[Laser microdissection applications in histology: an open way to molecular studies].

One of the most fascinating aspects of the use of a laser beam in the field of biology has emerged with the development of devices able to perform fine dissections of biological tissues. Laser microdissection can collect phenotypically identical cells from tissue regions laid on a microscope slide in order to make differential molecular analyses on these microdissected cells. Laser microdissection can be used many areas including oncology to specify molecular mechanisms that enable to adapt a treatment related to diagnosis and research in biology, but also forensic science for tissue selection, neurology for post-mortem studies on patients with Alzheimer's disease, for clonality studies from cell cultures and cytogenetics to decipher chromosomal rearrangements.

Transcriptional response to hypoxic stress in melanoma and prognostic potential of GBE1 and BNIP3.

Gradients of hypoxia occur in most solid tumors and cells found in hypoxic regions are associated with the most aggressive and therapy-resistant fractions of the tumor. Despite the ubiquity and importance of hypoxia responses, little is known about the variation in the global transcriptional response to hypoxia in melanoma. Using microarray technology, whole genome gene expression profiling was first performed on established melanoma cell lines.

Genetic and pharmacological inhibition of microRNA-92a maintains podocyte cell cycle quiescence and limits crescentic glomerulonephritis.

Crescentic rapidly progressive glomerulonephritis (RPGN) represents the most aggressive form of acquired glomerular disease. While most therapeutic approaches involve potentially toxic immunosuppressive strategies, the pathophysiology remains incompletely understood. Podocytes are glomerular epithelial cells that are normally growth-arrested because of the expression of cyclin-dependent kinase (CDK) inhibitors.

Towards better digital pathology workflows: programming libraries for high-speed sharpness assessment of Whole Slide Images.

Background: Since microscopic slides can now be automatically digitized and integrated in the clinical workflow, quality assessment of Whole Slide Images (WSI) has become a crucial issue. We present a no-reference quality assessment method that has been thoroughly tested since 2010 and is under implementation in multiple sites, both public university-hospitals and private entities. It is part of the FlexMIm R&D project which aims to improve the global workflow of digital pathology.

Stability of preclinical models of aggressive renal cell carcinomas.

Renal-cell carcinomas (RCC) are often resistant to conventional cytotoxic agents. Xenograft models are used for in vivo preclinical studies and drug development. The validity of these studies is highly dependent on the phenotypic and genotypic stability of the models.

Assessment of chimerism in epithelial cancers in transplanted patients.

Cancer is now the most severe complication in the long term in transplant recipients. As most solid-organ or hematopoietic stem-cell transplantations are allogeneic, chimerism studies can be performed on cancers occurring in recipients. We summarize here the different methods used to study chimerism in cancers developing in allogeneic-transplant recipients, analyze their respective advantages and report the main results obtained from these studies.

Beyond laser microdissection technology: follow the yellow brick road for cancer research.

Normal biological tissues harbour different populations of cells with intricate spacial distribution patterns resulting in heterogeneity of their overall cellular composition. Laser microdissection involving direct viewing and expertise by a pathologist, enables access to defined cell populations or specific region on any type of tissue sample, thus selecting near-pure populations of targeted cells. It opens the way for molecular methods directed towards well-defined populations, and provides also a powerful tool in studies focused on a limited number of cells.

Concomitant multipotent and unipotent dental pulp progenitors and their respective contribution to mineralised tissue formation.

Upon in vitro induction or in vivo implantation, the stem cells of the dental pulp display hallmarks of odontoblastic, osteogenic, adipogenic or neuronal cells. However, whether these phenotypes result from genuine multipotent cells or from coexistence of distinct progenitors is still an open question. Furthermore, determining whether a single cell-derived progenitor is capable of undergoing a differentiation cascade leading to tissue repair in situ is important for the development of cell therapy strategies.

Early atheroma-derived agonists of peroxisome proliferator-activated receptor-γ trigger intramedial angiogenesis in a smooth muscle cell-dependent manner.

