The molecular mechanism of DNA damage induced by hydroquinone (HQ) remains unclear. Poly(ADP-ribose) polymerase-1 (PARP-1) usually works as a DNA damage sensor, and hence, it is possible that PARP-1 is involved ...The molecular mechanism of DNA damage induced by hydroquinone (HQ) remains unclear. Poly(ADP-ribose) polymerase-1 (PARP-1) usually works as a DNA damage sensor, and hence, it is possible that PARP-1 is involved in the DNA damage response induced by HQ. In TK6 cells treated with HQ, PARP activity as well as the expression of apoptosis antagonizing transcription factor (AATF), PARP-1, and phosphorylated H2AX (v-H2AX) were maximum at 0.5 h, 6 h, 3 h, and 3 h, respectively. To explore the detailed mechanisms underlying the prompt DNA repair reaction, the above indicators were investigated in PARP-l-silenced cells. PARP activity and expression of AATF and PARP-1 decreased to 36%, 32%, and 33%, respectively, in the cells; however, y-H2AX expression increased to 265%. Co-immunoprecipitation (co-IP) assays were employed to determine whether PARP-1 and AATF formed protein complexes. The interaction between these proteins together with the results from IP assays and confocal microscopy indicated that poly(ADP-ribosyl)ation {PARylation) regulated AATF expression, in conclusion, PARP-1 was involved in the DNA damage repair induced by HQ via increasing the accumulation of AATF through PARylation.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
Objective:RECQL4(a member of the RECQ helicase family)upregulation has been reported to be associated with tumor progression in several malignancies.However,whether RECQL4 sustains esophageal squamous cell carcinoma(E...Objective:RECQL4(a member of the RECQ helicase family)upregulation has been reported to be associated with tumor progression in several malignancies.However,whether RECQL4 sustains esophageal squamous cell carcinoma(ESCC)has not been elucidated.In this study,we determined the functional role for RECQL4 in ESCC progression.Methods:RECQL4 expression in clinical samples of ESCC was examined by immunohistochemistry.Cell proliferation,cellular senescence,the epithelial-mesenchymal transition(EMT),DNA damage,and reactive oxygen species in ESCC cell lines with RECQL4 depletion or overexpression were analyzed.The levels of proteins involved in the DNA damage response(DDR),cell cycle progression,survival,and the EMT were determined by Western blot analyses.Results:RECQL4 was highly expressed in tumor tissues when compared to adjacent non-tumor tissues in ESCC(P<0.001)and positively correlated with poor differentiation(P=0.011),enhanced invasion(P=0.033),and metastasis(P=0.048).RECQL4 was positively associated with proliferation and migration in ESCC cells.Depletion of RECQL4 also inhibited growth of tumor xenografts in vivo.RECQL4 depletion induced G0/G1 phase arrest and cellular senescence.Importantly,the levels of DNA damage and reactive oxygen species were increased when RECQL4 was depleted.DDR,as measured by the activation of ATM,ATR,CHK1,and CHK2,was impaired.RECQL4 was also shown to promote the activation of AKT,ERK,and NF-k B in ESCC cells.Conclusions:The results indicated that RECQL4 was highly expressed in ESCC and played critical roles in the regulation of DDR,redox homeostasis,and cell survival.展开更多
DNA damage response (DDR) in different cell cycle status of human peripheral blood lymphocytes (PBLs) and the role of H2AX in DDR were investigated. The PBLs were stimulated into cell cycle with phytohemagglutinin...DNA damage response (DDR) in different cell cycle status of human peripheral blood lymphocytes (PBLs) and the role of H2AX in DDR were investigated. The PBLs were stimulated into cell cycle with phytohemagglutinin (PHA). The apoptotic ratio and the phosphorylation H2AX (S139) were flow cytometrically measured in resting and proliferating PBLs after treatment with camptothecin (CPT) or X-ray. The expressions of γH2AX, Bcl-2, caspase-3 and caspase-9 were detected by Western blotting. DDR in 293T cells was detected after H2AX was silenced by RNAi method. Our results showed that DNA double strand breaks (DSBs) were both induced in quiescent and proliferating PBLs after CPT or X-ray treatment. The phosphorylation of H2AX and apoptosis were more sensitive in proliferating PBLs compared with quiescent lymphocytes (P0.05). The expression levels of anti-apoptotic proteins Bcl-2 were reduced and cleaved caspase-3 and caspase-9 were increased. No significant changes were observed in CPT-induced apoptosis in 293T cells between H2AX knocking down group and controls. It was concluded that proliferating PBLs were more vulnerable to DNA damage compared to non-stimulated lymphocytes and had higher apoptosis rates. γH2AX may only serve as a marker of DNA damage but exert no effect on apoptosis regulation.展开更多
Objective:DNA damage response(DDR)genes have low mutation rates,which may restrict their clinical applications in predicting the outcomes of immune checkpoint inhibitor(ICI)treatment.Thus,a systemic analysis of multip...Objective:DNA damage response(DDR)genes have low mutation rates,which may restrict their clinical applications in predicting the outcomes of immune checkpoint inhibitor(ICI)treatment.Thus,a systemic analysis of multiple DDR genes is needed to identify potential biomarkers of ICI efficacy.Methods:A total of 39,631 patients with mutation data were selected from the cBioPortal database.A total of 155 patients with mutation data were obtained from the Fudan University Shanghai Cancer Center(FUSCC).A total of 1,660 patients from the MSK-IMPACT cohort who underwent ICI treatment were selected for survival analysis.A total of 249 patients who underwent ICI treatment from the Dana-Farber Cancer Institute(DFCI)cohort were obtained from a published dataset.The Cancer Genome Atlas(TCGA)level 3 RNA-Seq version 2 RSEM data for gastric cancer were downloaded from cBioPortal.Results:Six MMR and 30 DDR genes were included in this study.Six MMR and 20 DDR gene mutations were found to predict the therapeutic efficacy of ICI,and most of them predicted the therapeutic efficacy of ICI,in a manner dependent on TMB,except for 4 combined DDR gene mutations,which were associated with the therapeutic efficacy of ICI independently of the TMB.Single MMR/DDR genes showed low mutation rates;however,the mutation rate of all the MMR/DDR genes associated with the therapeutic efficacy of ICI was relatively high,reaching 10%–30%in several cancer types.Conclusions:Coanalysis of multiple MMR/DDR mutations aids in selecting patients who are potential candidates for immunotherapy.展开更多
