Wnt signaling in liver cancer

Tryptophan fuels MYC-dependent liver tumorigenesis through indole 3-pyruvate synthesis

Cancer cells exhibit distinct metabolic activities and nutritional dependencies compared to normal cells. Thus, characterization of nutrient demands by individual tumor types may identify specific vulnerabilities that can be manipulated to target the destruction of cancer cells. We find that MYC-driven liver tumors rely on augmented tryptophan (Trp) uptake, yet Trp utilization to generate metabolites in the kynurenine (Kyn) pathway is reduced. Depriving MYC-driven tumors of Trp through a No-Trp diet not only prevents tumor growth but also restores the transcriptional profile of normal liver cells. Despite Trp starvation, protein synthesis remains unhindered in liver cancer cells. We define a crucial role for the Trp-derived metabolite indole 3-pyruvate (I3P) in liver tumor growth. I3P supplementation effectively restores the growth of liver cancer cells starved of Trp. These findings suggest that I3P is a potential therapeutic target in MYC-driven cancers. Developing methods to target this metabolite represents a potential avenue for liver cancer treatment.

Machine learning and multi-omics data reveal driver gene-based molecular subtypes in hepatocellular carcinoma for precision treatment

The heterogeneity of Hepatocellular Carcinoma (HCC) poses a barrier to effective treatment. Stratifying highly heterogeneous HCC into molecular subtypes with similar features is crucial for personalized anti-tumor therapies. Although driver genes play pivotal roles in cancer progression, their potential in HCC subtyping has been largely overlooked. This study aims to utilize driver genes to construct HCC subtype models and unravel their molecular mechanisms. Utilizing a novel computational framework, we expanded the initially identified 96 driver genes to 1192 based on mutational aspects and an additional 233 considering driver dysregulation. These genes were subsequently employed as stratification markers for further analyses. A novel multi-omics subtype classification algorithm was developed, leveraging mutation and expression data of the identified stratification genes. This algorithm successfully categorized HCC into two distinct subtypes, CLASS A and CLASS B, demonstrating significant differences in survival outcomes. Integrating multi-omics and single-cell data unveiled substantial distinctions between these subtypes regarding transcriptomics, mutations, copy number variations, and epigenomics. Moreover, our prognostic model exhibited excellent predictive performance in training and external validation cohorts. Finally, a 10-gene classification model for these subtypes identified TTK as a promising therapeutic target with robust classification capabilities. This comprehensive study provides a novel perspective on HCC stratification, offering crucial insights for a deeper understanding of its pathogenesis and the development of promising treatment strategies.

Overexpression of RBM34 Promotes Tumor Progression and Correlates with Poor Prognosis of Hepatocellular Carcinoma

BACKGROUND AND AIMS

Emerging evidence suggests that RNA-binding motif (RBM) proteins are involved in hepatocarcinogenesis and act either as oncogenes or tumor suppressors. The objective of this study was to investigate the role of RBM34, an RBM protein, in hepatocellular carcinoma (HCC).

METHODS

We first examined the expression of RBM34 across cancers. The correlation of RBM34 with clinicopathological features and the prognostic value of RBM34 for HCC was then investigated. Functional enrichment analysis of RBM34-related differentially expressed genes (DEGs) was performed to explore its biological function. RNA sequencing (RNA-seq) was applied to identify downstream genes and pathways affected upon RBM34 knockout. The correlation of RBM34 with immune characteristics was also analyzed. The oncogenic function of RBM34 was examined in in vitro and in vivo experiments.

RESULTS

RBM34 was highly expressed in hepatocellular carcinoma and correlated with poor clinicopathological features and prognosis. RBM34 was positively associated with tumor immune cell infiltration, biomarkers of immune cells, and immune checkpoint expression. A positive correlation was also observed between RBM34, T cell exhaustion, and regulatory T cell marker genes. Knockout of RBM34 significantly inhibited cell proliferation, migration, and xenograft tumor growth, and sensitized HCC cells to sorafenib treatment. RBM34 inhibition reduced FGFR2 expression and affected PI3K-AKT pathway activation in HCC cells.

CONCLUSIONS

Our study suggests that RBM34 may serve as a new prognostic marker and therapeutic target of HCC.

Cancer Metastasis and Treatment Resistance: Mechanistic Insights and Therapeutic Targeting of Cancer Stem Cells and the Tumor Microenvironment

Cancer metastasis and treatment resistance are the main causes of treatment failure and cancer-related deaths. Their underlying mechanisms remain to be fully elucidated and have been attributed to the presence of cancer stem cells (CSCs)-a small population of highly tumorigenic cancer cells with pluripotency and self-renewal properties, at the apex of a cellular hierarchy. CSCs drive metastasis and treatment resistance and are sustained by a dynamic tumor microenvironment (TME). Numerous pathways mediate communication between CSCs and/or the surrounding TME. These include a paracrine renin-angiotensin system and its convergent signaling pathways, the immune system, and other signaling pathways including the Notch, Wnt/β-catenin, and Sonic Hedgehog pathways. Appreciation of the mechanisms underlying metastasis and treatment resistance, and the pathways that regulate CSCs and the TME, is essential for developing a durable treatment for cancer. Pre-clinical and clinical studies exploring single-point modulation of the pathways regulating CSCs and the surrounding TME, have yielded partial and sometimes negative results. This may be explained by the presence of uninhibited alternative signaling pathways. An effective treatment of cancer may require a multi-target strategy with multi-step inhibition of signaling pathways that regulate CSCs and the TME, in lieu of the long-standing pursuit of a 'silver-bullet' single-target approach.

Effects of Berberine on Liver Cancer

Liver cancer, otherwise known as hepatocellular carcinoma, is a chronic disease condition with an excessive deposition and growth of malignant cells in the body. The high incidence and prevalence rates of liver cancer continue to be problems, as well as its poor prognosis and therapeutic limitations involving severe drug adverse reactions linked to the use of synthetic chemotherapeutic compounds. Continuous experimental studies, as well as utilization of pure herbal-based compounds, are essential towards finding more potent cures for liver cancer. Natural bioactive compounds, particularly alkaloids (eg, berberine), have been shown to be highly beneficial in the treatment of various diseases. Berberine (BBR), an isoquinoline alkaloid, is obtained from stem, bark, roots, rhizomes, and leaves of several medicinal plants, including Berberis species. It is commonly synthesized from the benzyltetrahydroisoquinoline system with the incorporation of an additional carbon atom as a bridge. The multiple attributes of BBR involving effective inhibitory and cytotoxic actions against the proliferation of cancer cells have been demonstrated. The use of BBR in experimental studies (in vivo and in vitro) for over a decade for liver cancer treatment has proven to be highly effective, safe, and potent. Until now, the poor solubility of BBR remains one of the contributing factors leading to its minimal clinical bioavailability. Therefore, BBR could serve as a prospective drug candidate in the future towards drug formulation for liver cancer treatment. The relevant information regarding this review was obtained electronically through the use of databases such as PubMed, Google Scholar, Springer, Hindawi, Embase, Web of Science, and China National Knowledge Infrastructure. All the aforementioned databases were searched from 1981 to 2020. This literature represents an update of previous review papers discussing the various positive pharmacological and mechanistic effects (oxidative stress regulation, inflammation reduction, apoptosis activation, overcoming drug resistance, and metastasis inhibition) of BBR for liver cancer treatment, which would be of great significance to drug development and clinical research.

Design, synthesis and evaluation of 4,7-disubstituted 8-methoxyquinazoline derivatives as potential cytotoxic agents targeting β-catenin/TCF4 signaling pathway

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Novel 4,7-disubstituted 8-methoxyquinazoline based derivativesdisrupting β-catenin/TCF4 interactions were synthesized.

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Cytotoxic potencies of these derivatives were found to be comparable with imatinib mesylate against constitutively activated β-catenin/TCF4 signaling cancer cells (IC₅₀ ranged from 5.64 ± 0.68 to 23.18 ±0.45 μM against HCT116 and HepG2 cells).

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Compound (18B) was found to be the most potent compound.

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Compound (18B) induced apoptosis and inhibited cell migration against HCT116 and HepG2 cells.

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Compound (18B) significantly downregulated β-catenin/TCF4 signaling pathway (reduced TOP-luciferase activity), β-catenin and TCF4 protein expression, and mRNA levels of c-MYC and Cyclin D1 (Wnt target genes) against HCT116 cells and showed cytotoxicity against primary human gallbladder cancer cells (IC₅₀ 8.50±1.44).

