The effect of isolancifolide on the apoptosis in HL-60 cells through caspase-8-dependent and -independent pathways.
Isolancifolide is a compound extracted and isolated from Actinodaphne lancifolia, which is a traditional oriental medicine. To determine whether isolancifolide has therapeutic potential as an anticancer molecule, we assessed its apoptotic effects on HL-60 cells, a human leukemia cell line. Apoptotic activities were investigated using DNA fragmentation assay, immunoblotting, and flow cytometry. We found that the inhibitory concentration 50% of isolancifolide was approximately 20 M. The time- and dose-dependent effects of isolancifolide on apoptosis were determined by DNA fragmentation and propidium iodide staining, and the involvement of caspases and the Bcl-2 family in isolancifolide-induced apoptosis was assessed by Western blotting. During exposure to isolancifolide, the pro-forms or full length of caspases-8, -3, and Bid were decreased, as assessed by Western blotting, while the levels of cleaved forms of caspases-8, -3, and PARP were increased. We observed that the release of cytochrome c and Smac/DIABLO from the mitochondria to the cytosol was accompanied by the loss of mitochondrial membrane potential. The caspase specific inhibitors, z-IETD-fmk and z-LEHD-fmk, blocked the accumulation of sub-G1 cells and the release of cytochrome c, but not that of Smac/DIABLO. These results indicate that isolancifolide induces apoptosis of HL-60 cells through both death receptor and mitochondria pathways, in caspase-8-dependent and -independent manners, suggesting that isolancifolide may be useful in anticancer strategies.
Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongwon 363-883, Korea.
Jeong June
JJ
Choi
Ok-Kyoung
OK
Kwon
Sei-Ryang
SR
Oh
Hyeong-Kyu
HK
Lee
Kyung-Seop
KS
Ahn
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D053181:Caspase 8 / Q000378:metabolism; D061945:Caspase Inhibitors; D004305:Dose-Response Relationship, Drug; D018922:HL-60 Cells; D006801:Humans; D019770:Lauraceae / Q000737:chemistry; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*
D061945:Caspase Inhibitors; D010936:Plant Extracts; C575181:isolancifolide; C505530:CASP8 protein, human; D053181:Caspase 8; D015107:4-Butyrolactone