5-Aminolevulinic Acid-Mediated Photodynamic Therapy on Hep-2 and MCF-7c3 Cells.

M. G. ÁLVAREZ, M. S. LACELLI, V. RIVAROLA, A. BATLLE, H. FUKUDA

JOURNAL OF ENVIRONMENTAL PATHOLOGY, TOXICOLOGY AND ONCOLOGY : OFFICIAL ORGAN OF THE INTERNATIONAL SOCIETY FOR ENVIRONMENTAL TOXICOLOGY AND CANCER.

Begell House

Año: 2007 p. 75 - 82

0731-8898

The cytotoxic effect of 5-aminolevulinic acid (ALA) induced protoporphyrin IX (PPIX) on two human carcinome cell lines, MCF-7c3 and Hep2 cells, was studied. In both cell lines, PPIX content depends on the ALA concentration and incubation time. The maximal PPIX content was higher in the MCF-7c3 cells reaching a value of 8 mg/106 cells, compared to the Hep-2 cells, which accumulated 3.2 mg/106 cells. Treatment of cells with the iron chelator desferrioxamine prior to  ALA exposure enhances  the amount of PPIX, consequently diminishing enzymatic activity  of ferroquelatase.  Photosensitization of the cells was in acorrelation with the PPIX content, therefore, conditions leading to an 80%  cell death in the MCF-7c3 cells provokes a 50 % cell death in the Hep 2 cells. Using fluorescense microscopy,  cell morphology was analized  after incubation with 1 mM ALA during 5 hr and irradiation with 54 J cm -2, 24 hr post-PDT, MCF-7c3 cells revealed the typical morphological changes of necrosis. Under the same condition, Hep-2 cells produced chromatine fragmentation characteristic of apoptosis. PPIX accumulation was observed to occur in a perinuclear region in the MCF-7c3 cells; while in Hep-2 cells, it was localized in lysosome. Different mechanisms of cell death were observed in both cell lines, depending on the different intracellular localization of PPIX.