The transcriptome of early GGT/KRT19-positive hepatocellular carcinoma reveals a downregulated gene expression profile associated with fatty acid metabolism

Intriguing hepatoprotective effects of sucrose on hepatocellular carcinoma pathogenesis

Chronic liver disease is closely linked to dietary intake factors, such as high consumption of simple carbohydrates including sucrose. In this study, the influence of sucrose on the development of hepatocellular carcinoma (HCC), the most common primary liver malignancy, was explored. Using the hepatocarcinogen diethylnitrosamine (DEN) to induce HCC in the rat, we co-administered sucrose with DEN. The co-administration significantly modified body, liver and pancreas weight, as well as, serum fatty acids and triglycerides. DEN caused liver structural alteration, fibrosis, and tumor formation; surprisingly, co-administration with sucrose restored hepatic lipids, improved liver architecture, and reduced fibrosis and tumor development. Sucrose intake negatively regulated tumor markers and cell proliferation, and reduced the expression of genes associated with lipid metabolism and oxidative stress response. These findings highlight a hepatoprotective effect of sucrose during DEN-induced hepatocarcinogenesis, underlining an intriguing role of high sucrose consumption during HCC development and providing new insights as well as possible pathways of cellular protection under sucrose intake on hepatocarcinogenesis.

Epigenetic heterogeneity hotspots in human liver disease progression

BACKGROUND AND AIMS

Disruption of the epigenome is a hallmark of human disease, including liver cirrhosis and HCC. While genetic heterogeneity is an established effector of pathologic phenotypes, epigenetic heterogeneity is less well understood. Environmental exposures alter the liver-specific DNA methylation landscape and influence the onset of liver cancer. Given that currently available treatments are unable to target frequently mutated genes in HCC, there is an unmet need for novel therapeutics to prevent or reverse liver damage leading to hepatic tumorigenesis, which the epigenome may provide.

APPROACH AND RESULTS

We performed genome-wide profiling of DNA methylation, copy number, and gene expression from multiple liver regions from 31 patients with liver disease to examine their crosstalk and define the individual and combinatorial contributions of these processes to liver disease progression. We identified epigenetic heterogeneity hotspots that are conserved across patients. Elevated epigenetic heterogeneity is associated with increased gene expression heterogeneity. Cirrhotic regions comprise 2 distinct cohorts-one exclusively epigenetic, and the other where epigenetic and copy number variations collaborate. Epigenetic heterogeneity hotspots are enriched for genes central to liver function (eg, HNF1A ) and known tumor suppressors (eg, RASSF1A ). These hotspots encompass genes including ACSL1 , ACSL5 , MAT1A , and ELFN1 , which have phenotypic effects in functional screens, supporting their relevance to hepatocarcinogenesis. Moreover, epigenetic heterogeneity hotspots are linked to clinical measures of outcome.

CONCLUSIONS

Substantial epigenetic heterogeneity arises early in liver disease development, targeting key pathways in the progression and initiation of both cirrhosis and HCC. Integration of epigenetic and transcriptional heterogeneity unveils putative epigenetic regulators of hepatocarcinogenesis.

Identification of Candidate Genes and Regulatory Competitive Endogenous RNA (ceRNA) Networks Underlying Intramuscular Fat Content in Yorkshire Pigs with Extreme Fat Deposition Phenotypes

Intramuscular fat (IMF) content is vital for pork quality, serving an important role in economic performance in pig industry. Non-coding RNAs, with mRNAs, are involved in IMF deposition; however, their functions and regulatory mechanisms in porcine IMF remain elusive. This study assessed the whole transcriptome expression profiles of the Longissimus dorsi muscle of pigs with high (H) and low (L) IMF content to identify genes implicated in porcine IMF adipogenesis and their regulatory functions. Hundreds of differentially expressed RNAs were found to be involved in fatty acid metabolic processes, lipid metabolism, and fat cell differentiation. Furthermore, combing co-differential expression analyses, we constructed competing endogenous RNAs (ceRNA) regulatory networks, showing crosstalk among 30 lncRNAs and 61 mRNAs through 20 miRNAs, five circRNAs and 11 mRNAs through four miRNAs, and potential IMF deposition-related ceRNA subnetworks. Functional lncRNAs and circRNAs (such as MSTRG.12440.1, ENSSSCT00000066779, novel_circ_011355, novel_circ_011355) were found to act as ceRNAs of important lipid metabolism-related mRNAs (LEP, IP6K1, FFAR4, CEBPA, etc.) by sponging functional miRNAs (such as ssc-miR-196a, ssc-miR-200b, ssc-miR10391, miR486-y). These findings provide potential regulators and molecular regulatory networks that can be utilized for research on IMF traits in pigs, which would aid in marker-assisted selection to improve pork quality.

Downregulation of Indolethylamine N-methyltransferase is an early event in the rat hepatocarcinogenesis and is associated with poor prognosis in hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is one of the deadliest cancers worldwide, often preceded by cirrhosis and usually diagnosed at advanced stages; therefore, identifying molecular changes at early stages is an attractive strategy for detection and timely treatment. Here, we investigated the progressive transcriptomic changes during experimental hepatocarcinogenesis to identify novel early tumor markers in an HCC model induced by chronic administration of sublethal doses of diethylnitrosamine. An analysis of differentially expressed genes showed that four processes associated with oxidation-reduction and detoxification were significantly overrepresented during hepatocarcinogenesis progression, of which the Nuclear Factor, Erythroid 2 Like 2 (NRF2) pathway showed several dysregulated genes. Interestingly, we also identified 91 genes dysregulated at early HCC stages, but the expression of the indolethylamine N-methyltransferase gene (Inmt), as well as the level of its encoding protein, were strongly downregulated. INMT was increased in perivenular hepatocytes of normal livers but decreased in livers of experimental HCC. Furthermore, a gene expression and survival analysis performed using data from the liver hepatocellular carcinoma project of The Cancer Genome Atlas Program revealed that INMT is also significantly downregulated in human HCC and is associated with poor overall survival. In conclusion, by performing a transcriptome analysis of the HCC progression, we identified that INMT is early downregulated in the rat hepatocarcinogenesis and is associated with poor prognosis in human HCC, suggesting that INMT downregulation may be a promising prognostic marker for HCC in high-risk populations.