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1.
Cell Rep Methods ; 2(3): 100187, 2022 03 28.
Artículo en Inglés | MEDLINE | ID: mdl-35475220

RESUMEN

A precise understanding of DNA methylation dynamics is of great importance for a variety of biological processes including cellular reprogramming and differentiation. To date, complex integration of multiple and distinct genome-wide datasets is required to realize this task. We present GwEEP (genome-wide epigenetic efficiency profiling) a versatile approach to infer dynamic efficiencies of DNA modifying enzymes. GwEEP relies on genome-wide hairpin datasets, which are translated by a hidden Markov model into quantitative enzyme efficiencies with reported confidence around the estimates. GwEEP predicts de novo and maintenance methylation efficiencies of Dnmts and furthermore the hydroxylation efficiency of Tets. Its design also allows capturing further oxidation processes given available data. We show that GwEEP predicts accurately the epigenetic changes of ESCs following a Serum-to-2i shift and applied to Tet TKO cells confirms the hypothesized mutual interference between Dnmts and Tets.


Asunto(s)
Proteínas de Unión al ADN , Epigénesis Genética , Proteínas de Unión al ADN/genética , Metilación de ADN/genética , ADN/genética , Diferenciación Celular
2.
Cells ; 11(5)2022 02 23.
Artículo en Inglés | MEDLINE | ID: mdl-35269395

RESUMEN

A significant number of postural orthostatic tachycardia syndrome (POTS) patients have platelet delta granule storage pool deficiency (δ-SPD). The etiology of POTS is unknown but a number of laboratories, including ours, have reported elevations of G-protein-coupled adrenergic receptor and muscarinic acetylcholine receptor autoantibodies in POTS patients, detected by a variety of techniques, suggesting that the disorder is an autoimmune condition. Thus, it could also be considered an inflammatory disease. In a pilot study, we investigated a limited number of platelet-related cytokines and chemokines and discovered many that were elevated. This case−control study validates our pilot study results that POTS patients have an activated innate immune system. Plasma of 35 POTS patients and 35 patients with unexplained bleeding symptoms and categorized as "non-POTS" subjects was analyzed by multiplex flow cytometry to quantify 16 different innate immune system cytokines and chemokines. Electron microscopy was used to quantify platelet dense granules. Ten of 16 biomarkers of inflammation were elevated in plasma from POTS patients compared to non-POTS subjects, with most of the differences extremely significant, with p values < 0.0001. Of particular interest were elevations of IL-1ß and IL-18 and decreased or normal levels of type 1 interferons in POTS patients, suggesting that the etiology of POTS might be autoinflammatory. All POTS patients had δ-SPD. With a growing body of evidence that POTS is an autoimmune disease and having elevations of the innate immune system, our results suggest a potential T-cell-mediated autoimmunity in POTS characteristic of a mixed-pattern inflammatory disease similar to rheumatoid arthritis.


Asunto(s)
Deficiencia de Almacenamiento del Pool Plaquetario , Síndrome de Taquicardia Postural Ortostática , Biomarcadores , Estudios de Casos y Controles , Citocinas , Humanos , Proyectos Piloto , Síndrome de Taquicardia Postural Ortostática/diagnóstico , Receptores Acoplados a Proteínas G
3.
Clin Appl Thromb Hemost ; 27: 10760296211068818, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34939438

RESUMEN

Individuals with bleeding tendencies are more likely to have blood type O than blood types A, B, or AB. Platelet storage pool deficiencies are a lesser-known group of bleeding disorders which often go undiagnosed and may account for a significant number of patients with unexplained bleeding defects. We hypothesized that patients with platelet δ-storage pool deficiency might also have a predominance of type O blood. A retrospective review of medical records of 2,020 patients with unexplained bleeding and evaluated for δ-storage pool deficiency was performed. Correlations between dense granule numbers, blood type, and von Willebrand factor were analyzed for statistical differences. 51.5% of blood samples were blood type O compared to an incidence of 44.0% in the U.S. population. There was a significant association of vWF and blood type O but not with the delta storage pool. There is a preponderance of blood type O in the study population compared to the U.S. population. There is no statistically significant link between blood type O and lower dense granule numbers in this study.


