β-Catenin–dependent lysosomal targeting of internalized tumor necrosis factor-α suppresses caspase-8 activation in apoptosis-resistant colon cancer cells

The Wnt/β-catenin pathway is constitutively activated in more than 90% of human colorectal cancer. Activated β-catenin stimulates cell proliferation and survival, however, its antiapoptotic mechanisms are not fully understood. We show here that activated β-catenin is required to suppress caspase-8 activation, but only in colon cancer cells that are resistant to tumor necrosis factor-α (TNF)-induced apoptosis. We found that lysosomal delivery of internalized TNF occurred at a faster pace in apoptosis-resistant than in apoptosis-sensitive colon cancer cells. Retardation of endosomal trafficking through vacuolar ATPase (V-ATPase) inhibition enhanced caspase-8 activation in apoptosis-resistant but not apoptosis-sensitive cells. Interestingly, knockdown of β-catenin also prolonged TNF association with the early endosome and enhanced caspase-8 activation in apoptosis-resistant but not apoptosis-sensitive colon cancer cells. In a mouse model of inflammation-associated colon tumors, we found nuclear expression of β-catenin, resistance to TNF-induced apoptosis, and reactivation of apoptosis in vivo after cotreatment of TNF with a V-ATPase inhibitor. Together these results suggest that activated β-catenin can facilitate endosomal trafficking of internalized TNF to suppress caspase-8 activation in colon cancer cells.

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Novel Piperazine-based Compounds Inhibit Microtubule Dynamics and Sensitize Colon Cancer Cells to Tumor Necrosis Factor-induced Apoptosis

Journal of Biological Chemistry ◽

10.1074/jbc.m113.499319 ◽

2013 ◽

Vol 289 (5) ◽

pp. 2978-2991 ◽

Cited By ~ 27

Author(s):

Avijeet Chopra ◽

Amy Anderson ◽

Charles Giardina

Keyword(s):

Colon Cancer ◽

Tumor Necrosis Factor ◽

Cancer Cells ◽

Tumor Necrosis ◽

Microtubule Dynamics ◽

Colon Cancer Cells ◽

Induced Apoptosis ◽

Necrosis Factor

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

Molecular Biology of the Cell ◽

10.1091/mbc.e03-11-0823 ◽

2004 ◽

Vol 15 (7) ◽

pp. 3266-3284 ◽

Cited By ~ 87

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.

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Contrasting Effects of IG20 and Its Splice Isoforms, MADD and DENN-SV, on Tumor Necrosis Factor α-induced Apoptosis and Activation of Caspase-8 and -3

Journal of Biological Chemistry ◽

10.1074/jbc.m104835200 ◽

2001 ◽

Vol 276 (50) ◽

pp. 47202-47211 ◽

Cited By ~ 40

Author(s):

Adeeb M. Al-Zoubi ◽

Elena V. Efimova ◽

Shashi Kaithamana ◽

Osvaldo Martinez ◽

Mohammed El-Azami El-Idrissi ◽

...

Keyword(s):

Alternative Splicing ◽

Tumor Necrosis Factor ◽

Tumor Necrosis ◽

Tumor Necrosis Factor Α ◽

Single Gene ◽

Caspase 8 ◽

Tnf Α ◽

Induced Apoptosis ◽

Factor Α ◽

Necrosis Factor

We identified a novel cDNA (IG20) that is homologous to cDNAs encoding a proteindifferentiallyexpressed innormal andneoplastic cells (DENN-SV) and human MADD (MAPK-activatingdeathdomain-containing protein). Furthermore, we show that the above variants most likely result from alternative splicing of a single gene. Functional analyses of these variants in permanently transfected HeLa cells revealed that IG20 and DENN-SV render them more susceptible or resistant to tumor necrosis factor α (TNF-α)-induced apoptosis, respectively. All variants tested could interact with TNF receptor 1 and activate ERK and nuclear factor κB. However, relative to control cells, only cells expressing IG20 showed enhanced TNF-α-induced activation of caspase-8 and -3, whereas cells expressing DENN-SV showed either reduced or no caspase activation. Transfection of these cells with a cDNA encoding CrmA maximally inhibited apoptosis in HeLa-IG20 cells. Our results show that IG20 can promote TNF-α-induced apoptosis and activation of caspase-8 and -3 and suggest that it may play a novel role in the regulation of the pleiotropic effects of TNF-α through alternative splicing.

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