Cytotoxic evaluation of doxorubicin in combination with simvastatin against human cancer cells

Doxorubicin is a broad spectrum antibiotic used in the treatment of cancers. Its dose dependent cardiotoxicity is the most serious side effect causing withdrawal of drug from hard chemotherapeutic regimen. Statins are shown to be cytotoxic in concentrations higher than the effective doses for the treatment of hypercholesterolemia (40 mg/day). Co-administration of statins and chemotherapeutic agents suppose to be synergic although there are some controversies in the literature. In this study, cytotoxic effects of doxorubicin alone and in combination with simvastatin on Hela tumor cell line were evaluated. Different concentration of doxorubicin and simvastatin were added to the cultured cells and incubated for 72 h. Cell survival was evaluated using MTT and trypan blue exclusion assays. The results indicated that simvastatin in low concentration (0.25 μM) seems to be growth stimulator although cell viability was reduced in concentrations of ≥2 μM. Doxorubicin alone at all tested concentrations (0.1, 1 and 2 μM) was a cell growth inhibitor. It was also shown that percent cell viability was reduced in a decreasing manner with the following protocols: 1) co-administration of doxorubicin and simvastatin in different concentrations; 2) addition of simvastatin after incubation of cells with doxorubicin and 3) addition of doxorubicin after incubation of cells with simvastatin. It could be concluded that between 3 tested protocols combination of doxorubicin and simvastatin after 72 h incubation, showed the highest cytotoxicity against Hela cells.