scholarly journals Bovine Lactoferrin Pre-Treatment Induces Intracellular Killing of AIEC LF82 and Reduces Bacteria-Induced DNA Damage in Differentiated Human Enterocytes

2019 ◽  
Vol 20 (22) ◽  
pp. 5666 ◽  
Author(s):  
Maria Stefania Lepanto ◽  
Luigi Rosa ◽  
Antimo Cutone ◽  
Mellani Jinnett Scotti ◽  
Antonietta Lucia Conte ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cellular Localization ◽  
Culture Medium ◽  
Intracellular Survival ◽  
Bovine Lactoferrin ◽  
Natural Immunity ◽  
Cell Surface Molecule ◽  
Dna Damages ◽  
Pre Treatment ◽  
The Moment

LF82, a prototype of adherent-invasive E. coli (AIEC), is able to adhere to, invade, survive and replicate into intestinal epithelial cells. LF82 is able to enhance either its adhesion and invasion by up-regulating carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM-6), the main cell surface molecule for bacterial adhesion, and its intracellular survival by inducing host DNA damage, thus blocking the cellular cycle. Lactoferrin (Lf) is a multifunctional cationic glycoprotein of natural immunity, exerting an anti-invasive activity against LF82 when added to Caco-2 cells at the moment of infection. Here, the infection of 12 h Lf pre-treated Caco-2 cells was carried out at a time of 0 or 3 or 10 h after Lf removal from culture medium. The effect of Lf pre-treatment on LF82 invasiveness, survival, cell DNA damage, CEACAM-6 expression, apoptosis induction, as well as on Lf subcellular localization, has been evaluated. Lf, even if removed from culture medium, reduced LF82 invasion and survival as well as bacteria-induced DNA damage in Caco-2 cells independently from induction of apoptosis, modulation of CEACAM-6 expression and Lf sub-cellular localization. At our knowledge, this is the first study showing that the sole Lf pre-treatment can activate protective intracellular pathways, reducing LF82 invasiveness, intracellular survival and cell–DNA damages.

scholarly journals A Tale of Ice and Fire: The Dual Role for 17β-Estradiol in Balancing DNA Damage and Genome Integrity

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1583
Author(s):  
Sara Pescatori ◽  
Francesco Berardinelli ◽  
Jacopo Albanesi ◽  
Paolo Ascenzi ◽  
Maria Marino ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cellular Transformation ◽  
Genome Integrity ◽  
Physiological Effects ◽  
Dna Damages ◽  
Cellular Effects ◽  
Damage Response ◽  
17Β Estradiol ◽  
Cellular Pathways ◽  
Definition Of

17β-estradiol (E2) regulates human physiology both in females and in males. At the same time, E2 acts as a genotoxic substance as it could induce DNA damages, causing the initiation of cellular transformation. Indeed, increased E2 plasma levels are a risk factor for the development of several types of cancers including breast cancer. This paradoxical identity of E2 undermines the foundations of the physiological definition of “hormone” as E2 works both as a homeostatic regulator of body functions and as a genotoxic compound. Here, (i) the molecular circuitries underlying this double face of E2 are reviewed, and (ii) a possible framework to reconcile the intrinsic discrepancies of the E2 function is reported. Indeed, E2 is a regulator of the DNA damage response, which this hormone exploits to calibrate its genotoxicity with its physiological effects. Accordingly, the genes required to maintain genome integrity belong to the E2-controlled cellular signaling network and are essential for the appearance of the E2-induced cellular effects. This concept requires an “upgrade” to the vision of E2 as a “genotoxic hormone”, which balances physiological and detrimental pathways to guarantee human body homeostasis. Deregulation of this equilibrium between cellular pathways would determine the E2 pathological effects.

scholarly journals NBS1 is regulated by two kind of mechanisms: ATM-dependent complex formation with MRE11 and RAD50, and cell cycle–dependent degradation of protein

