The role of signaling pathways in the development and treatment of hepatocellular carcinoma

Low Birth Weight Intensifies Changes in Markers of Hepatocarcinogenesis Induced by Fructose Consumption in Rats

Intrauterine growth restriction (IUGR) due to fetal exposure to glucocorticoid excess results in metabolic inflexibility and hepatic steatosis upon nutritional stress during adulthood. We previously demonstrated that rats born to dexamethasone (DEX)-treated mothers developed hepatic steatosis when exposed to 10% fructose solution during adult life. Persistent triacylglyceride (TAG) accumulation in the liver, in turn, is a feature of non-alcoholic fatty liver disease (NAFLD), which serves as a risk factor for non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC). In the present study, we demonstrate that the combination of IUGR and fructose treatment during adulthood also results in increased hepatic myeloperoxidase (MPO) activity, AKT phosphorylation and serum aspartate transaminase. Growth-restricted rats also presented reduced hepatic TRIB3 and GADD45a after fructose treatment. Other markers of cell proliferation, such as Cyclin D, PCNA, Hgf and Hspa4/Hsp70 expression and the number of Ki-67 positive cells, were all increased in the liver of growth- restricted rats treated with fructose. On the other hand, the combination of IUGR and fructose treatment during adult life reduced the levels of IGF-1. In conclusion, our data indicate that after exposure to fructose, adult rats subjected to dexamethasone-induced IUGR display exacerbated molecular changes in markers of NASH and HCC.

Epidermal Growth Factor Receptor immunohistochemical expression in hepatocellular carcinoma without Epidermal Growth Factor Receptor exons 18–21 mutations

Introduction: EGFR targeted therapies, have been proved beneficial for patients with HCC, nevertheless additional research on EGFR immunoexpresion and EGFR mutations is still needed, especially in population in which it has not been done yet. The aim of this study is to evaluate EGFR immunoexpression in HCC without EGFR exons 18–21 mutations and to evaluate its influence on survival in HCC patients in North Macedonia.

Methods: We studied 31 cases of HCC for EGFR immunohistochemical expression and EGFR exons 18–21 mutations. The following clinical parameters were analyzed: Hepatitis B and C virus infection, presence of cirrhosis, tumor size, enlarged lymph nodes, metastases, alpha fetoprotein level and overall survival. Presence of the EGFR immunosignal (membranous and cytoplasmic) and the percentage of positive tumor cells in the entire tumor tissue specimen were semi-quantitatively determined.

Results: Hepatitis B and C virus infection, tumor size, metastatic disease and EGFR immunoexpression have influence on patient’s survival. No EGFR exons 18–21 mutations were detected in this group of HCCs. EGFR expression of 61%–80% in tumor tissue significantly influenced survival of the patients (p < 0.01). Multiple Cox regression confirmed tumor size of 5–10 cm (p < 0.05), tumor size > 10 cm (p < 0.01) and EGFR expression in range of 61% to 80% (p < 0.05) as independent survival predictors in patients with HCC.

Conclusion: EGFR overexpression in range of 61% to 80% was an independent survival predictor in patients with HCC, implying that these patients could benefit from EGFR inhibition. However, the absence of EGFR mutations in exons 18–21 in any of the cases of this study suggest that single drug EGFR targeted therapy in patients with HCC may be insufficient.

Z-Guggulsterone Is a Potential Lead Molecule of Dawa-ul-Kurkum against Hepatocellular Carcinoma

An ancient saffron-based polyherbal formulation, Dawa-ul-Kurkum (DuK), has been used to treat liver ailments and other diseases and was recently evaluated for its anticancer potential against hepatocellular carcinoma (HCC) by our research team. To gain further insight into the lead molecule of DuK, we selected ten active constituents belonging to its seven herbal constituents (crocin, crocetin, safranal, jatamansone, isovaleric acid, cinnamaldehyde, coumaric acid, citral, guggulsterone and dehydrocostus lactone). We docked them with 32 prominent proteins that play important roles in the development, progression and suppression of HCC and those involved in endoplasmic reticulum (ER) stress to identify the binding interactions between them. Three reference drugs for HCC (sorafenib, regorafenib, and nivolumab) were also examined for comparison. The in silico studies revealed that, out of the ten compounds, three of them—viz., Z-guggulsterone, dehydrocostus lactone and crocin—showed good binding efficiency with the HCC and ER stress proteins. Comparison of binding affinity with standard drugs was followed by preliminary in vitro screening of these selected compounds in human liver cancer cell lines. The results provided the basis for selecting Z-guggulsterone as the best-acting phytoconstituent amongst the 10 studied. Further validation of the binding efficiency of Z-guggulsterone was undertaking using molecular dynamics (MD) simulation studies. The effects of Z-guggulsterone on clone formation and cell cycle progression were also assessed. The anti-oxidant potential of Z-guggulsterone was analyzed through DPPH and FRAP assays. qRTPCR was utilized to check the results at the in vitro level. These results indicate that Z-guggulsterone should be considered as the main constituent of DuK instead of the crocin in saffron, as previously hypothesized.

Up-Regulation of RACGAP1 Promotes Progressions of Hepatocellular Carcinoma Regulated by GABPA via PI3K/AKT Pathway

Hepatocellular carcinoma (HCC) is one of the dominating tumors causing death due to lack of timely discovery and valid treatment. Abnormal increase of Rac GTPase activating protein 1 (RACGAP1) has been verified to be an oncogene in plenty tumors. The profound mechanism of RACGAP1 was rarely reported in HCC. In this study, we explored the function and mechanism of RACGAP1 in HCC through multiple analysis and experiments. RACGAP1 expression was up-regulated in HCC samples and the high expression of RACGAP1 was an independent prognostic risk factor for HCC patients. Meanwhile, RACGAP1 promoted developments of HCC both in vitro and in vivo. We verified that RACGAP1 promoted proliferation of HCC via PI3K/AKT/CDK2 and PI3K/AKT/GSK3β/Cyclin D1 signaling pathway. RACGAP1 accelerated the invasion and metastasis of HCC via phosphorylation of GSK3β and nuclear translocation of β-catenin. Furthermore, by luciferase reporter assay and Chromatin immunoprecipitation (ChIP) assay, we confirmed Recombinant GA Binding Protein Transcription Factor Alpha (GABPA) regulated the transcription of RACGAP1. All these findings revealed that RACGAP1 promotes the progression of HCC through a novel mechanism, which might be a new therapeutic target for HCC patients.

Cucurbitacin I exhibits anticancer efficacy through induction of apoptosis and modulation of JAK/STAT3, MAPK/ERK, and AKT/mTOR signaling pathways in HepG2 cell line

Hepatocellular carcinoma is a common cancer type, especially among men. Although cucurbitacin I (CuI), widely found in plants belonging to the Ecballium elaterium (E. L) plant family, has been shown to have antitumorigenic properties in many cancer types, its anticancer effect, molecular mechanism, and apoptotic effect mediated by signal pathways on hepatocellular carcinoma have not been fully clarified. In the present study, we investigated the anticancer effect of CuI treated at different doses on the HepG2 cell line and the underlying mechanism in vitro. High-purity CuI was obtained from the E. elaterium plant with the aid of HPLC. The effects of this substance on the viability of cells were studied by the MTT assay. The effects of CuI on cell cycle progression and apoptosis were studied with flow cytometry. DNA breaks were analyzed by the Comet assay method. The proteins and genes involved in the JAK/STAT3, MAPK/ERK, and AKT/mTOR signaling pathways were investigated using Western blot and qRT-PCR, respectively. The results of this study demonstrated that CuI significantly reduced HepG2 cell growth in vitro, induced antiproliferation, and G2/M phase of the cell cycle was interrupted. PRACTICAL APPLICATIONS: CuI administration was shown to downregulate the levels of proteins in the PI3K/AKT/mTOR, MAPK, and JAK2/STAT3 cascades in HepG2 cells. CuI also reduced the expression of MAPK, STAT3, mTOR, JAK2, and Akt genes in different concentrations. DNA breaks are formed as a result of this effect. CuI, by reducing cell proliferation and promoting apoptosis, was found to have potential as a chemotherapeutic agent of hepatocellular carcinoma.

Novel artemisinin derivative FO8643 with anti-angiogenic activity inhibits growth and migration of cancer cells via VEGFR2 signaling

The vascular endothelial growth factor receptor 2 (VEGFR2) is widely recognized as a key effector in angiogenesis and cancer progression and has been considered a critical target for the development of anti-cancer drugs. Artemisinin (ARS) and its derivatives exert profound efficacy in treating not only malaria but also cancer. As a novel ARS-type compound, FO8643 caused significant suppression of the growth of a panel of cancer cells, including both solid and hematologic malignancies. In CCRF-CEM leukemia cells, FO8643 dramatically inhibited cell proliferation coupled with increased apoptosis and cell cycle arrest. Additionally, FO8643 restrained cell migration in the 2D wound healing assay as well as in a 3D spheroid model of human hepatocellular carcinoma HUH-7 cells. Importantly, SwissTargetPrediction predicted VEGFR2 as an underlying target for FO8643. Molecular docking simulation further indicated that FO8643 forms hydrogen bonds and hydrophobic interactions within the VEGFR2 kinase domain. Moreover, FO8643 directly inhibited VEGFR2 kinase activity and its downstream action including MAPK and PI3K/Akt signaling pathways in HUH-7 cells. Encouragingly, FO8643 decreased angiogenesis in the chorioallantoic membrane assay in vivo. Collectively, FO8643 is a novel ARS-type compound exerting potential VEGFR2 inhibition. FO8643 may be a viable drug candidate in cancer therapy.

