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1.
High Educ (Dordr) ; 84(3): 487-504, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34840343

RESUMEN

Public health edicts necessitated by COVID-19 prompted a rapid pivot to remote online teaching and learning. Two major consequences followed: households became students' main learning space, and technology became the sole medium of instructional delivery. We use the ideas of "digital disconnect" and "digital divide" to examine, for students and faculty, their prior experience with, and proficiency in using, learning technology. We also explore, for students, how household lockdowns and digital capacity impacted learning. Our findings are drawn from 3806 students and 283 faculty instructors from nine higher education institutions across Asia, Australia, Europe, and North America. For instructors, we find little evidence of a digital divide but some evidence of a digital disconnect. However, neither made a difference to self-reported success in transitioning courses. Faculty instructors were impacted in a myriad of diverse ways. For students, we show that closure and confinement measures which created difficult living situations were associated with lower levels of confidence in learning. The digital divide that did exist among students was less influential than were household lockdown measures in undermining student learning.

2.
Biochem Biophys Res Commun ; 503(3): 1349-1355, 2018 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-30017194

RESUMEN

Sirtuins are a family of evolutionary conserved enzymes that dynamically regulate cellular physiology. Mammals have 7 sirtuins, which are located in different cellular compartments. Sirt5, a sirtuin isoform located in multiple subcellular sites, is involved in regulating a diverse range of cellular and metabolic processes through the removal of a range of acyl-lysine modifications on target proteins. Loss of Sirt5 leads to hyper-malonylation and hyper-succinylation of both mitochondrial and extra-mitochondrial proteins, influencing oxidative phosphorylation, the TCA cycle and glycolysis. However despite these findings, the effect of Sirt5 overexpression on metabolism remains poorly investigated. Here we report that overexpression of Sirt5 has minimal effect on mitochondrial metabolism and overall physiology in mice, despite inducing widespread decreases in protein acylation. Our data confirms the role of Sirt5 as an important demalonylase and desuccinylase enzyme in vivo, but questions the relevance of physiological changes in protein acylation levels in the regulation of cellular metabolism.


Asunto(s)
Proteínas Mitocondriales/metabolismo , Sirtuinas/genética , Sirtuinas/metabolismo , Acilación , Animales , Células Cultivadas , Glucosa/administración & dosificación , Inyecciones Intraperitoneales , Ratones , Ratones Transgénicos , Mitocondrias/metabolismo , Fenotipo
3.
Muscle Nerve ; 57(4): 650-658, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-28881481

RESUMEN

INTRODUCTION: Muscle wasting is a frequent, debilitating complication of cancer. The impact of colorectal cancer chemotherapeutic oxaliplatin on the development of muscle loss and associated molecular changes is of clinical importance. METHODS: C57BL/6J male mice were treated with oxaliplatin. Total body weights were measured and behavioral studies performed. Hindlimb muscle weights (gastrocnemius and soleus) were recorded in conjunction with gene and protein expression analysis. RESULTS: Oxaliplatin-treated mice displayed reduced weight gain and behavioral deficits. Mice treated over a shorter course had significantly increased STAT3 phosphorylation in gastrocnemius muscles. Mice receiving extended oxaliplatin treatment demonstrated reduced hindlimb muscle mass with upregulation of myopathy-associated genes Foxo3, MAFbx, and Bnip3. DISCUSSION: The findings suggest that oxaliplatin treatment can directly disrupt skeletal muscle homeostasis and promote muscle loss, which may be clinically relevant in the context of targeting fatigue and weakness in cancer patients. Muscle Nerve 57: 650-658, 2018.


Asunto(s)
Antineoplásicos/farmacología , Expresión Génica/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Oxaliplatino/farmacología , Animales , Peso Corporal/efectos de los fármacos , Proteína Forkhead Box O3/efectos de los fármacos , Proteína Forkhead Box O3/genética , Miembro Posterior , Masculino , Proteínas de la Membrana/efectos de los fármacos , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Proteínas Mitocondriales/efectos de los fármacos , Proteínas Mitocondriales/genética , Proteínas Musculares/efectos de los fármacos , Proteínas Musculares/genética , Músculo Esquelético/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Proteínas Ligasas SKP Cullina F-box/efectos de los fármacos , Proteínas Ligasas SKP Cullina F-box/genética , Factor de Transcripción STAT3/efectos de los fármacos , Factor de Transcripción STAT3/metabolismo
4.
Physiol Genomics ; 47(12): 588-99, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26395599

