In vivo microcartography and subcellular imaging of tumor angiogenesis: a novel platform for translational angiogenesis research.
OBJECTIVE
To eliminate the variable of tumor heterogeneity from a novel in vivo model of tumor angiogenesis.


METHODS
We developed a method to navigate tumor neovasculature in a living tissue microenvironment, enabling relocation of a cell- or microregion-of-interest, for serial in vivo imaging. Orthotopic melanoma was grown, in immunocompetent Tie2GFP mice. Intravital multiphoton fluorescence and confocal reflectance imaging was performed, on a custom microscope with motorized stage and coordinate navigation software. A point within a Tie2GFP+ microvessel was selected for relocation. Custom software predicted target coordinates based upon reference points (tissue-embedded polystyrene beads) and baseline target coordinates. Mice were removed from the stage to make previously-obtained target coordinates invalid in subsequent imaging.


RESULTS
Coordinate predictions always relocated target points, in vivo, to within 10-200 microm (within a single 40x field-of-view). The model system provided a virtual living histology of tumor neovascularization and microenvironment, with subcellular spatial resolution and hemodynamic information.


CONCLUSIONS
The navigation procedure, termed in vivo microcartography, permits control of tissue heterogeneity, as a variable. Tie2 may be the best reporter gene identified, to-date, for intravital microscopy of tumor angiogenesis. This novel model system should strengthen intravital microscopy in its historical role as a vital tool in oncology, angiogenesis research, and angiotherapeutic drug development.
Sloan Kettering Institute for Cancer Research, 418 East 68th Street, New York, NY 10065, USA. dunphym@mskcc.org
Mark P S
MP
Dunphy
David
D
Entenberg
Ricardo
R
Toledo-Crow
Steven M
SM
Larson
D000818:Animals; D003952:Diagnostic Imaging / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008546:Melanoma, Experimental / Q000098:blood supply* / Q000175:diagnosis* / Q000648:ultrastructure; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D036641:Microscopy, Fluorescence, Multiphoton; D055806:Microvessels / Q000473:pathology*; D009389:Neovascularization, Pathologic; D042787:Receptor, TIE-2 / Q000378:metabolism; D015203:Reproducibility of Results
D049452:Green Fluorescent Proteins; D042787:Receptor, TIE-2