Highly altered protein expression profile in the adriamycin resistant MCF-7 cell line

The protein expression pattern in the cytosol fraction of the adriamycin resistant MCF-7 cell line (MCF-7/ADR) was compared to that of the parental MCF-7 cell line using two-dimensional gel electrophoresis and mass spectrometry. Twenty proteins with altered abundances were identified and studied in MCF-7/ADR. Both up regulation and down regulation are characterized. The most striking differences were found for proteins that were uniquely expressed in this cell line and not detectable in the parental MCF-7 cell line. These proteins include annexin 1, the neuronal ubiquitin carboxyl hydrolase isoenzyme L-1 (also known as PGP9.5), glutathione-S-transferase pi class, nicotinamide N-methyltransferase, and interleukin-18 precursor. On the other hand, catechol-O-methyltransferase was expressed in the parental cell line, but was not detected in the adriamycin resistant cell line. This protein expression pattern was unique to MCF-7/ADR and not observed in MCF-7 cell lines selected for resistant to etoposide, mitoxantrone or melphalan.