Stellate cells and the development of liver cancer: therapeutic potential of targeting the stroma

NETosis in tumour microenvironment of liver: From primary to metastatic hepatic carcinoma

BACKGROUND

Hepatocellular carcinoma is a common and highly lethal tumour. The tumour microenvironment (TME) plays an important role in the progression and metastasis of hepatocellular carcinoma (HCC). A cell death mechanism, termed NETosis, has been found to play an important role in the TME of HCC.

SUMMARY

This review article focuses on the role of NETosis in the TME of HCC, a novel form of cell death in which neutrophils capture and kill microorganisms by releasing a type of DNA meshwork fibres called "NETs". This process is associated with neutrophil activation, local inflammation and cytokines. The study suggests that NETs play a multifaceted role in the development and metastasis of HCC. The article also discusses the role of NETs in tumour proliferation and metastasis, epithelial-mesenchymal transition (EMT), and surgical stress. In addition, the article discusses the interaction of NETosis with other immune cells in the TME and related therapeutic strategies. A deeper understanding of NETosis can help us better understand the complexity of the immune system and provide a new therapeutic basis for the treatment and prevention of HCC.

KEY INFORMATION

In conclusion, NETosis is important in the TME of liver. NETs have been shown to contribute to the progression and metastasis of liver cancer. The interaction between NETosis and immune cells in the TME, as well as related therapies, are important areas of research.

Lipopolysaccharide modification enhances the inhibitory effect of clodronate liposomes on hepatic fibrosis by depletion of macrophages and hepatic stellate cells

Hepatic fibrosis is a complex chronic liver disease in which both macrophages and hepatic stellate cells (HSCs) play important roles. Many studies have shown that clodronate liposomes (CLD-lipos) effectively deplete macrophages. However, no liposomes have been developed that target both HSCs and macrophages. This study aimed to evaluate the therapeutic efficacy of lipopolysaccharide-coupled clodronate liposomes (LPS-CLD-lipos) and the effects of liposomes size on hepatic fibrosis. Three rat models of hepatic fibrosis were established in vivo; diethylnitrosamine (DEN), bile duct ligation (BDL), and carbon tetrachloride (CCl4). Hematoxylin and eosin staining and serological liver function indices were used to analyze pathological liver damage. Masson's trichrome and Sirius red staining were used to evaluate the effect of liposomes on liver collagen fibers. The hydroxyproline content in liver tissues was determined. In vitro cell counting kit-8 (CCK-8) and immunofluorescence assays were used to further explore the effects of LPS modification and liposomes size on the killing of macrophages and HSCs. Both in vitro and in vivo experiments showed that 200 nm LPS-CLD-lipos significantly inhibited hepatic fibrosis and the abnormal deposition of collagen fibers in the liver and improved the related indicators of liver function. Further results showed that 200 nm LPS-CLD-lipos increased the clearance of macrophages and induced apoptosis of hepatic stellate cells, significantly. The present study demonstrated that 200 nm LPS-CLD-lipos could significantly inhibit hepatic fibrosis and improve liver function-related indices and this study may provide novel ideas and directions for hepatic fibrosis treatment.

Neoadjuvant and adjuvant therapy for biliary tract cancer: Advances and limitations

Biliary tract cancers (BTC) are a rare and aggressive consortium of malignancies, consisting of intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, and gallbladder carcinoma. While most patients present with metastatic disease, a minority of patients with BTC are eligible for curative surgical resection at the time of presentation. However, these patients have poor 5-year overall survival rates and high rates of recurrence, necessitating the improvement of the neoadjuvant and adjuvant treatment of BTC. In this review, we assess the neoadjuvant and adjuvant clinical trials for the treatment of BTC and discuss the challenges and limitations of clinical trials, as well as future directions for the treatment of BTC.

Dynamic regulation of EXO1 promotes the progression from liver fibrosis to HCC through TGF-β1/Smad signaling feedback loop

BACKGROUND

HSCs are the main stromal cells in the process of liver fibrosis and accelerate HCC progression. Previous studies determined that highly expressed exonuclease 1 (EXO1) increases the malignant behavior of HCC cells and is closely related to liver cirrhosis. This study aimed to explore the roles and mechanisms of EXO1 in the development of liver cirrhosis and HCC.

METHODS

We fully demonstrated that EXO1 expression was positively correlated with liver fibrosis and cirrhotic HCC by combining bioinformatics, hepatic fibrosis mouse models, and human HCC tissues. The role of EXO1 in a murine HCC model induced by activated forms of AKT and Ras oncogenes (AKT/Ras) was investigated by employing an adeno-associated virus-mediated EXO1 knockdown technique.

RESULTS

The knockdown of EXO1 promoted a regression of HCC in AKT/Ras mice and reduced the degree of liver fibrosis. Downregulated EXO1 inhibited LX-2 cell activation and inhibited the proliferation and migration of HCC cells. Moreover, conditioned medium of LX-2 cells with EXO1 overexpression increased the proliferation and migration of HCC cells, which was attenuated after EXO1 knockout in LX-2 cells. EXO1 knockdown attenuated the role of LX-2 in promoting HepG2 xenograft growth in vivo. Mechanistically, EXO1 promotes the activation of the downstream TGF-β-smad2/3 signaling in LX-2 and HCC cells. Interestingly, increased TGF-β-smad2/3 signaling had a feedback effect on EXO1, which sustains EXO1 expression and continuously stimulates the activation of HSCs.

CONCLUSIONS

EXO1 forms a positive feedback circuit with TGF-β-Smad2/3 signaling and promotes the activation of HSCs, which accelerates HCC progression. Those findings indicate EXO1 may be a promising target for the diagnosis and treatment of cirrhotic HCC.

Discovery of dual-target natural inhibitors of meprins α and β metalloproteases for inflammation regulation: pharmacophore modelling, molecular docking, ADME prediction, and molecular dynamics studies

Meprins, zinc-dependent metalloproteinases belonging to the metzincin family, have been associated with various inflammatory diseases due to their abnormal expression and activity. In this study, we utilized pharmacophore modelling to identify crucial features for discovering potential dual inhibitors targeting meprins α and β. We screened four pharmacophoric features against a library of 270,540 natural compounds from the Zinc database, resulting in 84,092 matching compounds. Molecular docking was then performed on these compounds, targeting the active sites of meprins α and β. Docking results revealed six compounds capable of interacting with both isoforms, with binding affinities ranging from -10.0 to -10.5 kcal/mol and -6.9 to -9.9 kcal/mol for meprin α and β, respectively. Among these compounds, ZINC000008790788 and ZINC000095099469 displayed superior docking scores and MM-GBSA binding free energy compared to reference ligands. Furthermore, these two compounds exhibited acceptable predicted pharmacokinetic properties and stable interactions with meprins α and β during molecular dynamics simulations. This study presents a comprehensive approach for identifying potential dual inhibitors of meprin α and β, offering insights into the development of therapeutic interventions for inflammatory diseases associated with meprin dysregulation.

Loss of Krüppel-like factor-10 facilitates the development of chemical-induced liver cancer in mice

BACKGROUND

Krüppel-like factor 10 (KLF10) is involved in a positive feedback loop that regulates transforming growth factor β (TGFβ) signaling, and TGFβ plays an important role in the pathogenesis of liver disease. Here, we investigated whether KLF10 deletion affects the development of liver fibrosis and hepatocellular carcinoma (HCC).

METHODS

We induced KLF10 deletion in C57BL/6 mice. Liver fibrosis was induced by feeding a diet high in fat and sucrose (high-fat diet [HFD]), whereas HCC was produced by intraperitoneal administration of N-diethylnitrosamine (DEN). An in vitro experiment was performed to evaluate the role of KLF10 in the cancer microenvironment using Hep3B and LX2 cells. An immunohistochemical study of KLF10 expression was performed using human HCC samples from 60 patients who had undergone liver resection.

RESULTS

KLF10 deletion resulted in an increased DEN-induced HCC burden with significant upregulation of SMAD2, although loss of KLF10 did not alter HFD-induced liver fibrosis. DEN-treated mice with KLF10 deletion exhibited increased levels of mesenchymal markers (N-cadherin and SNAI2) and tumor metastasis markers (matrix metalloproteinases 2 and 9). KLF10 depletion in Hep3B and LX2 cells using siRNA was associated with increased invasiveness. Compared with co-culture of KLF10-preserved Hep3B cells and KLF10-intact LX2 cells, co-culture of KLF10-preserved Hep3B cells and KLF10-depleted LX2 cells resulted in significantly enhanced invasion. Low KLF10 expression in resected human HCC specimens was associated with poor survival.

