scholarly journals Cancer cells activate p53 in response to 10-formyltetrahydrofolate dehydrogenase expression

2005 ◽  
Vol 391 (3) ◽  
pp. 503-511 ◽  
Author(s):  
Natalia V. Oleinik ◽  
Natalia I. Krupenko ◽  
David G. Priest ◽  
Sergey A. Krupenko
Keyword(s):  
Cancer Cells ◽  
Ectopic Expression ◽  
A549 Cells ◽  
Dominant Negative ◽  
G1 Arrest ◽  
Transactivation Domain ◽  
Downstream Target ◽  
Formyltetrahydrofolate Dehydrogenase ◽  
Induced Apoptosis ◽  
Hct116 Cells

A folate enzyme, FDH (10-formyltetrahydrofolate dehydrogenase; EC 1.5.1.6), is not a typical tumour suppressor, but it has two basic characteristics of one, i.e. it is down-regulated in tumours and its expression is selectively cytotoxic to cancer cells. We have recently shown that ectopic expression of FDH in A549 lung cancer cells induces G1 arrest and apoptosis that was accompanied by elevation of p53 and its downstream target, p21. It was not known, however, whether FDH-induced apoptosis is p53-dependent or not. In the present study, we report that FDH-induced suppressor effects are strictly p53-dependent in A549 cells. Both knockdown of p53 using an RNAi (RNA interference) approach and disabling of p53 function by dominant-negative inhibition with R175H mutant p53 prevented FDH-induced cytotoxicity in these cells. Ablation of the FDH-suppressor effect is associated with an inability to activate apoptosis in the absence of functional p53. We have also shown that FDH elevation results in p53 phosphorylation at Ser-6 and Ser-20 in the p53 transactivation domain, and Ser-392 in the C-terminal domain, but only Ser-6 is strictly required to mediate FDH effects. Also, translocation of p53 to the nuclei and expression of the pro-apoptotic protein PUMA (Bcl2 binding component 3) was observed after induction of FDH expression. Elevation of FDH in p53 functional HCT116 cells induced strong growth inhibition, while growth of p53-deficient HCT116 cells was unaffected. This implies that activation of p53-dependent pathways is a general downstream mechanism in response to induction of FDH expression in p53 functional cancer cells.

Depletion of death-associated protein-3 induces chemoresistance in gastric cancer cells through the β-catenin/LGR5/Bcl-2 axis

2019 ◽  
Vol 67 (5) ◽  
pp. 856-861 ◽  
Author(s):  
Yongning Jia ◽  
Ziyu Li ◽  
Xiaojing Cheng ◽  
Xiaojiang Wu ◽  
Fei Pang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Protein Kinase ◽  
Cancer Cells ◽  
Ectopic Expression ◽  
Nuclear Accumulation ◽  
Apoptosis Resistance ◽  
Gastric Cancer Cells ◽  
Downstream Target ◽  
Novel Strategy ◽  
Induced Apoptosis

Previously, we demonstrated that death-associated protein-3 (DAP3) loss drives chemoresistance in gastric cancer cells. In the present study, we aimed to determine the underlying molecular mechanism. The effect of DAP3 silencing on β-catenin signaling was assessed. The direct mediator of DAP3 silencing-induced chemoresistance was identified. Depletion of DAP3 stimulates nuclear accumulation of β-catenin and enhances β-catenin-dependent transcriptional activity in gastric cancer cells. However, the protein kinase B , , extracellular regulated protein kinase and signal transducer and activator of transcription 3 signaling pathways remain unaffected by DAP3 loss. We found that the downstream target gene LGR5 (leucine-rich G-protein coupled receptor 5) is upregulated in DAP3-depleted gastric cancer cells. Moreover, knockdown of LGR5 resensitizes DAP3-depleted gastric cancer cells to 5-fluorouracil (5-FU) and oxaliplatin. We also observed that ectopic expression of LGR5 reduces apoptosis in gastric cancer cells on treatment with 5-FU and oxaliplatin, which is accompanied by prevention of caspase-3 cleavage. The antiapoptotic protein Bcl-2 is identified as a key mediator of LGR5-induced apoptosis resistance in gastric cancer cells. The present findings indicate that DAP3 deficiency-induced chemoresistance in gastric cancer is at least partially mediated through the β-catenin/LGR5/Bcl-2 axis. Targeting LGR5 may provide a novel strategy to overcome chemoresistance in DAP3-deficient gastric cancer cells.

