Comparative study on the ALA photodynamic effects of human glioma and meningioma cells

Background and Objective: The purpose of this study was to compare the diff erential susceptibility to photodynamic therapy (PDT) mediated damage in hu man U-105MG glioma cells and CB-157MN meningioma cells in vitro using B-ami nolevulinic acid (ALA) as photosensitizer, and to determine if growth facto rs would enhance PDT-mediated damage of these cells. Study Design/Materials and Methods: U105MG or CH-157MN cells were irradiate d 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 g rowth factor (EGF), basic fibroblast growth factor (bFGF), or platelet deri ved growth factor BE (PDGF-BB) was added to achieve a final concentration o f 50 ng/ml. 30 minutes later, cells were incubated with ALA (100 mu g/ml) f or 24 hours, washed, and irradiated with light (11 J/cm(2)). MTT tetrazoliu m 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 suscep tibility to ALA-PDT was profoundly lower for CH-157MN meningioma cells than U-105MG glioma cells. When incubated with ALA (100 mu g/ml), U-105MG cells exhibited an LD50 around 8 J/cm(2) of light irradiation, whereas that of C H-157MN cells was more than 25 J/cm(2). EGF, bFGF, or PDGF-BB did not have any effects on the susceptibility of these two cell lines to ALA-PDT. Conclusion: 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. (C) 1999 Wiley-Liss, Inc.