Nelson, Paul N.; Astley, S.J.; Roden, Denise A.; Waldron, E.E.; Baig, K.M.; Caforio, A.L.; Koutedakis, Yiannis; Perera, Shantha; Spry, C. (New Rochelle (NY): Mary Ann Liebert, Inc., 2005)
The characterization of monoclonal antibodies (MAbs) with regard to reactivity and specificity is important for the successful application as a molecular probe and/or diagnostic reagent. Furthermore, it is recognized that some monoclonal reagents perform well in some assay systems but not others. In this study, the reactivity profiles of two anti-myosin MAbs (H1 and DH2, raised against human cardiac myosin) were evaluated in enzyme-linked immunosorbent assay (ELISA), slot-blotting, and immunocytochemistry. Both antibodies performed well in slot-blotting against myosin heavy chain preparations from cardiac and skeletal muscle and from non-human sources. In general, MAb H1 demonstrated strong to moderate reactivity in all assay systems, whilst MAb DH2 faired poorly in ELISA. MAb H1 also showed reactivity to synthetic peptides of myosin, one of which possessed a motif (ERRDA, single amino acid code) that was found in other human and nonhuman myosin protein sequences that could explain its cross-reactive profile. Intriguingly, this motif was found on viral and other pathogenic agents associated with myocarditis. Hence, it is speculated that this region could give some credence to the mechanism of molecular mimicry associated with some cardiac diseases. Overall, MAb H1 may serve as a useful probe of myosin structure.
Nelson, Paul N.; Westwood, Olwyn M. R.; Freimanis, Graham L.; Roden, Denise A.; Sissaoui, Samir; Rylance, Paul; Hay, Frank C. (Libertas Academica Press, 2008)
Epitope mapping allowed the location of antigenic determinants on a protein macromolecule to be identified. In particular, pepscan techniques that utilize a series of overlapping peptides, help detect key amino acid residues that are important in antibody recognition and binding. In a previous study, we employed 15-mer peptides spanning the entire length of IgG1Fc to ascertain successfully the target epitopes of isotypic/allotypic monoclonal reagents. As an extension to this work we have used these peptides to evaluate the location of epitope targets of five IgM rheumatoid factor antibodies (RFAbs). Overall, 2 antibodies, RFAb TS2 and TS1, detected a similar epitope within the CH3 domain (360-KNQVSLTCLVKGFYP-374), whilst 1 (RFAb SJ1) recognised an epitope in the CH2 domain (294- EQYNSTYRVVSVLTV-308). In contrast, 2 RFAbs, PRSJ2 and PRTS1 detected four and five epitopes respectively within the Fc region. RFAb PRSJ2 recognised epitopes detected by RFAB TS2 and TS1 but also further epitopes in the CH2 domain (256-TPEVTCVVVDVSHED-270) and CH3 domain (418-QQGNVFSCSVMHEAL-432). Similarly, RFAb PRTS1 detected all four epitopes plus a fifth in the CH3 domain (382-ESNGQPENNYKTTPP-396). In essence there was a consensus of target epitopes identified by these rheumatoid factor antibodies. Interestingly, two epitopes (256–270, CH2 domain and 360–374, CH3 domain) were novel in that they had not been identified in previous pepscan studies. The other epitopes recognised, either overlapped or were immediately adjacent to previous epitopes detected by poly/monoclonal rheumatoid factor antibodies. Molecular modelling (PCImdad) of IgG1Fc showed that all five epitopes were exposed and surface accessible for antibody interaction. In addition, a bioinformatics analysis of the Fc region using ExPASy was employed to identify key antigenic determinants. This ‘in silico’ approach may provide a means of determining key regions without the need to develop overlapping peptides spanning the entire length of a macromolecule.
