title: Differential induction of apoptosis in human breast cancer cell lines by phenethyl isothiocyanate, a glutathione depleting agent.
abstract: Phenethyl isothiocyanate (PEITC) is a naturally occurring electrophile which depletes intracellular glutathione (GSH) levels and triggers accumulation of reactive oxygen species (ROS). PEITC is of considerable interest as a potential chemopreventive/chemotherapeutic agent, and in this work, we have investigated the effects of PEITC on human breast cancer cell lines. Whereas PEITC readily induced apoptosis in MDA-MB-231 cells (associated with rapid activation of caspases 9 and 3, and decreased expression of BAX), MCF7 cells were relatively resistant to the apoptosis promoting effects of PEITC. The relative resistance of MCF7 cells was associated with high basal expression of NRF2, a transcription factor that coordinates cellular protective responses to oxidants and electrophiles and raised intracellular levels of GSH. This raised basal expression of NRF2 appeared to be a response to on-going production of ROS, since treatment with the antioxidant and GSH precursor N-acetylcysteine (NAC) reduced NRF2 expression. Moreover, pre-treatment of MDA-MB-231 cells with NAC rendered these cells relatively resistant to PEITC-induced apoptosis. In summary, our data confirm that PEITC may be an effective chemopreventive/therapeutic agents for breast cancer. However, differences in the basal expression of NRF2 and resultant changes in GSH levels may be an important determinant of sensitivity to PEITC-induced apoptosis.
authors.affiliation: Cancer Research UK Centre, Cancer Sciences Unit, University of Southampton Faculty of Medicine, Southampton General Hospital, UK.
authors.forename: Sharifah S
authors.initials: SS
authors.lastname: Syed Alwi
authors.forename: Breeze E
authors.initials: BE
authors.lastname: Cavell
authors.forename: Alison
authors.initials: A
authors.lastname: Donlevy
authors.forename: Graham
authors.initials: G
authors.lastname: Packham
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D020169:Caspases / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D005260:Female; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D017879:Isothiocyanates / Q000494:pharmacology*; D061986:MCF-7 Cells; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D016588:Anticarcinogenic Agents; D017879:Isothiocyanates; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; C058305:phenethyl isothiocyanate; D020169:Caspases; D005978:Glutathione