0000000001107780
AUTHOR
Juan Sandoval
showing 31 related works from this author
A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer patients
2019
Background Pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) in triple-negative breast cancer (TNBC) varies between 30 and 40% approximately. To provide further insight into the prediction of pCR, we evaluated the role of an epigenetic methylation-based signature. Methods Epigenetic assessment of DNA extracted from biopsy archived samples previous to NAC from TNBC patients was performed. Patients included were categorized according to previous response to NAC in responder (pCR or residual cancer burden, RCB = 0) or non-responder (non-pCR or RCB > 0) patients. A methyloma study was performed in a discovery cohort by the Infinium HumanMethylation450 BeadChip (450K arra…
Identification of a gene-pathway associated with non-alcoholic steatohepatitis.
2007
Background/Aims We have integrated gene expression profiling of liver biopsies of NASH patients with liver samples of a mouse model of steatohepatitis (MAT1A-KO) to identify a gene-pathway associated with NASH. Methods Affymetrix U133 Plus 2.0 microarrays were used to evaluate nine patients with NASH, six patients with steatosis, and six control subjects; Affymetrix MOE430A microarrays were used to evaluate wild-type and MAT1A-KO mice at 15 days, 1, 3, 5 and 8 months after birth. Transcriptional profiles of patients with NASH and MAT1A-KO mice were compared with those of their proficient controls. Results We identified a gene-pathway associated with NASH, that accurately distinguishes betwe…
Interaction Between Cytokines and Oxidative Stress in Acute Pancreatitis
2006
Acute pancreatitis is an inflammation initially localized in the pancreatic gland which may lead to local and systemic complications. The development of severe acute pancreatitis is mediated by pathophysiological mechanisms involved in the systemic inflammatory response, cytokines and oxidative stress being their components of major importance. Nevertheless, it is still unknown why an episode of acute pancreatitis remains mild or progresses to a severe form. Activated leukocytes are the main source of cytokines. Interleukin 1beta and tumor necrosis factor alpha (TNF-alpha) initiate and propagate almost all the consequences of the systemic inflammatory response syndrome, leading to amplifica…
Nitric oxide triggers mammary gland involution after weaning: remodelling is delayed but not impaired in mice lacking inducible nitric oxide synthase
2010
During mammary gland involution, different signals are required for apoptosis and tissue remodelling. To explore the role of NO in the involution of mammary tissue after lactation, NOS2 (inducible nitric oxide synthase)-KO (knockout) mice were used. No apparent differences were observed between NOS2-KO and WT (wild-type) animals during pregnancy and lactation. However, upon cessation of lactation, a notable delay in involution was observed, compared with WT mice. NOS2-KO mice showed increased phosphorylation of STAT (signal transducer and activator of transcription) 5 during weaning, concomitant with increased beta-casein mRNA levels when compared with weaned WT glands, both hallmarks of th…
Genome wide DNA methylation profiling identifies specific epigenetic features in high-risk cutaneous squamous cell carcinoma
2019
ABSTRACTCutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer. Although most cSCCs have good prognosis, a subgroup of high-risk cSCC has a higher frequency of recurrence and mortality. Therefore, the identification of molecular risk factors associated with this aggressive subtype is of major interest. In this work we carried out a global-scale approach to investigate the DNA-methylation profile in patients at different stages, from premalignant actinic keratosis to low-risk invasive and high-risk non-metastatic and metastatic cSCC. The results showed massive non-sequential changes in DNA-methylome and identified a minimal methylation signature that discriminates bet…
In vivo GSH depletion induces c-myc expression by modulation of chromatin protein complexes.
2009
Abstract We hypothesize that glutathione (GSH) fluctuations could have a prominent role in the modulation of c-myc expression through a mechanism affecting chromatin remodeling complexes. This could lead to an open chromatin structure accessible to transcription factors. We studied the in vivo effect of GSH depletion on these complexes bound to the c-myc promoter in the liver of l-buthionine-(S,R)-sulfoximine (BSO)-treated rats. Using chromatin immunoprecipitation we found that 3 h after BSO treatment the repressing complexes Id2 and Sin3A (part of a histone–deacetylase complex) were released from the c-myc promoter. STAT3 was phosphorylated and associated with its coactivator p300 with int…
Epigenetic modifiers are necessary but not sufficient for reprogramming non-myelinating cells into myelin gene-expressing cells.
2010
Background Modifications on specific histone residues and DNA methylation play an essential role in lineage choice and cellular reprogramming. We have previously shown that histone modifications or combinatorial codes of transcription factors (TFs) are critical for the differentiation of multipotential progenitors into myelinating oligodendrocytes. In this study we asked whether combining global manipulation of DNA methylation and histone acetylation together with the expression of oligodendrocyte- specific TFs, was sufficient to switch the identity of fibroblasts into myelin gene-expressing cells. Methodology/Principal Findings Transfection of six oligodendrocyte-specific TFs (Olig1, Olig2…
Identification of Epigenetic Methylation Signatures With Clinical Value in Crohn's Disease.
