Figure 5.

Apoptosis induced after serum deprivation by depletion of c-Myc in MCF-7 cells. (a) Downregulation of c-Myc promoted apoptosis of MCF-7 cells after serum deprivation. MCF-7 cells were transfected with pSilencer–c-Myc or pSilencer. After 24 hours, cells were deprived of serum for 36 hours. Cells were then collected by trypsinization. The apoptotic cells were determined by flow cytometry. The cell population in sub-G1 is shown. The x and y axes show DNA content and cell number, respectively. (b) TUNEL assay to detect apoptotic cells in situ. MCF-7 cells were grown on coverslips and transfected with pSilencer–c-Myc or pSilencer. After 24 hours, cells were deprived of serum for 36 hours. Cells were then analyzed for apoptosis with the TUNEL assay. Dark-blue staining of nuclei indicates apoptosis. Arrows indicate representative TUNEL-positive cells.