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
diabetes mellitus(DM)is a disease syndrome characterized by chronic hyperglycaemia.A long-term high-glucose environment leads to reactive oxygen species(ROS)production and nuclear DNA damage.human umbilical cord mesen...diabetes mellitus(DM)is a disease syndrome characterized by chronic hyperglycaemia.A long-term high-glucose environment leads to reactive oxygen species(ROS)production and nuclear DNA damage.human umbilical cord mesenchymal stem cell(HUcMSC)infusion induces significant antidiabetic effects in type 2 diabetes mellitus(T2DM)rats.Insulin-like growth factor 1(IGF1)receptor(IGF1R)is important in promoting glucose metabolism in diabetes;however,the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear.In this study,a DM rat model was induced with high-fat diet feeding and streptozotocin(STZ)administration and rats were infused four times with HUcMSC.Blood glucose,interleukin-6(IL-6),IL-10,glomerular basement membrane,and renal function were examined.Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays.The expression of IGF1R,phosphorylated checkpoint kinase 2(p-CHK2),and phosphorylated protein 53(p-p53)was examined using immunohistochemistry(IHC)and western blot analysis.Enzyme-linked immunosorbent assay(ELISA)was used to determine the serum levels of 8-hydroxydeoxyguanosine(8-OHdG).Flow cytometry experiments were used to detect the surface markers of HUcMSC.The identification of the morphology and phenotype of HUcMSC was performed by way of oil red“O”staining and Alizarin red staining.DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane,increased the expression of IGF1 and IGF1R.IGF1R interacted with CHK2,and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells.When cisplatin was used to induce DNA damage,the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment.HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats.The expression of IGF1,IGF1R,p-CHK2,and p-p53,and the level of 8-OHdG in the DM group increased significantly compared with those in the control group,and decreased after HUcMSC treatment.Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage.HUcMSC infusion protected against kidney injury in DM rats.The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.展开更多
Background Checkpoint kinase 2 （CHK2） is a DNA damage-activated protein kinase which is involved in cell cycle checkpoint control, CHK2 gene could be a candidate gene for colorectal cancer susceptibility, But there ...Background Checkpoint kinase 2 （CHK2） is a DNA damage-activated protein kinase which is involved in cell cycle checkpoint control, CHK2 gene could be a candidate gene for colorectal cancer susceptibility, But there are few systematic reports on mutation of CHK2 in colorectal cancer. Methods The mutations of all 14 exons of CHK2 in 56 colorectal cancer cell lines were screened systematically, using denaturing high-performance liquid chromatography （DHPLC） to screen the mismatches of the CHK2 exons amplified products, and then the suspected mutant cell lines were scanned by nucleotide sequence analysis. Results VACO400 in CHK2 exon la was suspected to have mutation by DHPLC and confirmed by sequence, but this was nonsense mutation. C106, CX-1, HT-29, SK01, SW480, SW620 and VACO400 in CHK2 exon lb were confirmed to have the same nonsense mutation in 11609 A〉G. DLD-1 and HCT-15 in CHK2 exon 2 were confirmed to have missense mutation R145W, which was heterozygous C〉T missense mutation at nucleotide 433, leading to an Arg〉Trp substitution within the FHA domain. Conclusions The CHK2 mutation in colorectal cancer is a low frequency event, There are just 10 cell lines to have sequence variations in all the 14 exons in 56 colorectal cancer cell lines and only DLD-1/HCT-15 had heterozygous missense mutation. These findings may give useful information of susceptibility of colorectal cancer as single nucleotide polvmorphvsim.展开更多
