Targeting ligand–receptor interactions for development of cancer therapeutics

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Role of IP₃ receptor in development

IP? receptor is a Ca(2+) release channel localized on the endoplasmic reticulum. IP(3) receptor is composed of three isoforms, which are expressed in various cells and tissues, and play variety of roles throughout development. I here describe the role of IP? receptor from oogenesis, meiotic maturation and fertilization. I also describe the Ca(2+) signaling at meiosis and mitosis, and especially the role in early embryogenesis to determine dorso-ventral axis formation. Loss of function mutation of type 1 IP? receptor in mouse, both by gene targeting and spontaneous mutations shows severe ataxia and other phenotypes. Interestingly, double knockouts of type 1 and type 2 exhibit cardiogenesis arrest and that of type 2 and type 3 results in exocrine secretion deficit. IP?R of Drosophila or Caenorhabditis elegans is single gene and mutation results severe phenotype of behavior. All the data described here show that IP?Rs are essential for life and abnormality of IP(3)Rs results in severe abnormality in its structure and function of organism.     

Low-nutrient induction of abnormal chlamydial development: A novel component of chlamydial pathogenesis?

Abstract The intracellular development of chlamydiae in McCoy cells incubated in Eagle's minimal essential medium lacking all 13 amino acids was examined both by fluorescence and electron microscopy and by infectivity titration. Aberrant development occurred in almost all inclusions of strains of Chlamydia trachomatis and C. psittaci with the production of abnormal forms which differed in size, shape and internal structure from normal reticulate and elementary body forms. Detailed analysis of the response of C. trachomatis L2 strain 434 to graded reductions in amino acid level showed that infectivity was reduced and morphological abnormality increased as amino acid concentrations were lowered from 33 to 0% of amino acids present in minimal essential medium. Reversion of inclusions to normal and reappearance of infectious forms occured on restoration of amino acids and further incubation. It is suggested that aberrant development may account for the presence in vivo of non-cultivable chlamydiae and that such development can arise via tryptophan deprivation mediated by local release of interferon gamma.     

Evolution of “determinants” in sex-determination: A novel hypothesis for the origin of environmental contingencies in avian sex-bias

Sex-determination is commonly categorized as either “genetic” or “environmental”—a classification that obscures the origin of this dichotomy and the evolution of sex-determining factors. The current focus on static outcomes of sex-determination provides little insight into the dynamic developmental processes by which some mechanisms acquire the role of sex determinants. Systems that combine “genetic” pathways of sex-determination (i.e., sex chromosomes) with “environmental” pathways (e.g., epigenetically induced segregation distortion) provide an opportunity to examine the evolutionary relationships between the two classes of processes and, ultimately, illuminate the evolution of sex-determining systems. Taxa with sex chromosomes typically undergo an evolutionary reduction in size of one of the sex chromosomes due to suppressed recombination, resulting in pronounced dimorphism of the sex chromosomes, and setting the stage for emergence of epigenetic compensatory mechanisms regulating meiotic segregation of heteromorphic sex chromosomes. Here we propose that these dispersed and redundant regulatory mechanisms enable environmental contingency in genetic sex-determination in birds and account for frequently documented context-dependence in avian sex-determination. We examine the evolution of directionality in such sex-determination as a result of exposure of epigenetic regulators of meiosis to natural selection and identify a central role of hormones in integrating female reproductive homeostasis, resource allocation to oocytes, and offspring sex. This approach clarifies the evolutionary relationship between sex-specific molecular genetic mechanisms of sex-determination and non-sex-specific epigenetic regulators of meiosis and demonstrates that both can determine sex. Our perspective shows how non-sex-specific mechanisms can acquire sex-determining function and, by establishing the explicit link between physiological integration of oogenesis and sex-determination, opens new avenues to the studies of adaptive sex-bias and sex-specific resource allocation in species with genetic sex-determination.     

The “proletarian disease” on stage. Theatrical anti-tuberculosis propaganda in the early Soviet Union

The present contribution analyses sanitary theatrical performances as a means of anti-tuberculosis propaganda in the early Soviet Union. Starting in the 1920s, sanitary theatrical performances were demonstrated in open-air theatres and clubhouses for workers and farmers. Since 1925, the newly founded Moscow Theatre for Sanitary Culture centrally managed the theatrical hygiene propaganda. It became a role model for other theatres of hygienic enlightenment and numerous sanitary amateur stages. Their anti-tuberculosis repertoire ranged from the so-called “mock trials” where a person or even Koch's bacillus must stand trial for the spreading of tuberculosis, to “living newspapers” which used entertainment elements such as music or acrobatics to provide a mass audience with the hygiene knowledge. The contribution describes in which images, figures and actions knowledge about tuberculosis was presented on stage, which genre traditions and communicative instruments were used and which changing political implications those performances were based on. To achieve this goal, the archive sources, selected texts of theatrical performances, reports and reviews in daily press have been evaluated.     

