LLORENS DE LOS RÍOS MARÍA CANDELARIA
Congresos y reuniones científicas
Título:
Transferrin as a potential carrier in photodynamic therapy (PDT) and cell phototoxicity induced by cr (PHEN) 33+
Autor/es:
GARCÍA, PABLO FACUNDO; CAVALLO, NATALIA; LLORENS MARÍA CANDELARIA; PERRONE, ANA PAULA; SILVERO, J; ARGUELLO, GERARDO ; CABANILLAS, ANA MARÍA
Lugar:
Mar del Plara, Buenos Aires
Reunión:
Congreso; LVII Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2012
Institución organizadora:
Sociedad Argentina de Investigación Clínica
Resumen:
Phenantroline chromium (III) complexes have been studied as
possible photosensitizers to Photodynamic Therapy (PDT). The
photochemical and photophysical properties of these complexes
make them important compounds to be studied. It is speculated
that the Cr(III) complexes have to be carried inside the cell to
perform the effect. Our aim was to study the association of the
Transferrin (Trf) with Cr(phen)3
3+ and its potential capability of
transportation to the inner cell. We also studied the toxicity of
Cr(phen)3
3+ in its fundamental and excited state induced by LED
irradiation at 472nm. In order to assess the possible association
Trf-Cr(phen)3
3+, we used Bhatthacharrya`s equation to measure
the binding constant (Kb
) between the complex and the Trf at different pHs, from 7.40 to 5.40. We used circular dichroism (CD)
to evaluate whether the complex induced changes in secondary
and tertiary structure of HoloTrf. The results show that the Kb
for Trf-Cr(phen)3
3+, is pH dependent, being lower at more acidic
pHs (5,40-compatible with endosomal compartments), suggesting that the complex could be released inside the cell. From
CD experiments, we show that the protein, in presence of the
complex, does not suffer conformational changes, indicating
that the Trf-Receptor is able to recognize HoloTrf as well as
HoloTrf-Cr(phen)3
3+. By MTT assay, we studied changes in
MDA-MB231 (breast carcinoma) cell viability induced by different
concentrations of Cr(III) complex (with or w/o Trf). Cell Viability
diminished significantly when the complex is associated to the
Trf. It also diminished from 0.942 to 0.797 (relative values) by
10µM of complex after the cell were irradiated by a short period
of time, which first show that the excited state of the complex
induced a higher degree of cytotoxicity than the fundamental
state. The results suggest that Trf is a potential carrier of Cr
(III) complexes for PDT.