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1.
bioRxiv ; 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38826434

RESUMEN

HCMV genes UL135 and UL138 play opposing roles regulating latency and reactivation in CD34+ human progenitor cells (HPCs). Using the THP-1 cell line model for latency and reactivation, we designed an RNA sequencing study to compare the transcriptional profile of HCMV infection in the presence and absence of these genes. The loss of UL138 results in elevated levels of viral gene expression and increased differentiation of cell populations that support HCMV gene expression and genome synthesis. The loss of UL135 results in diminished viral gene expression during an initial burst that occurs as latency is established and no expression of eleven viral genes from the ULb' region even following stimulation for differentiation and reactivation. Transcriptional network analysis revealed host transcription factors with potential to regulate the ULb' genes in coordination with pUL135. These results reveal roles for UL135 and UL138 in regulation of viral gene expression and potentially hematopoietic differentiation.

2.
NPJ Syst Biol Appl ; 10(1): 58, 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38806476

RESUMEN

Transcriptional regulation plays a crucial role in determining cell fate and disease, yet inferring the key regulators from gene expression data remains a significant challenge. Existing methods for estimating transcription factor (TF) activity often rely on static TF-gene interaction databases and cannot adapt to changes in regulatory mechanisms across different cell types and disease conditions. Here, we present a new algorithm - Transcriptional Inference using Gene Expression and Regulatory data (TIGER) - that overcomes these limitations by flexibly modeling activation and inhibition events, up-weighting essential edges, shrinking irrelevant edges towards zero through a sparse Bayesian prior, and simultaneously estimating both TF activity levels and changes in the underlying regulatory network. When applied to yeast and cancer TF knock-out datasets, TIGER outperforms comparable methods in terms of prediction accuracy. Moreover, our application of TIGER to tissue- and cell-type-specific RNA-seq data demonstrates its ability to uncover differences in regulatory mechanisms. Collectively, our findings highlight the utility of modeling context-specific regulation when inferring transcription factor activities.


Asunto(s)
Algoritmos , Biología Computacional , Redes Reguladoras de Genes , Factores de Transcripción , Redes Reguladoras de Genes/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Humanos , Biología Computacional/métodos , Teorema de Bayes , Regulación de la Expresión Génica/genética , Saccharomyces cerevisiae/genética , Neoplasias/genética
3.
PLoS One ; 18(11): e0294355, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37983277

RESUMEN

Salivary gland hypofunction is an adverse side effect associated with radiotherapy for head and neck cancer patients. This study delineated metabolic changes at acute, intermediate, and chronic radiation damage response stages in mouse salivary glands following a single 5 Gy dose. Ultra-high performance liquid chromatography-mass spectrometry was performed on parotid salivary gland tissue collected at 3, 14, and 30 days following radiation (IR). Pathway enrichment analysis, network analysis based on metabolite structural similarity, and network analysis based on metabolite abundance correlations were used to incorporate both metabolite levels and structural annotation. The greatest number of enriched pathways are observed at 3 days and the lowest at 30 days following radiation. Amino acid metabolism pathways, glutathione metabolism, and central carbon metabolism in cancer are enriched at all radiation time points across different analytical methods. This study suggests that glutathione and central carbon metabolism in cancer may be important pathways in the unresolved effect of radiation treatment.


Asunto(s)
Neoplasias de Cabeza y Cuello , Xerostomía , Animales , Ratones , Humanos , Glándulas Salivales/metabolismo , Glándula Parótida/efectos de la radiación , Neoplasias de Cabeza y Cuello/radioterapia , Neoplasias de Cabeza y Cuello/metabolismo , Carbono/metabolismo , Glutatión/metabolismo , Xerostomía/metabolismo
4.
bioRxiv ; 2023 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-37961132

