Repetitive 5-aminolevulinic acid-mediated photodynamic therapy on human glioma spheroids.
The response of human glioma spheroids to repetitive 5-aminolevulinic acid-mediated photodynamic therapy (PDT) was investigated. In all cases, light fluences were kept below toxic thresholds to simulate conditions typically found at 1-2 cm depths in brain adjacent to tumor. Significant inhibition of spheroid growth was observed following multiple PDT treatments at sub-threshold light fluences. The effect appears to be insensitive to the treatment intervals investigated (weekly or bi-monthly). In all cases, suppression of growth was observed for the duration of treatment. Low fluence rates (< or = 5 mW cm(-2)) appear to be more effective than high fluence rates (25 mW cm(-2)). No evidence of PDT resistance was found in this investigation.
Madsen
Steen J
SJ
Department of Health Physics, Las Vegas Cancer Institute, University of Nevada, Las Vegas, NV 89154-3037, USA. steenm@ccmail.nevada.edu
Sun
Chung-Ho
CH
Tromberg
Bruce J
BJ
Hirschberg
Henry
H
D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D003131:Combined Modality Therapy; D005909:Glioblastoma / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000628:therapy; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D018874:Spheroids, Cellular / Q000187:drug effects* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid