Telomerase has fundamental roles in bypassing cellular aging and in cancer progression by maintaining telomere homeostasis and integrity. However, recent studies have led some investigators to suggest novel biochemica...Telomerase has fundamental roles in bypassing cellular aging and in cancer progression by maintaining telomere homeostasis and integrity. However, recent studies have led some investigators to suggest novel biochemical properties of telomerase in several essential cell signaling pathways without apparent involvement of its well established function in telomere maintenance. These observations may further enhance our understanding of the molecular actions of telomerase in aging and cancer. This review will provide an update on the extracurricular activities of telomerase in apoptosis, DNA repair, stern cell function, and in the regulation of gene expression.展开更多
Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase ...Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase activities. Cellular senescence is a safeguard program limiting the proliferative competence of cells in living organisms. Apoptosis eliminates unwanted cells by the coordinated activity of gene products that regulate and effect cell death. The intimate link between the cell cycle, cellular senes- cence, apoptosis regulation, cancer development and tumor responses to cancer treatment has become eminently apparent. Extensive research on tumor suppressor genes, oncogenes, the cell cycle and apoptosis regulatory genes has revealed how the DNA damage-sensing and -signaling pathways, referred to as the DNA-damage response network, are tied to cell proliferation, cell-cycle arrest, cellular senescence and apoptosis. DNA-damage responses are complex, involving “sensor” proteins that sense the damage, and transmit signals to “transducer” proteins, which, in turn, convey the signals to numerous “effector” proteins implicated in specific cellular pathways, including DNA repair mechanisms, cell-cycle checkpoints, cellular senescence and apoptosis. The Bcl-2 family of proteins stands among the most crucial regulators of apoptosis and performs vital functions in deciding whether a cell will live or die after cancer chemotherapy and irradiation. In addition, several studies have now revealed that members of the Bcl-2 family also interface with the cell cycle, DNA repair/recombination and cellular senescence, effects that are generally distinct from their function in apoptosis. In this review, we report progress in understanding the molecular networks that regulate cell-cycle checkpoints, cellular senescence and apoptosis after DNA damage, and discuss the influence of some Bcl-2 family members on cell-cycle checkpoint regulation.展开更多
Genomic instability remains an enabling feature of cancer and promotes malignant transformation.Alterations of DNA damage response(DDR)pathways allow genomic instability,generate neoantigens,upregulate the expression ...Genomic instability remains an enabling feature of cancer and promotes malignant transformation.Alterations of DNA damage response(DDR)pathways allow genomic instability,generate neoantigens,upregulate the expression of programmed death ligand 1(PD-L1)and interact with signaling such as cyclic GMPe AMP synthase-stimulator of interferon genes(cGASe STING)signaling.Here,we review the basic knowledge of DDR pathways,mechanisms of genomic instability induced by DDR alterations,impacts of DDR alterations on immune system,and the potential applications of DDR alterations as biomarkers and therapeutic targets in cancer immunotherapy.展开更多
The genomes of eukaryotic cells are under continuous assault by environmental agents and endogenous metabolic byproducts. Damage induced in DNA usually leads to a cascade of cellular events, the DNA damage response. F...The genomes of eukaryotic cells are under continuous assault by environmental agents and endogenous metabolic byproducts. Damage induced in DNA usually leads to a cascade of cellular events, the DNA damage response. Failure of the DNA damage response can lead to development of malignancy by reducing the efficiency and fidelity of DNA repair. The NBS1 protein is a component of the MRE11/RAD50/NBS 1 complex （MRN） that plays a critical role in the cellular response to DNA damage and the maintenance of chromosomal integrity. Mutations in the NBS1 gene are responsible for Nijmegen breakage syndrome （NBS）, a hereditary disorder that imparts an increased predisposition to development of malignancy. The phenotypic characteristics of cells isolated from NBS patients point to a deficiency in the repair of DNA double strand breaks. Here, we review the current knowledge of the role of NBS1 in the DNA damage response. Emphasis is placed on the role of NBS1 in the DNA double strand repair, modulation of the DNA damage sensing and signaling, cell cycle checkpoint control and maintenance oftelomere stability.展开更多
