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.