Suarez-Merino, Blanca; Hubank, Mike; Hayward, Richard; Harkness, William; Thompson, Dominic; Phipps, Kim; Revesz, Tamas; Darling, John L.; Thomas, David G.; Warr, Tracy (Society for Neuro-Oncology and Duke University Press, 2003)
Ependymomas arise from the ependymal cells lining the ventricular system of the CNS and account for approximately 10% of paediatric brain tumours. Approximately 70% of ependymomas are histologically benign and correspond to WHO grade II, whilst the remainder are anaplastic (WHO grade III). The 5-year survival rates in children are 34–45%, with local recurrence being the major source of therapeutic failure. Anaplasia does not appear to be associated with worse prognosis, and at present there are no molecular or genetic markers which can be used as predictors of outcome. Indeed, the genetic events that contribute to the pathogenesis of ependymoma are essentially unknown. We have used human oligonucleotide arrays to generate gene expression profiles in 10 ependymoma samples from patients with different histopathological/clinical parameters in order to identify new prognostic markers. Our sample group is composed of 7 ependymoma (WHO grade II) and 3 anaplastic ependymoma (WHO grade III). Three patients were <3 years of age at first presentation. Five tumours have chromosomal aberrations identified by comparative genomic hybridisation (CGH). Our preliminary data show that overexpression of specific functional categories of genes is dependant on histology when compared to normal controls. Cell cycle and adhesion related genes, oncogenes, and genes involved in apoptosis were mainly overexpressed in anaplastic tumours. Benign tumours, however, overexpressed mainly growth factor related genes. Some common candidates emerged for all tumours; Wee1+, a cell cycle related gene that regulates entry into mitosis, was up to six fold overexpressed in tumours. The oncogene c-myc, which maps to an amplicon at 8q24 detected by CGH in a subset of ependymomas, was also overexpressed in some tumours and may be an interesting candidate in their development. To our knowledge, none of these genes have been associated previously with this class of brain tumours. Further analysis of differential gene expression profiles using large series of tumours will help in the identification of molecular markers. This information, when linked to clinical and pathology data, could also help in the classification of these tumours and the choice of therapy.
Darling, John L. (Czech Republic: Palacky University, Olomouc: Faculty of Medicine and Dentistry, 2006)
Although in comparison to breast, lung and colon cancer, the brain is a relatively uncommon site for the development of cancer, the brain is the tenth most common site for the development of cancer in men and about the twelfth in women. This translates to about 6,000 individuals in the UK developing a primary malignant brain tumour every year. Cancer of the brain develops in two distinct age groups, although the types of tumour that develop in these two age groups differ markedly. There is a peak of incidence in the first decade of life, and brain tumours rank with leukaemia as a leading cause of cancer death in children. These tumours tend to be indolent low-grade astrocytomas or highly malignant primitive neuroectodermal tumours like medulloblastoma. However, the vast majority of brain tumours occur with increasing frequency in the sixth, seventh and eight decade of life and they are the second fastest growing cause of cancer death among those over 65. These tumours tend to be malignant astrocytomas particularly the most malignant variety, glioblastoma multiforme (GBM). Unlike lung cancer or malignant melanoma there is no strong evidence of an environmental carcinogen associated with the development of these tumours and no change in behaviour reduces risk.
