• Tuberculosis and Respiratory Diseases
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• v.55 no.5
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• pp.488-498
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• 2003

Background : Activation of the transcription factor NF-${\kappa}B$ has been shown to protect cells from tumor necrosis factor-alpha, chemotherapy, and radiation-induced apoptosis. NF-${\kappa}B$-dependent cIAP expression is a major antiapoptotic mechanism for that. NF-${\kappa}B$ activation and cIAP expression in A549 lung cancer cells which is relatively resistant to radiation-induced cell death were investigated for the mechanism of radioresistance. Materials and methods : We used A549 lung cancer cells and Clinac 1800C linear accelerator for radiation. Cell viability test was done by MTT assay. NF-${\kappa}B$ activation was tested by luciferase reporter gene assay, Western blot for $I{\kappa}B{\alpha}$ degradation, and electromobility shift assay. For blocking ${\kappa}B$, MG132 and transfection of $I{\kappa}B{\alpha}$-superrepressor plasmid construct were used. cIAP expression was analyzed by RT-PCR and cIAP2 promoter activity was performed using luciferase assay system. Results : MTT assay showed that cytotoxicity even 48 hr after radiation in A549 cells were less than 20%. Luciferas assay demonstrated weak NF-${\kappa}B$ activation of $1.6{\pm}0.2$ fold compared to PMA-induced $3.4{\pm}0.9$ fold. Radiation-induced $I{\kappa}B{\alpha}$ degradation was observed in Western blot and NF-${\kappa}B$ DNA binding was confirmed by EMSA. However, blocking NF-${\kappa}B$ using MG132 and $I{\kappa}B{\alpha}$-superrepressor transfection did not show any sensitizing effect for radiation-induced cell death. The result of RT-PCR for cIAP1 & 2 expression was negative induction while TNF-${\alpha}$ showed strong expression for cIAP1 & 2. The cIAP2 promoter activity also did not show any change compared to positive control with TNF-${\alpha}$. Conclusion : We conclude that activation of NF-${\kappa}B$ does not determine the intrinsic radiosensitivity of cancer cells, at least for the cell lines tested in this study.

• Molecules and Cells
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• v.20 no.2
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• pp.241-246
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• 2005

PDK-1 activates PI3-kinase/Akt signaling and regulates fundamental cellular functions, such as growth and survival. NF-${\kappa}B$ is involved in the induction of a variety of cellular genes affecting immunity, inflammation and the resistance to apoptosis induced by some anti-cancer drugs. Even though the crucial involvement of the PI3-kinase/Akt pathway in the anti-apoptotic activation of NF-${\kappa}B$ is well known, the exact role of PDK-1 as well as PI3-kinase/Akt in NF-vactivation is not understood. Here we demonstrate that PDK-1 plays a pivotal role in transcriptional activation of NF-${\kappa}B$ by dissociating the transcriptional co-repressor HDAC1 from the p65 subunit of NF-${\kappa}B$. The association of CBP with p65 was not directly modulated by PDK-1 or by PI3-kinase. Etoposide activated NF-${\kappa}B$ through PI3-kinase/Akt, and the transcription activation domain (TAD) of p65 was further activated by wild-type PDK-1. Overexpression of a dominant negative PDK-1 mutant decreased etoposide-induced NF-${\kappa}B$ transcription and further down-regulated the ectopic HDAC1-mediated decrease in NF-${\kappa}B$ transcriptional activity. Thus activation of PDK-1 relieves the HDAC1-mediated repression of NF-${\kappa}B$ that may be related to basal as well as activated transcription by NF-${\kappa}B$. This effect may also explain the role of the PI3-kinase/PDK-1 pathway in the anti-apoptotic function of NF-${\kappa}B$ associated with the chemoresistance of cancer cells.

