scholarly journals Lysophosphatidic Acid Triggers Apoptosis in HeLa Cells through the Upregulation of Tumor Necrosis Factor Receptor Superfamily Member 21

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Yunzhou Dong ◽  
Yong Wu ◽  
Mei-Zhen Cui ◽  
Xuemin Xu
Keyword(s):  
Tumor Necrosis Factor ◽  
Lysophosphatidic Acid ◽  
Hela Cells ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Receptor ◽  
Death Receptor ◽  
Dominant Negative ◽  
Lpa Receptor ◽  
Induced Apoptosis ◽  
Necrosis Factor

Lysophosphatidic acid (LPA), a naturally occurring bioactive phospholipid, activates G protein-coupled receptors (GPCRs), leading to regulation of diverse cellular events including cell survival and apoptosis. Despite extensive studies of the signaling pathways that mediate LPA-regulated cell growth and survival, the mechanisms underlying the apoptotic effect of LPA remain largely unclear. In this study, we investigated this issue in HeLa cells. Our data demonstrate that LPA induces apoptosis in HeLa cells at pathologic concentrations with a concomitant upregulation of the expression of TNFRSF21 (tumor necrosis factor receptor superfamily member 21), also known as death receptor number 6 (DR6) involved in inflammation. Moreover, treatment of cells with LPA receptor (LPAR) antagonist abolished the DR6 upregulation by LPA. LPA-induced DR6 expression was also abrogated by pertussis toxin (PTX), an inhibitor of GPCRs, and by inhibitors of PI3K, PKC, MEK, and ERK. Intriguingly, LPA-induced DR6 expression was specifically blocked by dominant-negative form of PKCδ(PKCδ-DN). LPA-induced DR6 expression was also dramatically inhibited by knockdown of ERK or CREB. These results suggest that activation of the MEK/ERK pathway and the transcription factor CREB mediate LPA-induced DR6 expression. More interestingly, knockdown of DR6 using siRNA approach remarkably attenuated LPA-induced apoptosis. In conclusion, our results suggest that LPA-induced apoptosis in HeLa cells is mediated by the upregulation of DR6 expression.

scholarly journals Apparently Normal Tumor Necrosis Factor Receptor 1 Signaling in the Absence of the Silencer of Death Domains

2003 ◽  
Vol 23 (18) ◽  
pp. 6609-6617 ◽  
Author(s):  
Robert Endres ◽  
Georg Häcker ◽  
Inge Brosch ◽  
Klaus Pfeffer
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Receptor ◽  
Death Receptor ◽  
High Dose ◽  
Wild Type ◽  
Induced Apoptosis ◽  
Necrosis Factor

ABSTRACT The silencer of death domains (SODD) has been proposed to prevent constitutive signaling of tumor necrosis factor receptor 1 (TNFR1) in the absence of ligand. Besides TNFR1, death receptor 3 (DR3), Hsp70/Hsc70, and Bcl-2 have been characterized as binding partners of SODD. In order to investigate the in vivo role of SODD, we generated mice congenitally deficient in expression of the sodd gene. No spontaneous inflammatory infiltrations were observed in any organ of these mice. Consistent with this finding, in the absence of SODD no alteration in the activation patterns of nuclear factor κB (NF-κB), stress kinases, or ERK1 or -2 was observed after stimulation with tumor necrosis factor (TNF). Activation of NF-κB by DR3 was also unchanged. The extents of DR3- and TNF-induced apoptosis were comparable in gene-deficient and wild-type cells. Protection of cells against heat shock as mediated by the Hsp70 system and against staurosporine-induced apoptosis was independent of SODD. Furthermore, resistance to high-dose lipopolysaccharide (LPS) injections, LPS-d-GalN injections, and infection with listeriae was similar in wild-type and gene-deficient mice. In conclusion, our data do not support the concept of a unique, nonredundant role of SODD for the functions of TNFR1, Hsp70, and DR3.

scholarly journals Estradiol Abrogates Apoptosis in Breast Cancer Cells through Inactivation of BAD: Ras-dependent Nongenomic Pathways Requiring Signaling through ERK and Akt

2004 ◽  
Vol 15 (7) ◽  
pp. 3266-3284 ◽  
Author(s):  
Romaine Ingrid Fernando ◽  
Jay Wimalasena
Keyword(s):  
Breast Cancer ◽  
Tumor Necrosis Factor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Dominant Negative ◽  
Induced Apoptosis ◽  
Factor Α ◽  
Necrosis Factor

Estrogens such as 17-β estradiol (E2) play a critical role in sporadic breast cancer progression and decrease apoptosis in breast cancer cells. Our studies using estrogen receptor-positive MCF7 cells show that E2 abrogates apoptosis possibly through phosphorylation/inactivation of the proapoptotic protein BAD, which was rapidly phosphorylated at S112 and S136. Inhibition of BAD protein expression with specific antisense oligonucleotides reduced the effectiveness of tumor necrosis factor-α, H2O2, and serum starvation in causing apoptosis. Furthermore, the ability of E2 to prevent tumor necrosis factor-α-induced apoptosis was blocked by overexpression of the BAD S112A/S136A mutant but not the wild-type BAD. BAD S112A/S136A, which lacks phosphorylation sites for p90RSK1 and Akt, was not phosphorylated in response to E2 in vitro. E2 treatment rapidly activated phosphatidylinositol 3-kinase (PI-3K)/Akt and p90RSK1 to an extent similar to insulin-like growth factor-1 treatment. In agreement with p90RSK1 activation, E2 also rapidly activated extracellular signal-regulated kinase, and this activity was down-regulated by chemical and biological inhibition of PI-3K suggestive of cross talk between signaling pathways responding to E2. Dominant negative Ras blocked E2-induced BAD phosphorylation and the Raf-activator RasV12T35S induced BAD phosphorylation as well as enhanced E2-induced phosphorylation at S112. Chemical inhibition of PI-3K and mitogen-activated protein kinase kinase 1 inhibited E2-induced BAD phosphorylation at S112 and S136 and expression of dominant negative Ras-induced apoptosis in proliferating cells. Together, these data demonstrate a new nongenomic mechanism by which E2 prevents apoptosis.

The involvement of oxidative stress in tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in HeLa cells

2002 ◽  
Vol 182 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Myoung Woo Lee ◽  
Soon Cheol Park ◽  
Joung-Hun Kim ◽  
In-Ki Kim ◽  
Kun Soo Han ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Tumor Necrosis Factor ◽  
Hela Cells ◽  
Tumor Necrosis ◽  
Induced Apoptosis ◽  
Necrosis Factor

scholarly journals I-FLICE, a Novel Inhibitor of Tumor Necrosis Factor Receptor-1- and CD-95-induced Apoptosis

1997 ◽  
Vol 272 (28) ◽  
pp. 17255-17257 ◽  
Author(s):  
Shimin Hu ◽  
Claudius Vincenz ◽  
Jian Ni ◽  
Reiner Gentz ◽  
Vishva M. Dixit
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Receptor ◽  
Induced Apoptosis ◽  
Necrosis Factor
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