The Interplay Between Microrna-223 and E2F1 Regulates Cell Cycle Control During Granulopoiesis.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 255-255
Author(s):  
John Anto Pulikkan ◽  
Viola Dengler ◽  
Philomina Sona Peramangalam ◽  
Abdul A. Peer Zada ◽  
Carsten Müller tidow ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Chromatin Immunoprecipitation ◽  
Cell Cycle Progression ◽  
Conflicts Of Interest ◽  
Myeloid Cells ◽  
Granulocytic Differentiation ◽  
Cycle Progression ◽  
Protein Levels ◽  
Cell Cycle Inhibition

Abstract Abstract 255 Transcription factor CCAAT enhancer binding protein α (C/EBPα) functions as a master regulator of granulocyte development by co-ordinating cell cycle inhibition and differentiation. Recent findings demonstrate that deregulation of C/EBPα is a critical step in the development of acute myeloid leukemia (AML). Inhibition of E2F1, the key regulator of cell cycle progression by C/EBPα is essential for granulopoiesis and disruption of this function of C/EBPα leads to leukemia. The mechanism with which C/EBPα inhibits E2F1 in granulopoiesis is poorly understood. Recent advances in our understanding about microRNAs suggest that these molecules have profound impact in gene expression programmes. Also, deregulation of microRNAs has been shown as a hall mark of many cancers including leukemia. microRNA-223 (miR-223) is upregulated by C/EBPα during granulopoiesis. The pivotal role of miR-223 in granulopoiesis is shown by the finding that mice deficient for miR-223 display defects in granulopoiesis. In this study, we explored the role of miR-223 in the cell cycle inhibition function of C/EBPα. Computational analysis by using programmes such as Target Scan suggests that E2F1 is a putative target of miR-223. Luciferase assays using 3'UTR of E2F1 suggest E2F1 is a potential target of miR-223. Western blot analysis using bone marrow cells isolated from miR-223 null mice shows accumulation of E2F1 protein levels. Interestingly, E2F1 protein levels were downregulated during miR-223 overexpression in myeloid cells. Analysis of miR-223 by quantitative Real-Time RT-PCR in AML patient samples shows that miR-223 is downregulated in different subtypes of AML. Proliferation assays, cell cycle analysis and BrdU assays show that miR-223 functions as an inhibitor of myeloid cell cycle progression. Several studies have reported the ability of E2F1 to block granulocytic differentiation. We next analysed whether E2F1 is inhibiting myeloid differentiation through miR-223. Promoter assays show that E2F1 inhibits the miR-223 promoter activity. By using Chromatin immunoprecipitation assays, we found that E2F1 binds to miR-223 promoter in leukemia derived cell lines and this binding is reversed during granulocytic differentiation. We also observed that E2F1 is bound to the miR-223 promoter in blast cells isolated from AML patients as analysed by chromatin immunoprecipitation assays. In addition, we show that overexpression of E2F1 leads to down regulation of miR-223 levels in myeloid cells. All these data suggest that E2F1 functions as a transcriptional repressor of the miR-223 gene. Taken together, our data suggest that granulopoiesis is regulated by the interplay between miR-223 and E2F1 and deregulation of this interplay may lead to the development of AML. Overexpression of miR-223 could be a potential strategy in the treatment of AML patients in which E2F1 inhibition by C/EBPα is deregulated. Disclosures: No relevant conflicts of interest to declare.

scholarly journals USP48 Governs Cell Cycle Progression by Regulating the Protein Level of Aurora B

2021 ◽  
Vol 22 (16) ◽  
pp. 8508
Author(s):  
Ainsley Mike Antao ◽  
Kamini Kaushal ◽  
Soumyadip Das ◽  
Vijai Singh ◽  
Bharathi Suresh ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Aurora B ◽  
Deubiquitinating Enzymes ◽  
Cycle Progression ◽  
Protein Levels ◽  
Steady State Levels ◽  
Cycle Regulation ◽  
Normal Cell Cycle

