Novel PDD-PDT system based on spectrophotometric real-time fluorescence monitoring and MALDI-TOF-MS analysis of tumors

Abstract

In the PDT practice for tumor patients, the dose and irradiation time for the treatment are chosen by experience and not by real need. To establish advanced PDD-PDT model system for patients, we developed a method for monitoring the cell-death based on a spectrophotometric real-time change in fluorescence in HeLa-tumors during Photofrin®-PDT and ALA-PDT. Here, we describe the results of application of the new PDD-PDT system to human tumors. The fluorescence spectra obtained from human tumors were analyzed by the differential spectral analysis. The mass-spectral changes of tumor tissues during PDD-PDT were also examined by MALDI-TOF-MS/MS. The first author's seborrheic keratosis was monitored with this system during the PDD-PDT with a topically applied ALA-ointment. The changes in fluorescence spectrum were successfully detected, and the tumor regressed completely within 5 months. The differential spectral analysis of PDD-PDT-fluorescence monitoring spectra of tumors and isolated mitochondria showed a marked decrease of three peaks in the red region indicative of the PDD (600 - 720 nm), and a transient rise followed by a decline of peaks in the green region indicative of the PDT (450 - 580 nm). The MALDI-TOF-MS analysis of PDD-PDT HeLa-tumors showed a consumption of Photofrin-deuteroporphyrin and ALA-PpIX, and decreases in protein mass in the range of 4,000 - 16,000 Da, m/z 4929, 8564, 10089, 15000, and an increase in m/z 7002 in a Photofrin® PDD-PDT monitoring tumor.