The role of BRCA1 in DNA repair and chemosensitivity

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 10606-10606 ◽  
Author(s):  
V. B. Sharma ◽  
A. W. Kurian ◽  
A. Feldman ◽  
J. M. Ford
Keyword(s):  
Dna Repair ◽  
Oxidative Dna Damage ◽  
Excision Repair ◽  
Brca1 Gene ◽  
Brca1 Protein ◽  
P53 Expression ◽  
Increased Risk ◽  
Uv C

10606 Introduction: The BRCA1 tumor suppressor protein has been implicated in many cellular processes, including several different DNA repair pathways. Inherited mutations in the BRCA1 gene result in an increased risk for developing breast and ovarian cancer. BRCA1 associated tumors are frequently estrogen receptor negative thus rendering them ineffective targets of hormonal manipulations. Therefore chemotherapy is the only treatment option available to patients with metastatic disease. Methods: Global genomic repair activity was detected by an immunoslotblot assay. UV-C and chemosensitivity was determined by the MTT assay. The comet assay was used to measure oxidative DNA damage (ODD). Results: Brca1 deficient cells demonstrate decreased global genomic repair independent of p53 expression. These cells are 3-fold more sensitive to UV-C radiation, 5-fold more sensitive to cisplatin, and 25-fold more sensitive to gemcitabine than Brca1 positive cells. The combination of cisplatin and gemcitabine is synergistic. This synergy is independent of Brca1 protein expression. In addition, the cholesterol lowering drug lovastatin is able mitigate the ODD caused by hydrogen peroxide. Reduced ODD is also observed in breast epithelial cells from high risk patients after 6 months of oral lovastatin use. Discussion: These results confirm our earlier findings that BRCA1 is involved in the nucleotide excision repair pathway. In addition, we demonstrate that this effect is independent of p53 expression. We also find that Brca1 deficient MMECs are more sensitive to UV-C, and the cytotoxic drugs cisplatin and gemcitabine. Cisplatin is known to cause DNA intra- and inter-strand crosslinks whereas gemcitabine is a nucleoside analog. The increased sensitivity of Brca1 deficient MMEC's to these agents supports the role of Brca1 in the different molecular pathways involved in their repair. In addition, we demonstrate that lovastatin can overcome ODD in vitro and in vivo and may be an effective agent to modify breast cancer risk for individuals at increased risk. No significant financial relationships to disclose.

Mutations in CREBBP and EP300 genes affect DNA repair of oxidative damage in Rubinstein-Taybi syndrome cells

2019 ◽  
Vol 41 (3) ◽  
pp. 257-266
Author(s):  
Ilaria Dutto ◽  
Claudia Scalera ◽  
Micol Tillhon ◽  
Giulio Ticli ◽  
Gianluca Passaniti ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Genome Stability ◽  
Oxidative Dna Damage ◽  
Excision Repair ◽  
Control Cell ◽  
Nuclear Antigen ◽  
Autosomal Dominant Disorder ◽  
Cell Extracts ◽  
Increased Risk

Abstract Rubinstein-Taybi syndrome (RSTS) is an autosomal-dominant disorder characterized by intellectual disability, skeletal abnormalities, growth deficiency and an increased risk of tumors. RSTS is predominantly caused by mutations in CREBBP or EP300 genes encoding for CBP and p300 proteins, two lysine acetyl-transferases (KAT) playing a key role in transcription, cell proliferation and DNA repair. However, the efficiency of these processes in RSTS cells is still largely unknown. Here, we have investigated whether pathways involved in the maintenance of genome stability are affected in lymphoblastoid cell lines (LCLs) obtained from RSTS patients with mutations in CREBBP or in EP300 genes. We report that RSTS LCLs with mutations affecting CBP or p300 protein levels or KAT activity, are more sensitive to oxidative DNA damage and exhibit defective base excision repair (BER). We have found reduced OGG1 DNA glycosylase activity in RSTS compared to control cell extracts, and concomitant lower OGG1 acetylation levels, thereby impairing the initiation of the BER process. In addition, we report reduced acetylation of other BER factors, such as DNA polymerase β and Proliferating Cell Nuclear Antigen (PCNA), together with acetylation of histone H3. We also show that complementation of CBP or p300 partially reversed RSTS cell sensitivity to DNA damage. These results disclose a mechanism of defective DNA repair as a source of genome instability in RSTS cells.

