S100A8 was elevated in drug resistance leukemia cells and chemotherapy agents induced S100A8 expression in leukemia cells.

<p>(<b>A</b>) Protein level of S100A8 was analyzed by Western blotting in Jurkat, HL-60, K562 and MV4-11 cells (n = 3, ^*<i>P</i><0.05). (<b>B and C</b>) S100A8 mRNA level in leukemia cells was analyzed by real time RT-PCR (n = 3, ^*<i>P</i><0.05 versus Jurkat cells in <b>B</b> and ^*<i>P</i><0.05 versus HL-60 or K562 in <b>C</b>, Jurkat group set as 1). (<b>D</b>) Basal LC3-I/II level was analyzed by Western blotting in leukemia cells (n = 3, ^*<i>P</i><0.05 <i>versus</i> Jurkat cells ). (<b>E and F</b>) IC50 levels of adriamycin (ADR) in Jurkat, K562, HL-60, MV-4-11, K562/A02, and HL-60/ADR cells (n = 3, ^*<i>P</i><0.05 versus Jurkat cells in <b>E</b>, ^*<i>P</i><0.05 versus HL-60 or K562 in <b>F</b>). (<b>G</b>) Jurkat, HL-60, K562 and MV4-11 cells were treated with ADR (1 µg/ml), VCR (1 µg/ml) or As2O3 (5 µM) for 24 hours and S100A8 protein level was analyzed by Western blotting (n = 3, *P<0.05 vs. UT, untreated group). AU, arbitrary unit. (<b>H</b>) Jurkat, HL-60, K562 and MV4-11 cells were treated with ADR (1 µg/ml), vincristine (VCR, 1 µg/ml) or arsenic trioxide (As2O3, 5 µM) for 24 hours and S100A8 mRNA level was analyzed by real time RT-PCR (n = 3, *P<0.05 versus control group, control group set as 1).