UMLS:C0025202 - FACTA Search

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

Monoclonal antibodies (Mab) directed against distinct epitopes of the human 240 kD melanoma-associated antigen have been evaluated for their capacity to localize in human melanoma grafted into nude mice. A favorable tumor to normal tissue ratio of 13 was obtained with intact 131I-labeled MAb Me1-14. This ratio was further increased to 43 and 23 by the use of F(ab')2 and Fab fragments, respectively. The specificity of tumor localization was demonstrated by the simultaneous injection of F(ab')2 fragments from MAb Me1-14 and anti-CEA MAb 35, each labeled with a different iodine isotope, into nude mice grafted with a melanoma and colon carcinoma. The fragments from both MAb localized with perfect selectivity in their relevant tumor as shown by differential whole body scanning and by direct measurement of the two isotopes in tumors and normal tissues. These in vivo experimental results suggest that the F(ab')2 fragment from MAb Me1-14 is suitable for melanoma detection by immunoscintigraphy in patients.
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PMID:Selective tumor localization of radiolabeled anti-human melanoma monoclonal antibody fragment demonstrated in the nude mouse model. 242 21

NKI/C-3 and NKI/black-13 are monoclonal antibodies recognizing different epitopes on a melanoma-associated antigen that is preserved after fixation in formalin and embedding in paraffin in virtually all melanoma tissues. The antigen, a predominantly cytoplasmic vesicle membrane-bound heterogeneous glycoprotein of 25-110 X 10(3) daltons, was shown to be a single 25 X 10(3) dalton polypeptide when incorporation of N-linked carbohydrates was inhibited by tunicamycin. The antigen was measured in a double determinant enzyme immunoassay (DDEIA) using NKI/C-3 as catcher antibody. Results from in vitro experiments indicated that the antigen is actively shed from living cells. In sera from melanoma patients with a small tumor burden, the antigen concentrations were in the range of those of controls (0-22 U/ml). Significantly increased values (33-600 U/ml) were found in sera from patients with a moderate or large tumor burden. The antigen concentrations in sera from patients with multiple metastases of other tumors were within the range of controls. Several sera from patients with multiple metastases of colon, pancreatic, and stomach carcinoma, however, contained increased antigen concentrations (45-80 U/ml). These results correspond with the reactions of NKI/C-3 in tissue sections of some malignancies other than melanoma. During the follow-up of melanoma patients the concentrations of circulating antigen correlated with tumor progression. The predictive value of the NKI/C-3 assay was no better than determination of serum lactate dehydrogenase, alkaline phosphatase or gamma glutamyl transferase activity.
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PMID:Circulating melanoma-associated antigen detected by monoclonal antibody NKI/C-3. 243 Jul 6

The effect of leukocyte (IFN-alpha), fibroblast (IFN-beta), and immune (IFN-gamma) interferon and/or mezerein on the expression of HLA antigens and melanoma-associated antigens by the melanoma cell line MeWo and its metastatic variant MeM 50-10 was investigated, since this information may contribute to our understanding of the molecular mechanism(s) underlying the metastatic process and of the role of cell differentiation and growth suppression in the antigenic changes induced by interferon (IFN). The three types of IFN had no effect on the expression of high-molecular-weight melanoma-associated antigen, but enhanced that of HLA Class 1 antigens and of intercellular adhesion molecule 1 on MeWo and MeM 50-10 cells. The enhancing effect of IFN-gamma was more marked than that of IFN-alpha and IFN-beta. Furthermore IFN-gamma enhanced the expression of intercellular adhesion molecule 1 by MeM 50-10 cells more than by MeWo cells. IFN-beta was shown for the first time to induce HLA Class II antigens; the effect of IFN-beta, like that of IFN-gamma, is differential on the two cell lines and on the gene products of the HLA-D region. Like IFN-gamma, IFN-beta induced only HLA-DR antigens on MeM 50-10 cells. The results of Northern blot analysis with HLA-DR beta, -DQ beta, and -DP beta probes suggest that the differential modulation of the gene products of the HLA-D region by IFN-beta and IFN-gamma reflects transcriptional and posttranscriptional events. The differential susceptibility to modulation by IFN-beta and IFN-gamma of HLA Class II antigens on MeWo and MeM 50-10 cells is an intrinsic property of each cell line, since only small differences were detected in the number and/or affinity of receptors on the two cell lines. Furthermore, the lack of marked effects of mezerein on the antigen-modulating activity of the three types of IFN, in spite of an enhancement of their differentiating activity, suggests that the changes in the antigenic profile induced by IFN do not represent a differentiation-related phenomenon.
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PMID:Modulation by interferons of HLA antigen, high-molecular-weight melanoma associated antigen, and intercellular adhesion molecule 1 expression by cultured melanoma cells with different metastatic potential. 249 70

