scholarly journals Regulation of the expression of cyclin-dependent kinase inhibitor p21 by E2A and Id proteins.

1997 ◽  
Vol 17 (10) ◽  
pp. 5888-5896 ◽  
Author(s):  
S Prabhu ◽  
A Ignatova ◽  
S T Park ◽  
X H Sun
Keyword(s):  
Cell Growth ◽  
Kinase Inhibitor ◽  
Control Cell ◽  
Luciferase Reporter ◽  
Cyclin Dependent Kinase ◽  
3T3 Cells ◽  
Cyclin Dependent Kinase Inhibitor ◽  
Id Proteins ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

The helix-loop-helix transcription factor E2A plays important roles not only in promoting cellular differentiation but also in suppressing cell growth. Id proteins, the inhibitors of E2A, have opposite effects on cell differentiation and growth. To understand the mechanisms by which E2A suppresses cell growth, we examined the role of E2A in regulating the expression of the cyclin-dependent kinase inhibitor p21CIP1/WAF1/SD11, which prevents cell cycle progression upon overexpression. By using transient-cotransfection assays of luciferase reporter constructs in HeLa cells, we have found that overexpression of E2A can transcriptionally activate the p21 gene. To identify the sequences that mediate this activation in the promoter of the p21 gene, we carried out mutational analyses. Out of the eight putative E2A-binding sequences (E1 to E8) in the promoter, the E1 to E3 sequences located close to the transcription start site are found to be essential. In addition, loss of the E boxes in the promoter also reduces p21 expression without cotransfection with E2A in HIT pancreatic cells, where the endogenous E2A-like activity is high. Furthermore, we have also shown that overexpression of E2A in 293T cells activates expression of the endogenous p21 gene at both the levels of mRNA and protein. In correlation with the finding that E47 overexpression leads to growth arrest in NIH 3T3 cells, we have shown that Id1 overexpression in NIH 3T3 cells accelerates cell growth and inhibits p21 expression. Taken together, these results provide insight into the mechanisms by which E2A and Id proteins control cell growth.

scholarly journals Transactivation of Platelet-Derived Growth Factor Receptor α by the GTPase-Deficient Activated Mutant of Gα12

2006 ◽  
Vol 26 (1) ◽  
pp. 50-62 ◽  
Author(s):  
Rashmi N. Kumar ◽  
Ji Hee Ha ◽  
Rangasudhagar Radhakrishnan ◽  
Danny N. Dhanasekaran
Keyword(s):  
Growth Factor ◽  
Cell Growth ◽  
Signaling Pathway ◽  
Growth Factor Receptor ◽  
Platelet Derived Growth Factor ◽  
Dominant Negative Mutant ◽  
Dependent Manner ◽  
3T3 Cells ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

ABSTRACT The GTPase-deficient, activated mutant of Gα12 (Gα12Q229L, or Gα12QL) induces neoplastic growth and oncogenic transformation of NIH 3T3 cells. Using microarray analysis, we have previously identified a role for platelet-derived growth factor receptor α (PDGFRα) in Gα12-mediated cell growth (R. N. Kumar et al., Cell Biochem. Biophys. 41:63-73, 2004). In the present study, we report that Gα12QL stimulates the functional expression of PDGFRα and demonstrate that the expression of PDGFRα by Gα12QL is dependent on the small GTPase Rho. Our results indicate that it is cell type independent as the transient expression of Gα12QL or the activation of Gα12-coupled receptors stimulates the expression of PDGFRα in NIH 3T3 as well as in human astrocytoma 1321N1 cells. Furthermore, we demonstrate the presence of an autocrine loop involving PDGF-A and PDGFRα in Gα12QL-transformed cells. Analysis of the functional consequences of the Gα12-PDGFRα signaling axis indicates that Gα12 stimulates the phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway through PDGFR. In addition, we show that Gα12QL stimulates the phosphorylation of forkhead transcription factor FKHRL1 via AKT in a PDGFRα- and PI3K-dependent manner. Since AKT promotes cell growth by blocking the transcription of antiproliferative genes through the inhibitory phosphorylation of forkhead transcription factors, our results describe for the first time a PDGFRα-dependent signaling pathway involving PI3K-AKT-FKHRL1, regulated by Gα12QL in promoting cell growth. Consistent with this view, we demonstrate that the expression of a dominant negative mutant of PDGFRα attenuated Gα12-mediated neoplastic transformation of NIH 3T3 cells.