Overactivation of Wnt/β-catenin signaling by accumulated β-catenin in the nucleus has been shown to play a crucial role in the etiology of cancer. Interaction of β-catenin with Transcription factor 4 (TCF4) is a key step for the activation of Wnt genes in response to upstream signals of the Wnt/β-catenin pathway. Hence, down regulation of Wnt/β-catenin signaling or targeting downstream events by selective β-catenin/TCF4 protein–protein interaction inhibitors could be a potential therapeutic strategy against such cancers. In this study structure-based drug design approach was followed to design novel 4,7-disubstituted 8-methoxyquinazoline-based derivatives which could act as potential cytotoxic agents inhibiting the β-catenin/TCF4 protein–protein interactions. Fifteen compounds possessing 4,7-disubstituted 8-methoxyquinazoline scaffold were synthesized. Cytotoxic potential of the synthesised derivatives were determined against constitutively activated β-catenin/TCF4 signaling pathway cancer cells (HCT116 and HepG2) using the sulforhodamine B assay. The most potent compound (18B) was selected for detailed biological evaluation. Cell morphology, Hoechst 33342 and Annexin V/PI staining were used to detect apoptosis, while inhibition of cell migration was assessed by in vitro wound healing assay against HCT116 and HepG2 cells. Effect on β-catenin/TCF mediated transcriptional activity was assessed by TOPFlash/FOPFlash assay, TCF4 and β-catenin protein expression by immunocytofluorescence, and Wnt target genes (like c-MYC and Cyclin D1) mRNA levels by RT-PCR against HCT116 cells. Cytotoxic potency of the most potential compound (18B) against primary human gallbladder cancer cells was also evaluated. The derivatives showed interactions with active site residues of β-catenin and were capable of hindering the TCF4 binding, thereby disrupting β-catenin/TCF4 interactions. Cytotoxic potencies (IC₅₀) of these derivatives ranged from 5.64 ± 0.68 to 23.18 ± 0.45 μM against HCT116 and HepG2 cells respectively. Compound (18B), the most potent compound among the series, induced apoptosis and inhibited cell migration against HCT116 and HepG2 cells. Mechanistic studies indicated that compound (18B) downregulated β-catenin/TCF4 signaling pathway, β-catenin and TCF4 protein expression, and mRNA levels of c-MYC andCyclin D1 in HCT116 cells and showed cytotoxicity against primary human gallbladder cancer cells with IC₅₀ value of 8.50 ± 1.44 μM. Thus, novel 4,7-disubstituted 8-methoxyquinazoline derivatives were identified as potential cytotoxic agents with potencies comparable to that of imatinib mesylate. Compound (18B) represents a promising lead molecule as anticancer agent against colon, hepatocellular and gallbladder cancers targeting β-catenin/TCF4 signaling pathway.

De novo identification of maximally deregulated subnetworks based on multi-omics data with DeRegNet

Background

With a growing amount of (multi-)omics data being available, the extraction of knowledge from these datasets is still a difficult problem. Classical enrichment-style analyses require predefined pathways or gene sets that are tested for significant deregulation to assess whether the pathway is functionally involved in the biological process under study. De novo identification of these pathways can reduce the bias inherent in predefined pathways or gene sets. At the same time, the definition and efficient identification of these pathways de novo from large biological networks is a challenging problem.

Results

We present a novel algorithm, DeRegNet, for the identification of maximally deregulated subnetworks on directed graphs based on deregulation scores derived from (multi-)omics data. DeRegNet can be interpreted as maximum likelihood estimation given a certain probabilistic model for de-novo subgraph identification. We use fractional integer programming to solve the resulting combinatorial optimization problem. We can show that the approach outperforms related algorithms on simulated data with known ground truths. On a publicly available liver cancer dataset we can show that DeRegNet can identify biologically meaningful subgraphs suitable for patient stratification. DeRegNet can also be used to find explicitly multi-omics subgraphs which we demonstrate by presenting subgraphs with consistent methylation-transcription patterns. DeRegNet is freely available as open-source software.

Conclusion

The proposed algorithmic framework and its available implementation can serve as a valuable heuristic hypothesis generation tool contextualizing omics data within biomolecular networks.

Integration of Adverse Outcome Pathways, Causal Networks and ‘Omics to Support Chemical Hazard Assessment

Several approaches have been used in an attempt to simplify and codify the events that lead to adverse effects of chemicals including systems biology, ‘omics, in vitro assays and frameworks such as the Adverse Outcome Pathway (AOP). However, these approaches are generally not integrated despite their complementary nature. Here we propose to integrate toxicogenomics data, systems biology information and AOPs using causal biological networks to define Key Events in AOPs. We demonstrate this by developing a causal subnetwork of 28 nodes that represents the Key Event of regenerative proliferation – a critical event in AOPs for liver cancer. We then assessed the effects of three chemicals known to cause liver injury and cell proliferation (carbon tetrachloride, aflatoxin B₁, thioacetamide) and two with no known cell proliferation effects (diazepam, simvastatin) on the subnetwork using rat liver gene expression data from the toxicogenomic database Open TG-GATEs. Cyclin D1 (Ccnd1), a gene both causally linked to and sufficient to infer regenerative proliferation activity, was overexpressed after exposures to carbon tetrachloride, aflatoxin B₁ and thioacetamide, but not in exposures to diazepam and simvastatin. These results were consistent with known effects on rat livers and liver pathology of exposed rats. Using these approaches, we demonstrate that transcriptomics, AOPs and systems biology can be applied to examine the presence and progression of AOPs in order to better understand the hazards of chemical exposure.

Silybum marianum total extract, silymarin and silibinin abate hepatocarcinogenesis and hepatocellular carcinoma growth via modulation of the HGF/c-Met, Wnt/β-catenin, and PI3K/Akt/mTOR signaling pathways

Hepatocellular carcinoma (HCC) has been identified as one of the most deadly malignancies with limited therapeutic efficacy worldwide. However, understanding the molecular mechanisms of crosstalk between signaling pathways in HCC and predicting cancer cell responses to targeted therapeutic interventions remain to be challenge. Thus, in this study, we aimed to evaluate the anticancerous efficacy of Silybum marianum total extract (STE), silymarin (Sm), and silibinin (Sb) against experimentally-induced HCC in rats. In vitro investigations were also performed and the anticancer effects against HCC cell lines (HepG2 and Huh7) were confirmed. Wistar rats were given diethylnitrosamine (DEN)/2-acetylaminofluorene (AAF)/carbon tetrachloride (CCl4) and were orally treated with STE (200 mg/kg body weight (bw)), Sm (150 mg/kg bw), and Sb (5 mg/kg bw) every other day from the 1st or 16th week to the 25th week of DEN/AAF/CCl4 injection. Treatment with STE, Sm, and Sb inhibited the growth of cancerous lesions in DEN/AAF/CCl4-treated rats. This inhibition was associated with inhibition of Ki-67 expression and repression of HGF/cMet, Wnt/β-catenin, and PI3K/Akt/mTOR signaling pathways. STE, Sm, and Sb improved liver function biomarkers and tumor markers (AFP, CEA, and CA19.9) and increased total protein and albumin levels in serum. STE, Sm, and Sb treatment was also noted to reduce the hepatic production of lipid peroxides, increase hepatic glutathione content, and induce the activities of hepatic antioxidant enzymes in DEN/AAF/CCl4-treated rats. These results indicate that STE, Sm, and Sb exert anti-HCC effects through multiple pathways, including suppression of Ki-67 expression and HGF/cMet, Wnt/β-catenin, and PI3K/Akt/mTOR pathways and enhancement of antioxidant defense mechanisms.

Super-enhancer-driven lncRNA-DAW promotes liver cancer cell proliferation through activation of Wnt/β-catenin pathway

Aberrant expression of long non-coding RNAs (lncRNAs) has been reported in multiple cancers. However, the underlying mechanisms mediated by super-enhancers remain elusive. Here we sought to define the role of a novel lncRNA termed lncRNA-DAW in tumorigenesis. Our results revealed that lncRNA-DAW was driven by a liver-specific super-enhancer and transcriptionally activated by HNF4G, leading to frequent elevation in hepatocellular carcinoma (HCC) specimens. Ectopic expression of lncRNA-DAW promoted both in vivo and in vitro tumor growth. By using RNA sequencing, Wnt2 was screened out as a downstream effector of lncRNA-DAW. We next found that lncRNA-DAW physically interacted with EZH2, a negative regulator of Wnt2. This interplay subsequently potentiated CDK1-EZH2 interaction, leading to the phosphorylation and ubiquitination of EZH2. The lncRNA-DAW-mediated EZH2 degradation facilitated the de-repression of Wnt2 transcription, which eventually activated the Wnt/β-catenin pathway. Furthermore, we verified that Wnt2 potentiated in vitro and in vivo cancer cell growth by activating the Wnt/β-catenin pathway. Finally, Wnt2 amplification was confirmed as a common event in liver cancer, and the expression of lncRNA-DAW was positively correlated with Wnt2 in HCC specimens. Collectively, we are the first to identify lncRNA-DAW as a novel candidate oncogene in liver cancer, and this lncRNA may serve as a novel clinical diagnosis biomarker for liver cancer.

