Red bioluminescent protein detects tumors in live animals

摘要

To aid in the fight against cancer, researchers have manufactured monoclonal antibodies that recognize antigens expressed on malignant cells, which can reveal minute and otherwise uni-rndentifiable tumors. Visualization of these malignancies, however, typically relies on expensive and toxic radioiso-tope imaging. Chun Wu et al. developed a method to detect the spread of cancer in live animals that relies on biolumi-nescence resonance energy transfer, which is safer and less costly than radioisotopernimaging. The authors created a red bioluminescent protein by conjugating a far-red fluorescent, indocyanine-derivative dye to the luciferase enzyme from the sea firefly, Cypridina. Except for the color red, most bioluminescence spectra occur in the visible range where they overlap with the absorption spectrum of hemoglobin, attenuating bioluminescence intensity. The authors attached the red bioluminescent molecule to an antibody against human delta-like protein, which is an embryonic antigen expressed on the surface of many cancer cells. In the presence of luciferin, energy transfer in the bioluminescent protein produced a fluorescence that identified hepatoma tumors in live mice. With the commercial availability of anticancer antibodies, this work may aid in the early detection of many types of malignancies, according to the authors.