Objective:Mitotic arrest-deficient protein 1(MAD1)is a kinetochore protein essential for the mitotic spindle checkpoint.Proteomic studies have indicated that MAD1 is a component of the DNA damage response(DDR)pathway....Objective:Mitotic arrest-deficient protein 1(MAD1)is a kinetochore protein essential for the mitotic spindle checkpoint.Proteomic studies have indicated that MAD1 is a component of the DNA damage response(DDR)pathway.However,whether and how MAD1 might be directly involved in the DDR is largely unknown.Methods:We ectopically expressed the wild type,or a phosphorylation-site--mutated form of MAD1 in MAD1 knockdown cells to look for complementation effects.We used the comet assay,colony formation assay,immunofluorescence staining,and flow cytometry to assess the DDR,radiosensitivity,and the G2/M checkpoint.We employed co-immunoprecipitation followed by mass spectrometry to identify MAD1 interacting proteins.Data were analyzed using the unpaired Student'st-test.Results:We showed that MAD1 was required for an optimal DDR,as knocking down MAD1 resulted in impaired DNA repair and hypersensitivity to ionizing radiation(IR).We found that IR-induced serine 214 phosphorylation was ataxia-telangiectasia mutated(ATM)kinase-dependent.Mutation of serine 214 to alanine failed to rescue the phenotypes of MAD1 knockdown cells in response to IR.Using mass spectrometry,we identified a protein complex mediated by MAD1 serine 214 phosphorylation in response to IR.Among them,we showed that KU80 was a key protein that displayed enhanced interaction with MAD1 after DNA damage.Finally,we showed that MAD1 interaction with KU80 required serine 214 phosphorylation,and it was essential for activation of DNA protein kinases catalytic subunit(DNA-PKcs).Conclusions:MAD1 serine 214 phosphorylation mediated by ATM kinase in response to IR was required for the interaction with KU80 and activation of DNA-PKCs.展开更多
The activation of some oncogenes promote cancer cell proliferation and growth,facilitate cancer progression and metastasis by induce DNA replication stress,even genome instability.Activation of the cyclic GMP-AMP synt...The activation of some oncogenes promote cancer cell proliferation and growth,facilitate cancer progression and metastasis by induce DNA replication stress,even genome instability.Activation of the cyclic GMP-AMP synthase(cGAS)mediates classical DNA sensing,is involved in genome instability,and is linked to various tumor development or therapy.However,the function of cGAS in gastric cancer remains elusive.In this study,the TCGA database and retrospective immunohistochemical analyses revealed substantially high cGAS expression in gastric cancer tissues and cell lines.By employing cGAS high-expression gastric cancer cell lines,including AGS and MKN45,ectopic silencing of cGAS caused a significant reduction in the proliferation of the cells,tumor growth,and mass in xenograft mice.Mechanistically,database analysis predicted a possible involvement of cGAS in the DNA damage response(DDR),further data through cells revealed protein interactions of the cGAS and MRE11-RAD50-NBN(MRN)complex,which activated cell cycle checkpoints,even increased genome instability in gastric cancer cells,thereby contributing to gastric cancer progression and sensitivity to treatment with DNA damaging agents.Furthermore,the upregulation of cGAS significantly exacerbated the prognosis of gastric cancer patients while improving radiotherapeutic outcomes.Therefore,we concluded that cGAS is involved in gastric cancer progression by fueling genome instability,implying that intervening in the cGAS pathway could be a practicable therapeutic approach for gastric cancer.展开更多
Objective Abnormal expression of T-lymphokine-activated killer cell-originated protein kinase(TOPK)was reported to be closely related to the resistance of prostate cancer to radiotherapy and to targeted drug resistanc...Objective Abnormal expression of T-lymphokine-activated killer cell-originated protein kinase(TOPK)was reported to be closely related to the resistance of prostate cancer to radiotherapy and to targeted drug resistance in lung cancer.However,the role of TOPK inhibition in enhancing radiosensitivity of colorectal cancer(CRC)cells is unclear.This study aimed to evaluate the radiosensitization of TOPK knockdown in CRC cells.Methods The expression of TOPK was detected in CRC tissues by immunohistochemistry,and the effect of TOPK knockdown was detected in CRC cells by Western blotting.CCK-8 and clonogenic assays were used to detect the growth and clonogenic ability of CRC cells after TOPK knockdown combined with radiotherapy in CRC cells.Furthermore,proteomic analysis showed that the phosphorylation of TOPK downstream proteins changed after radiotherapy.DNA damage was detected by the comet assay.Changes in the DNA damage response signaling pathway were analyzed by Western blotting,and apoptosis was detected by flow cytometry.Results The expression of TOPK was significantly greater in CRC tissues at grades 2–4 than in those at grade 1.After irradiation,CRC cells with genetically silenced TOPK had shorter comet tails and reduced expression levels of DNA damage response-associated proteins,including phospho-cyclin-dependent kinase 1(p-CDK1),phospho-ataxia telangiectasia-mutated(p-ATM),poly ADP-ribose polymerase(PARP),and meiotic recombination 11 homolog 1(MRE11).Conclusions TOPK was overexpressed in patients with moderately to poorly differentiated CRC.Moreover,TOPK knockdown significantly enhanced the radiosensitivity of CRC cells by reducing the DNA damage response.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
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
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