Deubiquitinating enzymes play key roles in the precise modulation of Aurora B—an essential cell cycle regulator. The expression of Aurora B increases before the onset of mitosis and decreases during mitotic exit; an imbalance in these levels has a severe impact on the fate of the cell cycle. Dysregulation of Aurora B can lead to aberrant chromosomal segregation and accumulation of errors during mitosis, eventually resulting in cytokinesis failure. Thus, it is essential to identify the precise regulatory mechanisms that modulate Aurora B levels during the cell division cycle. Using a deubiquitinase knockout strategy, we identified USP48 as an important candidate that can regulate Aurora B protein levels during the normal cell cycle. Here, we report that USP48 interacts with and stabilizes the Aurora B protein. Furthermore, we showed that the deubiquitinating activity of USP48 helps to maintain the steady-state levels of Aurora B protein by regulating its half-life. Finally, USP48 knockout resulted in delayed progression of cell cycle due to accumulation of mitotic defects and ultimately cytokinesis failure, suggesting the role of USP48 in cell cycle regulation.

Enforced expression of CUL-4A interferes with granulocytic differentiation and exit from the cell cycle

Blood ◽  
2003 ◽  
Vol 101 (5) ◽  
pp. 1769-1776 ◽  
Author(s):  
Binghui Li ◽  
Feng-Chun Yang ◽  
D. Wade Clapp ◽  
Kristin T. Chun
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Regulatory Function ◽  
Cell Cycle Distribution ◽  
Cell Cycle Regulators ◽  
Granulocytic Differentiation ◽  
Cycle Progression ◽  
Protein Levels ◽  
Cycle Regulation ◽  
Normal Controls

The cullin family of proteins is involved in the ubiquitin-mediated degradation of cell cycle regulators. Relatively little is known about the function of the CUL-4A cullin, but its overexpression in breast cancer suggests CUL-4A might also regulate the cell cycle. In addition, since other cullins are required for normal development, we hypothesized that CUL-4A is involved in regulating cell cycle progression during differentiation. We observed that CUL-4A mRNA and protein levels decline 2.5-fold during the differentiation of PLB-985 myeloid cells into granulocytes. To examine the significance of this observation, we overexpressedCUL-4A in these cells and found that modest (< 2-fold), enforced expression of CUL-4A attenuates terminal granulocytic differentiation and instead promotes proliferation. This overexpression similarly affects the differentiation of these cells into macrophages. We recently reported that nearly one half of CUL-4A+/− mice are nonviable, and in this report, we show that the viable heterozygous mice, which have reducedCUL-4A expression, have dramatically fewer erythroid and multipotential progenitors than normal controls. Together these results indicate that appropriate CUL-4A expression is essential for embryonic development and for cell cycle regulation during granulocytic differentiation and suggest this gene plays a broader role in hematopoiesis. Since enforced CUL-4A expression does not alter the cell cycle distribution of uninduced cells but dramatically increases the proportion of induced cells that remains in S-phase and reduces the proportion that accumulates in G0/G1, our results show that thisCUL-4A regulatory function is interconnected with differentiation, a novel finding for mammalian cullins.

scholarly journals A Circular RNA from the MDM2 Locus Controls Cell Cycle Progression by Suppressing p53 Levels

2020 ◽  
Vol 40 (9) ◽  
Author(s):  
Ritu Chaudhary ◽  
Bruna R. Muys ◽  
Ioannis Grammatikakis ◽  
Supriyo De ◽  
Kotb Abdelmohsen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
P53 Protein ◽  
Circular Rnas ◽  
Small Interfering Rnas ◽  
Cycle Progression ◽  
Protein Levels

ABSTRACT Circular RNAs (circRNAs) are a class of noncoding RNAs produced by a noncanonical form of alternative splicing called back-splicing. To investigate a potential role of circRNAs in the p53 pathway, we analyzed RNA sequencing (RNA-seq) data from colorectal cancer cell lines (HCT116, RKO, and SW48) that were untreated or treated with a DNA-damaging agent. Surprisingly, unlike the strong p53-dependent induction of hundreds of p53-induced mRNAs upon DNA damage, only a few circRNAs were upregulated from p53-induced genes. circ-MDM2, an annotated circRNA from the MDM2 locus, was one of the handful of circRNAs that originated from a p53-induced gene. Given the central role of MDM2 in suppressing p53 protein levels and p53 activity, we investigated the function of circ-MDM2. Knocking down circ-MDM2 with small interfering RNAs (siRNAs) that targeted circ-MDM2 did not alter MDM2 mRNA or MDM2 protein levels but resulted in increased basal p53 levels and growth defects in vitro and in vivo. Consistent with these results, transcriptome profiling showed increased expression of several direct p53 targets, reduced retinoblastoma protein (Rb) phosphorylation, and defects in G1-S progression upon silencing circ-MDM2. Our results on the initial characterization of circ-MDM2 identify a new player from the MDM2 locus that suppresses p53 levels and cell cycle progression.