CONCLUSION

The results of this study suggest that loss of KLF10 facilitates liver cancer development with alteration in TGFβ signaling.

Targeting immune checkpoints on tumor-associated macrophages in tumor immunotherapy

Unprecedented breakthroughs have been made in cancer immunotherapy in recent years. Particularly immune checkpoint inhibitors have fostered hope for patients with cancer. However, immunotherapy still exhibits certain limitations, such as a low response rate, limited efficacy in certain populations, and adverse events in certain tumors. Therefore, exploring strategies that can improve clinical response rates in patients is crucial. Tumor-associated macrophages (TAMs) are the predominant immune cells that infiltrate the tumor microenvironment and express a variety of immune checkpoints that impact immune functions. Mounting evidence indicates that immune checkpoints in TAMs are closely associated with the prognosis of patients with tumors receiving immunotherapy. This review centers on the regulatory mechanisms governing immune checkpoint expression in macrophages and strategies aimed at improving immune checkpoint therapies. Our review provides insights into potential therapeutic targets to improve the efficacy of immune checkpoint blockade and key clues to developing novel tumor immunotherapies.

High producer variant of lipoprotein lipase may protect from hepatocellular carcinoma in alcohol-associated cirrhosis

Background & Aims

Progression of alcohol-associated liver disease (ALD) is driven by genetic predisposition. The rs13702 variant in the lipoprotein lipase (LPL) gene is linked to non-alcoholic fatty liver disease. We aimed at clarifying its role in ALD.

Methods

Patients with alcohol-associated cirrhosis, with (n = 385) and without hepatocellular carcinoma (HCC) (n = 656), with HCC attributable to viral hepatitis C (n = 280), controls with alcohol abuse without liver damage (n = 366), and healthy controls (n = 277) were genotyped regarding the LPL rs13702 polymorphism. Furthermore, the UK Biobank cohort was analysed. LPL expression was investigated in human liver specimens and in liver cell lines.

Results

Frequency of the LPL rs13702 CC genotype was lower in ALD with HCC in comparison to ALD without HCC both in the initial (3.9% vs. 9.3%) and the validation cohort (4.7% vs. 9.5%; p <0.05 each) and compared with patients with viral HCC (11.4%), alcohol misuse without cirrhosis (8.7%), or healthy controls (9.0%). This protective effect (odds ratio [OR] = 0.5) was confirmed in multivariate analysis including age (OR = 1.1/year), male sex (OR = 3.0), diabetes (OR = 1.8), and carriage of the PNPLA3 I148M risk variant (OR = 2.0). In the UK Biobank cohort, the LPL rs13702 C allele was replicated as a risk factor for HCC. Liver expression of LPL mRNA was dependent on LPL rs13702 genotype and significantly higher in patients with ALD cirrhosis compared with controls and alcohol-associated HCC. Although hepatocyte cell lines showed negligible LPL protein expression, hepatic stellate cells and liver sinusoidal endothelial cells expressed LPL.

Conclusions

LPL is upregulated in the liver of patients with alcohol-associated cirrhosis. The LPL rs13702 high producer variant confers protection against HCC in ALD, which might help to stratify people for HCC risk.

Impact and implications

Hepatocellular carcinoma is a severe complication of liver cirrhosis influenced by genetic predisposition. We found that a genetic variant in the gene encoding lipoprotein lipase reduces the risk for hepatocellular carcinoma in alcohol-associated cirrhosis. This genetic variation may directly affect the liver, because, unlike in healthy adult liver, lipoprotein lipase is produced from liver cells in alcohol-associated cirrhosis.

Enhanced glypican-3-targeted identification of hepatocellular carcinoma with liver fibrosis by pre-degrading excess fibrotic collagen

Most hepatocellular carcinomas (HCCs) occur in cirrhotic livers, but unequivocal diagnosis of early HCC from the fibrotic microenvironment remains a formidable challenge with conventional imaging strategies, mainly because of the massive fibrotic collagen deposition leading to hepatic nodules formation and dysfunction of contrast agent metabolism. Here, we developed a "sweep-and-illuminate" imaging strategy, pre-degrade hepatic fibrotic collagen with collagenase I conjugated human serum albumin (HSA-C) and then targeting visualize HCC lesion with GPC3 targeting nanoparticles (TSI NPs, TJ2 peptide-superparamagnetic iron oxide-indocyanine green) via fluorescence imaging (FLI) and magnetic particle imaging (MPI). TSI NPs delineated a clear boundary of HCC and normal liver, and the tumor-to-background ratios (TBRs) detected by FLI and MPI were 5.43- and 1.34-fold higher than the non-targeted group, respectively. HSA-C could degrade 24.7% fibrotic collagen, followed by 27.2% reduction of nonspecific NPs retention in mice with liver fibrosis. In a pathological state in which HCC occurs in the fibrotic microenvironment, HSA-C-mediated pre-degradation of fibrotic collagen reduced background signal interference in fibrotic tissues and enhanced the intratumoral uptake of TSI NPs, resulting in the clear demarcation between HCC and liver fibrosis, and the TBR was increased 2.61-fold compared to the group without HSA-C pretreatment. We demonstrated the feasibility of combined pre-degradation of fibrotic collagen and application of a GPC3-targeted FLI/MPI contrast agent for early HCC identification, as well as its clinical value in the management of patients with advanced liver fibrosis. STATEMENT OF SIGNIFICANCE: Given that liver fibrosis hinders early detection and treatment options of hepatocellular carcinomas (HCCs), we report a "sweep-and-illuminate" imaging strategy to enhance the efficiency of HCC identification by modulating the irreversible liver fibrosis. We first "sweep" nonspecific interference of contrast agent by pre-degrading fibrotic collagen with human serum albumin-carried collagenase I (HSA-C); and then specifically "illuminate" HCC lesions with GPC3-targeted-SPIO-ICG nanoparticles (TSI NPs). HSA-C can degrade 24.7% fibrotic collagen, followed by 27.2% reduction of nonspecific NPs retention in mice with liver fibrosis. Furthermore, in HCC models coexisting with liver fibrosis, the combined application of HSA-C and TSI NPs can clarify the demarcation between HCC and liver fibrosis with a 2.61-fold increase in the tumor-to-background ratio. This study may expand the potential of combinatorial biomaterials for early HCC diagnosis.

Non-Parenchymal Cells and the Extracellular Matrix in Hepatocellular Carcinoma in Non-Alcoholic Fatty Liver Disease

Hepatocellular carcinoma (HCC) in the setting of non-alcoholic fatty liver disease (NAFLD)-related cirrhosis and even in the pre-cirrhotic state is increasing in incidence. NAFLD-related HCC has a poor clinical outcome as it is often advanced at diagnosis due to late diagnosis and systemic treatment response is poor due to reduced immune surveillance. Much of the focus of molecular research has been on the pathological changes in hepatocytes; however, immune cells, hepatic stellate cells, liver sinusoidal endothelial cells and the extracellular matrix may play important roles in the pathogenesis of NAFLD-related HCC as well. Here, we review the role of non-parenchymal cells in the liver in the pathogenesis of HCC in the context of NAFLD-NASH, with a particular focus on the innate and the adaptive immune system, fibrogenesis and angiogenesis. We review the key roles of macrophages, hepatic stellate cells (HSCs), T cells, natural killer (NK) cells, NKT cells and liver sinusoidal endothelial cells (LSECs) and the role of the extracellular matrix in hepatocarcinogenesis within the steatotic milieu.

Cancer Stem Cell and Hepatic Stellate Cells in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common liver cancer. It is highly lethal and has high recurrence. Death among HCC patients occur mainly due to tumor progression, recurrence, metastasis, and chemoresistance. Cancer stem cells (CSCs) are cell subpopulations within the tumor that promote invasion, recurrence, metastasis, and drug resistance. Hepatic stellate cells (HSCs) are important components of the tumor microenvironment (TME) responsible for primary secretory ECM proteins during liver injury and inflammation. These cells promote fibrogenesis, infiltrate the tumor stroma, and contribute to HCC development. Interactions between HSC and CSC and their microenvironment help promote carcinogenesis through different mechanisms. This review summarizes the roles of CSCs and HSCs in establishing the TME in primary liver tumors and describes their involvement in HCC chemoresistance.

