Epigenetic footprint enables molecular risk stratification of hepatoblastoma with clinical implications

Gas1-Mediated Suppression of Hepatoblastoma Tumorigenesis

Hepatoblastoma (HB), the most common pediatric liver cancer, is associated with dysregulated Wnt/β-catenin, Hippo, and/or nuclear factor erythroid 2 ligand 2/nuclear respiratory factor 2 (NFE2L2/NRF2) pathways. In mice, pairwise combinations of oncogenically active forms of the terminal transcription factors of these pathways, namely, β-catenin (B), Yes-associated protein (YAP; Y), and Nrf2 (N), generate HBs, with the triple combination (B + Y + N) being particularly potent. Each tumor group alters the expression of thousands of B-, Y-, and N-driven unique and common target genes. The identification of those most involved in transformation might reveal mechanisms and opportunities for therapy. Herein, transcription profiling of >60 murine HBs revealed a common set of 22 "BYN" genes similarly deregulated in all cases. Most were associated with multiple cancer hallmarks, and their expression often correlated with survival in HBs, hepatocellular carcinomas, and other cancers. Among the most down-regulated of these genes was Gas1, which encodes a glycosylphosphatidylinositol-linked outer membrane protein. The restoration of Gas1 expression impaired B + Y + N-driven HB tumor growth in vivo and in HB-derived immortalized BY and BYN cell lines in vitro in a manner that requires membrane anchoring of the protein via its glycosylphosphatidylinositol moiety, implicating Gas1 as a proximal mediator of HB pathogenesis and validating the BYN gene set as deserving of additional scrutiny in future studies.

Hepatoblastoma: Comprehensive Review With Recent Updates

Hepatoblastoma (HB), the most common primary malignant liver tumor of childhood, demonstrates remarkable histologic heterogeneity and can be classified into epithelial or mixed epithelial-mesenchymal subtypes. This review summarizes updates in histologic classification, molecular signatures, staging, and risk stratification of HB. The Children's Hepatic tumors International Collaboration represents an international effort to standardize the study of rare pediatric liver tumors; emphasis continues to remain on improving risk stratification by a combination of clinical, histologic, and molecular features to tailor treatment in a bid to reduce toxicity while maintaining or improving efficacy. Pure fetal HB is cured by complete resection without the need for adjuvant chemotherapy. Malignant rhabdoid tumors have been parsed out from small cell undifferentiated HBs by negative INI-1 staining on immunohistochemistry; these tumors require a distinct and more aggressive chemotherapeutic regimen. The significance of recently characterized "blastema" component in HB remains to be elucidated. Hepatocellular neoplasm, not otherwise specified, is a provisional diagnostic category for tumors exhibiting either intermediate or a combination of both HB and hepatocellular carcinoma histologic features. The Children's Hepatic tumors International Collaboration risk stratification algorithm includes age as an important discriminator of risk, in addition to AFP, metastasis, and PreTreatment EXTent of disease stage and its annotations.

Relevance of transportome among the mechanisms of chemoresistance in hepatoblastoma

Approximately 20 % of hepatoblastomas (HBs) exhibit a poor response to conventional chemotherapy due to mechanisms of chemoresistance (MOCs), such as reduced intracellular drug accumulation. This study evaluated the role of transportome in the multidrug resistance (MDR) of HB. Paired HB and adjacent liver tissue samples (n = 19) and HB-derived cell lines (HepG2, HuH6) were analyzed for their resistome characterization at mRNA (RT-qPCR, Taqman Low-Density Array, sequencing) and protein (western blot, immunohistochemistry, immunofluorescence) levels. Cell viability (MTT test) proliferation and migration (holographic microscopy) were determined. The impact of short-term (72 h) and long-term (>10 months) exposure of HB cells to cisplatin or doxorubicin on the transportome was investigated. Solute carrier (SLC) family of transporters showed minor relevance in HB MDR, while drug export pumps, particularly MRP2, were associated with poor response to chemotherapy. Exposure of HB cells to doxorubicin or cisplatin up-regulated MDR1, MRP1 and MRP2. In cells with induced persistent chemoresistance, the expression of genes involved in other MOCs, and epigenetic machinery was altered. Chemoresistant cells showed cross-resistance to several anticancer drugs but maintained sensitivity to cabozantinib. In conclusion, drug export pumps, but not SLC uptake transporters, are key contributors to HB chemoresistance. Cabozantinib emerges as a potential therapeutic option for HBs resistant to conventional chemotherapy.

Image-Guided Biopsy for the Diagnosis and Molecular Profiling of Hepatoblastoma

INTRODUCTION

Studies on the use of image-guided percutaneous biopsy for hepatoblastoma (HB), and recommendations put forth by the pediatric hepatic international tumor trial (PHITT), are limited. It is unknown if sufficient tissue can be obtained for trial enrollment as well as molecular profiling, which will likely play a key role in informing future treatment strategies.

METHODS AND MATERIALS

Patients with HB who underwent percutaneous biopsy at initial diagnosis in interventional radiology (IR) over a 12-year period at a single center were included. Patient demographics, pretreatment extent of disease (PRETEXT) stage, tumor size, and procedure details were collected. Pathology reports and tumor genomic analysis, when performed, were assessed for specimen adequacy. Post-procedure records were assessed for hemoperitoneum.

RESULTS

A total of 33 percutaneous biopsies were performed on 32 patients [17 female; median age 1.3 years (IQR: 0.7-2.5 years); median weight 10.5 kg (IQR: 7.4-12.7 kg)]. Most (n = 27) had a single liver lesion, and most (n = 18) were PRETEXT II. A total of 15 were positive for at least one annotation factor. Median longest tumor axis was 9.3 cm (IQR: 5.0-13.5 cm). A total of 16 patients had concurrent non-targeted liver biopsy, per PHITT recommendations. An 18-gauge instrument was most commonly used (n = 24, 73%) with a median of 8 cores (IQR: 6-12) obtained. There were no instances of hemoperitoneum. Tissue was adequate for histologic diagnosis in 97% (n = 32), with histologic subtyping obtained in 94% (30/32). When available (n = 29), comparison with the subsequent surgical resection specimen showed subtype concordance in 15 (52%) patients and minor variations secondary to sampling or treatment effect in 14 patients. Molecular profiling was completed on 21/21 specimens (100%), with 19/21 (90%) showing potentially clinically significant variants, most commonly in CTNNB1 (16/21).

CONCLUSION

In this single-center study, percutaneous biopsy resulted in no serious adverse events, a high rate of diagnosis, and successful subtyping and molecular characterization of HB.

Identification of MAD2L1 as a novel biomarker for hepatoblastoma through bioinformatics and machine learning approaches

Objective

This study aims to identify potential biomarkers for Hepatoblastoma (HB) using bioinformatics and machine learning, and to explore their underlying mechanisms of action.

Methods

We analyzed the datasets GSE131329 and GSE133039 to perform differential gene expression analysis. Single-sample gene set enrichment analysis (ssGSEA) and weighted gene co-expression network analysis (WGCNA) were utilized to identify gene modules linked to gene set activity. Protein-protein interaction (PPI) networks were constructed to identify hub genes, while random forest and support vector machine models were employed to screen for key diagnostic genes. Survival and immune infiltration analyses were conducted to assess the prognostic significance of these genes. Additionally, the expression levels, biological functions, and mechanisms of action of the selected genes were validated in HB cells through relevant experimental assays.

Results

We identified 1,377 and 1,216 differentially expressed genes in datasets GSE131329 and GSE133039, respectively. ssGSEA and WGCNA analyses identified 234 genes significantly linked to gene set activity. PPI analysis identified 20 core Hub genes. Machine learning highlighted three key diagnostic genes: CDK1, CCNA2, and MAD2L1. Studies have demonstrated that MAD2L1 is significantly overexpressed in HB and is associated with prognosis. WGCNA revealed that MAD2L1 is enriched in gene sets related to E2F_ TARGETS and G2M_CHECKPOINT. Experimental assays demonstrated that MAD2L1 knockdown significantly inhibits the proliferation, migration, and invasion of HB cell lines, and that MAD2L1 promotes cell cycle progression through the regulation of E2F.