2017 ◽  
Vol 58 (4) ◽  
pp. 487-494 ◽  
Author(s):  
Hui Zhou ◽  
Kasumi Kawamura ◽  
Hiromi Yanagihara ◽  
Junya Kobayashi ◽  
Qiu-Mei Zhang-Akiyama
Keyword(s):  
Dna Damage ◽  
Complex Formation ◽  
Genetic Disorder ◽  
Specific Inhibitor ◽  
Nijmegen Breakage Syndrome ◽  
End Joining ◽  
Mrn Complex ◽  
Pre Treatment ◽  
Non Homologous End Joining ◽  
Cycle Dependent

Abstract Nijmegen breakage syndrome (NBS), a condition similar to Ataxia-Telangiectasia (A-T), is a radiation-hypersensitive genetic disorder showing chromosomal instability, radio-resistant DNA synthesis, immunodeficiency, and predisposition to malignances. The product of the responsible gene, NBS1, forms a complex with MRE11 and RAD50 (MRN complex). The MRN complex is necessary for the DNA damage–induced activation of ATM. However, the regulation of MRN complex formation is still unclear. Here, we investigated the regulatory mechanisms of MRN complex formation. We used an immunoprecipitation assay to determine whether levels of the MRN complex were increased by radiation-induced DNA damage and found that the levels of these proteins and their mRNAs did not increase. ATM-dependent phosphorylation of NBS1 contributed to the DNA damage–induced MRN complex formation. However, pre-treatment of cells with an ATM-specific inhibitor did not affect homologous recombination (HR) and non-homologous end-joining (NHEJ) repair. G0 phase cells, decreasing NBS1 and HR activity but not NHEJ, gained HR-related chromatin association of RAD51 by overexpression of NBS1, suggesting that the amount of NBS1 may be important for repressing accidental activation of HR. These evidences suggest that NBS1 is regulated by two kind of mechanisms: complex formation dependent on ATM, and protein degradation mediated by an unknown MG132-resistant pathway. Such regulation of NBS1 may contribute to cellular responses to double-strand breaks.

Effect of Culture Medium and Mannitol Pre-Treatment on Durum Wheat Anther Culture Response

2021 ◽  
Vol 55 (6) ◽  
pp. 590-597
Author(s):  
Th. B. Lazaridou ◽  
A. G. Mavromatis ◽  
I. N. Xynias
Keyword(s):  
Durum Wheat ◽  
Anther Culture ◽  
Culture Medium ◽  
Pre Treatment ◽  
Anther Culture Response

Lowering the inhibition of sugarcane vinasse as a culture medium for oleaginous fungi through oxidative pre‐treatment aiming at the degradation of toxic compounds

2020 ◽  
Vol 95 (11) ◽  
pp. 2943-2950
Author(s):  
Cristiano E Rodrigues Reis ◽  
Ana KF Carvalho ◽  
Heitor BS Bento ◽  
Thiago M Alves ◽  
Heizir F Castro
Keyword(s):  
Culture Medium ◽  
Toxic Compounds ◽  
Oleaginous Fungi ◽  
Pre Treatment ◽  
Sugarcane Vinasse

scholarly journals Exploring the effect of UV-C radiation on earthworm and understanding its genomic integrity in the context of H2AX expression

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Karthikeyan Subbiahanadar Chelladurai ◽  
Jackson Durairaj Selvan Christyraj ◽  
Ananthaselvam Azhagesan ◽  
Vennila Devi Paulraj ◽  
Muralidharan Jothimani ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Primary Response ◽  
Coelomic Fluid ◽  
Dependent Manner ◽  
Perionyx Excavatus ◽  
Dna Damages ◽  
Highly Sensitive ◽  
Evolutionarily Conserved ◽  
Uv C

AbstractMaintaining genomic stability is inevitable for organism survival and it is challenged by mutagenic agents, which include ultraviolet (UV) radiation. Whenever DNA damage occurs, it is sensed by DNA-repairing proteins and thereby performing the DNA-repair mechanism. Specifically, in response to DNA damage, H2AX is a key protein involved in initiating the DNA-repair processes. In this present study, we investigate the effect of UV-C on earthworm, Perionyx excavatus and analyzed the DNA-damage response. Briefly, we expose the worms to different doses of UV-C and find that worms are highly sensitive to UV-C. As a primary response, earthworms produce coelomic fluid followed by autotomy. However, tissue inflammation followed by death is observed when we expose worm to increased doses of UV-C. In particular, UV-C promotes damages in skin layers and on the contrary, it mediates the chloragogen and epithelial outgrowth in intestinal tissues. Furthermore, UV-C promotes DNA damages followed by upregulation of H2AX on dose-dependent manner. Our finding confirms DNA damage caused by UV-C is directly proportional to the expression of H2AX. In short, we conclude that H2AX is present in the invertebrate earthworm, which plays an evolutionarily conserved role in DNA damage event as like that in higher animals.

