Axin2+ Peribiliary Glands in the Periampullary Region Generate Biliary Epithelial Stem Cells That Give Rise to Ampullary Carcinoma

Ampullary tumors exhibit increased Fusobacterium in both the tumor surface and surrounding duodenal mucosa during carcinoma progression

Understanding the complex interplay between intestinal microbiomes and ampullary tumors is crucial for distinguishing between adenomas and carcinomas, especially when considering the role of Fusobacterium. We characterized the microbiome associated with ampullary tumors using samples collected from the tumor surface (tumor samples, TSs) and surrounding normal duodenal mucosa (normal samples, NSs) via brush rubbing. In total, samples from 17 patients, divided into an adenoma group (n = 11) and a carcinoma group (n = 6), were analyzed. The Shannon α-diversity index was significantly higher in the carcinoma group compared with the adenoma group, indicating a more diverse bacterial community in the carcinoma environment. The TSs of the carcinoma group exhibited enrichment of Fusobacterium, Leptotrichia, Methylorubrum, and Micrococcus. The relative abundance of Fusobacterium increased as the tumor progressed. The NSs of the carcinoma group showed a higher presence of Fusobacterium, Porphyromonas, Granulicatella, Rikenellaceae RC9 gut group, and Solobacterium, whereas Bergeyella was more prevalent in the adenoma group. These results suggest that ampullary carcinomas exhibit a characteristic microbiome compared to adenomas. Fusobacterium is enriched in the tumor and surrounding normal duodenal mucosa, increases in abundance as the tumor progresses, and may be associated with ampullary tumors.

Morphomolecular Pathology and Genomic Insights into the Cells of Origin of Cholangiocarcinoma and Combined Hepatocellular-Cholangiocarcinoma

Cholangiocarcinomas are a highly heterogeneous group of malignancies that, despite recent progress in the understanding of their molecular pathogenesis and clinical management, continue to pose a major challenge to public health. The traditional view posits that cholangiocarcinomas derive from the neoplastic transformation of cholangiocytes lining the biliary tree. However, increasing genetic and experimental evidence has recently pointed to a more complex, and nuanced, scenario for the potential cell of origin of cholangiocarcinomas. Hepatocytes as well as hepatic stem/progenitor cells are being considered as additional potential sources, depending on microenvironmental contexts, including liver injury. The hypothesis of potentially diverse cells of origin for cholangiocarcinoma, albeit controversial, is certainly not surprising given the plasticity of the cells populating the liver as well as the existence of liver cancer subtypes with mixed histologic and molecular features. This review carefully examines the current pathologic, genomic, and experimental evidence supporting the existence of multiple cells of origin of liver and biliary tract cancers, with particular focus on cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma.

WNT signaling contributes to the extrahepatic bile duct proliferative response to obstruction in mice

Biliary obstruction and cholangiocyte hyperproliferation are important features of cholangiopathies affecting the large extrahepatic bile duct (EHBD). The mechanisms underlying obstruction-induced cholangiocyte proliferation in the EHBD remain poorly understood. Developmental pathways, including WNT signaling, are implicated in regulating injury responses in many tissues, including the liver. To investigate the contribution of WNT signaling to obstruction-induced cholangiocyte proliferation in the EHBD, we used complementary in vivo and in vitro models with pharmacologic interventions and transcriptomic analyses. To model obstruction, we used bile duct ligation (BDL) in mice. Human and mouse biliary organoids and mouse biliary explants were used to investigate the effects of WNT activation and inhibition in vitro. We observed an upregulation of WNT ligand expression associated with increased biliary proliferation following obstruction. Cholangiocytes were identified as both WNT ligand-expressing and WNT-responsive cells. Inhibition of WNT signaling decreased cholangiocyte proliferation in vivo and in vitro, while activation increased proliferation. WNT effects on cholangiocyte proliferation were β-catenin dependent, and we showed a direct effect of WNT7B on cholangiocyte growth. Our studies suggested that cholangiocyte-derived WNT ligands can activate WNT signaling to induce proliferation after obstructive injury. These findings implicate the WNT pathway in injury-induced cholangiocyte proliferation within the EHBD.

