Early HCC treatment: a future strategy against interferon/miR-484 axis to revert precancerous lesions?

MiR-484 promotes nonalcoholic fatty liver disease progression in mice via downregulation of Sorbs2

OBJECTIVE

MicroRNA 484 (miR-484) plays a pivotal role in the development and progression of different diseases and is typically described as a mitochondrial regulator. Whether miR-484 is involved in lipid metabolism or exerts a role in nonalcoholic fatty liver disease remains unclear.

METHODS

miR-484 levels were examined in the livers of male mice fed a high-fat diet and in hepatocytes treated with free fatty acids. Sorbin and SH3 structural domain-containing protein 2 (Sorbs2) were identified as a novel target of miR-484 by sequencing mRNA in the livers of miR-484 knockout mice. Sorbs2 liver-specific knockdown mice were constructed by tail vein injection of adeno-associated virus vector to miR-484 knockout mice. In addition, genetic manipulation of SORBS2 was performed in human hepatocyte lines, mouse primary hepatocytes, and the liver.

RESULTS

Serum and hepatic miR-484 levels are upregulated in nonalcoholic fatty liver disease mice. miR-484 knockdown ameliorated hepatocyte steatosis, whereas miR-484 overexpression increased hepatocyte lipid load. miR-484 knockdown-mediated alleviation of hepatic steatosis, liver injury, inflammation, and apoptosis was compromised after high-fat diet-induced knockdown of Sorbs2 in mouse liver and free fatty acid-induced primary mouse hepatocytes.

CONCLUSIONS

These results identify Sorbs2-mediated mitochondrial β-oxidation and apoptosis that promote miR-484 knockdown-mediated remission of hepatic steatosis.

Integrated bioinformatics analyses of key genes involved in hepatocellular carcinoma immunosuppression

Hepatocellular carcinoma (HCC) is a typical inflammation-driven cancer. Chronically unresolved inflammation may remodel the immunosuppressive tumor microenvironment, which is rich in innate immune cells. The mechanisms via which HCC progresses through the evasion of the innate immune surveillance remain unclear. The present study thus aimed to identify key genes involved in HCC immunosuppression and to establish an innate immune risk signature, with the ultimate goal of obtaining new insight into effective immunotherapies. HCC and normal liver tissue mRNA expression and clinicopathological data were obtained from the Cancer Genome Atlas database. The immunosuppressive innate immune-related genes (IIRGs) in HCC were screened using integrated bioinformatics analyses. Gene expression was then validated using the Gene Expression Omnibus database and the Human Protein Atlas database, and tissues were obtained from patients with HCC who underwent surgery. In total, 3,676 genes were identified as differentially expressed mRNAs after comparing the HCC tissues with the normal liver tissues in TCGA. Gene Set Enrichment Analyses revealed 21 highly expressed IIRGs in HCC tissues. A survival analysis and Cox regression model were used to construct an innate immune risk signature, including three IIRGs: Collectin-12 (COLEC12), matrix metalloproteinase-12 (MMP12) and mucin-12 (MUC12) genes. Univariate and multivariate Cox analyses revealed that the signature of the three IIRGs was a robust independent risk factor in relation to the overall survival (OS) of patients with HCC. The expression of the three aforementioned IIRGs was confirmed through external validation. Moreover, COLEC12 and MMP12 expression significantly correlated with that of immune checkpoint molecules or immunosuppressive cytokines. The tumor immune dysfunction and exclusion tool predicted that the increased expression of the three IIRGs in patients with HCC was significantly associated with the efficacy of relatively poor immune checkpoint blockade therapy. Conclusively, a novel innate immune-related risk signature for patients with HCC was constructed and validated. This signature may be involved in immunosuppression, and may be used to predict a poor prognosis, functioning as a potential immunotherapeutic target for patients with HCC.

MiR-484 participates in non-alcoholic fatty liver injury by targeting SIRT1 to mediate cell apoptosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become a major health threat that is seriously underestimated. Although the pathogenesis of NAFLD is complex, more and more evidence shows that microRNAs (miRNAs) play an important role in regulating the occurrence and development of NAFLD. Whether miR-484 is involved in the occurrence and development of NAFLD remains to be clarified.

AIM

To explore the mechanism of miR-484 in the damage of liver steatosis.

METHODS

A mouse model of NAFLD was established by feeding mice a high-fat diet, and the expression levels of miR-484 and SIRT1 in liver tissues were measured by RT-qPCR and Western blot. A miR-484 knockout NAFLD mouse model was constructed, the degree of steatosis and apoptosis were detected by oil red O staining, HE staining, and TUNEL staining, and the levels of serum ALT and AST were detected. In addition, a cell model of NAFLD was constructed through free fatty acid exposure. The dual luciferase reporter gene assay was first used to verify the direct targeting relationship between miR-484 and SIRT1, then an SIRT1 overexpression model was constructed by transfection with pc-DNA and pc-DNA SIRT1. Oil red O staining was used to detect lipid accumulation and flow cytometry was used to detect cell apoptosis.

