Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
2.
J Foot Ankle Surg ; 63(1): 92-96, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37709189

RESUMO

The objective of this cadaveric biomechanical study was to evaluate if the center-center surgical technique is a reliable and repeatable method of achieving proper syndesmotic reduction when using dynamic syndesmotic fixation. Nine fresh frozen above-knee cadaveric lower extremities were used. Computerized tomography (CT) scans were first obtained for each intact specimen as the baseline for comparison. A simulated complete syndesmotic disruption was created by transection of all deltoid and syndesmotic ligaments. Instability of the ankle was confirmed with stress imaging using fluoroscopy. Each unstable specimen was repaired using the center-center surgical technique with dynamic syndesmosis fixation. A series of measurements from the axial CT images of intact and repaired specimens were used to determine the anatomic distal tibiofibular relationships for comparison of changes from intact to postfixation. All radiographic measurements were performed by 4 independent foot and ankle surgeons. The level of inter-rater reliability for all the measurements was found to be "moderate" to "excellent" agreement (ICC value: 0.865-0.983, 95% confidence interval: 0.634-0.996). There was no statistical difference found between rotational alignment of native and postfixation (a/b: p = .843; b-a: p = .125; θ: p = .062). There was a statistical difference detected for lateral alignment at the center of fibularis incisura between native and postfixation (average: -0.6 ± 0.8 mm, range: -2.3 to 1.2 mm, p < .001). There was no statistical difference found for the anteroposterior translation alignment between native and postfixation (d/e: p = .251; f: p = .377). This study demonstrated the use of the center-center surgical technique as a viable and repeatable method for achieving anatomical reduction of the tibiofibular syndesmosis when used with dynamic fixation modalities.


Assuntos
Traumatismos do Tornozelo , Fíbula , Humanos , Projetos Piloto , Fíbula/cirurgia , Reprodutibilidade dos Testes , Traumatismos do Tornozelo/diagnóstico por imagem , Traumatismos do Tornozelo/cirurgia , Articulação do Tornozelo/diagnóstico por imagem , Articulação do Tornozelo/cirurgia , Cadáver
3.
EBioMedicine ; 83: 104216, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35986950

RESUMO

The tumour microenvironment (TME) imposes a major obstacle to infiltrating T-lymphocytes and suppresses their function. Several immune checkpoint proteins that interfere with ligand/receptor interactions and impede T-cell anti-tumour responses have been identified. Immunotherapies that block immune checkpoints have revolutionized the treatment paradigm for many patients with advanced-stage tumours. However, metabolic constraints and soluble factors that exist within the TME exacerbate the functional exhaustion of tumour-infiltrating T-cells. Here we review these multifactorial constraints and mechanisms - elevated immunosuppressive metabolites and enzymes, nutrient insufficiency, hypoxia, increased acidity, immense amounts of extracellular ATP and adenosine, dysregulated bioenergetic and purinergic signalling, and ionic imbalance - that operate in the TME and collectively suppress T-cell function. We discuss how scientific advances could help overcome the complex TME obstacles for tumour-infiltrating T-lymphocytes, aiming to stimulate further research for developing new therapeutic strategies by harnessing the full potential of the immune system in combating cancer.


Assuntos
Neoplasias , Linfócitos T , Adenosina , Trifosfato de Adenosina , Humanos , Proteínas de Checkpoint Imunológico , Imunoterapia , Ligantes , Neoplasias/patologia , Microambiente Tumoral
4.
Cell Mol Gastroenterol Hepatol ; 10(3): 601-622, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32416156

