• Journal of Life Science
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• v.22 no.1
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• pp.55-61
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• 2012

Akt is known to play an important role in cell proliferation and differentiation, and is also over-expressed in several types of cancer cells. In this study, we explored the anti-proliferative effects of selenium in HT-29 colon cancer cells, mediated through effects on Akt and COX-2. Selenium treatments at different concentrations and for different durations inhibited proliferation of HT-29 colon cancer cells and increased apoptotic cell death. Selenium treatment decreased Akt phosphorylation and COX-2 expression. Treatment with LY294002 (an Akt inhibitor) decreased proliferation of HT-29 cells, while a combined treatment with LY294002 and selenium resulted in even further decreases in cell proliferation. Inactivation of Akt by Akt siRNA treatment abolished these inhibitory effects on cell growth. COX-2 expression decreased in Akt transfected cells compared to non-transfected cells. These results suggest that selenium induced both anti-proliferative and apoptotic effects by inhibiting Akt phosphorylation and COX-2 expression. Selenium treatment also appeared to induce synergistic anti-proliferative effects by inhibition of Akt in HT-29 colon cancer cells.

• BMB Reports
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• v.51 no.10
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• pp.532-537
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• 2018

Prostaglandin $E_2$ ($PGE_2$), a major product of cyclooxygenase-2 (COX-2), plays an important role in the carcinogenesis of many solid tumors, including colorectal cancer. Because $PGE_2$ functions by signaling through $PGE_2$ receptors (EPs), which regulate tumor cell growth, invasion, and migration, there has been a growing amount of interest in the therapeutic potential of targeting EPs. In the present study, we investigated the role of EP4 on the effectiveness of cordycepin in inhibiting the migration and invasion of HCT116 human colorectal carcinoma cells. Our data indicate that cordycepin suppressed lipopolysaccharide (LPS)-enhanced cell migration and invasion through the inactivation of matrix metalloproteinase (MMP)-9 as well as the down-regulation of COX-2 expression and $PGE_2$ production. These events were shown to be associated with the inactivation of EP4 and activation of AMP-activated protein kinase (AMPK). Moreover, the EP4 antagonist AH23848 prevented LPS-induced MMP-9 expression and cell invasion in HCT116 cells. However, the AMPK inhibitor, compound C, as well as AMPK knockdown via siRNA, attenuated the cordycepin-induced inhibition of EP4 expression. Cordycepin treatment also reduced the activation of CREB. These findings indicate that cordycepin suppresses the migration and invasion of HCT116 cells through modulating EP4 expression and the AMPK-CREB signaling pathway. Therefore, cordycepin has the potential to serve as a potent anti-cancer agent in therapeutic strategies against colorectal cancer metastasis.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.50-50
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• 2023

Prostaglandin E2(PGE2), a major product of cyclooxygenase-2 (COX-2), plays an important role in the carcinogenesis of many solid tumors, including colorectal cancer. Because PGE2 functions by signaling through PGE2 receptors (Eps), which regulate tumor cell growth, invasion, and migration, there has been a growing amount of interest in the therapeutic potential of targeting Eps. In the present study, we investigated the role of EP4 on the effectiveness of cordycepin in inhibititing the migration and invasion of HCT116 human colorectal carcinoma cells. Our data indicate that cordycepin suppressed lipopolysaccharide (LPS)-enhanced cell migration and invasion through the inactivation of matrix metalloproteinases (MMP)-9 as well as the down-regulation of COX-2 expression and PGE2 production. These events were shown to be associated with the inactivation of EP4 and activation of AMP-activated protein kinase (AMPK). Moreover, the AMPK inhibitor, compound C, as well as AMPK knockdown via siRNA, attenuated the cordycepin-induced inhibition of EP4 expression. Cordycepin treatment also reduced the activation of CREB. These findings indicate that cordycepin suppresses the migration and invasion of HCT116 cells. Through modulating EP4 expression and the AMPK-CREB signaling pathway. Therefore, cordycepin has the potential to serve as a potent anti-cancer agent in therapeutic strategies against colorectal cancer metastasis.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.267-272
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• 2005

