Casticin, one of the main components from Fructus Viticis, has been reported to inhibit the growth of various
cancer cells, including the human
cervical cancer cell line HeLa. The purpose of this study was to examine the apoptotic activity and molecular mechanism of
casticin action on human
cervical cancer cells. The apoptotic activity of
casticin on human
cervical cancer HeLa, CasKi, SiHa and peripheral blood mononuclear cells (PBMCs) was measured using a
histone/
DNA ELISA assay, flow cytometry with
propidium iodide (PI) staining and
DNA agarose gel electrophoresis. The mitochondrial membrane potential and
reactive oxygen species (ROS) production were evaluated by flow cytometry analysis.
Caspase activities were assayed using a
caspase colorimetric activity assay kit.
Protein expression levels of
cytochrome c, Bax, Bcl-2, Bcl-xL and XIAP were analyzed by Western blotting.
Casticin caused accumulation of the Sub-G1 cells and increased
reactive oxygen species (ROS) production in HeLa, CasKi, SiHa cell lines, but not in PBMCs. Apoptosis of HeLa cells was induced by
casticin via mitochondrial release of
cytochrome c due to the reduction of mitochondrial trans-membrane potential, activation of
caspase-3 and -9, and the production of
reactive oxygen species. The pan
caspase inhibitor
zVAD-FMK, the
caspase-9 inhibitor zLEHD-fmk and
N-acetylcysteine suppressed
casticin-induced apoptosis. Bax was upregulated, while expression levels of Bcl-xL and XIAP were downregulated. However, there was no change in the expression of Bcl-2 under the same treatment. Our results indicate that
casticin-induced apoptosis of
cervical cancer cells is mediated by ROS generation and mitochondrial signaling pathways.