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

Removal of histones and other nuclear proteins greatly enhances the sensitivity of mammalian cells to DNA damage by ionizing radiation. We examined the possibility that the ease of dissociation of histones, or the association of other nuclear proteins with DNA, may differ between radioresistant and sensitive human tumor cells. Cells embedded in agarose were exposed to increasing salt concentrations prior to irradiation and examination using a microscopic gel electrophoresis method, the neutral comet assay. Induction of double-strand breaks increased by a factor of about 20 when cells of four human tumor cell lines, HT144 melanoma, HT29 adenocarcinoma, DU145 prostate carcinoma and U87 glioma, were exposed to 2 M NaCl prior to irradiation. Subtle differences in sensitivity to induction of double-strand breaks by radiation between cells of the four cell lines were also observed after extraction with 0.7-1.1 M NaCl; however, no correlation with radiosensitivity was apparent. While a significant number of histone and non-histone proteins are present after extraction with 1.2 M NaCl, these proteins apparently have only a minor influence on radiosensitivity. However, if they are allowed to remain with DNA during electrophoresis, about 15 times more strand breaks are required to produce a similar amount of DNA migration in both DU145 and HT144 cells. These results suggest that the association between proteins and DNA within the nucleus, as probed by extraction with sodium chloride, does not help to explain differences in intrinsic radiosensitivity among cells of these diverse tumor cell lines.
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PMID:Radiation-induced DNA double-strand breaks produced in histone-depleted tumor cell nuclei measured using the neutral comet assay. 772 28

Himastatin, a cyclohexadepsipeptide antibiotic, had in vivo antitumor activity against localized P388 leukemia and B16 melanoma but had no distal site antitumor activity. An in vitro Bacillus subtilis well-agar diffusion assay was employed to test the hypothesis that himastatin was enzymatically inactivated. The activity of himastatin against B. subtilis was inhibited when himastatin was mixed with mouse liver S9 fraction and microsomes. However, subsequent investigations demonstrated that the markedly decreased antibacterial activity was not enzymatic in nature but was related to the presence of certain fatty acid salts. Saturated fatty acid sodium salts with a carbon chain number of 8 or more reduced the antimicrobial activity of himastatin 50 to 100 times. If antibiotics such as ampicillin, bacitracin, chloramphenicol, and tunicamycin were used in place of himastatin, no meaningful reduction in antibacterial activity occurred. However, the antibacterial activity of the membrane-active peptide antibiotic polymyxin B, but not that of polymyxin E (colistin), was reduced in a manner similar to that of himastatin. Importantly, the activity of himastatin against HCT-116 colon adenocarcinoma cells in soft agar was markedly reduced in the presence of sodium palmitate as the reference fatty acid salt. The data indicate that himastatin may be trapped in micelles in vitro. It may be speculated that the lack of distal site antitumor activity resulted from similar complex formation between himastatin and lipids in vivo. The results also suggest that the cancer cytotoxic and antimicrobial effects of himastatin may result from interactions with the cell membrane.
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PMID:Inhibition of antibacterial activity of himastatin, a new antitumor antibiotic from Streptomyces hygroscopicus, by fatty acid sodium salts. 787 60

The Cesium salt of BSSB (Cs4B24H22S2), a common boron-neutron-capture-therapy (BNCT) agent, was injected into M2R mouse melanoma xenografts, and detected in vivo by 1H-observed, 10B-edited NMR spectroscopy. The technique of spin-echo difference spectroscopy, in which a proton spin-echo is detected following the alternating presence and absence of a 10B 180 degrees pulse was used. This method provides much higher sensitivity than direct 10B NMR detection, and should thus be suitable for in vivo detection in patients about to undergo BNCT treatment, where the infused agents are 95% isotopically enriched in 10B.
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PMID:In vivo detection of a boron-neutron-capture agent in melanoma by proton observed 1H-10B double resonance. 796 38

