Figure 2.

In vitro fluorescence studies of PSMA-1-MMAE-Cy5.5 conjugates. In vitro cellular uptake results of PSMA-targeted drug conjugates. Cells were incubated with 50 nM of drug conjugates for 4 h. Nuclei were stained by DAPI and are false colored blue, lysosomes were detected by LysoOrange and are false colored green, and drug conjugates are false colored red. Selective uptake was observed only in PC3pip cells and the conjugates were mainly located in lysosomes. Specificity of drug conjugates for PSMA binding was evaluated by including 1 mM of unlabeled PSMA-1 ligand during incubations. Signal in PC3pip cells was significantly competed by PSMA-1, suggesting the binding is selective. Images are taken at 40×. Representative images are shown from three independent experiments.