A Potential Peptide Therapeutic Derived from the Juxtamembrane Domain of the Epidermal Growth Factor Receptor
(A) The Tat-conjugated EGFR JMA peptide (TE-64562) was added to the MDA-MB-231 cells, in 2.5% serum (gray triangles) or serum free media (black squares). The non-Tat-conjugated EGFR JMA peptide (E-645-662, diamonds), the Tat peptide (Tat, black circles) or Tat-conjugated EGFR JMB peptide (TE-66482, black inverted triangles) were added to the MDA-MB-231 cells in serum free media. The cell viability, measured after overnight treatment, is plotted. The plot represents one of three independent experiments, run in triplicate. Error bars represent standard error of the mean of triplicate values from one experiment. (B–D) Peptides were N-terminally labeled with 5-carboxyfluorescein (FAM). (B) MDA-MB-231 cells were treated with FAM-TE-64562 (1.25 µM) for the indicated amounts of time. Scale bar = 15 µm. (C) Cells were treated overnight with FAM-TE-64562 (5.0 µM), FAM-645-662 (5.0 µM), FAM-Tat (2.5 µM) or FAM-664-682 (5.0 µM) and imaged the following day. Scale bars are 40 µm. Also see Figure S1.