Hepatocellular carcinoma: Therapeutic advances in signaling, epigenetic and immune targets

Liver-specific deletion of de novo DNA methyltransferases protects against glucose intolerance in high-fat diet-fed male mice

Alterations to gene transcription and DNA methylation are a feature of many liver diseases including fatty liver disease and liver cancer. However, it is unclear whether the DNA methylation changes are a cause or a consequence of the transcriptional changes. It is even possible that the methylation changes are not required for the transcriptional changes. If DNA methylation is just a minor player in, or a consequence of liver transcriptional change, then future studies in this area should focus on other systems such as histone tail modifications. To interrogate the importance of de novo DNA methylation, we generated mice that are homozygous mutants for both Dnmt3a and Dnmt3b in post-natal liver. These mice are viable and fertile with normal sized livers. Males, but not females, showed increased adipose depots, yet paradoxically, improved glucose tolerance on both control diet and high-fat diets (HFD). Comparison of the transcriptome and methylome with RNA sequencing and whole-genome bisulfite sequencing in adult hepatocytes revealed that widespread loss of methylation in CpG-rich regions in the mutant did not induce loss of homeostatic transcriptional regulation. Similarly, extensive transcriptional changes induced by HFD did not require de novo DNA methylation. The improved metabolic phenotype of the Dnmt3a/3b mutant mice may be mediated through the dysregulation of a subset of glucose and fat metabolism genes which increase both glucose uptake and lipid export by the liver. However, further work is needed to confirm this.

Sorafenib and Piperine co-loaded PLGA nanoparticles: Development, characterization, and anti-cancer activity against hepatocellular carcinoma cell line

Hepatocellular carcinoma (HCC) exhibits high mortality rates in the advanced stage (>90 %). Sorafenib (SORA) is a targeted therapy approved for the treatment of advanced HCC; however, the reported response rate to such a therapeutic is suboptimal (<3%). Piperine (PIP) is an alkaloid demonstrated to exert a direct tumoricidal activity in HCC and improve the pharmacokinetic profiles of anticancer drugs including SORA. In this study, we developed a strategy to improve efficacy outcomes in HCC using PIP as an add-on treatment to support the first-line therapy SORA using biodegradable Poly (D, L-Lactide-co-glycolide, PLGA) nanoparticles (NPs). SORA and PIP (both exhibit low aqueous solubility) were co-loaded into PLGA NPs (PNPs) and stabilized with various concentrations of polyvinyl alcohol (PVA). The SORA and PIP-loaded PNPs (SP-PNPs) were characterized using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Powder Diffraction (XRD), Dynamic Light Scattering (DLS), and Scanning Electron Microscopy (SEM), Release of these drugs from SP-PNPs was investigated in vitro at both physiological and acidic pH, and kinetic models were employed to assess the mechanism of drug release. The in vitro efficacy of SP-PNPs against HCC cells (HepG2) was also evaluated. FTIR and XRD analyses revealed that the drugs encapsulated in PNPs were in an amorphous state, with no observed chemical interactions among the drugs or excipients. Assessment of drug release in vitro at pH 5 and 7.4 showed that SORA and PIP loaded in PNPs with 0.5 % PVA were released in a sustained manner, unlike pure drugs, which exhibited relatively fast release. SP-PNPs with 0.5 % PVA were spherical, had an average size of 224 nm, and had a high encapsulation efficiency (SORA ∼ 82 %, PIP ∼ 79 %), as well as superior cytotoxicity compared to SORA monotherapy in vitro. These results suggest that combining PIP with SORA using PNPs may be an effective strategy for the treatment of HCC and may set the stage for a comprehensive in vivo study to evaluate the efficacy and safety of this novel formulation using a murine HCC model.

Screening of miRNAs as prognostic biomarkers and their associated hub targets across Hepatocellular carcinoma using survival-based bioinformatics approach

BACKGROUND

The hepatocellular carcinoma (HCC) incident rate is gradually increasing yearly despite all the research and efforts taken by scientific communities and governing bodies. Approximately 90% of all liver cancer cases belong to HCC. Usually, HCC patients approach the treatment in the late stages of this malignancy which becomes the primary cause of high mortality rate. The knowledge about molecular pathogenesis of HCC is limited and needs more attention from researchers to identify the driver genes and miRNAs, which causes to translate this information into clinical practice. Therefore, the key regulators identification of miRNA-mRNA regulatory network is essential to identify HCC-associated genes.

METHODOLOGY

We extracted microRNA (miRNA) and messenger RNA (mRNA) expression datasets of normal and tumor HCC patient samples from UCSC Xena followed by identifying differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs). Univariate and multivariate cox-proportional hazard models were utilized to identify DEMs having significant association with overall survival (OS). Kaplan-Meier (KM) plotter was used to validate the presence of prognostic DEMs. A risk-score model was used to evaluate the effectiveness of KM-plotter validated DEMs combination on risk of samples. Target DEGs of prognostic miRNAs were identified via sources such as miRTargetLink and miRWalk followed by their validation in an external microarray cohort and enrichment analysis.

RESULTS

562 DEGs and 388 DEMs were identified followed by seven prognostic miRNAs (i.e., miR-19a, miR-19b, miR-30d-5p, miR-424-5p, miR-3677-5p, miR-3913-5p, miR-7705) post univariate, multivariate, risk-score model evaluation and KM-plotter analyses. ANLN, MRO, CPEB3 were their targets and were also validated in GSE84005 dataset.

CONCLUSIONS

The findings of this study decipher that most significant miRNAs and their identified target genes have association with apoptosis, inflammation, cell cycle regulation and cancer-related pathways, which appear to contribute to HCC pathogenesis and therefore, the discovery of new targets.

Combination of epidrugs with immune checkpoint inhibitors in cancer immunotherapy: From theory to therapy

Immunotherapy based on immune checkpoint inhibitors (ICIs) has revolutionized treatment strategies in multiple types of cancer. However, the resistance and relapse as associated with the extreme complexity of cancer-immunity interactions remain a major challenge to be resolved. Owing to the epigenome plasticity of cancer and immune cells, a growing body of evidence has been presented indicating that epigenetic treatments have the potential to overcome current limitations of immunotherapy, thus providing a rationalefor the combination of ICIs with epigenetic agents (epidrugs). In this review, we first make an overview about the epigenetic regulations in tumor biology and immunodevelopment. Subsequently, a diverse array of inhibitory agents under investigations targeted epigenetic modulators (Azacitidine, Decitabine, Vorinostat, Romidepsin, Belinostat, Panobinostat, Tazemetostat, Enasidenib and Ivosidenib, etc.) and immune checkpoints (Atezolizmab, Avelumab, Cemiplimab, Durvalumb, Ipilimumab, Nivolumab and Pembrolizmab, etc.) to increase anticancer responses were described and the potential mechanisms were further discussed. Finally, we summarize the findings of clinical trials and provide a perspective for future clinical studies directed at investigating the combination of epidrugs with ICIs as a treatment for cancer.

MicroRNA-483-5p Inhibits Hepatocellular Carcinoma Cell Proliferation, Cell Steatosis, and Fibrosis by Targeting PPARα and TIMP2

MicroRNAs (miRNAs) are small non-coding RNA molecules that bind with the 3′ untranslated regions (UTRs) of genes to regulate expression. Downregulation of miR-483-5p (miR-483) is associated with the progression of hepatocellular carcinoma (HCC). However, the significant roles of miR-483 in nonalcoholic fatty liver disease (NAFLD), alcoholic fatty liver diseases (AFLD), and HCC remain elusive. In the current study, we investigated the biological significance of miR-483 in NAFLD, AFLD, and HCC in vitro and in vivo. The downregulation of miR-483 expression in HCC patients’ tumor samples was associated with Notch 3 upregulation. Overexpression of miR-483 in a human bipotent progenitor liver cell line HepaRG and HCC cells dysregulated Notch signaling, inhibited cell proliferation/migration, induced apoptosis, and increased sensitivity towards antineoplastic agents sorafenib/regorafenib. Interestingly, the inactivation of miR-483 upregulated cell steatosis and fibrosis signaling by modulation of lipogenic and fibrosis gene expression. Mechanistically, miR-483 targets PPARα and TIMP2 gene expression, which leads to the suppression of cell steatosis and fibrosis. The downregulation of miR-483 was observed in mice liver fed with a high-fat diet (HFD) or a standard Lieber-Decarli liquid diet containing 5% alcohol, leading to increased hepatic steatosis/fibrosis. Our data suggest that miR-483 inhibits cell steatosis and fibrogenic signaling and functions as a tumor suppressor in HCC. Therefore, miR-483 may be a novel therapeutic target for NAFLD/AFLD/HCC management in patients with fatty liver diseases and HCC.