Conclusion

Our study identifies MAD2L1 as a novel potential biomarker for HB, providing new strategies for early diagnosis and targeted therapy in HB.

Hepatoblastoma: From Molecular Mechanisms to Therapeutic Strategies

Hepatoblastoma (HB) is the most common malignant liver tumor in children under five years of age. Although globally rare, it accounts for a large proportion of liver cancer in children and has poor survival rates in high-risk and metastatic cases. This review discusses the molecular mechanisms, diagnostic methods, and therapeutic strategies of HB. Mutations in the CTNNB1 gene and the activation of the Wnt/β-catenin pathway are essential genetic factors. Furthermore, genetic syndromes like Beckwith-Wiedemann syndrome (BWS) and Familial Adenomatous Polyposis (FAP) considerably heighten the risk of associated conditions. Additionally, epigenetic mechanisms, such as DNA methylation and the influence of non-coding RNAs (ncRNAs), are pivotal drivers of tumor development. Diagnostics include serum biomarkers, immunohistochemistry (IHC), and imaging techniques. Standard treatments are chemotherapy, surgical resection, and liver transplantation (LT). Emerging therapies like immunotherapy and targeted treatments offer hope against chemotherapy resistance. Future research will prioritize personalized medicine, novel biomarkers, and molecular-targeted therapies to improve survival outcomes.

ACSL4 promotes the formation of the proliferative subtype in hepatoblastoma

Hepatoblastoma (HB) is the most common pediatric liver malignancy, with its significant heterogeneity complicating the identification of the most aggressive subtypes and the development of targeted therapies. In this study, we performed transcriptomic analysis of HB samples from the GEO database and identified three distinct molecular subtypes with varying prognostic outcomes. Among them, the proliferative subtype, characterized by enhanced proliferative capacity, poor prognosis, and an immunosuppressive tumor microenvironment, was particularly notable. ACSL4 emerged as a critical biomarker of this proliferative subtype, driving HB cell proliferation both in vitro and in vivo. Furthermore, pharmacological inhibition of ACSL4 using abemaciclib significantly suppressed tumor growth in xenograft models. Mechanistically, ACSL4 was found to promote cell proliferation by downregulating the interferon response signaling pathway which may implicate contribution to immunosuppression in the tumor. These findings underscore the pivotal role of ACSL4 in HB progression and highlight its potential as a therapeutic target for aggressive HB subtypes.

Multiomic analysis uncovers a continuous spectrum of differentiation and Wnt-MDK-driven immune evasion in hepatoblastoma

BACKGROUND & AIMS

Hepatoblastoma is the most common pediatric cancer of the liver, with the majority of cases displaying activating mutations in the Wnt/β-catenin pathway. Understanding the complex milieu of the tumor microenvironment has resulted in promising new therapies for adult cancers, but similar approaches in pediatric cancers are still lacking. We aimed to provide a comprehensive analysis of the tumor microenvironment of hepatoblastoma, unveiling its spatial architecture and key signaling mechanisms.

METHODS

Single-cell/-nucleus RNA-sequencing (RNA-seq) (n = 15), spatial transcriptomics (n = 22), and multiplex immunofluorescence stainings (n = 7) of treated, untreated, and metastasized pediatric hepatoblastomas were performed. An RNA-seq validation cohort (n = 110) including hepatoblastoma, non-tumor and fetal liver samples and single-cell RNA-seq data of healthy immune cells were used for further analysis. Western blotting and RNA-seq of hepatoblastoma and macrophage cell lines were conducted for experimental validation.

RESULTS

Of four identified transcriptional tumor programs, "Developmental" and "Metabolic" reflected different hepatic differentiation stages, while "Cycling" was enriched in undifferentiated cells and relapsed samples, and "Intermediate" displayed high activity in samples from patients with poor outcomes. We discovered an increased ratio of anti-to pro-inflammatory immune cells and evidence of immune exclusion from tumor areas. Wnt-responsive upregulation of the immunomodulator midkine in hepatoblastoma cells was associated with a change in macrophage phenotype, which could be partially reversed through midkine inhibition.

CONCLUSIONS

Hepatoblastoma cells exist along a continuous spectrum of hepatic differentiation and inhabit an altered immune environment. Wnt signaling augments midkine expression, which appears to be involved in shaping the immune environment by modifying macrophages to enable immune evasion, thereby providing a potential therapeutic target.

IMPACT AND IMPLICATIONS

Despite hepatoblastoma being the most common pediatric liver cancer, there has been a critical knowledge gap in understanding how the tumor microenvironment and immune landscape contribute to disease progression. Our novel findings, revealing a continuous spectrum of tumor differentiation states and Wnt-MDK-driven immune evasion, are significant for pediatric oncology clinicians and researchers, improving our functional understanding of the immune environment of hepatoblastoma. The identification of midkine as a tumor-specific immunomodulator suggests a potential for developing new targeted therapies, though further mechanistic and practical validation would be needed to realize clinical translation of these findings.

Epigenetic regulation and its therapeutic potential in hepatitis B virus covalently closed circular DNA

Human hepatitis B virus (HBV) infection is the major cause of acute and chronic hepatitis B, liver cirrhosis, and hepatocellular carcinoma. Although the application of prophylactic vaccination programs has successfully prevented the trend of increasing HBV infection prevalence, the number of HBV-infected people remains very high. Approved therapeutic management efficiently suppresses viral replication; however, HBV infection is rarely completely resolved. The major reason for therapeutic failure is the persistence of covalently closed circular DNA (cccDNA), which forms viral minichromosomes by combining with histone and nonhistone proteins in the nucleus. Increasing evidence indicates that chromatin-modifying enzymes, viral proteins, and noncoding RNAs are essential for modulating the function of cccDNA. Therefore, a deeper understanding of the regulatory mechanism underlying cccDNA transcription will contribute to the development of a cure for chronic hepatitis B. This review summarizes the current knowledge of cccDNA biology, the regulatory mechanisms underlying cccDNA transcription, and novel anti-HBV approaches for eliminating cccDNA transcription.

"Update on pediatric primary liver tumors"

Liver masses are common in children, however primary malignant neoplasms are rare, representing only 1% of all pediatric cancers. Hepatocellular neoplasms are the most common primary liver malignancies and hepatoblastoma (HB) is the most frequently diagnosed. The incidence of HB, which is increasing, is approximately of 2 cases per million in the United States, followed by hepatocellular carcinoma (HCC). Pediatric primary liver tumors of mesenchymal origin are less common, except for benign vascular tumors (hemangiomas). Malignant mesenchymal neoplasms represent approximately 10-15% of all, the most common being embryonal sarcoma and malignant rhabdoid tumor. Malignant vascular tumors are rare, but epithelioid hemangioendothelioma (EHE) and angiosarcoma can be seen in children. The development and adoption of consensus diagnostic, therapeutic and risk-stratifying approaches for pediatric patients with malignant liver tumors has been historically challenged by their rarity and by their diverse clinical and histological appearance. On-going collaborative efforts of international consortia including the Children's Oncology Group (COG) in North America, the German Society of Paediatric Oncology and Haematology (GPOH), the Societe Internationale d' Oncologie Pediatrique Liver Tumor Study Group (SIOPEL) in Europe and the Japanese Liver Tumor group (JPLT), have made significant contributions to understanding the clinical and histopathological features, as well as the underlying biology of pediatric liver tumors, in particular HB. A new classification of pediatric liver tumors drafted at the international consensus meeting held in Los Angeles, has been incorporated in the recent WHO classification and is currently used by the PHITT (Paediatric Hepatic Malignancy International Tumour Trial) and other therapeutic protocols. This manuscript provides an overview of salient diagnostic features and updates in classification and molecular characterization for the most common pediatric primary liver neoplasms. It also includes a brief overview of other less common but relevant tumors, which should be considered in the differential diagnosis.

