TRAIL-Induced Breast Cancer Cytotoxicity

Cells were seeded into monolayer or suspension for 7 days, at which point the cells were isolated, using a non-enzymatic dissociation buffer (CellStripper, Invitrogen, Carlsbad, CA, USA), and re-seeded into either the tissue culture polystyrene or the Ultra-Low Attachment 96 well plates, at a concentration of 10,000 cells/well. Cells were maintained in a complete medium, overnight, prior to the TRAIL treatment. The cells were treated with the recombinant human TRAIL (TRAIL) (R&D Systems, 375-TEC), at two different doses (10 ng/mL and 100 ng/mL for MDA-MB-231 and ZR75-1 cell lines; 50 ng/mL and 500 ng/mL for MCF7 cell lines). The concentrations were based on our previous research, in which the IC50 for TRAIL treatment over 24 h was found to be 1–5 ng/mL for MDA-MB-231, 7–8 ng/mL for ZR75-1, and >500 ng/mL for MCF7 cells [37 (link)]. Plates were incubated with TRAIL over 24 h and analyzed for either viability or protein expression, at indicated timepoints.