TRANSLATION INITIATION-FACTOR EIF-4A1 MESSENGER-RNA IS CONSISTENTLY OVEREXPRESSED IN HUMAN-MELANOMA CELLS IN-VITRO

The oncogenic potential of translation initiation factors (eIF-4E and eIF-2 alpha) has been described in previous studies leading to the def inition of translational oncogenes. Two previously isolated cDNA clone s, expressed differently in human melanoma cells and normal human mela nocytes, were identified in this study as coding for the translation i nitiation factor eIF-4A1. Northern-blot analysis revealed consistent o verexpression of eIF-4A1 mRNA in a panel of 14 melanoma cell lines (on an average 5.6 times higher than in cultures of normal human melanocy tes). In contrast, the mRNAs of the other group-4 translation initiati on factors (eIF-4A2, eIF-4B, eIF-4E and eIF-4 gamma) were less and not consistently elevated. Cultures of congenital melanocytic nevi exhibi ted inter mediate expression of eIF-4A1. Thus, eIF-4A1 overexpression seems to be an important feature of melanoma cells and might contribut e to their malignant transformation. (C) 1997 Wiley-Liss, Inc.