Liver cancer multiomics reveals diverse protein kinase A disruptions convergently produce fibrolamellar hepatocellular carcinoma

Fibrolamellar Hepatocellular Carcinoma (FLC) is a rare liver cancer characterized by a fusion oncokinase of the genes DNAJB1 and PRKACA, the catalytic subunit of protein kinase A (PKA). A few FLC-like tumors have been reported showing other alterations involving PKA. To better understand FLC pathogenesis and the relationships among FLC, FLC-like, and other liver tumors, we performed a massive multi-omics analysis. RNA-seq data of 1412 liver tumors from FLC, hepatocellular carcinoma, hepatoblastoma and intrahepatic cholangiocarcinoma are analyzed, obtaining transcriptomic signatures unrestricted by experimental processing methods. These signatures reveal which dysregulations are unique to specific tumors and which are common to all liver cancers. Moreover, the transcriptomic FLC signature identifies a unifying phenotype for all FLC tumors regardless of how PKA was activated. We study this signature at multi-omics and single-cell levels in the first spatial transcriptomic characterization of FLC, identifying the contribution of tumor, normal, stromal, and infiltrating immune cells. Additionally, we study FLC metastases, finding small differences from the primary tumors.

Targeted inhibition of CHKα and mTOR in models of pancreatic ductal adenocarcinoma: A novel regimen for metastasis

Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic malignancy for which there are currently no effective anti-metastatic therapies. Herein, we employed single-cell RNA sequencing and metabolomics analysis to demonstrate that metastatic cells highly express focal adhesion kinase (FAK), which promotes metastasis by remodeling choline kinase α (CHKα)-dependent choline metabolism. We designed a novel CHKα inhibitor, CHKI-03, and verified its efficacy in inhibiting metastasis in multiple preclinical models. Classical and newly synthesized small-molecule inhibitors have previously been used to assess the therapeutic potential of targeting mTOR and CHKα in various animal models. Mechanistically, FAK activated mTOR and its downstream HIF-1α, thereby elevating CHKα expression and promoting the proliferation, migration, and invasion of PDAC cells, as well as tumor growth and metastasis. Consistently, high expression levels of both FAK and CHKα are correlated with poor prognosis in patients with PDAC. Notably, CHK1-03 inhibited CHKα expression and also suppressed mTORC1 phosphorylation, disrupting the mTORC1-CHKα positive feedback loop. In addition, the combination of CHKI-03 and the mTORC1 inhibitor rapamycin synergistically inhibited tumor growth and metastasis in PDX models. The combination of CHKI-03 and rapamycin demonstrates considerable therapeutic efficacy in PDO models resistant to gemcitabine. Our findings reveal a pivotal mechanism underlying PDAC metastasis regulated by mTORC1-CHKα loop-dependent choline metabolism reprogramming, highlighting the therapeutic potential of this novel regimen for treating PDAC metastasis.

A developmental biliary lineage program cooperates with Wnt activation to promote cell proliferation in hepatoblastoma

Cancers evolve not only through the acquisition and clonal transmission of somatic mutations but also by epigenetic mechanisms that modify cell phenotype. Here, we use histology-guided and spatial transcriptomics to characterize hepatoblastoma, a childhood liver cancer that exhibits significant histologic and proliferative heterogeneity despite clonal activating mutations in the Wnt/β-catenin pathway. Highly proliferative regions with embryonal histology show high expression of Wnt target genes, the embryonic biliary transcription factor SOX4, and striking focal expression of the growth factor FGF19. In patient-derived tumoroids with constitutive Wnt activation, FGF19 is a required growth signal for FGF19-negative cells. Indeed, some tumoroids contain subsets of cells that endogenously express FGF19, downstream of Wnt/β-catenin and SOX4. Thus, the embryonic biliary lineage program cooperates with stabilized nuclear β-catenin, inducing FGF19 as a paracrine growth signal that promotes tumor cell proliferation, together with active Wnt signaling. In this pediatric cancer presumed to originate from a multipotent hepatobiliary progenitor, lineage-driven heterogeneity results in a functional growth advantage, a non-genetic mechanism whereby developmental lineage programs influence tumor evolution.

Divergent WNT signaling and drug sensitivity profiles within hepatoblastoma tumors and organoids

Hepatoblastoma, the most prevalent pediatric liver cancer, almost always carries a WNT-activating CTNNB1 mutation, yet exhibits notable molecular heterogeneity. To characterize this heterogeneity and identify novel targeted therapies, we perform comprehensive analysis of hepatoblastomas and tumor-derived organoids using single-cell RNA-seq/ATAC-seq, spatial transcriptomics, and high-throughput drug profiling. We identify two distinct tumor epithelial signatures: hepatic 'fetal' and WNT-high 'embryonal', displaying divergent WNT signaling patterns. The fetal group is enriched for liver-specific WNT targets, while the embryonal group is enriched in canonical WNT target genes. Gene regulatory network analysis reveals enrichment of regulons related to hepatic functions such as bile acid, lipid and xenobiotic metabolism in the fetal subtype but not in the embryonal subtype. In addition, the dichotomous expression pattern of the transcription factors HNF4A and LEF1 allows for a clear distinction between the fetal and embryonal tumor cells. We also perform high-throughput drug screening using patient-derived tumor organoids and identify sensitivity to HDAC inhibitors. Intriguingly, embryonal and fetal tumor organoids are sensitive to FGFR and EGFR inhibitors, respectively, indicating a dependency on EGF/FGF signaling in hepatoblastoma tumorigenesis. In summary, our data uncover the molecular and drug sensitivity landscapes of hepatoblastoma and pave the way for the development of targeted therapies.

Integrative analysis based on ATAC-seq and RNA-seq reveals a novel oncogene PRPF3 in hepatocellular carcinoma

BACKGROUND

Assay of Transposase Accessible Chromatin Sequencing (ATAC-seq) is a high-throughput sequencing technique that detects open chromatin regions across the genome. These regions are critical in facilitating transcription factor binding and subsequent gene expression. Herein, we utilized ATAC-seq to identify key molecular targets regulating the development and progression of hepatocellular carcinoma (HCC) and elucidate the underlying mechanisms.

METHODS

We first compared chromatin accessibility profiles between HCC and normal tissues. Subsequently, RNA-seq data was employed to identify differentially expressed genes (DEGs). Integrating ATAC-seq and RNA-seq data allowed the identification of transcription factors and their putative target genes associated with differentially accessible regions (DARs). Finally, functional experiments were conducted to investigate the effects of the identified regulatory factors and corresponding targets on HCC cell proliferation and migration.

RESULTS

Enrichment analysis of DARs between HCC and adjacent normal tissues revealed distinct signaling pathways and regulatory factors. Upregulated DARs in HCC were enriched in genes related to the MAPK and FoxO signaling pathways and associated with transcription factor families like ETS and AP-1. Conversely, downregulated DARs were associated with the TGF-β, cAMP, and p53 signaling pathways and the CTCF family. Integration of the datasets revealed a positive correlation between specific DARs and DEGs. Notably, PRPF3 emerged as a gene associated with DARs in HCC, and functional assays demonstrated its ability to promote HCC cell proliferation and migration. To the best of our knowledge, this is the first report highlighting the oncogenic role of PRPF3 in HCC. Furthermore, ZNF93 expression positively correlated with PRPF3, and ChIP-seq data indicated its potential role as a transcription factor regulating PRPF3 by binding to its promoter region.

CONCLUSION

This study provides a comprehensive analysis of the epigenetic landscape in HCC, encompassing both chromatin accessibility and the transcriptome. Our findings reveal that ZNF93 promotes the proliferation and motility of HCC cells through transcriptional regulation of a novel oncogene, PRPF3.

