Biomedical subjects

Masao Sato

Publications and source records attributed to Masao Sato.

At least 19 recordsLinked to original sources

PubMed2006

Estrogen-like activity and prevention effect of bone loss in calcium deficient ovariectomized rats by the extract of Pleurotus eryngii.

In the course of a search for natural estrogen-like materials from mushrooms, the proliferating effects of the methanol extracts of 14 edible mushrooms on the estrogen-dependent growth of MCF-7 cells were examined. Of the extracts, that from the fruiting body of Pleurotus eryngii showed the strongest estrogen-like activity, specifically on the proliferating effects of MCF-7 cells. This proliferation effect of the extract from the fruiting body of P. eryngii is related to its estrogenic activity, because this proliferation activity was inhibited by the addition of the antiestrogenic compound ICI 182 780. The ethanol extract of the fruiting body of P. eryngii prevented ovariectomy-induced bone loss. The present data provide evidence that the ethanol extract of P. eryngii helps to protect against the bone loss caused by estrogen deficiency, without having a substantial effect on the uterus.

Animals↗

PubMed2006

A norbergenin derivative inhibits neuronal cell damage induced by tunicamycin.

Several chemically synthesized compounds were examined for protective effects against the cell damage in tunicamycin-treated human neuroblastoma IMR-32 cells. Among the compounds tested, an antioxidant, Norbergenin-11-caproate (10 microM), exhibited complete protection against the cell growth inhibitory effect of tunicamycin but did not inhibit the induction of Bip/GRP78 mRNA by tunicamycin. Both norbergenin-11-caproate and alpha-tocopherol completely inhibited the production of reactive oxygen species induced by tunicamycin, however, alpha-tocopherol inhibited tunicamycin-induced cell damage only partially, even at 100 microM. These findings suggest the potential of Norbergenin-11-caproate for therapeutic application in endoplasmic reticulum (ER) stress-dependent diseases implicating a specific mechanism other than anti-oxidative one.

Benzopyrans↗

PubMed2006

Involvement of oxidative stress in the synthesis of metallothionein induced by mitochondrial inhibitors.

We previously reported that synthesis of metallothionein (MT) was induced by mitochondrial inhibitors such as 2,4-dinitrophenol (DNP) or antimycin A (Kondoh et al., 2001), which are potent inhibitors of mitochondrial respiration. Although the inhibitors are known to be radical generators in mitochondria, the involvement of oxidative stress in the synthesis of MT induced by mitochondrial inhibitors and the biological functions of MT remain obscure. In this study, therefore, we examined the involvement of oxidative stress in MT synthesis induced by mitochondrial inhibitors and the biological functions of MT. In cultured mouse fibroblast cells, the addition of DNP increased both MT concentration and MT mRNA level. Administration of DNP to L-buthionine-SR-sulfoximine (BSO)-pretreated mice increased hepatic lipid peroxidation and induction of MT synthesis. In addition, vitamin E prevented induction of MT synthesis as well as lipid peroxidation in the liver of mice caused by administration of DNP. Administration of mitochondrial inhibitor to mice elevated the levels of lipid peroxidation in the liver and mitochondria, and MT in the liver, indicating the generation of mitochondrial oxidative stress. These data suggest that the induction of MT synthesis by mitochondrial inhibitors is correlated with generation of oxidative stress in mitochondria. Furthermore, the level of DNP-induced alanine aminotransferase (ALT) activity, reflecting hepatic damage, was greater in MT-null mice than in wild-type mice, and intracellular accumulation of reactive oxygen species (ROS) caused by the action of mitochondrial inhibitors was greater in MT-null fibloblast cells than in wild-type cells. The results suggest that MT plays a role as a radical scavenger of intracellular ROS produced in mitochondria. Taken together, the results suggest that mitochondrial oxidative stress induces the synthesis of MT, which may contribute to regulation of mitochondrial ROS production.

2,4-Dinitrophenol↗

PubMed2006

Pigments from Uroleucon nigrotuberculatum induce apoptosis in HL60 human leukemia cells, implicating intracellular oxidative stress and activation of caspases.