Intercellular communication among liver cells in the perisinusoidal space of the injured liver: Pathophysiology and therapeutic directions

Hepatic stellate cells (HSCs) in the perisinusoidal space are surrounded by hepatocytes, liver sinusoidal endothelial cells, Kupffer cells, and other resident immune cells. In the normal liver, HSCs communicate with these cells to maintain normal liver functions. However, after chronic liver injury, injured hepatocytes release several proinflammatory mediators, reactive oxygen species, and damage-associated molecular patterns into the perisinusoidal space. Consequently, such alteration activates quiescent HSCs to acquire a myofibroblast-like phenotype and express high amounts of transforming growth factor-β1, angiopoietins, vascular endothelial growth factors, interleukins 6 and 8, fibril forming collagens, laminin, and E-cadherin. These phenotypic and functional transdifferentiation lead to hepatic fibrosis with a typical abnormal extracellular matrix synthesis and disorganization of the perisinusoidal space of the injured liver. Those changes provide a favorable environment that regulates tumor cell proliferation, migration, adhesion, and survival in the perisinusoidal space. Such tumor cells by releasing transforming growth factor-β1 and other cytokines, will, in turn, activate and deeply interact with HSCs via a bidirectional loop. Furthermore, hepatocellular carcinoma-derived mediators convert HSCs and macrophages into protumorigenic cell populations. Thus, the perisinusoidal space serves as a critical hub for activating HSCs and their interactions with other cell types, which cause a variety of liver diseases such as hepatic inflammation, fibrosis, cirrhosis, and their complications, such as portal hypertension and hepatocellular carcinoma. Therefore, targeting the crosstalk between activated HSCs and tumor cells/immune cells in the tumor microenvironment may also support a promising therapeutic strategy.

Potential tumor marker for hepatocellular carcinoma identification: PI3K and pro-inflammatory cytokines (TGF-β, IL-1, and IL-6)

OBJECTIVES

Hepatocellular carcinoma (HCC), the most common form of liver cancer, is a leading cause of tumor-associated mortality worldwide. Diagnosis based upon non-invasive criteria is currently challenged by the need for molecular information that requires tissue or liquid biopsies. The progression of HCC is often associated with chronic inflammation, expression levels of inflammatory mediators, chemokine, and cytokines. In this study, we try to evaluate the PI3K and pro-inflammatory cytokines, TGF-β, IL-1, and IL-6 expression level in patients with liver cancer.

MATERIALS AND METHODS

The kupffer cells were isolated from patient's specimens. Real-time PCR was applied to evaluate the expression level of PI3K in cell lines or tumors. The concentrations of TGF-β, IL-1, and IL-6 were measured by the quantitative ELISA kit.

RESULTS

PI3K mRNA expression in cancer cells was increased markedly vs. normal cells. The ELISA results demonstrated over expression of TGF-β, IL-1, and IL-6 in patients and positive correlation between tumor size and stage.

DISCUSSION

This study suggests that targeting the expression level of PI3K and pro-inflammatory chemokine and cytokines, TGF-β, IL-1, and IL-6, may be a potential diagnostic strategy in HCC patients.

Tumor Microenvironment in Hepatocellular Carcinoma: Key Players for Immunotherapy

Hepatocellular carcinoma (HCC) remains a serious medical therapeutic challenge as conventional curative avenues such as surgery and chemotherapy only benefit for few patients with limited tumor burden. Immunotherapy achieves clinical progress in the treatment of this prevalent malignant disease by virtue of the development of tumor immunology; however, most patients have experienced minimal or no clinical benefit in terms of overall survival. The complexity and diversity of tumor microenvironment (TME) built by immune and stromal cell subsets has been considered to be responsible for the insufficiency of immunotherapy. The advance of bioanalytical technology boosts the exploration of the composition and differentiation of these infiltrated cells, which reflect the immune state of the TME and impact the efficacy of the antitumor immune response. Targeting these cells to remodel the TME is one of the important immunotherapeutic approaches to improve HCC treatment. In this review, we focused on the role of these non-cancerous cells in the tumor progression, and elaborated their function on cancer immunotherapy when manipulating them as potential targets.

Function of gaseous hydrogen sulfide in liver fibrosis

Over the past few years, hydrogen sulfide (H₂S) has been shown to exert several biological functions in mammalian. The endogenous production of H₂S is mainly mediated by cystathione β-synthase, cystathione γ-lyase and 3-mercaptopyruvate sulfur transferase. These enzymes are broadly expressed in liver tissue and regulates liver function by working on a variety of molecular targets. As an important regulator of liver function, H₂S is critically involved in the pathogenesis of various liver diseases, such as non-alcoholic steatohepatitis and liver cancer. Targeting H₂S-generating enzymes may be a therapeutic strategy for controlling liver diseases. This review described the function of H₂S in liver disease and summarized recent characterized role of H₂S in several cellular process of the liver.

Neurotrophic factors stimulate the activation of hepatic stellate cells in liver fibrosis

BACKGROUND AND AIMS

Patients with liver fibrosis who have pain in the liver region may have changed nerve factors. The expression of neurokines and hepatic nerves in liver fibrosis, however, was little understood. In order to better understand how liver fibrosis develops, we plan to look into the hepatic nerve and neurokine changes and how they relate to hepatic stellate cells (HSCs).

METHODS

The expression of neurokines in liver samples from 55 chronic hepatitis B patients and the carbon tetrachloride (CCl₄) animal model were studied. The co-staining of Nissl and α-SMA allowed us to investigate the neurons and their interaction with α-SMA in fibrotic livers, as well as the expression of the glial cell marker glial fibrillary acidic protein (GFAP) and its relationship with α-SMA, a marker of HSCs. SH-SY5Y cells were treated with a fibrotic serum to imitate the hepatic microenvironment on neuronal cells. We also used brain-derived neurotrophic factor (BDNF) to stimulate mouse primary HSCs and LX2.

RESULTS

The levels of mRNA for neurokines such as BDNF, GFAP, and growth-associated protein (GAP43) are significantly increased in both human and animal liver fibrosis. As liver fibrosis advances, we found that Nissl bodies and α-SMA may co-localize, suggesting a connection between hepatic nerves and HSCs. Human fibrotic serum may increase neurkines, notably BDNF, in SH-SY5Y cells. We also found that BDNF increased pro-inflammatory cytokines and fibrogenic markers in hHSCs.

CONCLUSIONS

Patients with hepatic fibrosis had significantly higher levels of BDNF, GFAP, GAP43, and nerve fibers. HSC and nerve fibers interact, and nerves also create neurogenic substances that promote liver fibrosis and HSC activation.

Hepatic Stellate Cell Modulates the Immune Microenvironment in the Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a major cause of increases in the mortality rate due to cancer that usually develops in patients with liver fibrosis and impaired hepatic immunity. Hepatic stellate cells (HSCs) may directly or indirectly crosstalk with various hepatic cells and subsequently modulate extracellular remodeling, cell invasion, macrophage conversion, and cancer deterioration. In this regard, the tumor microenvironment created by activated HSC plays a critical role in mediating pathogenesis and immune escape during HCC progression. Herein, intermediately differentiated human liver cancer cell line (J5) cells were co-cultured with HSC-conditioned medium (HSC-CM); changes in cell phenotype and cytokine profiles were analyzed to assess the impact of HSCs on the development of hepatoma. The stage of liver fibrosis correlated significantly with tumor grade, and the administration of conditioned medium secreted by activated HSC (aHSC-CM) could induce the expression of N-cadherin, cell migration, and invasive potential, as well as the activity of matrix metalloproteinases in J5 cells, implying that aHSC-CM could trigger the epithelial-mesenchymal transition (EMT). Next, the HSC-CM was further investigated and network analysis indicated that specific cytokines and soluble proteins, such as activin A, released from activated HSCs could remarkably affect the tumor-associated immune microenvironment involved in macrophage polarization, which would, in turn, diminish a host’s immune surveillance and drive hepatoma cells into a more malignant phenotype. Together, our findings provide a novel insight into the integral roles of HSCs to enhance hepatocarcinogenesis through their immune-modulatory properties and suggest that HSC may serve as a potent target for the treatment of advanced HCC.

