TRAIL-Mediated Apoptosis in Human Liver Chang Cells / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL)/APO-2L is a member of the TNF family that can kill a wide variety of tumor cells, but not normal cells. This study was designed to investigate the down stream target proteins in TRAIL-mediated apoptosis of human liver, Chang cells. MATERIALS AND METHODS: The expressions of DR4/DR5 in hepatoma cells, including Chang, HepG2 and Hep3B cells, were determined by RT-PCR. Cell viability was measured by MTT assay and apoptosis was assessed by DNA fragmentation assay. The catalytic activity of caspase- family proteases, including caspase-3 and -9, was tested by using fluorogenic biosubstrates. Expression of apoptotic mediators, including procaspase-3 and PARP proteins, was measured by Western blotting. The expression profile of proteins in Chang cells by using two-dimensional (2-D) gel electrophoresis and MALDI-TOF. RESULTS: The results demonstrated that TRAIL (100 ng/ml) induced the apoptotic death of Chang cells, as characterized by the ladder-pattern fragmentation of genomic DNA. TRAIL increased the enzymatic activity of caspase- 3, corresponding to the time of appearance of cleaved PARP and caspase-9. In 2-D gel electrophoresis and MALDI- TOF analysis, the comparison of control versus apoptotic cells in the protein expressions revealed that signal intensity of 7 spots were decreased, whereas 6 spots were increased among 300 spots. These spots were resolved and identified as a protein information by MALDI-TOF. CONCLUSION: We suggested that TRAIL induces the apoptotic death of Chang cells via proteome alterations inducing caspase cascade.

Cadmium-induced Apoptosis in HL-60 Cells Via Signal Transduction / 대한산업의학회지

OBJECTIVES: Apoptosis is a process of active cell death, distinct from necrosis and characterized by specific morphological and biochemical features. Apoptosis induced by metals and metal-related deleterious conditions has only recently been studied. Although the toxic effects of heavy metals are well described, little is known about the mechanism of apoptosis via cadmium toxicity. Therefore, this study is designed to define the induction mechanism of apoptosis by which cadmium exerts its cytotoxic effect on human promyelocytic leukemic HL-60 cells. The cytotoxic effects of cadmium on HL-60 cells are studied in regards to apoptotic signal transduction pathways. METHODS: The mode of cadmium-induced apoptosis was investigated in HL-60 cells. HL-60 cells were treated with various concentrations of cadmium and antioxidants after which the viability of the cells were measured by MTT assay. The morphological features of cadmium- induced apoptosis were evaluated by fluoromicroscopy and the DNA fragmentation was analyzed using 1.5% agarose gel electrophorosis. Kinase activity was assayed by autoradiography and activity of NF-kappaB and nuclear proteins were measured by EMSA. RESULTS: Cadmium (125 microM) induces the characteristic morphological features of apoptosis, which are characterized by a shrinkage of the cytoplasm and a condensation of chromatin. In addition, cadmium induced the ladder pattern of DNA fragmentation. Antioxidants(Sodium nitroprusside, glutathione and N-acethylcysteine), which were not toxic to the cells, did not suppress apoptosis induced by cadmium. Cadmium enhances the expression of several classes of genes at elevated cytotoxic concentrations. Poly(ADP-ribose) polymerase(PARP) was predominantly in the fragmented form when doses of 125 microM were used. Since PARP is cleaved by CPP32 (caspase-3), we next determined if cadmium was capable of effecting changes in CPP32 activity. The results of these experiments showed that cadmium increased caspase-3 activity in a time dependent manner, corresponding to the time of appearance of fragmented PARP. Cadmium also increased the phosphotransferase activities of c-JUN N-terminal kinase (JNK). Furthermore, cadmium increased the activation of transcriptional factors including the activation of protein-1 (AP-1) and NF-kappaB . CONCLUSIONS: These results suggest that cadmium induces the apoptotic death of HL-60 cells via the activation of a DEVD-specific caspase, JNK and transcriptional factors such as AP-1 and NF-kappaB .

Induction of Apoptosis by Heavy Metals in HL-60 Cells / 대한산업의학회지

OBJECTIVES: Apotosis induced by metals and metal-related deleterious conditions has only recently been studied. Although the toxic effects of heavy metal are well described, little is known about the mechanism of apoptosis by heavy metal toxicity. This study is designed to define the induction of apoptosis by which heavy metals exert the cytotoxic effect on human promyelocytic leukemic HL-60 cells. Methods After the incubation with CdC12, Na2SeO3 and HgC12, viability of the cells were measured by MTT assay. DNA fragmentation was analyzed by electrophoresis. For measurement of caspase 1 and 3-like proteases activity, the whole lysates were subjected to the proteolytic cleavage and then measured by using fluorospectrometry. c-JUN N-terminal kinase (JNK) activity was detected by an in vitro kinase assay. Transcriptional activities of activating protein-1 (AP-1) and nuclear factor-kB (NF-kB) were measured by elec trophoresis mobility shift assay (EMSA). RESULTS: Cadmium (l2OuiN/I) and selenium (30,iM) induce the apoptosis of HL-60 cells which is characterized by the ladder pattern of DNA fragmentation. Cadmium and selenium induce the activation of caspase-3 in a time dependent manner. They also increase the phosphotransferase activities of c-JUN N-terminal kinase (JNK) in cadmium and selenium treated HL-60 cells. Furthermore, cadmium and selenium increase the activation of transcriptional factors including AP-i and NF-kB. CONCLUSIONS: These results suggest that cadmium and selenium induce the apoptotic death of HL-60 cells via activation of DEVD-specific caspase, JNK and transcriptional factors such as AP-1 and NF-kB.