BRCA1 is a well-established tumor suppressor gene,which is frequently mutated in familial breast and ovarian cancers.The gene product of BRCA1 functions in a number of cellular pathways that maintain genomic stability...BRCA1 is a well-established tumor suppressor gene,which is frequently mutated in familial breast and ovarian cancers.The gene product of BRCA1 functions in a number of cellular pathways that maintain genomic stability,including DNA damage-induced cell cycle checkpoint activation,DNA damage repair,protein ubiquitination,chromatin remodeling,as well as transcriptional regulation and apoptosis.In this review,we discuss recent advances regarding our understanding of the role of BRCA1 in tumor suppression and DNA damage response,including DNA damage-induced cell cycle checkpoint activation and DNA damage repair.展开更多
Natural killer （NK） cells are a major component of the host innate immune defense against various pathogens. Several viruses, including hepatitis C virus （HCV）, have developed strategies to evade the NK-cell respo...Natural killer （NK） cells are a major component of the host innate immune defense against various pathogens. Several viruses, including hepatitis C virus （HCV）, have developed strategies to evade the NK-cell response. In our study, we found HCV infection could trigger DNA damage response by both ataxia telangiectasia mutated （ATM） and ATM- and Rad3-related （ATR） pathways. Recent reports had revealed that NKG2D ligands （NK cell- activating ligands） were upregulated when a major DNA damage checkpoint pathway was activated. However, here we found that DNA damage response was activated but NKG2D ligands were downregulated upon HCV infection. Further studies showed that the protease NS3/4A of HCV which had been shown relation with immune invasion contributed to the reduced expression of NKG2D ligands. These findings provide a novel insight into the mechanisms evolved by HCV to escape from the NK cell response. Cellular ＆ Molecular Immunology. 2008;5（6）： 475-478.展开更多
AIM： To investigate whether hepatitis B virus （HBV） infection activates DNA damage response and DNA repair cofactors inhibit HBV infection and replication. METHODS： Human hepatocyte cell line HL7702 was studied. I...AIM： To investigate whether hepatitis B virus （HBV） infection activates DNA damage response and DNA repair cofactors inhibit HBV infection and replication. METHODS： Human hepatocyte cell line HL7702 was studied. Immunoblotting was performed to test the expression of ataxia telangiectasia-mutated （ATM）- Rad3-related protein （ATR）, p21 and the level of phosphorylation of Chkl, p53, H2AX, ATM in HBV-infected or non-infected-cells. Special short RNAi oligos was transfected to induce transient ATR knockdown in HL7702. ATR-ATN chemical inhibitors caffeine （CF） and theophylline （TP）, or Chkl inhibitor 7-hydroxystaurosporine （UCN01） was studied to determine whether they suppress cellular DNA damage response and NG132 inhibits proteasome. RESULTS： The ATR checkpoint pathway, responding to single-strand breaks in DNA, was activated in response to HBV infection. ATR knockdown cells decreased the HBV DNA yields, implying that HBV infection and replication could activate and exploit the activated DNA damage response. CF/TP or UCN01 reduced the HBV DNA yield by 70% and 80%, respectively. HBV abrogated the ATR-dependent DNA damage signaling pathway by degrading p21, and introduction of the p21 protein before HBV infection reduced the HBV DNA yield. Consistent with this result, p21 accumulation after NG132 treatment also sharply decreased the HBV DNA yield. CONCLUSION： HBV infection can be treated with therapeutic approaches targeting host cell proteins by inhibiting a cellular gene required for HBV replication or by restoring a response abrogated by HBV, thus providing a potential approach to the prevention and treatment of HBV infection.展开更多
Gastric cancer remains one of the leading causes of cancer-related death worldwide,and most of the cases are associated with Helicobacter pylori infection.This bacterium promotes the production of reactive oxygen spec...Gastric cancer remains one of the leading causes of cancer-related death worldwide,and most of the cases are associated with Helicobacter pylori infection.This bacterium promotes the production of reactive oxygen species(ROS),which cause DNA damage in gastric epithelial cells.In this study,we evaluated the expression of important genes involved in the recognition of DNA damage(ATM,ATR,and H2AX)and ROS-induced damage repair(APE1)and the expression of some miRNAs(miR-15a,miR-21,miR-24,miR-421 and miR-605)that target genes involved in the DNA damage response(DDR)in 31 fresh tissues of gastric cancer.Cytoscape v3.1.1 was used to construct the postulated miRNA:mRNA interaction network.Analysis performed by real-time quantitative PCR exhibited significantly increased levels of the APE1(RQ=2.55,p<0.0001)and H2AX(RQ=2.88,p=0.0002)genes beyond the miR-421 and miR-605 in the gastric cancer samples.In addition,significantly elevated levels of miR-21,miR-24 and miR-421 were observed in diffuse-type gastric cancer.Correlation analysis reinforced some of the gene:gene(ATM/ATR/H2AX)and miRNA:mRNA relationships obtained also with the interaction network.Thus,our findings show that tumor cells from gastric cancer presents deregulation of genes and miRNAs that participate in the recognition and repair of DNA damage,which could confer an advantage to cell survival and proliferation in the tumor microenvironment.展开更多