Custom gene expression panel for evaluation of potential molecular markers in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide. It is a highly heterogeneous disease with poor prognosis and limited treatment options, which highlights the need for reliable biomarkers. This study aims to explore molecular markers that allow stratification of HCC and may lead to better prognosis and treatment prediction.

MATERIALS AND METHODS

We studied 20 candidate genes (HCC hub genes, potential drug target genes, predominant somatic mutant genes) retrieved from literature and public databases with potential to be used as the molecular markers. We analysed expression of the genes by RT-qPCR in 30 HCC tumour and adjacent non-tumour paired samples from Vietnamese patients. Fold changes in expression were then determined using the 2^-∆∆CT method, and unsupervised hierarchical clustering was generated using Cluster v3.0 software.

RESULTS

Clustering of expression data revealed two subtypes of tumours (proliferative and normal-like) and four clusters for genes. The expression profiles of the genes TOP2A, CDK1, BIRC5, GPC3, IGF2, and AFP were strongly correlated. Proliferative tumours were characterized by high expression of the c-MET, ARID1A, CTNNB1, RAF1, LGR5, and GLUL1 genes. TOP2A, CDK1, and BIRC5 HCC hub genes were highly expressed (> twofold) in 90% (27/30), 83% (25/30), and 83% (24/30) in the tissue samples, respectively. Among the drug target genes, high expression was observed in the GPC3, IGF2 and c-MET genes in 77% (23/30), 63% (19/30), and 37% (11/30), respectively. The somatic mutant Wnt/ß-catenin genes (CTNNB1, GLUL and LGR5) and TERT were highly expressed in 40% and 33% of HCCs, respectively. Among the HCC marker genes, a higher percentage of tumours showed GPC3 expression compared to AFP expression [73% (23/30) vs. 43% (13/30)].

CONCLUSION

The custom panel and molecular markers from this study may be useful for diagnosis, prognosis, biomarker-guided clinical trial design, and prediction of treatment outcomes.

Immunotherapy for hepatocellular carcinoma: A promising therapeutic option for advanced disease

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, and its incidence continues to increase. Despite improvements in both medical and surgical therapies, HCC remains associated with poor outcomes due to its high rates of recurrence and mortality. Approximately 50% of patients require systemic therapies that traditionally consist of tyrosine kinase inhibitors. Recently, however, immune checkpoint inhibitors have revolutionized HCC management, providing new therapeutic options. Despite these major advances, the different factors involved in poor clinical responses and molecular pathways leading to resistance following use of these therapies remain unclear. Alternative strategies, such as adoptive T cell transfer, vaccination, and virotherapy, are currently under evaluation. Combinations of immunotherapies with other systemic or local treatments are also being investigated and may be the most promising opportunities for HCC treatment. The aim of this review is to provide updated information on currently available immunotherapies for HCC as well as future perspectives.

Prognostic significance and immune characteristics of CMTM4 in hepatocellular carcinoma

Background

Previous study has shown that chemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family member 4 (CMTM4) can bind and maintain programmed cell death ligand 1 (PD-L1) expression to promote tumor progression by alleviating the suppression of tumor-specific T cell activity, suggesting its potential role in tumor immunotherapy. However, the role of CMTM4 in tumor immunity has not been well clarified, especially in hepatocellular carcinoma (HCC).

Methods

The protein expression of CMTM4/PD-L1/CD4/CD8 was detected by immunohistochemistry (IHC) detection in 90 cases of HCC tissues. The mRNA expression profiles and related prognosis data were obtained from The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC). Two immune therapy cohorts were from Imvigor210 and GSE176307.

Results

Though the single protein expression of CMTM4, PD-L1, CD4 or CD8 in HCC tissues by IHC detection didn’t show a significant relationship with the prognosis of HCC patients, we found that high co-expression of CMTM4/PD-L1/CD4 showed a good prognosis of HCC patients. Further Timer 2.0 analysis identified that HCC patients with high expression of CMTM4/PD-L1 and high infiltration of CD4⁺ T cells had a better overall survival than those with low infiltration of CD4⁺ T cells. Moreover, a series of bioinformatics analyses revealed that CMTM4-related genes posed important effects on prognosis and immunity in HCC patients, and CMTM4 had a positive correlation with infiltration of CD4⁺ and CD8⁺ T cells in HCC. At last, we used two immunotherapy cohorts to verify that the combination of CMTM4 with PD-L1 could improve the prognosis of tumor patients underwent immunotherapy.

Conclusions

CMTM4 and PD-L1 co-expression with T cell infiltration shows prognostic significance in HCC, suggesting combined effect from multiple proteins should be considered in HCC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09999-y.

SETD3 Methyltransferase Regulates PLK1 Expression to Promote In Situ Hepatic Carcinogenesis

Background

The development of a new strategy to overcome chemoresistance to hepatocellular carcinoma (HCC) treatment is a long-standing issue. We have previously found that upregulated SETD3 levels are closely correlated with HCC. This study aims to explore the mechanism underlying how upregulation of SETD3 promotes liver carcinogenesis.

Methods

RNA-Sequencing analysis was used to explore the correlation of SETD3 with regulatory targets. In vitro assays including cell proliferation and migration were performed to study the oncogenic roles of SETD3 and PLK1. Western blotting, immunohistochemical staining, and blood biochemical assays were performed to examine protein expression or pathological index in tumor tissues and mice liver tissues. Luciferase reporter system and chromatin immunoprecipitation assays were used to explore the mechanism.

Results

We revealed that SETD3 regulates gene expression in subgroups, including cell division, cell proliferation, and cell cycle, in hepatocellular tumor cells. We found that SETD3 upregulation is associated with elevated PLK1 level in both hepatic tumor cells and clinical liver tissues. We further showed that overexpression of SETD3 promoted tumor cell proliferation and migration, whereas inhibition of PLK1 activity attenuated these phenotypes caused by SETD3. By taking advantage of the Sleep Beauty transposase system, we confirmed that upregulated mouse Setd3 promoted hepatic carcinogenesis in situ, but knockdown of mouse Plk1 mitigated Setd3-promoted tumorigenesis in mice. Mechanistically, we showed that SETD3 could be recruited to the promoter of PLK1 gene to facilitate PLK1 transcription.

Conclusions

Our data demonstrate that elevated SETD3 may promote HCC by enhancing PLK1 expression, which suggests that SETD3 may act as a potential drug target combined with PLK1 inhibition to treat HCC.

mRNA expression and epigenetic-based role of chromodomain helicase DNA-binding 5 in hepatocellular carcinoma

Objective

Chromodomain helicase DNA-binding 5 (CHD5) acts as a tumor suppressor gene in some cancers. CHD5 expression levels may affect an individual’s susceptibility to hepatocellular carcinoma (HCC). This study aimed to evaluate the methylation pattern of the CHD5 promoter region and the gene’s corresponding mRNA expression in HCC patients compared with healthy individuals.

Methods

In this case–control study, CHD5 mRNA gene expression levels and DNA methylation patterns were analyzed in 81 HCC patients and 90 healthy individuals by quantitative reverse transcription polymerase chain reaction and methylation-specific polymerase chain reaction, respectively.

Results

The CHD5 gene was hypermethylated in 61.8% of the HCC patients and 54.4% of the controls, and this difference was statistically significant. The CHD5 mRNA expression levels were significantly lower in the HCC patient group.

Conclusions

Hypermethylation of the CHD5 promoter region may significantly lower the expression of this gene, affecting the incidence and severity of HCC. The methylation status of CHD5 can also be further studied as a prognostic factor in HCC.

