Genomics and proteomics approaches to the study of cancer-stroma interactions

<p>Abstract</p> <p>Background</p> <p>The development and progression of cancer depend on its genetic characteristics as well as on the interactions with its microenvironment. Understanding these interactions may contribute to diagnostic and prognostic evaluations and to the development of new cancer therapies. Aiming to investigate potential mechanisms by which the tumor microenvironment might contribute to a cancer phenotype, we evaluated soluble paracrine factors produced by stromal and neoplastic cells which may influence proliferation and gene and protein expression.</p> <p>Methods</p> <p>The study was carried out on the epithelial cancer cell line (Hep-2) and fibroblasts isolated from a primary oral cancer. We combined a conditioned-medium technique with subtraction hybridization approach, quantitative PCR and proteomics, in order to evaluate gene and protein expression influenced by soluble paracrine factors produced by stromal and neoplastic cells.</p> <p>Results</p> <p>We observed that conditioned medium from fibroblast cultures (FCM) inhibited proliferation and induced apoptosis in Hep-2 cells. In neoplastic cells, 41 genes and 5 proteins exhibited changes in expression levels in response to FCM and, in fibroblasts, 17 genes and 2 proteins showed down-regulation in response to conditioned medium from Hep-2 cells (HCM). Nine genes were selected and the expression results of 6 down-regulated genes (<it>ARID4A</it>, <it>CALR</it>, <it>GNB2L1</it>, <it>RNF10</it>, <it>SQSTM1</it>, <it>USP9X</it>) were validated by real time PCR.</p> <p>Conclusions</p> <p>A significant and common denominator in the results was the potential induction of signaling changes associated with immune or inflammatory response in the absence of a specific protein.</p

Radiolabelled peptides for oncological diagnosis

Radiolabelled receptor-binding peptides targeting receptors (over)expressed on tumour cells are widely under investigation for tumour diagnosis and therapy. The concept of using radiolabelled receptor-binding peptides to target receptor-expressing tissues in vivo has stimulated a large body of research in nuclear medicine. The 111In-labelled somatostatin analogue octreotide (OctreoScan™) is the most successful radiopeptide for tumour imaging, and was the first to be approved for diagnostic use. Based on the success of these studies, other receptor-targeting peptides such as cholecystokinin/gastrin analogues, glucagon-like peptide-1, bombesin (BN), chemokine receptor CXCR4 targeting peptides, and RGD peptides are currently under development or undergoing clinical trials. In this review, we discuss some of these peptides and their analogues, with regard to their potential for radionuclide imaging of tumours

Internal Residual Stress Measurements in a Bioactive Glass-Ceramic Using Vickers Indentation

The residual stress distribution that arises in the glass matrix during cooling of a partially crystallized 17.2Na(2)O-32.1CaO-48.1SiO(2)-2.5P(2)O(5) (mol%) bioactive glass-ceramic was measured using the Vickers indentation method proposed by Zeng and Rowcliffe (ZR). The magnitude of the determined residual stress at the crystal/glass boundary was 1/4-1/3 of the values measured using X-ray diffraction (within the crystals) and calculated using Selsing`s model. A correction for the crack geometry factor, assuming a semi-elliptical shape, is proposed and then good agreement between experimental and theoretical values is found. Thus, if the actual crack geometry is taken into account, the indentation technique of ZR can be successfully used. In addition, a numerical model for the calculation of residual stresses that takes into account the hemispherical shape of the crystalline precipitates at a free surface was developed. The result is that near the sample surface, the radial component of the residual stress is increased by 70% in comparison with the residual stress calculated by Selsing`s model.CNPq/Brazil[151917/2006-0]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fapesp/Brazil[07/08179-9

In vitro and in vivo studies on CCR10 regulation by Annexin A1

The mode of action of annexin A1 (ANXA1) is poorly understood. By using rapid subtraction hybridization we studied the effects of human recombinant ANXA1 and the N-terminal ANXA1 peptide on gene expression in a human larynx cell line. Three genes showed strong downregulation after treatment with ANXA1. In contrast, expression of CCR10, a seven transmembrane G-protein coupled receptor for chemokine CCL27 involved in mucosal immunity, was increased. Moreover the reduction in CCR10 expression induced by ANXA1 gene deletion was rescued by intravenous treatment with low doses of ANXA1. These findings provide new evidence that ANXA1 modulates gene expression. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved

