• Molecules and Cells
• /
• 제28권5호
• /
• pp.495-499
• /
• 2009

Although insulin-like growth factor-I (IGF-I) and androgen receptor (AR) are well known effectors of skeletal muscle, the molecular mechanism by which signaling pathways integrating AR and IGF-I in skeletal muscle cells has not been previously examined. In this study, the role of PI3K/Akt on IGF-I-induced gene expression and activation of AR in skeletal muscle cells was investigated. C2C12 cells were treated with IGF-I in the absence or presence of inhibitors of PI3K/Akt pathway (LY294002 and Wortmannin). Inhibition of the PI3K/Akt pathway with LY294002 or Wortmannin led to a significant decrease in IGF-I-induced AR phosphorylation and total AR protein expression. Furthermore, IGF-I-induced AR mRNA and skeletal ${\alpha}-actin$ mRNA were blocked by LY294002 or Wortmannin. Confocal images showed that IGF-I-induced AR translocation from cytosol to nucleus was inhibited significantly in response to treatment with LY294002 or Wortmannin. The present results suggest that modulating effect of IGF-I on AR gene expression and activation in C2C12 mouse skeletal muscle cells is mediated at least in part by the PI3K/Akt pathway.

• Archives of Pharmacal Research
• /
• 제22권2호
• /
• pp.108-112
• /
• 1999

Recombinant murine stem cell factor (rmSCF) or recombinant murine nerve growth factor (rmNGF) induced the morphological change of large numbers of rat peritoneal mast cells (RPMC). We investigated the role of phosphatidylinositol $3^{l}-kinase$ (PI3-kinase) in receptors-mediated morphological change in RPMC. Exposure of RPMC to PI3-kinase inhibitor, wortmannin, before the addition of rmSCF and rmNGF antagonized those factors-induced morphological change. These results suggest that the PI3-kinase is involved in the signal transduction pathway responsible for morphological change following stimulation of rmSCF and rmNGF and that wortmannin blocks these responses.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제30권1호
• /
• pp.30-40
• /
• 2008

The objectives of this study was to check up the effect of celecoxib, COX-2 inhibitor, on the pathogenesis of oral squamous cell carcinoma. After mefenamic acid, aspirin and celecoxib, COX-2 inhibitor, were inoculated to HN 22 cell line, the following results were obtained through tumor cell viability by wortmannin, growth curve of tumor cell line, apoptotic index, PGE2 synthesis, total RNA extraction, RT-PCR analysis and TEM features. 1. When wortmannin and celecoxib were given together, the survival rate of tumor cells was lowest about 47 %. So wortmannin had an effect on the decrease of survival rate of tumor cells. 2. In growth curve, the slowest growth was observed in celecoxib inoculated group. 3. The synthesis of PGE2 was decreased in all group and the obvious suppression and highest apoptotic index was observed in celecoxib inoculated group. 4. Suppression of expression of COX-2 mRNA was evident in celecoxib inoculated group. But that of COX-1,2 mRNA was observed in mefenamic acid inoculated group and aspirin inoculated group. 5. In celecoxib inoculated group, mRNA expression of AKT1 was decreased and that of PTEN & expression of caspase 3 and 9 was evidently increased. Depending on above results, when celecoxib was inoculated to oral squamous cell carcinoma cell line, an increase of mRNA expression of caspase 3,9 and PTEN is related to a decrease of mRNA expression of AKT1. Wortmannin had an effect on the decrease of survival rate of tumor cells. Celecoxib might induce apoptosis of tumor cell by suppression of AKT1 pathway and COX-2 inhibition. This results suggested that COX-2 inhibitor might be significantly effective in chemoprevention of oral squamous cell carcinoma.

