• KSBB Journal
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• 제25권6호
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• pp.507-512
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• 2010

In this study, we investigated the ability of luteolin, a plant derived flavonoid on hepatocarcinoma cell growth using HepG2 cell culture system. We found that luteolin increased the Smac/DIABLO releases, a mitochondrial protein that potentiates apoptosis. Luteolin also induced either transcriptional activity or expression of PPAR-gamma, a target of cancer growth that PPAR-gamma agonist sensitizes to apoptosis in certain cancer types. To find the possible upstream target molecules of PPAR-gamma activated by luteolin treatment, we used compound C, a specific inhibitor of AMP-activated protein kinase. Pre-treatment of Compound C significantly restored the activation or expression of PPAR-gamma stimulated by luteolin. This result indicated that AMPK signaling might be involved in the activation or expression of PPAR-gamma signaling pathway stimulated by luteolin. Moreover, we also found that luteolin inhibited the insulin-stimulated Akt phosphorylation as well as AICAR, a specific AMPK activator. These results propose that luteolin significantly induces cancer cell death through modulating survival signal pathways such as PPAR-gamma and Akt. AMPK signaling pathway may be an upstream regulator for survival signal pathways such as PPAR-gamma and Akt stimulated by luteolin.

• 대한원격탐사학회지
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• 제29권3호
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• pp.307-314
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• 2013

The Bidirectional Reflectance Distribution (BRD) effect is critical to interpret the surface information using remotely sensed data. This effect was caused by geometric relationship between sensor, target and solar that is inevitable effect for data of optical sensor. To remove the BRD effect, semi-empirical BRDF models are widely used. It is faster to calculate than physical models and demanded less observation than empirical models. In this study, Ross-Li kernel and Roujean kernel were used respectively in National Aeronautics and Space Administration (NASA) and European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) that are used to compare each other. The semi-empirical model consists of three parts which are isotropic, geometric and volumetric scattering. Each part contained physical kernel and empirical coefficients that were calculated by statistical method. Red and NIR channel of SPOT/VEGETATION product were used to compute Nadir BRDF Adjusted Reflectance (NBAR) over East Asia area from January 2009 to December 2009. S1 product was provided by VITO that was conducted atmospheric correction using Simplified Method of Atmospheric Correction (SMAC). NBAR was calculated using corrected reflectance of red and NIR. Previous study has revealed that Roujean geometric kernel had unphysical values in large zenith angles. We extracted empirical coefficients in three parts and normalized reflectance to compare both BRDF models. Two points located forest in Korea peninsular and bare land in Gobi desert were selected for comparison. As results of time series analysis, both models showed similar reflectance change pattern and reasonable values. Whereas in case of empirical coefficients comparison, different changes pattern of values were showed in isotropic coefficients.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5797-5804
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• 2013

In order to enhance the bioavailability of curcumin its conjugates with piperic acid and glycine were synthesized by esterifying the 4 and 4' phenolic hydroxyls, the sites of metabolic conjugation. Antiproliferative and apoptotic efficacy of synthesized conjugates was investigated in MCF-7 and MDA-MB-231 cell lines. $IC_{50}$ values of di-O-glycinoyl (CDG) and di-O-piperoyl (CDP) esters of curcumin were found to be comparable with that of curcumin. Both conjugates induced chromatin condensation fragmentation and apoptotic body formation. CDP exposure to MCF-7 cells induced apoptosis initiating loss of mitochondrial membrane potential (${\Delta}{\Psi}m$) followed by inhibition of translocation of transcription factor NF-${\kappa}B$ and release of Cytochrome-C. Reactive oxygen species (ROS) production was evaluated by fluorescent activated cell sorter. Change in ratio of Bcl2/Bclxl was observed, suggesting permeablization of mitochondrial membrane leading to the release of AIF, Smac and other apoptogenic molecules. DNA fragmentation as a hallmark for apoptosis was monitored by TUNEL as well as agrose gel electrophoresis. Thus, it was proven that conjugation does not affect the therapeutic potential of parent molecule in vitro, while these could work in vivo as prodrugs with enhanced pharmacokinetic profile. Pharmacokinetics of these molecules under in vivo conditions is a further scope of this study.

• 생명과학회지
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• 제19권8호
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• pp.1047-1054
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• 2009

구강편평상피암종은 말기에서 종종 화학치료요법제들이 유도하는 세포자멸사에 저항성을 보인다. 박테리아의 독에 대한 진전된 이해는 암치료에 대한 새로운 치료전략으로 제기되어지고 있다. 본 연구는 Pseudomonas aeruginosa exotoxin A (PEA)가 세포자멸사 기작을 통해 항암제에 저항성을 보이는 YD-9 구강편평상피암종의 생존율을 현격하게 떨어뜨림을 설명하고 있다. 세포자멸사현상은 핵의 형태학적 변화와 DNA 분절 생성을 통해 입증되었다. PEA는 caspase-3, -6, -9 의 분절과 활성화를 일으켰다. 그리고 이러한 반응들은 caspase 의 기질에 해당하는 poly (ADP-ribose) polymerase (PARP), DFF45, 그리고 lamin A 의 단백질 분해를 야기했다. 사립체 막전위 감소, cytochrome c와 Smac/DlABLO의 사립체로부터 세포질로의 유리, 그리고 AIF의 사립체에서 핵으로 이동 등이 관찰되었다. p53, p21 그리고 $14-3-3{\gamma}$는 증가되는 반면 cyclin B와 cdc2는 감소되었다. 이상의 결과들을 종합해 보면 PEA는 caspase를 활성화시키고, 사립체에 변화를 야기시키고 더 나아가서 세포주기 유전자를 조절함으로써 항암제에 대한 강한 저항성을 보이는 YD-9 세포에서 세포자멸사를 유도한다.