Somatic mutations of the beta-catenin gene are frequent in mouse and human hepatocellular carcinomas

How tumors escape the immune system

Mutations in the gene for β-catenin cause liver cancer cells to release fewer exosomes, which reduces the number of immune cells infiltrating the tumor.

DLK1/DIO3 locus upregulation by a β-catenin-dependent enhancer drives cell proliferation and liver tumorigenesis

The CTNNB1 gene, encoding β-catenin, is frequently mutated in hepatocellular carcinoma (HCC, ∼30%) and in hepatoblastoma (HB, >80%), in which DLK1/DIO3 locus induction is correlated with CTNNB1 mutations. Here, we aim to decipher how sustained β-catenin activation regulates DLK1/DIO3 locus expression and the role this locus plays in HB and HCC development in mouse models deleted for Apc (ApcΔhep) or Ctnnb1-exon 3 (β-cateninΔExon3) and in human CTNNB1-mutated hepatic cancer cells. We identified an enhancer site bound by TCF-4/β-catenin complexes in an open conformation upon sustained β-catenin activation (DLK1-Wnt responsive element [WRE]) and increasing DLK1/DIO3 locus transcription in β-catenin-mutated human HB and mouse models. DLK1-WRE editing by CRISPR-Cas9 approach impaired DLK1/DIO3 locus expression and slowed tumor growth in subcutaneous CTNNB1-mutated tumor cell grafts, ApcΔhep HB and β-cateninΔExon3 HCC. Tumor growth inhibition resulted either from increased FADD expression and subsequent caspase-3 cleavage in the first case or from decreased expression of cell cycle actors regulated by FoxM1 in the others. Therefore, the DLK1/DIO3 locus is an essential determinant of FoxM1-dependent cell proliferation during β-catenin-driven liver tumorigenesis. Targeting the DLK1-WRE enhancer to silence the DLK1/DIO3 locus might thus represent an interesting therapeutic strategy to restrict tumor growth in primary liver cancers with CTNNB1 mutations.

Genomic analysis of an aggressive hepatic leiomyosarcoma case following treatment for hepatocellular carcinoma

A 70-year-old man undergoing treatment for immunoglobulin G4-related disease developed a liver mass on computed tomography during routine imaging examination. The tumor was located in the hepatic S1/4 region, was 38 mm in size, and showed arterial enhancement on dynamic contrast-enhanced computed tomography. We performed a liver biopsy and diagnosed moderately differentiated hepatocellular carcinoma. The patient underwent proton beam therapy. The tumor remained unchanged but enlarged after 4 years. The patient was diagnosed with hepatocellular carcinoma recurrence and received hepatic arterial chemoembolization. However, 1 year later, the patient developed jaundice, and the liver tumor grew in size. Unfortunately, the patient passed away. Autopsy revealed that the tumor consisted of spindle-shaped cells exhibiting nuclear atypia and a fission pattern and tested positive for α-smooth muscle actin and vimentin. No hepatocellular carcinoma components were observed, and the patient was pathologically diagnosed with hepatic leiomyosarcoma. Next-generation sequencing revealed somatic mutations in CACNA2D4, CTNNB1, DOCK5, IPO8, MTMR1, PABPC5, SEMA6D, and ZFP36L1. Based on the genetic mutation, sarcomatoid hepatocarcinoma was the most likely pathogenesis in this case. This mutation is indicative of the transition from sarcomatoid hepatocarcinoma to hepatic leiomyosarcoma.

WNT/β-catenin signaling in hepatocellular carcinoma: The aberrant activation, pathogenic roles, and therapeutic opportunities

Hepatocellular carcinoma (HCC) is a liver cancer, highly heterogeneous both at the histopathological and molecular levels. It arises from hepatocytes as the result of the accumulation of numerous genomic alterations in various signaling pathways, including canonical WNT/β-catenin, AKT/mTOR, MAPK pathways as well as signaling associated with telomere maintenance, p53/cell cycle regulation, epigenetic modifiers, and oxidative stress. The role of WNT/β-catenin signaling in liver homeostasis and regeneration is well established, whereas in development and progression of HCC is extensively studied. Herein, we review recent advances in our understanding of how WNT/β-catenin signaling facilitates the HCC development, acquisition of stemness features, metastasis, and resistance to treatment. We outline genetic and epigenetic alterations that lead to activated WNT/β-catenin signaling in HCC. We discuss the pivotal roles of CTNNB1 mutations, aberrantly expressed non-coding RNAs and complexity of crosstalk between WNT/β-catenin signaling and other signaling pathways as challenging or advantageous aspects of therapy development and molecular stratification of HCC patients for treatment.

Detection of driver mutations and genomic signatures in endometrial cancers using artificial intelligence algorithms

Analyzed endometrial cancer (EC) genomes have allowed for the identification of molecular signatures, which enable the classification, and sometimes prognostication, of these cancers. Artificial intelligence algorithms have facilitated the partitioning of mutations into driver and passenger based on a variety of parameters, including gene function and frequency of mutation. Here, we undertook an evaluation of EC cancer genomes deposited on the Catalogue of Somatic Mutations in Cancers (COSMIC), with the goal to classify all mutations as either driver or passenger. Our analysis showed that approximately 2.5% of all mutations are driver and cause cellular transformation and immortalization. We also characterized nucleotide level mutation signatures, gross chromosomal re-arrangements, and gene expression profiles. We observed that endometrial cancers show distinct nucleotide substitution and chromosomal re-arrangement signatures compared to other cancers. We also identified high expression levels of the CLDN18 claudin gene, which is involved in growth, survival, metastasis and proliferation. We then used in silico protein structure analysis to examine the effect of certain previously uncharacterized driver mutations on protein structure. We found that certain mutations in CTNNB1 and TP53 increase protein stability, which may contribute to cellular transformation. While our analysis retrieved previously classified mutations and genomic alterations, which is to be expected, this study also identified new signatures. Additionally, we show that artificial intelligence algorithms can be effectively leveraged to accurately predict key drivers of cancer. This analysis will expand our understanding of ECs and improve the molecular toolbox for classification, diagnosis, or potential treatment of these cancers.

Quantitative ctDNA Detection in Hepatoblastoma: Implications for Precision Medicine

Hepatoblastoma is characterized by driver mutations in CTNNB1, making it an attractive biomarker for a liquid biopsy approach utilizing circulating tumor DNA (ctDNA). This prospective observational study sought to ascertain the feasibility of ctDNA detection in patients with hepatoblastoma and explore its associations with established clinical indicators and biomarkers, including serum Alpha-fetoprotein (AFP). We obtained 38 plasma samples and 17 tumor samples from 20 patients with hepatoblastoma. These samples were collected at various stages: 10 at initial diagnosis, 17 during neoadjuvant chemotherapy, 6 post-operatively, and 5 at disease recurrence. Utilizing a bespoke sequencing assay we developed called QUENCH, we identified single nucleotide variants and deletions in CTNNB1 ctDNA. Our study demonstrated the capability to quantitate ctDNA down to a variant allele frequency of 0.3%, achieving a sensitivity of 90% for patients at initial diagnosis, and a specificity of 100% at the patient level. Notably, ctDNA positivity correlated with tumor burden, and ctDNA levels exhibited associations with macroscopic residual disease and treatment response. Our findings provide evidence for the utility of quantitative ctDNA detection in hepatoblastoma management. Given the distinct detection targets, ctDNA and AFP-based stratification and monitoring approaches could synergize to enhance clinical decision-making. Further research is needed to elucidate the interplay between ctDNA and AFP and determine the optimal clinical applications for both methods in risk stratification and residual disease detection.

