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)

Heparanase, an endo-beta-D-glucuronidase, has been associated with melanoma metastasis. Polyclonal antibodies directed against the murine N-terminal heparanase peptide detected a Mr approximately 97,000 protein on SDS-PAGE of mouse melanoma and human melanoma cell lysates. In an indirect immunocytochemical study, human A375-SM and mouse B 16-BL6 melanoma cells were stained with the anti-heparanase antibodies. Heparanase antigen was localized in the cytoplasm of permeabilized melanoma cells as well as at the cell surface of unpermeabilized cells. Immunohistochemical staining of frozen sections from syngeneic mouse lungs containing micrometastases of B16-BL6 melanoma demonstrated heparanase localized in metastatic melanoma cells. Similar studies using frozen sections of malignant melanomas resected from patients indicated that heparanase is localized in invading melanoma cells. Our studies suggest that (a) the N-terminus of the heparanase molecule in mouse and human is antigenically related; (b) heparanase antigens are localized at the cell surface and in the cytoplasm of metastatic human and mouse melanoma cells; and (c) heparanase antigens are enriched in invasive and metastatic murine and human melanomas in vivo.
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PMID:Immunochemical localization of heparanase in mouse and human melanomas. 235 86

Monoclonal antibody PAL-M1, which was selected to discriminate between nevocellular nevi and cutaneous melanomas, has not been characterized until now. Here we show that PAL-M1 is directed against the transferrin receptor (CD71). The molecules precipitated by PAL-M1 and by anti-transferrin receptor antibodies OKT9 and 5E9 from various human tumor cell lines (melanoma, hepatoma, and lymphoma) show identical characteristics on SDS-PAGE. PAL-M1 also specifically recognized mouse L cells expressing the human transferrin receptor gene. Competition experiments demonstrated that PAL-M1 and OKT9 recognize the same or a spatially close determinant. Immunohistochemical staining of a large series of melanocytic lesions indicates that the transferrin receptor can be considered as a progression antigen in this type of lesion.
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PMID:Monoclonal antibody PAL-M1 recognizes the transferrin receptor and is a progression marker in melanocytic lesions. 236 2

Murine monoclonal antibody (MAb) LS109 was one of a series of MAbs produced by hyperimmunization of mice with detergent extracts of pooled melanoma cell lines and metastatic melanoma patient tumors. ELISA screening of extracts of individual cultured melanoma cell lines and single patient tumors with MAb LS109 gave an interesting pattern of reactivity. The antibody was strongly positive with some of these extracts, yet negative or weakly positive with others. In addition, there was strong reactivity with a restricted set of normal necropsy tissues and certain non-melanoma tumor extracts. Taken together, our data suggest that MAb LS109 recognizes a normal differentiation antigen which is perhaps aberrantly expressed or over-produced during certain stages of melanoma tumor progression. The antigen recognized by LS109 is a heterodimeric surface glycoprotein molecule, consisting of an 89-kDa "heavy" chain linked by disulfide bonds to an 83-kDa "light" chain. Under non-reducing SDS-PAGE conditions, the intact dimer migrates with an Mr of approximately 140kDa. The 89-kDa component appears to be heavily N-glycosylated whereas the 38-kDa component has little, if any, covalently attached carbohydrate. Our data show the biosynthesis, glycosylation and turnover of the LS109 antigen, as well as evidence of its surface localization. In addition, evidence is presented that the LS109 antigen is identical to the 4F2 cell activation/proliferation molecule previously described on a variety of normal and neoplastic cells.
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PMID:Isolation and characterization of a heterodimeric surface antigen on human melanoma cells and evidence that it is the 4F2 cell activation/proliferation molecule. 240 79