2019
INTRODUCTION: DNA methylation is an epigenetic mechanism that regulates gene expression and represents an important link between genotype, environment, and disease. It is a reversible and inheritable mechanism that could offer treatment targets. We aimed to assess the methylation changes on specific genes previously associated with Crohn's disease (CD) and to study their possible associations with the pathology. METHODS: We included 103 participants and grouped them into 2 cohorts (a first [n = 31] and a second validation [n = 72] cohort), with active CD (aCD) and inactive CD (iCD) and healthy participants (CTR). DNA was obtained from the peripheral blood and analyzed by the Agena platform.…
Vitamin E deficiency induces liver nuclear factor-κB DNA-binding activity and changes in related genes
2005
The biological functions of vitamin E have been classically attributed to its property as a potent inhibitor of lipid peroxidation in cellular membranes. However, in 1991, Azzi's group first described that alpha-tocopherol inhibits smooth muscle cell proliferation in a protein kinase C (PKC)-dependent way, demonstrating a non-antioxidant cell signalling function for vitamin E. More recently, the capacity of alpha-tocopherol to modulate gene expression with the implication of different transcription factors, beyond its antioxidant properties, has also been established. This study was to determine the effect of vitamin E-deficiency on liver nuclear factor-kappa B (NF-kappaB) DNA-binding activ…
miRNAs Regulation and Its Role as Biomarkers in Endometriosis.
2016
MicroRNAs (miRNAs) are small non-coding RNAs (18-22 nt) that function as modulators of gene expression. Since their discovery in 1993 in C. elegans, our knowledge about their biogenesis, function, and mechanism of action has increased enormously, especially in recent years, with the development of deep-sequencing technologies. New biogenesis pathways and sources of miRNAs are changing our concept about these molecules. The study of the miRNA contribution to pathological states is a field of great interest in research. Different groups have reported the implication of miRNAs in pathologies such as cancer, diabetes, cardiovascular, and gynecological diseases. It is also well-known that miRNAs…
NF-ĸB as node for signal amplification during weaning.
2011
Post-lactational involution has been reported to share common features with breast tumor development. A deep characterization of the signaling triggered after weaning would help to unveil the complex relationship between involution and breast cancer. NF-κB, a crucial factor in the involuting gland, might be an important regulatory node for signal amplification after weaning; however there is limited information about the identity of NF-κB-target genes and the molecular mechanisms leading to the selection of genes involved in a particular biological process. We identified 4532 target genes in mammary gland at 48h weaning, by genome-wide analysis of regions bound by RelA(p65)-NF-κB in vivo. I…
Oxidative and nitrosative stress in acute pancreatitis. Modulation by pentoxifylline and oxypurinol
2011
Item does not contain fulltext Reactive oxygen species are considered mediators of the inflammatory response and tissue damage in acute pancreatitis. We previously found that the combined treatment with oxypurinol - as inhibitor of xanthine oxidase- and pentoxifylline - as inhibitor of TNF-alpha production-restrained local and systemic inflammatory response and decreased mortality in experimental acute pancreatitis. Our aims were (1) to determine the time-course of glutathione depletion and oxidation in necrotizing pancreatitis in rats and its modulation by oxypurinol and pentoxifylline; (2) to determine whether TNF-alpha is responsible for glutathione depletion in acute pancreatitis; and (…
Role of Redox Signaling, Protein Phosphatases and Histone Acetylation in the Inflammatory Cascade in Acute Pancreatitis: Therapeutic Implications
2010
Acute pancreatitis starts as a local inflammation of the pancreatic tissue but often leads to the systemic inflammatory response syndrome and death by multiple organ failure. Pro-inflammatory cytokines, particularly TNF-alpha and Il-1beta, play a pivotal role together with oxidative stress and glutathione depletion in the inflammatory response in this disease. Most inflammatory mediators act through mitogen activated protein kinases and nuclear factor kB. Nevertheless, elucidation of the precise mechanisms involved in activation and attenuation phases of the inflammatory cascade is still underway. Redox signaling mediated by inactivation of protein phosphatases and histone acetylation trigg…
Molecular mechanisms of Id2 down-regulation in rat liver after acetaminophen overdose. Protection by N-acetyl-L-cysteine.
