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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A full-length complementary DNA (cDNA) for interstitial collagenase was isolated from an A2058 melanoma cDNA library using the pCD-X Okayama-Berg vector. The tumor interstitial collagenase cDNA was sequenced and compared to the published sequences for human fibroblast collagenase. The sequence for the tumor collagenase has two DNA base pairs which differ from the sequence of normal fibroblast collagenase. Restriction enzyme digestion of a specific DNA fragment produced by polymerase chain reaction amplification of genomic DNA from human placenta resolves a discrepancy in the previously reported DNA and amino acid sequences for the fibroblast collagenase. A high level of expression of interstitial collagenase message was found in human A2058 melanoma cells by Northern blot analysis, and this level was slightly increased by phorbol ester (phorbol myristate acetate) stimulation. Interstitial collagenase mRNA expression was significantly decreased by treatment with either transforming growth factor-beta 1 or retinoic acid in A2058 melanoma cells. A high level of the collagenase protein secreted into conditioned media was identified by Western blotting. As shown by gelatin zymogram analysis interstitial collagenase was one of at least two metalloproteinases secreted by this same cell line. Thus, human melanoma cells can directly produce interstitial collagenase without a requirement for host cell interaction.
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PMID:Cloning and characterization of human tumor cell interstitial collagenase. 216 56

The expression of mRNA for retinoic acid receptor beta (RAR-beta) was induced by all trans-retinoic acid in murine S91 melanoma cells. The induction of RAR-beta was dose-dependent, rapid and insensitive to cycloheximide. Both 13-cis-retinoic acid and 3,4-didehydro-all trans-retinoic acid also induced expression of RAR-beta but were only effective at concentrations 100-fold greater than all trans-retinoic acid. The expression of RAR-alpha and RAR-gamma was unaffected by retinoic acid.
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PMID:The biological activity of retinoids in melanoma cells. Induction of expression of retinoic acid receptor-beta by retinoic acid in S91 melanoma cells. 217 28

Treatment of B-16 melanoma cells in culture with d-alpha-tocopheryl succinate (vitamin E succinate) at concentrations of 11.3 and 15.1 microM inhibited growth and induced cell differentiation in culture. Vitamin E succinate treatment decreased the levels of c-myc and H-ras specific mRNAs in melanoma cells. Similar results were obtained by the vitamin retinoic acid and the nonvitamin agents R020-1724 (4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone), an inhibitor of cyclic nucleotide phosphodiesterase (0.72 mM), and sodium butyrate (1 mM), which induced differentiation and (or) inhibited growth of melanoma cells in culture. The extent of inhibition of c-myc mRNA was greater than that of H-ras mRNA. These results indicate that vitamin E succinate induced reduction of the levels of c-myc and H-ras mRNAs is related to growth inhibition of melanoma cells in culture.
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PMID:Decreased expressions of c-myc and H-ras oncogenes in vitamin E succinate induced morphologically differentiated murine B-16 melanoma cells in culture. 217 40

