Search results for "HDAC"

The histone deacetylase Rpd3 regulates the heterochromatin structure of Drosophila telomeres

2011

Telomeres are specialized structures at the end of eukaryotic chromosomes that are required to preserve genome integrity, chromosome stability and nuclear architecture. Telomere maintenance and function are established epigenetically in several eukaryotes. However, the exact chromatin enzymatic modifications regulating telomere homeostasis are poorly understood. In Drosophila melanogaster, telomere length and stability are maintained through the retrotransposition of specialized telomeric sequences and by the specific loading of protecting capping proteins, respectively. Here, we show that the loss of the essential and evolutionarily conserved histone deacetylase Rpd3, the homolog of mammal…

JNK phosphorylation relieves HDAC3-dependent suppression of the transcriptional activity of c-Jun

2003

The AP-1 transcription factor c-Jun is a prototypical nuclear effector of the JNK signal transduction pathway. The integrity of JNK phosphorylation sites at serines 63/73 and at threonines 91/93 in c-Jun is essential for signal-dependent target gene activation. We show that c-Jun phosphorylation mediates dissociation of an inhibitory complex, which is associated with histone deacetylase 3 (HDAC3). The subsequent events that ultimately cause increased mRNA synthesis are independent of c-Jun phosphorylation and its interaction with JNK. These findings provide an 'activation by de-repression' model as an explanation for the stimulatory function of JNK on c-Jun.

Generation and characterization of tTS-H4: a novel transcriptional repressor that is compatible with the reverse tetracycline-controlled TET-ON system

2007

Background Conditional gene regulatory systems ensuring tight and adjustable expression of therapeutic genes are central for developing future gene therapy strategies. Among various regulatory systems, tetracycline-controlled gene expression has emerged as a safe and reliable option. Moreover, the tightness of tetracycline-regulated gene switches can be substantially improved by complementing transcriptional activators with antagonizing repressors. Methods To develop novel tetracycline-responsive transcriptional repressors, we fused various transcriptional silencing domains to the TetR (B/E) DNA-binding and dimerization domain of the Tn10-encoded tetracycline resistance operon (TetR (B/E)).…

Tributyltin(Iv) butyrate: A novel epigenetic modifier with er stress-and apoptosis-inducing properties in colon cancer cells

2021

Organotin(IV) compounds are a class of non-platinum metallo-conjugates exhibiting antitumor activity. The effects of different organotin types has been related to several mechanisms, including their ability to modify acetylation protein status and to promote apoptosis. Here, we focus on triorganotin(IV) complexes of butyric acid, a well-known HDAC inhibitor with antitumor properties. The conjugated compounds were synthesized and characterised by FTIR spectroscopy, multi-nuclear (1H, 13C and 119Sn) NMR, and mass spectrometry (ESI-MS). In the triorganotin(IV) complexes, an anionic monodentate butyrate ligand was observed, which coordinated the tin atom on a tetra-coordinated, monomeric enviro…

Les histones désacétylases de type 2 (HD2) : caractérisation fonctionnelle dans l'immunité des plantes

2016

Les histones désacétylases (HDAC) sont des enzymes qui catalysent les réactions de désacétylation des protéines, une modification post-traductionnelle caractérisée par le retrait d’un groupement acétyle des chaînes latérales des résidus de lysine des protéines. Chez les plantes, il existe trois familles de HDAC. Les deux premières – les familles RDP3/HDA1 et SIR2 – sont communes à tous les eucaryotes, alors que la troisième – la famille des HD2 – est spécifique des plantes. Chez le tabac, des HD2 ont été identifiées comme des régulateurs négatifs de la réponse hypersensible induite par la cryptogéine, un éliciteur protéique. La réponse hypersensible est une réponse de défense caractérisée p…

The Histone Deacetylase Inhibitor ITF2357 (Givinostat) Targets Oncogenic BRAF in Melanoma Cells and Promotes a Switch from Pro-Survival Autophagy to …

2022

Histone deacetylase inhibitors (HDACI) are epigenetic compounds that have been widely considered very promising antitumor agents. Here, we focus on the effects of the pan-HDAC inhibitor ITF2357 (Givinostat) in comparison with SAHA (Vorinostat) in melanoma cells bearing BRAF V600E oncogenic mutation. Our results indicate both ITF2357 and SAHA dose-dependently reduce the viability of BRAF-mutated SK-MEL-28 and A375 melanoma cells. The comparison of IC50 values revealed that ITF2357 was much more effective than SAHA. Interestingly, both inhibitors markedly decreased oncogenic BRAF protein expression levels, ITF2357 being the most effective compound. Moreover, the BRAF decrease induced by ITF23…

Carbocysteine reverses the effects of cigarette smoke and improves the effects of beclomethasone on the histone deacetylases in bronchial epithelial …

2015

Cigarette smoke exposure, increasing oxidative stress, may negatively affect histone deacetylase expression/activity. Histone deacetylase expression/activity and in particular HDAC2, HDAC3, and SIRT-1 may control inflammation, cell senescence and responses to corticosteroids. The effects of carbocysteine and of beclomethasone on the histone deacetylase expression/activity in human bronchial epithelial cells stimulated with cigarette smoke extracts (CSE) are largely unknown. This study was aimed to explore whether carbocysteine and beclomethasone, in a bronchial epithelial cell line (16-HBE) exposed to CSE, were able to modulate the expression/activity of HDAC2, HDAC3, and of SIRT-1. Methods…

Possible mechanisms of Raf-1 Kinase Inhibitor Protein down-regulation in hepatocellular carcinoma

2011

Induction of Apoptosis and Chemosensitization by the Histone Deacetylase Inhibitor Trichostatin in Hepatocellular Carcinoma Cells: Molecular Analysis…

2011

The mRNA and protein levels of RKIP are reduced and those of YY1 increased in clinical HCC. Loss, mutation, or promoter hypermethylation of the RKIP gene may not account for the downregulation of RKIP in HCC. Histone deacetylation can silence gene expression and play a significant role in hepatocarcinogenesis. The histone deacetylase inhibitor (HDACI) trichostatin induced cell growth inhibition and proapoptotic effects in HA22T/VGH and HepG2 HCC cells; it also exhibited synergy with doxorubicin. Treatment with trichostatin caused histone hyperacetylation and down- or upregulated expression of different genes (such as β-catenin, cyclin D1, hTERT, XIAP, and IL-6). These changes might, at leas…

THE HDAC INHIBITOR ITF2357 (GIVINOSTAT) AS A KEY PLAYER IN EPIGENETIC TARGETING OF MELANOMA AND COLON CANCER CELLS

2023

Histone deacetylase inhibitors (HDACIs) are epigenetic compounds that have been recently considered for their promising anti-tumor activity. The aim of this PhD thesis was to elucidate and characterize the anti-tumor effect of the HDAC inhibitor ITF2357 (Givinostat) in melanoma and colon cancer cells that are characterized by oncogenic BRAF mutations. Interestingly, data reported in this thesis demonstrate that ITF2357 exerts a remarkable anti-tumor effect in melanoma cells by inducing a switch from a pro-survival autophagy to caspase-dependent apoptosis. The thesis provides the first evidences that ITF2357 is able to target oncogenic BRAF and oncogenic p53. The ITF2357 decreasing effect on…