scholarly journals Xanthohumol, a Prenylated Flavonoid from Hops, Induces DNA Damages in Colorectal Cancer Cells and Sensitizes SW480 Cells to the SN38 Chemotherapeutic Agent

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 932
Author(s):  
Alessandra Scagliarini ◽  
Aline Mathey ◽  
Virginie Aires ◽  
Dominique Delmas
Keyword(s):  
Colorectal Cancer ◽  
Dna Damage ◽  
Anticancer Agents ◽  
Ataxia Telangiectasia Mutated ◽  
Anticancer Compounds ◽  
Dna Damages ◽  
Systematic Screening ◽  
Colorectal Cancer Cells ◽  
Ic50 Values ◽  
First Time

In spite of chemotherapy and systematic screening for people at risk, the mortality rate of colorectal cancer (CRC) remains consistently high, with 600,000 deaths per year. This low success rate in the treatment of CRC results from many failures associated with high resistance and the risk of metastasis. Therefore, in response to these therapeutic failures, new strategies have been under development for several years aimed at increasing the effect of anticancer compounds and/or at reducing their secondary effects on normal cells, thus enabling the host to better withstand chemotherapy. This study highlights that xanthohumol (Xn) concentrations under the IC50 values were able to induce apoptosis and to enhance the DNA-damage response (DDR). We demonstrate for the first time that Xn exerts its anticancer activity in models of colon cancer through activation of the ataxia telangiectasia mutated (ATM) pathway. Subsequently, the ability of Xn to restore DNA damage in CRC cells can sensitize them to anticancer agents such as SN38 (7-ethyl-10-hydroxycamptothecin) used in chemotherapy.

scholarly journals Cellular DNA damage by hydrogen peroxide is attenuated by hypotonicity

1994 ◽  
Vol 299 (1) ◽  
pp. 137-140 ◽  
Author(s):  
E A Martins ◽  
R Meneghini
Keyword(s):  
Dna Damage ◽  
Culture Medium ◽  
Cell Clone ◽  
Chinese Hamster ◽  
Fenton Chemistry ◽  
Structural Modifications ◽  
Hypotonic Stress ◽  
Cellular Dna ◽  
Normal Sensitivity ◽  
Phosphate Buffered Saline

Chinese hamster fibroblasts (line V79) withstand well exposure for 30 min to hypotonic medium, corresponding to 25% physiological phosphate-buffered saline (PBS). Under these conditions, the cells become resistant to two effects of H2O2: DNA damage and inhibition of cell clone formation. The normal sensitivity to the DNA-damaging action of H2O2 is restored if, after exposure to hypotonic PBS, the cells are incubated in isotonic cell-culture medium. However, restoration of sensitivity is not observed on incubation in isotonic PBS. The normal sensitivity to H2O2 is also restored if one of the following reducing agents is added to hypotonic PBS: ascorbate, NADH and NADPH, in this order of decreasing efficiency. The recovery of sensitivity to H2O2 by ascorbate is completely inhibited by 1,10-phenanthroline, indicating that ascorbate is mediating the reduction of Fe(III). The decrease in the sensitivity to the DNA-damaging action of H2O2 is not a peculiarity of hypotonic PBS, since it appears to be caused by hypo-osmolarity in general: it is also observed in culture medium of 25% the isotonic concentration, and in 0.07 M sucrose. One explanation for this phenomenon is that hypotonic stress leads to a depletion of reducing species, in particular ascorbate. Under these conditions Fe(II) tends to be oxidized to Fe(III) and the Fenton chemistry is mitigated. However, other possibilities are that hypotonicity brings about structural modifications in the chromatin, rendering it less accessible to H2O2, or that it attenuates the Ca(2+)-activation of endonuclease, induced by oxidative stress.

