Significance of promoter methylation of multiple tumor suppressor genes in hepatocellular carcinoma

Background

Methylation of the promoter at CpG islands is a mechanism of silencing tumor suppressor genes and therefore enhances cancer progression. The study aimed to examine promoter methylation frequencies of five tumor suppressor genes in hepatocellular carcinoma and their implication on the first-year outcome of surgical resection of the tumor. Fifty specimens of hepatocellular carcinoma and the adjacent non-tumorous liver tissue were collected from the surgically resected hepatic tumor. The status of promoter methylation of tumor suppressor genes RASSF1A, CHFR, MGMT, GSTP1, and hMLH1 was investigated using methylation-specific polymerase chain reaction.

Results

The frequency of promoter methylation of these tumor suppressors genes (TSG) genes in hepatocellular carcinoma was significantly higher than non-tumorous tissue all, P < 0.05, with a methylation rate of 80% in RASSF1A, 70% in CHFR, 46% in GSTP1, 56% in MGMT, and 10% in hMLH1. Methylation of RASSF1A, CHFR, and MGMT promoter genes was significantly associated with decreased first-year postoperative survival and increased recurrence of hepatocellular carcinoma, P < 0.05.

Conclusion

Methylated RASSF1A, CHRF, and MGMT promoters indicated poor prognosis among patients with hepatocellular carcinoma and may serve as potential prognostic indicators in patients with hepatocellular carcinoma.

Epigenetic priming in chronic liver disease impacts the transcriptional and genetic landscapes of hepatocellular carcinoma

Hepatocellular carcinomas (HCCs) usually arise from chronic liver disease (CLD). Precancerous cells in chronically inflamed environments may be 'epigenetically primed', sensitising them to oncogenic transformation. We investigated whether epigenetic priming in CLD may affect HCC outcomes by influencing the genomic and transcriptomic landscapes of HCC. Analysis of DNA methylation arrays from 10 paired CLD-HCC identified 339 shared dysregulated CpG sites and 18 shared differentially methylated regions compared with healthy livers. These regions were associated with dysregulated expression of genes with relevance in HCC, including ubiquitin D (UBD), cytochrome P450 family 2 subfamily C member 19 (CYP2C19) and O-6-methylguanine-DNA methyltransferase (MGMT). Methylation changes were recapitulated in an independent cohort of nine paired CLD-HCC. High CLD methylation score, defined using the 124 dysregulated CpGs in CLD and HCC in both cohorts, was associated with poor survival, increased somatic genetic alterations and TP53 mutations in two independent HCC cohorts. Oncogenic transcriptional and methylation dysregulation is evident in CLD and compounded in HCC. Epigenetic priming in CLD sculpts the transcriptional landscape of HCC and creates an environment favouring the acquisition of genetic alterations, suggesting that the extent of epigenetic priming in CLD could influence disease outcome.

Association between SOCS3 hypermethylation and HBV-related hepatocellular carcinoma and effect of sex and age: A meta-analysis

BACKGROUND

Suppressor 3 of cytokine signaling (SOCS3) hypermethylation has been reported to participate in hepatocellular carcinoma (HCC) development and progression, but conflicting results were published. This study aimed to analyze the clinical effects of SOCS3 hypermethylation in HCC and the effects of sex and age on SOCS3 hypermethylation in HCC.

METHODS

Databases were searched for relevant case-control and cohort studies on SOCS3 hypermethylation in HBV-related HCC. In vitro and in vivo studies and studies of patients with serious comorbidities were excluded. Review Manager 5.2 was used to estimate the effects of the results among the selected studies. Forest plots, sensitivity analysis, and bias analysis for the included studies were also conducted.

RESULTS

Finally, 8 relevant studies met the inclusion criteria. A significant difference in SOCS3 hypermethylation in HCC was found between tumor and nontumor groups (the odds ratio [OR] = 2.01, 95% confidence interval [CI]: 1.48-2.73, P < .00001; P for heterogeneity = .39, I2 = 5%). The meta-analysis suggested no significant difference in the effect of sex (OR = 1.00, 95% CI: 0.76-1.31, P = .76; P for heterogeneity = .44, I2 = 0%) and age on SOCS3 hypermethylation in HCC (OR = 1.11, 100% CI: 0.78-1.29, P = .03; P for heterogeneity = .14, I2 = 36%). Limited publication bias was observed in this study.