The hematopoietic system is susceptible to ionizing radiation(IR),which can cause acute hematopoietic failure or long-term myelosuppression.As the most primitive cells of the hematopoietic hierarchy,hematopoietic stem...The hematopoietic system is susceptible to ionizing radiation(IR),which can cause acute hematopoietic failure or long-term myelosuppression.As the most primitive cells of the hematopoietic hierarchy,hematopoietic stem cells(HSCs)maintain lifelong hematopoietic homeostasis and promote hematopoietic regeneration during stress.Numerous studies have shown that nuclear and mitochondrial genomes are the main targets of radiation injury in HSCs.More importantly,the damage of DNA may trigger a series of biological responses that largely determine HSC fate following IR exposure.Although some essential pathways and factors involved in DNA injury and damage in HSCs have been revealed,a comprehensive understanding of the biological effects of radiation on HSCs still needs to be improved.This review focuses on recent insights into the molecular mechanisms underlying DNA damage and repair in HSCs after IR.Then summarize corresponding regulatory measures,which may provide a reference for further research in this field.展开更多
Glioblastoma multiforme （GBM） is the most aggressive primary brain tumor in adults.Current therapy includes surgery,radiation and chemotherapy with temozolomide （TMZ）.Major determinants of clinical response to TMZ...Glioblastoma multiforme （GBM） is the most aggressive primary brain tumor in adults.Current therapy includes surgery,radiation and chemotherapy with temozolomide （TMZ）.Major determinants of clinical response to TMZ include methylation status of the O6-methylguanine-DNA methyltransferase （MGMT） promoter and mismatch repair （MMR） status.Though the MGMT promoter is methylated in 45% of cases,for the first nine months of follow-up,TMZ does not change survival outcome.Furthermore,MMR deficiency makes little contribution to clinical resistance,suggesting that there exist unrecognized mechanisms of resistance.We generated paired GBM cell lines whose resistance was attributed to neither MGMT nor MMR.We show that,responding to TMZ,these cells exhibit a decoupling of DNA damage response （DDR） from ongoing DNA damages.They display methylation-resistant synthesis in which ongoing DNA synthesis is not inhibited.They are also defective in the activation of the S and G2 phase checkpoint.DDR proteins ATM,Chk2,MDC1,NBS1 and gammaH2AX also fail to form discrete foci.These results demonstrate that failure of DDR may play an active role in chemoresistance to TMZ.DNA damages by TMZ are repaired by MMR proteins in a futile,reiterative process,which activates DDR signaling network that ultimately leads to the onset of cell death.GBM cells may survive genetic insults in the absence of DDR.We anticipate that our findings will lead to more studies that seek to further define the role of DDR in ultimately determining the fate of a tumor cell in response to TMZ and other DNA methylators.展开更多
DNA is highly vulnerable to spontaneous and environmental timely damage in living cells.DNA damage may cause genetic instability and increase cancer risk if the damages are not repaired timely and efficiently.Human ce...DNA is highly vulnerable to spontaneous and environmental timely damage in living cells.DNA damage may cause genetic instability and increase cancer risk if the damages are not repaired timely and efficiently.Human cells possess several DNA damage response(DDR)mechanisms to protect the integrity of their genome.Clarification of the mechanisms under-lying the DNA damage response following lethal damage will facilitate the identification of therapeutic targets for cancers.Histone post-translational modifications(PTMs)have been indicated to play different roles in the repair of DNA damage.In this context,histone PTMs regulate recruitment of downstream effectors,and facilitate appropriate repair response.This review outlines the current understanding of different histone PTMs in response to DNA dam-age repair,besides,enumerates the role of new type PTMs such as histone succinylation and crotonylation in regulating DNA damage repair processes.展开更多
基金Acknowledgments Research in author＇s lab was supported in part by a grant from the National Natural Science Foundation of China （No. 30671065）, the Research Fund for the Doctoral Program of High Education （No. 20060027008）, and the National Important Basic Research Project （No. 2007CB507402） to Yusheng Cong. Support from NASA grants NNJ06HD92G and NNJ05HD36G （JWS） is acknowledged.
