• BMB Reports
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• v.42 no.5
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• pp.260-264
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• 2009

Tumor necrosis factor-$\alpha$ (TNF-$\alpha$) exhibits cytotoxicity towards various tumor cells in vitro and induces apoptotic necrosis in transplanted tumors in vivo. It also shows severe toxicity when used systemically for the treatment of cancer patients, hampering the development of TNF-$\alpha$ as a potential anticancer drug. In order to understand the structure-function relation of TNF-$\alpha$ with respect to receptor binding, we selected four regions on the bottom of the TNF-$\alpha$ trimer that are in close contact with the receptor and carried out mutagenesis studies and computational modeling. From the study, various TNF-$\alpha$ muteins with a high therapeutic index were identified. These results will provide a structural basis for the design of highly potent TNF-$\alpha$ for therapeutic purposes. By conjugating TNF-$\alpha$ muteins with a high therapeutic index to a fusion partner, which targets a marker of angiogenesis, it could be possible to develop TNF-$\alpha$ based anticancer drugs.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1207-1213
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• 2006

Tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$ has been implicated in skeletal diseases by promoting bone loss in inflammatory bone diseases. In the present study, we examined the effects of $TNF-{\alpha}$ on osteoblastic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). $TNF-{\alpha}$ dose-dependently promoted matrix mineralization of hBMSCs with a maximal stimulation at 2ng/ml. $TNF-{\alpha}$ increased expression of alkaline phosphatase, which plays a crucial role for the matrix deposition. The $TNF-{\alpha}-stimulated$ osteoblastic differentiation was not affected by $NF_kB$ inhibitors, BAY and SN50. However, a JNK-specific inhibitor, SP600125 completely abolished the $TNF-{\alpha}-stimulated$ matrix mineralization and expression of alkaline phosphatase. These results suggest that $TNF-{\alpha}$ enhances osteoblastic differentiation of hBMSCs through JNK-dependent pathway.

• Toxicological Research
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• v.11 no.2
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• pp.169-173
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• 1995

The effects of tumor necrosis factor alpha $(TNF-{\alpha})$ on growth and tubular formation of bovine aortic endothelial cells were examined using an in vitro angiogenesis model system. The growth of endothelial cells was enhanced in a dose-dependent manner when the cells were cultured with $TNF-{\alpha}$ for 3 days, but $TNF-{\alpha}$, at the concentration of 1 nM or higher, produced a growth inhibition of endothelial cells when the cells were cultured for 8 days. The endothelial cells incubated with $TNF-{\alpha}$ for 48-h exhibited a typical morphologic change. Then, they showed a fibroblastoid organization of overlapping, elongated, and spindle-shaped cells. $TNF-{\alpha}$, at the concentration of O. 1 nM or higher, inhibited the tubular formation of vascular endothelial cells in an in vitro anglogenesis model using a 3-dimensional culture system.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.1
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• pp.97-101
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• 1999

Male genital tract inflammatory conditions may be associated with unexplained infertility. The presence of cytokine such as tumor necrosis factor-alpha (TNF-${\alpha}$) was reported in the semen of infertile men. However, the effect of these cytokines on human sperm function is still unclear. The purpose of this study was to investigate the in-vitro effects of TNF-alpha on human sperm motility with computer assisted sperm analysis. Washed sperm from 16 normal men were incubated without and with TNF-${\alpha}$ (0.1, 10, 1000 ng/ml). The changes of parameters of sperm motility were recorded at different time intervals (0, 5, 24 hour). There was no significant change of parameters of sperm motility in the incubation with TNF-${\alpha}$. It is suggested that TNF-${\alpha}$ alone does not interfere with the sperm motility and more studies are needed.

• BMB Reports
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• v.29 no.6
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• pp.530-534
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• 1996

Astrocyte are the major glial cell type in the central nervous system (CNS), and analogous to macrophage, mediates the number of immune responses such as production of cytokines including tumor necrosis factor alpha ($TNF-{\alpha}$) upon activation. $TNF-{\alpha}$ has been implicated in neuroimmunological disorders through killing oligodendrocytes and thus causing demyelination. It has been previously demonstrated that mitogen-activated T cells synthesized a 26 kDa precursor form of $TNF-{\alpha}$ which is bound to the surface of a membrane, and is later secreted as a 17 kDa mature version. In order to examine whether astrocytes would produce the transmembrane form of $TNF-{\alpha}$, astrocytes were stimulated with biological stimuli and the membrane form of $TNF-{\alpha}$ was analyzed by Western blot and FACS analysis. When astrocytes are stimulated with lipopolysaccharide (LPS), $IFN-{\gamma}/LPS$, or $IFN-{\gamma}/IL-1{\beta}$, they were able to express a membrane-anchored $TNF-{\alpha}$ of approximately 26 kDa protein which was immunoreactive to an $anti-TNF-{\alpha}$ antibody, whereas unstimulated astrocytes or astrocytes treated with $IFN-{\gamma}$ or $IL-1{\beta}$ alone was not. Our FACS data were also consistent with the immunoblot analysis. Our result suggests that the membrane form of $TNF-{\alpha}$ expressed by activated astrocytes may cause local damage to oligodendrocytes by direct cell-cell contact and contribute to demyelination observed in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE).