scholarly journals Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases in Colorectal Cancer Patients

2020 ◽  
Vol 21 (7) ◽  
pp. 2473 ◽  
Author(s):  
Pavel Vodicka ◽  
Marketa Urbanova ◽  
Pavol Makovicky ◽  
Kristyna Tomasova ◽  
Michal Kroupa ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Dna Damage ◽  
Dna Repair ◽  
Base Excision Repair ◽  
Oxidative Dna Damage ◽  
Excision Repair ◽  
Sporadic Colorectal Cancer ◽  
Base Excision ◽  
Colorectal Cancer Patients

Oxidative stress with subsequent premutagenic oxidative DNA damage has been implicated in colorectal carcinogenesis. The repair of oxidative DNA damage is initiated by lesion-specific DNA glycosylases (hOGG1, NTH1, MUTYH). The direct evidence of the role of oxidative DNA damage and its repair is proven by hereditary syndromes (MUTYH-associated polyposis, NTHL1-associated tumor syndrome), where germline mutations cause loss-of-function in glycosylases of base excision repair, thus enabling the accumulation of oxidative DNA damage and leading to the adenoma-colorectal cancer transition. Unrepaired oxidative DNA damage often results in G:C>T:A mutations in tumor suppressor genes and proto-oncogenes and widespread occurrence of chromosomal copy-neutral loss of heterozygosity. However, the situation is more complicated in complex and heterogeneous disease, such as sporadic colorectal cancer. Here we summarized our current knowledge of the role of oxidative DNA damage and its repair on the onset, prognosis and treatment of sporadic colorectal cancer. Molecular and histological tumor heterogeneity was considered. Our study has also suggested an additional important source of oxidative DNA damage due to intestinal dysbiosis. The roles of base excision repair glycosylases (hOGG1, MUTYH) in tumor and adjacent mucosa tissues of colorectal cancer patients, particularly in the interplay with other factors (especially microenvironment), deserve further attention. Base excision repair characteristics determined in colorectal cancer tissues reflect, rather, a disease prognosis. Finally, we discuss the role of DNA repair in the treatment of colon cancer, since acquired or inherited defects in DNA repair pathways can be effectively used in therapy.

Role of vitamin C in gastric cancer

2018 ◽  
Vol 01 (1) ◽  
Author(s):  
Takalkar U Vidyadhar
Keyword(s):  
Gastric Cancer ◽  
Vitamin C ◽  
Gastric Juice ◽  
Oxidative Dna Damage ◽  
Preventive Measure ◽  
Dietary Factors ◽  
Preventive Strategy ◽  
H Pylori

Gastric cancer is a multifactorial disease with complex interplay of environmental and genetic factors. Helicobacter pylori (H. pylori) infestation has been identified as the most important etiological agent in the pathogenesis of gastric cancer. Also, the role of dietary factors that is low consumption of fruits and vegetables have been found to be associated with gastric cancer. Among the dietary factors, antioxidants especially vitamin C has been found to confer the strongest protection against gastric cancer. Its anti-proliferative and pro-apoptotic action has been suggested in vitro. Because of its antioxidant activity, it protects cells against oxidative DNA damage caused by toxic effects of reactive oxygen species. It also inhibits production of carcinogenic N-nitroso compound in the stomach. The person with H. pylori infection has low levels of vitamin C in their gastric juice and levels of vitamin C normalizes on eradication of H. pylori. Vitamin C levels are high in gastric mucosa and gastric juice, sometimes more than that of in plasma. But gastric pathological conditions cause lowered secretion of vitamin C into gastric juice. Effect of H. pylori on vitamin C in gastric juice is reversible and on eradication of H. pylori, it returns to normal level. Hence, eradication of H. pylori and chemoprevention with antioxidant supplementation will be an effective preventive strategy to reduce the incidence of gastric cancer and related mortality. Vitamin C and gastric cancer is an area of potential interest for researchers as a preventive measure. Keywords: Vitamin C, H. pylori, gastric cancer.

scholarly journals The Novel Role of PGC1α in Bone Metabolism

2021 ◽  
Vol 22 (9) ◽  
pp. 4670
Author(s):  
Cinzia Buccoliero ◽  
Manuela Dicarlo ◽  
Patrizia Pignataro ◽  
Francesco Gaccione ◽  
Silvia Colucci ◽  
...  
Keyword(s):  
Bone Metabolism ◽  
Osteoblastic Differentiation ◽  
In Vivo Studies ◽  
Peroxisome Proliferator ◽  
Sirtuin 3 ◽  
Peroxisome Proliferator Activated Receptor ◽  
Increased Risk