Microwave oven (mwo) is used to stimulate tissue fixation and to retrieve antigens damaged by fixation. Heavy metal salt solutions, water, and citric acid buffer (cab) have been suggested for this purpose. A serie of tumors treated with cab and phosphate-buffered saline (pbs) with mwo were studied immunohistochemically with 24 antibodies. Controls were treated in the same way, except for microwaving. The antibodies were directed against antigens of the following tumors: breast and prostate carcinoma, carcinoid, lymphoma and melanoma. The results showed that cab enhanced the immunoreactivity of the following antigens: estrogen receptors (AMAC), progesterone receptors (Novocastra), HMB45, vimentin, leukocyte common antigen, PCNA, p53, MIB-1 (Ki-67) and prostatic specific antigen. The antigens that did not improve their immunoreactivity, when compared with the control series were: factor VIII, keratin, Leu 22, L26, neuron-specific enolase, CEA, chromogranin, HBME-1, smooth muscle actin and EMA. Microwaving equally improved protein S100 and desmin either with cab or pbs. The only antigen that improved with pbs was actin. The results with B72.3 and NKI/C3 were poor and not reliable. In conclusion microwaving with cab enhances the immunoreactivity of the antibodies mentioned above leading to an increase in sensibility without loosing specificity.
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PMID:[Antigen retrieval by microwave oven with buffer of citric acid]. 799 28

A simple procedure has been developed for studying the transfer of DNA into cells using the process of receptor-mediated endocytosis. Poly-L-lysine 460 was covalently attached to the carbohydrate chains of avidin via periodate oxidation and NaBH4 reduction to give avidin-pLys460. Following purification through Sephacryl S-300, the conjugate was reacted with biotinylated transferrin. The resulting avidin-pLys460-[bio-transferrin] could be either fractionated by Superose 12 gel chromatography or used directly in experiments with DNA. Determination of the interaction between avidin-pLys460-]bio-transferrin] and DNA was carried out by nitro cellulose filter binding and agarose gel retardation assays. The conjugate was shown to bind DNA strongly, giving stable complexes soluble in 0.15-0.2 M salt solutions. Gene transfer using avidin-pLys460-[bio-transferrin] and the luciferase plasmid pRSVL was accomplished with Hela cells, alpha T3 pituitary cells and a human melanoma cell line used in the present study. Transfection was dependent on bio-transferrin and stimulated by the lysosomotropic agent chloroquine. The results are consistent with a receptor-mediated endocytosis mechanism of DNA delivery for Hela cells and a combination of receptor and adsorptive endocytosis for the alpha T3 pituitary and melanoma T-5 cell lines.
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PMID:Studies on the transfer of DNA into cells through use of avidin-polylysine conjugates complexed to biotinylated transferrin and DNA. 806 55

The selective phosphorylation of bisantrene (1) affords bis(phosphonoguanidinic acid) 6, a prodrug with enhanced aqueous solubility (as sodium salt 7) at physiological pH. Unlike 1, in a rat tail vein model, no precipitation was observed when bis(phosphonoguanidinic acid) 6 was injected. While in rats 6 hydrolyzed to monophosphonoguanidinic acid 9 with a half-life of ca. 12 min., complete hydrolysis to bisantrene required several hours. The corresponding monophosphonoguanidinic acid 9 was synthesized from bisantrene and also showed good solubility and antitumor activity. While the antitumor activities of 6 in mice were comparable to bisantrene against B-16 melanoma and P-388 and L-1210 leukemias, it was inactive in vitro vs several tumor cell types. Thus, its activity in vivo resulted from its ability to serve as a prodrug for bisantrene.
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PMID:N-phosphoryl derivatives of bisantrene. Antitumor prodrugs with enhanced solubility and reduced potential for toxicity. 834 Sep 13

To examine whether tumor-reactive monoclonal antibodies can be used to enhance photodestruction of human uveal melanoma cells, we conjugated photosensitizer chlorin e6 monoethylenediamine monoamide (CMA) with a melanoma-reactive monoclonal antibody IG12 and evaluated the effectiveness of this immunoconjugate (IC) in the destruction of OCM431 human uveal melanoma cells in vitro. RPMI1846 melanoma cells do not react with IC and were used as non-target cells. For control, target and non-target cells were treated with IC or light alone. The effects of IC and free CMA in the destruction of melanoma cells were compared. Cell survival was assessed by a colorimetric assay using tetrazolium salt MTT. Target (OCM431) cells preincubated with IC and irradiated with 5-40 J cm-2 showed light dose-dependent decrease in cell survival. At 40 J cm-2, OCM431 cells preincubated with IC showed only 6 +/- 1.4% viability. Under same treatment, non-target (RPMI1846) cells showed much less phototoxicity; cell survival was 54 +/- 2.1%. Treatment with free CMA and light at 40 J cm-2 showed similar phototoxicity to both target and non-target cells, with cell survival being 24.3 +/- 3.5% and 23.7 +/- 1.5%, respectively. These results show that our IC is effective in causing photodestruction of human uveal melanoma cells in vitro. The phototoxicity is selective and more potent than free CMA.
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PMID:Photoimmunotherapy of human uveal melanoma cells. 854 79