Biliary tract cancers(BTC)are frequently identified at late stages and have a poor prognosis due to limited systemic treatment regimens.For more than a decade,the combination of gemcitabine and cis-platin has served a...Biliary tract cancers(BTC)are frequently identified at late stages and have a poor prognosis due to limited systemic treatment regimens.For more than a decade,the combination of gemcitabine and cis-platin has served as the first-line standard treatment.There are few choices for second-line chemo-therapy.Targeted treatment with fibroblast growth factor receptor 2 inhibitors,neurotrophic tyrosine receptor kinase inhibitors,and isocitrate dehydrogenase 1 inhibitors has had important results.Immune checkpoint inhibitors(ICI)such as pembrolizumab are only used in first-line treatment for microsatellite instability high patients.The TOPAZ-1 trial's outcome is encouraging,and there are several trials underway that might soon put targeted treatment and ICI combos into first-line options.Newer targets and agents for existing goals are being studied,which may represent a paradigm shift in BTC management.Due to a scarcity of targetable mutations and the higher toxicity profile of the current medications,the new category of drugs may occupy a significant role in BTC therapies.展开更多
Targeting androgen receptor(AR)has shown great therapeutic potential in triple-negative breast cancer(TNBC),yet its efficacy remains unsatisfactory.Here,we aimed to identify promising targeted agents that synergize wi...Targeting androgen receptor(AR)has shown great therapeutic potential in triple-negative breast cancer(TNBC),yet its efficacy remains unsatisfactory.Here,we aimed to identify promising targeted agents that synergize with enzalutamide,a second-generation AR inhibitor,in TNBC.By using a strategy for screening drug combinations based on the Sensitivity Index(SI),we found that MK-8776,a selective checkpoint kinase1(CHK1)inhibitor,showed favorable synergism with enzalutamide in AR-positive TNBC.The combination of enzalutamide and MK-8776 was found to exert more significant anti-tumor effects in TNBC than the single application of enzalutamide or MK-8776,respectively.Furthermore,a nanoparticle-based on hyaluronic acid(HA)-modified hollow-manganese dioxide(HMnO_(2)),named HMnE&M@H,was established to encapsulate and deliver enzalutamide and MK-8776.This HA-modified nanosystem managed targeted activation via pH/glutathione responsiveness.HMnE&M@H repressed tumor growth more obviously than the simple addition of enzalutamide and MK-8776 without a carrier.Collectively,our study elucidated the synergy of enzalutamide and MK-8776 in TNBC and developed a novel tumor-targeted nano drug delivery system HMnE&M@H,providing a potential therapeutic approach for the treatment of TNBC.展开更多
目的观察ATM蛋白激酶-检测点激酶2(ATM-Chk2)通路在氟抑制大鼠曲细精管上皮支持细胞增殖中的作用。方法将18日龄SPF级雄性SD大鼠曲细精管上皮支持细胞分别暴露于含0(对照)、0.25、0.50、1.00、2.00、4.00 mmol/L氟化钠的血清培养基。分...目的观察ATM蛋白激酶-检测点激酶2(ATM-Chk2)通路在氟抑制大鼠曲细精管上皮支持细胞增殖中的作用。方法将18日龄SPF级雄性SD大鼠曲细精管上皮支持细胞分别暴露于含0(对照)、0.25、0.50、1.00、2.00、4.00 mmol/L氟化钠的血清培养基。分别于染毒24、48、72 h,采用MTT法测定支持细胞的增殖情况;于染毒24 h,采用实时荧光定量PCR技术检测支持细胞内ATM、Chk2 m RNA的表达水平。结果与对照组比较,染毒24、48、72 h时,4.00 mmol/L氟化钠染毒组大鼠曲细精管上皮支持细胞的抑制率均较高,差异有统计学意义(P<0.05);且随着氟化钠染毒剂量的升高和染毒时间的延长,氟对曲细精管上皮支持细胞的抑制率均呈上升趋势。与对照组比较,1、2 mmol/L氟化钠染毒组曲细精管上皮支持细胞ATM和Chk2 m RNA的表达水平均升高,而4 mmol/L氟化钠染毒组ATM和Chk2 m RNA的表达水平均降低,差异有统计学意义(P<0.05);且随着氟化钠染毒剂量的升高,曲细精管上皮支持细胞ATM、Chk2 m RNA的表达水平均呈下降趋势。结论不同剂量氟抑制生殖细胞增殖可能是通过干扰曲细精管上皮支持细胞中DNA损伤检验点ATM、Chk2的表达而实现的。展开更多
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.