RESUMO

BACKGROUND & AIMS: Esophageal adenocarcinoma (EAC) develops from within Barrett's esophagus (BE) concomitant with gastroesophageal reflux disease (GERD). Wound healing processes and cellular transitions, such as epithelial-mesenchymal transitions, may contribute to the development of BE and the eventual migratory escape of metastatic cancer cells. Herein, we attempt to identify the genes underlying esophageal cellular transitions and their potential regulation by the low pH environments observed in GERD and commonly encountered by escaping cancer cells. METHODS: Small interfering RNA library screening and high-content imaging analysis outlined changes in BE high-grade dysplasia (HGD) and EAC cell morphologies after gene silencing. Gene expression microarray data and low pH exposures studies modeling GERD-associated pulses (pH 4.0, 10 min) and tumor microenvironments (pH 6.0, constant) were used. RESULTS: Statistical analysis of small interfering RNA screening data defined 207 genes (Z-score >2.0), in 12 distinct morphologic clusters, whose suppression significantly altered BE-HGD cell morphology. The most significant genes in this list included KIF11, RRM2, NUBP2, P66BETA, DUX1, UBE3A, ITGB8, GAS1, GPS1, and PRC1. Guided by gene expression microarray study data, both pulsatile and constant low pH exposures were observed to suppress the expression of GPS1 and RRM2 in a nonoverlapping temporal manner in both BE-HGD and EAC cells, with no changes observed in squamous esophageal cells. Functional studies uncovered that GPS1 and RRM2 contributed to amoeboid and mesenchymal cellular transitions, respectively, as characterized by differential rates of cell motility, pseudopodia formation, and altered expression of the mesenchymal markers vimentin and E-cadherin. CONCLUSIONS: Collectively, we have shown that low pH microenvironments associated with GERD, and tumor invasive edges, can modulate the expression of genes that triggered esophageal cellular transitions potentially critical to colonization and invasion.


Assuntos
Adenocarcinoma/genética , Esôfago de Barrett/patologia , Transformação Celular Neoplásica/genética , Neoplasias Esofágicas/genética , Refluxo Gastroesofágico/complicações , Regulação Neoplásica da Expressão Gênica , Adenocarcinoma/patologia , Linhagem Celular Tumoral , Movimento Celular , Transformação Celular Neoplásica/patologia , Progressão da Doença , Células Epiteliais/química , Células Epiteliais/patologia , Mucosa Esofágica/química , Mucosa Esofágica/citologia , Mucosa Esofágica/patologia , Neoplasias Esofágicas/patologia , Refluxo Gastroesofágico/patologia , Perfilação da Expressão Gênica , Humanos , Concentração de Íons de Hidrogênio , Microscopia Intravital , Análise de Sequência com Séries de Oligonucleotídeos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Imagem com Lapso de Tempo , Microambiente Tumoral/genética
5.
Cell Mol Gastroenterol Hepatol ; 5(4): 569-590, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29930979

RESUMO

BACKGROUND & AIMS: Effective therapeutic approaches are urgently required to tackle the alarmingly poor survival outcomes in esophageal adenocarcinoma (EAC) patients. EAC originates from within the intestinal-type metaplasia, Barrett's esophagus, a condition arising on a background of gastroesophageal reflux disease and associated inflammation. METHODS: This study used a druggable genome small interfering RNA (siRNA) screening library of 6022 siRNAs in conjunction with bioinformatics platforms, genomic studies of EAC tissues, somatic variation data of EAC from The Cancer Genome Atlas data of EAC, and pathologic and functional studies to define novel EAC-associated, and targetable, immune factors. RESULTS: By using a druggable genome library we defined genes that sustain EAC cell growth, which included an unexpected immunologic signature. Integrating Cancer Genome Atlas data with druggable siRNA targets showed a striking concordance and an EAC-specific gene amplification event associated with 7 druggable targets co-encoded at Chr6p21.1. Over-representation of immune pathway-associated genes supporting EAC cell growth included leukemia inhibitory factor, complement component 1, q subcomponent A chain (C1QA), and triggering receptor expressed on myeloid cells 2 (TREM2), which were validated further as targets sharing downstream signaling pathways through genomic and pathologic studies. Finally, targeting the triggering receptor expressed on myeloid cells 2-, C1q-, and leukemia inhibitory factor-activated signaling pathways (TYROBP-spleen tyrosine kinase and JAK-STAT3) with spleen tyrosine kinase and Janus-activated kinase inhibitor fostamatinib R788 triggered EAC cell death, growth arrest, and reduced tumor burden in NOD scid gamma mice. CONCLUSIONS: These data highlight a subset of genes co-identified through siRNA targeting and genomic studies of expression and somatic variation, specifically highlighting the contribution that immune-related factors play in support of EAC development and suggesting their suitability as targets in the treatment of EAC.

