Search results for "tumor cell"
showing 10 items of 694 documents
Evaluation of consistency in spheroid invasion assays
2016
Multicellular tumor spheroids embedded in a matrix represent invaluable tools to analyze cell invasion. Spheroid sizes and invasiveness are the main observables easily measurable to evaluate effects of biological or pharmaceutical manipulations on invasion. They largely account for these 3-D platforms variability, leading to flaws in data interpretation. No method has been established yet that characterizes this variability and guarantees a reliable use of 3-D platforms. Spheroid initial/end sizes and invasiveness were systematically analyzed and compared in spheroids of U87MG cells generated by three different methods and embedded at different times in a collagen matrix. A normality test w…
Tumor Control in a Model of Bone Marrow Transplantation and Acute Liver-Infiltrating B-Cell Lymphoma: an Unpredicted Novel Function of Cytomegalovirus
2002
ABSTRACTTumor relapse and cytomegalovirus (CMV) infection are major concerns in the therapy of hematopoietic malignancies by bone marrow transplantation (BMT). Little attention so far has been given to a possible pathogenetic interplay between CMV and lymphomas. CMV inhibits stem cell engraftment and hematopoietic reconstitution. Thus, by causing maintenance of bone marrow aplasia and immunodeficiency, CMV could promote tumor relapse. Alternatively, CMV could aid tumor remission. One might think of cytopathogenic infection of tumor cells, induction of apoptosis or inhibitory cytokines, interference with tumor cell extravasation or tumor vascularization, or bystander stimulation of an antitu…
Interferon-alpha inhibits hepatitis C virus subgenomic RNA replication by an MxA-independent pathway.
2001
Hepatitis C virus (HCV) persists in the majority of infected individuals and is a major cause of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Chronic hepatitis C is currently treated with interferon (IFN)-α or with a combination of IFN-α and ribavirin. The availability of an HCV replicon system (Lohmann et al., Science 285, 110–113, 1999) allowed the investigation of the effects of IFN on genuine HCV replication in cultured cells. It is shown here that IFN-α inhibits subgenomic HCV RNA replication in HuH-7 human hepatoma cells. Immunofluorescence, Western blot and Northern blot analysis revealed that levels of both HCV protein and replicon RNA were reduced after treatme…
In Vivo Observations on Tumor Invasion
1989
Tumor invasion in vivo is a very complex and dynamic process which depends upon a variety of interactions between heterogeneous tumor cell populations and the different cellular and extracellular components of the host tissue. This situation cannot be reproduced even in the most sophisticated in vitro system. On the other hand, there is at present no method available for a direct and dynamic observation of tumor invasion deep in the nontransparent living tissue, so that all evidence has to be derived from indirect observations made on the basis of static morphology. But all these limitations do not deny the potential value of in vivo investigations in following the natural course of tumor i…
Plexin-B1 and Semaphorin 4D Cooperate to Promote Perineural Invasion in a RhoA/ROK-Dependent Manner
2012
Perineural invasion (PNI) is a tropism of tumor cells for nerve bundles located in the surrounding stroma. It is a pathological feature observed in certain tumors, referred to as neurotropic malignancies, that severely limits the ability to establish local control of disease and results in pain, recurrent growth, and distant metastases. Despite the importance of PNI as a prognostic indicator, its biological mechanisms are poorly understood. The semaphorins and their receptors, the plexins, compose a family of proteins originally shown to be important in nerve cell adhesion, axon migration, and proper central nervous system development. Emerging evidence has demonstrated that these factors a…
Differentiation of Y79 cells induced by prolonged exposure to insulin
1997
Y79 human retinoblastoma cells are known to contain receptors for both insulin and insulin-like growth factors (IGFs), to produce these cytokines and release them in the culture medium. Previously we have demonstrated that IGFs and insulin stimulate Y79 cell proliferation through the involvement of type I IGF receptor and Insulin Receptor Substrate 1 (IRS-1). This paper studies the effect of prolonged exposure to insulin on Y79 cells. Cells grown for 10 days in the presence of insulin were reseeded and incubated once more with insulin. In the reseeded cells proliferation lowered and morphological changes appeared. After 10 days of reseeding, cells stopped proliferating and showed long ramif…
Uridine uptake inhibition as a cytotoxicity test for a human hepatoma cell line (HepG2 cells): comparison with the neutral red assay
2001
International audience; This study describes a sensitive microassay for measuring cytotoxicity based on the degree of inhibition of RNA synthesis in HepG2 cells. RNA synthesis is measured by the kinetic uptake of radiolabeled uridine. A large number of compounds were tested in a wide range of concentrations. The concentration required to induce 50% inhibition of HepG2 uridine uptake rates (IC50) was determined for each compound and used to rank its potency. These IC50s were compared with IC50s measured with the neutral red assay. 2-acetylaminofluorene, benzo[a]pyrene and methylnitrosourea were not cytotoxic in the neutral red assay. Uridine uptake was always inhibited at lower concentrations…
Interassay and interobserver comparability study of four programmed death-ligand 1 (PD-L1) immunohistochemistry assays in triple-negative breast canc…
2021
Different immunohistochemical programmed death-ligand 1 (PD-L1) assays and scorings have been reported to yield variable results in triple-negative breast cancer (TNBC). We compared the analytical concordance and reproducibility of four clinically relevant PD-L1 assays assessing immune cell (IC) score, tumor proportion score (TPS), and combined positive score (CPS) in TNBC. Primary TNBC resection specimens (n = 104) were stained for PD-L1 using VENTANA SP142, VENTANA SP263, DAKO 22C3, and DAKO 28–8. PD-L1 expression was scored according to guidelines on virtual whole slide images by four trained readers. The mean PD-L1 positivity at IC-score ≥1% and CPS ≥1 ranged between 53% and 75% with th…
Liquid biopsies in lung cancer: The new ambrosia of researchers
2014
Abstract: In the last decades the approach to cancer patient management has been deeply revolutionized. We are moving from a "one-fits-all" strategy to the "personalized medicine" based on the molecular characterization of the tumor. In this new era it is becoming more and more clear that the monitoring of the disease is fundamental for the success of the treatment, thus there is the need of new biomarker discovery. More precisely in the last years the scientific community has started to use the term "liquid biopsy". A liquid biopsy is a liquid biomarker that can be easily isolated from many body fluids (blood, saliva, urine, ascites, pleural effusion, etc.) and, as well as a tissue biopsy,…
Capturing colorectal cancer inter-tumor heterogeneity in patient-derived xenograft (PDX) models
2018
Patient-derived xenograft (PDX) models have become an important asset in translational cancer research. However, to provide a robust preclinical platform, PDXs need to accommodate the tumor heterogeneity that is observed in patients. Colorectal cancer (CRC) can be stratified into four consensus molecular subtypes (CMS) with distinct biological and clinical features. Surprisingly, using a set of CRC patients, we revealed the partial representation of tumor heterogeneity in PDX models. The epithelial subtypes, the largest subgroups of CRC subtype, were very ineffective in establishing PDXs, indicating the need for further optimization to develop an effective personalized therapeutic approach …