• Journal of Acupuncture Research
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• v.27 no.3
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• pp.1-13
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• 2010

목적 : 이 연구는 봉약침의 봉독과 그 주요성분인 멜리틴이 NF-${\kappa}B$의 활성억제와 세포자멸사 관련 단백질의 발현 조절을 통하여 세포자멸사를 유도함으로써 전립선 암세포주인 PC-3 세포의 성장을 억제하는지를 확인하고 해당 기전을 살펴보고자 하였다. 방법 : 봉독이나 멜리틴을 처리한 후 PC-3의 성장억제를 관찰하기 위해 WST-1 assay, CCK-8 assay를 시행하였고, 세포자멸사 조절단백질의 변동 관찰에는 western blot analysis를 시행하였고, 세포자멸사와 연관된 NF-${\kappa}B$의 활성 변화를 관찰하기 위해 EMSA를 시행하였으며, PC-3에서 봉독이나 멜리틴과 NF-${\kappa}B$의 상호작용을 관찰하기 위해 transient transfection assay를 시행하여 세포생존율과 NF-${\kappa}B$의 활성 변동을 측정하였다. 결과 : PC-3 세포에 봉독이나 멜리틴을 처리한 후, 전립선암세포의 성장, 세포자멸사의 유발, 세포자멸사 관련 단백질의 발현, NF-${\kappa}B$의 활성, NF-${\kappa}B$의 p50, $IKK{\alpha}$, $IKK{\beta}$ 치환 후 NF-${\kappa}B$의 활성과 PC-3 세포 증식에 미치는 영향을 관찰하여 다음과 같은 결과를 얻었다. 1. PC-3 세포에서 봉독이나 멜리틴을 처리한 후 세포자멸사가 유도되어 세포성장이 억제되었고, 세포자멸사 관련 단백질 중 분리된 PARP, caspase-3, -9는 유의한 증가를, Bcl-2, XIAP, cXIAP2는 유의한 감소를 나타내었다. 2. PC-3 세포에서 봉독이나 멜리틴을 처리한 후 NF-${\kappa}B$의 활성은 유의한 감소를 나타내었다. 3. PC-3 세포에서 NF-${\kappa}B$의 p50, $IKK{\alpha}$, $IKK{\beta}$를 치환하여 작용기를 없애고 봉독이나 멜리틴을 처리하였을 경우에도 NF-${\kappa}B$의 활성이 유의한 감소를 나타내었다. 결론 : 이상의 결과는 봉독이나 멜리틴이 NF-${\kappa}B$의 활성 억제를 통하여 인간 전립선암세포주인 PC-3의 세포자멸사를 유발함으로써 증식억제 효과가 있음을 입증한 것으로, 전립선암의 예방과 치료에 대한 효과적인 치료제 개발에 도움이 될 것으로 기대된다.

• Tuberculosis and Respiratory Diseases
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• v.49 no.3
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• pp.332-342
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• 2000

Background : The importance of pro-inflammatory cytokines, especially tumor necrosis factor $\alpha$ (INF-$\alpha$) and interleukin-1$\beta$ (IL-1$\beta$), have been extensively documented in the generation of inflammatory lung disease. Lung epithelial cells are also actively involved in initiating and maintaining inflammation by producing pro-inflammatory mediators. Understanding the mechanism of pro-inflammatory cytokine expression in lung epithelial cells is crucial to the development of new therapeutic modalities for inflammatory lung disease. Transcription of most pro-inflammatory cytokines is dependent on the activation of NF-${\kappa}B$. However, the relationship between pro-inflammatory cytokine expression and NF-${\kappa}B/I{\kappa}B$ pathway in lung epithelial cells is not clear. Methods : BEAS-2B, A549, Na-H157, NCI-H719 cells were stimulated with IL-$1{\beta}$ or TNF-$\alpha$ at various times, and then IL-8 and TNF-$\alpha$mRNA expressions were assayed by Northern blot analysis. IL-$1{\beta}$ or TNF-$\alpha$-induced NF-${\kappa}B$ activation was assessed by the nuclear translocation of p65 NF-${\kappa}B$ subunit. The degradation of $I{\kappa}B{\alpha}$ and $I{\kappa}B{\beta}$ by IL-$1{\beta}$ or TNF-$\alpha$stimulation was assayed by Western blot analysis. The phosphorylation of $I{\kappa}B{\alpha}$ was evaluated by Western blot analysis after pre-treating cells with proteasome inhibitor followed by IL-$1{\beta}$ or TNF-$\alpha$ stimulation. The basal level of IKK $\alpha$ expression was evaluated by Western blot analysis. Results: $I{\kappa}B{\alpha}$ and $I{\kappa}B{\alpha}$ was rapidly degraded after 5 minutes of incubation with IL-$1{\beta}$ or TNF-$\alpha$ in BEAS-2B, A549, and NCI-H157 cells. The activation of NF-${\kappa}B{\alpha}$ and the induction of IL-8 and TNF-$\alpha$ mRNA expression were observed by IL-$1{\beta}$ or TNF-$\alpha$ stimulation in these cells. In contrast, neither the changes in NF-${\kappa}B/I{\kappa}B$ pathway nor IL-8 and TNF-$\alpha$mRNA expression was induced by IL-$1{\beta}$ or TNF-$\alpha$ stimulation in NCI-H719 cells. IL-$1{\beta}$ and TNF-$\alpha$-induced $I{\kappa}B$ phosphorylation was observed in BEAS-2B, A549, and NCI-H157 cells, but not in NCI-H719 cells. The basal level of IKK$\alpha$ expression was not different between cell. Conclusion : NF-${\kappa}B/I{\kappa}B$ pathway plays an important role in the expression of pro-inflammatory cytokine in most lung epithelial cells. The absence of the effect on NF-${\kappa}B/I{\kappa}B$ pathway in NCI-H719 cells sæms to be due to the defect in the intracellular signal transduction pathway upstream to IKK.