RESUMEN

Merkel Cell Carcinoma (MCC) is a highly aggressive neuroendocrine cutaneous malignancy arising from either ultraviolet-induced mutagenesis or Merkel cell polyomavirus (MCPyV) integration. It is the only known neuroendocrine tumor (NET) with a virus etiology. Despite extensive research, our understanding of the molecular mechanisms driving the transition from normal cells to MCC remains limited. To address this knowledge gap, we assessed the impact of inducible MCPyV T antigens into normal human fibroblasts by performing RNA sequencing. Our findings suggested that the WNT signaling pathway plays a critical role in the development of MCC. To test this model, we bioinformatically evaluated various perturbagens for their ability to reverse the MCC gene expression signature and identified pyrvinium pamoate, an FDA-approved anthelminthic drug known for its anti-tumor potential in multiple cancers. Leveraging transcriptomic, network, and molecular analyses, we found that pyrvinium effectively targets multiple MCC vulnerabilities. Specifically, pyrvinium not only reverses the neuroendocrine features of MCC by modulating canonical and non-canonical WNT signaling pathways but also inhibits cancer cell growth by activating the p53-mediated apoptosis pathway, disrupting mitochondrial function, and inducing endoplasmic reticulum (ER) stress. Pyrvinium also effectively inhibits tumor growth in an MCC mouse xenograft model. These findings offer new avenues for the development of therapeutic strategies for neuroendocrine cancer and highlight the utility of pyrvinium as a potential treatment for MCC.

5.
Genome Biol ; 24(1): 45, 2023 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-36894939

RESUMEN

Inference and analysis of gene regulatory networks (GRNs) require software that integrates multi-omic data from various sources. The Network Zoo (netZoo; netzoo.github.io) is a collection of open-source methods to infer GRNs, conduct differential network analyses, estimate community structure, and explore the transitions between biological states. The netZoo builds on our ongoing development of network methods, harmonizing the implementations in various computing languages and between methods to allow better integration of these tools into analytical pipelines. We demonstrate the utility using multi-omic data from the Cancer Cell Line Encyclopedia. We will continue to expand the netZoo to incorporate additional methods.


Asunto(s)
Redes Reguladoras de Genes , Neoplasias , Humanos , Algoritmos , Programas Informáticos , Multiómica , Biología Computacional/métodos
6.
J Cell Biol ; 222(5)2023 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-36828364

RESUMEN

Dendritic spines are the postsynaptic compartment of a neuronal synapse and are critical for synaptic connectivity and plasticity. A developmental precursor to dendritic spines, dendritic filopodia (DF), facilitate synapse formation by sampling the environment for suitable axon partners during neurodevelopment and learning. Despite the significance of the actin cytoskeleton in driving these dynamic protrusions, the actin elongation factors involved are not well characterized. We identified the Ena/VASP protein EVL as uniquely required for the morphogenesis and dynamics of DF. Using a combination of genetic and optogenetic manipulations, we demonstrated that EVL promotes protrusive motility through membrane-direct actin polymerization at DF tips. EVL forms a complex at nascent protrusions and DF tips with MIM/MTSS1, an I-BAR protein important for the initiation of DF. We proposed a model in which EVL cooperates with MIM to coalesce and elongate branched actin filaments, establishing the dynamic lamellipodia-like architecture of DF.


Asunto(s)
Actinas , Moléculas de Adhesión Celular , Proteínas de Microfilamentos , Seudópodos , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Espinas Dendríticas/metabolismo , Neuronas/metabolismo , Seudópodos/metabolismo , Sinapsis/metabolismo , Moléculas de Adhesión Celular/metabolismo , Proteínas de Microfilamentos/metabolismo
7.
Cancers (Basel) ; 14(9)2022 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-35565256

