Resminostat plus sorafenib as second-line therapy of advanced hepatocellular carcinoma - The SHELTER study

Histone modification inhibitors: An emerging frontier in thyroid Cancer therapy

Thyroid cancer (TC) is the most common endocrine cancer and is a serious health concern due to its aggressiveness and high incidence. Histone modifications affect DNA accessibility and gene transcriptional activity by altering the structure of chromatin. Abnormal histone modifications may affect genome stability and disrupt gene expression patterns, leading to many diseases, including cancer. A growing body of research suggests that histone modifications and TC progression are inextricably linked. This article discusses the impact of aberrant histone modification patterns on TC. By targeting specific histone-modifying enzymes, it may be possible to regulate gene expression and inhibit the growth of TC. Finally, we summarize the relevant histone modification inhibitors to better understand the development stage of the use of these drugs to inhibit histone-modifying enzymes in cancer treatment.

Epigenetic regulation of ferroptosis in gastrointestinal cancers (Review)

Ferroptosis is a type of iron‑dependent cell death characterized by excessive lipid peroxidation and may serve as a potential therapeutic target in cancer treatment. While the mechanisms governing ferroptosis continue to be explored and elucidated, an increasing body of research highlights the significant impact of epigenetic modifications on the sensitivity of cancer cells to ferroptosis. Epigenetic processes, such as DNA methylation, histone modifications and non‑coding RNAs, have been identified as key regulators that modulate the expression of ferroptosis‑related genes. These alterations can either enhance or inhibit the sensitivity of gastrointestinal cancer (GIC) cells to ferroptosis, thereby affecting the fate of GICs. Drugs that target epigenetic markers for advanced‑stage cancer have shown promising results in enhancing ferroptosis and inhibiting tumor growth. This review explores the intricate relationship between epigenetic regulation and ferroptosis in GICs. Additionally, the potential of leveraging epigenetic modifications to trigger ferroptosis in GICs is investigated. This review highlights the importance of further research to elucidate the specific mechanisms underlying epigenetic control of ferroptosis and to advance the development of novel therapeutic approaches.

The epigenetic basis of hepatocellular carcinoma - mechanisms and potential directions for biomarkers and therapeutics

Hepatocellular carcinoma (HCC) is the sixth leading cancer worldwide and has complex pathogenesis due to its heterogeneity, along with poor prognoses. Diagnosis is often late as current screening methods have limited sensitivity for early HCC. Moreover, current treatment regimens for intermediate-to-advanced HCC have high resistance rates, no robust predictive biomarkers, and limited survival benefits. A deeper understanding of the molecular biology of HCC may enhance tumor characterization and targeting of key carcinogenic signatures. The epigenetic landscape of HCC includes complex hallmarks of 1) global DNA hypomethylation of oncogenes and hypermethylation of tumor suppressors; 2) histone modifications, altering chromatin accessibility to upregulate oncogene expression, and/or suppress tumor suppressor gene expression; 3) genome-wide rearrangement of chromatin loops facilitating distal enhancer-promoter oncogenic interactions; and 4) RNA regulation via translational repression by microRNAs (miRNAs) and RNA modifications. Additionally, it is useful to consider etiology-specific epigenetic aberrancies, especially in viral hepatitis and metabolic dysfunction-associated steatotic liver disease (MASLD), which are the main risk factors of HCC. This article comprehensively explores the epigenetic signatures in HCC, highlighting their potential as biomarkers and therapeutic targets. Additionally, we examine how etiology-specific epigenetic patterns and the integration of epigenetic therapies with immunotherapy could advance personalized HCC treatment strategies.

Insights into Sorafenib resistance in hepatocellular carcinoma: Mechanisms and therapeutic aspects

The most prevalent primary hepatic cancer, hepatocellular carcinoma (HCC), has a bad prognosis. HCC prevalence and related deaths have increased in recent decades. Food and Drug Administration (FDA) has licensed Sorafenib as a first-line treatment for individuals with advanced HCC. Despite this, some clinical studies indicate that a significant percentage of liver cancer patients exhibit insensitivity to sorafenib. Furthermore, the overall effectiveness of sorafenib is far from adequate, and the number of patients who benefit from therapy is low. In recent years, many researchers have focused on the mechanisms underlying sorafenib resistance. Acquired resistance to sorafenib in HCC cells has been reported to be facilitated by dysregulation of signal transducer and activator of transcription 3 (STAT3) activation, angiogenesis, autophagy, hypoxia-induced pathways, epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs), ferroptosis, and non-coding RNAs (ncRNAs). Recent clinical trials, including comparisons of sorafenib with immune checkpoint inhibitors like tislelizumab, have shown promise in improving patient outcomes. Additionally, combination therapies targeting complementary pathways are under investigation to overcome resistance and enhance treatment efficacy. The limitation of Sorafenib's effectiveness has been partially but not completely clarified. Furthermore, while certain regimens have demonstrated positive results, more clinical trials are required to confirm them. Future research should focus on identifying predictive biomarkers for therapy response, targeting the tumor microenvironment, and exploring novel therapeutic agents and personalized medicine strategies. A deeper understanding of these mechanisms will be essential for developing more effective therapeutic approaches and improving the prognosis of patients with advanced HCC. This article discusses strategies that may be employed to enhance the success of treatment and summarizes new research on the possible pathways that lead to sorafenib resistance.

Integrated analysis of single-cell RNA-seq and bulk RNA-seq unravels the molecular feature of tumor-associated neutrophils of head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a lethal malignancy with a high recurrence and distant metastasis rate, posing significant challenges to patient prognosis. Recent studies suggest that tumor-associated neutrophils (TANs) can modulate immune cell infiltration and influence tumor initiation and progression. However, the potential clinical significance of TANs in HNSCC remains insufficiently explored.

METHODS

TANs-specific marker genes were identified via single-cell sequencing data from HNSCC. Based on data from The Cancer Genome Atlas (TCGA), a prognostic risk model was constructed using TANs cell marker genes, and the model was validated with data from the Gene Expression Omnibus (GEO) database. The associations between the TANs signature and clinical characteristics, functional pathways, immune cell infiltration, immune checkpoint expression, and responses to immunotherapy and chemotherapy, were then investigated. Cell counting kit-8(CCK-8), Transwell, and wound healing assays were conducted to assess the functional role of TANs marker molecules.

RESULTS

TANs characteristic genes were identified from single-cell sequencing data from HNSCC patients. On the basis of these characteristic genes, a tumor-associated neutrophils-associated signature (NRS) was developed and validated across internal and external cross-platform cohorts through comprehensive procedures. The NRS demonstrated robust and reliable performance in predicting overall survival. Additionally, patients with a low NRS showed enhanced immune cell infiltration, active lipid metabolism, and increased sensitivity to immunotherapy. In contrast, patients with a high NRS exhibited poor prognostic outcomes, advanced clinical stages, and significant associations with HNSCC metastasis and progression. Furthermore, we identified a TANs-associated biomarker, OLR1, and validated that OLR1 promotes HNSCC proliferation, invasion, and migration through CCK-8, Transwell invasion, and wound healing assays.

CONCLUSION

This study has developed a promising TANs-based tool that may aid in personalized treatment and prognostic management for patients with HNSCC.

Mechanism and application of HDAC inhibitors in the treatment of hepatocellular carcinoma

Hepatoma is the sixth most malignant tumor in the world and the second leading cause of cancer death. Among the types of hepatoma, hepatocellular carcinoma (HCC) is the most important pathological type. For patients with early-stage HCC, the curative treatment is tumor resection. However, early diagnosis and treatment of HCC are difficult; the disease progresses rapidly, and the prognosis is poor. Due to the current limited treatment options for advanced HCC, the identification of new targeted agents is critical for the development of novel approaches to HCC treatment. Histone deacetylases (HDACs) is a protease that removes acetyl groups from histone lysine residues in proteins, and it plays an important role in the structural modification of chromosomes and the regulation of gene expression. Abnormally expressed HDACs can promote tumorigenesis by inducing biological processes such as cell proliferation, migration, and apoptosis inhibition. Since HDACs activity is upregulated in HCC, treatment regimens specifically inhibiting various HDACs have shown good efficacy. This article reviews the application of HDAC inhibitors in the treatment of HCC and explains their mechanisms of action. KEY MESSAGES: HDAC network and cellular effects of HDAC inhibitors. Role and mechanism of HDAC inhibitors in HCC. HDAC inhibitor combined with other ways to treat HCC. The side effects of HDACis in the treatment of HCC.