JIB-04, a Pan-Inhibitor of Histone Demethylases, Targets Histone-Lysine-Demethylase-Dependent AKT Pathway, Leading to Cell Cycle Arrest and Inhibition of Cancer Stem-Like Cell Properties in Hepatocellular Carcinoma Cells

JIB-04, a pan-histone lysine demethylase (KDM) inhibitor, targets drug-resistant cells, along with colorectal cancer stem cells (CSCs), which are crucial for cancer recurrence and metastasis. Despite the advances in CSC biology, the effect of JIB-04 on liver CSCs (LCSCs) and the malignancy of hepatocellular carcinoma (HCC) has not been elucidated yet. Here, we showed that JIB-04 targeted KDMs, leading to the growth inhibition and cell cycle arrest of HCC, and abolished the viability of LCSCs. JIB-04 significantly attenuated CSC tumorsphere formation, growth, relapse, migration, and invasion in vitro. Among KDMs, the deficiency of KDM4B, KDM4D, and KDM6B reduced the viability of the tumorspheres, suggesting their roles in the function of LCSCs. RNA sequencing revealed that JIB-04 affected various cancer-related pathways, especially the PI3K/AKT pathway, which is crucial for HCC malignancy and the maintenance of LCSCs. Our results revealed KDM6B-dependent AKT2 expression and the downregulation of E2F-regulated genes via JIB-04-induced inhibition of the AKT2/FOXO3a/p21/RB axis. A ChIP assay demonstrated JIB-04-induced reduction in H3K27me3 at the AKT2 promoter and the enrichment of KDM6B within this promoter. Overall, our results strongly suggest that the inhibitory effect of JIB-04 on HCC malignancy and the maintenance of LCSCs is mediated via targeting the KDM6B-AKT2 pathway, indicating the therapeutic potential of JIB-04.

Distinct Gene Expression Profiles in Viable Hepatocellular Carcinoma Treated With Liver-Directed Therapy

Background

Hepatocellular carcinoma is a heterogeneous tumor that accumulates a mutational burden and dysregulated signaling pathways that differ from early to advanced stages. Liver transplant candidates with early-stage hepatocellular carcinoma (HCC) undergo liver-directed therapy (LDT) to delay disease progression and serve as a bridge to liver transplantation (LT). Unfortunately, &gt;80% of LDT-treated patients have viable HCC in the explant liver, dramatically increasing recurrence risk. Understanding the effect of LDT on early-stage HCC could help identify therapeutic targets to promote complete pathologic necrosis and improve recurrence-free survival. In this study, transcriptomic data from viable HCC in LDT-treated bridged to transplant patients were investigated to understand how treatment may affect tumor signaling pathways.

Methods

Multiplex transcriptomic gene analysis was performed with mRNA extracted from viable tumors of HCC patients bridged to transplant using LDT. The NanoString nCounter® Tumor Signaling 360 panel was used that contained 780 genes from 48 pathways involved in tumor biology within the microenvironment as well as antitumoral immune responses.

Results

Hierarchical clustering separated tumors into three subtypes (HCC-1, HCC-2, and HCC-3) each with distinct differences in anti-tumoral signaling and immune infiltration within the tumor microenvironment. Immune infiltration (neutrophils, T cells, and macrophages) were all lowest in subtype HCC-3. The tumor inflammatory signature consisting of 18 genes associated with PD-1/PD-L1 inhibition, antigen presentation, chemokine secretion, and adaptive immune responses was highest in subtype HCC-1 and lowest in HCC-3. History of decompensation and etiology were associated with HCC subtype favoring downregulations in inflammation and immune infiltration with upregulation of lipid metabolism. Gene expression among intrahepatic lesions was remarkably similar with &gt;85% of genes expressed in both lesions. Genes differentially expressed (&lt;8 genes per patient) in multifocal disease were all upregulated in LDT-treated tumors from pathways involving epithelial mesenchymal transition, extracellular matrix remodeling, and/or inflammation potentially implicating intrahepatic metastases.

Conclusion

Incomplete response to LDT may drive expression patterns that inhibit an effective anti-tumoral response through immune exclusion and induce intrahepatic spread.

Human amniotic mesenchymal stem cells-derived IGFBP-3, DKK-3, and DKK-1 attenuate liver fibrosis through inhibiting hepatic stellate cell activation by blocking Wnt/β-catenin signaling pathway in mice

Background

Liver fibrosis is an outcome of restoring process in chronic liver injury. Human amniotic mesenchymal stem cells (hAMSCs) derived from amniotic membrane have multilineage differentiation, immunosuppressive, and anti-inflammatory potential which makes them suitable for treating liver fibrosis. This study aimed to explore the effect and mechanism of hAMSCs on liver fibrosis.

Methods

hAMSCs were transplanted into carbon tetrachloride (CCl₄)-induced liver fibrosis mice via tail vein, and the effects of hAMSCs on hepatic fibrosis were assessed. The effects of hAMSCs and hAMSCs conditional medium (CM) on the activation of hepatic stellate cells (HSCs) were investigated in vivo and in vitro. Antibody array assay was used to identify the cytokines secreted by hAMSCs that may inhibit the activation of HSCs. Finally, the underlying mechanisms were explored by assessing IGF-1R/PI3K/AKT and GSK3β/β-catenin signaling pathways in the activated HSCs (LX-2) with hAMSCs and hAMSCs transfected with corresponding siRNAs.

Results

Our results showed that hAMSCs possessed the characterizations of mesenchymal stem cells. hAMSCs significantly reduced liver fibrosis and improved liver function in mice by inhibiting HSCs activation in vivo. Both hAMSCs and hAMSC-CM remarkably inhibited the collagen deposition and activation of LX-2 cells in vitro. Antibody array assay showed that insulin-like growth factor binding protein-3 (IGFBP-3), Dickkopf-3 (DKK-3), and Dickkopf-1 (DKK-1) were highly expressed in the co-culture group and hAMSC-CM group compared with LX-2 group. Western blot assay demonstrated that IGFBP-3, DKK-3, and DKK-1 derived from hAMSCs inhibit LX-2 cell activation through blocking canonical Wnt signaling pathway.

Conclusions

Our results demonstrated that IGFBP-3, Dkk3, and DKK-1 secreted by hAMSCs attenuated liver fibrosis in mice through inhibiting HSCs activation via depression of Wnt/β-catenin signaling pathway, suggesting that hAMSCs or hAMSC-CM provides an alternative therapeutic approach for the treatment of liver fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02906-z.

IFN-γ affects pancreatic cancer properties by MACC1-AS1/MACC1 axis via AKT/mTOR signaling pathway

BACKGROUND

Metastasis-related in colon cancer 1 (MACC1) is highly expressed in a variety of solid tumours, but its role in pancreatic cancer (PC) remains unknown. Interferon gamma (IFN-γ) affecting MACC1 expression was explored as the potential mechanism following its intervention.

METHODS

Expressions of MACC1 treated with IFN-γ gradient were confirmed by quantitative real-time PCR (qRT-PCR) and western blot (WB). Proliferation, migration, and invasion abilities of PC cells treated with IFN-γ were analysed by CCK8, EDU, colony formation, Transwell (with or without matrix gel) and wound-healing assays. Expression of antisense long non-coding RNA of MACC1, MACC1-AS1, and proteins of AKT/mTOR pathway, (pho-)AKT, and (pho-)mTOR was also assessed by qRT-PCR and WB. SiRNA kit and lentiviral fluid were conducted for transient expression of MACC1 and stable expression of MACC1-AS1, respectively. Rescue assays of cells overexpressing MACC1-AS1 and of cells silencing MACC1 were performed and cellular properties and proteins were assessed by the above-mentioned assays as well.

RESULTS

IFN-γ inhibited MACC1 expression in a time- and dose-dependent manner; 100 ng/mL IFN-γ generally caused downregulation of most significant (p ≤ 0.05). In vitro experiments revealed that IFN-γ decreased cellular proliferation, migration, and invasion abilities and downregulated the expression of pho-AKT and pho-mTOR (p ≤ 0.05). Conversely, overexpression of MACC1-AS1 upregulated pho-AKT and pho-mTOR proteins, and reversed cellular properties (p ≤ 0.05). Rescue assays alleviated the above changes of pho-AKT/ mTOR and cellular properties.

CONCLUSION

IFN-γ affected PC properties by MACC1-AS1/MACC1 axis via AKT/mTOR signaling pathway, which provides novel insight for candidate targets for treating PC.

Suppressors of Cytokine Signaling and Hepatocellular Carcinoma

Simple Summary

Hepatocellular carcinoma (HCC) is a common malignancy worldwide. The HCC generally develops in the liver of patients already suffering from chronic liver disease. There have been significant advances in both the curative and palliative treatment of HCC. Although liver resection is a curative treatment for HCC, its indication is often limited due to an impaired liver function reservoir. There is still a need to understand how to control liver regeneration after resection and find better cancer immunotherapy and anticancer drugs for advanced HCC. Suppressors of cytokine signaling (SOCS) negatively regulate cytokine signaling related to cell proliferation, differentiation, and immune response; therefore, SOCS are thought to play an important role in HCC development and liver regeneration.