文摘Telomerase has fundamental roles in bypassing cellular aging and in cancer progression by maintaining telomere homeostasis and integrity. However, recent studies have led some investigators to suggest novel biochemical properties of telomerase in several essential cell signaling pathways without apparent involvement of its well established function in telomere maintenance. These observations may further enhance our understanding of the molecular actions of telomerase in aging and cancer. This review will provide an update on the extracurricular activities of telomerase in apoptosis, DNA repair, stern cell function, and in the regulation of gene expression.
基金the Canadian Institutes of Health Research and the Cancer Research Society, and fellowships by the Health Research Funds of Quebec, Canada
文摘Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase activities. Cellular senescence is a safeguard program limiting the proliferative competence of cells in living organisms. Apoptosis eliminates unwanted cells by the coordinated activity of gene products that regulate and effect cell death. The intimate link between the cell cycle, cellular senes- cence, apoptosis regulation, cancer development and tumor responses to cancer treatment has become eminently apparent. Extensive research on tumor suppressor genes, oncogenes, the cell cycle and apoptosis regulatory genes has revealed how the DNA damage-sensing and -signaling pathways, referred to as the DNA-damage response network, are tied to cell proliferation, cell-cycle arrest, cellular senescence and apoptosis. DNA-damage responses are complex, involving “sensor” proteins that sense the damage, and transmit signals to “transducer” proteins, which, in turn, convey the signals to numerous “effector” proteins implicated in specific cellular pathways, including DNA repair mechanisms, cell-cycle checkpoints, cellular senescence and apoptosis. The Bcl-2 family of proteins stands among the most crucial regulators of apoptosis and performs vital functions in deciding whether a cell will live or die after cancer chemotherapy and irradiation. In addition, several studies have now revealed that members of the Bcl-2 family also interface with the cell cycle, DNA repair/recombination and cellular senescence, effects that are generally distinct from their function in apoptosis. In this review, we report progress in understanding the molecular networks that regulate cell-cycle checkpoints, cellular senescence and apoptosis after DNA damage, and discuss the influence of some Bcl-2 family members on cell-cycle checkpoint regulation.
基金supported in part by a grant from National Natural Science Foundation of China(81802255)Shanghai Pujiang Program(17PJD036,China)+6 种基金a grant from Shanghai Municipal Commission of Health and Family Planning Program(20174Y0131,China)National Key Research&Development Project(2016YFC0902300,China)major disease clinical skills enhancement program of three year action plan for promoting clinical skills and clinical innovation in municipal hospitalsShanghai Shen Kang Hospital Development Center Clinical Research Plan of SHDC(16CR1001A,China)“Dream Tutor”Outstanding Young Talents Program(fkyq1901,China)key disciplines of Shanghai Pulmonary Hospital(2017ZZ02012,China)grant of Shanghai Science and Technology Commission(16JC1405900,China)。
文摘Genomic instability remains an enabling feature of cancer and promotes malignant transformation.Alterations of DNA damage response(DDR)pathways allow genomic instability,generate neoantigens,upregulate the expression of programmed death ligand 1(PD-L1)and interact with signaling such as cyclic GMPe AMP synthase-stimulator of interferon genes(cGASe STING)signaling.Here,we review the basic knowledge of DDR pathways,mechanisms of genomic instability induced by DDR alterations,impacts of DDR alterations on immune system,and the potential applications of DDR alterations as biomarkers and therapeutic targets in cancer immunotherapy.
文摘The genomes of eukaryotic cells are under continuous assault by environmental agents and endogenous metabolic byproducts. Damage induced in DNA usually leads to a cascade of cellular events, the DNA damage response. Failure of the DNA damage response can lead to development of malignancy by reducing the efficiency and fidelity of DNA repair. The NBS1 protein is a component of the MRE11/RAD50/NBS 1 complex （MRN） that plays a critical role in the cellular response to DNA damage and the maintenance of chromosomal integrity. Mutations in the NBS1 gene are responsible for Nijmegen breakage syndrome （NBS）, a hereditary disorder that imparts an increased predisposition to development of malignancy. The phenotypic characteristics of cells isolated from NBS patients point to a deficiency in the repair of DNA double strand breaks. Here, we review the current knowledge of the role of NBS1 in the DNA damage response. Emphasis is placed on the role of NBS1 in the DNA double strand repair, modulation of the DNA damage sensing and signaling, cell cycle checkpoint control and maintenance oftelomere stability.
