In Vitro Senescence of Rat Mesenchymal Stem Cells is Accompanied by Downregulation of Stemness-Related and DNA Damage Repair Genes

Class III receptor tyrosine kinase (RTK) inhibitors targeting mainly FLT3 or c-KIT have not been well studied in lung cancer. To identify a small molecule potentially targeting class III RTK, we synthesized novel small molecule compounds and identified 5-(4-bromophenyl)-N-(naphthalen-1-yl) oxazol-2-amine (AIU2001) as a novel class III RKT inhibitor. In an in vitro kinase profiling assay, AIU2001 inhibited the activities of FLT3, mutated FLT3, FLT4, and c-KIT of class III RTK, and the proliferation of NSCLC cells in vitro and in vivo. AIU2001 induced DNA damage, reactive oxygen species (ROS) generation, and cell cycle arrest in the G2/M phase. Furthermore, AIU2001 suppressed the DNA damage repair genes, resulting in the ‘BRCAness’/‘DNA-PKness’ phenotype. The mRNA expression level of STAT5 was downregulated by AIU2001 treatment and knockdown of STAT5 inhibited the DNA repair genes. Our results show that compared to either drug alone, the combination of AIU2001 with a poly (ADP-ribose) polymerase (PARP) inhibitor olaparib or irradiation showed synergistic efficacy in H1299 and A549 cells. Hence, our findings demonstrate that AIU2001 is a candidate therapeutic agent for NSCLC and combination therapies with AIU2001 and a PARP inhibitor or radiotherapy may be used to increase the therapeutic efficacy of AIU2001 due to inhibition of DNA damage repair.

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Altered expression of DNA damage repair genes in the brain tissue of mice conceived by in vitro fertilization

MHR Basic science of reproductive medicine ◽

10.1093/molehr/gaaa010 ◽

2020 ◽

Vol 26 (3) ◽

pp. 141-153

Author(s):

Minhao Hu ◽

Yiyun Lou ◽

Shuyuan Liu ◽

Yuchan Mao ◽

Fang Le ◽

...

Keyword(s):

Dna Methylation ◽

Dna Damage ◽

Brain Tissue ◽

Dna Damage Repair ◽

Damage Repair ◽

Gene And Protein Expression ◽

The Brain ◽

Repair Genes

Abstract Our previous study revealed a higher incidence of gene dynamic mutation in newborns conceived by IVF, highlighting that IVF may be disruptive to the DNA stability of IVF offspring. However, the underlying mechanisms remain unclear. The DNA damage repair system plays an essential role in gene dynamic mutation and neurodegenerative disease. To evaluate the long-term impact of IVF on DNA damage repair genes, we established an IVF mouse model and analyzed gene and protein expression levels of MSH2, MSH3, MSH6, MLH1, PMS2, OGG1, APEX1, XPA and RPA1 and also the amount of H2AX phosphorylation of serine 139 which is highly suggestive of DNA double-strand break (γH2AX expression level) in the brain tissue of IVF conceived mice and their DNA methylation status using quantitative real-time PCR, western blotting and pyrosequencing. Furthermore, we assessed the capacity of two specific non-physiological factors in IVF procedures during preimplantation development. The results demonstrated that the expression and methylation levels of some DNA damage repair genes in the brain tissue of IVF mice were significantly changed at 3 weeks, 10 weeks and 1.5 years of age, when compared with the in vivo control group. In support of mouse model findings, oxygen concentration of in vitro culture environment was shown to have the capacity to modulate gene expression and DNA methylation levels of some DNA damage repair genes. In summary, our study indicated that IVF could bring about long-term alterations of gene and protein expression and DNA methylation levels of some DNA damage repair genes in the brain tissue and these alterations might be resulted from the different oxygen concentration of culture environment, providing valuable perspectives to improve the safety and efficiency of IVF at early embryonic stage and also throughout different life stages.

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Mutant MEG3 Enhances the Activity of Telomerase by Increasing DNA Damage Repair in Human Liver Cancer Stem Cells

10.21203/rs.3.rs-486093/v1 ◽

2021 ◽

Author(s):

Shuting Song ◽

Sijie Xie ◽

Rushi Qin ◽

Yanan Lu ◽

Liyan Wang ◽

...

