Abstract
Cis-diammine dichloroplatinum (CDDP) is one of the most important chemotherapeutic agents for cancer treatment. Nonetheless, its notable side effect, nephrotoxicity, undermines its clinical use. The current study was undertaken to evaluate the protective potential of the aqueous extract (AEC) of Cinnamomum cassia (cinnamon) against the cytotoxic effect of CDDP in vitro and to elaborate the molecular mechanism underlying protection.
MTT assay was performed to assess viability of the normal kidney Vero cells treated with CDDP and/or AEC. Cells were stained with Coomassie blue, acridine orange and ethidium bromide to highlight morphological features of apoptosis. Caspase-3 activity, DNA fragmentation and reactive oxygen species (ROS) level were monitored to assess biochemical hallmarks of apoptosis. Quantitative RT-PCR and Western blot analyses were performed to elucidate expression of cellular molecules underlying the protective potential of AEC.
CDDP-treated Vero cells exhibited hallmarks of apoptosis; these hallmarks were significantly suppressed in the presence of AEC. AEC did not alter activity of CDDP-induced cytotoxicity of breast and liver cancer cells. AEC treatment of Vero cells prevented CDDP-induced increased expression of mitochondrial Bax protein, release of mitochondrial cytochrome c, caspase-3 activation, DNA fragmentation and generation of ROS. AEC up-regulated expression of the cytoprotective gene (heme oxygenase (HO)-1).
These findings suggest AEC has protective effects against CDDP-induced toxicity via preventing the activation of various cellular mechanisms mediating apoptotic cell death, without compromising the anticancer efficiency of CDDP. Thus, cinnamon may represent one of the most feasible ways to reduce the risk of CDDP-induced toxicity.