Machine learning approach to predict blood-secretory proteins and potential biomarkers for liver cancer using omics data

Identifying non-invasive blood-based biomarkers is crucial for early detection and monitoring of liver cancer (LC), thereby improving patient outcomes. This study leveraged computational approaches to predict potential blood-based biomarkers for LC. Machine learning (ML) models were developed using selected features from blood-secretory proteins collected from the curated databases. The logistic regression (LR) model demonstrated the optimal performance. Transcriptome analysis across 7 LC cohorts revealed 231 common differentially expressed genes (DEGs). The encoded proteins of these DEGs were compared with the ML dataset, revealing 29 proteins overlapping with the blood-secretory dataset. The LR model also predicted 29 additional proteins as blood-secretory with the remaining protein-coding genes. As a result, 58 potential blood-secretory proteins were obtained. Among the top 20 genes, 13 common hub genes were identified. Further, area under the receiver operating characteristic curve (ROC AUC) analysis was performed to assess the genes as potential diagnostic blood biomarkers. Six genes, ESM1, FCN2, MDK, GPC3, CTHRC1 and COL6A6, exhibited an AUC value higher than 0.85 and were predicted as blood-secretory. This study highlights the potential of an integrative computational approach for discovering non-invasive blood-based biomarkers in LC, facilitating for further validation and clinical translation. SIGNIFICANCE: Liver cancer is one of the leading causes of premature death worldwide, with its prevalence and mortality rates projected to increase. Although current diagnostic methods are highly sensitive, they are invasive and unsuitable for repeated testing. Blood biomarkers offer a promising non-invasive alternative, but their wide dynamic range of protein concentration poses experimental challenges. Therefore, utilizing available omics data to develop a diagnostic model could provide a potential solution for accurate diagnosis. This study developed a computational method integrating machine learning and bioinformatics analysis to identify potential blood biomarkers. As a result, ESM1, FCN2, MDK, GPC3, CTHRC1 and COL6A6 biomarkers were identified, holding significant promise for improving diagnosis and understanding of liver cancer. The integrated method can be applied to other cancers, offering a possible solution for early detection and improved patient outcomes.

Making sense of artificial intelligence and large language models-including ChatGPT-in pediatric hematology/oncology

ChatGPT and other artificial intelligence (AI) systems have captivated the attention of healthcare providers and researchers for their potential to improve care processes and outcomes. While these technologies hold promise to automate processes, increase efficiency, and reduce cognitive burden, their use also carries risks. In this commentary, we review basic concepts of AI, outline some of the capabilities and limitations of currently available tools, discuss current and future applications in pediatric hematology/oncology, and provide an evaluation and implementation framework that can be used by pediatric hematologist/oncologists considering the use of AI in clinical practice.

Worldwide burden of liver cancer across childhood and adolescence, 2000-2021: a systematic analysis of the Global Burden of Disease Study 2021

Background

Liver cancer is a significant contributor to the global disease burden, of which hepatoblastomas are the most common liver tumors in children, with 90% of cases occurring within the first 5 years of life. It is important for pediatricians and subspecialists in pediatric gastroenterology and hepatology to have knowledge of the epidemiology and incidence trends of pediatric hepatic cancer, despite its rarity. In the present study, we first provide estimates of the incidence and mortality burden of hepatoblastoma and liver cancer from 2000 to 2021 in the childhood and adolescence.

Methods

Liver cancer burden and its attributable risk factors were estimated using data from the Global Burden of Disease Study (GBD) 2021. Percentage change was estimated to show the trend of liver cancer estimates from 2000 to 2021. The age-standardized rate (ASR) and estimated annual percentage change (EAPC) were utilized for measuring hepatoblastomas incidence and deaths rate trends. In accordance with the GBD framework, 95% uncertainty intervals (UIs) for all estimates by averaging the data from 1000 draws, with the lower and upper bounds of the 95% UIs.

Findings

Globally, from 2000 to 2021 in the age 5-19 years group, the incidence cases and deaths cases due to liver cancer decreased from 2449.2 (95% UI: 2235.9-2689.8) to 1692.9 (95% UI: 1482.0-1992.5) and 2248.5 (95% UI: 2053.7-2474.9) to 1516.6 (95% UI: 1322.1-1797.9), respectively. Meanwhile, from 2000 to 2021 in the age 20-24 years group, the incidence cases and deaths cases due to liver cancer decreased from 1453.5 (95% UI: 1327.8-1609.4) to 1285.1 (95% UI: 1159.2-1447.2) and 1432.3 (95% UI: 1307.6-1585.7) to 1195.5 (95% UI: 1066.1-1355.2), respectively. In addition, the prevalence of liver cancer decreased from 41.9% (95% UI: 18.7%-64.7%) to 26.4% (95% UI: 14.2%-39.1%) in the age 5-19 years group, and 46.6% (95% UI: 42.8%-51.5%) to 36.5% (95% UI: 33.1%-40.9%) in the age 20-24 years. From 2000 to 2021, in the age group of 5-19 years, the proportion of liver cancer incidence due to hepatitis B has decreased from 42.2% to 37.9%, while the proportion due to hepatitis C has increased from 1.1% to 1.6%. Additionally, there has been an increase in the proportion of NASH-induced liver cancer incidence from 5.2% to 9.4%, and alcohol use induced liver cancer incidence has also increased from 0.5% to 0.7% over the same period. Globally, from 2000 to 2021, the incidence cases and deaths cases due to hepatoblastoma decreased from 6131.8 (95% UI: 5234.8-6961.9) to 4045.6 (95% UI: 3250-4995.8) and 4059.2 (95% UI: 3494.5-4621.2) to 2416 (95% UI: 1940.2-3022.5), respectively. There was some variation in age-related sex-specific patterns, the highest number of hepatoblastoma incidence cases occurred in children between 2 and 4 years old and females in the age range of 12 months to 9 years had a higher number of new cases. Importantly, the incidence of hepatoblastoma was started to increase sharply after the age of 1 month.

Interpretation

The results of the present study are significant for liver health policy and practice in childhood and adolescence. Differentiated intervention and outreach strategies based on age and gender would be necessary to reduce the impact of liver cancer. Early screening and interventions for hepatoblastoma is important especially in the population of under 9 years old.

Funding

This study was supported by the National Key R&D Program of China (grant numbers 2023YFC2307000), National Natural Science Foundation of China [grant numbers 82170571 and 81974068], China Postdoctoral Science Foundation (grant numbers 2023M741283).

LINC01370 suppresses hepatocellular carcinoma proliferation and metastasis by regulating the PI3K/AKT pathway

BACKGROUND

Hepatocellular carcinoma (HCC) poses a serious threat to human health worldwide. lncRNA dysregulation is frequently observed in various cancers, including HCC. However, the function of LINC01370 in HCC progression and its underlying mechanisms remain unclear.

METHODS

LINC01370 expression in HCC tissues with cells was analyzed by applying the GEO and GEPIA databases and qRT-PCR. CCK-8 and Transwell assays were used to assess HCC cell proliferation, migration, and invasion. The PI3K, AKT, with p-AKT protein expression were analyzed by western blotting.

RESULTS

Gene Expression Omnibus (GEO) and Gene Expression Profiling Interactive Analysis (GEPIA) showed that LINC01370 expression was significantly lower in HCC tissues than in normal tissues. LINC01370 overexpression markedly repressed HepG2 SMMC-7721 cells proliferation, migration, and invasion. To understand the downstream mechanism of LINC01370 regulation, we further analyzed the genes co-expressed with LINC01370 in GSE136247 and GSE132037 and then performed KEGG analysis. The PA pathway was found to be a downstream pathway regulated by LINC01370 in GSE136247 and GSE132037 via gene co-expression and KEGG analysis. Furthermore, PI3K and p-AKT protein levels decreased after LINC01370 overexpression. Importantly, rescue experiments showed that activation of the PI3K/AKT pathway disrupted the repressive effect of LINC01370 overexpression on the proliferation, migration, and invasion of HepG2 of SMMC-7721 cells.

CONCLUSIONS

This study verified that LINC01370 suppresses HCC proliferation with metastasis by regulating the PI3K/AKT pathway.

Computational drug prediction in hepatoblastoma by integrating pan-cancer transcriptomics with pharmacological response

BACKGROUND AND AIMS

Hepatoblastoma (HB) is the predominant form of pediatric liver cancer, though it remains exceptionally rare. While treatment outcomes for children with HB have improved, patients with advanced tumors face limited therapeutic choices. Additionally, survivors often suffer from long-term adverse effects due to treatment, including ototoxicity, cardiotoxicity, delayed growth, and secondary tumors. Consequently, there is a pressing need to identify new and effective therapeutic strategies for patients with HB. Computational methods to predict drug sensitivity from a tumor's transcriptome have been successfully applied for some common adult malignancies, but specific efforts in pediatric cancers are lacking because of the paucity of data.

