Liver cancer stem cell dissemination and metastasis: uncovering the role of NRCAM in hepatocellular carcinoma.

BACKGROUND: Liver cancer stem cells (LCSCs) play an important role in hepatocellular carcinoma (HCC), but the mechanisms that link LCSCs to HCC metastasis remain largely unknown. This study aims to reveal the contributions of NRCAM to LCSC function and HCC metastasis, and further explore its mechanism in detail. METHODS: 117 HCC and 29 non-HCC patients with focal liver lesions were collected and analyzed to assess the association between NRCAM and HCC metastasis. Single-cell RNA sequencing (scRNA-seq) was used to explore the biological characteristics of cells with high NRCAM expression in metastatic HCC. The role and mechanism of NRCAM in LCSC dissemination and metastasis was explored in vitro and in vivo using MYC-driven LCSC organoids from murine liver cells. RESULTS: Serum NRCAM is associated with HCC metastasis and poor prognosis. A scRNA-seq analysis identified that NRCAM was highly expressed in LCSCs with MYC activation in metastatic HCC. Moreover, NRCAM facilitated LCSC migration and invasion, which was confirmed in MYC-driven LCSC organoids. The in vivo tumor allografts demonstrated that NRCAM mediated intra-hepatic/lung HCC metastasis by enhancing the ability of LCSCs to escape from tumors into the bloodstream. Nrcam expression inhibition in LCSCs blocked HCC metastasis. Mechanistically, NRCAM activated epithelial-mesenchymal transition (EMT) and metastasis-related matrix metalloproteinases (MMPs) through the MACF1 mediated ß-catenin signaling pathway in LCSCs. CONCLUSIONS: LCSCs typified by high NRCAM expression have a strong ability to invade and migrate, which is an important factor leading to HCC metastasis.

Emerging Regulatory Mechanisms Involved in Liver Cancer Stem Cell Properties in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the predominant form of primary liver cancer and one of the leading causes of cancer-related deaths worldwide. A growing body of evidence supports the hypothesis that HCC is driven by a population of cells called liver cancer stem cells (LCSCs). LCSCs have been proposed to contribute to malignant HCC progression, including promoting tumor occurrence and growth, mediating tumor metastasis, and treatment resistance, but the regulatory mechanism of LCSCs in HCC remains unclear. Understanding the signaling pathways responsible for LCSC maintenance and survival may provide opportunities to improve patient outcomes. Here, we review the current literature about the origin of LCSCs and the niche composition, describe the current evidence of signaling pathways that mediate LCSC stemness, then highlight several mechanisms that modulate LCSC properties in HCC progression, and finally, summarize the new developments in therapeutic strategies targeting LCSCs markers and regulatory pathways.

Emerging role and therapeutic application of exosome in hepatitis virus infection and associated diseases.

Hepatitis viruses are chief pathogens of hepatitis and end-stage liver diseases. Their replication and related pathogenic process highly rely on the host micro-environment and multiple cellular elements, including exosomes. Representing with a sort of cell-derived vesicle structure, exosomes were considered to be dispensable cellular components, even wastes. Along with advancing investigation, a specific profile of exosome in driving hepatitis viruses' infection and hepatic disease progression is revealed. Exosomes greatly affect the pathogenesis of hepatitis viruses by mediating their replication and modulating the host immune responses. The characteristics of host exosomes are markedly changed after infection with hepatitis viruses. Exosomes released from hepatitis virus-infected cells can carry viral nucleic or protein components, thereby acting as an effective subterfuge for hepatitis viruses by participating in viral transportation and immune escape. On the contrary, immune cell-derived exosomes contribute toward the innate antiviral immune defense and virus eradication. There is growing evidence supporting the application of exosomal biomarkers for predicting disease progress or therapeutic outcome, while exosomal nanoshuttles are regarded as promising therapeutic options based on their delivery properties and immune compatibility. In this review, we summarize the biogenesis and secretion mechanism of exosomes, review the recent findings pertaining to the role of exosomes in the interplay between hepatitis viruses and innate immune responses, and conclude their potential in further therapeutic application.