Pkd1l1-deficiency drives biliary atresia through ciliary dysfunction in biliary epithelial cells

BACKGROUND & AIMS

Syndromic biliary atresia is a cholangiopathy characterized by fibro-obliterative changes in the extrahepatic bile duct (EHBD) and congenital malformations including laterality defects. The etiology remains elusive and faithful animal models are lacking. Genetic syndromes provide important clues regarding the pathogenic mechanisms underlying the disease. We investigated the role of the gene Pkd1l1 in the pathophysiology of syndromic biliary atresia.

METHODS

Constitutive and conditional Pkd1l1 knockout mice were generated to explore genetic pathology as a cause of syndromic biliary atresia. We investigated congenital malformations, EHBD and liver pathology, EHBD gene expression, and biliary epithelial cell turnover. Biliary drainage was functionally assessed with cholangiography. Histology and serum chemistries were assessed after DDC (3,5-diethoxycarbony l-1,4-dihydrocollidine) diet treatment and inhibition of the ciliary signaling effector GLI1.

RESULTS

Pkd1l1-deficient mice exhibited congenital anomalies including malrotation and heterotaxy. Pkd1l1-deficient EHBDs were hypertrophic and fibrotic. Pkd1l1-deficient EHBDs were patent but displayed delayed biliary drainage. Pkd1l1-deficient livers exhibited ductular reaction and periportal fibrosis. After DDC treatment, Pkd1l1-deficient mice exhibited EHBD obstruction and advanced liver fibrosis. Pkd1l1-deficient mice had increased expression of fibrosis and extracellular matrix remodeling genes (Tgfα, Cdkn1a, Hb-egf, Fgfr3, Pdgfc, Mmp12, and Mmp15) and decreased expression of genes mediating ciliary signaling (Gli1, Gli2, Ptch1, and Ptch2). Primary cilia were reduced on biliary epithelial cells and altered expression of ciliogenesis genes occurred in Pkd1l1-deficient mice. Small molecule inhibition of the ciliary signaling effector GLI1 with Gant61 recapitulated Pkd1l1-deficiency.

CONCLUSIONS

Pkd1l1 loss causes both laterality defects and fibro-proliferative EHBD transformation through disrupted ciliary signaling, phenocopying syndromic biliary atresia. Pkd1l1-deficient mice function as an authentic genetic model for study of the pathogenesis of biliary atresia.

IMPACT AND IMPLICATIONS

The syndromic form of biliary atresia is characterized by fibro-obliteration of extrahepatic bile ducts and is often accompanied by laterality defects. The etiology is unknown, but Pkd1l1 was identified as a potential genetic candidate for syndromic biliary atresia. We found that loss of the ciliary gene Pkd1l1 contributes to hepatobiliary pathology in biliary atresia, exhibited by bile duct hypertrophy, reduced biliary drainage, and liver fibrosis in Pkd1l1-deficient mice. Pkd1l1-deficient mice serve as a genetic model of biliary atresia and reveal ciliopathy as an etiology of biliary atresia. This model will help scientists uncover new therapeutic approaches for patients with biliary atresia, while pediatric hepatologists should validate the diagnostic utility of PKD1L1 variants.

PTEN deficiency induces an extrahepatic cholangitis-cholangiocarcinoma continuum via aurora kinase A in mice

BACKGROUND & AIMS

The PTEN-AKT pathway is frequently altered in extrahepatic cholangiocarcinoma (eCCA). We aimed to evaluate the role of PTEN in the pathogenesis of eCCA and identify novel therapeutic targets for this disease.

METHODS

The Pten gene was genetically deleted using the Cre-loxp system in biliary epithelial cells. The pathologies were evaluated both macroscopically and histologically. The characteristics were further analyzed by immunohistochemistry, reverse-transcription PCR, cell culture, and RNA sequencing. Some features were compared to those in human eCCA samples. Further mechanistic studies utilized the conditional knockout of Trp53 and Aurora kinase A (Aurka) genes. We also tested the effectiveness of an Aurka inhibitor.

