A novel antioestrogen agent (3R,6R)-bassiatin inhibits cell proliferation and cell cycle progression by repressing cyclin D1 expression in 17β-oestradiol-treated MCF-7 cells

2011 ◽  
Vol 35 (6) ◽  
pp. 599-605 ◽  
Author(s):  
Li Meng ◽  
Bo Feng ◽  
Hongwen Tao ◽  
Tingting Yang ◽  
Yan Meng ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Mcf 7

Functional and molecular identification of intermediate-conductance Ca2+-activated K+ channels in breast cancer cells: association with cell cycle progression

2004 ◽  
Vol 287 (1) ◽  
pp. C125-C134 ◽  
Author(s):  
Halima Ouadid-Ahidouch ◽  
Morad Roudbaraki ◽  
Philippe Delcourt ◽  
Ahmed Ahidouch ◽  
Nathalie Joury ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Membrane Potential ◽  
Current Density ◽  
Cell Cycle Progression ◽  
G1 Phase ◽  
Cycle Progression ◽  
Mcf 7 ◽  
In Cells

We have previously reported that the hEAG K+ channels are responsible for the potential membrane hyperpolarization that induces human breast cancer cell progression into the G1 phase of the cell cycle. In the present study, we evaluate the role and functional expression of the intermediate-conductance Ca2+-activated K+ channel, hIK1-like, in controlling cell cycle progression. Our results demonstrate that hIK1 current density increased in cells synchronized at the end of the G1 or S phase compared with those in the early G1 phase. This increased current density paralleled the enhancement in hIK1 mRNA levels and the highly negative membrane potential. Furthermore, in cells synchronized at the end of G1 or S phases, basal cytosolic Ca2+ concentration ([Ca2+]i) was also higher than in cells arrested in early G1. Blocking hIK1 channels with a specific blocker, clotrimazole, induced both membrane potential depolarization and a decrease in the [Ca2+]i in cells arrested at the end of G1 and S phases but not in cells arrested early in the G1 phase. Blocking hIK1 with clotrimazole also induced cell proliferation inhibition but to a lesser degree than blocking hEAG with astemizole. The two drugs were essentially additive, inhibiting MCF-7 cell proliferation by 82% and arresting >90% of cells in the G1 phase. Thus, although the progression of MCF-7 cells through the early G1 phase is dependent on the activation of hEAG K+ channels, when it comes to G1 and checkpoint G1/S transition, the membrane potential appears to be primarily dependent on the hIK1-activity level.

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 PSMC2 Regulates Cell Cycle Progression Through the p21/Cyclin D1 Pathway and Predicts a Poor Prognosis in Human Hepatocellular Carcinoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Yiwei Liu ◽  
Hairong Chen ◽  
Xiangcheng Li ◽  
Feng Zhang ◽  
Lianbao Kong ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Cox Regression ◽  
Disease Free Survival ◽  
Luciferase Reporter ◽  
Cycle Progression ◽  
Cox Regression Analysis

Proteasome 26S subunit ATPase 2 (PSMC2) plays a pathogenic role in various cancers. However, its function and molecular mechanism in hepatocellular carcinoma (HCC) remain unknown. In this study, tissue microarray (TMA) analysis showed that PSMC2 is highly expressed in HCC tumors and correlates with poor overall and disease-free survival in HCC patients. Multivariate Cox regression analysis revealed that PSMC2 is an independent prognostic factor for HCC patients. Furthermore, our results showed that PSMC2 knockdown inhibited cell proliferation and suppressed tumorigenesis in vivo. Knockdown of PSMC2 increased the expression of p21 and therefore decreased the expression of cyclin D1. Dual-luciferase reporter assays indicated that depletion of PSMC2 significantly enhanced the promoter activity of p21. Importantly, PSMC2 knockdown-induced phenotypes were also rescued by downregulation of P21. Taken together, our data suggest that PSMC2 promotes HCC cell proliferation and cell cycle progression through the p21/cyclin D1 signaling pathway and could be a promising diagnostic and therapeutic target for HCC patients.

