scholarly journals Effects of Auraptene on IGF-1 Stimulated Cell Cycle Progression in the Human Breast Cancer Cell Line, MCF-7

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Prasad Krishnan ◽  
Heather Kleiner-Hancock
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
D1 Protein ◽  
Cancer Cell Line ◽  
S Phase ◽  
Human Breast ◽  
Cycle Progression ◽  
Cyclin D1 Protein ◽  
Mcf 7

Auraptene is being investigated for its chemopreventive effects in many models of cancer including skin, colon, prostate, and breast. Many mechanisms of action including anti-inflammatory, antiproliferative, and antiapoptotic effects are being suggested for the chemopreventive properties of auraptene. We have previously shown in theN-methylnitrosourea induced mammary carcinogenesis model that dietary auraptene (500 ppm) significantly delayed tumor latency. The delay in time to tumor corresponded with a significant reduction in cyclin D1 protein expression in the tumors. Since cyclin D1 is a major regulator of cell cycle, we further studied the effects of auraptene on cell cycle and the genes related to cell cycle in MCF-7 cells. Here we show that auraptene significantly inhibited IGF-1 stimulated S phase of cell cycle in MCF-7 cells and significantly changed the transcription of many genes involved in cell cycle.

scholarly journals Differential effects of 16α-hydroxyestrone and 2-methoxyestradiol on cyclin D1 involving the transcription factor ATF-2 in MCF-7 breast cancer cells

2005 ◽  
Vol 34 (1) ◽  
pp. 91-105 ◽  
Author(s):  
Joan S Lewis ◽  
T J Thomas ◽  
Richard G Pestell ◽  
Chris Albanese ◽  
Michael A Gallo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Dna Synthesis ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
D1 Protein ◽  
Fold Increase ◽  
Cycle Progression ◽  
Cyclin D1 Protein ◽  
Mcf 7

We studied the effects of 2-methoxyestradiol (2-ME2) and 16α-hydroxyestrone (16α-OHE1), two metabolites of estradiol (E2), on DNA synthesis, cell cycle progression and cyclin D1 protein levels in estrogen receptor-positive MCF-7 cells. E2 and 16α-OHE1 stimulated DNA synthesis, and 2-ME2 inhibited the stimulatory effects of these agents. E2 and 16α-OHE1 stimulated the progression of cells from G1 to S phase and this effect was attenuated by 2-ME2. Western blot analysis showed that E2 and 16α-OHE1 increased cyclin D1 protein level by about fourfold compared with control. 2-ME2 had no significant effect on cyclin D1; however, it prevented the accumulation of cyclin D1 in the presence of E2 and 16α-OHE1. Cells transfected with a cyclin D1 reporter gene and treated with E2 or 16α-OHE1 showed 7- and 9.5-fold increase respectively in promoter activity compared with control. This activity was significantly inhibited by 2-ME2. Cyclin D1 transactivation was mediated by the cAMP response element (CRE) region, which binds activating transcription factor 2 (ATF-2). DNA affinity assay showed 2.5- and 3.5-fold increases in ATF-2 binding to CRE in the presence of E2 and 16α-OHE1 respectively. The binding of ATF-2 was inhibited by the presence of 2-ME2. These results show that 2-ME2 can downregulate cyclin D1 and thereby cell cycle progression by a mechanism involving the disruption of ATF-2 binding to cyclin D1 promoter.

scholarly journals Cellular Ras and Cyclin D1 Are Required during Different Cell Cycle Periods in Cycling NIH 3T3 Cells

1999 ◽  
Vol 19 (7) ◽  
pp. 4623-4632 ◽  
Author(s):  
Masahiro Hitomi ◽  
Dennis W. Stacey
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Time Lapse ◽  
S Phase ◽  
3T3 Cells ◽  
Cycle Progression ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