Abstract

Cytokines are secreted soluble glycoproteins that regulate cellular growth, proliferation, and differentiation. Suppressors of cytokine signaling (SOCS) proteins negatively regulate cytokine signaling and form a classical negative feedback loop in the signaling pathways. There are eight members of the SOCS family. The SOCS proteins are all comprised of a loosely conserved N-terminal domain, a central Src homology 2 (SH2) domain, and a highly conserved SOCS box at the C-terminus. The role of SOCS proteins has been implicated in the regulation of cytokines and growth factors in liver diseases. The SOCS1 and SOCS3 proteins are involved in immune response and inhibit protective interferon signaling in viral hepatitis. A decreased expression of SOCS3 is associated with advanced stage and poor prognosis of patients with hepatocellular carcinoma (HCC). DNA methylations of SOCS1 and SOCS3 are found in HCC. Precise regulation of liver regeneration is influenced by stimulatory and inhibitory factors after partial hepatectomy (PH), in particular, SOCS2 and SOCS3 are induced at an early time point after PH. Evidence supporting the important role of SOCS signaling during liver regeneration also supports a role of SOCS signaling in HCC. Immuno-oncology drugs are now the first-line therapy for advanced HCC. The SOCS can be potential targets for HCC in terms of cell proliferation, cell differentiation, and immune response. In this literature review, we summarize recent findings of the SOCS family proteins related to HCC and liver diseases.

PI3K/AKT/mTOR Pathway-Associated Genes Reveal a Putative Prognostic Signature Correlated with Immune Infiltration in Hepatocellular Carcinoma

Background

The dysregulated PI3K/AKT/mTOR pathway acts as the main regulator of tumorigenesis in hepatocellular carcinoma (HCC).

Aim

Here, we identify the prognostic significance of PI3K/AKT/mTOR pathway-associated genes (PAGs) as well as their putative signature based on PAGs in an HCC patient's cohort.

Methods

The transcriptomic data and clinical feature sets were queried to extract the putative prognostic signature.

Results

We identified nine PAGs with different expressions. GO and KEGG indicated that these differentially expressed genes were associated with various carcinogenic pathways. Based on the signature-computed median risk score, we categorized the patients into groups of low risk and high risk. The survival time for the low-risk group is longer than that of the high-risk group in Kaplan-Meier (KM) curves. The prognostic value of risk score (ROC = 0.736) of receiver operating characteristic (ROC) curves performed better in comparison to that of other clinicopathological features. In both the GEO database and ICGC database, these outcomes were verified. The predictions of the overall survival rates in HCC patients of 1 year, 3 years, and 5 years can be obtained separately from the nomogram. The risk score was associated with the immune infiltrations of CD8 T cells, activated CD4 memory T cells, and follicular helper T cells, and the expression of immune checkpoints (PD-1, TIGIT, TIM-3, BTLA, LAG-3, and CTLA4) was positively relevant to the risk score. The sensitivity to several chemotherapeutic drugs can also be revealed by the signature. CDK1, PITX2, PRKAA2, and SFN were all upregulated in the tumor tissue of clinical samples.

Conclusion

A putative and differential dataset-validated prognostic signature on the basis of integrated bioinformatic analysis was established in our study, providing the immunotherapeutic targets as well as the personalized treatment in HCC with neoteric insight.

Integrated Analysis of the Altered lncRNA, microRNA, and mRNA Expression in HBV-Positive Hepatocellular Carcinoma

Hepatitis B virus (HBV) infection is the most prominent risk factor for developing hepatocellular carcinoma (HCC), which can increase the incidence of HCC by more than 100 times. Accumulated evidence has revealed that non-coding RNAs (ncRNAs) play a regulatory role in various tumors through the long non-coding RNA (lncRNA)–microRNA (miRNA)–mRNA regulation axis. However, the involvement of the ncRNA regulatory network in the progression of HBV infection-induced HCC remains elusive. In the current work, five tumor samples from patients with hepatitis B surface antigen (HBsAg)-positive HCC and three tumor samples from patients with HBsAg-negative HCC were collected for whole-transcriptome sequencing. Between the two groups, 841 lncRNAs, 54 miRNAs, and 1118 mRNAs were identified to be differentially expressed (DE). The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that DE genes were mainly involved in cancer-related pathways, including Wnt and MAPK signaling pathways. The Gene Expression Omnibus (GEO) analysis further validated the selected DE mRNAs. The DE lncRNA–miRNA–mRNA network was built to explore the effect of HBV infection on the regulation of ncRNAs in HCC. These findings provide novel insights into the role of HBV infection in the progression of HCC.

Clusterin and Related Scoring Index as Potential Early Predictors of Response to Sorafenib in Hepatocellular Carcinoma

Advanced hepatocellular carcinoma (HCC) remains a highly lethal malignancy, although several systemic therapeutic options are available, including sorafenib (SFN), which has been one of the standard treatment agents for almost a decade. As early prediction of response to SFN remains challenging, biomarkers that enable early prediction using a clinically feasible method are needed. Here, we report that the serum secretory form of clusterin (sCLU) protein and its related predictive index are potential beneficial biomarkers for early prediction of SFN response. Using high-throughput screening and subsequent multivariate analysis in the derivation cohort, we found that changes in the concentrations of CLU, vascular cell adhesion molecule-1 (VCAM1), and α-fetoprotein were significantly associated with response to SFN. Furthermore, we confirmed that an increase in CLU serum level 1 month after treatment initiation was significantly associated with shorter progression-free survival. In addition, "NR-index," which comprises these proteins, was evaluated as a tool for accurately predicting the efficacy of SFN and confirmed in the validation cohort. We also established SFN-resistant HepG2 cells (HepG2-SR) and found that sCLU significantly increased in HepG2-SR cells compared with normal HepG2 cells, and confirmed that HepG2-SR cells treated with SFN were resistant to apoptosis. The mechanism underlying activation of sCLU expression in acquired SFN resistance involves aberrant signaling and expression of Akt, mammalian target of rapamycin (mTOR), and a nutrient-related transcription factor, sterol regulatory element binding protein 1c (SREBP-1c). Furthermore, the PI3K and mTOR inhibitor BEZ235 markedly decreased sCLU expression in HepG2-SR cells. Conclusion: These results suggest that measurement of sCLU serum levels and the sCLU-related NR-index are promising clinical tools for the early prediction of SFN response in HCC. Additionally, sCLU-overexpressing HCC might be susceptible to mTOR inhibition.

Expression and Regulatory Network Analysis of Function of Small Nucleolar RNA Host Gene 4 in Hepatocellular Carcinoma

BACKGROUND AND AIMS

Long non-coding RNA small nucleolar RNA host genes (SNHGs) play a critical role in the occurrence and development of tumors. In this study, we aimed to investigate the role of SNHG4 in hepatocellular carcinoma (HCC) and its underlining mechanism.

METHODS

Datasets were acquired from The Cancer Genome Atlas (TCGA) database. lncLocator 2.0 was used to identify the distribution of SNHG4 in HCC cells. Gene expression, Kaplan-Meier survival, microRNA and transcription factor target analyses were performed with the University of Alabama Cancer (UALCAN) Database, Kaplan-Meier Plotter, LinkedOmics, WebGestalt and gene set enrichment analysis, respectively. Gene Ontology and pathway enrichment analyses and assessment of RNA binding proteins were performed by R software, circlncRNAnet and Encyclopedia of RNA Interactomes (ENCORI). In addition, CirclncRNAnet and ENCORI were used to find the correlation between SNHG4 and important proteins, while the prognostic value was assessed with the Human Protein Atlas database and Kaplan-Meier Plotter.

RESULTS

Expression of SNHG4 in HCC is higher in HCC tissue than in normal healthy liver tissues and is mainly distributed in the nucleus. SNHG4 positively correlated with poor prognosis (p<0.01 for overall survival and recurrence-free survival). Functional enrichment analysis revealed SNHG4 involvement with regulation of ribosomal RNA synthesis and the RNA processing and surveillance pathway. SNHG4 is closely associated with miR-154 and miR-206, transcription factor target E2F family and the signaling pathway for MAPK/ERK and mTOR. U2 auxiliary factor 2 (U2AF2) showed strong correlation with SNHG4, while low-expression of U2AF2 showed good prognosis.

CONCLUSIONS

Based on our findings, we infer SNHG4 may play a role in the formation of HCC via regulation of tumor-related pathways.

The CpG Island-Binding Protein SAMD1 Contributes to an Unfavorable Gene Signature in HepG2 Hepatocellular Carcinoma Cells

The unmethylated CpG island-binding protein SAMD1 is upregulated in many human cancer types, but its cancer-related role has not yet been investigated. Here, we used the hepatocellular carcinoma cell line HepG2 as a cancer model and investigated the cellular and transcriptional roles of SAMD1 using ChIP-Seq and RNA-Seq. SAMD1 targets several thousand gene promoters, where it acts predominantly as a transcriptional repressor. HepG2 cells with SAMD1 deletion showed slightly reduced proliferation, but strongly impaired clonogenicity. This phenotype was accompanied by the decreased expression of pro-proliferative genes, including MYC target genes. Consistently, we observed a decrease in the active H3K4me2 histone mark at most promoters, irrespective of SAMD1 binding. Conversely, we noticed an increase in interferon response pathways and a gain of H3K4me2 at a subset of enhancers that were enriched for IFN-stimulated response elements (ISREs). We identified key transcription factor genes, such as IRF1, STAT2, and FOSL2, that were directly repressed by SAMD1. Moreover, SAMD1 deletion also led to the derepression of the PI3K-inhibitor PIK3IP1, contributing to diminished mTOR signaling and ribosome biogenesis pathways. Our work suggests that SAMD1 is involved in establishing a pro-proliferative setting in hepatocellular carcinoma cells. Inhibiting SAMD1's function in liver cancer cells may therefore lead to a more favorable gene signature.

