• Journal of Preventive Medicine and Public Health
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• 제32권1호
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• pp.101-107
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• 1999

Objectives. To determine the effects of exposure to hexavalent chromium, 93 male Sprague-Dawley rats were exposed to hexavalent chromium solution. Methods. Rats were divided into 4 groups and exposed to 0.1ml of 0 mM, 0.4 mM, 2.0 mM, and 10.0 mM potassium chromate in the first experiment, and to 0.1 ml of 0 mM, 20 mM, 40 mM, and 80 mM in the second for consecutive 3 days by tracheal instillation. Three and 10 rats were the controls for the first and the second experiments, respectively. Lung tissues were then removed to measure the 8-hydroxydeoxyguanosine (8-OH-dG) level using the HPLC-ECD method, superoxide dismutase (SOD) activity using the cytochrome C method, and 8-hydroxyguanine endonuclease activity using the oligonucleotide nicking assay. Results. The results showed no significant linear relationship between chromium exposure level and 8-OH-dG level or 8-hydroxyguanine endonuclease activity. In the first experiment, 8-OH-dG level and 8-hydroxyguanine endonuclease activity increased in 0.4 mM group, and then decreased in 2.0 mM and 10.0 mM groups. The correlation coefficients between 8-OH-dG level and 8-hydroxyguanine endonuclease activity was statistically significant (P<0.01), and total SOD activity was elevated by chromium exposure in a dose-dependent manner (P<0.05). In contrast, there was no significant dose-response pattern or correlation in the secod experiment. Conclusions. Based on the fact that there was no linear relationship between chromium dose and 8-OH-dG level or activity of the repair enzyme, it seems unlikely that 8-OH-dG formation is the major mechanism of chromium carcinogenesis.

• Molecular & Cellular Toxicology
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• 제3권4호
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• pp.215-221
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• 2007

Neuronal cell toxicity induced by decreased nitric oxide (NO) production may be caused by modulation of constitutive neuronal NO synthase (nNOS). We used lead acetate ($Pb^{2+}$) to modulate physiological NO release and the related pathways of protein kinases like PKC, CaM-KII, and PKA in CATH.a cells, a dopaminergic cell line that has constitutive nNOS activity. In the cells treated with $Pb^{2+}$, cell viability and modulation (phosphorylation) levels of nNOS were determined by MTT assay and Western blot analysis, respectively. nNOS reductase activity (cytochrome c) was also assessed to compare the phosphorylation site-specific nNOS activity. nNOS activity was also determined by NADPH consumption rates. $Pb^{2+}$ treatment alone increased the phosphorylation of nNOS with decreased reductase activity. The phosphorylation levels increased markedly with decreased nNOS reductase activity, when $Pb^{2+}$ was combined with inhibitors for two (PKC and CaM-KII) or three (PKA, PKC and CaM-KII) protein kinases. Interestingly, when the cells were exposed to $Pb^{2+}$ plus PKC or CaM-KII inhibitor, the nNOS was phosphorylated strongly with the lowest activity. However, the levels of phosphorylated nNOS following $Pb^{2+}$ treatment decreased significantly after combined treatment with the PKA inhibitor, and $Pb^{2+}$-induced suppression of reductase activity did not occur. These results demonstrate that physiological NO release in the neuronal cells exposed to $Pb^{2+}$ can be decreased by PKA-mediated nNOS phosphorylation that may be caused by interactions with PKC and/or CaM-KII.

• Applied Biological Chemistry
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• 제27권2호
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• pp.100-106
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• 1984