RESUMEN

Cancer cachexia is a systemic, paraneoplastic syndrome seen in patients with advanced cancer. There is growing interest in the altered muscle pathophysiology experienced by cachectic patients. This study reports the microarray analysis of gene expression in cardiac and skeletal muscle in the colon 26 (C26) carcinoma mouse model of cancer cachexia. A total of 268 genes were found to be differentially expressed in cardiac muscle tissue, compared with nontumor-bearing controls. This was fewer than the 1,533 genes that changed in cachectic skeletal muscle. In addition to different numbers of genes changing, different cellular functions were seen to change in each tissue. The cachectic heart showed signs of inflammation, similar to cachectic skeletal muscle, but did not show the upregulation of ubiquitin-dependent protein catabolic processes or downregulation of genes involved in cellular energetics and muscle regeneration that characterizes skeletal muscle cachexia. Quantitative PCR was used to investigate a subset of inflammatory genes in the cardiac and skeletal muscle of independent cachectic samples; this revealed that B4galt1, C1s, Serpina3n, and Vsig4 were significantly upregulated in cardiac tissue, whereas C1s and Serpina3n were significantly upregulated in skeletal tissue. Our skeletal muscle microarray results were also compared with those from three published microarray studies and found to be consistent in terms of the genes differentially expressed and the functional processes affected. Our study highlights that skeletal and cardiac muscles are affected differently in the C26 mouse model of cachexia and that therapeutic strategies cannot assume that both muscle types will show a similar response.


Asunto(s)
Caquexia/complicaciones , Neoplasias del Colon/complicaciones , Neoplasias del Colon/metabolismo , Músculo Esquelético/metabolismo , Miocardio/metabolismo , Proteínas de Fase Aguda/genética , Proteínas de Fase Aguda/metabolismo , Animales , Modelos Animales de Enfermedad , Músculo Esquelético/fisiopatología , Miocardio/patología , Reacción en Cadena de la Polimerasa , Receptores de Complemento/genética , Receptores de Complemento/metabolismo
5.
Diabetologia ; 57(7): 1410-9, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24733160

RESUMEN

AIMS/HYPOTHESIS: Regulation of insulin secretion along the secretory pathway is incompletely understood. We addressed the expression of SIL1, a nucleotide exchange factor for the endoplasmic reticulum (ER) chaperone glucose-regulated protein 78 kD (GRP78), in pancreatic beta cells and investigated whether or not SIL1 is involved in beta cell function. METHODS: SIL1 expression was analysed by immunoblotting and immunofluorescence. Metabolic and islet variables, including glucose tolerance, beta cell mass, insulin secretion, islet ultrastructure, insulin content and levels of ER stress marker proteins, were addressed in Sil1 knockout (Sil1 (-/-)) mice. Insulin, proinsulin and C-peptide release was addressed in Sil1 (-/-) islets, and SIL1 overexpression or knockdown was explored in MIN6 cells in vitro. Models of type 1 diabetes and insulin resistance were induced in Sil1 (-/-) mice by administration of streptozotocin (STZ) and a high-fat diet (HFD), respectively. RESULTS: We show that SIL1 is expressed in pancreatic beta cells and is required for islet insulin content, islet sizing, glucose tolerance and glucose-stimulated insulin secretion in vivo. Levels of pancreatic ER stress markers are increased in Sil1 (-/-) mice, and Sil1 (-/-) beta cell ER is ultrastructurally compromised. Isolated Sil1 (-/-) islets show lower proinsulin and insulin content and impaired glucose-stimulated insulin secretion. Modulation of SIL1 protein levels in MIN6 cells correlates with changes in insulin content and secreted insulin. Furthermore, Sil1 (-/-) mice are more susceptible to STZ-induced type 1 diabetes with increased apoptosis. Upon HFD feeding, Sil1 (-/-) mice show markedly lower insulin secretion and exacerbated glucose intolerance compared with control mice. Surprisingly, however, HFD-fed Sil1 (-/-) mice display pronounced islet hyperplasia with low amounts of insulin in total pancreas. CONCLUSIONS/INTERPRETATION: These results reveal a novel role for the nucleotide exchange factor SIL1 in pancreatic beta cell function under physiological and disease conditions such as diabetes and the metabolic syndrome.


