scholarly journals E2F-1:DP-1 induces p53 and overrides survival factors to trigger apoptosis.

1995 ◽  
Vol 15 (12) ◽  
pp. 6864-6874 ◽  
Author(s):  
S W Hiebert ◽  
G Packham ◽  
D K Strom ◽  
R Haffner ◽  
M Oren ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Binding Activity ◽  
Functional Link ◽  
Cycle Progression ◽  
Survival Factors ◽  
Dna Binding Activity ◽  
Induce Cell Cycle Progression ◽  
Induced Apoptosis ◽  
Related Proteins ◽  
E2f Proteins

The E2F DNA binding activity consists of a heterodimer between E2F and DP family proteins, and these interactions are required for association of E2F proteins with pRb and the pRb-related proteins p107 and p130, which modulate E2F transcriptional activities. E2F-1 expression is sufficient to release fibroblasts from G0 and induce entry into S phase, yet it also initiates apoptosis. To investigate the mechanisms of E2F-induced apoptosis, we utilized interleukin-3 (IL-3)-dependent 32D.3 myeloid cells, a model of hematopoietic progenitor programmed cell death. In the absence of IL-3, E2F-1 alone was sufficient to induce apoptosis, and p53 levels were diminished. DP-1 alone was not sufficient to induce cell cycle progression or alter rates of death following IL-3 withdrawal. However, overexpression of both E2F-1 and DP-1 led to the rapid death of cells even in the presence of survival factors. In the presence of IL-3, levels of endogenous wild-type p53 increased in response to E2F-1, and coexpression of DP-1 further augmented p53 levels. These results provide evidence that E2F is a functional link between the tumor suppressors p53 and pRb. However, induction of p53 alone was not sufficient to trigger apoptosis, suggesting that the ability of E2F to override survival factors involves additional effectors.

scholarly journals Phosphorylation Controls Ikaros's Ability To Negatively Regulate the G1-S Transition

2004 ◽  
Vol 24 (7) ◽  
pp. 2797-2807 ◽  
Author(s):  
Pablo Gómez-del Arco ◽  
Kazushige Maki ◽  
Katia Georgopoulos
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Cell Cycle Progression ◽  
Rapid Development ◽  
Binding Activity ◽  
Casein Kinase ◽  
Cycle Progression ◽  
Dna Binding Activity ◽  
Increased Activity ◽  
Inactivating Mutations

ABSTRACT Ikaros is a key regulator of lymphocyte proliferative responses. Inactivating mutations in Ikaros cause antigen-mediated lymphocyte hyperproliferation and the rapid development of leukemia and lymphoma. Here we show that Ikaros's ability to negatively regulate the G1-S transition can be modulated by phosphorylation of a serine/threonine-rich conserved region (p1) in exon 8. Ikaros phosphorylation in p1 is induced during the G1-S transition. Mutations that prevent phosphorylation in p1 increase Ikaros's ability to impede cell cycle progression and its affinity for DNA. Casein kinase II, whose increased activity in lymphocytes leads to transformation, is a key player in Ikaros p1 phosphorylation. We thus propose that Ikaros's activity as a regulator of the G1-S transition is controlled by phosphorylation in response to signaling events that downmodulate its DNA binding activity.

scholarly journals Retinoblastoma Protein Enhances the Fidelity of Chromosome Segregation Mediated by hsHec1p

2000 ◽  
Vol 20 (10) ◽  
pp. 3529-3537 ◽  
Author(s):  
Lei Zheng ◽  
Yumay Chen ◽  
Daniel J. Riley ◽  
Phang-Lang Chen ◽  
Wen-Hwa Lee
Keyword(s):  
Dna Binding ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Retinoblastoma Protein ◽  
Binding Activity ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Cycle Progression ◽  
Dna Binding Activity ◽  
M Phase