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) is a protein that promotes transcription of numerous genes, particularly those responsible for the regulation of mitochondrial biogenesis. Evidence for a key role of PGC1α in bone metabolism is very recent. In vivo studies showed that PGC1α deletion negatively affects cortical thickness, trabecular organization and resistance to flexion, resulting in increased risk of fracture. Furthermore, in a mouse model of bone disease, PGC1α activation stimulates osteoblastic gene expression and inhibits atrogene transcription. PGC1α overexpression positively affects the activity of Sirtuin 3, a mitochondrial nicotinammide adenina dinucleotide (NAD)-dependent deacetylase, on osteoblastic differentiation. In vitro, PGC1α overexpression prevents the reduction of mitochondrial density, membrane potential and alkaline phosphatase activity caused by Sirtuin 3 knockdown in osteoblasts. Moreover, PGC1α influences the commitment of skeletal stem cells towards an osteogenic lineage, while negatively affects marrow adipose tissue accumulation. In this review, we will focus on recent findings about PGC1α action on bone metabolism, in vivo and in vitro, and in pathologies that cause bone loss, such as osteoporosis and type 2 diabetes.

scholarly journals Spleen Tyrosine Kinase Inhibition Modulates p53 Activity

2017 ◽  
Vol 10 ◽  
pp. 117906601773156 ◽  
Author(s):  
Mohammad Althubiti
Keyword(s):  
Tyrosine Kinase ◽  
Survival Rates ◽  
Lymphocytic Leukemia ◽  
Spleen Tyrosine Kinase ◽  
Ht1080 Cell ◽  
P53 Expression ◽  
Chemical Inhibitors ◽  
Dependent Mechanism

Spleen tyrosine kinase (SYK) is a cytoplasmic enzyme that promotes survival and proliferation of B cells. SYK inhibition has shown promising results in the treatment of arthritis and chronic lymphocytic leukemia (CLL). However, in other context, it has been shown that SYK overexpression in epithelial cancer cells induced senescence in p53-dependent mechanism, which underscored its antineoplastic activity in vitro. Here, we show that SYK was induced in response of DNA damage in parallel with p53 levels. In addition, using chemical inhibitors of SYK reduced p53 levels in HCT116 and HT1080 cell lines, which underlines the role of SYK inhibition on p53 activity. Furthermore, SYK inhibition modulated the cell growth, which resulted in a decreasing in cell death. Interestingly, SYK expression showed a positive prognosis in patients with solid tumors in correlations with their survival rates, as expected negative correlation was seen between SYK expression and survival rate of patients with CLL. In conclusion, these findings demonstrate that SYK inhibition modulates p53 expression and activity in HCT116 and HT1080 cells. Reconsidering using of SYK inhibitors in clinical setting in the future should be evaluated carefully in accordance with these findings to prevent the formation of secondary malignancies.

scholarly journals Genotoxicity and inflammatory potential of stainless steel welding fume particles: an in vitro study on standard vs Cr(VI)-reduced flux-cored wires and the role of released metals

2021 ◽  
Author(s):  
Sarah McCarrick ◽  
Valentin Romanovski ◽  
Zheng Wei ◽  
Elin M. Westin ◽  
Kjell-Arne Persson ◽  
...  
Keyword(s):  
Dna Damage ◽  
In Vitro Study ◽  
Human Monocyte ◽  
Welding Fumes ◽  
Welding Fume ◽  
Increased Risk ◽  
Underlying Mechanisms ◽  
Cored Wires

AbstractWelders are daily exposed to various levels of welding fumes containing several metals. This exposure can lead to an increased risk for different health effects which serves as a driving force to develop new methods that generate less toxic fumes. The aim of this study was to explore the role of released metals for welding particle-induced toxicity and to test the hypothesis that a reduction of Cr(VI) in welding fumes results in less toxicity by comparing the welding fume particles of optimized Cr(VI)-reduced flux-cored wires (FCWs) to standard FCWs. The welding particles were thoroughly characterized, and toxicity (cell viability, DNA damage and inflammation) was assessed following exposure to welding particles as well as their released metal fraction using cultured human bronchial epithelial cells (HBEC-3kt, 5–100 µg/mL) and human monocyte-derived macrophages (THP-1, 10–50 µg/mL). The results showed that all Cr was released as Cr(VI) for welding particles generated using standard FCWs whereas only minor levels (< 3% of total Cr) were released from the newly developed FCWs. Furthermore, the new FCWs were considerably less cytotoxic and did not cause any DNA damage in the doses tested. For the standard FCWs, the Cr(VI) released in cell media seemed to explain a large part of the cytotoxicity and DNA damage. In contrast, all particles caused rather similar inflammatory effects suggesting different underlying mechanisms. Taken together, this study suggests a potential benefit of substituting standard FCWs with Cr(VI)-reduced wires to achieve less toxic welding fumes and thus reduced risks for welders.

