Transferrin as a potential carrier in Photodynamic Therapy (PDT) and cell phototoxicity induced by Cr(phen)33+

PABLO F. GARCÍA; NATALIA CARBALLO; CANDELARIA LLORENS; ANA PERRONE; JAZMÍN SILVERO; ARGÜELLO, GERARDO ANÍBAL; ANA M. CABANILLAS

Mar del Plata

Congreso; LVII Reunión anual de la Sociedad Argentina de Investigación Clínica; 2012

Sociedad Argentina de Investigación Clínica

Phenantroline chromium (III) complexes have been studied as possible photosensitizers to . The photochemical and photophysical properties of these complexes make them important compounds to be studied. It is speculated that the have to be carried inside the cell to perform the effect. Our aim was to study the association of the (Trf) with Cr(phen)33+ and its potential capability of transportation to the inner cell. We also studied the toxicity of Cr(phen)33+ in its fundamental and excited state induced by LED irradiation at 472nm. In order to assess the possible association Trf-Cr(phen)33+, 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)33+, 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)33+. 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.