신생 쥐 간의 subcellular fraction의 특징과 $6{\alpha}$-steroid hydroxylase의 subcellular localization및 특성을 살펴본 결과는 다음과 같다. 1000g 30초 침전 fraction은 총 DNA의 95%를 차지하므로써 crude nuclei fraction으로 나타났으며 또한 5'-nucleotidase의 specific activity가 높은 것은 파괴되지 않은 세포에 기인된 것으로 생각이 되며, 1450g 10분 침전 fraction은 5'-nucleotidase의 activity가 가장 높으므로 crude plasma membrane fraction으로 동정하였으나 mitochondria가 같이 침전되어 있었으며, 9000g 20분 침전 fraction은 succinate-cytochrome C reductase의 activity가 가장 높아 mitochondria fraction으로 하였고, 105,000g 60분 상등액은 LDH가 가장 높아 cytosol로 하였으며, 105,000g 60분 침전은 남은 부분으로 microsome fraction으로 추정하였다. 각 fraction에 기질인 $3{\beta}$-hydroxy-$5{\alpha}$-pregnan-20-one을 incubation시킨 후의 생성된 steroid를 보면 crude nuclei fraction에서는 pregnadiol($5{\alpha}$-pregnane-$3{\alpha}/{\beta}$, $20{\alpha}$-diol)의 형성으로 $20{\alpha}$-reduction과 $3{\alpha}$-$3{\beta}$ iso${\beta}$merization을 볼 수 있었으며 crude plasma membrane fraction에서는 $20{\alpha}$-reduction과 $6{\alpha}$-hydroxylation을 볼 수 있었으며 crude mitochondria와 cytosol에서는 $20{\alpha}$-reduction만을 crude microsome에서는 $16{\alpha}$-hydroxylation을 볼 수 있었으므로 $6{\alpha}$-hydroxylase는 crude plasma membrane에 존재함을 확인하였다. 한편 $6{\alpha}$-steroid hydroxylase에 존재함을 확인하였다. 한편 $6{\alpha}$-steroid hydroxylase의 최대 활성도는 pH 7에서 나타났으며 progesterone은 hydroxylation을 시키지 못한 반면 $3{\alpha}$-hydroxy-$5{\alpha}$-pregnan-20-one은 $6{\alpha}$-hydroxylation이 되었다.

• 한국식품영양과학회지
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• 제45권12호
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• pp.1708-1716
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• 2016

Akt 및 mTOR는 세포 생존에 필수적인 경로로 세포 성장과 증식 등에서 중요한 역할을 하는 것으로 알려져 있다. 본 연구에서는 항암 및 항균 효과가 있는 것으로 알려진 개똥쑥(Artemisia annua L.)에 의한 HepG2 간암세포의 apoptosis 유도 효과를 확인하였다. 본 연구 결과에 의하면 개똥쑥 추출물의 처리 농도가 증가함에 따라 HepG2 세포의 생존율은 억제되었으며, 이는 apoptosis 유도 효과에 의한 것임을 세포의 형태적 변화와 flow cytometry를 통해 확인하였다. 그리고 mitopotential assay와 caspase-3/7 activity assay, western blotting으로 Bcl-2 family 단백질을 확인함으로써 apoptosis 경로 중 내인성 경로(intrinsic pathway)에 의해 apoptosis가 일어남을 알 수 있었다. 이러한 효과는 Akt/mTOR의 활성 저해와 연관이 있었으며 Akt/mTOR의 저해제인 LY294002/rapamycin을 개똥쑥 추출물과 병행처리하였을 경우 개똥쑥 추출물에 의한 apoptosis 효과를 더욱 증대시켰다. 따라서 Akt/mTOR의 저해는 개똥쑥 추출물의 apoptosis 효과를 상승시켰으며 이에 따라 미토콘드리아의 기능 손상과 caspase 활성의 증가를 통해 이루어짐을 확인하였다.

• 동의생리병리학회지
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• 제27권1호
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• pp.43-48
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• 2013

Cisplatin is a anti-neoplastic agent which is commonly used for the treatment of solid tumor. Cisplatin activates multiple signal transduction pathways involved in the stress-induced apoptosis in a variety of cell types. Previous study reported that cisplatin induces apoptosis through activation of ERK, p38 and JNK in rat mesangial cells, but apoptotic pathway remain known. The present study investigated the apoptotic pathway for cisplatin-indcued apoptosis in rat mesangial cells. cisplatin-induced apoptosis was associated with activation of caspase-3, caspase-8, caspase-9. Caspase-8 inhibition prevented the activation of both caspase-3 and caspase-9. In addition, cisplatin-induced apoptosis increased the expression of Bax, but not the level of Bcl-2. These change of Bax/bcl-2 ratio caused the release of cytochrome c from mitochondria into cytosol. In previous study, the ethanol extract of Bojungbangam-tang (EBJT) inhibited cisplatin-induced apoptosis in rat mesangial cells through inhibition of ERK and JNK activation. However, EBJT did not increase cell proliferation, because it did not prevent cisplatin-induced G2/M phase arrest. These effect of EBJT may be related to p38 activation. Cisplatin-induced G2/M phase arrest are inhibited by treatment with p38 inhibitor and EBJT in rat mesangial cells. Also, p38 inhibition and EBJT treatment on cisplatin-induced G2/M phase arrest are markedly increased the G0/G1 phase and reduced the sub-G1. In conclusion, anti-apoptotic effet of EBJT did not increases cell proliferation, because EBJT did not reduce p38 activation related to cisplatin-induced G2/M phase arrest.