Small Molecule Inhibitors for Hepatocellular Carcinoma: Advances and Challenges

According to data provided by World Health Organization, hepatocellular carcinoma (HCC) is the sixth most common cause of deaths due to cancer worldwide. Tremendous progress has been achieved over the last 10 years developing novel agents for HCC treatment, including small-molecule kinase inhibitors. Several small molecule inhibitors currently form the core of HCC treatment due to their versatility since they would be more easily absorbed and have higher oral bioavailability, thus easier to formulate and administer to patients. In addition, they can be altered structurally to have greater volumes of distribution, allowing them to block extravascular molecular targets and to accumulate in a high concentration in the tumor microenvironment. Moreover, they can be designed to have shortened half-lives to control for immune-related adverse events. Most importantly, they would spare patients, healthcare institutions, and society as a whole from the burden of high drug costs. The present review provides an overview of the pharmaceutical compounds that are licensed for HCC treatment and other emerging compounds that are still investigated in preclinical and clinical trials. These molecules are targeting different molecular targets and pathways that are proven to be involved in the pathogenesis of the disease.

Three-dimensional (3D) cell culture: a valuable step in advancing treatments for human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignant cancer and the third most frequent cause of tumour-related mortality worldwide. Currently, several surgical and medical therapeutic strategies are available for HCCs; however, the interaction between neoplastic cells and non-neoplastic stromal cells within the tumour microenvironment (TME) results in strong therapeutic resistance of HCCs to conventional treatment. Therefore, the development of novel treatments is urgently needed to improve the survival of patients with HCC. The first step in developing efficient chemotherapeutic drugs is the establishment of an appropriate system for studying complex tumour culture and microenvironment interactions. Three-dimensional (3D) culture model might be a crucial bridge between in vivo and in vitro due to its ability to mimic the naturally complicated in vivo TME compared to conventional two-dimensional (2D) cultures. In this review, we shed light on various established 3D culture models of HCC and their role in the investigation of tumour-TME interactions and HCC-related therapeutic resistance.

Comparisons of Quantitative Parameters of Ga-68-Labelled Fibroblast Activating Protein Inhibitor (FAPI) PET/CT and [18F]F-FDG PET/CT in Patients with Liver Malignancies

Purpose

To compare quantitative parameters and tumour detection rates of [⁶⁸ Ga]Ga-FAPI PET/CT with those of dedicated liver PET/MRI and ¹⁸F-FDG PET in patients with liver malignancies.

Procedures

Twenty-seven patients (29 imaging studies) with diagnosed or suspected liver malignancies who underwent [⁶⁸ Ga]Ga-FAPI-46 PET/CT, liver PET/MRI, and [¹⁸F]FDG PET/CT between September 2020 and June 2021 were retrospectively analysed. MRI findings were used as the reference standard for diagnosis.

Results

The 27 patients had a median age of 68 years (interquartile range: 60–74 years; 21 men). Primary intrahepatic tumours were reported in 13 patients (15 imaging studies) with cholangiocarcinoma (CCA) and in 14 patients with hepatocellular carcinoma (HCC). All intrahepatic lesions detectable on MRI were also detected on [⁶⁸ Ga]Ga-FAPI-46 PET/CT giving a sensitivity of 100% (19/19), whereas the sensitivity of [¹⁸F]FDG PET/CT was 58% (11/19). All intrahepatic lesions were detected on [⁶⁸ Ga]Ga-FAPI-46 PET/CT, on which they showed higher activity (median SUVmax: 15.61 vs. 5.17; P < .001) and higher target-to-background ratio (TBR; median, 15.90 vs. 1.69, P < .001) than on [¹⁸F]FDG, especially in patients with CCA (median TBR, 21.08 vs. 1.47, respectively; P < .001). The uptake positivity rate in regional node metastasis was 100% (12/12) on [⁶⁸ Ga]Ga-FAPI-46 PET/CT compared with 58% (7/12) on [¹⁸F]FDG PET/CT. All patients with distant metastasis (100%, 14/14) were detected on both [¹⁸F]FDG and [⁶⁸ Ga]Ga-FAPI-46 PET/CT imaging, although more distant metastatic lesions were detected on [⁶⁸ Ga]Ga-FAPI-46 PET/CT than on [¹⁸F]FDG (96% (42/44) vs. 89% (39/44), respectively).

Conclusion

[⁶⁸ Ga]Ga-FAPI PET/CT with dedicated liver PET/MRI shows potential for superior detection of hepatic malignancy compared with [¹⁸F]FDG PET/CT or MRI alone.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11307-022-01732-2.

β-arrestin2 regulating β2-adrenergic receptor signaling in hepatic stellate cells contributes to hepatocellular carcinoma progression

Background: β-arrestin2 and β2-adrenergic receptor (β2-AR) have important roles in malignant tumors, the present study aims to investigate the role of activated β2-AR in hepatic stellate cells (HSCs) during hepatocellular carcinoma (HCC) progression and the regulatory effect of β-arrestin2.

Methods: Immunofluorescence and Western blot were used to detect the expression of β-arrestin2 and β2-AR in HSCs of liver tissues from human HCC samples and diethylnitrosamine (DEN)-induced HCC model mice. We next used β-arrestin2^-/- mice to demonstrate the regulatory role of β-arrestin2 in DEN mice. The subsets of T cells were quantified by flow cytometry. MTT and wound healing assay were applied to detect the proliferation and migration of cells. Co-immunoprecipitation assay was used to detect the link of β-arrestin2 and β2-AR in HSCs. Effect of β-arrestin2 overexpression on β2-AR downstream signaling pathway was verified by Western blot. The secretion of CCL2 was detected by ELISA.

Results: The expression of β2-AR was significantly increased, while β-arrestin2 was decreased in HSCs of HCC tissues. And β-arrestin2 deficiency exacerbates DEN-induced HCC accompanied with increased β2-AR expression. The results of flow cytometry showed that the percentage of activated T cells decreased gradually after DEN injection. β-arrestin2 knockout down-regulated the ratio of activated T cells. In vitro, selective activation of β2-AR in HSCs promoted the proliferation and migration of HCC cells. β-arrestin2 overexpression enhanced co-immunoprecipitation of β-arrestin2 and β2-AR in activated HSCs, and decreased its downstream Akt phosphorylation. Akt inhibitor decreased secretion of CCL2 in activated HSCs.

Conclusion: Our study demonstrated that β2-AR activation in HSCs induces the proliferation and migration of HCC cells may be through Akt signaling, and this effect appears to be regulated by β-arrestin2.

Three-Dimensional Cell Culture Models of Hepatocellular Carcinoma - a Review

INTRODUCTION

Three-dimensional (3D) cell culture studies are becoming extremely common because of their capability to mimic tumor architecture, such as cell-cell and cell-ECM interactions, more efficiently than 2D monolayer systems. These interactions have important roles in defining the tumor cell behaviors, such as proliferation, differentiation, and most importantly, tumor drug response.

OBJECTIVE

This review aims to provide an overview of the methods for 3D tumor spheroid formation to model human tumors, specifically concentrated on studies using hepatocellular carcinoma (HCC) cells.

METHOD

We obtained information from previously published articles. In this review, there is discussion of the scaffold and non-scaffold-based approaches, including hanging drop, bioreactors and 3D bioprinting.

RESULTS AND CONCLUSION

The mimicking of the tumor microenvironment (TME) as tumor spheroids could provide a valuable platform for studying tumor biology. Multicellular tumor spheroids are self-assembled cultures of mixed cells (tumor and stromal cells) organized in a 3D arrangement. These spheroids closely mimic the main features of human solid tumors, such as structural organization, central hypoxia, and overall oxygen and nutrient gradients. Hepatocellular carcinoma (HCC) is the most common liver malignancy, and most difficult to overcome because of its drug resistance and tumor heterogeneity. In order to mimic this highly heterogeneous environment, 3D cell culture systems are needed.

Hepatitis B Virus Promotes Hepatocellular Carcinoma Progression Synergistically With Hepatic Stellate Cells via Facilitating the Expression and Secretion of ENPP2

Background: Hepatitis B virus (HBV) infection is a major risk factor causing hepatocellular carcinoma (HCC) development, but the molecular mechanisms are not fully elucidated. It has been reported that virus infection induces ectonucleotide pyrophosphatase-phosphodiesterase 2 (ENPP2) expression, the latter participates in tumor progression. Therefore, the aim of the present study was to investigate whether HBV induced HCC malignancy via ENPP2.

