A study for the mechanism of progression of cell differentiation in osteoblast with ionizing radiation : Involvement of activation of signal transduction in cells.

电离辐射成骨细胞分化进展机制的研究：细胞信号转导激活的参与。

• 批准号: 08877284
• 负责人: HACHISU Reiko
• 金额: $ 1.28万
• 依托单位: Showa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Exploratory Research
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08877284/
• 关键词: Radiation effect; Osteoblasts; Signal transduction; Cell differentiation

We investigated a mechanism for progression of cell differentiation by free radicals formed with ionizing radiation. As the activation of signal transduction is possibly involved in the progression of cell differentiation with radiation, we used inhibitors of signal transduction to investigate the mechanism.1.MC3T3-E1 cells, an osteoblast-like cell line, were irradiated with x-ray with 10 Gy on culture day3. Alkalinphosphatase (ALP) activity, one of differentiation marker, in the cells was increased from culture day 12.2.Addition of 50 mM Genistein, a tyrosine kinase inhibitor, slightly increased ALP specific activity in non-irradiated cells. On the other hand, in irradiated cells, increase of ALP specific activity after irradiation was inhibited by Genistein, showing comparable activity to non-irradiated control cells. Therefore, Genistein showed a possibility to inhibit the increase of ALP specific activity by the irradiation. 3.Fifty mM H-7, a non-specific serin/threonin kinase inhibitor, inhibited the increase of ALP specific activity after irradiation, while protein kinase C specific inhibitor of Calphostin C at 0.1 mM did not. 4.Neomycin, a phospholipase C inhibitor, also did not affect the increase of ALP specific activity in irradiated cells.The results suggest a possibility that increase of ALP activity in MC3T3-E1 cells induced by the x-ray irradiation is consequence of activation of tyrosine kinase in signal transduction of the cells. Furthermore, activation of serin/threonin kinases such as protein kinase A other than protein kinase C is possibly incorporated for the increase of ALP activity after irradiation.

我们研究了电离辐射形成的自由基促进细胞分化的机制。由于信号转导的激活可能参与了辐射诱导细胞分化的过程，我们使用信号转导抑制剂来研究其机制。1.用10戈伊的X射线照射培养第3天的成骨样细胞系MC 3 T3-E1细胞。从培养第12.2天开始，细胞中分化标志物之一碱性磷酸酶（ALP）活性开始升高。加入50 mM酪氨酸激酶抑制剂Genistein，未照射细胞中ALP比活性略有升高。另一方面，在照射后的细胞中，ALP比活性的增加被染料木黄酮抑制，显示出与未照射的对照细胞相当的活性。因此，染料木黄酮有可能抑制辐射引起的ALP比活性的升高。3. 50 mM H-7，一种非特异性丝氨酸/苏氨酸激酶抑制剂，抑制照射后ALP比活性的增加，而0.1 mM的Calphostin C的蛋白激酶C特异性抑制剂没有。4.磷脂酶C抑制剂新霉素对照射后细胞ALP活性的增加无明显影响，提示X射线照射后细胞ALP活性的增加可能是细胞信号转导中酪氨酸激酶激活的结果。此外，除了蛋白激酶C之外，还可能掺入了丝氨酸/苏氨酸激酶如蛋白激酶A的活化，以增加照射后的ALP活性。