RESULTS

In the mouse model of NAFLD, the expression of miR-484 was significantly up-regulated, while the expression of SIRT1 was decreased. The degree of steatosis was reduced and serum ALT and AST levels were significantly reduced in miR-484 knockout mice. In the cell model of NAFLD, miR-484 can directly target SIRT1. In addition, overexpression of SIRT1 significantly decreased the rate of apoptosis and alleviated lipid accumulation in liver cells

CONCLUSION

MiR-484 regulates cell apoptosis by targeting SIRT1 and aggravates lipid accumulation in liver cells, which suggests that miR-484 may be a therapeutic target for NAFLD.

Circular RNA profiling identifies circADAMTS13 as a miR-484 sponge which suppresses cell proliferation in hepatocellular carcinoma

Circular RNA (circRNA) can participate in various biological processes, including tumorigenesis, through their microRNA response elements. Alterations in circRNA profiles during hepatocellular carcinoma (HCC) progression and their clinical significance remain unclear. Here, we present extensive analysis of circRNA profiles in tumor and matched peritumor tissues collected from 10 HCC patients, conducted to identify circRNA related to HCC progression. A total of 42 dysregulated circRNA (38 down-regulated and 4 up-regulated) were identified in HCC tumor tissues compared with matched peritumor tissues, revealing the heterogeneity of circRNA profiles in HCC. CircADAMTS13, derived from Exon 13-14 of the ADAMTS13 gene, was significantly downregulated in HCC tumor tissues. Furthermore, clinicopathological analysis revealed that up-regulation of circADAMTS13 was negatively associated with tumor size but positively associated with prognosis. In addition, overexpression of circADAMTS13 could markedly inhibit HCC cell proliferation in vitro. Bioinformatic analysis and luciferase reporter assays further revealed that circADAMTS13 directly interacts with microRNA (miR)-484. Rescue experiments showed that miR-484 mimics can reverse the tumor-suppressing roles of circADAMTS13 in HCC. Therefore, our results demonstrated that circADAMTS13 can serve as a tumor suppressor during HCC progression via the functional pathway of sponging miR-484.

Decreased expression of long non-coding RNA LOC728290 in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer-associated mortality worldwide. Despite progress in the diagnosis and treatment of HCC, prognosis remains unfavorable. Long non-coding RNAs (lncRNAs) are emerging as important factors in tumorigenesis and cancer progression; however, the underlying molecular mechanisms and clinical significance of lncRNAs in HCC remain largely unknown. The present study examined the expression pattern and clinical significance of a novel lncRNA, LOC728290, in HCC. Expression of LOC728290 was markedly decreased in HCC tissues compared with adjacent non-tumor liver tissues, as detected using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The area under the receiver operating characteristic curve for LOC728290 was 0.728. The expression of LOC728290 was associated with the level of α-fetoprotein and microvascular invasion. Furthermore, patients with low LOC728290 expression exhibited decreased recurrence-free survival times (P<0.05) compared with those with high LOC728290 expression. The results of the present study indicated that downregulation of LOC728290 in patients with HCC may be a powerful tumor biomarker, with potential clinical applications in prognosis as well as a therapeutic target.

Development of hepatocellular cancer induced by long term low fat-high carbohydrate diet in a NAFLD/NASH mouse model

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease. It can progress to nonalcoholic steatohepatitis (NASH) and, in a percentage of cases, to hepatocarcinogenesis. The strong incidence in western countries of obesity and metabolic syndrome, whose NAFLD is the hepatic expression, is thought to be correlated to consumption of diets characterized by processed food and sweet beverages. Previous studies described high-fat diet-induced liver tumors. Conversely, the involvement of low-fat/high-carbohydrate diet in the progression of liver disease or cancer initiation has not been described yet. Here we show for the first time hepatic cancer formation in low-fat/high-carbohydrate diet fed NAFLD/NASH mouse model. Animals were long term high-fat, low-fat/high-carbohydrate or standard diet fed. We observed progressive liver damage in low-fat/high-carbohydrate and high-fat animals after 12 and, more, 18 months. Tumors were detected in 20% and 50% of high-fat diet fed mice after 12 and 18 months and, interestingly, in 30% of low-fat/high-carbohydrate fed animals after 18 months. No tumors were detected in standard diet fed mice. Global increase of hepatic interleukin-1β, interleukin-6, tumor necrosis factor-α and hepatocyte growth factor was detected in low-fat/high-carbohydrate and high-fat with respect to standard diet fed mice as well as in tumor with respect to non-tumor bearing mice. A panel of 15 microRNAs was analyzed: some of them revealed differential expression in low-fat/high-carbohydrate with respect to high-fat diet fed groups and in tumors. Data here shown provide the first evidence of the involvement of low-fat/high-carbohydrate diet in hepatic damage leading to tumorigenesis.