Histone deacetylase inhibitors in hepatocellular carcinoma: A therapeutic perspective

Recent Advances in RNA Interference-Based Therapy for Hepatocellular Carcinoma: Emphasis on siRNA

Even though RNA treatments were first proposed as a way to change aberrant signaling in cancer, research in this field is currently ongoing. The term "RNAi" refers to the use of several RNAi technologies, including ribozymes, riboswitches, Aptamers, small interfering RNA (siRNA), antisense oligonucleotides (ASOs), and CRISPR/Cas9 technology. The siRNA therapy has already achieved a remarkable feat by revolutionizing the treatment arena of cancers. Unlike small molecules and antibodies, which need administration every three months or even every two years, RNAi may be given every quarter to attain therapeutic results. In order to overcome complex challenges, delivering siRNAs to the targeted tissues and cells effectively and safely and improving the effectiveness of siRNAs in terms of their action, stability, specificity, and potential adverse consequences are required. In this context, the three primary techniques of siRNA therapies for hepatocellular carcinoma (HCC) are accomplished for inhibiting angiogenesis, decreasing cell proliferation, and promoting apoptosis, are discussed in this review. We also deliberate targeting issues, immunogenic reactions to siRNA therapy, and the difficulties with their intrinsic chemistry and transportation.

Ferroptosis in hepatocellular carcinoma, from mechanism to effect

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor worldwide, characterized by high malignancy and rapid progression. Most cases are diagnosed at intermediate to advanced stages. Current treatment methods have limited efficacy, resulting in high recurrence rates and poor prognosis. Radical hepatectomy remains the primary treatment for HCC, complemented by radiotherapy, chemotherapy, targeted therapy, and immunotherapy. Despite significant improvement in patient prognosis with radical hepatectomy, the five-year survival rate post-surgery remains low; thus necessitating exploration of more effective therapeutic approaches. Ferroptosis is a recently discovered form of cell death that can modulate the occurrence and development of HCC through various mechanisms. This article aims to elucidate the mechanism of ferroptosis and its impact on HCC development to provide novel insights for diagnosis and treatment.

Deciphering the tumour immune microenvironment of hepatocellular carcinoma

Current treatments for hepatocellular carcinoma (HCC) are less effective and prone to recurrence after surgery, so it's needed to seek new ideas for its therapy. Tumour immune microenvironment (TME) is crucial for the pathogenesis, development and metastasis of HCC. Interactions between immune cells and tumour cells significantly impact responses to immunotherapies and patient prognosis. In recent years, immunotherapies for HCC have shown promising potential, but the response rate is still unsatisfactory. Understanding their cross-talks is helpful for selecting potential therapeutic targets, predicting immunotherapy responses, determining immunotherapy efficacy, identifying prognostic markers and selecting individualized treatment options. In this paper, we reviewed the research advances on the roles of immune cells and multi-omic research associated with HCC pathogenesis and therapy, and future perspectives on TME.

Impact of Surgical Margin Width on Prognosis Following Resection of Hepatocellular Carcinoma Varies on the Basis of Preoperative Alpha-Feto Protein and Tumor Burden Score

BACKGROUND

We sought to examine the prognostic impact of margin width at time of hepatocellular carcinoma (HCC) resection relative to the alpha-feto protein tumor burden score (ATS).

PATIENTS AND METHODS

Patients who underwent curative-intent hepatectomy for HCC between 2000 and 2020 were identified from a multi-institutional database. The impact of margin width on overall survival and recurrence-free survival was examined relative to ATS using univariable and multivariable analyses.

RESULTS

Among 782 patients with HCC who underwent resection, median ATS was 6.5 [interquartile range (IQR) 4.3-10.2]. Most patients underwent R0 resection (n = 613, 78.4%); among patients who had an R0 resection, 325 (41.6%) had a margin width > 5 mm while 288 (36.8%) had a 0-5 mm margin width. Among patients with high ATS, an increasing margin width was associated with incrementally better overall and recurrence-free survival. In contrast, among patients with low ATS, margin width was not associated with long-term outcomes. On multivariable Cox regression analysis, each unit increase in ATS was independently associated with a 7% higher risk of death [hazard ratio (HR) 1.07; 95% confidence interval (CI) 1.03-1.11, p < 0.001]. While the incidence of early recurrence was not associated with margin width among patients with low ATS, wider margin width was associated with an incrementally lower incidence of early recurrence among patients with high ATS.

CONCLUSION

ATS, an easy-to-use composite tumor-related metric, was able to risk stratify patients following resection of HCC relative to overall survival and recurrence-free survival. The therapeutic impact of resection margin width had a variable impact on long-term outcomes relative to ATS.

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.

Hydroxymethylation and Epigenetic Drugs: New Insights into the Diagnosis and Treatment in Epigenetics of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly lethal and heterogeneous malignancy with multiple genetic alternations and complex signaling pathways. The complexity and multifactorial nature of HCC pose a tremendous challenge regarding its diagnosis and treatment. Emerging evidence has indicated an important regulatory role of epigenetic modifications in HCC initiation and progression. Epigenetic modifications are stably heritable gene expression traits caused by changing the accessibility of chromatin structure and genetic activity without alteration in the DNA sequence and have been gradually recognized as a hallmark of cancer. In addition, accumulating data suggest a potential value of altered hydroxymethylation in epigenetic modifications and therapeutics targeting the epigenetically mediated regulation. As such, probing the epigenetic field in the era of precision oncology is a valid avenue for promoting the accuracy of early diagnosis and improving the oncological prognosis of HCC patients. This review focuses on the diagnostic performance and clinical utility of 5-hydroxymethylated cytosine, the primary intermediate product of the demethylation process, for early HCC diagnosis and discusses the promising applications of epigenetic-based therapeutic regimens for HCC.

Transcription factors TEAD2 and E2A globally repress acetyl-CoA synthesis to promote tumorigenesis

Acetyl-coenzyme A (acetyl-CoA) plays an important role in metabolism, gene expression, signaling, and other cellular processes via transfer of its acetyl group to proteins and metabolites. However, the synthesis and usage of acetyl-CoA in disease states such as cancer are poorly characterized. Here, we investigated global acetyl-CoA synthesis and protein acetylation in a mouse model and patient samples of hepatocellular carcinoma (HCC). Unexpectedly, we found that acetyl-CoA levels are decreased in HCC due to transcriptional downregulation of all six acetyl-CoA biosynthesis pathways. This led to hypo-acetylation specifically of non-histone proteins, including many enzymes in metabolic pathways. Importantly, repression of acetyl-CoA synthesis promoted oncogenic dedifferentiation and proliferation. Mechanistically, acetyl-CoA synthesis was repressed by the transcription factors TEAD2 and E2A, previously unknown to control acetyl-CoA synthesis. Knockdown of TEAD2 and E2A restored acetyl-CoA levels and inhibited tumor growth. Our findings causally link transcriptional reprogramming of acetyl-CoA metabolism, dedifferentiation, and cancer.

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.

Polyphenols as Potent Epigenetics Agents for Cancer

Human diseases such as cancer can be caused by aberrant epigenetic regulation. Polyphenols play a major role in mammalian epigenome regulation through mechanisms and proteins that remodel chromatin. In fruits, seeds, and vegetables, as well as food supplements, polyphenols are found. Compounds such as these ones are powerful anticancer agents and antioxidants. Gallic acid, kaempferol, curcumin, quercetin, and resveratrol, among others, have potent anti-tumor effects by helping reverse epigenetic changes associated with oncogene activation and tumor suppressor gene inactivation. The role dietary polyphenols plays in restoring epigenetic alterations in cancer cells with a particular focus on DNA methylation and histone modifications was summarized. We also discussed how these natural compounds modulate gene expression at the epigenetic level and described their molecular targets in cancer. It highlights the potential of polyphenols as an alternative therapeutic approach in cancer since they modulate epigenetic activity.