A prospective pilot study on radioimmunoscintigraphy with monoclonal antibody fragments against cutaneous melanoma (MoAb 225.28S) was carried out in 17 patients with a clinical diagnosis of choroidal melanoma. Monoclonal antibodies against melanoma-associated antigen were labeled with 740 mBq 99mTc and injected IV; images were made with a gamma camera at 6 h after injection. With a double-pinhole collimator, radioactivity was counted thrice in both eyes at 6 h after injection. In 6 of 16 patients (37.5%), the melanoma could be imaged with the gamma camera. With the double-pinhole collimator, a significantly higher activity was measured in the melanomatous eye in 13 of 16 patients (82.4%). In two patients a false negative result was obtained, and in one patient the difference between the left and right eye was not significant. Considering these results, radioimmunoscintigraphy may be valuable in ocular melanoma diagnostics, but the specificity of MoAb 225.28S needs to be assessed.
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PMID:Radioimmunoscintigraphy with melanoma-associated monoclonal antibody fragments in choroidal melanoma. 250 Mar 85

Tumor necrosis factor (TNF-alpha) was compared to immune interferon (IFN-gamma) for its ability to modulate the expression and shedding of HLA antigens, of intercellular adhesion molecule I (ICAM I) and of high-molecular-weight melanoma-associated antigen (HMW MAA) by a panel of melanoma cell lines. The latter included the melanoma cell line MeWo and its metastatic variant MeM 50-10, which display differential susceptibility to modulation of HLA class-II antigens by IFN-gamma and the cell lines SK-MEL-93-DX-2 and SK-MEL-93-DX-3, which originated from anatomically distinct metastases in patient DX. TNF-alpha enhanced the expression of HLA class-I antigens on all 7 melanoma cell lines tested, although to a lower extent than IFN-gamma and the combination of IFN-gamma and TNF-alpha. TNF-alpha displayed a differential effect on the expression of HLA class-II antigens by the 7 melanoma cell lines: it enhanced it on 3 out of the 4 cell lines with constitutive expression of HLA class-II antigens and induced them on 1 of 3 cell lines without detectable expression of these antigens. The effects of IFN-gamma were different since it enhanced HLA class-II antigens on the 4 cell lines with constitutive expression of these antigens and induced them on 2 out of the remaining 3 lines. Interestingly, both TNF-alpha and IFN-gamma enhanced the expression of HLA class-II antigens by SK-MEL-93-DX-3 cells. On the other hand only TNF-alpha induced the expression of HLA class-II antigens by MeWo cells and only IFN-gamma induced such expression by MeM 50-10 cells and by SK-MEL-93-DX-2 cells. The effect of the combination of TNF-alpha and IFN-gamma was similar to that of the individual cytokines. Both TNF-alpha and IFN-gamma displayed a differential effect on the expression of the gene products of the HLA-D region by the melanoma cell lines. Northern blot analysis with HLA-DR beta-, DQ beta- and DP beta-specific probes suggests that the modulation of HLA class-II antigens by both cytokines reflects transcriptional and post-transcriptional events. TNF-alpha enhanced the expression of ICAM-I on all the melanoma cell lines, although to a lower extent than IFN-gamma and the combination of IFN-gamma and TNF-alpha. Lastly, neither TNF-alpha nor IFN-gamma displayed a marked effect on the expression of HMW-MAA by the melanoma cell lines tested.
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PMID:Differential modulation by tumor necrosis factor and immune interferon of HLA class-II antigens expressed by melanoma cells. 250 38

