Specific labeling of microtumors in the Hen's Egg Test system by dimethoxyhematoporphyrin

The accumulation of fluorescent dyes and anticancer drugs in tumors is a fundamental requirement for tumor-diagnosis and -therapy. We tested various photosensitizers on vascularized microtumors in the Hen's Egg Test system according to their distribution and accumulation by in-situ videofluorescence microscopy and their influence on tumor blood flow by Laser-Doppler spectroscopy. Only 2,4-di(alpha-methoxyethyl)-hematoporphyrin showed strict tumor localization while diglucosamidyl-heptyl-chlorin labeled cell membranes exclusively. Results from Laser-Doppler spectroscopy did not show any influence on tumor blood flow. Intelligent combining of the properties of these sensitizers with accumulation strategies should show in principle strict tumor localization without targeting of non-tumor tissues.