An Overview of the Genomic Characterization of Hepatocellular Carcinoma

Tumor classifications based on alterations in the genome, epigenome, or proteome have revealed distinct tumor subgroups that are associated with clinical outcomes. Several landmark studies have demonstrated that such classifications can significantly improve patient outcomes by enabling tailoring of therapy to specific alterations in cancer cells. Since cancer cells accumulate numerous alterations in many cancer-related genes, it is a daunting task to find and confirm important cancer-promoting alterations as therapeutic targets or biomarkers that can predict clinical outcomes such as survival and response to treatments. To aid further advances, we provide here an overview of the current understanding of molecular and genomic subtypes of hepatocellular carcinoma (HCC). System-level integration of data from multiple studies and development of new technical platforms for analyzing patient samples hold great promise for the discovery of new targets for treatment and correlated biomarkers, leading to personalized medicine for treatment of HCC patients.

Aspirin-induced long-term tumor remission in hepatocellular carcinoma with adenomatous polyposis coli stop-gain mutation: A case report

BACKGROUND

Targeted therapy based on pathway analysis of hepatitis B-related hepatocellular carcinoma (HCC) may be a promising remedy.

CASE SUMMARY

The present case involved an advanced hepatocellular carcinoma (HCC) patient who did not receive local regional therapy and was intolerant to sorafenib. Total RNA extracted from the patient’s tumor tissue was used to obtain the gene mutation profile. The c.3676A>T and c.4402A>T stop-gain mutations in adenomatous polyposis coli (APC) were the most prevalent (42.2% and 35.1%, respectively). MutationMapper analysis indicated that the functional domain of APC was lost in the two APC mutant genes. APC is a major suppressor of the Wnt signaling pathway. Thus, the Wnt pathway was exclusively activated due to APC dysfunction, as other elements of this pathway were not found to be mutated. Aspirin has been reported to suppress the Wnt pathway by inducing β-catenin phosphorylation through the activation of glycogen synthase kinase 3 beta via cyclooxygenase-2 pathway inhibition. Therefore, aspirin was administered to the patient, which achieved four years of disease control.

CONCLUSION

Exclusive mutations of APC of all the Wnt pathway elements could be a therapeutic target in HCC, with aspirin as an effective treatment option.

Proteomic and molecular evidences of Il1rl2, Ric8a, Krt18 and Hsp90b1 modulation during experimental hepatic fibrosis and pomegranate supplementation

The inspection of variations in the proteomic aspects conspire the biomarker discovery in diagnostics of peculiar diseases. Recent developments in high-throughput proteomic techniques have provided leverage in the discovery of biomarkers during the etiology of various diseases. We identified potential biomarkers by utilizing proteomics, bioinformatics and gene expression studies. Meticulous assessment of collagen and hydroxyproline levels along with the glycogen and protein carbonyl levels exhibited deterioration in the N' - Nitrosodiethylamine (NDEA) administered rat livers and subsequent salubrious effect of pomegranate juice. The immunohistochemical inspection of iNOS and nitrite estimation indicated the peccant fibrotic alterations. 2D proteome profiling and MALDI-TOF MS/MS furthered the significant biomarkers to be analyzed for the gene ontology by PANTHER, cluster analysis by DAVID and network simulation by STRING 10.0. Several genes found relevant after MALDI analysis were evaluated by real-time PCR (RTPCR). Our data revealed CYP2b15, HSP70, TRFE, HPT, Il1rl2, Ric8a, Krt18, Hsp90b1 and iNOS as novel biomarkers for the mechanism of pomegranate against liver fibrosis. It can be inferred that NDEA-induced liver fibrosis actuates various biological pathways by the identified biomarkers and pomegranate juice modifies them.

Integrin Linked Kinase (ILK) and its Role in Liver Pathobiology

Integrin linked kinase (ILK) is a vital signaling protein ubiquitously expressed throughout the body. It binds to intracellular integrins to help promote signaling related to cell adhesion, apoptosis, proliferation, migration, and a plethora of other common cellular functions. In this review, ILKs role in the liver is detailed. Studies have shown ILK to be a major participant in hepatic ECM organization, liver regeneration, insulin resistance, and hepatocellular carcinoma.

An oncolytic adenovirus delivering TSLC1 inhibits Wnt signaling pathway and tumor growth in SMMC-7721 xenograft mice model

Tumor suppressor in lung cancer-1 (TSLC1) was first identified as a tumor suppressor for lung cancer, and frequently downregulated in various types of cancers including hepatocellular carcinoma (HCC). The Wnt pathway plays a critical role in tumorigenesis, migration, and invasion in HCC. However, the function of TSLC1 in modulating Wnt signaling in HCC is unclear. In this study, we evaluated the effect of TSLC1-armed oncolytic adenovirus (S24-TSLC1) on the Wnt/β-catenin pathway, cell viability, invasion and migration abilities of HCC in vitro and the growth of SMMC-7721-xenografted tumor in mice model. We detected the expression of TSLC1 in tumor samples and HCC cell lines. The results showed that TSLC1 expression was low in HCC, but high in pericarcinomatous tissue and normal cells, which implied that TSLC1 is a tumor suppressor of liver cancer. S24-TSLC1 exhibited an antitumor effect on HCC cell growth in vitro, but did little damage to normal liver cells. Overexpression of TSLC1 downregulated the transcriptional activity of TCF4/β-catenin and inhibited the mRNA or protein expression of Wnt target genes cyclinD1 and c-myc. S24-TSLC1 also inhibited the invasion and migration of HCC cells. Animal experiments further confirmed that S24-TSLC1 significantly inhibited tumor growth of the SMMC-7721-xenografted tumor. In conclusion, TSLC1 could downregulate the Wnt signal pathway and suppress HCC cell growth, migration and invasion, suggesting that S24-TSLC1 may be a potent antitumor agent for future clinical trials in liver cancer treatment.

Unique Features of Hepatitis B Virus-Related Hepatocellular Carcinoma in Pathogenesis and Clinical Significance

Simple Summary

Hepatitis B virus (HBV) infection is the major risk factor for hepatocellular carcinoma (HCC). Understanding the unique features for HBV-induced HCC can shed new light on the unmet needs in its early diagnosis and effective therapy. During decades of chronic hepatitis B, hepatocytes undergoing repeated damage and regeneration accumulate genetic changes predisposing to HCC development. In addition to traditional mutations in viral and cellular oncogenes, HBV integration into the cell chromosomes is an alternative genetic change contributing to hepatocarcinogenesis. A striking male dominance in HBV-related HCC further highlights an interaction between androgen sex hormone and viral factors, which contributes to the gender difference via stimulating viral replication and activation of oncogenes preferentially in male patients. Meanwhile, a novel circulating tumor biomarker generated by HBV integration shows great potential for the early diagnosis of HCC. These unique HBV-induced hepatocarcinogenic mechanisms provide new insights for the future development of superior diagnosis and treatment strategies.

Abstract

Hepatitis B virus (HBV) infection is one of the important risk factors for hepatocellular carcinoma (HCC) worldwide, accounting for around 50% of cases. Chronic hepatitis B infection generates an inflammatory microenvironment, in which hepatocytes undergoing repeated cycles of damage and regeneration accumulate genetic mutations predisposing them to cancer. A striking male dominance in HBV-related HCC highlights the influence of sex hormones which interact with viral factors to influence carcinogenesis. HBV is also considered an oncogenic virus since its X and surface mutant proteins showed tumorigenic activity in mouse models. The other unique mechanism is the insertional mutagenesis by integration of HBV genome into hepatocyte chromosomes to activate oncogenes. HCC survival largely depends on tumor stages at diagnosis and effective treatment. However, early diagnosis by the conventional protein biomarkers achieves limited success. A new biomarker, the circulating virus–host chimera DNA from HBV integration sites in HCC, provides a liquid biopsy approach for monitoring the tumor load in the majority of HBV–HCC patients. To maximize the efficacy of new immunotherapies or molecular target therapies, it requires better classification of HCC based on the tumor microenvironment and specific carcinogenic pathways. An in-depth study may benefit both the diagnosis and treatment of HBV-related HCC.

Wnt8B, transcriptionally regulated by ZNF191, promotes cell proliferation of hepatocellular carcinoma via Wnt signaling

Dysregulation of wingless‐type (Wnt) signaling is implicated in hepatocellular carcinoma (HCC). Wnt family member 8B (Wnt8B), one of the canonical Wnt ligands, is implicated in oncogenesis. However, the role of Wnt8B in human HCCs and its transcriptional regulation mechanism are presently unknown . Here, we report that Wnt8B expression was frequently increased in HCCs and was significantly associated with poorer patient prognosis. Wnt8B knockdown suppresses HCC cell growth both in vitro and in vivo via inhibiting the canonical Wnt signaling. Zinc finger transcription factor 191 (ZNF191) can positively regulate Wnt8B mRNA and protein expression, and promoter luciferase assay indicated that ZNF191 can increase the transcription activity of the 2‐Kbps WNT8B promoter. Chromatin immunoprecipitation‐qPCR and electrophoretic mobility shift assay showed that ZNF191 protein directly binds to the WNT8B promoter, and the binding sites are at nt‐1491(ATTAATT) and nt‐1178(ATTCATT). Moreover, Wnt8B contributes to the effect of ZNF191 on cell proliferation, and Wnt8B expression correlates positively with ZNF191 in human HCCs. Our findings suggested that Wnt8B, directly transcriptionally regulated by ZNF191, plays a pivotal role in HCC proliferation via the canonical Wnt pathway and may serve as a new prognostic biomarker and a potential therapeutic target for HCC patients.