CONCLUSION

SOCS3 hypermethylation is associated with HBV-related HCC. Sex and age do not affect the association between SOCS3 hypermethylation and HCC. SOCS3 might be a treatment target for HCC.

Sex and Race-Related DNA Methylation Changes in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer and fourth leading cause of cancer-related death worldwide. The number of HCC cases continues to rise despite advances in screening and therapeutic inventions. More importantly, HCC poses two major health disparity issues. First, HCC occurs more commonly in men than women. Second, with the global increase in non-alcoholic fatty liver diseases (NAFLD), it has also become evident that HCC is more prevalent in some races and/or ethnic groups compared to others, depending on its predisposing etiology. Most studies on HCC in the past have been focused on genetic factors as the driving force for HCC development, and the results revealed that genetic mutations associated with HCC are often heterogeneous and involve multiple pathogenic pathways. An emerging new research field is epigenetics, in which gene expression is modified without altering DNA sequences. In this article, we focus on reviewing current knowledge on HCC-related DNA methylation changes that show disparities among different sexes or different racial/ethnic groups, in an effort to establish a point of departure for resolving the broader issue of health disparities in gastrointestinal malignancies using cutting-edge epigenetic approaches.

miR-221-3p promotes hepatocellular carcinogenesis by downregulating O6-methylguanine-DNA methyltransferase

This study aimed to investigate the influence of miR-221-3p and O⁶-methylguanine-DNA methyltransferase (MGMT) interaction in human hepatocellular carcinoma (HCC), thereby revealing a novel molecular mechanism of hepatic carcinogenesis involving miR-221-3p and MGMT.

Fluorescence qPCR and immunoblot assays were performed to determine the expression of RNA and protein in HCC tissues and cell lines. We also employed the firefly and Renilla luciferase assay to verify the target relationship between miR-221-3p and MGMT mRNA. Assessments including the MTT assay, wound-healing assay, transwell assay, colony foci formation experiment, and flow cytometric experiment were carried out to determine the viability, migration, invasion, proliferation, cell cycle progression, and apoptosis of SMMC-7721 and BEL-7404 cell lines with the modulated expression of miR-221-3p and MGMT. Compared to healthy tissues and cell line HL7702, miR-221-3p was significantly upregulated but MGMT was significantly downregulated in carcinomas and cancerous cell lines. Forced miR-221-3p overexpression was found to enhance the proliferation, migration, invasion, and clonogenicity of cell lines, but it suppressed cell apoptosis. Findings also revealed that forced miR-221-3p overexpression had little effect on cell cycle progression. After MGMT was confirmed to be atarget gene of miR-221-3p, it was found that the forced upregulation of miR-221-3p downregulated MGMT mRNA and protein levels significantly. MiR-221-3p was identified as an HCC promoting factor, and it specifically inhibited the expression of the MGMT. Besides, the upregulation of miR-221-3p had apositive influence on HCC pathogenesis by inhibiting MGMT expression.

Studying the frequency of aberrant DNA methylation of APC, P14, and E-cadherin genes in HCV-related hepatocarcinogenesis

BACKGROUND

Data about the molecular pathogenesis of hepatitis C-related hepatocellular carcinoma (HCC) are still challenging.

OBJECTIVES

Therefore, we tried to investigate the epigenetic study of three nominated genes (APC, P14, and E-cadherin) in the pathogenesis of HCV-related HCC in Egyptian.

METHODS

Between March 2016 and March 2017, the DNA methylation, and quantification using (epigenetic ELISA kit) for E-cadherin, APC, and P14 genes were studied in three groups of patients: HCV related liver cirrhosis without HCC group (LC-group; n= 20), HCC on top of HCV-related cirrhosis (HCC-group; n= 20), and a third apparently healthy control group (control-group; n= 10).