Identification of “nodule-specific” host proteins (nodulins) involved in the development of Rhizobium-Legume symbiosis

Infection of legume roots with Rhizobium species results in the development of a root nodule structure in which the bacteria form an intracellular symbiosis with the plant. We report here that the infection of soybean (Glycine max L.) roots with Rhizobium japonicum results in the synthesis by the plant of at least 18–20 polypeptides other than leghemoglobin during the development of root nodules. Identification of these “nodule-specific” host polypeptides (referred to as nodulins) was accomplished by two-dimensional gel analysis of the immunoprecipitates formed by a “nodule-specific” antiserum with in vitro translation products of root-nodule polysomes that are free of bacteroidal contaminations. Nodulins account for 7–11% of the total ³⁵S-methionine-labeled protein synthesized in the host cell cytoplasm, and the majority of them are of 12,000–20,000 molecular weight. These proteins are absent from the uninfected roots, bacteroids and free-living Rhizobium, and appear to be coded for by the plant genes that may be obligatory for the development of symbiosis in the legume root nodules. Analysis of nodulins in ineffective (unable to fix nitrogen) nodules developed due to Rhizobium strains SM5 and 61A24 showed that their synthesis is reduced and their expression differentially influenced by mutations in rhizobia. Two polypeptides of bacterial origin were also found to be cross-reactive with the “nodule-specific” antiserum, suggesting that they are secreted by Rhizobium into the host cell cytoplasm during symbiotic nitrogen fixation.     

Structure-guided engineering of TGF-βs for the development of novel inhibitors and probing mechanism

The increasing availability of detailed structural information on many biological systems provides an avenue for manipulation of these structures, either for probing mechanism or for developing novel therapeutic agents for treating disease. This has been accompanied by the advent of several powerful new methods, such as the ability to incorporate non-natural amino acids or perform fragment screening, increasing the capacity to leverage this new structural information to aid in these pursuits. The abundance of structural information also provides new opportunities for protein engineering, which may become more and more relevant as treatment of diseases using gene therapy approaches become increasingly common. This is illustrated by example with the TGF-β family of proteins, for which there is ample structural information, yet no approved inhibitors for treating diseases, such as cancer and fibrosis that are promoted by excessive TGF-β signaling. The results presented demonstrate that through several relatively simple modifications, primarily involving the removal of an α-helix and replacement of it with a flexible loop, it is possible to alter TGF-βs from being potent signaling proteins into inhibitors of TGF-β signaling. The engineered TGF-βs have improved specificity relative to kinase inhibitors and a much smaller size compared to monoclonal antibodies, and thus may prove successful as either as an injected therapeutic or as a gene therapy-based therapeutic, where other classes of inhibitors have failed.     

Negative regulation of TGF-β signaling in development

The TGF-β superfamily members have important roles in controlling patterning and tissue formation in both invertebrates and vertebrates. Two types of signal transducers, receptors and Smads, mediate the signaling to regulate expression of their target genes. Despite of the relatively simple signal transduction pathway, many modulators have been found to contribute to a tight regulation of this pathway in a variety of mechanisms. This article reviews the negative regulation of TGF-β signaling with focus on its roles in vertebrate development.     

DCD – a novel plant specific domain in proteins involved in development and programmed cell death

Background  

Recognition of microbial pathogens by plants triggers the hypersensitive reaction, a common form of programmed cell death in plants. These dying cells generate signals that activate the plant immune system and alarm the neighboring cells as well as the whole plant to activate defense responses to limit the spread of the pathogen. The molecular mechanisms behind the hypersensitive reaction are largely unknown except for the recognition process of pathogens. We delineate the NRP-gene in soybean, which is specifically induced during this programmed cell death and contains a novel protein domain, which is commonly found in different plant proteins.     

The general occurrence of “plastid initials” and their development into plastids in cortical cells of woody plants in winter

Summary Electron microscopic studies revealed that plastid initials, presumed precursors of plastids, occur in cortical cells of the following plants studied in February and March: Betula ermanii Cham.; Prunus sargentii Rhed.; Pyrus communis L.; Ribes sinanense F. Maekawa; Salix matsudana Koidz. forma tortuosa Rhed.; and Sambucus sieboldiana var. miquelii Hara. Since plastid initials were found previously in Malus pumila Mill., Morus bombycis Koidz. and Populus euramericana cv. gelrica (Sagisaka 1991), plastid initials have been found in all woody plants examined to date. In P. euramericana cv. gelrica, at later stages of the development of the initials in March, the conglomerates of plastid initials became heterogeneous in terms of size, extent of thylakoid formation and ability to form starch granules. The formation of prolamellar structures was frequently observed in cells of Magnolia kobus var. borealis Sarg., which was sampled on April 19. These observations suggest the course of events in the development of the plastid initial and the continuity of the life of amyloplasts over a year in the life of woody plants.     

Targeting the hydrophobic region of Hsp90’s ATP binding pocket with novel 1,3,5-triazines

Heat shock protein 90 (Hsp90) is a molecular chaperone that plays an important role in regulating the maturation and stabilization of many oncogenic proteins. In an attempt to discover a new class of Hsp90 inhibitors, a series of 1,3,5-triazine compounds were rationally designed, synthesized, and their biological activities were evaluated. Compound 3b was found to degrade Hsp90’s client proteins of Her2, Met and Akt and to induce the expression level of Hsp70. The binding mode of 3b in the ATP-binding site of Hsp90 was predicted by the molecular docking.     