Two pigmented compounds from Uroleucon nigrotuberculatum, uroleuconaphin-B(1) [corrected] (H427) and uroleuconaphin-A(1) [corrected] (H373), significantly diminished the cell viability of HL60 cells with IC50 of 10 microM and 30 microM, respectively, in an 18 h-dye uptake assay. Both H427 and H373 augmented the levels of intracellular reactive oxygen species (ROS) and induced apoptosis as demonstrated by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling analysis. ROS augmentation by both H427 and H373 was inhibited by N-acetylcysteine (NAC) and alpha-tocopherol. The apoptosis induced by H427 was inhibited efficiently with NAC and caspase-8 inhibitor but less efficiently with alpha-tocopherol and caspase-9 inhibitor. These findings suggested that these pigments have pro-apoptotic activities via oxidative stress.

Acetylcysteine↗

PubMed2005

Genetic analysis of diet-induced hypercholesterolemia in exogenously hypercholesterolemic rats.

The exogenously hypercholesterolemic (ExHC) rat is an established strain that exhibits a polygenic syndrome of hypercholesterolemia after feeding on a cholesterol-containing diet, and the extent of this differs between male and female rats in the strain. The present study was performed to determine the genetic background of diet-induced hypercholesterolemia in ExHC rats. We used quantitative trait locus (QTL) analyses of the F2 progeny derived from ExHC and Brown-Norway rats. Rats were fed a diet containing 1% cholesterol, and a genome-wide scan was then performed. Significant QTLs for serum total cholesterol levels were revealed on chromosomes 5 and 14 in the vicinity of markers D5Rat95 and D14Rat43, having maximum logarithm of the odds scores of 6.0 and 5.8, respectively. A suggestive QTL for the trait was also detected on chromosome 3 at D3Rat140. In particular, the QTL on chromosome 5 was specific for female rats. These loci were novel QTLs for post-dietary serum total cholesterol levels. In addition, cross-mating analysis in F1 generations suggested that the responsiveness to dietary cholesterol in ExHC rats is partly attributable to X-linked inheritance. Identifying such genetic factors may be useful in predicting the risks associated with diet-induced hypercholesterolemia in humans.

Animals↗

PubMed2005

Quantitative ultrasound can assess the regeneration process of tissue-engineered cartilage using a complex between adherent bone marrow cells and a three-dimensional scaffold.

Articular cartilage (hyaline cartilage) defects resulting from traumatic injury or degenerative joint disease do not repair themselves spontaneously. Therefore, such defects may require novel regenerative strategies to restore biologically and biomechanically functional tissue. Recently, tissue engineering using a complex of cells and scaffold has emerged as a new approach for repairing cartilage defects and restoring cartilage function. With the advent of this new technology, accurate methods for evaluating articular cartilage have become important. In particular, in vivo evaluation is essential for determining the best treatment. However, without a biopsy, which causes damage, articular cartilage cannot be accurately evaluated in a clinical context. We have developed a novel system for evaluating articular cartilage, in which the acoustic properties of the cartilage are measured by introducing an ultrasonic probe during arthroscopy of the knee joint. The purpose of the current study was to determine the efficacy of this ultrasound system for evaluating tissue-engineered cartilage in an experimental model involving implantation of a cell/scaffold complex into rabbit knee joint defects. Ultrasonic echoes from the articular cartilage were converted into a wavelet map by wavelet transformation. On the wavelet map, the percentage maximum magnitude (the maximum magnitude of the measurement area of the operated knee divided by that of the intact cartilage of the opposite, nonoperated knee; %MM) was used as a quantitative index of cartilage regeneration. Using this index, the tissue-engineered cartilage was examined to elucidate the relations between ultrasonic analysis and biochemical and histological analyses. The %MM increased over the time course of the implant and all the hyaline-like cartilage samples from the histological findings had a high %MM. Correlations were observed between the %MM and the semiquantitative histologic grading scale scores from the histological findings. In the biochemical findings, the chondroitin sulfate content increased over the time course of the implant, whereas the hydroxyproline content remained constant. The chondroitin sulfate content showed a similarity to the results of the %MM values. Ultrasonic measurements were found to predict the regeneration process of the tissue-engineered cartilage as a minimally invasive method. Therefore, ultrasonic evaluation using a wavelet map can support the evaluation of tissue-engineered cartilage using cell/scaffold complexes.

Animals↗

PubMed2005

Two-dimensional electrophoretic profiling of normal human kidney glomerulus proteome and construction of an extensible markup language (XML)-based database.

