Mechanistic Insights on the Inhibition of C5 DNA Methyltransferases by Zebularine

In mammals DNA methylation occurs at position 5 of cytosine in a CpG context and regulates gene expression. It plays an important role in diseases and inhibitors of DNA methyltransferases (DNMTs)—the enzymes responsible for DNA methylation—are used in clinics for cancer therapy. The most potent inhibitors are 5-azacytidine and 5-azadeoxycytidine. Zebularine (1-(β-D-ribofuranosyl)-2(1H)- pyrimidinone) is another cytidine analog described as a potent inhibitor that acts by forming a covalent complex with DNMT when incorporated into DNA. Here we bring additional experiments to explain its mechanism of action. First, we observe an increase in the DNA binding when zebularine is incorporated into the DNA, compared to deoxycytidine and 5-fluorodeoxycytidine, together with a strong decrease in the dissociation rate. Second, we show by denaturing gel analysis that the intermediate covalent complex between the enzyme and the DNA is reversible, differing thus from 5-fluorodeoxycytidine. Third, no methylation reaction occurs when zebularine is present in the DNA. We confirm that zebularine exerts its demethylation activity by stabilizing the binding of DNMTs to DNA, hindering the methylation and decreasing the dissociation, thereby trapping the enzyme and preventing turnover even at other sites

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Homéopathie vétérinaire (principes, application de la loi de la similitude chez le cheval et place des laboratoires homéopathiques et du pharmacien)

La première partie de ce sujet présente l'homéopathie : son histoire, ses principes et introduira son application en médecine vétérinaire. Dans un second temps, est évoquée l'application de la loi de similitude, méthode nécessitant d'envisager le malade dans sa totalité symptomatologique (mentale, émotionnelle et physique) pour conduire à une prescription individualisée, correspondant aux particularités réactionnelles propres à chaque patient. De nombreux cas cliniques (26) appliqués au cheval issus de la pratique de vétérinaires renommés vont illustrer les aptitudes et les évolutions propres à cette médecine. Enfin, est abordé le rôle des laboratoires homéopathiques et du pharmacien, interfaces indispensables entre le prescripteur et son malade (ou le propriétaire de l'animal en médecine vétérinaire).AMIENS-BU Santé (800212102) / SudocSudocFranceF

Pneumopathies associées au sirolimus (à propos de 24 cas en transplantation rénale)

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Projet agroécologique RIVAGE: (Émission Kamannyòk sur Guadeloupe Première le 2/06/2018)

dans le cadre du Joli mois de l’EuropeComment réduire l’impact de l’agriculture sur l’environnement en limitant la pollution de la ressource en eau par les pesticides ? C’est le sens du projet agroécologique RIVAGE, qui regroupe quatre organismes : l’INRA, le CIRAD, le BRGM et l’Université des Antilles. Après une première phase de diagnostic de la pollution des rivières et des nappes phréatiques par les pesticides, la deuxième phase consiste à réfléchir à de nouvelles pratiques, afin de protéger la ressource en eau (reportage version web). Intervenants : - Marc Dorel, agronome au CIRAD ; - Patrick Andrieux, hydropédologue à l’INRA ; - Diane Rakotomanga, agronome au CIRAD ; - Lise Ponchant, hydrologue à l’INRA ; - Laure Ducreux, hydrogéologue régionale (BRGM

Malakoplakia as a cause of severe hypercalcemia through ectopic 25-hydroxyvitamin D3 1-alpha-hydroxylase expression

International audienc

DNA Core Ionization and Cell Inactivation

International audienceBoissie` re, A., Champion, C., Touati, A., Herve ́ du Penhoat, M. A., Sabatier, L., Chatterjee, A. and Chetioui, A. DNA Core Ionization and Cell Inactivation. Radiat. Res. 167, 493–500 (2007). Whether inner-shell ionizations of DNA atoms, called core ionizations, are critical events for cell inactivation by ionizing radiations such as 100 keV electrons an

Absolute frequency of NRY haplogroups in the Antemoro.

<p>The maximum parsimony phylogeny relating the NRY haplogroups is label with markers that define them.</p

Median-Joining network computed from Y-STR minimal haplotypes (DYS19, DYS389i, DYS389ii, DYS390, DYS391, DYS392, DYS393) in the Antemoro and populations from various geographic regions belonging to haplogroup T.

<p>Circles are haplotypes. Size of these circle are proportional to haplotype frequency and branch lengths are proportional to number of differences between haplotypes.</p