scholarly journals Transforming Growth Factor-β1 (TGF-β)–induced Apoptosis of Prostate Cancer Cells Involves Smad7-dependent Activation of p38 by TGF-β-activated Kinase 1 and Mitogen-activated Protein Kinase Kinase 3

2003 ◽  
Vol 14 (2) ◽  
pp. 529-544 ◽  
Author(s):  
Sofia Edlund ◽  
Shizhong Bu ◽  
Norbert Schuster ◽  
Pontus Aspenström ◽  
Rainer Heuchel ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Protein Kinase ◽  
Transforming Growth Factor ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Mitogen Activated Protein ◽  
Induced Apoptosis ◽  
Tgf Β1 ◽  
Protein Kinase Kinase

The inhibitory Smad7, a direct target gene for transforming growth factor-β (TGF-β), mediates TGF-β1–induced apoptosis in several cell types. Herein, we report that apoptosis of human prostate cancer PC-3U cells induced by TGF-β1 or Smad7 overexpression is caused by a specific activation of the p38 mitogen-activated protein kinase pathway in a TGF-β–activated kinase 1 (TAK1)- and mitogen-activated protein kinase kinase 3 (MKK3)-dependent manner. Expression of dominant negative p38, dominant negative MKK3, or incubation with the p38 selective inhibitor [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole], prevented TGF-β1–induced apoptosis. The expression of Smad7 was required for TGF-β–induced activation of MKK3 and p38 kinases, and endogenous Smad7 was found to interact with phosphorylated p38 in a ligand-dependent manner. Ectopic expression of wild-type TAK1 promoted TGF-β1–induced phosphorylation of p38 and apoptosis, whereas dominant negative TAK1 reduced TGF-β1–induced phosphorylation of p38 and apoptosis. Endogenous Smad7 was found to interact with TAK1, and TAK1, MKK3, and p38 were coimmunoprecipitated with Smad7 in transiently transfected COS1 cells. Moreover, ectopically expressed Smad7 enhanced the coimmunoprecipitation of HA-MKK3 and Flag-p38, supporting the notion that Smad7 may act as a scaffolding protein and facilitate TAK1- and MKK3-mediated activation of p38.

scholarly journals Coordinate Regulation of IκB Kinases by Mitogen-Activated Protein Kinase Kinase Kinase 1 and NF-κB-Inducing Kinase

1998 ◽  
Vol 18 (12) ◽  
pp. 7336-7343 ◽  
Author(s):  
Shino Nemoto ◽  
Joseph A. DiDonato ◽  
Anning Lin
Keyword(s):  
Protein Kinase ◽  
Interleukin 1 ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Dominant Negative Mutant ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Ikk Complex ◽  
Mitogen Activated Protein ◽  
Protein Kinase Kinase

ABSTRACT IκB kinases (IKKα and IKKβ) are key components of the IKK complex that mediates activation of the transcription factor NF-κB in response to extracellular stimuli such as inflammatory cytokines, viral and bacterial infection, and UV irradiation. Although NF-κB-inducing kinase (NIK) interacts with and activates the IKKs, the upstream kinases for the IKKs still remain obscure. We identified mitogen-activated protein kinase kinase kinase 1 (MEKK1) as an immediate upstream kinase of the IKK complex. MEKK1 is activated by tumor necrosis factor alpha (TNF-α) and interleukin-1 and can potentiate the stimulatory effect of TNF-α on IKK and NF-κB activation. The dominant negative mutant of MEKK1, on the other hand, partially blocks activation of IKK by TNF-α. MEKK1 interacts with and stimulates the activities of both IKKα and IKKβ in transfected HeLa and COS-1 cells and directly phosphorylates the IKKs in vitro. Furthermore, MEKK1 appears to act in parallel to NIK, leading to synergistic activation of the IKK complex. The formation of the MEKK1-IKK complex versus the NIK-IKK complex may provide a molecular basis for regulation of the IKK complex by various extracellular signals.

Cyclic stretch induces proliferation and TGF-β1-mediated apoptosis via p38 and ERK in ureteric bud cells

2010 ◽  
Vol 299 (3) ◽  
pp. F648-F655 ◽  
Author(s):  
Hisayo Fujita ◽  
Mariko Hida ◽  
Katsuyoshi Kanemoto ◽  
Keiichi Fukuda ◽  
Michio Nagata ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Urinary Tract Obstruction ◽  
Obstructive Uropathy ◽  
Cyclic Stretch ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Ureteric Bud ◽  
Induced Apoptosis ◽  
Pax2 Expression ◽  
Tgf Β1

We previously reported that p38 mitogen-activated protein kinase (p38) and phosphorylated ERK are upregulated in cyst epithelium of human renal dysplasia and obstructive uropathy in fetal lambs (Omori S, Fukuzawa R, Hida M, Awazu M. Kidney Int 61: 899–906, 2002; Omori S, Kitagawa H, Koike J, Fujita H, Hida M, Pringle KC, Awazu M. Kidney Int 73: 1031–1037, 2008). Dysplastic epithelium is characterized by proliferation, apoptosis, and upregulation of Pax2 and transforming growth factor (TGF)-β1. In the present study, we investigated whether cyclic mechanical stretching of ureteric bud cells, a mimic of the hydrodynamic derangement after fetal urinary tract obstruction, reproduces events seen in vivo. Cyclic stretch activated p38 and ERK and upregulated Pax2 expression in a time-dependent manner in ureteric bud cells. Stretch-stimulated Pax2 expression was suppressed by a p38 inhibitor, SB203580, or a MEK inhibitor, PD98059. 5-Deoxyuridine incorporation was increased by stretch at 24 h, which was also abolished by SB203580 or PD98059. On the other hand, apoptosis was not induced at 24 h by stretch but was significantly increased at 48 h. TGF-β1 secretion was increased by stretch at 24 h, which was inhibited by SB203580 or PD98059. Inhibition of p38 or ERK as well as anti-TGF-β antibody abolished the stretch-induced apoptosis. Finally, exogenous TGF-β1 induced apoptosis of ureteric bud cells, which was inhibited by SB203580 and PD98059. In conclusion, cyclic stretch induces Pax2 upregulation, proliferation, and TGF-β1-mediated apoptosis, features characteristic of dysplastic epithelium, via p38 and ERK in ureteric bud cells.

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