Asunto(s)
Retículo Endoplásmico/metabolismo , Glucosa/farmacología , Factores de Intercambio de Guanina Nucleótido/metabolismo , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Animales , Chaperón BiP del Retículo Endoplásmico , Estrés del Retículo Endoplásmico/fisiología , Factores de Intercambio de Guanina Nucleótido/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/efectos de los fármacos , Ratones , Ratones Noqueados
6.
BMC Med Educ ; 14: 222, 2014 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-25331335

RESUMEN

BACKGROUND: Providing large numbers of undergraduate students in scientific disciplines with engaging, authentic laboratory experiences is important, but challenging. Virtual laboratories (vLABs) are a potential means to enable interactive learning experiences. A vLAB focusing on Western Blotting was developed and implemented in a 3rd year undergraduate Pathology course for science students to facilitate learning of technical molecular laboratory skills that are linked to development of diagnostic skills. Such skills are important for undergraduates in building a conceptual understanding of translation of laboratory techniques to changes in human biology due to disease. METHODS: The Western Blotting vLAB was developed and deployed using the Adaptive eLearning Platform (AeLP) developed by Smart Sparrow (https://www.smartsparrow.com/). The vLAB was evaluated to assess students' perceptions of their laboratory skills relevant to the diagnosis of Muscular Dystrophy. A blended learning rotation model was applied in which wet laboratory and vLAB environments for Western Blotting were both delivered to three consecutive cohorts of 3rd year science undergraduates undertaking a Muscle Diseases practical class. Evaluation questionnaires were administered at the completion of the practical classes. RESULTS: Students indicated in online questionnaires that the Western Blotting vLAB was at least equivalent to the real lab in their perceived development of concepts, laboratory skills and diagnosis of disease. CONCLUSIONS: vLABs have great potential for improving students' development of diagnostic skills. Further studies are required to determine the impact of vLABs on student learning.


Asunto(s)
Western Blotting , Educación de Pregrado en Medicina , Patología Molecular/educación , Interfaz Usuario-Computador , Adulto , Actitud del Personal de Salud , Competencia Clínica , Estudios de Cohortes , Instrucción por Computador , Retroalimentación , Femenino , Humanos , Masculino , Distrofias Musculares/genética , Distrofias Musculares/patología , Diseño de Software , Encuestas y Cuestionarios , Adulto Joven
7.
J Cachexia Sarcopenia Muscle ; 15(1): 112-123, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38124345

RESUMEN

BACKGROUND: Decreased insulin availability and high blood glucose levels, the hallmark features of poorly controlled diabetes, drive disease progression and are associated with decreased skeletal muscle mass. We have shown that mice with ß-cell dysfunction and normal insulin sensitivity have decreased skeletal muscle mass. This project asks how insulin deficiency impacts on the structure and function of the remaining skeletal muscle in these animals. METHODS: Skeletal muscle function was determined by measuring exercise capacity and specific muscle strength prior to and after insulin supplementation for 28 days in 12-week-old mice with conditional ß-cell deletion of the ATP binding cassette transporters ABCA1 and ABCG1 (ß-DKO mice). Abca1 and Abcg1 floxed (fl/fl) mice were used as controls. RNAseq was used to quantify changes in transcripts in soleus and extensor digitorum longus muscles. Skeletal muscle and mitochondrial morphology were assessed by transmission electron microscopy. Myofibrillar Ca2+ sensitivity and maximum isometric single muscle fibre force were assessed using MyoRobot biomechatronics technology. RESULTS: RNA transcripts were significantly altered in ß-DKO mice compared with fl/fl controls (32 in extensor digitorum longus and 412 in soleus). Exercise capacity and muscle strength were significantly decreased in ß-DKO mice compared with fl/fl controls (P = 0.012), and a loss of structural integrity was also observed in skeletal muscle from the ß-DKO mice. Supplementation of ß-DKO mice with insulin restored muscle integrity, strength and expression of 13 and 16 of the dysregulated transcripts in and extensor digitorum longus and soleus muscles, respectively. CONCLUSIONS: Insulin insufficiency due to ß-cell dysfunction perturbs the structure and function of skeletal muscle. These adverse effects are rectified by insulin supplementation.