APPROACH AND RESULTS

In this study, we used DrugSense to assess drug efficacy in patients with HB, particularly those with the aggressive C2 subtype associated with poor clinical outcomes. Our method relied on publicly available collections of pan-cancer transcriptional profiles and drug responses across 36 tumor types and 495 compounds. The drugs predicted to be most effective were experimentally validated using patient-derived xenograft models of HB grown in vitro and in vivo. We thus identified 2 cyclin-dependent kinase 9 inhibitors, alvocidib and dinaciclib as potent HB growth inhibitors for the high-risk C2 molecular subtype. We also found that in a cohort of 46 patients with HB, high cyclin-dependent kinase 9 tumor expression was significantly associated with poor prognosis.

CONCLUSIONS

Our work proves the usefulness of computational methods trained on pan-cancer data sets to reposition drugs in rare pediatric cancers such as HB, and to help clinicians in choosing the best treatment options for their patients.

N6-methyladenosine modified lncRNAs signature for stratification of biochemical recurrence in prostate cancer

Nonmutational epigenetic reprogramming is a crucial mechanism contributing to the pronounced heterogeneity of prostate cancer (PCa). Among these mechanisms, N6-methyladenosine (m6A)-modified long non-coding RNAs (lncRNAs) have emerged as key players. However, the precise roles of m6A-modified lncRNAs in PCa remain to be elucidated. In this study, methylated RNA immunoprecipitation sequencing (MeRIP-seq) was conducted on primary and metastatic PCa samples, leading to the identification of 21 lncRNAs exhibiting differential methylation and expression patterns. We further established a PCa prognostic signature, named m6A-modified lncRNA score (mLs), based on 9 differential methylated lncRNAs in 4 multicenter cohorts. The high mLs score cohort exhibited a tendency for earlier biochemical recurrence (BCR) compared to the low mLs score cohort. Remarkably, the predictive performance of the mLs score surpassed that of five previously reported lncRNA-based signatures. Functional enrichment analysis underscored a negative correlation between the mLs score and lipid metabolism. Additionally, through MeRIP-qPCR, we pinpointed a hub gene, MIR210HG, which was validated through in vitro and in vivo experiments. These findings collectively illuminate the landscape of m6A-methylated lncRNAs in PCa tissue via MeRIP-seq and harness this information to prognosticate PCa outcomes using the mLs score. Furthermore, our study validates, both experimentally and mechanistically, the facilitative role of MIR210HG in driving PCa progression.

Inhibition of Histone Deacetylase Activity Increases Cisplatin Efficacy to Eliminate Metastatic Cells in Pediatric Liver Cancers

The pediatric liver cancers, hepatoblastoma and hepatocellular carcinoma, are dangerous cancers which often spread to the lungs. Although treatments with cisplatin significantly improve outcomes, cisplatin may not eliminate metastasis-initiating cells. Our group has recently shown that the metastatic microenvironments of hepatoblastoma contain Cancer Associated Fibroblasts (CAFs) and neuron-like cells, which initiate cancer spread from liver to lungs. In this study, we found that these cells express high levels of HDAC1; therefore, we examined if histone deacetylase inhibition improves cisplatin anti-proliferative effects and reduces the formation of tumor clusters in pediatric liver cancer metastatic microenvironments.

METHODS

New cell lines were generated from primary hepatoblastoma liver tumors (hbl) and lung metastases (LM) of HBL patients. In addition, cell lines were generated from hepatocellular neoplasm, not otherwise specified (HCN-NOS) tumor samples, and hcc cell lines. Hbl, LM and hcc cells were treated with cisplatin, SAHA or in combination. The effect of these drugs on the number of cells, formation of tumor clusters and HDAC1-Sp5-p21 axis were examined.

RESULTS

Both HBL and HCC tissue specimens have increased HDAC1-Sp5 pathway activation, recapitulated in cell lines generated from the tumors. HDAC inhibition with vorinostat (SAHA) increases cisplatin efficacy to eliminate CAFs in hbl and in hcc cell lines. Although the neuron-like cells survive the combined treatments, proliferation was inhibited. Notably, combining SAHA with cisplatin overcame cisplatin resistance in an LM cell line from an aggressive case with multiple metastases. Underlying mechanisms of this enhanced inhibition include suppression of the HDAC1-Sp5 pathway and elevation of an inhibitor of proliferation p21. Similar findings were found with gemcitabine treatments suggesting that elimination of proliferative CAFs cells is a key event in the inhibition of mitotic microenvironment.

CONCLUSIONS

Our studies demonstrate the synergistic benefits of HDAC inhibition and cisplatin to eliminate metastasis-initiating cells in pediatric liver cancers.

Focal adhesion kinase and its epigenetic interactors as diagnostic and therapeutic hints for pediatric hepatoblastoma

Background

Hepatoblastoma (HB) is the most common pediatric hepatic malignancy. Despite the progress in HB treatment, investigating HB pathomechanisms to optimize stratification and therapies remains a focal point to improve the outcome for high-risk patients.

Methods

Here, we pointed to explore the impact of these mechanisms in HB. An observational study was performed on liver samples from a cohort of 17 patients with a diagnosis of HB and two normal liver samples. The in vitro experiments were executed on the Huh6 human HB cell line treated with the FAK inhibitor TAE226.

Results

Our results highlight a significant up-regulation of mRNA and protein expression of FAK in livers from HB with respect to normal livers. The increased protein expression of total and Tyr397 phosphorylated FAK (pTyr397FAK) was significantly correlated with the expression of some epigenetic regulators of histone H3 methylation and acetylation. Of note, the expression of pTyr397FAK, N-methyltransferase enzyme (EZH2) and tri-methylation of the H3K27 residue correlated with tumor size and alpha-fetoprotein (AFP) levels. Finally, TAE226 caused a significant reduction of pTyr397FAK, epigenetic regulators, AFP, EPCAM, OCT4, and SOX2, in association with anti-proliferative and pro-apoptotic effects on HB cells.

Conclusion

Our results suggest a role of FAK in HB that requires further investigations mainly focused on the exploration of its effective diagnostic and therapeutic translatability.

Immunosuppression in liver transplant oncology: position paper of the Italian Board of Experts in Liver Transplantation (I-BELT)

Liver transplant oncology (TO) represents an area of increasing clinical and scientific interest including a heterogeneous group of clinical-pathological settings. Immunosuppressive management after LT is a key factor relevantly impacting result. However, disease-related guidance is still lacking, and many open questions remain in the field. Based on such a substantial lack of solid evidences, the Italian Board of Experts in Liver Transplantation (I-BELT) (a working group including representatives of all national transplant centers), unprecedently promoted a methodologically sound consensus conference on the topic, based on the GRADE approach. The group final recommendations are herein presented and commented. The 18 PICOs and Statements and their levels of evidence and grades of recommendation are reported and grouped into seven areas: (1) risk stratification by histopathological and bio-molecular parameters and role of mTORi post-LT; (2) steroids and HCC recurrence; (3) management of immunosuppression when HCC recurs after LT; (4) mTORi monotherapy; (5) machine perfusion and HCC recurrence after LT; (6) physiopathology of tumor-infiltrating lymphocytes and immunosuppression, the role of inflammation; (7) immunotherapy in liver transplanted patients. The interest in mammalian targets of rapamycin inhibitors (mTORi), for steroid avoidance and the need for a reduction to CNI exposure emerged from the consensus process. A selected list of unmet needs prompting further investigations have also been developed. The so far heterogeneous and granular approach to immunosuppression in oncologic patients deserves greater efforts for a more standardized therapeutic response to the different clinical scenarios. This consensus process makes a first unprecedented step in this direction, to be developed on a larger scale.