Methods: HCC patient clinical data were collected and prognosis was analyzed. Transient transfection and stable ectopic expression of the HBV genome were established in hepatoma cell lines. Immunohistochemical staining, RT-qPCR, western blot, and ELISA assays were used to detect the expression and secretion of ENPP2. Finally, CCK-8, colony formation, and migration assays as well as a subcutaneous xenograft mouse model were used to investigate the influence of HBV infection, ENPP2 expression, and activated hepatic stellate cells (aHSCs) on HCC progression in vitro and in vivo.

Results: The data from cancer databases indicated that the level of ENPP2 was significant higher in HCC compared within normal liver tissues. Clinical relevance analysis using 158 HCC patients displayed that ENPP2 expression was positively correlated with poor overall survival and disease-free survival. Statistical analysis revealed that compared to HBV-negative HCC tissues, HBV-positive tissues expressed a higher level of ENPP2. In vitro, HBV upregulated ENPP2 expression and secretion in hepatoma cells and promoted hepatoma cell proliferation, colony formation, and migration via enhancement of ENPP2; downregulation of ENPP2 expression or inhibition of its function suppressed HCC progression. In addition, aHSCs strengthened hepatoma cell proliferation, migration in vitro, and promoted tumorigenesis synergistically with HBV in vivo; a loss-function assay further verified that ENPP2 is essential for HBV/aHSC-induced HCC progression.

Conclusion: HBV enhanced the expression and secretion of ENPP2 in hepatoma cells, combined with aHSCs to promote HCC progression via ENPP2.

GJA1 promotes hepatocellular carcinoma progression by mediating TGF-β-induced activation and the epithelial-mesenchymal transition of hepatic stellate cells

Introduction

Gap junction protein, alpha 1 (GJA1), which is correlated with recurrences and unfavorable prognoses in hepatocellular carcinomas (HCCs), is one of the specific proteins expressed by activated hepatic stellate cells (HSCs).

Methods

Expression of GJA1 was compared between HCCs and nontumor tissues (NTs), between hepatic cirrhosis and NTs, and between primary and metastatic HCCs using transcriptomic datasets from the Gene Expression Omnibus and the Integrative Molecular Database of Hepatocellular Carcinoma. The in vitro activities of GJA1 were investigated in cultured HSCs and HCC cells. The underlying mechanism was characterized using Gene Set Enrichment Analysis and validated by western blotting.

Results

The expression of GJA1 was significantly increased in HCCs and hepatic cirrhosis compared to that in NTs. GJA1 was also overexpressed in pulmonary metastases from HCCs when compared with HCCs without metastasis. Overexpression of GJA1 promoted while knockdown of GJA1 inhibited proliferation and transforming growth factor (TGF)-β-mediated activation and migration of cultured HSCs. Overexpression of GJA1 by lentivirus infection promoted proliferation and migration, while conditioned medium from HSCs overexpressing GJA1 promoted migration but inhibited proliferation of Hep3B and PLC-PRF-5 cells. Lentivirus infection with shGJA1 or conditioned medium from shGJA1-infected HSCs inhibited the proliferation and migration of HCCLM3 cells that had a high propensity toward lung metastasis. Mechanistically, GJA1 induced the epithelial–mesenchymal transition (EMT) in HSCs and HCCLM3 cells.

Conclusion

GJA1 promoted HCC progression by inducing HSC activation and the EMT in HSCs. GJA1 is potentially regulated by TGF-β and thus may be a therapeutic target to inhibit HCC progression.

Multiple Roles of IL6 in Hepatic Injury, Steatosis, and Senescence Aggregate to Suppress Tumorigenesis

Hepatocellular carcinoma (HCC) typically develops on a background of chronic hepatitis for which the proinflammatory cytokine IL6 is conventionally considered a crucial driving factor. Paradoxically, IL6 also acts as a hepatoprotective factor in chronic liver injury. Here we used the multidrug-resistant gene 2 knockout (Mdr2-/-) mouse model to elucidate potential roles of IL6 in chronic hepatitis-associated liver cancer. Long-term analysis of three separate IL6/Stat3 signaling-deficient Mdr2-/- strains revealed aggravated liver injury with increased dysplastic nodule formation and significantly accelerated tumorigenesis in all strains. Tumorigenesis in the IL6/Stat3-perturbed models was strongly associated with enhanced macrophage accumulation and hepatosteatosis, phenotypes of nonalcoholic steatohepatitis (NASH), as well as with significant reductions in senescence and the senescence-associated secretory phenotype (SASP) accompanied by increased hepatocyte proliferation. These findings reveal a crucial suppressive role for IL6/Stat3 signaling in chronic hepatitis-associated hepatocarcinogenesis by impeding protumorigenic NASH-associated phenotypes and by reinforcing the antitumorigenic effects of the SASP. SIGNIFICANCE: These findings describe a context-dependent role of IL6 signaling in hepatocarcinogenesis and predict that increased IL6-neutralizing sgp130 levels in some patients with NASH may herald early HCC development.See related commentary by Huynh and Ernst, p. 4671.

Hepatic Stellate Cell: A Potential Target for Hepatocellular Carcinoma

Liver cancer is a leading cause of cancer-related death worldwide, in which hepatocellular carcinoma (HCC) accounts for the majority. Despite the progression in treatment, the prognosis remains extremely poor for HCC patients. The mechanisms of hepatocarcinogenesis are complex, of which fibrosis is acknowledged as the pre-cancerous stage of HCC. Approximately, 80-90% of HCC develops in the fibrotic or cirrhotic livers. Hepatic stellate cells (HSCs), the main effector cells of liver fibrosis, could secret various biological contents to maintain the liver inflammation. By decades, HSCs are increasingly correlated with HCC in the tumor microenvironment. In this review, we summarized the underlying mechanisms that HSCs participated in the genesis and progression of HCC. HSCs secrete various bioactive contents and regulate tumor-related pathways, subsequently contribute to metastasis, angiogenesis, immunosuppression, chemoresistance and cancer stemness. The study indicates that HSC plays vital roles in HCC progression, suggesting it as a promising therapeutic target for HCC treatment.

Decreased risk of liver and intrahepatic cancer in non-H. pylori-infected perforated peptic ulcer patients with truncal vagotomy: a nationwide study

The vagal nervous system is central to the physiological responses and systemic diseases of the liver. We evaluated the subsequent risk of liver and intrahepatic cancer (HCC/ICC) in non-H. pylori (HP)-infected perforated peptic ulcer (PPU) patients with and without vagotomy. Hospitalized PPU patients who underwent simple closure or truncal vagotomy/pyloroplasty (TVP) in the National Health Insurance Research Database from 2000 to 2008 were enrolled. The exclusion criteria included: (1) Multiple surgeries for PPU were received at the same admission; (2) Any cancer history; (3) Previous peptic ulcer-associated surgery; (4) HP infection history; (5) Viral hepatitis infection history; (6) Follow-up duration < 1 year; and (7) Age < 18 years. The risks of developing HCC/ICC in PPU patients with and without vagotomy were assessed at the end of 2013. To balance the baseline condition between groups, we used the propensity score matched method to select study subjects. Cox proportional hazard regression was used to estimate the hazard ratio and 95% confidence interval (CI) of HCC/ICC. Before propensity score matching, 675 simple suture patients and 54 TVP patients had HCC/ICC, which corresponded to incidences of 2.11 and 0.88 per 1000 person-years, respectively. After propensity score matching, 145 simple suture patients and 54 TVP patients experienced HCC/ICC, which corresponded to incidences of 1.45 and 0.88 per 1000 person-years, respectively. The TVP patients had a 0.71 (95% CI 0.54-0.95)- and 0.69 (95% CI 0.49-0.97)-fold risk of developing HCC/ICC compared to simple suture patients before and after propensity score matching. Our findings reported that, in the Asian population, TVP decreases the risk of HCC/ICC in non-HP-infected PPU patients compared to simple closure patients. However, further studies are warranted.