RESUMEN

Consumption of cruciferous vegetables, rich in the isothiocyanate glucoraphanin, is associated with reduced risk of tobacco-related cancers. Sulforaphane, released by hydrolysis of glucoraphanin, potently induces cytoprotective phase II enzymes. Sulforaphane decreased the incidence of oral cancer in the 4NQO carcinogenesis model. In residents of Qidong, China, broccoli seed and sprout extracts (BSSE) increased detoxification of air pollutants benzene and acrolein, also found in tobacco smoke. This randomized, crossover trial evaluated detoxification of tobacco carcinogens by the BSSE Avmacol® in otherwise healthy smokers. Participants were treated for 2 weeks with both low and higher-dose BSSE (148 µmol vs. 296 µmol of glucoraphanin daily), separated by a 2-week washout, with randomization to low-high vs. high-low sequence. The primary endpoint was detoxification of benzene, measured by urinary excretion of its mercapturic acid, SPMA. Secondary endpoints included bioavailability, detoxification of acrolein and crotonaldehyde, modulation by GST genotype, and toxicity. Forty-nine participants enrolled, including 26 (53%) females with median use of 20 cigarettes/day. Low and higher-dose BSSE showed a mean bioavailability of 11% and 10%, respectively. Higher-dose BSSE significantly upregulated urinary excretion of the mercapturic acids of benzene (p = 0.04), acrolein (p < 0.01), and crotonaldehyde (p = 0.02), independent of GST genotype. Retention and compliance were high resulting in early study completion. In conclusion, BSSE significantly upregulated detoxification of the tobacco carcinogens benzene, acrolein, and crotonaldehyde in current tobacco smokers.

8.
Diagnostics (Basel) ; 12(3)2022 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-35328229

RESUMEN

The microenvironment of solid tumors is dynamic and frequently contains pockets of low oxygen levels (hypoxia) surrounded by oxygenated tissue. Indeed, a compromised vasculature is a hallmark of the tumor microenvironment, creating both spatial gradients and temporal variability in oxygen availability. Notably, hypoxia associates with increased metastasis and poor survival in patients. Therefore, to aid therapeutic decisions and better understand hypoxia's role in cancer progression, it is critical to identify endogenous biomarkers of hypoxia to spatially phenotype oncogenic lesions in human tissue, whether precancerous, benign, or malignant. Here, we characterize the glucose transporter GLUT3/SLC2A3 as a biomarker of hypoxic prostate epithelial cells and prostate tumors. Transcriptomic analyses of non-tumorigenic, immortalized prostate epithelial cells revealed a highly significant increase in GLUT3 expression under hypoxia. Additionally, GLUT3 protein increased 2.4-fold in cultured hypoxic prostate cell lines and was upregulated within hypoxic regions of xenograft tumors, including two patient-derived xenografts (PDX). Finally, GLUT3 out-performs other established hypoxia markers; GLUT3 staining in PDX specimens detects 2.6-8.3 times more tumor area compared to a mixture of GLUT1 and CA9 antibodies. Therefore, given the heterogeneous nature of tumors, we propose adding GLUT3 to immunostaining panels when trying to detect hypoxic regions in prostate samples.

9.
Sci Rep ; 11(1): 23507, 2021 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-34873211

RESUMEN

The tumor suppressor gene adenomatous polyposis coli (APC) is the initiating mutation in approximately 80% of all colorectal cancers (CRC), underscoring the importance of aberrant regulation of intracellular WNT signaling in CRC development. Recent studies have found that early-onset CRC exhibits an increased proportion of tumors lacking an APC mutation. We set out to identify mechanisms underlying APC mutation-negative (APCmut-) CRCs. We analyzed data from The Cancer Genome Atlas to compare clinical phenotypes, somatic mutations, copy number variations, gene fusions, RNA expression, and DNA methylation profiles between APCmut- and APC mutation-positive (APCmut+) microsatellite stable CRCs. Transcriptionally, APCmut- CRCs clustered into two approximately equal groups. Cluster One was associated with enhanced mitochondrial activation. Cluster Two was strikingly associated with genetic inactivation or decreased RNA expression of the WNT antagonist RNF43, increased expression of the WNT agonist RSPO3, activating mutation of BRAF, or increased methylation and decreased expression of AXIN2. APCmut- CRCs exhibited evidence of increased immune cell infiltration, with significant correlation between M2 macrophages and RSPO3. APCmut- CRCs comprise two groups of tumors characterized by enhanced mitochondrial activation or increased sensitivity to extracellular WNT, suggesting that they could be respectively susceptible to inhibition of these pathways.