Immune cell infiltration and immunotherapy in hepatocellular carcinoma

Hepatocellular carcinoma is a highly malignant tumor and patients yield limited benefits from the existing treatments. The application of immune checkpoint inhibitors is promising but the results described in the literature are not favorable. It is therefore urgent to systematically analyze the immune microenvironment of HCC and screen the population best suited for the application of immune checkpoint inhibitors to provide a basis for clinical treatment. In this study, we collected The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC)-related data sets to evaluate the immune microenvironment and immune cell infiltration (ICI) in HCC. Three independent ICI subtypes showing significant differences in survival were identified. Further, TCGA-LIHC immunophenoscore (IPS) was used to identify the differentially expressed genes between high- and low-IPS in HCC, so as to identify the immune gene subtypes in HCC tumors. The ICI score model for HCC was constructed, whereby we divided HCC samples into high- and low-score groups based on the median ICI score. The differences between these groups in genomic mutation load and immunotherapy benefit in HCC were examined in detail to provide theoretical support for accurate immunotherapy strategy in HCC. Finally, four genes were screened, which could accurately predict the subtype based on the tumor immune infiltration score. The findings may provide a basis and simplify the process for screening clinical drugs suitable for relevant subgroups.

Diagnostic and prognostic values of pyroptosis-related genes for the hepatocellular carcinoma

Background

Due to the high heterogeneity, the early diagnosis and prognostic prediction of hepatic cellular cancer (HCC) is challenging. In this study, we explored the diagnostic and prognostic value of pyroptosis-related genes (PRGs) in HCC. We downloaded the mRNA expression profiles of HCC and the corresponding clinical data from the TCGA and ICGC databases. Fifty-one PRGs were extracted from Genecards, MsigDB, and relevant literature. The area under the receiver operating characteristic (AUC) was used to explore the diagnostic value of the PRGs.

Results

The results revealed that BAK1, BAX, CHMP2A, CHMP4C, CHMP6, GSDMC, and GSDMD had higher diagnostic values for HCC (AUCs > 0.8, P < 0.05). Then, univariate and multivariate analyses of 51 PRGs were performed for HCC samples, and 4 PRGs (TP53, GPX4, GSDMC, BAK1) associated with HCC prognosis were obtained and used to construct a pyroptosis-related risk model. HCC samples were divided into high-risk and low-risk groups based on the risk score’s cut-off. Kaplan–Meier curve and Log-rank test were used to compare the overall survival (OS) of two risk groups. The OS was lower in the high-risk group than in the low-risk group. In addition, the time-dependent receiver operating characteristics revealed that the risk model could be used to predict the prognosis of HCC more accurately. The risk score also resulted as an independent risk factor for HCC prognosis (TCGA: HR = 2.45, 95% CI 1.53–3.92; ICGC: HR = 2.19, 95% CI 1.39–3.46). Moreover, the AUC of the risk score for diagnosing HCC was relatively higher (TCGA: AUC = 0.840, P < 0.05; ICGC: AUC = 0.795, P < 0.05).

Conclusions

In a word, BAK1, BAX, CHMP2A, CHMP4C, CHMP6, GSDMC, GSDMD, and the pyroptosis-related risk model could be used to diagnose the HCC, and the risk score also resulted as an independent risk factor for the HCC prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-022-04726-7.

Ferroptosis in Hepatocellular Carcinoma: Mechanisms, Drug Targets and Approaches to Clinical Translation

Simple Summary

In recent decades, scientific discoveries brought up several new treatments and improvements for patients suffering from hepatocellular carcinoma (HCC). However, increasing resistance to current therapies, such as sorafenib, worsen the outcome of HCC patients, leading to a search for alternative therapeutic strategies. The term ferroptosis describes a novel form of regulated cell death, which is different from apoptosis and necroptosis in a mechanistical and morphological manner. The main mechanism, which leads to cell death, is lipid peroxidation, caused by iron overload and the accumulation of polyunsaturated fatty acids. Recent studies demonstrate that ferroptosis can hamper the carcinogenesis in several tumor entities and in HCC. Therefore, a better understanding and a deeper insight in the processes of ferroptosis in HCC and the possible application of it in the clinical practice are of extreme importance.

Abstract

Ferroptosis, an iron and reactive oxygen species (ROS)-dependent non-apoptotic type of regulated cell death, is characterized by a massive iron overload and peroxidation of polyunsaturated fatty acids (PUFAs), which finally results in cell death. Recent studies suggest that ferroptosis can influence carcinogenesis negatively and therefore may be used as a novel anti-cancer strategy. Hepatocellular carcinoma (HCC) is a deadly malignancy with poor chances of survival and is the second leading cause of cancer deaths worldwide. Diagnosis at an already late stage and general resistance to current therapies may be responsible for the dismal outcome. As the liver acts as a key factor in iron metabolism, ferroptosis is shown to play an important role in HCC carcinogenesis and, more importantly, may hold the potential to eradicate HCC. In this review, we summarize the current knowledge we have of the role of ferroptosis in HCC and the application of ferroptosis as a therapy option and provide an overview of the potential translation of ferroptosis in the clinical practice of HCC.

Predictive biomarkers for systemic therapy of hepatocellular carcinoma

Introduction: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the third cancer-related cause of death worldwide. In recent years, several systemic therapy drugs including sorafenib, lenvatinib, regorafenib, cabozantinib, ramucicurab, nivilumab, and pembrolizumab have been approved by FDA for advanced HCC. However, their insufficient efficacy, toxicity, and drug resistance require clinically applicable and validated predictive biomarkers.Areas covered: Our review covers the recent advancements in the identification of proteomic/genomic/epigenomic/transcriptomic biomarkers for predicting HCC treatment efficacy with the use of multi-kinase inhibitors (MKIs), CDK4/6 inhibitors, and immune checkpoint inhibitors (ICIs). Alpha-fetoprotein, des-carboxyprothrombin, vascular endothelial growth factor, angiopoietin-2, and dysregulated MTOR, VEGFR2, c-KIT, RAF1, PDGFRβ have the potential of proteomic/genomic biomarkers for sorafenib treatment. Alanine aminotransferase, aspartate aminotransferase, and albumin-bilirubin grade can predict the efficacy of other MKIs. Rb, p16, and Ki-67, and genes involved in cell cycle regulation, CDK1-4, CCND1, CDKN1A, and CDKN2A have been proposed for CD4/6 inhibitors, while dysregulated TERT, CTNNB1, TP53 FGF19, and TP53 are found to be predictors for ICI efficacy.Expert opinion: There are still limited clinically applicable and validated predictive biomarkers to identify HCC patients who benefit from systemic therapy. Further prospective biomarker validation studies for HCC personalized systemic therapy are required.

Diamond Nanofilm Normalizes Proliferation and Metabolism in Liver Cancer Cells

Purpose

Surgical resection of hepatocellular carcinoma can be associated with recurrence resulting from the degeneration of residual volume of the liver. The objective was to assess the possibility of using a biocompatible nanofilm, made of a colloid of diamond nanoparticles (nfND), to fill the side after tumour resection and optimize its contact with proliferating liver cells, minimizing their cancerous transformation.

Methods

HepG2 and C3A liver cancer cells and HS-5 non-cancer cells were used. An aqueous colloid of diamond nanoparticles, which covered the cell culture plate, was used to create the nanofilm. The roughness of the resulting nanofilm was measured by atomic force microscopy. Mitochondrial activity and cell proliferation were measured by XTT and BrdU assays. Cell morphology and a scratch test were used to evaluate the invasiveness of cells. Flow cytometry determined the number of cells within the cell cycle. Protein expression in was measured by mass spectrometry.

Results

The nfND created a surface with increased roughness and exposed oxygen groups compared with a standard plate. All cell lines were prone to settling on the nanofilm, but cancer cells formed more relaxed clusters. The surface compatibility was dependent on the cell type and decreased in the order C3A >HepG2 >HS-5. The invasion was reduced in cancer lines with the greatest effect on the C3A line, reducing proliferation and increasing the G2/M cell population. Among the proteins with altered expression, membrane and nuclear proteins dominated.

Conclusion

In vitro studies demonstrated the antiproliferative properties of nfND against C3A liver cancer cells. At the same time, the need to personalize potential therapy was indicated due to the differential protein synthetic responses in C3A vs HepG2 cells. We documented that nfND is a source of signals capable of normalizing the expression of many intracellular proteins involved in the transformation to non-cancerous cells.

TDO2 Was Downregulated in Hepatocellular Carcinoma and Inhibited Cell Proliferation by Upregulating the Expression of p21 and p27

Background

Tryptophan-2,3-dioxygenase (TDO2) converts tryptophan into kynurenine in the initial limiting step of the kynurenine pathway. During the past decade, the overexpression of TDO2 has been found in various human tumors. However, the role of TDO2 in hepatocellular carcinoma is controversial, and we sought to clarify it in this study.