The relationship of antigenic heterogeneity to the epitope recognized by an antibody was examined with monoclonal antibodies to human melanoma-associated antigens. Expression of the human melanoma-associated antigens, 250-Kd glycoprotein/proteoglycan and p97, was examined quantitatively by flow cytometry on fresh cell suspensions of human melanoma. Percent positive cells and mean fluorescence intensity were consistently higher with antibody 9.2.27 to the 250-Kd glycoprotein/proteoglycan than with antibody to p97. In addition, assessment of percent positive cells in multiple skin lesions biopsied from individual patients indicated that in 26 of 30 lesions, greater than 90% of the cells stained positively with 9.2.27. This relative lack of antigenic heterogeneity with antibody 9.2.27 contrasted with previous reports which showed considerable antigenic heterogeneity with other antibodies to the 250-Kd glycoprotein/proteoglycan. The explanation for this distinction was sought by quantitative flow cytometric and sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques. Comparison by flow cytometry and immunoperoxidase of three antibodies, which recognized distinct epitopes of the 250-Kd glycoprotein/proteoglycan, indicated that 9.2.27 reacted more intensely with cultured cells and tissue sections than other antibodies to the same antigen. Examination by SDS-PAGE indicated that 9.2.27 could immunoprecipitate a larger proportion of 250-Kd glycoprotein molecules than other antibodies. In addition, immunodepletion experiments in gels indicated that the 9.2.27 determinant was present on a higher proportion of 250-Kd glycoprotein molecules than PG-2 antibody to a separate determinant. It is likely that 9.2.27 antibody displays less antigenic heterogeneity because its epitope is represented on a higher proportion of the antigen molecules. Thus, not only the nature of the antigen but also the epitope recognized by an antibody influences the degree of antigenic heterogeneity.
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PMID:Human melanoma-associated antigens: analysis of antigenic heterogeneity by molecular, serologic and flow-cytometric approaches. 242 45

The role of protein phosphorylation in MSH-induced melanogenesis was investigated with an in vivo phosphorylation assay using intact cultured Cloudman S91 mouse melanoma cells preincubated with [32P]orthophosphate. Exposure of the cells to alpha-MSH increased the extent of labelling of two protein bands on SDS gel electrophoresis with estimated molecular weights of 43 and 34 kDa, respectively. The 32P incorporation was concentration-dependent and reached a maximal value at 10(-8) M alpha-MSH for the 43 kDa band (156% of controls) and at 10(-5) M alpha-MSH for the 34 kDa band (250% of controls). The corresponding ED50s were 5 X 10(-10) M (43 kDa) and 3 X 10(-8) M (34 kDa). The 32P incorporation into the 34 kDa band reached a maximum after a 5 min exposure to alpha-MSH whereas 43 kDa phosphorylation was maximal after a 30-60 min incubation with hormone. The effect was completely reversible after removal of the hormone and specific for melanotropic peptides. Dibutyryl cAMP (10(-3) M) and forskolin (10(-4) M) together with isobutylmethylxanthine (10(-4) M) mimicked the effect of alpha-MSH, pointing to an involvement of adenylate cyclase activation in the phosphorylation of both the 34 kDa and the 43 kDa protein. Preliminary observations showed that the 34 kDa protein is membrane-bound whereas the 43 kDa protein is of mitochondrial or melanosomal origin.
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PMID:alpha-MSH-induced changes in protein phosphorylation of Cloudman S91 mouse melanoma cells. 243 92

Two monoclonal antibodies (MAbs), 140.240 and 96.5, generated independently in different laboratories, have been shown to detect the target structures of 87,000 (gp87) and 97,000 (p97) glycoproteins, respectively, both strongly expressed by melanoma cells and fetal small intestine. To determine whether MAb 140.240 and MAb 696.5 recognized a same target structure, they were tested in immunoprecipitation/SDS-PAGE using NP-40 lysates of melanoma cells labelled with [35S]methionine for 18 hr. Both antibodies precipitated a single band with Mr = 87,000. Reciprocal immunodepletion studies showed that neither of the two antibodies detected the 87,000 band in the lysate immuno depleted by either antibody, suggesting that these two antibodies recognize the same or extremely similar molecules. Two-dimensional tryptic peptide mapping analysis showed that the two identified molecules shared the same finger-printing pattern. A 40,000 fragment of the 87,000 molecule produced by protease digestion was precipitated by MAb 96.5 but not MAb 140.240, indicating that the epitopes recognized by the two antibodies are localized at discrete sites on the molecule. Serological studies on these two antibodies revealed slightly different binding patterns in the MAb 140.240 exhibited a more melanoma-restricted specificity, while MAb 96.5 had a specificity to melanoma and to some other cell types. The observed difference in epitope specificity may be important in the clinical applications of these antibodies.
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PMID:Difference in cell binding patterns of two monoclonal antibodies recognizing distinct epitopes on a human melanoma-associated oncofetal antigen. 244 Dec 44