Asunto(s)
Sistema del Grupo Sanguíneo ABO/sangre , Plaquetas/ultraestructura , Agregación Plaquetaria/fisiología , Deficiencia de Almacenamiento del Pool Plaquetario/sangre , Factor de von Willebrand/metabolismo , Adulto , Tiempo de Sangría , Femenino , Humanos , Masculino , Microscopía Electrónica , Deficiencia de Almacenamiento del Pool Plaquetario/patología , Estudios Retrospectivos
4.
J Clin Med ; 10(4)2021 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-33562074

RESUMEN

A growing body of evidence suggests that postural orthostatic tachycardia syndrome (POTS) may be an autoimmune disorder. We have reported in a previous manuscript that 89% of POTS patients (n = 55) had elevations in G-protein-coupled adrenergic A1 receptor autoantibodies and 53% had elevations in muscarinic acetylcholine M4 receptor autoantibodies, as assessed by ELISA. Patients with autoimmune disorders have been reported with a variety of elevated cytokines and cytokines (such as rheumatoid arthritis); thus, we evaluated a limited number of cytokines/chemokines in POTS patients with elevated adrenergic and muscarinic receptor autoantibodies. We utilized the plasma of 34 patients from a previous study; all of the patients (100%) had autoantibodies against the A1 adrenergic receptor and 55.9% (19/34) had autoantibodies against the M4 muscarinic acetylcholine receptor. In particular, the plasma cytokine/chemokine levels were measured as biomarkers of inflammation by Quantibody® technology (Raybiotech, Peachtree Corners, GA, USA). We also evaluated the platelet dense granule numbers, as these patients frequently complain of symptoms related to platelet dysfunction. Patients were predominantly young females who displayed a multitude of co-morbidities but generally reported viral-like symptoms preceding episodes of syncope. Eighty five percent (29/34) had platelet storage pool deficiency. Patients had elevations in five of ten cytokine/chemokines biomarkers (IL1ß, IL21, TNFα, INFγ, and CD30), whereas two biomarkers had decreased levels (CD40L and RANTES). Our observations demonstrate that POTS patients known to have autoantibodies against the G-protein-coupled adrenergic A1 receptor have abnormal plasma concentrations of inflammatory cytokines.

5.
J Am Heart Assoc ; 8(18): e013602, 2019 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-31495251

RESUMEN

Background The etiology of postural orthostatic tachycardia syndrome (POTS) is yet to be established. The disorder is often misdiagnosed as chronic anxiety or a panic disorder because the autonomic failure in these patients is not severe. A growing body of evidence suggests that POTS may be an autoimmune disorder. Antinuclear antibodies and elevations of ganglionic, adrenergic, and muscarinic acetylcholine receptor antibodies have all been reported. Methods and Results We collected detailed clinical symptoms of 55 patients diagnosed with POTS. We also evaluated serum levels of autoantibodies against 4 subtypes of G-protein coupled adrenergic receptors and 5 subtypes of G-protein coupled muscarinic acetylcholine receptors by ELISA. Our patients had a multitude of comorbidities, were predominantly young females, and reported viral-like symptoms preceding episodes of syncope. We detected a significant number of patients with elevated levels of autoantibodies against the adrenergic alpha 1 receptor (89%) and against the muscarinic acetylcholine M4 receptor (53%). Surprisingly, elevations of muscarinic receptor autoantibodies appeared to be dependent upon elevation of autoantibodies against the A1 adrenergic receptor! Four patients had elevations of G-protein coupled autoantibodies against all 9 receptor subtypes measured in our study. Five POTS patients had no elevation of any autoantibody; similarly, controls were also negative for autoantibody elevations. There was a weak correlation of clinical symptom severity with G-protein coupled autoantibodies. Conclusions Our observations provide further evidence that, in most cases, POTS patients have at least 1 elevated G-protein coupled adrenergic autoantibody and, in some instances, both adrenergic and muscarinic autoantibodies, supporting the hypothesis that POTS may be an autoimmune disorder.