Internal Residual Stresses in Sintered and Commercial Low Expansion Li(2)O-Al(2)O(3)-SiO(2) Glass-Ceramics

We performed Synchrotron X-ray diffraction (XRD) analyses of internal residual stresses in monolithic samples of a newly developed Li(2)O-Al(2)O(3)-SiO(2) (LAS) glass-ceramic produced by sintering and in a commercial LAS glass-ceramic, CERAN (R), produced by the traditional crystal nucleation and growth treatments. The elastic constants were measured by instrumented indentation and a pulse-echo technique. The thermal expansion coefficient of virgilite was determined by high temperature XRD and dilatometry. The c-axis contracts with the increasing temperature whereas the a-axis does not vary significantly. Microcracking of the microstructure affects the thermal expansion coefficients measured by dilatometry and thermal expansion hysteresis is observed for the sintered glass-ceramic as well as for CERAN (R). The measured internal stress is quite low for both glass-ceramics and can be explained by theoretical modeling if the high volume fraction of the crystalline phase (virgilite) is considered. Using a modified Green model, the calculated critical (glass) island diameter for spontaneous cracking agreed with experimental observations. The experimental data collected also allowed the calculation of the critical crystal grain diameters for grain-boundary microcracking due to the anisotropy of thermal expansion of virgilite and for microcracking in the residual glass phase surrounding the virgilite particles. All these parameters are important for the successful microstructural design of sintered glass-ceramics.CNPq/Brazil[151917/2006-0]FAPESP/Brazil[07/08179-9]FAPESP/Brazil[05/53241-9]CNPqBrazilian Synchrotron Light Laboratory (LNLS)/MCT[XRD1-5824]Brazilian Synchrotron Light Laboratory (LNLS)/MCT[XRD1-6712

Effect of magnesium ion incorporation on the thermal stability, dissolution behavior and bioactivity in bioglass-derived glasses

There is a strong discrepancy in the literature regarding the effect of magnesium on bioactive glasses. Hence the present study is focused on the physical and chemical behavior of the "golden standard" 45S5 glass and magnesium-containing bioactive glasses developed here to evaluate their reactivity and in vitro bioactivity. The aimof this study was to analyze the influence of CaO replacement by MgO, especially its effect on the rate of formation of the apatite-like layer at the glass surface, the reaction kinetics between the glasses and simulated body fluid (SBF-K9) and on the glass stability against devitrification during heating. Five melt-derived bioactive glasses of the system 24.3Na2O-26.9(xCaO-(1-x)MgO)-46.3SiO2-2.5P2O5 (x=1; 0.875; 0.75; 0.625 and 0.5) were synthesized with CaO progressively replaced by MgO.Their thermal stability on heating was characterized by DSC analysis. Their degradation and ability to form an apatite-like layer were evaluated through in vitro tests by immersion in SBF-K9; FTIR, ion selective electrode analysis and by solid state nuclear magnetic resonance (NMR) spectroscopy. Our results indicate that magnesium plays an important role in the stability of this glass family, defined as the difference between the glass transition temperature Tg and crystallization temperature Tx. The lower Tg observed in the MgO-rich glasses and insignificantly changed solubilities, as well as the 29Si NMR results suggest that in this glass system MgO does not act as a network intermediate or former oxide, but as network modifier, aswe expected. Dissolution kinetics, FTIR, and solid state 31P and 1HMAS-NMR consistently indicate that partial replacement of CaO by MgO in the bioglass does not influence the rate at which the initial amorphous calciumphosphate (ACP) layer is precipitated when the glass is exposed to SBF. In contrast it greatly reduces the rate of conversion of this precursor phase to the crystalline hydroxycarbonate apatite (HCA)-layer.CNPqFAPESP (13/07793-6