RESULTS

E-cad methylation showed non-significant differences between groups. P14 methylation was occurred only in HCC-group (45%). APC methylation was the highest in HCC group (70%). Methylation level was high in HCC group in comparison to both LC and control groups (P< 0.001). DNA methylation at a cutoff point > 2.9 ng/ml predicts HCC in LC-group with 90% sensitivity and 80% specificity and at level > 2.3 ng/ml had 95% sensitivity and 90% specificity in control-group. The pooled sensitivity, specificity, positive and negative predictive values and accuracy were 90%, 60%, 69.2, 85.7 and 75% respectively.

CONCLUSION

Aberrant DNA methylation of multiple genes is associated with disease progression in HCV related cirrhosis. Moreover, early detection of promotor methylation of these may sever as good biomarker for early detection and therapeutic targets in high risk patients.

p16 Methylation was associated with the development, age, hepatic viruses infection of hepatocellular carcinoma, and p16 expression had a poor survival: A systematic meta-analysis (PRISMA)

BACKGROUND

Loss of tumor suppressor gene p16 expression via promoter methylation has been reported in hepatocellular carcinoma (HCC). This meta-analysis was conducted to evaluate the correlation between p16 methylation and HCC. Additionally, we also analyzed the potential prognostic role of p16 methylation, expression or alteration-associated HCC.

METHODS

Online databases based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline were performed to analyze the role of p16 gene in HCC. The combined odds ratios (ORs) or hazard ratios (HRs) and their 95% confidence intervals (95% CIs) were summarized.

RESULTS

Final 3105 HCCs and 808 non-tumor controls (chronic hepatitis and liver cirrhosis) were performed in this meta-analysis. p16 promoter methylation in HCC was significantly higher than in chronic hepatitis and chronic hepatitis in tissue and blood samples. In addition, p16 promoter methylation was notably higher in patients >50 years' old than in patients aged <50 years, and it was higher in hepatitis B virus (HBV) or hepatitis C virus (HCV)-positive HCC than in hepatic viruses-negative HCC. However, p16 promoter methylation was not correlated with sex, cirrhosis, tumor differentiation, clinical stage. No association was found between p16 methylation or alteration and the prognosis of patients with HCC in overall survival (OS) and disease-free survival (DFS). Although p16 expression was significantly correlated with a poor prognosis in OS and DFS (P < .05) CONCLUSIONS:: Our results indicate that p16 methylation was linked to the development, age, HBV, and HCV infection of HCC. p16 methylation or alteration was not associated with the prognosis, but p16 expression was linked to a poor survival.

The Correlation Relationship between P14ARF Gene DNA Methylation and Primary Liver Cancer

Background

Primary liver cancer is a common malignant tumor that causes serious damage to human health. DNA methylation is common in epigenetics. DNA methylation plays an important role in the process of primary liver cancer occurrence and development. The P14^ARF gene is an important tumor suppressor gene. It was found that P14^ARF methylation is associated with the degree of malignancy in multiple tumors. Therefore, this study aimed to investigate the relationship between P14^ARF methylation level and primary liver cancer malignant degree.

Material/Methods

Carcinoma tissues and adjacent tissues were collected from 87 primary liver cancer patients. Pyrosequencing was applied to obtain P14^ARF methylation. Real-time PCR was used to detect P14^ARF mRNA level.

Results

P14^ARF methylation level in cancerous tissue was significantly higher than in the adjacent tissue (t=76.54, P<0.001). P14^ARF methylation showed no significant difference in patients with different age, sex, smoking status, or drinking status. It did not present an obvious difference in tumors with different size. Its methylation level increased following the improvement of TNM stage (P<0.05). Compared with the adjacent tissue, P14^ARF mRNA in carcinoma tissue decreased by 31% (t=28.91, P<0.001). P14^ARF methylation showed a significant negative correlation with mRNA expression in cancerous tissue (r=−0.43, P<0.01).

Conclusions

P14^ARF mRNA level is regulated by DNA methylation in primary liver cancer. P14^ARF gene DNA methylation may be associated with the occurrence of primary liver cancer occurrence and TNM staging.