2010
Id2 is a pleiotropic protein whose function depends on its expression levels. Id2-deficient cells show increased cell death. This study explored the molecular mechanisms for the modulation of Id2 expression elicited by GSH and oxidative stress in the liver of acetaminophen (APAP)-intoxicated rats. APAP-overdose induced GSH depletion, Id2 promoter hypoacetylation, RNApol-II released and, therefore, Id2 down-regulation. Id2 expression depends on c-Myc binding to its promoter. APAP-overdose decreased c-Myc content and binding to Id2 promoter. Reduction of c-Myc was not accompanied by decreased c-myc mRNA, suggesting a mechanism dependent on protein stability. Administration of N-acetyl-cystein…
Glutamate cysteine ligase up-regulation fails in necrotizing pancreatitis
2007
Glutathione depletion is a key factor in the development of acute pancreatitis. Our aim was to study the regulation of glutamate cysteine ligase, the rate-limiting enzyme in glutathione synthesis, in edematous or necrotizing pancreatitis in rats. Glutathione levels were kept low in necrotizing pancreatitis for several hours, with no increase in protein or mRNA levels of glutamate cysteine ligase subunits, despite binding of RNA polymerase II to their promoters and coding regions. The survival signal pathway mediated by ERK and c-MYC was activated, and c-MYC was recruited to the promoters. The failure in gene up-regulation seems to be due to a marked increase in cytosolic ribonuclease activi…
Id2 leaves the chromatin of the E2F4-p130-controlled c-myc promoter during hepatocyte priming for liver regeneration
2006
The Id (inhibitor of DNA binding or inhibitor of differentiation) helix–loop–helix proteins are involved in the regulation of cell growth, differentiation and cancer. The fact that the molecular mechanisms of liver regeneration are not completely understood prompted us to study the fate of Id2 in proliferating liver. Id2 increases in liver regeneration after partial hepatectomy, following the early induction of its gene. Co-immunoprecipitation shows that Id2 forms a complex with E2F4, p130 and mSin3A in quiescent liver and all these components are present at the c-myc promoter as shown using ChIP (chromatin immunoprecipitation). Activation of c-myc during hepatocyte priming (G0–G1 transitio…
Protein phosphatases and chromatin modifying complexes in the inflammatory cascade in acute pancreatitis
2010
Acute pancreatitis is an inflammation of the pancreas that may lead to systemic inflammatory response syndrome and death due to multiple organ failure. Acinar cells, together with leukocytes, trigger the inflammatory cascade in response to local damage of the pancreas. Amplification of the inflammatory cascade requires up-regulation of pro-inflammatory cytokines and this process is mediated not only by nuclear factor κB but also by chromatin modifying complexes and chromatin remodeling. Among the different families of histone acetyltransferases, the p300/CBP family seems to be particularly associated with the inflammatory process. cAMP activates gene expression via the cAMP-responsive eleme…
RNAPol-ChIP: a novel application of chromatin immunoprecipitation to the analysis of real-time gene transcription.
2004
We describe a procedure, RNAPol-ChIP, to measure actual transcriptional rate. It consists of the detection, by chromatin immunoprecipitation (ChIP), of RNA polymerase II within the coding region of genes. To do this, the DNA immunoprecipitated with polymerase antibodies is analysed by PCR, using an amplicon well within the coding region of the desired genes to avoid interferences with polymerase paused at the promoter. To validate RNAPol-ChIP, we compare our results to those obtained by classical methods in several genes induced during either liver regeneration or acute pancreatitis. When short half-life mRNA genes are studied (e.g. c-fos and egr1), RNAPol-ChIP gives results similar to thos…
Epigenetic Regulation of Early- and Late-Response Genes in Acute Pancreatitis
2015
Abstract Chromatin remodeling seems to regulate the patterns of proinflammatory genes. Our aim was to provide new insights into the epigenetic mechanisms that control transcriptional activation of early- and late-response genes in initiation and development of severe acute pancreatitis as a model of acute inflammation. Chromatin changes were studied by chromatin immunoprecipitation analysis, nucleosome positioning, and determination of histone modifications in promoters of proinflammatory genes in vivo in the course of taurocholate-induced necrotizing pancreatitis in rats and in vitro in rat pancreatic AR42J acinar cells stimulated with taurocholate or TNF-α. Here we show that the upregulat…
Cross-talk between oxidative stress and pro-inflammatory cytokines in acute pancreatitis: a key role for protein phosphatases.