Severe acute respiratory syndrome coronavirus 2 for physicians: Molecular characteristics and host immunity (Review).

Recently, severe acute respiratory syndrome (SARS) coronavirus (CoV) 2 (SARS­CoV­2)­causing CoV disease 2019 (COVID­19) emerged in China and has become a global pandemic. SARS­CoV­2 is a novel CoV originating from ß­CoVs. Major distinctions in the gene sequences between SARS­CoV and SARS­CoV­2 include the spike gene, open reading frame (ORF) 3b and ORF 8. SARS­CoV­2 infection is initiated when the virus interacts with angiotensin­converting enzyme 2 (ACE2) receptors on host cells. Through this mechanism, the virus infects the alveolar, esophageal epithelial, ileum, colon and other cells on which ACE2 is highly expressed, causing damage to target organs. To date, host innate immunity may be the only identified direct factor associated with viral replication. However, increased ACE2 expression may upregulate the viral load indirectly by increasing the baseline level of infectious virus particles. The peak viral load of SARS­CoV­2 is estimated to occur ~10 days following fever onset, causing patients in the acute stage to be the primary infection source. However, patients in the recovery stage or with occult infections can also be contagious. The host immune response in patients with COVID­19 remains to be elucidated. By studying other SARS and Middle East respiratory syndrome coronaviruses, it is hypothesized that patients with COVID­19 may lack sufficient antiviral T­cell responses, which consequently present with innate immune response disorders. This may to a certain degree explain why this type of CoV triggers severe inflammatory responses and immune damage and its associated complications.

Effect of silibinin capsules combined with lifestyle modification on hepatic steatosis in patients with chronic hepatitis B.

The coexistence of HBV infection and hepatic steatosis is a novel characteristic of liver disease. Silibinin capsules (SC) is a silybin-phospholipid complex containing silybin as the bioactive component, which exerts a remarkable biological effect on various liver diseases, including nonalcoholic fatty liver disease (NAFLD). The purpose of this study was to investigate (1) the prevalence of hepatic steatosis in the general population and patients with chronic hepatitis B (CHB) and (2) to evaluate the effect of SC combined with therapeutic lifestyle changes (TLC) compared with TLC alone on hepatic steatosis in patients with CHB. A total of 16,451 individuals underwent transient elastography (TE) with the control attenuation parameter (CAP) measurement, among which the prevalence of hepatic steatosis was 31.1% in patients with CHB and 42.2% in the general population. The prevalence of hepatic steatosis differed between patients with CHB and the general population at an age of 40 years or older but was similar in individuals aged 39 years or younger (p < 0.05). Furthermore, in patients with CHB presenting hepatic steatosis, the post-6-month relative reduction in CAP in the SC combined with TLC group (p = 0.001) was significantly greater than in the TLC alone group (p = 0.183). The CAP distribution of different steatosis grades (S1, S2, and S3) in the SC combined with TLC group was decreased and S0 (CAP < 248 dB/m) increased significantly, but not significant in the TLC group. Thus, SC combined with TLC may effectively improve hepatic steatosis in patients with CHB.

Hepatocyte nuclear factor 4α and cancer-related cell signaling pathways: a promising insight into cancer treatment.

Hepatocyte nuclear factor 4α (HNF4α), a member of the nuclear receptor superfamily, is described as a protein that binds to the promoters of specific genes. It controls the expression of functional genes and is also involved in the regulation of numerous cellular processes. A large number of studies have demonstrated that HNF4α is involved in many human malignancies. Abnormal expression of HNF4α is emerging as a critical factor in cancer cell proliferation, apoptosis, invasion, dedifferentiation, and metastasis. In this review, we present emerging insights into the roles of HNF4α in the occurrence, progression, and treatment of cancer; reveal various mechanisms of HNF4α in cancer (e.g., the Wnt/ß-catenin, nuclear factor-κB, signal transducer and activator of transcription 3, and transforming growth factor ß signaling pathways); and highlight potential clinical uses of HNF4α as a biomarker and therapeutic target for cancer.

Hepatitis B Virus Infection: Overview.