Methods

Western blot analysis and immunochemistry were used to detect the expression of TDO2 in human tissue specimens. The effect of TDO2 on cell proliferation in vitro was assessed using CCK8 and colony formation assays, and a xenograft mouse model was used to detect the effect of TDO2 on tumor growth in vivo. Flow cytometry was used to assess the cell cycle status.

Results

Low TDO2 expression was found in HCC and was associated with poor prognosis and adverse clinical outcomes. Conversely, TDO2 could restrain the proliferation of HCC cells in vivo and in vitro. Furthermore, TDO2 upregulated the expression of p21 and p27, inducing cell-cycle arrest.

Conclusions

The loss of TDO2 expression in HCC was correlated with a poor prognosis and adverse clinical outcomes. At the same time, TDO2 could restrain the growth of HCC in vivo and in vitro. The results indicate that TDO2 is a potential biomarker and therapeutic target for HCC.

Emerging treatment modalities for systemic therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has long been a major global clinical problem as one of the most common malignant tumours with a high rate of recurrence and mortality. Although potentially curative therapies are available for the early and intermediate stages, the treatment of patients with advanced HCC remains to be resolved. Fortunately, the past few years have shown the emergence of successful systemic therapies to treat HCC. At the molecular level, HCC is a heterogeneous disease, and current research on the molecular characteristics of HCC has revealed numerous therapeutic targets. Targeted agents based on signalling molecules have been successfully supported in clinical trials, and molecular targeted therapy has already become a milestone for disease management in patients with HCC. Immunotherapy, a viable approach for the treatment of HCC, recognizes the antigens expressed by the tumour and treats the tumour using the immune system of the host, making it both selective and specific. In addition, the pipeline for HCC is evolving towards combination therapies with promising clinical outcomes. More drugs designed to focus on specific pathways and immune checkpoints are being developed in the clinic. It has been demonstrated that some drugs can improve the prognosis of patients with HCC in first- or second-line settings, and these drugs have been approved by the Food and Drug Administration or are nearing approval. This review describes targeting pathways and systemic treatment strategies in HCC and summarizes effective targeted and immune-based drugs for patients with HCC and the problems encountered.

CLEC4s as Potential Therapeutic Targets in Hepatocellular Carcinoma Microenvironment

Immunosuppressive tumor microenvironment in hepatocellular carcinoma (HCC) is critical in tumor development. C-type (Ca²⁺ -dependent) lectin (CLEC) receptors, essential in innate pattern recognition, have potential regulatory effects on immune cell trafficking and modulatory effects on cancer cell activity. However, information on the expression and prognostic value of CLECs in HCC is scanty. Herein, we explored the potential role of CLECs in HCC based on TCGA, ONCOMINE, GEPIA, UALCAN, cBioPortal, Metascape, TRRUST, and TIMER databases. Results demonstrated a significantly higher mRNA level of CLEC4A and CLEC4L in HCC tissues than normal liver tissues. Contrarily, we found significantly low CLEC4G/H1/H2/M expression in HCC tissues. The IHC analysis revealed the following: Absence of CLEC4A/J/K/M in normal and liver cancer tissues; high CLEC4C expression in HCC tissues; low expression and zero detection of CLEC4D/E/H1/H2/L in HCC tissues and normal tissues, respectively. And the HepG2 and LX-2 were used to verify the expression level of CLEC4s via qRT-PCR in vitro. Furthermore, the expression of CLEC4H1 (ASGR1) and CLEC4H2 (ASGR2) exhibited a significant relation to clinical stages. However, the expression of CLEC4A, CLEC4D, CLEC4E, CLEC4J (FCER2), CLEC4K (CD207), CLEC4G, CLEC4H1, CLEC4M, and CLEC4H2 decreased with tumor progression. Patients expressing higher CLEC4H1/H2 levels had longer overall survival than patients exhibiting lower expression. Moreover, CLEC4A/D/E/J/K/G/H1/M/H2 had significant down-regulated levels of promoter methylation. The expression level of CLEC4s was correlated with the infiltration of B cells, CD8 + T cells, CD4 + T cells, macrophage cells, neutrophil cells, and dendritic cells. Functional analysis revealed the potential role of CLECL4s in virus infection, including COVID-19. Also, hsa-miR-4278 and hsa-miR-324-5p, two potential miRNA targets of CLEC4s, were uncovered. This article demonstrates that CLEC4 is crucial for the development of HCC and is associated with infiltration of various immune cells, providing evidence for new immunotherapy targets in HCC.

Experimental Models of Hepatocellular Carcinoma-A Preclinical Perspective

Hepatocellular carcinoma (HCC), the most frequent form of primary liver carcinoma, is a heterogenous and complex tumor type with increased incidence, poor prognosis, and high mortality. The actual therapeutic arsenal is narrow and poorly effective, rendering this disease a global health concern. Although considerable progress has been made in terms of understanding the pathogenesis, molecular mechanisms, genetics, and therapeutical approaches, several facets of human HCC remain undiscovered. A valuable and prompt approach to acquire further knowledge about the unrevealed aspects of HCC and novel therapeutic candidates is represented by the application of experimental models. Experimental models (in vivo and in vitro 2D and 3D models) are considered reliable tools to gather data for clinical usability. This review offers an overview of the currently available preclinical models frequently applied for the study of hepatocellular carcinoma in terms of initiation, development, and progression, as well as for the discovery of efficient treatments, highlighting the advantages and the limitations of each model. Furthermore, we also focus on the role played by computational studies (in silico models and artificial intelligence-based prediction models) as promising novel tools in liver cancer research.

Over-activation of EFTUD2 correlates with tumor propagation and poor survival outcomes in hepatocellular carcinoma

PURPOSE

Elongation factor Tu GTP-binding domain containing 2 (EFTUD2) is an essential constituent of U5 small nuclear ribonucleoproteins (snRNPs) and plays a crucial role in spliceosome activation and cancer. The mechanism of EFTUD2 on carcinogenesis and development of liver cancer still need further study.

METHODS

Bioinformatic analysis was performed to find differential expressed genes and related pathways. Western blotting and quantitative PCR assays were used to verify the EFTUD2 expression in HCC cell lines and tumor tissues of liver cancer patients. Transfection of shRNAs in SKHEP1 and Huh7 cell lines was conducted to explore the mechanisms of EFTUD2 in HCC. CCK-8 method, colony formation, and cell cycle detection kit were used to detect the proliferation. A tumor model in nude mice was used to explore the role of EFTUD2 in liver cancer in vivo.

RESULTS

Based on the tumor tissues and para-tumor tissues in our HCC patients, we identified EFTUD2 as highly expressed in HCC tissues (P < 0.001). Bioinformatic analysis from the TCGA database also supported this biological phenomenon (P = 1.911e-17). Furtherly, the results of clinical specimens and TCGA data suggested that higher EFTUD2 expression levels correlated with high histologic grades, high pathological grades, and poor survival prognoses in HCC patients. And knockdown of EFTUD2 suppressed cell proliferation and colony formation in vitro. In vivo, knockdown of EFTUD2 constrained the tumor growing and expansion derived from SKHEP1 cells and induced a decrease in the tumor volume and tumor weight resected from nude mice. Furthermore, RNA sequencing based on EFTUD2 knockdown revealed that EFTUD2 affected target genes concerned with the cell cycle. Flow cytometric analyses in the SKHEP1 cell model revealed that knockdown significantly suppressed cell cycle course and caused cell cycle arrest in the G1 phase. CyclinD1 proteins were also inhibited by knocking down of EFTUD2.

CONCLUSION

EFTUD2 is markedly overexpressed in HCC tumor tissues. High EFTUD2 expression in HCC patients is associated with clinical features. Moreover, we confirmed that EFTUD2 shows a pivotal role in HCC cell proliferation and cell cycle course and could be a possible therapeutic avenue in HCC through disturbing EFTUD2.