We deposited thin films of organic light-emitting-material $Alq_3$(alumina quinoline) on silicon and slide-glass substrates using thermal evaporation method, and measured spectra of ellipsometry angles ${\Delta}$ and ${\Psi}$ in the photon-energy range of 1.5~5.0 eV using a variable angle spectroscopic ellipsometer. The optical constants, refractive index and extinction coefficient, of $Alq_3$ were determined via the dispersion parameters extracted from the curve-fitting process based on Jellison-Modine dispersion function. The reliability of determined optical constants were verified through the comparison of measured and simulated transmittance curves and the good agreement between simulated absorption-coefficient curves and absorbance spectra measured using a spectrophotometer.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.77-81
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• 2007

We sputtered $TiN_x$ (titanium nitride) thin films on silicon substrates using ultra high vacuum RF magnetron sputtering method, and measured spectra of ellipsometry angles ${\Delta}$ and ${\Psi}$ in the photon-energy range of 1.5-5.0 eV using a variable angle spectroscopic ellipsometer. The optical constants, refractive index and extinction coefficient of the $TiN_x$ films were determined via the dispersion parameters extracted from the curve-fitting process based on Drude+Lorentz oscillator dispersion function. The reliability of determined optical constants were verified through the comparison of between simulated reflectance and reflectance spectra measured using a spectrophotometer.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.461-466
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• 2005

Despite the major advances in the microvascular surgery with success rates of up to 98%, failure and vascular complications still remain even in the experienced hands. Failure of blood to flow across an anastomosis is usually caused by three factors: (1) Technical errors; (2) Undetected damage more proximally or via vasospasm; or (3) A clot or a thrombus. The success of a microvascular surgery depends on the severity of the vascular injury and, proper debridement of an injured vessel, and the failure rate of microvascular anastomosis in cases of trauma is higher as the thrombogenic possibility is increased by the endothelial damage. From January to November in 2003, 460 patients were underwent microvascular surgery(270 replantations and 190 free flap transfers) and re-operations were performed in 15 cases. Cases were reviewed by clinical and operative records. In these cases, causes of post-operative circulation insufficiency were identified as 9 vascular spasms and 6 thromboses at the previous anastomotic site. The average of re-operative success rate was 73%(60% in replantations and 100% in free flaps). In conclusion, through precise postoperative monitoring and assessment, immediate surgical re-exploration could be performed when a vascular complication is suspicious, the success rate of microvascular surgery would be increased more.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3653-3656
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• 2012

Background: A number of effective prevention measures have been introduced in attempts to substantially reduce both the incidence and mortality due to many kinds of cancer. The search for new anti-cancer compounds in foods or in plant medicines is one realistic and promising approach to prevention. Chinese medicines provide a rich pool of novel and efficacious agents for cancer prevention and treatment. Previously it was demonstratrated that hyperin extracted from the Manchurian rhododendron leaf reduces the proliferation of many cancer cells. The present study was carried out to evaluate its effects on human endometrial cancer cell viability and apoptosis and to investigate its mechanisms of action in RL952 cells. Methods: Cell viability was measured using the MTT assay. Intracellular calcium ions were detected using laser-scanning confocal microscopy. The effects of hyperin on apoptosis related proteins in RL952 cells were examined using Western blot analysis. Results: The growth of RL952 cells was inhibited by treatment with hyperin. OD values of caspase-3 and caspase-9 were increased and expression of bcl-2 was increased and bax was decreased in protein levels in RL952 cells after 24 h of hyperin treatment, Moreover, intracellular calcium accumulation occurred in hyperin-treated cells. Conclusion: These results suggest that hyperin may play an important role in tumor growth suppression by inducing apoptosis in human endometrial cells via a $Ca^{2+}$-related mitochondrion apoptotic pathway in RL952 cells.

