Search results for "Neoplasms"
showing 10 items of 7988 documents
CXCR7 Reactivates ERK Signaling to Promote Resistance to EGFR Kinase Inhibitors in NSCLC
2019
Abstract Although EGFR mutant–selective tyrosine kinase inhibitors (TKI) are clinically effective, acquired resistance can occur by reactivating ERK. We show using in vitro models of acquired EGFR TKI resistance with a mesenchymal phenotype that CXCR7, an atypical G protein-coupled receptor, activates the MAPK–ERK pathway via β-arrestin. Depletion of CXCR7 inhibited the MAPK pathway, significantly attenuated EGFR TKI resistance, and resulted in mesenchymal-to-epithelial transition. CXCR7 overexpression was essential in reactivation of ERK1/2 for the generation of EGFR TKI–resistant persister cells. Many patients with non–small cell lung cancer (NSCLC) harboring an EGFR kinase domain mutatio…
Noncanonical GLI1 signaling promotes stemness features and in vivo growth in lung adenocarcinoma
2016
Aberrant Hedgehog/GLI signaling has been implicated in a diverse spectrum of human cancers, but its role in lung adenocarcinoma (LAC) is still under debate. We show that the downstream effector of the Hedgehog pathway, GLI1, is expressed in 76% of LACs, but in roughly half of these tumors, the canonical pathway activator, Smoothened, is expressed at low levels, possibly owing to epigenetic silencing. In LAC cells including the cancer stem cell compartment, we show that GLI1 is activated noncanonically by MAPK/ERK signaling. Different mechanisms can trigger the MAPK/ERK/GLI1 cascade including KRAS mutation and stimulation of NRP2 by VEGF produced by the cancer cells themselves in an autocrin…
Autocrine CCL5 Effect Mediates Trastuzumab Resistance by ERK Pathway Activation in HER2-Positive Breast Cancer.
2020
Abstract HER2-positive breast cancer is currently managed with chemotherapy in combination with specific anti-HER2 therapies, including trastuzumab. However, a high percentage of patients with HER2-positive tumors do not respond to trastuzumab (primary resistance) or either recur (acquired resistance), mostly due to molecular alterations in the tumor that are either unknown or undetermined in clinical practice. Those alterations may cause the tumor to be refractory to treatment with trastuzumab, promoting tumor proliferation and metastasis. Using continued exposure of a HER2-positive cell line to trastuzumab, we generated a model of acquired resistance characterized by increased expression …
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…
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…
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…
Expanding the clinical spectrum of mosaic BRAF skin phenotypes
2021
BRAF postzygotic activating mutations have been found in 50% of cases of syringocystadenoma papilliferum (SCAP)1 and in phacomatosis pigmentokeratotica (PPK)2,3 , also possibly caused by HRAS4 mutations. BRAF is a RAS-activating serine/threonine kinase of the MAP kinase pathway, resulting in cell growth and proliferation. BRAF mutations, particularly p.(Val600Glu), are frequently identified in melanoma and other human cancers5 . We report clinical presentations of three patients with postzygotic BRAF mutations in affected skin, identified by next generation sequencing (NGS).
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…
Ellagitannin-rich cloudberry inhibits hepatocyte growth factorinduced cell migration and phosphatidylinositol 3-kinase/AKT activation in colon carcin…
2016
// Anne-Maria Pajari 1, 2 , Essi Paivarinta 1 , Lassi Paavolainen 3 , Elina Vaara 1 , Tuuli Koivumaki 4 , Ritu Garg 5 , Anu Heiman-Lindh 1 , Marja Mutanen 1 , Varpu Marjomaki 3 , Anne J. Ridley 2, 5 1 Department of Food and Environmental Sciences, Division of Nutrition, University of Helsinki, Helsinki, Finland 2 University College London, Ludwig Institute for Cancer Research, London, UK 3 Department of Biological and Environmental Science / Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland 4 Department of Food and Environmental Sciences, Division of Food Chemistry, University of Helsinki, Helsinki, Finland 5 Randall Division of Cell & Molecular Biophysics, King’s College Lond…