Overexpression of CCAAT Enhancer-Binding Protein α Inhibits the Growth of K562 Cells via the Foxo3a-Bim Pathway

2016 ◽  
Vol 136 (2) ◽  
pp. 65-70 ◽  
Author(s):  
Guili Zhang ◽  
Fei Dong ◽  
Caifu Luan ◽  
Xia Zhang ◽  
Huiyuan Shao ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Binding Protein ◽  
K562 Cells ◽  
Cell Counting ◽  
Stable Cell Line ◽  
Mrna Levels ◽  
Forkhead Transcription Factor ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Blood Specimens

We aimed to investigate the role of CCAAT enhancer-binding protein α (C/EBPα) in the pathogenesis of chronic myeloid leukemia (CML) and the mechanism underlying its effect. Bone marrow specimens from 50 patients with CML and peripheral blood specimens from 20 healthy individuals were collected. K562 cells were treated with imatinib. Subsequently, a stable cell line, K562-C/EBPα, was constructed. Cell proliferation was assayed with cell counting kit-8, and mRNA levels of C/EBPα, forkhead transcription factor FKHRL1 (Foxo3a) and Bim were detected by semiquantitative PCR. The correlation of C/EBPα and BCR-ABL was assessed by Spearman's correlation analysis. The results showed that C/EBPα mRNA levels were significantly reduced in CML patients compared with healthy subjects (p < 0.001) and were negatively correlated with BCR-ABL1 (r = -0.5046, p < 0.01). Additionally, imatinib enhanced the expression of C/EBPα in K562 cells compared with untreated cells (p < 0.05). Overexpression of C/EBPα significantly decreased cell proliferation and upregulated the expressions of the apoptosis-related genes Foxo3a (p < 0.01) and Bim (p < 0.05) in K562 cells. In conclusion, C/EBPα expression was decreased in patients with CML. Imatinib enhances the expression of C/EBPα in K562 cells, and the overexpression of C/EBPα inhibits cell proliferation and increases apoptosis via the Foxo3a-Bim pathway.

scholarly journals Intestinal maturation in mice lacking CCAAT/enhancer-binding protein α (C/EPBα)

1998 ◽  
Vol 330 (3) ◽  
pp. 1165-1171 ◽  
Author(s):  
J. Thomas OESTERREICHER ◽  
L. Lucy LEEPER ◽  
J. Milton FINEGOLD ◽  
J. Gretchen DARLINGTON ◽  
J. Susan HENNING
Keyword(s):  
Glucose Transporter ◽  
Binding Protein ◽  
Fatty Acid Binding Proteins ◽  
Mrna Levels ◽  
Fatty Acid Binding ◽  
Proliferative Zone ◽  
Glucose Transporter 2 ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Morphological Maturation

In rodents, there is a surge of intestinal expression of CCAAT/enhancer-binding protein α (C/EBPα) in the late fetal phase just before morphological maturation and the onset of expression of numerous epithelial genes. To investigate directly the hypothesis that C/EBPα plays a causal role in the latter phenomena, we have assessed both structural and functional maturation in neonatal intestine from C/EBPα-null mice and their littermates. No effects of C/EBPα genotype were observed on mucosal architecture or on the size of the proliferative zone in the intestinal crypts. Likewise, the mRNA levels for the glucose transporter 2 (GLUT2), intestinal and liver fatty acid-binding proteins, and apolipoprotein A-IV in newborn intestine were similar in all genotypes. Paradoxically, Na+/glucose co-transporter (SGLT1), lactase phlorizin-hydrolase and apolipoprotein B mRNAs were more abundant in the C/EBPα-deficient animals. In wild-type intestines, C/EBPβ and C/EBPΔ mRNAs were detectable throughout the late fetal period and increased toward term in parallel with C/EBPα mRNA. In newborn intestine, there was no compensatory up-regulation of these isoforms in the C/EBPα-deficient mice. We conclude that C/EBPα has no essential role in morphological maturation of the intestine, the pattern of proliferation of the epithelium, or the onset of expression of this cluster of epithelial mRNAs. However, since other C/EBP isoforms are present in the developing intestine, it is possible that there is a generic requirement for a member of the C/EBP family.