Individualized Approach in the Surgical Management of Hepatocellular Carcinoma: Results from a Greek Multicentre Study

Simple Summary

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with expected increasing frequency in the next few decades. The Barcelona Clinic Liver Cancer (BCLC) Staging System is a widely adopted tool for guiding the therapeutic algorithms of patients with HCC. This classification has been guiding clinical practice for the last two decades. However, emerging data demonstrate that patients beyond the traditional criteria of operability or resectability can benefit from surgical treatment. We present the Greek multicentre experience of treating HCC within and beyond BCLC guidelines.

Abstract

Background: Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the third leading cause of death worldwide. The management of HCC is complex, with surgical treatment providing long-term survival in eligible patients. This study aims to present the experience of aggressive surgical management of HCC in Greece. Methods: This is a retrospective multicentre clinical study with 242 patients. Results: Most patients were male (79%) and had a median age of 71 yrs. According to the most recent BCLC criteria, 172 patients (71.1%) were classified as BCLC 0-A stage, 33 patients (13.6%) were classified as BCLC B, and 37 (15.3%) were classified as BCLC C. A total of 54% of the patients underwent major hepatectomy. Major postoperative morbidity was 15.6%, and the 90-day postoperative mortality rate was 4.5%. The median follow-up was 33.5 months. Three- and five-year overall survival was 65% and 48%, respectively. The median overall survival was 55 months. Significantly, five-year survival was 55% for BCLC A, and 34% and 21% for BCLC B and C, respectively. In univariate analysis, cirrhosis, type of resection (R status), and BCLC stage were associated with overall survival. Multivariate analysis indicated that R1 and R2 resections compared to R0, and BCLC C compared to BCLC 0-A, were independently associated with increased mortality. Conclusions: Aggressive surgical treatment of HCC offers satisfactory long-term survival prospects. A significant percentage (29%) of HCCs that underwent liver resection were of the intermediate and advanced BCLC stage. The management of patients with HCC should be discussed in multidisciplinary tumour board meetings on a case-by-case basis to be more effective.

β-Hydroxybutyrate upregulates FGF21 expression through inhibition of histone deacetylases in hepatocytes

Fibroblast growth factor 21 (FGF21) is secreted by hepatocytes as a peptide hormone to regulate glucose and lipid metabolism. FGF21 promotes hepatic ketogenesis and increases ketone body utilization in starvation. Histones are the target molecules of nutrients in regulating hepatic metabolic homeostasis. However, the effect of ketone bodies on FGF21 expression and the involvement of histones in it is not clear yet. The present study observed the effects of β-hydroxybutyrate (β-OHB), the main physiological ketone body, on FGF21 expression in human hepatoma HepG2 cells in vitro and in mice in vivo, and the role of histone deacetylases (HDACs) in β-OHB-regulated FGF21 expression was investigated. The results showed that β-OHB significantly upregulated FGF21 gene expression and increased FGF21 protein levels while it inhibited HDACs’ activity in HepG2 cells. HDACs’ inhibition by entinostat upregulated FGF21 expression and eliminated β-OHB-stimulated FGF21 expression in HepG2 cells. Intraperitoneal injections of β-OHB in mice resulted in the elevation of serum β-OHB and the inhibition of hepatic HDACs’ activity. Meanwhile, hepatic FGF21 expression and serum FGF21 levels were significantly increased in β-OHB-treated mice compared with the control. It is suggested that β-OHB upregulates FGF21 expression through inhibition of HDACs’ activity in hepatocytes.

Sodium butyrate inhibits aerobic glycolysis of hepatocellular carcinoma cells via the c‐myc/hexokinase 2 pathway

Aerobic glycolysis is a well‐known hallmark of hepatocellular carcinoma (HCC). Hence, targeting the key enzymes of this pathway is considered a novel approach to HCC treatment. The effects of sodium butyrate (NaBu), a sodium salt of the short‐chain fatty acid butyrate, on aerobic glycolysis in HCC cells and the underlying mechanism are unknown. In the present study, data obtained from cell lines with mouse xenograft model revealed that NaBu inhibited aerobic glycolysis in the HCC cells in vivo and in vitro. NaBu induced apoptosis while inhibiting the proliferation of the HCC cells in vivo and in vitro. Furthermore, the compound inhibited the release of lactate and glucose consumption in the HCC cells in vitro and inhibited the production of lactate in vivo. The modulatory effects of NaBu on glycolysis, proliferation and apoptosis were related to its modulation of hexokinase 2 (HK2). NaBu downregulated HK2 expression via c‐myc signalling. The upregulation of glycolysis in the HCC cells induced by sorafenib was impeded by NaBu, thereby enhancing the anti‐HCC effect of sorafenib in vitro and in vivo. Thus, NaBu inhibits the expression of HK2 to downregulate aerobic glycolysis and the proliferation of HCC cells and induces their apoptosis via the c‐myc pathway.

DNA methylation mediated downregulation of histone H3 variant H3.3 affects cell proliferation contributing to the development of HCC

Chromatin alterations brought by histone variants and modifications potentially regulate gene transcription from tumor initiation to progression. Histone H3.3 variant is one such epigenetic player important for disease progression and development. Though many studies have implicated H3.3 role in cancer progression and metastasis, its regulation, importance of specific modifications and chaperones have been not understood yet. We report DNA methylation mediated downregulation of histone H3 variant H3.3 in HCC and a concomitant increase in the level of the H3.2 variant. The loss of H3.3 in cancer tissues correlates with a decrease in the histone modifications associated with active transcription like H3K9/K14/K27Ac and H3K4Me3. The ectopic overexpression of H3.3 and H3.2 did not affect global PTMs and cell physiology, probably owing to the deregulation of specific histone chaperones CAF-1 (for H3.2) and HIRA (for H3.3) as observed in HCC tissues. Notably, knockdown of P150, a subunit of CAF-1 leads to a cell cycle arrest in S-phase in a neoplastic rat liver cell line, possibly due to the decrease in the histone levels necessary for DNA packaging. Remarkably, modulation of H3.3 in pre-neoplastic rat liver cells lead to an increase in cell proliferation and a decreased transcription of tumor suppressor genes, recapitulating the tumor cell phenotype. Our data suggests, inhibition of DNA methylation and histone deacetylation leads to the restoration of histone H3 variant expression in tumor cells.

Design, synthesis and biological evaluation of novel hybrids targeting mTOR and HDACs for potential treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major contributor to global cancer incidence and mortality. Many pathways are involved in the development of HCC and various proteins including mTOR and HDACs have been identified as potential drug targets for HCC treatment. In the present study, two series of novel hybrid molecules targeting mTOR and HDACs were designed and synthesized based on parent inhibitors (MLN0128 and PP121 for mTOR, SAHA for HDACs) by using a fusion-type molecular hybridization strategy. In vitro antiproliferative assays demonstrated that these novel hybrids with suitable linker lengths exhibited broad cytotoxicity against various cancer cell lines, with significant activity against HepG2 cells. Notably, DI06, an MLN0128-based hybrid, exhibited antiproliferative activity against HepG2 cells with an IC₅₀ value of 1.61 μM, which was comparable to those of both parent drugs (MLN0128, IC₅₀ = 2.13 μM and SAHA, IC₅₀ = 2.26 μM). In vitro enzyme inhibition assays indicated that DI06, DI07 and DI17 (PP121-based hybrid) exhibited nanomolar inhibitory activity against mTOR kinase and HDACs (e.g., HDAC1, HDAC2, HDAC3, HADC6 and HADC8). Cellular studies and western blot analyses uncovered that in HepG2 cells, DI06 and DI17 induced cell apoptosis by targeting mTOR and HDACs, blocked the cell cycle at the G0/G1 phase and suppressed cell migration. The potential binding modes of the hybrids (DI06 and DI17) with mTOR and HDACs were investigated by molecular docking. DI06 displayed better stability in rat liver microsomes than DI07 and DI17. Collectively, DI06 as a novel mTOR and HDACs inhibitor presented here warrants further investigation as a potential treatment of HCC.

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.