The restricted tissue distribution and the limited heterogeneity that appear in melanoma lesions of the high M.W. melanoma-associated antigen (HMW-MAA) suggest that this antigen may be an appropriate marker for radioimaging, and a useful target for immunotherapy in patients with melanoma. Therefore, in this study we analyzed other characteristics that are important in the selection of reagents for radioimaging and immunotherapy purposes. The affinities of the monoclonal antibodies (MoAB) 149.53, 225.28S, and 763.74T to distinct determinants of the HMW-MAA were found to be at least 1 X 10(8) mol/L. Furthermore, the effects of the concentrations of unlabeled MoAb on the dissociation rates suggest that the binding of MoAb 149.53 and 225.28S to melanoma cells (Colo 38) is preferentially bivalent, whereas that of MoAb 763.74T is preferentially univalent. These results suggest that the latter MoAb is the reagent of choice for assays that make use of soluble HMW-MAA, whereas the former two are the reagents of choice for assays with membrane-bound HMW-MAA, such as imaging with radiolabeled MoAb. The density of the HMW-MAA on cultured Colo 38 melanoma cells appears to be in the range of approximately 5 X 10(6) molecules/cell. The HMW-MAA was not susceptible to MoAb-mediated modulation under a variety of experimental conditions that included various concentrations of modulating MoAb, different incubation times, the use of an anti-mouse Ig antiserum, and the relaxation of equilibrium by diluting cells in MoAb-free medium. These results indicate that the HMW-MAA and the available corresponding MoAb meet the criteria to be reagents for radioimaging and immunotherapy in patients with melanoma.
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PMID:Analysis of the interaction between a human high molecular weight melanoma-associated antigen and the monoclonal antibodies to three distinct antigenic determinants. 258 52

Malignant transformation of melanocytes may be associated with changes in the expression of HLA antigens and melanoma-associated antigens (MAA). To determine whether these changes reflect the differential expression of HLA antigens and MAA by melanocytes at different stages of differentiation, we have studied the effect of the reversible induction of differentiation by fibroblast interferon (interferon beta) and/or 12-O-tetradecanoyl-phorbol 13-acetate (TPA) on the expression of HLA antigens and MAA by the melanoma cell lines DU-2, FO-1 and HO-1. The three melanoma cell lines differed in their sensitivity to the differentiating and antiproliferative activity of these two compounds and displayed an increased growth suppression and induction of differentiation, when incubated with the combination of TPA and interferon beta. Incubation of the three melanoma cell lines with interferon beta, TPA or their combination resulted in a differential modulation of the expression of membrane-bound high-molecular-mass melanoma-associated antigen, 115-kDa MAA, 100-kDa MAA, intercellular adhesion molecule 1, HLA class I antigens and gene products of the HLA-D region. Each melanoma cell line displayed a unique pattern of antigenic modulation when exposed to the two differentiating agents alone or in combination. No direct relationship was found between the effects of interferon beta and/or TPA on the growth and differentiation of the three melanoma cell lines and the expression of HLA antigens or the MAA evaluated in the present study. These findings argue against a direct role of any of the antigens tested in the reversible induction of human melanoma cell differentiation in the in vitro system.
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PMID:In vitro differentiation and antigenic changes in human melanoma cell lines. 262 19