Asunto(s)
Proteína de la Poliposis Adenomatosa del Colon/genética , Poliposis Adenomatosa del Colon/genética , Neoplasias Colorrectales/genética , Genes APC/fisiología , Repeticiones de Microsatélite/genética , Mutación/genética , Neoplasias Colorrectales/patología , Variaciones en el Número de Copia de ADN/genética , Metilación de ADN/genética , Progresión de la Enfermedad , Humanos , Inestabilidad de Microsatélites , Procesos Neoplásicos , Fenotipo , Regiones Promotoras Genéticas/genética , Vía de Señalización Wnt/genética
10.
Cell Rep ; 35(13): 109293, 2021 06 29.
Artículo en Inglés | MEDLINE | ID: mdl-34192535

RESUMEN

While the immediate and transitory response of breast cancer cells to pathological stiffness in their native microenvironment has been well explored, it remains unclear how stiffness-induced phenotypes are maintained over time after cancer cell dissemination in vivo. Here, we show that fibrotic-like matrix stiffness promotes distinct metastatic phenotypes in cancer cells, which are preserved after transition to softer microenvironments, such as bone marrow. Using differential gene expression analysis of stiffness-responsive breast cancer cells, we establish a multigenic score of mechanical conditioning (MeCo) and find that it is associated with bone metastasis in patients with breast cancer. The maintenance of mechanical conditioning is regulated by RUNX2, an osteogenic transcription factor, established driver of bone metastasis, and mitotic bookmarker that preserves chromatin accessibility at target gene loci. Using genetic and functional approaches, we demonstrate that mechanical conditioning maintenance can be simulated, repressed, or extended, with corresponding changes in bone metastatic potential.


Asunto(s)
Neoplasias Óseas/secundario , Neoplasias de la Mama/patología , Neoplasias de la Mama/fisiopatología , Fenómenos Biomecánicos , Médula Ósea/patología , Línea Celular Tumoral , Núcleo Celular/metabolismo , Subunidad alfa 1 del Factor de Unión al Sitio Principal/metabolismo , Matriz Extracelular/metabolismo , Femenino , Humanos , Mecanotransducción Celular , Invasividad Neoplásica , Microambiente Tumoral
11.
Physiol Genomics ; 53(3): 85-98, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33522389

RESUMEN

Radiation therapy for head and neck cancer causes damage to the surrounding salivary glands, resulting in salivary gland hypofunction and xerostomia. Current treatments do not provide lasting restoration of salivary gland function following radiation; therefore, a new mechanistic understanding of the radiation-induced damage response is necessary for identifying therapeutic targets. The purpose of the present study was to investigate the metabolic phenotype of radiation-induced damage in parotid salivary glands by integrating transcriptomic and metabolomic data. Integrated data were then analyzed to identify significant gene-metabolite interactions. Mice received a single 5 Gy dose of targeted head and neck radiation. Parotid tissue samples were collected 5 days following treatment for RNA sequencing and metabolomics analysis. Altered metabolites and transcripts significantly converged on a specific region in the metabolic reaction network. Both integrative pathway enrichment using rank-based statistics and network analysis highlighted significantly coordinated changes in glutathione metabolism, energy metabolism (TCA cycle and thermogenesis), peroxisomal lipid metabolism, and bile acid production with radiation. Integrated changes observed in energy metabolism suggest that radiation induces a mitochondrial dysfunction phenotype. These findings validated previous pathways involved in the radiation-damage response, such as altered energy metabolism, and identified robust signatures in salivary glands, such as reduced glutathione metabolism, that may be driving salivary gland dysfunction.