Lack of MOF Decreases Susceptibility to Hypoxia and Promotes Multidrug Resistance in Hepatocellular Carcinoma via HIF-1α

Hypoxia-inducible factor-1α (HIF-1α) promotes oncogenesis in hepatocellular carcinoma and is functionally linked to cell proliferation, chemoresistance, metastasis and angiogenesis. It has been confirmed that the low expression level of Males absent on the first (MOF) in hepatocellular carcinoma leads to poor prognosis of patients. However, potential regulatory mechanisms of MOF in response to hypoxia remain elusive. Our results demonstrate that MOF expression is negatively associated with HIF-1α expression in hepatocellular carcinoma tissues and in response to chloride-mimicked hypoxia in hepatocellular carcinoma cell lines. MOF regulates HIF-1α mRNA expression and also directly binds to HIF-1α to mediate HIF-1α N-terminal lysine acetylation, ubiquitination and degradation, with downstream effects on MDR1 levels. Functional inactivation of MOF enhances HIF-1α stability and causes cell tolerance to hypoxia that is insensitive to histone deacetylase inhibitor treatment. Dysfunction of MOF in hepatocellular carcinoma cells also results in chemoresistance to trichostatin A, sorafenib and 5-fluorouracil via HIF-1α. Our results suggest that MOF regulates hypoxia tolerance and drug resistance in hepatocellular carcinoma cells by modulating both HIF-1α mRNA expression and N-terminal acetylation of HIF-1α, providing molecular insight into MOF-dependent oncogenic function of hepatocellular carcinoma cells.

Combinatorial antitumor effects of amino acids and epigenetic modulations in hepatocellular carcinoma cell lines

Hepatocellular carcinoma (HCC) is a highly fatal form of liver cancer. Recently, the interest in using amino acids as therapeutic agents has noticeably grown. The present work aimed to evaluate the possible antiproliferative effects of selected amino acids supplementation or deprivation in human HCC cell lines and to investigate their effects on critical signaling molecules in HCC pathogenesis and the outcomes of their combination with the histone deacetylase inhibitor vorinostat. HepG2 and Huh7 cells were treated with different concentrations of L-leucine, L-glutamine, or L-methionine and cell viability was determined using MTT assay. Insulin-like growth factor 1 (IGF1), phosphorylated ribosomal protein S6 kinase (p70 S6K), p53, and cyclin D1 (CD1) protein levels were assayed using ELISA. Caspase-3 activity was assessed colorimetrically. L-leucine supplementation (0.8-102.4 mM) and L-glutamine supplementation (4-128 mM) showed dose-dependent antiproliferative effects in both cell lines but L-methionine supplementation (0.2-25.6 mM) only affected the viability of HepG2 cells. Glutamine or methionine deprivation suppressed the proliferation of HepG2 cells whereas leucine deprivation had no effect on cell viability in both cell lines. The combination between the effective antiproliferative changes in L-leucine, L-glutamine, and L-methionine concentrations greatly suppressed cell viability and increased the sensitivity to vorinostat in both cell lines. The growth inhibitory effects were paralleled with significant decreases in IGF-1, phospho p70 S6k, and CD1 levels and significant elevations in p53 and caspase-3 activity. Changes in amino acids concentrations could profoundly affect growth in HCC cell lines and their response to epigenetic therapy.

LPCAT1 overexpression promotes the progression of hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) remains one of the most common malignant neoplasms. Lysophosphatidylcholine acyltransferase 1 (LPCAT1) plays a key role in the lipid remodelling and is correlated with various neoplasms. Nonetheless, the biological functions and molecular mechanisms of LPCAT1 underlying HCC remain obscure.

METHODS

In the present study, we investigated the role of LPCAT1 in the progression of HCC. In-house RT-qPCR, tissue microarrays, and immunohistochemistry were performed to detect the expression levels and the clinical value of LPCAT1 in HCC. External datasets were downloaded to confirm the results. Proliferation, migration, invasiveness, cell cycle, and apoptosis assays were conducted to reveal the biological effects LPCAT1 has on SMMC-7721 and Huh7 cells. HCC differentially expressed genes and LPCAT1 co-expressed genes were identified to explore the molecular mechanisms underlying HCC progression.

RESULTS

LPCAT1 showed upregulated expression in 3715 HCC specimens as opposed to 3105 non-tumour specimens. Additionally, LPCAT1 might be an independent prognostic factor for HCC. LPCAT1-knockout hampered cellular proliferation, migration, and metastasis in SMMC-7721 and Huh7 cells. More importantly, the cell cycle and chemical carcinogenesis were the two most enriched signalling pathways.

CONCLUSIONS

The present study demonstrated that increased LPCAT1 correlated with poor prognosis in HCC patients and fuelled HCC progression by promoting cellular growth, migration, and metastasis.

Histone Deacetylase Inhibitors and Papillary Thyroid Cancer

BACKGROUND/AIM

Papillary Thyroid Cancer (PTC) is the most common type of endocrine malignancy. Although PTC has an excellent prognosis, the recurrent or metastatic disease could affect patients' survival. Recent studies show that Histone Deacetylase Inhibitors (HDACIs) might be promising anticancer agents against PTC. The aim of this review is to evaluate the role of HDACIs as an additional modality in PTC treatment and to depict the latest trends of current research on this field.

MATERIALS AND METHODS

This literature review was performed using the MEDLINE database. The search strategy included terms: "thyroid cancer", "papillary", "HDAC", "histone", and "deacetylase".

RESULTS

Agents, such as Suberoyl Anilide Hydroxamic Acid, Trichostatin A, Valproic Acid, Sodium butyrate, Panobinostat, Belinostat, Romidepsin, CUDC907 and N-Hydroxy-7-(2-naphthylthio)-Hepanomide have shown promising anti-cancer effects on PTC cell lines but fail to trigger a major response in clinical trials.

CONCLUSION

HDACIs have no significant effect as monotherapy against PTC, but further research needs to be conducted in order to investigate their potential effect when used as an additional modality.

Efficacy and safety of HDACIs in the treatment of metastatic or unresectable renal cell carcinoma with a clear cell phenotype: A systematic review and meta-analysis

BACKGROUND

In this study, we evaluated the efficacy and safety of histone deacetylase inhibitors (HDACIs) in the treatment of renal cell carcinoma (RCC).

METHODS

PubMed, EMBASE, the Cochrane Library, CNKI, and the Wanfang database were searched to retrieve studies describing the use of HDACIs for the treatment of RCC published between January 1, 2009, and January 1, 2021. Relevant studies were selected, and data were extracted. Then, a meta-analysis was performed using R 3.5.2 software.

RESULTS

The results showed that the objective response rate (ORR) of HDACIs used to treat RCC was 26% [95% confidence interval (95% CI): 0.19∼0.34] and that the 1-year progression-free survival (PFS) rate was 29% (95% CI: 0.14∼0.59). The ORR and PFS rate of the combination group were better than those of the monotherapy group, and the ORR and PFS rate of the selective HDACI group were better than those of the pan-HDACI group. The incidences of neutropenia and thrombocytopenia were higher and the incidence of fatigue was lower in the selective HDACI group than in the pan-HDACI group.

CONCLUSION

This study initially confirmed the efficacy and safety of HDACIs for the treatment of RCC. Due to the limitations of the included studies, more high-quality studies are needed to validate the conclusions.

Identification of New Biomarker for Prediction of Hepatocellular Carcinoma Development in Early-Stage Cirrhosis Patients

Background

Liver cirrhosis is one of the major drivers of hepatocellular carcinoma (HCC). In the present study, we aimed to identify and validate new biomarker for early prediction of HCC development in early-stage cirrhosis patients.

Methods

mRNA expression and clinical parameters of GSE63898, GSE89377, GSE15654, GSE14520, and TCGA-HCC cohort and ICGC-HCC cohort were downloaded for analysis. Wilcoxon test was performed to identify DEGs. Univariate and multivariate Cox regression analysis were used to develop the risk signature, and ROC analysis was performed to analyze the predictive accuracy and sensitivity of the risk signature.