• Journal of Magnetics
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• v.20 no.3
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• pp.211-214
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• 2015

$Cr_2O_3$ nanoparticles were prepared via one-step reactive laser ablation of Cr in oxygen. The metastable $CrO_2$ phase was obtained through the subsequent oxidation of $Cr_2O_3$ nanoparticles under $O_2$ with gas pressures of up to 40 MPa. The as-prepared $Cr_2O_3$ nanoparticles are spherical or rectangular in shape with sizes ranging from 20 nm to 50 nm. High oxygen pressure annealing is effective in producing meta-stable $CrO_2$ from as-dried $Cr_2O_3$ nanoparticles, and the $Cr_2O_3$ nanoparticles exhibit a weak ferromagnetic behavior with an exchange bias of up to 11 mT that can be ascribed to the interfacial exchange coupling between uncompensated surface spins and the antiferromagnetic core. The $Cr_2O_3/CrO_2$ nanoparticles exhibit an enhanced saturation magnetization and a reduced exchange bias with an increasing faction of $CrO_2$ due to the elimination of uncompensated surface spins over the $Cr_2O_3$ nanoparticles when exposed to a high pressure of $O_2$ and/or possible phase segregation that results in a smaller grain size for both $Cr_2O_3$ and $CrO_2$.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.110-113
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• 2017

The two-dimensional layered $MoS_2$ has high mobility and excellent optical properties, and there has been much research on the methods for using this for next generation electronics. $MoS_2$ is similar to graphene in that there is comparatively weak bonding through Van der Waals covalent bonding in the substrate-$MoS_2$ and $MoS_2-MoS_2$ heteromaterial as well in the layer-by-layer structure. So, on the monatomic level, $MoS_2$ can easily be exfoliated physically or chemically. During the $MoS_2$ field-effect transistor fabrication process of photolithography, when using water, the water infiltrates into the substrate-$MoS_2$ gap, and leads to the problem of a rapid decline in the material's yield. To solve this problem, an epoxy-based, as opposed to a water-based photoresist, was used in the photolithography process. In this research, a hydrophobic $MoS_2$ field effect transistor (FET) was fabricated on a hydrophilic $SiO_2$ substrate via chemical vapor deposition CVD. To solve the problem of $MoS_2$ exfoliation that occurs in water-based photolithography, a PPMA sacrificial layer and SU-8 2002 were used, and a $MoS_2$ film FET was successfully created. To minimize Ohmic contact resistance, rapid thermal annealing was used, and then electronic properties were measured.

• Korean Journal of Microbiology
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• v.31 no.4
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• pp.261-266
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• 1993

A new methyltrophic bacterium which utilizes methanol as a sole source of carbon and energy was isolated from soil. It was Gram-negative, nonmotile, nonspore-forming rod, and strictly aerobic bacterium. Catalase and oxidase activities were present. Nitrate was reduced to nitrite. Vitamins and other growth factors were not required. Generation time was 1.6 hr under the optimal condition. The isolate assimilated methanol via the ribulose mono-phosphate pathway (Enter-Doudoroff varient) and did not have .alpha.-ketoglutarate dehydrogenase. It assimilated ammonia through glutamate dehydrogenase. The guanine plus cytosine content of the DNA was 61.0 mol%. The celular fatty acid composition was primarily straight-chain saturated $C^{16 : 0}$ acids (palmitic acids) and unsaturated $C_{16 :1}$ acid (palmitoleic acids), and the isolate also contained two unidentified $C_{17}$ branched fatty acids. The major ubiquinone was Q-8, and Q-6 and Q-7 were present as minor components. Phosphatidylethanolamine and phosphatidylglycerol were predominantly present, and diphosphatidyglycerol was also detected. Based on the physiological and biochemical properties, the isolate was assigned to a novel species of the genus Methylobacillus, Methylobacillus methanolovorus sp. nov.