scholarly journals Nbs1‐mediated DNA damage repair pathway regulates haematopoietic stem cell development and embryonic haematopoiesis

2021 ◽  
Author(s):  
Yu Chen ◽  
Jie Sun ◽  
Zhenyu Ju ◽  
Zhao‐Qi Wang ◽  
Tangliang Li
Keyword(s):  
Dna Damage ◽  
Stem Cell ◽  
Dna Damage Repair ◽  
Cell Development ◽  
Haematopoietic Stem Cell ◽  
Repair Pathway ◽  
Damage Repair

scholarly journals O2: TOWARDS A LIVING BIOBANK OF SURGICALLY-RELEVANT 3-DIMENSIONAL GLIOBLASTOMA STEM CELL MODELS TO EVALUATE NOVEL THERAPEUTICS AND INTERROGATE INTRATUMOURAL HETEROGENEITY

2021 ◽  
Vol 108 (Supplement_1) ◽  
Author(s):  
O Rominiyi ◽  
A Vanderlinden ◽  
K Myers ◽  
N Gomez-Roman ◽  
D Dar ◽  
...  
Keyword(s):  
Dna Damage ◽  
Stem Cell ◽  
Cancer Biology ◽  
Residual Disease ◽  
Dna Damage Repair ◽  
Stem Cell Marker ◽  
Left Behind ◽  
Glioblastoma Stem Cell ◽  
Damage Repair ◽  
Intratumoural Heterogeneity

Abstract Introduction Glioblastoma is the most common cancer arising within the brain. Despite surgery, followed by DNA-damaging chemoradiotherapy, average survival remains between 12-15 months. Unacceptable survival rates underline the need to develop preclinical research models which recapitulate features underpinning therapeutic resistance in patients, such as intratumoural heterogeneity and treatment resistant glioblastoma stem cell (GSC) subpopulations which demonstrate elevated DNA damage response (DDR) activity. Method Tumour specimens from patients were used to generate 2D and 3D scaffold-based GSC models, with a range of preclinical survival and molecular assays used to interrogate cancer biology and assess therapeutic responses. Result We have developed a ‘living biobank’ of 20+ ex-vivo GSC models which reflect key clinicopathological diversity. These models include residual disease models based on careful macrodissection of rare en-blocpartial lobectomy specimens to liberate parallel GSC lines from the tumour core and adjacent infiltrated brain, to represent cells typically left behind after surgery. Therapeutic strategies targeting fundamental DDR processes demonstrate preclinical efficacy, for example dual inhibition of ATR and the FA DNA damage repair pathways elicits profound radiosensitisation (sensitiser enhancement ratio of 3.23 (3.03-3.49, 95%-CI)) with evidence of delayed DNA damage repair on single-cell gel electrophoresis. Finally, characterisation of our surgically-relevant resected and residual models reveals numerous divergent properties including elevated stem cell marker expression in residual models (p=0.0021), which may partially explain treatment resistance in disease left behind after surgery. Conclusion Our living biobank represents a useful resource for preclinical glioblastoma research and demonstrates the value of partnership between surgeons and laboratory-based scientists. Take-home message Our living biobank represents a useful resource for preclinical glioblastoma research and demonstrates the value of partnership between surgeons and laboratory-based scientists.

scholarly journals The Fanconi anemia DNA damage repair pathway in the spotlight for germline predisposition to colorectal cancer

2016 ◽  
Vol 24 (10) ◽  
pp. 1501-1505 ◽  
Author(s):  
Clara Esteban-Jurado ◽  
◽  
Sebastià Franch-Expósito ◽  
Jenifer Muñoz ◽  
Teresa Ocaña ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Dna Damage ◽  
Fanconi Anemia ◽  
Dna Damage Repair ◽  
Repair Pathway ◽  
Damage Repair

scholarly journals MicroRNA-146a-5p enhances radiosensitivity in hepatocellular carcinoma through replication protein A3-induced activation of the DNA repair pathway

2019 ◽  
Vol 316 (3) ◽  
pp. C299-C311 ◽  
Author(s):  
Jing Luo ◽  
Zhong-Zhou Si ◽  
Ting Li ◽  
Jie-Qun Li ◽  
Zhong-Qiang Zhang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Repair ◽  
Replication Protein ◽  
Repair Pathway ◽  
Related Factors ◽  
Damage Repair ◽  
Hcc Cells

