A Potential Peptide Therapeutic Derived from the Juxtamembrane Domain of the Epidermal Growth Factor Receptor
Serum starved (A) MDA-MB-231 cells or (B) SK-N-MC cells were treated overnight with 5, 10 or 20 µM of TE-64562 for 0.5, 1 or 3 hours and assayed for cell viability. Data were averaged from three independent experiments and plotted with the error bars representing the standard deviation from the mean. Significant differences were assessed between each treatment condition and untreated control (*P<0.05 from a two-tailed unpaired t test). (C) MDA-MB-231 breast cancer cells were serum starved overnight then treated with 0 (control), 6 or 12 µM TE-64562 for 18 hours. Cells were stained with Annexin-V and propidium iodide (PI) and the mean results from four independent experiments are plotted. Unstained cells represent viable cells; total Annexin V staining (Anx-V) is the sum of the Anx-V-stained and dually stained cells which are undergoing apoptosis or are fully apoptotic or necrotic; and Anx-V only stained cells are undergoing apoptosis. Significant differences were assessed between each treatment condition and untreated control (*P = 0.028; **P = 0.008; ***P = 0.004). (D) Serum starved MDA-MB-231 cells were treated with 0 (control), 3, 6 or 12 µM TE-64562 for 18 hours. Cells were lysed, analyzed by Western blot and probed for the presence of cleaved caspase-3. Numbers below the blot images represent the quantifications of each band normalized to the respective control. The blot is representative of two independent experiments. All error bars represent standard error of the mean. Also see Figure S3.