Cytotoxic effects of light-activated Merocyanine 540 products (pMC540) for PDT tumor therapy

CALZETTA, N.L.; FARINOLA, J.; MARANZANA, E.S.B.; ALONSO, S. DEL V.

Carlos Paz

Congreso; XLII Reunión Anual de la Sociedad Argentina de Biofísica; 2013

Sociedad Argentina de Biofísica

Photodynamic therapy (PDT) usually involves the administration of a photoactive compound to the subject to be treated followed by exposing the specific target location or target organ of the subject to light. The potential of various photoactive compounds as antiseptic, antibacterial, antiviral, and antitumor agents is well established. The ability of these compounds to become excited on exposure to light has been exploited in vitro and in vivo. However, simultaneous exposure of the target to the photoactive agent and to light is a prerequisite for photodynamic action, thereby limiting the application of PDT to accessible targets, e. g., localized solid tumors to which the light could easily be delivered. To overcome this limitation, the pre-activation of photoactive compounds with light prior to their use in biological targets is an alternative strategy. This process involves controlled exposure of photoactive compounds to light prior to their use, resulting in the formation of heretofore unknown photoproducts. The biological activity of pre-activated merocyanine 540 (pMC540) has bees documented. The results of these studies showed that pMC540 was citotoxic to certain tumor cell lines and enveloped viruses. The present study was carried out to obtain MC540 products and evaluate the in vitro toxicity of pMC540 and compare structure-function to MC540. We report the results of investigation conducted to study the toxicity of pMC540 in breast tumor cell line as well its half-time to evaluate if pMC540 retains its therapeutic activity subsequent to photoactivation.