Asunto(s)
Autoanticuerpos/inmunología , Síndrome de Taquicardia Postural Ortostática/inmunología , Receptor Muscarínico M4/inmunología , Receptores Adrenérgicos alfa 1/inmunología , Adolescente , Adulto , Estudios de Casos y Controles , Disnea , Fatiga , Femenino , Cefalea , Humanos , Inestabilidad de la Articulación , Masculino , Trastornos Migrañosos , Mialgia , Síndrome de Taquicardia Postural Ortostática/fisiopatología , Receptores Adrenérgicos alfa 2 , Receptores Adrenérgicos beta/inmunología , Receptores Acoplados a Proteínas G/inmunología , Receptores Muscarínicos/inmunología , Adulto Joven
6.
Pediatr Blood Cancer ; 65(4)2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29286575

RESUMEN

MYH9-related disease is a rare cause of thrombocytopenia. We report an infant girl who presented with severe thrombocytopenia at birth and was initially diagnosed with and treated for neonatal alloimmune thrombocytopenia. However, persistent thrombocytopenia led to the suspicion of congenital thrombocytopenia and subsequent identification of a novel variant in MYH9 (E1421K). In silico analysis strongly predicts that this is a disruptive substitution. Immunofluorescent analysis of neutrophils demonstrates abnormal aggregates of MYH9 protein. This case also suggests that a very high immature platelet fraction (≥40%) may be useful for rapidly differentiating MYH9-related disease from other causes of neonatal thrombocytopenia.


Asunto(s)
Proteínas Motoras Moleculares , Mutación Missense , Cadenas Pesadas de Miosina , Agregación Patológica de Proteínas , Trombocitopenia Neonatal Aloinmune , Sustitución de Aminoácidos , Plaquetas/metabolismo , Plaquetas/patología , Femenino , Enfermedades Genéticas Congénitas/sangre , Enfermedades Genéticas Congénitas/genética , Enfermedades Genéticas Congénitas/patología , Enfermedades Genéticas Congénitas/terapia , Humanos , Recién Nacido , Proteínas Motoras Moleculares/genética , Proteínas Motoras Moleculares/metabolismo , Cadenas Pesadas de Miosina/genética , Cadenas Pesadas de Miosina/metabolismo , Neutrófilos/metabolismo , Neutrófilos/patología , Agregación Patológica de Proteínas/genética , Agregación Patológica de Proteínas/metabolismo , Agregación Patológica de Proteínas/patología , Agregación Patológica de Proteínas/terapia , Trombocitopenia Neonatal Aloinmune/sangre , Trombocitopenia Neonatal Aloinmune/genética , Trombocitopenia Neonatal Aloinmune/patología , Trombocitopenia Neonatal Aloinmune/terapia
7.
Phys Occup Ther Pediatr ; 31(1): 31-43, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21058898

RESUMEN

The purpose of this study was to use a systems approach to examine informal communications, meaning those occurring outside of scheduled meetings, among stakeholders in a preschool early intervention program. This investigation expands the discussion of how occupational therapy treatment decisions are made in educational settings by using a systems model to map and understand informal interactions and connections. Eighteen participants shared their experiences, roles, and perspectives regarding the occupational therapy service decision-making process through surveys, interviews, and field notes. Participants were parents, administrators, occupational therapists, teachers, and other related service providers, with three or four members in each participant group. Data was analyzed through the use of descriptive statistics, concept mapping, and coding for themes revealed in detailed interviews and field notes. While the small sample size and single practice setting do not permit generalization of findings, the data suggest that informal communications affecting therapy decisions occurred but were unevenly distributed among stakeholders. Findings suggest the value of utilizing a systems approach to better understand informal interactions that exist apart from scheduled school meetings. Increased awareness of where imbalances exist among team communications can potentially improve practice.