Periostin deficiency reduces diethylnitrosamine-induced liver cancer in mice by decreasing hepatic stellate cell activation and cancer cell proliferation

Periostin is a critical extracellular regulator in the pathogenesis of liver disorders such as hepatosteatosis, non-alcoholic steatohepatitis, inflammation, and fibrosis. Periostin is also involved in the progression of hepatocellular carcinoma (HCC). However, the molecular mechanisms of periostin in hepatic stellate cell (HSC) activation and tumor cell proliferation in the pathogenesis of HCC remain largely unknown. We demonstrate that periostin is markedly upregulated in diethylnitrosamine (DEN)-induced mouse HCC tissues and that periostin knockout impairs DEN-induced HCC development. Periostin is predominantly derived from activated HSCs and periostin deficiency in HSCs impairs HSC activation and inhibits HSC-promoted HCC cell proliferation in vitro and tumor growth in vivo. Mechanistically, periostin promotes HSC activation through the integrin-FAK-STAT3-periostin pathway and augments HCC cell proliferation by activating ERK. There are positive correlations between periostin and HSC activation and cell proliferation in HCC clinical samples. Collectively, our findings demonstrate that HSC-derived periostin promotes HCC development by enhancing HSC activation through an autocrine periostin-integrin-FAK-STAT3-periostin circuit and by augmenting HCC cell proliferation via the ERK pathway in a paracrine manner. Thus, periostin is a multifaceted extracellular regulator in the development of HCC. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Liver stiffness assessed by shear-wave elastography declines in parallel with immunoregulatory proteins in patients with chronic HCV infection during DAA therapy

BACKGROUND

A rapid decline of liver stiffness (LS) was detected by non-invasive methods in patients with chronic hepatitis C (HCV) infection during treatment with direct-acting antivirals (DAA).

OBJECTIVE

To investigate the influence of inflammation on LS.

METHODS

We prospectively examined LS by sonographic shear-wave elastography in 217 patients during DAA therapy from treatment initiation (BL) to 12 weeks after end of therapy (SVR12). Demographic data, laboratory findings and serum levels of cytokines were determined.

RESULTS

Values of LS decreased from 1.86 m/s to 1.68 m/s (p = 0.01) which was most pronounced in patients who had F4 fibrosis at BL (3.27 m/s to 2.37 m/s; p <  0.001). Initially elevated values of aminotransferases, ferritin, IgG (p <  0.001 each) and international normalized ratio (p <  0.003) declined, thrombocyte count (p = 0.007) increased. Correlations of these laboratory parameters with BL levels of LS measurement (LSM) were most apparent in patients with F1-F3 fibrosis. Tumor necrosis factor (TNF)-α (p = 0.031), interleukin (IL)-10 (p = 0.005) and interferon y inducible protein (IP)-10 (p <  0.001) decreased in parallel with LSM under DAA therapy and corelated with BL values.

CONCLUSION

Decrease of systemic inflammatory parameters correlated with LSM under DAA therapy. We conclude that regression of LSM is attributable to the decline of inflammation rather than reflecting fibrosis.

Tribbles homolog 2 promotes hepatic fibrosis and hepatocarcinogenesis through phosphatase 1A-Mediated stabilization of yes-associated protein

BACKGROUND & AIMS

Hepatic stellate cells (HSCs) play critical roles in liver fibrosis and hepatocellular carcinoma (HCC). Tribbles homolog 2 (TRIB2) is an oncogene implicated in a variety of cancers, including liver cancer. However, the biological function and regulatory mechanism of TRIB2 in HSCs are poorly understood. In addition, little is known about its role in liver fibrosis progression to HCC. Here, we revealed the clinical significance of TRIB2 in liver fibrosis and HCC development.

METHODS

We investigated TRIB2 promoting liver fibrosis in vitro and in vivo. In mouse model of liver fibrosis and HCC, we measured hepatic fibrosis and HCC level through knockdown TRIB2 with shRNA. In addition, we performed western blotting, real-time quantitative PCR, immunofluorescence and co-immunoprecipitation assay to study TRIB2 function in LX-2 cells.

RESULTS

TRIB2 expression was strongly upregulated in human fibrotic liver tissues and HCC tissues. TRIB2 colocalized with α-smooth muscle actin (α-SMA) in fibrotic and HCC liver tissues. Knockdown of TRIB2 inhibited HSC activation and liver fibrosis in vitro and in vivo. TRIB2 promoted Yes-associated protein (YAP) stabilization, nuclear localization, and subsequent fibrotic gene expression independent of the MST-LATS phosphorylation cascade in HSCs. TRIB2 interacted with YAP to recruit phosphatase 1A (PP1A), promoting PP1A-mediated YAP dephosphorylation. TRIB2 knockdown potently attenuated the development of fibrosis-associated liver cancer.

CONCLUSIONS

TRIB2 is an attractive target for hepatic fibrosis and fibrosis-associated liver cancer treatment.

Upregulated microRNA-132 in T helper 17 cells activates hepatic stellate cells to promote hepatocellular carcinoma cell migration in vitro

MicroRNAs play an important role in the modulation of the immune system. T helper 17 (Th17) cells are involved in the modulation of the tumour microenvironment. However, the function of miRNA in Th17 cells in the tumour microenvironment is unclear. In this study, we analysed miR-132 expression in Th17 cells and assessed the function of miR-132 on Th17 cell differentiation. In addition, the effect of miR-132 on Th17 cells in the tumour microenvironment, especially hepatic stellate cells (HSCs), was confirmed. CD4+ IL-17 ∓ cells were isolated from hepatocellular carcinoma (HCC) tumour tissues. The expression of miR-132 was higher in CD4+ IL-17 + cells than in CD4+ IL-17- cells. Human primary CD4+ T cells were used for Th17 cell differentiation. Compared with primary CD4+ T cells, Th17 cells expressed high levels of miR-132. During Th17 cell differentiation, a miR-132 mimic and inhibition were applied. After treatment with the miR-132 mimic, the differentiation of Th17 cells accelerated, showing a a higher percentage of Th17 cells and the expression and secretion of IL-17 and IL-22. Smad nuclear interacting protein 1 (SNIP1), as one of the targets of miR-132, decreased during Th17 cell differentiation-related Th17 differentiation and IL-17 expression. The conditioned medium of miR-132-overexpressing Th17 cells could increase the activation of the HSCs, which strongly promoted HCC cell migration and epithelial-mesenchymal transition (EMT). In summary, miR-132 positively regulates Th17 cell differentiation and improves the function of Th17 on HSCs for their tumour-promoting effects.

Immunotherapy for Hepatocellular Carcinoma: Current Limits and Prospects

Although many approaches have been used to treat hepatocellular carcinoma (HCC), the clinical benefits remain limited, particularly for late stage HCC. In recent years, studies have focused on immunotherapy for HCC. Immunotherapies have shown promising clinical outcomes in several types of cancers and potential therapeutic effects for advanced HCC. In this review, we summarize the immune tolerance and immunotherapeutic strategies for HCC as well as the main challenges of current therapeutic approaches. We also present alternative strategies for overcoming these limitations.

Hepatic stellate cells promote intrahepatic cholangiocarcinoma progression via NR4A2/osteopontin/Wnt signaling axis

Intrahepatic cholangiocarcinoma (ICC) is a highly fatal malignancy characterized by a vast amount of intra-tumoral fibroblasts. These fibroblasts are potentially implicated in maintaining the high aggressiveness of ICC, whereas its pro-cancer mechanisms remain scarcely reported. Here, by establishing co-culture models of ICC cells and hepatic stellate cells (HSCs), we identified that HSCs triggered the expression of nuclear receptor family 4 subgroup A member 2 (NR4A2), a transcription factor previously reported as a molecular switch between inflammation and cancer, in ICC cells. Functionally, NR4A2 promotes tumor proliferation, metastatic potentiality and represents an independent prognostic indicator for overall survival in ICC patients. Mechanistically, NR4A2 upregulates osteopontin (OPN) expression through transcriptional activation and thereby augments the activity of Wnt/β-catenin signaling. Intriguingly, in the context of co-culture, vascular endothelial growth factor (VEGF), a previously proved NR4A2 stimulus, not only enhances NR4A2 expression, but also can be blunted by the interference of the NR4A2-OPN axis. Altogether, this study suggests the NR4A2/OPN/Wnt signaling axis to be a pivotal executor of HSC-instigated cancer-promoting roles in ICC, and the NR4A2/OPN/VEGF positive feedback loop may help to reinforce the effect.

The Epigenetic Regulation of Microenvironment in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly lethal and complex malignancy strongly influenced by the surrounding tumor microenvironment. The HCC microenvironment comprises hepatic stellate cells (HSCs), tumor-associated macrophages (TAMs), stromal and endothelial cells, and the underlying extracellular matrix (ECM). Emerging evidence demonstrates that epigenetic regulation plays a crucial role in altering numerous components of the HCC tumor microenvironment. In this review, we summarize the current understanding of the mechanisms of epigenetic regulation of the microenvironment in HCC. We review recent studies demonstrating how specific epigenetic mechanisms (DNA methylation, histone regulation, and non-coding RNAs mediated regulation) in HSCs, TAMs, and ECM, and how they contribute to HCC development, so as to gain new insights into the treatment of HCC via regulating epigenetic regulation in the tumor microenvironment.

