Figure 5.

(A) (–)‐Epigallocatechin‐3‐gallate (EGCG) enhanced imatinib‐induced cell death. K562 cells were seeded at a density of 5 × 10³ cells per well in 96‐well plates, and cultured with EGCG and imatinib alone/or in combination for 48 h. The number of viable cells were measured based on intracellular ATP content, and expressed as a percentage of 0.1% ethanol‐treated control cells. Results are means ± standard deviation (SD) of three independent experiments. Two asterisks indicate significant difference from the corresponding dose of single imatinib treatment (P < 0.01) and one asterisk indicates significant difference of P < 0.05. (B) EGCG was equally effective to induce cell death in imatinib‐resistant chronic myelogenous leukemia (CML) cells. Imatinib‐resistant K562 (K562/sti) cells were seeded at a density of 5 × 10³ cells per well in 96‐well plates, and treated with increasing concentrations of EGCG or imatinib for 48 h, and the number of viable cells were measured based on intracellular ATP content. Viable cells are expressed as a percentage of 0.1% ethanol‐treated control cells for each cell line. Values are representative of three independent experiments.