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)

A hypothalamic hormone--melanostatin H-L-Pro-L-Leu-NH2- and its 9 analogs were synthesized and their antitumor properties studied. Melanostatin caused a 52-72% inhibition of tumor growth (p less than 0.05) in mice bearing adenocarcinoma of the mammary gland Ca-755, cervical carcinoma CC-5 and melanoma B-16. Non-cytotoxic analogs containing D-leucine or L-lysine showed low activity. Among analogs containing sarcolysine stereomers, chlorphenacyl or chlorambucil, derivatives with L-sarcolysin exerted a high antitumor effect on Ca-755, CC-5, Lewis lung carcinoma, lymphoid leukemia L-1210, sarcoma-37, melanoma B-16 and S-91 (80-99% inhibition of tumor growth, p less than 0.05). L-sarcolysin alone had a higher effect on S-91 only (p less than 0.05). Antitumor effect of melanostatin is due to its amino acid sequences. Melanostatin analogs modified by L-phenylalanine retain their antitumor properties.
 ...
PMID:[Use of the peptide hormone melanostatin and its analogs for the synthesis of new antitumor compounds]. 289 89

The toxicity and selectivity of 3,4-dihydroxybenzylamine (DHBA), an experimental antimelanoma agent that cannot enter the melanin pathway, broadly paralleled that of L-dopa in a panel of human melanoma cell lines sensitive or resistant to the latter drug. A human retinoblastoma cell line was found to be sensitive to both compounds. The toxicity and selectivity of both catechols were associated with inhibition of DNA synthesis; DHBA was more potent yet allowed a much greater degree of recovery compared with an equitoxic level of dopa. Dopa and DHBA had similar, dose-dependent effects on the cell cycle, arresting cells in S phase at low doses and in G1 at high doses. Replication of the DNA virus adenovirus was found to be inhibited by both agents. There was no difference between sensitive and resistant cell lines in the manganese or copper/zinc forms of superoxide dismutase, or in iron content and iron-binding capacity. Catechol toxicity was inhibited by the hydrogen peroxide scavenging agents pyruvate and methaemoglobin. Sensitivity to catechols did not correlate with melanin or tyrosinase content, rate of incorporation of tyrosine or dopa, intracellular levels of phenylalanine or tyrosine, or binding of a new monoclonal antibody directed against a melanosomal protein. These results indicate that DHBA and dopa exhibit selective toxicity for neural crest tumor cells independently of the melanisation pathway and of the superoxide scavenging system.
 ...
PMID:Melanin synthesis and the action of L-dopa and 3,4-dihydroxybenzylamine in human melanoma cells. 290 84

The effect of dietary tyrosine and phenylalanine restriction on splenic natural killer (NK) cell activity was studied in tumor-free B6D2F1 and NIH nude mice and in B16 bladder-6 (BL6) melanoma-bearing B6D2F1 mice. This dietary restriction was found to suppress the naturally elevated NK-cell activity of nude mice and to induce a specific lymphocytopenia in B6D2F1 mice fed the restricted diet for a prolonged period. Baseline NK-cell activity was significantly lower in tumor-free B6D2F1 mice fed a diet restricted in tyrosine and phenylalanine (restricted diet) than in tumor-free mice fed a basal diet. Similar kinetics of activation after a single i.p. injection of 100 micrograms of polyinosinic:polycytidylic acid (poly I:C) were observed in mice fed both diets. NK-cell activity was not significantly augmented after i.v. inoculation of BL6 melanoma, irrespective of the diet fed; however, it was enhanced in tumor-bearing mice after poly I:C injection. This augmentation was similar to that observed in tumor-free mice. Spleen cells from mice fed either diet were responsive to stimulation of NK-cell activity after in vitro incubation with interleukin-2. These results indicate that dietary restriction of tyrosine and phenylalanine, a potentially useful therapeutic adjunct known to lower NK-cell activity, does not significantly interfere with poly I:C or interleukin-2 induction of NK cells. Our results also demonstrate that, while this dietary restriction causes lymphocytopenia, no effect of the diet could be found on total serum IgG or circulating immune complex levels.
 ...
PMID:Response of natural killer cells from dietary tyrosine- and phenylalanine-restricted mice to biological response modifiers. 296 70