Asunto(s)
Perfilación de la Expresión Génica/métodos , Neoplasias de Cabeza y Cuello/radioterapia , Metabolómica/métodos , Traumatismos Experimentales por Radiación/genética , Glándulas Salivales/efectos de la radiación , Animales , Redes Reguladoras de Genes/efectos de la radiación , Humanos , Ratones , Mapas de Interacción de Proteínas/genética , Mapas de Interacción de Proteínas/efectos de la radiación , Traumatismos Experimentales por Radiación/metabolismo , Glándulas Salivales/metabolismo , Glándulas Salivales/fisiopatología , Transducción de Señal/genética , Transducción de Señal/efectos de la radiación , Xerostomía/genética , Xerostomía/metabolismo , Xerostomía/fisiopatología
12.
Mol Cancer Ther ; 19(9): 1809-1821, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32753387

RESUMEN

Despite significant progress in understanding the genetic landscape of T-cell acute lymphoblastic leukemia (T-ALL), the discovery of novel therapeutic targets has been difficult. Our results demonstrate that the levels of PIM1 protein kinase is elevated in early T-cell precursor ALL (ETP-ALL) but not in mature T-ALL primary samples. Small-molecule PIM inhibitor (PIMi) treatment decreases leukemia burden in ETP-ALL. However, treatment of animals carrying ETP-ALL with PIMi was not curative. To model other pathways that could be targeted to complement PIMi activity, HSB-2 cells, previously characterized as a PIMi-sensitive T-ALL cell line, were grown in increasing doses of PIMi. Gene set enrichment analysis of RNA sequencing data and functional enrichment of network modules demonstrated that the HOXA9, mTOR, MYC, NFκB, and PI3K-AKT pathways were activated in HSB-2 cells after long-term PIM inhibition. Reverse phase protein array-based pathway activation mapping demonstrated alterations in the mTOR, PI3K-AKT, and NFκB pathways, as well. PIMi-tolerant HSB-2 cells contained phosphorylated RelA-S536 consistent with activation of the NFκB pathway. The combination of NFκB and PIMis markedly reduced the proliferation in PIMi-resistant leukemic cells showing that this pathway plays an important role in driving the growth of T-ALL. Together these results demonstrate key pathways that are activated when HSB-2 cell line develop resistance to PIMi and suggest pathways that can be rationally targeted in combination with PIM kinases to inhibit T-ALL growth.


Asunto(s)
Resistencia a Antineoplásicos , Perfilación de la Expresión Génica/métodos , Redes Reguladoras de Genes/efectos de los fármacos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/administración & dosificación , Proteínas Proto-Oncogénicas c-pim-1/genética , Animales , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Proteínas de Homeodominio/genética , Humanos , Ratones , FN-kappa B/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-pim-1/antagonistas & inhibidores , Análisis de Secuencia de ARN , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/genética , Regulación hacia Arriba/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto
13.
Front Genet ; 11: 603264, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33519907

RESUMEN

The use of biological networks such as protein-protein interaction and transcriptional regulatory networks is becoming an integral part of genomics research. However, these networks are not static, and during phenotypic transitions like disease onset, they can acquire new "communities" (or highly interacting groups) of genes that carry out cellular processes. Disease communities can be detected by maximizing a modularity-based score, but since biological systems and network inference algorithms are inherently noisy, it remains a challenge to determine whether these changes represent real cellular responses or whether they appeared by random chance. Here, we introduce Constrained Random Alteration of Network Edges (CRANE), a method for randomizing networks with fixed node strengths. CRANE can be used to generate a null distribution of gene regulatory networks that can in turn be used to rank the most significant changes in candidate disease communities. Compared to other approaches, such as consensus clustering or commonly used generative models, CRANE emulates biologically realistic networks and recovers simulated disease modules with higher accuracy. When applied to breast and ovarian cancer networks, CRANE improves the identification of cancer-relevant GO terms while reducing the signal from non-specific housekeeping processes.