Enantioselective synthesis of derivatives and structure–activity relationship study in the development of NA255 as a novel host-targeting anti-HCV agent

Hepatitis C virus (HCV) infection represents a serious health-care problem. Previously we reported the identification of NA255 from our natural products library using a HCV sub-genomic replicon cell culture system. Herein, we report how the absolute stereochemistry of NA255 was determined and an enantioselective synthetic method for NA255 derivatives was developed. The structure–activity relationship of the NA255 derivatives and rat pharmacokinetic profiles of the representative compounds are disclosed.     

Safety of photosynthetic Synechococcus elongatus for in vivo cyanobacteria–mammalian symbiotic therapeutics

The cyanobacterium Synechococcus elongatus (SE) has been shown to rescue ischaemic heart muscle after myocardial infarction by photosynthetic oxygen production. Here, we investigated SE toxicity and hypothesized that systemic SE exposure does not elicit a significant immune response in rats. Wistar rats intravenously received SE (n = 12), sterile saline (n = 12) or E. coli lipopolysaccharide (LPS, n = 4), and a subset (8 SE, 8 saline) received a repeat injection 4 weeks later. At baseline, 4 h, 24 h, 48 h, 8 days and 4 weeks after injection, clinical assessments, blood cultures, blood counts, lymphocyte phenotypes, liver function tests, proinflammatory cytokines and immunoglobulins were assessed. Across all metrics, SE rats responded comparably to saline controls, displaying no clinically significant immune response. As expected, LPS rats exhibited severe immunological responses. Systemic SE administration does not induce sepsis or toxicity in rats, thereby supporting the safety of cyanobacteria–mammalian symbiotic therapeutics using this organism.     

Can mechanical forces be responsible for novel bone development and evolution in fishes?

Mechanical forces influence the induction, growth and maintenance of the vertebrate skeleton. Using the zebrafish, Danio rerio, we explore the hypothesis that mechanical forces can ultimately lead to the generation of skeletal evolutionary novelties by modifications of the mechano‐responsive molecular pathways. Locomotion and feeding in zebrafish larvae begin early in ontogeny and it is likely that forces incurred during these behaviours affect subsequent skeletal development. We provide two case studies in which our hypothesis is being tested: the kinethmoid and intermuscular bones. The kinethmoid is a synapomorphy for the order Cypriniformes and is intricately linked to the bones of the protrusible upper jaw. It undergoes chondrogenesis within a ligament well after muscular forces are present within the head. Subsequent ossification of the kinethmoid occurs at sites of ligamentous attachment, leading us to believe that mechanical forces are involved. Unlike the kinethmoid, which has evolved only once, intermuscular bones have evolved several times during teleostean evolution. Intermuscular bones are embedded within the myosepta, the collagenous sheets between axial muscles. The effect of mechanical forces on the development of these intermuscular bones is experimentally tested by increasing the viscosity of the water in which larval zebrafish are raised. Since locomotion in high viscosity requires greater muscular forces, we can directly test the influence of mechanical forces on the development of intermuscular bones. Using developmental techniques paired with outgroup comparison for the kinethmoid, and direct experimentation for intermuscular bones, our case studies provide complementary insights into the effects of mechanical forces on the evolution of skeletal novelties in fishes.     

A novel non-symbiotic hemoglobin from oak: Roles in root signalling and development?

The cellular and molecular adaptations of non-model woody species to environmental changes are still poorly understood. We have cloned and characterised a novel non-symbiotic hemoglobin from oak roots (QpHb1) which exhibits a specific cellular distribution in the root. The QpHb1 gene is strongly expressed in the protoderm and the protoxylem cells in two Quercus species (Q. petraea and Q. robur) with contrasting adaptive potential to drought and flooding. The constitutive expression of QpHb1 in both oak species in specific root tissues combined with the reported presence of nitric oxide in the same tissues and its potential for protein S-nitrosylation could support a role for non-symbiotic hemoglobins in signalling changes in the root environment and/or in controlling some aspects of root development.Key words: nonsymbiotic haemoglobin, oak (Quercus), in situ hybridization, signalling, xylem, root, nitric oxide     

Immunocytochemical localization of a novel pituitary polypeptide “7B2” in the gastro-intestinal tract of the rat

Summary Immunoreactivity to the polypeptide designated 7B2 recently isolated from human and porcine pituitary glands, appears to be consistently confined to neuroendocrine and endocrine cells in various tissues. In rat gut, immunoreactive 7B2 was found in endocrine-paracrine cells. Highly labeled cells were found in the antrum of the stomach and, cells with lower concentrations, in the fundus, duodenum, jejunum and ileum. Except for a few cells which were simultaneously positive for 5-hydroxytryptamine, and a few others showing Grimelius's reaction, 7B2 cells do not exhibit argentaffin and/or argyrophil character. The 7B2 polypeptide seems to be distributed amongst several different types of endocrine cells in the gut.     

The rôle of vitamins in plant development

The Botanical Review -