Photosensitization of colorectal carcinoma model systems mediated by the xanthene rose bengal

Abstract

Colorectal cancer is currently the third with the highest incidence and the second in the ranking of deaths in the world. Traditional treatments such as chemotherapy and radiotherapy cause severe side effects, demanding new therapeutic strategies. In this context, photodynamic therapy (PDT) stands out owing to its effectiveness in reducing tumor cell viability. Herein, we shall evaluate the photodynamic efficiency of the Rose Bengal (RB) photosensitizer (FS) in the in vitro culture of cells derived from colorectal carcinoma (Caco-2). Cell membrane models based on Langmuir and Langmuir-Schaefer (LS) films will be used to unravel the interaction mechanisms and the effects of the photoinduced lipid oxidation responsible for cell toxicity. Langmuir films will be produced from the lipid extract of Caco-2 cells and characterized by surface pressure vs. area (À-A isotherms) in subphase containing different concentrations of RB. Characterization of LS films by Fourier transform infrared spectroscopy (FTIR) will provide information on the RB binding mechanisms. The photochemical reactions will be triggered by illuminating the Langmuir monolayers at 30 mN/m, evaluated through the evolution of surface area. At the end of the project, we aim not only to obtain knowledge about the photodynamic efficiency of RB in in vitro culture of Caco-2 cells, but also to unravel the mechanisms underlying the triggered photochemical reactions. This master's project is linked to the Thematic Project n° 2018/22214-6.