RESULTS

We observed that genetic deletion of the Pten gene in the extrahepatic biliary epithelium and peri-ductal glands initiated sclerosing cholangitis-like lesions in mice, resulting in enlarged and distorted extrahepatic bile ducts in mice as early as 1 month after birth. Histologically, these lesions exhibited increased epithelial proliferation, inflammatory cell infiltration, and fibrosis. With aging, the lesions progressed from low-grade dysplasia to invasive carcinoma. Trp53 inactivation further accelerated disease progression, potentially by downregulating senescence. Further mechanistic studies showed that both human and mouse eCCA showed high expression of AURKA. Notably, the genetic deletion of Aurka completely eliminated Pten deficiency-induced extrahepatic bile duct lesions. Furthermore, pharmacological inhibition of Aurka alleviated disease progression.

CONCLUSIONS

Pten deficiency in extrahepatic cholangiocytes and peribiliary glands led to a cholangitis-to-cholangiocarcinoma continuum that was dependent on Aurka. These findings offer new insights into preventive and therapeutic interventions for extrahepatic CCA.

IMPACT AND IMPLICATIONS

The aberrant PTEN-PI3K-AKT signaling pathway is commonly observed in human extrahepatic cholangiocarcinoma (eCCA), a disease with a poor prognosis. In our study, we developed a mouse model mimicking cholangitis to eCCA progression by conditionally deleting the Pten gene via Pdx1-Cre in epithelial cells and peribiliary glands of the extrahepatic biliary duct. The conditional Pten deletion in these cells led to cholangitis, which gradually advanced to dysplasia, ultimately resulting in eCCA. The loss of Pten heightened Akt signaling, cell proliferation, inflammation, fibrosis, DNA damage, epigenetic signaling, epithelial-mesenchymal transition, cell dysplasia, and cellular senescence. Genetic deletion or pharmacological inhibition of Aurka successfully halted disease progression. This model will be valuable for testing novel therapies and unraveling the mechanisms of eCCA tumorigenesis.

Emerging targeted therapies and strategies to overcome resistance in biliary tract cancers

In the last decade, targeted therapies have shown rapid advancement in biliary tract cancer (BTC). Today, many targeted agents are available and under investigation for patients with BTC. More recently, immune checkpoint inhibitors (ICI) such as durvalumab and pembrolizumab in combination with gemcitabine plus cisplatin (gem/cis) have resulted in improved overall survival and progression-free survival in the first-line setting. However, the efficacy benefit of these novel therapeutics is often short-lived, with literature outlining concerns about both primary and secondary resistance to these agents. Investigators also need to consider toxicity profiles that can emerge using this strategy. There have been efforts to reduce evolving resistance through combinatory approaches, both pre-clinically and in early clinical settings. This review summarizes the emerging targeted therapies in BTC, evolving biomarkers of resistance, strategies to overcome them, and an analysis of ongoing clinical trials of patients with advanced BTC.

Generation of in vivo-like multicellular liver organoids by mimicking developmental processes: A review

Liver is involved in metabolic reactions, ammonia detoxification, and immunity. Multicellular liver tissue cultures are more desirable for drug screening, disease modeling, and researching transplantation therapy, than hepatocytes monocultures. Hepatocytes monocultures are not stable for long. Further, hepatocyte-like cells induced from pluripotent stem cells and in vivo hepatocytes are functionally dissimilar. Organoid technology circumvents these issues by generating functional ex vivo liver tissue from intrinsic liver progenitor cells and extrinsic stem cells, including pluripotent stem cells. To function as in vivo liver tissue, the liver organoid cells must be arranged precisely in the 3-dimensional space, closely mimicking in vivo liver tissue. Moreover, for long term functioning, liver organoids must be appropriately vascularized and in contact with neighboring epithelial tissues (e.g., bile canaliculi and intrahepatic bile duct, or intrahepatic and extrahepatic bile ducts). Recent discoveries in liver developmental biology allows one to successfully induce liver component cells and generate organoids. Thus, here, in this review, we summarize the current state of knowledge on liver development with a focus on its application in generating different liver organoids. We also cover the future prospects in creating (functionally and structurally) in vivo-like liver organoids using the current knowledge on liver development.

Biliary stem cells in health and cholangiopathies and cholangiocarcinoma

PURPOSE OF REVIEW

This review discusses evidence regarding progenitor populations of the biliary tree in the tissue regeneration and homeostasis, and the pathobiology of cholangiopathies and malignancies.

