Search results for "Signal Transduction"
showing 10 items of 2020 documents
RAS/RAF/MEK/ERK, PI3K/PTEN/AKT/mTORC1 and TP53 pathways and regulatory miRs as therapeutic targets in hepatocellular carcinoma
2019
Introduction: Hepatocellular carcinoma (HCC) is a significant problem globally because of viral infections and the increasing incidence of obesity and fatty liver disease. However, it is difficult to treat because its inherent genetic heterogeneity results in activation of numerous signaling pathways. Kinases have been targeted for decades with varying results, but the development of therapeutic resistance is a major challenge. Areas covered: The key roles of the RAS/RAF/MEK/ERK, PI3K/PTEN/AKT/mTORC1, TP53 microRNAs (miRs) as therapeutic targets are discussed and we suggests novel approaches for targeting miRs or their downstream targets to combat HCC. We performed literature searches using…
Uncovering the Signaling Pathway behind Extracellular Guanine-Induced Activation of NO System: New Perspectives in Memory-Related Disorders
2018
Mounting evidence suggests that the guanine-based purines stand out as key player in cell metabolism and in several models of neurodegenerative disorders, such as Parkinson's and Alzheimer's diseases. Guanosine (GUO) and guanine (GUA) are extracellular signaling molecules derived from the breakdown of the correspondent nucleotide, GTP, and their intracellular and extracellular levels are regulated by the fine-tuned activity of two major enzymes, purine nucleoside phosphorylase (PNP) and guanine deaminase (GDA). Noteworthy, GUO and GUA, seem to play opposite roles in the modulation of cognitive functions, such as learning and memory. Indeed GUO, despite exerting neuroprotective, anti-apoptot…
Therapeutic resistance in breast cancer cells can result from deregulated EGFR signaling
2020
The epidermal growth factor receptor (EGFR) interacts with various downstream molecules including phospholipase C (PLC)/protein kinase C (PKC), Ras/Raf/MEK/ERK, PI3K/PTEN/Akt/GSK-3, Jak/STAT and others. Often these pathways are deregulated in human malignancies such as breast cancer. Various therapeutic approaches to inhibit the activity of EGFR family members including small molecule inhibitors and monoclonal antibodies (MoAb) have been developed. A common problem with cancer treatments is the development of drug-resistance. We examined the effects of a conditionally-activated EGFR (v-Erb-B:ER) on the resistance of breast cancer cells to commonly used chemotherapeutic drugs such as doxorub…
ERK3/MAPK6 controls IL-8 production and chemotaxis
2020
ERK3 is a ubiquitously expressed member of the atypical mitogen activated protein kinases (MAPKs) and the physiological significance of its short half-life remains unclear. By employing gastrointestinal 3D organoids, we detect that ERK3 protein levels steadily decrease during epithelial differentiation. ERK3 is not required for 3D growth of human gastric epithelium. However, ERK3 is stabilized and activated in tumorigenic cells, but deteriorates over time in primary cells in response to lipopolysaccharide (LPS). ERK3 is necessary for production of several cellular factors including interleukin-8 (IL-8), in both, normal and tumorigenic cells. Particularly, ERK3 is critical for AP-1 signaling…
Targeting prohibitins at the cell surface prevents Th17-mediated autoimmunity.
2018
T helper (Th)17 cells represent a unique subset of CD4(+) T cells and are vital for clearance of extracellular pathogens including bacteria and fungi. However, Th17 cells are also involved in orchestrating autoimmunity. By employing quantitative surface proteomics, we found that the evolutionarily conserved prohibitins (PHB1/2) are highly expressed on the surface of both murine and human Th17 cells. Increased expression of PHBs at the cell surface contributed to enhanced CRAF/MAPK activation in Th17 cells. Targeting surface‐expressed PHBs on Th17 cells with ligands such as Vi polysaccharide (Typhim vaccine) inhibited CRAF‐MAPK pathway, reduced interleukin (IL)‐17 expression and ameliorated …
A PTEN inhibitor displays preclinical activity against hepatocarcinoma cells
2016
Phosphatase and tensin homolog (PTEN) gene is considered a tumor suppressor gene. However, PTEN mutations rarely occur in hepatocellular carcinoma (HCC), whereas heterozygosity of PTEN, resulting in reduced PTEN expression, has been observed in 32–44% of HCC patients. In the present study, we investigated the effects of the small molecule PTEN inhibitor VO-OHpic in HCC cells. VO-OHpic inhibited cell viability, cell proliferation and colony formation, and induced senescence-associated β-galactosidase activity in Hep3B (low PTEN expression) and to a lesser extent in PLC/PRF/5 (high PTEN expression) cells, but not in PTEN-negative SNU475 cells. VO-OHpic synergistically inhibited cell viability…
Effects of mutations in Wnt/β-catenin, hedgehog, Notch and PI3K pathways on GSK-3 activity—Diverse effects on cell growth, metabolism and cancer
2016
Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase that participates in an array of critical cellular processes. GSK-3 was first characterized as an enzyme that phosphorylated and inactivated glycogen synthase. However, subsequent studies have revealed that this moon-lighting protein is involved in numerous signaling pathways that regulate not only metabolism but also have roles in: apoptosis, cell cycle progression, cell renewal, differentiation, embryogenesis, migration, regulation of gene transcription, stem cell biology and survival. In this review, we will discuss the roles that GSK-3 plays in various diseases as well as how this pivotal kinase interacts with multiple sign…
Targeting Angiogenesis in Biliary Tract Cancers: An Open Option
2017
Abstract: Biliary tract cancers (BTCs) are characterized by a bad prognosis and the armamentarium of drugs for their treatment is very poor. Although the inflammatory status of biliary tract represents the first step in the cancerogenesis, the microenvironment also plays a key role in the pathogenesis of BTCs, promoting tumor angiogenesis, invasion and metastasis. Several molecules, such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF), are involved in the angiogenesis process and their expression on tumor samples has been explored as prognostic marker in both cholangiocarcinoma and gallbladder cancer. Recent studies evaluated the genomic landscape of BTCs and…
Nuclear signaling of plant MAPKs
2018
This article is part of the research topic: Post-Translational Modifications in Plant Nuclear Signaling: Novel Insights into Responses to Environmental Changes; International audience; Mitogen-activated protein kinases (MAPKs) are conserved protein kinases in eukaryotes that establish signaling modules where MAPK kinase kinases (MAPKKKs) activate MAPK kinases (MAPKKs) which in turn activate MAPKs. In plants, they are involved in the signaling of multiple environmental stresses and developmental programs. MAPKs phosphorylate their substrates and this post-translational modification (PTM) contributes to the regulation of proteins. PTMs may indeed modify the activity, subcellular localization,…
Cellular complexity in MAPK signaling in plants: Questions and emerging tools to answer them
2018
International audience; Mitogen activated protein kinase (MAPK) cascades play an important role in many aspects of plant growth, development, and environmental response. Because of their central role in many important processes, MAPKs have been extensively studied using biochemical and genetic approaches. This work has allowed for the identification of the MAPK genes and proteins involved in a number of different signaling pathways. Less well developed, however, is our understanding of how MAPK cascades and their corresponding signaling pathways are organized at subcellular levels. In this review, we will provide an overview of plant MAPK signaling, including a discussion of what is known a…