IK1 channel activity contributes to cisplatin sensitivity of human epidermoid cancer cells

2008 ◽  
Vol 294 (6) ◽  
pp. C1398-C1406 ◽  
Author(s):  
Elbert L. Lee ◽  
Yuichi Hasegawa ◽  
Takahiro Shimizu ◽  
Yasunobu Okada
Keyword(s):  
Cancer Cells ◽  
Cellular Response ◽  
Physiological Role ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Dominant Negative ◽  
Cation Channels ◽  
Channel Activity ◽  
Kb Cells ◽  
Induced Apoptosis

Cisplatin, a platinum-based drug, is an important weapon against many types of cancer. It induces apoptosis by forming adducts with DNA, although many aspects of its mechanism of action remain to be clarified. Previously, we found a role for the volume-sensitive, outwardly rectifying Cl− channel in cisplatin-induced apoptosis. To investigate the possibility that cation channels also have a role in the cellular response to cisplatin, we examined the activity of cation channels in cisplatin-sensitive KB-3-1 (KB) epidermoid cancer cells by the whole cell patch-clamp method. A cation channel in KB cells, activated by hypotonic stress, was identified as the Ca2+-activated, intermediate-conductance K+ (IK1) channel on the basis of its requirement for intracellular Ca2+, its blockage by the blockers clotrimazole and triarylmethane-34, and its suppression by a dominant-negative construct. Activity of this channel was not observed in KCP-4 cells, a cisplatin-resistant cell line derived from KB cells, and its molecular expression, observed by semiquantitative RT-PCR and immunostaining, appeared much reduced. Cell volume measurements confirmed a physiological role for the IK1 channel as a component of the volume-regulatory machinery in KB cells. A possible role of the IK1 channel in cisplatin-induced apoptosis was investigated. It was found that clotrimazole and triarylmethane-34 inhibited a cisplatin-induced decrease in cell viability and increase in caspase-3/7 activity, whereas 1-ethyl-2-benzimidazolinone, an activator of the channel, had the opposite effect. Thus IK1 channel activity appears to mediate, at least in part, the response of KB cells to cisplatin treatment.

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.

scholarly journals Increased Expression of Death Receptors 4 and 5 Synergizes the Apoptosis Response to Combined Treatment with Etoposide and TRAIL

2000 ◽  
Vol 20 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Spencer B. Gibson ◽  
Ryan Oyer ◽  
Aaron C. Spalding ◽  
Steven M. Anderson ◽  
Gary L. Johnson
Keyword(s):  
Epithelial Cell ◽  
Cancer Cells ◽  
Topoisomerase Ii ◽  
Combined Treatment ◽  
Death Receptor ◽  
Death Receptors ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Death Receptor Ligand ◽  
Induced Apoptosis

ABSTRACT Chemotherapeutic genotoxins induce apoptosis in epithelial-cell-derived cancer cells. The death receptor ligand TRAIL also induces apoptosis in epithelial-cell-derived cancer cells but generally fails to induce apoptosis in nontransformed cells. We show here that the treatment of four different epithelial cell lines with the topoisomerase II inhibitor etoposide in combination with TRAIL (tumor necrosis factor [TNF]-related apoptosis-inducing ligand) induces a synergistic apoptotic response. The mechanism of the synergistic effect results from the etoposide-mediated increase in the expression of the death receptors 4 (DR4) and 5 (DR5). Inhibition of NF-κB activation by expression of kinase-inactive MEK kinase 1(MEKK1) or dominant-negative IκB (ΔIκB) blocked the increase in DR4 and DR5 expression following etoposide treatment. Addition of a soluble decoy DR4 fusion protein (DR4:Fc) to cell cultures reduced the amount of etoposide-induced apoptosis in a dose-dependent manner. The addition of a soluble TNF decoy receptor (TNFR:Fc) was without effect, demonstrating the specificity of DR4 binding ligands in the etoposide-induced apoptosis response. Thus, genotoxin treatment in combination with TRAIL is an effective inducer of epithelial-cell-derived tumor cell apoptosis relative to either treatment alone.

scholarly journals The Death Domain Kinase RIP Is Essential for TRAIL (Apo2L)-Induced Activation of IκB Kinase and c-Jun N-Terminal Kinase

2000 ◽  
Vol 20 (18) ◽  
pp. 6638-6645 ◽  
Author(s):  
Yong Lin ◽  
Anne Devin ◽  
Amy Cook ◽  
Maccon M. Keane ◽  
Michelle Kelliher ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Death Domain ◽  
Iκb Kinase ◽  
Tnf Superfamily ◽  
Key Factor ◽  
Induced Apoptosis ◽  
Jnk Activation ◽  
Necrosis Factor