First Transcriptome Analysis of Hepatoblastoma in Brazil: Unraveling the Pivotal Role of Noncoding RNAs and Metabolic Pathways

Hepatoblastoma stands as the most prevalent liver cancer in the pediatric population. Characterized by a low mutational burden, chromosomal and epigenetic alterations are key drivers of its tumorigenesis. Transcriptome analysis is a powerful tool for unraveling the molecular intricacies of hepatoblastoma, shedding light on the effects of genetic and epigenetic changes on gene expression. In this study conducted in Brazilian patients, an in-depth whole transcriptome analysis was performed on 14 primary hepatoblastomas, compared to control liver tissues. The analysis unveiled 1,492 differentially expressed genes (1,031 upregulated and 461 downregulated), including 920 protein-coding genes (62%). Upregulated biological processes were linked to cell differentiation, signaling, morphogenesis, and development, involving known hepatoblastoma-associated genes (DLK1, MEG3, HDAC2, TET1, HMGA2, DKK1, DKK4), alongside with novel findings (GYNG4, CDH3, and TNFRSF19). Downregulated processes predominantly centered around oxidation and metabolism, affecting amines, nicotinamides, and lipids, featuring novel discoveries like the repression of SYT7, TTC36, THRSP, CCND1, GCK and CAMK2B. Two genes, which displayed a concordant pattern of DNA methylation alteration in their promoter regions and dysregulation in the transcriptome, were further validated by RT-qPCR: the upregulated TNFRSF19, a key gene in the embryonic development, and the repressed THRSP, connected to lipid metabolism. Furthermore, based on protein-protein interaction analysis, we identified genes holding central positions in the network, such as HDAC2, CCND1, GCK, and CAMK2B, among others, that emerged as prime candidates warranting functional validation in future studies. Notably, a significant dysregulation of non-coding RNAs (ncRNAs), predominantly upregulated transcripts, was observed, with 42% of the top 50 highly expressed genes being ncRNAs. An integrative miRNA-mRNA analysis revealed crucial biological processes associated with metabolism, oxidation reactions of lipids and carbohydrates, and methylation-dependent chromatin silencing. In particular, four upregulated miRNAs (miR-186, miR-214, miR-377, and miR-494) played a pivotal role in the network, potentially targeting multiple protein-coding transcripts, including CCND1 and CAMK2B. In summary, our transcriptome analysis highlighted disrupted embryonic development as well as metabolic pathways, particularly those involving lipids, emphasizing the emerging role of ncRNAs as epigenetic regulators in hepatoblastomas. These findings provide insights into the complexity of the hepatoblastoma transcriptome and identify potential targets for future therapeutic interventions.

Single-cell multiomics reveals the interplay of clonal evolution and cellular plasticity in hepatoblastoma

Hepatoblastomas (HB) display heterogeneous cellular phenotypes that influence the clinical outcome, but the underlying mechanisms are poorly understood. Here, we use a single-cell multiomic strategy to unravel the molecular determinants of this plasticity. We identify a continuum of HB cell states between hepatocytic (scH), liver progenitor (scLP) and mesenchymal (scM) differentiation poles, with an intermediate scH/LP population bordering scLP and scH areas in spatial transcriptomics. Chromatin accessibility landscapes reveal the gene regulatory networks of each differentiation pole, and the sequence of transcription factor activations underlying cell state transitions. Single-cell mapping of somatic alterations reveals the clonal architecture of each tumor, showing that each genetic subclone displays its own range of cellular plasticity across differentiation states. The most scLP subclones, overexpressing stem cell and DNA repair genes, proliferate faster after neo-adjuvant chemotherapy. These results highlight how the interplay of clonal evolution and epigenetic plasticity shapes the potential of HB subclones to respond to chemotherapy.

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.

Precision Oncology in Pediatric Cancer Surgery

Pediatric precision oncology has provided a greater understanding of the wide range of molecular alterations in difficult-to-treat or rare tumors with the aims of increasing survival as well as decreasing toxicity and morbidity from current cytotoxic therapies. In this article, the authors discuss the current state of pediatric precision oncology which has increased access to novel targeted therapies while also providing a framework for clinical implementation in this unique population. The authors evaluate the targetable mutations currently under investigation-with a focus on pediatric solid tumors-and discuss the key surgical implications associated with novel targeted therapies.

A TGF-β-dominant chemoresistant phenotype of hepatoblastoma associated with aflatoxin exposure in children

BACKGROUND AND AIMS

Hepatoblastoma (HB) is the most common liver cancer in children, posing a serious threat to children's health. Chemoresistance is the leading cause of mortality in patients with HB. A more explicit definition of the features of chemotherapy resistance in HB represents a fundamental urgent need.

APPROACH AND RESULTS

We performed an integrative analysis including single-cell RNA sequencing, whole-exome sequencing, and bulk RNA sequencing in 180 HB samples, to reveal genomic features, transcriptomic profiles, and the immune microenvironment of HB. Multicolor immunohistochemistry staining and in vitro experiments were performed for validation. Here, we reported four HB transcriptional subtypes primarily defined by differential expression of transcription factors. Among them, the S2A subtype, characterized by strong expression of progenitor ( MYCN , MIXL1 ) and mesenchymal transcription factors ( TWIST1 , TBX5 ), was defined as a new chemoresistant subtype. The S2A subtype showed increased TGF-β cancer-associated fibroblast and an immunosuppressive microenvironment induced by the upregulated TGF-β of HB. Interestingly, the S2A subtype enriched SBS24 signature and significantly higher serum aflatoxin B1-albumin (AFB1-ALB) level in comparison with other subtypes. Functional assays indicated that aflatoxin promotes HB to upregulate TGF-β. Furthermore, clinical prognostic analysis showed that serum AFB1-ALB is a potential indicator of HB chemoresistance and prognosis.

CONCLUSIONS

Our studies offer new insights into the relationship between aflatoxin and HB chemoresistance and provide important implications for its diagnosis and treatment.

Prognostic and predictive biomarkers in paediatric solid tumours

Characterisation of histological, immunohistochemical and molecular prognostic and predictive biomarkers has contributed significantly to precision medicine and better outcomes in the management of paediatric solid tumours. Prognostic biomarkers allow predictions to be made regarding a tumour's aggressiveness and clinical course, whereas predictive biomarkers help determine responses to a specific treatment. This review summarises prognostic biomarkers currently used in the more common paediatric solid tumours, with a brief commentary on the most relevant less common predictive biomarkers. MYCN amplification is the most important genetic alteration in neuroblastoma prognosis, and the histological classification devised by Shimada in 1999 is still used in routine diagnosis. Moreover, a new subgrouping of unfavourable histology neuroblastoma enables immunohistochemical characterisation of tumours with markedly different genetic features and prognosis. The predominant histology and commonly observed cytogenetic abnormalities are recognised outcome predictors in Wilms tumour. Evaluation for anaplasia, which is tightly associated with TP53 gene mutations and poor outcomes, is central in both the International Society of Paediatric Oncology and the Children's Oncology Group approaches to disease classification. Characterisation of distinct genotype-phenotype subclasses and critical mutations has expanded overall understanding of hepatoblastoma outcomes. The C1 subclass hepatoblastoma and CTNNB1 mutations are associated with good prognosis. In contrast, the C2 subclass, NFE2L2 mutations, TERT promoter mutations and high expression of oncofetal proteins and stem cell markers are associated with poor outcomes. Risk stratification in sarcomas is highly variable depending on the entity. The prognosis of rhabdomyosarcoma, for example, primarily depends on histological and molecular characteristics. Advances in our understanding of clinically significant biomarkers will translate into more precise diagnoses, improved risk stratification and more effective and less toxic treatment in this challenging group of patients.

Achaete-scute family bHLH transcription factor 2 activation promotes hepatoblastoma progression

Achaete-scute family bHLH transcription factor 2 (ASCL2) is highly expressed in hepatoblastoma (HB) tissues, but its role remains unclear. Thus, biological changes in the HB cell line HepG2 in response to induced ASCL2 expression were assessed. ASCL2 expression was induced in HepG2 cells using the Tet-On 3G system, which includes doxycycline. Cell viability, proliferation activity, mobility, and stemness were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony-formation, migration, invasion, and sphere-formation assays. Quantitative reverse-transcription polymerase chain reaction was used to assess the expression of markers for proliferation (CCND1 and MYC), epithelial-mesenchymal transition (EMT; SNAI1, TWIST1, and ZEB1), mesenchymal-epithelial transition (CDH1), and stemness (KLF4, POU5F1, and SOX9). Compared with the non-induced HepG2 cells, cells with induced ASCL2 expression showed significant increases in viability, colony number, migration area (%), and sphere number on days 7, 14, 8, and 7, respectively, and invasion area (%) after 90 h. Furthermore, induction of ASCL2 expression significantly upregulated CCND1, MYC, POU5F1, SOX9, and KLF4 expression on days 2, 2, 3, 3, and 5, respectively, and increased the ratios of SNAI1, TWIST1, and ZEB1 to CDH1 on day 5. ASCL2 promoted the formation of malignant phenotypes in HepG2 cells, which may be correlated with the upregulation of the Wnt signaling pathway-, EMT-, and stemness-related genes. ASCL2 activation may therefore be involved in the progression of HB.