Stable and specific association between the yeast recombination and DNA repair proteins RAD1 and RAD10 in vitro

1992 ◽  
Vol 12 (7) ◽  
pp. 3041-3049
Author(s):  
L Bardwell ◽  
A J Cooper ◽  
E C Friedberg
Keyword(s):  
Dna Repair ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Specific Interaction ◽  
Mitotic Recombination ◽  
Nucleotide Excision ◽  
Specific Association ◽  
Recombination Pathway ◽  
Cloned Gene

The RAD1 and RAD10 genes of Saccharomyces cerevisiae are two of at least seven genes which are known to be required for damage-specific recognition and/or damage-specific incision of DNA during nucleotide excision repair. RAD1 and RAD10 are also involved in a specialized mitotic recombination pathway. We have previously reported the purification of the RAD10 protein to homogeneity (L. Bardwell, H. Burtscher, W. A. Weiss, C. M. Nicolet, and E. C. Friedberg, Biochemistry 29:3119-3126, 1990). In the present studies we show that the RAD1 protein, produced by in vitro transcription and translation of the cloned gene, specifically coimmunoprecipitates with the RAD10 protein translated in vitro or purified from yeast. Conversely, in vitro-translated RAD10 protein specifically coimmunoprecipitates with the RAD1 protein. The sites of this stable and specific interaction have been mapped to the C-terminal regions of both polypeptides. This portion of RAD10 protein is evolutionarily conserved. These results are the first biochemical evidence of a specific association between any eukaryotic proteins genetically identified as belonging to a recombination or DNA repair pathway and suggest that the RAD1 and RAD10 proteins act at the same or consecutive biochemical steps in both nucleotide excision repair and mitotic recombination.

Abstract 237: PRMT1-p53-Slug Axis Regulates Epicardial EMT and Ventricular Development

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Olan Jackson-Weaver ◽  
Jian Wu ◽  
Yongchao Gou ◽  
Yibu Chen ◽  
Meng Li ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Heart Development ◽  
Cultured Cells ◽  
Migration And Invasion ◽  
P53 Expression ◽  
Epicardial Cells ◽  
Coronary Blood Vessels

Rationale: Epicardial epithelial-to-mesenchymal trasition (EMT) is a vital process in embryonic heart development. During EMT, epicardial cells acquire migratory and invasive properties, and differentiate into new cell types, including cardiac fibroblasts and coronary smooth muscle cells. Non-histone protein methylation is an emerging modulator of cell signaling. We have recently established a role for protein arginine methyltransferase-1 (PRMT1) in TGF-β-induced EMT in cultured cells. Objective: To determine the role of PRMT1 in epicardial EMT. Methods and Results: We investigated the role of PRMT1 in epicardial EMT in mouse epicardial cells. Embryonic day 9.5 (E9.5) tamoxifen administration of WT1-Cre ERT ;PRMT1 fl/fl ;ROSA-YFP fl/fl mouse embryos was used to delete PRMT1 in the epicardium. Epicardial PRMT1 deletion led to reduced epicardial migration into the myocardium, a thinner compact myocardial layer, and dilated coronary blood vessels at E15.5. Using the epicardial cell line MEC1, we found that PRMT1 siRNA prevented the increase in mesenchymal proteins Slug and Fibronectin and the decrease in epithelial protein E-Cadherin during TGF-β treatment-induced EMT. PRMT1 siRNA also reduced the migration and invasion of MEC1 cells. We further identified that PRMT1 siRNA also increased the expression of p53, a key regulator of the Slug degradation pathway. PRMT1 siRNA increases p53 expression by decreasing p53 degradation, and shifted p53 localization to the cytoplasm. In vitro methylation assays further demonstrated that PRMT1 methylates p53. Knockdown of p53 increased Slug levels and enhanced EMT, establishing p53 as a regulator of epicardial EMT through controlling Slug expression. Furthermore, RNAseq experiments in MEC1 cells demonstrated that 40% (545/1,351) of TGF-β-induced transcriptional changes were prevented by PRMT1 siRNA. Furthermore, when p53 and PRMT1 were simultaneously knocked down, TGF-β induced transcriptional control of 37% (201/545) of these PRMT1-dependent genes was restored. Conclusions: The PRMT1-p53-Slug pathway is necessary for epicardial EMT in cultured MEC1 cells as well as in the epicardium in vivo . Epicardial PRMT1 is required for the development of compact myocardium and coronary blood vessels.