Silencing hepatitis B virus covalently closed circular DNA: The potential of an epigenetic therapy approach

Global prophylactic vaccination programmes have helped to curb new hepatitis B virus (HBV) infections. However, it is estimated that nearly 300 million people are chronically infected and have a high risk of developing hepatocellular carcinoma. As such, HBV remains a serious health priority and the development of novel curative therapeutics is urgently needed. Chronic HBV infection has been attributed to the persistence of the covalently closed circular DNA (cccDNA) which establishes itself as a minichromosome in the nucleus of hepatocytes. As the viral transcription intermediate, the cccDNA is responsible for producing new virions and perpetuating infection. HBV is dependent on various host factors for cccDNA formation and the minichromosome is amenable to epigenetic modifications. Two HBV proteins, X (HBx) and core (HBc) promote viral replication by modulating the cccDNA epigenome and regulating host cell responses. This includes viral and host gene expression, chromatin remodeling, DNA methylation, the antiviral immune response, apoptosis, and ubiquitination. Elimination of the cccDNA minichromosome would result in a sterilizing cure; however, this may be difficult to achieve. Epigenetic therapies could permanently silence the cccDNA minichromosome and promote a functional cure. This review explores the cccDNA epigenome, how host and viral factors influence transcription, and the recent epigenetic therapies and epigenome engineering approaches that have been described.

Prognostic and Clinical Implications of WNK Lysine Deficient Protein Kinase 1 Expression in Patients With Hepatocellular Carcinoma

BACKGROUND/AIM

Hepatocellular carcinoma (HCC) is a particularly malignant form of cancer prevalent throughout the world; however, there is a pressing need for HCC biomarkers to facilitate prognosis and risk assessment.

PATIENTS AND METHODS

This paper reports on the potential prognostic value of WNK lysine deficient protein kinase 1 (WNK1) in cases of HCC. We analyzed the expression of WNK1 at the mRNA level using omics data from the UALCAN database. We then verified our findings through the immunohistochemical (IHC) staining of various human cancer tissue as well as 59 HCC samples paired with corresponding normal tissues. The prognostic value of mRNA or protein expression by WNK1 was evaluated using the Kaplan-Meier method.

RESULTS

Initial screening results revealed significantly higher WNK1 expression levels in HCC tissue compared to normal tissue. Verification using the paired HCC samples confirmed that the expression of WNK1 was indeed significantly higher in HCC tissue samples than in adjacent normal tissues. High WNK1 expression levels were significantly correlated with clinicopathological variables, including gender and histologic grade. Kaplan-Meier survival analysis revealed that high WNK1 expression levels were associated with poor HCC prognosis. Finally, univariate and multivariate analysis identified WNK1 as a prognostic factor for TNM stage in cases of HCC.

CONCLUSION

In summary, WNK1 is overexpressed at the mRNA and protein levels, and correlated with poor prognosis. Thus, WNK1 expression could potentially be used as a biomarker in HCC prognosis.

Genomic Landscape of Liquid Biopsy for Hepatocellular Carcinoma Personalized Medicine

Hepatocellular carcinoma (HCC) is the sixth most frequently diagnosed cancer and the third leading cause of cancer-related deaths worldwide. Advanced-stage HCC patients have poor survival rates and this requires the discovery of novel clear biomarkers for HCC early diagnosis and prognosis, identifying risk factors, distinguishing HCC from non-HCC liver diseases, and assessment of treatment response. Liquid biopsy has emerged as a novel minimally invasive approach to enable monitoring tumor progression, metastasis, and recurrence. Since the liquid biopsy analysis has relatively high specificity and low sensitivity in cancer early detection, there is a risk of bias. Next-generation sequencing (NGS) technologies provide accurate and comprehensive gene expression and mutational profiling of liquid biopsies including cell-free circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and genomic components of extracellular vesicles (EVs) including micro-RNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). Since HCC is a highly heterogeneous cancer, HCC patients can display various genomic, epigenomic, and transcriptomic patterns and exhibit varying sensitivity to treatment options. Identification of individual variabilities in genomic signatures in liquid biopsy has the potential to greatly enhance precision oncology capabilities. In this review, we highlight and critically discuss the latest progress in characterizing the genomic landscape of liquid biopsy, which can advance HCC personalized medicine.

The Epigenetic Modulation of Cancer and Immune Pathways in Hepatitis B Virus-Associated Hepatocellular Carcinoma: The Influence of HBx and miRNA Dysregulation

Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HBV-HCC) pathogenesis is fueled by persistent HBV infection that stealthily maintains a delicate balance between viral replication and evasion of the host immune system. HBV is remarkably adept at using a combination of both its own, as well as host machinery to ensure its own replication and survival. A key tool in its arsenal, is the HBx protein which can manipulate the epigenetic landscape to decrease its own viral load and enhance persistence, as well as manage host genome epigenetic responses to the presence of viral infection. The HBx protein can initiate epigenetic modifications to dysregulate miRNA expression which, in turn, can regulate downstream epigenetic changes in HBV-HCC pathogenesis. We attempt to link the HBx and miRNA induced epigenetic modulations that influence both the HBV and host genome expression in HBV-HCC pathogenesis. In particular, the review investigates the interplay between CHB infection, the silencing role of miRNA, epigenetic change, immune system expression and HBV-HCC pathogenesis. The review demonstrates exactly how HBx-dysregulated miRNA in HBV-HCC pathogenesis influence and are influenced by epigenetic changes to modulate both viral and host genome expression. In particular, the review identifies a specific subset of HBx induced epigenetic miRNA pathways in HBV-HCC pathogenesis demonstrating the complex interplay between HBV infection, epigenetic change, disease and immune response. The wide-ranging influence of epigenetic change and miRNA modulation offers considerable potential as a therapeutic option in HBV-HCC.

Attenuation of diethyl nitrosamine-induced hepatocellular carcinoma by taxifolin and/or alogliptin: The interplay between toll-like receptor 4, transforming growth factor beta-1, and apoptosis

Hepatocellular carcinoma (HCC) is the most common form of liver malignancies worldwide. Alogliptin is an anti-diabetic that may have effective anticancer properties against many types of malignancies. Taxifolin is a flavonoid that has potent antioxidant, and anti-inflammatory properties. The objective of this study was to explore the impact of alogliptin and/or taxifolin on diethyl nitrosamine-induced HCC in rats. One hundred male Wistar rats were divided into five equal groups as follows: Control; HCC; HCC + Alogliptin; HCC + Taxifolin; and HCC + Alogliptin + Taxifolin group. The survival rate, liver function tests, tissue antioxidant enzymes, malondialdehyde (MDA), nuclear factor (erythroid derived 2)-like 2 (Nrf2), transforming growth factor beta 1 (TGF-β1), interleukin 1 alpha (IL-1α), and toll-like receptor 4 (TLR4) were measured. Also, hepatic caspase 3, caspase 9, beclin-1, and c-Jun NH2-terminal kinase (JNK) in addition to serum alpha-fetoprotein (AFP) and α-L-Fucosidase (AFU) were assessed. Specimens of the liver were subjected to histopathological examination. Alogliptin and/or taxifolin induced significant improvement of liver function tests with significant increase in the survival rate, tissue antioxidant enzymes, Nrf2, caspase 3, caspase 9, Beclin-1 and JNK activities associated with significant decrease in serum AFP and AFU, tissue MDA, TGF-β1, IL-1α and TLR4 expression compared to HCC group. These results were significant with taxifolin/alogliptin combination when compared to the use of each of these agents alone. In conclusion, taxifolin/alogliptin combination might be used as adjuvant therapy for attenuation of HCC.

Immunmodulatory Treatment Strategies of Hepatocellular Carcinoma: From Checkpoint Inhibitors Now to an Integrated Approach in the Future

Simple Summary

Hepatocellular carcinoma (HCC) is among the most common cancer diseases worldwide and has only limited treatment options at advanced disease stages. Activation of the immune system with checkpoint inhibitors has revolutionized cancer medicine and has become important also for HCC treatment. Here, we summarize the current status of immunotherapy options for HCC and highlight how combination with locoregional therapies could improve the outcome of patients. Novel pathways and targets for immunologic drug development are briefly discussed that could help to increase the response rate of these approaches in HCC.

Abstract

Background: Hepatocellular carcinoma (HCC) still represents a human tumor entity with very limited therapeutic options, especially for advanced stages. Here, immune checkpoint modulating drugs alone or in combination with local ablative techniques could open a new and attractive therapeutic “door” to improve outcome and response rate for patients with HCC. Methods: Published data on HCC experimental to pre-(clinical) treatment strategies from standard of care to novel immunomodulatory concepts were summarized and discussed in detail. Results: Overall, our knowledge of the role of immune checkpoints in HCC is dramatically increased in the last years. Experimental and pre-clinical findings could be translated to phase 1 and 2 clinical trials and became standard of care. Local ablative techniques of HCC could improve the effectivity of immune checkpoint inhibitors in situ. Conclusions: This review demonstrates the importance of immunomodulatory treatment strategies of HCC, whereby the “best treatment code” of immune checkpoint drugs, combination with ablative techniques and of timing must be evaluated in coming clinical trials.

