• Title, Summary, Keyword: signaling pathway

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Gemcitabine-induced Cell Death in Lung Cancer Cells : the Role of p53 (폐암 세포에서 Gemcitabine에 의한 세포 사멸과 p53의 역할)

  • Kim, Doh-Hyung;Bae, Gang-U;Yong, Wha-Shim;Choi, Eun-Kyung;Kim, Youn-Seup;Park, Jae-Seuk;Jee, Young-Koo;Lee, Kye-Young
    • Tuberculosis and Respiratory Diseases
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    • v.53 no.3
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    • pp.275-284
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    • 2002
  • Background : Gemcitabine is a new anti-cancer agent for treating non-small cell lung cancer. Functioning as an antimetabolite, it induces anti-cancer effects by suppressing DNA synthesis after being incorporated into the DNA as a cytosine arabinoside analogue. When Gemcitabine is incorporated into the DNA, the p53 gene may be activated by induction of the DNA defect. However, there are a few studies on the molecular mechanisms of Gemcitabine-induced cell death. This study examined the role of p53 in Gemcitabine-induced cell death. Methods : A549 and NCl-H358 lung cancer cells were used in this study. The cell viability test was done using a MTT assay at Gemcitabine concentrations of 10nM, 100nM, 1uM, 10uM and 100uM. A FACScan analysis with propium iodide staining was used for the cell cycle analysis. Western blot analysis was done to investigate the extent of p53 activation. For the functional knock-out of p53, stable A549-E6 cells and H358-E6 cells were transfected pLXSN-16E6SD which is over expresses the human papilloma virus E6 protein that constantly degrades p53 protein. The functional knock out of p53 was confirmed by Western blot analysis after treatment with a DNA damaging agent, doxorubicine. Results : Gemcitabine exhibited cell toxicity in dose-dependent fashion. The cell cycle analysis resulted in an S phase arrest. Western blot analysis significant p53 activation in time-dependent manner. Gemcitabine-induced cytotoxicity was reduced by 20-30% in the A549-E6 cells and the 30-40% in H358-E6 cells when compared with the A549-neo and H358-neo control cells. Conclusion : Gemcitabine induces an S phase arrest, as expected for the anti-metabolite, and activates the p53 gene, Furthermore, p53 might play an important role in Gemcitabine-induced cell death. Further investigation into the molecular mechanisms on how Gemcitabine activates the p53 gene and its signaling pathway are recommended.

The expression patterns of RANKL and OPG in murine tooth eruption (치아발육시기에서의 RANKL 및 OPG의 발현 양상)

  • Hwang, Kyung-Mun;Kim, Eun-Jung;Kim, Young-Jin;Nam, Soon-Hyeun;Kim, Hyun-Jung
    • THE JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY
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    • v.33 no.2
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    • pp.290-303
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    • 2006
  • Tooth eruption is a complex and tightly regulated process that involves cells of the tooth organ and the surrounding alveolus. Osteoclast precursors must be recruited into the dental follicle prior to the onset of eruption. This function of dental follicle may be regarded as the ability of bone remodeling characterized by the interaction of osteoclasts and osteoblasts. This is because tooth eruption is a localized event in which many of the genes required for eruption are expressed in the dental follicle. RANKL is a membrane-bound protein that is a member of the TNF ligand family. which is present on bone marrow stromal cells and osteoblasts, and induces osteoclast formation and activation from precursor cell. The biologic effect of RANKL is inhibited by OPG and, in bone, the relative ratio of RANKL and OPG modulates osteoclastogenesis. To evaluate the roles of RANKL and OPG in tooth eruption and the relations with the expression pattern of Runx2, in situ hybridization was performed with mandibles of mice at postnatal stage 1, 3, 5, 7, 9 and 11. mRNA of RANKL, OPG, and Runx2 are expressed in dental follicle and surrounding tissue from P1 to 11. To determine the sites of osteoclastic activity during tooth eruption, mandibles were dissected. Peak osteoclastic activity in alveolar bone along the occlusal and basal regions was observed from P5 to 9, with osteoclasts in these regions being large and strongly TRAP-positive The specific spatio-temporal expression patterns of RANKL, OPG, and Runx2 in our study suggest that tooth eruption could be progressed through the interactions of molecular signaling among dental follicle, dental organ and alveolar bone, furthermore it means that dental follicle is quite important in tooth eruption In addition, it indicates that these genes (RANKL, OPG, and Runx2) play critical roles in tooth eruption.