Retinoids inhibit the growth and enhance the differentiation of murine S91-C2 melanoma cells. Specific alterations in gene expression are a plausible mechanism for these effects. Since nuclear retinoic acid receptors (RAR) are likely mediators of retinoid-induced changes in gene expression, we used Northern blotting to analyze the expression of RAR alpha, RAR beta, and RAR gamma in S91-C2 cells. mRNA for both RAR alpha and RAR gamma was detected in these cells, but no RAR beta mRNA could be found. Treatment with 10(-7) and 10(-6) M beta-all-trans-retinoic acid (RA) for 24 h caused a 1.5- to 2-fold increase in RAR alpha and RAR gamma mRNA, whereas lower concentrations of RA were ineffective. RAR beta mRNA, which was undetectable in untreated cells, was detected after 24 h of treatment with a RA concentration as low as 10(-9) M, and its level increased with up to 10(-6) M RA. At the latter dose, RAR beta mRNA induction occurred by 4 h and increased progressively, reaching a plateau after 24 h of treatment. RAR beta mRNA induction at 4 h was not inhibited by cycloheximide at a concentration that suppressed protein synthesis by more than 90%. Several retinoids and related synthetic compounds, including 13-cis RA, TTNPB, Ch55, Am80, and the trifluoromethyl nonyloxyphenyl analog of RA, also induced RAR beta mRNA, whereas a 24-h treatment with 10(-6) M retinol, TTNP (a decarboxylated analog of TTNPB), or the phenyl analog of RA failed to induce RAR beta mRNA. With the exception of retinol and the trifluoromethyl nonyloxyphenyl analog of RA, the ability of the retinoids to induce RAR beta mRNA and their growth inhibitory effect were correlated. However, S91-C154, a RA-resistant mutant subclone derived from S91-C2 cells, showed mRNA levels of RAR alpha and RAR gamma and induction of RAR beta by RA similar to those detected in the sensitive S91-C2 cells. Like the S91 melanoma cells, two other mouse melanoma cell lines, K-1735P and B16-F1, constitutively expressed RAR alpha and RAR gamma mRNAs. The level of RAR beta mRNA was increased by RA only in B16-F1 cells, although the growth of both was inhibited by RA. These results demonstrate that RA can, directly and rapidly, induce the expression of mRNA for a high affinity nuclear receptor in some murine melanoma cells and that this induction is not sufficient to inhibit growth.
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PMID:Modulation by retinoids of mRNA levels for nuclear retinoic acid receptors in murine melanoma cells. 217 20

This investigation examined the effect of retinoic acid on tumor progression and immunological status of mice bearing the B16-F10 melanoma (previously selected for high lung-colonizing capacity). Tumor cells were implanted s.c. in syngeneic C57BL/6 mice, half of which were treated with beta-all trans retinoic acid (RA). Although RA failed to exhibit direct toxicity on this variant at the concentration used, the immunologic aberrations induced by the tumors were diminished by i.p. RA administration (at 45 micrograms twice/week for 3 weeks). In mice bearing B16-F10 tumors, tumor burdens were decreased from 2.9% of body weight to 1.6%. The mitogenic responses of splenic lymphocytes to concanavalin A (ConA) were increased in tumor-bearing mice following this RA treatment. The presence of these tumor cells decreased the absolute number of CD4- and CD8-positive splenic lymphocytes. Following RA treatment, the CD8-positive population was increased in tumor-bearing mice, while the CD4+ population was not significantly altered. Since previous studies indicated that plasma membrane fragments (or vesicles) could alter lymphocyte distributions and proliferative capacities, the in vitro shedding of membrane fragments from B16-F10 tumor cells was assayed and observed to be decreased after continuous treatment of cultures with 10(-6) M RA for 21 days. Membrane shedding from B16-F10 cells was inhibited by 48.5% following RA treatment. Based on these in vivo and in vitro results, we suggest that RA treatment may diminish tumor growth by decreasing tumor-induced immunosuppressive events.
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PMID:Effect of retinoic acid on tumor-mediated immunologic alterations in mice bearing a variant of the B16 melanoma. 224 92

Treatment of Cloudman S91 melanoma cells with retinoic acid (RA) inhibits MSH-induced tyrosinase activity and melanin formation [(1990) J. Invest. Dermatol. 94, 461-464]. We report here, however, that in spite of inhibiting MSH-induced pigmentation, RA treatment caused a marked increase in MSH binding capacity for both cell surface and internal MSH binding sites. The stimulation was dose- and time-dependent and reversible, with half-maximal effects seen at 2 microM RA. Stimulation of MSH binding was seen as early as 3 h after exposure of cells to RA. Cell surface and internal binding activity increased in concert. Scatchard analysis indicated that increased MSH binding resulted from a 3-4-fold increase in the number of sites with no significant difference in their affinity for MSH. It appears that in suppressing MSH-induced melanogenesis, RA elicited a compensatory up-regulation of the MSH receptor system.
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PMID:Stimulation of the receptor for melanocyte-stimulating hormone by retinoic acid. 226 2

The activity of liposome-associated retinoic acid was analyzed on in vitro cultured tumor cell lines and compared to the antiproliferative effects of free retinoic acid. It was found that liposome-associated retinoic acid is about 300 times more active than free retinoic acid in inhibiting in vitro cell growth of leukemic and melanoma cell lines. An increased activity of retinoic acid (10-20 times) was also obtained after premixing of this compound with empty liposomes, demonstrating that the retinoic acid efficiently interacts with liposomes which may facilitate solubility and cell uptake of retinoids.
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PMID:Liposome-associated retinoic acid. Increased in vitro antiproliferative effects on neoplastic cells. 229 18