Targeting Liver Cancer Stem Cells: An Alternative Therapeutic Approach for Liver Cancer

The first report of cancer stem cell (CSC) from Bruce et al. has demonstrated the relatively rare population of stem-like cells in acute myeloid leukemia (AML). The discovery of leukemic CSCs prompted further identification of CSCs in multiple types of solid tumor. Recently, extensive research has attempted to identity CSCs in multiple types of solid tumors in the brain, colon, head and neck, liver, and lung. Based on these studies, we hypothesize that the initiation and progression of most malignant tumors rely largely on the CSC population. Recent studies indicated that stem cell-related markers or signaling pathways, such as aldehyde dehydrogenase (ALDH), CD133, epithelial cell adhesion molecule (EpCAM), Wnt/β-catenin signaling, and Notch signaling, contribute to the initiation and progression of various liver cancer types. Importantly, CSCs are markedly resistant to conventional therapeutic approaches and current targeted therapeutics. Therefore, it is believed that selectively targeting specific markers and/or signaling pathways of hepatic CSCs is an effective therapeutic strategy for treating chemotherapy-resistant liver cancer. Here, we provide an overview of the current knowledge on the hepatic CSC hypothesis and discuss the specific surface markers and critical signaling pathways involved in the development and maintenance of hepatic CSC subpopulations.

Regulation of Wnt Signaling through Ubiquitination and Deubiquitination in Cancers

The Wnt signaling pathway plays important roles in embryonic development, homeostatic processes, cell differentiation, cell polarity, cell proliferation, and cell migration via the β-catenin binding of Wnt target genes. Dysregulation of Wnt signaling is associated with various diseases such as cancer, aging, Alzheimer’s disease, metabolic disease, and pigmentation disorders. Numerous studies entailing the Wnt signaling pathway have been conducted for various cancers. Diverse signaling factors mediate the up- or down-regulation of Wnt signaling through post-translational modifications (PTMs), and aberrant regulation is associated with several different malignancies in humans. Of the numerous PTMs involved, most Wnt signaling factors are regulated by ubiquitination and deubiquitination. Ubiquitination by E3 ligase attaches ubiquitins to target proteins and usually induces proteasomal degradation of Wnt signaling factors such as β-catenin, Axin, GSK3, and Dvl. Conversely, deubiquitination induced by the deubiquitinating enzymes (DUBs) detaches the ubiquitins and modulates the stability of signaling factors. In this review, we discuss the effects of ubiquitination and deubiquitination on the Wnt signaling pathway, and the inhibitors of DUBs that can be applied for cancer therapeutic strategies.

Cancer Stem Cell Functions in Hepatocellular Carcinoma and Comprehensive Therapeutic Strategies

Hepatocellular carcinoma (HCC) is a significant cause of cancer-related mortality owing to resistance to traditional treatments and tumor recurrence after therapy, which leads to poor therapeutic outcomes. Cancer stem cells (CSC) are a small subset of tumor cells with the capability to influence self-renewal, differentiation, and tumorigenesis. A number of surface markers for liver cancer stem cell (LCSC) subpopulations (EpCAM, CD133, CD44, CD13, CD90, OV-6, CD47, and side populations) in HCC have been identified. LCSCs play critical roles in regulating HCC stemness, self-renewal, tumorigenicity, metastasis, recurrence, and therapeutic resistance via genetic mutations, epigenetic disruption, signaling pathway dysregulation, or alterations microenvironment. Accumulating studies have shown that biomarkers for LCSCs contribute to diagnosis and prognosis prediction of HCC, supporting their utility in clinical management and development of therapeutic strategies. Preclinical and clinical analyses of therapeutic approaches for HCC using small molecule inhibitors, oncolytic measles viruses, and anti-surface marker antibodies have demonstrated selective, efficient, and safe targeting of LCSC populations. The current review focuses on recent reports on the influence of LCSCs on HCC stemness, tumorigenesis, and multiple drug resistance (MDR), along with LCSC-targeted therapeutic strategies for HCC.

Assessment of liver cancer biomarkers

Liver cancer is the third cause of cancer-related deaths in the world. It is primarily divides into two main types, namely hepatocellular carcinoma (HC) and cholangiocarcinoma (IC). Due to the increasing number of patients with liver cancer and the high mortality rate, early diagnosis of the disease can be helpful in treatment, but most patients are diagnosed atlate stages of HC. The aim of this study is to screen and provide an overview on candidate biomarkers related to primary liver cancer to introduce the critical ones. In this study, various biomarkers related to the diagnosis of primary liver cancer have been studied. Accordingly, biomarkers are divided into different groups as blood biomarkers classified as serum and plasma biomarkers, tissue biomarkers, microRNA biomarkers, proteomic biomarkers and altered genes. Previous researches have focused on liver cells and bile ducts, the surround cellular environment, how cells differentiate, and the types of genes expressed in liver cancer. Some even have focused on the origin of tumor cells and how they differentiate and develop. In all these studies, the expression of specific proteins and genes in liver cancer has been considered. Based on available sources, biomarkers can be considered as candidates to diagnose and prognosis of various types of primary liver cancer, from sources such as blood, tissue, mic-RNA, proteome and genes. However, more investigations are required to introduce a biomarker for precise detection of early liver cancer.

Salinomycin and its derivatives as potent RET transcriptional inhibitors for the treatment of medullary thyroid carcinoma

Rearranged during transfection kinase (RET) is a validated molecular target in medullary thyroid cancer (MTC), as activating mutations in RET are often associated with the development of MTC. The present study reports the first preclinical characterization of salinomycin and selected analogs as potent RET transcriptional inhibitors. Reverse transcription‑PCR and immunoblotting revealed that salinomycin profoundly decreased RET expression in the TT human MTC cell line by inhibiting RET transcription. Moreover, salinomycin resulted in remarkable anti‑proliferative activity against MTC that is driven by RET (gain of function mutation) by selectively inhibiting the intracellular PI3K/Akt/mTOR signaling pathway. Also, flow cytometry and fluorescence‑activated cell sorting showed that salinomycin induces G1 phase arrest and apoptosis by reducing the expression of retinoblastoma protein, E2F1, cyclin D and CDK4. The structure‑activity relationship of salinomycin was investigated in this study. Some of the salinomycin derivatives showed the ability to reduce RET expression where others fail to alter RET expression. These results suggest that the RET‑suppressing effect of salinomycin may be largely attributed to disruption of the Wnt pathway, presumably through interference with the ternary LRP6‑Frizzled‑Wnt complex. Furthermore, these findings support the further preclinical evaluation of salinomycin and its analogs as a promising new class of therapeutic agents for the improved treatment of MTC.

Association of iRhom1 and iRhom2 expression with prognosis in patients with cervical cancer and possible signaling pathways

Several proteins in the iRhom family function as oncogenic regulators in certain cancers. However, the function of these proteins in cervical cancer (CC) is unknown. The relationship of iRhom1 and iRhom2 expression with the clinicopathological features and prognosis of patients with CC was investigated, and their possible molecular mechanisms were examined using in vitro experiments. The expression of iRhom1 and iRhom2 in CC samples of 83 patients was determined by immunohistochemistry (IHC), and the associations of their expression with the clinicopathological features of patients were determined. The relationship of iRhom1, iRhom2, and Ki-67 expression with survival rates was determined using Kaplan-Meier analysis and Cox regression analyses. HeLa cells were analyzed using MTT assays, cell cycle analysis, and apoptosis assays. The results revealed that CC tissues had higher levels of iRhom1 and iRhom2 than adjacent normal tissues. Increased expression of iRhom1, iRhom2, and K-i67 was significantly associated with tumor stage, size, and parametrium invasion. High expression of iRhom1, iRhom2 and Ki-67 was correlated with poor outcomes. Cancer stage and iRhom2 expression were independent prognostic indicators of CC. Knockdown of iRhom1 and iRhom2 in HeLa cells inhibited cell proliferation, promoted the G1 phase and relieved S-phase arrest, and induced apoptosis. Genomic microarray analysis indicated that iRhom2 knockdown altered several pathways with roles in oncogenesis, including the expression of five genes in the Wnt/β-catenin pathway. Western blotting in HeLa cells revealed that iRhom1 knockdown significantly suppressed the expression of β-catenin, Myc, p-EGFR and TGFBR2, and increased the expression of FAS; iRhom2 knockdown significantly suppressed the expression of β-catenin, GSK3β, p-EGFR and Myc. These results were consistent with the genomic microarray data. Collectively, the results indicated that iRhom1 and iRhom2 may function as oncogenes in CC and are potential therapeutic targets.