• Journal of Acupuncture Research
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• v.26 no.3
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• pp.39-48
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• 2009

목적 : 이 연구는 봉약침의 주요성분인 멜리틴이 NF-${\kappa}$B의 활성억제를 통하여 세포자멸사를 유도하고, 전립선 암세포주인 DU-145 세포의 성장을 억제하는지를 확인하고 멜리틴의 NF-${\kappa}$B 활성억제기전을 살펴보고자 하였다. 방법 : 멜리틴을 처리한 후 DU-145의 성장억제를 관찰하기 위해 WST-1 assay를 시행하였고, 세포자멸 사의 관찰에는 DAPI stairung assay를 통한 세포형태관찰을 시행하였으며, 염증관련유전자 발현 관찰에는 western blot analysis를 시행하였고, 세포자멸사와 연관된 NF-${\kappa}$B의 활성 변화를 관찰하기 위해 EMSA와 luciferase assay를 시행하였으며, DU-145에서 멜리틴과 NF-${\kappa}$B의 상호작용을 관찰하기 위해 transient transfection assay를 시행 시 세포생존율과 NF-${\kappa}$B의 활성 변동을 측정하였다. 결과 : DU-145 세포에 멜리틴을 처리한 후, 전립선암세포의 성장, 세포자멸사의 유발, 염중관련유전자 발현 및 NF-${\kappa}$B의 활성, NF-${\kappa}$B의 p50 치환 후 NF-${\kappa}$B의 활성과 DU-145 세포 증식에 미치는 영향을 관찰하여 다음과 같은 결과를 얻었다. 1. DU-145 세포에서 멜리틴을 처리한 후 세포자멸사가 유도되어 세포성장이 억제되었다. 2. DU-145 세포에서 멜리틴을 처리한 후 염증관련유전자 발현 및 NF-${\kappa}$B의 활성에 유의한 감소를 나타내었다. 3. DU-145 세포에서 NF-${\kappa}$B의 p50와 IKK들을 치환하여 작용기를 없애고 멜리틴을 처리하였을 경우에도 세포활성 및 NF-${\kappa}$B의 활성의 유의한 감소를 나타내었다.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.52-66
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• 2001