Results

There were 42 DEGs (including 28 upregulated genes and 14 downregulated genes) found in early-stage liver cirrhosis patients before developing HCC from GSE1565442. Then, a risk signature consisting of 8 DEGs could effectively classify early-stage cirrhosis patients into high-risk group with shorter HCC development time and low-risk group with longer HCC development time from GSE15654. Multivariate Cox analysis indicated that the risk signature was an independent prognostic factor for the prediction of HCC development and ROC analysis showed that the signature exhibited good predictive efficiency in predicting 2-, 5-, and 10-year HCC development. Mechanistically, significantly higher proportions of CD8 T cells were found to be enriched in cirrhosis patients with low risk score, and higher CD8 T cells were associated with longer HCC development time. Besides, the signature was an independent prognostic factor for poorer prognosis of early-stage liver cirrhosis patients of GSE15654. Moreover, the signature could also separate HCC patients from healthy controls and was also associated with the poorer prognosis of HCC patients from three HCC cohorts. Finally, we also identified HDAC inhibitors, such as trichostatin A, to be a potential chemopreventive treatment for the prevention of HCC development by targeting risk signature based on CMap analysis.

Conclusion

A risk signature was developed and validated for early prediction of HCC development, which may be a useful tool to set up individualized follow-up interval schedules.

Sodium Valproate, a Histone Deacetylase Inhibitor, Provokes Reactive Oxygen Species-Mediated Cytotoxicity in Human Hepatocellular Carcinoma Cells

BACKGROUND AND AIM

Sodium valproate (SV), a novel class of histone deacetylases (HDACs) inhibitors commonly used as an antiepileptic drug. HDAC inhibitors are known to possess anticancer potentials. In this study, we investigated the cytotoxic potential of SV in human hepatocellular carcinoma (HepG2 cells) cell line.

METHODS

MTT assay was used to analyze cytotoxicity. Intracellular ROS and cytochrome c expression were analyzed by fluorescence microscopy. Morphology-related apoptosis was analyzed by dual staining with acridine orange/ethidium bromide. Caspase 3 protein expression was investigated by Western blotting analysis.

RESULTS

Sodium valproate treatments in HepG2 cells caused significant and dose-dependent cytotoxicity. Intracellular ROS was remarkably increased in the cells which are treated with SV and caused early and late apoptosis as evidenced by dual staining. SV-treated cells expressed cytochrome c and caspase 3 protein expression.

CONCLUSION

These results suggest the cytotoxic potentials of SV in HepG2 cells. This study may give an important clue for the inclusion of SV as an adjuvant along with standard anticancer agents after necessary in vivo and clinical studies.

Butyrate-containing structured lipids act on HDAC4, HDAC6, DNA damage and telomerase activity during promotion of experimental hepatocarcinogenesis

Hepatocellular carcinoma (HCC) presents with a high treatment resistance and poor prognosis. Early diagnosis and preventive approaches such as chemoprevention are essential for the HCC control. Therefore, we evaluated the chemopreventive effects of butyrate-containing structured lipids (STLs) administered during the promotion stage of hepatocarcinogenesis in rats submitted to the 'resistant hepatocyte' (RH) model. Administration of butyrate-containing STLs inhibited the incidence and mean number of visible hepatic nodules per rat and reduced the number and area of glutathione S-transferase placental form-positive (GST-P+) preneoplastic focal lesions in the livers. This was accompanied by the induction of apoptosis and an increased level of hepatic butyric acid. Treatment with butyrate-containing STLs resulted in increased histone H3 lysine 9 (H3K9) acetylation, reduction of total histone deacetylase (HDAC) activity, and lower levels of HDAC4 and HDAC6 proteins. The chemopreventive effect of butyrate-containing STLs was also associated with the increased nuclear compartmentalization of p53 protein and reduced expression of the Bcl-2 protein. In addition, rats treated with butyrate-containing STLs showed decreased DNA damage and telomerase activity in the livers. These results demonstrate that the suppressive activity of butyrate-containing STLs is associated with inhibition of elevated during hepatocarcinogenesis chromatin-modifying proteins HDAC4 and HDAC6, subcellular redistribution of the p53 protein, and decreased DNA damage and telomerase activity.

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.

Identification of Core Genes Related to Progression and Prognosis of Hepatocellular Carcinoma and Small-Molecule Drug Predication

Background

Hepatocellular carcinoma (HCC) is one of the most leading causes of cancer death with a poor prognosis. However, the underlying molecular mechanisms are largely unclear, and effective treatment for it is limited. Using an integrated bioinformatics method, the present study aimed to identify the key candidate prognostic genes that are involved in HCC development and identify small-molecule drugs with treatment potential.

Methods and Results

In this study, by using three expression profile datasets from Gene Expression Omnibus database, 1,704 differentially expressed genes were identified, including 671 upregulated and 1,033 downregulated genes. Then, weighted co-expression network analysis revealed nine modules are related with pathological stage; turquoise module was the most associated module. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway analyses (KEGG) indicated that these genes were enriched in cell division, cell cycle, and metabolic related pathways. Furthermore, by analyzing the turquoise module, 22 genes were identified as hub genes. Based on HCC data from gene expression profiling interactive analysis (GEPIA) database, nine genes associated with progression and prognosis of HCC were screened, including ANLN, BIRC5, BUB1B, CDC20, CDCA5, CDK1, NCAPG, NEK2, and TOP2A. According to the Human Protein Atlas and the Oncomine database, these genes were highly upregulated in HCC tumor samples. Moreover, multivariate Cox regression analysis showed that the risk score based on the gene expression signature of these nine genes was an independent prognostic factor for overall survival and disease-free survival in HCC patients. In addition, the candidate small-molecule drugs for HCC were identified by the CMap database.

Conclusion

In conclusion, the nine key gene signatures related to HCC progression and prognosis were identified and validated. The cell cycle pathway was the core pathway enriched with these key genes. Moreover, several candidate molecule drugs were identified, providing insights into novel therapeutic approaches for HCC.

Platycodin D reverses histone deacetylase inhibitor resistance in hepatocellular carcinoma cells by repressing ERK1/2-mediated cofilin-1 phosphorylation

BACKGROUND

Chemoresistance remains the main obstacle in hepatocellular carcinoma (HCC) therapy. Despite significant advances in HCC therapy, HCC still has a poor prognosis. Thus, there is an urgent need to identify a treatment target to reverse HCC chemotherapy resistance. Platycodon grandiflorus (PG) is a perennial herb that has been used as food and traditional Chinese medicine for thousands of years in Northeast Asia. Platycodin D (PD), a main active triterpenoid saponin found in the root of PG, has been reported to possess anticancer properties in several cancer cell lines, including HCC; however, the reversal effect of this molecule on HCC chemoresistance remains largely unknown.

PURPOSE

This study aimed to investigate the role and the mechanism of PD-mediated reversal of the histone deacetylase inhibitor (HDACi) resistance in HCC cells.

METHODS

Human HCC cells (HA22T) and HDACi-resistant (HDACi-R) cells were used. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Combination index was used to calculate the synergism potential. Expression of ERK1/2 (total/phospho), cofilin-1 (total/phospho) and apoptosis-related protein was determined using western blotting. Mitochondrial membrane potential was assessed using the JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide) probe. Apoptosis was detected using the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Mitochondrial reactive oxygen species generation was measured using the MitoSOX Red fluorescent probe.

RESULTS

We found that PD treatment inhibited cell viability both in HA22T HCC and HDACi-R cells. Inhibition of ERK1/2 by PD98059 could reverse drug resistance in HDACi-R cells treated with PD98059 and PD. Nevertheless, pre-treatment with U46619, an ERK1/2 activator, rescued PD-induced apoptosis by decreasing levels of apoptosis-related proteins in HCC cells. The combined treatment of PD with apicidin a powerful HDACi, dramatically enhanced the apoptotic effect in HDACi-R cells.

