CORRELATION BETWEEN THE EXPRESSION OF KI67 AND HLA-DR ANTIGENS IN FOTEMUSTINE-TREATED MELANOMA CELL-LINES

We studied the effect of fotemustine (FM) on the expression of several melanoma-associated antigens (MAA) and HLA antigens defined by a pane l of seven monoclonal antibodies (mabs). We also leaked for the effect of the culture conditions on the antigen expression. We used eight es tablished melanoma cell Lines, grown as monolayers in (a) modified Lei bowitz L15 medium for 0, 48, 96 h; (b) with 12.8 mu g/ml fotemustine f or 48 h; (c) with 12.8 mu g/ml fotemustine for 48 h followed by incuba tion with modified Leibowitz L15 medium for another 48 h. Incubation o f melanoma cell lines for 48 or 96 h in growth medium (a) resulted in a modest upregulation elf the transferrin receptor (TFR), the very lat e antigen 2 (VLA-2), and the intercellular adhesion molecule 1 (ICAM-1 ) in the majority of our cell Lines. Following the addition of FM (b) no relevant change in the antigen expression was observed during conti nuous incubation for 48 h. However. an additional incubation of the FM -treated melanoma cells for another 48 h in FM-free medium (c) showed a striking upregulation of TRI, VLA-2 and ICAM-1. Furthermore, the nuc lear proliferation-associated antigen detected by Ki67 was upregulated markedly only in the presence of at least 80% HLA-DR-positive cells.