Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum removal from the media of serial monolayer cultures of the Harding-Passey melanoma during an incubation period of 3 days resulted in an exponentially declining DNA synthesis rate (measured by the incorporation of [14C]thymidine) and in an inhibition of cell proliferation. Protein synthesis, as measured by the incorporation of radioactive leucine, was less affected than DNA synthesis. Incubation in serum-free culture medium resulted in significant rises of tyrosinase activity and cellular melanin content. Addition of dibutyryl adenosine 3':5' monophosphate (Bu2cAMP, 5X10(-4) M) and theophylline (5X10(-4) M) to serum-free cultures caused a further striking increase of tyrosinase activity and melanin formation, while treatment of serum containing cultures with Bu2cAMP and theophylline showed only a slight rise in melanogenesis. It is suggested that these stimulatory effects are mediated by an increased intracellular cAMP level, since a correlation between the degree of melanogenesis and cellular cAMP content was indicated. Treatment of serum-free or serum-containing cultures with the phosphodiesterase inhibitor theophylline (5X10(-4)--10(-3)M) alone revealed only a slight enhancement (about 20%) of melanogenesis. Because augmentation of melanogenesis by serum-free medium alone or together with Bu2cAMP and theophylline was prevented by cycloheximide (or actinomycin D), de novo protein synthesis seems to be required for these stimulatory effects.
 ...
PMID:Stimulation of tyrosinase activity and melanin formation of cultured melanoma cells by serum deprivation alone or in combination with dibutyryl cyclic AMP and theophylline. 19 88

DBcAMP reversibly arrests cultivated Cloudman melanoma cells in the late S and G2 phases of the cell cycle. This is supported by the measurement of DNA synthesis by autoradiography and measurement of cellular DNA by two methods--the diphenylamine reaction and microspectrophotometry of Feulgen stained cells. We also present evidence that (1) cell division is prevented if DBcAMP is added as late in the cycle as early S phase. (2) The inhibition of cell division does not appear to be caused by products of tyrosine oxidation. (3) The increase in cell size that occurs in the presence of DBcAMP reflects continued synthesis of protein in the absence of cell division.
 ...
PMID:Dibutyryl cyclic AMP arrests the growth of cultivated Cloudman melanoma cells in the late S and G2 phases of the cell cycle. 20 51

Most humans in the United States have been infected with BK virus (BKV), a human papovavirus. Because BKV has oncogenic properties, we have investigated whether it may be a cause of human cancer. Basic principles of tumor virology imply that BKV-induced tumors should contain BKV DNA sequences. Therefore, we assayed (by molecular hybridization) DNA from human tumors and malignant cell lines for BKV DNA, using BKV [(32)P]DNA as probe. The BKV [(32)P]DNA was labeled in vitro (nick translation) to specific activities of 1 to 2 x 10(8) cpm/mug. The BKV DNA used to prepare our probes had the properties expected of authentic BKV genomes, including density of superhelical DNA, sedimentation velocity in alkaline and neutral sucrose gradients, production of one fragment by endonuclease EcoRI cleavage and four fragments by endonuclease Hin II + III cleavage and reassociation properties. From these studies we conclude that our BKV probes hybridized well, and represented bona fide BKV DNA. Using three different BKV [(32)P]DNA probes, i.e., from three distinct plaque isolates, we have analyzed DNA from BKV-transformed cells, normal human tissues, and a large number of human tumors. All human DNAs (cell lines, normal tissues, tumors) hybridized 5% with BKV DNA. Hybridization analysis of BKV-transformed hamster cell DNA indicated 5-6 copies of at least 88% of the BKV genome per cell. No BKV DNA sequences were detected (above the normal 5% hybridization to all human DNAs) in the following normal human tissues: 10 kidney (BKV is usually isolated from urine), 3 spleen, 13 lung, 23 colon, 2 rectum, 1 ileum, and 1 skin. No BKV-specific DNA was found in 166 tumors, including 5 carcinomas (Ca) of stomach, 3 Ca small intestine, 26 Ca colon, 9 Ca rectum, 31 Ca lung, 9 adenocarcinomas and 5 oat cell carcinomas of lung, 17 melanomas, 5 Ca prostate, 4 Ca bladder, 6 Wilms tumors, 4 hypernephromas, 15 Ca kidney, 7 brain tumors, 5 Hodgkin lymphomas, 10 lymphomas (immunosuppressed patients have a high incidence of lymphomas), 2 reticulum cell sarcomas (spleen), and 3 skin tumors. We have also analyzed 7 human malignant cell lines (melanoma, lung, rhabdomyosarcoma, and glioblastomas), including several clones of a lung melanoma line; no BKV DNA sequences were detected. Because our probes could detect one copy of BKV DNA if only 10% of the cells were tumor cells, our results are very strong evidence that the tumors we analyzed did not have a BKV etiology. The tumors we tested represent about 50% of all cancers in the United States; there is no evidence that BKV is involved in the etiology of these types of tumors.
 ...
PMID:Analysis of human tumors and human malignant cell lines for BK virus-specific DNA sequences. 20 40