Drug resistance in TKI therapy for hepatocellular carcinoma: Mechanisms and strategies

Tyrosine kinase inhibitors (TKIs) are such as sorafenib the first-line therapeutic drugs for patients with advanced hepatocellular carcinoma. However, patients with TKI-resistant advanced liver cancer are insensitive to TKI treatment, resulting in limited survival benefits. This paper comprehensively reviewed the mechanisms underlying TKI resistance in hepatocytes, investigating activation of tumor signaling pathways, epigenetic regulation, tumor microenvironment, and metabolic reprogramming. Based on resistance mechanisms, it also reviews preclinical and clinical studies of drug resistance strategies and summarizes targeted therapy combined with immunotherapy currently in investigational clinical trials. Understanding the interactions and clinical studies of these resistance mechanisms offers new hope for improving and prolonging patient survival.

Evaluating Sorafenib (SORA-2) as Second-Line Treatment for Unresectable Hepatocellular Carcinoma: A European Retrospective Multicenter Study

BACKGROUND/OBJECTIVES

Systemic treatment for unresectable hepatocellular carcinoma (HCC) has rapidly advanced, with immune checkpoint inhibitors now the preferred first-line option. However, with multiple agents available and no established treatment sequence, selecting the most suitable second-line (2L) therapy remains challenging. While sorafenib is frequently chosen for 2L treatment, comprehensive data supporting its use is limited. This study evaluates the effectiveness of sorafenib as 2L therapy and factors influencing outcomes following first-line treatment failure in advanced HCC patients.

METHODS

This is a retrospective, multicenter study, including 81 patients with unresectable HCC from 12 European centers who received sorafenib as 2L treatment. Median overall survival (mOS), median progression-free survival (mPFS), radiological response to treatment, and toxicity were evaluated. Univariable and multivariable analyses were performed to identify potential predictors of clinical benefit.

RESULTS

In this cohort, some patients were treated with 2L sorafenib mOS for 7.4 months (95% CI: 6.6-13.6) and other patients were treated with mPFS for 3.7 months (95% CI: 3.0-4.8). Multivariable analysis revealed the best median OS for patients with CP A and AFP levels < 400 ng/mL (15.5 months). Adverse events (AE) of grade ≥ 3 were reported in 59.4% of patients.

CONCLUSIONS

In this real-world cohort of European patients with unresectable HCC, the outcome of sorafenib treatment in the 2L setting was comparable to that of the other established 2L treatment options in patients with preserved liver function and good performance status. This study contributes to the understanding of the role of sorafenib in the 2L setting and underscores the need for further research to identify predictive factors for response and survival in order to optimize treatment algorithms for advanced HCC.

Nuclear KRT19 is a transcriptional corepressor promoting histone deacetylation and liver tumorigenesis

BACKGROUND AND AIMS

Epigenetic reprogramming and escape from terminal differentiation are poorly understood enabling characteristics of liver cancer. Keratin 19 (KRT19), classically known to form the intermediate filament cytoskeleton, is a marker of stemness and worse prognosis in liver cancer. This study aimed to address the functional roles of KRT19 in liver tumorigenesis and to elucidate the underlying mechanisms.

APPROACH AND RESULTS

Using multiplexed genome editing of hepatocytes in vivo, we demonstrated that KRT19 promoted liver tumorigenesis in mice. Cell fractionation revealed a previously unrecognized nuclear fraction of KRT19. Tandem affinity purification identified histone deacetylase 1 and REST corepressor 1, components of the corepressor of RE-1 silencing transcription factor (CoREST) complex as KRT19-interacting proteins. KRT19 knockout markedly enhanced histone acetylation levels. Mechanistically, KRT19 promotes CoREST complex formation by enhancing histone deacetylase 1 and REST corepressor 1 interaction, thus increasing the deacetylase activity. ChIP-seq revealed hepatocyte-specific genes, such as hepatocyte nuclear factor 4 alpha ( HNF4A ), as direct targets of KRT19-CoREST. In addition, we identified forkhead box P4 as a direct activator of aberrant KRT19 expression in liver cancer. Furthermore, treatment of primary liver tumors and patient-derived xenografts in mice suggest that KRT19 expression has the potential to predict response to histone deacetylase 1 inhibitors especially in combination with lenvatinib.

CONCLUSIONS

Our data show that nuclear KRT19 acts as a transcriptional corepressor through promoting the deacetylase activity of the CoREST complex, resulting in dedifferentiation of liver cancer. These findings reveal a previously unrecognized function of KRT19 in directly shaping the epigenetic landscape in cancer.

Novel histone modifications and liver cancer: emerging frontiers in epigenetic regulation

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, and its onset and progression are closely associated with epigenetic modifications, particularly post-translational modifications of histones (HPTMs). In recent years, advances in mass spectrometry (MS) have revealed a series of novel HPTMs, including succinylation (Ksuc), citrullination (Kcit), butyrylation (Kbhb), lactylation (Kla), crotonylation (Kcr), and 2-hydroxyisobutyrylation (Khib). These modifications not only expand the histone code but also play significant roles in key carcinogenic processes such as tumor proliferation, metastasis, and metabolic reprogramming in HCC. This review provides the first comprehensive analysis of the impact of novel HPTMs on gene expression, cellular metabolism, immune evasion, and the tumor microenvironment. It specifically focuses on their roles in promoting tumor stem cell characteristics, epithelial-mesenchymal transition (EMT), and therapeutic resistance. Additionally, the review highlights the dynamic regulation of these modifications by specific enzymes, including "writers," "readers," and "erasers."

Hepatocellular carcinoma: signaling pathways and therapeutic advances

Liver cancer represents a major global health concern, with projections indicating that the number of new cases could surpass 1 million annually by 2025. Hepatocellular carcinoma (HCC) constitutes around 90% of liver cancer cases and is primarily linked to factors incluidng aflatoxin, hepatitis B (HBV) and C (HCV), and metabolic disorders. There are no obvious symptoms in the early stage of HCC, which often leads to delays in diagnosis. Therefore, HCC patients usually present with tumors in advanced and incurable stages. Several signaling pathways are dis-regulated in HCC and cause uncontrolled cell propagation, metastasis, and recurrence of HCC. Beyond the frequently altered and therapeutically targeted receptor tyrosine kinase (RTK) pathways in HCC, pathways involved in cell differentiation, telomere regulation, epigenetic modification and stress response also provide therapeutic potential. Investigating the key signaling pathways and their inhibitors is pivotal for achieving therapeutic advancements in the management of HCC. At present, the primary therapeutic approaches for advanced HCC are tyrosine kinase inhibitors (TKI), immune checkpoint inhibitors (ICI), and combination regimens. New trials are investigating combination therapies involving ICIs and TKIs or anti-VEGF (endothelial growth factor) therapies, as well as combinations of two immunotherapy regimens. The outcomes of these trials are expected to revolutionize HCC management across all stages. Here, we provide here a comprehensive review of cellular signaling pathways, their therapeutic potential, evidence derived from late-stage clinical trials in HCC and discuss the concepts underlying earlier clinical trials, biomarker identification, and the development of more effective therapeutics for HCC.

Epigenetic modification of hepatitis B virus infection and related hepatocellular carcinoma

Hepatitis B virus (HBV) infection poses a challenge to global public health. Persistent liver infection with HBV is associated with an increased risk of developing severe liver disease. The complex interaction between the virus and the host is the reason for the persistent presence of HBV and the risk of tumor development. Chronic liver inflammation, integration of viral genome with host genome, expression of HBx protein, and viral genotype are all key participants in the pathogenesis of hepatocellular carcinoma (HCC). Epigenetic regulation in HBV-associated HCC involves complex interactions of molecular mechanisms that control gene expression and function without altering the underlying DNA sequence. These epigenetic modifications can significantly affect the onset and progression of HCC. This review summarizes recent research on the epigenetic regulation of HBV persistent infection and HBV-HCC development, including DNA methylation, histone modification, RNA modification, non-coding RNA, etc. Enhanced knowledge of these mechanisms will offer fresh perspectives and potential targets for intervention tactics in HBV-HCC.

