Limits...
Glucocorticoid receptor and sequential P53 activation by dexamethasone mediates apoptosis and cell cycle arrest of osteoblastic MC3T3-E1 cells.

Li H, Qian W, Weng X, Wu Z, Li H, Zhuang Q, Feng B, Bian Y - PLoS ONE (2012)

Bottom Line: Glucocorticoids play a pivotal role in the proliferation of osteoblasts, but the underlying mechanism has not been successfully elucidated.It was found that the inhibitory effects were largely attributed to apoptosis and G1 phase arrest.These data demonstrate that proliferation of MC3T3-E1 cell was significantly and directly inhibited by dexamethasone treatment via aberrant GR activation and subsequently P53 activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.

ABSTRACT
Glucocorticoids play a pivotal role in the proliferation of osteoblasts, but the underlying mechanism has not been successfully elucidated. In this report, we have investigated the molecular mechanism which elucidates the inhibitory effects of dexamethasone on murine osteoblastic MC3T3-E1 cells. It was found that the inhibitory effects were largely attributed to apoptosis and G1 phase arrest. Both the cell cycle arrest and apoptosis were dependent on glucocorticoid receptor (GR), as they were abolished by GR blocker RU486 pre-treatment and GR interference. G1 phase arrest and apoptosis were accompanied with a p53-dependent up-regulation of p21 and pro-apoptotic genes NOXA and PUMA. We also proved that dexamethasone can't induce apoptosis and cell cycle arrest when p53 was inhibited by p53 RNA interference. These data demonstrate that proliferation of MC3T3-E1 cell was significantly and directly inhibited by dexamethasone treatment via aberrant GR activation and subsequently P53 activation.

Show MeSH
Dexamethasone dose-dependently inhibit MC3T3-E1 proliferation and induce cell death.(A) Proliferation of MC3T3-E1 cells was measured by CCK8 (colorimetric cell counting kit-8) after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L DEX remarkably reduced cell proliferation. B) Cell death was measured by typan blue incorporation after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L dexamethasone remarkably increased dead cell population Values are means+SEM (n = 3). *P< 0.05 vs corresponding untreated controls.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3375272&req=5

pone-0037030-g001: Dexamethasone dose-dependently inhibit MC3T3-E1 proliferation and induce cell death.(A) Proliferation of MC3T3-E1 cells was measured by CCK8 (colorimetric cell counting kit-8) after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L DEX remarkably reduced cell proliferation. B) Cell death was measured by typan blue incorporation after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L dexamethasone remarkably increased dead cell population Values are means+SEM (n = 3). *P< 0.05 vs corresponding untreated controls.

Mentions: The 24-hour exposure of murine osteoblast MC3T3-E1 to 0.001, 0.01, 0.1,1.10 µmol/L DEX respectively decreased cell proliferation in a concentration-dependent manner (Figure 1A) Compared with ethanol control and low concentration dexamethasone, 1 and 10 µmol/L DEX reduced cell proliferation by 55.01±4.01% and 60.02±6.02%, respectively. To further confirm whether DEX toxicity inhibits cell proliferation, we used Typan blue incorporation to test dead cells. Typan blue assay suggested that treatment with 1 and 10 µmol/L dexamethasone remarkably increased dead cell population to 6.10±0.00% and 7.76±0.01%, respectively (Figure 1B).


Glucocorticoid receptor and sequential P53 activation by dexamethasone mediates apoptosis and cell cycle arrest of osteoblastic MC3T3-E1 cells.

Li H, Qian W, Weng X, Wu Z, Li H, Zhuang Q, Feng B, Bian Y - PLoS ONE (2012)

Dexamethasone dose-dependently inhibit MC3T3-E1 proliferation and induce cell death.(A) Proliferation of MC3T3-E1 cells was measured by CCK8 (colorimetric cell counting kit-8) after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L DEX remarkably reduced cell proliferation. B) Cell death was measured by typan blue incorporation after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L dexamethasone remarkably increased dead cell population Values are means+SEM (n = 3). *P< 0.05 vs corresponding untreated controls.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3375272&req=5

pone-0037030-g001: Dexamethasone dose-dependently inhibit MC3T3-E1 proliferation and induce cell death.(A) Proliferation of MC3T3-E1 cells was measured by CCK8 (colorimetric cell counting kit-8) after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L DEX remarkably reduced cell proliferation. B) Cell death was measured by typan blue incorporation after cells were treated with 0, 0.001,0.01,0.1, 1.0 and 10.0 µmol/L dexamethasone for 24 hours. treatment with 1 and 10 µmol/L dexamethasone remarkably increased dead cell population Values are means+SEM (n = 3). *P< 0.05 vs corresponding untreated controls.
Mentions: The 24-hour exposure of murine osteoblast MC3T3-E1 to 0.001, 0.01, 0.1,1.10 µmol/L DEX respectively decreased cell proliferation in a concentration-dependent manner (Figure 1A) Compared with ethanol control and low concentration dexamethasone, 1 and 10 µmol/L DEX reduced cell proliferation by 55.01±4.01% and 60.02±6.02%, respectively. To further confirm whether DEX toxicity inhibits cell proliferation, we used Typan blue incorporation to test dead cells. Typan blue assay suggested that treatment with 1 and 10 µmol/L dexamethasone remarkably increased dead cell population to 6.10±0.00% and 7.76±0.01%, respectively (Figure 1B).

Bottom Line: Glucocorticoids play a pivotal role in the proliferation of osteoblasts, but the underlying mechanism has not been successfully elucidated.It was found that the inhibitory effects were largely attributed to apoptosis and G1 phase arrest.These data demonstrate that proliferation of MC3T3-E1 cell was significantly and directly inhibited by dexamethasone treatment via aberrant GR activation and subsequently P53 activation.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.

ABSTRACT
Glucocorticoids play a pivotal role in the proliferation of osteoblasts, but the underlying mechanism has not been successfully elucidated. In this report, we have investigated the molecular mechanism which elucidates the inhibitory effects of dexamethasone on murine osteoblastic MC3T3-E1 cells. It was found that the inhibitory effects were largely attributed to apoptosis and G1 phase arrest. Both the cell cycle arrest and apoptosis were dependent on glucocorticoid receptor (GR), as they were abolished by GR blocker RU486 pre-treatment and GR interference. G1 phase arrest and apoptosis were accompanied with a p53-dependent up-regulation of p21 and pro-apoptotic genes NOXA and PUMA. We also proved that dexamethasone can't induce apoptosis and cell cycle arrest when p53 was inhibited by p53 RNA interference. These data demonstrate that proliferation of MC3T3-E1 cell was significantly and directly inhibited by dexamethasone treatment via aberrant GR activation and subsequently P53 activation.

Show MeSH