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Overexpression and Activity Analysis of Cystathionine γ-Lyase Responsible for the Biogenesis of H2S Neurotransmitter (새로운 신경전달물질 H2S 발생 효소, cystathionine γ-lyase의 대량발현 조건과 활성측정)

  • Kim, Kyoung-Ran;Byun, Hae-Jung;Cho, Hyun-Nam;Kim, Jung-Hyun;Yang, Seun-Ah;Jhee, Kwang-Hwan
    • Journal of Life Science
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    • v.21 no.1
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    • pp.119-126
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    • 2011
  • There is a growing recognition of the significance of $H_2S$ as a biological signaling molecule involved in vascular and nervous system functions. In mammals, two enzymes in the transsulfuration pathway, cystathionine ${\beta}$-synthase (CBS) and cystathionine ${\gamma}$-lyase (CGL), are believed to be chiefly responsible for $H_2S$ biogenesis. Genetic inborn error of CGL leads to human genetic disease, cystathioninuria, by accumulating cystathionine in the body. This disease is secondarily associated with a wide range of diseases including diabetes insipidus and Down's syndrome. Although the human CGL (hCGL) overexpression is essential for the investigation of its function, structure, reaction specificity, substrate specificity, and protein-protein interactions, there is no clear report concerning optimum overexpression conditions. In this study, we report a detailed analysis of the overexpression conditions of the hCGL using a bacterial system. Maximum overexpression was obtained in conditions of low culture temperature after inducer addition, performing low aeration during overexpression, and using a low concentration inducer (0.1 mM, IPTG) for induction. Expressed hCGL was purified by His-tag affinity column chromatography and confirmed by Western blot using hCGL antibody and enzyme activity analysis. We also report that the His tag with TEV site attached protein exhibits 76% activity for ${\alpha}-{\gamma}$ elimination reaction with L-cystathionine and 88% for ${\alpha}-{\beta}$ elimination reaction with L-cysteine compared to those of wild type hCGL, respectively. His tag with TEV site attached protein also exhibits a 420 nm absorption maximum, which is attributed to the binding cofactor, pyridoxal 5'-phosphate (PLP).

Antimelanogenic Effect of Ligularia fischeri, Solidago virga-aurea, Aruncus dioicus Extracts from Ullung Island in Murine Melanoma Cells (마우스 악성흑색종세포에서 울릉도 곰취, 미역취, 삼나물 추출물의 멜라닌 생성 억제 효과)

  • Kim, Dong-Hee;An, Bong-Jeun;Kim, Se-Gie;Park, Tae-Soon;Park, Gun-Hye;Son, Jun-Ho
    • Journal of Life Science
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    • v.21 no.2
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    • pp.279-285
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    • 2011
  • The objective of the present study was to evaluate the skin whitening effect of the extracts of 3 herbs, Ligularia fischeri, Solidago virga-aurea and Aruncus dioicus, which were collected from Ullung island. Tyrosinase inhibition activities were 33% in pre-fermented extracts and 45% in post-fermented ones. When tyrosinase activities in B16F10 murine melanoma cells were tested, activities in pre- and post-fermented extracts were 41 and 56.5%, respectively. Thus, the post-fermented extracts might have greater skin whitening effects. The protein expression of MITF, TRP-1, TRP-2, and tyrosinase, which are all skin-whitening related transcription factors, showed that both pre- and post-fermented herbs inhibited protein biosynthesis in B16F10 melanoma cells. Post-fermented herb extracts especially showed a greater decrease of protein expressions. The expression of MITF, a regulatory transcription factor, was also decreased by both extracts but was greater in the post-fermented ones. From the results, it can be concluded that the 3 herb extracts from Ullung island may inhibit melanin biosynthesis by the suppression of MITF activity in a signaling pathway. Results indicate that the post-fermented herbs tested in the present study had skin whitening activities and can be used as functional ingredients for food and cosmetic compositions.

