The serine/threonine kinase CHK2 is a keycomponent of the DNA damage response. In human cells, following genotoxic stress, CHK2 is activated and phosphorylates 〉20 proteins to induce the appropriate cellular response...The serine/threonine kinase CHK2 is a keycomponent of the DNA damage response. In human cells, following genotoxic stress, CHK2 is activated and phosphorylates 〉20 proteins to induce the appropriate cellular response, which, depending on the extent of damage, the cell type, and other factors, could be cell cycle checkpoint activation, induction of apoptosis or senescence, DNA repair, or tolerance of the damage. Recently, CHK2 has also been found to have cellular functions independent of the presence of nuclear DNA lesions. In par- ticular, CHK2 participates in several molecular processes involved in DNA structure modification and cell cycle progression. In this review, we discuss the activity of CHK2 in response to DNA damage and in the maintenance of the biological functions in unstressed cells. These activities are also considered in relation to a possible role of CHK2 in tumorigenesis and, as a consequence, as a target of cancer therapy.展开更多
To explore the role of the Chk2 protein expression and DNA double strand breaks (DSBs) repair in low dose hyper-radiosensitivity (HRS)/increased radioresistance (IRR) of non-small cell lung cancer,A549 cells were subj...To explore the role of the Chk2 protein expression and DNA double strand breaks (DSBs) repair in low dose hyper-radiosensitivity (HRS)/increased radioresistance (IRR) of non-small cell lung cancer,A549 cells were subjected to irradiation at the dosage ranging from 0.05-2 Gy.Clonogenic survival was measured by using fluorescence-activated cell sorting (FACS) plating technique.Percentage of cells in M-phase after low doses of X-irradiation was evaluated by phospho-histone H3-FITC/PI and Western blotting was used to detect protein expression of Chk2 and phospo-Chk2.DNA DSBs repair efficiency was also measured by induction and persistence of γ-H2AX.The results showed that the killing ability of irradiation with A549 cells increased at low conditioning dose below 0.3 Gy.Within the dose of 0.3 to 0.5 Gy,A549 cells showed a certain extent of radiation resistance.And when the dose was more than 0.5 Gy,survival fraction exhibited a negative correlation with the dosage.There was no difference between the 0.1 or 0.2 Gy dosage groups and the un-irradiated group in terms of the percentage of cells in M phase.But in the high dosage group (0.3-1.0 Gy),the percentage of cells in M phase was decreased markedly.In addition,the percentage of cells in M phase began to decrease two hours after irradiation.One hour after irradiation,there was no conspicuous activation of Chk2 kinase in 0.1 or 0.2 Gy group,but when the irradiation dose reached 0.3 Gy or higher,Chk2 kinase started to be activated and the activation level showed no significant difference among high dosage groups (0.4,0.5,1.0 Gy).Within 1 to 6 h,the DNA DSBs repair efficiency was decreased at 0.2 Gy but increased at 0.5 Gy and 1.0 Gy,which was in line with Chk2 activation.We are led to conclude that the mechanism of HRS/IRR in A549 cell line was probably due to early G2/M checkpoint arrest and enhanced DNA DSBs repair.In this regard,Chk2 activation plays a key role in G2/M checkpoint activation.展开更多
