Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA137503 | ENA |
REPOSITORIES: ENA
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Project description:Epigenetic modifying enzymes are commonly mutated in diffuse large B cell lymphoma (DLBCL), suggesting that epigenetic regulation is an important factor in DLBCL pathogenesis and a potential target for therapy. We developed resistant cell lines to histone deacetylase inhibitors (HDACi), one such epigenetic therapy, in order to define mechanisms of response and resistance. Strikingly, using gene expression and metabolic profiling, we found that development of HDACi resistance was associated with differentiation toward a plasmablast-like phenotype. Differentiation correlated with decreased B cell receptor signaling, increased ER stress and activation of the unfolded protein response, and increased sensitivity to proteasome inhibitors. Importantly, we found evidence of differentiation in lymphoma biopsies from patients treated with HDACi. Together, these data show, for the first time, that HDACi are differentiating agents in lymphoma and may be used to prime DLBCL for targeted therapy including proteasome inhibitors. Gene expression in DLBCL cells from tumor biopsies after 15 days panobinostat therapy
2016-08-01 | E-GEOD-59308 | biostudies-arrayexpress
Project description:Epigenetic modifying enzymes are commonly mutated in diffuse large B cell lymphoma (DLBCL). Importantly, genetics abnormalities lead to inactivation of HAT, which tilt the balance in favor of decreased protein acetylation in DLBCL cells. This suggests that protein acetylation regulation is an important factor in DLBCL pathogenesis and a potential target for therapy. We developed resistant cell lines to the histone deacetylase inhibitor (HDACi) vorinostat, in order to better define molecular mechanisms of action of HDACi in lymphoma cells. We found that cells resistant to HDACi have increased protein synthesis and proteasomal degradation. Additionally, cells resistant to HDACi have acquired increased susceptibility to proteasome inhibitors and this correlates with activation of the unfolded protein response. Importantly, using transcriptional signatures found in our resistant lymphoma cell line model, we show that tumors from DLBCL patients treated but unresponsive to HDACi therapy undergo similar changes. Together, these data show, for the first time, that HDACi may be used to prime DLBCL for targeted therapy including proteasome inhibitors. Gene expression in U937 cells after 12h exposure to 2µM vorinostat and after development of resistance to 2 µM vorinostat, with and without vorinostat in the media.
2016-06-01 | E-GEOD-58421 | biostudies-arrayexpress
Project description:Epigenetic modifying enzymes are commonly mutated in diffuse large B cell lymphoma (DLBCL). Importantly, genetics abnormalities lead to inactivation of HAT, which tilt the balance in favor of decreased protein acetylation in DLBCL cells. This suggests that protein acetylation regulation is an important factor in DLBCL pathogenesis and a potential target for therapy. We developed resistant cell lines to the histone deacetylase inhibitor (HDACi) vorinostat, in order to better define molecular mechanisms of action of HDACi in lymphoma cells. We found that cells resistant to HDACi have increased protein synthesis and proteasomal degradation. Additionally, cells resistant to HDACi have acquired increased susceptibility to proteasome inhibitors and this correlates with activation of the unfolded protein response. Importantly, using transcriptional signatures found in our resistant lymphoma cell line model, we show that tumors from DLBCL patients treated but unresponsive to HDACi therapy undergo similar changes. Together, these data show, for the first time, that HDACi may be used to prime DLBCL for targeted therapy including proteasome inhibitors.
2016-06-01 | GSE58421 | GEO
Project description:Epigenetic modifying enzymes are commonly mutated in diffuse large B cell lymphoma (DLBCL), suggesting that epigenetic regulation is an important factor in DLBCL pathogenesis and a potential target for therapy. We developed resistant cell lines to histone deacetylase inhibitors (HDACi), one such epigenetic therapy, in order to define mechanisms of response and resistance. Strikingly, using gene expression and metabolic profiling, we found that development of HDACi resistance was associated with differentiation toward a plasmablast-like phenotype. Differentiation correlated with decreased B cell receptor signaling, increased ER stress and activation of the unfolded protein response, and increased sensitivity to proteasome inhibitors. Importantly, we found evidence of differentiation in lymphoma biopsies from patients treated with HDACi. Together, these data show, for the first time, that HDACi are differentiating agents in lymphoma and may be used to prime DLBCL for targeted therapy including proteasome inhibitors.