Mutational signature, cancer driver genes mutations and transcriptomic subgroups predict hepatoblastoma survival

BACKGROUND

Hepatoblastoma is the most frequent pediatric liver cancer. The current treatments lead to 80% of survival rate at 5 years. In this study, we evaluated the clinical relevance of molecular features to identify patients at risk of chemoresistance, relapse and death of disease.

METHODS

All the clinical data of 86 children with hepatoblastoma were retrospectively collected. Pathological slides were reviewed, tumor DNA sequencing (by whole exome, whole genome or target) and transcriptomic profiling with RNAseq or 300-genes panel were performed. Associations between the clinical, pathological, mutational and transcriptomic data were investigated.

RESULTS

High-risk patients represented 44% of our series and the median age at diagnosis was 21.9 months (range: 0-208). Alterations of the WNT/ß-catenin pathway and of the 11p15.5 imprinted locus were identified in 98% and 74% of the tumors, respectively. Other cancer driver genes mutations were only found in less than 11% of tumors. After neoadjuvant chemotherapy, disease-specific survival and poor response to neoadjuvant chemotherapy were associated with 'Liver Progenitor' (p = 0.00049, p < 0.0001) and 'Immune Cold' (p = 0.0011, p < 0.0001) transcriptomic tumor subtypes, SBS35 cisplatin mutational signature (p = 0.018, p = 0.001), mutations in rare cancer driver genes (p = 0.0039, p = 0.0017) and embryonal predominant histological type (p = 0.0013, p = 0.0077), respectively. Integration of the clinical and molecular features revealed a cluster of molecular markers associated with resistance to chemotherapy and survival, enlightening transcriptomic 'Immune Cold' and Liver Progenitor' as a predictor of survival independent of the clinical features.

CONCLUSIONS

Response to neoadjuvant chemotherapy and survival in children treated for hepatoblastoma are associated with genomic and pathological features independently of the clinical features.

Summary of biological research on hepatoblastoma: a scoping review

Background

Hepatoblastoma is the most prevalent primary hepatic malignancy in children, comprising 80% of pediatric hepatic malignancies and 1% of all pediatric malignancies. However, traditional treatments have proven inadequate in effectively curing hepatoblastoma, leading to a poor prognosis.

Methods

A literature search was conducted on multiple electronic databases (PubMed and Google Scholar). A total of 86 articles were eligible for inclusion in this review.

Result

This review aims to consolidate recent developments in hepatoblastoma research, focusing on the latest advances in cancer-associated genomics, epigenetic studies, transcriptional programs and molecular subtypes. We also discuss the current treatment approaches and forthcoming strategies to address cancer-associated biological challenges.

Conclusion

To provide a comprehensive summary of the molecular mechanisms associated with hepatoblastoma occurrence, this review highlights three key aspects: genomics, epigenetics, and transcriptomics. Our review aims to facilitate the exploration of novel molecular mechanisms and the development of innovative clinical treatment strategies for hepatoblastoma.

Targeting G9a/DNMT1 methyltransferase activity impedes IGF2-mediated survival in hepatoblastoma

BACKGROUND

As the variable clinical outcome of patients with hepatoblastoma (HB) cannot be explained by genetics alone, the identification of drugs with the potential to effectively reverse epigenetic alterations is a promising approach to overcome poor therapy response. The gene ubiquitin like with PHD and ring finger domains 1 (UHRF1) represents an encouraging epigenetic target due to its regulatory function in both DNA methylation and histone modifications and its clinical relevance in HB.

METHODS

Patient-derived xenograft in vitro and in vivo models were used to study drug response. The mechanistic basis of CM-272 treatment was elucidated using RNA sequencing and western blot experiments.

RESULTS

We validated in comprehensive data sets that UHRF1 is highly expressed in HB and associated with poor outcomes. The simultaneous pharmacological targeting of UHRF1-dependent DNA methylation and histone H3 methylation by the dual inhibitor CM-272 identified a selective impact on HB patient-derived xenograft cell viability while leaving healthy fibroblasts unaffected. RNA sequencing revealed downregulation of the IGF2-activated survival pathway as the main mode of action of CM-272 treatment, subsequently leading to loss of proliferation, hindered colony formation capability, reduced spheroid growth, decreased migration potential, and ultimately, induction of apoptosis in HB cells. Importantly, drug response depended on the level of IGF2 expression, and combination assays showed a strong synergistic effect of CM-272 with cisplatin. Preclinical testing of CM-272 in a transplanted patient-derived xenograft model proved its efficacy but also uncovered side effects presumably caused by its strong antitumor effect in IGF2-driven tumors.

CONCLUSIONS

The inhibition of UHRF1-associated epigenetic traces, such as IGF2-mediated survival, is an attractive approach to treat high-risk HB, especially when combined with the standard-of-care therapeutic cisplatin.

EZH2 is a key component of hepatoblastoma tumor cell growth

BACKGROUND

Enhancer of zeste homolog 2 (EZH2) catalyzes the trimethylation of histone H3 at lysine 27 via the polycomb recessive complex 2 (PRC2) and plays a time-specific role in normal fetal liver development. EZH2 is overexpressed in hepatoblastoma (HB), an embryonal tumor. EZH2 can also promote tumorigenesis via a noncanonical, PRC2-independent mechanism via proto-oncogenic, direct protein interaction, including β-catenin. We hypothesize that the pathological activation of EZH2 contributes to HB propagation in a PRC2-independent manner.

METHODS AND RESULTS

We demonstrate that EZH2 promotes proliferation in HB tumor-derived cell lines through interaction with β-catenin. Although aberrant EZH2 expression occurs, we determine that both canonical and noncanonical EZH2 signaling occurs based on specific gene-expression patterns and interaction with SUZ12, a PRC2 component, and β-catenin. Silencing and inhibition of EZH2 reduce primary HB cell proliferation.

CONCLUSIONS

EZH2 overexpression promotes HB cell proliferation, with both canonical and noncanonical function detected. However, because EZH2 directly interacts with β-catenin in human tumors and EZH2 overexpression is not equal to SUZ12, it seems that a noncanonical mechanism is contributing to HB pathogenesis. Further mechanistic studies are necessary to elucidate potential pathogenic downstream mechanisms and translational potential of EZH2 inhibitors for the treatment of HB.

ZBTB7B is a permissive regulator of hepatocellular carcinoma initiation by repressing c-Jun expression and function

Hepatocarcinogenesis is a multi-step process. However, the regulators of hepatocellular carcinoma (HCC) initiation are understudied. Adult liver-specific gene expression was globally downregulated in HCC. We hypothesize that adult liver-specific genes, especially adult liver-enriched transcription factors may exert tumor-suppressive functions in HCC. In this study, we identify ZBTB7B, an adult liver-enriched transcription factor as a permissive regulator of HCC initiation. ZBTB7B is highly expressed in hepatocytes in adult livers, compared to fetal livers. To evaluate the functions of ZBTB7B in hepatocarcinogenesis, we performed hepatocyte-specific ZBTB7B knockout in hydrodynamic oncogene transfer-induced mouse liver cancer models. Hepatocyte-specific knockout of ZBTB7B promotes activated Akt and N-Ras-induced HCC development. Moreover, ZBTB7B deficiency sensitizes hepatocytes to a single oncogene Akt-induced oncogenic transformation and HCC initiation, which is otherwise incompetent in inducing HCC. ZBTB7B deficiency accelerates HCC initiation by down-regulating adult liver-specific gene expression and priming livers to a fetal-like state. The molecular mechanism underlying ZBTB7B functions in hepatocytes was investigated by integrated transcriptomic, phosphoproteomic, and chromatin immunoprecipitation-sequencing analyses. Integrative multi-omics analyses identify c-Jun as the core signaling node in ZBTB7B-deficient liver cancer initiation. c-Jun is a direct target of ZBTB7B essential to accelerated liver cancer initiation in ZBTB7B-deficient livers. Knockdown of c-Jun expression or dominant negative c-Jun expression delays HCC development in ZBTB7B-deficient livers. In addition, ZBTB7B competes with c-Jun for chromatin binding. Ectopic ZBTB7B expression attenuates the tumor-promoting functions of c-Jun. Expression of ZBTB7B signature, composed of 140 genes co-regulated by ZBTB7B and c-Jun, is significantly downregulated in early-stage HCCs compared to adjacent normal tissues, correlates to liver-specific gene expression, and is associated with good prognosis in human HCC. Thus, ZBTB7B functions as a permissive regulator of HCC initiation by directly regulating c-Jun expression and function.