Hepatocellular carcinoma (HCC) is known for its high mortality rate worldwide. Based on intensive studies, microRNA (miRNA) expression functions in tumor suppression. Therefore, we aimed to evaluate the contribution of miR-146a-5p to radiosensitivity in HCC through the activation of the DNA damage repair pathway by binding to replication protein A3 (RPA3). First, the limma package of R was performed to differentially analyze HCC expression chip, and regulative miRNA of RPA3 was predicted. Expression of miR-146a-5p, RPA3, and DNA damage repair pathway-related factors in tissues and cells was determined. The effects of radiotherapy on the expression of miR-146a-5p and RPA3 as well as on cell radiosensitivity, proliferation, cell cycle, and apoptosis were also assessed. The results showed that there exists a close correlation between miR-146a and the radiotherapy effect on HCC progression through regulation of RPA3 and the DNA repair pathway. The positive rate of ATM, pCHK2, and Rad51 in HCC tissues was higher when compared with that of the paracancerous tissues. SMMC-7721 and HepG2 cell proliferation were significantly inhibited following 8 Gy 6Mv dose. MiR-146a-5p restrained the expression of RPA3 and promoted the expression of relative genes associated with the DNA repair pathway. In addition, miR-146a-5p overexpression suppresses cell proliferation and enhances radiosensitivity and cell apoptosis in HCC cells. In conclusion, the present study revealed that miR-146a-5p could lead to the restriction of proliferation and the promotion of radiosensitivity and apoptosis in HCC cells through activation of DNA repair pathway and inhibition of RPA3.

ATM as a biomarker for DNA damage repair deficiency in pancreatic ductal adenocarcinoma.

2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 308-308
Author(s):  
Talia Golan ◽  
Sharon Halparin ◽  
Chani Stossel ◽  
Maria Raitses-Gurevich ◽  
Dikla Atias ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Protein Expression ◽  
Dna Damage Repair ◽  
Personal History ◽  
Nuclear Staining ◽  
Repair Pathway ◽  
Damage Repair ◽  
History Of ◽  
Atm Protein

308 Background: Approximately 15% of PDAC tumors display DNA damage repair (DDR) deficiency. Germline BRCA (gBRCA) mutation serves as a robust biomarker for the DDR deficiency. A subset of patients displays a similar clinical phenotype but lack the gBRCA mutation. Identification of these BRCA-like subset of patients remains a challenge and an alternative approach may include DDR functional assays. Here we suggest loss of the ATM protein as one of the biomarkers for the identification of the DDR deficiency signature in PDAC. Methods: Patients were identified from the Sheba pancreatic cancer database based on strong family/personal history of BRCA- associated cancers or a durable response to platinum containing regimens ( ≥ 6 month) or harboring germline/somatic mutations in the DNA repair pathway (excluding gBRCA mutation). Archival FFPE blocks of primary tumors/metastatic lesions were used to explore ATM protein expression by IHC. Nuclear staining was regarded as positive. Tumor infiltrating lymphocytes served as an internal positive control. ATM loss was defined as less than10% neoplastic nuclear staining at any intensity in the presence of positive lymphocytes staining. Results: We identified 53 patients with DDR deficiency phenotype between 2014-2016 from the Sheba PDAC database (n = 250). Median age at diagnosis was 65 years (46-81) and the majority were female (62%). 47% were diagnosed at stage I/II and 53% stage IV. In the subgroup of patients with DDR deficiency phenotype, 55% displayed a family history of BRCA-associated cancers, 19% had a personal history of malignancy and23% had known mutation in DNA repair pathway. 23/53 identified subjects have been analyzed to date. We identified 52% loss of ATM in the analyzed group (n = 23). Conclusions: Loss of ATM in an unselected PDAC population is 12% (H. Kim et al, 2014). Our data demonstrate that 52% of the highly selected subgroup of PDAC patients (DDR deficiency phenotype) was found to have loss of ATM protein expression, suggesting it to be one of the biomarker for DDR signature. Identification of these patients, based on ATM protein expression profile may lead to personalized treatment options.

