Fig. 4.

Combination treatment with parthenolide and radiation synergistically inhibits growth and induces apoptosis in LM7 osteosarcoma cells. LM7 cells were treated with either DMSO or parthenolide at 10 µM, DMSO and 10Gy ionizing radiation or both parthenolide and radiation. In the latter parthenolide was added 4 hrs before irradiation. At 24 hrs after irradiation cells were collected. A) LM7 cells were detached and counted in a CelloMeter automatic cell counter. B) After treatments LM7 cells were stained with Hoechst33342. The number of cells with condensed apoptotic nuclei was counted against the total number of cells. C) After treatments LM7 cells were fixed and incubated with PE-conjugated anti-active caspase-3 antibody and assayed using flow cytometry. PE positive cell counts of treated cells were compared to those of untreated cells, and plotted as average fold change. D) Cells were stained with propidium iodide and subjected to flow cytometry to determine cell cycle distribution. Box insert shows representative flow cytometry histogram. Data are Means ± SE (n=4). * indicates P<0.05 when compared to cells exposed only to radiation. # indicates P<0.05 when compared to cells treated with parthenolide alone.