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 DNA damage response(DDR)is a signal transduction pathway that decides the cell’s fate either to repair DNA damage or to undergo apoptosis if there is too much damage.Post-translational modifications modulate the ...The DNA damage response(DDR)is a signal transduction pathway that decides the cell’s fate either to repair DNA damage or to undergo apoptosis if there is too much damage.Post-translational modifications modulate the assembly and activity of protein complexes during the DDR pathways.MicroRNAs(miRNAs)are emerging as a class of endogenous gene modulators that control protein levels,thereby adding a new layer of regulation to the DDR.In this review,we describe a new role for miRNAs in regulating the cellular response to DNA damage with a focus on DNA double-strand break damage.We also discuss the implications of miRNA’s role in the DDR to stem cells,including embryonic stem cells and cancer stem cells,stressing the potential applications for miRNAs to be used as sensitizers for cancer radiotherapy and chemotherapy.展开更多
O-GlcNAcylation is an important post-translational modification and has been implicated in many fundamental cellular processes. Recent studies showed that O-linked N-acetylglucosamine (GlcNAc) transferase (OGT) me...O-GlcNAcylation is an important post-translational modification and has been implicated in many fundamental cellular processes. Recent studies showed that O-linked N-acetylglucosamine (GlcNAc) transferase (OGT) mediated O-GlcNAcylation of histone H2B Ser 112 (H2B S 112 GlcNAcylation) plays an important role in gene transcription. However, the role of this histone modification in DNA damage response has not been studied yet. In this study, we found that OGT and OGT mediated H2B S112 GlcNAcylation are involved in DNA damage response for maintaining genomic stability and are required for resistance to many DNA-damaging and replication stress- inducing agents. OGT mediated H2B Sl12 GlcNAcylation increased locally upon the induction of double-strand breaks (DSBs), and depletion of OGT or overexpression of H2B S 112A mutant impaired homologous recombination (HR) and nonhomologous end-joining (NHEJ). Mechanistically, H2B Sl12 GlcNAcylation could bind Nijmegen breakage syndrome 1 (NBS1) and regulate NBS1 foci for- mation. Taken together, our results demonstrate a new function of histone O-GlcNAcylation in DNA damage response (DDR).展开更多
Background:Desmoplastic small round cell tumor(DSRCT)is a rare,aggressive,and poorly investigated simple sarcoma with a low frequency of genetic deregulation other than an Ewing sarcoma RNA binding protein 1(EWSR1)-W...Background:Desmoplastic small round cell tumor(DSRCT)is a rare,aggressive,and poorly investigated simple sarcoma with a low frequency of genetic deregulation other than an Ewing sarcoma RNA binding protein 1(EWSR1)-Wilm’s tumor suppressor(WT1)translocation.We used whole-exome sequencing to interrogate six consecutive pretreated DSRCTs whose gene expression was previously investigated.Methods:DNA libraries were prepared from formalin-fixed,paraffin-embedded archival tissue specimens following the Agilent SureSelectXT2 target enrichment protocol and sequenced on Illumina NextSeq 500.Raw sequence data were aligned to the reference genome with Burrows-Wheeler Aligner algorithm.Somatic mutations and copy number alterations(CNAs)were identified using MuTect2 and EXCAVATOR2,respectively.Biological functions associated with altered genes were investigated through Ingenuity Pathway Analysis(IPA)software.Results:A total of 137 unique somatic mutations were identified:133 mutated genes were case-specific,and 2 were mutated in two cases but in different positions.Among the 135 mutated genes,27%were related to two biological categories:DNA damage-response(DDR)network that was also identified through IPA and mesenchymal-epithelial reverse transition(MErT)/epithelial-mesenchymal transition(EMT)already demonstrated to be relevant in DSRCT.The mutated genes in the DDR network were involved in various steps of transcription and particularly affected pre-mRNA.Half of these genes encoded RNA-binding proteins or DNA/RNA-binding proteins,which were recently rec-ognized as a new class of DDR players.CNAs in genes/gene families,involved in MErT/EMT and DDR,were recurrent across patients and mostly segregated in the MErT/EMT category.In addition,recurrent gains of regions in chromosome 1 involving many MErT/EMT gene families and loss of one arm or the entire chromosome 6 affecting relevant immune-regulatory genes were recorded.Conclusions:The emerging picture is an extreme inter-tumor heterogeneity,characterized by the concurrent deregulation of the DDR and MErT/EMT dynamic and plastic programs that could favour genomic instability and explain the refractory DSRCT profile.展开更多
DNA damage response(DDR) is essential for maintaining genome stability and protecting cells from tumorigenesis. Ubiquitin and ubiquitin-like modi?cations play an important role in DDR, from signaling DNA damage to med...DNA damage response(DDR) is essential for maintaining genome stability and protecting cells from tumorigenesis. Ubiquitin and ubiquitin-like modi?cations play an important role in DDR, from signaling DNA damage to mediating DNA repair. In this report, we found that the E3 ligase ring ?nger protein 126(RNF126) was recruited to UV laser micro-irradiation-induced stripes in a RNF8-dependent manner. RNF126 directly interacted with and ubiquitinated another E3 ligase, RNF168. Overexpression of wild type RNF126, but not catalytically-inactive mutant RNF126(CC229/232 AA), diminished ubiquitination of H2 A histone family member X(H2AX),and subsequent bleomycin-induced focus formation of total ubiquitin FK2, TP53-binding protein1(53 BP1), and receptor-associated protein 80(RAP80). Interestingly, both RNF126 overexpression and RNF126 downregulation compromised homologous recombination(HR)-mediated repair of DNA double-strand breaks(DSBs). Taken together, our ?ndings demonstrate that RNF126 negatively regulates RNF168 function in DDR and its appropriate cellular expression levels are essential for HR-mediated DSB repair.展开更多