基金supported by the Peak Disciplines(Type IV)of Institutions of Higher Learning in Shanghai,the Discipline Leader Program of Pudong New District Health and Family Planning Commission(No.PWRd2018-02)the Natural Science Foundation of Jiangxi Province(Nos.20181ACB20021 and 20181BAB205044),China.
文摘diabetes mellitus(DM)is a disease syndrome characterized by chronic hyperglycaemia.A long-term high-glucose environment leads to reactive oxygen species(ROS)production and nuclear DNA damage.human umbilical cord mesenchymal stem cell(HUcMSC)infusion induces significant antidiabetic effects in type 2 diabetes mellitus(T2DM)rats.Insulin-like growth factor 1(IGF1)receptor(IGF1R)is important in promoting glucose metabolism in diabetes;however,the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear.In this study,a DM rat model was induced with high-fat diet feeding and streptozotocin(STZ)administration and rats were infused four times with HUcMSC.Blood glucose,interleukin-6(IL-6),IL-10,glomerular basement membrane,and renal function were examined.Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays.The expression of IGF1R,phosphorylated checkpoint kinase 2(p-CHK2),and phosphorylated protein 53(p-p53)was examined using immunohistochemistry(IHC)and western blot analysis.Enzyme-linked immunosorbent assay(ELISA)was used to determine the serum levels of 8-hydroxydeoxyguanosine(8-OHdG).Flow cytometry experiments were used to detect the surface markers of HUcMSC.The identification of the morphology and phenotype of HUcMSC was performed by way of oil red“O”staining and Alizarin red staining.DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane,increased the expression of IGF1 and IGF1R.IGF1R interacted with CHK2,and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells.When cisplatin was used to induce DNA damage,the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment.HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats.The expression of IGF1,IGF1R,p-CHK2,and p-p53,and the level of 8-OHdG in the DM group increased significantly compared with those in the control group,and decreased after HUcMSC treatment.Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage.HUcMSC infusion protected against kidney injury in DM rats.The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.
基金China-Korea Young Scientist Exchange Program(2004), Biomedical Research Institute of Kyungpook National University Hospital.
文摘Background Checkpoint kinase 2 （CHK2） is a DNA damage-activated protein kinase which is involved in cell cycle checkpoint control, CHK2 gene could be a candidate gene for colorectal cancer susceptibility, But there are few systematic reports on mutation of CHK2 in colorectal cancer. Methods The mutations of all 14 exons of CHK2 in 56 colorectal cancer cell lines were screened systematically, using denaturing high-performance liquid chromatography （DHPLC） to screen the mismatches of the CHK2 exons amplified products, and then the suspected mutant cell lines were scanned by nucleotide sequence analysis. Results VACO400 in CHK2 exon la was suspected to have mutation by DHPLC and confirmed by sequence, but this was nonsense mutation. C106, CX-1, HT-29, SK01, SW480, SW620 and VACO400 in CHK2 exon lb were confirmed to have the same nonsense mutation in 11609 A〉G. DLD-1 and HCT-15 in CHK2 exon 2 were confirmed to have missense mutation R145W, which was heterozygous C〉T missense mutation at nucleotide 433, leading to an Arg〉Trp substitution within the FHA domain. Conclusions The CHK2 mutation in colorectal cancer is a low frequency event, There are just 10 cell lines to have sequence variations in all the 14 exons in 56 colorectal cancer cell lines and only DLD-1/HCT-15 had heterozygous missense mutation. These findings may give useful information of susceptibility of colorectal cancer as single nucleotide polvmorphvsim.
