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Enhanced cell death in NR‐S1 tumor by photodynamic therapy: Possible involvement of Fas and Fas ligand system
Author(s) -
Yokota Tomohisa,
Ikeda Hisazumi,
Inokuchi Tsugio,
Sano Kazuo,
Koji Takehiko
Publication year - 2000
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/1096-9101(2000)26:5<449::aid-lsm4>3.0.co;2-a
Subject(s) - tunel assay , fas ligand , apoptosis , terminal deoxynucleotidyl transferase , photodynamic therapy , programmed cell death , immunohistochemistry , pathology , cancer research , biology , chemistry , medicine , microbiology and biotechnology , biochemistry , organic chemistry
Background and Objectives To investigate the effect of photodynamic therapy (PDT) on cell death in malignant tumor tissue, the frequency of terminal deoxynucleotidyl transferase‐mediated dUTP nick end‐labeling (TUNEL)‐positive cells and the possible involvement of Fas and Fas ligand system were evaluated. Study Design/Materials and Methods NR‐S1 tumor‐bearing C3H/HeNCrj mice were treated by PDT with Photofrin® (12 mg/kg body weight) and Nd:YAG dye laser (630 nm, 10 Hz, 150 J/cm 2 ). Paraffin‐embedded tissue sections from the excised tumor tissues at 6, 12, 24, 48 hours after PDT were analyzed by TUNEL for the occurrence of apoptosis and by immunohistochemistry for Fas and Fas ligand (FasL) expression. TUNEL‐positive cells as well as Fas‐ or FasL‐positive cells were counted and expressed as a percentage of positive cells per total cells. Results Based on the percent area of tumor necrotic foci, the most effective conditions for PDT were first determined. Under these conditions, PDT increased the number of TUNEL‐positive tumor cells at 12 hours after irradiation. In parallel with the increase in TUNEL‐positive cells, Fas‐positive tumor cells were also found in the same area where many TUNEL‐positive tumor cells were found. The expression of Fas ligand was found in the tumor cells surrounding TUNEL‐positive cells on serial sections. A significant increase in FasL‐positive lymphocytes was observed at 12 hours, whereas the infiltration of such lymphocytes into the area where TUNEL‐positive tumor cells were observed was rare. Conclusion The possible role of Fas/FasL system in the cell death induced by PDT with Photofrin® and Nd:YAG dye laser was suggested. Moreover, the role of infiltrated lymphocytes seemed not to be so much in this model. Lasers Surg. Med. 26:449–460, 2000. © 2000 Wiley‐Liss, Inc.