Confocal microscopy analysis of intracellular distribution of FITC-conjugated CPE peptide in OSPC-ARK-1. Tumor cells were obtained, exposed to FITC-conjugated CPE peptide and then evaluated by confocal microscopy (upper panel) and three-dimensional (3D) image reconstruction (lower panel). Images were reconstructed from confocal micrographs taken every 4 μm from the bottom of the culture slide up, and all views are perpendicular to the plane of the culture slide. Green fluorescence represents tumor staining with FITC-conjugated CPE peptide. The figures depict images reconstructed from multiple optical sections (total 40 μm) through the entirety of the cells. The upper panel figure shows corresponding images of the same cells at different levels of optical sectioning, and serves to highlight the "appearance" of FITC-conjugated CPE peptide material within the cytoplasm. In the lower panel representative 3D reconstruction images are shown, demonstrating dense aggregates of FITC-conjugated CPE peptide after 24 hours of peptide exposure in the cytoplasm of OSPC-ARK-1 cells.