Tumor endothelial marker imaging in melanomas using dual-tracer fluorescence molecular imaging.
OBJECTIVE
Cancer-specific endothelial markers available for intravascular binding are promising targets for new molecular therapies. In this study, a molecular imaging approach of quantifying endothelial marker concentrations (EMCI) is developed and tested in highly light-absorbing melanomas. The approach involves injection of targeted imaging tracer in conjunction with an untargeted tracer, which is used to account for nonspecific uptake and tissue optical property effects on measured targeted tracer concentrations.


METHODS
Theoretical simulations and a mouse melanoma model experiment were used to test out the EMCI approach. The tracers used in the melanoma experiments were fluorescently labeled anti-Plvap/PV1 antibody (plasmalemma vesicle associated protein Plvap/PV1 is a transmembrane protein marker exposed on the luminal surface of endothelial cells in tumor vasculature) and a fluorescent isotype control antibody, the uptakes of which were measured on a planar fluorescence imaging system.


RESULTS
The EMCI model was found to be robust to experimental noise under reversible and irreversible binding conditions and was capable of predicting expected overexpression of PV1 in melanomas compared to healthy skin despite a 5-time higher measured fluorescence in healthy skin compared to melanoma: attributable to substantial light attenuation from melanin in the tumors.


CONCLUSIONS
This study demonstrates the potential of EMCI to quantify endothelial marker concentrations in vivo, an accomplishment that is currently unavailable through any other methods, either in vivo or ex vivo.
Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA, tichauer@iit.edu.
Kenneth M
KM
Tichauer
Sophie J
SJ
Deharvengt
Kimberley S
KS
Samkoe
Jason R
JR
Gunn
Marcus W
MW
Bosenberg
Mary-Jo
MJ
Turk
Tayyaba
T
Hasan
Radu V
RV
Stan
Brian W
BW
Pogue
D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000378:metabolism* / Q000493:pharmacokinetics; D008545:Melanoma / Q000378:metabolism*; D051379:Mice
D014408:Biomarkers, Tumor; D005456:Fluorescent Dyes