[Development of a K562 multidrug-resistant cell line and study on proteins with altered expression].

In an attempt to study the whole protein expression alterations of tumer cells after becoming multidrug-resistant, which may provide useful information on new drug target identification, an adriamycin-resistant variant of the human leukemia cell line K562 (K562/ADR) was developed in vitro by continuous exposure to adrimycin. MTT assay was used to determine IC50 of K562/ADR cells to adriamycin (ADR), cisplatin (DDP), 5-fluorouracil (5-FU) and vincristin (VCR). The total proteins of K562 and K562/ADR were separated by two-dimensional gel electrophoresis and visualized by silver staining. Proteins with significant expression alterations were selected and their peptide mass fingerprints (PMFs) were obtained by matrix-assisted laser desorption/ionization time of flying mass spectrometry (MALDI-TOF-MS). The PMFs were used to search NCBInr database by AutoMS-Fit software. The results showed that K562/ADR cell demonstrated cross-resistance to other antineoplastic drugs. The IC50 of K562/ADR cells to ADR, DDP, 5-FU, VDR were much higher than those of K562. The proteins differentially expressed in the two cell lines were identified as cell cycle-related proteins, zinc finger protein 165, etc. These proteins are involved in cell cycling and transcription regulation, whose expression alterations may contribute to the multidrug resistant phenotype of K562/ADR cells.