Ferrochelatase, a novel target for photodynamic therapy of cancer.
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Protoporphyrin IX
Ferrochelatase
The quantification of the induced fluorescence in tumor tissue is important to design optical equipment for photodynamic diagnosis (PDD). The fluorescence intensities of Protoporphyrin IX (PpIX) solved in Dimethylsulfoxid and induced via application of Aminolevulinic Acid in cells, cultivated in the hen's eggs model, have been measured photometrically. With an optimized CCD-camera-systems fluorescent tumor areas were detected before and after photodynamic therapy (PDT). The ratio of dead cells was detected by staining with trypan blue after PDT. The measurements were carried out with various energy densities at the time of maximal PpIX-enrichement.
Protoporphyrin IX
Trypan blue
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Recently we published the article ‘Accumulation of protoporphyrin IX in medulloblastoma cell lines and sensitivity to subsequent photodynamic treatment’. In this commentary, we review protoporphyrin IX accumulation after application of 5-aminolaevulinic acid and the resulting sensitivity of medulloblastoma cells to photodynamic therapy.
Protoporphyrin IX
Phototoxicity
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Ferrochelatase
Protoporphyrin IX
Porphobilinogen deaminase
Erythropoietic protoporphyria
3T3 cells
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Bovine skin fibroblasts accumulated protoporphyrin IX when incubated in culture with the porphyrin-heme precursor, delta-aminolevulinic acid (ALA). Fibroblasts from cattle homozygous for erythropoietic protoporphyria (EPP) and with the clinical symptoms of the disease accumulated approximately sixfold greater amounts of protoporphyrin IX than cells from normal control animals. Cells from obligatory heterozygous animals, which are clinically normal, accumulated an intermediate level of protoporphyrin IX. When these cells were incubated with ALA and CaMg EDTA, all types of cells accumulated approximately the same amount of protoporphyrin IX (approximately 500 nmol/mg protein), suggesting that ferrochelatase activity was equally low after inhibition by treatment with CaMg EDTA in all cells. Thus the ratio of protoporphyrin IX accumulation from ALA in cultures treated with CaMg EDTA compared with controls treated with ALA alone was greatest in normal cells, least in EPP cells, and intermediate in the heterozygote cells. These findings suggest that the amount of protoporphyrin IX accumulation from ALA reflects the extent of deficiency of ferrochelatase and is proportional to the dosage of abnormal EPP gene in cultured fibroblasts. Similarly, stimulation of porphyrin accumulation by CaMg EDTA reflects diminished ferrochelatase activity in these cells. Thus, the results of this study demonstrate the usefulness of estimating protoporphyrin IX formation from ALA for the detection of an EPP gene defect in cultured bovine skin fibroblasts.
Ferrochelatase
Erythropoietic protoporphyria
Protoporphyrin IX
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Ferrochelatase
Protoporphyrin IX
Tetrapyrrole
Hemin
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Ferrochelatase (FECH), the enzyme at the last step of the heme-biosynthetic pathway, is involved in the formation of Zn-protoporphyrin via an iron-removal reaction of heme. To improve the efficacy of the formation of Zn-protoporphyrin from heme, the use of recombinant FECHs from porcine, yeast, and bacteria was examined. Incubation of FECH with myoglobin in the presence of ascorbic acid and cysteine resulted in the efficient conversion of myoglobin-heme to Zn-protoporphyrin. Exogenously added recombinant yeast FECH facilitates the production of Zn-protoporphyrin from myoglobin-heme and heme in meat, via the replacement of iron in the protoporphyrin ring by zinc ions. A large amount of Zn-protoporphyrin was also generated by the catalysis of FECH using an intact piece of meat as a substrate. These findings can open up possible approaches for the generation of a nontoxic bright pigment, Zn-protoporphyrin, to shorten the incubation time required to produce dry-cured ham.
Ferrochelatase
Protoporphyrin IX
Hemin
Hemeprotein
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The quantification of the fluorescence is important to design optical equipment for Photodynamic Diagnosis. The fluorescence intensity of Protoporphyrin IX in solution and induced in cells, cultivated in the hen's eggs model, have been measured photometrically. With an optimized CCD-camera-systems fluorescent tumor areas were detected before and after PDT. The ratio of dead cells was detected by staining with trypan blue after PDT. The measurements were carried out various energy densities at the time of maximal PpIX-enrichement.
Protoporphyrin IX
Trypan blue
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Protoporphyrin IX
Organelle
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Ferrochelatase
Protoporphyrin IX
Abcg2
Efflux
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Protoporphyrin IX
Organelle
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