Two course illuminating scheme improves aminolevulinic acid photodynamic therapy in cell cultures

Cell Mol Biol (Noisy-le-grand). 2002 Dec;48(8):903-9.


Photodynamic therapy with the pro-drug 5-aminolaevulinic acid (ALA-PDT) is being used for the treatment of Barrett's oesophagus. We postulated that a first early course of ALA-PDT would increase protoporphyrin IX (PPIX) accumulation and thus the efficacy of a second course of ALA-PDT, by manipulating ferrochelatase (FC) and porphobilinogen deaminase (PBG-d) activity. Human EBV-transformed lymphoblastoid cells were used as a model of human tumour cells for the ability to form haem is present in all cells. After a single course of illumination (633 nm, 100 mW/cm2) the FC activity decreased significantly whereas the PBG-d activity did not change. During continued incubation with ALA following the first illumination, cells accumulated up to four times more PPIX than non-illuminated controls [220% +/- 30% versus (vs) 55% +/- 5%; p<0.001]. Two illuminations resulted in more cell death than one illumination (97% +/- 1% vs 80% +/- 2%; p<0.001). Since a second course of ALA-PDT within 3 hr after the first course resulted in a four fold increase in PPIX accumulation and significantly more cell death, we propose that a two course ALA-PDT scheme might improve the efficacy of this treatment for Barrett's oesophagus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminolevulinic Acid / therapeutic use*
  • Barrett Esophagus / therapy
  • Cell Line, Transformed
  • Cells, Cultured
  • Ferrochelatase / biosynthesis
  • Humans
  • Hydroxymethylbilane Synthase / biosynthesis
  • Light
  • Photochemotherapy / methods*
  • Porphyrins / metabolism
  • Protoporphyrins / biosynthesis
  • Time Factors


  • Porphyrins
  • Protoporphyrins
  • Aminolevulinic Acid
  • protoporphyrin IX
  • Hydroxymethylbilane Synthase
  • Ferrochelatase