Biallelic inactivating mutations of the transcription factor 1 gene (TCF1), encoding hepatocyte nuclear factor 1a (HNF1a), were identified in 50% of hepatocellular adenomas (HCA) phenotypically characterized by a striking steatosis. To understand the molecular basis of this aberrant lipid storage, we performed a microarray transcriptome analysis validated by quantitative RT-PCR, western-blotting and lipid profiling. In mutated HCA, we showed a repression of gluconeogenesis coordinated with an activation of glycolysis, citrate shuttle and fatty acid synthesis predicting elevated rates of lipogenesis. Moreover, the strong dowregulation of L-FABP suggests that impaired fatty acid trafficking may also contribute to the fatty phenotype. In addition, transcriptional profile analysis of the observed deregulated genes in non-HNF1a-mutated HCA as well as in non-tumor livers allowed us to define a specific signature of the HNF1a-mutated HCA. In theses tumors, lipid composition was dramatically modified according to the transcriptional deregulations identified in the fatty acid synthetic pathway. Surprisingly, lipogenesis activation did not operate through SREBP-1 and ChREBP that were repressed. We conclude that steatosis in HNF1a-mutated HCA results mainly from an aberrant promotion of lipogenesis that is linked to HNF1a inactivation and that is independent of both SREBP-1 and ChREBP activation. Finally, our findings have potential clinical implications since lipogenesis can be efficiently inhibited by targeted therapies.
HNF1alpha inactivation promotes lipogenesis in human hepatocellular adenoma independently of SREBP-1 and carbohydrate-response element-binding protein (ChREBP) activation.
Sex, Specimen part, Disease
View SamplesFocal nodular hyperplasias (FNHs) are benign liver lesions considered to be a hyperplastic response to increased blood flow in otherwise normal liver. In contrast, FNH-like nodules occur in cirrhotic liver but share similar histopathological features. To better understand the pathophysiology of FNH, we performed a transcriptomic analysis. Methods: Affymetrix and cDNA microarrays were used to compare gene expression in eight FNHs with that in tissue from six normal livers. Selected genes were validated with quantitative RT-PCR in 70 benign liver tumors including adenomas and cirrhotic and FNH-like lesions. Results: Among the deregulated genes in FNHs, 19 were physiologically zonated in the normal liver lobule. All six periveinous genes were up-regulated in FNH, whereas 13 genes normally expressed in the periportal area were down-regulated. Immunohistochemistry revealed that glutamine synthetase was markedly overexpressed, forming anastomosed areas usually centered on visible veins. -catenin mRNA was slightly but significantly overexpressed, as were several known -catenin target genes. Moreover, activated hypophosphorylated -catenin protein accumulated in FNH in the absence of activating mutations. These results suggest zonated activation of the -catenin pathway specifically in FNH, whereas the other benign hepatocellular tumors, including FNH-like lesions, demonstrated an entirely different pattern of -catenin expression. Conclusions: In FNH, increased expression of the -catenin pathway was restricted to enlarged periveinous areas, which may explain the slight polyclonal over-proliferation of hepatocytes at the origin of the lesion. FNH-like nodules may have a different pathogenetic origin.
The beta-catenin pathway is activated in focal nodular hyperplasia but not in cirrhotic FNH-like nodules.
Sex, Specimen part, Disease
View SamplesInflammatory hepatocellular adenomas (IHCA) are benign liver tumours defined by the presence of inflammatory infiltrates and by the elevated expression of inflammatory proteins in tumour hepatocytes1,2. Here we show a striking activation of the IL6 signalling pathway in this tumour type, and sequencing candidate genes pinpointed this response to somatic gain-of-function mutations in the IL6ST gene that encodes the signalling co-receptor gp130. Indeed, ~70% of IHCA harbour small in-frame deletions that target the binding site of gp130 for IL6, and expression of the most frequent gp130 mutant, Delta-STVY190, in hepatocellular cells activates STAT3 in absence of ligand. Further, analysis of hepatocellular carcinomas revealed rare gp130 alterations always accompanied by -catenin-activating mutations, suggesting a cooperative effect of these signalling pathways in the malignant conversion of hepatocytes. The recurrent gain-of-function gp130 mutations in these human hepatocellular adenomas explains their inflammatory phenotype, and suggest that similar alterations may occur in other inflammatory epithelial tumours with STAT3 activation.
Frequent in-frame somatic deletions activate gp130 in inflammatory hepatocellular tumours.
Sex, Specimen part, Disease
View SamplesHepatocellular carcinoma (HCC) is ranked second in cancer-associated deaths worldwide. Most cases of HCC are secondary to either a viral hepatitis infection (hepatitis B or C) or cirrhosis (alcoholism being the most common cause of hepatic cirrhosis). It is a complex and heterogeneous tumor due to activation of multiple cellular pathways and molecular alterations.