14.
Sci Rep ; 9(1): 12766, 2019 09 04.
Artículo en Inglés | MEDLINE | ID: mdl-31484939

RESUMEN

Genetic alterations are essential for cancer initiation and progression. However, differentiating mutations that drive the tumor phenotype from mutations that do not affect tumor fitness remains a fundamental challenge in cancer biology. To better understand the impact of a given mutation within cancer, RNA-sequencing data was used to categorize mutations based on their allelic expression. For this purpose, we developed the MAXX (Mutation Allelic Expression Extractor) software, which is highly effective at delineating the allelic expression of both single nucleotide variants and small insertions and deletions. Results from MAXX demonstrated that mutations can be separated into three groups based on their expression of the mutant allele, lack of expression from both alleles, or expression of only the wild-type allele. By taking into consideration the allelic expression patterns of genes that are mutated in PDAC, it was possible to increase the sensitivity of widely used driver mutation detection methods, as well as identify subtypes that have prognostic significance and are associated with sensitivity to select classes of therapeutic agents in cell culture. Thus, differentiating mutations based on their mutant allele expression via MAXX represents a means to parse somatic variants in tumor genomes, helping to elucidate a gene's respective role in cancer.


Asunto(s)
Alelos , Bases de Datos de Ácidos Nucleicos , Regulación Neoplásica de la Expresión Génica , Genoma Humano , Mutación , Neoplasias , Programas Informáticos , Humanos , Neoplasias/genética , Neoplasias/metabolismo
15.
Cancer Med ; 8(2): 617-628, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30652422

RESUMEN

It has been previously reported that ursodeoxycholic acid (UDCA), a therapeutic bile acid, reduced risk for advanced colorectal adenoma in men but not women. Interactions between the gut microbiome and fecal bile acid composition as a factor in colorectal cancer neoplasia have been postulated but evidence is limited to small cohorts and animal studies. Using banked stool samples collected as part of a phase III randomized clinical trial of UDCA for the prevention of colorectal adenomatous polyps, we compared change in the microbiome composition after a 3-year intervention in a subset of participants randomized to oral UDCA at 8-10 mg/kg of body weight per day (n = 198) or placebo (n = 203). Study participants randomized to UDCA experienced compositional changes in their microbiome that were statistically more similar to other individuals in the UDCA arm than to those in the placebo arm. This reflected a UDCA-associated shift in microbial community composition (P < 0.001), independent of sex, with no evidence of a UDCA effect on microbial richness (P > 0.05). These UDCA-associated shifts in microbial community distance metrics from baseline to end-of-study were not associated with risk of any or advanced adenoma (all P > 0.05) in men or women. Separate analyses of microbial networks revealed an overrepresentation of Faecalibacterium prausnitzii in the post-UDCA arm and an inverse relationship between F prausnitzii and Ruminococcus gnavus. In men who received UDCA, the overrepresentation of F prausnitzii and underrepresentation of R gnavus were more prominent in those with no adenoma recurrence at follow-up compared to men with recurrence. This relationship was not observed in women. Daily UDCA use modestly influences the relative abundance of microbial species in stool and affects the microbial network composition with suggestive evidence for sex-specific effects of UDCA on stool microbial community composition as a modifier of colorectal adenoma risk.


Asunto(s)
Adenoma/microbiología , Neoplasias Colorrectales/microbiología , Microbioma Gastrointestinal/efectos de los fármacos , Ácido Ursodesoxicólico/farmacología , Anciano , Heces/microbiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo
16.
NPJ Syst Biol Appl ; 4: 25, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29977601

RESUMEN

Probing the dynamic control features of biological networks represents a new frontier in capturing the dysregulated pathways in complex diseases. Here, using patient samples obtained from a pancreatic islet transplantation program, we constructed a tissue-specific gene regulatory network and used the control centrality (Cc) concept to identify the high control centrality (HiCc) pathways, which might serve as key pathobiological pathways for Type 2 Diabetes (T2D). We found that HiCc pathway genes were significantly enriched with modest GWAS p-values in the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) study. We identified variants regulating gene expression (expression quantitative loci, eQTL) of HiCc pathway genes in islet samples. These eQTL genes showed higher levels of differential expression compared to non-eQTL genes in low, medium, and high glucose concentrations in rat islets. Among genes with highly significant eQTL evidence, NFATC4 belonged to four HiCc pathways. We asked if the expressions of T2D-associated candidate genes from GWAS and literature are regulated by Nfatc4 in rat islets. Extensive in vitro silencing of Nfatc4 in rat islet cells displayed reduced expression of 16, and increased expression of four putative downstream T2D genes. Overall, our approach uncovers the mechanistic connection of NFATC4 with downstream targets including a previously unknown one, TCF7L2, and establishes the HiCc pathways' relationship to T2D.