CONCLUSION

For the first time, we showed that PD reversed HDACi resistance in HCC by repressing ERK1/2-mediated cofilin-1 phosphorylation. Thus, PD can potentially be a treatment target to reverse HCC chemotherapy resistance in future therapeutic trials.

Histone Deacetylases (HDACs) in Gastric Cancer: An Update of their Emerging Prognostic and Therapeutic Role

Chemotherapy resistance is a rising concern in Gastric Cancer (GC) and has led to the investigation of various cellular compounds. Α functional equilibrium of histone acetylation and deacetylation was discovered in all cells, regulated by Histone Acetyltransferases and Deacetylases (HDACs), controlling chromatin coiling status and changing gene expression appropriately. In accordance with recent research, this equilibrium can be dysregulated in cancer cells aiding in the process of carcinogenesis and tumor progression by altering histone and non-histone proteins affecting gene expression, cell cycle control, differentiation, and apoptosis in various malignancies. In addition, increased HDAC expression in GC cells has been associated with increased stage, tumor invasion, nodal metastases, increased distant metastatic potential, and decreased overall survival. HDAC inhibitors could be used as treatment regimens for GC patients and could develop important synergistic interactions with chemotherapy drugs. The aim of this article is to review the molecular identity and mechanism of action of HDAC inhibitors, as well as highlight their potential utility as anti-cancer agents in GC.

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.

Sodium Butyrate Inhibits Neovascularization Partially via TNXIP/VEGFR2 Pathway

Control of neovascularization with small molecules is a promising tactics. Here, we tested the roles of sodium butyrate (NaBu) on the neovascularization and primary explained its underlining molecular links. We used models including cell and ex vivo culture of choroid and mouse, as well as the biochemical and cellular techniques, to confirm our hypothesis. We found that treating HUVEC cells with NaBu (both 2.5 mM and 5 mM) significantly inhibited its ability in tube formation and proliferation. This inhibitory effect was also observed in choroid sprouting experiments, compared to the control. Interestingly, the choroid sprouting suppressed by NaBu can proliferate again after removing it, indicating that the cell cycle progression might be arrested. The laser-induced choroid neovascularization (CNV) was significantly alleviated by assessing the CNV size (decreased to 0.73 fold) in contrast with the vehicle control group after 2.5 mM NaBu injection for 7 days. Mechanistically, we found an enhanced TXNIP expression in response to NaBu treatment in all the three models. Overexpressing TXNIP in HUVEC cells blocked its tube formation and inhibited its proliferation; on the other hand, knocking down its expression with shRNA reversed those phenotypes in context of NaBu treatment. Further investigation showed the expression of VEGF receptor 2 (VEGFR2) in HUVEC cells was regulated by TXNIP undergoing NaBu treatment. We therefore argued that NaBu inhibited neovascularization partially through TXNIP-regulated VEGFR2 signal pathway.

Liver-Targeting Class I Selective Histone Deacetylase Inhibitors Potently Suppress Hepatocellular Tumor Growth as Standalone Agents

Dysfunctions in epigenetic regulation play critical roles in tumor development and progression. Histone deacetylases (HDACs) and histone acetyl transferase (HAT) are functionally opposing epigenetic regulators, which control the expression status of tumor suppressor genes. Upregulation of HDAC activities, which results in silencing of tumor suppressor genes and uncontrolled proliferation, predominates in malignant tumors. Inhibition of the deacetylase activity of HDACs is a clinically validated cancer therapy strategy. However, current HDAC inhibitors (HDACi) have elicited limited therapeutic benefit against solid tumors. Here, we disclosed a class of HDACi that are selective for sub-class I HDACs and preferentially accumulate within the normal liver tissue and orthotopically implanted liver tumors. We observed that these compounds possess exquisite on-target effects evidenced by their induction of dose-dependent histone H4 hyperacetylation without perturbation of tubulin acetylation status and G0/G1 cell cycle arrest. Representative compounds 2 and 3a are relatively non-toxic to mice and robustly suppressed tumor growths in an orthotopic model of HCC as standalone agents. Collectively, our results suggest that these compounds may have therapeutic advantage against HCC relative to the current systemic HDACi. This prospect merits further comprehensive preclinical investigations.

In vitro high-throughput drug sensitivity screening with patient-derived primary cells as a guide for clinical practice in hepatocellular carcinoma-A retrospective evaluation

AIM

The aim of the study was to determine the clinical value of in vitro high-throughput drug sensitivity screening with primary hepatocellular carcinoma cells to select drugs for adjuvant chemotherapy.

METHODS

This study included 162 patients who underwent hepatectomy from September 2013 to December 2016. The patients were divided into a drug sensitivity screening group and an empirical treatment group. High-throughput drug sensitivity screening using primary HCC cells was carried out and, based on the test results, effective drugs were selected for treatment. Patients in the empirical group were treated with commonly used drugs, according to the clinicians' preferences. Clinical efficacy, i.e., disease-free survival (DFS) time, was compared between the two groups.

RESULTS

Most patients with HCC showed extensive resistance to known chemotherapeutic drugs. However, bortezomib, regorafenib, sorafenib, romidepsin, hydroxycamptothecin and adriamycin+oxaliplatin showed strong anti-HCC activity in the sensitivity assay. Comparing clinical efficacy, the overall median DFS of patients in the drug sensitivity screening group was significantly better than that of patients in the empirical treatment group (17.00±3.80 months vs. 9.00±1.18 months, P=0.001). Median DFS times in the TACE group were 9.00±4.07 months vs. 7.00±1.06 months (P=0.014) and median DFS times in the oral drugs group were 16.80±3.98 months vs. 10.00±0.81 months (P=0.024). Patients DFS was 69.4%, 62.5% at 1-, 2- years, respectively, for patients with drug sensitivity screening, and 48.5%, 37.8% at 1-, 2- years, respectively, for patients with empirical treatment.

CONCLUSION

High-throughput drug sensitivity screening can be successfully used to screen chemotherapeutic drugs for efficacy against HCC and the efficacious drugs can be used in postoperative adjuvant chemotherapy of HCC patients. This treatment paradigm is safe and reliable, and improves survival compared with empirical chemotherapy.

Sodium Butyrate Combined with Docetaxel for the Treatment of Lung Adenocarcinoma A549 Cells by Targeting Gli1

Purpose

This study is aimed to investigate the combined treating efficacy of sodium butyrate and docetaxel on proliferation and apoptosis of the lung adenocarcinoma A549 cell line based on Gli1 regulation in vitro and in vivo.

Materials and Methods

RNA interference method was used to overexpress Gli1 in A549 cells. Cells were treated with varying concentrations of sodium butyrate, docetaxel or both in combination. CCK-8, colony formation assay, Hoechst 33258 staining, flow cytometry and TUNEL assay were employed to detect proliferation, cell cycle and apoptosis. qRT-PCR and Western blot analysis were applied to detect the mRNA and protein expression of Gli1. In vivo tumorigenicity was detected by tumor transplantation in nude mice. Downstream protein levels of Gli1 were detected using Western blot assay.

Results

It was found that sodium butyrate or docetaxel alone, respectively, inhibited proliferation and promoted apoptosis of A549 cells in vitro and in vivo, while the combination of the two generated significantly higher responses, which were also effective in another lung adenocarcinoma cell line H1299. Furthermore, the combined therapy had an additive effect in suppressing Gli1 expression and regulating the expression of its downstream proteins that involve in proliferation, cell cycle and apoptosis of A549 cells in vitro and in vivo, including decreased protein expression of Ki-67, CDK1, CDK2, Cyclin D1, Bcl-2 and Survivin, and increased protein expression of Cyclin A, p21, Bax and cleaved-Caspase 3. On the other hand, Gli1 overexpression perceptibly reversed the above-mentioned additive effect in vitro and in vivo.

Conclusion

This study demonstrates that the combined therapy of sodium butyrate and docetaxel additively inhibits proliferation and promotes apoptosis of A549 lung adenocarcinoma cells via suppressing Gli1 expression in vitro and in vivo. Targeting Gli1 by the combined therapy may provide new insights into the therapeutic management of patients with lung adenocarcinoma.

