scholarly journals Effects of HMGB-1 Overexpression on Cell-Cycle Progression in MCF-7 Cells

2004 ◽  
Vol 19 (3) ◽  
pp. 321 ◽  
Author(s):  
Sarah Yoon ◽  
Jin Young Lee ◽  
Byung-Koo Yoon ◽  
DukSoo Bae ◽  
DooSeok Choi
2017 ◽  
Vol 41 (6) ◽  
pp. 2268-2278 ◽  
Author(s):  
Yu Li ◽  
Yong Cui ◽  
Wenxue Wang ◽  
Mingxing Ma ◽  
Meizhang Li ◽  
...  

Background/Aims: The serum inhibited gene (Si1) was named according to its inhibited expression in response to serum exposure. Si1 has an important relationship with tumors. Autophagy and apoptosis are two types of cell death. However, there are few studies regarding the association between Si1 and autophagy, or apoptosis in tumors. In this, we investigated the effect of Si1 on the proliferation and cell cycle progression of MCF-7 cells and its influence on autophagy and apoptosis in MCF-7 cells. Methods: To investigate these functions of Si1 in tumor cells, we firstly constructed a pEGFP-Si1 overexpression vector and a pSilencer-Si1 interference vector, and we subsequently tested the proliferation and cell cycle progression of MCF-7 cells using the MTT assay and flow cytometry, and we then detected autophagy by western blotting and MDC (Monodansylcadaverine) staining as well as apoptosis by western blotting and Hoechst 33258 staining. Results: We found that the Si1 gene can significantly inhibit the viability of MCF-7 cells and arrest the cell cycle at the G2/M phase. Si1 can induce autophagy through upregulation of LC3-II and Beclin1, it can induce apoptosis through cleavage of PARP in MCF-7 cells. Conclusion: Altogether, our study indicated that Si1 can inhibit cell proliferation of MCF-7, and also induces autophagy and apoptosis. This study firstly investigated the effect of Si1 on autophagy and apoptosis in MCF-7 cells. Moreover, it also improves the current understanding of the mechanisms related to the effect of Si1 on tumor cells and also provides a foundation for gene-targeted therapy.


2004 ◽  
Vol 287 (1) ◽  
pp. C125-C134 ◽  
Author(s):  
Halima Ouadid-Ahidouch ◽  
Morad Roudbaraki ◽  
Philippe Delcourt ◽  
Ahmed Ahidouch ◽  
Nathalie Joury ◽  
...  

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.


2001 ◽  
Vol 27 (3) ◽  
pp. 293-307 ◽  
Author(s):  
JS Lewis ◽  
TJ Thomas ◽  
CM Klinge ◽  
MA Gallo ◽  
T Thomas

It has been suggested that alterations in estradiol (E(2)) metabolism, resulting in increased production of 16alpha-hydroxyestrone (16alpha-OHE(1)), is associated with an increased risk of breast cancer. In the present study, we examined the effects of 16alpha-OHE(1)on DNA synthesis, cell cycle progression, and the expression of cell cycle regulatory genes in MCF-7 breast cancer cells. G(1) synchronized cells were treated with 1 to 25 nM 16alpha-OHE(1) for 24 and 48 h. [(3)H]Thymidine incorporation assay showed that 16alpha-OHE(1) caused an 8-fold increase in DNA synthesis compared with that of control cells, whereas E(2) caused a 4-fold increase. Flow cytometric analysis of cell cycle progression also demonstrated the potency of 16alpha-OHE(1) in stimulating cell growth. When G(1) synchronized cells were treated with 10 nM 16alpha-OHE(1) for 24 h, 62+/-3% of cells were in S phase compared with 14+/-3% and 52+/-2% of cells in the control and E(2)-treated groups respectively. In order to explore the role of 16alpha-OHE(1) in cell cycle regulation, we examined its effects on cyclins (D1, E, A, B1), cyclin dependent kinases (Cdk4, Cdk2), and retinoblastoma protein (pRB) using Western and Northern blot analysis. Treatment of cells with 10 nM 16alpha-OHE(1) resulted in 4- and 3-fold increases in cyclin D1 and cyclin A, respectively, at the protein level. There was also a significant increase in pRB phosphorylation and Cdk2 activation. In addition, transient transfection assay using an estrogen response element-driven luciferase reporter vector showed a 15-fold increase in estrogen receptor-mediated transactivation compared with control. These results show that 16alpha-OHE(1) is a potent estrogen capable of accelerating cell cycle kinetics and stimulating the expression of cell cycle regulatory proteins.


2001 ◽  
Vol 21 (3) ◽  
pp. 794-810 ◽  
Author(s):  
James S. Foster ◽  
Donald C. Henley ◽  
Antonin Bukovsky ◽  
Prem Seth ◽  
Jay Wimalasena

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.


2017 ◽  
Vol 281 ◽  
pp. 139-151 ◽  
Author(s):  
Ka Yiu Yip ◽  
Murphy Lam Yim Wan ◽  
Alice Sze Tsai Wong ◽  
Kenneth S. Korach ◽  
Hani El-Nezami

2003 ◽  
Vol 106 (5) ◽  
pp. 789-798 ◽  
Author(s):  
Sophie F. Doisneau-Sixou ◽  
Philippe Cestac ◽  
Jean-Charles Faye ◽  
Gilles Favre ◽  
Robert L. Sutherland

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