Intracellular Toxic AGEs (TAGE) Triggers Numerous Types of Cell Damage

The habitual intake of large amounts of sugar, which has been implicated in the onset/progression of lifestyle-related diseases (LSRD), induces the excessive production of glyceraldehyde (GA), an intermediate of sugar metabolism, in neuronal cells, hepatocytes, and cardiomyocytes. Reactions between GA and intracellular proteins produce toxic advanced glycation end-products (toxic AGEs, TAGE), the accumulation of which contributes to various diseases, such as Alzheimer’s disease, non-alcoholic steatohepatitis, and cardiovascular disease. The cellular leakage of TAGE affects the surrounding cells via the receptor for AGEs (RAGE), thereby promoting the onset/progression of LSRD. We demonstrated that the intracellular accumulation of TAGE triggered numerous cellular disorders, and also that TAGE leaked into the extracellular space, thereby increasing extracellular TAGE levels in circulating fluids. Intracellular signaling and the production of reactive oxygen species are affected by extracellular TAGE and RAGE interactions, which, in turn, facilitate the intracellular generation of TAGE, all of which may contribute to the pathological changes observed in LSRD. In this review, we discuss the relationships between intracellular TAGE levels and numerous types of cell damage. The novel concept of the “TAGE theory” is expected to open new perspectives for research into LSRD.

Targeting tumor-associated macrophages to synergize tumor immunotherapy

The current treatment strategies in advanced malignancies remain limited. Notably, immunotherapies have raised hope for a successful control of these advanced diseases, but their therapeutic responses are suboptimal and vary considerably among individuals. Tumor-associated macrophages (TAMs) are a major component of the tumor microenvironment (TME) and are often correlated with poor prognosis and therapy resistance, including immunotherapies. Thus, a deeper understanding of the complex roles of TAMs in immunotherapy regulation could provide new insight into the TME. Furthermore, targeting of TAMs is an emerging field of interest due to the hope that these strategies will synergize with current immunotherapies. In this review, we summarize recent studies investigating the involvement of TAMs in immune checkpoint inhibition, tumor vaccines and adoptive cell transfer therapies, and discuss the therapeutic potential of targeting TAMs as an adjuvant therapy in tumor immunotherapies.

The History of Alcoholic Liver Disease: From an Unrecognized Disease to One of the Most Frequent Diseases in Hepatology

This review describes the history of alcoholic liver disease from the beginning of the 1950s until now. It details how the hepatotoxicity of alcohol was discovered by epidemiology and basic research primarily by using new feeding techniques in rodents and primates. The article also recognizes the pioneering work of scientists who contributed to the understanding of the pathophysiology of alcoholic liver disease. In addition, clinical aspects, such as the development of diagnostics and treatment options for alcoholic liver disease, are discussed. Up-to-date knowledge of the mechanism of the disease in 2020 is presented.

Nerve fibers in the tumor microenvironment in neurotropic cancer-pancreatic cancer and cholangiocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) and cholangiocarcinoma (CCA) are both deadly cancers and they share many biological features besides their close anatomical location. One of the main histological features is neurotropism, which results in frequent perineural invasion. The underlying mechanism of cancer cells favoring growth by and through the nerve fibers is not fully understood. In this review, we provide knowledge of these cancers with frequent perineural invasion. We discuss nerve fiber crosstalk with the main different components of the tumor microenvironment (TME), the immune cells, and the fibroblasts. Also, we discuss the crosstalk between the nerve fibers and the cancer. We highlight the shared signaling pathways of the mechanisms behind perineural invasion in PDAC and CCA. Hereby we have focussed on signaling neurotransmitters and neuropeptides which may be a target for future therapies. Furthermore, we have summarized retrospective results of the previous literature about nerve fibers in PDAC and CCA patients. We provide our point of view in the potential for nerve fibers to be used as powerful biomarker for prognosis, as a tool to stratify patients for therapy or as a target in a (combination) therapy. Taking the presence of nerves into account can potentially change the field of personalized care in these neurotropic cancers.

Overcoming Challenges for CD3-Bispecific Antibody Therapy in Solid Tumors

Immunotherapy of cancer with CD3-bispecific antibodies is an approved therapeutic option for some hematological malignancies and is under clinical investigation for solid cancers. However, the treatment of solid tumors faces more pronounced hurdles, such as increased on-target off-tumor toxicities, sparse T-cell infiltration and impaired T-cell quality due to the presence of an immunosuppressive tumor microenvironment, which affect the safety and limit efficacy of CD3-bispecific antibody therapy. In this review, we provide a brief status update of the CD3-bispecific antibody therapy field and identify intrinsic hurdles in solid cancers. Furthermore, we describe potential combinatorial approaches to overcome these challenges in order to generate selective and more effective responses.

Inhibiting IRE1α-endonuclease activity decreases tumor burden in a mouse model for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a liver tumor that usually arises in patients with cirrhosis. Hepatic stellate cells are key players in the progression of HCC, as they create a fibrotic micro-environment and produce growth factors and cytokines that enhance tumor cell proliferation and migration. We assessed the role of endoplasmic reticulum (ER) stress in the cross-talk between stellate cells and HCC cells. Mice with a fibrotic HCC were treated with the IRE1α-inhibitor 4μ8C, which reduced tumor burden and collagen deposition. By co-culturing HCC-cells with stellate cells, we found that HCC-cells activate IREα in stellate cells, thereby contributing to their activation. Inhibiting IRE1α blocked stellate cell activation, which then decreased proliferation and migration of tumor cells in different in vitro 2D and 3D co-cultures. In addition, we also observed cell-line-specific direct effects of inhibiting IRE1α in tumor cells.

Serum Mac-2-Binding Protein Glycosylation Isomer at Virological Remission Predicts Hepatocellular Carcinoma and Death in Chronic Hepatitis B-Related Cirrhosis

BACKGROUND

To investigate serum Mac-2-binding protein glycosylation isomer (M2BPGi) levels in predicting hepatocellular carcinoma (HCC) and mortality at virological remission (VR, HBV DNA <20 IU/mL) following antiviral therapy in chronic hepatitis B (CHB) patients with cirrhosis.

METHODS

This retrospective cohort study included patients with CHB-related Child-Pugh A cirrhosis undergoing long-term antiviral therapy. Serum M2BPGi levels were quantified and multivariable Cox proportional hazards regression models were used to identify risk predictors for HCC and death.

RESULTS

A total of 126 and 145 patients were included in the derivation and validation cohorts, respectively. The mean age was 56, and the mean M2BPGi level was 1.86 cut-off index (COI) in the derivation cohort. After adjustment for confounders, a higher M2BPGi level at VR significantly predicted HCC (hazard ratio [HR]: 1.58, 95% confidence interval [CI]: 1.19-2.10, P=0.002) and death (HR: 2.17, 95% CI: 1.02-4.62, P=0.044). The M2BPGi ≥3 COI significantly increased the risk of HCC and death in the derivation and validation cohorts. Serial M2BPGi levels declined significantly (P=0.0001) in non-HCC patients only, and remained significantly lower than those who developed HCC afterwards (P=0.039).

CONCLUSIONS

Serum M2BPGi levels at antiviral therapy-induced VR predict HCC development and death in patients with CHB-related Child-Pugh A cirrhosis.

TGF-β2 silencing to target biliary-derived liver diseases

OBJECTIVE

TGF-β2 (TGF-β, transforming growth factor beta), the less-investigated sibling of TGF-β1, is deregulated in rodent and human liver diseases. Former data from bile duct ligated and MDR2 knockout (KO) mouse models for human cholestatic liver disease suggested an involvement of TGF-β2 in biliary-derived liver diseases.

DESIGN

As we also found upregulated TGFB2 in liver tissue of patients with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), we now fathomed the positive prospects of targeting TGF-β2 in early stage biliary liver disease using the MDR2-KO mice. Specifically, the influence of TgfB2 silencing on the fibrotic and inflammatory niche was analysed on molecular, cellular and tissue levels.