Identification and Validation of Hub Genes with Poor Prognosis in Hepatocellular Carcinoma by Integrated Bioinformatical Analysis

Background

Hepatocellular carcinoma (HCC) is the reason for the world’s second largest cancer-related death. It is clinically valuable to study the molecular mechanisms of HCC occurrence and development for formulating more effective diagnosis and treatment strategies.

Methods

The five microarray data sets GSE45267, GSE101685, GSE84402, GSE62232 and GSE45267 were downloaded from Gene Expression Omnibus (GEO) database, including 165 HCC tissues and 73 normal tissues. Differential expressed genes (DEGs) between HCC tissues and normal tissues were determined by GEO2R. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and the protein–protein interaction network (PPI) network analysis were employed to identify DEGs and to evaluate the clinical significance in prognosis of HCC.

Results

A total of 152 genes differentially expressed in HCC tissues and normal tissues were identified. GO and KEGG functional enrichment analysis revealed that 39 up-regulated genes were mainly enriched in mitosis, cell cycle and oocyte meiosis, while those down-regulated genes (113) were concentrated in exogenous drug catabolism and the metabolism of cytochrome P450 on exogenous drugs. Totally, 19 hub genes were chosen by PPI network and module analysis and verified by The Cancer Genome Atlas (TCGA) database. Finally, 8 hub genes were selected, including CDK1, CYP2C8, CCNB1, AURKA, CYP2C9, BUB1B, MAD2L1 and TTK, which were associated with the overall survival rate of HCC patients.

Conclusion

This study presented eight target genes connected to the prognosis of HCC patients. Those mainly exists in cell cycle and drug catabolism, which may be latent targets for clinical treatment.

Increased risk of hepatocellular carcinoma in patients with traumatic liver injury: Real-world data from a nationwide population-based study

Hepatocellular carcinoma (HCC) is the sixth most common cancer globally, and liver is one of the most commonly injured organs after blunt abdominal trauma. The traumatic liver injury-HCC risk relationship remains unclear.We extracted data of patients with traumatic liver injury between 2000 and 2013 from Taiwan National Health Insurance Research Database (n = 15,966) and those of age-, gender-, occupation-, and index year-matched individuals without traumatic liver injury from the general population (n = 63,864). Cox proportional hazard models were employed to determine the hazard ratios (HRs) and 95% confidence intervals (CIs) for HCC occurrence in the traumatic liver injury cohort compared with that in the comparison cohort.Patients with traumatic liver injury had an increased HCC risk (adjusted HR 2.13, 95% CI 1.59-2.85); this increased risk was more pronounced within 1 year after injury (adjusted HR 8.84, 95% CI 4.29-18.2). After >1 year of injury, HCC risk remained 1.53-fold higher in patients with traumatic liver injury than in those without traumatic liver injury (95% CI 1.08-2.15).People with traumatic liver injury demonstrate a high HCC risk, particularly within the first year of the injury.

Design and optimization of cranberry extract loaded bile salt augmented liposomes for targeting of MCP-1/STAT3/VEGF signaling pathway in DMN-intoxicated liver in rats

Cranberry extract (CBE) is a major source of the antioxidant polyphenolics but suffers from limited bioavailability. The goal of this research was to encapsulate the nutraceutical (CBE), into bile salt augmented liposomes (BSALs) as a promising oral delivery system to potentiate its hepatoprotective impact against dimethylnitrosamine (DMN) induced liver injury in rats. The inclusion of bile salt in the liposomal structure can enhance their stability within the gastrointestinal tract and promote CBE permeability. CBE loaded BSALs formulations were fabricated utilizing a (2³) factorial design to explore the impact of phospholipid type (X₁), phospholipid amount (X₂), and sodium glycocholate (SGC) amount (X₃) on BSALs properties, namely; entrapment efficiency percent, (EE%); vesicle size, (VS); polydispersity index; (PDI); zeta potential, (ZP); and release efficiency percent, (RE%). The optimum formulation (F1) exhibited spherical vesicles with EE% of 71.27 ± 0.32%, VS; 148.60 ± 6.46 nm, PDI; 0.38 ± 0.02, ZP; −18.27 ± 0.67 mV and RE%; 61.96 ± 1.07%. Compared to CBE solution, F1 had attenuated DMN-induced hepatic injury, as evidenced by the significant decrease in serum level of ALT, AST, ALP, MDA, and elevation of GSH level, as well as SOD and GPX activities. Furthermore, F1 exhibited an anti-inflammatory character by suppressing TNF-α, MCP-1, and IL-6, as well as downregulation of VEGF-C, STAT-3, and IFN-γ mRNA levels. This study verified that when CBE was integrated into BSALs, F1, its hepatoprotective effect was significantly potentiated to protect the liver against DMN-induced damage. Therefore, F1 could be deliberated as an antioxidant, antiproliferative, and antifibrotic therapy to slow down the progression of hepatic damage.

PIWI-Interacting RNAs (piRNAs): Promising Applications as Emerging Biomarkers for Digestive System Cancer

PIWI-interacting RNAs (piRNAs) are a novel type of small non-coding RNAs (sncRNAs), which are 26–31 nucleotides in length and bind to PIWI proteins. Although piRNAs were originally discovered in germline cells and are thought to be essential regulators for germline preservation, they can also influence gene expression in somatic cells. An increasing amount of data has shown that the dysregulation of piRNAs can both promote and repress the emergence and progression of human cancers through DNA methylation, transcriptional silencing, mRNA turnover, and translational control. Digestive cancers are currently a major cause of cancer deaths worldwide. piRNAs control the expression of essential genes and pathways associated with digestive cancer progression and have been reported as possible biomarkers for the diagnosis and treatment of digestive cancer. Here, we highlight recent advances in understanding the involvement of piRNAs, as well as potential diagnostic and therapeutic applications of piRNAs in various digestive cancers.

Novel FLT3/AURK multikinase inhibitor is efficacious against sorafenib-refractory and sorafenib-resistant hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is the sixth most common type of cancer and has a high mortality rate worldwide. Sorafenib is the only systemic treatment demonstrating a statistically significant but modest overall survival benefit. We previously have identified the aurora kinases (AURKs) and FMS-like tyrosine kinase 3 (FLT3) multikinase inhibitor DBPR114 exhibiting broad spectrum anti-tumor effects in both leukemia and solid tumors. The purpose of this study was to evaluate the therapeutic potential of DBPR114 in the treatment of advanced HCC.

Methods

Human HCC cell lines with histopathology/genetic background similar to human HCC tumors were used for in vitro and in vivo studies. Human umbilical vein endothelial cells (HUVEC) were used to evaluate the drug effect on endothelial tube formation. Western blotting, immunohistochemical staining, and mRNA sequencing were employed to investigate the mechanisms of drug action. Xenograft models of sorafenib-refractory and sorafenib-acquired resistant HCC were used to evaluate the tumor response to DBPR114.

Results

DBPR114 was active against HCC tumor cell proliferation independent of p53 alteration status and tumor grade in vitro. DBPR114-mediated growth inhibition in HCC cells was associated with apoptosis induction, cell cycle arrest, and polyploidy formation. Further analysis indicated that DBPR114 reduced the phosphorylation levels of AURKs and its substrate histone H3. Moreover, the levels of several active-state receptor tyrosine kinases were downregulated by DBPR114, verifying the mechanisms of DBPR114 action as a multikinase inhibitor in HCC cells. DBPR114 also exhibited anti-angiogenic effect, as demonstrated by inhibiting tumor formation in HUVEC cells. In vivo, DBPR114 induced statistically significant tumor growth inhibition compared with the vehicle control in multiple HCC tumor xenograft models. Histologic analysis revealed that the DBPR114 treatment reduced cell proliferation, and induced apoptotic cell death and multinucleated cell formation. Consistent with the histological findings, gene expression analysis revealed that DBPR114-modulated genes were mostly related to the G2/M checkpoint and mitotic spindle assembly. DBPR114 was efficacious against sorafenib-intrinsic and -acquired resistant HCC tumors. Notably, DBPR114 significantly delayed posttreatment tumor regrowth and prolonged survival compared with the regorafenib group.

Conclusion

Our results indicated that targeting AURK signaling could be a new effective molecular-targeted agent in the treatment of patients with HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-022-00788-0.

Autophagy Modulation and Cancer Combination Therapy: A Smart Approach in Cancer Therapy

The autophagy pathway is the process whereby cells keep cellular homeostasis and respond to stress via recycling their damaged cellular proteins, organelles, and other cellular components. In the context of cancer, autophagy is a dual-edge sword pro- and anti-tumorigenic role depending on the oncogenic context and stage of tumorigenesis. Cancer cells have a higher dependency on autophagy compared with normal cells because of cellular damages and high demands for energy. The carbon, nitrogen, and molecular oxygen are building blocks for highly proliferative cancer cells which extremely depend on glutaminolysis and aerobic glycolysis; when a cancer cell is restricted to glucose and glutamine, it initiates to activate a stress response pathway using autophagy. Oncogenic tyrosine kinases (OncTKs) and receptor tyrosine kinases (RTKs) activation result in autophagy modulation through activation of the PI3K/AKT/mTORC1 and RAS/MAPK signaling pathways. Targeted inhibition of tyrosine kinases (TKs) and RTKs have recently been considered as cancer therapy but drug resistance and cancer relapse continue to be a major limitation of tyrosine kinase inhibitors (TKIs). Manipulation of autophagy pathway along with TKIs may be a promising strategy to circumvent unknown existing drug-resistance mechanisms that may emerge in a treated patient. In this way, clinical trials are ongoing to modulate autophagy to treat cancer. This review aims to summarize the combination therapy of autophagy affecting compounds with anticancer drugs which target cell signaling pathways, metabolism mechanisms, and epigenetics modification to improve therapeutic efficacy against cancers.

