TP53 transcription factor for the NEDD9/HEF1/Cas-L gene: potential targets in Non-Small Cell Lung Cancer treatment

International audienceLung cancer is a serious public health problem. Although there has been significant progress in chemotherapy, non-small cell lung cancer is still resistant to current treatments, primarily because of the slow rate of cell development. It is thus important to find new molecules directed against targets other than proliferation agents. Considering the high proportion of mutant proteins in tumor cells, and the high rate of mutation of the TP53 gene in all cancers, and in NSCLC in particular, this gene is a perfect target. Certain new molecules have been shown to restore the activity of mutated p53 protein, for example PRIMA-1, which reactivates the His273 mutant p53. In a previous study, we presented triazine A190, a molecule with a cytostatic activity that blocks cells in the G1 phase and induces apoptosis. Here, we show that A190 not only restores mutant p53 activity, but also induces an overexpression of the NEDD9 gene, leading to apoptotic death. These findings might offer hope for the development of new targeted therapies, specific to tumor cells, which spare healthy cell

Triad pattern algorithm for predicting strong promoter candidates in bacterial genomes

Abstract Background Bacterial promoters, which increase the efficiency of gene expression, differ from other promoters by several characteristics. This difference, not yet widely exploited in bioinformatics, looks promising for the development of relevant computational tools to search for strong promoters in bacterial genomes. Results We describe a new triad pattern algorithm that predicts strong promoter candidates in annotated bacterial genomes by matching specific patterns for the group I σ70 factors of Escherichia coli RNA polymerase. It detects promoter-specific motifs by consecutively matching three patterns, consisting of an UP-element, required for interaction with the α subunit, and then optimally-separated patterns of -35 and -10 boxes, required for interaction with the σ70 subunit of RNA polymerase. Analysis of 43 bacterial genomes revealed that the frequency of candidate sequences depends on the A+T content of the DNA under examination. The accuracy of in silico prediction was experimentally validated for the genome of a hyperthermophilic bacterium, Thermotoga maritima, by applying a cell-free expression assay using the predicted strong promoters. In this organism, the strong promoters govern genes for translation, energy metabolism, transport, cell movement, and other as-yet unidentified functions. Conclusion The triad pattern algorithm developed for predicting strong bacterial promoters is well suited for analyzing bacterial genomes with an A+T content of less than 62%. This computational tool opens new prospects for investigating global gene expression, and individual strong promoters in bacteria of medical and/or economic significance.</p

Reactive Chemicals and Electrophilic Stress in Cancer: A Minireview

Exogenous reactive chemicals can impair cellular homeostasis and are often associated with the development of cancer. Significant progress has been achieved by studying the macromolecular interactions of chemicals that possess various electron-withdrawing groups and the elucidation of the protective responses of cells to chemical interventions. However, the formation of electrophilic species inside the cell and the relationship between oxydative and electrophilic stress remain largely unclear. Derivatives of nitro-benzoxadiazole (also referred as nitro-benzofurazan) are potent producers of hydrogen peroxide and have been used as a model to study the generation of reactive species in cancer cells. This survey highlights the pivotal role of Cu/Zn superoxide dismutase 1 (SOD1) in the production of reactive oxygen and electrophilic species in cells exposed to cell-permeable chemicals. Lipophilic electrophiles rapidly bind to SOD1 and induce stable and functionally active dimers, which produce excess hydrogen peroxide leading to aberrant cell signalling. Moreover, reactive oxygen species and reactive electrophilic species, simultaneously generated by redox reactions, behave as independent entities that attack a variety of proteins. It is postulated that the binding of the electrophilic moiety to multiple proteins leading to impairing different cellular functions may explain unpredictable side effects in patients undergoing chemotherapy with reactive oxygen species (ROS)-inducing drugs. The identification of proteins susceptible to electrophiles at early steps of oxidative and electrophilic stress is a promising way to offer rational strategies for dealing with stress-related malignant tumors

DEVELOPPEMENT D'UNE APPROCHE RAPIDE ET UNIVERSELLE POUR LA PREPARATION DES PUCES A PARTIR DE PROTEINES SYNTHETISEES IN VITRO EN VUE DE L'ETUDE DES INTERACTIONS INTERMOLECULAIRES

NANTES-BU Sciences (441092104) / SudocSudocFranceF

Étude des voies de signalisation MAPK et PI3K/Akt dans deux modèles animaux de la dystrophie musculaire de Duchenne (la souris mdx et le chien GRMD)