基金This work was supported in part by grants from the National Institutes of Health(CA132755 to XY)the Developmental fund from the University of Michigan Cancer Center.
文摘BRCA1 is a well-established tumor suppressor gene,which is frequently mutated in familial breast and ovarian cancers.The gene product of BRCA1 functions in a number of cellular pathways that maintain genomic stability,including DNA damage-induced cell cycle checkpoint activation,DNA damage repair,protein ubiquitination,chromatin remodeling,as well as transcriptional regulation and apoptosis.In this review,we discuss recent advances regarding our understanding of the role of BRCA1 in tumor suppression and DNA damage response,including DNA damage-induced cell cycle checkpoint activation and DNA damage repair.
文摘Natural killer （NK） cells are a major component of the host innate immune defense against various pathogens. Several viruses, including hepatitis C virus （HCV）, have developed strategies to evade the NK-cell response. In our study, we found HCV infection could trigger DNA damage response by both ataxia telangiectasia mutated （ATM） and ATM- and Rad3-related （ATR） pathways. Recent reports had revealed that NKG2D ligands （NK cell- activating ligands） were upregulated when a major DNA damage checkpoint pathway was activated. However, here we found that DNA damage response was activated but NKG2D ligands were downregulated upon HCV infection. Further studies showed that the protease NS3/4A of HCV which had been shown relation with immune invasion contributed to the reduced expression of NKG2D ligands. These findings provide a novel insight into the mechanisms evolved by HCV to escape from the NK cell response. Cellular ＆ Molecular Immunology. 2008;5（6）： 475-478.
基金National Natural Science Foundation of China, No. 30772605, 30700413
文摘AIM： To investigate whether hepatitis B virus （HBV） infection activates DNA damage response and DNA repair cofactors inhibit HBV infection and replication. METHODS： Human hepatocyte cell line HL7702 was studied. Immunoblotting was performed to test the expression of ataxia telangiectasia-mutated （ATM）- Rad3-related protein （ATR）, p21 and the level of phosphorylation of Chkl, p53, H2AX, ATM in HBV-infected or non-infected-cells. Special short RNAi oligos was transfected to induce transient ATR knockdown in HL7702. ATR-ATN chemical inhibitors caffeine （CF） and theophylline （TP）, or Chkl inhibitor 7-hydroxystaurosporine （UCN01） was studied to determine whether they suppress cellular DNA damage response and NG132 inhibits proteasome. RESULTS： The ATR checkpoint pathway, responding to single-strand breaks in DNA, was activated in response to HBV infection. ATR knockdown cells decreased the HBV DNA yields, implying that HBV infection and replication could activate and exploit the activated DNA damage response. CF/TP or UCN01 reduced the HBV DNA yield by 70% and 80%, respectively. HBV abrogated the ATR-dependent DNA damage signaling pathway by degrading p21, and introduction of the p21 protein before HBV infection reduced the HBV DNA yield. Consistent with this result, p21 accumulation after NG132 treatment also sharply decreased the HBV DNA yield. CONCLUSION： HBV infection can be treated with therapeutic approaches targeting host cell proteins by inhibiting a cellular gene required for HBV replication or by restoring a response abrogated by HBV, thus providing a potential approach to the prevention and treatment of HBV infection.
基金financed by Sāo Paulo Research Foundation(FAPESP,grant number 2015/21464-0)Coordination for the Improvement of Higher Education Personnel(CAPES,grant number 1460154)the National Council for Scientific and Technological Development(CNPq,grant number 310120/2015-2).
文摘Gastric cancer remains one of the leading causes of cancer-related death worldwide,and most of the cases are associated with Helicobacter pylori infection.This bacterium promotes the production of reactive oxygen species(ROS),which cause DNA damage in gastric epithelial cells.In this study,we evaluated the expression of important genes involved in the recognition of DNA damage(ATM,ATR,and H2AX)and ROS-induced damage repair(APE1)and the expression of some miRNAs(miR-15a,miR-21,miR-24,miR-421 and miR-605)that target genes involved in the DNA damage response(DDR)in 31 fresh tissues of gastric cancer.Cytoscape v3.1.1 was used to construct the postulated miRNA:mRNA interaction network.Analysis performed by real-time quantitative PCR exhibited significantly increased levels of the APE1(RQ=2.55,p<0.0001)and H2AX(RQ=2.88,p=0.0002)genes beyond the miR-421 and miR-605 in the gastric cancer samples.In addition,significantly elevated levels of miR-21,miR-24 and miR-421 were observed in diffuse-type gastric cancer.Correlation analysis reinforced some of the gene:gene(ATM/ATR/H2AX)and miRNA:mRNA relationships obtained also with the interaction network.Thus,our findings show that tumor cells from gastric cancer presents deregulation of genes and miRNAs that participate in the recognition and repair of DNA damage,which could confer an advantage to cell survival and proliferation in the tumor microenvironment.