Role of lncRNA LINC01194 in hepatocellular carcinoma via the miR-655-3p/SMAD family member 5 axis

Long non-coding RNAs (lncRNAs) are involved in developing hepatocellular carcinoma (HCC). The present study explored the role of lncRNA LINC01194, which is upregulated in HCC tissues and might be a vital regulator in HCC progression. Levels of LINC01194, microRNA (miR)-655-3p, and SMAD family member 5 (SMAD5) were assessed using reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). The bioactivity of Huh-7 cells was assessed using cell counting kit-8 and transwell assays and flow cytometry. Western blotting was conducted to measure the expression of invasion- and apoptosis-related proteins. The relationships between lncRNA LINC01194 and miR-655-3p, and miR-655-3p and SMAD5 were predicted using StarBase and TargetScan, and further verified using a dual-luciferase reporter assay. LINC01194 was overexpressed in HCC cells and in clinical samples. ILINC01194 silencing suppressed proliferation and migration; however, it promoted apoptosis in HCC cell lines. We also confirmed that miR-655-3p could bind to LINC01194, and miR-655-3p was downregulated in HCC. The upregulation of miR-655-3p suppressed HCC cell invasion and migration, and enhanced the number of apoptotic cells. SMAD5, which was overexpressed in HCC cell lines, was directly targeted by miR-655-3p. Therefore, LINC01194 promoted HCC development by decreasing miR-655-3p expression and may serve as a promising therapeutic target for HCC patients.

Potential therapeutic strategies to combat HCC

Hepatocellular carcinoma (HCC) is a complex, life threatening and most common neoplasm in the world. HCC tumors are genetically and phenotypically heterogeneous and involve various molecular mechanisms and stimulation of several signaling pathways such as Vascular Endothelial Growth Factor, Epidermal Growth Factor Receptors (EGFR), Insulin growth factor, Ras/extracellular signal-stimulated kinase, mammalian goal of rapamycin (mTOR), c-mesenchymal-epithelial transition factor-1 (c-Met), Hedgehog, Wnt and apoptotic signaling. Lately, in patient's multi-kinase cascade blockers such as sorafenib, selumetinib and regorafenib have increased survival rate of progressive HCC. This development presents a step forward towards the therapy of liver cancer infection and attests that molecular systemic rehabilitations can be useful in HCC treatment. The development of these systemic therapeutic agents has further expanded the research area for surplus molecular mediators to auxiliary increase cure rate of patients. This article reviews the complete consideration of focus on cascades, current enduring clinical tests by means of HCC therapeutic mediators, and imminent prospects in the cure of HCC.

Identification of Novel Micropeptides Derived from Hepatocellular Carcinoma-Specific Long Noncoding RNA

Identification of cancer-specific target molecules and biomarkers may be useful in the development of novel treatment and immunotherapeutic strategies. We have recently demonstrated that the expression of long noncoding (lnc) RNAs can be cancer-type specific due to abnormal chromatin remodeling and alternative splicing. Furthermore, we identified and determined that the functional small protein C20orf204-189AA encoded by long intergenic noncoding RNA Linc00176 that is expressed predominantly in hepatocellular carcinoma (HCC), enhances transcription of ribosomal RNAs and supports growth of HCC. In this study we combined RNA-sequencing and polysome profiling to identify novel micropeptides that originate from HCC-specific lncRNAs. We identified nine lncRNAs that are expressed exclusively in HCC cells but not in the liver or other normal tissues. Here, DNase-sequencing data revealed that the altered chromatin structure plays a key role in the HCC-specific expression of lncRNAs. Three out of nine HCC-specific lncRNAs contain at least one open reading frame (ORF) longer than 50 amino acid (aa) and enriched in the polysome fraction, suggesting that they are translated. We generated a peptide specific antibody to characterize one candidate, NONHSAT013026.2/Linc013026. We show that Linc013026 encodes a 68 amino acid micropeptide that is mainly localized at the perinuclear region. Linc013026-68AA is expressed in a subset of HCC cells and plays a role in cell proliferation, suggesting that Linc013026-68AA may be used as a HCC-specific target molecule. Our finding also sheds light on the role of the previously ignored ’dark proteome’, that originates from noncoding regions in the maintenance of cancer.

A Pleiotropic Role of the Hepatitis B Virus Core Protein in Hepatocarcinogenesis

Chronic hepatitis B virus (HBV) infection is one of the most common factors associated with hepatocellular carcinoma (HCC), which is the sixth most prevalent cancer among all cancers worldwide. However, the pathogenesis of HBV-mediated hepatocarcinogenesis is unclear. Evidence currently available suggests that the HBV core protein (HBc) plays a potential role in the development of HCC, such as the HBV X protein. The core protein, which is the structural component of the viral nucleocapsid, contributes to almost every stage of the HBV life cycle and occupies diverse roles in HBV replication and pathogenesis. Recent studies have shown that HBc was able to disrupt various pathways involved in liver carcinogenesis: the signaling pathways implicated in migration and proliferation of hepatoma cells, apoptosis pathways, and cell metabolic pathways inducing the development of HCC; and the immune system, through the expression and production of proinflammatory cytokines. In addition, HBc can modulate normal functions of hepatocytes through disrupting human host gene expression by binding to promoter regions. This HBV protein also promotes HCC metastasis through epigenetic alterations, such as micro-RNA. This review focuses on the molecular pathogenesis of the HBc protein in HBV-induced HCC.

Extracellular vesicles as a new hope for diagnosis and therapeutic intervention for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer with a high mortality rate. Early diagnosis and treatment before tumor progression into an advanced stage is ideal. The current diagnosis of HCC is mainly based on imaging modalities such as ultrasound, computed tomography, and magnetic resonance imaging. These methods have some limitations including diagnosis in the case of very small tumors with atypical imaging patterns. Extracellular vesicles (EVs) are nanosized vesicles which have been shown to act as an important vector for cell-to-cell communication. In the past decade, EVs have been investigated with regard to their roles in HCC formation. Since these EVs contain biomolecular cargo such as nucleic acid, lipids, and proteins, it has been proposed that they could be a potential source of tumor biomarkers and a vector for therapeutic cargo. In this review, reports on the roles of HCC-derived EVs in tumorigenesis, and clinical investigations using circulating EVs as a biomarker for HCC and their potential diagnostic roles have been comprehensively summarized and discussed. In addition, findings from in vitro and in vivo reports investigating the potential roles of EVs as therapeutic interventions are also presented. These findings regarding the potential benefits of EVs will encourage further investigations and may allow us to devise novel strategies using EVs in the early diagnosis as well as for treatment of HCC in the future.

Lipid response of hepatocellular carcinoma cells to anticancer drug detected on nanostructure-assisted LDI-MS platform

High heterogeneity of hepatocellular carcinoma (HCC) tumor has become an obstacle to select effective therapy for the treatment of HCC patients. Methods that can guide the decision on therapy choice for HCC treatment are highly demanded. Evaluating the drug response of heterogeneous tumor cells at the molecular level can help to reveal the toxicity mechanism of anticancer drugs and provide more information than current cell-based chemosensitivity assays. In the present work, nanostructure-assisted laser desorption/ionization mass spectrometry (NALDI-MS) was used to investigate the lipid response of HCC cells to anticancer drugs. Three types of HCC cells (LM3, Hep G2, Huh7) were treated with sorafenib, doxorubicin hydro-chloride, and cisplatin. We found that the lipid profiles of HCC cells changed a lot after the drug treatment, and the degree of lipid changes was related to the cell viability. Two pairs of fatty acids C16:1/C16:0 and C18:1/C18:0 were found to be strongly related to the viability of HCC cells after drug treatment, and were more sensitive than Methyl-thiazolyl tetrazolium (MTT) assay. Accordingly, they can act as sensitive and comprehensive indexes to evaluate the drug susceptibility of HCC cells. In addition, the peak ratio of several neighboring phospholipids displayed high correlation with drug response of specific cell subtype to specific drug. The ratio of neighboring lipids may be traced back to the activity of enzyme and gene expression which regulate the lipidomic pathway. This method provides drug response of heterogenous tumor cells at molecular level and could be a potential candidate to precise tumor chemosensitivity assay.

Roles of Therapeutic Bioactive Compounds in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is due to poor prognosis and lack of availability of effective treatment. Novel therapeutic strategies will be the fine tuning of intracellular ROS signaling to effectively deprive cells of ROS-induced tumor-promoting events. This review discusses the generation of ROS, the major signaling their modulation in therapeutics. We explore some of the major pathways involved in HCC, which include the VEGF, MAPK/ERK, mTOR, FGF, and Ser/Thr kinase pathways. In this review, we study cornerstone on natural bioactive compounds with their effect on hepatocarcinomas. Furthermore, we focus on oxidative stress and FDA-approved signaling pathway inhibitors, along with chemotherapy and radiotherapy enhancers which with early evidence of success. While more in vivo testing is required to confirm the findings presented here, our findings will aid future nonclinical, preclinical, and clinical studies with these compounds, as well as inspire medicinal chemistry scientists to conduct appropriate research on this promising natural compound and their derivatives.

