scholarly journals Growth factor-deprived BALB/c 3T3 murine fibroblasts can enter the S phase after induction of c-myc gene expression.

1987 ◽  
Vol 7 (10) ◽  
pp. 3554-3560 ◽  
Author(s):  
F Cavalieri ◽  
M Goldfarb

Induction of quiescent BALB/c 3T3 murine fibroblasts by platelet-derived growth factor (PDGF) or fibroblast growth factor (FGFs) is accompanied by induction of c-myc gene expression. To study the role of c-myc in cell growth, we transfected BALB/c 3T3 cells with a plasmid construct containing a glucocorticoid-inducible c-myc gene. When these transfected cells were growth arrested in PDGF-FGF-freedefined medium, glucocorticoid treatment induced S-phase DNA synthesis. This induction of DNA synthesis was inefficient, and cell proliferation was not evident, suggesting that growth factors act through stimulation of c-myc expression together with other intracellular events.

1987 ◽  
Vol 7 (10) ◽  
pp. 3554-3560
Author(s):  
F Cavalieri ◽  
M Goldfarb

Induction of quiescent BALB/c 3T3 murine fibroblasts by platelet-derived growth factor (PDGF) or fibroblast growth factor (FGFs) is accompanied by induction of c-myc gene expression. To study the role of c-myc in cell growth, we transfected BALB/c 3T3 cells with a plasmid construct containing a glucocorticoid-inducible c-myc gene. When these transfected cells were growth arrested in PDGF-FGF-freedefined medium, glucocorticoid treatment induced S-phase DNA synthesis. This induction of DNA synthesis was inefficient, and cell proliferation was not evident, suggesting that growth factors act through stimulation of c-myc expression together with other intracellular events.


2007 ◽  
Vol 214 (2) ◽  
pp. 465-473 ◽  
Author(s):  
Daisuke Nanba ◽  
Hirofumi Inoue ◽  
Yuka Shigemi ◽  
Yuji Shirakata ◽  
Koji Hashimoto ◽  
...  

1983 ◽  
Vol 3 (1) ◽  
pp. 70-81 ◽  
Author(s):  
C D Scher ◽  
R L Dick ◽  
A P Whipple ◽  
K L Locatell

The platelet-derived growth factor (PDGF) stimulates density-arrested BALB/c-3T3 cells to synthesize a protein (pII; Mr, 35,000) that is constitutively synthesized by spontaneously transformed BALB/c-3T3 (ST2-3T3) cells which do not require PDGF for growth. Antisera against a major excreted protein family (MEP) of retrovirus-transformed cells quantitatively precipitated cellular pII. PDGF-stimulated pII has the same molecular weight, a similar charge, and similar antigenic determinants as authentic MEP isolated from ST2-3T3 or retrovirus-transformed cells. MEP represented about 2% of the nonnuclear proteins synthesized by ST2-3T3 cells and 0.3 to 0.6% of the proteins synthesized by PDGF-treated BALB/c-3T3 cells, a three- to sixfold increase over the background. In BALB/c-3T3 cells, less PDGF was required for pII (MEP) synthesis than for DNA synthesis. PDGF induced a selective increase in pII (MEP) within 40 min. Such preferential synthesis was inhibited by brief treatment with actinomycin D, suggesting a requirement for newly formed RNA. The constitutive synthesis of pII (MEP) by ST2-3T3 cells was not inhibited by actinomycin D. Five spontaneously or chemical carcinogen-transformed tumorigenic BALB/c-3T3 cell lines were studied; they neither required PDGF for growth nor responded to it. These cell lines became arrested at confluence with a G1 DNA content. Each of these independently isolated lines synthesized pII (MEP) constitutively. Thus, the synthesis of pII (MEP) may be required, but is not sufficient, for PDGF-modulated DNA synthesis.


1984 ◽  
Vol 4 (9) ◽  
pp. 1807-1814
Author(s):  
J Campisi ◽  
A B Pardee

The control of eucaryotic cell proliferation is governed largely by a series of regulatory events which occur in the G1 phase of the cell cycle. When stimulated to proliferate, quiescent (G0) 3T3 fibroblasts require transcription, rapid translation, and three growth factors for the growth state transition. We examined exponentially growing 3T3 cells to relate the requirements for G1 transit to those necessary for the transition from the G0 to the S phase. Cycling cells in the G1 phase required transcription, rapid translation, and a single growth factor (insulin-like growth factor [IGF] I) to initiate DNA synthesis. IGF I acted post-transcriptionally at a late G1 step. All cells in the G1 phase entered the S phase on schedule if either insulin (hyperphysiological concentration) or IGF I (subnanomolar concentration) was provided as the sole growth factor. In medium lacking all growth factors, only cells within 2 to 3 h of the S phase were able to initiate DNA synthesis. Similarly, cells within 2 to 3 h of the S phase were less dependent on transcription and translation for entry into the S phase. Cells responded very differently to inhibited translation than to growth factor deprivation. Cells in the early and mid-G1 phases did not progress toward the S phase during transcriptional or translational inhibition, and during translational inhibition they actually regressed from the S phase. In the absence of growth factors, however, these cells continued progressing toward the S phase, but still required IGF at a terminal step before initiating DNA synthesis. We conclude that a suboptimal condition causes cells to either progress or regress in the cell cycle rather than freezing them at their initial position. By using synchronized cultures, we also show that in contrast to earlier events, this final, IGF-dependent step did not require new transcription. This result is in contrast to findings that other growth factors induce new transcription. We examined the requirements for G1 transit by using a chemically transformed 3T3 cell line (BPA31 cells) which has lost some but not all ability to regulate its growth. Early- and mid-G1-phase BPA31 cells required transcription and translation to initiate DNA synthesis, although they did not regress from the S phase during translational inhibition. However, these cells did not need IGF for entry into the S phase.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
I Muñoa ◽  
M Araolaza-Lasa ◽  
I Urizar-Arenaza ◽  
M Gianzo Citores ◽  
N Subiran Ciudad

