FIGURE 3.
Ability of truncated and variant RasGAP317–326 peptides to increase adherence, inhibit cell migration, and sensitize cancer cells to cisplatin-induced apoptosis. A, sequences of the peptides tested. Residues shaded in gray are those that are found required for adhesion based on the alanine-scanning performed in Fig. 1. The residues in white on a black background are those that differ from the residues shaded in gray. Droso, Drosophila. B, U2OS cells were cultured overnight and were subsequently treated for 8 h with 20 μm TAT or 20 μm of the indicated TAT-coupled peptides or left untreated. The cells were then subjected to trypsin-mediated detachment assays. Error bars indicate mean ± 95% confidence intervals, C, U2OS cells were subjected to wound-healing scratch assays in the presence of 20 μm of the indicated TAT-coupled peptides. Asterisks and number signs denote statistical significant differences after one-way ANOVA from the untreated condition and from the 317–326 treatment, respectively (n = 7 independent experiments). Error bars indicate mean ± 95% confidence intervals, D, U2OS cells were cultured overnight and were subsequently treated for 22 h with 20 μm of the indicated TAT-coupled peptides in the presence or in the absence of 30 μm cisplatin. The number of pyknotic nuclei was then scored and reported as the percentage of apoptosis. The light gray region displays the level of apoptosis induced by cisplatin alone, and the dark gray region shows the zone where sensitization occurs. Asterisks and number signs denote statistical significant differences after one-way ANOVA with the cisplatin-only treatment and with the cisplatin + 317–326 treatment, respectively (n = 6 independent experiments). Error bars indicate mean ± 95% confidence intervals.