AtCBP63, a Arabidopsis Calmodulin-binding Protein 63, Enhances Disease Resistance Against Soft Rot Disease in Potato (애기장대 칼모듈린 결합 단백질 AtCBP63을 발현시킨 형질전환 감자의 무름병 저항성 증가)

  • Chun, Hyun-Jin;Park, Hyeong-Cheol;Goo, Young-Min;Kim, Tae-Won;Cho, Kwang-Soo;Cho, Hyeon-Seol;Yun, Dae-Jin;Chung, Woo-Sik;Lee, Shin-Woo
    • Journal of Plant Biotechnology
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    • v.38 no.1
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    • pp.62-68
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    • 2011
  • Calmodulin (CaM), a $Ca^{2+}$ binding protein in eukaryotes, mediates cellular $Ca^{2+}$ signals in response to a variety of biotic and abiotic external stimuli. The $Ca^{2+}$-bound CaM transduces signals by modulating the activities of numerous CaM-binding proteins. As a CaM binding protein, AtCBP63 ($\b{A}$rabidopsis thaliana $\b{C}$aM-binding protein $\underline{63}$ kD) has been known to be positively involved in plant defense signaling pathway. To investigate the pathogen resistance function of AtCBP63 in potato, we constructed transgenic potato (Solanum tuberosum L.) plants constitutively overexpressing AtCBP63 under the control of cauliflower mosaic virus (CaMV) 35S promoter. The overexpression of the AtCBP63 in potato plants resulted in the high level induction of pathogenesis-related (PR) genes such as PR-2, PR-3 and PR-5. In addition, the AtCBP63 transgenic potato showed significantly enhanced resistance against a pathogen causing bacterial soft rot, Erwinia carotovora ssp. Carotovora (ECC). These results suggest that a CaM binding protein from Arabidopsis, AtCBP63, plays a positive role in pathogen resistance in potato.

Anti-Inflammmatiry Effects of Nerium indicum Ethanol Extracts through Suppression of NF-kappaB Activation (NF-κB 활성 저해를 통한 협죽도 에탄올 추출물의 항염증 효능)

  • Kim, Tae-Hwan;Ko, Seog-Soon;Park, Cheol;Park, Sang-Eun;Hong, Sang-Hoon;Kim, Byung-Woo;Choi, Yung-Hyun
    • Journal of Life Science
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    • v.20 no.8
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    • pp.1221-1229
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    • 2010
  • Nerium indicum, an India-Pakistan-originated shrub belonging to the oleander family, is reported to possess many pharmacological activities including cardiac muscle stimulation, and anti-diabetes, anti-angiogenesis, anti-cancer and neuro-protective activities. However, the anti-inflammatory properties of N. indicum were unclear. In this study, we investigated the effects of ethanol extract of the N. indicum leaf and stem (ENIL and ENIS) on the expression of anti-inflammatory mediators in U937 human pre-monocytic cell models. In U937 cells stimulated with phorbol 12-myristate-13-acetate (PMA), pre-treatment with ENIS significantly inhibited the expression of both cyclooxygenase-2 (COX-2) mRNA and protein, which are associated with inhibition of the release of prostaglandin $E_2\;(PGE_2)$, whereas the inhibitory effects appeared weakly in ENIL. Moreover, ENIS significantly attenuated PMA-induced IkappaB ($I{\kappa}B$) degradation and suppressed elevated nuclear factor kappa B (NF-${\kappa}B$) nuclear translocation. Taken together, these findings provide important new insights that N. indicum exhibits anti-inflammatory properties by suppressing the transcription of pro-inflammatory cytokine genes through the NF-kB signaling pathway.

