IV/GG substitution abolishes BH4-Bcl-2’s protective function against STS-induced apoptosis.

Simultaneous analysis of caspase activation (FITC-VAD-FMK, green) and nuclear fragmentation (DAPI staining, blue fragments) of STS-treated C6 glioma cells. (A) Representative images of cells electroporated with or without BH4 peptides (20 µM) and successively treated with STS (2 µM for 6 h). The left images are taken outside the electroporation area and are used as negative controls (A, upper right). Electroporation in the absence of peptides (vehicle) (A, middle right). Electroporation of Bcl-2-BH4 peptide (A, lower right). Electroporation of Bcl-2-BH4-IV/GG peptides. Red color is due to the spillover into the FITC channel of the intense DTR signal (the electroporation loading control). (B) Quantitative image based AI (number of apoptotic cells divided by the total cell number). The AI was normalized to the AI outside the electroporated area. All results were obtained from 5 independent experiments and are plotted as means ± SEM. Only Bcl-2-BH4 loading significantly reduced the AI when compared with the control vehicle (**). ### indicates that the results obtained with Bcl-2-BH4 IV/GG were significantly different from Bcl-2-BH4.