Decabrominated diphenyl ether(BDE-209)is generally utilized in multiple polymer materials as common brominated flame retardant.BDE-209 has been listed as persistent organic pollutants(POPs),which was considered to be ...Decabrominated diphenyl ether(BDE-209)is generally utilized in multiple polymer materials as common brominated flame retardant.BDE-209 has been listed as persistent organic pollutants(POPs),which was considered to be reproductive toxin in the environment.But it still remains unclear about the effects of BDE-209 on DNA methylation and the inducedmale reproductive toxicity.Due to the extensive epigenetic regulation in germ line development,we hypothesize that BDE-209 exposure impacts the statue of DNA methylation in spermatocytes in vitro.Therefore,the mouse GC-2spd(GC-2)cells were used for the genome wide DNA methylation analysis after treated with 32μg/mL BDE-209 for 24 hr.The results showed that BDE-209 caused genomic methylation changes with 32,083 differentially methylated CpGs in GC-2 cells,including 16,164(50.38%)hypermethylated and 15,919(49.62%)hypomethylated sites.With integrated analysis ofDNAmethylation data and functional enrichment,we found that BDE-209 might affect the functional transcription in cell growth and sperm development by differential gene methylation.qRT-PCR validation demonstrated the involvement of p53-dependent DNA damage response in the GC-2 cells after BDE-209 exposure.In general,our findings indicated that BDE-209-induced genome wide methylation changes could be interrelated with reproductive dysfunction.This study might provide new insights into the mechanisms of male reproductive toxicity under the environmental exposure to BDE-209.展开更多
Maintenance of tissue-specific stem cells is vital for organ homeostasis and organismal longevity.Hematopoietic stem cells(HSCs) are the most primitive cell type in the hematopoietic system.They divide asymmetricall...Maintenance of tissue-specific stem cells is vital for organ homeostasis and organismal longevity.Hematopoietic stem cells(HSCs) are the most primitive cell type in the hematopoietic system.They divide asymmetrically and give rise to daughter cells with HSC identity(selfrenewal) and progenitor progenies(differentiation),which further proliferate and differentiate into full hematopoietic lineages.Mammalian ageing process is accompanied with abnormalities in the HSC self-renewal and differentiation.Transcriptional changes and epigenetic modulations have been implicated as the key regulators in HSC ageing process.The DNA damage response(DDR)in the cells involves an orchestrated signaling pathway,consisting of cell cycle regulation,cell death and senescence,transcriptional regulation,as well as chromatin remodeling.Recent studies employing DNA repair-deficient mouse models indicate that DDR could intrinsically and extrinsically regulate HSC maintenance and play important roles in tissue homeostasis of the hematopoietic system.In this review,we summarize the current understanding of how the DDR determines the HSC fates and finally contributes to organismal ageing.展开更多
Resistance of cancer patients to DNA damaging radiation therapy and chemotherapy remains a major problem in the clinic.The current review discusses the molecular mechanisms of therapy resistance in acute myeloid leuke...Resistance of cancer patients to DNA damaging radiation therapy and chemotherapy remains a major problem in the clinic.The current review discusses the molecular mechanisms of therapy resistance in acute myeloid leukemia(AML)conferred by cooperative chemotherapy-induced DNA damage response(DDR)and mutational activation of PI3K/AKT signaling.In addition,strategies to overcome resistance are discussed,with particular focus on studies underpinning the vast potential of therapies combining standard chemotherapy AML regimens with small molecule inhibitors targeting key regulatory hubs at the interface of DDR and oncogenic signaling pathways.展开更多
DNA damage response(DDR)is a highly conserved genome surveillance mechanism that preserves cell viability in the presence of chemotherapeutic drugs.Hence,small molecules that inhibit DDR are expected to enhance the an...DNA damage response(DDR)is a highly conserved genome surveillance mechanism that preserves cell viability in the presence of chemotherapeutic drugs.Hence,small molecules that inhibit DDR are expected to enhance the anti-cancer effect of chemotherapy.Through a recent chemical library screen,we identified shikonin as an inhibitor that strongly suppressed DDR activated by various chemotherapeutic drugs in cancer cell lines derived from different origins.Mechanistically,shikonin inhibited the activation of ataxia telangiectasia mutated(ATM),and to a lesser degree ATM and RAD3-related(ATR),two master upstream regulators of the DDR signal,through inducing degradation of ATM and ATR-interacting protein(ATRIP),an obligate associating protein of ATR,respectively.As a result of DDR inhibition,shikonin enhanced the anti-cancer effect of chemotherapeutic drugs in both cell cultures and in mouse models.While degradation of ATRIP is proteasome dependent,that of ATM depends on caspase-and lysosome-,but not proteasome.Overexpression of ATM significantly mitigated DDR inhibition and cell death induced by shikonin and chemotherapeutic drugs.These novel findings reveal shikonin as a pan DDR inhibitor and identify ATM as a primary factor in determining the chemo sensitizing effect of shikonin.Our data may facilitate the development of shikonin and its derivatives as potential chemotherapy sensitizers through inducing ATM degradation.展开更多
基金supported by grants from the National Natural Science Foundation of China(8120223181273116+2 种基金81430079)the Science and Technology Program of Guangdong Bureau of Science and TechnologyChina(2013B021800069)
文摘The molecular mechanism of DNA damage induced by hydroquinone (HQ) remains unclear. Poly(ADP-ribose) polymerase-1 (PARP-1) usually works as a DNA damage sensor, and hence, it is possible that PARP-1 is involved in the DNA damage response induced by HQ. In TK6 cells treated with HQ, PARP activity as well as the expression of apoptosis antagonizing transcription factor (AATF), PARP-1, and phosphorylated H2AX (v-H2AX) were maximum at 0.5 h, 6 h, 3 h, and 3 h, respectively. To explore the detailed mechanisms underlying the prompt DNA repair reaction, the above indicators were investigated in PARP-l-silenced cells. PARP activity and expression of AATF and PARP-1 decreased to 36%, 32%, and 33%, respectively, in the cells; however, y-H2AX expression increased to 265%. Co-immunoprecipitation (co-IP) assays were employed to determine whether PARP-1 and AATF formed protein complexes. The interaction between these proteins together with the results from IP assays and confocal microscopy indicated that poly(ADP-ribosyl)ation {PARylation) regulated AATF expression, in conclusion, PARP-1 was involved in the DNA damage repair induced by HQ via increasing the accumulation of AATF through PARylation.
