Cellular localization of Visudyne as a function of time after local injection in an in vivo model of squamous cell carcinoma: an investigation into tumor cell death.
OBJECTIVE
To evaluate the effects of time on cellular localization of Visudyne after local injection.


METHODS
Twenty athymic nude mice.


METHODS
A squamous cell carcinoma (SCC) cell line (A-431) was injected into right and left dorsolumbar subcutaneous tissue of each mouse, representing treatment (T) and control (C) tumors. In experiment 1 (Exp 1; n = 10) and 2 (Exp 2; n = 10), the T tumors received a local injection of Visudyne (0.1 mg/cm(3)), and C tumors received an equal dose of 5% dextrose in water (D5W). Mice were randomly subdivided into two groups (A and B; n = 5 per group). Mice in Exp 1A and B were sacrificed 1 and 30 min after local injection, respectively. Experiment 1A and B tumors were evaluated by fluorescence microscopy to determine drug localization. Experiment 2A and B tumors were exposed to LED illumination 1 and 30 min after injection, respectively, and evaluated by transmission electron microscopy (TEM) to determine ultrastructural tumor cell damage.


RESULTS
Fluorescence was detected within the cytoplasm of T tumors in both Exp 1A and B. Significance was detected in fluorescence intensity between T1 min vs. T30 min (P = 0.03) and between T1 min and C1 min tumors (P = 0.01), respectively. Tumors in Exp 2A and B demonstrated evidence of apoptotic cell death.


CONCLUSIONS
Fluorescence microscopy demonstrated higher Visudyne concentration within SCC cytoplasm of 1 min compared with 30-min tumors. Transmission electron microscopy results revealed that tumors treated by photodynamic therapy (PDT) within 30 min of local injection undergo cellular apoptosis.
Barnes
Laura D
LD
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, 900 East Campus Drive, Columbia, MO 65211, USA.
Giuliano
Elizabeth A
EA
Ota
Juri
J
D000818:Animals; D001692:Biological Transport; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects*; D045744:Cell Line, Tumor; D006801:Humans; D053685:Laser Therapy; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000188:drug therapy; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011166:Porphyrins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000077362:Verteporfin
D017319:Photosensitizing Agents; D011166:Porphyrins; D000077362:Verteporfin