scholarly journals Increased Hepatic Cell Proliferation and Lung Abnormalities in Mice Deficient in CCAAT/Enhancer Binding Protein α

1996 ◽  
Vol 271 (40) ◽  
pp. 24753-24760 ◽  
Author(s):  
Per Flodby ◽  
Carrolee Barlow ◽  
Helen Kylefjord ◽  
Lars Åhrlund-Richter ◽  
Kleanthis G. Xanthopoulos
Keyword(s):  
Cell Proliferation ◽  
Binding Protein ◽  
Hepatic Cell ◽  
Enhancer Binding Protein ◽  
Lung Abnormalities ◽  
Ccaat Enhancer Binding Protein

Exchange protein directly activated by cAMP (EPAC) promotes transcriptional activation of the decidual prolactin gene via CCAAT/enhancer-binding protein in human endometrial stromal cells

2018 ◽  
Vol 30 (11) ◽  
pp. 1454
Author(s):  
Kazuya Kusama ◽  
Kazuhiro Tamura ◽  
Hanako Bai ◽  
Toshihiro Sakurai ◽  
Hirotaka Nishi ◽  
...  
Keyword(s):  
Promoter Activity ◽  
Binding Protein ◽  
Luciferase Assay ◽  
Mrna Levels ◽  
Reporter Activity ◽  
Camp Analogue ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Decidual Prolactin ◽  
Exchange Protein

Protein kinase A (PKA) signalling accompanies elevated intracellular cAMP levels during endometrial stromal cell (ESC) decidualisation. Exchange protein directly activated by cAMP (EPAC), an alternate mediator of cAMP signalling, promotes PKA analogue-induced decidualisation; however, the precise mechanism by which EPAC and PKA co-operatively stimulate decidualisation has not been characterised. To examine the role of CCAAT/enhancer-binding protein (C/EBP) in EPAC- and PKA-mediated decidualisation of primary human ESCs, a reporter plasmid containing the 332 bp region upstream from the transcription initiation site of the decidual prolactin (dPRL) gene was generated and the promoter activity was evaluated using a luciferase assay. The dPRL promoter activity was increased by treatment of transfected ESCs with the PKA-selective cAMP analogue N6-phenyl-cAMP (Phe) and enhanced further by co-treatment with the EPAC-selective cAMP analogue 8-(4-chlorophenyltio)-2′-O-methyl cAMP (CPT). Treatment with forskolin, an adenylyl cyclase activator, had a similar effect on reporter activity. Site-directed mutagenesis of the C/EBPβ- and/or C/EBPδ-binding site in the dPRL promoter abolished Phe/CPT-mediated elevation of the reporter activity. EPAC2 knockdown markedly reduced Phe-stimulated C/EBPβ and C/EBPδ mRNA levels, as well as forkhead box O1 (FOXO1) protein levels. These results suggest that EPAC signalling enhances PKA-mediated dPRL expression in ESCs by acting on C/EBP response elements in the promoter region of the gene.

scholarly journals Knockdown of LXRα Inhibits Goat Intramuscular Preadipocyte Differentiation

2018 ◽  
Vol 19 (10) ◽  
pp. 3037 ◽  
Author(s):  
Yan Xiong ◽  
Qing Xu ◽  
Sen Lin ◽  
Yong Wang ◽  
Yaqiu Lin ◽  
...  
Keyword(s):  
Lipid Accumulation ◽  
Early Stage ◽  
Binding Protein ◽  
Regulatory Element ◽  
Adipogenic Differentiation ◽  
Mrna Level ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein

Goat intramuscular fat (IMF) content is mainly determined by the processes of intramuscular preadipocytes adipogenic differentiation and mature adipocyte lipid accumulation. However, the underlying regulators of these biological processes remain largely unknown. Here, we report that the expression of Liver X receptor alpha (LXRα) reaches a peak at early stage and then gradually decreases during goat intramuscular adipogenesis. Knockdown of LXRα mediated by two independent siRNAs significantly inhibits intramuscular adipocytes lipid accumulation and upregulates preadipocytes marker- preadipocyte factor 1 (pref1) expression. Consistently, siRNA treatments robustly decrease mRNA level of adipogenic related genes, including CCAAT enhancer binding protein alpha (Cebpα), Peroxisome proliferator activated receptor gamma (Pparg), Sterol regulatory element binding protein isoform 1c (Srebp1c), Fatty acids binding protein (aP2) and Lipoprotein lipase (Lpl). Next, adenovirus overexpression of LXRα does not affect intramuscular adipocytes adipogenesis manifested by Oil Red O signal measurement and adipogenic specific genes detection. Mechanically, we found that both CCAAT enhancer binding protein beta (Cebpβ) and Kruppel like factor 8 (Klf8) are potential targets of LXRα, indicated by having putative binding sites of LXRα at the promoter of these genes and similar expression pattern during adipogenesis comparing to LXRα. Importantly, mRNA levels of Cebpβ and Klf8 are downregulated significantly in goat LXRα knockdown intramuscular adipocyte. These results demonstrate that loss function of LXRα inhibits intramuscular adipogenesis possibly through down-regulation of Cebpβ and Klf8. Our research will provide new insights into mechanical regulation of goat IMF deposition.

Tumor Suppressor Activity of CCAAT/Enhancer Binding Protein Alpha Is Epigenetically Down-Regulated in Acute Myeloid Leukemia.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2113-2113 ◽  
Author(s):  
Tsung-Chin Lin ◽  
Cheng-Yeh Lee ◽  
Hwei-Fang Tien ◽  
Chung-Yi Hu ◽  
Jih-Luh Tang ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Promoter Region ◽  
Binding Protein ◽  
K562 Cells ◽  
Methylation Pattern ◽  
Upstream Region ◽  
U937 Cells ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Cebpa Mutations

Abstract CCAAT/enhancer binding protein a (C/EBPa) is a 42-kDa transcription factor that is selectively maintained during granulocyte differentiation. Loss of tumor suppressor C/EBPa expression is seen in several human malignancies, including acute myelogenous leukemia (AML). Conditional mouse models revealed that impaired C/EBPa function contributes directly to the development of AML. Previously, we identified CEBPA mutations in 15% patients with AML and sequential study showed the mutations would disappear at complete remission but the same mutations would reappear at relapse. When only considering the AML patients with normal karyotype, CEBPA mutations were identified in up to 35% patients in AML patients. The fusion proteins generated from common chromosome translocation t(8;21), t(15;17), or inv(16) have been reported to down regulate CEBPA expression or to inhibit C/EBPa function. These studies raised the importance of the C/EBPa function, alteration of which would tip the balance from differentiation toward cancer. Since an increasing number of epigenetic deregulation were reported to be associated with AML, we hypothesized that DNA methylation of CEBPA promoter may play roles in modulating expression in AML. In this communication, we showed that C/EBPa were well expressed in HL60 cells, few expressed in U937 cells and poor expressed in K562 cells; real-time RT PCR revealed that the relative RNA expression ratio of HL60, U937, and K562 cells was 673.6, 73.2 and 0.2, respectively. Subsequent DNA sequence analysis revealed that all three cell lines had no CEBPA mutation. Further methylation analysis revealed that the repressed expression in U937 and K562 cells were associated with hypermethylation in the upstream CEBPA promoter region (Figure 1), not the core promoter region (−141 to −15 and −32 to +103). The U937 cells demonstrated methylation pattern in region upstream to CEBPA promoter (−1422 to −1142); whereas K562 cells demonstrated methylation pattern in all three upstream region (−1423 to −1121, −1142 to −896, −918 to −725). These data highlight the significance of CEBPA hypermethylation in AML. In order to evaluate the significance of CEBPA hypermethylation in patients with AML, we studied the methylation status of the CEBPA gene in the bone marrow cells from 92 adult patients with AML at diagnosis using the methylation specific PCR method. Eighteen were M1, 33 M2, 2 M3, and 21 M4. Of these AML patients, 23 (25%) had methylation pattern in region upstream to CEBPA promoter (−1423 to −1121), one further showed methylation pattern in region upstream to CEBPA promoter (−1142 to −896). These results indicate that DNA hypemethylation of upstream CEBPA promoter region, especially from −1423 to −1121, might be involved in the regulation of CEBPA expression and play an important role in AML. Figure 1 Methylation pattern of upstream CEBPA promoter region was shown in U937, HL60 and K562 cells *T-C Lin and C-Y Lee contributed equally to this communication. Figure 1. Methylation pattern of upstream CEBPA promoter region was shown in U937, HL60 and K562 cells *T-C Lin and C-Y Lee contributed equally to this communication.