Asunto(s)
Insulina , Músculo Esquelético , Ratones , Animales , Insulina/farmacología , Insulina/metabolismo , Músculo Esquelético/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Mitocondrias/metabolismo
8.
Methods Mol Biol ; 2644: 193-209, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37142923

RESUMEN

Cellular health, functionality, response to environment, and other variables affecting cell, tissue, or organ viability are reflected in the cellular proteomes and metabolomes. These "omic" profiles are in constant flux even during normal cellular functioning, to maintain cellular homeostasis, in response to small environmental changes and maintenance of optimal cell viability. However proteomic "fingerprints" can also provide insight into cellular ageing, response to disease, adjustment to environmental changes, and other variables that impact cellular viability. A variety of proteomic methods can be used to determine qualitative and quantitative proteomic change. In this chapter, we will focus on a labeling method called isobaric tags for relative and absolute quantification (iTRAQ), which is frequently used to identify and quantify proteomic expression changes in cells and tissues.


Asunto(s)
Proteoma , Proteómica , Proteómica/métodos , Supervivencia Celular , Marcaje Isotópico/métodos
9.
Clin Cancer Res ; 27(5): 1438-1451, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33310889

RESUMEN

PURPOSE: TERT gene rearrangement with transcriptional superenhancers leads to TERT overexpression and neuroblastoma. No targeted therapy is available for clinical trials in patients with TERT-rearranged neuroblastoma. EXPERIMENTAL DESIGN: Anticancer agents exerting the best synergistic anticancer effects with BET bromodomain inhibitors were identified by screening an FDA-approved oncology drug library. The synergistic effects of the BET bromodomain inhibitor OTX015 and the proteasome inhibitor carfilzomib were examined by immunoblot and flow cytometry analysis. The anticancer efficacy of OTX015 and carfilzomib combination therapy was investigated in mice xenografted with TERT-rearranged neuroblastoma cell lines or patient-derived xenograft (PDX) tumor cells, and the role of TERT reduction in the anticancer efficacy was examined through rescue experiments in mice. RESULTS: The BET bromodomain protein BRD4 promoted TERT-rearranged neuroblastoma cell proliferation through upregulating TERT expression. Screening of an approved oncology drug library identified the proteasome inhibitor carfilzomib as the agent exerting the best synergistic anticancer effects with BET bromodomain inhibitors including OTX015. OTX015 and carfilzomib synergistically reduced TERT protein expression, induced endoplasmic reticulum stress, and induced TERT-rearranged neuroblastoma cell apoptosis which was blocked by TERT overexpression and endoplasmic reticulum stress antagonists. In mice xenografted with TERT-rearranged neuroblastoma cell lines or PDX tumor cells, OTX015 and carfilzomib synergistically blocked TERT expression, induced tumor cell apoptosis, suppressed tumor progression, and improved mouse survival, which was largely reversed by forced TERT overexpression. CONCLUSIONS: OTX015 and carfilzomib combination therapy is likely to be translated into the first clinical trial of a targeted therapy in patients with TERT-rearranged neuroblastoma.


Asunto(s)
Acetanilidas/farmacología , Proteínas de Ciclo Celular/antagonistas & inhibidores , Reordenamiento Génico , Compuestos Heterocíclicos con 3 Anillos/farmacología , Terapia Molecular Dirigida/métodos , Neuroblastoma/tratamiento farmacológico , Oligopéptidos/farmacología , Telomerasa/genética , Factores de Transcripción/antagonistas & inhibidores , Animales , Apoptosis , Proliferación Celular , Quimioterapia Combinada , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Neuroblastoma/metabolismo , Neuroblastoma/patología , Inhibidores de Proteasoma/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto
10.
Med Sci Educ ; 29(2): 357-361, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34457492

RESUMEN

INTRODUCTION: Narratives (as opposed to stories) can assess multiple facets of the same problem through the viewpoints of different characters. METHODS: Narratives related to three cancer patients, from diagnosis to cure or death, were used to teach seven cancer-related themes in a Cancer Pathology course offered to third-year medical science and science (college) undergraduates. RESULTS: The majority of students preferred narrative-based learning compared with traditional learning methods because they felt that it improved their learning experience and retention of information. CONCLUSION: Narrative-based learning may improve the learning experience of students by contextualizing complex concepts and highlighting real-world applications of knowledge.