Leptin, adiponectin, interleukin-6 and tumor necrosis factor-α in obese adolescents (비만아에서의 leptin, adiponectin, interleukin-6, tumor necrosis factor-α에 대한 연구)

  • Gil, Joo Hyun;Lee, Jung Ah;Kim, Ji Young;Hong, Young Mi
    • Clinical and Experimental Pediatrics
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    • v.51 no.6
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    • pp.597-603
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    • 2008
  • Purpose : Obesity is associated with insulin resistance. Insulin resistance and the presence of pro-inflammatory mediators are thought to cause a state of vascular endothelial dysfunction, an abnormal lipid profile, hypertension, and vascular inflammation. These chronic inflammatory responses, which are characterized by abnormal cytokine production, lead to activation of a pro-inflammatory signaling pathway. Leptin is an important mediator of inflammatory processes and immune-mediated diseases. The purpose of this study was to investigate the relationship between leptin and various cytokines associated with obesity in adolescents. Methods : Sixty-six obese adolescents (between 16-17 years of age, obesity index >130%) and 26 normal controls were included in this study. Obesity index and body mass index (BMI) were calculated. Serum lipid profile, AST and ALT were tested after 10 hours of fasting. Tumor necrosis factor alpha (TNF-${\alpha}$) and Interleukin-6 (IL-6) levels were measured by ELISA. Insulin, adiponectin, and leptin levels were estimated by radioimmunoassay. Results : Leptin was significantly higher in the obese adolescents compared to the control adolescents ($12.0{\pm}6.8ng/mL$ vs $6.3{\pm}1.0ng/mL$). TNF-${\alpha}$, IL-6, and insulin were significantly higher in the obese adolescents. Adiponectin was significantly lower in the obese group than the control group ($3.3{\pm}1.9{\mu}g/mL$ vs $5.0{\pm}1.4{\mu}g/mL$). Leptin had positive correlations with obesity index, BMI, and IL-6. Conclusion : In obese adolescents, leptin, TNF-${\alpha}$, IL-6, and insulin might be important mediators of obesity. Further clinical research is necessary to ascertain leptin as a predictor of cardiovascular diseases and to develop a guideline for clinical intervention.

PGE2 Mediated INF-γ Gene Methylation Through cAMP Signaling Pathway in Human Jurkat T Cells (인간의 Jurkat T세포에서 프로스타글란딘 PGE2) (PGE2)의 cAMP 경로를 통한 인터페론 감마(INF--γ ) 유전자의 methylation)

  • Jeon, Byung-Hun;Ju, Sung-Min;Jeong, Jae-Sung;Kim, Myung-Wan;Yun, Young-Gab;Park, Hyun;Chung Hun-taeg;Han, Dong-Min;Kim, Won-Sin
    • Journal of Life Science
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    • v.14 no.4
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    • pp.670-675
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    • 2004
  • We have examined the effects of S-nitroso-N-acetylpenicillamine (SNAP), prostaglandin $E_2$ (PG $E_2$) and dibutric cyclic AMP (dbcAMP) on the methylation of interferon- ${\gamma}$ (IFN- ${\gamma}$ ) gene in human Jurkat T cells. The CpG dinucleotide which is critical for promoter function of IFN- ${\gamma}$ gene was methylated by treatment with SNAP, PG $E_2$ and dbcAMP, respectively. The DNA methylation induced by PG $E_2$ was suppressed by the addition of 2',5'-dideoxyadenosine (DDA), an inhibitor of adenylyl cyclase, but the suppression was not observed in SNAP treated cells. The NO production was not enhanced in PG $E_2$ or dbcAMP treated cells. The methylation induced by PG $E_2$ and dbcAMP was not suppressed by the addition of $N^{G}$-methyl-L-arginine (L-NMMA), NO synthase inhibitor. In conclusion, the inhibition of INF- ${\gamma}$ gene expression by PG $E_2$ was associated with the methylation of INF- ${\gamma}$ gene by elevation of intracellular cAMP in human Jurkat T cells. However, the methylation induced by PG $E_2$ might not be mediated through the NO production.rough the NO production.