7.
Sci Rep ; 6: 32638, 2016 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-27586588

RESUMO

Barrett's oesophagus (BO), an intestinal-type metaplasia (IM), typically arising in conjunction with gastro-oesophageal reflux disease, is a prominent risk factor for the development of oesophageal adenocarcinoma (OAC). The molecular similarities between IM and normal intestinal tissues are ill-defined. Consequently, the contribution of intestine-enriched factors expressed within BO to oncogenesis is unclear. Herein, using transcriptomics we define the intestine-enriched genes expressed in meta-profiles of BO and OAC. Interestingly, 77% of the genes differentially expressed in a meta-profile of BO were similarly expressed in intestinal tissues. Furthermore, 85% of this intestine-like signature was maintained upon transition to OAC. Gene networking analysis of transcription factors within this signature revealed a network centred upon NR5A2, GATA6 and FOXA2, whose over-expression was determined in a cohort of BO and OAC patients. Simulated acid reflux was observed to induce the expression of both NR5A2 and GATA6. Using siRNA-mediated silencing and an NR5A2 antagonist we demonstrate that NR5A2-mediated cancer cell survival is facilitated through augmentation of GATA6 and anti-apoptotic factor BCL-XL levels. Abrogation of NR5A2-GATA6 expression in conjunction with BCL-XL co-silencing resulted in synergistically increased sensitivity to chemotherapeutics and photo-dynamic therapeutics. These findings characterize the intestine-like signature associated with IM which may have important consequences to adenocarcinogenesis.


Assuntos
Adenocarcinoma/genética , Adenocarcinoma/patologia , Esôfago de Barrett/genética , Esôfago de Barrett/patologia , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Genoma Humano , Mucosa Intestinal/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Apoptose/genética , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Fator de Transcrição GATA6/metabolismo , Ácido Gástrico/metabolismo , Refluxo Gastroesofágico , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Inativação Gênica , Humanos , Reprodutibilidade dos Testes , Proteína bcl-X/metabolismo
8.
J Immunol ; 186(4): 2462-71, 2011 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-21220698

RESUMO

Helicobacter pylori causes chronic gastritis, peptic ulcers, and gastric carcinoma. Gastric epithelial cells provide the first point of contact between H. pylori and the host. TLRs present on these cells recognize various microbial products, resulting in the initiation of innate immunity. Although previous reports investigated TLR signaling in response to intact H. pylori, the specific contribution of H. pylori LPS with regard to functional genomics and cell-signaling events has not been defined. This study set out to define downstream signaling components and altered gene expression triggered by H. pylori LPS and to investigate the role of the signaling protein tribbles 3 (TRIB3) during the TLR-mediated response to H. pylori LPS. Cotransfections using small interfering RNA and dominant-negative constructs demonstrated that H. pylori LPS functions as a classic TLR2 ligand by signaling through pathways involving the key TLR signaling components MyD88 adaptor-like, MyD88, IRAK1, IRAK4, TNFR-associated factor 6, IκB kinase ß, and IκBα. Microarray analysis, real-time PCR, and ELISA revealed the induction of a discrete pattern of chemokines as a direct effect of LPS:TLR2 signaling. H. pylori infection was associated with decreased expression of TRIB3 in human gastric epithelial cell lines and tissue samples. Additionally, H. pylori decreased expression of C/EBP homologous protein and activating transcription factor 4, the transcription factors involved in the induction of TRIB3 expression. Furthermore, knockdown of TRIB3 and C/EBP homologous protein enhanced TLR2-mediated NF-κB activation and chemokine induction in response to H. pylori LPS. Thus, modulation of TRIB3 by H. pylori and/or its products may be an important mechanism during H. pylori-associated pathogenesis.