Infantile Sinonasal Myxoma Is Clinically and Genetically Distinct From Other Myxomas of the Craniofacial Bones and From Desmoid Fibromatosis

Sinonasal myxomas are rare benign tumors of the maxillary bone and sinus. There is published evidence that sinonasal myxomas occurring in children up to 3 years of age ("infantile sinonasal myxomas") are clinically distinctive and harbor Wnt signaling pathway alterations. Here, we characterized 16 infantile sinonasal myxomas and compared them to 19 maxillary myxomas and 11 mandibular myxomas in older patients. Clinical follow-up was available for 21 patients (46%) overall (median: 2.6 y; range: 4 mo to 21 y), including 10 of 16 infantile sinonasal myxomas (62%). None of the 8 resected infantile sinonasal myxomas recurred, despite positive margins in 6 of them. One incompletely resected infantile sinonasal myxoma underwent partial regression without additional treatment. In contrast, 4 of the 11 other myxomas with follow-up recurred (36%), including one that recurred twice. Imaging studies demonstrated all infantile sinonasal myxomas to be expansile lesions arising from the anterior maxillary bone adjacent to the nasal aperture, with peripheral reactive bone formation. Histologically, infantile sinonasal myxomas showed short, intersecting fascicles of bland fibroblastic cells with prominent stromal vessels. Examples with collagenous stroma showed some morphologic overlap with desmoid fibromatosis, although none showed infiltrative growth into adjacent soft tissue. Immunohistochemistry demonstrated nuclear β-catenin expression in 14 of 15 infantile sinonasal myxomas (93%), in contrast to 4 of 26 other myxomas of craniofacial bones (15%). Smooth muscle actin was expressed in only 1 of 11 infantile sinonasal myxomas (9%). Next-generation sequencing was successfully performed on 10 infantile sinonasal myxomas and 7 other myxomas. Infantile sinonasal myxomas harbored CTNNB1 point mutations in 4 cases (D32Y, G34E, G34R, and I35S), and none harbored alterations to the phosphorylation sites T41 and S45 that are altered in 99% of CTNNB1 -mutant desmoid fibromatoses. Three tumors showed alterations consistent with biallelic APC inactivation. Three infantile sinonasal myxomas that showed strong nuclear β-catenin expression were negative for CTNNB1 and APC alterations. Sequencing was negative for CTNNB1 or APC alterations in all 7 myxomas of craniofacial bones in older patients. Four of these myxomas in older patients (57%) showed copy number alterations, and all lacked known driving alterations. These findings support the notion that infantile sinonasal myxomas are clinically and genetically distinctive, and we propose the use of the diagnostic term "infantile sinonasal myxoma" to distinguish this tumor type from other myxomas of the craniofacial bones. Infantile sinonasal myxoma should be distinguished from desmoid fibromatosis because of its unique clinical presentation, more indolent clinical behavior, different morphology, different immunohistochemical profile, and different genetics. Given its indolent behavior even when marginally excised, infantile sinonasal myxoma can be managed with conservative surgery.

Diet-induced rewiring of the Wnt gene regulatory network connects aberrant splicing to fatty liver and liver cancer in DIAMOND mice

Several preclinical models have been recently developed for metabolic associated fatty liver disease (MAFLD) and associated hepatocellular carcinoma (HCC) but comprehensive analysis of the regulatory and transcriptional landscapes underlying disease in these models are still missing. We investigated the regulatory and transcriptional landscape in fatty livers and liver tumours from DIAMOND mice that faithfully mimic human HCC development in the context of MAFLD. RNA-sequencing and ChIP-sequencing revealed rewiring of the Wnt/β-catenin regulatory network in DIAMOND tumours, as manifested by chromatin remodelling and associated switching in the expression of the canonical TCF/LEF downstream effectors. We identified splicing as a major mechanism leading to constitutive oncogenic activation of β-catenin in a large subset of DIAMOND tumours, a mechanism that is independent on somatic mutations in the locus and that has not been previously shown. Similar splicing events were found in a fraction of human HCC and hepatoblastoma samples.

A combined bioinformatics and experimental approach identifies RMI2 as a Wnt/β-catenin signaling target gene related to hepatocellular carcinoma

BACKGROUND

The Wnt/β-catenin signaling pathway plays an important role in embryogenesis and tumorigenesis. In human cancer, abnormal activity of Wnt/β-catenin signaling pathway induces overexpressed of downstream genes, and initiate oncogene. There are several target genes known to be key players in tumorigenesis, such as c-myc, cyclin D1, MMPs or survivin. Therefore, identifying the target genes of Wnt/β-catenin signaling pathway is important to understanding Wnt/β-catenin-mediated carcinogenesis. In this study, we developed a combined bioinformatics and experimental approach to find potential target genes.

METHODS

Luciferase reporter assay was used to analyze the promoter activity of RMI2. WST1 cell proliferation assays and transwell assays were performed to determine the proliferation and migration capacities of RMI2 overexpressing or knockdown stable hepatic cells. Finally, xenograft experiments were performed to measure the tumor formation capacity in vivo.

RESULTS

The results showed that RMI2 mRNA was upregulated after LiCl treatment and Wnt3a-conditioned medium in a culture of SK-hep-1 cell lines. A chromatin immunoprecipitation (ChIP) assay showed that the β-catenin/T cell-specific factor (TCF) complex binds to the putative TCF binding site of the RMI2 promoter. We then found a TCF binding site at - 333/- 326 of the RMI2 promoter, which is crucial for β-catenin responsiveness in liver cell lines. RMI2 was overexpressed in hepatoma tissue and cell lines, and it promoted the migration and invasion of HCC cells. Moreover, RMI2 upregulated the expression of epithelial-mesenchymal transition (EMT) markers and the Wnt3a/β-catenin-related genes, but silencing RMI2 had the opposite effects. Notably, the expression of RMI2 was positively correlated with the clinical data of HCC patients who had significantly shorter overall survival (OS) and disease-free survival (DFS) (Both: P < 0.05). In addition, a total of 373 HCC patients' data from the Caner Genome Atlas project (TCGA) were used to validate our findings.

CONCLUSIONS

Taking all these findings together, we determined that RMI2 was a new target gene of the Wnt/β-catenin signaling pathway. We also found that RMI2 promotes EMT markers, HCC cell invasion, and metastasis, which indicated that RMI2 is a potential target for preventing or at least mitigating the progression of HCC.

WNT enhancing signals in pancreatic cancer are transmitted by LGR6

The G-protein-coupled receptor LGR6 associates with ligands of the R-Spondin (RSPO) family to potentiate preexisting signals of the canonical WNT pathway. However, its importance in pancreatic ductal adenocarcinoma (PDAC) remains unclear. Here, we show that LGR6 is differentially expressed in various PDAC cell lines of mesenchymal and epithelial phenotype, respectively, siding with the latter subsets. LGR6 expression is altered based upon the cells' WNT activation status. Furthermore, extrinsic enhancement of WNT pathway signaling increased LGR6 expression suggestive of a reinforcing self-regulatory loop in highly WNT susceptible cells. Downregulation of LGR6 on the other hand, seemed to tamper those effects. Last, downregulation of LGR6 reduced cancer stemness as determined by functional in vitro assays. These findings shed new insights into regulatory mechanisms for the canonical WNT pathway in pancreatic cancer cells. It may also have potential value for treatment stratification of PDAC.

Current progress of pig models for liver cancer research

Preclinical trials play critical roles in assessing the safety and efficiency of novel therapeutic strategies for human diseases including live cancer. However, most therapeutic strategies that were proved to be effective in preclinical cancer models failed in human clinical trials due to the lack of appropriate disease animal models. Therefore, it is of importance and urgent to develop a precise animal model for preclinical cancer research. Liver cancer is one of the most frequently diagnosed cancers with low 5-year survival rate. Recently, porcine attracted increasing attentions as animal model in biomedical research. Porcine liver cancer model may provide a promising platform for biomedical research due to their similarities to human being in body size, anatomical characteristics, physiology and pathophysiology. In this review, we comprehensively summarized and discussed the advantages and disadvantages, rationale, current status and progress of pig models for liver cancer research.

Zebrafish imaging reveals hidden oncogenic-normal cell communication during primary tumorigenesis

Oncogenic mutations drive tumorigenesis, and single cells with oncogenic mutations act as the tumor seeds that gradually evolve into fully transformed tumors. However, oncogenic cell behavior and communication with neighboring cells during primary tumorigenesis remain poorly understood. We used the zebrafish, a small vertebrate model suitable for in vivo cell biology, to address these issues. We describe the cooperative and competitive communication between oncogenic cells and neighboring cells, as revealed by our recent zebrafish imaging studies. Newly generated oncogenic cells are actively eliminated by neighboring cells in healthy epithelia, whereas oncogenic cells cooperate with their neighbors to prime tumorigenesis in unhealthy epithelia via additional mutations or inflammation. In addition, we discuss the potential of zebrafish in vivo imaging to determine the initial steps of human tumorigenesis.Key words: zebrafish, imaging, cell-cell communication, cell competition, EDAC, senescence, primary tumorigenesis.

Antagonism between wild-type and mutant β-catenin controls hepatoblastoma differentiation via fascin-1

Background & Aims

β-catenin is a well-known effector of the Wnt pathway, and a key player in cadherin-mediated cell adhesion. Oncogenic mutations of β-catenin are very frequent in paediatric liver primary tumours. Those mutations are mostly heterozygous, which allows the co-expression of wild-type (WT) and mutated β-catenins in tumour cells. We investigated the interplay between WT and mutated β-catenins in liver tumour cells, and searched for new actors of the β-catenin pathway.

