Photodynamically induced effects in colon carcinoma cells (WiDr) by endogenous photosensitizers generated by incubation with 5-aminolaevulinic acid.

Abstract

Human adenocarcinoma cells of the line WiDr have been treated with 2 mM 5-aminolaevulinic acid (5-ALA) in the presence of 10% foetal calf serum. The treatment induces a linear accumulation of protoporphyrin IX (PpIX) for at least 7.5 h. After 7.5 h of incubation about 45% of the PpIX accumulated is cell-bound, while the rest is found in the medium (25%) or lost from the cells during washing with phosphate-buffered saline (30%). Exposure to white light at an intensity of 30 W/m2 for 18 min results in 95% reduction of clonogenicity in cells treated with 2 mM 5-ALA for 3.5 h. The enzymatic activities of enzymes located in cytosol (glyceraldehyde 3-phosphate dehydrogenase and lactate dehydrogenase) and lysosomes (acid phosphatase and beta-glucuronidase) are not influenced by a 5-ALA and light treatment inactivating about 35% of the cells. The MTT assay, which reflects mitochondrial dehydrogenase activity, but not succinate dehydrogenase, is partly inhibited by the same treatment. Treatment with 5-ALA in the absence of light increases O2 consumption by a factor of two, while the O2 consumption is inhibited when 5-ALA treatment is combined with exposure to light. In addition, 5-ALA and light exposure enhance accumulation of rhodamine 123 by 40% and reduce the intracellular ATP level by 25%. Confocal laser scanning microscopical analysis indicates granular perinuclear localization of the PpIX formed by 5-ALA treatment. In conclusion, photodynamic treatment using 5-ALA as a prodrug induces damage to mitochondrial function without inhibiting lysosomal and cytosolic marker enzymes.

• Authors: O A Gederaas, M H Rasch, K Berg, J W Lagerberg, T M Dubbelman
• Journal: Journal of photochemistry and photobiology. B, Biology (J Photochem Photobiol B) Vol. 49 Issue 2-3 Pg. 162-70 (Apr 1999) ISSN: 1011-1344 [Print] Switzerland
• PMID: 10392465 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor
• Fluorescent Dyes
• Heptanoates
• Photosensitizing Agents
• Protoporphyrins
• Rhodamine 123
• succinylacetone
• Aminolevulinic Acid
• Adenosine Triphosphate
• protoporphyrin IX

Topics

• Adenosine Triphosphate (metabolism)
• Aminolevulinic Acid (therapeutic use)
• Biomarkers, Tumor
• Colonic Neoplasms (drug therapy)
• Fluorescent Dyes (pharmacokinetics)
• Heptanoates (pharmacology)
• Humans
• Microscopy, Confocal
• Microscopy, Fluorescence
• Oxygen Consumption (drug effects)
• Photochemotherapy
• Photosensitizing Agents (therapeutic use)
• Protoporphyrins (metabolism)
• Rhodamine 123 (pharmacokinetics)
• Time Factors
• Tumor Cells, Cultured