ABSTRACT Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) (Apo2 ligand [Apo2L]) is a member of the TNF superfamily and has been shown to have selective antitumor activity. Although it is known that TRAIL (Apo2L) induces apoptosis and activates NF-κB and Jun N-terminal kinase (JNK) through receptors such as TRAIL-R1 (DR4) and TRAIL-R2 (DR5), the components of its signaling cascade have not been well defined. In this report, we demonstrated that the death domain kinase RIP is essential for TRAIL-induced IκB kinase (IKK) and JNK activation. We found that ectopic expression of the dominant negative mutant RIP, RIP(559–671), blocks TRAIL-induced IKK and JNK activation. In the RIP null fibroblasts, TRAIL failed to activate IKK and only partially activated JNK. The endogenous RIP protein was detected by immunoprecipitation in the TRAIL-R1 complex after TRAIL treatment. More importantly, we found that RIP is not involved in TRAIL-induced apoptosis. In addition, we also demonstrated that the TNF receptor-associated factor 2 (TRAF2) plays little role in TRAIL-induced IKK activation although it is required for TRAIL-mediated JNK activation. These results indicated that the death domain kinase RIP, a key factor in TNF signaling, also plays a pivotal role in TRAIL-induced IKK and JNK activation.

scholarly journals αvβ3 integrin expression up-regulates cdc2, which modulates cell migration

2003 ◽  
Vol 161 (4) ◽  
pp. 817-826 ◽  
Author(s):  
Thomas Manes ◽  
Duo-Qi Zheng ◽  
Simona Tognin ◽  
Amy S. Woodard ◽  
Pier Carlo Marchisio ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cancer Cells ◽  
Intracellular Signaling ◽  
Ectopic Expression ◽  
Cell Types ◽  
Dominant Negative ◽  
Αvβ3 Integrin ◽  
Activity Levels ◽  
Mrna Levels ◽  
Downstream Effector

The αvβ3 integrin has been shown to promote cell migration through activation of intracellular signaling pathways. We describe here a novel pathway that modulates cell migration and that is activated by αvβ3 and, as downstream effector, by cdc2 (cdk1). We report that αvβ3 expression in LNCaP (β3-LNCaP) prostate cancer cells causes increased cdc2 mRNA levels as evaluated by gene expression analysis, and increased cdc2 protein and kinase activity levels. We provide three lines of evidence that increased levels of cdc2 contribute to a motile phenotype on integrin ligands in different cell types. First, increased levels of cdc2 correlate with more motile phenotypes of cancer cells. Second, ectopic expression of cdc2 increases cell migration, whereas expression of dominant-negative cdc2 inhibits migration. Third, cdc2 inhibitors reduce cell migration without affecting cell adhesion. We also show that cdc2 increases cell migration via specific association with cyclin B2, and we unravel a novel pathway of cell motility that involves, downstream of cdc2, caldesmon. cdc2 and caldesmon are shown here to localize in membrane ruffles in motile cells. These results show that cdc2 is a downstream effector of the αvβ3 integrin, and that it promotes cell migration.

scholarly journals Loss of the tumor suppressor BTG3 drives a pro-angiogenic tumor microenvironment through HIF-1 activation

2020 ◽  
Vol 11 (12) ◽  
Author(s):  
Yu-Che Cheng ◽  
Hsin-Yi Chiang ◽  
Shang-Jung Cheng ◽  
Hung-Wei Chang ◽  
Yi-Ju Li ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Ectopic Expression ◽  
Matrix Remodeling ◽  
Transactivation Domain ◽  
Promoting Effect ◽  
Expression Ratio ◽  
Downstream Target ◽  
Tumor Growth And Metastasis

AbstractB-cell translocation gene 3 (BTG3) is a member of the antiproliferative BTG gene family and is a downstream target of p53. Here, we show that senescence triggered by BTG3 depletion was accompanied by a secretome enriched with cytokines, growth factors, and matrix-remodeling enzymes, which could promote angiogenesis and cell scattering in vitro. We present evidence that at least part of these activities can be explained by elevated HIF-1α activity. Mechanistically, the BTG3 C-terminal domain competes with the coactivator p300 for binding the HIF-1α transactivation domain. The angiogenic promoting effect of BTG3 knockdown was largely diminished upon co-depletion of HIF-1α, indicating that HIF-1α is a major downstream target of BTG3 in the control of angiogenesis. In vivo, ectopic expression of BTG3 suppresses angiogenesis in xenograft tumors; and syngenic tumor growth and metastasis were enhanced in Btg3-null mice. Moreover, analysis of clinical datasets revealed that a higher BTG3/VEGFA expression ratio correlates with improved patient survival in a number of cancer types. Taken together, our findings highlight the non-autonomous regulation of tumor microenvironment by BTG3 while suppressing tumor progression.