2-O-Methylmagnolol, a Magnolol Derivative, Suppresses Hepatocellular Carcinoma Progression via Inhibiting Class I Histone Deacetylase Expression

Magnolia officinalis is widely used in Southeast Asian countries for the treatment of fever, headache, diarrhea, and stroke. Magnolol is a phenolic compound extracted from M. officinalis, with proven antibacterial, antioxidant, anti-inflammatory, and anticancer activities. In this study, we modified magnolol to synthesize a methoxylated derivative, 2-O-methylmagnolol (MM1), and investigated the use of MM1, and magnolol in the treatment of liver cancer. We found that both magnolol and MM1 exhibited inhibitory effects on the growth, migration, and invasion of hepatocellular carcinoma (HCC) cell lines and halted the cell cycle at the G1 phase. MM1 also demonstrated a substantially better tumor-suppressive effect than magnolol. Further analysis suggested that by inhibiting class I histone deacetylase expression in HCC cell lines, magnolol and MM1 induced p21 expression and p53 activation, thereby causing cell cycle arrest and inhibiting HCC cell growth, migration, and invasion. Subsequently, we verified the significant tumor-suppressive effects of magnolol and MM1 in an animal model. Collectively, these findings demonstrate the anti-HCC activities of magnolol and MM1 and their potential for clinical use.

Valproic acid overcomes sorafenib resistance by reducing the migration of Jagged2-mediated Notch1 signaling pathway in hepatocellular carcinoma cells

Sorafenib resistance is a classic problem related to the treatment of advanced hepatocellular carcinoma (HCC). There is a recognized need to explore new drug resistance mechanisms and develop novel strategies to overcome the acquired resistance to sorafenib. Although one study has showed that the anti-epileptic drug valproic acid (VPA) could sensitize transforming growth factor-β (TGF-β)-induced sorafenib-resistant HCC cells, it is unclear whether VPA could reverse resistance to long-term clinical treatment with sorafenib. In this study, we successfully established sorafenib-resistant HCC cells by long-term sorafenib exposure. Compared with sensitive HCC cells, the proliferation, anti-apoptotic capability and migration of the sorafenib-resistant cells were enhanced. In addition, we found that VPA combined with sorafenib could overcome drug resistance by downregulating Jagged2-mediated Notch1 signaling pathway and epithelial-mesenchymal transition (EMT)-related proteins. Furthermore, the combination of VPA and sorafenib could obviously increase the sensitivity of drug-resistant cells in vitro and synergistically suppress tumor growth in vivo. These results provided a new insight that the use of VPA in combination with sorafenib was an effective method for clinically solving the problem of sorafenib resistance by modulating the Jagged2-mediated Notch1 signaling pathway and reversing the EMT phenotype.

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.

Targeting Histone Deacetylase 6 Reprograms Interleukin-17-Producing Helper T Cell Pathogenicity and Facilitates Immunotherapies for Hepatocellular Carcinoma

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is often accompanied by resistance to immunotherapies despite the presence of tumor-infiltrating lymphocytes. We report that histone deacetylase 6 (HDAC6) represses interleukin-17 (IL-17)-producing helper T (TH 17) cell pathogenicity and the antitumor immune response, dependent on its deacetylase activity.

APPROACH AND RESULTS

Adoptive transfer of HDAC6-deficient TH 17 cells impedes HCC growth, dependent on elevated IL-17A, by enhancing the production of antitumor cytokine and cluster of differentiation 8-positive (CD8+) T cell-mediated antitumor responses. Intriguingly, HDAC6-depleted T cells trigger programmed cell death protein 1 (PD-1)-PD-1 ligand 1 expression to achieve a strong synergistic effect to sensitize advanced HCC to an immune checkpoint blocker, while blockade of IL-17A partially suppresses it. Mechanistically, HDAC6 limits TH 17 pathogenicity and the antitumor effect through regulating forkhead box protein O1 (FoxO1). HDAC6 binds and deacetylates cytosolic FoxO1 at K242, which is required for its nuclear translocation and stabilization to repress retinoic acid-related orphan receptor gamma (RoRγt), the transcription factor of TH 17 cell. This regulation of HDAC6 for murine and human TH 17 cell is highly conserved.

CONCLUSIONS

These results demonstrate that targeting the cytosolic HDAC6-FoxO1 axis reprograms the pathogenicity and antitumor response of TH 17 cells in HCC, with a pathogenicity-driven responsiveness to facilitate immunotherapies.

Histone Deacetylases Inhibitors in Neurodegenerative Diseases, Neuroprotection and Neuronal Differentiation

Histone deacetylases (HADC) are the enzymes that remove acetyl group from lysine residue of histones and non-histone proteins and regulate the process of transcription by binding to transcription factors and regulating fundamental cellular process such as cellular proliferation, differentiation and development. In neurodegenerative diseases, the histone acetylation homeostasis is greatly impaired, shifting towards a state of hypoacetylation. The histone hyperacetylation produced by direct inhibition of HDACs leads to neuroprotective actions. This review attempts to elaborate on role of small molecule inhibitors of HDACs on neuronal differentiation and throws light on the potential of HDAC inhibitors as therapeutic agents for treatment of neurodegenerative diseases. The role of HDACs in neuronal cellular and disease models and their modulation with HDAC inhibitors are also discussed. Significance of these HDAC inhibitors has been reviewed on the process of neuronal differentiation, neurite outgrowth and neuroprotection regarding their potential therapeutic application for treatment of neurodegenerative diseases.

The effects of epigenetic modification on the occurrence and progression of liver diseases and the involved mechanism

Introduction: Epigenetic modification is a type of gene expression and regulation that does not involve changes in DNA sequences. An increasing number of studies have proven that epigenetic modifications play an important role in the occurrence and progression of liver diseases through the gene regulation and protein expressions of hepatocellular lipid metabolism, inflammatory reaction, cell proliferation, and activation, etc.Areas covered: In this study, we elaborated and analyzed the underlying functional mechanism of epigenetic modification in alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), liver fibrosis (LF), viral hepatitis, hepatocellular carcinoma (HCC), and research progress of recent years.Expert opinion: The further understanding of epigenetic mechanisms that can regulate gene expression and cell phenotype leads to new insights in epigenetic control of chronic liver disease. Currently, hepatologists are exploring the role of DNA methylation, histone/chromatin modification, and non-coding RNA in specific liver pathology. These findings have led to advances in direct epigenetic biomarker testing of patient tissue or body fluid specimens, as well as quantitative analysis. Based on these findings, drug validation of some targets involved in the epigenetic mechanism of liver disease is gradually being carried out clinically.

CHD4/NuRD complex regulates complement gene expression and correlates with CD8 T cell infiltration in human hepatocellular carcinoma

Backgrounds

The NuRD (Nucleosome Remodeling and Deacetylation) complex is a repressive complex in gene transcription by modulating chromatin accessibility of target genes to transcription factors and RNA polymerase II. Although individual subunits of the complex have been implicated in many other cancer types, the complex’s role in human hepatocellular carcinoma (HCC) is not fully understood. More importantly, the NuRD complex has not yet been investigated as a whole in cancers.

Methods

We analyzed the expression of the NuRD complex in HCC and evaluated the prognostic value of NuRD complex expression in HCC using the RNA-seq data obtained from the TCGA project. We examined the effect of CHD4 knockdown on HCC cell proliferation, apoptosis, migration, invasion, epithelial-mesenchymal transition, colony-forming ability, and on complement gene expression. We also performed bioinformatic analyses to investigate the correlation between the NuRD complex expression and immune infiltration.

Results

We found that nine subunits, out of 14 subunits of the NuRD complex examined, were significantly overexpressed in HCC, and their expression levels were positively correlated with cancer progression. More importantly, our data also demonstrated that these subunits tended to be overexpressed as a whole in HCC. Subsequent studies demonstrated that knockdown of CHD4 in HCC cells inhibits cell proliferation, migration, invasion, and colony-forming ability and promotes apoptosis of HCC cells, indicating that the CHD4/NuRD complex plays oncogenic roles in HCC. Further analysis revealed that the CHD4/NuRD complex regulates complement gene expression in HCC. Intriguingly, we found that the CHD4/NuRD complex expression was inversely correlated with CD8 T cell infiltration in HCC.