HNF4α-Deficient Fatty Liver Provides a Permissive Environment for Sex-Independent Hepatocellular Carcinoma

The incidence of hepatocellular carcinoma (HCC) is on the rise worldwide. Although the incidence of HCC in males is considerably higher than in females, the projected rates of HCC incidence are increasing for both sexes. A recently appreciated risk factor for HCC is the growing problem of nonalcoholic fatty liver disease, which is usually associated with obesity and the metabolic syndrome. In this study, we showed that under conditions of fatty liver, female mice were more likely to develop HCC than expected from previous models. Using an inducible knockout model of the tumor-suppressive isoform of hepatocyte nuclear factor 4 alpha ("P1-HNF4α") in the liver in combination with prolonged high fat (HF) diet, we found that HCC developed equally in male and female mice as early as 38 weeks of age. Similar sex-independent HCC occurred in the "STAM" model of mice, in which severe hyperglycemia and HF feeding results in rapid hepatic lipid deposition, fibrosis, and ultimately HCC. In both sexes, reduced P1-HNF4α activity, which also occurs under chronic HF diet feeding, increased hepatic lipid deposition and produced a greatly augmented circadian rhythm in IL6, a factor previously linked with higher HCC incidence in males. Loss of HNF4α combined with HF feeding induced epithelial-mesenchymal transition in an IL6-dependent manner. Collectively, these data provide a mechanism-based working hypothesis that could explain the rising incidence of aggressive HCC. SIGNIFICANCE: This study provides a mechanism for the growing incidence of hepatocellular carcinoma in both men and women, which is linked to nonalcoholic fatty liver disease.

Piplartine suppresses proliferation and invasion of hepatocellular carcinoma by LINC01391-modulated Wnt/β-catenin pathway inactivation through ICAT

Although piplartine is regarded as an anticancer agent, the relationship between long noncoding RNAs (lncRNAs), which are involved in various diseases (e.g., tumors) and piplartine in hepatocellular carcinoma (HCC) remains unclear. We identified LINC01391 using microarray analysis and validated its expression by qRT-PCR. Functional assays were applied to evaluate the biological effects of LINC01391 and inhibitory of β-catenin and T-cell factor (ICAT) on HepG2 and SMMC-7721 cells. The binding relationship between LINC01391 and ICAT was determined by RNA pull-down and RNA immunoprecipitation (RIP). Results showed that piplartine attenuated cell proliferation and invasion but promoted cell apoptosis. Upregulation of LINC01391 induced by piplartine inhibited HCC cell proliferation, invasion in vitro, and tumor growth in vivo. LINC01391 interacted with ICAT and promoted its inhibitory effect on the Wnt/β-catenin pathway, as enhanced interaction between β-catenin and ICAT, and dampened interaction of β-catenin and TCF/LEF were induced by overexpression of LINC01391. Knockdown of ICAT also promoted cell proliferation in vitro and tumor growth in vivo. Our study supported a role for piplartine and LINC01391 in HCC treatment. We found that LINC01391 inhibited the Wnt/β-catenin pathway and suppressed tumor growth via ICAT.

Synergistic effect of berberine and HMQ1611 impairs cell proliferation and migration by regulating Wnt signaling pathway in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a biologically complex disease. Combination chemotherapy is a good strategy after surgery treatment. In this study, we report that berberine combined with HMQ1611 (BCH) had a good synergistic effect on the HCC. Our findings concluded that BCH showed good inhibition on the HCC proliferation and colony formation, which attributed to cell cycle arrest by BCH at G1 phase through impairing the expression of cyclinD1, cyclinE, and cdc2 and downregulated the phosphorylation of Akt, mTOR, and ERK. Moreover, BCH negatively regulated Wnt signaling pathway by upregulating the Axin and inhibiting the nuclear translocation of β-catenin. BCH suppressed the phosphorylation of LRP5/6, GSK3β, the expression of Wnt5a, Frizzled8, CK1, and APC, as well as the nucleus protein included MMP2, MMP3, MMP9, and c-myc. The above data of Wnt signaling regulators contributed to inhibition by BCH on cell migration. In vivo studies, BCH significantly suppressed the growth of SMMC-7721 xenograft tumors through downregulating Ki67 and β-catenin, as well as upregulating Axin and p-β-catenin. In conclusion, the results revealed that BCH exhibited potential antitumor activities against human liver cancer in vitro and in vivo, and the potential mechanism underlying these activities depended on the inhibition of the Wnt/β-catenin signaling pathway.

HMQ-T-F5 (1-(4-(2-aminoquinazolin-7-yl)phenyl)-3-(2‑bromo‑5- (trifluoromethoxy)phenyl) thiourea) suppress proliferation and migration of human cervical HeLa cells via inhibiting Wnt/β-catenin signaling pathway

BACKGROUND

Drug therapy plays an important role in the treatment of cervical cancer, which is one of the most common solid tumors in women. Therefore, it is important to seek more effective and less toxic therapies.

PURPOSE

The aim of this study is to investigate the therapeutic potential of HMQ-T-F5 (1-(4-(2-aminoquinazolin-7-yl)phenyl)-3-(2‑bromo‑5-(trifluoromethoxy) phenyl)thiourea) (F5) for cervical cancer and explore the related mechanism.

METHODS

By performing MTT assay, colony formation assay, flow cytometry, wound-healing assay, transwell assay, immunofluorescent staining and siRNA assay, we study the effect of F5 on human cervical HeLa cells. The mechanism of F5 was also investigated.

RESULTS

We found that F5 significantly inhibited HeLa cell proliferation, led to accumulation of cells in the S phase, and induced apoptosis and inhibited migration. Mechanistically, F5 inhibited HeLa cell growth and migration through repressing the expression and nuclear translocation of β-catenin, enhancing Axin expression, inhibiting the phosphorylation of LRP5/6 and GSK3β, as well as downregulating the Wnt downstream targeted proteins. Knockdown of a checkpoint β-catenin by siRNA significantly attenuated HeLa cell proliferation. Furthermore, XAV939, an inhibitor of β-catenin, was used to treat HeLa cells and the results demonstrated that F5 inhibited proliferation and migration via the inhibition of the Wnt/β-catenin pathway.

CONCLUSION

Our findings demonstrated that F5 can target β-catenin potentially and is useful in the treatment of cervical cancer.

HPV-18 E6 Oncoprotein and Its Spliced Isoform E6*I Regulate the Wnt/β-Catenin Cell Signaling Pathway through the TCF-4 Transcriptional Factor

The Wnt/β-catenin signaling pathway regulates cell proliferation and differentiation and its aberrant activation in cervical cancer has been described. Persistent infection with high risk human papillomavirus (HR-HPV) is the most important factor for the development of this neoplasia, since E6 and E7 viral oncoproteins alter cellular processes, promoting cervical cancer development. A role of HPV-16 E6 in Wnt/β-catenin signaling has been proposed, although the participation of HPV-18 E6 has not been previously studied. The aim of this work was to investigate the participation of HPV-18 E6 and E6*I, in the regulation of the Wnt/β-catenin signaling pathway. Here, we show that E6 proteins up-regulate TCF-4 transcriptional activity and promote overexpression of Wnt target genes. In addition, it was demonstrated that E6 and E6*I bind to the TCF-4 (T cell factor 4) and β-catenin, impacting TCF-4 stabilization. We found that both E6 and E6*I proteins interact with the promoter of Sp5, in vitro and in vivo. Moreover, although differences in TCF-4 transcriptional activation were found among E6 intratype variants, no changes were observed in the levels of regulated genes. Furthermore, our data support that E6 proteins cooperate with β-catenin to promote cell proliferation.