Romidepsin hepatocellular carcinoma suppression in mice is associated with deregulated gene expression of bone morphogenetic protein and Notch signaling pathway components

Recently, our group showed that Romidepsin, a histone deacetylase inhibitor (HDACi), suppressed diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in mice. In the present study, we investigated the effect of Romidepsin-treatment on gene expression levels of components of Bmp and Notch signaling pathways, which are both known to be aberrantly regulated in hepatocarcinogenesis. Total RNA from liver tissue samples and paraffin-embedded livers were retrieved from a recent experiment where C57BL/6 mice were treated with Romidepsin 10 months after DEN challenge and sacrificed 2 months later. RT qPCR was used for quantification of gene expression and immunohistochemistry for in situ protein detection. Regarding Bmp pathway, Romidepsin HCC-suppression was found to correlate significantly with Bmp2 and Bmp7 ligand up- and down-regulation, respectively. Intracellularly, Romidepsin-treated HCC mice exhibited a significant elevation of Bmp-inhibitor Smurf2 and Bmp-target gene Id3, as compared to the HCC untreated controls. Concerning Notch signaling, higher expression levels of ligands Jag1/Dll4, accompanied by a decreased expression of receptor Notch2, were identified in the Romidepsin-treated group. Τhe anti-oncogenic effect of Romidepsin, also correlated significantly with an increased expression of Hes1 target, as well as an up- and down-regulation of Klf4 and Sox9 transcription factors, respectively. Moreover, the cancer-related genes Snai2 and p21, known to be involved in many signaling pathways, including Bmp and Notch, were also found to be downregulated in Romidepsin-treated mice. Romidepsin HCC suppression is associated with gene expression deregulation of selective components of both Bmp and Notch signaling cascades.

Optimizing the Combination of Immunotherapy and Trans-Arterial Locoregional Therapy for Stages B and C Hepatocellular Cancer

Hepatocellular carcinoma (HCC), the most common primary hepatic malignancy worldwide, is the second leading cause of cancer-related death. Underlying liver dysfunction and advanced stage of disease require treatments to be optimally timed and implemented to minimize hepatic parenchymal damage while maximizing disease response and quality of life. Locoregional therapies (LRTs) such as trans-arterial chemo- and radio-embolization remain effective for intermediate liver-only and advanced HCC disease (i.e., Barcelona-Clinic liver cancer stages B and C) not amendable to primary resection or ablation. Additionally, these minimally invasive interventions have been shown to augment the immune system. This and the recent success of immune-oncologic treatments for HCC have generated interest in applying these therapies in combination with such locoregional interventions to improve patient outcomes and response rates. This report reviews the use of trans-arterial LRTs with immunotherapy for stages B and C HCC, potential biomarkers, and imaging methods for assessing the response and safety of such combinations.

CSN1 facilitates proliferation and migration of hepatocellular carcinoma cells by upregulating cyclin A2 expression

Constitutive photomorphogenesis 9 signalosome subunit 1 (CSN1) plays an important role in the ubiquitin-proteasome pathway and regulates various cellular processes, such as the cell cycle and DNA repair. The CSN complex consists of eight subunits (CSN1 to CSN8) and regulates the tumorigenesis of a variety of tumor types. However, the exact role of CSN1 in hepatocellular carcinoma (HCC) remains unclear. The present study evaluated the expression and biological effects of CSN1 in HCC tissue samples and cell lines. CSN1 was significantly overexpressed in HCC tissue and cell lines, compared with their normal counterparts. In patients with HCC, elevated CSN1 levels correlated with tumor size, tumor metastasis and tumor stage. Loss‑of‑function assays indicated that CSN1 knockdown inhibited the proliferation and migration HCC cells. In addition, CSN1 promoted the expression of cyclin A2 in a ubiquitination‑independent manner. Lastly, xenograft experiments indicated that CSN1 promoted HCC tumor growth in vivo. The present study suggested that CSN1 inhibition could represent a potential approach for the prevention of HCC progression and metastasis.

SPC25 overexpression promotes tumor proliferation and is prognostic of poor survival in hepatocellular carcinoma

Background: The nuclear division cycle 80 (NDC80) complex assures proper chromosome segregation during the cell cycle progression. SPC25 is a crucial component of NDC80, and its role in hepatocellular carcinoma (HCC) has been explored recently. This study characterized the differential expression of SPC25 in HCC patients of different races and HBV infection status.

Methods: Expression patterns of SPC25 were evaluated in TCGA and Chinese HCC patients. Kaplan-Meier analysis was applied to examine the predictive value of SPC25. In vitro and in vivo functional assays were conducted to explore the role of SPC25 in HCC. Bioinformatics methods were applied to investigate the regulatory mechanisms of SPC25.

Findings: The mRNA levels of SPC25 were up-regulated in HCC. SPC25 has a significantly higher transcriptional level in Asian patients than Caucasian patients. SPC25 promoted HCC cell proliferation in vitro and tumor growth in vivo by accelerating the cell cycle. We identified transcription factors, miRNAs, and immune cells that may interact with SPC25.

Interpretation: The findings suggest that increased expression of SPC25 is associated with poor prognosis of HCC and enhances the proliferative capacity of HCC cells. SPC25 could serve as a valuable prognostic marker and a novel treatment target for HCC.

Effect of isoform-specific HIF-1α and HIF-2α antisense oligonucleotides on tumorigenesis, inflammation and fibrosis in a hepatocellular carcinoma mouse model

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. For advanced HCC, there is still an unmet need for more effective therapeutic strategies. HCC is typically associated with hypoxia and the hypoxia-inducible factor (HIF) regulatory pathway plays an important role in HCC development and progression. Therefore, we investigated the therapeutic potential of isoform-specific HIF-1α and HIF-2α antisense oligonucleotides (ASOs), along with their effect on the inflammatory and fibrotic component of the tumor microenvironment (TME), in an experimental HCC mouse model. Based on its efficacy and safety, a dosage regimen of 20 mg/kg intraperitoneal injection of HIFα ASO twice per week was selected for further investigation in a preventive and therapeutic setting in a N,N-diethylnitrous amide (DEN)-induced HCC mouse model. DEN administration resulted in 100% tumor formation and HIFα ASO administration led to effective and selective hepatic downregulation of its target genes. HIFα ASO treatment had no effect on tumor numbers, but even enhanced the increased hepatic expression of HCC tumor markers, α-fetoprotein and glypican-3, compared to scrambled control ASO treatment in HCC mice. Especially HIF-1α ASO treatment resulted in an enhanced increase of monocytes and monocyte-derived macrophages in the liver and an enhanced hepatic upregulation of inflammatory markers. Both HIFα ASOs aggravated liver fibrosis in HCC mice compared to scrambled ASO treatment. The observed effects of our dosing regimen for HIF-1α and HIF-2α ASO treatment in the DEN-induced HCC mouse model discourage the use of HIFα isoforms as targets for the treatment of HCC.

The Angiopoietin/Tie2 Pathway in Hepatocellular Carcinoma

Due to the usually late diagnosis and lack of effective therapies, hepatocellular carcinoma (HCC), which poses a growing global health problem, is characterized by a poor prognosis. Angiogenesis plays an important role in HCC progression, and vascular endothelial growth factor (VEGF) and angiopoietins (Angs) are key drivers of HCC angiogenesis. VEGF-targeting strategies already represent an important component of today’s systemic treatment landscape of HCC, whereas targeting the Ang/Tie2 signaling pathway may harbor future potential in this context due to reported beneficial anticancer effects when targeting this pathway. In addition, a better understanding of the relation between Angs and HCC angiogenesis and progression may reveal their potential as predictive factors for post-treatment disease progression and prognosis. In this review, we give a comprehensive overview of the complex role of Ang/Tie2 signaling in HCC, pinpointing its potential value as biomarker and target for HCC treatments, aiding HCC diagnosis and therapy.