Conclusions

Our data demonstrate that the CHD4/NuRD complex plays an oncogenic role in human HCC and regulates complement gene expression in HCC cells. The results of inverse correlation between the CHD4/NuRD complex and CD8 T cell and DC cell infiltration in HCC suggest that the CHD4/NuRD complex not only plays direct regulatory roles in HCC cells, but also has an impact on the immune microenvironment of HCC.

New landscapes and horizons in hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC), is the sixth most frequent form of cancer and leads to the fourth highest number of deaths each year. HCC results from a combination of environmental factors and aging as there are driver mutations at oncogenes which occur during aging. Most of HCCs are diagnosed at advanced stage preventing curative therapies. Treatment in advanced stage is a challenging and pressing problem, and novel and well-tolerated therapies are urgently needed. We will discuss further advances beyond sorafenib that target additional signaling pathways and immune checkpoint proteins. The scenario of possible systemic therapies for patients with advanced HCC has changed dramatically in recent years. Personalized genomics and various other omics approaches may identify actionable biochemical targets, which are activated in individual patients, which may enhance therapeutic outcomes. Further studies are needed to identify predictive biomarkers and aberrantly activated signaling pathways capable of guiding the clinician in choosing the most appropriate therapy for the individual patient.

Immunotherapy utilization for hepatobiliary cancer in the United States: disparities among patients with different socioeconomic status

Background

Patients with advanced hepatobiliary cancer (HBC) have a dismal prognosis and limited treatment options. Immunotherapy has been considered as a promising treatment, especially for cancers not amenable to surgery.

Methods

Between 2004, and 2015, patients diagnosed with hepatocellular carcinoma (HCC), intra- and extrahepatic cholangiocarcinoma and gallbladder cancer (GBC) were identified in the National Cancer Database.

Results

Among 249,913 patients with HBC, only 585 (0.2%) patients received immunotherapy. Among patients who received immunotherapy, most patients were diagnosed between 2012 and 2015, had private insurance, as well as an income ≥$46,000 and were treated at an academic facility. The use of immunotherapy among HBC patients varied by diagnosis (HCC, 67.7%; bile duct cancer, 14%). On multivariable analysis, a more recent period of diagnosis (OR 1.80, 95% CI: 1.44-2.25), median income >$46,000 (OR 1.43, 95% CI: 1.11-1.87), and higher tumor stage (stage III, OR 2.22, 95% CI: 1.65-3.01; stage IV, OR 3.24, 95% CI: 2.41-4.34) were associated with greater odds of receiving immunotherapy.

Conclusions

Overall utilization of immunotherapy in the US among patients with HBC was very low, yet has increased over time. Certain socioeconomic factors were associated with an increased likely of receiving immunotherapy, suggesting disparities in access of patients with lower socioeconomic status.

Sensitization to oxidative stress and G2/M cell cycle arrest by histone deacetylase inhibition in hepatocellular carcinoma cells

Oxidative stress resistance in cancer cells has contributed to multi-drug resistance, which poses a serious challenge to cancer therapy. To surmount this, combinatorial treatment involving anticancer drugs and histone deacetylase inhibitors (HDACi) have emerged as a chemotherapeutic option. Yet, HDACi's role in redox states of cancer cells still requires elucidation. In the present study, we hypothesized that HDACi sensitizes cancer cells to oxidative stress and results in G2/M cell cycle arrest. Cell viability and cell cycle were analyzed using Cell Counting Kit 8 (CCK8) and fluorescent activated cell sorting (FACS), respectively. The transcriptomes of cells were investigated by massive analysis of cDNA end (MACE). Expression of mRNA and proteins were analyzed by quantitative real-time PCR (qPCR) and Western blot, respectively. Intracellular oxidative stress induced by tert-Butyl hydroperoxide (tBHP) reduced cell viability and resulted in G2/M cell cycle arrest in a dose-dependent manner in hepatocellular carcinoma (HCC) cells. The effects of sorafenib on cell cycle arrest and HCC viability were enhanced through HDACi treatment. MACE revealed that genes related to progression of G2/M cell cycle including Foxm1, Aurka, Plk1, and Ccnb1 were significantly down-regulated in tBHP and HDACi-treated HepG2 cells. Inhibition of FOXM1 with thiostrepton also resulted in reduced cell viability and expression of FOXM1 target genes such as Aurka, Plk1, and Ccnb1. These results indicate that HDACi sensitizes HepG2 cells to oxidative stress and results in G2/M cell cycle arrest via down-regulation of FOXM1, which plays a key role in progression of G2/M cell cycle.

Histone deacetylase inhibitor MGCD0103 causes cell cycle arrest, apoptosis, and autophagy in liver cancer cells

Background: Liver cancer is a common cause of cancer-related death all over the world. MGCD0103, a histone deacetylase inhibitor, exerts antitumor effect on various cancers. However, its role in liver cancer remains unclear.

Methods: The effect of MGCD0103 on HepG2 and Huh7 cells was verified by several experiments such as cell viability assay, colony formation assay, cell cycle analysis, apoptosis analysis, reactive oxygen species (ROS) assay, western blotting, immunohistochemistry, and xenograft assay.

Results: Cell viability and colony formation assays showed that MGCD0103 inhibited the proliferation of liver cancer cells in vitro. Flow cytometry and western blotting analysis demonstrated that MGCD0103 induced G2/M phase arrest and mitochondrial-related apoptosis. A pan-caspase inhibitor and ROS scavenger inhibited apoptosis induced by MGCD0103. What's more, MGCD0103 led to autophagy associated with cell death and an autophagy inhibitor inhibited apoptosis and autophagy induced by MGCD0103. Ultimately, MGCD0103 attenuated tumor growth but did not show significant systemic toxicity in animal model.

Conclusions: MGCD0103 suppressed the growth of liver cancer cells in vitro and in vivo. It could serve as a novel therapeutic approach for liver cancer.

Nicotinamide Phosphoribosyltransferase (NAMPT) Is a New Target of Antitumor Agent Chidamide

Chidamide is a histone deacetylase (HDAC) inhibitor that is currently used to treat cutaneous T-cell lymphoma in clinic. Herein nicotinamide phosphoribosyltransferase (NAMPT) was identified to be a new target of chidamide on the basis of the pharmacophore analysis, molecular docking, biological assays, inhibitor design, and structure-activity relationship study. The polypharmacology of chidamide will provide important information for better understanding its antitumor mechanism. Also, design of dual NAMPT/HDAC inhibitors may serve as an effective strategy to develop novel antitumor agents.

Dissimilar Appearances Are Deceptive-Common microRNAs and Therapeutic Strategies in Liver Cancer and Melanoma

: In this review, we summarize the current knowledge on miRNAs as therapeutic targets in two cancer types that were frequently described to be driven by miRNAs-melanoma and hepatocellular carcinoma (HCC). By focusing on common microRNAs and associated pathways in these-at first sight-dissimilar cancer types, we aim at revealing similar molecular mechanisms that are evolved in microRNA-biology to drive cancer progression. Thereby, we also want to outlay potential novel therapeutic strategies. After providing a brief introduction to general miRNA biology and basic information about HCC and melanoma, this review depicts prominent examples of potent oncomiRs and tumor-suppressor miRNAs, which have been proven to drive diverse cancer types including melanoma and HCC. To develop and apply miRNA-based therapeutics for cancer treatment in the future, it is essential to understand how miRNA dysregulation evolves during malignant transformation. Therefore, we highlight important aspects such as genetic alterations, miRNA editing and transcriptional regulation based on concrete examples. Furthermore, we expand our illustration by focusing on miRNA-associated proteins as well as other regulators of miRNAs which could also provide therapeutic targets. Finally, design and delivery strategies of miRNA-associated therapeutic agents as well as potential drawbacks are discussed to address the question of how miRNAs might contribute to cancer therapy in the future.