scholarly journals Radioprotective Effects of Quercetin and Ethanolic Extract of Propolis in Gamma-Irradiated Mice

2009 ◽  
Vol 60 (2) ◽  
pp. 129-138 ◽  
Author(s):  
Vesna Benković ◽  
Anica Knežević ◽  
Domagoj Đikić ◽  
Duje Lisičić ◽  
Nada Oršolić ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Leukocyte Count ◽  
Ethanolic Extract ◽  
Total Leukocyte Count ◽  
Alkaline Comet Assay ◽  
Irradiation Therapy ◽  
Pre Treatment ◽  
Gamma Irradiated ◽  
Ethanolic Extract Of Propolis

Radioprotective Effects of Quercetin and Ethanolic Extract of Propolis in Gamma-Irradiated MiceThe aim of this study was to assess radioprotective effects of quercetin and the ethanolic extract of propolis (EEP) in CBA mice exposed to a single radiation dose 4 Gy (60Co). The mice were treated with 100 mg kg-1 quercetin or EEP a day for three consecutive days either before (pre-treatment) or after gamma-irradiation (therapy). Leukocyte count was determined in blood drawn from the tail vein, and DNA damage in leukocytes was assessed using the alkaline comet assay. Genotoxic effects of the test compunds were also evaluated in non-irradiated mice. The levels of radioprotection provided by both test compounds were compared with those established in mice that were given chemical radioprotector S-(2-Aminoethy1)isothiouronium bromide hydrobromide (AET). Mice that received pre-treatment were less sensitive to irradiation. Mice given the post-irradiation therapy showed a slight but not significant increase in total leukocyte count over irradiated negative control. Quercetin showed better protective properties than EEP in both pre-treatment and therapy, and activated a higher number of leukocytes in non-irradiated mice. The alkaline comet assay suggests that both natural compounds, especially when given as pre-treatment, protect against primary leukocyte DNA damage in mice. At tested concentrations, EEP and quercetin were not genotoxic to non-irradiated mice. AET, however, caused a slight but not significant increase in DNA damage. Although the results of this study show the radioprotective potential of the test compounds, further investigation is needed to clarify the underlying protection mechanisms.

Bortezomib Enhances Melphalan Response by Altering Fanconi Anemia (FA)/BRCA Pathway Expression and Function.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 840-840 ◽  
Author(s):  
Danielle N. Yarde ◽  
Lori A. Hazlehurst ◽  
Vasco A. Oliveira ◽  
Qing Chen ◽  
William S. Dalton
Keyword(s):  
Gene Expression ◽  
Dna Damage ◽  
Dna Repair ◽  
Low Dose ◽  
Dna Damage Repair ◽  
Myeloma Cell ◽  
Myeloma Cells ◽  
Multiple Myeloma Cell ◽  
Damage Repair ◽  
Pre Treatment

Abstract The FA/BRCA pathway is involved in DNA damage repair and its importance in oncogenesis has only recently been implicated. Briefly, 8 FA/BRCA pathway family members facilitate the monoubiquitination of FANCD2. Upon monoubiquitination, FANCD2 translocates to the DNA repair foci where it interacts with other proteins to initiate DNA repair. Previously, we reported that the FA/BRCA pathway is upregulated in multiple myeloma cell lines selected for resistance to melphalan (Chen, et al, Blood 2005). Further, reducing FANCF in the melphalan resistant 8226/LR5 myeloma cell line partially reversed resistance, whereas overexpressing FANCF in the drug sensitive 8226/S myeloma line conferred resistance to melphalan. Others have reported, and we have also verified, that bortezomib enhances melphalan response in myeloma cells; however, the mechanism of enhanced melphalan activity in combination with bortezomib has not been reported. Based on our observation that the FA/BRCA pathway confers melphalan resistance, we hypothesized that bortezomib enhances melphalan response by targeting FA/BRCA DNA damage repair pathway genes. To investigate this hypothesis, we first analyzed FA/BRCA gene expression in 8226/S and 8226/LR5 cells treated with bortezomib, using a customized microfluidic card (to detect BRCA1, BRCA2, FANCA, FANCC, FANCD2, FANCE, FANCF, FANCG, FANCL, RAD51 and RAD51C) and q-PCR. Interestingly, we found that low dose (5nM) bortezomib decreased many FA/BRCA pathway genes as early as 2 hours, with maximal decreases seen at 24 hours. Specifically, 1.5- to 2.5-fold decreases in FANCA, FANCC, FANCD2, FANCE and RAD51C were seen 24 hours post bortezomib exposure. Moreover, pre-treatment of myeloma cells with low dose bortezomib followed by melphalan treatment revealed a greater than 2-fold reduction in FANCD2 gene expression levels. We also found that melphalan treatment alone enhanced FANCD2 protein expression and activation (monoubiquitination), whereas the combination treatment of bortezomib followed by melphalan decreased activation and overall expression of FANCD2 protein. Taken together, these results suggest that bortezomib enhances melphalan response in myeloma by targeting the FA/BRCA pathway. Further understanding of the role of the FA/BRCA pathway in determining melphalan response may allow for more customized and effective treatment of myeloma.