Asunto(s)
Comunicación , Toma de Decisiones , Negociación , Terapia Ocupacional , Personal Administrativo , Preescolar , Niños con Discapacidad , Intervención Educativa Precoz , Educación Especial , Docentes , Personal de Salud , Humanos , Padres , Instituciones Académicas
10.
Occup Ther Health Care ; 21(1-2): 185-98, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-23926978

RESUMEN

This paper focuses on the use of the four specific learner-centered teaching approaches: service-learning, learning through discussion, team-based learning, and a structured research course sequence in an occupational therapy curriculum. These methods are used to develop the four curriculum themes of engagement, critical thinking, innovations in practice, and clinical reasoning. The outcome of these approaches has been that students have taken more responsibility for their learning and shown increased maturity while promoting faculty creativity. Additionally, students have developed skills and interests in social and community engagement, and have sought jobs in community-based practice areas.

11.
Carcinogenesis ; 28(1): 124-9, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16885199

RESUMEN

Budesonide (an anti-inflammatory glucocorticoid), R115777 (a farnesyl transferase inhibitor, Zarnestra, Tipifarnib) or combinations of them were evaluated for prevention of lung tumors and for modulation of DNA methylation in tumors. Lung tumors were induced by vinyl carbamate in female strain A mice. One week later, mice received 60 or 100 mg/kg R115777 by oral gavage and 5 days/week, 0.8 or 1.6 mg/kg of budesonide in their diet, or their combined treatment until killed at 20, 28 and 36 weeks after administering the vinyl carbamate. Other mice were administered the drugs for 2 weeks before killing at Week 20. At Week 20, the rank order for prevention of lung tumors was the combined treatment > budesonide > R115777. At later killings, R115777 was no longer effective, whereas budesonide and the combinations continued to prevent tumors, albeit at a reduced efficacy. DNA hypomethylation in lung tumors was prevented by treatment with R115777, budesonide and the combinations. When administered starting at Week 18 to tumor-bearing mice, the drugs reversed DNA hypomethylation in the tumors. In summary, combined treatment with budesonide and R115777 produced the following results: (i) it was more efficacious in preventing lung tumors than the individual drugs; and (ii) it prevented and reversed DNA hypomethylation in lung tumors. These results support the combined use of budesonide and R115777 in prevention of lung tumors and suggest that reversal of DNA hypomethylation in lung tumors would be useful as a surrogate end-point biomarker for prevention.


Asunto(s)
Antiinflamatorios/uso terapéutico , Budesonida/uso terapéutico , Metilación de ADN/efectos de los fármacos , Neoplasias Pulmonares/prevención & control , Quinolonas/uso terapéutico , Animales , Quimioprevención , Modelos Animales de Enfermedad , Quimioterapia Combinada , Femenino , Neoplasias Pulmonares/inducido químicamente , Ratones , Ratones Endogámicos A , Uretano/análogos & derivados , Uretano/toxicidad
12.
Carcinogenesis ; 27(12): 2442-7, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16733249

RESUMEN

Budesonide (an anti-inflammatory glucocorticoid), R115777 (a farnesyl transferase inhibitor, Zarnestra, Tipifarnib) or combinations of them were evaluated for prevention of lung tumors and for modulation of DNA methylation in tumors. Lung tumors were induced by vinyl carbamate in female Strain A mice. One week later, mice received 60 or 100 mg/kg R115777 by oral gavage and 5 days/week, 0.8 or 1.6 mg/kg of budesonide in their diet, or their combined treatment until killed at 20, 28 and 36 weeks after administering the vinyl carbamate. Other mice were administered the drugs for 2 weeks before killing at 20 weeks. At Week 20, the rank order for prevention of lung tumors was the combined treatment>budesonide>R115777. At later killings, R115777 was no longer effective, whereas budesonide and the combinations continued to prevent tumors, albeit at a reduced efficacy. DNA hypomethylation in lung tumors was prevented by treatment with R115777, budesonide and the combinations. When administered starting at Week 18 to tumor-bearing mice, the drugs reversed DNA hypomethylation in the tumors. In summary, combined treatment with budesonide and R115777 produced the following results: (i) it was more efficacious in preventing lung tumors than the individual drugs; and (ii) it prevented and reversed DNA hypomethylation in lung tumors. These results support the combined use of budesonide and R115777 in prevention of lung tumors and suggest that reversal of DNA hypomethylation in lung tumors would be useful as a surrogate endpoint biomarker for prevention.