The fluorescein-labeled melanotropin [N alpha-chlorotriazinylaminofluorescein-Ser1,Nle4,D-Phe 7]-alpha-MSH, was prepared by solid-phase techniques of peptide synthesis. The biological actions of this analogue were determined in several melanocyte bioassays and were compared with the parent peptide [Nle4,D-Phe7]-alpha-MSH and the native hormone alpha-MSH. The fluorescein compound was a superpotent agonist with approximately 10 times more activity than alpha-MSH in both the frog and the lizard skin bioassays. Murine S91 melanoma cells assayed in vitro (tyrosinase bioassay) were as responsive to the fluorescein analogue as to alpha-MSH. The analogue exhibited ultraprolonged biological activity and the biological activities were unaffected by treatment of the analogue with alpha-chymotrypsin. The fluorescein-labeled melanotropin should prove useful for melanotropin receptor characterization.
 ...
PMID:Synthesis and biological evaluation of the superagonist [N alpha-chlorotriazinylaminofluorescein-Ser1,Nle4,D-Phe7]-al pha-MSH. 298 82

Electron spin resonance (ESR) and high pressure liquid chromatography (HPLC) were utilized to characterize the physical and biochemical characteristics of melanin in choroidal melanoma. ESR free radical signals indicative of eumelanin could be elicited from formalin-fixed paraffin-embedded tissues. Zinc ions (50 mM) increased the number of melanin-free radicals resulting in greater ESR sensitivity. Pyrole 2,3,6 tricarboxylic acid (PTCA) and amino hydroxy phenylalanine (AHP) were identified by HPLC after permanganate oxidation and hydroiodic acid hydrolysis, respectively, of a choroidal melanoma obtained at enucleation. The results indicate eumelanin is the primary melanin type in posterior choroidal melanomas. The feasibility of these techniques in the detection of metastatic disease from ocular melanomas is discussed.
 ...
PMID:Electron spin resonance and high pressure liquid chromatographic analysis of melanin in posterior choroidal melanomas. 299 59

Melanotropins induce melanogenesis in mouse Cloudman S91 melanoma cells by stimulating the activity of tyrosinase. In monolayer culture, alpha-melanocyte-stimulating hormone and the superpotent analogue 4-norleucine, 7-D-phenylalanine-alpha-melanocyte, which had prolonged effects on tyrosinase activity, did not inhibit the proliferation of melanoma cells even at concentrations that elicited maximal tyrosinase stimulation. In soft agar the melanotropins stimulated the formation of melanized colonies and increased the cloning and proliferative potentials of melanoma cells. Both melanotropins increased the number of small (42-104 microns in diameter) colonies at initial plating densities ranging from 625 to 7,500 cells/dish. The number of larger (greater than 104 microns in diameter) colonies was also increased except at densities 5,000 cells or more/dish, wherein the proliferative capacity was inhibited; yet the cloning efficiency was still increased. Therefore, in bilayer soft agar cultures, melanotropins stimulate the growth of the clonogenic S91 melanoma cell population under conditions that allow for optimal expression of the cloning and proliferative potentials of these cells.
 ...
PMID:Actions of melanotropins on mouse melanoma cell growth in vitro. 300 49

Ninety-three patients with stage I primary cutaneous malignant melanoma of the lower limb were treated by wide local excision and hyperthermic isolated regional perfusion with melphalan (L-phenylalanine dihydrochloride) in a prospective non-randomized study between 1976 and 1982. Eighteen patients (19.4%) developed recurrent melanoma. Nine had recurrent regional disease, one with in transit metastases and eight with positive regional nodes. Nine patients developed distant metastases. No patient had locally recurrent disease. This series confirmed the close correlation between tumour microstaging, melanoma recurrence and survival. Seventy-nine per cent of patients were disease-free at 5 years. Males had deeper lesions (mean 4.56 mm) and increased recurrence (33%) than females (mean 3.36 mm and 13%). Superficial spreading melanoma had the most favourable prognosis of the three histological types. Overall survival was 83% (female 86%; males 64%) at 5 years. Significant morbidity occurred in two patients with deep vein thrombosis. Adjuvant therapy using hyperthermic regional perfusion provides improved local and intransit control of limb melanoma.
 ...
PMID:Prophylactic hyperthermic limb perfusion in stage I melanoma. 304 34