Epigenetics-targeted drugs: current paradigms and future challenges

Epigenetics governs a chromatin state regulatory system through five key mechanisms: DNA modification, histone modification, RNA modification, chromatin remodeling, and non-coding RNA regulation. These mechanisms and their associated enzymes convey genetic information independently of DNA base sequences, playing essential roles in organismal development and homeostasis. Conversely, disruptions in epigenetic landscapes critically influence the pathogenesis of various human diseases. This understanding has laid a robust theoretical groundwork for developing drugs that target epigenetics-modifying enzymes in pathological conditions. Over the past two decades, a growing array of small molecule drugs targeting epigenetic enzymes such as DNA methyltransferase, histone deacetylase, isocitrate dehydrogenase, and enhancer of zeste homolog 2, have been thoroughly investigated and implemented as therapeutic options, particularly in oncology. Additionally, numerous epigenetics-targeted drugs are undergoing clinical trials, offering promising prospects for clinical benefits. This review delineates the roles of epigenetics in physiological and pathological contexts and underscores pioneering studies on the discovery and clinical implementation of epigenetics-targeted drugs. These include inhibitors, agonists, degraders, and multitarget agents, aiming to identify practical challenges and promising avenues for future research. Ultimately, this review aims to deepen the understanding of epigenetics-oriented therapeutic strategies and their further application in clinical settings.

Resistance to Tyrosine Kinase Inhibitors in Hepatocellular Carcinoma (HCC): Clinical Implications and Potential Strategies to Overcome the Resistance

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, and the development of effective treatment strategies remains a significant challenge in the management of advanced HCC patients. The emergence of tyrosine kinase inhibitors (TKIs) has been a significant advancement in the treatment of HCC, as these targeted therapies have shown promise in prolonging the survival of patients with advanced disease. Although immunotherapy is currently considered as the first line of treatment for advanced HCC patients, many such patients do not meet the clinical criteria to be eligible for immunotherapy, and in many parts of the world there is still lack of accessibility to immunotherapy. As such, TKIs still serve as the first line of treatment and play a major role in the treatment repertoire for advanced HCC patients. However, the development of resistance to these agents is a major obstacle that must be overcome. In this review, we explore the underlying mechanisms of resistance to TKIs in HCC, the clinical implications of this resistance, and the potential strategies to overcome or prevent the emergence of resistance.

Adenosine Receptor 3 in Liver Cancer: Expression Variability, Epigenetic Modulation, and Enhanced Histone Deacetylase Inhibitor Effects

Background and Aims

Primary liver cancer, including hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), has low response rates to existing treatments, highlighting the urgent need for novel treatment options. Adenosine A3 receptor (ADORA3) signaling has emerged as a potential target. Namodenoson, an ADORA3 agonist, has shown promise in early clinical trials for HCC. However, further data are required to clarify ADORA3 expression patterns in liver cancer, mechanisms of action, and the potential for combination therapies to inform patient selection for future clinical trials.

Methods

Patient-derived tissue microarrays and RNA-sequencing were employed to investigate ADORA3 expression. Cellular responses to ADORA3 stimulation and combination treatments were studied in HCC and CCA cell lines and patient-derived organoids (PDOs). Genome-wide RNA-Seq analysis, mRNA analysis, and DigiWest protein profiling were performed.

Results

Tissue microarray analysis revealed higher ADORA3 expression in nonmalignant samples and a subset of tumors with weak or absent ADORA3 expression. This was supported by RNA sequencing data from The Cancer Genome Atlas and needle biopsy samples. Cell lines and PDOs exhibited antiproliferative effects with the ADORA3 agonist Namodenoson, confirmed by receptor dependency tests with specific antagonists and siRNA experiments. Genome-wide RNA-Seq analysis suggested chromatin remodeling events after ADORA3 stimulation. mRNA expression and DigiWest profiling identified downregulation of histone deacetylases and histone H3 modifications. Combination treatments with different ADORA3 agonists and histone deacetylase inhibitors significantly enhanced antiproliferative effects in almost all selected combinations, supported by investigations in PDOs.

Conclusion

ADORA3 expression varies considerably in HCC or CCA, ranging from high to absent receptor detection. This observation might help to identify patients for clinical studies. Additionally, Namodenoson's epigenetic modulating activity suggests epigenetic drugs as promising candidates for combination treatment.

Progresses and Pitfalls of Epigenetics in Solid Tumors Clinical Trials

Epigenetic dysregulation has long been recognized as a significant contributor to tumorigenesis and tumor maintenance, impacting all recognized cancer hallmarks. Although some epigenetic drugs have received regulatory approval for certain hematological malignancies, their efficacy in treating solid tumors has so far been largely disappointing. However, recent advancements in developing new compounds and a deeper understanding of cancer biology have led to success in specific solid tumor subtypes through precision medicine approaches. Moreover, epigenetic drugs may play a crucial role in synergizing with other anticancer treatments, enhancing the sensitivity of cancer cells to various anticancer therapies, including chemotherapy, radiation therapy, hormone therapy, targeted therapy, and immunotherapy. In this review, we critically evaluate the evolution of epigenetic drugs, tracing their development from initial use as monotherapies to their current application in combination therapies. We explore the preclinical rationale, completed clinical studies, and ongoing clinical trials. Finally, we discuss trial design strategies and drug scheduling to optimize the development of possible combination therapies.

Mitoepigenetics pathways and natural compounds: a dual approach to combatting hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading liver cancer that significantly impacts global life expectancy and remains challenging to treat due to often late diagnoses. Despite advances in treatment, the prognosis is still poor, especially in advanced stages. Studies have pointed out that investigations into the molecular mechanisms underlying HCC, including mitochondrial dysfunction and epigenetic regulators, are potentially important targets for diagnosis and therapy. Mitoepigenetics, or the epigenetic modifications of mitochondrial DNA, have drawn wide attention for their role in HCC progression. Besides, molecular biomarkers such as mitochondrial DNA alterations and non-coding RNAs showed early diagnosis and prognosis potential. Additionally, natural compounds like alkaloids, resveratrol, curcumin, and flavonoids show promise in HCC show promise in modulating mitochondrial and epigenetic pathways involved in cancer-related processes. This review discusses how mitochondrial dysfunction and epigenetic modifications, especially mitoepigenetics, influence HCC and delves into the potential of natural products as new adjuvant treatments against HCC.

Heterocycles-Containing HDAC Inhibitors Active in Cancer: An Overview of the Last Fifteen Years

Cancer is one of the primary causes of mortality worldwide. Despite nowadays are numerous therapeutic treatments to fight tumor progression, it is still challenging to completely overcome it. It is known that Histone Deacetylases (HDACs), epigenetic enzymes that remove acetyl groups from lysines on histone's tails, are overexpressed in various types of cancer, and their inhibition represents a valid therapeutic strategy. To date, some HDAC inhibitors have achieved FDA approval. Nevertheless, several other potential drug candidates have been developed. This review aims primarily to be comprehensive of the studies done so far regarding HDAC inhibitors bearing heterocyclic rings since their therapeutic potential is well known and has gained increasing interest in recent years. Hence, inserting heterocyclic moieties in the HDAC-inhibiting scaffold can be a valuable strategy to provide potent and/or selective compounds. Here, in addition to summarizing the properties of novel heterocyclic HDAC inhibiting compounds, we also provide ideas for developing new, more potent, and selective compounds for treating cancer.