Asunto(s)
Antiinflamatorios/uso terapéutico , Budesonida/uso terapéutico , Metilación de ADN/efectos de los fármacos , Neoplasias Pulmonares/prevención & control , Quinolonas/uso terapéutico , Animales , Modelos Animales de Enfermedad , Quimioterapia Combinada , Femenino , Ratones , Ratones Endogámicos A
13.
Int J Cancer ; 118(9): 2359-62, 2006 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-16331605

RESUMEN

Targretin has indicated chemotherapeutic activity against nonsmall-cell lung cancer and chemoprevention in rat mammary gland. Therefore, targretin was evaluated for the prevention of 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanol (NNK) and vinyl carbamate-induced lung tumors in female strain A mice. Three experiments were performed: (i) a dose-response study with vinyl carbamate-induced tumors; (ii) a limited treatment study also with vinyl carbamate and (iii) prevention of NNK-induced tumors. In the dose-response study, 0, 10, 30, 100 and 300 mg/kg targretin were administered after vinyl carbamate. Dose levels of 30 mg/kg and greater significantly decreased tumor multiplicity by >19%. However, the efficacy of 30 and 300 mg/kg was not significantly different demonstrating a shallow dose-response relationship. In the limited treatment study, 200 mg/kg targretin was administered to the mice from 4-13, 4-19, 4-25 and 23-25 weeks after vinyl carbamate. Administering targretin from weeks 4-19 and 4-25 decreased the multiplicity of tumors from 35.3 +/- 1.43 to 29.1 +/- 1.51 and 25.0 +/- 0.93, respectively, and along with administering it from weeks 23-25 decreased tumor size. In the third study, when targretin (100 and 300 mg/kg) was administered for 3 weeks after NNK followed by a 20 weeks holding period, tumor multiplicity was reduced from 10.6 +/- 1.13 to 6.38 +/- 0.75 and 4.60 +/- 0.70, respectively. Hence, targretin demonstrated both preventive and therapeutic activity with respect to mouse lung tumors supporting its further development as a preventive and therapeutic agent for lung cancer.


Asunto(s)
Anticarcinógenos/farmacología , Neoplasias Pulmonares/prevención & control , Tetrahidronaftalenos/farmacología , Animales , Bexaroteno , Quimioprevención , Relación Dosis-Respuesta a Droga , Femenino , Ratones , Neoplasias Experimentales/prevención & control , Nitrosaminas/administración & dosificación , Uretano/administración & dosificación , Uretano/análogos & derivados
14.
Toxicol Sci ; 87(2): 344-52, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16014735

