Characterization of melanoma-associated surface antigens involved in the adhesion and motility of human melanoma cells (original) (raw)
1986, International Journal of Cancer
The functional properties of the melanoma-associ ated antigens detected by monoclonal antibodies (MAbs) A M F-6 and A M F-7 w ere investigated. These MAbs w ere selected previously because of their capac ity to block the anti-m elanom a reactivity of cytotoxic T-lymphocyte clones A M F-6 and AMF-7 detect a me(anoma-associated proteoglycan (M W > 450-250 kDa) and a molecular complex, which under reducing con ditions consists of 4 compounds of 120, 95, 29 and 25 kDa respectively. A M F-6 reacted strongly with all 30 cultured melanomas and all 41 melanomas in frozen tissue sections. Significant cross-reactivity was only observed with nevi and perineurium, whereas normal skin melanocytes w ere negative. AMF-7 reacted with all 25 cultured melanomas and all 34 melanomas in frozen sections. A M F-7 cross-reacted with a propor tion of nevi and endothelial cells from small vessels. The antigen detected by A M F-6 and AMF-7 could not be modulated by retinoic acid or recombinant 7-IFN, which induced or enhanced the expression of HLA-DR, H L AD Q and Class-1 M H C antigens. In addition, the antigens w ere not readily modulated when cells were incubated in excess amounts of A M F-6 and AMF-7. Interestingly, the antigen detected by AMF-7 was strongly associated w ith the adhesion and cytoplasmic spreading of m elanom a cells to plastic surfaces and monolayers of vascular endothelial cells. A M F-6 did not block the adhesion of melanoma cells but delayed cytoplasmic spreading. Both A M F-6 and AMF-7 blocked fibronectin-induced chemotaxic m otility and chemokinesis of m elanom a cells. In addition to their m em brane localization, the antigens detected by AMF-6 and AM F-7 w ere also abundant in extracellular adhe sion plaques deposited by cultured melanoma ceils. O u r results indicate th at the high-MW melanomaassociated proteoglycan and the antigen detected by A M F-7 are associated w ith adhesion and/or cyto plasmic spreading and m o tility of human melanoma cells, suggesting that these antigens ¿ire associated with the (hematogenic) dissemination of human mela noma« This is supported by the finding that AMF-7 stained prim ary tum ors heterogeneously, whereas metastases w ere homogeneously stained.
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