scholarly journals Androgen and Its Receptor Promote Bax-Mediated Apoptosis

2006 ◽  
Vol 26 (5) ◽  
pp. 1908-1916 ◽  
Author(s):  
Yuting Lin ◽  
John Kokontis ◽  
Fangming Tang ◽  
Bradley Godfrey ◽  
Shutsung Liao ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Ectopic Expression ◽  
Transcription Activation ◽  
Prostate Cancer Cells ◽  
Small Interference Rna ◽  
Apoptotic Death ◽  
Apoptosis Inhibition ◽  
Induced Apoptosis ◽  
Interference Rna

ABSTRACT Androgen and its receptor (AR) have been reported to have pro- or antiapoptotic functions. However, the underlying molecular mechanism is incompletely understood. We report here that androgen and AR promote Bax-mediated apoptosis in prostate cancer cells. UV irradiation and ectopic expression of Bax induce apoptosis in AR-positive, but not AR-negative prostate cancer cells. UV- and Bax-induced apoptosis is abrogated in AR-positive cells that express small interference RNA (siRNA) of AR and is sensitized by reintroduction of AR into AR-negative cells. Although AR is able to promote Bax-mediated apoptosis independently of androgen, the promotion by AR can be further potentiated by androgen via AR-dependent transcription activation. AR is essential for the translocation of Bax to mitochondria in UV- or Bax-induced apoptosis. Inhibition of Bax expression by Bax siRNA suppresses UV-induced apoptosis in AR-positive cells. In addition, introduction of AR into AR-negative prostate cancer cells upregulates expression levels of the BH3-only protein Noxa, whereas inhibition of Noxa expression reduces the promotion by AR on UV-induced apoptosis. Thus, our results reveal a novel cross talk between the androgen/AR hormonal signaling pathway and the intrinsic apoptotic death pathway that determines the sensitivity of stress-induced apoptosis in prostate cancer cells.

scholarly journals c-Myb is an essential downstream target for homeobox-mediated transformation of hematopoietic cells

Blood ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 297-304 ◽  
Author(s):  
Jay L. Hess ◽  
Claudia B. Bittner ◽  
Deniz T. Zeisig ◽  
Christian Bach ◽  
Uta Fuchs ◽  
...  
Keyword(s):  
Ectopic Expression ◽  
Hematopoietic Cells ◽  
Dominant Negative ◽  
Rt Pcr ◽  
Short Term ◽  
Downstream Target ◽  
Hoxa Genes ◽  
Polymerase Chain ◽  
Differentiation Block ◽  
Sirna Target

Abdominal-type HoxA genes in combination with Meis1 are well-documented on-cogenes in various leukemias but it is unclear how they exert their transforming function. Here we used a system of conditional transformation by an inducible mixed lineage leukemia-eleven-nineteen leukemia (MLL-ENL) oncoprotein to overexpress Hoxa9 and Meis1 in primary hematopoietic cells. Arrays identified c-Myb and a c-Myb target (Gstm1) among the genes with the strongest response to Hoxa9/Meis1. c-Myb overexpression was verified by Northern blot and quantitative reverse transcription-polymerase chain reaction (RT-PCR). Also MLL-ENL activated c-Myb through up-regulation of Hoxa9 and Meis1. Consequently, short-term suppression of c-Myb by small inhibitory RNA (siRNA) efficiently inhibited transformation by MLL-ENL but did not impair transformation by transcription factor E2A-hepatic leukemia factor (E2A-HLF). The anti c-Myb siRNA effect was abrogated by coexpression of a c-Myb derivative with a mutated siRNA target site. The introduction of a dominant-negative c-Myb mutant had a similar but weaker effect on MLL-ENL-mediated transformation. Hematopoietic precursors from mice homozygous for a hypo-morphic c-Myb allele were more severely affected and could be transformed neither by MLL-ENL nor by E2A-HLF. Ectopic expression of c-Myb induced a differentiation block but c-Myb alone was not transforming in a replating assay similar to Hoxa9/Meis1. These results suggest that c-Myb is essential but not sufficient for Hoxa9/Meis1 mediated transformation. (Blood. 2006;108:297-304)

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