Profiling cytochrome P450 family 4 gene expression in human hepatocellular carcinoma

Cytochrome P450 family 4 (CYP4) enzymes are known as microsomal omega (ω)-hydroxylases that metabolize fatty acids, eicosanoids, vitamin D and carcinogens. Thus, CYP4 enzymes may influence tumor development and progression. The aim of the present study was to evaluate the CYP4 expression profile in hepatocellular carcinoma (HCC) and its clinical relevance. The present study obtained CYP4 mRNA expression data for 377 HCC cases from The Cancer Genome Atlas cohort and performed Kaplan‑Meier survival, Gene Ontology functional enrichment, and gene set enrichment analysis (GSEA). In addition, the level of CYP4F2 protein expression was evaluated in matched pairs of HCC and non‑tumor tissue samples and the results were correlated with the clinicopathological characteristics of HCC (n=113). HCC survival analyses indicated better overall survival in patients with high CYP4F2, CYP4F12 and CYP4V2 mRNA expression levels; the results for histological grade and Tumor‑Node‑Metastasis stage supported these results. GSEA revealed high levels of CYP4F2, CYP4F12 and CYP4V2 mRNA expression to be negatively correlated with the expression of cell cycle‑associated genes. CYP4F2 protein expression was higher in non‑neoplastic liver tissue than in HCC tissue and positively correlated with favorable pathological tumor stage (I vs. II‑IV; P=0.022) and was a good independent prognostic factor for overall survival (P=0.004). These results demonstrate that the expression levels of the genes CYP4F2, CYP4F12 and CYPV2 are favorable prognostic factors in HCC and suggest the potential predictive diagnostic and prognostic roles of CYP4F2, CYP4F12 and CYPV2 gene expression in HCC.

Enrichment of cancer stem cells via β-catenin contributing to the tumorigenesis of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is among the deadliest cancers due to its heterogeneity, contributing to chemoresistance and recurrence. Cancer stem-like cells (CSCs) are suggested to play an important role in HCC tumorigenesis. This study investigates the role of Wnt/β-catenin pathway in CSC enrichment and the capabilities of these CSCs in tumor initiation in orthotopic immunocompetent mouse model.

Methods

HCC-CSCs were enriched using established serum-free culture method. Wnt/β-catenin pathway activation and its components were analyzed by western blot and qRT-PCR. The role of β-catenin in enrichment of CSC spheroids was confirmed using siRNA interference. Tumorigenic capabilities were confirmed using orthotopic immunocompetent mouse model by injecting 2 × 10⁶ Hepa1–6 CSC spheroids or control cells in upper left liver lobe.

Results

The serum-free cultured Hepa1–6 cells demonstrated self-renewal, spheroid formation, higher EpCAM expression, increased Hoechst-33342 efflux, and upregulated Wnt/β-catenin signaling. Wnt/β-catenin pathway upregulation was implicated with the downstream targets, i.e., c-MYC, Cyclin-D1, and LEF1. Also, we found that GSK-3β serine-9 phosphorylation increased in Hepa1–6 spheroids. Silencing β-catenin by siRNA reversed spheroid formation phenotype. Mice injected with Hepa1–6 CSC spheroids showed aggressive tumor initiation and growth compared with mice injected with control cells.

Conclusions

Successfully induced Hepa1–6 spheroids were identified with CSC-like properties. Aberrant β-catenin upregulation mediated by GSK-3β was observed in the Hepa1–6 spheroids. The β-catenin mediated CSC enrichment in the induced spheroids possesses the capability of tumor initiation in immunocompetent mice. Our study suggests plausible cell dedifferentiation mediated by β-catenin contributes to CSC-initiated HCC tumor growth in vivo.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4683-0) contains supplementary material, which is available to authorized users.

Bioinformatics functional analysis of let-7a, miR-34a, and miR-199a/b reveals novel insights into immune system pathways and cancer hallmarks for hepatocellular carcinoma

Let-7a, miR-34a, and miR-199 a/b have gained a great attention as master regulators for cellular processes. In particular, these three micro-RNAs act as potential onco-suppressors for hepatocellular carcinoma. Bioinformatics can reveal the functionality of these micro-RNAs through target prediction and functional annotation analysis. In the current study, in silico analysis using innovative servers (miRror Suite, DAVID, miRGator V3.0, GeneTrail) has demonstrated the combinatorial and the individual target genes of these micro-RNAs and further explored their roles in hepatocellular carcinoma progression. There were 87 common target messenger RNAs (p ≤ 0.05) that were predicted to be regulated by the three micro-RNAs using miRror 2.0 target prediction tool. In addition, the functional enrichment analysis of these targets that was performed by DAVID functional annotation and REACTOME tools revealed two major immune-related pathways, eight hepatocellular carcinoma hallmarks-linked pathways, and two pathways that mediate interconnected processes between immune system and hepatocellular carcinoma hallmarks. Moreover, protein-protein interaction network for the predicted common targets was obtained by using STRING database. The individual analysis of target genes and pathways for the three micro-RNAs of interest using miRGator V3.0 and GeneTrail servers revealed some novel predicted target oncogenes such as SOX4, which we validated experimentally, in addition to some regulated pathways of immune system and hepatocarcinogenesis such as insulin signaling pathway and adipocytokine signaling pathway. In general, our results demonstrate that let-7a, miR-34a, and miR-199 a/b have novel interactions in different immune system pathways and major hepatocellular carcinoma hallmarks. Thus, our findings shed more light on the roles of these miRNAs as cancer silencers.

Prognostic impact of the expression of Wnt-signaling proteins in cervical carcinoma FIGO stage I-IV treated with radiotherapy or chemoradiotherapy

Wnt signaling proteins were assessed in patients with primary cervical carcinomas who received chemoradiation. The associations between three Wnt signaling proteins and prognosis were assessed. Specimens from 122 patients with cervical carcinomas (FIGO stage I-IV) were immunohistochemically (IHC) analyzed for β-catenin, APC and axin protein expression. Associations between these Wnt-protein expressions, clinicopathological factors, and clinical outcome data were examined.

Positive IHC staining for the β-catenin protein (cell-membranes, cytoplasm and nuclei) was recorded in 88%, 58% and 5%, respectively. There was a strong association between β-catenin staining of the cell-membranes and prediction of recurrences and prognosis (p = 0. 002). Tumors with > 5% of nuclear β-catenin staining were associated with inferior cancer-specific survival (p = 0.048) compared with no staining. The overall recurrence rate was significantly higher in the group with increased nuclear staining (67%) compared with the group with no staining (33%). Nuclear APC staining of high intensity was associated with a significantly worse cancer-specific survival and increased overall recurrence rate compared to tumors with weak staining. Distant recurrences were recorded in 29% of cases with intense staining and in 14% of cases with low staining.

The Wnt signaling pathway seems to be of importance in the process of cervical oncogenesis. A predictive and prognostic value was found for β-catenin, where strong cell-membrane staining was favorable, and > 5% positive nuclear staining was associated with poorer cancer-specific survival and overall recurrence rate. Nuclear APC staining intensity was also associated with a less favorable prognosis.

miR2Pathway: A novel analytical method to discover MicroRNA-mediated dysregulated pathways involved in hepatocellular carcinoma

MicroRNAs (miRNAs) are small, non-coding RNAs involved in the regulation of gene expression at a post-transcriptional level. Recent studies have shown miRNAs as key regulators of a variety of biological processes, such as proliferation, differentiation, apoptosis, metabolism, etc. Aberrantly expressed miRNAs influence individual gene expression level, but rewired miRNA-mRNA connections can influence the activity of biological pathways. Here, we define rewired miRNA-mRNA connections as the differential (rewiring) effects on the activity of biological pathways between hepatocellular carcinoma (HCC) and normal phenotypes. Our work presented here uses a PageRank-based approach to measure the degree of miRNA-mediated dysregulation of biological pathways between HCC and normal samples based on rewired miRNA-mRNA connections. In our study, we regard the degree of miRNA-mediated dysregulation of biological pathways as disease risk of biological pathways. Therefore, we propose a new method, miR2Pathway, to measure and rank the degree of miRNA-mediated dysregulation of biological pathways by measuring the total differential influence of miRNAs on the activity of pathways between HCC and normal states. miR2Pathway proposed here systematically shows the first evidence for a mechanism of biological pathways being dysregulated by rewired miRNA-mRNA connections, and provides new insight into exploring mechanisms behind HCC. Thus, miR2Pathway is a novel method to identify and rank miRNA-dysregulated pathways in HCC.

Wnt signaling in cervical cancer?

Cervical cancer (CC) is the second most common malignant cancer in women. CC is difficult to diagnose, has a high recurrence rate, and is resistant to systemic therapies; as a result, CC patients have a relatively poor prognosis. One potential link to CC is the Wnt signaling pathway and its downstream effectors, which regulate cell differentiation, proliferation, migration, and fate. The aberrant activation of Wnt signaling is associated with various cancers, including CC. Recent studies have shown that activating or inhibiting the intracellular signal transduction in this pathway can regulate cancer cell growth and viability. This review will summarize the experimental evidence supporting the significance of the Wnt signaling pathway in CC, and will also discuss the current clinical role of Wnt signaling in CC diagnosis, therapy, and prognosis.

