Figure 2
Eradication of MCF-7 and MDA231 human breast cancer cells by phenanthridine-derived PARP inhibitors. (a) MCF-7 cells were seeded (about 500,000/well) in six-well plates and incubated for 48 hours with the potent PARP inhibitors, PJ-34 (10 μM), Tiq-A (50 μM), and Phen (25 μM), each applied (a single application) 24 hours after seeding. Cells were counted and pictured under a microscope (0.02 to 0.03 mm2 per field). Control (upper left) and treated MCF-7 cells are presented, 72 hours after seeding. These representative results were repeated in five different experiments. (b) Survival rate (percentage relative to untreated cells at each time point, control) of MCF-7 breast cancer cells after incubation for 48 hours with several concentrations of PJ-34, applied (a single application) 24 hours after seeding. Each value represents the average value of five measurements in different cell cultures. (c) Colony formation (percentage relative to colony formation of untreated cells) of MCF-7 breast cancer cells reseeded and incubated for 2 additional weeks in the absence of PJ-34, 48 hours after a single application of PJ-34 at several concentrations was applied 24 hours after the initial seeding (Methods). Each value represents the average value of three measurements in three different experiments. (d) Left panel: MDA231 breast cancer cells were seeded (about 500,000/well) in six-well plates. PJ-34 was applied into the medium at the indicated final concentrations 24 hours after seeding. Cells were counted and pictured under microscope (0.02 to 0.03 mm2 per field). Right panel: Survival rate (percentage relative to untreated cells at each time point, control) of MDA231 breast cancer cells after 72 hours of incubation with several concentrations of PJ-34, applied (a single application) 24 hours after seeding. Each value is an average of three measurements obtained in three different experiments.