Targeting of human cancer stem cells predicts efficacy and toxicity of FDA-approved oncology drugs

Cancer remains the leading cause of death worldwide with approved oncology drugs continuing to have heterogenous patient responses and accompanied adverse effects (AEs) that limits effectiveness. Here, we examined >100 FDA-approved oncology drugs in the context of stemness using a surrogate model of transformed human pluripotent cancer stem cells (CSCs) vs. healthy stem cells (hSCs) capable of distinguishing abnormal self-renewal and differentiation. Although a proportion of these drugs had no effects (inactive), a larger portion affected CSCs (active), and a unique subset preferentially affected CSCs over hSCs (selective). Single cell gene expression and protein profiling of each drug's FDA recognized target provided a molecular correlation of responses in CSCs vs. hSCs. Uniquely, drugs selective for CSCs demonstrated clinical efficacy, measured by overall survival, and reduced AEs. Our findings reveal that while unintentional, half of anticancer drugs are active against CSCs and associated with improved clinical outcomes. Based on these findings, we suggest ability to target CSC targeting should be included as a property of early onco-therapeutic development.

Heat shock transcription factor 1 facilitates liver cancer progression by driving super-enhancer-mediated transcription of MYCN

BACKGROUND

Heat shock transcription factors (HSFs) play crucial roles in the development of malignancies. However, the specific roles of HSFs in hepatocellular carcinoma (HCC) have yet to be fully elucidated.

AIMS

To explore the involvement of the HSF family, particularly HSF1, in the progression and prognosis of HCC.

MATERIALS & METHODS

We conducted a thorough analysis of HSF expression and copy number variations across various cancer datasets. Specifically focusing on HSF1, we examined its expression levels and prognostic implications in HCC. In vitro and in vivo experiments were carried out to evaluate the impact of HSF1 on liver cancer cell proliferation. Additionally, we utilized CUT&Tag, H3K27 acetylation enrichment, and RNA sequencing (RNA-seq) to investigate the super-enhancer (SE) regulatory landscapes of HSF1 in liver cancer cell lines.

RESULTS

HSF1 expression is elevated in HCC and is linked to poor prognosis in several datasets. HSF1 stimulates liver cancer cell proliferation both in vitro and in vivo, partly through modulation of H3K27ac levels, influencing enhancer distribution. Mechanistically, our findings demonstrate that HSF1 transcriptionally activates MYCN expression by binding to its promoter and SE elements, thereby promoting liver cancer cell proliferation. Moreover, increased MYCN expression was detected in HCC tumors and correlated with unfavorable patient outcomes.

DISCUSSION

Our study sheds light on previously unexplored aspects of HSF1 biology, identifying it as a transcription factor capable of shaping the epigenetic landscape in the context of HCC. Given HSF1's potential as an epigenetic regulator, targeting the HSF1-MYCN axis could open up new therapeutic possibilities for HCC treatment.

CONCLUSION

The HSF1-MYCN axis constitutes a transcription-dependent regulatory mechanism that may function as both a prognostic indicator and a promising therapeutic target in liver cancer. Further exploration of this axis could yield valuable insights into novel treatment strategies for HCC.

Inflammatory Response in the Pathogenesis and Treatment of Hepatocellular Carcinoma: A Double-Edged Weapon

Hepatocellular carcinoma (HCC) is the most frequent among primary liver tumors (90%) and one of the main causes of cancer-related death. It develops usually in a chronically inflamed environment, ranging from compensatory parenchymal regeneration to fibrosis and cirrhosis: carcinogenesis can potentially happen in each of these stages. Inflammation determined by chronic viral infection (hepatitis B, hepatitis C, and hepatitis delta viruses) represents an important risk factor for HCC etiology through both viral direct damage and immune-related mechanisms. The deregulation of the physiological liver immunological network determined by viral infection can lead to carcinogenesis. The recent introduction of immunotherapy as the gold-standard first-line treatment for HCC highlights the role of the immune system and inflammation as a double-edged weapon in both HCC carcinogenesis and treatment. In this review we highlight how the inflammation is the key for the hepatocarcinogenesis in viral, alcohol and metabolic liver diseases.

The efficacy and safety of different systemic combination therapies on advanced hepatocellular carcinoma: a systematic review and meta-analysis

Background and aims

Systemic combinations have recently brought significant therapeutic benefits for advanced hepatocellular carcinoma (aHCC). To design the most effective combination regimens, a systematic review (PROSPERO ID: CRD42022321949) was conducted to evaluate the efficacy and safety of systemic combinations on aHCC.

Methods

We retrieved all the studies from PubMed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and China National Knowledge Infrastructure (CNKI) using the Medical Subject Headings (MeSH) terms until December 21, 2022. The effect indicators (hazard ratio [HR], relative risk [RR], and median) were pooled by a fixed- or random-effects model. A subgroup analysis was conducted according to types and specific therapies.

Results

In total, 88 eligible studies were selected from 7249 potential records. Each kind of combination treatment (chemotherapy plus chemotherapy, targeted plus immune checkpoint inhibitor (ICI) therapy, targeted plus chemotherapy, and targeted plus targeted therapy) had a better objective response rate (ORR) in patients with aHCC, compared to the monotherapy mostly with sorafenib (RR: 1.57 [1.44-1.71]; I 2 = 30%). Of those, targeted plus ICI therapy showed better therapeutic efficiency in overall survival (median: 15.02 [12.67-17.38]), progression-free survival (median: 7.08 [6.42-7.74]), and ORR (RR: 1.81 [1.55-2.13]), compared to the monotherapy. Specifically, Atezo plus Beva showed all those benefits. Our pooled result showed all the combinations had increased ≥3 Grade treatment-related adverse events (TrAEs), with an RR of 1.25 [95% CI: 1.15-1.36], compared to the monotherapy.

Conclusion

The systemic combinations, especially targeted plus ICI therapy, including Atezo plus Beva, significantly improve clinical outcomes but increase side effects in patients with aHCC. Future trials should concentrate on improvement in therapeutic efficiency and reduction of toxicity of targeted plus ICI therapy.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022321949.

Post-translational modifications of histones: Mechanisms, biological functions, and therapeutic targets

Histones are DNA-binding basic proteins found in chromosomes. After the histone translation, its amino tail undergoes various modifications, such as methylation, acetylation, phosphorylation, ubiquitination, malonylation, propionylation, butyrylation, crotonylation, and lactylation, which together constitute the "histone code." The relationship between their combination and biological function can be used as an important epigenetic marker. Methylation and demethylation of the same histone residue, acetylation and deacetylation, phosphorylation and dephosphorylation, and even methylation and acetylation between different histone residues cooperate or antagonize with each other, forming a complex network. Histone-modifying enzymes, which cause numerous histone codes, have become a hot topic in the research on cancer therapeutic targets. Therefore, a thorough understanding of the role of histone post-translational modifications (PTMs) in cell life activities is very important for preventing and treating human diseases. In this review, several most thoroughly studied and newly discovered histone PTMs are introduced. Furthermore, we focus on the histone-modifying enzymes with carcinogenic potential, their abnormal modification sites in various tumors, and multiple essential molecular regulation mechanism. Finally, we summarize the missing areas of the current research and point out the direction of future research. We hope to provide a comprehensive understanding and promote further research in this field.

HDAC inhibitors enhance the anti-tumor effect of immunotherapies in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the most common liver malignancy with a poor prognosis and increasing incidence, remains a serious health problem worldwide. Immunotherapy has been described as one of the ideal ways to treat HCC and is transforming patient management. However, the occurrence of immunotherapy resistance still prevents some patients from benefiting from current immunotherapies. Recent studies have shown that histone deacetylase inhibitors (HDACis) can enhance the efficacy of immunotherapy in a variety of tumors, including HCC. In this review, we present current knowledge and recent advances in immunotherapy-based and HDACi-based therapies for HCC. We highlight the fundamental dynamics of synergies between immunotherapies and HDACis, further detailing current efforts to translate this knowledge into clinical benefits. In addition, we explored the possibility of nano-based drug delivery system (NDDS) as a novel strategy to enhance HCC treatment.

