Search results for "Signal"
showing 10 items of 6924 documents
Nitric oxide: a new player in plant signalling and defence responses.
2004
There is increasing evidence that nitric oxide (NO), which was first identified as a unique diffusible molecular messenger in animals, plays important roles in diverse (patho)physiological processes in plants. NO functions include the modulation of hormonal, wounding and defence responses, as well as the regulation of cell death. Enzymes that catalyse NO synthesis and signalling cascades that mediate NO effects have recently been discovered, providing a better understanding of the mechanisms by which NO influences plant responses to various stimuli. Additionally, growing evidence suggests that NO signalling interacts with the salicylic acid and jasmonic acid signalling pathways.
Nuclear Translocation of Nuclear Transcription Factor-κB by α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptors Leads to Transcription of …
2003
We describe a new molecular mechanism of cell death by excitotoxicity mediated through nuclear transcription factor κB (NFκB) in rat embryonic cultures of dopaminergic neurons. Treatment of mesencephalic cultures with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) resulted in a number of changes that occurred selectively in dopaminergic neurons, including persistent elevation in intracellular Ca2+ monitored with Fura-2, and a significant increase in intramitochondrial oxidation of dihydrorhodamine 123, probably associated with transient increase of mitochondrial permeability, cytochrome c release, nuclear translocation of NFκB, and transcriptional activation of the oncogenep53.…
Chemically modified tetracyclines induce cytotoxic effects against J774 tumour cell line by activating the apoptotic pathway
2003
Here, we have studied the effects of chemically modified tetracyclines (CMTs) on apoptosis both at the level of the cytoplasmic proteolytic caspase cascade, and on Bcl-2 and c-myc mRNA expression in the J774 macrophage cell line. The results indicate that CMTs induce morphological changes consistent with apoptotic events, as clearly demonstrated both by the acridine orange and ethidium bromide staining, and by TUNEL and fragmentation ELISA assays. Furthermore, the analysis of the cell cycle by flow cytometry shows an evident apoptotic sub-G0G1 peak, without important modifications in the cell cycle distribution. CMTs induce programmed cell death (PCD) in a dose-dependent manner and CMT-8 is…
Cell fate regulation upon DNA damage : p53 Serine 46 kinases pave the cell death road
2019
Mild and massive DNA damage are differentially integrated into the cellular signaling networks and, in consequence, provoke different cell fate decisions. After mild damage, the tumor suppressor p53 directs the cellular response to cell cycle arrest, DNA repair, and cell survival, whereas upon severe damage, p53 drives the cell death response. One posttranslational modification of p53, phosphorylation at Serine 46, selectively occurs after severe DNA damage and is envisioned as a marker of the cell death response. However, the molecular mechanism of action of the p53 Ser46 phospho-isomer, the molecular timing of this phosphorylation event, and its activating effects on apoptosis and ferropt…
Cell death and hepatocarcinogenesis: Dysregulation of apoptosis signaling pathways
2011
Hepatocellular carcinoma (HCC) remains a disease with a poor prognosis despite recent advances in the pathophysiology and treatment. Although the disease is biologically heterogeneous, dysregulation of cellular proliferation and apoptosis both occur frequently and contribute to the malignant phenotype. Chronic liver disease is associated with intrahepatic inflammation which promotes dysregulation of cellular signaling pathways; this triggers proliferation and thus lays the ground for expansion of premalignant cells. Cancer emerges when immunological control fails and transformed cells develop resistance against cell death signaling pathways. The same mechanisms underlie the poor responsiven…
Heat shock proteins: essential proteins for apoptosis regulation
2008
Abstract Many different external and intrinsic apoptotic stimuli induce the accumulation in the cells of a set of proteins known as stress or heat shock proteins (HSPs). HSPs are conserved proteins present in both prokaryotes and eukaryotes. These proteins play an essential role as molecular chaperones by assisting the correct folding of nascent and stress-accumulated misfolded proteins, and by preventing their aggregation. HSPs have a protective function, that is they allow the cells to survive to otherwise lethal conditions. Various mechanisms have been proposed to account for the cytoprotective functions of HSPs. Several of these proteins have demonstrated to directly interact with compo…
Ferroptosis Meets Cell–Cell Contacts
2021
Ferroptosis is a regulated form of cell death characterized by iron dependency and increased lipid peroxidation. Initially assumed to be selectively induced in tumour cells, there is increasing evidence that ferroptosis plays an important role in pathophysiology and numerous cell types and tissues. Deregulated ferroptosis has been linked to human diseases, such as neurodegenerative diseases, cardiovascular disorders, and cancer. Along these lines, ferroptosis is a promising pathway to overcoming therapy resistance of cancer cells. It is therefore of utmost importance to understand the cellular signalling pathways and the molecular mechanisms underlying ferroptosis regulation, including cont…
Normalization of sphingomyelin levels by 2-hydroxyoleic acid induces autophagic cell death of SF767 cancer cells
2012
The very high mortality rate of gliomas reflects the unmet therapeutic need associated with this type of brain tumor. We have discovered that the plasma membrane fulfills a critical role in the propagation of tumorigenic signals, whereby changes in membrane lipid content can either activate or silence relevant pathways. We have designed a synthetic fatty acid, 2-hydroxyoleic acid (2OHOA), that specifically activates sphingomyelin synthase (SGMS), thereby modifying the lipid content of cancer cell membranes and restoring lipid levels to those found in normal cells. In reverting, the structure of the membrane by activating SGMS, 2OHOA inhibits the RAS-MAPK pathway, which in turn fails to acti…
Novel ways to sensitise gastrointestinal cancer to apoptosis.
2009
Gastrointestinal (GI) cancers are major health problems, being the most common cancers worldwide. Resistance to apoptosis is closely linked to carcinogenesis and enables malignant cells to evade therapy-induced cell death. In the recent past, the increasing understanding of molecular pathways of apoptosis has provided novel targets in cancer therapy. Several drugs, either inhibiting antiapoptotic signalling or actively inducing apoptosis in cancer cells, have already entered clinical trials. Until now, agents targeting apoptosis pathways are primarily being tested alone or in combination with chemotherapy. In the near future, personalized combination therapies will probably be beneficial fo…
Therapeutic targeting of apoptotic pathways in cancer.
2006
Programmed cell death (apoptosis) is a key tumor suppressor mechanism. Consequently, most if not all cancers develop mechanisms to abolish or circumvent this genetic program. Besides enabling malignant transformation and tumor progression, defects in apoptosis can result in resistance to cytotoxic cancer therapies. Much progress has been made in the delineation of the molecular pathways leading to apoptosis. This allows the identification of target molecules and lead compounds to develop novel therapies, which make use of this intrinsic death program for the treatment of cancer. Here, we review the current understanding of apoptotic signal transduction pathways, and strategies of their ther…