HNK-1 ANTIGENS ON UVEAL AND CUTANEOUS MELANOMA CELL-LINES

The HNK-1 epitope has been associated with the metastatic behaviour of uveal melanomas. We characterized HNK-1 antigens on four human uveal (primary and metastatic) and two primary cutaneous melanoma cell lines by immunocytochemistry and Western blot analysis. We also determined the involvement of the HNK-1 epitope in cell-cell interactions on a ma trigel layer. Three uveal melanoma cell lines (one primary and two met astatic) and one cutaneous melanoma cell line showed HNK-1 expression by immunocytochemistry. On matrigel, only the HNK-1-positive cutaneous melanoma cell line Bowes grew in a honeycomb-like structure which dis appeared after adding HNK-1 antibodies to the culture medium. Immunobl ot analysis of the primary uveal melanoma cell line EOM-3 revealed fiv e HNK-1-positive protein bands with apparent molecular weights of 200, 160, 115, 95 end 75 kDa. The cutaneous melanoma cell line Bowes showe d three HNK-1-positive protein bands with apparent molecular weights o f 150, 135 and 90 kDa. This study shows that two uveal (primary and me tastatic) and one primary cutaneous melanoma cell lines express HNK-1 antigens on immunoblot. Only in the HNK-1-positive cutaneous melanoma cell line Bowes did the HNK-1 epitope have a function in intercellular adhesion. Although the primary uveal melanoma cell line EOM-3 showed a similar HNK-1 immunoreactivity, we could not demonstrate HNK-1-media ted cell adhesion. On immunoblot, the two cell lines displayed differe nt HNK-1 antigens, which may explain the difference in cell adhesion.