Phytochemicals in cancer prevention: modulating epigenetic alterations of DNA methylation

Phytochemistry Reviews - Cancer can take many years to develop from initiation to progression. The long period of development might represent an opportunity to use multi-functional, multi-targeted...     

A bootstrap-aggregated hybrid semi-parametric modeling framework for bioprocess development

Bioprocess and Biosystems Engineering - Hybrid semi-parametric modeling, combining mechanistic and machine-learning methods, has proven to be a powerful method for process development. This paper...     

Oncogenic Regulation of Extracellular Vesicle Proteome and Heterogeneity

Mutational and epigenetic driver events profoundly alter intercellular communication pathways in cancer. This effect includes deregulated release, molecular composition, and biological activity of extracellular vesicles (EVs), membranous cellular fragments ranging from a few microns to less than 100 nm in diameter and filled with bioactive molecular cargo (proteins, lipids, and nucleic acids). While EVs are usually classified on the basis of their physical properties and biogenetic mechanisms, recent analyses of their proteome suggest a larger than expected molecular diversity, a notion that is also supported by multicolour nano‐flow cytometry and other emerging technology platforms designed to analyze single EVs. Both protein composition and EV diversity are markedly altered by oncogenic transformation, epithelial to mesenchymal transition, and differentiation of cancer stem cells. Interestingly, only a subset of EVs released from mutant cells may carry oncogenic proteins (e.g., EGFRvIII), hence, these EVs are often referred to as “oncosomes”. Indeed, oncogenic transformation alters the repertoire of EV‐associated proteins, increases the presence of pro‐invasive cargo, and alters the composition of distinct EV populations. Molecular profiling of single EVs may reveal a more intricate effect of transforming events on the architecture of EV populations in cancer and shed new light on their biological role and diagnostic utility.     

Proteoglycan fragmentation and respiratory mechanics in mechanically ventilated healthy rats.

This research investigated whether stretching of lung tissue due to increased positive alveolar pressure swings during mechanical ventilation (MV) at various tidal volumes (V(T)) might affect the composition and/or structure of the glycosaminoglycan (GAG) components of pulmonary extracellular proteoglycans. Experiments were performed in 30 healthy rats: 1) anesthetized and immediately killed (controls, C-0); 2) anesthetized and spontaneously breathing for 4 h (C-4h); and 3) anesthetized, paralyzed, and mechanically ventilated for 4 h with air at 0-cmH(2)O end-expiratory pressure and V(T) of 8 ml/kg (MV-1), 16 ml/kg (MV-2), 24 ml/kg (MV-3), or 32 ml/kg (MV-4), adjusting respiratory rates at a minute ventilation of 270 ml/min. Compared with C-0 and C-4h, a significant reduction of dynamic and static compliance of the respiratory system and of the lung was observed only in MV-4, while extravascular lung water significantly increased in MV-3 and MV-4, but not in MV-1 and MV-2. However, even in MV-1, MV induced a significant fragmentation of pulmonary GAGs. Extraction of covalently bound GAGs and wash out of loosely bound or fragmented GAGs progressively increased with increasing V(T) and was associated with increased expression of local (matrix metalloproteinase-2) and systemic (matrix metalloproteinase-9) activated metalloproteases. We conclude that 1) MV, even at "physiological" low V(T), severely affects the pulmonary extracellular architecture, exposing the lung parenchyma to development of ventilator-induced lung injury; and 2) respiratory mechanics is not a reliable clinical tool for early detection of lung injury.     

Morphological changes induced in erythrocyte by amyloid beta peptide and glucose depletion: A combined atomic force microscopy and biochemical study

Circulating red blood cells (RBCs) undergo aging, a fundamental physiological phenomenon that regulates their turnover. We show that treatment with beta amyloid peptide 1–42 (Aβ) accelerates the occurrence of morphological and biochemical aging markers in human RBCs and influences the cell metabolism leading to intracellular ATP depletion. The morphological pattern has been monitored using Atomic Force Microscopy (AFM) imaging and measuring the RBCs' plasma membrane roughness employed as a morphological parameter capable to provide information on the structure and integrity of the membrane-skeleton. Results evidence that Aβ boosts the development of crenatures and proto-spicules simultaneously to acceleration in the weakening of the cell-cytoskeleton contacts and to the induction of peculiar nanoscale features on the cell membrane. Incubation in the presence of glucose can remove all but the latter Aβ-induced effects.Biochemical data demonstrate that contemporaneously to morphological and structural alterations, Aβ and glucose depletion trigger a complex signaling pathway involving caspase 3, protein kinase C (PKC) and nitric oxide derived metabolites.As a whole, the collected data revealed that, the damaging path induced by Aβ in RBC provide a sequence of morphological and functional intermediates following one another along RBC life span, including: (i) an acceleration in the development of shape alteration typically observed along the RBC's aging; (ii) the development of characteristic membrane features on the plasma membrane and (iii) triggering a complex signaling pathway involving caspase 3, PKC and nitric oxide derived metabolites.     