RESUMEN

Bromodichloromethane (BDCM), chloroform, dibromoacetic acid (DBA), dichloroacetic acid (DCA), and trichloroacetic acid (TCA) are chlorine disinfection by-products (DBPs) found in drinking water that have indicated renal carcinogenic and/or tumor promoting activity. We have reported that the DBPs caused DNA hypomethylation in mouse liver, which correlated with their carcinogenic and tumor promoting activity. In this study, we determined their ability to cause renal DNA hypomethylation. B6C3F1 mice were administered DCA or TCA concurrently with/without chloroform in their drinking water for 7 days. In male, but not female mouse kidney, DCA, TCA, and to a lesser extent, chloroform decreased the methylation of DNA and the c-myc gene. Coadministering chloroform increased DCA but not TCA-induced DNA hypomethylation. DBA and BDCM caused renal DNA hypomethylation in both male B6C3F1 mice and Fischer 344 rats. We have reported that, in mouse liver, methionine prevented DCA- and TCA-induced hypomethylation of the c-myc gene. To determine whether it would also prevent hypomethylation in the kidneys, male mice were administered methionine in their diet concurrently with DCA or TCA in their drinking water. Methionine prevented both DCA- and TCA-induced hypomethylation of the c-myc gene. The ability of the DBPs to cause hypomethylation of DNA and of the c-myc gene correlated with their carcinogenic and tumor promoting activity in mouse and rat kidney, which should be taken into consideration as part of their risk assessment. That methionine prevents DCA- and TCA-induced hypomethylation of the c-myc gene would suggest it could prevent their carcinogenic activity in the kidney.


Asunto(s)
Metilación de ADN/efectos de los fármacos , Desinfectantes/toxicidad , Riñón/metabolismo , Abastecimiento de Agua/análisis , Acetatos/química , Animales , Ácido Dicloroacético/química , Femenino , Genes myc/genética , Riñón/efectos de los fármacos , Masculino , Metionina/farmacología , Ratones , Ratas , Medición de Riesgo , Ácido Tricloroacético/química
15.
Toxicol Sci ; 82(1): 62-9, 2004 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-15342954

RESUMEN

Dibromoacetic acid (DBA) is a drinking water disinfection by-product. Its analogs, dichloroacetic acid (DCA) and trichloroacetic acid (TCA), are liver carcinogens in rodents. We evaluated the ability of DBA to cause DNA hypomethylation, glycogen accumulation, and peroxisome proliferation that are activities previously reported for the two other haloacetic acids. Female B6C3F1 mice and male Fischer 344 rats were administered 0, 1,000, and 2,000 mg/l DBA in drinking water. The animals were euthanized after 2, 4, 7, and 28 days of exposure. Dibromoacetic acid caused a dose-dependent and time-dependent decrease of 20%-46% in the 5-methylcytosine content of DNA. Hypomethylation of the c-myc gene was observed in mice after 7 days of DBA exposure. Methylation of 24 CpG sites in the insulin-like growth factor 2 (IGF-II) gene was reduced from 80.2% +/- 9.2% to 18.8% +/- 12.9% by 2,000 mg/l DBA for 28 days. mRNA expression of the c-myc and IGF-II genes in mouse liver was increased by DBA. A dose-dependent increase in the mRNA expression of the c-myc gene was also observed in rats. In both mice and rats, DBA caused dose-dependent accumulation of glycogen and an increase of peroxisomal lauroyl-CoA oxidase activity. Hence, DBA, like DCA and TCA, induced hypomethylation of DNA and of the c-myc and IGF-II genes, increased mRNA expression of both genes, and caused peroxisome proliferation. Again like DCA, DBA also induced glycogen accumulation. These results indicate that DBA shares biochemical and molecular activities in common with DCA and/or TCA, suggesting that it might also be a liver carcinogen.


Asunto(s)
Acetatos/toxicidad , Metilación de ADN/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Glucógeno/metabolismo , Hígado/efectos de los fármacos , Peroxisomas/efectos de los fármacos , Acetatos/administración & dosificación , Administración Oral , Animales , Relación Dosis-Respuesta a Droga , Femenino , Expresión Génica/genética , Genes myc/efectos de los fármacos , Genes myc/genética , Factor II del Crecimiento Similar a la Insulina/genética , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos , Proliferadores de Peroxisomas , Peroxisomas/enzimología , Ratas , Ratas Endogámicas F344 , Abastecimiento de Agua
16.
Cancer Lett ; 212(2): 145-51, 2004 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-15279894

