Sarsasapogenin Inhibits Growth and Induces Apoptosis Involving the Blockage of JAK/STAT3 Pathway via ROS-Dependent Mitochondrial Dysfunction on Human Pancreatic Cancer Cells

Background: Sarsasapogenin (SAR), a sapogenin from the Chinese herbal medicine Anemarrhena asphodeloides Bunge (Asparagaceae), is reported to exhibit antitumor effects on cervical cancer. The aim of this study was to explore whether SAR affects pancreatic cancer and the mechanism of this effect. Methods: SAR was applied to treat pancreatic cancer cells (HPAC/PANC-1) and human normal pancreatic cells. To explore the impact of SAR upon pancreatic cancer in vitro, HPAC and PANC-1 cells underwent treatment with 2 or 10 & mu;mol/L SAR and NAcetyl-L-cysteine (NAC), a reactive oxygen species (ROS) inhibitor. Thiazolyl Blue Tetrazolium Bromide (MTT) and colony formation assays were carried out to detect cell growth. Cell apoptosis and cell cycle distribution were assessed using flow cytometry assay. ROS fluorescent images were observed under confocal laser microscope. Mitochondrial membrane potential alterations were measured using JC-1 staining. Expression levels of cleaved caspase-3, cleaved poly (ADP-ribose) polymerase 1 (PARP1), Cyclin D1, Cyclin A, janus-activated kinase (JAK), signal transducer and activator of transcription 3 (STAT3), phosphorylated (p)-JAK and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) were quantitated via Western blot. Results: SAR significantly reduced growth and mitochondrial membrane potential, while significantly promoting apoptosis, cell cycle arrest at G2/M phase and ROS production of pancreatic cancer cells. Besides, SAR significantly augmented cleaved caspase-3 and cleaved PARP1 levels, but significantly down-regulated Cyclin D1, Cyclin A, p-JAK/JAK and p-STAT3/STAT3 levels. NAC significantly reversed the above alterations caused by SAR. Conclusions: SAR exhibits promising efficacy in treating pancreatic cancer involving the blockage of JAK/STAT3 pathway, via ROS-dependent mitochondrial dysfunction.