Apoptotic mechanisms in T47D and MCF-7 human breast cancer cells

Br J Cancer. 2002 Oct 7;87(8):909-17. doi: 10.1038/sj.bjc.6600541.

Abstract

To investigate the mechanisms underlying apoptosis in breast cancer cells, staurosporine was used as an apoptotic stimulus in the human breast cancer cell lines MCF-7 and T47D. Staurosporine induced dose and time dependent increases in DNA fragmentation which was abrogated by z-VAD-fmk. MCF-7 cells did not express caspase-3, suggesting that DNA fragmentation occurred in the absence of caspase-3 and that other caspases may be involved. Staurosporine induced DEVDase activity in T47D cells suggesting the involvement of caspase-3 and/or caspase-7, yet there was no DEVDase activity in MCF-7 cells, probably ruling out the involvement caspase-7. However, staurosporine induced the cleavage of pro-caspase-6 in MCF-7 cells, but not in T47D cells. Caspase dependent PARP cleavage was detected in MCF-7 cells at 3 h, whereas only partial PARP cleavage was detected in T47D cells and then only after 24 h. Moreover, staurosporine led to cytochrome c release at 2 h in MCF-7 cells and 6 h in T47D cells. In addition, a time dependent and caspase-independent reduction of the mitochondrial transmembrane potential was observed; which appeared to occur after the release of cytochrome c. Translocation of Bax from the cytosol to mitochondria was observed in both cell types, and this preceded cytochrome c release in both T47D and MCF-7 cells. Apoptotic events in both cell types differ temporally, involving activation of different caspases and mitochondrial changes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Chloromethyl Ketones
  • Apoptosis* / drug effects
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • Caspase Inhibitors
  • Caspases / metabolism*
  • Cytochrome c Group / metabolism
  • Enzyme Activation
  • Enzyme Inhibitors / pharmacology
  • Humans
  • In Situ Nick-End Labeling
  • Membrane Potentials / drug effects
  • Membrane Proteins / metabolism
  • Mitochondria / drug effects
  • Mitochondria / physiology
  • Poly(ADP-ribose) Polymerases / metabolism
  • Protein Transport
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Staurosporine / pharmacology
  • Tumor Cells, Cultured / drug effects
  • Tumor Cells, Cultured / metabolism
  • Tumor Suppressor Protein p53 / metabolism*
  • bcl-2 Homologous Antagonist-Killer Protein
  • bcl-2-Associated X Protein
  • bcl-X Protein

Substances

  • Amino Acid Chloromethyl Ketones
  • BAK1 protein, human
  • BAX protein, human
  • BCL2L1 protein, human
  • Caspase Inhibitors
  • Cytochrome c Group
  • Enzyme Inhibitors
  • Membrane Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Tumor Suppressor Protein p53
  • bcl-2 Homologous Antagonist-Killer Protein
  • bcl-2-Associated X Protein
  • bcl-X Protein
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • Poly(ADP-ribose) Polymerases
  • Caspases
  • Staurosporine