Both enantiomers of alpha-naphthyl 2-phenylpropanoate (PhPr(ONap)), N-acetylalaninate (AcAla(ONap)), N-methoxycarbonylalaninate (MocAla(ONap)), N-methoxycarbonylvalinate (MocVal(ONap)), N-acetylprolinate (AcPro(ONap)), and N-(trifluoroacetyl)prolinate (TfaPro(ONap)) were prepared and used with Fast Blue RR salt for activity staining of esterases separated by polyacrylamide gel electrophoresis. Comparison of the band thicknesses stained with each enantiomer indicates stereoselectivity of the major esterase in that band. Several esterases in normal rat liver, rat hepatoma-derived cells, and mouse B16 melanoma showed alteration or inversion of stereoselectivity by the substrate change from MocAla(ONap) to MocVal(ONap) or from AcPro(ONap) to TfaPro(ONap). The stereoselectivity of the major esterases for MocVal(ONap) was reversed between the murine liver and the B16 melanoma enzymes. The present staining with chiral naphthyl esters is very effective for surveying rapidly the stereoselectivity of animal tissue and cancer esterases.
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PMID:Direct evaluation of stereoselectivity of cancer esterases by polyacrylamide gel electrophoresis coupled with activity staining with chiral naphthyl esters. 859 76

Since benzodiazepines (BZs) have been shown to inhibit the growth of some cell lines, the effects of these drugs on human melanoma (M-6) cell growth were examined. Cell growth was measured by the tetrazolium salt (MTT) assay or the Hoechst 33258 DNA assay. Diazepam, a non-selective BZ agonist, and Ro5-4864, a peripheral-type agonist, inhibited M-6 cell proliferation by 36% and 55% with EC50s of 139 microM and 107 microM respectively, after four days of treatment in culture. The central-type agonists, clonazepam and flunitrazepam, were ineffective. The antiproliferative effect of diazepam was partially reversed by treatment with phorbol 12-myristate 13-acetate (PMA). Neither PK 11195, a peripheral-type BZ receptor antagonist, nor flumazenil a central-type antagonist, blocked the effect of diazepam, indicating that these BZ receptors are not involved. The effect of PMA suggests that the antiproliferative effect of the BZs may involve inhibition of a calcium/protein kinase C-related pathway in M-6 cells.
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PMID:Benzodiazepine-induced inhibition of human malignant melanoma (M-6) cell growth. 870 47

Bryostatin 1, a macrocyclic lactone, has undergone phase I trials as an anticancer agent. Because of the lipid solubility of this compound it must be delivered either in ethanol or in a PET formulation. During the trial, these vehicles caused a large number of treatment-related side effects. We have synthesized the triethanolamine salt of 26-succinylbryostatin 1 and find that this compound is approx. 100-fold more water soluble than bryostatin 1. Because of the potential for clinical use, we have evaluated the biologic activity of this compound. We find that in a concentration-dependent manner 26-succinylbryostatin 1 is capable of activating protein kinase C (PKC) in vitro and displacing [3H]PDBu from PKC. However, at all concentrations tested the activity was less than the parent compound bryostatin 1. Addition of bryostatin 1 but not 26-succinylbryostatin 1 to U937 leukemic cells in culture stimulated a drop in cytosolic PKC, secondary to translocation of PKC to the membrane. Although 26-succinylbryostatin 1 did not stimulate a drop in the cytosolic levels of PKC, addition to U937 cells activated transcription from an AP-1 enhancer construct and c-Jun protein phosphorylation in a similar fashion to bryostatin 1 and differentiation of U937 cells. Unlike bryostatin 1, 26-succinylbryostatin 1 was unable to cause aggregation of human platelets. Although injection of bryostatin-1 into mice carrying B16 melanoma inhibits tumor growth, there was no significant inhibition of melanoma growth when identical doses of 26-succinylbryostatin 1 were injected. Therefore, 26-succinylbryostatin 1 shares some but not all of the pharmacologic properities of bryostatin 1. This compound can activate protein phosphorylation without lowering cytosolic levels of PKC.
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PMID:Biological activity of 26-succinylbryostatin 1. 870 88


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