High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells
Period2 is a core circadian gene, which not only maintains the circadian rhythm of cells but also regulates some organic functions. We investigated the effects of mPeriod2 (mPer2) expression on radiosensitivity in normal mouse cells exposed to 60Co-γ-rays. NIH 3T3 cells were treated with 12...
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Associação Brasileira de Divulgação Científica
2009-10-01
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doaj-a7c86713d25f4c6db3690ffefd264f952020-11-24T22:21:25ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2009-10-014210882891High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cellsL. ChangY.Y. LiuB. ZhuY. LiH. HuaY.H. WangJ. ZhangZ. JiangZ.R. WangPeriod2 is a core circadian gene, which not only maintains the circadian rhythm of cells but also regulates some organic functions. We investigated the effects of mPeriod2 (mPer2) expression on radiosensitivity in normal mouse cells exposed to 60Co-γ-rays. NIH 3T3 cells were treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) to induce endogenous mPer2 expression or transfected with pcDNA3.1(+)-mPer2 and irradiated with 60Co-γ-rays, and then analyzed by several methods such as flow cytometry, colony formation assay, RT-PCR, and immunohistochemistry. Flow cytometry and colony formation assay revealed that irradiated NIH 3T3 cells expressing high levels of mPer2 showed a lower death rate (TPA: 24 h 4.3% vs 12 h 6.8% and control 9.4%; transfection: pcDNA3.1-mPer2 3.7% vs pcDNA3.1 11.3% and control 8.2%), more proliferation and clonogenic survival (TPA: 121.7 ± 6.51 vs 66.0 ± 3.51 and 67.7 ± 7.37; transfection: 121.7 ± 6.50 vs 65.3 ± 3.51 and 69.0 ± 4.58) both when treated with TPA and transfected with mPer2. RT-PCR analysis showed an increased expression of bax, bcl-2, p53, c-myc, mre11, and nbs1, and an increased proportionality of bcl-2/bax in the irradiated cells at peak mPer2 expression compared with cells at trough mPer2 expression and control cells. However, no significant difference in rad50 expression was observed among the three groups of cells. Immunohistochemistry also showed increased protein levels of P53, BAX and proliferating cell nuclear antigen in irradiated cells with peak mPer2 levels. Thus, high expression of the circadian gene mPer2 may reduce the radiosensitivity of NIH 3T3 cells. For this effect, mPer2 may directly or indirectly regulate the expressions of cell proliferation- and apoptosis-related genes and DNA repair-related genes.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001000003CircadianmPer2RadiationCell deathProliferationDNA repair |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
L. Chang Y.Y. Liu B. Zhu Y. Li H. Hua Y.H. Wang J. Zhang Z. Jiang Z.R. Wang |
spellingShingle |
L. Chang Y.Y. Liu B. Zhu Y. Li H. Hua Y.H. Wang J. Zhang Z. Jiang Z.R. Wang High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells Brazilian Journal of Medical and Biological Research Circadian mPer2 Radiation Cell death Proliferation DNA repair |
author_facet |
L. Chang Y.Y. Liu B. Zhu Y. Li H. Hua Y.H. Wang J. Zhang Z. Jiang Z.R. Wang |
author_sort |
L. Chang |
title |
High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells |
title_short |
High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells |
title_full |
High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells |
title_fullStr |
High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells |
title_full_unstemmed |
High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells |
title_sort |
high expression of the circadian gene mper2 diminishes the radiosensitivity of nih 3t3 cells |
publisher |
Associação Brasileira de Divulgação Científica |
series |
Brazilian Journal of Medical and Biological Research |
issn |
0100-879X 1414-431X |
publishDate |
2009-10-01 |
description |
Period2 is a core circadian gene, which not only maintains the circadian rhythm of cells but also regulates some organic functions. We investigated the effects of mPeriod2 (mPer2) expression on radiosensitivity in normal mouse cells exposed to 60Co-γ-rays. NIH 3T3 cells were treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) to induce endogenous mPer2 expression or transfected with pcDNA3.1(+)-mPer2 and irradiated with 60Co-γ-rays, and then analyzed by several methods such as flow cytometry, colony formation assay, RT-PCR, and immunohistochemistry. Flow cytometry and colony formation assay revealed that irradiated NIH 3T3 cells expressing high levels of mPer2 showed a lower death rate (TPA: 24 h 4.3% vs 12 h 6.8% and control 9.4%; transfection: pcDNA3.1-mPer2 3.7% vs pcDNA3.1 11.3% and control 8.2%), more proliferation and clonogenic survival (TPA: 121.7 ± 6.51 vs 66.0 ± 3.51 and 67.7 ± 7.37; transfection: 121.7 ± 6.50 vs 65.3 ± 3.51 and 69.0 ± 4.58) both when treated with TPA and transfected with mPer2. RT-PCR analysis showed an increased expression of bax, bcl-2, p53, c-myc, mre11, and nbs1, and an increased proportionality of bcl-2/bax in the irradiated cells at peak mPer2 expression compared with cells at trough mPer2 expression and control cells. However, no significant difference in rad50 expression was observed among the three groups of cells. Immunohistochemistry also showed increased protein levels of P53, BAX and proliferating cell nuclear antigen in irradiated cells with peak mPer2 levels. Thus, high expression of the circadian gene mPer2 may reduce the radiosensitivity of NIH 3T3 cells. For this effect, mPer2 may directly or indirectly regulate the expressions of cell proliferation- and apoptosis-related genes and DNA repair-related genes. |
topic |
Circadian mPer2 Radiation Cell death Proliferation DNA repair |
url |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001000003 |
work_keys_str_mv |
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