Background : NF-${\kappa}B$ is the most important transcriptional factor in IL-8 gene expression. Triptolide is a new compound that recently has been shown to inhibit NF-${\kappa}B$ activation. The purpose of this study is to investigate how triptolide inhibits NF-${\kappa}B$-dependent IL-8 gene transcription in lung epithelial cells and to pilot the potential for the clinical application of triptolide in inflammatory lung diseases. Methods : A549 cells were used and triptolide was provided from Pharmagenesis Company (Palo Alto, CA). In order to examine NF-${\kappa}B$-dependent IL-8 transcriptional activity, we established stable A549 IL-8-NF-${\kappa}B$-luc. cells and performed luciferase assays. IL-8 gene expression was measured by RT-PCR and ELISA. A Western blot was done for the study of $I{\kappa}B{\alpha}$ degradation and an electromobility shift assay was done to analyze NF-${\kappa}B$ DNA binding. p65 specific transactivation was analyzed by a cotransfection study using a Gal4-p65 fusion protein expression system. To investigate the involvement of transcriptional coactivators, we perfomed a transfection study with CBP and SRC-1 expression vectors. Results : We observed that triptolide significantly suppresses NF-${\kappa}B$-dependent IL-8 transcriptional activity induced by IL-$1{\beta}$ and PMA. RT-PCR showed that triptolide represses both IL-$1{\beta}$ and PMA-induced IL-8 mRNA expression and ELISA confirmed this triptolide-mediated IL-8 suppression at the protein level. However, triptolide did not affect $I{\kappa}B{\alpha}$ degradation and NF-$_{\kappa}B$ DNA binding. In a p65-specific transactivation study, triptolide significantly suppressed Gal4-p65T Al and Gal4-p65T A2 activity suggesting that triptolide inhibits NF-${\kappa}B$ activation by inhibiting p65 transactivation. However, this triptolide-mediated inhibition of p65 transactivation was not rescued by the overexpression of CBP or SRC-1, thereby excluding the role of transcriptional coactivators. Conclusions : Triptolide is a new compound that inhibits NF-${\kappa}B$-dependent IL-8 transcriptional activation by inhibiting p65 transactivation, but not by an $I{\kappa}B{\alpha}$-dependent mechanism. This suggests that triptolide may have a therapeutic potential for inflammatory lung diseases.

• Journal of Acupuncture Research
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• v.23 no.3
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• pp.91-102
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• 2006

목적 : 이 연구에서는 FBS에 의하여 유도되는 혈관 평활근 세포 증식에 대한 봉약침액과 Melittin의 세포 고사효과의 영향 및 작용 기전을 살펴보고자 하였다. 방법 : $I{\kappa}Ba$, p-$I{\kappa}Ba$, p-ERK1/2, p-Akt, p53, Bcl-2, Bax 및 active caspase-3는 Western blotting을, $NF-{\kappa}B$는 EMSA와 immunofluorescence staining을 이용하여 측정하였다. 결과 : 1. Melittin은 $NF-{\kappa}B$ 활성에 대하여 $I{\kappa}Ba$의 인산화를 유의하게 익제하고 $I{\kappa}Ba$를 증가시켰으며, $NF-{\kappa}B$의 DNA 결합과 $NF-{\kappa}B$ p50의 핵 내 유입을 유의하게 감소시켰다. 2. Melittin은 $NF-{\kappa}B$ 활성을 증가시키는 물질인 Akt의 인산화를 유의하게 억제하였고, ERK1/2의 인산화도 억제하였다. 3. Melittin은 세포사멸 전구 단백질인 p53, Bax 및 caspase-3의 발현을 유의하게 증가시켰고, 세포사멸억제 단백질인 Bcl-2의 발현은 감소시켰다. 결론 : 이상의 결과는 $NF-{\kappa}B$ 와 Akt 활성을 억제함으로써 혈관평활근세포 증식을 억제하는 효과가 있음을 입증한 것이며, 향후 안전성 연구를 바탕으로 혈관성형술 후 재발성협착증과 동맥경화증의 치료제로 사용될 수 있을 것으로 기대된다.

• Development and Reproduction
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• v.15 no.1
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• pp.25-30
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• 2011

Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self renewal requires many factors such as Oct4, Sox2, FoxD3, and Nanog. NF-${\kappa}B$ is a transcription factor involved in many biological activities. Expression and activity of NF-${\kappa}B$ increase upon differentiation of ES cells. Reportedly, Nanog protein directly binds to NF-${\kappa}B$ protein and inhibits its activity in ES cells. Here, we found a potential binding site of NF-${\kappa}B$ in the human Nanog promoter and postulated that NF-${\kappa}B$ protein may regulate expression of the Nanog gene. We used human embryonic carcinoma (EC) cells as a model system of ES cells and confirmed decrease of Nanog and increase of NF-${\kappa}B$ upon differentiation induced by retinoic acid. Although deletion analysis on the DNA fragment including NF-${\kappa}B$ binding site suggested involvement of NF-${\kappa}B$ in the negative regulation of the promoter, site-directed mutation of NF-${\kappa}B$ binding site had no effect on the Nanog promoter activity. Furthermore, no direct association of NF-${\kappa}B$ with the Nanog promoter was detected during differentiation. Therefore, we conclude that NF-${\kappa}B$ protein may not be involved in transcriptional regulation of Nanog gene expression in EC cells and possibly in ES cells.