Keyword(s):

Stem Cells ◽

Dna Damage ◽

Cancer Stem Cells ◽

Liver Cancer ◽

Human Liver ◽

Dna Damage Repair ◽

Liver Cancer Stem Cells ◽

Damage Repair ◽

Human Liver Cancer

Abstract Background: Long noncoding RNAs have recently considered as central regulators in diverse biological processes and emerged as vital players controlling tumorigenesis. Although wild MEG3 acts as a suppressor in several cancers, the function of mutant MEG3 is also unclear during tumorigenesis.Methods: Lentivalus infection,RT-PCR,Western blotting and tumorigenesis test in vitro and in vivo were performed.Results: our results suggest that mutant MEG3 promotes the growth of human liver cancer stem cells in vivo and in vitro.Mechanistically, our results show that mutant MEG3 enhances acetylation modification of HistoneH4 on K16.Then, mutant MEG3 enhances the expression of SETD2 dependent on H4K16Ac.Moreover, mutant MEG3 increases the DNA damage repair through SETD2.Ultimately, mutant MEG3 increases the telomeras activity dependent on DNA damage repair.Strikingly,TERT determines the cancerous function of mutant MEG3 in liver cancer stem cells. Therefore, we shed light on the fact that targeting mutant MEG3 could be a viable approach for cancer treatment.Conclusions: these observations will play an important role in finding effective tumor treatment targets.

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Leukemia Stem Cells Demonstrate Increased DNA Damage Repair and Chemoresistance in Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2020-136076 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 2-2

Author(s):

Grace Egan ◽

Geethu Emily Thomas ◽

Parasvi Patel ◽

Rose Hurren ◽

Neil MacLean ◽

...

Keyword(s):

Stem Cells ◽

Dna Damage ◽

Dna Repair ◽

Stem Cell ◽

Dna Damage Repair ◽

Leukemia Stem Cells ◽

Over Expression ◽

Γh2ax Foci ◽

Damage Repair ◽

Repair Genes

While most patients with AML achieve remission with standard induction chemotherapy, the majority ultimately relapse. Relapsed AML is due, at least in part, to the persistence of chemoresistant leukemia stem cells (LSCs). The mechanisms of chemoresistance in LSCs are not fully understood. Here, we explored DNA damage repair in LSCs. 8227 cells are low passage primary AML cells that maintain a hierarchical organization with functionally defined stem cells in the CD34+CD38- fraction. We FACS sorted 8227 cells into stem and bulk fractions and measured expression of DNA repair genes. LSCs were primed for DNA repair with increased expression of genes associated with homologous recombination (RAD51, XRCC2, XRCC3) and non-homologous end joining (XRCC4, XRCC5, PRKDC). Next, we treated the cell fractions with daunorubicin, an intercalating anthracycline that causes double stranded breaks. DNA damage and repair were evaluated by measuring foci of 53BP1, RAD51 and γH2AX by fluorescent microscopy and quantified using image J. Compared to bulk cells, 8227 stem cells demonstrated enhanced DNA damage repair with increased foci of 53BP1 and RAD51 and decreased γH2AX foci, compared to their basal levels. Similar findings were noted after exposing the stem and bulk cells to radiation. We recently discovered that the metabolic enzyme hexokinase 2 (HK2) localizes to the nucleus to maintain stem cell number and function. Therefore, we selectively over-expressed HK2 in the nucleus of 8227 and NB4 cells by tagging HK2 with a nuclear localizing sequence (PAAKRVKLD). We confirmed selective over-expression of HK2 in the nucleus by immunoblotting and confocal microscopy. Over-expressing HK2 increased stem cell function as shown by clonogenic growth assays and engraftment into mouse marrow. We then treated these cells with daunorubicin and measured DNA damage repair. Over-expression of nuclear HK2 increased 53BP1 and RAD51 foci with decreased γH2AX foci, similar to the phenotype observed in LSCs. In addition, over-expression of nuclear HK2 conferred resistance to daunorubicin as measured by clonogenic growth assays. In summary, LSCs appear to be primed for DNA repair with increased levels of DNA damage repair genes. After exposure to chemotherapy and radiation, LSCs have increased repair of double strand DNA breaks compared to more differentiated blasts. This accelerated DNA damage repair may partly explain the increased chemoresistance seen in LSCs. Disclosures Schimmer: Takeda:Honoraria, Research Funding;Novartis:Honoraria;Jazz:Honoraria;AbbVie Pharmaceuticals:Other: owns stock ;Otsuka:Honoraria;Medivir AB:Research Funding.

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Faculty Opinions recommendation of Deficiencies in DNA damage repair limit the function of haematopoietic stem cells with age.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1087486.540536 ◽

2007 ◽

Author(s):

Lucio Comai

Keyword(s):

Stem Cells ◽

Dna Damage ◽

Dna Damage Repair ◽

Haematopoietic Stem Cells ◽

Damage Repair

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P57.04 Mutations of DNA Damage Repair Genes in Lung Adenocarcinoma and Their Association with Actionable Alterations

Journal of Thoracic Oncology ◽

10.1016/j.jtho.2021.01.948 ◽

2021 ◽

Vol 16 (3) ◽

pp. S534-S535

Author(s):

Z. Yu ◽

S. Dang ◽

J. Zhang ◽

J. Duan ◽

S. Chen ◽

...