17.
NPJ Syst Biol Appl ; 4: 16, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29707235

RESUMEN

Complex traits and diseases like human height or cancer are often not caused by a single mutation or genetic variant, but instead arise from functional changes in the underlying molecular network. Biological networks are known to be highly modular and contain dense "communities" of genes that carry out cellular processes, but these structures change between tissues, during development, and in disease. While many methods exist for inferring networks and analyzing their topologies separately, there is a lack of robust methods for quantifying differences in network structure. Here, we describe ALPACA (ALtered Partitions Across Community Architectures), a method for comparing two genome-scale networks derived from different phenotypic states to identify condition-specific modules. In simulations, ALPACA leads to more nuanced, sensitive, and robust module discovery than currently available network comparison methods. As an application, we use ALPACA to compare transcriptional networks in three contexts: angiogenic and non-angiogenic subtypes of ovarian cancer, human fibroblasts expressing transforming viral oncogenes, and sexual dimorphism in human breast tissue. In each case, ALPACA identifies modules enriched for processes relevant to the phenotype. For example, modules specific to angiogenic ovarian tumors are enriched for genes associated with blood vessel development, and modules found in female breast tissue are enriched for genes involved in estrogen receptor and ERK signaling. The functional relevance of these new modules suggests that not only can ALPACA identify structural changes in complex networks, but also that these changes may be relevant for characterizing biological phenotypes.

18.
PLoS Pathog ; 13(10): e1006668, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29028833

RESUMEN

Merkel cell carcinoma (MCC) frequently contains integrated copies of Merkel cell polyomavirus DNA that express a truncated form of Large T antigen (LT) and an intact Small T antigen (ST). While LT binds RB and inactivates its tumor suppressor function, it is less clear how ST contributes to MCC tumorigenesis. Here we show that ST binds specifically to the MYC homolog MYCL (L-MYC) and recruits it to the 15-component EP400 histone acetyltransferase and chromatin remodeling complex. We performed a large-scale immunoprecipitation for ST and identified co-precipitating proteins by mass spectrometry. In addition to protein phosphatase 2A (PP2A) subunits, we identified MYCL and its heterodimeric partner MAX plus the EP400 complex. Immunoprecipitation for MAX and EP400 complex components confirmed their association with ST. We determined that the ST-MYCL-EP400 complex binds together to specific gene promoters and activates their expression by integrating chromatin immunoprecipitation with sequencing (ChIP-seq) and RNA-seq. MYCL and EP400 were required for maintenance of cell viability and cooperated with ST to promote gene expression in MCC cell lines. A genome-wide CRISPR-Cas9 screen confirmed the requirement for MYCL and EP400 in MCPyV-positive MCC cell lines. We demonstrate that ST can activate gene expression in a EP400 and MYCL dependent manner and this activity contributes to cellular transformation and generation of induced pluripotent stem cells.


Asunto(s)
Antígenos Virales de Tumores/metabolismo , Carcinoma de Células de Merkel/virología , Transformación Celular Viral/fisiología , ADN Helicasas/metabolismo , Proteínas de Unión al ADN/metabolismo , Regulación Neoplásica de la Expresión Génica/fisiología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Antígenos Transformadores de Poliomavirus/metabolismo , Carcinoma de Células de Merkel/genética , Carcinoma de Células de Merkel/metabolismo , Línea Celular Tumoral , Humanos , Immunoblotting , Inmunoprecipitación , Poliomavirus de Células de Merkel , Infecciones por Polyomavirus/complicaciones , Infecciones por Polyomavirus/genética , Infecciones por Polyomavirus/metabolismo , Infecciones Tumorales por Virus/complicaciones , Infecciones Tumorales por Virus/genética , Infecciones Tumorales por Virus/metabolismo
19.
PLoS Pathog ; 12(11): e1006020, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27880818