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(Grant Nos.81572785,31771260,and 81201750)a Ministry of Science and Technology(Grant No.2011CB966200)+2 种基金the Excellent Young and Mid-Career Scientist Award of Shandong Province(Grant No.BS2013YY023)the Key Research Project of Shandong Province(Grant No.2016GSF201072)the Project of State Key Laboratory of Radiation Medicine and Protection,Soochow University(Grant No.GZN1201804)。
文摘Objective:RECQL4(a member of the RECQ helicase family)upregulation has been reported to be associated with tumor progression in several malignancies.However,whether RECQL4 sustains esophageal squamous cell carcinoma(ESCC)has not been elucidated.In this study,we determined the functional role for RECQL4 in ESCC progression.Methods:RECQL4 expression in clinical samples of ESCC was examined by immunohistochemistry.Cell proliferation,cellular senescence,the epithelial-mesenchymal transition(EMT),DNA damage,and reactive oxygen species in ESCC cell lines with RECQL4 depletion or overexpression were analyzed.The levels of proteins involved in the DNA damage response(DDR),cell cycle progression,survival,and the EMT were determined by Western blot analyses.Results:RECQL4 was highly expressed in tumor tissues when compared to adjacent non-tumor tissues in ESCC(P<0.001)and positively correlated with poor differentiation(P=0.011),enhanced invasion(P=0.033),and metastasis(P=0.048).RECQL4 was positively associated with proliferation and migration in ESCC cells.Depletion of RECQL4 also inhibited growth of tumor xenografts in vivo.RECQL4 depletion induced G0/G1 phase arrest and cellular senescence.Importantly,the levels of DNA damage and reactive oxygen species were increased when RECQL4 was depleted.DDR,as measured by the activation of ATM,ATR,CHK1,and CHK2,was impaired.RECQL4 was also shown to promote the activation of AKT,ERK,and NF-k B in ESCC cells.Conclusions:The results indicated that RECQL4 was highly expressed in ESCC and played critical roles in the regulation of DDR,redox homeostasis,and cell survival.
基金supported by grants from Program 973 from Ministry of ScienceTechnology of China (Nos. 2004CB518705, 2009CB5218702)the National Natural Sciences Foundation of China (Nos. 30872472, 30800569)
文摘DNA damage response (DDR) in different cell cycle status of human peripheral blood lymphocytes (PBLs) and the role of H2AX in DDR were investigated. The PBLs were stimulated into cell cycle with phytohemagglutinin (PHA). The apoptotic ratio and the phosphorylation H2AX (S139) were flow cytometrically measured in resting and proliferating PBLs after treatment with camptothecin (CPT) or X-ray. The expressions of γH2AX, Bcl-2, caspase-3 and caspase-9 were detected by Western blotting. DDR in 293T cells was detected after H2AX was silenced by RNAi method. Our results showed that DNA double strand breaks (DSBs) were both induced in quiescent and proliferating PBLs after CPT or X-ray treatment. The phosphorylation of H2AX and apoptosis were more sensitive in proliferating PBLs compared with quiescent lymphocytes (P0.05). The expression levels of anti-apoptotic proteins Bcl-2 were reduced and cleaved caspase-3 and caspase-9 were increased. No significant changes were observed in CPT-induced apoptosis in 293T cells between H2AX knocking down group and controls. It was concluded that proliferating PBLs were more vulnerable to DNA damage compared to non-stimulated lymphocytes and had higher apoptosis rates. γH2AX may only serve as a marker of DNA damage but exert no effect on apoptosis regulation.
基金This work was supported by the National Key R&D Program of China(Grant No.2018YFC1313300)the National Natural Science Foundation of China(Grant No.81572331).
