scholarly journals Differential Roles for Cyclin-Dependent Kinase Inhibitors p21 and p16 in the Mechanisms of Senescence and Differentiation in Human Fibroblasts

1999 ◽  
Vol 19 (3) ◽  
pp. 2109-2117 ◽  
Author(s):  
Gretchen H. Stein ◽  
Linda F. Drullinger ◽  
Alexandre Soulard ◽  
Vjekoslav Dulić
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Early Stage ◽  
Cyclin E ◽  
Human Fibroblasts ◽  
Senescent Cell ◽  
Nuclear Antigen ◽  
Cyclin Dependent Kinase ◽  
Cycle Arrest

ABSTRACT The irreversible G1 arrest in senescent human diploid fibroblasts is probably caused by inactivation of the G1cyclin–cyclin-dependent kinase (Cdk) complexes responsible for phosphorylation of the retinoblastoma protein (pRb). We show that the Cdk inhibitor p21Sdi1,Cip1,Waf1, which accumulates progressively in aging cells, binds to and inactivates all cyclin E-Cdk2 complexes in senescent cells, whereas in young cells only p21-free Cdk2 complexes are active. Furthermore, the senescent-cell-cycle arrest occurs prior to the accumulation of the Cdk4-Cdk6 inhibitor p16Ink4a, suggesting that p21 may be sufficient for this event. Accordingly, cyclin D1-associated phosphorylation of pRb at Ser-780 is lacking even in newly senescent fibroblasts that have a low amount of p16. Instead, the cyclin D1-Cdk4 and cyclin D1-Cdk6 complexes in these cells are associated with an increased amount of p21, suggesting that p21 may be responsible for inactivation of both cyclin E- and cyclin D1-associated kinase activity at the early stage of senescence. Moreover, even in the late stage of senescence when p16 is high, cyclin D1-Cdk4 complexes are persistent, albeit reduced by ≤50% compared to young cells. We also provide new evidence that p21 may play a role in inactivation of the DNA replication factor proliferating cell nuclear antigen during early senescence. Finally, because p16 accumulates in parallel with the increases in senescence-associated β-Gal activity and cell volume that characterize the senescent phenotype, we suggest that p16 upregulation may be part of a differentiation program that is turned on in senescent cells. Since p21 decreases after senescence is achieved, this upregulation of p16 may be essential for maintenance of the senescent-cell-cycle arrest.

scholarly journals Aberrant Expression of Cyclin D1 in Cancer

2015 ◽  
Vol 4 ◽  
pp. STI.S30306 ◽  
Author(s):  
Kazushi Inoue ◽  
Elizabeth A. Fry
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Biological Activities ◽  
Cyclin E ◽  
Arginine Methylation ◽  
Cyclin D ◽  
Aberrant Expression ◽  
Cycle Arrest

Cyclin D1 binds and activates cyclin-dependent kinases 4/6 (Cdk4/6) to phosphorylate the retinoblastoma (RB) family proteins, relieving E2F/DPs from the negative restraint of RB proteins and histone deacetylases (HDACs). The cyclin D-Cdk4/6 complexes activate cyclin E/Cdk2 through titration of the Cdk inhibitors p21Cip1/p27Kip1. Cyclin E/Cdk2 further phosphorylates RBs, thereby activating E2F/DPs, and cells enter the S-phase of the cell cycle. Cyclin D-Cdk4/6 also phosphorylates MEP50 subunit of the protein arginine methyltransferase 5 (PRMT5), which cooperates with cyclin D1 to drive lymphomagenesis in vivo. Activated PRMPT5 causes arginine methylation of p53 to suppress expression of proapoptotic and antiproliferative target genes, explaining the molecular mechanism for tumorigenesis. Cyclin D1 physically interacts with transcription factors such as estrogen receptor, androgen receptor, and Myb family proteins to regulate gene expression in Cdk-independent fashion. Dmp1 is a Myb-like protein that quenches the oncogenic signals from activated Ras or HER2 by inducing Arf/p53-dependent cell cycle arrest. Cyclin D1 binds to Dmp1 to activate both Arf and Ink4a promoters to induce cell cycle arrest or apoptosis in non-transformed cells to prevent them from neoplastic transformation. Dmp1deficiency significantly accelerates mouse mammary tumorigenesis with reduced apoptosis and increased metastasis. Cyclin D1 interferes with ligand activation of PPARγ involved in cellular differentiation; it also physically interacts with HDACs and p300 to repress gene expression. It has also been shown that cyclin D1 accelerates tumorigenesis through transcriptional activation of miR-17/20 and Dicer1 which, in turn, represses cyclin D1 expression. Identification of cyclin D1-binding proteins/promoters will be essential for further clarification of its biological activities.

scholarly journals Raf-induced proliferation or cell cycle arrest is determined by the level of Raf activity with arrest mediated by p21Cip1.