Melphalan (L-phenylalanine mustard) is a bifunctional alkylating agent that is commonly administered orally to treat a wide variety of malignancies, including cancers of the breast and ovary, as well as multiple myeloma. Although commercially available in Europe and Canada, intravenous (IV) melphalan remains investigational in the United States. The role of IV melphalan in cancer chemotherapy is not well defined, despite its manageable toxicity and higher and more predictable blood levels following IV administration compared with oral administration. In addition, unlike oral melphalan, an extensive phase I evaluation of IV melphalan has not been undertaken. At lower doses (eg, 30 to 70 mg/m2), both as a single agent and in combination, the activity of IV melphalan has been evaluated in only a limited number of diseases. However, striking activity has been observed in previously untreated patients with rhabdomyosarcoma, a disease not generally considered responsive to alkylating agents. When administered at high doses (greater than 140 mg/m2) requiring bone marrow reinfusion, melphalan effects a high response rate (but no improvement in survival) in a variety of nonhematologic tumor types, including resistant tumors such as melanoma and colon carcinoma. In contrast, in poor-prognosis patients with non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma, or neuroblastoma, high-dose melphalan-containing regimens have yielded both high response rates and improved survival, despite considerable toxicity. Additional clinical trials will be necessary to define the spectrum of activity of lower doses of IV melphalan and to define subgroups of patients most likely to benefit from high-dose melphalan.
 ...
PMID:The systemic administration of intravenous melphalan. 305 5

A new class of compounds, termed "dopa phosphates," is described. The compounds contain phosphate ester linkages at positions 3 and/or 4 of the phenylalanine ring. Dopa phosphates are highly soluble compounds which are stable over a wide range of pH values and are not hydrolyzed by boiling in concentrated acid. Synthetic yields of greater than 90% can be obtained using dopa as starting material. Exposure to alkaline phosphatase results in hydrolysis of the phosphate moieties and production of dopa. Dopa phosphates do not inhibit dopa oxidase (tyrosinase, EC 1.14.18.1) activity. Dopa oxidase does not catalyze the conversion of dopa phosphates into melanin unless the dopa phosphates are first treated with alkaline phosphatase. Dopa phosphates, when compared to L-dopa, are stable in the presence of O2 and are not oxidized by serum proteins. In the presence of cultured melanoma cells, dopa phosphates are readily converted into melanin, indicating that the cells are able to produce dopa from dopa phosphates. At high concentrations, dopa phosphates are cytotoxic toward melanoma cells in culture. The cytotoxicity is enhanced at least 3-fold by pretreatment of cells with melanotropin and is prevented by phenylthiourea, an inhibitor of dopa oxidase activity. These results, combined with studies on the uptake of radioactive forms of dopa phosphates (32P and 14C), indicate that phosphorylated isomers of dopa are efficiently taken up by Cloudman melanoma cells and are readily converted by the cells into a melanin precursor, presumably L-dopa.
 ...
PMID:Increase in melanin formation and promotion of cytotoxicity in cultured melanoma cells caused by phosphorylated isomers of L-dopa. 307 62

Ac-[Nle4, D-Phe7]-alpha-MSH4-9-NH2 and Ac-[Nle4]-alpha-MSH4-9-NH2, fragment analogs of the tridecapeptide, alpha-melanocyte stimulating hormone (alpha-MSH, alpha-melanotropin), were synthesized. The potency and prolonged activity of the analogs were compared to alpha-MSH in several melanotropin bioassays. The D-Phe-containing hexapeptide was 10 times more active than alpha-MSH in stimulating melanoma tyrosinase activity. This analog was also 10-fold more potent than alpha-MSH in the lizard skin bioassay and about 10-fold less active in the frog skin bioassay. The melanotropic activity of Ac-[Nle4, D-Phe7]-alpha-MSH4-9-NH2 was considerably prolonged compared to alpha-MSH in each of the bioassays. These results demonstrate that the structural requirements for superpotency and prolonged activity of [Nle4, D-Phe7]-substituted analogs reside within this hexapeptide sequence.
 ...
PMID:Potent and prolonged melanotropic activities of the alpha-MSH fragment analog, Ac-[Nle4,D-Phe7]-alpha-MSH4-9-NH2. 308 18


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