Figure 2

Differential sensitivity of MDA-MB-231 and MCF-7 to DCQ-induced apoptosis. (A) Cells were treated with DCQ for 6 hours under normoxia or hypoxia. After 24 hours, the extent of DNA fragmentation was determined by TUNEL assay and measured by flow cytometry. (B) Cells were treated with DCQ for 6 hours under normoxia or hypoxia. After 24 hours control and DCQ treated cells were stained with fluorescein-conjugated annexin V and PI; apoptotic and necrotic cells were analyzed by flow cytometry. The percentage of apoptotic cells was determined in response to DCQ using CellQuest software and the averages ± SE were obtained from the results of three independent experiments each done in duplicate. Two sample t-test was used to compare between the effect of DCQ under normoxia versus hypoxia under the same concentration, p < 0.05 is indicated by †. The effect of the same concentration of DCQ (3 μM and 5 μM) on the two cell lines was compared by t-test. MCF-7 cells were more resistant to DCQ apoptotic effect than the MDA-MB-231 (p < 0.05).