PTTG has a Dual Role of Promotion-Inhibition in the Development of Pituitary Adenomas

2019 ◽  
Vol 26 (11) ◽  
pp. 800-818
Author(s):  
Zujian Xiong ◽  
Xuejun Li ◽  
Qi Yang
Keyword(s):  
Cell Cycle ◽  
Pituitary Adenoma ◽  
Pituitary Adenomas ◽  
Cell Cycle Progression ◽  
Key Factors ◽  
Cycle Progression ◽  
Sister Chromatids ◽  
Regulation Of Cell Cycle ◽  
Late Stages

Pituitary Tumor Transforming Gene (PTTG) of human is known as a checkpoint gene in the middle and late stages of mitosis, and is also a proto-oncogene that promotes cell cycle progression. In the nucleus, PTTG works as securin in controlling the mid-term segregation of sister chromatids. Overexpression of PTTG, entering the nucleus with the help of PBF in pituitary adenomas, participates in the regulation of cell cycle, interferes with DNA repair, induces genetic instability, transactivates FGF-2 and VEGF and promotes angiogenesis and tumor invasion. Simultaneously, overexpression of PTTG induces tumor cell senescence through the DNA damage pathway, making pituitary adenoma possessing the potential self-limiting ability. To elucidate the mechanism of PTTG in the regulation of pituitary adenomas, we focus on both the positive and negative function of PTTG and find out key factors interacted with PTTG in pituitary adenomas. Furthermore, we discuss other possible mechanisms correlate with PTTG in pituitary adenoma initiation and development and the potential value of PTTG in clinical treatment.

scholarly journals Phosphorylation of RCC1 on Serine 11 Facilitates G1/S Transition in HPV E7-Expressing Cells

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 995
Author(s):  
Xiaoyan Hou ◽  
Lijun Qiao ◽  
Ruijuan Liu ◽  
Xuechao Han ◽  
Weifang Zhang
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Mtor Pathway ◽  
Cycle Progression ◽  
Post Translational Modifications ◽  
Hpv E7 ◽  
Cycle Regulation

Persistent infection of high-risk human papillomavirus (HR-HPV) plays a causal role in cervical cancer. Regulator of chromosome condensation 1 (RCC1) is a critical cell cycle regulator, which undergoes a few post-translational modifications including phosphorylation. Here, we showed that serine 11 (S11) of RCC1 was phosphorylated in HPV E7-expressing cells. However, S11 phosphorylation was not up-regulated by CDK1 in E7-expressing cells; instead, the PI3K/AKT/mTOR pathway promoted S11 phosphorylation. Knockdown of AKT or inhibition of the PI3K/AKT/mTOR pathway down-regulated phosphorylation of RCC1 S11. Furthermore, S11 phosphorylation occurred throughout the cell cycle, and reached its peak during the mitosis phase. Our previous data proved that RCC1 was necessary for the G1/S cell cycle progression, and in the present study we showed that the RCC1 mutant, in which S11 was mutated to alanine (S11A) to mimic non-phosphorylation status, lost the ability to facilitate G1/S transition in E7-expressing cells. Moreover, RCC1 S11 was phosphorylated by the PI3K/AKT/mTOR pathway in HPV-positive cervical cancer SiHa and HeLa cells. We conclude that S11 of RCC1 is phosphorylated by the PI3K/AKT/mTOR pathway and phosphorylation of RCC1 S11 facilitates the abrogation of G1 checkpoint in HPV E7-expressing cells. In short, our study explores a new role of RCC1 S11 phosphorylation in cell cycle regulation.

scholarly journals EGFR-ERK induced activation of GRHL1 promotes cell cycle progression by up-regulating cell cycle related genes in lung cancer

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Yiming He ◽  
Mingxi Gan ◽  
Yanan Wang ◽  
Tong Huang ◽  
Jianbin Wang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Potential Role ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Phosphorylation Site ◽  
Promoter Regions ◽  
Cycle Progression