Assuntos
Proteínas de Ciclo Celular/fisiologia , Helicobacter pylori/imunologia , Lipopolissacarídeos/fisiologia , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Repressoras/fisiologia , Transdução de Sinais/imunologia , Receptor 2 Toll-Like/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/biossíntese , Linhagem Celular , Linhagem Celular Tumoral , Quimiocinas/biossíntese , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/metabolismo , Regulação para Baixo/genética , Regulação para Baixo/imunologia , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Células HEK293 , Humanos , Imunidade Inata/genética , Interleucina-8/biossíntese , Interleucina-8/genética , Lipopolissacarídeos/isolamento & purificação , NF-kappa B/metabolismo , Regiões Promotoras Genéticas/imunologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/biossíntese , Transdução de Sinais/genética , Receptor 2 Toll-Like/fisiologia , Regulação para Cima/genética , Regulação para Cima/imunologia
9.
Carcinogenesis ; 31(5): 936-45, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20139130

RESUMO

Reflux of gastroduodenal contents and consequent inflammatory responses are associated with the development of Barrett's oesophagus (BO) and the promotion of oesophageal adenocarcinoma (OAC). Deregulation of inflammatory processes is a hallmark of oesophageal cancer. In this study, we aimed to investigate (i) the transcriptional responses to deoxycholic acid (DCA) in cell lines representative of either end of the oesophageal cancer sequence, (ii) the expression of DCA-regulated genes in data charting oesophageal carcinogenesis and (iii) the impact of these genes on oesophageal inflammatory signalling. Gene expression microarrays were utilized to demonstrate differential transcriptional responses between squamous (HET-1A) and adenomatous (SKGT4) cell lines exposed to DCA. Differential basal and DCA-inducible expression of cytokines such as interleukin (IL) 8 was observed between both cell types. A cohort of DCA-regulated genes specific to each cell type was identified in microarray experimentation and subsequently validated. Cell type-specific genes included TRB3, CXCL14, GDF15 and LIF in HET-1A cells, with COX2-, ESM1-, URHF1- and IL1alpha-and IL1beta-specific expression in SKGT4 cells. Over 30% of the genes altered in BO and OAC were shown to be regulated by DCA utilizing an integrative genomic approach. One such gene, tribbles-homology-3 (TRB3) was induced specifically in HET-1A cells, absent in SKGT4 cells and decreased in BO samples in silico and in vivo. Inhibition and re-introduction of TRB3 in HET-1A and SKGT4 cells, respectively, demonstrated the ability of TRB3 to regulate inflammatory signalling through nuclear factor-kappaB. This study identifies mechanisms through which bile acids such as DCA, in conjunction with the loss of key signalling molecules, could regulate oesophageal metaplasticity.


Assuntos
Esôfago de Barrett/etiologia , Proteínas de Ciclo Celular/genética , Ácido Desoxicólico/farmacologia , Esôfago/patologia , Interleucina-8/análise , NF-kappa B/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Repressoras/genética , Elementos de Resposta/fisiologia , Esôfago de Barrett/genética , Esôfago de Barrett/patologia , Proteínas de Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Regulação para Baixo , Esôfago/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Genômica , Humanos , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Repressoras/fisiologia , Transdução de Sinais
10.
Ann Surg ; 250(5): 729-37, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19801928