scholarly journals The FAM171A2 gene is a key regulator of progranulin expression and modifies the risk of multiple neurodegenerative diseases

2020 ◽  
Vol 6 (43) ◽  
pp. eabb3063
Author(s):  
Wei Xu ◽  
Si-Da Han ◽  
Can Zhang ◽  
Jie-Qiong Li ◽  
Yan-Jiang Wang ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Genome Wide Association Study ◽  
In Vitro Study ◽  
Genome Wide ◽  
A Genome ◽  
Increased Risk ◽  
Pathophysiological Role ◽  
Independent Cohort

Progranulin (PGRN) is a secreted pleiotropic glycoprotein associated with the development of common neurodegenerative diseases. Understanding the pathophysiological role of PGRN may help uncover biological underpinnings. We performed a genome-wide association study to determine the genetic regulators of cerebrospinal fluid (CSF) PGRN levels. Common variants in region of FAM171A2 were associated with lower CSF PGRN levels (rs708384, P = 3.95 × 10−12). This was replicated in another independent cohort. The rs708384 was associated with increased risk of Alzheimer’s disease, Parkinson’s disease, and frontotemporal dementia and could modify the expression of the FAM171A2 gene. FAM171A2 was considerably expressed in the vascular endothelium and microglia, which are rich in PGRN. The in vitro study further confirmed that the rs708384 mutation up-regulated the expression of FAM171A2, which caused a decrease in the PGRN level. Collectively, genetic, molecular, and bioinformatic findings suggested that FAM171A2 is a key player in regulating PGRN production.

scholarly journals Exploiting GRK2 Inhibition as a Therapeutic Option in Experimental Cancer Treatment: Role of p53-Induced Mitochondrial Apoptosis

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3530
Author(s):  
Jessica Gambardella ◽  
Antonella Fiordelisi ◽  
Gaetano Santulli ◽  
Michele Ciccarelli ◽  
Federica Andrea Cerasuolo ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cancer Cell ◽  
Nude Mice ◽  
Specific Inhibitor ◽  
Cancer Cell Proliferation ◽  
In Vivo Models ◽  
P53 Expression

The involvement of GRK2 in cancer cell proliferation and its counter-regulation of p53 have been suggested in breast cancer even if the underlying mechanism has not yet been elucidated. Furthermore, the possibility to pharmacologically inhibit GRK2 to delay cancer cell proliferation has never been explored. We investigated this possibility by setting up a study that combined in vitro and in vivo models to underpin the crosstalk between GRK2 and p53. To reach this aim, we took advantage of the different expression of p53 in cell lines of thyroid cancer (BHT 101 expressing p53 and FRO cells, which are p53-null) in which we overexpressed or silenced GRK2. The pharmacological inhibition of GRK2 was achieved using the specific inhibitor KRX-C7. The in vivo study was performed in Balb/c nude mice, where we treated BHT-101 or FRO-derived tumors with KRX-C7. In our in vitro model, FRO cells were unaffected by GRK2 expression levels, whereas BHT-101 cells were sensitive, thus suggesting a role for p53. The regulation of p53 by GRK2 is due to phosphorylative events in Thr-55, which induce the degradation of p53. In BHT-101 cells, the pharmacologic inhibition of GRK2 by KRX-C7 increased p53 levels and activated apoptosis through the mitochondrial release of cytochrome c. These KRX-C7-mediated events were also confirmed in cancer allograft models in nude mice. In conclusion, our data showed that GRK2 counter-regulates p53 expression in cancer cells through a kinase-dependent activity. Our results further corroborate the anti-proliferative role of GRK2 inhibitors in p53-sensitive tumors and propose GRK2 as a therapeutic target in selected cancers.

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