11.
Neurogenetics ; 9(3): 191-5, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18458969

RESUMEN

X-linked Charcot-Marie-Tooth (CMTX) disease is a common inherited degenerative disorder of the peripheral nerve. Previously, our laboratory identified a large New Zealand/United Kingdom (NZ/UK) family mapping to the CMTX3 locus (Xq26.3-27.1). We have now identified a second large, Australian X-linked CMT family that links to the CMTX3 locus. This new family has the same phenotype as our previously described CMTX3 family, with slightly milder disease in males than CMTX1 and asymptomatic carrier females. This study also includes the re-analysis of one of the original US pedigrees reporting the CMTX3 locus. The large Australian family shared the complete disease haplotype with our original NZ/UK family, while the American family shared only the distal portion of the disease haplotype. Comparison of the frequency of the CMTX3 haplotype to the normal population showed strong statistical evidence (p < 0.0001) indicating that the smaller shared haplotype is identical by descent. This suggests that the new CMTX3 family, our previously reported family, and the original American CMTX3 family have a common ancestor, and the disease in these families is caused by a founder mutation. The ancestral recombination observed in the American family refines the CMTX3 interval to a 2.5 Mb region between DXS984 and DXS8106. In this region, 11 out of the 15 annotated genes have been excluded for pathogenic mutations.


Asunto(s)
Enfermedad de Charcot-Marie-Tooth/genética , Efecto Fundador , Enfermedades Genéticas Ligadas al Cromosoma X/genética , Mutación , Australia , Femenino , Genes Ligados a X , Ligamiento Genético , Haplotipos , Humanos , Escala de Lod , Masculino , Linaje , Fenotipo , Polimorfismo de Nucleótido Simple
12.
Oncotarget ; 9(31): 22001-22022, 2018 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-29774118

RESUMEN

BACKGROUND: Cancer cachexia is observed in more than 50% of advanced cancer patients, and impairs quality of life and prognosis. A variety of pathways are likely to be dysregulated. Hence, a broad-spectrum understanding of the disease process is best achieved by a discovery based approach such as proteomics. RESULTS: More than 300 proteins were identified with > 95% confidence in correct sequence identification, of which 5-10% were significantly differentially expressed in cachectic tissues (p-value of 0.05; 27 proteins from gastrocnemius, 34 proteins from soleus and 24 proteins from heart). The two most pronounced functional groups being sarcomeric proteins (mostly upregulated across all three muscle types) and energy/metabolism proteins (mostly downregulated across all muscle types). Electron microscopy revealed disintegration of the sarcomere and morphological aberrations of mitochondria in the cardiac muscle of colon 26 (C26) carcinoma mice. MATERIALS AND METHODS: The colon 26 (C26) carcinoma mouse model of cachexia was used to analyse soleus, gastrocnemius and cardiac muscles using two 8-plex iTRAQ proteomic experiments and tandem mass spectrometry (LCMSMS). Differentially expressed proteomic lists for protein clustering and enrichment of biological processes, molecular pathways, and disease related pathways were analysed using bioinformatics. Cardiac muscle ultrastructure was explored by electron microscopy. CONCLUSIONS: Morphological and proteomic analyses suggested molecular events associated with disintegrated sarcomeric structure with increased dissolution of Z-disc and M-line proteins. Altered mitochondrial morphology, in combination with the reduced expression of proteins regulating substrate and energy metabolism, suggest that muscle cells are likely to be undergoing a state of energy crisis which ultimately results in cancer-induced cachexia.

13.
Int J Biochem Cell Biol ; 39(3): 478-83, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17188925

RESUMEN

The Pregnane X Receptor (PXR) is pivotal for the body's response to toxic xenobiotics and endogenous metabolites. By acting as a ligand-activated transcription factor, PXR regulates all stages of xenobiotic metabolism and transport and is responsible for important inductive drug interactions. Screening assays to assess the PXR activation potential of new and existing drugs are becoming integral components of drug discovery programs. PXR is also involved in lipid homeostasis providing opportunities for treatments based on PXR agonists for diseases involving aberrant cholesterol and bile acid levels. The expression of PXR in many other tissues besides liver and intestine suggest PXR may have additional protective functions in the body, which contribute to disease outcomes in diverse clinical situations with potential for novel therapeutic approaches.