2016-08-01 | GSE59308 | GEO
Project description:DNA-hypomethylating agents approved for older AML patients, are clinically tested in combination with histone deacetylase inhibitors (HDACi).The mechanism of action of these drugs is still under debate. In colon cancer cells, 5-aza-2'deoxycytidine (DAC) can downregulate oncogenes and metabolic genes by reversing gene body DNA methylation, thus implicating gene body methylation as a novel drug target. We asked whether DAC-induced gene body demethylation in AML cells is also associated with gene repression, and whether the latter is enhanced by HDACi. Transcriptome analyses revealed that a combined treatment with DAC and HDACi panobinostat or valproic acid effected significantly more transcripts than the sum of the genes regulated by either treatment alone, demonstrating a quantitative synergistic effect on genome-wide expression in U937 cells. This effect was particularly striking for downregulated genes. Integrative analysis of the methylome and transcriptome showed that a massive downregulation of genes, including oncogenes (e.g.c-MYC) and epigenetic modifiers (e.g. KDM2B and SUV39H1) often overexpressed in cancer, was associated predominantly with gene body DNA demethylation, and changes in acH3K9/27. These findings have implications for the mechanism of action of combined epigenetic treatment, and for a better understanding of responses in trials where this approach is clinically tested.
2018-03-02 | GSE111293 | GEO
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
| S-EPMC2531291 | biostudies-literature
Project description:RNA extracted at 240min. Samples are rRNA depleted. Expression measurement of Homo sapiens genes.
2019-07-31 | GSE114179 | GEO
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
| S-EPMC4686780 | biostudies-literature
Project description:PurposeWe investigated the evidence of recent positive selection in the human phototransduction system at single nucleotide polymorphism (SNP) and gene level.MethodsSNP genotyping data from the International HapMap Project for European, Eastern Asian, and African populations was used to discover differences in haplotype length and allele frequency between these populations. Numeric selection metrics were computed for each SNP and aggregated into gene-level metrics to measure evidence of recent positive selection. The level of recent positive selection in phototransduction genes was evaluated and compared to a set of genes shown previously to be under recent selection, and a set of highly conserved genes as positive and negative controls, respectively.ResultsSix of 20 phototransduction genes evaluated had gene-level selection metrics above the 90th percentile: RGS9, GNB1, RHO, PDE6G, GNAT1, and SLC24A1. The selection signal across these genes was found to be of similar magnitude to the positive control genes and much greater than the negative control genes.ConclusionsThere is evidence for selective pressure in the genes involved in retinal phototransduction, and traces of this selective pressure can be demonstrated using SNP-level and gene-level metrics of allelic variation. We hypothesize that the selective pressure on these genes was related to their role in low light vision and retinal adaptation to ambient light changes. Uncovering the underlying genetics of evolutionary adaptations in phototransduction not only allows greater understanding of vision and visual diseases, but also the development of patient-specific diagnostic and intervention strategies.
| S-EPMC3743458 | biostudies-literature
Project description:Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoid neoplasm in the world representing 30-40% of all lymphomas. Standard immunochemotherapy (cyclophosphamide, doxorubicin, vincristine, prednisone and rituximab) ensures cure in 60 to 65% of patients, while the rest progress or relapse. While advances have been made in the treatment of DLBCL, especially with the addition of rituximab, it is now apparent that there may be significant differences in prognosis that are related to the cell of origin, and that this disease is heterogeneous and novel treatment options are needed. It has been hypothesized that the combination of HDACI and hypomethylating agents might be a new approach to the treatment of relapsed or refractory DLBCL. This combination is thought to disrupt the transcription repressor complex consisting of methyl binding domain proteins (MBDP) and histone deacetylases (HDACs). We have explored the effect of different HDACI and decitabine combinations in in vitro and in vivo models of DLBCL. These data suggest a class effect, with all four HDACI (panobinostat, belinostat, vorinostat, depsipeptide) synergizing with decitabine in cytotoxicity assay across the spectrum of DLBCL cells. Synergy was validated in a number of other assays including a caspase 3 activation and apoptosis. Furthermore, the combination of panobinostat and decitabine induced markedly increased histone acetylation. The in vitro observations were confirmed in an in vivo murine xenograft experiment with the Ly1 DLBCL line. Genome wide methylation analysis and gene expression profiling demonstrated that the combination of these two epigenetic therapies produced a unique gene expression profile compared to the samples treated with single drugs. These data strongly support the potential therapeutic role of a combinatorial epigenetic platform for the treatment of B-cell lymphomas, in particular in patients with DLBCL. Clearly, future studies will need to focus on integrating the appropriate correlative studies, with an effort to identify and or validate biomarkers of activity with these combinations. The likelihood moving forward is that the mechanism of action of these combinations may vary from disease context to disease context. Genome-wide array findings from these kinds of studies could be expanded to samples from patients on clinical trials to identify novel biomarkers of response, leading to the rational treatment of individual diseases based upon the underlying pathogenesis. We have used single samples from three DLBCL cell lines (biological replicates) which were treated with DMSO, decitabine alone, panobinostat alone and their combination for 48h - total of 12 samples
2011-02-15 | E-GEOD-27226 | biostudies-arrayexpress