To contribute to physiology and pathophysiology of the glomerulus of human kidney, we have launched a proteomic study of human glomerulus, and compiled a profile of proteins expressed in the glomerulus of normal human kidney by two-dimensional gel electrophoresis (2-DE) and identification with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and/or liquid chromatography-tandem mass spectrometry (LC-MS/MS). Kidney cortices with normal appearance were obtained from patients under surgical nephrectomy due to renal tumor, and glomeruli were highly purified by a standard sieving method followed by picking-up under a phase-contrast microscope. The glomerular proteins were separated by 2-DE with 24 cm immobilized pH gradient strips in the 3-10 range in the first dimension and 26 x 20 cm sodium dodecyl sulfate polyacrylamide electrophoresis gels of 12.5% in the second dimension. Gels were silver-stained, and valid spots were processed for identification through an integrated robotic system that consisted of a spot picker, an in-gel digester, and a MALDI-TOF MS and / or a LC-MS/MS. From 2-DE gel images of glomeruli of four subjects with no apparent pathologic manifestations, a synthetic gel image of normal glomerular proteins was created. The synthetic gel image contained 1713 valid spots, of which 1559 spots were commonly observed in the respective 2-DE gels. Among the 1559 spots, 347 protein spots, representing 212 proteins, have so far been identified, and used for the construction of an extensible markup language (XML)-based database. The database is deposited on a web site (http://www.sw.nec.co.jp/bio/rd/hgldb/index.html) in a form accessible to researchers to contribute to proteomic studies of human glomerulus in health and disease.

Chromatography, Liquid↗

PubMed2005

Cartilage regeneration using mesenchymal stem cells and a three-dimensional poly-lactic-glycolic acid (PLGA) scaffold.

Cartilage engineered from mesenchymal stem cells (MSCs) requires a scaffold to keep the cells in the cartilage defect and to act as a support for inducing hyaline cartilage formation. We developed a novel three-dimensional special poly-lactic-glycolic acid (PLGA) scaffold that provided structural support and stimulated repair. Three-dimensional PLGA scaffolds seeded with cultured MSCs were transplanted into large defects in rabbit knees and analyzed histologically at 4 and 12 weeks after the operation. Our findings showed that in the engineered cartilage with the PLGA scaffold, the defects were filled with smooth, shiny white tissue macroscopically and hyaline-like cartilage histologically at 12 weeks after the transplantation. The structure of the novel PLGA scaffolds provided architectural support for the differentiation of progenitor cells and demonstrated successful induction of in vivo chondrogenesis.

Absorbable Implants↗

PubMed2005

Linoleic acid-rich fats reduce atherosclerosis development beyond its oxidative and inflammatory stress-increasing effect in apolipoprotein E-deficient mice in comparison with saturated fatty acid-rich fats.

The relative benefit of replacing saturated fatty acid with linoleic acids is still being debated because a linoleic acid-enriched diet increases oxidative and inflammatory stresses, although it is associated with a reduction in serum cholesterol levels. The present study was conducted to evaluate the effect of dietary supplementation of linoleic acid-rich (HL) fat, compared with a saturated fatty acid-rich (SF) fat on atherosclerotic lesion areas, serum and liver cholesterol levels, oxidative stress (urinary isoprostanes and serum malondialdehayde) and inflammatory stress (expression of aortic monocyte chemoattractant protein-1; MCP-1) in apo E-deficient mice. Male and female apo E-deficient mice (8 weeks old; seven to eight per group) were fed an AIN-76-based diet containing SF fat (50 g palm oil and 50 g lard/kg) or HL fat (100 g high-linoleic safflower-seed oil/kg) for 9 weeks. Compared with the SF diet, the HL diet lowered atherosclerosis (P<0.05). It reduced serum total cholesterol levels (P<0.05), increased HDL-cholesterol levels (P<0.05) and lowered liver esterified cholesterol levels (P<0.01). The HL diet-fed mice showed increased expression of MCP-1 mRNA (P<0.05), serum levels of malondialdehayde (P<0.05) and urinary excretion of 2,3-dinor-5,6-dihydro-8-iso-prostaglandin F2alpha; P<0.05). These results suggest that having biomarkers in vivo for oxidative stress and inflammatory status of endothelial cells does not necessarily indicate predisposition to an increased lesion area in the aortic root in apo E-deficient mice fed an HL or SF diet.

Animals↗

PubMed2005

Activation of caspase-3 in HL-60 cells treated with pyrithione and zinc.