Stimulation of cell growth and proliferation in NIH-3T3 cells by onion and garlic oils

1986 ◽  
Vol 2 (3) ◽  
pp. 369-378 ◽  
Author(s):  
Judith T. Zelikoff ◽  
Norman M. Atkins ◽  
Sidney Belman
Keyword(s):  
Cell Growth ◽  
3T3 Cells ◽  
Cell Growth And Proliferation ◽  
Nih 3T3 ◽  
Stimulation Of ◽  
Nih 3T3 Cells

scholarly journals Cyclic AMP Blocks Cell Growth through Raf-1-Dependent and Raf-1-Independent Mechanisms

2002 ◽  
Vol 22 (11) ◽  
pp. 3717-3728 ◽  
Author(s):  
Nicolas Dumaz ◽  
Yvonne Light ◽  
Richard Marais
Keyword(s):  
Protein Kinase ◽  
Cell Growth ◽  
Cyclic Amp ◽  
3T3 Cells ◽  
Extracellular Signal ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

ABSTRACT It is widely accepted that cyclic AMP (cAMP) can block cell growth by phosphorylating Raf-1 on serine 43 and inhibiting signaling to extracellular signal-regulated protein kinase. We show that the suppression of Raf-1 by cAMP is considerably more complex than previously reported. When cellular cAMP is elevated, Raf-1 is phosphorylated on three residues (S43, S233, and S259), which work independently to block Raf-1. Both Ras-dependent and Ras-independent processes are disrupted. However, when cAMP-insensitive versions of Raf-1 are expressed in NIH 3T3 cells, their growth is still strongly suppressed when cAMP is elevated. Thus, although Raf-1 appears to be an important cAMP target, other pathways are also targeted by cAMP, providing alternative mechanisms that lead to suppression of cell growth.

Activin induces hepatocyte cell growth arrest through induction of the cyclin-dependent kinase inhibitor p15INK4B and Sp1

2004 ◽  
Vol 16 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Joanne Ho ◽  
Chantal de Guise ◽  
Christie Kim ◽  
Serge Lemay ◽  
Xiao-Fan Wang ◽  
...  
Keyword(s):  
Cell Growth ◽  
Kinase Inhibitor ◽  
Growth Arrest ◽  
Cyclin Dependent Kinase ◽  
Cell Growth Arrest ◽  
Cyclin Dependent Kinase Inhibitor

MiR-579-3p Protects Intestinal Mucosal Epithelial Cells from Hypoxia-Reoxygenation Injury by Targeting Cyclin-Dependent Kinase Inhibitor 1B

2021 ◽  
Vol 11 (6) ◽  
pp. 1084-1090
Author(s):  
Yuxiu Guo ◽  
Juan Ding ◽  
Wenjuan Yan
Keyword(s):  
Epithelial Cells ◽  
Western Blot ◽  
Kinase Inhibitor ◽  
Cell Activity ◽  
Luciferase Reporter ◽  
Cyclin Dependent Kinase ◽  
Apoptosis Rate ◽  
Cyclin Dependent Kinase Inhibitor ◽  
Reoxygenation Injury ◽  
Hypoxia Reoxygenation

Intestinal ischemia/reperfusion (I/R) injury is a common tissue and organ injury during surgery. This study explores miR-579-3p’s effect on the hypoxia-reoxygenation injury of intestinal mucosal epithelial cells via cyclin-dependent kinase inhibitor 1B (CDKN1B). Fetal human cells (FHC) cells, which are human normal colorectal mucosal epithelial cells, were cultured in vitro to establish a hypoxia-reoxygenation (H/R) cell model. Nano-based qRT-PCR and Western blot detected miR-579-3p and CDKN1B expressions in HCCLM3 cells treated with H/R. CCK-8 method and flow cytometry measured miR-579-3p and CDKN1B expressions on cell activity and death after H/R treatment. Dual-Luciferase reporter experiment and Western blot analyzed the relationship between miR-579-3p and CDKN1B. After the FHC cells were treated with H/R, miR-579-3p expression was decreased, whereas CDKN1B expression was increased (P < 0.05). FHC cells’ activity was decreased, and its apoptosis rate was upregulated; also, TNF-α and IL-6 protein levels were significantly enhanced (P < 0.05). Nevertheless, the activity of FHC cells treated with H/R after miR-579-3p overexpression was significantly increased, while the apoptosis rate was upregulation, and TNF-α level, IL-6 levels were reduced (P < 0.05). The effect of inhibiting CDKN1B expression was the same as that of overexpression miR-579-3p. After CDKN1B overexpression, the H/R-treated FHC cells’ viability was reduced, while the apoptosis rate was elevated, and TNF-α and IL-6 levels were elevated (P < 0.05). Compared to miR-579-3p overexpression, FHC cell activity in treated with H/R after the overexpression of miR-579-3p+CDKN1B was reduced. At the same time, the apoptosis rate and the level of TNF-α and IL-6 protein were elevated (P < 0.05). In summary, MiR-579-3p’s targeting of CDKN1B protects FHC cells from H/R injury by alleviating H/R-induced apoptosis and inflammation.