In vitro exposure of human lymphocytes to 900 MHz CW and GSM modulated radiofrequency: studies of proliferation, apoptosis and mitochondrial membrane potential

The aim of this study was to investigate the nonthermal effects of radiofrequency (RF) fields on human immune cells exposed to a Global System for Mobile Communication (GSM) signal generated by a commercial cellular phone and by a sinusoidal non-modulated signal. To assess whether mobile phone RF-field exposure affects human immune cell functions, peripheral blood mononuclear cells (PBMCs) from healthy donors were exposed in vitro to a 900 MHz GSM or continuous-wave (CW) RF field 1 h/day for 3 days in a transverse electromagnetic mode (TEM) cell system (70-76 mW/kg average specific absorption rate, SAR). The cells were cultured for 48 or 72 h, and the following end points were studied: (1) mitogen-induced proliferation; (2) cell cycle progression; (3) spontaneous and 2-deoxy-D-ribose (dRib)-induced apoptosis; (4) mitochondrial membrane potential modifications during spontaneous and dRib-induced-apoptosis. Data obtained from cells exposed to a GSM-modulated RF field showed a slight decrease in cell proliferation when PBMCs were stimulated with the lowest mitogen concentration and a slight increase in the number of cells with altered distribution of phosphatidylserine across the membrane. On the other hand, cell cycle phases, mitochondrial membrane potential and susceptibility to apoptosis were found to be unaffected by the RF field. When cells were exposed to a CW RF field, no significant modifications were observed in comparison with sham-exposed cells for all the end points investigated.     

Involvement of peptidorhamnomannan in the interaction of Pseudallescheria boydii and HEp2 cells

Pseudallescheria boydii is an emerging fungal pathogen that has a worldwide distribution. Virulence mechanisms of P. boydii are largely unknown. We studied the interaction between P. boydii and HEp2 cells and demonstrated that conidia of P. boydii attached to, and were ingested by, HEp2 cells in a time-dependent process. After 2 h of interaction, the conidia produced a germ-tube like projection, which was able to penetrate the epithelial cell membrane. Recently, our group characterized a peptidorhamnomannan (PRM) antigen on the cell surface of P. boydii. In order to better understand the role played by this surface glycoconjugate during cell adhesion and endocytosis, inhibition assays were performed using intact PRM and anti-PRM polyclonal antibody. When HEp2 cells were pre-treated with whole PRM molecule, the adhesion and endocytic indices were, respectively, 50% and 60% lower than in non-treated epithelial cells. Moreover, when the conidial cells were pre-incubated with anti-PRM antibodies, the adherence and endocytosis processes were inhibited in a dose-dependent manner. As PRM influenced the conidia P. boydii-HEp2 cell interaction, we also performed inhibition assays in order to observe which PRM moieties could be involved in this process. Treatment of PRM with proteinase K promoted a slight inhibition of adhesion. However, the de-O-glycosylated PRM molecule as well as the monosaccharide mannose was able to efficiently inhibit the adhesion and endocytic processes. In addition, our results indicate for the first time that P. boydii PRM binds to a polypeptide of 25 kDa on the HEp2 cell surface.     

Palynological dating of the Alturaia Arkose (Balagne, northern Corsica): geological implications

In Alpine Corsica, the Balagne Nappe displays the best-developed sedimentary succession associated with an ophiolite sequence. This sedimentary succession includes the Alturaia Arkose, whose age is still unknown. Several shale horizons cropping out in the Cima di Alturaia area were studied for palynological analyses. In this paper, a new palaeontological find in the Alturaia Arkose is reported and the related geological implications are discussed. The collected data indicate the occurrence of a palynological assemblage of Late Barremian to Middle Aptian age. The Alturaia Arkose can be regarded as a clastic deposit of Late Barremian–Middle Aptian age derived from rocks cropping out in Hercynian Corsica. To cite this article: M. Marroni et al., C. R. Palevol 3 (2004).

Résumé

Datation palynologique de l’arkose de l’Alturaia (Balagne, Corse septentrionale) : conséquences géologiques. En Corse alpine, la nappe de Balagne montre la meilleure succession sédimentaire associée à une séquence ophiolitique. Cette succession inclut l’arkose de l’Alturaia, dont l’âge est encore inconnu. Plusieurs horizons de shales ont été étudiés en vue d’analyses palynologiques, dans la zone de la Cima di l’Alturaia. Nous y indiquons une découverte paléontologique, et nous en discutons les implications géologiques. Les données nouvelles montrent la présence d’un assemblage palynologique d’âge Barrémien supérieur–Aptien moyen. L’arkose de l’Alturaia peut ainsi être considérée comme un dépôt détritique de cet âge, alimenté par les roches affleurant dans la Corse hercynienne. Pour citer cet article : M. Marroni et al., C. R. Palevol 3 (2004).     

Missense,nonsense, and neutral mutations define juxtaposed regulatory elements of splicing in cystic fibrosis transmembrane regulator exon 9

Exonic sequence variations may induce exon inclusion or exclusion from the mature mRNA by disrupting exonic regulatory elements and/or by affecting a nuclear reading frame scanning mechanism. We have carried out a systematic study of the effect on cystic fibrosis transmembrane regulator exon 9 splicing of natural and site-directed sequence mutations. We have observed that changes in the splicing pattern were not related to the creation of premature termination codons, a fact that indicates the lack of a significant nuclear check of the reading frame in this system. In addition, the splice pattern could not be predicted by available Ser/Arg protein matrices score analysis. An extensive site-directed mutagenesis of the 3' portion of the exon has identified two juxtaposed splicing enhancer and silencer elements. The study of double mutants at these regulatory elements showed a complex regulatory activity. For example, one natural mutation (146C) enhances exon inclusion and overrides all of the downstream silencing mutations except for a C to G transversion (155G). This unusual effect is explained by the creation of a specific binding site for the inhibitory splicing factor hnRNPH. In fact, on the double mutant 146C-155G, the silencing effect is dominant. These results indicate a strict dependence between the two juxtaposed enhancer and silencer sequences and show that many point mutations in these elements cause changes in splicing efficiency by different mechanisms.