Asunto(s)
Receptores de Esteroides/metabolismo , Secuencia de Aminoácidos , Animales , Humanos , Inactivación Metabólica , Metabolismo de los Lípidos , Ratones , Modelos Biológicos , Datos de Secuencia Molecular , Receptor X de Pregnano , Receptores de Esteroides/química , Receptores de Esteroides/genética , Homología de Secuencia de Aminoácido , Xenobióticos/metabolismo
14.
Cancer Res ; 77(9): 2522-2533, 2017 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-28209620

RESUMEN

Myc oncoproteins exert tumorigenic effects by regulating expression of target oncogenes. Histone H3 lysine 79 (H3K79) methylation at Myc-responsive elements of target gene promoters is a strict prerequisite for Myc-induced transcriptional activation, and DOT1L is the only known histone methyltransferase that catalyzes H3K79 methylation. Here, we show that N-Myc upregulates DOT1L mRNA and protein expression by binding to the DOT1L gene promoter. shRNA-mediated depletion of DOT1L reduced mRNA and protein expression of N-Myc target genes ODC1 and E2F2 DOT1L bound to the Myc Box II domain of N-Myc protein, and knockdown of DOT1L reduced histone H3K79 methylation and N-Myc protein binding at the ODC1 and E2F2 gene promoters and reduced neuroblastoma cell proliferation. Treatment with the small-molecule DOT1L inhibitor SGC0946 reduced H3K79 methylation and proliferation of MYCN gene-amplified neuroblastoma cells. In mice xenografts of neuroblastoma cells stably expressing doxycycline-inducible DOT1L shRNA, ablating DOT1L expression with doxycycline significantly reduced ODC1 and E2F2 expression, reduced tumor progression, and improved overall survival. In addition, high levels of DOT1L gene expression in human neuroblastoma tissues correlated with high levels of MYCN, ODC1, and E2F2 gene expression and independently correlated with poor patient survival. Taken together, our results identify DOT1L as a novel cofactor in N-Myc-mediated transcriptional activation of target genes and neuroblastoma oncogenesis. Furthermore, they characterize DOT1L inhibitors as novel anticancer agents against MYCN-amplified neuroblastoma. Cancer Res; 77(9); 2522-33. ©2017 AACR.


Asunto(s)
Metiltransferasas/genética , Proteína Proto-Oncogénica N-Myc/genética , Neuroblastoma/genética , Transcripción Genética , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Metilación de ADN/efectos de los fármacos , Inhibidores Enzimáticos/administración & dosificación , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Histona Metiltransferasas , N-Metiltransferasa de Histona-Lisina/antagonistas & inhibidores , N-Metiltransferasa de Histona-Lisina/genética , Humanos , Metiltransferasas/antagonistas & inhibidores , Ratones , Proteína Proto-Oncogénica N-Myc/biosíntesis , Neuroblastoma/tratamiento farmacológico , Neuroblastoma/patología , Regiones Promotoras Genéticas
15.
Curr Drug Targets ; 17(10): 1140-6, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-25882219

RESUMEN

Cancer cachexia is a debilitating paraneoplastic wasting syndrome characterized by skeletal muscle depletion and unintentional weight loss. It affects up to 50-80% of patients with cancer and directly accounts for one-quarter of cancer-related deaths due to cardio-respiratory failure. Muscle weakness, one of the hallmarks of this syndrome, has been postulated to be due to a combination of muscle breakdown, dysfunction and decrease in the ability to repair, with effective treatment strategies presently limited. Excessive inflammatory cytokine levels due to the host-tumor interaction, such as Interleukin (IL)-6 and Tumor Necrosis Factor (TNF)-α, are hypothesised to drive this pathological process but the specific mechanisms by which these cytokines produce skeletal muscle dysfunction in cancer cachexia remain undefined. Endoplasmic Reticulum (ER) stress and the associated disruptions in calcium signaling have been implicated in cytokine-mediated disruptions in skeletal muscle and function. Disrupted ER stress-related processes such as the Unfolded Protein Response (UPR), calcium homeostasis and altered muscle protein synthesis have been reported in clinical and experimental cachexia and other inflammation-driven muscle diseases such as myositis, potentially suggesting a link between increased IL-6 and TNF-α and ER stress in skeletal muscle cells. As the concept of upregulated ER stress in skeletal muscle cells due to elevated cytokines is novel and potentially very relevant to our understanding of cancer cachexia, this review aims to examine the potential relationship between inflammatory cytokine mediated muscle breakdown and ER stress, in the context of cancer cachexia, and to discuss the molecular signaling pathways underpinning this pathology.


