title: Comparative study on the ALA photodynamic effects of human glioma and meningioma cells.
abstract: OBJECTIVE
  The purpose of this study was to compare the differential susceptibility to photodynamic therapy (PDT) mediated damage in human U-105MG glioma cells and CH-157MN meningioma cells in vitro using 5-amino-levulinic acid (ALA) as photosensitizer, and to determine if growth factors would enhance PDT-mediated damage of these cells.
  
  
  METHODS
  U-105MG or CH-157MN cells were irradiated with polychromatic light in the presence of ALA. A Xenon lamp (150 W) was used as the light source. For the study on the effect of growth factor on ALA-PDT, cells were cultured in serum free medium for 24 hours. Epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), or platelet derived growth factor BB (PDGF-BB) was added to achieve a final concentration of 50 ng/ml. 30 minutes later, cells were incubated with ALA (100 microg/ml) for 24 hours, washed, and irradiated with light (11 J/cm2). MTT tetrazolium assays were performed 24 hours after light irradiation.
  
  
  RESULTS
  The inhibition of metabolic cellular function in U-105MG cells by ALA depended on both light energy density and ALA concentration. The susceptibility to ALA-PDT was profoundly lower for CH-157MN meningioma cells than U-105MG glioma cells. When incubated with ALA (100 microg/ml), U-105MG cells exhibited an LD50 around 8 J/cm2 of light irradiation, whereas that of CH-157MN cells was more than 25 J/cm2. EGF, bFGF, or PDGF-BB did not have any effects on the susceptibility of these two cell lines to ALA-PDT.
  
  
  CONCLUSIONS
  ALA-PDT was more effective in killing U-105MG glioma cells than CH-157MN meningioma cells. The differential susceptibility was likely due to differential accumulation of PpIX in these cells. EGF, bFGF, or PDGF-BB did not have stimulatory or inhibitory effect on the efficiency of ALA-PDT.
mesh_terms: D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D000704:Analysis of Variance; D004307:Dose-Response Relationship, Radiation; D004815:Epidermal Growth Factor / Q000378:metabolism; D005910:Glioma / Q000378:metabolism / Q000628:therapy*; D006801:Humans; D008577:Meningeal Neoplasms / Q000378:metabolism / Q000628:therapy*; D008579:Meningioma / Q000378:metabolism / Q000628:therapy*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured / Q000528:radiation effects