Potential Immunotherapy Targets for Liver-Directed Therapies, and the Current Scope of Immunotherapeutics for Liver-Related Malignancies

Liver cancer, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma, is increasing in incidence and mortality across the globe. An improved understanding of the complex tumor microenvironment has opened many therapeutic doors and led to the development of novel pharmaceuticals targeting cellular signaling pathways or immune checkpoints. These interventions have significantly improved tumor control rates and patient outcomes, both in clinical trials and in real-world practice. Interventional radiologists play an important role in the multidisciplinary team given their expertise in minimally invasive locoregional therapy, as the bulk of these tumors are usually in the liver. The aim of this review is to highlight the immunological therapeutic targets for primary liver cancers, the available immune-based approaches, and the contributions that interventional radiology can provide in the care of these patients.

Multifaceted Influence of Histone Deacetylases on DNA Damage Repair: Implications for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancers and a leading cause of cancer-related mortality worldwide, but its pathogenesis remains largely unknown. Nevertheless, genomic instability has been recognized as one of the facilitating characteristics of cancer hallmarks that expedites the acquisition of genetic diversity. Genomic instability is associated with a greater tendency to accumulate DNA damage and tumor-specific DNA repair defects, which gives rise to gene mutations and chromosomal damage and causes oncogenic transformation and tumor progression. Histone deacetylases (HDACs) have been shown to impair a variety of cellular processes of genome stability, including the regulation of DNA damage and repair, reactive oxygen species generation and elimination, and progression to mitosis. In this review, we provide an overview of the role of HDAC in the different aspects of DNA repair and genome instability in HCC as well as the current progress on the development of HDAC-specific inhibitors as new cancer therapies.

Epigenetic Regulations in Autoimmunity and Cancer: from Basic Science to Translational Medicine

Epigenetics, as a discipline that aims to explain the differential expression of phenotypes arising from the same gene sequence and the heritability of epigenetic expression, has received much attention in medicine. Epigenetic mechanisms are constantly being discovered, including DNA methylation, histone modifications, noncoding RNAs and m6A. The immune system mainly achieves an immune response through the differentiation and functional expression of immune cells, in which epigenetic modification will have an important impact. Because of immune infiltration in the tumor microenvironment, immunotherapy has become a research hotspot in tumor therapy. Epigenetics plays an important role in autoimmune diseases and cancers through immunology. An increasing number of drugs targeting epigenetic mechanisms, such as DNA methyltransferase inhibitors, histone deacetylase inhibitors, and drug combinations, are being evaluated in clinical trials for the treatment of various cancers (including leukemia and osteosarcoma) and autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis). This review summarizes the progress of epigenetic regulation for cancers and autoimmune diseases to date, shedding light on potential therapeutic strategies.

Recent advances in epigenetic anticancer therapeutics and future perspectives

Tumor development is frequently accompanied by abnormal expression of multiple genomic genes, which can be broadly viewed as decreased expression of tumor suppressor genes and upregulated expression of oncogenes. In this process, epigenetic regulation plays an essential role in the regulation of gene expression without alteration of DNA or RNA sequence, including DNA methylation, RNA methylation, histone modifications and non-coding RNAs. Therefore, drugs developed for the above epigenetic modulation have entered clinical use or preclinical and clinical research stages, contributing to the development of antitumor drugs greatly. Despite the efficacy of epigenetic drugs in hematologic caners, their therapeutic effects in solid tumors have been less favorable. A growing body of research suggests that epigenetic drugs can be applied in combination with other therapies to increase efficacy and overcome tumor resistance. In this review, the progress of epigenetics in tumor progression and oncology drug development is systematically summarized, as well as its synergy with other oncology therapies. The future directions of epigenetic drug development are described in detail.

Epigenetics in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and has a high fatality rate. Genetic and epigenetic aberrations are commonly observed in HCC. The epigenetic processes include chromatin remodelling, histone alterations, DNA methylation, and noncoding RNA (ncRNA) expression and are connected with the progression and metastasis of HCC. Due to their potential reversibility, these epigenetic alterations are widely targeted for the development of biomarkers. In-depth understanding of the epigenetics of HCC is critical for developing rational clinical strategies that can provide a meaningful improvement in overall survival and prediction of therapeutic outcomes. In this article, we have summarised the epigenetic modifications involved in HCC progression and highlighted the potential biomarkers for diagnosis and drug development.

The role of protein acetylation in carcinogenesis and targeted drug discovery

Protein acetylation is a reversible post-translational modification, and is involved in many biological processes in cells, such as transcriptional regulation, DNA damage repair, and energy metabolism, which is an important molecular event and is associated with a wide range of diseases such as cancers. Protein acetylation is dynamically regulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs) in homeostasis. The abnormal acetylation level might lead to the occurrence and deterioration of a cancer, and is closely related to various pathophysiological characteristics of a cancer, such as malignant phenotypes, and promotes cancer cells to adapt to tumor microenvironment. Therapeutic modalities targeting protein acetylation are a potential therapeutic strategy. This article discussed the roles of protein acetylation in tumor pathology and therapeutic drugs targeting protein acetylation, which offers the contributions of protein acetylation in clarification of carcinogenesis, and discovery of therapeutic drugs for cancers, and lays the foundation for precision medicine in oncology.

Targeted Therapy for Hepatocellular Carcinoma: Old and New Opportunities

Hepatocellular carcinoma (HCC) is the most frequent primitive cancer of the liver, accounting for 90% of all recorded cases. HCC is the third most common cause of cancer-related death, with a 5-year survival rate of just 3%. In the advanced stages, systemic treatments allow doctors to obtain clinical benefits, although the prognosis remains very poor. In the past few decades, new molecular targeted therapies against receptor tyrosine kinases have been developed and clinically evaluated. Sorafenib was the first oral tyrosine kinase inhibitor (TKI) approved for the treatment of advanced HCC in 2007. Subsequently, other TKIs, including Cabozantinib, Regorafenib, Lenvatinib, and vascular endothelial growth factor receptor (VEGFR) inhibitors such as Ramucirumab and VEGF inhibitors such as Bevacizumab have been approved as first- or second-line treatments. More recently, the combination of immune checkpoint inhibitors and VEGF inhibitors (Atezolizumab plus Bevacizumab) have been analyzed and approved for the treatment of advanced HCC. On the basis of the poor prognoses and the meager benefits deriving from the available systemic therapies, research into new treatments is extremely necessary. In this review, we focus on the available systemic therapies for advanced HCC, with a look toward the future.

Ursolic acid enhances the antitumor effects of sorafenib associated with Mcl-1-related apoptosis and SLC7A11-dependent ferroptosis in human cancer

As a broad-spectrum oral small molecule inhibitor targeting multikinase, sorafenib is currently approved for the clinical treatment of several types of cancer as a single agent. A considerable number of clinical trial results have indicated that combination therapies involving sorafenib have been shown to improve treatment efficacy and may lead to novel therapeutic applications. Ursolic acid (UA), a natural pentacyclic triterpene compound extracted from a great variety of traditional medicinal plants and most fruits and vegetables, exhibits a wide range of therapeutic potential, including against cancer, diabetes, brain disease, liver disease, cardiovascular diseases, and sarcopenia. In the present study, we investigated the antitumor effects of sorafenib in combination with ursolic acid and found that the two agents displayed significant synergistic antitumor activity in in vitro and in vivo tumor xenograft models. Sorafenib/UA induced selective apoptotic death and ferroptosis in various cancer cells by evoking a dramatic accumulation of intracellular lipid reactive oxygen species (ROS). Mechanistically, the combination treatment promoted Mcl-1 degradation, which regulates apoptosis. However, decreasing the protein level of SLC7A11 plays a critical role in sorafenib/UA-induced cell ferroptosis. Therefore, these results suggest that the synergistic antitumor effects of sorafenib combined with ursolic acid may involve the induction of Mcl-1-related apoptosis and SLC7A11-dependent ferroptosis. Our findings may offer a novel effective therapeutic strategy for tumor treatment.