AbstractGrainyhead-like 1 (GRHL1) is a transcription factor involved in embryonic development. However, little is known about the biological functions of GRHL1 in cancer. In this study, we found that GRHL1 was upregulated in non-small cell lung cancer (NSCLC) and correlated with poor survival of patients. GRHL1 overexpression promoted the proliferation of NSCLC cells and knocking down GRHL1 inhibited the proliferation. RNA sequencing showed that a series of cell cycle-related genes were altered when knocking down GRHL1. We further demonstrated that GRHL1 could regulate the expression of cell cycle-related genes by binding to the promoter regions and increasing the transcription of the target genes. Besides, we also found that EGF stimulation could activate GRHL1 and promoted its nuclear translocation. We identified the key phosphorylation site at Ser76 on GRHL1 that is regulated by the EGFR-ERK axis. Taken together, these findings elucidate a new function of GRHL1 on regulating the cell cycle progression and point out the potential role of GRHL1 as a drug target in NSCLC.

Mutations at sites involved in Suc1 binding inactivate Cdc2

1991 ◽  
Vol 11 (12) ◽  
pp. 6177-6184
Author(s):  
B Ducommun ◽  
P Brambilla ◽  
G Draetta
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Specific Interaction ◽  
Physiological Role ◽  
Negative Effects ◽  
Alanine Scanning Mutagenesis ◽  
Cycle Progression ◽  
Mutant Proteins ◽  
Additional Protein

suc1+ encodes an essential cell cycle regulator of the fission yeast Schizosaccharomyces pombe. Its product, a 13-kDa protein, interacts with the Cdc2 protein kinase. Both positive and negative effects on cell cycle progression have been attributed to Suc1. To date, the exact mechanisms and the physiological role of the interaction between Suc1 and Cdc2 remain unclear. Here we have studied the molecular basis of this association. We show that Cdc2 can bind Suc1 or its mammalian homolog directly in the absence of any additional protein component. Using an alanine scanning mutagenesis method, we analyzed the interaction between Cdc2 and Suc1. We show that the integrity of several domains on the Cdc2 protein, including sites directly involved in catalytic activity, is required for binding to Suc1. Furthermore, Cdc2 mutant proteins unable to bind Suc1 (but able to bind cyclins) are nonfunctional when overexpressed in S. pombe, indicating that a specific interaction with Suc1 is required for Cdc2 function.

scholarly journals Evidence for a role of spindle matrix formation in cell cycle progression by antibody perturbation

PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0208022 ◽  
Author(s):  
Changfu Yao ◽  
Chao Wang ◽  
Yeran Li ◽  
Michael Zavortink ◽  
Vincent Archambault ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Spindle Matrix

scholarly journals Role of AKT/mTORC1 pathway in pancreatic β-cell proliferation

2012 ◽  
pp. 235-243 ◽  
Author(s):  
Norman Balcazar Morales ◽  
Cecilia Aguilar de Plata
Keyword(s):  
Cell Cycle ◽  
Growth Factors ◽  
Cell Cycle Progression ◽  
Cell Mass ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Cycle Progression ◽  
Mtorc1 Signaling

Growth factors, insulin signaling and nutrients are important regulators of β-cell mass and function. The events linking these signals to regulation of β-cell mass are not completely understood. Recent findings indicate that mTOR pathway integrates signals from growth factors and nutrients with transcription, translation, cell size, cytoskeleton remodeling and mitochondrial metabolism. mTOR is a part of two distinct complexes; mTORC1 and mTORC2. The mammalian TORC1 is sensitive to rapamycin and contains Raptor, deptor, PRAS40 and the G protein β-subunit-like protein (GβL). mTORC1 activates key regulators of protein translation; ribosomal S6 kinase (S6K) and eukaryote initiation factor 4E-binding protein 1. This review summarizes current findings about the role of AKT/mTORC1 signaling in regulation of pancreatic β cell mass and proliferation. mTORC1 is a major regulator of β-cell cycle progression by modulation of cyclins D2, D3 and cdk4/cyclin D activity. These studies uncovered key novel pathways controlling cell cycle progression in β-cells in vivo. This information can be used to develop alternative approaches to expand β-cell mass in vivo and in vitro without the risk of oncogenic transformation. The acquisition of such knowledge is critical for the design of improved therapeutic strategies for the treatment and cure of diabetes as well as to understand the effects of mTOR inhibitors in β-cell function.

Sign in / Sign up

Export Citation Format

Share Document