ABSTRACT Novel techniques were used to determine when in the cell cycle of proliferating NIH 3T3 cells cellular Ras and cyclin D1 are required. For comparison, in quiescent cells, all four of the inhibitors of cell cycle progression tested (anti-Ras, anti-cyclin D1, serum removal, and cycloheximide) became ineffective at essentially the same point in G1 phase, approximately 4 h prior to the beginning of DNA synthesis. To extend these studies to cycling cells, a time-lapse approach was used to determine the approximate cell cycle position of individual cells in an asynchronous culture at the time of inhibitor treatment and then to determine the effects of the inhibitor upon recipient cells. With this approach, anti-Ras antibody efficiently inhibited entry into S phase only when introduced into cells prior to the preceding mitosis, several hours before the beginning of S phase. Anti-cyclin D1, on the other hand, was an efficient inhibitor when introduced up until just before the initiation of DNA synthesis. Cycloheximide treatment, like anti-cyclin D1 microinjection, was inhibitory throughout G1 phase (which lasts a total of 4 to 5 h in these cells). Finally, serum removal blocked entry into S phase only during the first hour following mitosis. Kinetic analysis and a novel dual-labeling technique were used to confirm the differences in cell cycle requirements for Ras, cyclin D1, and cycloheximide. These studies demonstrate a fundamental difference in mitogenic signal transduction between quiescent and cycling NIH 3T3 cells and reveal a sequence of signaling events required for cell cycle progression in proliferating NIH 3T3 cells.

scholarly journals Growth factor, steroid, and steroid antagonist regulation of cyclin gene expression associated with changes in T-47D human breast cancer cell cycle progression.

1993 ◽  
Vol 13 (6) ◽  
pp. 3577-3587 ◽  
Author(s):  
E A Musgrove ◽  
J A Hamilton ◽  
C S Lee ◽  
K J Sweeney ◽  
C K Watts ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Cell Cycle ◽  
Cyclin D1 ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Cell Cycle Progression ◽  
S Phase ◽  
G1 Phase ◽  
Cycle Progression

Cyclins and proto-oncogenes including c-myc have been implicated in eukaryotic cell cycle control. The role of cyclins in steroidal regulation of cell proliferation is unknown, but a role for c-myc has been suggested. This study investigated the relationship between regulation of T-47D breast cancer cell cycle progression, particularly by steroids and their antagonists, and changes in the levels of expression of these genes. Sequential induction of cyclins D1 (early G1 phase), D3, E, A (late G1-early S phase), and B1 (G2 phase) was observed following insulin stimulation of cell cycle progression in serum-free medium. Transient acceleration of G1-phase cells by progestin was also accompanied by rapid induction of cyclin D1, apparent within 2 h. This early induction of cyclin D1 and the ability of delayed administration of antiprogestin to antagonize progestin-induced increases in both cyclin D1 mRNA and the proportion of cells in S phase support a central role for cyclin D1 in mediating the mitogenic response in T-47D cells. Compatible with this hypothesis, antiestrogen treatment reduced the expression of cyclin D1 approximately 8 h before changes in cell cycle phase distribution accompanying growth inhibition. In the absence of progestin, antiprogestin treatment inhibited T-47D cell cycle progression but in contrast did not decrease cyclin D1 expression. Thus, changes in cyclin D1 gene expression are often, but not invariably, associated with changes in the rate of T-47D breast cancer cell cycle progression. However, both antiestrogen and antiprogestin depleted c-myc mRNA by > 80% within 2 h. These data suggest the involvement of both cyclin D1 and c-myc in the steroidal control of breast cancer cell cycle progression.

scholarly journals Inhibitory Effects of 1α,25-Dihydroxyvitamin D3 on the G1–S Phase-Controlling Machinery