Methods

Using an RNAi strategy in β-catenin-mutated hepatoblastoma (HB) cells, we dissociated the structural and transcriptional activities of β-catenin, which are carried mainly by WT and mutated proteins, respectively. Their impact was characterised using transcriptomic and functional analyses. We studied mice that develop liver tumours upon activation of β-catenin in hepatocytes (APC^KO and β-catenin^Δexon3 mice). We used transcriptomic data from mouse and human HB specimens, and used immunohistochemistry to analyse samples.

Results

We highlighted an antagonistic role of WT and mutated β-catenins with regard to hepatocyte differentiation, as attested by alterations in the expression of hepatocyte markers and the formation of bile canaliculi. We characterised fascin-1 as a transcriptional target of mutated β-catenin involved in tumour cell differentiation. Using mouse models, we found that fascin-1 is highly expressed in undifferentiated tumours. Finally, we found that fascin-1 is a specific marker of primitive cells including embryonal and blastemal cells in human HBs.

Conclusions

Fascin-1 expression is linked to a loss of differentiation and polarity of hepatocytes. We present fascin-1 as a previously unrecognised factor in the modulation of hepatocyte differentiation associated with β-catenin pathway alteration in the liver, and as a new potential target in HB.

Impact and implications

The FSCN1 gene, encoding fascin-1, was reported to be a metastasis-related gene in various cancers. Herein, we uncover its expression in poor-prognosis hepatoblastomas, a paediatric liver cancer. We show that fascin-1 expression is driven by the mutated beta-catenin in liver tumour cells. We provide new insights on the impact of fascin-1 expression on tumour cell differentiation. We highlight fascin-1 as a marker of immature cells in mouse and human hepatoblastomas.

CRISPR-induced exon skipping of β-catenin reveals tumorigenic mutants driving distinct subtypes of liver cancer

CRISPR/Cas9-driven cancer modeling studies are based on the disruption of tumor suppressor genes by small insertions or deletions (indels) that lead to frame-shift mutations. In addition, CRISPR/Cas9 is widely used to define the significance of cancer oncogenes and genetic dependencies in loss-of-function studies. However, how CRISPR/Cas9 influences gain-of-function oncogenic mutations is elusive. Here, we demonstrate that single guide RNA targeting exon 3 of Ctnnb1 (encoding β-catenin) results in exon skipping and generates gain-of-function isoforms in vivo. CRISPR/Cas9-mediated exon skipping of Ctnnb1 induces liver tumor formation in synergy with YAPS127A in mice. We define two distinct exon skipping-induced tumor subtypes with different histological and transcriptional features. Notably, ectopic expression of two exon-skipped β-catenin transcript isoforms together with YAPS127A phenocopies the two distinct subtypes of liver cancer. Moreover, we identify similar CTNNB1 exon-skipping events in patients with hepatocellular carcinoma. Collectively, our findings advance our understanding of β-catenin-related tumorigenesis and reveal that CRISPR/Cas9 can be repurposed, in vivo, to study gain-of-function mutations of oncogenes in cancer. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Design, synthesis and biological evaluation of quercetin derivatives as novel β-catenin/B-cell lymphoma 9 protein-protein interaction inhibitors

The β-catenin/B-cell lymphoma 9 (BCL9) protein-protein interaction (PPI) is a potential target for the suppression of hyperactive Wnt/β-catenin signaling that is vigorously involved in cancer initiation and development. Herein, we first described quercetin and its derivatives had potential inhibitory effects on β-catenin/BCL9 PPI. The most potent compound, quercetin-3'-O-(4-methylpiperazine-1-yl) propyl (C1), directly binded with β-catenin and disrupted the β-catenin/BCL9 interaction in both the protein level and the cellular context. C1 also effectively inhibited colorectal cancer in vitro and showed better selectivity in inhibiting hyperactive Wnt/β-catenin signaling cells like CT26 and HCT116. And we further confirmed that C1 could inhibit CT26 tumor growth in vivo and regulate the tumor immune microenvironment. This study provides a good chemical probe to explore β-catenin-related biology and a drug-like quercetin derivative as novel β-catenin/BCL9 PPI inhibitors for further drug development.

Human VH-based chimeric antigen receptor T cells targeting glypican 3 eliminate tumors in preclinical models of HCC

BACKGROUND AND AIMS

Efficacy of chimeric antigen receptor (CAR) T cells for treating solid tumors, including HCC, remains a challenge. Nanobodies are emerging building blocks of CAR T cells due to their small size and high expression. Membrane proximal sites have been shown as attractive epitopes of CAR T cells. However, current CAR formats are not tailored toward nanobodies or targeting membrane distal epitopes.

APPROACH AND RESULTS

Using hYP7 Fv (membrane proximal) and HN3 VH nanobody (membrane distal) as GPC3 targeting elements, we sought to determine how hinges and transmembrane portions of varying structures and sizes affect CAR T-cell function. We generated multiple permutations of CAR T cells containing CD8, CD28, IgG4, and Fc domains. We show that engineered HN3 CAR T cells can be improved by 2 independent, synergistic changes in the hinge and transmembrane domains. The T cells expressing the HN3 CAR which contains the hinge region of IgG4 and the CD28 transmembrane domain (HN3-IgG4H-CD28TM) exhibited high cytotoxic activity and caused complete HCC tumor eradication in immunodeficient mice. HN3-IgG4H-CD28TM CAR T cells were enriched for cytotoxic-memory CD8+ T cells and NFAT signals, and reduced β catenin levels in HCC cells.

CONCLUSION

Our findings indicate that altering the hinge and transmembrane domains of a nanobody-based CAR targeting a distal GPC3 epitope, in contrast to a membrane proximal epitope, lead to robust T-cell signaling and induce swift and durable eradication of HCC tumors.

Inhibition of Heat Shock Factor 1 Signaling Decreases Hepatoblastoma Growth via Induction of Apoptosis

Although rare compared with adult liver cancers, hepatoblastoma (HB) is the most common pediatric liver malignancy, and its incidence is increasing. Currently, the treatment includes surgical resection with or without chemotherapy, and in severe cases, liver transplantation in children. The effort to develop more targeted, HB-specific therapies has been stymied by the lack of fundamental knowledge about HB biology. Heat shock factor 1 (HSF1), a transcription factor, is a canonical inducer of heat shock proteins, which act as chaperone proteins to prevent or undo protein misfolding. Recent work has shown a role for HSF1 in cancer beyond the canonical heat shock response. The current study found increased HSF1 signaling in HB versus normal liver. It showed that less differentiated, more embryonic tumors had higher levels of HSF1 than more differentiated, more fetal-appearing tumors. Most strikingly, HSF1 expression levels correlated with mortality. This study used a mouse model of HB to test the effect of inhibiting HSF1 early in tumor development on cancer growth. HSF1 inhibition resulted in fewer and smaller tumors, suggesting HSF1 is needed for aggressive tumor growth. Moreover, HSF1 inhibition also increased apoptosis in tumor foci. These data suggest that HSF1 may be a viable pharmacologic target for HB treatment.

Hepatocellular carcinoma and solid pseudopapillary neoplasm of the pancreas complicating familial adenomatous polyposis: two cases and review of the literature

Familial adenomatous polyposis (FAP) is characterized by colorectal polyposis and extracolonic tumors. Adenocarcinoma of the pancreas and hepatocellular carcinoma are rare in FAP. In this case series, we describe a mother and daughter with FAP who developed a hepatocellular carcinoma and solid pseudopapillary neoplasm of the pancreas, respectively.

Alterations of Cytoskeleton Networks in Cell Fate Determination and Cancer Development

Cytoskeleton proteins have been long recognized as structural proteins that provide the necessary mechanical architecture for cell development and tissue homeostasis. With the completion of the cancer genome project, scientists were surprised to learn that huge numbers of mutated genes are annotated as cytoskeletal or associated proteins. Although most of these mutations are considered as passenger mutations during cancer development and evolution, some genes show high mutation rates that can even determine clinical outcomes. In addition, (phospho)proteomics study confirms that many cytoskeleton-associated proteins, e.g., β-catenin, PIK3CA, and MB21D2, are important signaling mediators, further suggesting their biofunctional roles in cancer development. With emerging evidence to indicate the involvement of mechanotransduction in stemness formation and cell differentiation, mutations in these key cytoskeleton components may change the physical/mechanical properties of the cells and determine the cell fate during cancer development. In particular, tumor microenvironment remodeling triggered by such alterations has been known to play important roles in autophagy, metabolism, cancer dormancy, and immune evasion. In this review paper, we will highlight the current understanding of how aberrant cytoskeleton networks affect cancer behaviors and cellular functions through mechanotransduction.