• Journal of Microbiology
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• v.37 no.4
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• pp.256-262
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• 1999

Latent membrane protein 1 (LMP1) of the Epstein-Barr virus (EBV) is an integral membrane protein with six transmembrane domains, which is essential for EBV-induced B cell transformation. LMP1 functions as a constitutively active tumor necrosis factor receptor (TNFR) like membrane receptor, whose signaling requires recruitment of TNFR-associated factors (TRAFs) and leads to NF-${\kappa}B$ activation. NF-${\kappa}B$ activation by LMP1 is critical for B cell transformation and has been linked to many phenotypic changes associated with EBV-induced B cell transformation. Deletion analysis has identified two NF-${\kappa}B$ activation regions in the carboxy terminal cytoplasmic domains of LMP1, termed CTAR1 (residues 194-232) and CTAR2 (351-386). The membrane proximal C-terminal domain was precisely mapped to a PXQXT motif (residues 204-208) involved in TRAF binding as well as NF-${\kappa}B$ activation. In this study, we dissected the CTAR2 region, which is the major NF-${\kappa}B$ signaling effector of LMP1, to determine a minimal functional sequence. A series of LMP1 mutant constructs systematically deleted for the CTAR2 region were prepared, and NF-${\kappa}B$ activation activity of these mutants were assessed by transiently expressing them in 293 cells and Jurkat T cells. The NF-${\kappa}B$ activation domain of CTAR2 appears to reside in a stretch of 6 amino acids (residues 379-384) at the end of the carboxy terminus.

• Tuberculosis and Respiratory Diseases
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• v.65 no.6
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• pp.476-486
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• 2008

Background: TRAIL (TNF-related apoptosis inducing ligand) is a newly identified member of the TNF gene family which appears to have tumor-selective cytotoxicity due to the distinct decoy receptor system. TRAIL has direct access to caspase machinery and induces apoptosis regardless of p53 phenotype. Therefore, TRAIL has a therapeutic potential in lung cancer which frequently harbors p53 mutation in more than 50% of cases. However, it was shown that TRAIL also could activates $NF-{\kappa}B$ in some cell lines which might inhibit TRAIL-induced apoptosis. This study was designed to investigate whether TRAIL can activate $NF-{\kappa}B$ in lung cancer cell lines relatively resistant to TRAIL-induced apoptosis and inhibition of $NF-{\kappa}B$ activation using proteasome inhibitor MG132 which blocks $I{\kappa}B{\alpha}$ degradation can sensitize lung cancer cells to TRAIL-induced apoptosis. Methods: A549 (wt p53) and NCI-H1299 (null p53) lung cancer cells were used and cell viability test was done by MTT assay. Apoptosis was confirmed with Annexin V assay followed by FACS analysis. To study $NF-{\kappa}B$-dependent transcriptional activation, a luciferase reporter gene assay was used after making A549 and NCI-H1299 cells stably transfected with IgG ${\kappa}-NF-{\kappa}B$ luciferase construct. To investigate DNA binding of $NF-{\kappa}B$ activated by TRAIL, electromobility shift assay was used and supershift assay was done using anti-p65 antibody. Western blot was done for the study of $I{\kappa}B{\alpha}$ degradation. Results: A549 and NCI-H1299 cells were relatively resistant to TRAIL-induced apoptosis showing only 20~30% cell death even at the concentration 100 ng/ml, but MG132 ($3{\mu}M$) pre-treatment 1 hour prior to TRAIL addition greatly increased cell death more than 80%. Luciferase assay showed TRAIL-induced $NF-{\kappa}B$ transcriptional activity in both cell lines. Electromobility shift assay demonstrated DNA binding complex of $NF-{\kappa}B$ activated by TRAIL and supershift with p65 antibody. $I{\kappa}B{\alpha}$ degradation was proven by western blot. MG132 completely blocked both TRAIL-induced $NF-{\kappa}B$ dependent luciferase activity and DNA binding of $NF-{\kappa}B$. Conclusion: This results suggest that inhibition of $NF-{\kappa}B$ can be a potentially useful strategy to enhance TRAIL-induced tumor cell killing in lung cancer.