RESUMEN

Merkel cell polyomavirus (MCPyV) is an etiological agent of Merkel cell carcinoma (MCC), a highly aggressive skin cancer. The MCPyV small tumor antigen (ST) is required for maintenance of MCC and can transform normal cells. To gain insight into cellular perturbations induced by MCPyV ST, we performed transcriptome analysis of normal human fibroblasts with inducible expression of ST. MCPyV ST dynamically alters the cellular transcriptome with increased levels of glycolytic genes, including the monocarboxylate lactate transporter SLC16A1 (MCT1). Extracellular flux analysis revealed increased lactate export reflecting elevated aerobic glycolysis in ST expressing cells. Inhibition of MCT1 activity suppressed the growth of MCC cell lines and impaired MCPyV-dependent transformation of IMR90 cells. Both NF-κB and MYC have been shown to regulate MCT1 expression. While MYC was required for MCT1 induction, MCPyV-induced MCT1 levels decreased following knockdown of the NF-κB subunit RelA, supporting a synergistic activity between MCPyV and MYC in regulating MCT1 levels. Several MCC lines had high levels of MYCL and MYCN but not MYC. Increased levels of MYCL was more effective than MYC or MYCN in increasing extracellular acidification in MCC cells. Our results demonstrate the effects of MCPyV ST on the cellular transcriptome and reveal that transformation is dependent, at least in part, on elevated aerobic glycolysis.


Asunto(s)
Antígenos Transformadores de Poliomavirus/metabolismo , Carcinoma de Células de Merkel/virología , Transformación Celular Viral/fisiología , Glucólisis/genética , Neoplasias Cutáneas/virología , Carcinoma de Células de Merkel/metabolismo , Línea Celular , Biología Computacional , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica/fisiología , Humanos , Immunoblotting , Poliomavirus de Células de Merkel , Metabolómica , Reacción en Cadena en Tiempo Real de la Polimerasa , Neoplasias Cutáneas/metabolismo , Transfección
20.
Nucleic Acids Res ; 44(13): 6070-86, 2016 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-27280975

RESUMEN

Cell cycle (CC) and TP53 regulatory networks are frequently deregulated in cancer. While numerous genome-wide studies of TP53 and CC-regulated genes have been performed, significant variation between studies has made it difficult to assess regulation of any given gene of interest. To overcome the limitation of individual studies, we developed a meta-analysis approach to identify high confidence target genes that reflect their frequency of identification in independent datasets. Gene regulatory networks were generated by comparing differential expression of TP53 and CC-regulated genes with chromatin immunoprecipitation studies for TP53, RB1, E2F, DREAM, B-MYB, FOXM1 and MuvB. RNA-seq data from p21-null cells revealed that gene downregulation by TP53 generally requires p21 (CDKN1A). Genes downregulated by TP53 were also identified as CC genes bound by the DREAM complex. The transcription factors RB, E2F1 and E2F7 bind to a subset of DREAM target genes that function in G1/S of the CC while B-MYB, FOXM1 and MuvB control G2/M gene expression. Our approach yields high confidence ranked target gene maps for TP53, DREAM, MMB-FOXM1 and RB-E2F and enables prediction and distinction of CC regulation. A web-based atlas at www.targetgenereg.org enables assessing the regulation of any human gene of interest.


Asunto(s)
Proteína Forkhead Box M1/genética , Proteínas de Interacción con los Canales Kv/genética , Neoplasias/genética , Proteínas Represoras/genética , Proteína p53 Supresora de Tumor/genética , Ciclo Celular/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Factores de Transcripción E2F/genética , Proteína Forkhead Box M1/biosíntesis , Regulación Neoplásica de la Expresión Génica , Redes Reguladoras de Genes/genética , Humanos , Proteínas de Interacción con los Canales Kv/biosíntesis , Neoplasias/patología , Regiones Promotoras Genéticas , Proteínas Represoras/biosíntesis , Proteínas de Unión a Retinoblastoma/genética , Proteína p53 Supresora de Tumor/biosíntesis , Ubiquitina-Proteína Ligasas/genética
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