• IMMUNE NETWORK
• /
• 제3권1호
• /
• pp.61-68
• /
• 2003

Background: Fibroblast functions both as a structural element and as a vital immunoregulatory cell. Fibroblasts regulate inflammation through governing of chemokine expression. In order to elucidate the mechanisms by which the expressions of chemokines were regulated, the co-stimulatory effects of Th1 and proinflammatory cytokines were compared using nasal mucosal fibroblasts. Methods: Human nasal mucosa was obtained from surgery for septal deviation and the growth of fibroblasts was established. Fibroblasts from 4th to 6th passage were stimulated with various combinations of cytokines. To inhibit selected signaling pathways, fibroblasts were pretreated with cyclosporin A, wortmannin, staurosporine, and dexamethasone prior to the stimulation with cytokines. The supernatants were collected and chemokines were detected with a sandwich enzyme-linked immunosorbent assay. Results: $TNF-{\alpha}/IFN-{\gamma}$-induced production of RANTES was inhibited by all inhibitors used. MCP-1 was produced constitutively and $TNF-{\alpha}$-induced or $TNF-{\alpha}/IFN-{\gamma}$-induced production of MCP-1 was not inhibited by cyclosporin A or wortmannin, but by stauroporine or dexamethasone. All inhibitors used in this experiment inhibited $TNF-{\alpha}/IFN-{\gamma}$-induced or $IL-1{\beta}/IFN-{\gamma}$-induced production of MCP-2 in nasal mucosal fibroblasts. Although staurosporine or dexamethasone showed strong inhibitory effects, cyclosporin A or wortmannin did not inhibit the production of MCP-3 by $IL-1{\beta}/IFN-{\gamma}$ treatment. Conclusion: Chemokines were strongly induced by stimulation of cytokines in combination and showed different pattern of inhibition by the inhibitors. Therefore, it was assumed that cytokines acted on multiple pathways or on unknown pathways which converged to gene-specific transcription factors.

• 대한임상검사과학회지
• /
• 제39권3호
• /
• pp.249-255
• /
• 2007

While respiratory burst enhances neutrophil glucose utilization, many neutrophil functions are critically influenced by extracellular matrix interaction and phosphoinositide-3-OH kinase (PI3K) signaling. We thus evaluated the role of RGD integrin occupancy and PI3K inhibition on respiratory burst and [18F]FDG uptake of stimulated neutrophils. Human neutrophils were stimulated by 100 ng/mL phorbol-myristate-acetate (PMA), and respiratory burst was measured by cumulative luminescence with lucigenin. [18F]FDG uptake and total hexokinase activity was measured 20 min after PMA stimulation in the presence or absence of soluble RGD peptides (200 g/mL) and/or the PI3K inhibitor wortmannin (200 nM). PMA induced a 71.70.9 fold increase in neutrophil oxygen intermediate generation. [18F]FDG uptake was increased to $194.6{\pm} 3.7%$ and hexokinase activity to $145.0{\pm}2.0%$ of basal levels (both p<0.0005). RGD peptides attenuated respiratory burst activation to $35.6{\pm}0.2%$ (p<0.005), but did not inhibit stimulated [18F]FDG uptake or hexokinase activity. In contrast, without affecting respiratory burst activation, wortmannin inhibited PMA stimulated [18F]FDG uptake to $66.9{\pm}1.6%$ and hexokinase activity to $81.0{\pm}4.2%$ (both P<0.0005), demonstrating its dependence on PI3K activity. Neither RGD nor wortmannin reversed the other's inhibitory effect on stimulated [18F]FDG uptake and hexokinase activity or respiratory burst, which suggests the involvement of distinct signaling pathways. Neutrophil [18F]FDG uptake is enhanced by PMA through a mechanism that requires PI3K activity but is independent of integrin receptor occupancy or respiratory burst activation.

• Preventive Nutrition and Food Science
• /
• 제7권2호
• /
• pp.113-118
• /
• 2002

Alpha-lipoic acid is a known hypoglycemic agent that may be useful in the treatment of diabetes. The objective of this study was to investigate the fate of glucose in isolated muscles incubated with lipoic acid by determining its direct effects on specific metabolic and signaling pathways. Soleus muscles from healthy rats were incubated with lipoic acid in the absence or presence of insulin. Glucose transport, glycogen synthesis, glucose oxidation and lipid synthesis were determined and affects on major pathways associated with insulin signaling were evaluated. Glucose transport was not significantly altered by the addition of lipoic acid to the incubation medium. However, lipoic acid decreased glycogen synthesis in comparison to controls. Glucose oxidation was moderately increased while de-novo lipid synthesis from glucose was inhibited. Wortmannin repressed insulin stimulation of glucose incorporation into glycogen, an effect that was augmented by the combined treatment of wortmannin and lipoic acid. Basal and insulin-stimulated serine phosphorylation of Akt was not changed by the addition of lipoic acid to the incubation medium. These data show that in this in vitro model, lipoic acid did not significantly affect glucose uptake but dramatically modified pathways of glucose metabolism within muscle tissue.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 2004년도 추계학술발표회 발표논문집
• /
• pp.1206-1207
• /
• 2004