目的:探讨检测点激酶2(check point kinase2,Chk2)和重构剪切因子1(remodeling and spacing factor1,Rsf1)在卵巢浆液性腺癌(ovarian serous adenocarcinoma,OSA)中表达及其临床意义。方法:采用免疫组化SP法检测58例高级别OSA、14例低级...目的:探讨检测点激酶2(check point kinase2,Chk2)和重构剪切因子1(remodeling and spacing factor1,Rsf1)在卵巢浆液性腺癌(ovarian serous adenocarcinoma,OSA)中表达及其临床意义。方法:采用免疫组化SP法检测58例高级别OSA、14例低级别OSA中Chk2和Rsf1蛋白的表达水平,分析与临床病理参数的关系。并检测27例卵巢交界性浆液性肿瘤(ovarian borderline serous tumor,OBST)中两种蛋白的表达水平,与OSA进行对比分析。结果:Chk2在高级别和低级别OSA中阳性率分别为79.3%(46/58)和50.0%(7/14),差异有统计学意义,χ2=4.99,P=0.026;在OSA和OBST中阳性率分别为77.8%(56/72)和44.4%(12/27),差异有统计学意义,χ2=7.41,P=0.006。Chk2的表达与OSA复发及3年生存期有相关性,P<0.05;而与年龄、肿瘤最大径、淋巴结有无转移、发病部位及pTNM分期无关,P>0.05。Rsf1在高级别和低级别OSA中阳性率分别为86.2%(50/58)和57.1%(8/14),差异有统计学意义,χ2=6.08,P=0.023;在OSA及OBST中阳性率分别为79.2%(57/72)和51.9%(14/27),差异有统计学意义,χ2=8.16,P=0.004。Rsf1的表达与OSA复发及pTNM分期有相关性,P<0.05;而与年龄、肿瘤大小、淋巴结有无转移、发病部位及3年生存期无关,P>0.05。Chk2和Rsf1的表达存在明显相关性,r=0.343,P=0.003。结论:Chk2与Rsf1在OSA的发生发展中起重要作用,可作为临床指导治疗和评价患者预后的重要标志。展开更多
文摘The serine/threonine kinase CHK2 is a keycomponent of the DNA damage response. In human cells, following genotoxic stress, CHK2 is activated and phosphorylates 〉20 proteins to induce the appropriate cellular response, which, depending on the extent of damage, the cell type, and other factors, could be cell cycle checkpoint activation, induction of apoptosis or senescence, DNA repair, or tolerance of the damage. Recently, CHK2 has also been found to have cellular functions independent of the presence of nuclear DNA lesions. In par- ticular, CHK2 participates in several molecular processes involved in DNA structure modification and cell cycle progression. In this review, we discuss the activity of CHK2 in response to DNA damage and in the maintenance of the biological functions in unstressed cells. These activities are also considered in relation to a possible role of CHK2 in tumorigenesis and, as a consequence, as a target of cancer therapy.
基金supported by a grant from a Key ScientificResearch Program of Hubei Provincial Authorities (No.JX2A11)
文摘To explore the role of the Chk2 protein expression and DNA double strand breaks (DSBs) repair in low dose hyper-radiosensitivity (HRS)/increased radioresistance (IRR) of non-small cell lung cancer,A549 cells were subjected to irradiation at the dosage ranging from 0.05-2 Gy.Clonogenic survival was measured by using fluorescence-activated cell sorting (FACS) plating technique.Percentage of cells in M-phase after low doses of X-irradiation was evaluated by phospho-histone H3-FITC/PI and Western blotting was used to detect protein expression of Chk2 and phospo-Chk2.DNA DSBs repair efficiency was also measured by induction and persistence of γ-H2AX.The results showed that the killing ability of irradiation with A549 cells increased at low conditioning dose below 0.3 Gy.Within the dose of 0.3 to 0.5 Gy,A549 cells showed a certain extent of radiation resistance.And when the dose was more than 0.5 Gy,survival fraction exhibited a negative correlation with the dosage.There was no difference between the 0.1 or 0.2 Gy dosage groups and the un-irradiated group in terms of the percentage of cells in M phase.But in the high dosage group (0.3-1.0 Gy),the percentage of cells in M phase was decreased markedly.In addition,the percentage of cells in M phase began to decrease two hours after irradiation.One hour after irradiation,there was no conspicuous activation of Chk2 kinase in 0.1 or 0.2 Gy group,but when the irradiation dose reached 0.3 Gy or higher,Chk2 kinase started to be activated and the activation level showed no significant difference among high dosage groups (0.4,0.5,1.0 Gy).Within 1 to 6 h,the DNA DSBs repair efficiency was decreased at 0.2 Gy but increased at 0.5 Gy and 1.0 Gy,which was in line with Chk2 activation.We are led to conclude that the mechanism of HRS/IRR in A549 cell line was probably due to early G2/M checkpoint arrest and enhanced DNA DSBs repair.In this regard,Chk2 activation plays a key role in G2/M checkpoint activation.