C/EBPβ (CCAAT/Enhancer Binding Protein) Controls Cell Fate Determination during Mammary Gland Development

2000 ◽  
Vol 14 (3) ◽  
pp. 359-368 ◽  
Author(s):  
Tiffany N. Seagroves ◽  
John P. Lydon ◽  
Russell C. Hovey ◽  
Barbara K. Vonderhaar ◽  
Jeffrey M. Rosen
Keyword(s):  
Mammary Gland ◽  
Cell Fate ◽  
Binding Protein ◽  
Mammary Glands ◽  
Mammary Development ◽  
Mrna Levels ◽  
Wild Type ◽  
Cell Fate Decisions ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein

Abstract Deletion of the transcription factor CCAAT/enhancer binding protein (C/EBP)β results in a severe inhibition of lobuloalveolar development in the mouse mammary gland. Because progesterone receptor (PR) is requisite for alveolar development, the expression of PR was investigated in C/EBPβ−/− mice. Unexpectedly, the number of PR-positive cells, as well as the levels of PR mRNA, were elevated 3-fold in the mammary glands of C/EBPβ−/− mice. Furthermore, in contrast to wild-type nulliparous mice, in which PR distribution shifted from a uniform to nonuniform pattern between 8–12 weeks of age, C/EBPβ−/− mice exhibited uniform PR distribution throughout all stages of mammary development analyzed. No change in C/EBPβ mRNA levels was observed in the mammary glands of PR−/− mice, suggesting that PR acts in a pathway either in parallel to or downstream of C/EBPβ. The overexpression and disrupted cellular distribution of PR in C/EBPβ−/− mice were coincident with a striking 10-fold decrease in cell proliferation after acute steroid hormone treatment, assayed by incorporation of bromodeoxyuridine. In wild-type mice, PR and bromodeoxyuridine-positive cells were adjacent to each other and rarely colocalized. No differences in the level or pattern of PR expression were observed in the uterus, suggesting that C/EBPβ influences PR in a mam-mary-specific fashion. Together, these data suggest that C/EBPβ may control cell fate decisions in the mammary gland through the appropriate temporal and spatial expression of molecular markers, such as PR, that induce the proliferation of alveolar progenitor cells via juxtacrine mechanisms.

The CCAAT/enhancer-binding protein-alpha is expressed in the germinal layer of the growth plate: colocalisation with the growth hormone receptor

1997 ◽  
Vol 155 (3) ◽  
pp. 433-441 ◽  
Author(s):  
NO Vidal ◽  
S Ekberg ◽  
S Enerback ◽  
A Lindahl ◽  
C Ohlsson
Keyword(s):  
Growth Hormone ◽  
Growth Plate ◽  
Binding Protein ◽  
Mrna Levels ◽  
Germinal Layer ◽  
Gh Receptor ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Rat Growth ◽  
Factor C

The transcription factor C/EBP alpha, a member of the CCAAT/enhancer-binding protein family, is highly expressed in the liver and in adipose tissue. The aim of this study was to determine if C/EBP alpha is expressed in rat growth cartilage. The expression pattern of C/EBP alpha in monolayer-cultured growth plate chondrocytes was similar to that of C/EBP alpha during hepatocyte and preadipocyte differentiation. Immunohistochemistry with a polyclonal antibody for C/EBP alpha revealed that the C/EBP alpha protein is present in the perichondrial ring, in the germinal layer of the growth plate and on the surface of the articular cartilage. The growth hormone (GH) receptor has a similar distribution in the rat tibial growth plate, and hypophysectomised rats were used to investigate a possible connection between C/EBP alpha and GH. C/EBP alpha mRNA levels were decreased in rib cartilage after hypophysectomy. However, GH treatment did not counteract this effect, indicating that other pituitary hormones regulate the C/EBP alpha mRNA levels in growth plate cartilage. We thus demonstrate, for the first time, that C/EBP alpha is expressed in cartilage. The finding that C/EBP alpha, like the GH receptor, is predominantly expressed in stem cell areas of the rat growth plate indicates a possible functional role for C/EBP alpha during early chondrogenic differentiation.

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