Targeted optical imaging of cancer cells using lectin-binding BODIPY conjugated avidin

Lectins (asialo-receptor family) are expressed on a number of tumors that develop peritoneal metastases. To demonstrate that fluorescence imaging based on lectin binding is applicable for a variety of tumors, we conjugated BODIPY to avidin (avidin–BODIPY), and studied the efficacy of tumor targeting in 9 cancer cell lines in vitro and an ovarian cancer cell line in vivo using a murine peritoneal cancer model. All 9 cell lines showed specific intracellular accumulation with avidin–BODIPY on fluorescence microscopy and flow cytometry. In vivo spectral molecular imaging clearly visualized the peritoneal tumor foci with avidin–BODIPY, whereas, deglycosylated avidin–BODIPY (neutravidin–BODIPY) showed only minimal fluorescence from the tumor foci and was accompanied by higher background signals. These results suggest the lectin-targeted molecular imaging technique using a targeted green fluorescence probe is potentially useful in a wide variety of cancers with a proclivity for dissemination in the peritoneal space.