Identification of novel proteins associated with the development of chemoresistance in malignant melanoma using two-dimensional electrophoresis

A model system for studying chemoresistance in human melanoma cells (MeWo) has been established utilizing the four commonly used cytotoxic drugs vinde sine, cisplatin, fotemustine and etoposide to yield stable drug-resistant s ublines. We analyzed phenotypical differences between MeWo cells and their chemoresistant counterparts using two-dimensional electrophoresis. Proteins that were overexpressed in chemoresistant cell lines were purified and ide ntified using matrix assisted laser desorption/ionization-time of flight - mass spectrometry (MALDI-TOF-MS) and microsequencing. Here we show that fou r proteins, namely the translationally controlled tumor protein, the human elongation factor 1-delta, tetratricopeptide repeat protein and the isoform 14-3-3-gamma of the 14-3-3-family are overexpressed in chemoresistant mela noma cell lines. The significance of these findings is now being verified u sing transfection experiments with the aim of developing more effective che motherapy protocols.