Several newly synthesized boron betaine analogs had antitumor activity in Ehrlich ascites, Walker 256 ascites carcinosarcoma, and Lewis lung screens and marginal activity in the B-16 melanotic melanoma screen. In vivo testing demonstrated that trimethylamine-cyanoborane inhibied Ehrlich ascites cell DNA and protein syntheses as well as gene modulation by chromatin protein phosphorylation and methylation. Trimethylamine-cyanoborane increased cyclic-AMP levels. In vitro testing showed that nuclear DNA polymerase, thymidylate synthetase, S-adenosylmethyltransferase, nonhistone chromatin methylation, deoxyribonuclease, ribonuclease, and cathepsin were inhibited by the boron analogs. These compounds did not demonstrate high antitumor activity at the doses employed, but blockage of methyl transfer from S-adenosylmethionine was established as a feasible method for controlling cell proliferation.
 ...
PMID:Boron betaine analogs: antitumor activity and effects on Ehrlich ascites tumor cell metabolism. 22 87

Sera of patients with various malignancies are known to contain DNA-binding proteins (DBP) which are not present in sera of normal individuals. In this paper sera of patients with malignant melanoma (MM) were examined as to whether characteristic DBP are present, too. DBP are isolated by DNA-affinity chromatography and represent 0.5-0.9% of all serum proteins. After separation of the DBP by SDS slab gel electrophoresis no typical DBP is detectable in sera of MM-patients. However, quantitative differences are found in sera of patients in the clinical stages I-III and/or tumor level 3-5: 1. All 9 sera of patients who had clinical signs of MM contain more DBP with molecular weight (mw) of 20,000-24,000 dalton than control sera. However, these DBP are only increased in 30% of the 22 sera from MM-patients who had clinical signs for 13-73 months after tumor excision. 2. All sera of the 10 MM-patients of whom sera were drawn twice after tumor excision at an interval of 7-46 months without clinical signs, showed a reduction of DBP with mw 30,000, 68,000, and 165,000.
 ...
PMID:DNA-binding proteins in the sera of patients with malignant melanoma. 22 3

In a model system, consistent transfection of chick embryo fibroblasts (CEF) by DNA from the XC cell line occurred, with recovery of infectious Rous sarcoma virus. The techniques were then applied in attempts to recover possible human tumour viruses. Even with various modifications of the XC technique, DNA from three human malignant melanoma cell lines failed to infect adult or foetal human fibroblasts, although melanoma DNA was taken up into nuclei of target cells. XC DNA did not transfect human foetal fibroblasts and melanoma DNA was ineffective in CEF. DNA from the Raji (Epstein-Barr virus non-producer) and QIMR-WIL (producer) lymphoblastoid cell lines did not transfect human cord blood lymphocytes or amnion cells. These broadly applicable techniques therefore failed to recover EB virus, the putative melanoma retrovirus, or other potential tumour virus.
 ...
PMID:Search for human tumour viruses by transfection: uptake of melanoma and Epstein-Barr virus DNA by human cells. 22 52