ABSTRACT Retinoblastoma protein (Rb) plays important roles in cell cycle progression and cellular differentiation. It may also participate in M phase events, although heretofore only circumstantial evidence has suggested such involvement. Here we show that Rb interacts, through an IxCxE motif and specifically during G2/M phase, with hsHec1p, a protein essential for proper chromosome segregation. The interaction between Rb and hsHec1p was reconstituted in a yeast strain in which human hsHEC1 rescues the null mutation of scHEC1. Expression of Rb reduced chromosome segregation errors fivefold in yeast cells sustained by a temperature-sensitive (ts) hshec1-113 allele and enhanced the ability of wild-type hsHec1p to suppress lethality caused by a ts smc1mutation. The interaction between Hec1p and Smc1p was important for the specific DNA-binding activity of Smc1p. Expression of Rb restored part of the inactivated function of hshec1-113p and thereby increased the DNA-binding activity of Smc1p. Rb thus increased the fidelity of chromosome segregation mediated by hsHec1p in a heterologous yeast system.

scholarly journals Serum induction of MEF2/RSRF expression in vascular myocytes is mediated at the level of translation.

1995 ◽  
Vol 15 (6) ◽  
pp. 3415-3423 ◽  
Author(s):  
E Suzuki ◽  
K Guo ◽  
M Kolman ◽  
Y T Yu ◽  
K Walsh
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Smooth Muscle ◽  
Dna Binding ◽  
Cell Cycle Progression ◽  
Vascular Tissue ◽  
Binding Activity ◽  
Cycle Progression ◽  
Dna Binding Activity ◽  
Vascular Myocytes

Vascular smooth muscle cells (VSMCs) reversibly coordinate the expression of VSMC-specific genes and the genes required for cell cycle progression. Here we demonstrate that isoforms of the MEF2/RSRF transcription factor are expressed in VSMCs and in vascular tissue. The MEF2A DNA-binding activity was upregulated when quiescent VSMCs were stimulated to proliferate with serum mitogens. The serum-induction of MEF2A DNA-binding activity occurred approximately 4 h following serum activation, and this correlated with an increase in the level of MEF2A protein without changes in the level of MEF2A mRNA or protein stability. These results indicate that MEF2A induction by serum is regulated at the level of translation.

scholarly journals Suppression of E1A-Mediated Transformation by the p50E4F Transcription Factor

1999 ◽  
Vol 19 (7) ◽  
pp. 4739-4749 ◽  
Author(s):  
Elma R. Fernandes ◽  
Robert J. Rooney
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Suppressive Effect ◽  
Culture Conditions ◽  
Binding Activity ◽  
Cellular Transcription Factor ◽  
Dna Binding Activity ◽  
3T3 Fibroblasts ◽  
Induced Apoptosis ◽  
Nih 3T3

ABSTRACT The adenovirus E1A gene can act as an oncogene or a tumor suppressor, with the latter effect generally arising from the induction of apoptosis or the repression of genes that provide oncogenic growth stimuli (e.g., HER-2/c-erbB2/neu) or increased metastatic invasiveness (e.g., metalloproteases). In this study, coexpression of E1A and p50E4F, a cellular transcription factor whose DNA binding activity is stimulated by E1A, suppressed colony formation by NIH 3T3 cells and transformation of primary rat embryo fibroblasts but had no observed effect in the absence of E1A. Domains in p50E4F required for stimulation of the adenovirus E4 promoter were required for the suppressive effect, indicating a transcriptional mechanism. In serum-containing media, retroviral expression of p50E4F in E1A13S/ras-transformed NIH 3T3 fibroblasts had little effect on subconfluent cultures but accelerated a decline in viability after the cultures reached confluence. Cell death occurred by both apoptosis and necrosis, with the predominance of each process determined by culture conditions. In serum-free media, p50E4F accelerated E1A-induced apoptosis. The results suggest that p50E4F sensitizes cells to signals or conditions that cause cell death.

scholarly journals Cyclin E and Bcl-xL cooperatively induce cell cycle progression in c-Rel−/− B cells

Oncogene ◽  
2003 ◽  
Vol 22 (52) ◽  
pp. 8472-8486 ◽  
Author(s):  
Shuhua Cheng ◽  
Constance Yu Hsia ◽  
Gustavo Leone ◽  
Hsiou-Chi Liou
Keyword(s):  
Cell Cycle ◽  
B Cells ◽  
Cell Cycle Progression ◽  
Cyclin E ◽  
Cycle Progression ◽  
Induce Cell Cycle Progression

scholarly journals Effect of Butyrate on Collagen Expression, Cell Viability, Cell Cycle Progression and Related Proteins Expression of MG-63 Osteoblastic Cells