Radiation-induced H3K9 methylation on E-cadherin promoter mediated by ROS/Snail axis : Role of G9a signaling during lung epithelial-mesenchymal transition

Lung cancer patients who have undergone radiotherapy developed severe complications such as pneumonitis and fibrosis. Upon irradiation, epithelial cells acquire mesenchymal phenotype via a process called epithelial to mesenchymal transition (EMT), which plays a vital role in organ fibrosis. Several mechanisms have been studied on EMT, however, the correlation between radiation-induced EMT and epigenetic changes are not well known. In the present study, we investigated the role of histone methyltransferase G9a on radiation-induced EMT signaling. There was an increase in total global histone methylation level in irradiated epithelial cells. Western blot analysis on irradiated cells showed an increased expression of H3K9me2/3. The pre-treatment of G9a inhibitor enhanced E-cadherin expression and decreased the mesenchymal markers like N-cadherin, vimentin in the radiated group. Surprisingly, radiation-induced ROS generation and pERK1/2 levels were also inhibited by G9a inhibitor BIX01294, which is showing its antioxidant potential. The ChIP-qPCR analysis on the E-cadherin promoter suggested that G9a and Snail might have formed complex to enrich suppressive marker H3K9me2/3. On the whole, our present study suggested that 1] ROS could modify H3K9 methylation via G9a and promote radiation-induced lung EMT in Beas2B and A549 cells 2] E-cadherin promoter enrichment with heterochromatin mark H3K9me2 expression upon irradiation could be modified by regulating G9a methyltransferase.

Long non-coding RNA BCAR4 promotes liver cancer progression by regulating proliferation, migration and invasion

Liver cancer (LC) is one of the primary contributors of cancer-associated death worldwide. Long non-coding RNAs (lncRNAs) have been shown to participate in almost every aspect of cell biology and serve fundamental roles in carcinogenesis and cancer progression, including in LC. However, the clinical significance and functional role of the lncRNA breast cancer anti-estrogen resistance 4 (BCAR4) in LC have not yet been identified. The present study measured the expression levels of BCAR4 in LC cells and tissues, and discovered that BCAR4 was upregulated in LC tissues compared with adjacent normal tissues. Furthermore, high BCAR4 expression was associated with the presence of multiple tumors and advanced Tumor-Node-Metastasis stages (III/IV). Survival analysis found that high BCAR4 expression indicated poor overall survival (OS) and progression-free survival (PFS). By analyzing the risk factors of poor OS and PFS using univariate analysis and multivariate analysis, high BCAR4 expression was revealed to be an independent risk factor of poor prognosis. In addition, the role of BCAR4 was further investigated in vitro, which revealed overexpression of BCAR4 to markedly promote the proliferation, migration and invasion of LC cells. Conversely, the loss of BCAR4 expression repressed the proliferation, migration and invasion of LC cells. In conclusion, BCAR4 is overexpressed in LC and is associated with LC progression. Therefore, BCAR4 may be used as a potential prognostic marker in LC.

HDAC1/2 Inhibitor Romidepsin Suppresses DEN-Induced Hepatocellular Carcinogenesis in Mice

Background

Hepatocellular carcinoma (HCC) is a frequently diagnosed cancer and a leading cause of cancer-related death worldwide. Its rapid progression, combined with the limited treatment options at late stages, imposes the need for early detection and aggressive intervention. Based on the knowledge that hepatocarcinogenesis is significantly influenced by histone acetylation, we directed our search for novel HCC therapeutics among histone deacetylation inhibitors (HDACi). The aim of the present study was to investigate the effect of HDAC1/2 inhibitor Romidepsin in the well-established mouse model of diethylnitrosamine (DEN)-induced HCC.

Materials and Methods

C56BL/6 mice were treated with Romidepsin at the critical point of 10 months after DEN challenge and their livers were examined 2 months later using histopathology and morphometry. Protein levels were assessed in serum using ELISA and in liver tissues using Western blot and immunohistochemistry (in-situ detection). Gene expression was quantified using real-time PCR.

Results

Romidepsin suppressed cancer progression. This effect was associated with decreased proliferation and increased apoptosis of cancer cells. The cell cycle regulator CK2a, the anti-inflammatory molecule PPAR-γ, and the tumor suppressors PTEN and CYLD were upregulated in treated HCC. By contrast, the expression of PI3K, NF-κB p65 and c-Jun was reduced. In line with this result, the levels of two major apoptosis regulators, ie, BAD and the multifunctional protein c-Met, were lower in the blood serum of treated mice compared to the untreated mice with HCC.

Conclusion

These findings suggest that Romidepsin, a drug currently used in the treatment of lymphoma, could also be considered in the management of early-stage HCC.

Diosmetin Inhibits Cell Proliferation, Induces Cell Apoptosis and Cell Cycle Arrest in Liver Cancer

Objective

Diosmetin (DIOS) has been confirmed to possess anti-cancer effects in some types of tumors. However, it remains unclear whether DIOS exerts anti-cancer effects on liver cancer. Thus, our purpose was to observe the effect of DIOS on cell proliferation, cell apoptosis and cell cycle arrest in human liver cancer cells.

Materials and Methods

The cell viability of HepG2 and HCC-LM3 cells under different concentrations of DIOS was detected using MTT assay. The cell apoptosis and cell cycle arrest were analyzed by flow cytometry. The expression levels of apoptosis/cell cycle-related proteins including P53, Bcl-2, Bax, cleaved-caspase3, cleaved-caspase8, cleaved-PARP, Bak, cdc2, cyclinB1 and P21 were measured using Western blot. HepG2 cells were transfected by checkpoint kinase 1 (Chk1)-small interfering RNA (siRNA) and checkpoint kinase 2 (Chk2)-siRNA, respectively. After that, cell cycle was detected.

Results

DIOS significantly suppressed cell proliferation and induced cell apoptosis of HepG2 cells and HCC-LM3 cells. Moreover, DIOS promoted cell cycle arrest in G2/M phase. Western blot results showed that DIOS significantly suppressed the expression levels of Bcl-2, cdc2, cyclinB1, and promoted the expression levels of Bax, cleaved-caspase3, cleaved-caspase8, cleaved-PARP, Bak, P53, and P21. The G2/M phase arrest was observed in HepG2 cells transfected with Chk2-siRNA, while the G2/M phase arrest was not obvious in HepG2 cells transfected with Chk1-siRNA.

Conclusion

Our findings revealed that DIOS could inhibit cell proliferation and promote cell apoptosis and cell cycle arrest in liver cancer. Furthermore, DIOS could induce G2/M cell cycle arrest in HepG2 cell via targeting Chk2.

SNHG5 functions as competitive RNA with miR-23c to regulate HMGB2 expression in hepatocellular carcinoma

Emerging evidence demonstrated long non-coding RNA (lncRNA) small nucleolar RNA host gene 5 (SNHG5) participates in the tumorigenesis. The aim of this work was to characterize the expression and biology roles of SNHG5 in hepatocellular carcinoma (HCC). Expression level of SNHG5 in HCC cells was analyzed with RT-qPCR. Cell proliferation rate, cell cycle distribution, and cell migration ability was analyzed with cell counting kit-8 assay, flow cytometry, and wound-healing assay, respectively. Targets prediction were performed at LncBase V2.0 and TargetScan. SNHG5 was found elevated expression in HCC cell lines. In vitro functional experiments showed knockdown of SNHG5 inhibits cell proliferation and migration, while overexpression of SNHG5 exerted opposite effects. Mechanism studies showed SNHG5 functions as competitive endogenous RNA (ceRNA) for microRNA-23c (miR-23c) to promote high mobility group box 2 (HMGB2) expression. miR-23c was downregulated, while HMGB2 was upregulated in HCC tissues and cells. We revealed SNHG5 could exert an oncogenic role in HCC via regulating miR-23c/HMGB2 axis. Targeting SNHG5 might be a novel therapeutic measure to suppresses HCC progression.

Role of pyroptosis in liver diseases

Pyroptosis is known as a novel form of pro-inflammatory cell death program, which is exceptional from other types of cell death programs. Particularly, pyroptosis is characterized by Gasdermin family-mediated pore formation and subsequently cellular lysis, also release of several pro-inflammatory intracellular cytokines. In terms of mechanism, there are two signaling pathways involved in pyroptosis, including caspase-1, and caspase-4/5/11 mediated pathways. However, pyroptosis plays important roles in immune defense mechanisms. Recent studies have demonstrated that pyroptosis plays significant roles in the development of liver diseases. In our review, we have focused on the role of pyroptosis based on the molecular and pathophysiological mechanisms in the development of liver diseases. We have also highlighted targeting of pyroptosis for the therapeutic implications in liver diseases in the near future.

