Biotinylated Bioluminescent Probe for Long Lasting Targeted in Vivo Imaging of Xenografted Brain Tumors in Mice

Bioluminescence is a useful tool for imaging of cancer in in vivo animal models that endogenously express luciferase, an enzyme that requires a substrate for visual readout. Current bioluminescence imaging, using commonly available luciferin substrates, only lasts a short time (15–20 min). To avoid repeated administration of luciferase substrate during cancer detection and surgery, a long lasting bioluminescence imaging substrate or system is needed. A novel water-soluble biotinylated luciferase probe, B-YL (1), was synthesized. A receptor-targeted complex of B-YL with streptavidin (SA) together with a biotinylated epidermal growth factor short peptide (B-EGF) (SA/B-YL/B-EGF = 1:3:1, molar ratio) was then prepared to demonstrate selective targeting. The complex was incubated with brain cancer cell lines overexpressing the EGF receptor (EGFR) and transfected with the luciferase gene. Results show that the complex specifically detects cancer cells by bioluminescence. The complex was further used to image xe...