Liver Tumor Microenvironment

The tumor microenvironment (TME) has recently been recognized as an important part of tumor development and growth. TME is a dynamic system orchestrated by immune, cancer and inflammatory cells, as well as the stromal tissue and surrounding extracellular matrix. While TME of primary hepatic tumors is usually characterized by a strong inflammatory background, the TME of liver metastases typically consists of otherwise healthy liver tissue. Chronic inflammation and hypoxia are key to the development and progression of primary liver cancer. The injury caused by chronic inflammation creates a condition of immune evasion that initiates a cascade of events that eventually leads to liver carcinogenesis.With liver metastases, primary tumors "prime" the target organs via secreting factors that induce expansion of myeloid cell populations and create a solid ground for successful cancer settlement. Once in the liver, metastatic cells begin a neovascularization process that is driven mainly by VEGF and FGF. Due to high mortality rates associated with liver cancer, as well as the limited effective treatment options for advanced disease, new therapies are urgently needed. Targeting a single molecule in a number of interactions between the tumor and the TME is highly unlikely to reduce tumor growth. Future trials should focus on combination therapies (i.e. targeted therapies combined with immunotherapy) to treat liver malignancies efficiently.

AR-42: A Pan-HDAC Inhibitor with Antitumor and Antiangiogenic Activities in Esophageal Squamous Cell Carcinoma

Purpose

Esophageal squamous cell carcinoma (ESCC) is a refractory malignancy with high morbidity and mortality. Thus, there is an urgent need to find effective targets and agents for ESCC treatment. The purpose of this study was to assess the anti-ESCC effects of a pan-histone deacetylase (HDAC) inhibitor AR-42 and its mechanisms of action.

Methods

Immunohistochemical staining was performed to detect HDAC1 expression in ESCC and adjacent tissue samples. MTT assay, Edu cell proliferation test, flow cytometry, and subcutaneous xenograft were used to assess the anti-ESCC effects of AR-42; furthermore, the antiangiogenic activity of AR-42 was evaluated using endothelial cell migration, invasion, and tube formation assays as well as zebrafish angiogenesis assay. Western blot analysis was performed to explore the underlying mechanism of the anti-ESCC activity of AR-42.

Results

HDAC1-positive expression was much higher in ESCC cells than in paracancerous tissues, and the elevated HDAC1 expression was a strong indicator of lymph node metastasis and a more advanced TNM stage of ESCC. Moreover, AR-42 potently suppressed ESCC cell growth through cellular proliferation inhibition and apoptosis induction. Moreover, AR-42 displayed a moderate antiangiogenic activity, and it could significantly inhibit the migration, invasion and tubulogenesis of human umbilical vein endothelial cells as well as intersegmental vessel formation in zebrafish at micromolar concentrations. More importantly, the inhibitory activity of AR-42 on ESCC cells and angiogenesis could also be observed in the TE-1 xenograft model. Further studies showed that AR-42 exerts its anti-ESCC effects mainly by upregulating the expression of p21 and blocking the transduction of multiple signaling cascades related to tumor growth, especially Stat3-mediated signaling.

Conclusion

Overall, AR-42 has significant potency for inhibiting ESCC cell growth and shows moderate effect in suppressing angiogenesis, displaying strong anti-ESCC effects in vitro and in vivo. Thus, AR-42 deserves further evaluation as a potential candidate for ESCC therapy.

Veliparib overcomes multidrug resistance in liver cancer cells

Overexpression of ATP-binding cassette (ABC) transporter is one of the most important factors taking responsibility for the progress of multidrug resistance (MDR) in multiple cancers. In this study, we investigated that veliparib, a PARP inhibitor which is in clinical development, could overcome ABCB1-mediated MDR in liver cancer cells. Veliparib could significantly enhance the cytotoxic effects of a series of conventional chemotherapeutic drugs in ABCB1-overexpression liver cancer cells. Mechanism study showed that veliparib could significantly enhance the accumulation of doxorubicin in ABCB1-overexpression liver cancer cells, without down-regulating the expression level of ABCB1. Finally, veliparib could significantly inhibit the ATPase activity of ABCB1 transporter. This study could provide information that combine veliparib with other chemotherapeutic drugs may benefit liver cancer patients.

Inhibition of Hepatic CYP2D6 by the Active N-Oxide Metabolite of Sorafenib

The multikinase inhibitor sorafenib (SOR) is used to treat patients with hepatocellular and renal carcinomas. SOR undergoes CYP-mediated biotransformation to a pharmacologically active N-oxide metabolite (SNO) that has been shown to accumulate to varying extents in individuals. Kinase inhibitors like SOR are frequently coadministered with a range of other drugs to improve the efficacy of anticancer drug therapy and to treat comorbidities. Recent evidence has suggested that SNO is more effective than SOR as an inhibitor of CYP3A4-mediated midazolam 1'-hydroxylation. CYP2D6 is also reportedly inhibited by SOR. The present study assessed the possibility that SNO might contribute to CYP2D6 inhibition. The inhibition kinetics of CYP2D6-mediated dextromethorphan O-demethylation were analyzed in human hepatic microsomes, with SNO found to be ~ 19-fold more active than SOR (K_is 1.8 ± 0.3 μM and 34 ± 11 μM, respectively). Molecular docking studies of SOR and SNO were undertaken using multiple crystal structures of CYP2D6. Both molecules mediated interactions with key amino acid residues in putative substrate recognition sites of CYP2D6. However, a larger number of H-bonding interactions was noted between the N-oxide moiety of SNO and active site residues that account for its greater inhibition potency. These findings suggest that SNO has the potential to contribute to pharmacokinetic interactions involving SOR, perhaps in those individuals in whom SNO accumulates.

Histone Deacetylase Expressions in Hepatocellular Carcinoma and Functional Effects of Histone Deacetylase Inhibitors on Liver Cancer Cells In Vitro

Hepatocellular carcinoma (HCC) is a leading cause for deaths worldwide. Histone deacetylase (HDAC) inhibition (HDACi) is emerging as a promising therapeutic strategy. However, most pharmacological HDACi unselectively block different HDAC classes and their molecular mechanisms of action are only incompletely understood. The aim of this study was to systematically analyze expressions of different HDAC classes in HCC cells and tissues and to functionally analyze the effect of the HDACi suberanilohydroxamic acid (SAHA) and trichostatin A (TSA) on the tumorigenicity of HCC cells. The gene expression of all HDAC classes was significantly increased in human HCC cell lines (Hep3B, HepG2, PLC, HuH7) compared to primary human hepatocytes (PHH). The analysis of HCC patient data showed the increased expression of several HDACs in HCC tissues compared to non-tumorous liver. However, there was no unified picture of regulation in three different HCC patient datasets and we observed a strong variation in the gene expression of different HDACs in tumorous as well as non-tumorous liver. Still, there was a strong correlation in the expression of HDAC class IIa (HDAC4, 5, 7, 9) as well as HDAC2 and 8 (class I) and HDAC10 (class IIb) and HDAC11 (class IV) in HCC tissues of individual patients. This might indicate a common mechanism of the regulation of these HDACs in HCC. The Cancer Genome Atlas (TCGA) dataset analysis revealed that HDAC4, HDAC7 and HDAC9 as well as HDAC class I members HDAC1 and HDAC2 is significantly correlated with patient survival. Furthermore, we observed that SAHA and TSA reduced the proliferation, clonogenicity and migratory potential of HCC cells. SAHA but not TSA induced features of senescence in HCC cells. Additionally, HDACi enhanced the efficacy of sorafenib in killing sorafenib-susceptible cells. Moreover, HDACi reestablished sorafenib sensitivity in resistant HCC cells. In summary, HDACs are significantly but differently increased in HCC, which may be exploited to develop more targeted therapeutic approaches. HDACi affect different facets of the tumorigenicity of HCC cells and appears to be a promising therapeutic approach alone or in combination with sorafenib.