A novel miR-0308-3p revealed by miRNA-seq of HBV-positive hepatocellular carcinoma suppresses cell proliferation and promotes G1/S arrest by targeting double CDK6/Cyclin D1 genes

Background

Persistent infection with hepatitis B virus (HBV) accounts for the majority of hepatocellular carcinoma (HCC), but the molecular mechanisms underlying liver carcinogenesis are still not completely understood. Increasing evidence demonstrates that microRNAs (miRNAs) play significant functional roles in virus–host interactions. The aim of this study was to explore differentially expressed miRNA profiles and investigate the molecular mechanism of miR-0308-3p in HBV-positive HCC carcinogenesis.

Methods

High-throughput sequencing was used to detect novel miRNAs in three samples of HBV-positive HCC tissue compared to matched HBV-negative HCC tissue. The Cancer Genome Atlas (TCGA) database was used to mine miRNAs related to HBV-positive HCC. Bioinformatics analyses were conducted to predict the miRNAs’ possible biological and pathway regulatory functions. Quantitative polymerase chain reaction (qPCR) was then applied to evaluate the expression levels of randomly selected miRNAs. CCK-8 was used to measure cell proliferation and cell cycles were analyzed using flow cytometry. A dual luciferase reporter gene assay was used to confirm the downstream targets of miR-0308-3p.

Results

In total, there were 34 overlapping miRNAs in both our miRNA-seq data and the TCGA database. We found two overlapping miRNAs in both the HBV-positive HCC samples and the TCGA database, and 205 novel pre-miRNA sequences were predicted. miR-522 and miR-523 were markedly overexpressed in HBV-positive HCC and were associated with a significantly poorer long-term prognosis (miR-522, HR 2.19, 95% CI 1.33–3.6, p = 0.0015; miR-523HR 1.5, 95% CI 1–2.44, p = 0.0047). Of note, we found that the novel miR-0308-3p was markedly downregulated in HBV-positive HCC samples and HCC cancer cell lines compared with HBV-negative HCC samples and adjacent normal hepatic tissue. Moreover, elevated expression of miR-0308-3p was found to inhibit proliferation of cancer cells by promoting G1/S cell cycle arrest but did not influence the apoptosis of cancer cells. A dual luciferase reporter activity assay identified that miR-0308-3p acted directly on the target sequence of the CDK6 and Cyclin D1 mRNA 3ʹUTR to suppress CDK6 and Cyclin D1 expression.

Conclusions

MiR-0308-3p upregulation dramatically suppressed HCC cell proliferation and induced G1/S cell cycle arrest by directly targeting CDK6/Cyclin D1. These findings reveal a novel molecular mechanism for activation of G1/S arrest in HCC and may prove clinically useful for developing new therapeutic targets.

The role of the innate immune system in the development and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Most patients present with advanced or metastatic HCC at diagnosis and face a dismal prognosis. Tyrosine kinases are the gold standard treatment for this disease but yield limited survival benefits. Immune checkpoint inhibitors that augment adaptive immunity have been tested in HCC. Complex interactions between tumor cells, lymphocytes and the tumor environment determine the efficacy of such immunotherapies. Innate immune mechanisms – known drivers of liver disease progression in pre-HCC conditions such as fibrosis or cirrhosis – may either support or counteract tumor-related immune activation. In this review, we will highlight current concepts of the role of the innate immune system in hepatocarcinogenesis and discuss their relevance for translation into clinics.

Mitofusin-2 (Mfn-2) Might Have Anti-Cancer Effect through Interaction with Transcriptional Factor SP1 and Consequent Regulation on Phosphatidylinositol Transfer Protein 3 (PITPNM3) Expression

BACKGROUND The aim of this study was to explore the influence of mitofusin-2 (Mfn-2) on phosphatidylinositol transfer protein 3 (PITPNM3) and tumor growth and the potential mechanism behind the regulation of Mfn-2 on PITPNM3 in hepatic carcinoma cell line SMMC-7721. MATERIAL AND METHODS We obtained promoter sequence of PITPNM3 gene from University of Santa Cruz (UCSC) genomic database, and we predict transcriptional factor of PITPNM3 genes by JASPAR database. Target transcription factor was determined by comparison of binding sites number for promoter. SMMC-7721 cells were transfected with expression plasmid containing Mfn-2, transcription factor gene and PITPNM3. The cells transfected with empty vector were used as control. Real-time polymerase chain reaction was used to determine the mRNA level of target genes. Co-immunoprecipitation (Co-IP) assay was used to determine the interaction between Mfn-2 and target transcription factor. Chromatin immunoprecipitation assay (ChIP) assay was used to determine the binding of transcription factor with PITPNM3 promoter. Tumorigenicity assay was used to compare the effect of Mfn-2, SP1, and PITPNM3 on tumor development. RESULTS SP1 was selected as the target transcriptional factor. In the Co-IP assay, Mfn-2 was shown to interact with SP1. In the ChIP assay Mfn-2 transfection resulted in decreased binding number of SP1 with PITPNM3 promoter. Furthermore, PITPNM3 mRNA levels were significantly increased in SMMC-7721 cells transfected with SP1 but were decreased after transfection with Mfn-2. In nude mice, PITPNM3 and SP1 upregulation lead to larger tumor lump and conversely Mfn-2 upregulation lead to smaller tumor lump. CONCLUSIONS Mfn-2 could suppress expression of PITPNM3 through interaction with transcription factor SP1; Mfn-2 may have anti-tumor activity; SP1 and PITPNM3 may promote tumor development.

The Effect of Protein FAM172A on Proliferation in HepG2 Cells and Investigation of the Possible Molecular Mechanism

Background

In our previous study, we found that the FAM172A recombinant protein could promote proliferation of L02 cells. However, the underlying mechanisms are still unknown. The present study was aimed at investigating the effect of FAM172A on proliferation of HepG2 cells and exploring the possible molecular mechanisms and its role in hepatocellular carcinoma (HCC).

Methods

Cell proliferation was measured by MTT assay. Western blot test was carried out to investigate the mechanism. Rabbit antibodies against FAM172A and membrane proteins isolated from lysate of HepG2 cell were coprecipitated and the resultant precipitates were analyzed by mass spectrum.

Results

The MTT assay showed that recombinant protein FAM172A isoform 1 (FAM172A-1) could induce HepG2 cell proliferation at the concentration of 10-100 ng/mL, while protein FAM172A isoform 3 (FAM172A-3) was at the concentration of 80-100 ng/mL. Western blot demonstrated that both FAM172A-1 and FAM172A-3 could activate the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) pathway and the phosphatidylinositol 3-kinase/threonine-protein kinase (PI3K/Akt) pathway. Mass spectrum analysis suggested that there were some membrane proteins interacting with FAM172A. Several candidate interacting proteins might mediate proliferation signals induced by FAM172A recombinant protein, including seven membrane proteins.

Conclusion

In conclusion, FAM172A recombinant protein could induce proliferation of HepG2 cells, in which the MAPK/ERK and PI3K/Akt signaling pathways might be involved. The role of FAM172A in HepG2 cell proliferation also indicated its possible involvement in HCC. The receptor of FAM172A on cells still needs to be exploited.

The Crosstalk of miRNA and Oxidative Stress in the Liver: From Physiology to Pathology and Clinical Implications

The liver is the central metabolic organ of mammals. In humans, most diseases of the liver are primarily caused by an unhealthy lifestyle-high fat diet, drug and alcohol consumption- or due to infections and exposure to toxic substances like aflatoxin or other environmental factors. All these noxae cause changes in the metabolism of functional cells in the liver. In this literature review we focus on the changes at the miRNA level, the formation and impact of reactive oxygen species and the crosstalk between those factors. Both, miRNAs and oxidative stress are involved in the multifactorial development and progression of acute and chronic liver diseases, as well as in viral hepatitis and carcinogenesis, by influencing numerous signaling and metabolic pathways. Furthermore, expression patterns of miRNAs and antioxidants can be used for biomonitoring the course of disease and show potential to serve as possible therapeutic targets.