Epigenetic silencing of JAM3 promotes esophageal cancer development by activating Wnt signaling

BACKGROUND

The role of JAM3 in different tumors is controversial. The epigenetic regulation and the mechanism of JAM3 remain to be elucidated in human esophageal cancer (EC).

METHODS

Eleven EC cell lines, 49 cases of esophageal intraepithelial neoplasia (EIN) and 760 cases of primary EC samples were employed. Methylation-specific polymerase chain reaction, immunohistochemistry, MTT, western blot and xenograft mouse models were applied in this study.

RESULTS

The inverse association between RNA expression and promoter region methylation of JAM3 was found by analyzing 185 cases of EC samples extracted from the TCGA database (p < 0.05). JAM3 was highly expressed in KYSE450, KYSE520, TE1 and YES2 cells, low level expressed in KYSE70 cells and unexpressed in KYSE30, KYSE150, KYSE410, KYSE510, TE13 and BIC1 cells. JAM3 was unmethylated in KYSE450, KYSE520, TE1 and YES2 cells, partial methylated in KYSE70 cells and completely methylated in KYSE30, KYSE150, KYSE410, KYSE510, TE13 and BIC1 cells. The expression of JAM3 is correlated with methylation status. The levels of JAM3 were unchanged in KYSE450, KYSE520, TE1 and YES2 cells, increased in KYSE70 cells and restored expression in KYSE30, KYSE150, KYSE410, KYSE510, TE13 and BIC1 cells after 5-aza-2'-deoxycytidine treatment, suggesting that the expression of JAM3 is regulated by promoter region methylation. JAM3 was methylated in 26.5% (13/49) of EIN and 51.1% (388/760) of primary EC, and methylation of JAM3 was associated significantly with tumor differentiation and family history (all p < 0.05). Methylation of JAM3 is an independent prognostic factor of poor 5-year overall survival (p < 0.05). JAM3 suppresses cell proliferation, colony formation, migration and invasion and induces G1/S arrest and apoptosis in EC. Further study demonstrated that JAM3 suppressed EC cells and xenograft tumor growth by inhibiting Wnt/β-catenin signaling.

CONCLUSION

JAM3 is frequently methylated in human EC, and the expression of JAM3 is regulated by promoter region methylation. JAM3 methylation is an early detection and prognostic marker of EC. JAM3 suppresses EC growth both in vitro and in vivo by inhibiting Wnt signaling.

SOX9 and TCF transcription factors associate to mediate Wnt/β-catenin target gene activation in colorectal cancer

Activation of the Wnt/β-catenin pathway regulates gene expression by promoting the formation of a β-catenin-T-cell factor (TCF) complex on target enhancers. In addition to TCFs, other transcription factors interact with the Wnt/β-catenin pathway at different levels to produce tissue-specific patterns of Wnt target gene expression. The transcription factor SOX9 potently represses many Wnt target genes by downregulating β-catenin protein levels. Here, we find using colony formation and cell growth assays that SOX9 surprisingly promotes the proliferation of Wnt-driven colorectal cancer (CRC) cells. In contrast to how it indirectly represses Wnt targets, SOX9 directly co-occupies and activates multiple Wnt-responsive enhancers in CRC cells. Our examination of the binding site grammar of these enhancers shows the presence of TCF and SOX9 binding sites that are necessary for transcriptional activation. In addition, we identify a physical interaction between the DNA-binding domains of TCFs and SOX9 and show that TCF-SOX9 interactions are important for target gene regulation and CRC cell growth. Our work demonstrates a highly context-dependent effect of SOX9 on Wnt targets, with the presence or absence of SOX9-binding sites on Wnt-regulated enhancers determining whether they are directly activated or indirectly repressed by SOX9.

Promotion effect on liver tumor progression of microcystin-LR at environmentally relevant levels in female krasV12 transgenic zebrafish

Microcystin-LR (MC-LR) is a kind of natural toxin which exists widely in aquatic environments and has been reported to be hepatotoxic and carcinogenic. At present, the promoting mechanism of MC-LR on hepatocellular carcinoma (HCC) remains largely unexplored. In this study, the hepatocellular promoting effect of MC-LR was described in Kras^V12 transgenic zebrafish, a doxycycline (DOX) inducible HCC model. Our results showed that MC-LR could aggravate the progression of HCC at an environmentally relevant concentration (3 μg/L), which was accompanied by the decreased activity and down-regulated transcription level of serine/threonine phosphatase 2A (PP2A). Using TMT labeling quantitative phosphoproteomics, we found that the 1049 phosphopeptides were significantly changed (508 up-regulated and 541 down-regulated) in liver from combined exposure to DOX and 3 μg/L MC-LR group compared to the DOX group. Enriched pathways by KEGG analysis suggested that differentially phosphorylated proteins were mainly related to Wnt signaling pathway. Furthermore, the mRNA expression and protein abundance of β-Catenin in Wnt signaling pathway were significantly up-regulated following exposure to MC-LR. In short, our results suggested that MC-LR significantly inhibited the activity of PP2A, which in turn activated Wnt signaling, eventually resulting in progression of liver tumor in transgenic zebrafish.

Overview and clinical significance of multiple mutations in individual genes in hepatocellular carcinoma

Background

Multiple mutation (MM) within a single gene has recently been reported as a mechanism involved in carcinogenesis. The present study investigated the clinical significance of MMs in hepatocellular carcinoma (HCC).

Methods

Two hundred twenty-three surgically resected HCCs were subjected to gene expression profiling and whole-exome sequencing.

Results

MMs in individual genes were detected in 178 samples (MM tumors: 79.8%). The remaining samples all carried a single mutation (SM tumors: 20.2%). Recurrence-free survival in the MM group was significantly worse in comparison to the SM group (P = 0.012). A Cox proportional hazard analysis revealed that MM tumor was an independent predictor for worse a prognosis (hazard ratio, 1.72; 95% confidence interval, 1.01–3.17; P = 0.045). MMs were frequently observed across in various genes, especially MUC16 (15% of samples had at least one mutation in the gene) and CTNNB1 (14%). Although the MUC16 mRNA expression of MUC16 wild-type and MUC16 SM tumors did not differ to a statistically significant extent, the expression in MUC16 MM tumors was significantly enhanced in comparison to MUC16 SM tumors (P < 0.001). In MUC16, MMs were associated with viral hepatitis, higher tumor marker levels and vascular invasion. The MUC16 MMs group showed significantly worse recurrence-free survival in comparison to the MUC16 SM group (P = 0.022), while no significant difference was observed between the MUC16 SM group and the MUC16 wild-type group (P = 0.324).

Conclusions

MM was a relatively common event that may occur selectively in specific oncogenes and is involved in aggressive malignant behavior.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10143-z.

Targeting ligand-dependent wnt pathway dysregulation in gastrointestinal cancers through porcupine inhibition

Gastrointestinal cancers are responsible for more cancer deaths than any other system of the body. This review summarises how Wnt pathway dysregulation contributes to the development of the most common gastrointestinal cancers, with a particular focus on the nature and frequency of upstream pathway aberrations. Tumors with upstream aberrations maintain a dependency on the presence of functional Wnt ligand, and are predicted to be tractable to inhibitors of Porcupine, an enzyme that plays a key role in Wnt secretion. We summarise available pre-clinical efficacy data from Porcupine inhibitors in vitro and in vivo, as well as potential toxicities and the data from early phase clinical trials. We appraise the rationale for biomarker-defined targeted approaches, as well as outlining future opportunities for combination with other therapeutics.