The Protective Mechanism of Zinc in Fungal Metabolte Gliotoxin - induced Apoptosis

Gliotoxin, a fungal metabolite, is one of the epipolythiodioxopiperazine classes and has a variety of effects including imrnunomodulatory and apoptotic agents. This study is designed to evaluate the effect of zinc on gliotoxin-induced death of HL-60 cells. Here, we demonstrated that treatment of gliotoxin decreased cell viability in a dose and time-dependent manner. Gliotoxin-induced cell death was confirtned as apoptosis characterized by chromatin marginafion, fragmentation and ladder-pattern digestion of genomic DNA. Gliotoxin increased the proteolytic activities of caspase 3, 6, 8, and 9. Caspase-3 activation was further confirmed by the degradation of procaspase-3 and PARP in gliotoxin-treated HL-60 cells. Zinc compounds including ZnC12 and ZnSO4 markedly inhibited gliotoxin-induced apoptosis in HL-60 cells (from 30% to 90%). Consistent with anti- apoptotic effects, zinc also suppressed the enzymatic activities of caspase-3 and -9 proteases. In addition, cleavage of both PARP and procaspase 3 in gliotoxin-treated HL-60 cells was inhibited by the addition of zinc compounds. We further demonstrated that expression of Fas ligand by gliotoxin was suppressed by zinc compounds. These data suggest that zinc may prevent gliotoxin- induced apoptosis via inhibition of Fas ligand expression as well as suppression of caspase family cysteine proteases-3 and -9 in HL-60 cells.

Effect of Mercury Chloride on Peritoneal Macrophage or EMT-6 cell from Balb/c mice / 대한산업의학회지

The effect of treatment of mercury chloride on the nitrite and nitrate synthesis was observed in peritoneal macrophages from Balb/c mice and EMT-6 cells in vitro. The cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with cytokines. Amounts of nitrite and nitrate in the culture media after 24 and 36 hours of culture were about 2-fold, and 3-fold of those measured after 12 hours respectively. There were very close associations between the amounts of nitrite and nitrate measured in the culture media, according to culture time. The survival rate of peritoneal macrophages was significantly decreased by mercury chloride added into the media in dose-dependent manner, however the survivals of EMT-6 cells were not influenced by mercury chloride concentration in media. Nitrite and nitrate syntheses were dose-dependently decreased by mercury chloride added in culture media. These results reported here suggest that the disorder of cell mediated immunity by mercurials could be related to the inhibition of nitric oxide synthesis which seems to be caused by the inhibition of metabolism of cells.

Effect of Mercury Chloride on Peritoneal Macrophage or EMT-6 cell from Balb/c mice / 대한산업의학회지

The effect of treatment of mercury chloride on the nitrite and nitrate synthesis was observed in peritoneal macrophages from Balb/c mice and EMT-6 cells in vitro. The cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with cytokines. Amounts of nitrite and nitrate in the culture media after 24 and 36 hours of culture were about 2-fold, and 3-fold of those measured after 12 hours respectively. There were very close associations between the amounts of nitrite and nitrate measured in the culture media, according to culture time. The survival rate of peritoneal macrophages was significantly decreased by mercury chloride added into the media in dose-dependent manner, however the survivals of EMT-6 cells were not influenced by mercury chloride concentration in media. Nitrite and nitrate syntheses were dose-dependently decreased by mercury chloride added in culture media. These results reported here suggest that the disorder of cell mediated immunity by mercurials could be related to the inhibition of nitric oxide synthesis which seems to be caused by the inhibition of metabolism of cells.