Rationale: Neovascularization favors intraplaque hemorrhage and plaque rupture. Development of therapeutic strategies against atheromatous angiogenesis requires elucidation of its initiating factors.

Objective: We investigated the contribution of smooth muscle cells (SMCs) and atheroma-derived lipids to the initiation of atheroma-associated neoangiogenesis.

Immunohistochemical and molecular analyses of HER2 status in breast cancers are highly concordant and complementary approaches.

Background: Immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) are currently the most commonly used methods to assess HER2 status. PCR-based assays allow quantitative determination of HER2 amplification (Q-PCR) or overexpression (Q-RT-PCR), but are not routinely used. We evaluated the relevance of Q-RT-PCR for HER2 status determination.

Donor-derived oral squamous cell carcinoma after allogeneic bone marrow transplantation.

In animal models, tissue stem cells were proposed to exhibit an unexpected level of plasticity, although issues on cell fusions have lead to some controversies. Only transplantation experiments using genetically distinct recipients and donors can unequivocally show these changes in cell fate. We have analyzed oral squamous cell carcinomas arising in 8 long-term survivors of allogeneic bone marrow transplantation, in whom chronic graft-versus-host disease greatly favors development of squamous cell carcinomas, possibly as a consequence of lichenoid mucosal inflammation.

[On line digital microscopy in 2007: One technology, many uses].

Digital microscopy enables several observers to look at any field of one microscopical section, at any magnification, through an Internet connexion. An overview of the systems used to digitize microscopy slides and to put them on line is presented. This technique is already used in many fields of pathology, for teaching, research and, to a lesser extent, diagnostic purposes.

Changes in allelic imbalances in locally advanced breast cancers after chemotherapy.

In advanced breast cancers, TP53 mutation is highly predictive of complete response to high-dose epirubicin/cyclophosphamide chemotherapy. In these tumours with an altered control of genomic stability, accumulation of chemotherapy-induced genetic alterations may contribute to cell death and account for complete response. To explore the effects of chemotherapy on stability of the tumour genome, allelic profiles were obtained from microdissected tumour samples before and after chemotherapy in 29 unresponsive breast cancers (9 with TP53 mutation).

Disruption of T cell regulatory pathways is necessary for immunotherapeutic cure of T cell acute lymphoblastic leukemia in mice.

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. In recent years, the outcome has been globally improved by current therapies, but it remains poor in patients with high, persistent residual disease following the first course of chemotherapy, prompting evaluation of the possible beneficial effects of immunotherapy protocols. In this study, we hypothesized that the disruption of two immunoregulatory pathways controlling the auto-reactive T cell response might synergize with dendritic cell-based immunotherapy of the disease, which is considered to be poorly immunogenic.

Vascular endothelial growth factor-A is expressed both on lymphoma cells and endothelial cells in angioimmunoblastic T-cell lymphoma and related to lymphoma progression.

Vascular endothelial growth factor-A (VEGF-A), a main stimulator of endothelial cell proliferation, plays an important role on tumor angiogenesis. Angioimmunoblastic T-cell lymphoma (AITL) show the most prominent vascular component among lymphomas and their prognosis is difficult to predict. To assess the clinical significance of VEGF-A in AITL, VEGF-A gene expression was studied in the tumoral lymph nodes of 24 patients using laser microdissection and quantitative polymerase chain reaction.

Histochemical and immunohistochemical protocols for routine biopsies embedded in Lowicryl resin.

Tissue processing and analysis require good preservation of both the shape and content of cells. Lowicryl resin is one of the few embedding media that allow good preservation of both tissue architecture and cellular contents. Therefore, different histochemical and immunohistochemical reactions can be applied to semithin sister sections from one biopsy.

DC-SIGN is the major Mycobacterium tuberculosis receptor on human dendritic cells.

Early interactions between lung dendritic cells (LDCs) and Mycobacterium tuberculosis, the etiological agent of tuberculosis, are thought to be critical for mounting a protective anti-mycobacterial immune response and for determining the outcome of infection. However, these interactions are poorly understood, at least at the molecular level. Here we show that M.