文摘Objective:DNA damage response(DDR)genes have low mutation rates,which may restrict their clinical applications in predicting the outcomes of immune checkpoint inhibitor(ICI)treatment.Thus,a systemic analysis of multiple DDR genes is needed to identify potential biomarkers of ICI efficacy.Methods:A total of 39,631 patients with mutation data were selected from the cBioPortal database.A total of 155 patients with mutation data were obtained from the Fudan University Shanghai Cancer Center(FUSCC).A total of 1,660 patients from the MSK-IMPACT cohort who underwent ICI treatment were selected for survival analysis.A total of 249 patients who underwent ICI treatment from the Dana-Farber Cancer Institute(DFCI)cohort were obtained from a published dataset.The Cancer Genome Atlas(TCGA)level 3 RNA-Seq version 2 RSEM data for gastric cancer were downloaded from cBioPortal.Results:Six MMR and 30 DDR genes were included in this study.Six MMR and 20 DDR gene mutations were found to predict the therapeutic efficacy of ICI,and most of them predicted the therapeutic efficacy of ICI,in a manner dependent on TMB,except for 4 combined DDR gene mutations,which were associated with the therapeutic efficacy of ICI independently of the TMB.Single MMR/DDR genes showed low mutation rates;however,the mutation rate of all the MMR/DDR genes associated with the therapeutic efficacy of ICI was relatively high,reaching 10%–30%in several cancer types.Conclusions:Coanalysis of multiple MMR/DDR mutations aids in selecting patients who are potential candidates for immunotherapy.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.81672743 and 81974464)Beijing Tianjin Hebei Basic Research Cooperation Project(Grant No.19JCZDJC64500(Z))+4 种基金Shenzhen Basic Research Project(Grant No.JCYJ20160331114230843)Tianjin Municipal Health Commission(Grant Nos.2015KR11 and 2013KG134)Tianjin Municipal Science and Technology Bureau(Grant No.18JCYBJC27800)US NIH grant RO 1 CAI33093,the Alabama Innovation Fund of the United Statesthe Tianjin Medical University Cancer Institute and Hospital Innovation Fund(Grant No.1803)。
文摘Objective:Mitotic arrest-deficient protein 1(MAD1)is a kinetochore protein essential for the mitotic spindle checkpoint.Proteomic studies have indicated that MAD1 is a component of the DNA damage response(DDR)pathway.However,whether and how MAD1 might be directly involved in the DDR is largely unknown.Methods:We ectopically expressed the wild type,or a phosphorylation-site--mutated form of MAD1 in MAD1 knockdown cells to look for complementation effects.We used the comet assay,colony formation assay,immunofluorescence staining,and flow cytometry to assess the DDR,radiosensitivity,and the G2/M checkpoint.We employed co-immunoprecipitation followed by mass spectrometry to identify MAD1 interacting proteins.Data were analyzed using the unpaired Student'st-test.Results:We showed that MAD1 was required for an optimal DDR,as knocking down MAD1 resulted in impaired DNA repair and hypersensitivity to ionizing radiation(IR).We found that IR-induced serine 214 phosphorylation was ataxia-telangiectasia mutated(ATM)kinase-dependent.Mutation of serine 214 to alanine failed to rescue the phenotypes of MAD1 knockdown cells in response to IR.Using mass spectrometry,we identified a protein complex mediated by MAD1 serine 214 phosphorylation in response to IR.Among them,we showed that KU80 was a key protein that displayed enhanced interaction with MAD1 after DNA damage.Finally,we showed that MAD1 interaction with KU80 required serine 214 phosphorylation,and it was essential for activation of DNA protein kinases catalytic subunit(DNA-PKcs).Conclusions:MAD1 serine 214 phosphorylation mediated by ATM kinase in response to IR was required for the interaction with KU80 and activation of DNA-PKCs.
基金supported by Zhengzhou Major Collaborative Innovation Project(No.18XTZX12003)Key Projects of Discipline Construction in Zhengzhou University(No.XKZDJC202001)+2 种基金National Key Research and Development Program in China(No.2020YFC2006100)Excellent Foreign Scientist Studio of Henan Province in China(No.GZS2018001)Medical Service Capacity Improvement Project of Henan Province in China(Grant No.Yu Wei Medicine[2017]No.66).
文摘The activation of some oncogenes promote cancer cell proliferation and growth,facilitate cancer progression and metastasis by induce DNA replication stress,even genome instability.Activation of the cyclic GMP-AMP synthase(cGAS)mediates classical DNA sensing,is involved in genome instability,and is linked to various tumor development or therapy.However,the function of cGAS in gastric cancer remains elusive.In this study,the TCGA database and retrospective immunohistochemical analyses revealed substantially high cGAS expression in gastric cancer tissues and cell lines.By employing cGAS high-expression gastric cancer cell lines,including AGS and MKN45,ectopic silencing of cGAS caused a significant reduction in the proliferation of the cells,tumor growth,and mass in xenograft mice.Mechanistically,database analysis predicted a possible involvement of cGAS in the DNA damage response(DDR),further data through cells revealed protein interactions of the cGAS and MRE11-RAD50-NBN(MRN)complex,which activated cell cycle checkpoints,even increased genome instability in gastric cancer cells,thereby contributing to gastric cancer progression and sensitivity to treatment with DNA damaging agents.Furthermore,the upregulation of cGAS significantly exacerbated the prognosis of gastric cancer patients while improving radiotherapeutic outcomes.Therefore,we concluded that cGAS is involved in gastric cancer progression by fueling genome instability,implying that intervening in the cGAS pathway could be a practicable therapeutic approach for gastric cancer.
基金supported by the Guangxi Zhuang Autonomous Region Program of China(No.Z-C20220797)Guangxi Science and Technology Planning Project of China(No.Guike AD20297047)National Natural Science Foundation of China(No.81902849).
文摘Objective Abnormal expression of T-lymphokine-activated killer cell-originated protein kinase(TOPK)was reported to be closely related to the resistance of prostate cancer to radiotherapy and to targeted drug resistance in lung cancer.However,the role of TOPK inhibition in enhancing radiosensitivity of colorectal cancer(CRC)cells is unclear.This study aimed to evaluate the radiosensitization of TOPK knockdown in CRC cells.Methods The expression of TOPK was detected in CRC tissues by immunohistochemistry,and the effect of TOPK knockdown was detected in CRC cells by Western blotting.CCK-8 and clonogenic assays were used to detect the growth and clonogenic ability of CRC cells after TOPK knockdown combined with radiotherapy in CRC cells.Furthermore,proteomic analysis showed that the phosphorylation of TOPK downstream proteins changed after radiotherapy.DNA damage was detected by the comet assay.Changes in the DNA damage response signaling pathway were analyzed by Western blotting,and apoptosis was detected by flow cytometry.Results The expression of TOPK was significantly greater in CRC tissues at grades 2–4 than in those at grade 1.After irradiation,CRC cells with genetically silenced TOPK had shorter comet tails and reduced expression levels of DNA damage response-associated proteins,including phospho-cyclin-dependent kinase 1(p-CDK1),phospho-ataxia telangiectasia-mutated(p-ATM),poly ADP-ribose polymerase(PARP),and meiotic recombination 11 homolog 1(MRE11).Conclusions TOPK was overexpressed in patients with moderately to poorly differentiated CRC.Moreover,TOPK knockdown significantly enhanced the radiosensitivity of CRC cells by reducing the DNA damage response.
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.
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.
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.
