Changes in gene expression profile in two multidrug resistant cell lines derived from a same drug sensitive cell line

• K562-derived MDR cell lines shared changes in some biological functions.
• The number of differentially expressed genes was different for each derived cell line.
• In both K562-derived MDR cell lines ABCB1 was overexpressed in respect to K562.
• In both K562-derived MDR cell lines the ABCB1 promoter was totally demethylated.
• Our findings showed that NOTCH pathway was affected in both K562-derived MDR cells.

Resistance to chemotherapy is one of the most relevant aspects of treatment failure in cancer. Cell lines are used as models to study resistance. We analyzed the transcriptional profile of two multidrug resistant (MDR) cell lines (Lucena 1 and FEPS) derived from the same drug-sensitive cell K562. Microarray data identified 130 differentially expressed genes (DEG) between K562 vs. Lucena 1, 1932 between K562 vs. FEPS, and 1211 between Lucena 1 versus FEPS. The NOTCH pathway was affected in FEPS with overexpression of NOTCH2 and HEY1. The highly overexpressed gene in MDR cell lines was ABCB1, and both presented the ABCB1 promoter unmethylated.