RESUMEN

The ability of non-genotoxic colon carcinogens to induce DNA hypomethylation was evaluated. Administering 0, 0.2 and 0.4 mg/kg of 5-aza-2'-deoxycytidine to female mice for 5 days resulted in a dose-related decrease in 5-methylcytosine in colon DNA. Rutin (3.0 mg/kg) and five bile acids (4.0 mg/kg) were administered in the diet to male F344 rats for 14 days. Rutin and four bile acids that promote colon cancer, deoxycholic acid, chenodeoxycholic acid, cholic acid and lithocholic acid caused DNA hypomethylation, while ursodeoxycholic acid that prevents colon cancer did not. Bromodichloromethane (BDCM) was administered to male F344 rats and B6C3F1 mice by gavage at 0, 50 and 100 mg/kg or in their drinking water at 0, 350 and 700 mg/l for up to 28 days. In rats, BDCM decreased DNA methylation, being more effective when administered by gavage, correlating to its greater carcinogenic potency by this route. In mice, BDCM did not decrease DNA methylation, corresponding to its lack of carcinogenic activity in the colon of this species. In summary, the ability of non-genotoxic colon carcinogens to cause DNA hypomethylation correlated with their carcinogenic activity in the colon.


Asunto(s)
Azacitidina/análogos & derivados , Carcinógenos , Neoplasias del Colon/inducido químicamente , Neoplasias del Colon/genética , Metilación de ADN , ADN/efectos de los fármacos , Animales , Azacitidina/farmacología , Ácido Quenodesoxicólico , Ácido Cólico , Colon/efectos de los fármacos , Decitabina , Ácido Desoxicólico , Relación Dosis-Respuesta a Droga , Femenino , Ácido Litocólico , Masculino , Ratones , Ratas , Ratas Endogámicas F344 , Rutina , Factores de Tiempo
18.
Toxicology ; 196(1-2): 127-36, 2004 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-15036762

RESUMEN

Dichloroacetic acid (DCA) and trichloroacetic acid (TCA) are mouse liver carcinogens. DNA hypomethylation is a common molecular event in cancer that is induced by DCA and TCA. Hypomethylation of DNA and the insulin-like growth factor-II (IGF-II) gene was determined in DCA- and TCA-promoted liver tumors. Mouse liver tumors were initiated by N-methyl-N-nitrosourea and promoted by either DCA or TCA. By dot-blot analysis using an antibody for 5-methylcytosine, the DNA in DCA- and TCA-promoted tumors was demonstrated to be hypomethylated. The methylation status of 28 CpG sites in the differentially methylated region-2 (DMR-2) of mouse IGF-II gene was determined. In liver, 79.3 +/- 1.7% of the sites were methylated, while in DCA- and TCA-treated mice, only 46.4 +/- 2.1% and 58.0 +/- 1.7% of them were methylated and 8.7 +/- 2.6% and 10.7 +/- 7.4% were methylated in tumors. The decreased methylation found in liver from mice exposed to DCA or TCA occurred only in the upstream region of DMR-2, while in tumors it occurred throughout the probed region. mRNA expression of the IGF-II gene was increased in DCA- and TCA-promoted liver tumors but not in non-involved liver from DCA- and TCA-exposed mice. The results support the hypothesis that DNA hypomethylation is involved in the mechanism for the tumorigenicity of DCA and TCA.


Asunto(s)
Carcinógenos/toxicidad , Metilación de ADN/efectos de los fármacos , Ácido Dicloroacético/toxicidad , Factor II del Crecimiento Similar a la Insulina/genética , Neoplasias Hepáticas Experimentales/inducido químicamente , Neoplasias Hepáticas Experimentales/genética , Ácido Tricloroacético/toxicidad , 5-Metilcitosina/química , 5-Metilcitosina/metabolismo , Animales , Islas de CpG/efectos de los fármacos , Islas de CpG/genética , ADN/química , Femenino , Inmunohistoquímica , Metilnitrosourea/toxicidad , Ratones , Ratones Endogámicos , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
19.
Mol Carcinog ; 39(2): 79-84, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14750212