Keyword(s):

Dna Damage ◽

Lung Adenocarcinoma ◽

Dna Damage Repair ◽

Damage Repair ◽

Repair Genes

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PAICS contributes to gastric carcinogenesis and participates in DNA damage response by interacting with histone deacetylase 1/2

Cell Death and Disease ◽

10.1038/s41419-020-2708-5 ◽

2020 ◽

Vol 11 (7) ◽

Author(s):

Nan Huang ◽

Chang Xu ◽

Liang Deng ◽

Xue Li ◽

Zhixuan Bian ◽

...

Keyword(s):

Dna Damage ◽

Histone Deacetylase ◽

Dna Damage Response ◽

De Novo ◽

Dna Damage Repair ◽

Histone Deacetylase 1 ◽

Damage Repair ◽

Damage Response

AbstractPhosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.

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Differentiation of Human Induced Pluripotent or Embryonic Stem Cells Decreases the DNA Damage Repair by Homologous Recombination

Stem Cell Reports ◽

10.1016/j.stemcr.2017.10.002 ◽

2017 ◽

Vol 9 (5) ◽

pp. 1660-1674 ◽

Cited By ~ 12

Author(s):

Kalpana Mujoo ◽

Raj K. Pandita ◽

Anjana Tiwari ◽

Vijay Charaka ◽

Sharmistha Chakraborty ◽

...

Keyword(s):

Stem Cells ◽

Dna Damage ◽

Embryonic Stem Cells ◽

Homologous Recombination ◽

Dna Damage Repair ◽

Embryonic Stem ◽

Damage Repair ◽

Induced Pluripotent

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DISTRIBUTION OF DNA DAMAGE REPAIR GENE POLYMORPHISM hOGG1, XRCC1 and p53 AMONG SICKLE CELL DISEASE PATIENTS IN INDIA

Mediterranean Journal of Hematology and Infectious Diseases ◽

10.4084/mjhid.2015.046 ◽

2015 ◽

Vol 7 ◽

pp. e2015046 ◽

Cited By ~ 1

Author(s):

Sudhansu Sekhar Nishank

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Sickle Cell Disease ◽

Gene Polymorphisms ◽

Clinical Effect ◽

Dna Damage Repair ◽

Cell Disease ◽

Repair Gene ◽

Damage Repair ◽

Repair Genes

Background– Defect in DNA damage repair genes due to oxidative stress predispose the humans to malignancies. There are many cases of association of malignancies with sickle cell disease patients (SCD) throughout the world, the molecular cause of which has never been investigated. DNA damage repair genes such as hOGG1, XRCC1 and p53 play significant role in repair of DNA damage during oxidative stress but the distribution and clinical effect of these genes are not known till date in SCD patients who are associated with oxidative stress related clinical complications. Objective – The aim of the study was to characterize the distribution and clinical effect of DNA damage gene polymorphisms p53 (codon 72 Arg> Pro), hOGG1 (codon 326 Ser>Cyst) and XRCC1 (codons 194 Arg>Trp, codon 280 Arg> His, codon 399 Arg> Gln) among SCD patients of central India. Methods- A case control study of 250 SCD patients and 250 normal individuals were investigated by PCR-RFLP techniques. Result- The prevalence of mutant alleles of hOGG1 gene, XRCC1 codon 280 Arg>His were found to be significantly high among SCD patients as compared to controls. However, SCD patients did not show clinical association with any of these DNA repair gene polymorphisms. Conclusion- This indicates that hOGG1, p53 and XRCC1 gene polymorphisms may not have any clinical impact among SCD patients in India.

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SIRT7-mediated ATM deacetylation is essential for its deactivation and DNA damage repair

Science Advances ◽

10.1126/sciadv.aav1118 ◽

2019 ◽

Vol 5 (3) ◽

pp. eaav1118 ◽

Cited By ~ 19

Author(s):

Ming Tang ◽

Zhiming Li ◽

Chaohua Zhang ◽

Xiaopeng Lu ◽

Bo Tu ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Repair ◽

Class Iii ◽

Ataxia Telangiectasia Mutated ◽

Damage Repair ◽

Damage Response ◽

Late Stages

The activation of ataxia-telangiectasia mutated (ATM) upon DNA damage involves a cascade of reactions, including acetylation by TIP60 and autophosphorylation. However, how ATM is progressively deactivated after completing DNA damage repair remains obscure. Here, we report that sirtuin 7 (SIRT7)–mediated deacetylation is essential for dephosphorylation and deactivation of ATM. We show that SIRT7, a class III histone deacetylase, interacts with and deacetylates ATM in vitro and in vivo. In response to DNA damage, SIRT7 is mobilized onto chromatin and deacetylates ATM during the late stages of DNA damage response, when ATM is being gradually deactivated. Deacetylation of ATM by SIRT7 is prerequisite for its dephosphorylation by its phosphatase WIP1. Consequently, depletion of SIRT7 or acetylation-mimic mutation of ATM induces persistent ATM phosphorylation and activation, thus leading to impaired DNA damage repair. Together, our findings reveal a previously unidentified role of SIRT7 in regulating ATM activity and DNA damage repair.

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