Mitochondrial apoptosis contributes to the anti-cancer effect of Smilax glabra Roxb.

Smilax glabra Roxb. (SGR), a member of the Smilacaceae family and a rhizome of the Liliaceae plant, has shown anti-inflammation and detoxification properties, and a few studies reported its anti-cancer effect. In this study, we showed that SGR inhibited growth of human breast cancer cell line MCF7, colon carcinoma cell line HT-29, and gastric cancer cell line BGC-823 in a dose-dependent manner. Furthermore, SGR could inhibit tumor growth of HT-29 in Balb/c nude mice and murine hepatoma H22 cells in ICR mice. SGR elicited apoptotic cell death, as confirmed by DNA ladder formation, changes in nuclear morphology, and the increased FITC-Annexin-V/PI staining. Permeabilization of mitochondrial membrane (MMP), production of reactive oxygen species (ROS), elevation of intracellular [Ca(2+)], relocation of cytochrome c, and the activation of caspase-3 were found to be associated with the initiation of apoptosis by SGR treatment. Using microarray analysis, we found the changes in expression profiles of genes related to apoptosis, proliferation and cell cycle control in the cells treated with SGR. Our results demonstrated the mitochondrial regulation of apoptosis by which SGR exerts the anti-cancer effect.