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 NIH U19AI067769-9001 pilot research grant (H.H.)California Breast Cancer Research Program 16IB-0016 (H.H.)+1 种基金NIH RO1NS052528 (R.A.G.)the Ataxia-Telangiectasia Medical Research Foundation (Los Angeles,CA, (R.A.G.)).
文摘The DNA damage response(DDR)is a signal transduction pathway that decides the cell’s fate either to repair DNA damage or to undergo apoptosis if there is too much damage.Post-translational modifications modulate the assembly and activity of protein complexes during the DDR pathways.MicroRNAs(miRNAs)are emerging as a class of endogenous gene modulators that control protein levels,thereby adding a new layer of regulation to the DDR.In this review,we describe a new role for miRNAs in regulating the cellular response to DNA damage with a focus on DNA double-strand break damage.We also discuss the implications of miRNA’s role in the DDR to stem cells,including embryonic stem cells and cancer stem cells,stressing the potential applications for miRNAs to be used as sensitizers for cancer radiotherapy and chemotherapy.
基金supported by the grants from the National Program on Key Basic Research Project (Nos. 2013CB910300 and 2012CB910300 to H.P.)the International Science and Technology Cooperation Program of China (No. 2015DFA31680)+2 种基金the One Thousand Young Talent Program (to H.P.)the State Key Laboratory of Proteomics (No. SKLP-O201303 to C.Y.)the National Natural Science Foundation of China (No. 31371433 to H.P.)
文摘O-GlcNAcylation is an important post-translational modification and has been implicated in many fundamental cellular processes. Recent studies showed that O-linked N-acetylglucosamine (GlcNAc) transferase (OGT) mediated O-GlcNAcylation of histone H2B Ser 112 (H2B S 112 GlcNAcylation) plays an important role in gene transcription. However, the role of this histone modification in DNA damage response has not been studied yet. In this study, we found that OGT and OGT mediated H2B S112 GlcNAcylation are involved in DNA damage response for maintaining genomic stability and are required for resistance to many DNA-damaging and replication stress- inducing agents. OGT mediated H2B Sl12 GlcNAcylation increased locally upon the induction of double-strand breaks (DSBs), and depletion of OGT or overexpression of H2B S 112A mutant impaired homologous recombination (HR) and nonhomologous end-joining (NHEJ). Mechanistically, H2B Sl12 GlcNAcylation could bind Nijmegen breakage syndrome 1 (NBS1) and regulate NBS1 foci for- mation. Taken together, our results demonstrate a new function of histone O-GlcNAcylation in DNA damage response (DDR).
基金supported by Associazione Italiana Ricerca Cancro(IG201314102 to Silvana Pilotti).
文摘Background:Desmoplastic small round cell tumor(DSRCT)is a rare,aggressive,and poorly investigated simple sarcoma with a low frequency of genetic deregulation other than an Ewing sarcoma RNA binding protein 1(EWSR1)-Wilm’s tumor suppressor(WT1)translocation.We used whole-exome sequencing to interrogate six consecutive pretreated DSRCTs whose gene expression was previously investigated.Methods:DNA libraries were prepared from formalin-fixed,paraffin-embedded archival tissue specimens following the Agilent SureSelectXT2 target enrichment protocol and sequenced on Illumina NextSeq 500.Raw sequence data were aligned to the reference genome with Burrows-Wheeler Aligner algorithm.Somatic mutations and copy number alterations(CNAs)were identified using MuTect2 and EXCAVATOR2,respectively.Biological functions associated with altered genes were investigated through Ingenuity Pathway Analysis(IPA)software.Results:A total of 137 unique somatic mutations were identified:133 mutated genes were case-specific,and 2 were mutated in two cases but in different positions.Among the 135 mutated genes,27%were related to two biological categories:DNA damage-response(DDR)network that was also identified through IPA and mesenchymal-epithelial reverse transition(MErT)/epithelial-mesenchymal transition(EMT)already demonstrated to be relevant in DSRCT.The mutated genes in the DDR network were involved in various steps of transcription and particularly affected pre-mRNA.Half of these genes encoded RNA-binding proteins or DNA/RNA-binding proteins,which were recently rec-ognized as a new class of DDR players.CNAs in genes/gene families,involved in MErT/EMT and DDR,were recurrent across patients and mostly segregated in the MErT/EMT category.In addition,recurrent gains of regions in chromosome 1 involving many MErT/EMT gene families and loss of one arm or the entire chromosome 6 affecting relevant immune-regulatory genes were recorded.Conclusions:The emerging picture is an extreme inter-tumor heterogeneity,characterized by the concurrent deregulation of the DDR and MErT/EMT dynamic and plastic programs that could favour genomic instability and explain the refractory DSRCT profile.
基金supported by the National Natural Science Foundation of China (Grant Nos.31530016 and 31761133012)the National Basic Research Program of China (Grant Nos.2015CB910601 and 2017YFA0503900)the Shenzhen Science and Technology Innovation Commission (Grant No.JCYJ20170412113009742 awarded to XX),China
文摘DNA damage response(DDR) is essential for maintaining genome stability and protecting cells from tumorigenesis. Ubiquitin and ubiquitin-like modi?cations play an important role in DDR, from signaling DNA damage to mediating DNA repair. In this report, we found that the E3 ligase ring ?nger protein 126(RNF126) was recruited to UV laser micro-irradiation-induced stripes in a RNF8-dependent manner. RNF126 directly interacted with and ubiquitinated another E3 ligase, RNF168. Overexpression of wild type RNF126, but not catalytically-inactive mutant RNF126(CC229/232 AA), diminished ubiquitination of H2 A histone family member X(H2AX),and subsequent bleomycin-induced focus formation of total ubiquitin FK2, TP53-binding protein1(53 BP1), and receptor-associated protein 80(RAP80). Interestingly, both RNF126 overexpression and RNF126 downregulation compromised homologous recombination(HR)-mediated repair of DNA double-strand breaks(DSBs). Taken together, our ?ndings demonstrate that RNF126 negatively regulates RNF168 function in DDR and its appropriate cellular expression levels are essential for HR-mediated DSB repair.