scholarly journals NUSAP1 Enhances Drug Resistance By Binding to RAD51 through DNA Damage Repair Pathway in Chronic Lymphocytic Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 13-14
Author(s):  
Yang Han ◽  
Ya Zhang ◽  
Xinting Hu ◽  
Xiang Sun ◽  
Xin Wang
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Drug Resistance ◽  
Dna Damage Repair ◽  
Repair Process ◽  
Lymphocytic Leukemia ◽  
Repair Pathway ◽  
Damage Repair

Introduction: Enhanced DNA damage repair effect is an important mechanism for drug-resistance in chronic lymphocytic leukemia (CLL). Moreover, the ability of cancer cells to repair under radiation or chemotherapy drug induced DNA damage also serves as one of the mechanisms for therapy resistance. It is reported that nucleolar and spindle associated protein 1 (NUSAP1), a microtubule binding protein, has been involved in DNA damage repair process and plays important roles in the development, progression, and metastasis in several types of cancer. However, its role and mechanism in the development of CLL are still unclear. Methods: Expression levels of NUSAP1 mRNA and protein in CLL cell lines and patient specimens were detected by qRT-PCR and Western blot, and Kaplan-Meier survival curve and overall survival were analyzed by log-rank test. Peripheral blood samples from de novo CLL patients and healthy volunteers were collected with informed consents at the Department of Hematology in Shandong Provincial Hospital Affiliated to Shandong University (SPHASU). Microarray datasets GSE22762 were obtained from Gene Expression Omnibus. With altering NUSAP1 expression by lentivirus-transfected cells in vitro, the effects of NUSAP1 on cell proliferation, apoptosis and cycle were detected by CCK8, Annexin V-PE /7AAD staining and PI/RNase staining respectively. Bioinformatics analysis, luciferase reporter analysis, immunoprecipitation and were applied to discern and examine the relationship between NUSAP1 and its potential targets. Results: According to clinical specimens and bioinformatics analysis, the expression level of NUSAP1 gene in samples of CLL patients was significantly increased than that of healthy donors (P<0.05) (Figure A). Besides, the results indicated that the OS of patients with highly expressed NUSAP1 was significantly worse than in patients with low expression with the statistical analysis database GSE22762. mRNA and protein expression levels of NUSAP1 were significantly higher in CLL cell lines than in PBMCs from healthy donors (Figure C). Our findings indicated that NUSAP1 knockdown notably inhibited cell proliferation when compared with the Scramble group (Figure D). Moreover, the amounts of DNA fragmentation of the apoptotic cells were remarkably increased by NUSAP1 shRNA in MEC-1 and EHEB cells when compared with the Scramble group (Figure E). In addition, after knocking down NUSAP1, MEC-1 and EHEB cells were blocked in G0/G1 phase (Figure F). Moreover, addition to fludarabine or ibrutinib with shNUSAP1 group showed enhanced cytotoxicity in CLL cells (Figure G). The differential genes were analyzed via RNA-seq between Scramble and ShNUSAP1 group. Intriguingly, annotations of gene ontology (GO) analysis indicated that NUSAP1 was closely related to biological processes including cell cycle and response to drug. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that NUSAP1 were enriched in pathways in cancer, DNA replication and cell cycle. Gene set enrichment analysis (GSEA) implicated that NUSAP1 was functionally enriched in DNA replication, cell cycle and proteasome (Figure H). Immunofluorescence showed that NUSAP1 was mainly distributed in the cell nucleus, and the expression level of RAD51 was positively correlated with the change of NUSAP1 expression (Figure I). Surppression of NUSAP1 inhibited the action of proteins in DNA damage repair pathway (Figure J). Through COIP, NUSAP1 was identified to bind with RAD51 and play an important role in DNA damage repair pathway (Figure K). Hence, NUSAP1 participates in the DNA damage repair process and enhances the drug resistance in CLL. Conclusions: This study first demonstrated that the high expression of NUSAP1 in CLL patients is associated with poor prognosis through database analysis and experiments in vitro. Interference of NUSAP1 expression led to a slower CLL cell proliferation and a higher apoptosis rate, meanwhile induced the G1 phase arrest. Collectively, our findings demonstrated that NUSAP1 contributes to DNA damage repairing by binding to RAD51 and enhances drug resistance in CLL. Therefore, NUSAP1 is expected to be a potential target for the treatment of CLL with drug-resistance. Figure 1 Disclosures No relevant conflicts of interest to declare.

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