RESULTS

TgfB2-induced expression of fibrotic genes in cholangiocytes and hepatic stellate cellswas detected. TgfB2 expression in MDR2-KO mice was blunted using TgfB2-directed antisense oligonucleotides (AON). Upon AON treatment, reduced collagen deposition, hydroxyproline content and αSMA expression as well as induced PparG expression reflected a significant reduction of fibrogenesis without adverse effects on healthy livers. Expression analyses of fibrotic and inflammatory genes revealed AON-specific regulatory effects on Ccl3, Ccl4, Ccl5, Mki67 and Notch3 expression. Further, AON treatment of MDR2-KO mice increased tissue infiltration by F4/80-positive cells including eosinophils, whereas the number of CD45-positive inflammatory cells decreased. In line, TGFB2 and CD45 expression correlated positively in PSC/PBC patients and localised in similar areas of the diseased liver tissue.

CONCLUSIONS

Taken together, our data suggest a new mechanistic explanation for amelioration of fibrogenesis by TGF-β2 silencing and provide a direct rationale for TGF-β2-directed drug development.

Extracellular vesicles-derived OncomiRs mediate communication between cancer cells and cancer-associated hepatic stellate cells in hepatocellular carcinoma microenvironment

Tumor microenvironment (TME) is a critical determinant for hepatocellular carcinoma (HCC). Hepatic stellate cells (HSCs) are main interstitial cells in TME and play a vital role in early intrahepatic invasion and metastasis of HCC. The potential mechanism on the interactions between HSCs and HCC cells remains unclear. In this study, the effects of extracellular vesicles (EVs)-derived OncomiRs that mediate communication between HCC cells and cancer-associated hepatic stellate cells (caHSCs) and remold TME were investigated. The results found that the HCC cells-released EVs contained more various OncomiRs, which could activate HSCs (LX2 cells) and transform them to caHSCs, the caHSCs in turn exerted promotion effects on HCC cells through HSCs-released EVs. To further simulate the effects of OncomiRs in EVs on construction of pro-metastatic TME, a group of OncomiRs, miR-21, miR-221 and miR-151 was transfected into HCC cells and LX2 cells. These microRNAs in the EVs from OncomiRs-enhanced cells were demonstrated to have oncogenic effects on HCC cells by upregulating the activities of protein kinase B (AKT)/extracellular signal-regulated kinase (ERK) signal pathways. Equivalent results were also found in HCC xenografted tumor models. The findings suggested that the OncomiR secretion and transference by cancer cells-released EVs can mediate the communication between HCC cells and HSCs. HCC cells and caHSCs, as well as their secreted EVs, jointly construct a pro-metastatic TME suitable for invasion and metastasis of cancer cells, all these TME components form a positive feedback loop to promote HCC progression and metastasis.

Hepatic Stellate Cells and Hepatocarcinogenesis

Hepatic stellate cells (HSCs) are a significant component of the hepatocellular carcinoma (HCC) tumor microenvironment (TME). Activated HSCs transform into myofibroblast-like cells to promote fibrosis in response to liver injury or chronic inflammation, leading to cirrhosis and HCC. The hepatic TME is comprised of cellular components, including activated HSCs, tumor-associated macrophages, endothelial cells, immune cells, and non-cellular components, such as growth factors, proteolytic enzymes and their inhibitors, and other extracellular matrix (ECM) proteins. Interactions between HCC cells and their microenvironment have become topics under active investigation. These interactions within the hepatic TME have the potential to drive carcinogenesis and create challenges in generating effective therapies. Current studies reveal potential mechanisms through which activated HSCs drive hepatocarcinogenesis utilizing matricellular proteins and paracrine crosstalk within the TME. Since activated HSCs are primary secretors of ECM proteins during liver injury and inflammation, they help promote fibrogenesis, infiltrate the HCC stroma, and contribute to HCC development. In this review, we examine several recent studies revealing the roles of HSCs and their clinical implications in the development of fibrosis and cirrhosis within the hepatic TME.

Dexmedetomidine promotes the progression of hepatocellular carcinoma through hepatic stellate cell activation

Dexmedetomidine (DEX) is an anesthetic that is widely used in the clinic, and it has been reported to exhibit paradoxical effects in the progression of multiple solid tumors. In this study, we sought to explore the mechanism by which DEX regulates hepatocellular carcinoma (HCC) progression underlying liver fibrosis. We determined the effects of DEX on tumor progression in an orthotopic HCC mouse model of fibrotic liver. A coculture system and a subcutaneous xenograft model involving coimplantation of mouse hepatoma cells (H22) and primary activated hepatic stellate cells (aHSCs) were used to study the effects of DEX on HCC progression. We found that in the preclinical mouse model of liver fibrosis, DEX treatment significantly shortened median survival time and promoted tumor growth, intrahepatic metastasis and pulmonary metastasis. The DEX receptor (ADRA2A) was mainly expressed in aHSCs but was barely detected in HCC cells. DEX dramatically reinforced HCC malignant behaviors in the presence of aHSCs in both the coculture system and the coimplantation mouse model, but DEX alone exerted no significant effects on the malignancy of HCC. Mechanistically, DEX induced IL-6 secretion from aHSCs and promoted HCC progression via STAT3 activation. Our findings provide evidence that the clinical application of DEX may cause undesirable side effects in HCC patients with liver fibrosis.

Epigallocatechin Gallate Induces Hepatic Stellate Cell Senescence and Attenuates Development of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly morbid condition with lack of effective treatment options. HCC arises from chronically inflamed and damaged liver tissue; therefore, chemoprevention may be a useful strategy to reduce HCC incidence. Several reports suggest that epigallocatechin gallate (EGCG), extracted from green tea, can suppress liver inflammation and fibrosis in animal models, but its role in HCC chemoprevention is not well established. In this study, male Wistar rats were injected with diethylnitrosamine at 50 mg/kg for 18 weeks to induce cirrhosis and HCC, and EGCG was given in drinking water at a concentration of 0.02%. Clinically achievable dosing of EGCG was well-tolerated in diethylnitrosamine-injured rats and was associated with improved serum liver markers including alanine transaminase, aspartate transaminase, and total bilirubin, and reduced HCC tumor formation. Transcriptomic analysis of diethylnitrosamine-injured hepatic tissue was notable for increased expression of genes associated with the Hoshida high risk HCC gene signature, which was prevented with EGCG treatment. EGCG treatment also inhibited fibrosis progression, which was associated with inactivation of hepatic stellate cells and induction of the senescence-associated secretory phenotype. In conclusion, EGCG administered at clinically safe doses exhibited both chemopreventive and antifibrotic effects in a rat diethylnitrosamine liver injury model.

Liver, Tumor and Viral Hepatitis: Key Players in the Complex Balance Between Tolerance and Immune Activation

Liver cancer is the third most common cause of cancer related death in the World. From an epidemiological point of view the risk factors associated to primary liver cancer are mainly viral hepatitis infection and alcohol consumption. Even though there is a clear correlation between liver inflammation, cirrhosis and cancer, other emerging liver diseases (like fatty liver) could also lead to liver cancer. Moreover, the liver is the major site of metastasis from colon, breast, ovarian and other cancers. In this review we will address the peculiar status of the liver as organ that has to balance between tolerance and immune activation. We will focus on macrophages and other key cellular components of the liver microenvironment that play a central role during tumor progression. We will also discuss how current and future therapies may affect the balance toward immune activation.

Therapeutic modulators of hepatic stellate cells for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary tumor in the liver and is a leading cause of cancer-related death worldwide. Activated hepatic stellate cells (HSCs) are key components of the HCC microenvironment and play an important role in the onset and progression of HCC through the secretion of growth factors and cytokines. Current treatment modalities that include chemotherapy, radiotherapy and ablation are able to activate HSCs and remodel the tumor microenvironment. Growing evidence has demonstrated that the complex interaction between activated HSCs and tumor cells can facilitate cancer chemoresistance and metastasis. Therefore, therapeutic targeting of activated HSCs has emerged as a promising strategy to improve treatment outcomes for HCC. This review summarizes the molecular mechanisms of HSC activation triggered by treatment modalities, the function of activated HSCs in HCC, as well as the crosstalk between tumor cells and activated HSCs. Pathways of activated HSC reduction are discussed, including inhibition, apoptosis, and reversion to the inactivated state. Finally, we outline the progress and challenges of therapeutic approaches targeting activated HSCs in the development of HCC treatment.