Several studies suggest that beta-carotene reduces the risk of some cancers. Except for its function as an antioxidant, the effect of this vitamin on mammalian cells remains poorly defined. This study was performed to show whether beta-carotene treatment of murine B-16 melanoma cells in culture induces differentiation and alters the adenylate cyclase (AC) system. The AC system mediates the action of agents which regulate cell differentiation and transformation. Results showed that beta-carotene treatment for a period of 24 hours or more caused morphological differentiation without changing the level of melanin, and reduced basal and melanocyte-stimulated hormone (MSH)-, sodium fluoride (NaF)-, and forskolin-stimulated AC activity in vitro. Retinol, a metabolite of beta-carotene, inhibited growth without morphological differentiation and reduced basal and MSH- and NaF-stimulated AC activity. However, butylated hydroxyanisole, a lipid-soluble antioxidant, also reduced growth without morphological differentiation, but it failed to alter basal or MSH-stimulated AC activity. The present and previous studies show that the AC system represents a common site where some antitumor-promoting vitamins (beta-carotene, retinol, retinoic acid, and alpha-tocopheryl succinate) act.
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PMID:Beta-carotene induces morphological differentiation and decreases adenylate cyclase activity in melanoma cells in culture. 233 63

Improved serum-free media were developed for the anchorage-dependent growth of A549 human lung carcinoma and B16 mouse melanoma cell lines in vitro. Type 1 transforming growth factor beta (TGF-beta 1) inhibited the growth of A549 or B16 cells under serum-free conditions or in the presence of 10% serum by 15-33%. In contrast, in the presence of micrograms/ml concentrations of polyunsaturated fatty acids (PUFAs), picomolar concentrations of TGF-beta 1 irreversibly inhibited the serum-free growth of A549 or B16 cells by 90-100%. The PUFAs alone had little effect on cell growth. Cell growth inhibition by TGF-beta 1 was not potentiated by saturated fatty acids, monounsaturated fatty acids, or prostaglandins. Inhibition of A549 or B16 cell growth by TGF-beta 1 in the presence of PUFAs was almost completely reversed by the antioxidant vitamin E, suggesting a role for lipid peroxidation in this process. Inhibition of A549 or B16 cell growth by TGF-beta 1 in the presence of 5% fetal calf serum was also potentiated by PUFAs and partially reversed by antioxidants. The presence of retinoic acid was required for maximal PUFA-dependent growth inhibition of A549 or B16 cells by TGF-beta 1 under some, but not all, conditions. These results suggest that inhibition of carcinoma and melanoma cell growth by TGF-beta 1 is mediated, in large part, by PUFAs.
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PMID:Inhibition of carcinoma and melanoma cell growth by type 1 transforming growth factor beta is dependent on the presence of polyunsaturated fatty acids. 237 Dec 87

The effect of butyric acid (BA) and all trans-retinoic acid (RA) on murine melanoma cells was investigated in vitro and in vivo. The in vitro assays included 3H-IdUR incorporation, adhesion, migration and invasion experiments. Butyric acid decreased 3H-IdUR cellular incorporation within 24 h and increased adhesion as measured by trypsin release of 3H-IdUR labelled cells from either polycarbonate (p.c.) or Matrigel-coated p.c. membranes. Migration and invasion rates after 72 h were quantified by scanning electron microscopy (SEM). The invasion barrier consisted of Matrigel-coated p.c. membranes. Butyric acid significantly enhanced migration and invasion of B16a cells, while RA significantly decreased migration and invasion of B16a and K-1735 cells. Subcutaneous administration of either BA or RA pellets significantly decreased the number of lung nodules in the experimental metastatic assay. The experimental metastatic assay is defined as a tail vein inoculation protocol followed by subsequent lung evaluation.
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PMID:The effect of butyric acid and retinoic acid on invasion and experimental metastasis of murine melanoma cells. 239 Aug 13


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