• Journal of Life Science
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• v.12 no.2
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• pp.57-60
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• 2002

Apoptosis of vascular smooth muscle cell is observed in the vascular diseases such as atherosclerosis and restenosis. The death of vascular smooth muscle cells can be induced by cytokines and activation of Fas-pathways. It is widely accepted that apoptosis occurs without inflammation. There are, however, reports that apoptosis is not silent. Vascular smooth muscle cells dying by Fas-pathway secreted inflammatory cytokines including monocyte chemoattractant protein-1. This study have investigated whether apoptosis is associated with potent inflammatory cytokine tumor tumor necrosis factor (TNF)-${\alpha}$. The cells which undergo apoptosis by expressing FADD in the absence of tetracycline expressed and secreted TNF-${\alpha}$. When the level of TNF-${\alpha}$ transcript was investigated, dying smooth muscle cells exhibited transcriptional activation of TNF-${\alpha}$. The data indicate that dying vascular smooth muscle cells contribute to inflammation by expressing inflammatory cytokines. The present study suggests that apoptosis could not be silent in certain pathological situations.

• Development and Reproduction
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• v.5 no.2
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• pp.101-106
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• 2001

Present study was aimed to verify the role of insulin and TNF-$\alpha$ in development of preimplantation embryos. Mouse morula were cultured for 40 hr in the presence or absence of insulin(400 ng/ml) and TNF-$\alpha$ (50 ng/ml). The morphological development, cell number of blastomeres per blastocyst, and mitogen activated protein kinase(MAPK) activity were examined. The developmental rate and cell number per embryo were the highest in insulin treatment group and the lowest in TNF-$\alpha$ treatment group. There was no significant difference in developmental rate between control and insulin plus TNF-$\alpha$ group. Taken together, it suggested that TNF-$\alpha$ impaired embryonic development and that insulin rescued developmental impairment imposed by TNF-$\alpha$. In blastocysts, insulin treatment significantly increased MAPK activity. TNF-$\alpha$ decreased the MAPK activity in a concentration-dependent manner. In the TNF-$\alpha$(50 ng/ml) -primed embryos, activation of MAPK by insulin was attenuated. In conclusion, these results suggest that there was a cross talk between insulin and TNF-$\alpha$ by means of activation of MAPK in preimplantation embryos and that insulin might rescue damage of embryos exposed to TNF-$\alpha$.

• Journal of Chest Surgery
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• v.34 no.2
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• pp.138-147
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• 2001