In-depth Profiling and Quantification of the Lysine Acetylome in Hepatocellular Carcinoma with a Trapped Ion Mobility Mass Spectrometer

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death worldwide with limited therapeutic options. Comprehensive investigation of protein posttranslational modifications in HCC is still limited. Lysine acetylation is one of the most common types of posttranslational modification involved in many cellular processes and plays crucial roles in the regulation of cancer. In this study, we analyzed the proteome and K-acetylome in eight pairs of HCC tumors and normal adjacent tissues using a timsTOF Pro instrument. As a result, we identified 9219 K-acetylation sites in 2625 proteins, of which 1003 sites exhibited differential acetylation levels between tumors and normal adjacent tissues. Interestingly, many novel tumor-specific K-acetylation sites were characterized, for example, filamin A (K865), filamin B (K697), and cofilin (K19), suggesting altered activities of these cytoskeleton-modulating molecules, which may contribute to tumor metastasis. In addition, we observed an overall suppression of protein K-acetylation in HCC tumors, especially for enzymes from various metabolic pathways, for example, glycolysis, tricarboxylic acid cycle, and fatty acid metabolism. Moreover, the expression of deacetylase sirtuin 2 (SIRT2) was upregulated in HCC tumors, and its role of deacetylation in HCC cells was further explored by examining the impact of SIRT2 overexpression on the proteome and K-acetylome in Huh7 HCC cells. SIRT2 overexpression reduced K-acetylation of proteins involved in a wide range of cellular processes, including energy metabolism. Furthermore, cellular assays showed that overexpression of SIRT2 in HCC cells inhibited both glycolysis and oxidative phosphorylation. Taken together, our findings provide valuable information to better understand the roles of K-acetylation in HCC and to treat this disease by correcting the aberrant acetylation patterns.

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K-acetylation was generally reduced in HCC, especially in metabolic enzymes.

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Deacetylase SIRT2 was upregulated in HCC tumors.

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SIRT2 overexpression induced broad alteration of protein K-acetylation.

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SIRT2 overexpression inhibited glycolysis and oxidative phosphorylation.

Chimeric HDAC and the cytoskeleton inhibitor broxbam as a novel therapeutic strategy for liver cancer

Broxbam, also known as N-hydroxy-4-{1-methoxy-4-[4′-(3′-bromo-4′,5′-dimethoxyphenyl)-oxazol-5′-yl]-2-phenoxy} butanamide, is a novel chimeric inhibitor that contains two distinct pharmacophores in its molecular structure. It has been previously demonstrated to inhibit the activity of histone deacetylases (HDAC) and tubulin polymerisation, two critical components required for cancer growth and survival. In the present study, the potential suitability of broxbam for the treatment of liver cancer was investigated. The effects of broxbam on cell proliferation and apoptosis, in addition to the under-lying molecular mechanism of action, were first investigated in primary liver cancer cell lines Huh7, HepG2, TFK1 and EGI1. Real-time proliferation measurements made using the iCEL-Ligence system and viable cell number counting following crystal violet staining) revealed that broxbam time- and dose-dependently reduced the proliferation of liver cancer cell lines with IC₅₀ values <1 µM. In addition, a significant inhibition of the growth of hepatoblastoma microtumours on the chorioallantoic membranes (CAM) of fertilised chicken eggs by broxbam was observed according to results from the CAM assay, suggesting antineoplastic potency in vivo. Broxbam also exerted apoptotic effects through p53- and mitochondria-driven caspase-3 activation in Huh7 and HepG2 cells according to data from western blotting (p53 and phosphorylated p53), mitochondrial membrane potential measurements (JC-1 assay) and fluorometric capsase-3 measurements. Notably, no contribution of unspecific cytotoxic effects mediated by broxbam were observed from LDH-release measurements. HDAC1, -2, -4 and -6 expression was measured by western blotting and the HDAC inhibitory potency of broxbam was next evaluated using subtype-specific HDAC enzymatic assays, which revealed a largely pan-HDAC inhibitory activity with the most potent inhibition observed on HDAC6. Silencing HDAC6 expression in Huh7 cells led to a drop in the expression of the proliferation markers Ki-67 and E2F3, suggesting that HDAC6 inhibition by broxbam may serve a predomi-nant role in their antiproliferative effects on liver cancer cells. Immunofluorescence staining of cytoskeletal proteins (α-tubulin & actin) of broxbam-treated HepG2 cells revealed a pronounced inhibition of tubulin polymerisation, which was accompanied by reduced cell migration as determined by wound healing scratch assays. Finally, data from zebrafish angiogenesis assays revealed marked antiangiogenic effects of broxbam in vivo, as shown by the suppression of subintestinal vein growth in zebrafish embryos. To conclude, the pleiotropic anticancer activities of this novel chimeric HDAC- and tubulin inhibitor broxbam suggest that this compound is a promising candidate for liver cancer treatment, which warrants further pre-clinical and clinical evaluation.

Neutrophils as potential therapeutic targets in hepatocellular carcinoma

The success of atezolizumab plus bevacizumab treatment contributed to a shift in systemic therapies for hepatocellular carcinoma (HCC) towards combinations that include cancer immunotherapeutic agents. Thus far, the principal focus of cancer immunotherapy has been on interrupting immune checkpoints that suppress antitumour lymphocytes. As well as lymphocytes, the HCC environment includes numerous other immune cell types, among which neutrophils are emerging as an important contributor to the pathogenesis of HCC. A growing body of evidence supports neutrophils as key mediators of the immunosuppressive environment in which some cancers develop, as well as drivers of tumour progression. If neutrophils have a similar role in HCC, approaches that target or manipulate neutrophils might have therapeutic benefits, potentially including sensitization of tumours to conventional immunotherapy. Several neutrophil-directed therapies for patients with HCC (and other cancers) are now entering clinical trials. This Review outlines the evidence in support of neutrophils as drivers of HCC and details their mechanistic roles in development, progression and metastasis, highlighting the reasons that neutrophils are well worth investigating despite the challenges associated with studying them. Neutrophil-modulating anticancer therapies entering clinical trials are also summarized.

Epigenetic remodelling in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer, being the sixth most commonly diagnosed cancer and the fourth leading cause of cancer-related death. As other heterogeneous solid tumours, HCC results from a unique synergistic combination of genetic alterations mixed with epigenetic modifications.In HCC the patterns and frequencies of somatic variations change depending on the nearby chromatin. On the other hand, epigenetic alterations often induce genomic instability prone to mutations. Epigenetics refers to heritable states of gene expression without alteration to the DNA sequence itself and, unlike genetic changes, the epigenetic modifications are reversible and affect gene expression more extensively than genetic changes. Thus, studies of epigenetic regulation and the involved molecular machinery are greatly contributing to the understanding of the mechanisms that underline HCC onset and heterogeneity. Moreover, this knowledge may help to identify biomarkers for HCC diagnosis and prognosis, as well as future new targets for more efficacious therapeutic approaches.In this comprehensive review we will discuss the state-of-the-art knowledge about the epigenetic landscape in hepatocarcinogenesis, including evidence on the diagnostic and prognostic role of non-coding RNAs, modifications occurring at the chromatin level, and their role in the era of precision medicine.Apart from other better-known risk factors that predispose to the development of HCC, characterization of the epigenetic remodelling that occurs during hepatocarcinogenesis could open the way to the identification of personalized biomarkers. It may also enable a more accurate diagnosis and stratification of patients, and the discovery of new targets for more efficient therapeutic approaches.

Systemic Therapy for Hepatocellular Carcinoma: Current Updates and Outlook

Hepatocellular carcinoma (HCC) has emerged the culprit of cancer-related mortality worldwide with its dismal prognosis climbing. In recent years, ground-breaking progress has been made in systemic therapy for HCC. Targeted therapy based on specific signaling molecules, including sorafenib, lenvatinib, regorafenib, cabozantinib, and ramucirumab, has been widely used for advanced HCC (aHCC). Immunotherapies such as pembrolizumab and nivolumab greatly improve the survival of aHCC patients. More recently, synergistic combination therapy has boosted first-line (atezolizumab in combination with bevacizumab) and second-line (ipilimumab in combination with nivolumab) therapeutic modalities for aHCC. This review aims to summarize recent updates of systemic therapy relying on the biological mechanisms of HCC, particularly highlighting the approved agents for aHCC. Adjuvant and neoadjuvant therapy, as well as a combination with locoregional therapies (LRTs), are also discussed. Additionally, we describe the promising effect of traditional Chinese medicine (TCM) as systemic therapy on HCC. In this setting, the challenges and future directions of systemic therapy for HCC are also explored.

