Novel receptor-targeted fluorescent contrast agents for in vivo tumor imaging.
OBJECTIVE
To evaluate the efficacy of a novel tumor receptor-specific small-peptide-near-infrared dye conjugate for tumor detection by optical imaging.


METHODS
A novel, near-infrared dye-peptide conjugate was synthesized and evaluated for tumor-targeting efficacy in a well-characterized rat tumor model (CA20948) known to express receptors for the chosen peptide. A simple continuous-wave optical imaging system, consisting of a near-infrared laser diode, a cooled CCD camera, and an interference filter, was used in this study.


RESULTS
Tumor retention of two non-tumor-specific dyes, indocyanine green and its derivatized analogue, bis-propanoic acid cyanine dye (cypate), was negligible. In contrast, the receptor-specific peptide-cypate conjugate (cytate) was retained in the CA20948 tumor, with an excellent tumor-tonormal-tissue ratio in the six rats examined.


CONCLUSIONS
Optical detection of tumors with a receptor-targeted fluorescent contrast agent has been demonstrated. This result represents a new direction in cancer diagnosis and patient management.
Achilefu
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S
Discovery Research, Mallinckrodt Inc., St. Louis, Missouri 63042, USA. Samuel.achilefu@mkg.com
Dorshow
R B
RB
Bugaj
J E
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Rajagopalan
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D000818:Animals; D003287:Contrast Media; D003952:Diagnostic Imaging; D005453:Fluorescence; D005456:Fluorescent Dyes; D007208:Indocyanine Green / Q000031:analogs & derivatives; D007834:Lasers; D008297:Male; D009374:Neoplasms, Experimental / Q000175:diagnosis*; D055095:Optics and Photonics; D010190:Pancreatic Neoplasms / Q000175:diagnosis; D010455:Peptides; D011471:Prostatic Neoplasms / Q000175:diagnosis; D051381:Rats
D003287:Contrast Media; D005456:Fluorescent Dyes; D010455:Peptides; D007208:Indocyanine Green