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)

Xeroderma pigmentosum is a rare recessive disease with sun sensitivity, increased freckling and defective DNA repair. Xeroderma pigmentosum patients have more than a 1000-fold increased risk of developing skin cancer including basal cell carcinoma, squamous cell carcinoma and melanoma. We studied chemoprevention of new skin cancers with oral retinoids in xeroderma pigmentosum patients who had multiple skin cancers. Xeroderma pigmentosum patients were cleared of all pre-existing tumors surgically and then treated with high dose (2 mg/kg/day) oral isotretinoin (13-cis retinoic acid, Accutane) for two years and then for one year off treatment. Patients were examined at regular intervals for new tumor formation and for side effects. Five xeroderma pigmentosum patients had a total of 121 basal or squamous cell carcinomas in 2 years before treatment and only 25 tumors during 2 years of treatment. The tumor frequency increased 8.5-fold after the drug was discontinued (New Engl J Med 318: 1633-1637, 1988). Toxicity (cutaneous, triglyceride, liver-function or skeletal abnormalities) prompted subsequent use of a low dose protocol. Patients were treated initially with 0.5 mg/kg/day oral isotretinoin and the dose was increased sequentially to 1.0 or 1.5 mg/kg/day. We found that toxicity was less with the lower doses. The lowest effective, least toxic dose varied among the xeroderma pigmentosum patients.
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PMID:Chemoprevention of skin cancer in xeroderma pigmentosum. 129 59

The differentiation-inducing activity of doxorubicin on B16 melanoma cells grown in vitro was compared with that of other known differentiation inducers, such as theophylline, retinoic acid, and melanocyte-stimulating hormone (MSH). At drug concentrations resulting in cytostatic effects, doxorubicin and theophylline induced morphological changes (dendritic-like structures with a terminal melanin granule) with an enhancement of total melanin content and tyrosinase activity. Retinoic acid did not alter melanin content and cell morphology, although it affected cell growth. MSH enhanced total melanin content and tyrosinase activity, with no significant morphological changes. Flow cytometric analysis showed that MSH led to an accumulation of cells in G1 phase whereas doxorubicin induced an accumulation of cells in G2 + M. Studies on DNA content in doxorubicin-treated cells, selected on the basis of a morphologically differentiated pattern, showed a clustering of these cells in G2 + M, probably due to a cytokinesis block. Thus doxorubicin can induce cell differentiation comparable with other differentiation inducers.
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PMID:Comparative studies on the effects of doxorubicin and differentiation inducing agents on B16 melanoma cells. 132 7

Topical tretinoin improves mottling and hyperpigmented lesions of photodamaged skin. The basic mechanisms underlying these effects are not known. It is demonstrated that retinoids inhibit the growth and enhance the differentiation of melanoma cells in vitro, and stimulate the constitutive melanogenesis in melanoma cells in vitro. On the other hand, they inhibit hormonally or pharmacologically induced melanogenesis in these cells. Very few data are available concerning the effect of retinoic acid on normal human melanocytes, but there is some inhibition of growth as in melanoma cells. Retinoic acid appears to have little effect on the melanogenesis of normal human melanocytes grown in vitro using serum-free culture medium. Changes in the shape of these melanocytes suggest that retinoic acid acts on cytoskeleton proteins. Further studies, both in vitro and in vivo, are needed to clarify the effects of retinoic acid on melanocytes.
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PMID:Retinoic acid and pigment cells: a review of in-vitro and in-vivo studies. 132 62

It is well documented that activated macrophages, but not nonactivated ones, kill tumor cells in vitro without damaging normal cells. We, however, have previously shown that embryo-derived teratocarcinoma cells (F9, P19, PCC4) are efficiently killed by nonactivated macrophages as well as by activated ones. Whereas other tumor cells are killed extracellularly by macrophages, we found that F9 teratocarcinoma cells are phagocytosed alive by macrophages and subsequently killed intracellularly by a process dependent on intact lysosomal function. Neither the H-2 antigens nor the mRNAs for the alpha-chain and beta 2-microglobulin are detectable in embryo-derived teratocarcinoma cells. An obvious explanation for this unique killing is that the nonactivated macrophages recognize and kill these cells due to their lack of class I MHC antigen expression, assuming that class I MHC gene products on the target cells switch off the cytolytic machinery of nonactivated macrophages. Our present findings demonstrate that there is no correlation between H-2 antigen expression on tumor cells and their susceptibility to killing by macrophages. Retinoic acid-differentiated F9 cells and P19 cells expressing H-2 antigen after exposure to MAF (IFN-gamma) were sensitive to the killing by nonactivated macrophages. Hybrids that arose from fusion of P19 teratocarcinoma cells with embryonal normal fibroblasts (C57BL/6), which displayed the morphology of embryonal carcinoma stem cells and expressed H-2 antigens, were also sensitive to the killing by nonactivated macrophages. On the other hand, the H-2-negative testicular 402AX teratocarcinoma cells and K1735P melanoma cells were both resistant to the killing by nonactivated macrophages. We concluded that the unique killing of embryo-derived teratocarcinoma cells by nonactivated murine macrophages is not related to a lack of H-2 antigen expression.
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PMID:The unique killing of embryo-derived teratocarcinoma cells by nonactivated murine macrophages is not due to a lack of H-2 antigen expression. 162 57