PLoS ONE ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. e0165438 ◽  
Author(s):  
Mei-Chi Chang ◽  
Yi-Ling Tsai ◽  
Eric Jein-Wein Liou ◽  
Chia-Mei Tang ◽  
Tong-Mei Wang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Viability ◽  
Cell Cycle Progression ◽  
Osteoblastic Cells ◽  
Cycle Progression ◽  
Collagen Expression ◽  
Related Proteins

2-Deoxy-d-ribose-Induced Apoptosis in HL-60 Cells Is Associated with the Cell Cycle Progression by Spermidine

1999 ◽  
Vol 257 (2) ◽  
pp. 460-465 ◽  
Author(s):  
Maria Giuseppina Monti ◽  
Stefania Ghiaroni ◽  
Daniela Barbieri ◽  
Claudio Franceschi ◽  
Gaetano Marverti ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Induced Apoptosis

Evaluation of GPER agonist G-1 combined with navitoclax in platinum-resistant and -sensitive ovarian cancer cells.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e13563-e13563
Author(s):  
Dennis C. DeSimone ◽  
Trung T. Nguyen ◽  
Eugen Brailiou ◽  
John C. Taylor ◽  
Gabriela Cristina Brailoiu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Ovarian Cancer ◽  
Cancer Cells ◽  
Cell Cycle Progression ◽  
Parp Cleavage ◽  
Ovarian Cancer Cells ◽  
Cycle Progression ◽  
Platinum Based Chemotherapy ◽  
Induced Apoptosis ◽  
In Cells

e13563 Background: Most ovarian cancer patients are treated with platinum-based chemotherapy but eventually relapse with incurable disease. The G protein-coupled estrogen receptor GPER (GPR30) mediates Ca2+ mobilization in response to estrogen and G-1, a synthetic agonist. Large and sustained Ca2+ responses can lead to mitochondrial Ca2+ overload and apoptosis. Hence, we evaluated whether G-1 could induce apoptosis in cisplatin-sensitive A2780 and isogenic cisplatin–resistant CP70 (14-fold resistant), C30 (70-fold resistant) and C200 (157-fold resistant) human ovarian cancer cells. Bcl-2 and Bcl-xL protect mitochondria from Ca2+overload, and were overexpressed in these cisplatin-resistant cells; thus we also examined combining the Bcl-2 family inhibitor navitoclax with G-1. Methods: Cytoplasmic [Ca2+]c and mitochondrial [Ca2+]m were monitored using microscopy and fluorescent Ca2+ probes. Cell cycle, apoptosis and mitochondrial membrane potential (MMP) were assessed by flow cytometry of propidium iodide, Annexin V and DiIC1(5) -stained cells. The intracellular Ca2+ chelator BAPTA was used to block Ca2+mobilization. Results: Expression of the 53kDa GPER but not the 38 kDa isoform progressively increased with increasing cisplatin resistance. G-1 elicited sustained [Ca2+]c rises that correlated with 53 kDa GPER expression, followed by rises in [Ca2+]m. In all cells, 2.5 μM G-1 blocked cell cycle progression at G2/M, inhibited proliferation, and induced apoptosis (A2780 > C30 > CP70 ≥ C200). G-1 induced p53, caspase-3 and PARP cleavage, and MMP loss. BAPTA prevented G-1’s cell cycle and apoptotic effects in cells showing large Ca2+ mobilization responses but did not in cells with small Ca2+responses. Combining navitoclax with G-1 superadditively decreased cell viability and increased apoptosis. Conclusions: G-1 blocked cell cycle progression and induced apoptosis via a Ca2+-dependent pathway in cells expressing high 53 kDa GPER levels, but via a Ca2+-independent pathway in cells with low 53 kDa GPER expression. G-1 also interacted cooperatively with naviticlax. Therefore, G-1 plus navitoclax shows potential for therapeutic use in platinum-sensitive and -resistant ovarian cancer.

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