Bien que l origine de la dystrophie musculaire de Duchenne soit connue, des mutations dans le gène DMD aboutissant à l absence de dystrophine, les mécanismes globaux définissant la pathogénie ne sont toujours pas élucidés. L implication d un dérèglement des voies de signalisation a été suggéré et nous souhaitions utiliser la technologie des puces à anticorps pour obtenir une vision globale des modulations affectant les voies MAPK et PI3K/Akt dans le muscle dystrophique. Après une première étude chez la souris mdx, les travaux ont été poursuivis sur le modèle du chien GRMD qui, de part sa physio-pathologie extrêmement proche de celle de l homme, nous paraissait plus adapté. La comparaison du profil de phosphorylation de 19 kinases dans les muscles sain et GRMD révèle que Akt1, ses cibles directes et indirectes GSK3b et p70S6K, ainsi que les MAPK ERK1/2, p38d et p38g présentent toutes une phosphorylation réduite dans le muscle GRMD. Les tests d activité enzymatique montrent que le défaut de phosphorylation des kinases de la voie PI3K/Akt détecté est associé à une activité réduite pour Akt et augmentée pour GSK3b (corrélé par une sur-expression de la kinase). Des expériences de western blot et des tests enzymatiques révèlent une augmentation de l expression et de l activité de la phosphatase PTEN, alors que les expériences de double marquage immunologique montrent la présence dans le muscle GRMD de fibres PTEN/GSK3b-positives et ce, à plusieurs stades. L ensemble de ces travaux suggère que l activation de PTEN dans le muscle dystrophique pourrait empêcher l hypertrophie compensatoire régulée par la voie PI3K/Akt et aggraver les conséquences de l absence de dystrophineAlthough the origin of Duchenne muscular dystrophy is known, mutations in the DMD gene leading to the absence of dystrophin, the global mechanisms defining the pathogenesis are not yet understood. The implication of signaling pathway deregulation has been suggested and we wanted to take advantage of the antibody array technology to obtain a global overview of the modulations affecting the MAPK and PI3K/Akt pathways in dystrophic muscle. After a first study in the mdx mouse model, the work has been carried out in the GRMD dog that, thanks to its pathophysiology extremely close to that of human patients, appeared more pertinent to this study. The comparison of the phosphorylation profile of 19 different kinases between healthy and GRMD skeletal muscles reveale that Akt1, its direct and indirect targets GSK3b and p70S6K, along with the MAPK ERK1/2, p38d and p38g, all exhibit a reduced phosphorylation level in GRMD muscle. Enzymatic assays show that the phosphorylation defect of the PI3K/Akt pathway kinases detected in GRMD muscle is associated with decreased Akt and increased GSK3b activity (corroborated by an over-expression of the kinase). Western immunoblot experiments and enzymatic assays reveal increased expression and activity of the PTEN phosphatase, whereas immunohistochemcal double staining experiments show the presence in GRMD muscle sections of PTEN/GSK3b-positive fibers, and this at different stages of the disease. Taken together, these results suggest that PTEN activation in dystrophic muscle could prevent the compensatory hypertrophy response that is regulated by the PI3K/Akt pathway, and exacerbate the consequences of the absence of dystrophinNANTES-BU Sciences (441092104) / SudocSudocFranceF

La sous-unité alpha de l'ARN polymérase de Mycobacterium tuberculosis (dimérisation et ciblage de l'interface protéine-protéine pour le développement d'inhibiteurs de la transcription)

Nous avons étudié la sous-unité a de l'ARN polymérase de M. tuberculosis (aMt) en postulant que l'interface protéine-protéine, impliquée dans sa dimérisation, représente une cible attractive pour la création de nouveaux agents antibactériens. La protéine aMt engendre la formation d'un homodimère qui assure l'assemblage du complexe multiprotéique en s'associant avec les autres sous-unités de l'ARN polymérase d'Escherichia coli. Cependant, la sous-unité aMt ne peut pas former d'hétérodimère avec celle d'E. coli. La modélisation du domaine de dimérisation a permis de prédire la séquence d'inhibiteurs peptidiques ciblant l'interface protéique de l'homodimère aMt. L'effet de ces inhibiteurs a été confirmé in vitro par les méthodes conventionnelles. Une approche, basée sur l'avantage d'une puce à protéine auto-assemblée à partir des monomères aMt synthétisées par un système acellulaire, a été développée pour le criblage de petites molécules, inhibiteurs potentiels de la transcription.We studied the M. tuberculosis RNA polymerase a subunit (aMt), postulating that the protein-protein interface implied in its dimerization is an attractive target for the creation of new antibacterial agents. The aMt monomers form a homodimer, which ensures the assembly of the multiproteic complex while binding to other Escherichia coli RNA polymerase subunits. However, the aMt protein cannot form a heterodimer with a subunit of E. coli. Modelling of the aM.t dimerization domain allowed predicting peptide inhibitor sequences targeting the interface of the homodimer. Effect of these inhibitors was confirmed in vitro by conventional methods. An approach, based on the advantage of protein microarrays self-assembled from the cell-free synthesized aMt monomers, was developed for the screening of small molecules, potential inhibitors of transcription.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Targeted Strategies for Degradation of Key Transmembrane Proteins in Cancer

Targeted protein degradation is an attractive technology for cancer treatment due to its ability to overcome the unpredictability of the small molecule inhibitors that cause resistance mutations. In recent years, various targeted protein degradation strategies have been developed based on the ubiquitin–proteasome system in the cytoplasm or the autophagy–lysosomal system during endocytosis. In this review, we describe and compare technologies for the targeted inhibition and targeted degradation of the epidermal growth factor receptor (EGFR), one of the major proteins responsible for the onset and progression of many types of cancer. In addition, we develop an alternative strategy, called alloAUTO, based on the binding of new heterocyclic compounds to an allosteric site located in close proximity to the EGFR catalytic site. These compounds cause the targeted degradation of the transmembrane receptor, simultaneously activating both systems of protein degradation in cells. Damage to the EGFR signaling pathways promotes the inactivation of Bim sensor protein phosphorylation, which leads to the disintegration of the cytoskeleton, followed by the detachment of cancer cells from the extracellular matrix, and, ultimately, to cancer cell death. This hallmark of targeted cancer cell death suggests an advantage over other targeted protein degradation strategies, namely, the fewer cancer cells that survive mean fewer chemotherapy-resistant mutants appear

Triad pattern algorithm for predicting strong promoter candidates in bacterial genomes-2

Moters; consensus of the UP element is described in [26, 27]; (C) the strong promoters Pand Pwere used as references in this study.<p><b>Copyright information:</b></p><p>Taken from "Triad pattern algorithm for predicting strong promoter candidates in bacterial genomes"</p><p>http://www.biomedcentral.com/1471-2105/9/233</p><p>BMC Bioinformatics 2008;9():233-233.</p><p>Published online 9 May 2008</p><p>PMCID:PMC2412878.</p><p></p