In a group of four human tumor cell lines comprising one melanoma, one glioma, one teratocarcinoma and one neuroblastoma, the expression of the intercellular adhesion molecule-1 (ICAM-1) was found to be significantly increased following treatment with 10 microM of all-trans retinoic acid. In the melanoma and glioma cell lines HS 294T and HS 683, greater than 90% of the cells reacted with the anti-ICAM-1 monoclonal antibody (mAb) CL203.4 in the absence of treatment. Retinoic acid increased the cell surface expression of the molecule by 2-fold. In the teratocarcinoma and neuroblastoma cell lines, TERA-2 and SK-N-SH, the constitutive expression of ICAM-1 was weak, the percentage of cells stained above the background being less than 25%. Retinoic acid induced ICAM-1 expression in greater than 80% of the cells and increased the levels of expression by 2.5 to 3-fold. Immunoprecipitation studies in biosynthetically labeled cells as well as RNase protection analysis confirmed that retinoic acid treatment increased the amount of ICAM-1 at both the protein and mRNA level. The induction or stimulation occurred within 24 h, was maximal after 4 days and reversible.
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PMID:Regulation by retinoic acid of ICAM-1 expression on human tumor cell lines. 168 Mar 99

Retinoic acid, hexamethylene bisacetamide, sodium butyrate, and dimethylsulfoxide, four compounds which modulate phenotypic expression in a variety of neoplastic cell lines, all inhibited the induction of tyrosinase activity and melanogenesis by the combination of melanocyte-stimulating hormone and isobutylmethyxanthine in Cloudman S91 melanoma cells. Results were the same in assays of whole cells or in extracts made from them. Only retinoic acid, however, was effective at inhibiting the activation of dopachrome isomerase, another regulatory enzyme in melanogenesis. Despite inhibiting the effects of melanocyte-stimulating hormone (MSH) and isobutylmethylxanthine on tyrosinase activity, all of the agents tested increased the binding of MSH to intact cells. Ultrastructural analysis of treated cells following DOPA cytochemistry revealed that both retinoic acid and hexamethylene bisacetamide arrested melanosomal maturation at stage I-II. Retinoic acid resulted in a derangement of melanosomal structure. The specificity of these agents for preventing the induction of melanogenesis makes them powerful tools for the dissection of this complex cellular process.
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PMID:Inhibition of induced melanogenesis in Cloudman melanoma cells by four phenotypic modifiers. 170 21

The effect of retinoic acid on the induction of tyrosinase (EC 1:14.18.1) by imidazole was determined in cultured B16/C3 melanoma cells. Retinoic acid could block the induction of enzyme activity within 3 hours of addition to the culture medium at a physiological concentration (10nM). The blockade was similar to that of 3,3',5-L-triiodothyronine (T3) already reported. mRNA hybridizable to a tyrosinase DNA probe was induced by imidazole while retinoic acid and T3 blocked that increase. These observations suggest that retinoic acid can mimic the action of T3 in B16 melanoma cells in culture.
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PMID:Retinoic acid blockade of imidazole-induced tyrosinase expression in B16 melanoma cultures: similar effects of the active retinoid and triiodothyronine. 250 11

