Figure 4

Catechins induced apoptosis in primary APL cells without affecting the proliferation capacity of normal hematopoietic progenitor cells. (A) Catechins inhibited growth of primary leukemia cells from patients with APL by MTT assay. Cells were treated with 100 μM and 200 μM Catechins for 24 h and 48 h. (B) Catechins induced apoptosis of primary leukemia cells from three patients by morphological study. Cells were treated with 100 μM and 200 μM Catechins for 24 h. (C) Apoptosis was evaluated by Annexin V/PI double staining and showed the fold-increase of apoptotic cells in all three cases. Cells were treated with 100 μM and 200 μM Catechins for 24 and 48 h. **P < 0.01 comparing with the untreated cells. (D) Intracellular levels of ROS were measured by flow cytometry in all three cases. Cells were treated with 200 μM Catechins for 2 h. *P < 0.05 comparing with the untreated cells. (E) The PML-RARα oncoprotein was degraded in primary leukemia cells treated with 100 μM and 150 μM Catechins for 24 h. (F) The proliferation of normal hematopoietic progenitor cells was not inhibited by Catechins up to 800 μM. CD34+ cells enriched from cord blood samples (n = 3) were cultured in the presence of Catechins at the indicated concentrations for 72 h. The cell viability was measured by MTT assay.