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1998년도 공동 춘계학술대회
• /
• pp.57.2-57
• /
• 1998

No Abstract, See Full Text

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.297.2-297.2
• /
• 2002

Previous report showed that histamine release by HCI was mediated via reactive oxygen species (ROS) generation in RBL 2H3 cells. To investigate action of protein kinase on histamine release and ROS generation. we observed effects of protein kinase inhibitors on histamine release and ROS generation in RBL 2H3 cells stimulated by HCI HCI dose-dependently increased both histamine release and ROS generation. HCI-induced histamine release was significantly inhibited by bisindolmaleimide (10 ${\mu}$M). DHC (10 ${\mu}$M). , and wortmannin (10 ${\mu}$M), but not by PD098059 (10 ${\mu}$M). ON the other hand. HCI-induced ROS generation was significantly inhibited by DHC (10 ${\mu}$M). but not by bisindolmaleimide(10 ${\mu}$M). wortmannin (10 ${\mu}$M). and PD098059 (10 ${\mu}$M). However KN-62 did not inhibited both. These results showed that involvement of protein kinase in regulation of histamine release and ROS generation may be different and only tyrosine kinase may be associated with regulation of both histamine release and ROS generation in RBL 2H3 cells.

• Tuberculosis and Respiratory Diseases
• /
• 제54권5호
• /
• pp.551-562
• /
• 2003

연구배경 : NF-${\kappa}B$는 많은 염증 유발성 물질들을 발현시키는데 필요한 전사 인자로서, 염증성 폐질환 발병에 관여한다는 사실이 확인되었다. 이러한 NF-${\kappa}B$의 활성화에는 여러 신호전달 체계가 관여한다는 사실이 밝혀지고 있으며 최근 PI3K/Akt 경로도 NF-${\kappa}B$ 활성화에 관여한다는 연구 결과가 보고되고 있으나, 실험 대상 세포주마다 활성화 기전이 다르고 호흡기 상피세포에 대한 결과도 알려져 있지 않아 호흡기 상피세포에서의 NF-${\kappa}B$ 활성화에 PI3K/Akt 경로가 관여하는지를 밝히기 위하여 본 연구를 시행하게 되었다. 방법 : 인체 기관지 상피세포주인 BEAS-2B와 폐암 세포주인 A549, NCI-H157을 사용하여 Akt 활성화와 $I{\kappa}B{\alpha}$ 분해 여부를 확인하기 위해 western blot을 시행하였다. Wortmannin, LY294002 및 DN-Akt를 이용하여 Akt 경로를 억제하였고, NF-${\kappa}B$ 활성화와 전사 활성을 측정하기 위하여 각각 EMSA와 luciferase assay를 시행하였다. 결과 : BEAS-2B, A549 및 NCI-H157 세포주에 TNF-$\alpha$ 및 insulin을 처리한 경우 Akt 활성화가 유도되었다. Insulin 으로 Akt 경로를 활성화시킨 경우 $I{\kappa}B{\alpha}$ 분해가 일어나지는 않았다. Wortmannin, LY294002 및 DN-Akt 를 이용하여 Akt 경로를 억제한 경우 TNF-$\alpha$에 의한 $I{\kappa}B{\alpha}$ 분해 및 IKK 활성화가 억제되지는 않았으며, NF-${\kappa}B$ 활성화도 억제되지 않았다. Wortmannin을 처리한 경우 TNF-$\alpha$에 의한 NF-${\kappa}B$ 전사 활성이 오히려 증가하는 양상을 보였으나, DN-Akt 이입시킨 경우에는 관찰되지 않았다. 결론 : 인체 호흡기 상피세포에서는 $I{\kappa}B$/NF-${\kappa}B$ 경로의 활성화는 PI3K/Akt 경로와 무관한 것으로 판단된다.