RNA methyltransferase NSUN2 promotes growth of hepatocellular carcinoma cells by regulating fizzy-related-1 in vitro and in vivo

The aim of the study was to investigate the role of NSUN2 (NOP2/Sun RNA Methyltransferase Family Member 2) in hepatocellular carcinoma (HCC). The expressions of NSUN2 and FZR1 were measured. Cell viability, proliferation, and apoptosis were assessed. HCC xenograft in nude mouse model was established. Tumor weight and volume were examined. Tumor tissues were collected for immunohistochemistry (IHC). TCGA database analysis and clinical sample testing suggested that the transcript levels of NSUN2 and FZR1 were increased in HCC tissues. NSUN2 knockdown inhibited HCC cell viability and proliferation, and promoted cell apoptosis. Moreover, the effects of NSUN2 could be countered by overexpressing FZR1. In animal experiment, NSUN2 silencing suppressed tumor growth in nude mice by downregulating FZR1. In conclusion, NSUN2 has a regulatory effect on HCC cell proliferation and apoptosis. NSUN2 knockout could inhibit cellular processes in HCC and tumor growth, likely via FZR1 inhibition. This finding has not only revealed the role of NSUN2 in HCC growth, but also suggests a promising target for HCC treatment.

Glycogen accumulation and phase separation drives liver tumor initiation

Glucose consumption is generally increased in tumor cells to support tumor growth. Interestingly, we report that glycogen accumulation is a key initiating oncogenic event during liver malignant transformation. We found that glucose-6-phosphatase (G6PC) catalyzing the last step of glycogenolysis is frequently downregulated to augment glucose storage in pre-malignant cells. Accumulated glycogen undergoes liquid-liquid phase separation, which results in the assembly of the Laforin-Mst1/2 complex and consequently sequesters Hippo kinases Mst1/2 in glycogen liquid droplets to relieve their inhibition on Yap. Moreover, G6PC or another glycogenolysis enzyme-liver glycogen phosphorylase (PYGL) deficiency in both human and mice results in glycogen storage disease along with liver enlargement and tumorigenesis in a Yap-dependent manner. Consistently, elimination of glycogen accumulation abrogates liver growth and cancer incidence, whereas increasing glycogen storage accelerates tumorigenesis. Thus, we concluded that cancer-initiating cells adapt a glycogen storing mode, which blocks Hippo signaling through glycogen phase separation to augment tumor incidence.

Tetraspanin 5 (TSPAN5), a Novel Gatekeeper of the Tumor Suppressor DLC1 and Myocardin-Related Transcription Factors (MRTFs), Controls HCC Growth and Senescence

Simple Summary

Hepatocellular carcinoma (HCC) ranks second among the leading causes of cancer-related death. Since current therapeutic options are very limited, a deeper understanding of the molecular mechanisms underlying the tumor onset and progression of HCC holds great potential for improved therapeutic options. Although it has been shown that deleted in liver cancer 1 (DLC1) acts as a tumor suppressor whose allele is lost in 50% of liver cancers, alterations in gene expression initiated by DLC1 loss have not yet been the primary focus of liver cancer research. To identify novel gene targets that allow for a personalized medicine approach for HCC therapy, we performed gene expression profiling for HepG2 cells stably expressing DLC1shRNA. We provide evidence that TSPAN5 is required for HCC growth, migration and invasion, and dissected the underlying molecular mechanisms involving myocardin-related transcription factors. Thus, TSPAN5 represents a novel therapeutic target for the treatment of HCC characterized by DLC1 loss.

Abstract

Human hepatocellular carcinoma (HCC) is among the most lethal and common cancers in the human population, and new molecular targets for therapeutic intervention are urgently needed. Deleted in liver cancer 1 (DLC1) was originally identified as a tumor suppressor gene in human HCC. DLC1 is a Rho-GTPase-activating protein (RhoGAP) which accelerates the return of RhoGTPases to an inactive state. We recently described that the restoration of DLC1 expression induces cellular senescence. However, this principle is not amenable to direct therapeutic targeting. We therefore performed gene expression profiling for HepG2 cells depleted of DLC1 to identify druggable gene targets mediating the effects of DLC1 on senescence induction. This approach revealed that versican (VCAN), tetraspanin 5 (TSPAN5) and N-cadherin (CDH2) were strongly upregulated upon DLC1 depletion in HCC cells, but only TSPAN5 affected the proliferation of HCC cells and human HCC. The depletion of TSPAN5 induced oncogene-induced senescence (OIS), mediated by the p16^INK4a/pRb pathways. Mechanistically, silencing TSPAN5 reduced actin polymerization and thereby myocardin-related transcription factor A- filamin A (MRTF-A-FLNA) complex formation, resulting in decreased expression of MRTF/SRF-dependent target genes and senescence induction in vitro and in vivo. Our results identify TSPAN5 as a novel druggable target for HCC.

NLRC5 Deficiency Deregulates Hepatic Inflammatory Response but Does Not Aggravate Carbon Tetrachloride-Induced Liver Fibrosis

The nucleotide-binding leucine-rich repeat-containing receptor (NLR) family protein-5 (NLRC5) controls NF-κB activation and production of inflammatory cytokines in certain cell types. NLRC5 is considered a potential regulator of hepatic fibrogenic response due to its ability to inhibit hepatic stellate activation in vitro. To test whether NLRC5 is critical to control liver fibrosis, we treated wildtype and NLRC5-deficient mice with carbon tetrachloride (CCl4) and assessed pathological changes in the liver. Serum alanine transaminase levels and histopathology examination of liver sections revealed that NLRC5 deficiency did not exacerbate CCl4-induced liver damage or inflammatory cell infiltration. Sirius red staining of collagen fibers and hydroxyproline content showed comparable levels of liver fibrosis in CCl4-treated NLRC5-deficient and control mice. Myofibroblast differentiation and induction of collagen genes were similarly increased in both groups. Strikingly, the fibrotic livers of NLRC5-deficient mice showed reduced expression of matrix metalloproteinase-3 (Mmp3) and tissue inhibitor of MMPs-1 (Timp1) but not Mmp2 or Timp2. Fibrotic livers of NLRC5-deficient mice had increased expression of TNF but similar induction of TGFβ compared to wildtype mice. CCl4-treated control and NLRC5-deficient mice displayed similar upregulation of Cx3cr1, a monocyte chemoattractant receptor gene, and the Cd68 macrophage marker. However, the fibrotic livers of NLRC5-deficient mice showed increased expression of F4/80 (Adgre1), a marker of tissue-resident macrophages. NLRC5-deficient livers showed increased phosphorylation of the NF-κB subunit p65 that remained elevated following fibrosis induction. Taken together, NLRC5 deficiency deregulates hepatic inflammatory response following chemical injury but does not significantly aggravate the fibrogenic response, showing that NLRC5 is not a critical regulator of liver fibrosis pathogenesis.

Regulation on tumor metastasis by Raf kinase inhibitory protein: New insight with reactive oxygen species signaling

Targeted therapy aiming at the metastatic signal pathway, such as that triggered by receptor tyrosine kinase (RTK), for the prevention of tumor progression is promising. However, RTK-based targeted therapy frequently suffered from drug resistance due to the co-expression of multiple growth factor receptors that may raise compensatory secondary signaling and acquired mutations after treatment. One alternative strategy is to manipulate the common negative regulators of the RTK signaling. Among them, Raf kinase inhibitory protein (RKIP) is highlighted and focused on this review. RKIP can associate with Raf-1, thus suppressing the downstream mitogen-activated protein kinase (MAPK) cascade. RKIP also negatively regulates other metastatic signal molecules including NF-κB, STAT3, and NOTCH1. In general, RKIP achieves this task via associating and blocking the activity of the critical molecules on upstream of the aforementioned pathways. One novel RKIP-related signaling involves reactive oxygen species (ROS). In our recent report, we found that PKCδ-mediated ROS generation may interfere with the association of RKIP with heat shock protein 60 (HSP60)/MAPK complex via oxidation of HSP60 triggered by the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate. The departure of RKIP may impact the downstream MAPK in two aspects. One is to trigger the Mt→cytosol translocation of HSP60 coupled with MAPKs. The other is to change the conformation of HSP60, favoring more efficient activation of the associated MAPK by upstream kinases in cytosol. It is worthy of investigating whether various RTKs capable of generating ROS can drive metastatic signaling via affecting RKIP in the same manner.

