RIBOFLAVINS INDUCE DIFFERENT PATTERNS OF CELL DEATH IN SQUAMOUS CARCINOMA CELLS

JUAREZ A V; BOETTO N; PITTAU R; HAGGI E; TORRES A; PONS P

BIOCELL

INST HISTOL EMBRIOL-CONICET

Lugar: Mendoza; Año: 2011 vol. 35 p. 22 - 22

0327-9545

Photodynamic Therapy (PDT) is a treatment based on cell death induced by light activation of a Photosensitizer (P) localized in tumor cells. Riboflavin (RF) is an efficient P and could be applied for PDT. Our aim was to evaluate the effect of light-activated RF and RF Ester (RFE) on the human squamous carcinoma cell line SCC13. Cells were cultured in DMEM, incubated with RFL or RFH (50, 100uM) and irradiated with 24-high power LED lamp of 444nm. After that, cells were left in darkness for 6 or 24h. Cell viability was determined by neutral red assay and cell proliferation by Ki-67 immunocytochemistry. Apoptosis was evaluated in situ by uptake of Hoechst33342. Morphological studies were performed by high resolution optical microscopy and electron microscopy. Statistics: ANOVA-Tukey. After irradiation, both types of RF induced cell death, with decreased proliferation rate (p less than 0,05). Treated cells showed apoptotic nuclei by nuclear fluorescence staining. Moreover, some cells exhibited chromatin condensation and several apoptotic bodies; while other cells presented typical ultrastructural morphology of necrosis. We also observed a third type of cell response characterized by cytoplasmic vacuolization and surface blebs without chromatin condensation. These finding were more notorious al 24h after light irradiation. These results demonstrate that both FS could be effective in the application of PDT in superficial skin tumors.