RECENT FINDINGS

In embryogenesis biliary multipotent progenitor subpopulation contributes cells not only to the pancreas and gall bladder but also to the liver. Cells equipped with a constellation of markers suggestive of the primitive endodermal phenotype exist in the peribiliary glands, the bile duct glands, of the intra- and extrahepatic bile ducts. These cells are able to be isolated and cultured easily, which demonstrates the persistence of a stable phenotype during in vitro expansion, the ability to self-renew in vitro, and the ability to differentiate between hepatocyte and biliary and pancreatic islet fates.

SUMMARY

In normal human livers, stem/progenitors cells are mostly restricted in two distinct niches, which are the bile ductules/canals of Hering and the peribiliary glands (PBGs) present inside the wall of large intrahepatic bile ducts. The existence of a network of stem/progenitor cell niches within the liver and along the entire biliary tree inform a patho-biological-based translational approach to biliary diseases and cholangiocarcinoma since it poses the basis to understand biliary regeneration after extensive or chronic injuries and progression to fibrosis and cancer.

Heterogeneous murine peribiliary glands orchestrate compartmentalized epithelial renewal

The extrahepatic branches of the biliary tree have glands that connect to the surface epithelium through narrow pits. The duct epithelia undergo homeostatic renewal, yet the identity and multiplicity of cells that maintain this tissue is unknown. Using marker-free and targeted clonal fate mapping in mice, we provide evidence that the extrahepatic bile duct is compartmentalized. Pit cholangiocytes of extramural glands renewed the surface epithelium, whereas basally oriented cholangiocytes maintained the gland itself. In contrast, basally positioned cholangiocytes replenished the surface epithelium in mural glands. Single-cell sequencing identified genes enriched in the base and surface epithelial populations, with trajectory analysis showing graded gene expression between these compartments. Epithelia were plastic, changing cellular identity upon fasting and refeeding. Gain of canonical Wnt signaling caused basal cell expansion, gastric chief cell marker expression, and a decrease in surface epithelial markers. Our results identify the cellular hierarchy governing extrahepatic biliary epithelial renewal.

Panic at the Bile Duct: How Intrahepatic Cholangiocytes Respond to Stress and Injury

In the liver, biliary epithelial cells (BECs) line intrahepatic bile ducts (IHBDs) and are primarily responsible for modifying and transporting hepatocyte-produced bile to the digestive tract. BECs comprise only 3% to 5% of the liver by cell number but are critical for maintaining choleresis through homeostasis and disease. To this end, BECs drive an extensive morphologic remodeling of the IHBD network termed ductular reaction (DR) in response to direct injury or injury to the hepatic parenchyma. BECs are also the target of a broad and heterogenous class of diseases termed cholangiopathies, which can present with phenotypes ranging from defective IHBD development in pediatric patients to progressive periductal fibrosis and cancer. DR is observed in many cholangiopathies, highlighting overlapping similarities between cell- and tissue-level responses by BECs across a spectrum of injury and disease. The following core set of cell biological BEC responses to stress and injury may moderate, initiate, or exacerbate liver pathophysiology in a context-dependent manner: cell death, proliferation, transdifferentiation, senescence, and acquisition of neuroendocrine phenotype. By reviewing how IHBDs respond to stress, this review seeks to highlight fundamental processes with potentially adaptive or maladaptive consequences. A deeper understanding of how these common responses contribute to DR and cholangiopathies may identify novel therapeutic targets in liver disease.