1997 ◽  
Vol 17 (9) ◽  
pp. 5598-5611 ◽  
Author(s):  
D Woods ◽  
D Parry ◽  
H Cherwinski ◽  
E Bosch ◽  
E Lees ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cyclin E ◽  
G1 Arrest ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Primary Mouse

The Raf family of protein kinases display differences in their abilities to promote the entry of quiescent NIH 3T3 cells into the S phase of the cell cycle. Although conditional activation of deltaA-Raf:ER promoted cell cycle progression, activation of deltaRaf-1:ER and deltaB-Raf:ER elicited a G1 arrest that was not overcome by exogenously added growth factors. Activation of all three deltaRaf:ER kinases led to elevated expression of cyclin D1 and cyclin E and reduced expression of p27Kip1. However, activation of deltaB-Raf:ER and deltaRaf-1:ER induced the expression of p21Cip1, whereas activation of deltaA-Raf:ER did not. A catalytically potentiated form of deltaA-Raf:ER, generated by point mutation, strongly induced p21Cip1 expression and elicited cell cycle arrest similarly to deltaB-Raf:ER and deltaRaf-1:ER. These data suggested that the strength and duration of signaling by Raf kinases might influence the biological outcome of activation of this pathway. By titration of deltaB-Raf:ER activity we demonstrated that low levels of Raf activity led to activation of cyclin D1-cdk4 and cyclin E-cdk2 complexes and to cell cycle progression whereas higher Raf activity elicited cell cycle arrest correlating with p21Cip1 induction and inhibition of cyclin-cdk activity. Using green fluorescent protein-tagged forms of deltaRaf-1:ER in primary mouse embryo fibroblasts (MEFs) we demonstrated that p21Cip1 was induced by Raf in a p53-independent manner, leading to cell cycle arrest. By contrast, activation of Raf in p21Cip1(-/-) MEFs led to a robust mitogenic response that was similar to that observed in response to platelet-derived growth factor. These data indicate that, depending on the level of kinase activity, Raf can elicit either cell cycle progression or cell cycle arrest in mouse fibroblasts. The ability of Raf to elicit cell cycle arrest is strongly associated with its ability to induce the expression of the cyclin-dependent kinase inhibitor p21Cip1 in a manner that bears analogy to alpha-factor arrest in Saccharomyces cerevisiae. These data are consistent with a role for Raf kinases in both proliferation and differentiation of mammalian cells.

scholarly journals SOX7 is involved in polyphyllin D-induced G0/G1 cell cycle arrest through down-regulation of cyclin D1

2020 ◽  
Vol 70 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Bin Zheng ◽  
Gang Wang ◽  
Wenbo Gao ◽  
Qiquan Wu ◽  
Weizhi Zhu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Complete Medium ◽  
Dependent Manner ◽  
Cyclin Dependent Kinase ◽  
Down Regulation ◽  
Cycle Arrest ◽  
G1 Cell Cycle Arrest ◽  
Polyphyllin D

AbstractThe incidence of mortality of prostate cancer (PCa) has been an uptrend in recent years. Our previous study showed that the sex-determining region Y-box 7 (SOX7) was low-expressed and served as a tumor suppressor in PCa cells. Here, we describe the effects of polyphyllin D (PD) on proliferation and cell cycle modifications of PCa cells, and whether SOX7 participates in this process. PC-3 cells were cultured in complete medium containing PD for 12, 24, and 48 h. MTT assay was used to investigate the cytotoxic effects of PD. Cell cycle progression was analyzed using propidium iodide (PI) staining, and protein levels were assayed by Western blot analysis. Our results showed low expression of SOX7 in PCa tissues/cells compared to their non-tumorous counterparts/RWPE-1 cells. Moreover, PD inhibited the proliferation of PC-3 cells in a dose- and time-dependent manner. PD induced G0/G1 cell cycle arrest, while co-treatment with short interfering RNA targeting SOX7 (siSOX7) had reversed this effect. PD downregulated SOX7, cyclin D1, cyclin-dependent kinase 4 (CDK4), and cyclin-dependent kinase 6 (CDK6) expressions in a dose-dependent manner, whereas co-treatment of siSOX7 and PD rescued the PD-inhibited cyclin D1 expression. However, no obvious changes were observed in CDK4 or CDK6 expression. These results indicate that SOX7 is involved in PD-induced PC-3 cell cycle arrest through down-regulation of cyclin D1.

Phenylpropanoid-based sulfonamide promotes cyclin D1 and cyclin E down-regulation and induces cell cycle arrest at G1/S transition in estrogen positive MCF-7 cell line

2019 ◽  
Vol 59 ◽  
pp. 150-160 ◽  
Author(s):  
Helloana Azevedo-Barbosa ◽  
Guilherme Álvaro Ferreira-Silva ◽  
Carolina Faria Silva ◽  
Thiago Belarmino de Souza ◽  
Danielle Ferreira Dias ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Cell Line ◽  
Cyclin E ◽  
Down Regulation ◽  
Cycle Arrest ◽  
Mcf 7

scholarly journals Quantitative Model of Cell Cycle Arrest and Cellular Senescence in Primary Human Fibroblasts

PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e42150 ◽  
Author(s):  
Sascha Schäuble ◽  
Karolin Klement ◽  
Shiva Marthandan ◽  
Sandra Münch ◽  
Ines Heiland ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cellular Senescence ◽  
Human Fibroblasts ◽  
Quantitative Model ◽  
Cycle Arrest
Sign in / Sign up

Export Citation Format

Share Document