Role of genetic testing in hepatic, pancreatic, and biliary cancers

Hepatic, pancreatic, and biliary (HPB) cancers, including hepatocellular carcinoma (HCC), pancreatic ductal adenocarcinoma (PDAC), and cholangiocarcinoma (CCA) cause a disproportionate amount of the global cancer-related mortality. Despite advances in surgical technique and improved systemic therapies, overall 5-year survival remains dismal, especially for patients with pancreatic and biliary cancer. Historically, systemic therapies for patients with HPB cancers were administered in a "one-size-fits-all" approach due to limited reliable data on efficacy for specific patient populations. However, recent advances in genetic testing techniques have greatly improved our understanding of HPB oncogenesis, shedding light on specific genetic mutations responsible for progression from physiologic cellular regulation to uninhibited cellular replication and invasive cancer. Investigations into the oncogenesis of HPB cancers have revealed multiple actionable genetic variants, as well as increased susceptibilities to currently available systemic therapies. For example, patients with PDAC and a known BRCA mutation are more likely to benefit from FOLFIRINOX or gemcitabine plus cisplatin. While patients with CCA and a IDH1 mutation may benefit from ivosidenib. As a result, many national and societal guidelines now recommend some form of genetic testing in the workup of patients with HPB cancers. We herein review the role of genetic testing in these aggressive cancers including DNA sequencing techniques, clinically relevant mutations, therapeutic implications, and current clinical recommendations.

Constitutive Occurrence of E:N-cadherin Heterodimers in Adherens Junctions of Hepatocytes and Derived Tumors

Cell–cell junctions are pivotal for embryogenesis and tissue homeostasis but also play a major role in tumorigenesis, tumor invasion, and metastasis. E-cadherin (CDH1) and N-cadherin (CDH2) are two adherens junction’s transmembrane glycoproteins with tissue-specific expression patterns in epithelial and neural/mesenchymal cells. Aberrant expression has been implicated in the process of epithelial–mesenchymal transition (EMT) in malignant tumors. We could hitherto demonstrate cis-E:N-cadherin heterodimer in endoderm-derived cells. Using immunoprecipitation in cultured cells of the line PLC as well as in human hepatocellular carcinoma (HCC)-lysates, we isolated E-N-cadherin heterodimers in a complex with the plaque proteins α- and β-catenin, plakoglobin, and vinculin. In confocal laser scanning microscopy, E-cadherin co-localized with N-cadherin at the basolateral membrane of normal hepatocytes, hepatocellular adenoma (HCA), and in most cases of HCC. In addition, we analyzed E- and N-cadherin expression via immunohistochemistry in a large cohort of 868 HCCs from 570 patients, 25 HCA, and respective non-neoplastic liver tissue, and correlated our results with multiple prognostic markers. While E- or N-cadherin were similarly expressed in tumor sites with vascular invasion or HCC metastases, HCC with vascular encapsulated tumor clusters (VETC) displayed slightly reduced E-cadherin, and slightly increased N-cadherin expression. Analyzing The Cancer Genome Atlas patient cohort, we found that reduced mRNA levels of CDH1, but not CDH2 were significantly associated with unfavorable prognosis; however, in multivariate analysis, CDH1 did not correlate with prognosis. In summary, E- and N-cadherin are specific markers for hepatocytes and derived HCA and HCC. E:N-cadherin heterodimers are constitutively expressed in the hepatocytic lineage and only slightly altered in malignant progression, thereby not complying with the concept of EMT.

Deleting the β-catenin degradation domain in mouse hepatocytes drives hepatocellular carcinoma or hepatoblastoma-like tumor growth

BACKGROUND & AIMS

One-third of hepatocellular carcinomas (HCCs) harbor mutations activating the β-catenin pathway, predominantly via mutations in the CTNNB1 gene itself. Mouse models of Apc loss-of-function are widely used to mimic β-catenin-dependent tumorigenesis. Given the low prevalence of APC mutations in human HCCs, we aimed to generate liver tumors through CTNNB1 exon 3 deletion (βcat^Δex3). We then compared βcat^Δex3 liver tumors with liver tumors generated via frameshift in exon 15 of Apc (Apc^fs-ex15).

METHODS

We used hepatocyte-specific and inducible mouse models generated through either a Cre-Lox or a CRISPR/Cas9 approach using adeno-associated virus vectors. Tumors generated by the Cre-Lox models were phenotypically analyzed using immunohistochemistry and were selected for transcriptomic analysis by RNA-sequencing (RNAseq). Mouse RNAseq data were compared to human RNAseq data (8 normal tissues, 48 HCCs, 9 hepatoblastomas) in an integrative analysis. Tumors generated via CRISPR were analyzed using DNA sequencing and immuno-histochemistry.

RESULTS

Mice with CTNNB1 exon 3 deletion in hepatocytes developed liver tumors indistinguishable from Apc^fs-ex15 liver tumors. Both Apc^fs-ex15 and βcat^Δex3 mouse models induced growth of phenotypically distinct tumors (differentiated or undifferentiated). Integrative analysis of human and mouse tumors showed that differentiated mouse tumors cluster with well-differentiated human CTNNB1-mutated tumors. Conversely, undifferentiated mouse tumors cluster with human mesenchymal hepatoblastomas and harbor activated YAP signaling.

CONCLUSION

Apc^fs-ex15 and βcat^Δex3 mouse models both induce growth of tumors that are transcriptionally similar to either well-differentiated and β-catenin-activated human HCCs or mesenchymal hepatoblastomas.

LAY SUMMARY

New and easy-to-use transgenic mouse models of primary liver cancers have been generated, with mutations in the gene encoding beta-catenin, which are frequent in both adult and pediatric primary liver cancers. The mice develop both types of cancer, constituting a strong preclinical model.

An immune-inflamed tumor microenvironment as defined by CD8 score is associated with favorable oncologic outcomes in hepatocellular carcinoma independent of measures of tumor mutational burden

Despite low mutational burden, immune checkpoint inhibitors have demonstrated promising results in a significant minority of hepatocellular carcinoma (HCC) patients with advanced disease. We hypothesized that HCC patients with higher levels of CD8+ T cell infiltration reflect an immune-inflamed cohort which has improved oncologic outcomes. 355 HCC patients with clinical and transcriptome data in the Cancer Genome Atlas (TCGA) and 151 HCC patients from cohort GSE7624 were analyzed. xCell computational algorithm was used to analyze immune cell infiltration in these patients. Each cohort was divided into high and low expression by the highest 2 terciles value. Gene Set Enrichment Analysis was performed to identify enriched gene sets. High CD8 score associated with improved overall survival in both cohorts (both P < 0.05). High score correlates with early BCLC stage (P = 0.035) but not AJCC stage. High CD8 also correlated with increased IFN-γ response (p = 0.038), lymphocyte infiltration (P < 0.001), and leukocyte fraction (P < 0.001). It was associated with increased polyclonality of T cell (P < 0.001) and B cell response (P = 0.017). High CD8 score correlated with increased cytolytic activity score (P < 0.001) and expression of multiple immune checkpoints including PD-1, PD-L1, CTLA-4 and Lag3 (all P < 0.001). There was no correlation to tumor mutational burden and neoantigens. GSEA demonstrated upregulation of several gene sets involved in inflammatory response and IFN-γ response. In conclusion, HCC patients with high CD8 score demonstrated favorable oncologic outcomes, which may be due to immune-mediated tumor cell attack. Furthermore, CD8 score may be a potentially useful biomarker to select patients for immune checkpoint inhibition.

Correlation of molecular alterations with pathological features in hepatocellular carcinoma: Literature review and experience of an Italian center

Hepatocellular carcinoma (HCC) represents the primary carcinoma of the liver and the fourth leading cause of cancer-related deaths. The World Health Organization estimates an increase in cases in the coming years. The risk factors of HCC are multiple, and the incidence in different countries is closely related to the different risk factors to which the population is exposed. The molecular mechanisms that drive HCC tumorigenesis are extremely complex, but understanding this multistep process is essential for the identification of diagnostic, prognostic, and therapeutic markers. The development of multigenic next-generation sequencing panels through the parallel analysis of multiple markers can provide a landscape of the genomic status of the tumor. Considering the literature and our preliminary data based on 36 HCCs, the most frequently altered genes in HCCs are TERT, CTNNB1, and TP53. Over the years, many groups have attempted to classify HCCs on a molecular basis, but a univocal classification has never been achieved. Nevertheless, statistically significant correlations have been found in HCCs between the molecular signature and morphologic features, and this leads us to think that it would be desirable to integrate the approach between anatomic pathology and molecular laboratories.

MicroRNA-206 enhances antitumor immunity by disrupting the communication between malignant hepatocytes and regulatory T cells in c-Myc mice

BACKGROUND AND AIMS

Intertumoral accumulation of regulatory T cells (Tregs) has been implicated in the pathogenesis of HCC. Because of poor understanding of the immunosuppression mechanism(s) in HCC, immunotherapy is largely unsuccessful for the treatment of HCC.