Autonomous rexinoid death signaling is suppressed by converging signaling pathways in immature leukemia cells.

On their own, retinoid X receptor (RXR)-selective ligands (rexinoids) are silent in retinoic acid receptor (RAR)-RXR heterodimers, and no selective rexinoid program has been described as yet in cellular systems. We report here on the rexinoid signaling capacity that triggers apoptosis of immature promyelocytic NB4 cells as a default pathway in the absence of survival factors. Rexinoid-induced apoptosis displays all features of bona fide programmed cell death and is inhibited by RXR, but not RAR antagonists.

Alteration of the sphingomyelin/ceramide pathway is associated with resistance of human breast carcinoma MCF7 cells to tumor necrosis factor-alpha-mediated cytotoxicity.

The interference of tumor necrosis factor-alpha (TNF) signaling processes with the acquisition of tumor resistance to TNF was investigated using the TNF-sensitive human breast carcinoma MCF7 cell line and its established TNF-resistant variant (R-A1). The resistance of R-A1 cells to TNF correlated with a low level of p55 TNF receptor expression and an absence of TNF signaling through TNF receptors. Stable transfection of wild-type p55 receptor in R-A1 resulted in enhancement of p55 expression and in partial restoration of TNF signaling, including nuclear factor-kappaB (NF-kappaB) activation.

In-vivo effect of the combination of tnf and adriamycin against a human breast cell-line expressing the mdr-phenotype.

The combined effect of tumor necrosis factor alpha (TNF) and adriamycin (ADR) on tumor cell killing was investigated in vivo. The human breast adenocarcinoma ADR-resistant MDA/ADR cells found to be resistant to in vitro TNF lysis and with an apparent index of resistance to ADR of 23 have been used. Treatment of MDA/ADR subcutaneous tumor bearing mice with PBS, TNF, ADR or the combination of TNF/ADR indicate that the combination of TNF and ADR treatment leads to a significant decrease in tumor growth while treatment with TNF was inactive and treatment with ADR was moderately active.

Evidence for the binding of a biologically active interleukin-2 to human alpha 2-macroglobulin.

Human alpha 2-macroglobulin (alpha 2M), which irreversibly entraps proteinases through a drastic conformational change, has also been reported to bind various cytokines. The meaning of cytokine binding to native and/or transformed alpha 2M molecules is, however, not understood. In an attempt to elucidate this question, we have studied the interaction of radioiodinated recombinant human interleukin-2 (125I-rhIL-2) with native and chymotrypsin (alpha 2M-C)- or methylamine-transformed (alpha 2M-MA) alpha 2M.

Activation of nuclear protooncogenes and alpha-fetoprotein gene in rat liver during the acute inflammatory reaction.

Nuclear protooncogene and alpha-fetoprotein gene expression is stimulated in hepatocytes during liver regeneration and by various growth factors in vitro. Metabolic adaptation of hepatocytes has been implicated in such gene reprogrammation. We examine here whether induction of an acute inflammation, a physiological situation of important metabolic adjustments, also triggers activation of nuclear oncogenes and of the AFP gene in rat liver.

Structural and functional studies on the human interleukin-6 receptor. Binding, cross-linking, internalization, and degradation of interleukin-6 by fibroblasts transfected with human interleukin-6-receptor cDNA.

A cDNA coding for the human interleukin-6 receptor (IL-6-R) has been expressed stably in murine NIH/3T3 fibroblasts. Transfected cells exhibited a single class of binding sites for 125I-labeled recombinant human interleukin-6 (125I-rhIL-6) (Kd = 440 pM, 20,000 receptors per cell). Affinity cross-linking of 125I-rhIL-6 to the IL-6-R-expressing NIH/3T3 cells led to the detection of three 125I-rhIL-6-containing protein complexes with molecular masses of 100, 120, and 200 kDa suggesting a complex organization of the IL-6-R in the plasma membrane.