Abstract Study question To elucidate if morphine can alter embryo development. Summary answer Chronic morphine treatment regulates BMP4 growth factor, in terms of gene expression and H3K27me3 enrichment and promotes in-vitro blastocysts development and PGC formation. What is known already BMP4 is a member of the bone morphogenetic protein family, which acts mainly through SMAD dependent pathway, to play an important role in early embryo development. Indeed, BMP4 enhances pluripotency in mouse embryonic stem cells (mESCs) and, specifically, is involved in blastocysts formation and primordial germ cells (PGCs) generation. Although, external morphine influence has been previously reported on the early embryo development, focus on implantation and uterus function, there is a big concern in understanding how environmental factors can cause stable epigenetic changes, which could be maintained during development and lead to health problems. Study design, size, duration First, OCT4-reported mESCs were chronically treated with morphine during 24h, 10–5mM. After morphine removal, mESCs were collected for RNA-seq and H3K27me3 ChIP-seq study. To elucidate the role of morphine in early embryo development, two cell- embryos stage were chronically treated with morphine for 24h and in-vitro cultured up to the blastocyst stage in the absence of morphine. Furthermore, after morphine treatment mESCs were differentiated to PGCs, to elucidate the role of morphine in PGC differentiation. Participants/materials, setting, methods Transcriptomic analyses and H3K27me3 genome wide distribution were carried out by RNA-Sequencing and Chip-Sequencing respectively. Validations were performed by RNA-RT-qPCR and Chip-RT-qPCR. Main results and the role of chance Dynamic transcriptional analyses identified a total of 932 differentially expressed genes (DEGs) after morphine treatment on mESCs, providing strong evidence of a transcriptional epigenetic effect induced by morphine. High-throughput screening approaches showed up Bmp4 as one of the main morphine targets on mESCs. Morphine caused an up-regulation of Bmp4 gene expression together with a decrease of H3K27me3 enrichment at promoter level. However, no significant differences were observed on gene expression and H3K27me3 enrichment on BMP4 signaling pathway components (such as Smad1, Smad4, Smad5, Smad7, Prdm1 and Prmd14) after morphine treatment. On the other hand, the Bmp4 gene expression was also up-regulated in in-vitro morphine treated blastocyst and in-vitro morphine treated PGCs. These results were consistent with the increase in blastocyst rate and PGC transformation rate observed after morphine chronic treatment. Limitations, reasons for caution To perform the in-vitro analysis. Further studies are needed to describe the whole signaling pathways underlying BMP4 epigenetic regulation after morphine treatment. Wider implications of the findings: Our findings confirmed that mESCs and two-cell embryos are able to memorize morphine exposure and promote both blastocyst development and PGCs formation through potentially BMP4 epigenetic regulation. These results provide insights understanding how environmental factors can cause epigenetic changes during the embryo development, leading to alterations and producing health problems/diseases Trial registration number Not applicable


1994 ◽  
Vol 267 (4) ◽  
pp. F528-F536 ◽  
Author(s):  
G. Grandaliano ◽  
G. G. Choudhury ◽  
P. Biswas ◽  
H. E. Abboud

Thrombin elicits multiple biological effects on a variety of cells. We have previously shown that thrombin is a potent mitogen for human glomerular mesangial cells. This mitogenic effect of thrombin is associated with activation of phospholipase C (PLC) and induction of platelet-derived growth factor (PDGF) gene expression. The thrombin receptor, which belongs to the guanine nucleotide binding protein (G protein)-coupled receptor family, has recently been shown to induce rapid tyrosine phosphorylation of cellular proteins. In the present study, we investigated the role of protein-tyrosine phosphorylation in mediating the cellular responses elicited by thrombin in human glomerular mesangial cells. Amino acid labeling followed by immunoprecipitation with phosphotyrosine antibodies demonstrate that thrombin stimulates tyrosine phosphorylation of a set of cellular proteins. Treatment of mesangial cells with thrombin followed by immunoblotting with phosphotyrosine antibodies showed three major bands of tyrosine-phosphorylated proteins approximately 130, 70, and 44-42 kDa. Phosphorylation of these proteins was inhibited by two tyrosine kinase inhibitors, herbimycin A and genistein. Both compounds inhibited DNA synthesis and PDGF B-chain gene expression but had no effect on inositol phosphates production or increases in cytosolic calcium in response to thrombin. These data demonstrate that protein-tyrosine phosphorylation is not required for thrombin-induced PLC activation with inositol phosphate formation and subsequent intracellular calcium release, but it is an absolute requirement for thrombin-induced DNA synthesis and PDGF B-chain gene expression.


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