APPROACH AND RESULTS

Hydrodynamic injection (HDI) of c-Myc into mice resulted in enlarged spleens and lethal HCC associated with an increase in hepatic Tregs and depletion of CTLs (cytotoxic T lymphocytes). Malignant hepatocytes in c-Myc mice overproduced TGFβ1, which enhanced the suppressor function of Tregs and impaired the proliferation and cytotoxicity of CTLs. In addition to activating TGFβ signaling, c-Myc synergized with Yin Yang 1 to impair microRNA-206 (miR-206) biogenesis. HDI of miR-206 fully prevented HCC and the associated enlargement of the spleen, whereas 100% of control mice died from HCC within 5-9 weeks postinjection. Mechanistically, by directly targeting errant kirsten ras oncogene (KRAS) signaling, miR-206 impeded the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) axis that drives expression of Tgfb1. By blocking the KRAS/MEK/ERK axis, miR-206 prevented TGFβ1 overproduction, thereby impairing the suppressor function and expansion of Tregs, but enhancing the expansion and cytotoxic program of CTLs. Disrupting the interaction between miR-206 and Kras offset the roles of miR-206 in inhibiting immunosuppression and HCC. Depletion of CD8⁺ T cells impaired the ability of miR-206 to inhibit HCC.

CONCLUSIONS

c-Myc-educated hepatocytes promoted immunosuppression by overproducing TGFβ1, which promoted HCC development. miR-206, by attenuating TGFβ1 overproduction, disrupted the communication of malignant hepatocytes with CTLs and Tregs, which prevented HCC. miR-206 represents a potential immunotherapeutic agent against HCC.

Co-dependencies in the tumor immune microenvironment

Activated oncogenes and disrupted tumor suppressor genes (TSGs) not only endow aspiring cancer cells with new biological capabilities but also influence the composition and function of host cells in the tumor microenvironment (TME). These non-cancer host cells can in turn provide cancer cells with growth support and protection from the anti-tumor immune response. In this ecosystem, geospatially heterogenous "subTME" adds to the complexity of the "global" TME which bestows tumors with increased tumorigenic ability and resistance to therapy. This review highlights how specific genetic alterations in cancer cells establish various symbiotic co-dependencies with surrounding host cells and details the cooperative role of the host cells in tumor biology. These essential interactions expand the repertoire of targets for the development of precision cancer treatments.

MiR-129-5p exerts Wnt signaling-dependent tumor-suppressive functions in hepatocellular carcinoma by directly targeting hepatoma-derived growth factor HDGF

BACKGROUND

In hepatocellular carcinoma (HCC), histone deacetylases (HDACs) are frequently overexpressed. This results in chromatin compaction and silencing of tumor-relevant genes and microRNAs. Modulation of microRNA expression is a potential treatment option for HCC. Therefore, we aimed to characterize the epigenetically regulated miR-129-5p regarding its functional effects and target genes to understand its relevance for HCC tumorigenesis.

METHODS

Global miRNA expression of HCC cell lines (HLE, HLF, Huh7, HepG2, Hep3B) and normal liver cell lines (THLE-2, THLE-3) was analyzed after HDAC inhibition by miRNA sequencing. An in vivo xenograft mouse model and in vitro assays were used to investigate tumor-relevant functional effects following miR-129-5p transfection of HCC cells. To validate hepatoma-derived growth factor (HDGF) as a direct target gene of miR-129-5p, luciferase reporter assays were performed. Survival data and HDGF expression were analyzed in public HCC datasets. After siRNA-mediated knockdown of HDGF, its cancer-related functions were examined.

RESULTS

HDAC inhibition induced the expression of miR-129-5p. Transfection of miR-129-5p increased the apoptosis of HCC cells, decreased proliferation, migration and ERK signaling in vitro and inhibited tumor growth in vivo. Direct binding of miR-129-5p to the 3'UTR of HDGF via a noncanonical binding site was validated by luciferase reporter assays. HDGF knockdown reduced cell viability and migration and increased apoptosis in Wnt-inactive HCC cells. These in vitro results were in line with the analysis of public HCC datasets showing that HDGF overexpression correlated with a worse survival prognosis, primarily in Wnt-inactive HCCs.

CONCLUSIONS

This study provides detailed insights into the regulatory network of the tumor-suppressive, epigenetically regulated miR-129-5p in HCC. Our results reveal for the first time that the therapeutic application of mir-129-5p may have significant implications for the personalized treatment of patients with Wnt-inactive, advanced HCC by directly regulating HDGF. Therefore, miR-129-5p is a promising candidate for a microRNA replacement therapy to prevent HCC progression and tumor metastasis.

Targeting Wnt/β-Catenin Pathways in Primary Liver Tumours: From Microenvironment Signaling to Therapeutic Agents

Primary liver cancers (PLCs) are steadily increasing in incidence and mortality in the world. They have a poor prognosis due to their silent nature, late discovery and resistance to common chemotherapy. At present, there are limited treatment alternatives, and the understanding of PLC molecular aspects is essential to develop more efficient drugs and therapeutic surgical and loco-regional strategies. A clear causal link with liver damage, inflammation, and regeneration has been found in the occurrence of PLC over the last few decades. Physiologically, Wingless/It (Wnt)-β-catenin signaling plays a key role in liver development, metabolic zonation and regeneration. Loss of functional homeostasis of this pathway appears to be a major driver of carcinogenesis in the liver parenchyma. In the hepatic microenvironment, molecular deregulations that exceed the Wnt signaling biological capacity can induce tumor initiation and progression. Indeed, somatic mutations are identified in key components of canonical and non-canonical Wnt signaling and in PLCs and precancerous lesions. In this review, the altered functions of Wnt/β-catenin signaling are considered in human PLCs, with emphasis on hepatocellular carcinomas (HCC), cholangiocarcinomas (CCA) and hepatoblastomas (HB). Based on recent literature, we also focused on liver cancerogenesis through Wnt deregulation. An overview of preclinical and clinical studies on approved and experimental drugs, targeting the Wnt/β-catenin cascade in PLCs, is proposed. In addition, the clinical implication of molecule inhibitors that have been shown to possess activity against the Wnt pathway in association with conventional surgical and loco-regional therapies are reviewed.

HIV-1-Mediated Acceleration of Oncovirus-Related Non-AIDS-Defining Cancers

With the advent of combination antiretroviral therapy (cART), overall survival has been improved, and the incidence of acquired immunodeficiency syndrome (AIDS)-defining cancers has also been remarkably reduced. However, non-AIDS-defining cancers among human immunodeficiency virus-1 (HIV-1)-associated malignancies have increased significantly so that cancer is the leading cause of death in people living with HIV in certain highly developed countries, such as France. However, it is currently unknown how HIV-1 infection raises oncogenic virus-mediated cancer risks in the HIV-1 and oncogenic virus co-infected patients, and thus elucidation of the molecular mechanisms for how HIV-1 expedites the oncogenic viruses-triggered tumorigenesis in the co-infected hosts is imperative for developing therapeutics to cure or impede the carcinogenesis. Hence, this review is focused on HIV-1 and oncogenic virus co-infection-mediated molecular processes in the acceleration of non-AIDS-defining cancers.

Phosphorylation-Dependent Regulation of WNT/Beta-Catenin Signaling

WNT/β-catenin signaling is a highly complex pathway that plays diverse roles in various cellular processes. While WNT ligands usually signal through their dedicated Frizzled receptors, the decision to signal in a β-catenin-dependent or -independent manner rests upon the type of co-receptors used. Canonical WNT signaling is β-catenin-dependent, whereas non-canonical WNT signaling is β-catenin-independent according to the classical definition. This still holds true, albeit with some added complexity, as both the pathways seem to cross-talk with intertwined networks that involve the use of different ligands, receptors, and co-receptors. β-catenin can be directly phosphorylated by various kinases governing its participation in either canonical or non-canonical pathways. Moreover, the co-activators that associate with β-catenin determine the output of the pathway in terms of induction of genes promoting proliferation or differentiation. In this review, we provide an overview of how protein phosphorylation controls WNT/β-catenin signaling, particularly in human cancer.