Study on Anti-obesity and Hypoglycemic Effects of Lycium chinense Mill Extracts (구기자 추출물의 항비만 및 혈당강하 효과)

  • Hwang, Eun-Young;Hong, Jung-Hee;Choi, Jun-Hyeok;Choi, Eun-Jung;Lee, In-Seon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.11
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    • pp.1528-1534
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    • 2009
  • This study was designed to evaluate the anti-obesity and hypoglycemic effects of Gugija (Lycium chinense Mill) extracts in 3T3-L1 adipocytes. We investigated the $\alpha$-amylase and $\alpha$-glucosidase inhibitory activities of extracts from Gugija. Gugija was extracted by 70% EtOH and 80% MeOH and aqueous, respectively. A single oral dose of Gugija extract inhibited the increase of blood glucose levels significantly at 0, 30, 60, 90 and 120 min and decreased incremental response areas under the glycemic response curve. These results suggest that Gugija 70% EtOH extracts may delay carbohydrate digestion and reduce postprandial hyperglycemia. In addition, triglyceride content in 3T3-L1 adipocytes decreased at higher concentrations of Gugija 70% EtOH extract. Free fatty acid content in 3T3-L1 adipocytes was increased at higher concentrations of Gugija 70% EtOH extract. Also, glucose transporter 4 (GLUT4), the key insulin signaling pathway transcription factor, was remarkably increased by the Gugija 70% EtOH extract when compared to those of control cells in protein expression levels. Therefore, Gugija can be developed as an effective anti-obesity and hypoglycemic agent.

Characterization of SID2 that is required for the production of salicylic acid by using β-GLUCURONIDASE and LUCIFERASE reporter system in Arabidoposis (리포트 시스템을 이용한 살리실산 생합성 유전자 SID2의 발현 해석)

  • Hong, Mi-Ju;Cheong, Mi-Sun;Lee, Ji-Young;Kim, Hun;Jeong, Jae-Cheol;Shen, Mingzhe;Ali, Zahir;Park, Bo-Kyung;Choi, Won-Kyun;Yun, Dae-Jin
    • Journal of Plant Biotechnology
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    • v.35 no.3
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    • pp.169-176
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    • 2008
  • Salicylic acid(SA) is a phytohormone that is related to plant defense mechanism. The SA accumulation is triggered by abiotic and biotic stresses. SA acts as a signal molecular compound mediating systemic acquired resistance and hypersensitive response in plant. Although the role of SA has been studied extensively, an understanding of the SA regulatory mechanism is still lacking in plants. In order to comprehend SA regulatory mechanism, we have been transformed with a SID2 promoter:GUS::LUC fusion construct into siz1-2 mutant and wild plant(Col-0). SIZ1 encodes SUMO E3 ligase and negatively regulates SA accumulation in plants. SID2(SALICYLIC ACID INDUCTION DEFICIENT2) is a crucial enzyme of SA biosynthesis. The Arabidopsis SID2 gene encodes isochorismate synthase(ICS) that controls SA level by conversion of chorismate to isochorismate. We compared the regulation of SID2 in wild-type and siz1-2 transgenic plants that express SID2 promoter:GUS::LUC constructs respectively. The expressions of $\beta$-GLUCURONIDASE and LUCIFERASE were higher in siz 1-2 transgenic plant without any stress treatment. SID2 promoter:GUS::LUC/siz1-2 transgenic plant will be used as a starting material for isolation of siz1-2 suppressor mutants and genes involved in SA-mediated stress signaling pathway.