Hepatitis B virus (HBV) is a DNA virus, belonging to the Hepadnaviridae family. It is a partially double-stranded DNA virus with a small viral genome (3.2 kb). Chronic HBV infection remains a global public health problem. If left untreated, chronic HBV infection can progress to end-stage liver disease, such as liver cirrhosis and hepatocellular carcinoma (HCC). In recent years, tremendous advances in the field of HBV basic and clinical research have been achieved, ranging from the HBV biological characteristics, immunopathogenesis, and animal models to the development of new therapeutic strategies and new drugs against HBV. In this overview, we begin with a brief history of HBV discovery and treatment milestones. We then briefly summarize the HBV research advances, which will be detailed in the following chapters.

Exosome-mediated communication in the tumor microenvironment contributes to hepatocellular carcinoma development and progression.

The tumor microenvironment (TME) is an essential intrinsic portion of hepatocellular carcinoma (HCC) for the regulation of its origination, development, invasion, and metastasis. As emerging components of the tumor-host interaction, exosomes are increasingly recognized as professional carriers of information in TME and as pivotal molecular entities involved in tumorigenic microenvironment setup. However, much remains unknown about the role of the exosome communication system within TME in the development and progression of HCC. In this review, we focus on the roles and probable mechanisms of TME in HCC and show the exosome-based immune regulation in TME to promote HCC. Multiple processes are involved in HCC, including tumor survival, growth, angiogenesis, invasion, and metastasis. We also discuss the specific roles of exosomes in HCC processes by molding hospitable TME for HCC, such as providing energy, transmitting protumor signals, and evading inhibitory signals. In addition, exosomes induce angiogenesis by changing the biological characteristics of endothelial cells and directly regulating proangiogenic and propermeability factors. Furthermore, exosomes may lead to HCC metastatic invasion by epithelial-mesenchymal transformation, extracellular matrix degradation, and vascular leakage. Finally, we summarize the therapeutic usage of exosomes in the HCC microenvironment and attempt to provide a theoretical reference for modern antitumor agents designed to target these mechanisms.

Exosomal Interferon-Induced Transmembrane Protein 2 Transmitted to Dendritic Cells Inhibits Interferon Alpha Pathway Activation and Blocks Anti-Hepatitis B Virus Efficacy of Exogenous Interferon Alpha.

The negative regulators in the interferon (IFN) signaling pathway inhibit intrahepatic immune response, resulting in suboptimal therapeutic response to IFNα treatment in chronic hepatitis B (CHB) patients. Identifying the key negative factors and elucidating the regulating mechanism are essential for improving anti-HBV (hepatitis B virus) efficacy of IFNα. From the Gene Expression Omnibus (GEO) database, we downloaded and analyzed gene expression profiles of CHB patients with different responses to IFNα (GSE54747), and found that innate immune status was associated with the IFNα-based therapeutic response in CHB patients. Through PCR array, we found higher baseline level of IFN-induced transmembrane protein 2 (IFITM2) mRNA and lower baseline level of IFNα mRNA in peripheral blood mononuclear cells (PBMCs) of CHB patients with suboptimal response to IFNα treatment. Increased IFITM2 protein was also found in the serum of IFNα nonresponsive patients. With further experiments, we found that overexpressing IFITM2 in Huh7 cells suppressed endogenous IFNα synthesis by inhibiting phosphorylation of extracellular signal-regulated kinase (ERK), TANK-binding kinase 1 (TBK1), and interferon regulatory factor 3 (IRF3); knocking out IFITM2 enhanced activation of the endogenous IFNα synthesis pathway, exhibiting better inhibition on HBV replication. We also found that IFITM2 protein was shuttled by exosomes to dendritic cells (DCs), the main source of endogenous IFNα. Exosome-mediated transport of IFITM2 inhibited synthesis of endogenous IFNα in DCs whereas the inhibitory effect was abolished when IFITM2 was knocked out. Furthermore, we demonstrated that both palmitoylation inhibitor and mutation on 70/71 sites of IFITM2 protein influenced its incorporation into exosomes. Mutated IFITM2 protein increased the effect of IFNα against HBV. Conclusion: Exosome-mediated transport of IFITM2 to DCs inhibits IFNα pathway activation and blocks anti-HBV efficacy of exogenous IFNα. The findings provide an explanation to the suboptimal response of CHB patients to IFNα treatment.