Ward, Samantha; Hayward, Richard; Harkness, William; Phipps, Kim; Thompson, Dominic; Harding, Brian; Wilkins, Peter; Darling, John L.; Thomas, David G.; Warr, Tracy (Society for Neuro-Oncology and Duke University Press, 2003)
Glial cell tumours represent the largest group of brain tumours in childhood and include astrocytoma (WHO grades I-IV) and ependymoma (WHO grade II-III). However, little is known about the pathogenesis of these tumours. We have used comparative genomic hybridisation (CGH) to investigate the genetic alterations in 128 tumours from children and young adults (< 30 years of age) comprising 52 ependymoma, including 40 samples that have previously been reported (44 grade II and 8 grade III) and 76 astrocytoma (consisting of 34 grade I, 17 grade II, 7 grade III, and 18 grade IV). Genetic alterations were compared to clinicopathological data such as histology, tumour recurrence, and survival in order to identify potential prognostic markers. In ependymoma, 39% of the tumours had no detectable copy number aberrations (CNAs). In the remaining tumours, the most common regions of gain were 4q (29%), 6q (21%), 1q (17%), and 2q (15%). The most common regions of loss were 22 (29%), 16p (17%), 17p (13%), and 20q (13%). Three regions of high copy number amplification were observed in 3 tumours at 1q24-31 (3 cases), 8q21-23 (3 cases), and 9p (1 case). There was no association between any CNA and histology, tumour recurrence, or length of survival. In contrast, in the astrocytoma group there was a clear association between histology and the presence of CNAs. The pattern of genetic alterations became increasingly complex with tumour grade, and grade IV tumours were more likely to have CNAs than lower grade tumours (p = 0.0502). Overall, the most frequent alterations observed in astrocytoma were gain of 4q (11%), loss 16p (10.5%), and loss 17p (10.5%). However, several CNAs were seen predominantly in grade IV tumours (gain 1q, 2q, 4q, and 5q). Fourteen amplicons were observed in 8 tumours of all grades, of which the most common were localised to 7q31 (4 cases), 8q21-22 (3 cases), 19p (2 cases), 2q (2 cases), and 12q15-21 (2 cases). From this study, it appears that paediatric glial tumours are much more genetically heterogeneous than their adult counterparts, and further molecular investigations are needed to define clinically useful subgroups.
Jones, Sarah; Howl, John D. (Society for Neuro-oncology and Duke University Press, 2005)
The cell-type-specific targeting of cytotoxic agents and other functional moieties can be achieved by using peptidyl address motifs that selectively bind protein targets expressed at high density at the cell membrane. Indeed, numerous studies have confirmed the utility of ligands for G protein–coupled receptors as components of heterofunctional peptide chimeras that are selective biological probes. Our current efforts are directed toward the further development of chimeric peptidyl constructs that employ sequences derived from GPCR ligands or cell penetrant motifs to affect the selective delivery of cytotoxins and signal transduction modulators to tumor cells. We have designed and synthesized a range of hybrid constructs consisting of cytotoxins (peptide and non-peptide) covalently linked to an address peptide derived from the C-terminal of gastrin (G7; H-AYGWMDF-NH2). The G7 homing motif targets a novel binding site expressed by U373MG astrocytic tumor cells that is distinct from classical CCK1/CCK2 receptors. Moreover, biological responses following activation of this novel membrane-bound protein may offer additional therapeutic advantages. For example, G7 receptor activation is reported to inhibit the motility of malignant astrocytoma in vivo while avoiding the growth-promoting effects of gastrin (Pannequin et al., J. Pharmacol. Exp. Ther. 302, 274, 2002). We evaluated the cytotoxicity of our chimeric peptides by comparing changes in cellular viability using MTT conversion assays. Our data indicate that chimeric peptides dose-dependently and rapidly (<8 h) reduced the viability of U373MG cells. Moreover, as a chimeric amino-terminal extension, the G7 address motif enhanced the cytotoxicity of both mastoparan (H-INLKALAALAKKIL-NH2) and D(KLAKLAK)2 peptides reported to stimulate necrosis and/or apoptosis of eukarytoic cells. In conclusion, hybrid G7 chimeras enhance the efficacy of cytotoxic agents and may be valuable probes to investigate and manipulate additional aspects of astrocytoma cell biology. This work was supported by The Wellcome Trust.
Westwood, Olwyn M. R.; Nelson, Paul N.; Hay, Frank C. (Oxford: Oxford Journals, 2006)
Rheumatoid arthritis (RA) is a classic example of an autoimmune disorder, with chronic inflammation of the synovial membrane, and deterioration of cartilage and bone in the affected joints. The resultant pain, loss of function and permanent disability are also associated with increased morbidity and mortality.