RESUMEN

Surrogate end-point biomarkers are being developed as indicators of the efficacy of chemopreventive agents. These biomarkers are molecular and biological end-points that can be modulated by chemopreventive agents in accordance with their efficacy to prevent cancer. DNA hypomethylation is a common alteration found in colon tumors that has the potential of being modulated by chemopreventive agents and thus being useful as a surrogate end-point biomarker. Agents that were either effective or ineffective in preventing colon cancer were evaluated for the ability to modulate DNA hypomethylation in azoxymethane-induced colon tumors in male F344 rats. DNA methylation was determined by Dot Blot Analysis using a mouse monoclonal anti-5-methylcytosine antibody. Colon tumors had a 70% reduction in DNA methylation relative to normal colonic mucosa. DNA methylation in the tumors was increased by 7 days of treatment with agents that have been shown to prevent colon cancer (calcium chloride, alpha-diflouromethylornithine [DFMO], piroxicam, and sulindac), whereas agents shown not to prevent colon cancer in rats (low dose aspirin, 2-carboxyphenyl retinamide [2-CPR], quercetin, 9-cis retinoic acid, and rutin) did not increase DNA methylation. The results suggest that the ability to reverse the DNA hypomethylation in colon tumors could be useful as a surrogate end-point biomarker for chemoprevention of colon cancer.


Asunto(s)
Biomarcadores de Tumor , Neoplasias del Colon/prevención & control , Metilación de ADN , 5-Metilcitosina/análisis , 5-Metilcitosina/inmunología , Animales , Anticarcinógenos/farmacología , Neoplasias del Colon/genética , Neoplasias del Colon/metabolismo , ADN/efectos de los fármacos , Immunoblotting , Ratas , Ratas Endogámicas F344
20.
Toxicol Sci ; 77(2): 243-8, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-14657517

RESUMEN

Dichloroacetic acid (DCA) is a liver carcinogen that induces DNA hypomethylation in mouse liver. To test the involvement of DNA hypomethylation in the carcinogenic activity of DCA, we determined the effect of methionine on both activities. Female B6C3F1 mice were administered 3.2 g/l DCA in their drinking water and 0, 4.0, and 8.0 g/kg methionine in their diet. Mice were sacrificed after 8 and 44 weeks of exposure. After 8 weeks of exposure, DCA increased the liver/body weight ratio and caused DNA hypomethylation, glycogen accumulation, and peroxisome proliferation. Methionine prevented completely the DNA hypomethylation, reduced by only 25% the glycogen accumulation, and did not alter the increased liver/body weight ratio and the proliferation of peroxisomes induced by DCA. After 44 weeks of exposure, DCA induced foci of altered hepatocytes and hepatocellular adenomas. The multiplicity of foci of altered hepatocytes/mouse was increased from 2.41 +/- 0.38 to 3.40 +/- 0.46 by 4.0 g/kg methionine and decreased to 0.94 +/- 0.24 by 8.0 g/kg methionine, suggesting that methionine slowed the progression of foci to tumors. The low and high concentrations of methionine reduced the multiplicity of liver tumors/mouse from 1.28 +/- 0.31 to 0.167 +/- 0.093 and 0.028 +/- 0.028 (i.e., by 87 and 98%, respectively). Thus, the prevention of liver tumors by methionine was associated with its prevention of DNA hypomethylation, indicating that DNA hypomethylation was critical for the carcinogenic activity of DCA.


Asunto(s)
Adenoma de Células Hepáticas/inducido químicamente , Adenoma de Células Hepáticas/prevención & control , Ácido Dicloroacético/toxicidad , Neoplasias Hepáticas/inducido químicamente , Neoplasias Hepáticas/prevención & control , Metionina/farmacología , Proliferadores de Peroxisomas/toxicidad , Animales , Cloro , Metilación de ADN/efectos de los fármacos , Combinación de Medicamentos , Femenino , Glucógeno/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/patología , Ratones , Ratones Endogámicos , Tamaño de los Órganos , Peroxisomas/efectos de los fármacos , Peroxisomas/metabolismo , Purificación del Agua
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