Repetitive 5-aminolevulinic acid-mediated photodynamic therapy on human glioma spheroids

J Neurooncol. 2003 May;62(3):243-50. doi: 10.1023/a:1023362011705.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aminolevulinic Acid / therapeutic use*
  • Brain Neoplasms / drug therapy*
  • Brain Neoplasms / metabolism
  • Combined Modality Therapy
  • Glioblastoma / drug therapy*
  • Glioblastoma / metabolism
  • Humans
  • Microscopy, Fluorescence
  • Neoplasm Recurrence, Local / metabolism
  • Neoplasm Recurrence, Local / therapy
  • Photochemotherapy*
  • Photosensitizing Agents / therapeutic use*
  • Spheroids, Cellular / drug effects*
  • Spheroids, Cellular / metabolism
  • Tumor Cells, Cultured


  • Photosensitizing Agents
  • Aminolevulinic Acid