Targeting intra-viral conserved nucleocapsid (N) proteins as novel vaccines against SARS-CoVs

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the global pandemic of the Coronavirus disease in late 2019 (COVID-19). Vaccine development efforts have predominantly been aimed at 'Extra-viral' Spike (S) protein as vaccine vehicles, but there are concerns regarding 'viral immune escape' since multiple mutations may enable the mutated virus strains to escape from immunity against S protein. The 'Intra-viral' Nucleocapsid (N-protein) is relatively conserved among mutant strains of coronaviruses during spread and evolution. Herein, we demonstrate novel vaccine candidates against SARS-CoV-2 by using the whole conserved N-protein or its fragment/peptides. Using ELISA assay, we showed that high titers of specific anti-N antibodies (IgG, IgG1, IgG2a, IgM) were maintained for a reasonably long duration (> 5 months), suggesting that N-protein is an excellent immunogen to stimulate host immune system and robust B-cell activation. We synthesized three peptides located at the conserved regions of N-protein among CoVs. One peptide showed as a good immunogen for vaccination as well. Cytokine arrays on post-vaccination mouse sera showed progressive up-regulation of various cytokines such as IFN-γ and CCL5, suggesting that TH1 associated responses are also stimulated. Furthermore, vaccinated mice exhibited an elevated memory T cells population. Here, we propose an unconventional vaccine strategy targeting the conserved N-protein as an alternative vaccine target for coronaviruses. Moreover, we generated a mouse monoclonal antibody specifically against an epitope shared between SARS-CoV and SARS-CoV-2, and we are currently developing the First-in-Class humanized anti-N-protein antibody to potentially treat patients infected by various CoVs in the future.

Knockdown of ST6Gal-I expression in human hepatocellular carcinoma cells inhibits their exosome-mediated proliferation- and migration-promoting effects

Abnormal sialylation is a distinctive feature of human hepatocellular carcinoma (HCC) and is closely related to its malignant properties. Exosomes have characteristic protein and lipid composition; however, the results concerning glycoprotein composition and glycosylation are scarce. In this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) identified multiple microvesicle-related sialylated proteins including CD63, a classic marker of exosomes. The silencing of α2,6-sialyltransferase I (ST6Gal-I) significantly reduced the levels of α2,6-sialylated glycoconjugates on CD63 and the surface of HCC-derived exosomes (HCC-exo). And surface glycoconjugates play important roles in exosomes biogenesis and in their interaction with other cells. Compared to exosomes derived from naive HCC cells, α2,6-sialylation degradation abolished both the proliferation-promoting and migration-promoting effects of HCC-exo. Further analysis revealed that the Akt/GSK-3β or JNK1/2 signaling mediates HCC-exo-mediated proliferation in HCC cells, while ST6Gal-I silencing deactivated this pathway. These findings suggest that a loss of α2,6-sialylation decreases HCC progression through the loss of cancer cell-derived exosomes; furthermore, it opens novel perspectives to further explore the functional role of glycans in the biology of exosomes.

Signalling pathways and transcriptional regulators orchestrating liver development and cancer

Liver development is controlled by key signals and transcription factors that drive cell proliferation, migration, differentiation and functional maturation. In the adult liver, cell maturity can be perturbed by genetic and environmental factors that disrupt hepatic identity and function. Developmental signals and fetal genetic programmes are often dysregulated or reactivated, leading to dedifferentiation and disease. Here, we highlight signalling pathways and transcriptional regulators that drive liver cell development and primary liver cancers. We also discuss emerging models derived from pluripotent stem cells, 3D organoids and bioengineering for improved studies of signalling pathways in liver cancer and regenerative medicine.

Expression of Cancer Stem Cell Markers EpCAM and CD90 Is Correlated with Anti- and Pro-Oncogenic EphA2 Signaling in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. Additionally, the efficacy of targeted molecular therapies with multiple tyrosine kinase inhibitors is limited. In this study, we focused on the cellular signaling pathways common to diverse HCC cells and used quantitative reverse phase protein array (RPPA) and statistical analyses to elucidate the molecular mechanisms determining its malignancy. We examined the heterogeneity of 17 liver cancer cell lines by performing cluster analysis of their expression of CD90 and EpCAM cancer stem cell markers. Gaussian mixture model clustering identified three dominant clusters: CD90-positive and EpCAM-negative (CD90+), EpCAM-positive and CD90-negative (EpCAM+) and EpCAM-negative and CD90-negative (Neutral). A multivariate analysis by partial least squares revealed that the former two cell populations showed distinct patterns of protein expression and phosphorylation in the EGFR and EphA2 signaling pathways. The CD90+ cells exhibited higher abundance of AKT, EphA2 and its phosphorylated form at Ser⁸⁹⁷, whereas the EpCAM+ cells exhibited higher abundance of ERK, RSK and its phosphorylated form. This demonstrates that pro-oncogenic, ligand-independent EphA2 signaling plays a dominant role in CD90+ cells with higher motility and metastatic activity than EpCAM+ cells. We also showed that an AKT inhibitor reduced the proliferation and survival of CD90+ cells but did not affect those of EpCAM+ cells. Taken together, our results suggest that AKT activation may be a key pro-oncogenic regulator in HCC.

Association between the HGF/c‑MET signaling pathway and tumorigenesis, progression and prognosis of hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is one of the most aggressive and lethal malignancies with a rising incidence, and is characterized by rapid progression, frequent metastasis, late diagnosis, high postoperative recurrence and poor prognosis. Therefore, novel treatment strategies for HCC, particularly advanced HCC, are urgently required. The hepatocyte growth factor (HGF)/c‑mesenchymal‑epithelial transition receptor (c‑MET) axis is a key signaling pathway in HCC and is strongly associated with its highly malignant features. Available treatments based on HGF/c‑MET inhibition may prolong the lifespan of patients with HCC; however, they do not achieve the desired therapeutic effects. The aim of the present article was to review the basic knowledge regarding the role of the HGF/c‑MET signaling pathway in HCC, and examine the association between the HGF/c‑MET signaling pathway and the tumorigenesis, progression and prognosis of HCC.

Epigenetic Mechanisms Involved in HCV-Induced Hepatocellular Carcinoma (HCC)

Hepatocellular carcinoma (HCC), is the third leading cause of cancer-related deaths, which is largely caused by virus infection. About 80% of the virus-infected people develop a chronic infection that eventually leads to liver cirrhosis and hepatocellular carcinoma (HCC). With approximately 71 million HCV chronic infected patients worldwide, they still have a high risk of HCC in the near future. However, the mechanisms of carcinogenesis in chronic HCV infection have not been still fully understood, which involve a complex epigenetic regulation and cellular signaling pathways. Here, we summarize 18 specific gene targets and different signaling pathways involved in recent findings. With these epigenetic alterations requiring histone modifications and DNA hyper or hypo-methylation of these specific genes, the dysregulation of gene expression is also associated with different signaling pathways for the HCV life cycle and HCC. These findings provide a novel insight into a correlation between HCV infection and HCC tumorigenesis, as well as potentially preventable approaches. Hepatitis C virus (HCV) infection largely causes hepatocellular carcinoma (HCC) worldwide with 3 to 4 million newly infected cases diagnosed each year. It is urgent to explore its underlying molecular mechanisms for therapeutic treatment and biomarker discovery. However, the mechanisms of carcinogenesis in chronic HCV infection have not been still fully understood, which involve a complex epigenetic regulation and cellular signaling pathways. Here, we summarize 18 specific gene targets and different signaling pathways involved in recent findings. With these epigenetic alterations requiring histone modifications and DNA hyper or hypo-methylation of these specific genes, the dysregulation of gene expression is also associated with different signaling pathways for the HCV life cycle and HCC. These findings provide a novel insight into a correlation between HCV infection and HCC tumorigenesis, as well as potentially preventable approaches.

The pattern of gene copy number alteration (CNAs) in hepatocellular carcinoma: an in silico analysis

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of liver cancer that occurs predominantly in patients with previous liver conditions. In the absence of an ideal screening modality, HCC is usually diagnosed at an advanced stage. Recent studies show that loss or gain of genomic materials can activate the oncogenes or inactivate the tumor suppressor genes to predispose cells toward carcinogenesis. Here, we evaluated both the copy number alteration (CNA) and RNA sequencing data of 361 HCC samples in order to locate the frequently altered chromosomal regions and identify the affected genes.

RESULTS

Our data show that the chr1q and chr8p are two hotspot regions for genomic amplifications and deletions respectively. Among the amplified genes, YY1AP1 (chr1q22) possessed the largest correlation between CNA and gene expression. Moreover, it showed a positive correlation between CNA and tumor grade. Regarding deleted genes, CHMP7 (chr8p21.3) possessed the largest correlation between CNA and gene expression. Protein products of both genes interact with other cellular proteins to carry out various functional roles. These include ASH1L, ZNF496, YY1, ZMYM4, CHMP4A, CHMP5, CHMP2A and CHMP3, some of which are well-known cancer-related genes.

CONCLUSIONS

Our in-silico analysis demonstrates the importance of copy number alterations in the pathology of HCC. These findings open a door for future studies that evaluate our results by performing additional experiments.

2-Methoxyestradiol synergizes with Erlotinib to suppress hepatocellular carcinoma by disrupting the PLAGL2-EGFR-HIF-1/2α signaling loop

Erlotinib, an EGFR tyrosine kinase inhibitor has been introduced into cancer chemotherapy. However, the therapeutic effects of erlotinib in hepatocellular carcinoma (HCC) remain vaguely understood. Our previous study found that a hypoxia-mediated PLAGL2-EGFR-HIF-1/2α signaling loop in HCC decreased response to erlotinib. The current study has demonstrated that the combination of erlotinib and 2ME2 exerted synergistic antitumor effects against HCC. Further investigation showed that erlotinib increased the expression level of EGFR, HIF-2α, and PLAGL2, which contributes to the insensitivity of hypoxic HCC cells to erlotinib. The simultaneous exposure to 2ME2 effectively inhibited the expression level of EGFR, HIF-2α, and PLAGL2 that was induced by erlotinib. This contributes to the synergistic effect of the two therapeutic agents. Furthermore, the combination of erlotinib and 2ME2 induced apoptosis and inhibited the stemness of hypoxic HCC cells. Our findings potentially explain the mechanism of HCC insensitivity to erlotinib and provide a new strategy of combining EGFR and HIF1/2α inhibitors for HCC treatment.