文摘Biliary tract cancers(BTC)are frequently identified at late stages and have a poor prognosis due to limited systemic treatment regimens.For more than a decade,the combination of gemcitabine and cis-platin has served as the first-line standard treatment.There are few choices for second-line chemo-therapy.Targeted treatment with fibroblast growth factor receptor 2 inhibitors,neurotrophic tyrosine receptor kinase inhibitors,and isocitrate dehydrogenase 1 inhibitors has had important results.Immune checkpoint inhibitors(ICI)such as pembrolizumab are only used in first-line treatment for microsatellite instability high patients.The TOPAZ-1 trial's outcome is encouraging,and there are several trials underway that might soon put targeted treatment and ICI combos into first-line options.Newer targets and agents for existing goals are being studied,which may represent a paradigm shift in BTC management.Due to a scarcity of targetable mutations and the higher toxicity profile of the current medications,the new category of drugs may occupy a significant role in BTC therapies.
基金supported by the Key INTERNATIONAL COOPERATION of the National Natural Science Foundation of China(No.81920108029,China)the Key Foundation for Social Development Project of the Jiangsu Province,China(No.BE2021741,China).
文摘Targeting androgen receptor(AR)has shown great therapeutic potential in triple-negative breast cancer(TNBC),yet its efficacy remains unsatisfactory.Here,we aimed to identify promising targeted agents that synergize with enzalutamide,a second-generation AR inhibitor,in TNBC.By using a strategy for screening drug combinations based on the Sensitivity Index(SI),we found that MK-8776,a selective checkpoint kinase1(CHK1)inhibitor,showed favorable synergism with enzalutamide in AR-positive TNBC.The combination of enzalutamide and MK-8776 was found to exert more significant anti-tumor effects in TNBC than the single application of enzalutamide or MK-8776,respectively.Furthermore,a nanoparticle-based on hyaluronic acid(HA)-modified hollow-manganese dioxide(HMnO_(2)),named HMnE&M@H,was established to encapsulate and deliver enzalutamide and MK-8776.This HA-modified nanosystem managed targeted activation via pH/glutathione responsiveness.HMnE&M@H repressed tumor growth more obviously than the simple addition of enzalutamide and MK-8776 without a carrier.Collectively,our study elucidated the synergy of enzalutamide and MK-8776 in TNBC and developed a novel tumor-targeted nano drug delivery system HMnE&M@H,providing a potential therapeutic approach for the treatment of TNBC.
文摘目的观察ATM蛋白激酶-检测点激酶2(ATM-Chk2)通路在氟抑制大鼠曲细精管上皮支持细胞增殖中的作用。方法将18日龄SPF级雄性SD大鼠曲细精管上皮支持细胞分别暴露于含0(对照)、0.25、0.50、1.00、2.00、4.00 mmol/L氟化钠的血清培养基。分别于染毒24、48、72 h,采用MTT法测定支持细胞的增殖情况;于染毒24 h,采用实时荧光定量PCR技术检测支持细胞内ATM、Chk2 m RNA的表达水平。结果与对照组比较,染毒24、48、72 h时,4.00 mmol/L氟化钠染毒组大鼠曲细精管上皮支持细胞的抑制率均较高,差异有统计学意义(P<0.05);且随着氟化钠染毒剂量的升高和染毒时间的延长,氟对曲细精管上皮支持细胞的抑制率均呈上升趋势。与对照组比较,1、2 mmol/L氟化钠染毒组曲细精管上皮支持细胞ATM和Chk2 m RNA的表达水平均升高,而4 mmol/L氟化钠染毒组ATM和Chk2 m RNA的表达水平均降低,差异有统计学意义(P<0.05);且随着氟化钠染毒剂量的升高,曲细精管上皮支持细胞ATM、Chk2 m RNA的表达水平均呈下降趋势。结论不同剂量氟抑制生殖细胞增殖可能是通过干扰曲细精管上皮支持细胞中DNA损伤检验点ATM、Chk2的表达而实现的。