Imatinib Increases Cytotoxicity of Melphalan and Their Combination Allows An Efficient Killing of CML Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4254-4254
Author(s):  
Cesarina Giallongo ◽  
Piera La Cava ◽  
Daniele Tibullo ◽  
Nunziatina Parrinello ◽  
Provvidenza Guagliardo ◽  
...  
Keyword(s):  
Dna Damage ◽  
Drug Resistance ◽  
Dna Repair ◽  
Conflicts Of Interest ◽  
Leukemic Cells ◽  
Proliferative Potential ◽  
Cell Accumulation ◽  
M Phase ◽  
Pre Treatment ◽  
Human Leukemic Cells

Abstract Abstract 4254 BCR/ABL-positive cells are relatively resistant to chemotherapy and, in order to evaluate the effect of Imatinib (IM) in reverting drug-resistance, we evaluated on K562 the toxicity of 1 h exposure to cytosine arabinoside (ARA-C) 20 μM, hydroxyurea (HU) 100 μM, and melphalan (MEL) 20 μM, after a pre-treatment of 24 h with 1 μM IM. The doses of the drugs were similar to that achieved in the plasma after standard chemoterapeutic treatment. Cell viability was evaluated by ATP-lite at 24, 48 and 72 hs from beginning of drug-free condition. The combinations of IM plus MEL induced the highest cytotoxicity (P<0,001 at 24, 48 and 72 hs vs MEL alone) indicating that pre-treatment with IM increased K562 exposition to the genotoxic damage of MEL. We next analyzed effects on cell cycle and DNA damage by alkaline comet assay induced by this drug combination and we observed that DNA damage peaked at 48 h with IM/MEL combination. In addition, flow cytometry analysis showed that IM/MEL combination reduced the cell accumulation in G2/M phase induced by MEL (P<0.001 vs MEL), thus reducing the ability to DNA repair and recovery. These data indicate that inhibition of BCR/ABL activity by IM increased cell cytotoxicity of MEL by reducing the effectiveness of the DNA-repair pathways and decreasing the time for DNA repair at the G2/M checkpoint.. To ascertain that these results were linked to BCR/ABL inhibition, TonB.210, a cell line where the BCR-ABL expression is inducible by doxycycline (DOX), were treated in the same conditions. Only TonB.210 cultured with DOX were insensitive to MEL while IM/MEL combination reverted these drug resistance (P<0,001). In the final step we studied the sequential association IM/MEL on the proliferative potential of myeloid progenitors of 6 CML patients at diagnosis. IM/MEL combination increased the reduction of the overall number of colonies in comparison to IM alone (P<0.05 vs IM). In addition, the analysis on CFU-GM and BFU-E colonies by qRT-PCR demonstrated that the IM/MEL combination led to the highest reduction in the number of BCR/ABL positive colonies (P<0.01 vs IM). Therefore, our data indicate that the pre-inhibition of BCR/ABL activity by IM increases the toxicity of MEL and allows an efficient killing of human leukemic cells, thus suggesting new therapeutic combinations for CML patients Disclosures: No relevant conflicts of interest to declare.

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