F(ab')2 and Fab fragments of murine monoclonal antibody 9.2.27, that recognizes the 250 kD melanoma-associated antigen, were labeled with 99mTc using the bifunctional chelate method of Fritzberg et al. Twenty-seven (27) patients received, intravenously, 10 mg of either F(ab')2 (8), or the Fab (27), labeled with up to 30 mCi of 99mTc. These doses were preceded by an infusion of cold irrelevant antibody. The average serum T1/2 of the F(ab')2 and the Fab were 11 hr and 2 hr, respectively. Twenty-two percent (22%) of the total injected F(ab')2 dose was excreted in the urine in 20 hr, compared to 55% for the Fab group. Imaging was optimal 6-9 hr postinjection for the Fab patients. No nonspecific uptake in liver, spleen, bone marrow, or lung was observed for either antibody form. Overall, (43/53) 81% of known metastases were seen with visualization of tumors as small as 250 mg and tumor localization as high as 0.03% injected dose/g. Immunoperoxidase staining of freshly-frozen tumor nodules removed 24 hr postinjection confirmed antibody deposition in the tumor. Thirty-six previously unknown ("occult") metastatic sites were detected. To date, 12/36 of these sites have been confirmed. We conclude that 99mTc-labeled antibody to melanoma produces high resolution images with a high sensitivity of detecting metastatic melanoma. The detection of previously unknown sites of disease has proven helpful in directing additional diagnostic studies (i.e., CT) as well as planning of therapeutic options.
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PMID:Successful imaging of malignant melanoma with technetium-99m-labeled monoclonal antibodies. 264 54

Quantitative changes in the expression of two tumour-associated surface antigens on human FME melanoma cells were studied by flow cytometry after exposure to hypoxia and acidic pH, either alone or in combination. The expression of the p250 antigen recognized by the monoclonal antibody (MAb) 9.2.27 was reduced immediately after exposure to hypoxia. The magnitude and duration of the reduction increased with increasing exposure time. Twelve to 16 hr after the end of a 6-hr exposure to hypoxia the antigen expression reached the normal level, followed by a temporary increase above this level. The p97a antigen recognized by the 4.1 MAb underwent similar changes after exposure to hypoxia for 6 hr. After exposure to hypoxia in acidic environment, the magnitude and duration of the reduction in the expression of the p250 antigen increased with increasing acidity. The enhancement in antigen expression above the normal level was less after hypoxia at acidic pH than after hypoxia at physiological pH. The combined treatment had an additive effect on the expression of the melanoma-associated antigen but did not enhance hypoxia-induced cell killing. The observed changes in antigen expression might be of importance if hypoxic tumour cells are subjected to MAbs conjugated to radioisotopes or cytotoxic agents for diagnostic or therapeutic purposes.
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PMID:Changes in antigen expression on human FME melanoma cells after exposure to hypoxia and acidic pH, alone or in combination. 264 23

NGA is a human melanoma-associated antigen recognized by a panel of murine monoclonal antibodies developed in this laboratory. NGA consists of a 23.5 kDa core protein which is glycosylated in vivo to give a family of glycoproteins (30-60 kDa). Treatment of human melanoma G361 cells with the phorbol ester PMA resulted in apparent partial inhibition of NGA glycosylation. After PMA treatment, NGA appeared as 3 different bands of 24, 29 and 34 kDa on SDS-PAGE. The 29 kDa band is similar to the one obtained by treatment with the ionophore monensin, which inhibits NGA O-glycosylation. PMA can modulate plasma membrane ion exchange, most likely by activating protein kinase C. In G361 cells PMA may produce the same net effect as monensin, by impairing transport in the Golgi complex and consequently inhibiting protein O-glycosylation through an ionophore-like effect. Treatment of G361 cells with both PMA and protein kinase C inhibitors re-established the usual NGA glycosylation pattern. Thus the observed effect of PMA on NGA glycosylation is reversible and appears to be mediated by protein kinase C activation.
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PMID:Inhibition of neuroglandular antigen (NGA) glycosylation by phorbol ester in human melanoma cells. 264 70

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