基金supported by the National Natural Science Foundation of China(Nos.31770441,31971415).
文摘Decabrominated diphenyl ether(BDE-209)is generally utilized in multiple polymer materials as common brominated flame retardant.BDE-209 has been listed as persistent organic pollutants(POPs),which was considered to be reproductive toxin in the environment.But it still remains unclear about the effects of BDE-209 on DNA methylation and the inducedmale reproductive toxicity.Due to the extensive epigenetic regulation in germ line development,we hypothesize that BDE-209 exposure impacts the statue of DNA methylation in spermatocytes in vitro.Therefore,the mouse GC-2spd(GC-2)cells were used for the genome wide DNA methylation analysis after treated with 32μg/mL BDE-209 for 24 hr.The results showed that BDE-209 caused genomic methylation changes with 32,083 differentially methylated CpGs in GC-2 cells,including 16,164(50.38%)hypermethylated and 15,919(49.62%)hypomethylated sites.With integrated analysis ofDNAmethylation data and functional enrichment,we found that BDE-209 might affect the functional transcription in cell growth and sperm development by differential gene methylation.qRT-PCR validation demonstrated the involvement of p53-dependent DNA damage response in the GC-2 cells after BDE-209 exposure.In general,our findings indicated that BDE-209-induced genome wide methylation changes could be interrelated with reproductive dysfunction.This study might provide new insights into the mechanisms of male reproductive toxicity under the environmental exposure to BDE-209.
基金supported by the National Natural Science Foundation of China(Grant No.81571380)the Natural Science Foundation of Zhejiang Province–China(Grant No.LY16H080009)+2 种基金supported by the National Natural Science Foundation of China(Grant Nos.81130074,81420108017,and 81525010)funded by the National Key R&D Plan from the Ministry of Science and Technology of China(Grant No.SQ2016ZY05002341)partially supported by the Deutsche Forschungsgemeinschaft(DFG),Germany
文摘Maintenance of tissue-specific stem cells is vital for organ homeostasis and organismal longevity.Hematopoietic stem cells(HSCs) are the most primitive cell type in the hematopoietic system.They divide asymmetrically and give rise to daughter cells with HSC identity(selfrenewal) and progenitor progenies(differentiation),which further proliferate and differentiate into full hematopoietic lineages.Mammalian ageing process is accompanied with abnormalities in the HSC self-renewal and differentiation.Transcriptional changes and epigenetic modulations have been implicated as the key regulators in HSC ageing process.The DNA damage response(DDR)in the cells involves an orchestrated signaling pathway,consisting of cell cycle regulation,cell death and senescence,transcriptional regulation,as well as chromatin remodeling.Recent studies employing DNA repair-deficient mouse models indicate that DDR could intrinsically and extrinsically regulate HSC maintenance and play important roles in tissue homeostasis of the hematopoietic system.In this review,we summarize the current understanding of how the DDR determines the HSC fates and finally contributes to organismal ageing.
基金This work was supported by a grant from the Danish Cancer Society to ME(R167-A10932-17-S2)Theilgaard-Mönch K is supported by a clinical research fellowship and a center grant from the Novo Nordisk Foundation(grant no.100191,Novo Nordisk Foundation Center for Stem Cell Biology,DanStem+5 种基金grant no.NNF17CC0027852,KTM)by grants from the Danish Council for Strategic Research(grant no.133100153)the Danish Cancer Society(grant no.R72-A4572-13-S2,KTM)Børnecancerfonden(2016-0255)Læge Sofus Carl Emil Friis og Hustru Olga Doris Friis Foundation(Theilgaard-Mönch K)Tømrermester Jørgen Holm og Hustru Elisa,Brødrene Hartmans Fond,F.Hansen’s Mindelegat(Theilgaard-Mönch K).
文摘Resistance of cancer patients to DNA damaging radiation therapy and chemotherapy remains a major problem in the clinic.The current review discusses the molecular mechanisms of therapy resistance in acute myeloid leukemia(AML)conferred by cooperative chemotherapy-induced DNA damage response(DDR)and mutational activation of PI3K/AKT signaling.In addition,strategies to overcome resistance are discussed,with particular focus on studies underpinning the vast potential of therapies combining standard chemotherapy AML regimens with small molecule inhibitors targeting key regulatory hubs at the interface of DDR and oncogenic signaling pathways.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2021A1515011244,China)to Jinshan Tangthe National 111 Project of China(No.B13038,China)to Xinsheng Yao。
文摘DNA damage response(DDR)is a highly conserved genome surveillance mechanism that preserves cell viability in the presence of chemotherapeutic drugs.Hence,small molecules that inhibit DDR are expected to enhance the anti-cancer effect of chemotherapy.Through a recent chemical library screen,we identified shikonin as an inhibitor that strongly suppressed DDR activated by various chemotherapeutic drugs in cancer cell lines derived from different origins.Mechanistically,shikonin inhibited the activation of ataxia telangiectasia mutated(ATM),and to a lesser degree ATM and RAD3-related(ATR),two master upstream regulators of the DDR signal,through inducing degradation of ATM and ATR-interacting protein(ATRIP),an obligate associating protein of ATR,respectively.As a result of DDR inhibition,shikonin enhanced the anti-cancer effect of chemotherapeutic drugs in both cell cultures and in mouse models.While degradation of ATRIP is proteasome dependent,that of ATM depends on caspase-and lysosome-,but not proteasome.Overexpression of ATM significantly mitigated DDR inhibition and cell death induced by shikonin and chemotherapeutic drugs.These novel findings reveal shikonin as a pan DDR inhibitor and identify ATM as a primary factor in determining the chemo sensitizing effect of shikonin.Our data may facilitate the development of shikonin and its derivatives as potential chemotherapy sensitizers through inducing ATM degradation.