• Biomolecules & Therapeutics
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• 제28권2호
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• pp.184-194
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• 2020

Histone deacetylase (HDAC) inhibitors represent a novel class of anticancer agents, which can be used to inhibit cell proliferation and induce apoptosis in several types of cancer cells. In this study, we investigated the anticancer activity of MHY4381, a newly synthesized HDAC inhibitor, against human prostate cancer cell lines and compared its efficacy with that of suberoylanilide hydroxamic acid (SAHA), a well-known HDAC inhibitor. We assessed cell viability, apoptosis, cell cycle regulation, and other biological effects in the prostate cancer cells. We also evaluated a possible mechanism of MHY4381 on the apoptotic cell death pathway. The IC₅₀ value of MHY4381 was lower in DU145 cells (IC₅₀=0.31 µM) than in LNCaP (IC₅₀=0.85 µM) and PC-3 cells (IC₅₀=5.23 µM). In addition, the IC₅₀ values of MHY4381 measured in this assay were significantly lower than those of SAHA against prostate cancer cell lines. MHY4381 increased the levels of acetylated histones H3 and H4 and reduced the expression of HDAC proteins in the prostate cancer cell lines. MHY4381 increased G2/M phase arrest in DU145 cells, and G1 arrest in LNCaP cells. It also activated reactive oxygen species (ROS) generation, which induced apoptosis in the DU145 and LNCaP cells by increasing the ratio of Bax/Bcl-2 and releasing cytochrome c into the cytoplasm. Our results indicated that MHY4381 preferentially results in antitumor effects in DU145 and LNCaP cells via mitochondria-mediated apoptosis and ROS-facilitated cell death pathway, and therefore can be used as a promising prostate cancer therapeutic.

• 한국임상수의학회지
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• 제25권3호
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• pp.152-158
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• 2008

We investigated the changes of protein in chronic MI which was occurred with long-term ischemia, without reperfusion. Sprague Dawley (SD) rats were divided into the sham group and the experimental groups (MI groups). The sham group was treated only thoracotomy without ligation for left main descending artery (LMDA) of left coronary artery (LCA), and the experimental groups (MI7d, ligation of LMDA for 7 days and MI30d, ligation of LMDA for 30 days) were conducted an artificial chronic MI. The change of proteins according to passage of times was compared and analyzed on first and second dimension (1 and 2D) sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Among total 46 spots expressed differentially in the sham group versus MI7d and MI30d groups on 2D gel, we selected proteins that the volume of spot was increased in the MI7d and MI30d groups compared with the sham group. After that, the proteins were identified through liquid chromatography/tandem mass spectrometry (LC-MS/MS) analysis. In result, we could obtain many proteins as follows; albumin, glucose regulated protein 58 KDa, similar to tripartite motif protein 50, ubiquinol-cytochrome c reductase core protein II, sarcomeric mitochondrial creatine kinase, ATP synthetase alpha chain (mitochondrial precursor) and creatine kinase. In conclusion, we suggest many changed proteins shown at chronic ischemia after artificial MI and consider that these proteins play an important role in the function of heart after MI.

• Biomolecules & Therapeutics
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• 제18권4호
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• pp.469-476
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• 2010