Role of FGF15 in Hepatic Surgery in the Presence of Tumorigenesis: Dr. Jekyll or Mr. Hyde?

The pro-tumorigenic activity of fibroblast growth factor (FGF) 19 (FGF15 in its rodent orthologue) in hepatocellular carcinoma (HCC), as well as the unsolved problem that ischemia-reperfusion (IR) injury supposes in liver surgeries, are well known. However, it has been shown that FGF15 administration protects against liver damage and regenerative failure in liver transplantation (LT) from brain-dead donors without tumor signals, providing a benefit in avoiding IR injury. The protection provided by FGF15/19 is due to its anti-apoptotic and pro-regenerative properties, which make this molecule a potentially beneficial or harmful factor, depending on the disease. In the present review, we describe the preclinical models currently available to understand the signaling pathways responsible for the apparent controversial effects of FGF15/19 in the liver (to repair a damaged liver or to promote tumorigenesis). As well, we study the potential pharmacological use that has the activation or inhibition of FGF15/19 pathways depending on the disease to be treated. We also discuss whether FGF15/19 non-pro-tumorigenic variants, which have been developed for the treatment of liver diseases, might be promising approaches in the surgery of hepatic resections and LT using healthy livers and livers from extended-criteria donors.

Loss of PGRMC1 Delays the Progression of Hepatocellular Carcinoma via Suppression of Pro-Inflammatory Immune Responses

Simple Summary

Progesterone receptor membrane component 1 (PGRMC1) and epidermal growth factor receptor (EGFR) are highly expressed in various cancers. Here, we first analyzed two sets of clinical data and found that the levels of PGRMC1 and EGFR in hepatocellular carcinomas (HCCs) were both inversely correlated with the survival of HCC patients. Accordingly, by using a carcinogen-induced mouse model of HCC, we found that Pgrmc1 knockout suppressed HCC development and extended the lifespan of HCC-bearing mice. In the acute setting of high-dose carcinogen administration, Pgrmc1 knockout was associated with increases in hepatic necrosis and decreases in the production of the pro-inflammatory cytokine IL-6. Indeed, silencing of Pgrmc1 in murine macrophages suppressed IL-6 production and NF-κB activity, and this process was significantly mediated by EGFR. Our study shows that Pgrmc1 affects the development of HCCs by regulating the EGFR-mediated inflammatory responses. Pgrmc1 may serve as a biomarker and a therapeutic target of HCC.

Abstract

Pgrmc1 is a non-canonical progesterone receptor related to the lethality of various types of cancer. PGRMC1 has been reported to exist in co-precipitated protein complexes with epidermal growth factor receptor (EGFR), which is considered a useful therapeutic target in hepatocellular carcinoma (HCC). Here, we investigated whether Pgrmc1 is involved in HCC progression. In clinical datasets, PGRMC1 transcription level was positively correlated with EGFR levels; importantly, PGRMC1 level was inversely correlated with the survival duration of HCC patients. In a diethylnitrosamine (DEN)-induced murine model of HCC, the global ablation of Pgrmc1 suppressed the development of HCC and prolonged the survival of HCC-bearing mice. We further found that increases in hepatocyte death and suppression of compensatory proliferation in the livers of DEN-injured Pgrmc1-null mice were concomitant with decreases in nuclear factor κB (NF-κB)-dependent production of interleukin-6 (IL-6). Indeed, silencing of Pgrmc1 in murine macrophages led to reductions in NF-κB activity and IL-6 production. We found that the anti-proinflammatory effect of Pgrmc1 loss was mediated by reductions in EGFR level and its effect was not observed after exposure of the EGFR inhibitor erlotinib. This study reveals a novel cooperative role of Pgrmc1 in supporting the EGFR-mediated development of hepatocellular carcinoma, implying that pharmacological suppression of Pgrmc1 may be a useful strategy in HCC treatment.

Microvascular Venous Invasion in Hepatocellular Carcinoma: Why Do Recurrences Occur?

PURPOSE

Hepatocellular carcinoma is the most common primary cancer of the liver. It is almost always associated with cirrhosis and it is usually diagnosed in later stages of the disease. Furthermore, recurrence rate following liver transplantation ranges between 15 and 30%. The most important factor determining the recurrence is vascular invasion.

METHODS

In this review, the issue of microvascular invasion causing hepatocellular carcinoma recurrence is reviewed. Macroscopic vascular invasion is almost easy to diagnose on radiologic evaluation. However, microscopic vascular invasion is almost always diagnosed with pathologic evaluation. On the other hand, microscopic vascular invasion is associated with early recurrences and reduced disease-free survival. The type of vessel that is invaded determines the nature of the spread of the tumor cells. Invasion of the hepatic venous tributaries leads to systemic metastasis whereas portal venous invasions lead to intrahepatic spread of the tumor. Microscopic vascular invasion should be diagnosed before liver transplantation or liver resection in order to deliver the appropriate therapy to the patients.

RESULTS

Yet, there is no ideal marker to suggest microscopic vascular invasion before any intervention. Markers such as alpha-fetoprotein, des carboxy prothrombin, or gamma-glutamyl transferase have been found to be correlated with microscopic vascular invasion. These parameters are not very efficient to be used in routine clinical practice.

CONCLUSION

Therefore, further research is needed to define ideal marker associated with microscopic vascular invasion.

Spectrophotometric and computational investigations of charge transfer complexes of chloranilic acid with tyrosine kinase inhibitors and application to development of novel universal 96-microwell assay for their determination in pharmaceutical formulations

The tyrosine kinase inhibitors (TKIs) are chemotherapeutic drugs used for targeted therapy of various types of cancer. In literature, there is no existing universal chromogenic reagent used for development of spectrophotometric assay for all TKIs regardless the diversity of their chemical structures. This work discusses, for the first time, the experimental and computational evaluation of chloranilic acid (CLA) as a universal chromogenic reagent for developing a novel 96-microwell spectrophotometric assay (MW-SPA) for TKIs. The reaction of CLA with seven TKIs was examined in different organic solvents of various dielectric constants and polarity indexes. The reaction resulted in an instantaneous formation of intensely purple coloured products with all the investigated TKIs. Spectrophotometric investigations confirmed that the reactions proceeded via the formation of charge-transfer complexes (CTC). The physical parameters (molar absorptivity, molar ratio, association constant and standard free energy) were determined for the CTC of all TKIs. Computational calculations for the relative electron densities on each atom of the TKI molecule and molecular modelling for the CTC were conducted, and the site(s) of interaction on each TKI molecule were determined. Under the optimized conditions, Beer's law correlating the absorbances of the CTC with the concentrations of TKIs were obeyed in the range of 5-500 µg/well with good correlation coefficients (0.9991-0.9998). The limits of detection and quantitation were in the ranges of 1.89-5.09 and 5.74-15.42 µg/well, respectively. The proposed MW-SPA showed high precisions as the values of the relative standard deviations did not exceed 2.01 and 2.45% for the intra- and inter-assay precision, respectively. The accuracy of MW-SPA was proved by recovery studies as the recovery values were in the range of 98.8-103.7%. The proposed MW-SPA was successfully applied for the determination of all TKIs in their bulk forms and pharmaceutical formulations (tablets) with good accuracy and precisions. The proposed MW-SPA is the first assay that can analyse all the TKIs on a single assay system without modifications in the detection wavelength. Additional advantages of the proposed MW-SPA are simple, economic, and more importantly have high throughput. Therefore, the assay can be helpful and beneficial for routine analysis of TKIs in their pharmaceutical formulations in quality control laboratories.

Tspan5 promotes epithelial-mesenchymal transition and tumour metastasis of hepatocellular carcinoma by activating Notch signalling

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide due to a high rate of tumour metastasis and disease recurrence. In physiological conditions, tetraspanins interact with specific partner proteins in tetraspanin-enriched microdomains and regulate their subcellular localization and function. However, the function of Tspan5 in pathological processes, particularly in cancer biology and its clinical significance, are still unclear. Here, we describe that a high expression of Tspan5 is significantly associated with some clinicopathological features including invasive length, vascular invasion, clinical stage and poor overall survival of HCC patients. Alterations of Tspan5 expression by lentivirus transductions in HCC cells demonstrated that Tspan5 promotes wound healing and cell migration in vitro and tumour metastasis of HCC cells in vivo. Mechanistic studies revealed that Tspan5 promoted cell migration and tumour metastasis by increasing the enzymatic maturation of ADAM10 and activating Notch signalling via the increase of the cleavage of the Notch1 receptor catalysed by the γ-secretase complex. Activation of Notch signalling by Tspan5 was shown further to enhance the epithelial-mesenchymal transition (EMT) and actin skeleton rearrangement of tumour cells. In clinical HCC samples, Tspan5 expression is strongly correlated with many key molecules acting in Notch signalling and EMT, highlighting the role of Tspan5 in the regulation of Notch signalling, EMT and tumour metastasis of HCC. Our findings provide new insights into the mechanism of tumour metastasis and disease progression of HCC and may facilitate the development of novel clinical intervention strategies against HCC.