Styryl-lactones such as goniothalamin represent a new class of compounds with potential anti-cancer properties. In this study, we investigated the mechanisms of goniothalamin (GTN), a plant styryl-lactone induced apoptosis in human promyelocytic leukemia HL-60 cells. This plant extract resulted in apoptosis in HL-60 cells as assessed by the externalisation of phosphatidylserine. Using the mitochondrial membrane dye (DIOC(6)) in conjunction with flow cytometry, we found that GTN treated HL-60 cells demonstrated a loss of mitochondrial transmembrane potential (Deltapsi(m)). Further immunoblotting on these cells showed activation of initiator caspase-9 and the executioner caspases-3 and -7. Pretreatment with the pharmacological caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone (Z-VAD.FMK) abrogated apoptosis as assessed by all of the apoptotic features in this study. In summary, our results demonstrate that goniothalamin-induced apoptosis occurs via the mitochondrial pathway in a caspase dependent manner.

Apoptosis induced in primary hepatocytes by transforming growth factor beta1 and staurosporine produced chromatin condensation, DNA cleavage is detected by in situ end-labelling, field inversion and conventional gel electrophoresis, and cell detachment. These effects were abolished by benzyloxycarbonyl-valinylalanylaspartylfluoromethyl ketone, a cleavage-site-directed inhibitor of interleukin-1beta-converting enzyme-like proteases, and this finding suggests that these enzymes are involved in liver apoptosis.

CPP32 as shown by the appearance of the catalytically thioacetamide, 4 during hepatitis virus infection, 5 and involuactive p17 subunit. Loss of pro-Mch3a was also obtion or regression of the liver after withdrawal of the mitogen, served but the catalytically active p19 subunit was not cyproterone acetate. 6 Apoptosis may also be involved in the detected. Staurosporine, which induced a much physiological control of liver size as there is increasing evigreater level of hepatocyte apoptosis, produced a condence that apoptosis in the liver can be induced by external comitant increase in CPP32/Mch3a processing as signalling factors/cytokines. A good example of this is the shown by the appearance of the p17/p19 subunits and anti-Fas antibody that binds to the Fas receptor and produces the corresponding increase in CPP32-like protease acan extensive and lethal apoptotic response in mouse liver. proteases cleave substrates that must have an aspartic acid Received November 5, 1996; accepted March 31, 1997. in the P 1 position, and for ICE the specificity is determinedFor this report the original and commonly recognized names for the ICE-like proteases have been used. However, recently a common, unifying nomenclature has been proposed by four amino acids (including aspartic acid) on the N-termiwhich suggests the adoption of caspase as the generic name. The individual caspases are nal side of the cleavage site, the preferred motif being Tyrthen identified according to their chronological discovery dates. Thus, ICE and CPP32 are Val-Ala-Asp. 22 In the case of CPP32, which is believed to caspases 1 and 3, respectively.

Goniothalamin, a plant styrylpyrone derivative isolated from Goniothalamus andersonii, induced apoptosis in Jurkat T-cells as assessed by the externalisation of phosphatidylserine. Immunoblotting showed processing of caspases-3 and -7 with the appearance of their catalytically active large subunits of 17 and 19 kDa, respectively. Activation of these caspases was further evidenced by detection of poly(ADP-ribose) polymerase cleavage (PARP). Pre-treatment with the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone (Z-VAD.FMK) blocked apoptosis and the resultant cleavage of these caspases and PARP. Our results demonstrate that activation of at least two effector caspases is a key feature of goniothalamin-induced apoptosis in Jurkat T-cells.z 1999 Federation of European Biochemical Societies.