Dracorhodin perchlorate induces G1/G0 phase arrest and mitochondria-mediated apoptosis in SK-MES-1 human lung squamous carcinoma cells

Dracorhodin perchlorate (DP) has recently been revealed to induce apoptosis in various types of cancer. However, the antitumor potential and molecular mechanisms of DP in human lung cancer have not been previously reported. Therefore, the present study aimed to investigate the effects of DP on cell viability, the cell cycle and apoptosis, using an MTT assay, flow cytometry and western blot studies. DP was identified to induce cellular and DNA morphological changes, and decreased the viability of SK-MES-1 human lung squamous carcinoma cells. DP significantly inhibited the growth of SK-MES-1 cells by inducing apoptosis and G(1)/G(0) cell cycle arrest in a dose-dependent manner via activation of p53 (P<0.05). Furthermore, DP promoted the significant upregulation of B cell lymphoma-2 (Bcl-2)-activated X protein and significant downregulation of Bcl-2 (P<0.05), inducing dissipation of the mitochondrial membrane potential (MMP). In addition, caspase-3 was activated by DP via the cleavage of its substrate, proteolytic cleavage of poly(ADP-ribose) polymerase. DP also induced caspase-independent apoptosis by significantly increasing the protein expression of the apoptosis-inducing factor (P<0.05), which is localized in mitochondria under the physiological conditions and released into the cytoplasm when MMP is dissipated. Furthermore, the present study demonstrated that DP significantly increased the generation of reactive oxygen species (P<0.05). In conclusion, the current study revealed that DP is able to induce cell cycle arrest and apoptosis in SK-MES-1 cells via activation of the mitochondrial pathway, indicating that DP may be a potential leading compound for the development of future lung cancer therapeutic regimes.