Influence of triptolide on breast cancer apoptosis

AACR Annual Meeting-- Apr 12-16, 2008; San Diego, CA 625 Triptolide, a diterpenoid isolated from the Chinese herb Tripterygium wilfordii Hook.f, has shown antitumor activities in a broad range of solid tumors. However, little is known about the ability of triptolide to induce apoptosis in breast cancer cells. We investigated the effects of triptolide on MCF-7 breast adenocarcinoma cells, and found that it potently induced apoptosis in these cells. Apoptosis was monitored by using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay to measure cell viability; 4’,6-diamidino-2-phenylindole (DAPI) staining to detect chromatin condensation; and cell morphology. Triptolide induced apoptosis of MCF-7 cells in a concentration-dependent manner at very low (nM) concentrations. Utilization of the LysoTracker Green probe revealed that triptolide triggered an increase in the amount of lysosomes present in dying cells. A biochemical assay for lysosomal acid phosphatase showed that the activity of this enzyme increased in experimental cells compared to vehicle-treated cells. In conclusion, triptolide inhibits MCF-7 cell growth by inducing apoptosis and activating lysosomal enzymes. These results suggest that triptolide might be a natural alternative for the treatment of breast cancer. The identification of the mechanisms by which triptolide regulates apoptosis warrant further investigation.