat by enzymatic treatment. Of the 34 bands indicated by one-dimensional polyacrylamide gel electrophoresis of nuclear proteins, 6 appeared in high concentration in tumors but were found as traces or undetectable in normal glands; 6 others were clearly shown in the latter but were not detectable or greatly reduced in the former. Two-dimensional electrophoresis identified about 130 and 92 non-histone proteins in normal mammary and tumor cell nuclei respectively. Marked differences in spot density were noted especially in spots (M.W. X 10(-3)/pI) 100/5.7 and 200/5.5 of tumors and 28/7.1, 32/5.4, 36/5.4, 38/6.9, and 68/6.0 of normal tissue. The relationship between these nuclear proteins and the development of mammary tumors is also discussed.
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PMID:Comparison of nuclear proteins from DMBA-induced mammary tumors and lactating mammary glands by polyacrylamide gel electrophoresis. 257 94

The purpose of this investigation is to give an introduction to a novel method in tumor pathology, namely the Ag-NOR technique. The basis of this method is the argyrophilic staining of intranucleolar, non-histone proteins which are specifically associated with transcriptionally active sites of ribosomal DNA. They can therefore be considered as a marker for the protein synthesis and thus the proliferation rate of a given cell. The morphologic basis of the argyrophilic reaction is presented by metaphasic and interphasic tissue culture cells. The applicability of Ag-NOR technique to tumor pathology is exemplified by main results of three studies dealing with tissue sections of 65 meningiomas, whole organ sections of 50 renal carcinomas, and cytospin preparations of 30 urinary washout specimens. These studies document the considerable value of the Ag-NOR content for both, malignancy diagnosis and tumor grading. With the help of image analysis it can be shown that besides the mean number of Ag-NORs the mean area per Ag-NOR dot is of diagnostic significance. In conclusion the Ag-NOR technique is a simple inexpensive and accurate method which can be applied both to formalin fixed, paraffin-embedded tissue and cytologic specimens. As a marker of malignancy it is an invaluable new tool for the diagnostic pathologist.
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PMID:Nucleolar organizer regions (NORs). Basic concepts and practical application in tumor pathology. 261 72

Protein kinase C, which plays a significant role in the polyphosphoinositide pathway of transmembrane signaling, is activated by a large class of extracellular ligands including neurotransmitters, hormones and growth factors. Diacylglycerols are the intracellular mediators of protein kinase C activation. Tumor promoting phorbol esters mimic the diacylglycerol action in binding to the same site. Active diacylglycerols have the 1.2 sn configuration and saturated short chain or unsaturated long chain fatty acids. Alkyl analogs of diacylglycerols were devoid of activity when an ether bond was present in position 1, whereas activity of the alkyl analog in position 2 was retained. Protein kinase C activation and 3H-TPA binding to the enzyme occurred in the presence of 0.5 mM EGTA. Moreover it has been shown in vivo that full activation of the enzyme was obtained in the intact platelets loaded with an excess of Quin 2, prior to stimulation by phorbol esters. A peptide (residues 499-513) was synthesized which enhanced the affinity of protein kinase C for histone. It is suggested that it may be the receptor site for another peptide of the enzyme (residues 19 to 36) which behaves as a pseudosubstrate.
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PMID:[The role of calcium, diglyceride ester bindings and a synthetic polypeptide in protein kinase C activation]. 262 74


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