Implications of Stemness Features in 1059 Hepatocellular Carcinoma Patients from Five Cohorts: Prognosis, Treatment Response, and Identification of Potential Compounds

Cancer stemness has been reported to drive hepatocellular carcinoma (HCC) tumorigenesis and treatment resistance. In this study, five HCC cohorts with 1059 patients were collected to calculate transcriptional stemness indexes (mRNAsi) by the one-class logistic regression machine learning algorithm. In the TCGA-LIHC cohort, we found mRNAsi was an independent prognostic factor, and 626 mRNAsi-related genes were identified by Spearman correlation analysis. The HCC stemness risk model (HSRM) was trained in the TCGA-LIHC cohort and significantly discriminated overall survival in four independent cohorts. HSRM was also significantly associated with transarterial chemoembolization treatment response and rapid tumor growth in HCC patients. Consensus clustering was conducted based on mRNAsi-related genes to divide 1059 patients into two stemness subtypes. On gene set variation analysis, samples of subtype I were found enriched with pathways such as DNA replication and cell cycle, while several liver-specific metabolic pathways were inhibited in these samples. Somatic mutation analysis revealed more frequent mutations of TP53 and RB1 in the subtype I samples. In silico analysis suggested topoisomerase, cyclin-dependent kinase, and histone deacetylase as potential targets to inhibit HCC stemness. In vitro assay showed two predicted compounds, Aminopurvalanol-a and NCH-51, effectively suppressed oncosphere formation and impaired viability of HCC cell lines, which may shed new light on HCC treatment.

Toward a postbiotic era of microbiome science: Opportunities to advance immunotherapies for hepatocellular carcinoma

The microbiome has revolutionized the field of cancer immunology and checkpoint therapeutics for gastrointestinal malignancies. Combating hepatocellular carcinoma (HCC) by immune checkpoint blockade (ICB) is a unique challenge due in part to chronic complications that arise from local and systemic metabolic dysfunctions. Gut microbial metabolites modulate key immunological processes that influence liver cancer susceptibility and resistance to ICB. This review discusses recent progresses in linking microbiota functions to HCC tumor immunity and highlights their therapeutic potential.

Metabolism-Associated Epigenetic and Immunoepigenetic Reprogramming in Liver Cancer

Metabolic reprogramming and epigenetic changes have been characterized as hallmarks of liver cancer. Independently of etiology, oncogenic pathways as well as the availability of different energetic substrates critically influence cellular metabolism, and the resulting perturbations often cause aberrant epigenetic alterations, not only in cancer cells but also in the hepatic tumor microenvironment. Metabolic intermediates serve as crucial substrates for various epigenetic modulations, from post-translational modification of histones to DNA methylation. In turn, epigenetic changes can alter the expression of metabolic genes supporting on the one hand, the increased energetic demand of cancer cells and, on the other hand, influence the activity of tumor-associated immune cell populations. In this review, we will illustrate the most recent findings about metabolic reprogramming in liver cancer. We will focus on the metabolic changes characterizing the tumor microenvironment and on how these alterations impact on epigenetic mechanisms involved in the malignant progression. Furthermore, we will report our current knowledge about the influence of cancer-specific metabolites on epigenetic reprogramming of immune cells and we will highlight how this favors a tumor-permissive immune environment. Finally, we will review the current strategies to target metabolic and epigenetic pathways and their therapeutic potential in liver cancer, alone or in combinatorial approaches.

HCC and Molecular Targeting Therapies: Back to the Future

Hepatocellular carcinoma (HCC) is one of the leading causes of death from cancer in the world. Recently, the effectiveness of new antiviral therapies and the HBV vaccine have reduced HCC’s incidence, while non-alcoholic steato-hepatitis is an emerging risk factor. This review focuses on antiangiogenic molecules and immune checkpoint inhibitors approved for HCC treatment and possible future approaches. Sorafenib was the first drug approved for the treatment of advanced HCC (aHCC) and it has been shown to increase survival by a few months. Lenvatinib, a multikinase inhibitor, has shown non-inferiority in survival compared with sorafenib and an improvement in progression-free survival (PFS). The combination of atezolizumab (an anti-PDL1 antibody) and bevacizumab (an anti-VEGF antibody) was the first drug combination approved for HCC, demonstrating improved survival compared with sorafenib (19.2 vs. 13.4 months). As a second line of therapy, three regimens (regorafenib, cabozantinib, and ramucirumab) have been approved for the treatment of aHCC after progression on sorafenib according to guidelines. Furthermore, nivolumab, pembrolizumab, and nivolumab plus ipilimumab have been approved by the FDA (2017, 2018, and 2020, respectively). Finally, immune target therapy, cancer vaccines, and epigenetic drugs represent three new possible weapons for the treatment of HCC.

Epigenetic mechanisms of liver tumor resistance to immunotherapy

Hepatocellular carcinoma (HCC) is the most common primary liver tumor, which stands fourth in rank of cancer-related deaths worldwide. The incidence of HCC is constantly increasing in correlation with the epidemic in diabetes and obesity, arguing for an urgent need for new treatments for this lethal cancer refractory to conventional treatments. HCC is the paradigm of inflammation-associated cancer, since more than 80% of HCC emerge consecutively to cirrhosis associated with a vast remodeling of liver microenvironment. In the recent decade, immunomodulatory drugs have been developed and have given impressive results in melanoma and later in several other cancers. In the present review, we will discuss the recent advancements concerning the use of immunotherapies in HCC, in particular those targeting immune checkpoints, used alone or in combination with other anti-cancers agents. We will address why these drugs demonstrate unsatisfactory results in a high proportion of liver cancers and the mechanisms of resistance developed by HCC to evade immune response with a focus on the epigenetic-related mechanisms.

Glutathione Peroxidase 8 Suppression by Histone Deacetylase Inhibitors Enhances Endoplasmic Reticulum Stress and Cell Death by Oxidative Stress in Hepatocellular Carcinoma Cells

Histone deacetylase inhibitors (HDACi) are emerging as anti-hepatocellular carcinoma (HCC) agents. However, the molecular mechanisms underlying HDACi-induced sensitization to oxidative stress and cell death of HCC remain elusive. We hypothesized that HDACi reduces the anti-oxidative stress capacity of HCC, rendering it more susceptible to oxidative stress and cell death. Change in the transcriptome of HCC was analyzed by RNA-seq and validated using real-time quantitative polymerase chain reaction (qPCR) and Western blot. Cell death of HCC was analyzed by fluorescence-activated cell sorting (FACS). Protein localization and binding on the target gene promoters were investigated by immunofluorescence (IF) and chromatin immunoprecipitation (ChIP), respectively. Glutathione peroxidase 8 (GPX8) was highly down-regulated in HCC upon oxidative stress and HDACi co-treatment. Oxidative stress and HDACi enhanced the expression and transcriptional activities of ER-stress-related genes. N-acetyl-cysteine (NAC) supplementation reversed the oxidative stress and HDACi-induced apoptosis in HCC. HDACi significantly enhanced the effect of ER stressors on HCC cell death. GPX8 overexpression reversed the activation of ER stress signaling and apoptosis induced by oxidative stress and HDACi. In conclusion, HDACi suppresses the expression of GPX8, which sensitizes HCC to ER stress and apoptosis by oxidative stress.

DNA Methylation of TGFβ Target Genes: Epigenetic Control of TGFβ Functional Duality in Liver Cancer

Transforming growth factor beta (TGFβ) plays a key role in liver carcinogenesis. However, its action is complex, since TGFβ exhibits tumor-suppressive or oncogenic properties, depending on the tumor stage. At an early stage TGFβ exhibits cytostatic features, but at a later stage it promotes cell growth and metastasis, as a potent inducer of epithelial to mesenchymal transition (EMT). Here, we evaluated DNA methylation as a possible molecular mechanism switching TGFβ activity toward tumor progression in hepatocellular carcinoma (HCC). We report that decitabine, a demethylating agent already used in the clinic for the treatment of several cancers, greatly impairs the transcriptional response of SNU449 HCC cells to TGFβ. Importantly, decitabine was shown to induce the expression of EMT-related transcription factors (e.g., SNAI1/2, ZEB1/2). We also report that the promoter of SNAI1 was hypomethylated in poor-prognosis human HCC, i.e., associated with high grade, high AFP level, metastasis and recurrence. Altogether, the data highlight an epigenetic control of several effectors of the TGFβ pathway in human HCC possibly involved in switching its action toward EMT and tumor progression. Thus, we conclude that epidrugs should be carefully evaluated for the treatment of HCC, as they may activate tumor promoting pathways.

