Congreso Americano 2013-4

Synergistic cytotoxicity of Temozolomide and ABT-888 in dual-drug targeted Polymeric Nanoparticles

AUTHORS/INSTITUTIONS: J. Munoz-Gamez, L. Sanjuan, R. Quiles, J. Lopez-Viota, J. León, A. Carazo, J. Casado, E. Pavón-Castillero, A. Martín, Unidad de Apoyo a la Investigación, Hospital Universitario San Cecilio, Granada, Granada, SPAIN; R. Quiles, J. León, A. Ruiz-Extremera, J. Salmeron, Centro de Investigación Biomedica en Red de Enfermedades Hepáticas y Digestivas, CIBERehd, Granada, Granada, SPAIN; L. Sanjuan, A. Martín, J. Salmeron, Departamento de Medicina, Universidad de Granada, Granada, Granada, SPAIN; A. Barrientos, Unidad Clínica de Aparato Digestivo, Hospital Universitario San Cecilio, Granada, Granada, SPAIN; A. Ruiz-Extremera, Unidad de Pediatría, Hospital Universitario San Cecilio, Granada, Granada, SPAIN

ABSTRACT: Background and aims: Hepatocellular carcinoma (HCC) is the third most common cause of death from cancer worldwide and its incidence has been increasing in recent years. Because current therapies are rarely able to achieve complete tumor ablation, it is necessary to study any new therapeutic strategy that arises. Accordingly, we propose a new and interesting strategy for HCC treatment, namely the use of poly (ADP-ribose) polymerase (PARP-1) inhibitors (ABT-888) together with temozolomide (TMZ, a DNA-damaging agent) incorporated into magnetic nanoparticles (MNPs).

Method: Magnetic Fe/Fe3O4 cores were synthetized using thermal decomposition methods, and a final layer of silica was incorporated to coat the composite MNPs. The simultaneous adsorption of TMZ and ABT888 PARP-1 inhibitor was monitored by electrophoretic mobility measurements. In vitro tests were performed with HepG2, Hep3B and PLC-PRF-5 tumoral cell lines and with WRL-68 non-tumoral cells.

Results: The MNPs were loaded simultaneously with TMZ and different concentrations of ABT888, had a final size of 16 ± 4 nm. A high degree of stability in culture medium was achieved and 50% of both drugs had been released about 10-15 hours after their dissolution in the culture medium. Laser confocal microscopy images showed that the MNPs had entered the liver tumor cells and that both drugs were released into the cells. The DNA damage induced by TMZ triggered PARP-1 activation, but this stimulus was reduced in the presence of ABT-888 coated NPs, inducing the following effects: G2/M cell cycle arrest (67% for MNPs/TMZ/ABT-888 vs. 24% in the control group, P>0.05), accumulation of DNA damage (P0.01) and apoptotic cell death (free drugs 34.5% vs. MNP-coated drugs 53.5%, P=0.001).

Conclusions: TMZ and ABT888 can be incorporated simultaneously into MNPs and thus released to an extended degree and gradually, over time. The nanocarriers were able to enter the tumor cells and release both drugs inside them. The apoptotic effect thus induced was greater than that produced by non-vehiculized drugs.