Delta-aminolevulinic acid cytotoxic effects on human hepatocarcinoma cell lines.
BACKGROUND
Acute Intermittent Porphyria is a genetic disorder of heme metabolism, characterized by increased levels of porphyrin precursors, delta-aminolevulinic acid (ALA) and porphobilinogen (PBG). ALA has been reported to generate reactive oxygen species and to cause oxidative damage to proteins, subcellular structures and DNA. It is known that oxidative stress can induce apoptosis. The aim of this work was to study the cytotoxic effect of ALA on two hepatocarcinoma cell lines.


RESULTS
We have determined the impact of ALA on HEP G2 and HEP 3B hepatocarcinoma cell lines survival as measured by the MTT assay. ALA proved to be cytotoxic in both cell lines however; HEP G2 was more sensitive to ALA than HEP 3B. Addition of hemin or glucose diminished ALA cytotoxicity in HEP G2 cells; instead it was enhanced in HEP 3B cells. Because apoptosis is usually associated with DNA fragmentation, the DNA of ALA treated and untreated cells were analyzed. The characteristic pattern of DNA fragmentation ladders was observed in ALA treated cells. To elucidate the mechanisms of ALA induced apoptosis, we examined its effect on p53 expression. No changes in p53 mRNA levels were observed after exposure of both cell lines to ALA for 24 h. CDK2 and CDK4 protein levels were reduced after ALA treatment at physiological concentrations.
De Siervi
Adriana
A
Centro de Investigaciones sobre Porfirinas y Porfirias, Argentine National Research Council (CONICET), Department of Biological Chemistry, FCEN, University of Buenos Aires, Argentina. desiervi@qb.fcen.uba.ar
Vazquez
Elba S
ES
Rezaval
Carolina
C
Rossetti
María V
MV
del Batlle
Alcira M
AM
D000622:Aminolevulinic Acid / Q000627:therapeutic use / Q000633:toxicity*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004273:DNA, Neoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology; D006427:Hemin / Q000494:pharmacology; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000378:metabolism
D004273:DNA, Neoplasm; D013778:Tetrazolium Salts; D013844:Thiazoles; D016159:Tumor Suppressor Protein p53; D006427:Hemin; D000622:Aminolevulinic Acid; C022616:thiazolyl blue; D005947:Glucose