Exome sequencing of hepatocellular carcinomas identifies new mutational signatures and potential therapeutic targets.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesHepatoblastoma, the most common pediatric liver cancer, is tightly linked to excessive Wnt/�-catenin signaling. Microarray analysis identified two tumor subclasses resembling distinct phases of liver development, and a 16-gene signature discriminated invasive and metastatic hepatoblastomas, and predicted prognosis with high accuracy. <br></br>
Hepatic stem-like phenotype and interplay of Wnt/beta-catenin and Myc signaling in aggressive childhood liver cancer.
Sex, Age, Specimen part, Disease, Disease stage, Subject
View SamplesThe Adar1 deaminase inactive mutant mouse tissue samples were obtain from the Walkley lab as described in http://www.ncbi.nlm.nih.gov/pubmed/26275108. We performed mmPCR-seq on the samples and measured the editing levels of. Overall design: Fetal mRNA profiles of E12.5 wild type (WT) and ADAR E861A mutant mice were generated by deep sequencing using Illumina HiSeq 2000.
Dynamic landscape and regulation of RNA editing in mammals.
Specimen part, Cell line, Subject
View SamplesGPR146 is a susceptible gene associated with plasma cholesterol levels in humans, its physiological and molecular functions have not been fully characherized. In this study, we generated Gpr146 whole-body knockout mice and found that depletion of GPR146 led to substantilly reduced plasma total cholesterol levels.
GPR146 Deficiency Protects against Hypercholesterolemia and Atherosclerosis.
Specimen part
View SamplesIn order to study parent-of-origin effects on gene expression, we performed RNAseq analysis (100bp single end reads) of 165 children who formed part of mother/father/child trios where genotype data was available from the HapMap and/or 1000 Genomes Projects. Based on phased genotypes at heterozygous SNP positions, we generated allelic counts for expression of the maternal and paternal alleles in each individual. This analysis reveals significant bias in the expression of the parental alleles for dozens of genes, including both previously known and novel imprinted transcripts. Overall design: This submission contains RNAseq data from 165 children from mother/father/child trios studied as part of the 1000 genomes and/or HapMap projects. We provide raw fastq format reads, and processed read counts per gene. Allelic count information can be provided by directly contacting the authors.
RNA-Seq in 296 phased trios provides a high-resolution map of genomic imprinting.
Specimen part, Cell line, Subject
View SamplesExpression of meningioma 1 (MN1) has been proposed to be a negative prognostic molecular marker in adult AML with normal cytogenetics, however its role in pediatric leukemia is unknown. We found elevated MN1 expression in 53 of 88 pediatric leukemia cases: significant amounts of MN1 were found in immature B-cell ALL and most cases of infant leukemia but no MN1 expression was detected in T-cell acute lymphoblastic leukemia (T-ALL). Interestingly 17 of 19 cases harboring MLL-X fusions showed also elevated MN1 expression. Lentiviral siRNA mediated MN1 knock-down resulted in cell cycle arrest and impaired clonogenic growth of 3 MLL-X-positive human leukemia cell lines overexpressing MN1 (THP-1, RS4;11, MOLM13). In a mouse MLL/ENL-induced leukemia MN1 overexpression resulted from retroviral provirus insertion. Strikingly co-expression of MN1 with MLL/ENL resulted in significantly reduced latency for induction of an AML phenotype in mice suggesting functional cooperation. MN1 overexpression in MLL/ENL-carrying cells resulted in expansion of the L-GMP population and facilitated disease induction in secondary recipients. Gene expression profiling allowed to define a number of potential MN1 hematopoietic targets. Up-regulation of CD34, FLT3, HLF, or DLK1 was validated in bone marrow transiently overexpressing MN1, in MN1-induced mouse leukemias, as well as in some cases of pediatric leukemias overexpressing MN1. Taken together, our work suggests that MN1 overexpression is essential for growth of leukemic cells, and that MN1 can act as a cooperating oncogene with MLL-X fusion genes most probably through modification of a distinct gene expression program that leads to expansion of a leukemia initiating cell population.
Functional characterization of high levels of meningioma 1 as collaborating oncogene in acute leukemia.
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View SamplesThe purpose of this experiment was to assess the genes upregulated when pDCs were stimulated with TLR7 agonist imiquimod and TLR9 agonist CpG C. Overall design: pDCs were isolated from six healthy donors by FACS sorting, and were stimulated with CpG and imiquimod for 18 hours, after which RNA was extracted for next generation sequencing on the Illumina HiSeq platform. Unstimulated samples were included as controls.
A cytotoxic anti-IL-3Rα antibody targets key cells and cytokines implicated in systemic lupus erythematosus.
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