Search results for "Cell biology"

Myeloid Cell-Derived Reactive Oxygen Species Induce Epithelial Mutagenesis

2017

Increased oxidative stress has been suggested to initiate and promote tumorigenesis by inducing DNA damage and to suppress tumor development by triggering apoptosis and senescence. The contribution of individual cell types in the tumor microenvironment to these contrasting effects remains poorly understood. We provide evidence that during intestinal tumorigenesis, myeloid cell-derived H2O2 triggers genome-wide DNA mutations in intestinal epithelial cells to stimulate invasive growth. Moreover, increased reactive oxygen species (ROS) production in myeloid cells initiates tumor growth in various organs also in the absence of a carcinogen challenge in a paracrine manner. Our data identify an i…

Parthenolide and DMAPT exert cytotoxic effects on breast cancer stem-like cells by inducing oxidative stress, mitochondrial dysfunction and necrosis

2016

Triple-negative breast cancers (TNBCs) are aggressive forms of breast carcinoma associated with a high rate of recidivism. In this paper, we report the production of mammospheres from three lines of TNBC cells and demonstrate that both parthenolide (PN) and its soluble analog dimethylaminoparthenolide (DMAPT) suppressed this production and induced cytotoxic effects in breast cancer stem-like cells, derived from dissociation of mammospheres. In particular, the drugs exerted a remarkable inhibitory effect on viability of stem-like cells. Such an effect was suppressed by N-acetylcysteine, suggesting a role of reactive oxygen species (ROS) generation in the cytotoxic effect. Instead z-VAD, a ge…

Isolation, culture and analysis of adult subependymal neural stem cells

2016

Individual cells dissected from the subependymal neurogenic niche of the adult mouse brain proliferate in medium containing basic fibroblast growth factor (bFGF) and/or epidermal growth factor (EGF) as mitogens, to produce multipotent clonal aggregates called neurospheres. These cultures constitute a powerful tool for the study of neural stem cells (NSCs) provided that they allow the analysis of their features and potential capacity in a controlled environment that can be modulated and monitored more accurately than in vivo. Clonogenic and population analyses under mitogen addition or withdrawal allow the quantification of the self-renewing and multilineage potency of these cells and the id…

Stem-cell derived hepatocyte-like cells for the assessment of drug-induced liver injury.

2019

Drug-induced liver injury is a major cause of drug discovery failure in clinical trials and a leading cause of liver disease. Current preclinical drug testing does not predict hepatotoxicity which highlights the importance of developing highly predictive cell-based models. The use of stem cell technology and differentiation into hepatocyte-like cells (HLCs) could provide a stable source of hepatocytes for multiple applications, including drug screening. HLCs derived from both embryonic and induced pluripotent stem cells have been used to accurately predict hepatotoxicity as well as to test individual-specific toxicity. Although there are still many limitations, mainly related to the lack of…

Betulinic acid induces a novel cell death pathway that depends on cardiolipin modification

2016

Cancer is associated with strong changes in lipid metabolism. For instance, normal cells take up fatty acids (FAs) from the circulation, while tumour cells generate their own and become dependent on de novo FA synthesis, which could provide a vulnerability to target tumour cells. Betulinic acid (BetA) is a natural compound that selectively kills tumour cells through an ill-defined mechanism that is independent of BAX and BAK, but depends on mitochondrial permeability transition-pore opening. Here we unravel this pathway and show that BetA inhibits the activity of steroyl-CoA-desaturase (SCD-1). This enzyme is overexpressed in tumour cells and critically important for cells that utilize de n…

The secreted protein acidic and rich in cysteine is a critical mediator of cell death program induced by WIN/TRAIL combined treatment in osteosarcoma…

2015

Abstract Secreted protein acidic and rich in cysteine (SPARC) is a multi-functional protein which modulates cell-cell and cell-matrix interactions. In cancer cells, SPARC behaves as a tumor promoter in a number of tumors, but it can also act as a tumor suppressor factor. Our previous results showed that the synthetic cannabinoid WIN55,212-2 (WIN), a potent cannabinoid receptor agonist, is able to sensitize osteosarcoma MG63 cells to TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis which is accompanied with endoplasmic reticulum (ER)-stress induction and the increase in autophagic markers. In the present investigation, we studied the role of SPARC in WIN/TRAIL-induced apoptosi…

2017

AbstractPP2C serine–threonine phosphatase, Wip1, is an important regulator of stress response. Wip1 controls a number of critical cellular functions: proliferation, cell cycle arrest, senescence and programmed cell death, apoptosis or autophagy. Ppm1d, the gene encoding Wip1 phosphatase, is expressed in hematopoietic progenitors, stem cells, neutrophils, macrophages B and T lymphocytes in bone marrow and peripheral blood. The Wip1−/− mice display immunodeficiency, abnormal lymphoid histopathology in thymus and spleen, defects in B- and T-cell differentiation, as well as susceptibility to viral infection. At the same time, Wip1 knockout mice exhibit pro-inflammatory phenotype in skin and int…

Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells

2019

To fight resistances to radiotherapy, the understanding of escape mechanisms of tumor cells is crucial. The aim of this study was to identify phosphoproteins that are regulated upon irradiation. The comparative analysis of the phosphoproteome before and after irradiation brought nucleophosmin (NPM1) into focus as a versatile phosphoprotein that has already been associated with tumorigenesis. We could show that knockdown of NPM1 significantly reduces tumor cell survival after irradiation. NPM1 is dephosphorylated stepwise within 1 hour after irradiation at two of its major phosphorylation sites: threonine-199 and threonine-234/237. This dephosphorylation is not the result of a fast cell cycl…

Molecular Engineering Strategies Tailoring the Apoptotic Response to a MET Therapeutic Antibody

2020

The MET oncogene encodes a tyrosine kinase receptor involved in the control of a complex network of biological responses that include protection from apoptosis and stimulation of cell growth during embryogenesis, tissue regeneration, and cancer progression. We previously developed an antagonist antibody (DN30) inducing the physical removal of the receptor from the cell surface and resulting in suppression of the biological responses to MET. In its bivalent form, the antibody displayed a residual agonist activity, due to dimerization of the lingering receptors, and partial activation of the downstream signaling cascade. The balance between the two opposing activities is variable in different…

Yeast Cth2 protein represses the translation of ARE-containing mRNAs in response to iron deficiency

2018

In response to iron deficiency, the budding yeast Saccharomyces cerevisiae undergoes a metabolic remodeling in order to optimize iron utilization. The tandem zinc finger (TZF)-containing protein Cth2 plays a critical role in this adaptation by binding and promoting the degradation of multiple mRNAs that contain AU-rich elements (AREs). Here, we demonstrate that Cth2 also functions as a translational repressor of its target mRNAs. By complementary approaches, we demonstrate that Cth2 protein inhibits the translation of SDH4, which encodes a subunit of succinate dehydrogenase, and CTH2 mRNAs in response to iron depletion. Both the AREs within SDH4 and CTH2 transcripts, and the Cth2 TZF are es…