Nanoparticles for the Optical Imaging of Tumor selectin

We designed a fluorescent peptide-magnetic noneparticle conjugate that images selectin expression in mouse xenograft models of Lewis lung carcinoma. (LLC) by fluorescence reflectance imaging. It was synthesized by attaching the selectin-binding peptide. (ESBP; CDSBSDITWDOLWDLMK) to a CLIO(Cy5.5) nanoparticle to yield ESBP-CLIO(Cy5.5). Internalization by activated human umbilical vein endothelial cells. (HUVECs) was rapid and mediated by selectin, indicated by the lack of uptake of nanoparticles bearing similar numbers of a scrambled peptide. (Scram). To demonstrate the specificity of selectin targeting to ESBP-CLIO(Cy5.5) in vivo, we coinjected ESBP-CLIO. (Cy5,5) and Scram -CLIO(Cy3,5) and demonstrated a high Cy5.5/Cy3.5 fluorescence ratio using the LLC. Histology showed that ESBP-CLIO was associated with tumor cells as well as endothelial cells, but fluorescenceactivated cell sorter analysis showed afar less expression of selectin on LLC than on HUVECs. Using immunohistochemistry, we demonstrated selectin expression in both endothelial cells and cancer cells in human prostate cancer specimens. We conclude that ESBP-OLIO. (Cy5Z) is a useful probe for imaging selectin associated with the LLC tumor, that selectin is expressed not only on endothelial cells but also on LLC cells and human prostate cancer specimens.