Enhanced susceptibility of mouse squamous cell carcinoma to photodynamic therapy combined with low-dose administration of cisplatin.
OBJECTIVE
We have investigated the antitumor effect of photodynamic therapy (PDT), using Photofrin as the photosensitizer, combined with low-dose cisplatin (CDDP) on NR-S1 mouse squamous cell carcinoma.


METHODS
CDDP (5 mg/kg body weight) was injected intraperitoneally either 1 hour or 3 hours prior to PDT or immediately afterward. Twenty-four hours after each protocol, the antitumor effects were evaluated by percentage area of the tumor necrosis in hematoxylin-eosin stained specimens as well as terminal deoxynucleotidyl transferase-mediated d-UTP nick-end labeling indices. Furthermore, the tumor sizes were evaluated at 3, 7, and 10 days after each protocol.


RESULTS
The antitumor effect of PDT was enhanced by administration of CDDP 3 hours before PDT, whereas the administration of CDDP 1 hour before PDT or immediately after PDT did not potentiate a PDT antitumor effect.


CONCLUSIONS
Administration of low-dose CDDP 3 hours before PDT appears to be a useful treatment modality.
Uehara
Masataka
M
Division of Oral and Maxillofacial Surgical Reconstruction and Restoration, Department of Developmental and Reconstructive Medicine, Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto, Nagasaki, Japan. uehara@net.nagasaki-u.ac.jp
Inokuchi
Tsugio
T
Ikeda
Hisazumi
H
D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology* / Q000532:radiotherapy; D002945:Cisplatin / Q000008:administration & dosage*; D017323:Dihematoporphyrin Ether / Q000008:administration & dosage*; D020287:In Situ Nick-End Labeling; D028022:Low-Level Light Therapy; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D009336:Necrosis; D009372:Neoplasms, Connective Tissue / Q000188:drug therapy / Q000532:radiotherapy; D010778:Photochemotherapy / Q000379:methods*; D011838:Radiation-Sensitizing Agents / Q000008:administration & dosage*; D018714:Radiotherapy, Adjuvant; D018709:Statistics, Nonparametric; D040521:Subcutaneous Tissue / Q000473:pathology; D016896:Treatment Outcome; D047368:Tumor Burden / Q000187:drug effects
D000970:Antineoplastic Agents; D011838:Radiation-Sensitizing Agents; D017323:Dihematoporphyrin Ether; D002945:Cisplatin