The effect of all-trans retinoic acid on metastatic B16 melanoma lung colonization and synthesis and properties of glycosaminoglycans was examined. Injection of tumour cells, pretreated with 10(-6) M-retinoic acid or grown to low density, into the tail vein of syngeneic C57 mice produced significantly fewer pulmonary tumours compared to subconfluent control cells. By cochromatography of glycosaminoglycans isolated from control ([14C]glucosamine-labelled) and 10(-6) M-retinoic acid-treated ([3H]glucosamine-labelled) cells on DEAE ion-exchange columns, differences in elution profiles were detected. Chondroitin sulphates isolated from retinoic acid-treated cells eluted at a lower salt concentration than those from control cells, while retinoic acid-treated cells synthesised heparan sulphates of a higher charge density than heparans from control cultures. These changes were apparent in both medium and trypsin-releasable fractions. Retinoic acid-treated cultures were seeded so that they were of a similar density to control cultures when harvested, as cell density was shown to affect glycosaminoglycan synthesis, the glycosaminoglycans from low-density cultures having similar properties to those isolated from retinoic acid-treated cultures. Retinoic acid treatment also reduced the overall synthesis of glycosaminoglycans while having little effect on the composition or distribution between medium, trypsin-releasable and cell-associated fractions. These observed changes in glycosaminoglycans may, in part, be responsible for retinoic acid-induced inhibition of lung colonization, and reduced adhesion to basement membrane components, which we have previously demonstrated.
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PMID:Retinoic acid-induced inhibition of lung colonization and changes in the synthesis and properties of glycosaminoglycans of metastatic B16 melanoma cells. 251 93

Retinoic acid inhibits the proliferation of B16 mouse melanoma cells. It also eliminates the ability of these cells to grow in soft agar. These biological actions of retinoic acid have been shown to be accompanied by an increase in the amount of cyclic AMP-dependent protein kinase and an induction of a new isozyme form (RII beta). In this report we demonstrated that retinoic acid-treated B16 melanoma cells had large increases in protein kinase C activity. This increased enzyme activity was accompanied by increases in both the number of phorbol dibutyrate binding sites and the amount of immunoreactive protein kinase C. Other treatments (melanocyte-stimulating hormone, serum deprivation) which inhibited the growth of these cells did not increase protein kinase C activity. When B16 melanoma cells were treated for a prolonged time (72 h) with phorbol dibutyrate, protein kinase C activity was barely detectable. Under these conditions, melanin production was inhibited and cell growth was accelerated. When retinoic acid was added together with phorbol dibutyrate, it prevented the growth stimulatory effect of the phorbol ester and increased protein kinase C activity. However, the absolute activity of the enzyme was still below that found in control cells and very much lower than in cells treated with retinoic acid alone. Taken together with our previous findings, we propose that the increase in protein kinase C might be part of a differentiation program induced by retinoic acid.
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PMID:Induction of protein kinase C in mouse melanoma cells by retinoic acid. 274 37

Retinoic acid (RA) and butyric acid (BA) were investigated for their effect on in vitro migration of highly metastatic murine B16a melanoma cells. These potential antitumor agents are known to alter the cytoskeleton. Our initial studies determined the 72 h cytostatic/cytotoxic concentrations of RA (1 X 10(-6) M 1 greater than 1 X 10(-5) M) and BA (1.5 mM)/ greater than 2.0 mM). Cytostasis by RA and BA was confirmed by autoradiography and radioisotope incorporation. For migration assays, cells were plated on 3 and 5 microns diameter pore polycarbonate membranes. Complete media was added containing RA or BA at time of plating. For BA pretreatment studies, BA was added to cells for 72 h prior to plating cells in fresh BA on the membranes. Top and bottom surface of the membranes were examined after 72 h of incubation by scanning electron microscopy. Although RA and BA induced cells on top of the membrane to change morphology as shown by phase, transmission and scanning electron microscopy, only BA enhanced the deformability of cells to allow for passage through the 3 micron diameter pores. Butyric acid enhanced migration through 3 micron diameter pore membrane by 511%. For 5 micron diameter pore membranes, 55.2% of the plated number of untreated early passage cells migrated to the bottom surface as compared to 57.3% for BA-treated cells and 14.9% for RA-treated cells. However, if cellular proliferation over the 72 h period was factored in, BA increased migration by 456% over the controls and pretreatment of cells with BA for 72 h prior to plating increased migration by 893%. Without considering proliferation, RA inhibited migration by 75% over controls. The decrease in migration observed in RA-treated cells was due to an inhibitory effect on cellular migration and a decrease in proliferation.
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PMID:The effects of retinoic acid and butyric acid on in vitro migration by murine B16a cells: a quantitative scanning electron microscopic study. 281 6


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