The transition metal zinc (Zn) is an endogenous regulator of apoptosis. The ability of Zn to modulate apoptosis is believed to be mediated by the regulation of caspase activity. Previously, we reported that an acute influx of labile Zn induced apoptosis via activation of caspase in human leukemia HL-60 cells treated with a Zn ionophore (Py, pyrithione) and Zn at 1 and 25 microM, respectively. In the present study, we investigated the involvement of caspase-3 in Py (1 microM)/Zn (25 microM)-induced apoptosis in HL-60 cells. Pro-caspase-3 is an inactive form of caspase-3. The processing of pro-caspase-3, a sign of caspase-3 activation, occurred 6 h after treatment with Py/Zn. Proteolysis of poly (ADP-ribose) polymerase (PARP), a substrate of caspase-3, was also observed 6 h after treatment with Py/Zn. We also confirmed the elevation of caspase-3 activity as an index of the cleavage of amino acid sequences recognized by activated caspase-3. An inhibitor of caspase-3 attenuated the appearance of the DNA ladder. Taken together, these results indicate that the activation of caspase-3 is partly responsible for the induction of apoptosis in Py/Zn-treated HL-60 cells.

Apoptosis↗

PubMed2004

Expression profiles of zinc transporters in rodent placental models.

Zinc is a vital metal that is a structural and functional component of many proteins. The precise mechanism of zinc transport in the placenta remains unclear. In this study, we investigated the expression of zinc transporters (ZnTs) in the mouse placenta and in two rat trophoblast cell lines, TR-TBT cells, which are syncytiotrophoblast cells of the labyrinth zone, and Rcho-1 cells, which retain trophoblast cell features and differentiate into trophoblast giant cells of the junctional zone. All of the ZnTs that have been identified in mice (ZnT1-7) were detected in the mouse placenta by RT-PCR. The expression profiles of ZnTs in the placenta during pregnancy were different. The mRNA levels of ZnTs, with the exception of ZnT7, did not change during pregnancy. The ZnT7 mRNA level in placenta was elevated during pregnancy. In TR-TBT cells, ZnT1, ZnT3 and ZnT4 were detected by RT-PCR analysis. In Rcho-1 cells, all of the ZnTs that have been identified in rats (ZnT1-4) were detected by RT-PCR analysis. There were no differences between the mRNA expression levels of ZnT family members in undifferentiated Rcho-1 cells and differentiated Rcho-1 cells. This is the first report of expression profiles of ZnTs during differentiation of the placenta in the mouse placenta and rat placental cell models.

Animals↗

PubMed2004

Kaurene diterpene induces apoptosis in human leukemia cells partly through a caspase-8-dependent pathway.

Defects in apoptosis signaling pathways contribute to tumorigenesis and drug resistance, and these defects are often a cause of failure of chemotherapy. Thus, a major goal in chemotherapy is to find cytotoxic agents that restore the ability of tumor cells to undergo apoptosis. We previously found that an Ent-kaurene diterpene, Ent-11alpha-hydroxy-16-kauren-15-one (KD), induced apoptosis in human promyelocytic leukemia HL-60 cells. Here, we found that caspase-8, an apoptotic factor, is involved in KD-induced apoptosis. Although treatment of HL-60 cells with KD resulted in the activation of caspase-8 and -9, a caspase-8-specific inhibitor but not a caspase-9-specific inhibitor attenuated KD-induced apoptosis. Expression of a catalytically inactive caspase-8 partly attenuated KD-induced apoptosis. Treatment with KD led to a time-dependent cleavage of Bid, a substrate of caspase-8, as well as to the proteolytic processing of procaspase-8, indicating that KD treatment induces apoptosis through a caspase-8-dependent pathway. Moreover, overexpression of the drug resistance factor Bcl-2, which is frequently overexpressed in many tumors, failed to confer resistance to KD-induced cytotoxicity. Thus, KD may be a promising experimental cytotoxic agent that possibly points to new strategies to overcome a drug resistance.

Antineoplastic Agents↗

PubMed2004

Phytosterol oxidation products are absorbed in the intestinal lymphatics in rats but do not accelerate atherosclerosis in apolipoprotein E-deficient mice.