2001 ◽  
Vol 15 (8) ◽  
pp. 1370-1380 ◽  
Author(s):  
Simon Skjøde Jensen ◽  
Mogens Winkel Madsen ◽  
Jiri Lukas ◽  
Lise Binderup ◽  
Jiri Bartek
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Time Course ◽  
Cancer Cell Line ◽  
Cyclin A ◽  
S Phase ◽  
Cyclin D3 ◽  
G1 Arrest ◽  
Dihydroxyvitamin D3 ◽  
Mcf 7

Abstract The nuclear hormone 1α,25-dihydroxyvitamin D3 induces cell cycle arrest, differentiation, or apoptosis depending on target cell type and state. Although the antiproliferative effect of 1α,25-dihydroxyvitamin D3 has been known for years, the molecular basis of the cell cycle blockade by 1α,25-dihydroxyvitamin D3 remains largely unknown. Here we have investigated the mechanisms underlying the G1 arrest induced upon 1α,25-dihydroxyvitamin D3 treatment of the human breast cancer cell line MCF-7. Twenty-four-hour exposure of exponentially growing MCF-7 cells to 1α,25-dihydroxyvitamin D3 impeded proliferation by preventing S phase entry, an effect that correlated with appearance of the growth-suppressing, hypophosphorylated form of the retinoblastoma protein (pRb), and modulation of cyclin-dependent kinase (cdk) activities of cdk-4, -6, and -2. Time course immunochemical and biochemical analyses of the cellular and molecular effects of 1α,25-dihydroxyvitamin D3 treatment for up to 6 d revealed a dynamic chain of events, preventing activation of cyclin D1/cdk4, and loss of cyclin D3, which collectively lead to repression of the E2F transcription factors and thus negatively affected cyclin A protein expression. While the observed 10-fold inhibition of cyclin D1/cdk 4-associated kinase activity appeared independent of cdk inhibitors, the activity of cdk 2 decreased about 20-fold, reflecting joint effects of the lower abundance of its cyclin partners and a significant increase of the cdk inhibitor p21CIP1/WAF1, which blocked the remaining cyclin A(E)/cdk 2 complexes. Together with a rapid down-modulation of the c-Myc oncoprotein in response to 1α,25-dihydroxyvitamin D3, these results demonstrate that 1α,25-dihydroxyvitamin D3 inhibits cell proliferation by targeting several key regulators governing the G1/S transition.

scholarly journals Multifaceted Regulation of Cell Cycle Progression by Estrogen: Regulation of Cdk Inhibitors and Cdc25A Independent of Cyclin D1-Cdk4 Function

2001 ◽  
Vol 21 (3) ◽  
pp. 794-810 ◽  
Author(s):  
James S. Foster ◽  
Donald C. Henley ◽  
Antonin Bukovsky ◽  
Prem Seth ◽  
Jay Wimalasena
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Inhibitory Activity ◽  
Cell Cycle Progression ◽  
Estrogen Action ◽  
Cycle Progression ◽  
Cdk2 Activity ◽  
Mcf 7