Asunto(s)
Caquexia/etiología , Músculo Esquelético/patología , Neoplasias/complicaciones , Animales , Caquexia/patología , Calcio/metabolismo , Citocinas/metabolismo , Estrés del Retículo Endoplásmico/fisiología , Humanos , Inflamación/patología , Debilidad Muscular/etiología , Debilidad Muscular/patología , Biosíntesis de Proteínas/fisiología , Transducción de Señal/fisiología
17.
Biochem J ; 374(Pt 2): 359-67, 2003 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-12780350

RESUMEN

A human MusTRD (muscle TFII-I repeat domain (RD)-containing protein) isoform was originally identified in a yeast one-hybrid screen as a protein that binds the slow fibre-specific enhancer of the muscle gene troponin I slow [O'Mahoney, Guven, Lin, Joya, Robinson, Wade and Hardeman (1998) Mol. Cell. Biol. 18, 6641-6652]. MusTRD shares homology with the general transcription factor TFII-I by the presence of diagnostic I-RDs [Roy (2001) Gene 274, 1-13]. The human gene encoding MusTRD, GTF2IRD1 ( WBSCR11 / GTF3 ), was subsequently located on chromosome 7q11.23, a region deleted in the neurodegenerative disease, Williams-Beuren Syndrome [Osborne, Campbell, Daradich, Scherer, Tsui, Franke, Peoples, Francke, Voit, Kramer et al. (1999) Genomics 57, 279-284; Franke, Peoples and Francke (1999) Cytogenet. Cell. Genet. 86, 296-304; Tassabehji, Carette, Wilmot, Donnai, Read and Metcalfe (1999) Eur. J. Hum. Genet. 7, 737-747]. The haploinsufficiency of MusTRD has been implicated in the myopathic aspect of this disease, which manifests itself in symptoms such as lowered resistance to fatigue, kyphoscoliosis, an abnormal gait and joint contractures [Tassabehji, Carette, Wilmot, Donnai, Read and Metcalfe (1999) Eur. J. Hum. Genet. 7, 737-747]. Here, we report the identification of 11 isoforms of MusTRD in mouse skeletal muscles. These isoforms were isolated from a mouse skeletal muscle cDNA library and reverse transcription-PCR on RNA from various adult and embryonic muscles. The variability in these isoforms arises from alternative splicing of a combination of four cassettes and two mutually exclusive exons, all in the 3' region of the primary transcript of Gtf2ird1, the homologous mouse gene. The expression of some of these isoforms is differentially regulated spatially, suggesting individual regulation of the expression of these isoforms. Co-transfection studies in C2C12 muscle cell cultures reveal that isoforms differentially regulate muscle fibre-type-specific promoters. This indicates that the presence of different domains of MusTRD influences the activity exerted by this molecule on multiple promoters active in skeletal muscle.


Asunto(s)
Empalme Alternativo , Regulación de la Expresión Génica , Fibras Musculares de Contracción Lenta/fisiología , Proteínas Musculares/genética , Proteínas Nucleares , Regiones Promotoras Genéticas , Transactivadores , Factores de Transcripción/genética , Secuencias de Aminoácidos , Animales , Línea Celular , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/fisiología , Elementos de Facilitación Genéticos/genética , Perfilación de la Expresión Génica , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Fibras Musculares de Contracción Lenta/citología , Fibras Musculares de Contracción Lenta/metabolismo , Proteínas Musculares/metabolismo , Proteínas Musculares/fisiología , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/fisiología , Factores de Transcripción/metabolismo , Factores de Transcripción/fisiología
18.
Am J Cancer Res ; 5(9): 2823-37, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26609488

RESUMEN

DOT1L is a unique histone methyltransferase that targets the histone H3 lysine 79 (H3K79) residue for mono-, di- and tri- methylation. Histone H3K79 mono- and di-methylation results in active gene transcription, while H3K79 tri-methylation is associated with gene repression. DOT1L has a critical role in regulating gene transcription, development, cell cycle progression, somatic reprogramming and DNA damage repair. DOT1L interacts with Mixed Lineage Leukemia (MLL) fusion proteins, leading to enhanced H3K79 methylation, maintenance of open chromatin, overexpression of downstream oncogenes and leukemogenesis. Importantly, small molecule DOT1L inhibitors have been recently developed, and one of the DOT1L inhibitors is already under investigation in a Phase I clinical trial in patients with MLL fusion gene-driven leukemia.