Epigenetic Changes Affecting the Development of Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma is a life-threatening disease. Despite many efforts to understand the exact pathogenesis and the signaling pathways involved in its formation, treatment remains unsatisfactory. Currently, an important function in the development of neoplastic diseases and treatment effects is attributed to changes taking place at the epigenetic level. Epigenetic studies revealed modified methylation patterns in HCC, dysfunction of enzymes engaged in the DNA methylation process, the aberrant function of non-coding RNAs, and a set of histone modifications that influence gene expression. The aim of this review is to summarize the current knowledge on the role of epigenetics in the formation of hepatocellular carcinoma.

Abstract

Hepatocellular carcinoma (HCC) remains a serious oncologic issue with still a dismal prognosis. So far, no key molecular mechanism that underlies its pathogenesis has been identified. Recently, by specific molecular approaches, many genetic and epigenetic changes arising during HCC pathogenesis were detected. Epigenetic studies revealed modified methylation patterns in HCC tumors, dysfunction of enzymes engaged in the DNA methylation process, and a set of histone modifications that influence gene expression. HCC cells are also influenced by the disrupted function of non-coding RNAs, such as micro RNAs and long non-coding RNAs. Moreover, a role of liver cancer stem cells in HCC development is becoming evident. The reversibility of epigenetic changes offers the possibility of influencing them and regulating their undesirable effects. All these data can be used not only to identify new therapeutic targets but also to predict treatment response. This review focuses on epigenetic changes in hepatocellular carcinoma and their possible implications in HCC therapy.

Advances of Targeted Therapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the common and fatal malignancies, which is a significant global health problem. The clinical applicability of traditional surgery and other locoregional therapies is limited, and these therapeutic strategies are far from satisfactory in improving the outcomes of advanced HCC. In the past decade, targeted therapy had made a ground-breaking progress in advanced HCC. Those targeted therapies exert antitumor effects through specific signals, including anti-angiogenesis or cell cycle progression. As a standard systemic therapy option, it tremendously improves the survival of this devastating disease. Moreover, the combination of targeted therapy with immune checkpoint inhibitor (ICI) has demonstrated more potent anticancer effects and becomes the hot topic in clinical studies. The combining medications bring about a paradigm shift in the treatment of advanced HCC. In this review, we presented all approved targeted agents for advanced HCC with an emphasis on their clinical efficacy, summarized the advances of multi-target drugs in research for HCC and potential therapeutic targets for drug development. We also discussed the exciting results of the combination between targeted therapy and ICI.

DISMIR: Deep learning-based noninvasive cancer detection by integrating DNA sequence and methylation information of individual cell-free DNA reads

Detecting cancer signals in cell-free DNA (cfDNA) high-throughput sequencing data is emerging as a novel noninvasive cancer detection method. Due to the high cost of sequencing, it is crucial to make robust and precise predictions with low-depth cfDNA sequencing data. Here we propose a novel approach named DISMIR, which can provide ultrasensitive and robust cancer detection by integrating DNA sequence and methylation information in plasma cfDNA whole-genome bisulfite sequencing (WGBS) data. DISMIR introduces a new feature termed as ‘switching region’ to define cancer-specific differentially methylated regions, which can enrich the cancer-related signal at read-resolution. DISMIR applies a deep learning model to predict the source of every single read based on its DNA sequence and methylation state and then predicts the risk that the plasma donor is suffering from cancer. DISMIR exhibited high accuracy and robustness on hepatocellular carcinoma detection by plasma cfDNA WGBS data even at ultralow sequencing depths. Further analysis showed that DISMIR tends to be insensitive to alterations of single CpG sites’ methylation states, which suggests DISMIR could resist to technical noise of WGBS. All these results showed DISMIR with the potential to be a precise and robust method for low-cost early cancer detection.

Histone deacetylase inhibitor resminostat in combination with sorafenib counteracts platelet-mediated pro-tumoral effects in hepatocellular carcinoma

In hepatocellular carcinoma (HCC), blood platelets have been linked to tumor growth, epithelial-to-mesenchymal transition (EMT), extrahepatic metastasis and a limited therapeutic response to the multikinase inhibitor (MKi) sorafenib, the standard of care in advanced HCC for the last decade. Recent clinical data indicated an improved overall survival for sorafenib in combination with the HDAC inhibitor resminostat in a platelet count dependent manner. Here, the impact of platelets on the sorafenib and resminostat drug effects in HCC cells was explored. In contrast to sorafenib, resminostat triggered an anti-proliferative response in HCC cell lines independent of platelets. As previously described, platelets induced invasive capabilities of HCC cells, a prerequisite for extravasation and metastasis. Importantly, the resminostat/sorafenib drug combination, but not the individual drugs, effectively blocked platelet-induced HCC cell invasion. Exploration of the molecular mechanism revealed that the combined drug action led to a reduction of platelet-induced CD44 expression and to the deregulation of several other epithelial and mesenchymal genes, suggesting interference with cell invasion via EMT. In addition, the drug combination decreased phosphorylated ERK level, indicating inhibition of the mitogenic signaling pathway MEK/ERK. Taken together, the resminostat plus sorafenib combination counteracts platelet-mediated cancer promoting effects in HCC cells.

Host Epigenetic Alterations and Hepatitis B Virus-Associated Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most frequent primary malignancy of the liver and a leading cause of cancer-related deaths worldwide. Although much progress has been made in HCC drug development in recent years, treatment options remain limited. The major cause of HCC is chronic hepatitis B virus (HBV) infection. Despite the existence of a vaccine, more than 250 million individuals are chronically infected by HBV. Current antiviral therapies can repress viral replication but to date there is no cure for chronic hepatitis B. Of note, inhibition of viral replication reduces but does not eliminate the risk of HCC development. HBV contributes to liver carcinogenesis by direct and indirect effects. This review summarizes the current knowledge of HBV-induced host epigenetic alterations and their association with HCC, with an emphasis on the interactions between HBV proteins and the host cell epigenetic machinery leading to modulation of gene expression.

BRD4 inhibition sensitizes cervical cancer to radiotherapy by attenuating DNA repair

Cisplatin-based chemoradiotherapy is the recommended treatment for local advanced cervical cancer, but radioresistance remains one of the most important and unresolved clinical problems. Investigations have revealed aberrant epigenetic modifications as one of the chief culprits for the development of radioresistance. Here, we attempt to identify a radiosensitizer from an epigenetic drug synergy screen and explore the underlying mechanism. We integrated epigenetic inhibitors and radiotherapy in cervical cancer cell lines to identify potential radiosensitizers. We further verified the sensitization effect of the drug and the function of its target gene both in vitro and in vivo. Finally, we validated the clinical significance of its target gene in clinical cervical cancer specimens. We identified JQ1, a BRD4 inhibitor, as a potent radiosensitizer. Functional assays demonstrated that repressing BRD4 activity led to significant radiosensitization and potentiation of DNA damage in cervical cancer cell lines. By using RNA-seq to determine JQ1-mediated changes in transcription, we identified RAD51AP1 as a major BRD4 target gene involved in radiosensitivity. A dual-luciferase reporter assay and ChIP-qPCR showed that BRD4 binds to the promoter region of RAD51AP1 and promotes its transcription, whereas this activity was attenuated by BRD4 inhibition. The in vivo experiments also suggested a synergy between BRD4 inhibition and radiotherapy. High BRD4 expression was found to be related to a worse prognosis and radiation resistance. BRD4 inhibition sensitizes cervical cancer to radiotherapy by inhibiting RAD51AP1 transcription. The combination of JQ1 with radiotherapy merits further evaluation as a therapeutic strategy for improving local control in cervical cancer.