RESUMO

OBJECTIVE: This study explored gene expression differences in predicting response to chemoradiotherapy in esophageal cancer. PURPOSE: A major pathological response to neoadjuvant chemoradiation is observed in about 40% of esophageal cancer patients and is associated with favorable outcomes. However, patients with tumors of similar histology, differentiation, and stage can have vastly different responses to the same neoadjuvant therapy. This dichotomy may be due to differences in the molecular genetic environment of the tumor cells. BACKGROUND DATA: Diagnostic biopsies were obtained from a training cohort of esophageal cancer patients (13), and extracted RNA was hybridized to genome expression microarrays. The resulting gene expression data was verified by qRT-PCR. In a larger, independent validation cohort (27), we examined differential gene expression by qRT-PCR. The ability of differentially-regulated genes to predict response to therapy was assessed in a multivariate leave-one-out cross-validation model. RESULTS: Although 411 genes were differentially expressed between normal and tumor tissue, only 103 genes were altered between responder and non-responder tumor; and 67 genes differentially expressed >2-fold. These included genes previously reported in esophageal cancer and a number of novel genes. In the validation cohort, 8 of 12 selected genes were significantly different between the response groups. In the predictive model, 5 of 8 genes could predict response to therapy with 95% accuracy in a subset (74%) of patients. CONCLUSIONS: This study has identified a gene microarray pattern and a set of genes associated with response to neoadjuvant chemoradiation in esophageal cancer. The potential of these genes as biomarkers of response to treatment warrants further investigation.


Assuntos
Neoplasias Esofágicas/genética , Perfilação da Expressão Gênica , Análise de Sequência com Séries de Oligonucleotídeos , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Biópsia , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/radioterapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Neoadjuvante , Resultado do Tratamento
11.
Carcinogenesis ; 27(2): 319-27, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16113055

RESUMO

The development of gastro-oesophageal reflux disease (GORD) is known to be a causative risk factor in the evolution of adenocarcinoma of the oesophagus. The major component of this reflux is gastric acid. However, the impact of low pH on gene expression has not been extensively studied in oesophageal cells. This study utilizes a transcriptomic and bioinformatic approach to assess regulation of gene expression in response to low pH. In more detail, oesophageal adenocarcinoma cell lines were exposed to a range of pH environments. Affymetrix microarrays were used for gene-expression analysis and results were validated using cycle limitation and real-time RT-PCR analysis, as well as northern and western blotting. Comparative promoter transcription factor binding site (TFBS) analysis (MatInspector) of hierarchically clustered gene-expression data was employed to identify the elements which may co-ordinately regulate individual gene clusters. Initial experiments demonstrated maximal induction of EGR1 gene expression at pH 6.5. Subsequent array experimentation revealed significant induction of gene expression from such functional categories as DNA damage response (EGR1-4, ATF3) and cell-cycle control (GADD34, GADD45, p57). Changes in expression of EGR1, EGR3, ATF3, MKP-1, FOSB, CTGF and CYR61 were verified in separate experiments and in a variety of oesophageal cell lines. TFBS analysis of promoters identified transcription factors that may co-ordinately regulate gene-expression clusters, Cluster 1: Oct-1, AP4R; Cluster 2: NF-kB, EGRF; Cluster 3: IKRS, AP-1F. Low pH has the ability to induce genes and pathways which can provide an environment suitable for the progression of malignancy. Further functional analysis of the genes and clusters identified in this low pH study is likely to lead to new insights into the pathogenesis and therapeutics of GORD and oesophageal cancer.


Assuntos
Neoplasias Esofágicas/genética , Neoplasias Esofágicas/fisiopatologia , Esôfago/fisiologia , Refluxo Gastroesofágico/complicações , Regulação Neoplásica da Expressão Gênica , Northern Blotting , Western Blotting , Técnicas de Cultura de Células , Ciclo Celular , Linhagem Celular Tumoral , Biologia Computacional , Dano ao DNA , Esôfago/citologia , Perfilação da Expressão Gênica , Humanos , Concentração de Íons de Hidrogênio , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas , Reação em Cadeia da Polimerase Via Transcriptase Reversa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA