G-quadruplex binding properties of a potent PARP-1 inhibitor derived from 7-azaindole-1-carboxamide

oly ADP-ribose polymerases (PARP) are key proteins involved in DNA repair, maintenance as well as regulation of programmed cell death. For this reason they are important therapeutic targets for cancer treatment. Recent studies have revealed a close interplay between PARP1 recruitment and G-quadruplex stabilization, showing that PARP enzymes are activated upon treatment with a G4 ligand. In this work the DNA binding properties of a PARP-1 inhibitor derived from 7-azaindole-1-carboxamide, (2-[6-(4-pyrrolidin-1-ylmethyl-phenyl)-pyrrolo[2,3-b]pyridin-1-yl]-acetamide, compound 1) with model duplex and quadruplex DNA oligomers were studied by NMR, CD, fluorescence and molecular modelling. We provide evidence that compound 1 is a strong G-quadruplex binder. In addition we provide molecular details of the interaction of compound 1 with two model G-quadruplex structures: the single repeat of human telomeres, d(TTAGGGT)4, and the c-MYC promoter Pu22 sequence. The formation of defined and strong complexes with G-quadruplex models suggests a dual G4 stabilization/PARP inhibition mechanism of action for compound 1 and provides the molecular bases of its therapeutic potential

Stabilization of c-KIT G-Quadruplex DNA structures by the RNA polymerase I inhibitors BMH-21 and BA-41

The stabilization of G-quadruplex DNA structures by small molecules with affinity to oncogene promoters has emerged as a promising anticancer strategy, due to a potential role in gene expression regulation. We explored the ability of BMH-21 (1) and its analogue BA-41 (2) to bind the G-quadruplex structure present in the c-KIT promoter by biophysical methods and molecular modeling. We provide evidence that both compounds interact with the c-KIT 21-mer sequence. The stable monomeric intramolecular parallel G-quadruplex obtained by the mutation of positions 12 and 21 allowed the precise determination of the binding mode by NMR and molecular dynamics studies. Both compounds form a complex characterized by one ligand molecule positioned over the tetrad at the 30-end, stabilized by an extensive network of pi-pi interactions. The binding constants (Kb) obtained with fluorescence are similar for both complexes (around 10^6 M-1). Compound BA-41 (2) showed significant antiproliferative activity against a human lymphoma cell line, SU-DHL4, known to express substantial levels of c-KIT. However, the partial inhibition of c-KIT expression by Western blot analysis suggested that the interaction of compound 2 with the c-KIT promoter is not the primary event and that multiple e ects provide a contribution as determinants of biological activity

Alkalizing Reactions Streamline Cellular Metabolism in Acidogenic Microorganisms

An understanding of the integrated relationships among the principal cellular functions that govern the bioenergetic reactions of an organism is necessary to determine how cells remain viable and optimise their fitness in the environment. Urease is a complex enzyme that catalyzes the hydrolysis of urea to ammonia and carbonic acid. While the induction of urease activity by several microorganisms has been predominantly considered a stress-response that is initiated to generate a nitrogen source in response to a low environmental pH, here we demonstrate a new role of urease in the optimisation of cellular bioenergetics. We show that urea hydrolysis increases the catabolic efficiency of Streptococcus thermophilus, a lactic acid bacterium that is widely used in the industrial manufacture of dairy products. By modulating the intracellular pH and thereby increasing the activity of β-galactosidase, glycolytic enzymes and lactate dehydrogenase, urease increases the overall change in enthalpy generated by the bioenergetic reactions. A cooperative altruistic behaviour of urease-positive microorganisms on the urease-negative microorganisms within the same environment was also observed. The physiological role of a single enzymatic activity demonstrates a novel and unexpected view of the non-transcriptional regulatory mechanisms that govern the bioenergetics of a bacterial cell, highlighting a new role for cytosol-alkalizing biochemical pathways in acidogenic microorganisms

Libro "In cucina con l'erisimo"

Libro di ricette con l'erba dei cantanti, prodotto all'interno del progetto Erisimo a Milan

A new index of transparency: Evidence for the Italian municipalities

This paper contributes to the literature on transparency measurement defining and constructing a new synthetic indicator (Italian Transparency Index - ITI) through the adoption of a methodology suitable for the treatment of system of ordinal indicators, the partially ordered set (poset). With respect to the existing measures of transparency proposed in the literature, the ITI has the advantage to identify precisely all the different and specific transparency profiles. This methodology is applied to the fulfillment of the Italian regulation on transparency by the Municipalities focusing on two dimensions of the public action, i.e. integrity and efficiency and adopts a two steps procedure. Firstly, we construct a synthetic index for each of the two above-mentioned transparency dimensions. Secondly, we define a synthetic measure of transparency starting from the two previous indicators. Thus, we focus on the synthesis of basic indicators, in order to aggregate their values for each statistical units of a sample of Italian Municipalities. The ITI can be a useful tool for policymakers to monitor the state of transparency within and across the administrative units and to design more informed and targeted policies with likely positive implications in terms of effectiveness

Pedicled posteromedial thigh (PMT) flap: A new alternative for groin defect reconstruction

The posterior medial thigh is mainly vascularized by the profunda femoris artery (PFA), which nourishes the adductor magnus muscle and overlying skin, to supply a number of perforators that can potentially be used as pedicles for local perforator flaps. Here we present two cases utilizing the pedicled posteromedial thigh flap (PMT) to reconstruct the groin defects. Two patients underwent resection for metastatic malignant melanoma resulting in large defects of the groin with exposure of major inguinal vessels; the dimensions of the skin defects were 15 cm × 5 cm and 16 cm × 6 cm, two ipsilateral pedicled PMT flaps were designed to cover the defects. The pedicled PMT flaps were based on perforators arising from the PFA and were transposed through a submuscular tunnel into the defect. The postoperative course was uneventful and the wounds were reconstructed successfully. The pedicled PMT flap may be an option for reconstruction of groin defects and could be incorporated into the armamentarium of the reconstructive microsurgeon. © 2015 Wiley Periodicals, Inc. Microsurgery, 2015

Total synthesis of leopolic acid A, a natural 2,3-pyrrolidinedione with antimicrobial activity

The first total synthesis of leopolic acid A, a fungal metabolite with a rare 2,3-pyrrolidinedione nucleus linked to an ureido dipeptide, was designed and carried out. Crucial steps for the strategy include a Dieckmann cyclization to obtain the 2,3-pyrrolidinedione ring and a Wittig olefination to install the polymethylene chain. An oxazolidinone-containing leopolic acid A analogue was also synthesized. The antibacterial activity showed by both compounds suggests that they could be considered as promising candidates for future developments