Phytosterol oxidation products (oxyphytosterols) are formed during the processing and storage of foods. However, it is unknown whether oxyphytosterols affect human health. To address these issues, we prepared beta-sitosterol and campesterol oxides, evaluated their lymphatic absorption in rats, and examined the effect of an oxyphytosterol diet on atherosclerosis in apolipoprotein (apo) E-deficient mice. The lymphatic absorption of cholesterol and 6 oxyphytosterols (7alpha-hydroxy, 7beta-hydroxy, beta-epoxy, alpha-epoxy, dihydroxy, and 7-keto) of beta-sitosterol or campesterol was assessed in thoracic duct-cannulated rats fed an AIN-93G-based diet containing 2.5 g of cholesterol, oxyphytosterols, or intact phytosterols per kg. Lymphatic recoveries (on a mass basis) of oxycampesterols (15.9 +/- 2.8%, n = 10) and oxysitosterols (9.12 +/- 1.77%, n = 10) were higher than for campesterol (5.47 +/- 1.02%, n = 12, P < 0.05) and beta-sitosterol (2.16 +/- 0.37%, n = 12, P < 0.05), but lower than for cholesterol (37.3 +/- 8.3%, n = 6, P < 0.05). Apo E-deficient mice were fed an AIN-93G-based diet containing 0.2 g oxyphytosterols or intact phytosterols per kg for 9 wk. Diet-derived oxyphytosterols accumulated in the serum, liver, and aorta. Furthermore, the oxyphytosterol diet increased oxycholesterol in the serum compared to the phytosterol diet. However, there was no significant difference between the 2 groups in the serum and aortic cholesterol concentration, the lesion area in the aortic root, or 8-iso-prostaglandin F2alpha concentration in the urine. These results indicate that exogenous oxyphytosterols are well-absorbed and accumulate in the body, but do not promote the development of atherosclerosis in apo E-deficient mice.

Animals↗

PubMed2004

Oxysterol regulation of estrogen receptor alpha-mediated gene expression in a transcriptional activation assay system using HeLa cells.

In order to test the estrogenic activity of sterol oxidation products from cholesterol and phytosterols, an estrogen-dependent gene expression assay was performed in estrogen receptor alpha-stably transformed HeLa cells. The ranking of the estrogenic potency of these compounds was different: 17beta-estradiol >> genistein >> beta-epoxycholesterol = daidzein = cholestanetriol = 22(R)-hydroxycholesterol = 20(S)-hydroxycholesterol = sitostanetriol > campestanetriol = beta-epoxysitosterol = 7beta-hydroxycholesterol. These compounds were not estrogenic in estrogen receptor-negative HeLa cells.

Estrogen Receptor alpha↗

PubMed2004

[Clinical significance of serum IL-18 determination in rheumatoid arthritis].

Interleukin (IL)-18 is a novel cytokine expressing at inflammatory lesion. In this study, to evaluate the clinical significance of IL-18 determination, we have examined serum IL-18, inflammation markers, sFas, and sFas-ligand concentrations in patients with rheumatoid arthritis(RA). Serum was obtained from 56 RA patients aged 35-74 years, 16 osteoarthritis (OA) patients aged 36-78 years and 178 healthy subjects aged 20-72 years and IL-18 was measured by ELISA. Serum IL-18 concentrations in RA (240.1 +/- 15.6 pg/ml, mean +/- SE) were significantly higher than OA (151.8 +/- 12.7 pg/ml, p < 0.005) and healthy controls(141.5 +/- 26.1 pg/ml, p < 0.001). Serum IL-18 levels were significantly increased in II to IV stages of RA (stage II; 218.6 +/- 31.2 pg/ml, stage III; 258.7 +/- 38.4 pg/ml, stage IV; 231.6 +/- 13.1 pg/ml) than those in OA. Furthermore, a positive correlation was observed between serum IL-18 concentration and serum Fas level in patients with RA (r = 0.472), whereas there was no significant correlation between serum IL-18 and sFas-ligand or other inflammatory markers (CRP, RF, CA-RF, IL-6, and IL-8). The present study showed that serum IL-18 level increased in RA, but it is unknown how IL-18 is involved in the pathogenesis of RA. Further study will be necessary to clarify the role of IL-18 in RA.

Adult↗

PubMed2003

The rat STSL locus: characterization, chromosomal assignment, and genetic variations in sitosterolemic hypertensive rats.