New Era of Immune-Based Therapy in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (CC) accounts for approximately 20% of all biliary tract cancer (BTC) cases and 10-15% of all primary liver cancer cases. Many patients are diagnosed with unresectable BTC, and, even among patients with resectable BTC, the 5-year survival rate is approximately 20%. The BTC incidence rate is high in Southeast and East Asia and has increased worldwide in recent years. Since 2010, cytotoxic chemotherapy, particularly combination gemcitabine + cisplatin (ABC-02 trial), has been the first-line therapy for patients with BTC. In 2022, a multicenter, double-blind, randomized phase 3 trial (TOPAZ-1 trial) examined the addition of programmed death-ligand 1 immunotherapy (durvalumab) to combination gemcitabine + cisplatin for BTC treatment, resulting in significantly improved survival without notable additional toxicity. As a result of this trial, this three-drug combination has become the new standard first-line therapy, leading to notable advances in BTC management for the first time since 2010. The molecular profiling of BTC has continued to drive the development of new targeted therapies for use when first-line therapies fail. Typically, second-line therapy decisions are based on identified genomic alterations in tumor tissue. Mutations in fibroblast growth factor receptor 1/2/3, isocitrate dehydrogenase 1/2, and neurotrophic tyrosine receptor kinase A/B/C are relatively frequent in intrahepatic CC, and precision medicines are available that can target associated pathways. In this review, we suggest strategies for systemic pharmacotherapy with a focus on intrahepatic CC, in addition to presenting the results and safety outcomes of clinical trials evaluating immune checkpoint inhibitor therapies in BTC.

Discovery of the radio-protecting effect of Ecliptae Herba, its constituents and targeting p53-mediated apoptosis in vitro and in vivo

Radiation protection drugs are often accompanied by toxicity, even amifostine, which has been the dominant radio-protecting drug for nearly 30 years. Furthermore, there is no therapeutic drug for radiation-induced intestinal injury (RIII). This paper intends to find a safe and effective radio-protecting ingredient from natural sources. The radio-protecting effect of Ecliptae Herba (EHE) was discovered preliminarily by antioxidant experiments and the mouse survival rate after ¹³⁷Cs irradiation. EHE components and blood substances in vivo were identified through UPLC‒Q-TOF. The correlation network of "natural components in EHE-constituents migrating to blood-targets-pathways" was established to predict the active components and pathways. The binding force between potential active components and targets was studied by molecular docking, and the mechanism was further analyzed by Western blotting, cellular thermal shift assay (CETSA), and ChIP. Additionally, the expression levels of Lgr5, Axin2, Ki67, lysozyme, caspase-3, caspase-8,8-OHdG, and p53 in the small intestine of mice were detected. It was found for the first time that EHE is active in radiation protection and that luteolin is the material basis of this protection. Luteolin is a promising candidate for RⅢ. Luteolin can inhibit the p53 signaling pathway and regulate the BAX/BCL2 ratio in the process of apoptosis. Luteolin could also regulate the expression of multitarget proteins related to the same cell cycle.

Cellular and transcriptional heterogeneity in the intrahepatic biliary epithelium

Epithelial tissues comprise heterogeneous cellular subpopulations, which often compartmentalize specialized functions like absorption and secretion to distinct cell types. In the liver, hepatocytes and biliary epithelial cells (BECs; also called cholangiocytes) are the two major epithelial lineages and play distinct roles in (1) metabolism, protein synthesis, detoxification, and (2) bile transport and modification, respectively. Recent technological advances, including single cell transcriptomic assays, have shed new light on well-established heterogeneity among hepatocytes, endothelial cells, and immune cells in the liver. However, a "ground truth" understanding of molecular heterogeneity in BECs has remained elusive, and the field currently lacks a set of consensus biomarkers for identifying BEC subpopulations. Here, we review long-standing definitions of BEC heterogeneity as well as emerging studies that aim to characterize BEC subpopulations using next generation single cell assays. Understanding cellular heterogeneity in the intrahepatic bile ducts holds promise for expanding our foundational mechanistic knowledge of BECs during homeostasis and disease.

Remission from the 5-Fu-Based Chemotherapy to Gemcitabine-Based Chemotherapy-Based on the Pathological Classification of Periampullary Carcinoma: A Case Report and Literature Review

Background

Periampullary carcinoma, which includes ampullary carcinoma, pancreatic head cancer, distal common bile duct cancer, and duodenal papillary cancer, is a relatively rare malignancy with uncertain therapeutic options. Although several studies have investigated the efficacy of multiple adjuvant chemotherapy regimens for periampullary carcinoma treatment, the optimal regimen remains to be determined. The inherent heterogeneity of the mucosal origin divides periampullary carcinoma into intestinal and pancreaticobiliary types. Therefore, the selection of chemotherapy regimens based on pathological type may have potential therapeutic significance.