배경: 폐암발생에 EGF의 자가 분비는 암의 성장과정에 직, 간접적인 영향을 주고 있으며, TNF-$\alpha$는 면역 반응의 급성체로서 폐암의 발생을 억제하고 이미 발생한 폐암종의 치료에도 이용되고 있는 실정이다. 폐암 조직과 혈장에서 epidermal growth factor(EGF)와 tumor necrosis factor-$\alpha$(TNF-$\alpha$)를 면역 방사선 분석법을 이용하여 정량분석 하여 발현 정도를 분석해보고자 하였다. 대상 및 방법: 폐암환자 20례와 양성종양 및 육아종 환자 4례에 대해서 AJCCS에 의한 조직학적 분류와 TNM 분류에 따라 구분하여 절제수술을 받은 환자를 대상으로 수술전 혈액을 채취하고 수술직후 적출한 표본을 암이 없는 건강하다고 판단되는 대조조직과 폐암조직에서 일정량의 조직을 절취하여 액화질소 내에 실험시까지 급속 냉동보관 하였다. 수술후 혈액을 재 채취하여 혈장을 분리하여 냉동고에 검사시까지 보관하였다. EGF의 정량은 Human Epidermal Growth Factor kit(Amersham Phamacia Biotech, England)를 사용하였으며, TNF-$\alpha$ 정량은 TNF-$\alpha$ IRMA kit(Biosouce, Belgium)을 사용하여 IRMA 방법으로 각각 정량분석하여 표현유무를 연구한 결과 다음과 같은 결론을 얻었다. 결과: 1. 대조조직, 양성종양 및 육아종과 폐암 수술전후의 조직과 혈청 모두에서 EGF와 TNF-$\alpha$가 발현되었다. 2. EGF와 TNF-$\alpha$의 농도는 대조조직과 양성종양(0.11$\pm$0.06 ng/ml, 20,3$\pm$9.08 pg/ml)에 비하여 폐암조직(0.13$\pm$0.05 ng/ml, 34.34$\pm$47.74pg/ml)에서 유의하게 높은 농도가 발현되고 있었다. 3. 폐암중 선암조직에서 특히 TNF-$\alpha$(80.92$\pm$104.08 ng/ml)의 발현이 강하게 나타났다. 4. 혈청내의 EGF와 TNF-$\alpha$의 발현되는 양이 조직내의 양보다도 높았다. EGF는 5.7배정도 TNF는 1.3배정도 강하게 표현되었다. 5. 폐암의 조직학적 종류에 따라서 EGF는 거의 차이가 없었으나 TNF-$\alpha$ 정량치에는 차이가 있었다. 6. TNM stage가 진행함에 따라 EGF는 농도가 증가하였고 TNF-$\alpha$는 오히려 감소하는 반대되는 교차현상이 있었다. 7. 수술직후 EGF는 증가하였으나 TNF-$\alpha$는 오히려 감소하였다. 결론: 결론적으로 저자는 암조직과 대조조직간에 EGF와 TNF-$\alpha$의 표현량의 차이가 있음을 관찰하였으며 또한 조직과 혈청사이에도 표현량에 차이가 있으며 조직보다도 오히려 혈청내의 농도가 높다는 사실을 관찰하였다. EFG와 TNF-$\alpha$는 정상조직이나 양성조직과 폐암조직 모두에서 분비작용되는 cytokines으로 세포기능에 따라 다양하게 표현이 되며 계속적인 연구로서 밝혀야만 할 과제라고 판단된다.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.45-50
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• 2007

This study investigated biological activity of tumor necrosis factor $(TNF)-\alpha$ secreted from smooth muscle cell (SMC) destined for death by expressing Fas associated death domain containing protein (FADD) (FADD-SMC) when the cells are grown without tetracycline in culture medium. In the absence of tetracycline the FADD-SMC secreted approximately 1000 pg/ml $TNF-\alpha$, whereas hardly detectable amount of the cytokine existed in the presence of tetracycline. The culture medium collected from the FADD-SMC grown in the absence of tetracycline increased phosphorylated form of p38 MAPK and up-regulated nuclear factor kappa B (NF-kB). The medium collected without tetracycline also caused death of L929 cells. Depletion of $TNF-\alpha$ with the soluble TNF receptor (sTNFR) inhibited the phosphorylation of p38 MAPK, the up-regulation of NF-kB activity and the death activity of the medium collected from FADD-SMC in the absence of tetracycline. These results indicate that $TNF-\alpha$ secreted from SMC undergoing death is biologically active and can affect cellular function.

• Environmental Analysis Health and Toxicology
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• v.28
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• pp.12.1-12.5
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• 2013

Objectives The role of genetic polymorphisms of tumor necrosis factor-alpha (TNF-${\alpha}$) for lung cancer development was evaluated. Methods Genotypes of the TNF-${\alpha}$ polymorphisms, -1210C>T, -487A>G, -417A>G, IVS1+123G>A, and IVS3+51A>G, were determined in 616 lung cancer cases and 616 lung cancer-free controls. Results After adjusting for body mass index and smoking, each TNF-${\alpha}$ genotype or haplotype composed of five TNF-${\alpha}$ single nucleotide polymorphisms did not show an association with lung cancer risk (p>0.05). The statistical power was found to be 88.4%, 89.3%, 93.3%, 69.7%, and 93.9% for 1210C>T, -487A>G, -417A>G, IVS1+123G>A, and IVS3+51A>G, respectively. Furthermore, the effects of each SNP or haplotype on lung cancer risk were not found to be different according to the cell type of lung cancer (p>0.05). In the repeated analysis with only subjects without other diseases related to inflammation, there was also no association between polymorphisms or haplotypes of the TNF-${\alpha}$ gene and lung cancer risk (p>0.05). Conclusions This study found no association between common variants of the TNF-${\alpha}$ gene and lung cancer risk.