Potential diagnostic and prognostic marker dimethylglycine dehydrogenase (DMGDH) suppresses hepatocellular carcinoma metastasis in vitro and in vivo

Key metabolic enzymes regulatethe fluxes of small compounds to provide the basal substrates for cellular architecture and energy. Some of them are reported to be important carcinogenesis- and metastasis-related genes. In our work, we performed RNA-seq for50 pairs of normal-tumor of hepatocellular carcinoma (HCC) samples and found that the expression of dimethylglycine dehydrogenase (DMGDH) is decreased in HCC. The analysis of protein levels with Western blotting and immunohistochemistry also conformed our findings. It is proven to be a valuable biomarker for both diagnosis and prognosis in three independent datasets. Furthermore, we revealed that DMGDH suppresses migration, invasion and metastasis both in vitro and in vivo. By utilizing gene expression microarray for DMGDH, we identified several possible pathways altered in a DMGDH over-expressing cell line. Among these pathways, we noted that the phosphorylation of Akt-308/473 was significantly suppressed when DMGDH was over-expressed. In summary, our work reveals that DMGDH is a potential valuable biomarker for both diagnosis and prognosisfor HCC, and DMGDH gene expression suppresses metastasis through the Akt signaling pathway.

The role of Wnt/β-catenin signaling pathway in melanoma epithelial-to-mesenchymal-like switching: evidences from patients-derived cell lines

Deregulations or mutations of WNT/β-catenin signaling have been associated to both tumour formation and progression. However, contradictory results concerning the role of β-catenin in human melanoma address an open question on its oncogenic nature and prognostic value in this tumour. Changes in WNT signaling pathways have been linked to phenotype switching of melanoma cells between a highly proliferative/non-invasive and a slow proliferative/metastatic condition. We used a novel panel of cell lines isolated from melanoma specimens, at initial passages, to investigate phenotype differences related to the levels and activity of WNT/β-catenin signaling pathway. This in vitro cell system revealed a marked heterogeneity that comprises, in some cases, two distinct tumour-derived subpopulations of cells presenting a different activation level and cellular distribution of β-catenin. In cells derived from the same tumor, we demonstrated that the prevalence of LEF1 (high β-catenin expressing cells) or TCF4 (low β-catenin expressing cells) as β-catenin partner for DNA binding, is associated to the expression of two distinct profiles of WNT-responsive genes. Interestingly, melanoma cells expressing relative low level of β-catenin and an invasive markers signature were associated to the TNF-α-induced pro-inflammatory pathway and to the chemotherapy resistance, suggesting that the co-existence of melanoma subpopulations with distinct biological properties could influence the impact of chemo- and immunotherapy.

Wnt3a expression is associated with poor prognosis of esophageal squamous cell carcinoma

The Wnt signaling pathway is widely implicated in various types of cancer. Canonical Wnt signaling, including Wnt3a, may be a key component of cancer progression or chemoresistance. Consequently, it was hypothesized that Wnt3a expression may be a prognostic factor of esophageal squamous cell carcinoma (ESCC) due to its roles in chemoresistance and tumor progression. The aim of the present study was to investigate the association between Wnt3a expression and prognosis in patients with ESCC. Wnt3a expression was evaluated in resected specimens from 139 patients with thoracic ESCC who were subjected to curative surgery without neoadjuvant therapy in Tokai University Hospital between 2007 and 2009. Samples were assessed using immnohistochemistry. Patients with ESCC were divided into two groups according to the expression of Wnt3a in tumor tissue. The influence of Wnt3a expression on clinicopathological findings and prognosis of ESCC were subsequently investigated. Immnohistologically, 68 cases were Wnt3a-positive in the cytoplasm of cancer cells, whereas 71 cases were negative. Multivariate analysis by Cox proportional hazard model showed the association between pN (HR=3.539, P=0.001), venous invasion (HR=2.798, P=0.012), Wnt3a expression (HR=1.691, P=0.046) and overall survival (OS). OS rate and disease-free survival rate were poorer in Wnt3a-positive group compared with those in the Wnt3a-negative group as indicated by the log-rank test (P=0.012 and P=0.023, respectively). In pathological stages I and II, there was no significant difference in the OS rate between Wnt3a-positive and Wnt3a-negative groups; however, the OS rate of the Wnt3a-positive group was significantly worse than that of Wnt3a-negative group in pathological stage III (log rank test; P=0.017). Wnt3a-positive patients with recurrence had a significantly poorer prognosis compared with Wnt3a-negative patients (log-rank test; P=0.023). The present findings suggested that Wnt3a may be a prognostic factor of ESCC.

Paracrine and autocrine regulation of gene expression by Wnt-inhibitor Dickkopf in wild-type and mutant hepatocytes

Background

Cells are able to communicate and coordinate their function within tissues via secreted factors. Aberrant secretion by cancer cells can modulate this intercellular communication, in particular in highly organised tissues such as the liver. Hepatocytes, the major cell type of the liver, secrete Dickkopf (Dkk), which inhibits Wnt/ β-catenin signalling in an autocrine and paracrine manner. Consequently, Dkk modulates the expression of Wnt/ β-catenin target genes. We present a mathematical model that describes the autocrine and paracrine regulation of hepatic gene expression by Dkk under wild-type conditions as well as in the presence of mutant cells.

Results

Our spatial model describes the competition of Dkk and Wnt at receptor level, intra-cellular Wnt/ β-catenin signalling, and the regulation of target gene expression for 21 individual hepatocytes. Autocrine and paracrine regulation is mediated through a feedback mechanism via Dkk and Dkk diffusion along the porto-central axis. Along this axis an APC concentration gradient is modelled as experimentally detected in liver. Simulations of mutant cells demonstrate that already a single mutant cell increases overall Dkk concentration. The influence of the mutant cell on gene expression of surrounding wild-type hepatocytes is limited in magnitude and restricted to hepatocytes in close proximity. To explore the underlying molecular mechanisms, we perform a comprehensive analysis of the model parameters such as diffusion coefficient, mutation strength and feedback strength.

Conclusions

Our simulations show that Dkk concentration is elevated in the presence of a mutant cell. However, the impact of these elevated Dkk levels on wild-type hepatocytes is confined in space and magnitude. The combination of inter- and intracellular processes, such as Dkk feedback, diffusion and Wnt/ β-catenin signal transduction, allow wild-type hepatocytes to largely maintain their gene expression.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-017-0470-9) contains supplementary material, which is available to authorized users.

Systemic therapy for advanced hepatocellular carcinoma: an update

Advanced hepatocellular carcinoma (HCC) is a deadly disease with few systemic therapeutic options. Sorafenib is the only agent to be FDA approved for the first-line treatment of patients with HCC. This drug increases overall survival (OS) by 3 months compared with placebo (10.7 months with sorafenib vs. 7.7 months with placebo). More recently, the RESORCE trial demonstrated efficacy of regorafenib in the second-line treatment of HCC: OS was increased from 7.8 months with placebo to 10.6 months with regorafenib after patients experienced disease progression on sorafenib. However, there is still an unmet need for effective systemic therapy of patients with advanced HCC. Numerous genetic pathways have been studied along with drugs to target these pathways but, thus far, drugs targeting cell proliferation, metastasis, angiogenesis, and metabolite use have been studied with minimal success. HCC can be divided into two subclasses: proliferative and non-proliferative, each dependent on separate pathways. HCC can be caused by alcoholic cirrhosis, hepatitis C virus (HCV), and hepatitis B virus (HBV); however no etiology-specific therapies have been demonstrated. Immunotherapy is currently being assessed in clinical trials and is demonstrating some efficacy. More research is needed to determine the most essential pathways to target in the war against this deadly cancer.

Influence of polymorphisms in the Wnt/β-catenin pathway genes on hepatocellular carcinoma risk in a Chinese Han population

The Wnt/β-catenin pathway plays a vital role in initiating and sustaining hepatocellular carcinoma (HCC). However, few studies have investigated polymorphisms in the Wnt/β-catenin signaling pathway genes in the Chinese Han population. The aim of the present retrospective study was to investigate the correlations between polymorphisms of the Wnt/β-catenin signaling pathway genes (CTNNB1 and WNT2) and HCC susceptibility, development, and progression.Twenty tagging single nucleotide polymorphisms were chosen from HapMap data and genotyped in 320 patients with HCC, 320 chronic hepatitis B virus (HBV)-infected patients without HCC (N-HCC, including 95 liver cirrhosis, 164 chronic hepatitis B, and 61 asymptomatic HBV carriers), and 320 healthy controls. Associations between polymorphisms in the 2 Wnt/β-catenin signaling pathway genes (CTNNB1 and WNT2) and HCC susceptibility, development, and progression were investigated.Genotype AA (P = 0.002, odds ratio [OR] = 2.524) and allele A (P = 0.0003, OR = 1.613) of the WNT2 rs4730775 polymorphism were associated with HCC susceptibility compared with healthy controls. Genotype GA (P = 0.001, OR = 0.567) and allele A (P = 0.002, OR = 0.652) of rs3864004, and genotype AG (P = 0.0004, OR = 0.495) and allele G (P = 0.001, OR = 0.596) of rs11564475 in the CTNNB1 gene were correlated with HCC compared with N-HCC patients. These findings were consistent in dominant and recessive models. Multidimensionality reduction analysis revealed that interactions among rs3864004, rs11564475, and rs4730775 were significantly associated with HCC compared with N-HCC patients. The polymorphism rs4135385 of CTNNB1 genotype GA was associated with a higher risk for Stage III + IV HCC (modified Union for International Cancer Control) (P = 0.001, OR = 2.238).Genetic polymorphisms in the WNT2 and CTNNB1 genes were closely associated with HCC risk and progression in a Chinese Han population.

