Search results for "glycoproteins"
showing 10 items of 496 documents
The CD95/CD95 ligand system is not the major effector in anticancer drug-mediated apoptosis.
1998
Many anticancer drugs are able to induce apoptosis in tumor cells but the mechanisms underlying this phenomenon are poorly understood. Some authors reported that the p53 tumor suppressor gene may be responsible for drug-induced apoptosis; however, chemotherapy-induced apoptosis can also be observed in p53 negative cells. Recently, doxorubicin (DXR) was reported to induce CD95L expression to mediate apoptosis through the CD95/CD95L system. Thus, an impairment of such a system may be involved in drug resistance. We evaluated the in vitro antitumor activity of several cytotoxic drugs on two human p53-negative T-cell lymphoma cell lines, the HUT78-B1 CD95L-resistant cell line and the HUT78 pare…
Defective apoptosis and tumorigenesis: role of p53 mutation and Fas/FasL system dysregulation
2010
The transcription factor p53 and the cytokine receptor FasL are two of the most famous regulators of cell life, and their alterations can cause a large number of pathologies, including cancer. In this review, we focused on how they can determine defective apoptosis, one of the causes of tumorigenesis and tumor progression. The importance of this knowledge lies in the new perspectives that gene therapy can offer to cure cancer.
The cyclopentenone-type prostaglandin 15-deoxy-delta12,14-prostaglandin J2 inhibits CD95 ligand gene expression in T lymphocytes: interference with p…
2003
Abstract 15-Deoxy-Δ12,14-PGJ2 (15d-PGJ2) is a cyclopentenone-type PG endowed with anti-inflammatory properties and produced by different cells, including those of the immune system. 15d-PGJ2 is a natural ligand of the peroxisome proliferator-activated receptor (PPAR)-γ nuclear receptor, but relevant PPARγ-independent actions mediated by this prostanoid have been described. Fas (APO-1/CD95) and its ligand (Fas-L) are cell surface proteins whose interaction activates apoptosis of Fas-expressing targets. In T cells, the Fas-Fas-L system regulates activation-induced cell death and has been implicated in diseases in which lymphocyte homeostasis is compromised. Moreover, several studies have desc…
In Candida parapsilosis the ATC1 Gene Encodes for an Acid Trehalase Involved in Trehalose Hydrolysis, Stress Resistance and Virulence
2014
An ORF named CPAR2-208980 on contig 005809 was identified by screening a Candida parapsilosis genome data base. Its 67% identity with the acid trehalase sequence from C. albicans (ATC1) led us to designate it CpATC1. Homozygous mutants that lack acid trehalase activity were constructed by gene disruption at the two CpATC1 chromosomal alleles. Phenotypic characterization showed that atc1Δ null cells were unable to grow on exogenous trehalose as carbon source, and also displayed higher resistance to environmental challenges, such as saline exposure (1.2 M NaCl), heat shock (42°C) and both mild and severe oxidative stress (5 and 50 mM H2O2). Significant amounts of intracellular trehalose were …
Changes in the cell wall glycoprotein composition of Candida albicans associated to the inhibition of germ tube formation by EDTA.
1994
Hyphal development in Candida albicans was blocked by EDTA. This effect was not due to a general growth inhibition since the chelator did not affect protein and DNA synthesis. Recovery of mycelial growth was observed when EDTA-grown cells were incubated at 37 degrees C in EDTA-free medium. High-molecular-weight mannoproteins (HMWM) that are mycelium-specific wall components, and particularly a 260-kDa species (HMWM-260), were absent in the wall of cells grown under germination conditions in the presence of EDTA. Synthesis of the HMWM-260 species was not inhibited but its incorporation (secretion) into the wall structure seemed to be blocked in EDTA-treated cells.
CD133 Expression Is Not Synonymous to Immunoreactivity for AC133 and Fluctuates throughout the Cell Cycle in Glioma Stem-Like Cells.
2015
A transmembrane protein CD133 has been implicated as a marker of stem-like glioma cells and predictor for therapeutic response in malignant brain tumours. CD133 expression is commonly evaluated by using antibodies specific for the AC133 epitope located in one of the extracellular domains of membrane-bound CD133. There is conflicting evidence regarding the significance of the AC133 epitope as a marker for identifying stem-like glioma cells and predicting the degree of malignancy in glioma cells. The reasons for discrepant results between different studies addressing the role of CD133/AC133 in gliomas are unclear. A possible source for controversies about CD133/AC133 is the widespread assumpt…
Urokinase Plasminogen Activator and Gelatinases Are Associated with Membrane Vesicles Shed by Human HT1080 Fibrosarcoma Cells
1997
Membrane vesicles are shed by tumor cells both in vivo and in vitro. Although their functions are not well understood, it has been proposed that they may play multiple roles in tumor progression. We characterized membrane vesicles from human HT1080 fibrosarcoma cell cultures for the presence of proteinases involved in tumor invasion. By gelatin zymography and Western blotting, these vesicles showed major bands corresponding to the zymogen and active forms of gelatinase B (MMP-9) and gelatinase A (MMP-2) and to the MMP-9. tissue inhibitor of metalloproteinase 1 complex. Both gelatinases appeared to be associated with the vesicle membrane. HT1080 cell vesicles also showed a strong, plasminoge…
Sorting of a secretory protein (gp80) to the apical surface of Caco-2 cells
1994
We have investigated the synthesis and polarized secretion of the exogenous gp80 glycoprotein complex in the human epithelial adenocarcinoma cell line, Caco-2. gp80 is secreted at the apical surface of Madin-Darby canine kidney (MDCK) cells and should, therefore, display the signal(s) required for sorting into the apical exocytic pathway. In Caco-2 cells, no bona fide secretory protein released preferentially at the apical surface has been described so far. To address the question of whether Caco-2 cells possess a machinery capable of delivery of secretory proteins at the apical surface, we stably transfected the cells with a recombinant gene coding for the gp80 glycoprotein complex. Pulse-…
β1-Integrin Cytoplasmic Subdomains Involved in Dominant Negative Function
1998
The beta1-integrin cytoplasmic domain consists of a membrane proximal subdomain common to the four known isoforms ("common" region) and a distal subdomain specific for each isoform ("variable" region). To investigate in detail the role of these subdomains in integrin-dependent cellular functions, we used beta1A and beta1B isoforms as well as four mutants lacking the entire cytoplasmic domain (beta1TR), the variable region (beta1COM), or the common region (beta1 deltaCOM-B and beta1 deltaCOM-A). By expressing these constructs in Chinese hamster ovary and beta1 integrin-deficient GD25 cells (Wennerberg et al., J Cell Biol 132, 227-238, 1996), we show that beta1B, beta1COM, beta1 deltaCOM-B, a…
Lrp4, a Novel Receptor for Dickkopf 1 and Sclerostin, Is Expressed by Osteoblasts and Regulates Bone Growth and Turnover In Vivo
2009
Lrp4 is a multifunctional member of the low density lipoprotein-receptor gene family and a modulator of extracellular cell signaling pathways in development. For example, Lrp4 binds Wise, a secreted Wnt modulator and BMP antagonist. Lrp4 shares structural elements within the extracellular ligand binding domain with Lrp5 and Lrp6, two established Wnt co-receptors with important roles in osteogenesis. Sclerostin is a potent osteocyte secreted inhibitor of bone formation that directly binds Lrp5 and Lrp6 and modulates both BMP and Wnt signaling. The anti-osteogenic effect of sclerostin is thought to be mediated mainly by inhibition of Wnt signaling through Lrp5/6 within osteoblasts. Dickkopf1 …