The m6A(m)-independent role of FTO in regulating WNT signaling pathways

FTO and ALKBH5 are the two enzymes responsible for mRNA demethylation. Hence, the functional study of FTO has been focused on its mechanistic role in dynamic mRNA modification, and how this post-transcriptional regulation modulates signaling pathways. Here, we report that the functional landscape of FTO is largely associated with WNT signaling pathways but in a manner that is independent of its enzymatic activity. Re-analyses of public datasets identified the bifurcation of canonical and noncanonical WNT pathways as the major role of FTO. In FTO-depleted cells, we find that the canonical WNT/β-Catenin signaling is attenuated in a non-cell autonomous manner via the up-regulation of DKK1. Simultaneously, this up-regulation of DKK1 promotes cell migration via activating the noncanonical WNT/PCP pathway. Unexpectedly, this regulation of DKK1 is independent of its RNA methylation status but operates at the transcriptional level, revealing a noncanonical function of FTO in gene regulation. In conclusion, this study places the functional context of FTO at the branch point of multiple WNT signaling pathways and extends its mechanistic role in gene regulation.

β-Catenin signaling in hepatocellular carcinoma

Deregulated Wnt/β-catenin signaling is one of the main genetic alterations in human hepatocellular carcinoma (HCC). Comprehensive genomic analyses have revealed that gain-of-function mutation of CTNNB1, which encodes β-catenin, and loss-of-function mutation of AXIN1 occur in approximately 35% of human HCC samples. Human HCCs with activation of the Wnt/β-catenin pathway demonstrate unique gene expression patterns and pathological features. Activated Wnt/β-catenin synergizes with multiple signaling cascades to drive HCC formation, and it functions through its downstream effectors. Therefore, strategies targeting Wnt/β-catenin have been pursued as possible therapeutics against HCC. Here, we review the genetic alterations and oncogenic roles of aberrant Wnt/β-catenin signaling during hepatocarcinogenesis. In addition, we discuss the implication of this pathway in HCC diagnosis, classification, and personalized treatment.

Green tea-derived theabrownin induces cellular senescence and apoptosis of hepatocellular carcinoma through p53 signaling activation and bypassed JNK signaling suppression

Background

Theabrownin (TB) is a bioactive component of tea and has been reported to exert effects against many human cancers, but its efficacy and mechanism on hepatocellular carcinoma (HCC) with different p53 genotypes remains unclarified.

Methods

MTT assay, DAPI staining, flow cytometry and SA-β-gal staining were applied to evaluate the effects of TB on HCC cells. Quantitative real time PCR (qPCR) and Western blot (WB) were conducted to explore the molecular mechanism of TB. A xenograft model of zebrafish was established to evaluate the anti-tumor effect of TB.

Results

MTT assays showed that TB significantly inhibited the proliferation of SK-Hep-1, HepG2, and Huh7 cells in a dose-dependent manner, of which SK-Hep-1 was the most sensitive one with the lowest IC50 values. The animal data showed that TB remarkably suppressed SK-Hep-1 tumor growth in xenograft model of zebrafish. The cellular data showed TB's pro-apoptotic and pro-senescent effect on SK-Hep-1 cells. The molecular results revealed the mechanism of TB that p53 signaling pathway (p-ATM, p-ATR, γ-H2AX, p-Chk2, and p-p53) was activated with up-regulation of downstream senescent genes (P16, P21, IL-6 and IL-8) as well as apoptotic genes (Bim, Bax and PUMA) and proteins (Bax, c-Casp9 and c-PARP). The p53-mediated mechanism was verified by using p53-siRNA. Moreover, by using JNK-siRNA, we found JNK as a bypass regulator in TB's mechanism.

Conclusions

To sum up, TB exerted tumor-inhibitory, pro-senescent and pro-apoptotic effects on SK-Hep-1 cells through ATM-Chk2-p53 signaling axis in accompany with JNK bypass regulation. This is the first report on the pro-senescent effect and multi-target (p53 and JNK) mechanism of TB on HCC cells, providing new insights into the underlying mechanisms of TB's anti-HCC efficacy.

Genetic Landscape of Multistep Hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. Although several targeted therapy agents are available for advanced HCC, their antitumor efficacy remains limited. As the complex genetic landscape of HCC would compromise the antitumor efficacy of targeted therapy, a deeper understanding of the genetic landscape of hepatocarcinogenesis is necessary. Recent comprehensive genetic analyses have revealed the driver genes of HCC, which accumulate during the multistage process of hepatocarcinogenesis, facilitating HCC genetic heterogeneity. In addition, as early genetic changes may represent key therapeutic targets, the genetic landscapes of early HCC and precancerous liver tissues have been characterized in recent years, in parallel with the advancement of next-generation sequencing analysis. In this review article, we first summarize the landscape of the liver cancer genome and its intratumor heterogeneity. We then introduce recent insight on early genetic alterations in hepatocarcinogenesis, especially those in early HCC and noncancerous liver tissues. Finally, we summarize the multistep accumulation of genetic aberrations throughout cancer progression and discuss the future perspective towards the clinical application of this genetic information.

Role and Regulation of Wnt/β-Catenin in Hepatic Perivenous Zonation and Physiological Homeostasis

Metabolic heterogeneity or functional zonation is a key characteristic of the liver that allows different metabolic pathways to be spatially regulated within the hepatic system and together contribute to whole body homeostasis. These metabolic pathways are segregated along the portocentral axis of the liver lobule into three hepatic zones: periportal, intermediate or midzonal, and perivenous. The liver performs complementary or opposing metabolic functions within different hepatic zones while synergistic functions are regulated by overlapping zones, thereby maintaining the overall physiological stability. The Wnt/β-catenin signaling pathway is well known for its role in liver growth, development, and regeneration. In addition, the Wnt/β-catenin pathway plays a fundamental and dominant role in hepatic zonation and signals to orchestrate various functions of liver metabolism and pathophysiology. The β-catenin protein is the central player in the Wnt/β-catenin signaling cascade, and its activation is crucial for metabolic patterning of the liver. However, dysregulation of Wnt/β-catenin signaling is also implicated in different liver pathologies, including those associated with metabolic syndrome. β-Catenin is preferentially localized in the central region of the hepatic lobule surrounding the central vein and regulates multiple functions of this region. This review outlines the role of Wnt/β-catenin signaling pathway in controlling the different metabolic processes surrounding the central vein and its relation to liver homeostasis and dysfunction.

3D Culture of Primary Patient-Derived Hepatoblastoma Tumoroids

Hepatoblastoma, the most common primary liver malignancy in children, remains poorly understood due in part to a relative lack of methods to expand tumor cells in culture and a paucity of robust experimental models. Here, we describe a method to obtain primary tumor cells from patients with hepatoblastoma and to propagate the cells in 3D culture as tumor organoids, or "tumoroids". We further detail methods to prepare the tumoroids for whole-mount and cross-sectional imaging as well as to perform lentiviral transduction.

β-catenin plus PROX1 immunostaining stratifies disease progression and patient survival in neoadjuvant-treated pancreatic cancer

BACKGROUND

Wnt/β-catenin signaling is a highly conserved signaling pathway that regulates the transcription factor PROX1. The role of β-catenin and PROX1 in pancreatic cancer is ambiguous, as some studies have associated their expression with tumor regression and some with tumor progression.

OBJECTIVE

We have investigated their expression in surgically treated pancreatic cancer patients receiving neoadjuvant therapy (NAT), and patients treated upfront with surgery (US). We furthermore compared the expression of β-catenin and PROX1 between patients who had a good or poor response to NAT.

METHODS

We evaluated β-catenin and PROX1 expression through immunohistochemistry in 88 neoadjuvant and 144 upfront surgery patients by scoring the intensity of the immunopositivity as 0-3, corresponding to negative, weak, moderate, or strong. We developed a six-tier grading scheme for the neoadjuvant responses by analyzing the remaining tumor cells in surgical specimen histological sections.

RESULTS

Strong β-catenin immunopositivity associated with improved survival in the patients with good NAT-response (≤10% residual tumor cells) (Hazard ratio [HR] 0.26 95%, confidence interval [CI] 0.07-0.88 p = 0.030). Additionally, the combined moderate β-catenin and PROX1 expression associated with improved survival (HR 0.20 95% CI 0.05-0-76 p = 0.018) among the good responders. Among the patients with a poor NAT-response (> 10% residual tumor cells), both strong β-catenin immunopositivity and strong combined β-catenin and PROX1 associated with shorter survival (HR 2.03 95% CI 1.16-3.55 p = 0.013, and HR 3.1 95% CI 1.08-8.94 p = 0.03, respectively). PROX1 alone was not associated with survival.

CONCLUSIONS

Strong β-catenin immunopositivity and combined strong or moderate β-catenin and PROX1 immunopositivity associated with improved survival among the good NAT-responders and worse survival among the poor NAT-responders.