ABSTRACT Estrogens induce proliferation of estrogen receptor (ER)-positive MCF-7 breast cancer cells by stimulating G1/S transition associated with increased cyclin D1 expression, activation of cyclin-dependent kinases (Cdks), and phosphorylation of the retinoblastoma protein (pRb). We have utilized blockade of cyclin D1-Cdk4 complex formation through adenovirus-mediated expression of p16INK4a to demonstrate that estrogen regulates Cdk inhibitor expression and expression of the Cdk-activating phosphatase Cdc25A independent of cyclin D1-Cdk4 function and cell cycle progression. Expression of p16INK4a inhibited G1/S transition induced in MCF-7 cells by 17-β-estradiol (E2) with associated inhibition of both Cdk4- and Cdk2-associated kinase activities. Inhibition of Cdk2 activity was associated with delayed removal of Cdk-inhibitory activity in early G1 and decreased cyclin A expression. Cdk-inhibitory activity and expression of both p21Cip1 and p27Kip1 was decreased, however, in both control and p16INK4a-expressing cells 20 h after estrogen treatment. Expression of Cdc25A mRNA and protein was induced by E2 in control and p16INK4a-expressing MCF-7 cells; however, functional activity of Cdc25A was inhibited in cells expressing p16INK4a. Inhibition of Cdc25A activity in p16INK4a-expressing cells was associated with depressed Cdk2 activity and was reversed in vivo and in vitro by active Cdk2. Transfection of MCF-7 cells with a dominant-negative Cdk2 construct inhibited the E2-dependent activation of ectopic Cdc25A. Supporting a role for Cdc25A in estrogen action, antisenseCDC25A oligonucleotides inhibited estrogen-induced Cdk2 activation and DNA synthesis. In addition, inactive cyclin E-Cdk2 complexes from p16INK4a-expressing, estrogen-treated cells were activated in vitro by treatment with recombinant Cdc25A and in vivo in cells overexpressing Cdc25A. The results demonstrate that functional association of cyclin D1-Cdk4 complexes is required for Cdk2 activation in MCF-7 cells and that Cdk2 activity is, in turn, required for the in vivo activation of Cdc25A. These studies establish Cdc25A as a growth-promoting target of estrogen action and further indicate that estrogens independently regulate multiple components of the cell cycle machinery, including expression of p21Cip1 and p27Kip1.

scholarly journals The RASSF1A Tumor Suppressor Restrains Anaphase-Promoting Complex/Cyclosome Activity during the G1/S Phase Transition To Promote Cell Cycle Progression in Human Epithelial Cells

2008 ◽  
Vol 28 (10) ◽  
pp. 3190-3197 ◽  
Author(s):  
Angelique W. Whitehurst ◽  
Rosalyn Ram ◽  
Latha Shivakumar ◽  
Boning Gao ◽  
John D. Minna ◽  
...  
Keyword(s):  
Phase Transition ◽  
Cell Cycle ◽  
Tumor Suppressor ◽  
Epithelial Cells ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Phase Cell ◽  
Anaphase Promoting Complex ◽  
Cycle Progression

ABSTRACT Multiple molecular lesions in human cancers directly collaborate to deregulate proliferation and suppress apoptosis to promote tumorigenesis. The candidate tumor suppressor RASSF1A is commonly inactivated in a broad spectrum of human tumors and has been implicated as a pivotal gatekeeper of cell cycle progression. However, a mechanistic account of the role of RASSF1A gene inactivation in tumor initiation is lacking. Here we have employed loss-of-function analysis in human epithelial cells for a detailed investigation of the contribution of RASSF1 to cell cycle progression. We found that RASSF1A has dual opposing regulatory connections to G1/S phase cell cycle transit. RASSF1A associates with the Ewing sarcoma breakpoint protein, EWS, to limit accumulation of cyclin D1 and restrict exit from G1. Surprisingly, we found that RASSF1A is also required to restrict SCFβTrCP activity to allow G/S phase transition. This restriction is required for accumulation of the anaphase-promoting complex/cyclosome (APC/C) inhibitor Emi1 and the concomitant block of APC/C-dependent cyclin A turnover. The consequence of this relationship is inhibition of cell cycle progression in normal epithelial cells upon RASSF1A depletion despite elevated cyclin D1 concentrations. Progression to tumorigenicity upon RASSF1A gene inactivation should therefore require collaborating genetic aberrations that bypass the consequences of impaired APC/C regulation at the G1/S phase cell cycle transition.

scholarly journals Id2 specifically alters regulation of the cell cycle by tumor suppressor proteins.