The role of alkaline phosphatase in intracellular lipid accumulation in the human hepatocarcinoma cell line, HepG2

Inhibition of tissue non-specific alkaline phosphatase (TNALP) decreases intracellular lipid accumulation in human preadipocytes and the murine preadipocyte cell line, 3T3-L1. Therefore, the current study was performed to determine if TNALP is required for intracellular lipid deposition in the human hepatocyte cell line, HepG2. Intracellular lipid accumulation, TNALP activity and peroxisome proliferator activated receptor (PPAR) γ gene expression were measured in HepG2 and 3T3-L1 cells in the presence and absence of the TNALP inhibitors levamisole and histidine. Sub-cellular TNALP activity was localized using cytochemical analysis. Both PPARγ gene expression and TNALP activity increased during intracellular lipid accumulation in HepG2 and 3T3-L1 cells. Inhibition of TNALP blocked intracellular lipid accumulation but did not alter expression of the PPARγ gene. In HepG2 cells, TNALP co-localized with adipophilin on the lipid droplet membrane. These data suggest a role for TNALP in lipid droplet formation, possibly downstream from PPARγ, within HepG2 and 3T3-L1 cells.

Tumor Microenvironment, a Paradigm in Hepatocellular Carcinoma Progression and Therapy

Hepatocellular carcinoma (HCC) is among the most lethal and prevalent cancers in the human population. Different etiological factors such as hepatitis B and C virus, alcohol and diabetes cause liver injury followed by inflammation, necrosis and hepatocytes proliferation. Continuous cycles of this destructive-regenerative process culminates in liver cirrhosis which is characterized by regenerating nodules that progress to dysplastic nodules and ultimately HCC. Despite its significance, there is only an elemental understanding of the pathogenetic mechanisms, and there are only limited therapeutic options. Therefore, the study of the involved molecular mechanisms can open a new insight to define more effective treatment strategies. A variety of alterations have been reported in HCC patients, particularly the cancer-associated microenvironment components including immune cells, fibroblast cells, endothelial cells and extracellular matrix can support the neoplastic cells to proliferate, growth and invade. This review summarizes the current state of knowledge and highlights the principal challenges that are relevant to controlling this milieu.

Tumor Microenvironment, a Paradigm in Hepatocellular Carcinoma Progression and Therapy

Hepatocellular carcinoma (HCC) is among the most lethal and prevalent cancers in the human population. Different etiological factors such as hepatitis B and C virus, alcohol and diabetes cause liver injury followed by inflammation, necrosis and hepatocytes proliferation. Continuous cycles of this destructive–regenerative process culminates in liver cirrhosis which is characterized by regenerating nodules that progress to dysplastic nodules and ultimately HCC. Despite its significance, there is only an elemental understanding of the pathogenetic mechanisms, and there are only limited therapeutic options. Therefore, the study of the involved molecular mechanisms can open a new insight to define more effective treatment strategies. A variety of alterations have been reported in HCC patients, particularly the cancer-associated microenvironment components including immune cells, fibroblast cells, endothelial cells and extracellular matrix can support the neoplastic cells to proliferate, growth and invade. This review summarizes the current state of knowledge and highlights the principal challenges that are relevant to controlling this milieu.

Healing efficacy of fracture-targeted GSK3β inhibitor-loaded micelles for improved fracture repair

Aim: To evaluate the fracture healing capabilities of a GSK3β inhibitor, 6-bromoindirubin-3′-oxime, coupled with an aspartic acid octapeptide in a micellar delivery system. Materials & methods: The efficacy of the intravenously administered micelles to accelerate healing of femoral fracture in mice was evaluated. Micro-computed tomography analysis was employed to obtain bone density, total volume, relative volume, trabecular thickness and trabecular spacing.Results: Both fracture bone mineral density and volume were significantly higher in the micelle treatment groups when compared with controls. The fracture-targeted micelle demonstrates fracture-specific bone anabolism and biocompatibility in off-target tissues. Conclusion: Accelerated fracture healing in mice was achieved by targeting the GSK3β inhibitor, 6-bromoindirubin-3′-oxime, to the fracture site.

Cisplatin-induced regulation of signal transduction pathways and transcription factors in p53-mutated subclone variants of hepatoma cells: Potential application for therapeutic targeting

Cisplatin is commonly recognized as a DNA-damaging drug; however, its versatile antitumor effects have been demonstrated to extend beyond this narrow functional attribute. The present study determined how cisplatin regulates alternative pathways and transcription factors to exert its additional antitumor actions. Cisplatin was observed to be able to trigger an endoplasmic reticulum stress response through aggravated nitrosative stress coupled to perturbed mitochondrial calcium (Ca²⁺) homeostasis, which substantially downregulated glucose-regulated protein (GRP) 78 expression by suppressing the cleavage of activating transcription factor (ATF) 6α (90 kDa) to its active 50 kDa subunit. Concomitantly, the ATF4-ATF3-C/emopamil binding protein homologous protein axis was activated by cisplatin, which triggered cellular glutathione (GSH) depletion by strongly inhibiting γ-glutamylcysteine synthetase heavy chain (γ-GCS_h), a key enzyme in GSH biosynthesis. The present study also demonstrated that cisplatin substantially inhibited β-catenin, causing a marked downregulation of survivin and B-cell lymphoma (Bcl)-2. Taken together, the present results uncovered a novel mechanism of cisplatin that could simultaneously trigger the inhibition of three prominent antiapoptotic effector molecules (Bcl-2, survivin and GRP78) and effectively promote GSH depletion by inhibiting γ-GCS_h. These newly discovered functional attributes of cisplatin can provide an avenue for novel combined therapeutic strategies to kill hepatocellular carcinoma cells effectively.

Isocoreopsin: An active constituent of n-butanol extract of Butea monosperma flowers against colorectal cancer (CRC)

The herb Butea monosperma constitutes several human health beneficial components, which are mostly studied for their anticancer effects. In this study, the activity of n-butanol fractions of B. monosperma floral extract was examined on inhibiting aberrant crypt foci (ACF) formation in azoxymethane induced Wistar albino rats. The n-butanol extracts (150 mg/kg) decreased the ACF formation (per rat) by 92% and 78% in short- and long-term in vivo treatments, respectively. All the compounds in the n-butanol extract were isolated and purified using column and reverse-phase high pressure liquid chromatography (HPLC). Their structures were characterized using UV-visible spectroscopy, nuclear magnetic resonance (NMR) and electrospray-ionisation mass spectrometry (ESI-MS) to determine important flavonoids, namely isocoreopsin, butrin and isobutrin. These compounds were studied for their free radical scavenging and anticancer activities. The compound isocoreopsin showed significantly greater efficacy in cell death on human colon and liver cancer cell lines (50 μg/mL in HT-29 and 100 μg/mL in HepG2) than butrin (100 μg/mL in HT-29 and 500 μg/mL in HepG2) and isobutrin (80 μg/mL in HT-29 and 150 μg/mL in HepG2). These results suggest that isocoreopsin, butrin and isobutrin are the important key compounds for the chemoprevention of colon cancer and isocoreopsin can be considered as a promising novel drug.

Aberrant regulation of Wnt signaling in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies in the world. Several signaling pathways, including the wingless/int-1 (Wnt) signaling pathway, have been shown to be commonly activated in HCC. The Wnt signaling pathway can be triggered via both catenin β1 (CTNNB1)-dependent (also known as “canonical”) and CTNNB1-independent (often referred to as “non-canonical”) pathways. Specifically, the canonical Wnt pathway is one of those most frequently reported in HCC. Aberrant regulation from three complexes (the cell-surface receptor complex, the cytoplasmic destruction complex and the nuclear CTNNB1/T-cell-specific transcription factor/lymphoid enhancer binding factor transcriptional complex) are all involved in HCC. Although the non-canonical Wnt pathway is rarely reported, two main non-canonical pathways, Wnt/planar cell polarity pathway and Wnt/Ca²⁺ pathway, participate in the regulation of hepatocarcinogenesis. Interestingly, the canonical Wnt pathway is antagonized by non-canonical Wnt signaling in HCC. Moreover, other signaling cascades have also been demonstrated to regulate the Wnt pathway through crosstalk in HCC pathogenesis. This review provides a perspective on the emerging evidence that the aberrant regulation of Wnt signaling is a critical mechanism for the development of HCC. Furthermore, crosstalk between different signaling pathways might be conducive to the development of novel molecular targets of HCC.