19.
Front Physiol ; 5: 145, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24782788

RESUMEN

Myopathy is a feature of many inflammatory syndromes. Chronic inflammation has been linked to pathophysiological mechanisms which implicate 1,25 dihydroxyvitamin D3 (1,25-(OH)2D3)-mediated signaling pathways with emerging evidence supporting a role for the vitamin D receptor (VDR) in contractile and metabolic function of both skeletal and cardiac muscle. Altered VDR expression in skeletal and cardiac muscle has been reported to result in significant effects on metabolism, calcium signaling and fibrosis in these tissues. Elevated levels of serum inflammatory cytokines, such as IL-6, TNF-α and IFNγ, have been shown to impact myogenic and nuclear receptor signaling pathways in cancer-induced cachexia. The dysregulation of nuclear receptors, such as VDR and RXRα in muscle cells, has also been postulated to result in myopathy via their effects on muscle structural integrity and metabolism. Future research directions include generating transcriptome-wide information incorporating VDR and its gene targets and using systems biology approaches to identify altered molecular networks in human tissues such as muscle. These approaches will aid in the development of novel therapeutic targeting strategies for inflammation-induced myopathies.

20.
J Natl Cancer Inst ; 106(7)2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24906397

RESUMEN

BACKGROUND: Patients with neuroblastoma due to the amplification of a 130-kb genomic DNA region containing the MYCN oncogene have poor prognoses. METHODS: Bioinformatics data were used to discover a novel long noncoding RNA, lncUSMycN, at the 130-kb amplicon. RNA-protein pull-down assays were used to identify proteins bound to lncUSMycN RNA. Kaplan-Meier survival analysis, multivariable Cox regression, and two-sided log-rank test were used to examine the prognostic value of lncUSMycN and NonO expression in three cohorts of neuroblastoma patients (n = 47, 88, and 476, respectively). Neuroblastoma-bearing mice were treated with antisense oligonucleotides targeting lncUSMycN (n = 12) or mismatch sequence (n = 13), and results were analyzed by multiple comparison two-way analysis of variance. All statistical tests were two-sided. RESULTS: Bioinformatics data predicted lncUSMycN gene and RNA, and reverse-transcription polymerase chain reaction confirmed its three exons and two introns. The lncUSMycN gene was coamplified with MYCN in 88 of 341 human neuroblastoma tissues. lncUSMycN RNA bound to the RNA-binding protein NonO, leading to N-Myc RNA upregulation and neuroblastoma cell proliferation. High levels of lncUSMycN and NonO expression in human neuroblastoma tissues independently predicted poor patient prognoses (lncUSMycN: hazard ratio [HR] = 1.87, 95% confidence interval [CI] = 1.06 to 3.28, P = .03; NonO: HR = 2.48, 95% CI = 1.34 to 4.57, P = .004). Treatment with antisense oligonucleotides targeting lncUSMycN in neuroblastoma-bearing mice statistically significantly hindered tumor progression (P < .001). CONCLUSIONS: Our data demonstrate the important roles of lncUSMycN and NonO in regulating N-Myc expression and neuroblastoma oncogenesis and provide the first evidence that amplification of long noncoding RNA genes can contribute to tumorigenesis.


Asunto(s)
Genes myc , Neuroblastoma/metabolismo , Neuroblastoma/patología , Proteínas Nucleares/genética , Proteínas Oncogénicas/genética , Proteínas Proto-Oncogénicas/genética , ARN Largo no Codificante/metabolismo , Animales , Proliferación Celular , Proteínas de Unión al ADN/metabolismo , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , Estimación de Kaplan-Meier , Ratones , Proteína Proto-Oncogénica N-Myc , Neuroblastoma/genética , Proteínas Asociadas a Matriz Nuclear/metabolismo , Factores de Transcripción de Octámeros/metabolismo , Oligonucleótidos Antisentido , Valor Predictivo de las Pruebas , Pronóstico , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Regulación hacia Arriba
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