[Longikaurin A induces apoptosis of multiple myeloma H929 cells]

The aim of this study was to investigate the biological effect of longikaurin A on multiple myeloma H929 cells. Effects of oridonin and longikaurin A on proliferation of H929 cells were evaluated by CCK-8 assay. Cell morphological features of H929 cells were examined under inverted phase contrast microscope. Apoptosis was determined by Annexin V/PI staining. Expression of caspase-3, caspase-9, and PARP were detected by Western blot. Reactive oxygen species (ROS) level was determined by DCFDA assay. The results showed that longikaurin A (IC(50) 0.85 µmol/L) was more effective than oridonin ((IC(50) 10.66 µmol/L) to inhibit the proliferation of H929 cells. Treatment with longikaurin 2 µmol/L significantly increased the percentage of Annexin V positive cells. Caspase-3 and caspase-9 were activated and PARP, one substrate of caspase-3, was cleaved into 85 kDa fragments. The ROS scavenger N-acetyl-cysteine significantly blocked apoptosis induced by longikaurin A. However, longikaurin A did not increase the ROS level in H929 cells. It is concluded that longikaurin A is more effective than oridonin to induce apoptosis in multiple myeloma H929 cells without increasing the ROS level.