Oncogenic Transformation of NIH 3T3 Fibroblasts by BCR-ABL Oncoprotein Requires the IL-3 Receptor.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3370-3370
Author(s):  
Wenjing Tao ◽  
Hui Lin ◽  
Tong Sun ◽  
Ajoy K. Samanta ◽  
Ralph B. Arlinghaus
Keyword(s):  
Kinase Inhibitor ◽  
Philadelphia Chromosome ◽  
Cell System ◽  
Receptor Expression ◽  
Oncogenic Transformation ◽  
3T3 Cells ◽  
Lymphoid Leukemia ◽  
3T3 Fibroblasts ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

Abstract Bcr-Abl is a leukemia-inducing protein, which causes oncogenic transformation of myeloid progenitors in Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) and lymphoid progenitors in Ph+ acute lymphoid leukemia (ALL). Oncogenic transformation of hematopoietic cells by the Bcr-Abl oncoprotein directly involves the activation Jak2 tyrosine kinase and the Stat5 transcription factor. Both proteins are normally linked to the IL-3/GM-CSF receptors for growth and survival. Since fibroblastic cells are not targets of BCR-ABL induced oncogenesis, we determined whether forced expression of the IL-3 receptor would allow oncogenic transformation of NIH 3T3 fibroblasts known to be resistant to transformation by BCR-ABL. NIH 3T3 cells transduced with the human IL-3 receptor a and b chains were highly susceptible to oncogenic transformation by expression of BCR-ABL. Forced expression of both receptor chains but not either one alone allowed efficient foci formation of NIH 3T3 cells expressing BCR-ABL, and these cells formed colonies in soft agar whereas BCR-ABL positive NIH 3T3 cells lacking IL-3 receptor expression did not. The Bcr-Abl kinase inhibitor imatinib mesylate (1 mM) and the Jak kinase inhibitor AG490 (10 mM) strongly inhibited agar colony formation. A small molecule inhibitor of Jak2 kinase, 1,2,3,4,5,6-hexabromocyclohexane reported to be specific for Jak2 (Sandberg et al. J. Med. Chem, 2005)-significantly reduced the phosphorylation of Gab2 at the YxxM motif, which is needed for activation of the PI-3 kinase and Akt, two proteins that are part of the Bcr-Abl/Jak2 Network (Samanta et al. Cancer Res, 2006). These findings indicate that Bcr-Abl oncoprotein requires the IL-3 receptor/Jak2/Stat5 pathways for oncogenic transformation of NIH 3T3 fibroblasts, and may explain partially why Bcr-Abl oncogenesis is restricted to hematopoietic malignancies. Furthermore, this cell system in fibroblastic and other cell lineages will provide a model to probe the detailed steps that require IL-3 receptor and Jak2 for Bcr-Abl induced leukemia.

scholarly journals The Oncogenic TLS-ERG Fusion Protein Exerts Different Effects in Hematopoietic Cells and Fibroblasts

2005 ◽  
Vol 25 (14) ◽  
pp. 6235-6246 ◽  
Author(s):  
Junhui Zou ◽  
Hitoshi Ichikawa ◽  
Michael L. Blackburn ◽  
Hsien-Ming Hu ◽  
Anna Zielinska-Kwiatkowska ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Rna Polymerase Ii ◽  
Hematopoietic Cells ◽  
Cellular Transformation ◽  
Luciferase Reporter ◽  
3T3 Cells ◽  
Pol Ii ◽  
G Cells ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

ABSTRACT The oncogenic TLS-ERG fusion protein is found in human myeloid leukemia and Ewing's sarcoma as a result of specific chromosomal translocation. To unveil the potential mechanism(s) underlying cellular transformation, we have investigated the effects of TLS-ERG on both gene transcription and RNA splicing. Here we show that the TLS protein forms complexes with RNA polymerase II (Pol II) and the serine-arginine family of splicing factors in vivo. Deletion analysis of TLS-ERG in both mouse L-G myeloid progenitor cells and NIH 3T3 fibroblasts revealed that the RNA Pol II-interacting domain of TLS-ERG resides within the first 173 amino acids. While TLS-ERG repressed expression of the luciferase reporter gene driven by glycoprotein IX promoter in L-G cells but not in NIH 3T3 cells, the fusion protein was able to affect splicing of the E1A reporter in NIH 3T3 cells but not in L-G cells. To identify potential target genes of TLS-ERG, the fusion protein and its mutants were stably expressed in both L-G and NIH 3T3 cells through retroviral transduction. Microarray analysis of RNA samples from these cells showed that TLS-ERG activates two different sets of genes sharing little similarity in the two cell lines. Taken together, these results suggest that the oncogenic TLS-ERG fusion protein transforms hematopoietic cells and fibroblasts via different pathways.

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