We established an enzyme labelled immunoassay (EIA) for the determination of alpha 2-macroglobulin (alpha 2M). The sensitivity was high enough to measure trace amount of alpha 2M secreted into the medium of cell culture. The assay range in medium was from 2 to 140 ng/ml and the within-assay coefficients of variation (CV) were 10.1% and 6.7% at 31.2 ng/ml and 62.5 ng/ml, respectively. Between-day CV ranged from 9.3% to 15.9%. Using this method, alpha 2M was detected in the medium of a cultured human melanoma cell line. In addition, the immunoreactive alpha 2M in the medium was identified with serum alpha 2M by the method of SDS-PAGE and Western blotting. Our results indicate that the EIA method could be a useful tool for the determination of alpha 2M in cell cultured medium.
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PMID:Measurement of small quantities of alpha 2-macroglobulin in cell cultures by enzyme labelled immunoassay. 248 13

Because glycosylation-dependent melanization inhibition induced in cultured B-16 melanoma cells by glucosamine is reversible, producing synchronized initiation of melanogenesis after its removal, we have analyzed the possible dynamics of initial melanogenesis through their interruption by glutathione. The addition of glutathione at 0.2% concentration to the theophylline-stimulated recovery process completely interrupts the initiation of melanization for at least 72 h. At the electron microscopic level, theophylline-treated cells have many vacuolar melanosomes with distinct pigmentation which contain some vesicles (64% of total premelanosomes) or amorphous, filamentous, or granular materials within the interior which are suggestive of pheomelanotic melanosomes. The addition of glutathione induces a complete absence of melanization in the premelanosomes, within which a filamentous interior with periodicity is generally re-formed with almost complete disappearance of internal vesicles, providing dramatic changes to the size and shape characteristic of eumelanotic melanosome. Electron microscopic dopa reaction of glutathione-treated cells shows a predominant localization of tyrosinase activity in the Golgi-associated endoplasmic reticulum-lysosome and coated vesicles, but not in premelanosomes, in contrast to their dispersed distribution in all melanogenic organelles in the theophylline-treated control, suggesting a lack of tyrosinase translocation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of tyrosinase in the large granule fraction shows that in analogy with electron microscopic observations, glutathione blocks the reappearance of membrane-bound T3 tyrosinase which occurs in the theophylline-treated control during the recovery process, whereas the dynamics of T1 tyrosinase is almost the same as that of the control. These findings suggest that glutathione provides a new situation of interrupted melanogenesis in which melanization cannot proceed despite complete formation of melanosome matrix structure and a lack of inhibition of cellular metabolisms including protein glycosylation.
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PMID:Analysis of initial melanogenesis including tyrosinase transfer and melanosome differentiation through interrupted melanization by glutathione. 250 95

A preparation procedure is presented for the determination of tyrosinase-catalysed stereo-specific dopa oxidase activity in serum. Purification is obtained by separation on a Phenyl-Sepharose hydrophobic interaction column, followed by Con-A-Sepharose chromatography. Five out of seven sera from patients with widespread melanoma metastases were found to contain detectable quantities of tyrosinase. There was no tyrosinase activity in seven sera from patients with other malignancies, nor in six other control sera from individuals without malignancies. One serum which showed high tyrosinase activity was processed as above and studied by SDS-PAGE. A dopa-reactive band with an apparent MW of 66 kD was present in the gel, i.e. at the same place as that of the soluble tyrosinase of cultured human malignant melanoma cells. The protein was found to have the same pI at isoelectric focusing, and eluted in the same way from the preparation columns used, as did soluble tyrosinase.
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PMID:Tyrosinase activity in serum from patients with malignant melanoma. 256 28

Tyrosinase was isolated from cultured melanoma cells using a procedure involving solubilization of the enzyme by means of Triton X-100, followed by different types of chromatography and tryptic digestion to make the enzyme soluble even in the absence of detergent. Starting with a membranous material containing 72 mg protein, 0.21 mg tyrosinase was obtained. The recovery of tyrosinase was 36% of the quantity found in the membranous starting material. In order to acquire a completely purified enzyme preparation suitable for amino acid sequence analysis, SDS-PAGE followed by blotting onto a polyvinylidene difluoride membrane was performed as a final step. The apparent molecular weight was found to be 66,000. Determination of the amino acids of the aminoterminal portion by automated Edman degradation showed the following sequence: His-Phe-Pro-Arg-Ala-X-Val-Ser-Ser-Lys-Asn-Leu-Met-Glu-Lys-Glu-X-X-Pro-Pr o-The enzyme purified has an amino acid sequence identical with that of human tyrosinase deduced from c-DNA by Kwon et al. Striking similarities between our amino acid sequence and that predicted by Yamamoto et al. from mouse tyrosinase c-DNA were also observed.
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PMID:Isolation of human tyrosinase from cultured melanoma cells. 256 29


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