Prognostic Biomarkers in Uveal Melanoma: The Status Quo, Recent Advances and Future Directions

Simple Summary

Although rare, uveal melanoma (UM) is the most common cancer that develops inside adult eyes. The prognosis is poor, since 50% of patients will develop lethal metastases in the first decade, especially to the liver. Once metastases are detected, life expectancy is limited, given that the available treatments are mostly unsuccessful. Thus, there is a need to find methods that can accurately predict UM prognosis and also effective therapeutic strategies to treat this cancer. In this manuscript, we initially compile the current knowledge on epidemiological, clinical, pathological and molecular features of UM. Then, we cover the most relevant prognostic factors currently used for the evaluation and follow-up of UM patients. Afterwards, we highlight emerging molecular markers in UM published over the last three years. Finally, we discuss the problems preventing meaningful advances in the treatment and prognostication of UM patients, as well as forecast new roadblocks and paths of UM-related research.

Abstract

Uveal melanoma (UM) is the most common malignant intraocular tumour in the adult population. It is a rare cancer with an incidence of nearly five cases per million inhabitants per year, which develops from the uncontrolled proliferation of melanocytes in the choroid (≈90%), ciliary body (≈6%) or iris (≈4%). Patients initially present either with symptoms like blurred vision or photopsia, or without symptoms, with the tumour being detected in routine eye exams. Over the course of the disease, metastases, which are initially dormant, develop in nearly 50% of patients, preferentially in the liver. Despite decades of intensive research, the only approach proven to mildly control disease spread are early treatments directed to ablate liver metastases, such as surgical excision or chemoembolization. However, most patients have a limited life expectancy once metastases are detected, since there are limited therapeutic approaches for the metastatic disease, including immunotherapy, which unlike in cutaneous melanoma, has been mostly ineffective for UM patients. Therefore, in order to offer the best care possible to these patients, there is an urgent need to find robust models that can accurately predict the prognosis of UM, as well as therapeutic strategies that effectively block and/or limit the spread of the metastatic disease. Here, we initially summarized the current knowledge about UM by compiling the most relevant epidemiological, clinical, pathological and molecular data. Then, we revisited the most important prognostic factors currently used for the evaluation and follow-up of primary UM cases. Afterwards, we addressed emerging prognostic biomarkers in UM, by comprehensively reviewing gene signatures, immunohistochemistry-based markers and proteomic markers resulting from research studies conducted over the past three years. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues of research in UM.

Nuclear Expression of Pygo2 Correlates with Poorly Differentiated State Involving c-Myc, PCNA and Bcl9 in Myanmar Hepatocellular Carcinoma

In Myanmar, hepatocellular carcinoma (HCC) is commonly seen in young adult and associated with poor prognosis, while the molecular mechanisms that characterize HCC in Myanmar are unknown. As co-activation of Wnt/β-catenin signaling and c-Myc (Myc) are reported to associate with malignancy of HCC, we immunohistochemically investigated the expression of Pygo2 and Bcl9, the co-activators of the Wnt/β-catenin signaling, Myc and PCNA in 60 cases of Myanmar HCC. Pygo2 expression was confirmed by in situ hybridization. The signal intensity was measured by image analyzer and then statistically analyzed. As a result, the expression of Pygo2 was significantly higher in HCC compared to normal liver tissue and the nuclear signal was the most intense in poorly differentiated HCC. Cytoplasmic Bcl9 was expressed in the normal liver tissue but decreased in HCC with the progression of histopathological grade. Myc was significantly higher in poorly differentiated HCC, whereas PCNA labeling index increased with the progression of histopathological grade. Nuclear Pygo2 showed strong correlation with nuclear Myc (P < 0.01) and PCNA (P < 0.001), and inversely correlated with cytoplasmic Bcl9 (P < 0.01). Our results suggested Wnt/β-catenin and Myc signaling is commonly activated in Myanmar HCC and that the correlative upregulation of nuclear Pygo2 and Myc characterizes the malignant features of HCC in Myanmar.

Personalized circulating tumor DNA in patients with hepatocellular carcinoma: a pilot study

BACKGROUND

Mutational analysis of circulating tumor DNA (ctDNA) can potentially be used for early detection of recurrence after resection for hepatocellular carcinoma (HCC). Mutations from tumor may be identified in plasma as an early sign of recurrence. We conducted a pilot study investigating if somatic mutations could be detected in plasma in patients undergoing liver resection for HCC and in patients with advanced non-resectable HCC.

METHODS AND RESULTS

We prospectively included patients undergoing curative liver resection for HCC. Tumor tissue was investigated with whole exome sequencing and preoperative blood samples were evaluated for ctDNA using targeted next-generation sequencing (NGS) with TruSight Oncology 500 including 523 cancer-associated genes. Subsequently, the method was evaluated in patients with advanced HCC. We included eight patients curatively resected for HCC, where tumor tissue mutations were identified in seven patients. However, only in one patient tumor specific mutations were found in the preoperative blood sample. In all three patients with advanced HCC, tumor mutations were detected in the blood.

CONCLUSIONS

In patients with resectable HCC, ctDNA could not be reliably detected using the applied targeted NGS method. In contrast, ctDNA was detected in all patients with advanced HCC. Small tumors, tumor heterogeneity and limited sequencing coverage may explain the lack of detectable ctDNA.

Babao Dan is a robust anti-tumor agent via inhibiting wnt/β-catenin activation and cancer cell stemness

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese Medicine (TCM) is being increasingly used worldwide due to its diverse efficacy and relatively low side effects. Babao Dan (BBD) is a well-known TCM formula that is currently used for the effective treatment of various cancers, however its underlying molecular mechanism remains unknown.

AIM OF THE STUDY

Tumor growth and tumor recurrence are characterized by two distinct populations of cells, namely the well-differentiated cancer cells composing the majority of tumor bulk, and cancer stem cells (CSCs) involved in tumor relapse, which are both strongly associated with excessive activation of Wnt/β-catenin signaling. Our study aims to elucidate the underlying molecular mechanisms associated with the anti-tumor proliferative effects of Babao Dan (BBD).

MATERIALS AND METHODS

We used a hepatoblastoma cell line HepG2 with stem cell-like traits that harbors a constitutively active mutant of β-catenin in order to study the anti-tumor ability of BBD via targeting Wnt/β-catenin signaling.

RESULTS

BBD robustly attenuated both the intrinsic and extrinsic activation of Wnt/β-catenin pathway in HepG2 hepatoblastoma cells, as well as Wnt target genes. Moreover, BBD significantly inhibited both the proliferation of well-differentiated cancer cells, as well as the stem-like property of CSCs as evidenced by EpCAM, a Wnt target gene and a novel marker of cancer cell stemness. In addition, mice administered with BBD using HepG2 cell line derived xenograft model had marked reductions in tumor size and weight, as well as significantly decreased expressions of Wnt target genes and cancer cell stemness.

CONCLUSION

Our findings elucidated the underlying molecular mechanisms associated with the robust anti-tumor effects of BBD via potent inhibition of Wnt/β-catenin signaling, and implicate its use in the clinical treatment of cancers.

The protein kinase activity of NME7 activates Wnt/β-Catenin signaling to promote one-carbon metabolism in hepatocellular carcinoma

Metabolic reprogramming by oncogenic signaling is a hallmark of cancer. Hyperactivation of Wnt/β-catenin signaling has been reported in hepatocellular carcinoma (HCC). However, the mechanisms inducing hyperactivation of Wnt/β-catenin signaling and strategies for targeting this pathway are incompletely understood. In this study, we find nucleoside diphosphate kinase 7 (NME7) to be a positive regulator of Wnt/β-catenin signaling. Upregulation of NME7 positively correlated with the clinical features of HCC. Knockdown of NME7 inhibited HCC growth in vitro and in vivo, while overexpression of NME7 cooperated with c-Myc to drive tumorigenesis in a mouse model and promote the growth of tumor-derived organoids. Mechanistically, NME7 bound and phosphorylated serine 9 of GSK3β to promote β-catenin activation. Furthermore, MTHFD2, the key enzyme in one-carbon metabolism, was a target gene of β-catenin and mediated the effects of NME7. Tumor-derived organoids with NME7 overexpression exhibited increased sensitivity to MTHFD2 inhibition. Additionally, expression levels of NME7, β-catenin and MTHFD2 correlated with each other and with poor prognosis in HCC patients. Collectively, this study emphasizes the crucial roles of NME7 protein kinase activity in promoting Wnt/β-catenin signaling and one-carbon metabolism, suggesting NME7 and MTHFD2 as potential therapeutic targets for HCC.