HgCl2 Dysregulates the Immune Response of Balb/c Mice / 예방의학회지

The studies reported here were undertaken to investigate the effects of mercury chloride on immune system of Balb/c mouse employing a flexible tier of in vitro and in vivo assays. Mercury chloride inhibited the proliferative responses of spleen cells to lipopolysaccharide, pokeweed mitogen, and phytohemagglutinin as a dose-dependent manner. This inhibitory effect was observed not only when HgCl2 was added 2nd or 3rd day of 3 days culture period but also when spleen cells was pretreated with HgC12 for 2 hours. Mercury chloride, however, potentiated the production of IgM and IgG from spleen cells. During the HgCl2 administration by drinking for 3 weeks, the weight gain of mice was significantly blunted than that of control group mice, while no overt signs related to mercury toxicity were noted in any mice of experimental group. There was no change in thymus and spleen weights, and in histological findings of kidney, bone marrow of femur, thymus, spleen, and politeful lymph node after 3 weeks of mercury exposure. However, HgC12 induced a significant increase of total serum IgM, IgG including IgG1, IgG2a and IgG2b, and IgE in Balb/c mice. Treatment in vivo with anti-IL-4 monoclonal antibody significantly abrogated the HgCl2-induced increase in total serum IgG1 and IgE. Whereas HgCl2 potentiated total serum IgM and IgG, there was, there was no difference in total serum hemagglutinin to SRBC(Sheep Red Blood cell) between experimental and control group mice when these mice were immunized with SRBC. All these findings observed in Balb/c mice suggest that mercury perturbates well-orchestrated regulation of immune responses before developing histopathological changes in lymphoid tissues.

Metallothionein induction and its protective effect in liver and kidney of rats exposed to cadmium chloride / 예방의학회지

Tolerance to several toxic effects of cadmium, including lethality has been shown following pretreatment with cadmium and zinc. This study was designed to determine if tolerance also develops to Cd-induced hepatotoxicity and renal toxicity. Three groups of rats (A, B, C), each consisting of 16 rats, were studied and each group was divided into four subgroups (1, 2, 3, 4), 4 rats for each subgroup. Rats were subcutaneously pretreated with saline (A), CdCl2(0.5 mg/kg, B), and ZnCl2 (13.0 mg/kg, C) during time periods of 1~6 weeks. At the end of the period, rats were challenged with CdCl2 (3.0, 6.0 and 9.0 mg/kg, ip). After giving the challenge dose, cadmium and metallothionein (MT) concentrations were determined and also observed the histologic change in liver and kidney. The concentration of cadmium in liver and also observed the increased dose-dependently to the challenge dosage. These data indicate the kidney is a major target organ of chronic cadmium poisoning, and suggest that cadmium induced hepatic injury, via release of Cd-MT, may play and important role in the nephrotoxicity observed in response to long-term exposure to cadmium. In addition, histologic examination of group A2, A3 and A4 revealed moderate to severe cadmium toxicity, evidenced by infiltration of inflammatory cells, cell swelling, pyknosis, enlarged sinusoids and necrosis in liver, and tubule cell necrosis and degeneration in kidney. However, MT concentrations in liver and kidney were increased by the pretreatment of CdCl2 and ZnCl2 and their morphological findings were not significantly changed, comparing with control group. Higher MT concentration in liver and kidney observed in the pretreated groups constitutes a plausible explanation of the protective effects of pretreatment against the cadmium toxicity after challenge dosing.

A Study on the Heavy Metal Contents in Freshwater Fishes of the Mankyung River / 예방의학회지

This study was performed to investigate the heavy metal contents of freshwater fishes. The samples of 24 species were collected at 7 areas located on the Mankyung River during September in 1987. And then the contents of lead, cadmium, copper and zine were analyzed by atomic absorption spectrophotometer. The results were summarized as follows ; 1. The mean value of lead, cadmium, and copper contents of fishes collected in the downstream were significantly higher than those of upstream. 2. The mean lead content of C. auratus was the highest 1.50+/-0.98 microgram/g in viscera and statistically significant difference from muscle content. 3. The mean cadmium content of C. auratus was the highest 0.087+/-0.054 microgram/g and significantly higher than that of muscle, skeleton and gill. 4. In the copper contents, the viscera of C. auratus was the highest 5.25+/-0.94 microgram/g and significantly higher than that of muscle, skeleton and gill. 5. The mean value of zinc content of C. auratus was shown the order of gill, skeleton, viscera and muscle.

Effects of Mitomycin C on Sister Chromatid Exchanges in Cultured Human Lympocytes / 예방의학회지

Sister chromatid exchanges(SCEs) and cell cycle kinetics were proposed as a sensitive and quantitative assay for mutagenicity and cytotoxicity in short-term cultures of phytohemagglutinin(PHA)-stimulated human lymphocytes. Therefore, this study was performed to investigate the relation between the cytotoxic effects and sister chromatid exchanges. The results are summarized as follows: 1) The frequency of SCEs per cell are 13.1+/-2.8 in the lower concentration of 6.25x10(-9) M and 75.8+/-8.2 in the highest concentration of 1.00+/-10(-7) M. Mitotic index is decreased in the higher concentration of mitomycin C. The result indicates that mitomycin C led to a dose dependent increase in SCE frequency, but decrease in mitotic index. 2) Chromosomal analysis was performed on metaphase cells that have divided one, two, and three or more times for cell cycle kinetics by fluorescence-plus-Giemsa(FPG) technique. According to the increased but the cells of third division are greatly decreased. 3) The frequency of SCEs per chromosome by chromocomal group are decreased gradually from A group to G group. But relationships between specific chromosomal group and SCEs frequency are not found.