Case Presentation

A 72-year-old woman with moderately differentiated periampullary adenocarcinoma experienced disease progression after receiving FOLFOX regimen. Subsequently, the sample was subtyped first by H&E evaluation and then by the evaluation of an IHC panel composed of CK20, CDX2, MUC1, MUC2, and MUC5AC. The pathologists concluded that the patient’s sample was of the pancreaticobiliary (PB) subtype. The subsequent change to gemcitabine plus S-1 adjuvant therapy achieved remission of liver metastases based on the pathological classification of the cancer.

Conclusion

Based on the pathological classification, adjuvant chemotherapy with gemcitabine may be beneficial for patients with PB subtype periampullary carcinoma. 5-Fu-based adjuvant chemotherapy may be beneficial for patients with intestinal subtype periampullary carcinoma.

Cellular Homeostasis and Repair in the Biliary Tree

During biliary tree homeostasis, BECs are largely in a quiescent state and their turnover is slow for maintaining normal tissue homeostasis. BTSCs continually replenish new BECs in the luminal surface of EHBDs. In response to various types of biliary injuries, distinct cellular sources, including HPCs, BTSCs, hepatocytes, and BECs, repair or regenerate the injured bile duct. BEC, biliary epithelial cell; BTSC, biliary tree stem/progenitor cell; EHBD, extrahepatic bile ducts; HPC, hepatic progenitor cell.The biliary tree comprises intrahepatic bile ducts and extrahepatic bile ducts lined with epithelial cells known as biliary epithelial cells (BECs). BECs are a common target of various cholangiopathies for which there is an unmet therapeutic need in clinical hepatology. The repair and regeneration of biliary tissue may potentially restore the normal architecture and function of the biliary tree. Hence, the repair and regeneration process in detail, including the replication of existing BECs, expansion and differentiation of the hepatic progenitor cells and biliary tree stem/progenitor cells, and transdifferentiation of the hepatocytes, should be understood. In this paper, we review biliary tree homeostasis, repair, and regeneration and discuss the feasibility of regenerative therapy strategies for cholangiopathy treatment.

Multimodal data analysis reveals that pancreatobiliary-type ampullary adenocarcinoma resembles pancreatic adenocarcinoma and differs from cholangiocarcinoma

BACKGROUND

Ampullary adenocarcinoma (AAC) arises from the ampulla of Vater where the pancreatic duct and bile duct join and empty into the duodenum. It can be classified into intestinal and pancreatobiliary types based on histopathology or immunohistochemistry. However, there are no biomarkers for further classification of pancreatobiliary-type AAC which has important implications for its treatment. We aimed to identify the tumor origin of pancreatobiliary-type AAC by systematically analyzing whole-slide images (WSIs), survival data, and genome sequencing data collected from multiple centers.

METHODS

This study involved three experiments. First, we extracted quantitative and highly interpretable features from the tumor region in WSIs and constructed a histologic classifier to differentiate between pancreatic adenocarcinoma (PAC) and cholangiocarcinoma. The histologic classifier was then applied to patients with pancreatobiliary-type AAC to infer the tumor origin. Secondly, we compared the overall survival of patients with pancreatobiliary-type AAC stratified by the adjuvant chemotherapy regimens designed for PAC or cholangiocarcinoma. Finally, we compared the mutation landscape of pancreatobiliary-type AAC with those of PAC and cholangiocarcinoma.

RESULTS

The histologic classifier accurately classified PAC and cholangiocarcinoma in both the internal and external validation sets (AUC > 0.99). All pancreatobiliary-type AACs (n = 45) were classified as PAC. The patients with pancreatobiliary-type AAC receiving regimens designed for PAC showed more favorable overall survival than those receiving regimens designed for cholangiocarcinoma in a multivariable Cox regression (hazard ratio = 7.24, 95% confidence interval: 1.28-40.78, P = 0.025). The results of mutation analysis showed that the mutation landscape of AAC was very similar to that of PAC but distinct from that of cholangiocarcinoma.

CONCLUSIONS

This multi-center study provides compelling evidence that pancreatobiliary-type AAC resembles PAC instead of cholangiocarcinoma in different aspects, which can guide the treatment selection and clinical trials planning for pancreatobiliary-type AAC.