Jones, Sarah; Ostlund, Pernilla; Langel, Ulo; Zorko, Matjaz; Nicholl, Iain D.; Howl, John D. (Wiley InterScience, 2006)
INTRODUCTION: Many cell-penetrating peptides (CPP) have been utilised as biologically inert vectors. A majority of these studies employ sychnologically organised constructs in which a bioactive cargo (message) is chemically conjugated to the CPP (address). Previously, we have adopted a sychnologic strategy to modulate intracellular signal transduction. Using chimeric constructs composed of the CPP transportan 10, conjugated to partial sequences that correspond to functional domains of signal transduction proteins, we have selectively modulated a variety of cellular activities including secretion and activation of p42/p44 mitogen-activated protein kinases [1, 2]. However, a QSAR-based algorithm can now be used to predict CPP that reside within the primary sequences of proteins . We have adapted this strategy to identify CPP within signal transducing proteins including functional domains that govern protein-protein interactions. Data presented herein indicate that it is now feasible to identify rhegnylogic sequences, containing vectoral-independent discontinuously organised pharmacophores, that are cell penetrant modulators of signal transduction pathways.
Jones, Sarah; Howl, John D. (Washington, D.C.: CRC Press, 2006)
THIS BOOK: Since the first Handbook of Cell-Penetrating Peptides was prepared in 2001, the wealth of new information on the use of these peptides as transport systems has in fact served to confound the field. The constant internal change in the field of cell-penetrating peptides (CPPs) is due to recent research uncovering apparent ambiguities in cellular uptake. There is still neither a common terminology nor a uniform explanation for the penetrative mechanism of cell-penetrating peptides. In this second edition of the Handbook of Cell-Penetrating Peptides, the authors summarize the current state of the field including recent reevaluations of earlier studies of CPP mechanisms. Beginning with an overview of the classes of peptides and their individual uptake mechanisms, from the earlier lipid models to the more recent endocytotic pathways, the book demonstrates the diversity and the opportunity for these biologically active proteins to serve as future drug leads. The text then covers the use of CPPs in gene modulation, addressing the application of antisense and decoy oligonucleotides, as well as the new avenue of research targeting specific tumors and other tissues-questions that had barely been asked when the first edition was published. (CRC Press)
Nelson, Paul N.; Shaw, M.; Roden, Denise A.; Freimanis, Graham L.; Nevill, Alan M.; Rylance, Paul (Czech Republic: Palacky University, Olomouc: Faculty of Medicine and Dentistry, 2006)
Human endogenous retroviruses (HERVs) are a group of integrated RNA viruses within our human genome. Whilst many are regarded as defective, a number possess the potential to generate retroviral products. Indeed HERVs such as those belonging to the HERV-K family produce retroviral particles in the teratocarcinoma cell line GH and the breast cancer cell line T47D. It has been argued that some retroelements may be beneficial to the human host, perhaps conferring a selective advantage, whereas others may be harmful. Furthermore certain HERVs might be involved in the pathogenesis of autoimmune diseases. The precise mechanisms in diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) may include molecular mimicry and superantigen motifs that evoke and augment unwarranted immune responses. The precise mechanisms in diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) may include molecular mimicry and superantigen motifs that evoke and augment unwarranted immune responses. In the RA joint, tissue destruction is evident over time with recruitment of lymphoid and other cells plus the presence of rheumatoid factor that exhibits increased affinity and change in isotype; evidence of an antigen-driven immune response. The precise trigger of course, remains unknown although certain HERVs have been implicated. In a previous study we found evidence for increased expression of HERV-K10 mRNA in patients with RA. Here we have extended this work by investigating the serological expression to HERV-K10 in patients with RA, SLE, osteoarthritis, normals and other inflammatory disease groups. The study utilised a novel peptide ELISA immunoassay using segments of HERV-K10 identified through bioinformatic analysis. In particular, biotinylation of peptides was necessary for serological discrimination between patients. Overall a significant difference (p<0.05) was found for RA patients in terms of antibody activity to HERV-K10. There was also an increased level of antibodies to HERV-K10 in patients with renal lupus although this was below the level of significance. It is possible that HERV-K10 could act as a trigger in RA/SLE through regions of similarity to host proteins. In this case, the immune response to HERV-K10 could lead to collateral damage and pathogenesis of disease.
The export option will allow you to export the current search results of the entered query to a file. Different
formats are available for download. To export the items, click on the button corresponding with the preferred download format.
By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.
To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export.
The amount of items that can be exported at once is similarly restricted as the full export.
After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.