Twenty-one of 82 human cell lines examined for production of human chorionic gonadotropin and its subunits (HCG-alpha and HCG-beta) produced either one or both subunits at some phase in their growth. Of these, 14 produced an excess amount of free alpha subunit, and seven produced HCG-beta or complete HCG without evidence for free alpha subunit synthesis. Five of the HCG-producing cell lines also contained or secreted the beta subunit of human luteinizing hormone. CBT cells derived from a glioblastoma multiforme and JAR choriocarcinoma cells secreted significant amounts of the beta subunit of human luteinizing hormone, while three other cell lines (breast carcinoma MCF-7, HeLa S3, and melanoma A375) produced small amounts of the beta subunit of human luteinizing hormone but did not appear to secrete it. Two cell lines (the melanoma line A375 and the SV40-transformed line SV80) appeared to contain small amounts of human follicle-stimulating hormone. Sodium butyrate caused a 40-fold induction in the secretion of both HCG-alpha and HCG-beta by HeLa S3 cells, but the total amount of HCG-alpha secretion induced was 800-fold greater than that of HCG-beta. Induction was blocked by actinomycin D (1 microgram/ml) and cycloheximide (5 microgram/ml) but was not affected by 1-beta-D-arabinofuranosylcytosine at a concentration (5 microgram/ml) that blocked DNA synthesis 99%. These results indicate that a number of malignant human cell lines produce the subunits of both placental and pituitary gonadotropins and that there is frequently an excess secretion of the free alpha subunit common to these hormones.
 ...
PMID:Content of gonadotropins in cultured human malignant cells and effects of sodium butyrate treatment on gonadotropin secretion by HeLa cells. 22 11

Studies were undertaken to determine how a line of mutant Syrian hamster melanoma cells (HAB-2E) that displays unlimited growth potential when all of the thymine residues in nuclear DNA are replaced by bromouracil (BrUra) could avoid the deleterious effects of bromodeoxyuridine (BrdUrd) mutagenicity. It was found that BrdUrd could be mutagenic to these cells. However, there was a nonlinear relationship between mutagenicity and the amount of BrUra in the DNA of the HAB-2E cells. With these cells, mutagenicity apparently is determined by the concentration of BrdUrd to which the cells are exposed rather than the amount of BrUra in DNA. These results were obtained with both the induction of ouabain resistance and thioguanine resistance as markers for mutagenesis. The dependence of BrdUrd mutagenicity on BrdUrd concentration was also observed for the parental melanoma cells.
 ...
PMID:Bromodeoxyuridine mutagenesis in mammalian cells: mutagenesis is independent of the amount of bromouracil in DNA. 28 8

The effect of ultra-violet (U.V.)-irradiation on DNA replication was studied in a U.V.-resistant, human melanoma cell-line (MM96). Semi-conservative synthesis of DNA was decreased about five-fold by a U.V.-dose of 100 ergs/mm2. The size of DNA fragments synthesized in irradiated cells at short times after U.V. was smaller than those synthesized in unirradiated cells. Elongation of these fragments occurred with time, and 6 hours after irradiation cells synthesized DNA in fragments of the same size as obtained in unirradiated cells. In this post-replication repair process, elongation appeared to involve de novo synthesis and was not inhibited by theophylline.
 ...
PMID:DNA replication and repair in a human melanoma cell-line resistant to ultra-violet-radiation. 30 Jul 17

A material inhibiting growth of lymphocytes from different lymphoid organs and from different species was purified from calf spleen. A factor with a molecular weight of about 45,000 dal (estimated by gel chromatography) inhibited DNA synthesis and mitosis irreversibly in thymocytes and caused degenerative changes in the nucleus and the cytoplasm of the thymocytes as judged by electron microscopy. However, no decrease in cell number and no increase in dye uptake in a dye exclusion test were found. Growth inhibition was also demonstrated for human melanoma cells, but not for rat liver cells. The cytotoxicity and the lack of absolute lymphocyte specificity of the factor speak against its character as a lymphocyte chalone. A probably identical factor was purified from calf liver, but was not found in extracts of calf thymus.
 ...
PMID:Further studies on splenic material inhibiting the growth of lymphocytes in vitro. 31 11


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