Analysis of 5-Methylcytosine Regulators and DNA Methylation-Driven Genes in Colon Cancer

Background: Epigenetic-driven events are important molecular mechanisms of carcinogenesis. The 5-methylcytosine (5mC) regulators play important roles in the methylation-driven gene expression. However, the effect of the 5mC regulators on the oncogenic pathways in colon cancer (CC) remains unclear. Also, the clinical value of such epigenetic-driven events needs further research.

Methods: The transcriptome and matching epigenetic data were obtained from The Cancer Genome Atlas dataset. The gene set variation analysis identified the oncogenic pathways adjusted by 5mC regulators. The “edgeR” and “methylmix” package identified the differential expression genes of DNA methylation-driven genes. The correlation between 5mC regulators or transcription factors and shortlisted genes was investigated by calculating the Spearman's rank correlation coefficient. Among them, the genes related to diagnosis were screened out based on differential gene expression in extracellular vesicles (EVs) by the “limma” package and histology by immunohistochemistry. Then, a risk signature was constructed by fitting the generalized linear model and validated by the receiver operating characteristic curve.

Results: MYC targets pathway and phosphatidylinositol-3-kinase–AKT–mammalian target of rapamycin signaling pathway were identified as the hallmark-related pathways associated with 5mC regulators. Also, the P53 pathway was subject to the influence of regulators' expression. A five methylation-driven gene signature (FIRRE, MYBL2, TGFBI, AXIN2, and SLC35D3) was developed as the biomarker for CC diagnosis. Meanwhile, those genes positively related to 5mC regulators and interacted with their relevant or transcription factors.

Conclusion: In general, 5mC regulators are positively related to each other and DNA methylation-driven genes, with the relationship of multiple active and inhibitory pathways related to cancer. Meanwhile, the signature (FIRRE, MYBL2, TGFBI, AXIN2, and SLC35D3) can prefigure prospective diagnosis in CC.

Cell fate analysis of zone 3 hepatocytes in liver injury and tumorigenesis

BACKGROUND & AIMS

Liver lobules are typically subdivided into 3 metabolic zones: zones 1, 2, and 3. However, the contribution of zonal differences in hepatocytes to liver regeneration, as well as to carcinogenic susceptibility, remains unclear.

METHODS

We developed a new method for sustained genetic labelling of zone 3 hepatocytes and performed fate tracing to monitor these cells in multiple mouse liver tumour models.

RESULTS

We first examined changes in the zonal distribution of the Wnt target gene Axin2 over time using Axin2-Cre ERT2 ;Rosa26-Lox-Stop-Lox-tdTomato mice (Axin2;tdTomato). We found that following tamoxifen administration at 3 weeks of age, approximately one-third of total hepatocytes that correspond to zone 3 were labelled in Axin2;tdTomato mice; the tdTomato+ cell distribution closely matched that of the zone 3 marker CYP2E1. Cell fate analysis revealed that zone 3 hepatocytes maintained their own lineage but rarely proliferated beyond their liver zonation during homoeostasis; this indicated that our protocol enabled persistent genetic labelling of zone 3 hepatocytes. Using this system, we found that zone 3 hepatocytes generally had high neoplastic potential, which was promoted by constitutive activation of Wnt/β-catenin signalling in the pericentral area. However, the frequency of zone 3 hepatocyte-derived tumours varied depending on the regeneration pattern of the liver parenchyma in response to liver injury. Notably, Axin2-expressing hepatocytes undergoing chronic liver injury significantly contributed to liver regeneration and possessed high neoplastic potential. Additionally, we revealed that the metabolic phenotypes of liver tumours were acquired during tumorigenesis, irrespective of their spatial origin.

CONCLUSIONS

Hepatocytes receiving Wnt/β-catenin signalling from their microenvironment have high neoplastic potential, and Wnt/β-catenin signalling is a potential drug target for the prevention of hepatocellular carcinoma.

LAY SUMMARY

Lineage tracing revealed that zone 3 hepatocytes residing in the pericentral niche have high neoplastic potential. Under chronic liver injury, hepatocytes receiving Wnt/β-catenin signalling broadly exist across all hepatic zones and significantly contribute to liver tumorigenesis as well as liver regeneration. Wnt/β-catenin signalling is a potential drug target for the prevention of hepatocellular carcinoma.