2009
Acute pancreatitis is an acute inflammatory process localized in the pancreatic gland that frequently involves peripancreatic tissues. It is still under investigation why an episode of acute pancreatitis remains mild affecting only the pancreas or progresses to a severe form leading to multiple organ failure and death. Proinflammatory cytokines and oxidative stress play a pivotal role in the early pathophysiological events of the disease. Cytokines such as interleukin 1beta and tumor necrosis factor alpha initiate and propagate almost all consequences of the systemic inflammatory response syndrome. On the other hand, depletion of pancreatic glutathione is an early hallmark of acute pancreat…
Pentoxifylline Prevents Loss of PP2A Phosphatase Activity and Recruitment of Histone Acetyltransferases to Proinflammatory Genes in Acute Pancreatitis
2009
Mitogen-activated protein kinases (MAPKs) are considered major signal transducers early during the development of acute pancreatitis. Pentoxifylline is a phosphodiesterase inhibitor with marked anti-inflammatory properties through blockade of extracellular signal regulated kinase (ERK) phosphorylation and tumor necrosis factor alpha production. Our aim was to elucidate the mechanism of action of pentoxifylline as an anti-inflammatory agent in acute pancreatitis. Necrotizing pancreatitis induced by taurocholate in rats and taurocholate-treated AR42J acinar cells were studied. Phosphorylation of ERK and ERK kinase (MEK1/2), as well as PP2A, PP2B, and PP2C serine/threonine phosphatase activiti…
ACTIVIDAD DE LA SER/THR FOSFATASA PP2A Y REGULACIÓN EPIGENÉTICA DE GENES PRO-INFLAMATORIOS EN LA PANCREATITIS AGUDA
2009
Objetivos 1) Estudiar el papel de las serin/treonin protein fosfatasas en la induccion de genes pro-inflamatorios en el pancreas en la pancreatitis aguda, 2) Investigar el papel de las serin/treonin fosfatasas en el mecanismo de accion de la pentoxifilina como agente inflamatorio en la PA. Diseno Modelo de PA necrotica en ratas inducida por taurocolato sodico al 3,5%. Determinacion en pancreas de ratas de la fosforilacion de ERK y MEK1/2 (western blotting), las actividades de las serin/treonin fosfatasas PP2A, PP2B y PP2C, la induccion de genes pro-inflamatorios (RT-PCR e immunoprecipitacion de la cromatina) y el reclutamiento de factores de transcripcion e histonas acetiltransferasas/deace…
Transcription of the MAT2A gene, coding for methionine adenosyltransferase, is up-regulated by E2F and Sp1 at a chromatin level during proliferation …
2006
Methionine adenosyltransferase (MAT) is an essential enzyme because it catalyzes the formation of S-adenosylmethionine, the main methyl donor. Two MAT-encoding genes (MAT1A, MAT2A) are found in mammals. The latter is expressed in proliferating liver, dedifferentiation and cancer, whereas MAT1A is expressed in adult quiescent hepatocytes. Here, we report studies on the molecular mechanisms controlling the induction of MAT2A in regenerating rat liver and in proliferating hepatocytes. The MAT2A is up-regulated at two discrete moments during liver regeneration, as confirmed by RNApol-ChIP analysis. The first one coincides with hepatocyte priming (i.e. G0-G1 transition), while the second one tak…
Additional file 2: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
Thirty-five differentially methylated CpGs between responders and non-responders group selected from 450k array (delta value ≥ 0.2) corresponding to 23 genes located in promoter and island/shore (PPT 172 kb)
Additional file 3: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
Eleven differentially methylated CpGs, corresponding to 11 genes, showed significant methylation differences between non-responder and responder patients: 6 genes (LOC641518; LEF1; HOXA5; EVC2; CDKL2; TLX3) presented a methylation increase in non-responders group vs responders, and 5 genes (ZFHX4; LOC100192378; FERD3L; CHL1; TRIP10) decreased methylation level in non-responder patients compared to those who responded to NAC treatment (PPT 225 kb)
Additional file 1: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
List of all the biological processes enriched for the 71 differentially methylated genes between responder and non-responder patients according to the Gene Ontology analysis (DOCX 32 kb)
Additional file 5: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
Representation of the pathway interaction network of FERD3L and TRIP10 with other genes using Pathway Commons. FERD3L and TRIP10 are able to interact with different genes that have shown to be implicated in cancer drug resistance (PPT 452 kb)
Additional file 4: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
CpGs studied by pyrosequencing in the DC and in the VC to validate methylation in the candidate genes identified in the 450k array (Illumina). In bold, CpGs from 450k array. Normal type, consecutive CpGs (PPT 140 kb)
Additional file 6: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
Mean differences in methylation levels according to clinicopathological prognostic factors in both cohorts (DC+VC). cT, clinical tumor size; cN, clinical nodule affectation (PPTX 48 kb)
Additional file 8: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
Sequence of primers used by pyrosequencing in the validation assay of candidate genes obtained from 450k array (PPT 143 kb)
Additional file 7: of A two-gene epigenetic signature for the prediction of response to neoadjuvant chemotherapy in triple-negative breast cancer pat…
2019
Clinical inclusion and exclusion criteria followed to select TNBC patients for the methylation study (PPT 89 kb)