A retrospective study of the efficacy of sofosbuvir plus NS5A inhibitors for patients with hepatitis C virus genotype-2 chronic infection.

BACKGROUND: A combination of sofosbuvir (SOF)+NS5A inhibitor therapies is the main treatment for patients with hepatitis C virus (HCV) genotype-2 (GT-2) chronic infection, but the data are rarely reported in China. This study aimed to investigate the virological response and liver fibrosis improvement among GT-2 patients receiving SOF+NS5A inhibitors. PATIENTS AND METHODS: In this retrospective study, patients who received SOF+NS5A inhibitors between March 2016 and July 2017 were recruited. The treatment duration was 12 weeks and the treatment strategies included SOF+daclatasvir, SOF/ledipasvir, and SOF/velpatasvir. The primary endpoint was a sustained virologic response (serum HCV RNA undetectable) at week 12 after the end of therapy and the secondary endpoint was the improvement in liver stiffness and scores of apartate aminotransferase to platelet ratio index and fibrosis-4. RESULTS: A total of 30 GT-2 patients were enrolled, with 13 (43.3%) patients in SOF+daclatasvir, 13 (43.3%) patients in SOF/ledipasvir, and four (13.3%) patients in SOF/velpatasvir. All patients [30/30 (100%)] achieved SVR, irrespective of treatment regimens and degree of liver fibrosis. After the treatment, liver fibrosis scores of apartate aminotransferase to platelet ratio index (2.27±2.14 vs. 0.89±0.77, P=0.003) and fibrosis-4 (1.17±1.22 vs. 0.42±0.25, P=0.013) were both significantly lower than those before treatment. CONCLUSION: SOF+NS5A inhibitor therapies may induce an excellent virological response and fibrosis improvement in HCV GT-2-infected patients.

Satisfactory virological response and fibrosis improvement of sofosbuvir-based regimens for Chinese patients with hepatitis C virus genotype 3 infection: results of a real-world cohort study.

BACKGROUND: Chronic hepatitis C virus (HCV) genotype (GT) 3 infection with advanced liver disease has emerged as a challenging to treat by direct-acting antivirals (DAAs), but the efficacy of DAAs in Chinese HCV-GT3 patients is rarely reported. This study aimed to analyze the efficacy of sofosbuvir (SOF)-based regimens in Chinese patients with HCV-GT3 and compensated liver disease. METHODS: This was a registered retrospective study. All patients had completed at least 12 weeks SOF-based regimens therapy (with or without RBV), and were followed up for at least 24 weeks after therapy discontinuation. The primary endpoint was sustained virological response 24 weeks after end of therapy (SVR24). RESULTS: A total of 102 patients who completed at least 12 weeks therapy were finally included, with 57 in SOF + Daclatasvir (SOF + DCV), 24 in SOF + DCV + ribavirin (RBV) and 21 in SOF/Velpatasvir (SOF/VEL). The total SVR24 rate was achieved in 90.20% (92/102), with 85.96% (49/57) in SOF + DCV, 91.67% (22/24) in SOF + DCV + RBV and 100.00% (21/21) in SOF/VEL. Among 10 relapsed patients (8 in SOF + DCV and 2 in SOF + DCV + RBV), the short course (12 weeks) of therapy and no RBV addition may be the leading cause. In this cohort, the SVR24 rate was not statistically different between patients with and without cirrhosis (81.82% [27/33] vs. 94.20% [65/69], P = 0.073). Additionally, both FIB-4 (4.03 vs. 2.08, P < 0.001) and APRI (2.15 vs. 0.68, P < 0.001) scores were significant improved from baseline to week 24 after completion of therapy, regardless of the presence of cirrhosis. CONCLUSION: SOF-based regimens are highly effective in viral clearance and fibrosis remission for Chinese patients with HCV-GT3 infection. If available, SOF/VEL should be first considered.