scholarly journals The NF2 Tumor Suppressor Gene Product, Merlin, Inhibits Cell Proliferation and Cell Cycle Progression by Repressing Cyclin D1 Expression

2005 ◽  
Vol 25 (6) ◽  
pp. 2384-2394 ◽  
Author(s):  
Guang-Hui Xiao ◽  
Ryan Gallagher ◽  
Justin Shetler ◽  
Kristine Skele ◽  
Deborah A. Altomare ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Tumor Suppressor ◽  
Cyclin D1 ◽  
Tumor Suppressor Gene ◽  
Promoter Activity ◽  
Cell Cycle Progression ◽  
Malignant Tumors ◽  
Suppressor Gene ◽  
Cycle Progression

ABSTRACT Inactivation of the NF2 tumor suppressor gene has been observed in certain benign and malignant tumors. Recent studies have demonstrated that merlin, the product of the NF2 gene, is regulated by Rac/PAK signaling. However, the mechanism by which merlin acts as a tumor suppressor has remained obscure. In this report, we show that adenovirus-mediated expression of merlin in NF2-deficient tumor cells inhibits cell proliferation and arrests cells at G1 phase, concomitant with decreased expression of cyclin D1, inhibition of CDK4 activity, and dephosphorylation of pRB. The effect of merlin on cell cycle progression was partially overridden by ectopic expression of cyclin D1. RNA interference experiments showed that silencing of the endogenous NF2 gene results in upregulation of cyclin D1 and S-phase entry. Furthermore, PAK1-stimulated cyclin D1 promoter activity was repressed by cotransfection of NF2, and PAK activity was inhibited by expression of merlin. Interestingly, the S518A mutant form of merlin, which is refractory to phosphorylation by PAK, was more efficient than the wild-type protein in inhibiting cell cycle progression and in repressing cyclin D1 promoter activity. Collectively, our data indicate that merlin exerts its antiproliferative effect, at least in part, via repression of PAK-induced cyclin D1 expression, suggesting a unifying mechanism by which merlin inactivation might contribute to the overgrowth seen in both noninvasive and malignant tumors.

scholarly journals RhoE Inhibits Cell Cycle Progression and Ras-Induced Transformation

2004 ◽  
Vol 24 (18) ◽  
pp. 7829-7840 ◽  
Author(s):  
Priam Villalonga ◽  
Rosa M. Guasch ◽  
Kirsi Riento ◽  
Anne J. Ridley
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cyclin D1 ◽  
Rho Gtpases ◽  
Cell Cycle Progression ◽  
Inhibitory Effect ◽  
Cell Cycle Checkpoint ◽  
Actin Stress Fiber ◽  
Cycle Progression ◽  
Adenovirus E1a

ABSTRACT Rho GTPases are major regulators of cytoskeletal dynamics, but they also affect cell proliferation, transformation, and oncogenesis. RhoE, a member of the Rnd subfamily that does not detectably hydrolyze GTP, inhibits RhoA/ROCK signaling to promote actin stress fiber and focal adhesion disassembly. We have generated fibroblasts with inducible RhoE expression to investigate the role of RhoE in cell proliferation. RhoE expression induced a loss of stress fibers and cell rounding, but these effects were only transient. RhoE induction inhibited cell proliferation and serum-induced S-phase entry. Neither ROCK nor RhoA inhibition accounted for this response. Consistent with its inhibitory effect on cell cycle progression, RhoE expression was induced by cisplatin, a DNA damage-inducing agent. RhoE-expressing cells failed to accumulate cyclin D1 or p21cip1 protein or to activate E2F-regulated genes in response to serum, although ERK, PI3-K/Akt, FAK, Rac, and cyclin D1 transcription was activated normally. The expression of proteins that bypass the retinoblastoma (pRb) family cell cycle checkpoint, including human papillomavirus E7, adenovirus E1A, and cyclin E, rescued cell cycle progression in RhoE-expressing cells. RhoE also inhibited Ras- and Raf-induced fibroblast transformation. These results indicate that RhoE inhibits cell cycle progression upstream of the pRb checkpoint.

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.

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