基金supported by National Natural Science Foundation of China(No.81930090,82203974)Natural Science Foundation of Chongqing City,China(No.CSTB2023NSCQ-MSX0284)+2 种基金Postdoctoral Innovative Talent Support Program of China(No.BX20220398)China Postdoctoral Science Foundation(No.2022M723867)Postdoctoral Innovative Talent Support Program of Chongqing,(No.CQBX2021017)China.
文摘The hematopoietic system is susceptible to ionizing radiation(IR),which can cause acute hematopoietic failure or long-term myelosuppression.As the most primitive cells of the hematopoietic hierarchy,hematopoietic stem cells(HSCs)maintain lifelong hematopoietic homeostasis and promote hematopoietic regeneration during stress.Numerous studies have shown that nuclear and mitochondrial genomes are the main targets of radiation injury in HSCs.More importantly,the damage of DNA may trigger a series of biological responses that largely determine HSC fate following IR exposure.Although some essential pathways and factors involved in DNA injury and damage in HSCs have been revealed,a comprehensive understanding of the biological effects of radiation on HSCs still needs to be improved.This review focuses on recent insights into the molecular mechanisms underlying DNA damage and repair in HSCs after IR.Then summarize corresponding regulatory measures,which may provide a reference for further research in this field.
基金supported by NIH grants 5-P50-NS20023 and NS030245 (Darell D. Bigner)a grant from the Pediatric Brain Tumor Foundation (Henry S. Friedman)
文摘Glioblastoma multiforme （GBM） is the most aggressive primary brain tumor in adults.Current therapy includes surgery,radiation and chemotherapy with temozolomide （TMZ）.Major determinants of clinical response to TMZ include methylation status of the O6-methylguanine-DNA methyltransferase （MGMT） promoter and mismatch repair （MMR） status.Though the MGMT promoter is methylated in 45% of cases,for the first nine months of follow-up,TMZ does not change survival outcome.Furthermore,MMR deficiency makes little contribution to clinical resistance,suggesting that there exist unrecognized mechanisms of resistance.We generated paired GBM cell lines whose resistance was attributed to neither MGMT nor MMR.We show that,responding to TMZ,these cells exhibit a decoupling of DNA damage response （DDR） from ongoing DNA damages.They display methylation-resistant synthesis in which ongoing DNA synthesis is not inhibited.They are also defective in the activation of the S and G2 phase checkpoint.DDR proteins ATM,Chk2,MDC1,NBS1 and gammaH2AX also fail to form discrete foci.These results demonstrate that failure of DDR may play an active role in chemoresistance to TMZ.DNA damages by TMZ are repaired by MMR proteins in a futile,reiterative process,which activates DDR signaling network that ultimately leads to the onset of cell death.GBM cells may survive genetic insults in the absence of DDR.We anticipate that our findings will lead to more studies that seek to further define the role of DDR in ultimately determining the fate of a tumor cell in response to TMZ and other DNA methylators.
基金supported by National Natural Science Foundation of China(No.82071695,82060535)Natural Science Foundation of Gansu Province,China(No.21JR7RA450)。
文摘DNA is highly vulnerable to spontaneous and environmental timely damage in living cells.DNA damage may cause genetic instability and increase cancer risk if the damages are not repaired timely and efficiently.Human cells possess several DNA damage response(DDR)mechanisms to protect the integrity of their genome.Clarification of the mechanisms under-lying the DNA damage response following lethal damage will facilitate the identification of therapeutic targets for cancers.Histone post-translational modifications(PTMs)have been indicated to play different roles in the repair of DNA damage.In this context,histone PTMs regulate recruitment of downstream effectors,and facilitate appropriate repair response.This review outlines the current understanding of different histone PTMs in response to DNA dam-age repair,besides,enumerates the role of new type PTMs such as histone succinylation and crotonylation in regulating DNA damage repair processes.
