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 SamplesThe transcriptional coregulator Trim24 (formerly known as TIF1a) functions in mice as a liver-specific tumor suppressor. Mice carrying a null mutation in the Trim24 gene all develop hepatocellular carcinoma (HCC).
Loss of Trim24 (Tif1alpha) gene function confers oncogenic activity to retinoic acid receptor alpha.
Age
View SamplesGenome-wide expression analysis of 228 hepatocellular carcinoma and 168 cirrhotic samples as part of a integrated study of gene expression and DNA-methylation de-regulation in patients with hepatocellular carcinoma
DNA methylation-based prognosis and epidrivers in hepatocellular carcinoma.
Sex, Specimen part, Disease, Subject
View SamplesMouse liver tumors (T) and non tumoral adjacent livers (NT) sorted from mice knock out for Axin1 gene specifically in the hepatocytes . 3 mice of the brother hood non deleted for Axin1 were used as controls (WT)
AXIN deficiency in human and mouse hepatocytes induces hepatocellular carcinoma in the absence of β-catenin activation.
Sex, Age, Specimen part
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 SamplesThis SuperSeries is composed of the SubSeries listed below.
microRNA 193a-5p Regulates Levels of Nucleolar- and Spindle-Associated Protein 1 to Suppress Hepatocarcinogenesis.
Specimen part
View SamplesBACKGROUND & AIMS: We performed an integrated analysis to identify microRNAs (miRNAs) and mRNAs with altered expression in liver tumors from 3 mouse models of hepatocellular carcinoma (HCC) and human tumor tissues.
microRNA 193a-5p Regulates Levels of Nucleolar- and Spindle-Associated Protein 1 to Suppress Hepatocarcinogenesis.
Specimen part
View SamplesInhibition of Brd4 with Jq1 in neurons with or without BDNF stimulation Overall design: Examination of the effects of Jq1 treatment on primary mouse cortical neurons
BET protein Brd4 activates transcription in neurons and BET inhibitor Jq1 blocks memory in mice.
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