This study was to investigate the effect of apigenin on the bioavailability of paclitaxel after oral and intravenous administration in rats. The effect of apigenin on P-glycoprotein (P-gp), cytochrome P450 (CYP)3A4 activity was evaluated. The pharmacokinetic parameters of paclitaxel were determined in rats after oral (40 mg/kg) or intravenous (5 mg/kg) administration of paclitaxel with apigenin (0.4, 2 and 8 mg/kg) to rats. Apigenin inhibited CYP3A4 activity with 50% inhibition concentration ($IC_{50}$) of 1.8 ${\mu}M$. In addition, apigenin significantly inhibited P-gp activity. Compared to the control group, apigenin significantly increased the area under the plasma concentration-time curve (AUC, p<0.05 by 2 mg/kg, 59.0% higher; p<0.01 by 8 mg/kg, 87% higher) of oral paclitaxel. Apigenin also significantly (p<0.05 by 2 mg/kg, 37.2% higher; p<0.01 by 8 mg/kg, 59.3% higher) increased the peak plasma concentration ($C_{max}$) of oral paclitaxel. Apigenin significantly increased the terminal half-life ($t_{1/2}$, p<0.05 by 8 mg/kg, 34.5%) of oral paclitaxel. Consequently, the absolute bioavailability (A.B.) of paclitaxel was significantly (p<0.05 by 2 mg/kg, p<0.01 by 8 mg/kg) increased by apigenin compared to that in the control group, and the relative bioavailability (R.B.) of oral paclitaxel was increased by 1.14- to 1.87-fold. The pharmacokinetics of intravenous paclitaxel were not affected by the concurrent use of apigenin in contrast to the oral administration of paclitaxel. Accordingly, the enhanced oral bioavailability by apigenin may be mainly due to increased intestinal absorption caused via P-gp inhibition by apigenin rather than to reduced renal and hepatic elimination of paclitaxel. The increase in the oral bioavailability might be mainly attributed to enhanced absorption in the gastrointestinal tract via the inhibition of P-gp and reduced first-pass metabolism of paclitaxel via the inhibition of the CYP3A subfamily in the small intestine and/or in the liver by apigenin. It appears that the development of oral paclitaxel preparations as a combination therapy is possible, which will be more convenient than the i.v. dosage form.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.978-984
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• 2004

In the course of screening for a novel inhibitor of CDC2, HY558-1 was isolated from a culture broth of Penicillium minioluteum F558. Moreover, it was found that HY558-1 had an effect on both the cell cycle regulation and apoptosis of human cervical adenocarcinoma HeLa cells. A flow cytometric analysis of HeLa cells revealed appreciable cell cycle arrest at the G1 and G2/M phases following treatment with HY558-1. Furthermore, DNA fragmentation due to apoptosis was observed in HeLa cells treated with HY558-1. To obtain further information on the cell cycle arrest and apoptotic induction induced by HY558-1, the expression of certain cell cycle and apoptosis-associated proteins was examined using a Western blot analysis. The results revealed that HY558-1 inhibited the phosphorylation of pRb and decreased the expression levels of CDK2, CDC2, and cyclin A in the cell cycle progression. It was also shown that the level of $p21^{WAF1/CIP1}$ was increased in HeLa cells treated with 0.52 mM of HY558-1. Accordingly, HY558-1 was found to inhibit the proliferation of HeLa cells through the induction of G1 phase arrest by inhibiting pRb phosphorylation via an upregulation of $p21^{WAF1/CIP1}$, and G2/M phase arrest by directly inhibiting CDC2 and cyclin A. Moreover, HeLa cells treated with 0.52 mM of HY558-1 exhibited apoptotic induction associated with the cleavage of Bid and release of cytochrome c from mitochondria into the cytosol. Subsequent investigation of the activation of caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP) suggested that the mitochondrial pathway was primarily involved in the HY558-1-induced apoptosis in HeLa cells.

• Reproductive and Developmental Biology
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• 제36권3호
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• pp.167-172
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• 2012

The key regulators of apoptosis are the interacting protein of the Bcl-2 family. Bcl-2, an important member of this family, blocks cytochrome C release by sequestering pro-apoptotic BH3-only proteins such as Bid, Bad, Bax and Bim. The pro-survival family members (Bcl-2, Bcl-XL, Bcl-W) are critical for cell survival, since loss of any of them causes cell death in certain cell type. However, its role during early porcine embryonic development is not sufficient. In this study, we traced the effects of Bcl-2 inhibitor, ABT-737, on early porcine embryonic development. We also investigated several indicators of developmental potential, including gene expression (apoptosis-related genes) and apoptosis, which are affected by ABT-737. Porcine embryos were cultured in the PZM-3 medium with or without ABT-737 for 6 days. In result, significant differences in developmental potential were detected between the embryos that were cultured with or without ABT-737 ($14.7{\pm}3.0$ vs $30.3{\pm}4.8%$, p<0.05). TUNEL assay showed that the number of containing fragmented DNA at the blastocyst stage increased in the ABT-737 treated group compared with control (4.7 vs 3.7, p<0.05). The mRNA expression of the pro-apoptotic gene Bax increased in ABT-737 treated group (p<0.05), whereas expressions of the anti-apoptotic Bcl-2 family members (Bcl-2, Bcl-XL, Bcl-W) decreased (p<0.05). Also, expressions of the ER stress indicator genes (GRP78, XBP-1 and sXBP-1) increased in ABT-737 treated group (p<0.05). In conclusion, Bcl-2 is closely associated with of apoptosis- and ER stress-related genes expressions and developmental potential in pig embryos.