1996 ◽  
Vol 16 (6) ◽  
pp. 2570-2578 ◽  
Author(s):  
A Lasorella ◽  
A Iavarone ◽  
M A Israel
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Cell Cycle Progression ◽  
D1 Protein ◽  
Protein Kinase Activity ◽  
Cycle Progression ◽  
Tumor Suppressor Proteins ◽  
Cycle Arrest

Cells which are highly proliferative typically lack expression of differentiated, lineage-specific characteristics. Id2, a member of the helix-loop-helix (HLH) protein family known to inhibit cell differentiation, binds to the retinoblastoma protein (pRb) and abolishes its growth-suppressing activity. We found that Id2 but not Id1 or Id3 was able to bind in vitro not only pRb but also the related proteins p107 and p130. Also, an association between Id2 and p107 or p130 was observed in vivo in transiently transfected Saos-2 cells. In agreement with these results, expression of Id1 or Id3 did not affect the block of cell cycle progression mediated by pRb. Conversely, expression of Id2 specifically reversed the cell cycle arrest induced by each of the three members of the pRb family. Furthermore, the growth-suppressive activities of cyclin-dependent kinase inhibitors p16 and p21 were efficiently antagonized by high levels of Id2 but not by Id1 Id3. Consistent with the role of p16 as a selective inhibitor of pRb and pRb-related protein kinase activity, p16-imposed cell cycle arrest was completely abolished by Id2. Only a partial reversal of p21-induced growth suppression was observed, which correlated with the presence of a functional pRb. We also documented decreased levels of cyclin D1 protein and mRNA and the loss of cyclin D1-cdk4 complexes in cells constitutively expressing Id2. These data provide evidence for important Id2-mediated alterations in cell cycle components normally involved in the regulatory events of cell cycle progression, and they highlight a specific role for Id2 as an antagonist of multiple tumor suppressor proteins.

scholarly journals Review of: c-Myc suppresses p21WAF1/CIP1expression during oestrogen signalling and antioestrogen resistance in human breast cancer cells

2006 ◽  
Vol 9 (5) ◽  
pp. 1-4
Author(s):  
C. M. McNeil ◽  
E. A. Musgrove
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cancer Cells ◽  
Human Breast Cancer ◽  
Breast Cancer Cells ◽  
Cell Cycle Progression ◽  
Human Breast ◽  
Cycle Progression ◽  
Oestrogen Treatment ◽  
Mcf 7

Citation of original article:S. Mukherjee, S. E. Conrad.Journal of Biological Chemistry2005;280: 17616–17625.Abstract of the original article:Oestrogen rapidly induces expression of the proto-oncogene c-Myc. c-Myc is required for oestrogen-stimulated proliferation of breast cancer cells, and deregulated c-Myc expression has been implicated in antioestrogen resistance. In this report, we investigate the mechanism(s) by which c-Myc mediates oestrogen-stimulated proliferation and contributes to cell cycle progression in the presence of antioestrogen. The MCF-7 cell line is a model of oestrogen-dependent, antioestrogen-sensitive human breast cancer. Using stable MCF-7 derivatives with inducible c-Myc expression, we demonstrated that in antioestrogen-treated cells, the elevated mRNA and protein levels of p21WAF1/CIP1, a cell cycle inhibitor, decreased upon either c-Myc induction or oestrogen treatment. Expression of p21 blocked c-Myc-mediated cell cycle progression in the presence of antioestrogen, suggesting that the decrease in p21WAF1/CIP1is necessary for this process. Using RNA interference to suppress c-Myc expression, we further established that c-Myc is required for oestrogen-mediated decreases in p21WAF1/CIP1. Finally, we observed that neither c-Myc nor p21WAF1/CIP1is regulated by oestrogen or antioestrogen in an antioestrogen-resistant MCF-7 derivative. The p21 levels in the antioestrogen-resistant cells increased when c-Myc expression was suppressed, suggesting that loss of p21 regulation was a consequence of constitutive c-Myc expression. Together, these studies implicate p21WAF1/CIP1as an important target of c-Myc in breast cancer cells and provide a link between oestrogen, c-Myc, and the cell cycle machinery. They further suggest that aberrant c-Myc expression, which is frequently observed in human breast cancers, can contribute to antioestrogen resistance by altering p21WAF1/CIP1regulation.

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