DIFFERENT MODES OF CELL DEATH INDUCED BY ZnPcOCH3-BASED PHOTODYNAMIC THERAPY IN LARYNGES CARCINOMA HUMAN CELL LINE HEP-2

YSLAS EI, PRUCCA C, DURANTINI EN, RIVAROLA V.

VILLA GIARDINO - CÓRDOBA

Congreso; Cordoba Society for Biology; 2005

Sociedad de Biología de Córdoba

Photodynamic therapy (PDT) is a promising new treatment formalignant and non-malignant diseases. The procedure requires exposureof cell to a photosensitizing drug followed by irradiationwith visible light of the appropriate wavelength in presence ofmolecular oxygen. The primary role of PDT is to kill unwantedphotodynamic cell by two mechanisms apoptosis and necrosis.This work describes the photophysical properties, accumulation,localization and the modes of cell death of tetra methoxy Zn IIphthalocyanine on Hep-2. The first analysis showed that cell survival(MTT assay) was no affected in light alone. Both incubationtime 6h and 18h with different concentrations 0.1μM and 0.5μMdid no induce dark toxicity. On the contrary, when Hep-2 cells wereincubated with ZnPcOCH3 and post-irradiated with different lightdose it was found an efficiency cell photokilling in drug concentration,irradiation time and post-PDT time dependent manner. Onthe other hand, we observed that the most of sere cells presentmorphology apoptotic 24 h post-PDT using 0.5μM of ZnPcOCH3and 5 min irradiation. The immunocytochemistry biotin-avidin–peroxidase (ABC) method confirmed expression of caspase 3. Onthe contrary, 15 min irradiation and 24h post-PDT produced necrosiscell (Hoechst-33258, Toluidine blue and DNA fragmentation).Hep-2 cultures incubated with ZnPcOCH3 exhibited a perinuclearfluorescence suggesting that ZnPcOCH3 localizes inlysosome. Due to that in vitro model ZnPcOCH3 showed a highphotosensitizing efficiency, we further investigate its behaviour invivo model.