BACKGROUND: Elevated plant sterol accumulation has been reported in the spontaneously hypertensive rat (SHR), the stroke-prone spontaneously hypertensive rat (SHRSP) and the Wistar-Kyoto (WKY) rat. Additionally, a blood pressure quantitative trait locus (QTL) has been mapped to rat chromosome 6 in a New Zealand genetically hypertensive rat strain (GH rat). ABCG5 and ABCG8 (encoding sterolin-1 and sterolin-2 respectively) have been shown to be responsible for causing sitosterolemia in humans. These genes are organized in a head-to-head configuration at the STSL locus on human chromosome 2p21. METHODS: To investigate whether mutations in Abcg5 or Abcg8 exist in SHR, SHRSP, WKY and GH rats, we initiated a systematic search for the genetic variation in coding and non-coding region of Abcg5 and Abcg8 genes in these strains. We isolated the rat cDNAs for these genes and characterized the genomic structure and tissue expression patterns, using standard molecular biology techniques and FISH for chromosomal assignments. RESULTS: Both rat Abcg5 and Abcg8 genes map to chromosome band 6q12. These genes span ~40 kb and contain 13 exons and 12 introns each, in a pattern identical to that of the STSL loci in mouse and man. Both Abcg5 and Abcg8 were expressed only in liver and intestine. Analyses of DNA from SHR, SHRSP, GH, WKY, Wistar, Wistar King A (WKA) and Brown Norway (BN) rat strains revealed a homozygous G to T substitution at nucleotide 1754, resulting in the coding change Gly583Cys in sterolin-1 only in rats that are both sitosterolemic and hypertensive (SHR, SHRSP and WKY). CONCLUSIONS: The rat STSL locus maps to chromosome 6q12. A non-synonymous mutation in Abcg5, Gly583Cys, results in sitosterolemia in rat strains that are also hypertensive (WKY, SHR and SHRSP). Those rat strains that are hypertensive, but not sitosterolemic (e.g. GH rat) do not have mutations in Abcg5 or Abcg8. This mutation allows for expression and apparent apical targeting of Abcg5 protein in the intestine. These rat strains may therefore allow us to study the pathophysiological mechanisms involved in the human disease of sitosterolemia.

Animals↗

PubMed2003

Mercuric chloride induces apoptosis via a mitochondrial-dependent pathway in human leukemia cells.

Mercurial compounds modulate immunologic functions by inducing cytotoxicity. Although mercury chloride (HgCl(2)) is known to induce apoptosis in various immune system cells, the mechanism of the induction of apoptosis is poorly understood. In this study, we examined the activation of caspase-3, an important cysteine aspartic protease, during HgCl(2)-induced apoptosis in a human leukemia cell line (HL-60 cells). Both DNA fragmentation, a characteristic of apoptotic cells, and proteolysis of poly(ADP-ribose) polymerase (PARP), a substrate of caspase-3, occurred at 6 h after HgCl(2) treatment in HL-60 cells. These results suggest that the activation of caspase-3 was involved in HgCl(2)-induced apoptosis. The release of cytochrome c (Cyt c) from mitochondria into the cytosol, which is an initiator of the activation of caspase cascades, was also observed in HgCl(2)-treated HL-60 cells. Moreover, the release of Cyt c from mitochondria was observed in HgCl(2)-treated mitochondria isolated from mice liver, and this was followed by mitochondrial permeability transition (PT). The PT was inhibited by cyclosporin A (CsA), a potent inhibitor of PT. CsA also suppressed the occurrence of DNA fragmentation induced by HgCl(2) treatment in HL-60 cells. Taken together, these findings indicate that HgCl(2) is a potent inducer of apoptosis via Cyt c release from the mitochondria in HL-60 cells.

Animals↗

PubMed2003

[Apoptosis-inducing properties of ent-kaurene-type diterpenoids from the liverwort Jungermannia truncata].

Ent-11alpha-hydroxy-16-kauren-15-one (1) induced apoptosis in a human leukemia cell line (HL-60 cells), however, the apoptosis-inducing properties of 1 and its related compounds remain to be proved. We examined the involvement of caspases, a family of cysteine aspartic proteases, which play a central role in induction of apoptosis, in apoptosis induced by the compounds in HL-60 cells. Treatment of the cells with compounds 1, 2 and 3 with the enone group at C-15/C-16 caused DNA fragmentation, a sign of induction of apoptosis, and proteolysis of poly(ADP-ribose) polymerase (PARP), a hallmark of caspase activation. Z-Asp-CH2-DCB, abroad spectrum inhibitor of caspases, abolished the appearance of DNA fragmentation and also significantly attenuated the cytotoxic effects. These data suggest that induction of apoptosis by 1 and some of its related compounds are dependent on caspases activation and might be partly involved in the cytotoxicity in HL-60 cells.

Antineoplastic Agents↗