Computed tomography imaging phenotypes of hepatoblastoma identified from radiomics signatures are associated with the efficacy of neoadjuvant chemotherapy

BACKGROUND

Though neoadjuvant chemotherapy has been widely used in the treatment of hepatoblastoma, there still lacks an effective way to predict its effect.

OBJECTIVE

To characterize hepatoblastoma based on radiomics image features and identify radiomics-based lesion phenotypes by unsupervised machine learning, intended to build a classifier to predict the response to neoadjuvant chemotherapy.

MATERIALS AND METHODS

In this retrospective study, we segmented the arterial phase images of 137 cases of pediatric hepatoblastoma and extracted the radiomics features using PyRadiomics. Then unsupervised k-means clustering was applied to cluster the tumors, whose result was verified by t-distributed stochastic neighbor embedding (t-SNE). The least absolute shrinkage and selection operator (LASSO) regression was used for feature selection, and the clusters were visually analyzed by radiologists. The correlations between the clusters, clinical and pathological parameters, and qualitative radiological features were analyzed.

RESULTS

Hepatoblastoma was clustered into three phenotypes (homogenous type, heterogenous type, and nodulated type) based on radiomics features. The clustering results had a high correlation with response to neoadjuvant chemotherapy (P=0.02). The epithelial ratio and cystic components in radiological features were also associated with the clusters (P=0.029 and 0.008, respectively).

CONCLUSIONS

This radiomics-based cluster system may have the potential to facilitate the precise treatment of hepatoblastoma. In addition, this study further demonstrated the feasibility of using unsupervised machine learning in a disease without a proper imaging classification system.

Preneoplastic liver colonization by 11p15.5 altered mosaic cells in young children with hepatoblastoma

Pediatric liver tumors are very rare tumors with the most common diagnosis being hepatoblastoma. While hepatoblastomas are predominantly sporadic, around 15% of cases develop as part of predisposition syndromes such as Beckwith-Wiedemann (11p15.5 locus altered). Here, we identify mosaic genetic alterations of 11p15.5 locus in the liver of hepatoblastoma patients without a clinical diagnosis of Beckwith-Wiedemann syndrome. We do not retrieve these alterations in children with other types of pediatric liver tumors. We show that mosaic 11p15.5 alterations in liver FFPE sections of hepatoblastoma patients display IGF2 overexpression and H19 downregulation together with an alteration of the liver zonation. Moreover, mosaic livers' microenvironment is enriched in extracellular matrix and angiogenesis. Spatial transcriptomics and single-nucleus RNAseq analyses identify a 60-gene signature in 11p15.5 altered hepatocytes. These data provide insights for 11p15.5 mosaicism detection and its functional consequences during the early steps of carcinogenesis.

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.

Characterisation of Aberrant Metabolic Pathways in Hepatoblastoma Using Liquid Chromatography and Tandem Mass Spectrometry (LC-MS/MS)

Hepatoblastoma (HB) is a rare childhood tumour with an evolving molecular landscape. We present the first comprehensive metabolomic analysis using untargeted and targeted liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-MS/MS) of paired tumour and non-tumour surgical samples in HB patients (n = 8 pairs). This study demonstrates that the metabolomic landscape of HB is distinct from that of non-tumour (NT) liver tissue, with 35 differentially abundant metabolites mapping onto pathways such as fatty acid transport, glycolysis, the tricarboxylic acid (TCA) cycle, branched-chain amino acid degradation and glutathione synthesis. Targeted metabolomics demonstrated reduced short-chain acylcarnitines and a relative accumulation of branched-chain amino acids. Medium- and long-chain acylcarnitines in HB were similar to those in NT. The metabolomic changes reported are consistent with previously reported transcriptomic data from tumour and non-tumour samples (49 out of 54 targets) as well as metabolomic data obtained using other techniques. Gene set enrichment analysis (GSEA) from RNAseq data (n = 32 paired HB and NT samples) demonstrated a downregulation of the carnitine metabolome and immunohistochemistry showed a reduction in CPT1a (n = 15 pairs), which transports fatty acids into the mitochondria, suggesting a lack of utilisation of long-chain fatty acids in HB. Thus, our findings suggest a reduced metabolic flux in HB which is corroborated at the gene expression and protein levels. Further work could yield novel insights and new therapeutic targets.

Biology of childhood hepatoblastoma and the search for novel treatments

Our research laboratory has a longstanding interest in developmental disorders and embryonic tumors, and recent efforts have focused on the pathogenesis of pediatric liver tumors. This review focuses on hepatoblastoma (HB), the most common pediatric liver malignancy. Despite advances in treatment, patients with metastatic HB have a poor prognosis, and survivors often have permanent side effects attributable to chemotherapy. In an effort to improve survival and lessen long-term complications of HB, we have searched for novel molecular vulnerabilities using a combination of patient derived cell lines, metabolomics, and RNA sequencing of human samples at diagnosis and follow-up. These studies have shed light on pathogenesis and identified putative targets for future therapies in children with advanced HB.

Identification and experimental validation of druggable epigenetic targets in hepatoblastoma

BACKGROUND & AIMS

Hepatoblastoma (HB) is the most frequent childhood liver cancer. Patients with aggressive tumors have limited therapeutic options; therefore, a better understanding of HB pathogenesis is needed to improve treatment. HBs have a very low mutational burden; however, epigenetic alterations are increasingly recognized. We aimed to identify epigenetic regulators consistently dysregulated in HB and to evaluate the therapeutic efficacy of their targeting in clinically relevant models.

METHODS

We performed a comprehensive transcriptomic analysis of 180 epigenetic genes. Data from fetal, pediatric, adult, peritumoral (n = 72) and tumoral (n = 91) tissues were integrated. Selected epigenetic drugs were tested in HB cells. The most relevant epigenetic target identified was validated in primary HB cells, HB organoids, a patient-derived xenograft model, and a genetic mouse model. Transcriptomic, proteomic and metabolomic mechanistic analyses were performed.

RESULTS

Altered expression of genes regulating DNA methylation and histone modifications was consistently observed in association with molecular and clinical features of poor prognosis. The histone methyltransferase G9a was markedly upregulated in tumors with epigenetic and transcriptomic traits of increased malignancy. Pharmacological targeting of G9a significantly inhibited growth of HB cells, organoids and patient-derived xenografts. Development of HB induced by oncogenic forms of β-catenin and YAP1 was ablated in mice with hepatocyte-specific deletion of G9a. We observed that HBs undergo significant transcriptional rewiring in genes involved in amino acid metabolism and ribosomal biogenesis. G9a inhibition counteracted these pro-tumorigenic adaptations. Mechanistically, G9a targeting potently repressed the expression of c-MYC and ATF4, master regulators of HB metabolic reprogramming.

CONCLUSIONS

HBs display a profound dysregulation of the epigenetic machinery. Pharmacological targeting of key epigenetic effectors exposes metabolic vulnerabilities that can be leveraged to improve the treatment of these patients.

IMPACT AND IMPLICATIONS

In spite of recent advances in the management of hepatoblastoma (HB), treatment resistance and drug toxicity are still major concerns. This systematic study reveals the remarkable dysregulation in the expression of epigenetic genes in HB tissues. Through pharmacological and genetic experimental approaches, we demonstrate that the histone-lysine-methyltransferase G9a is an excellent drug target in HB, which can also be harnessed to enhance the efficacy of chemotherapy. Furthermore, our study highlights the profound pro-tumorigenic metabolic rewiring of HB cells orchestrated by G9a in coordination with the c-MYC oncogene. From a broader perspective, our findings suggest that anti-G9a therapies may also be effective in other c-MYC-dependent tumors.

BEX1 supports the stemness of hepatoblastoma by facilitating Warburg effect in a PPARγ/PDK1 dependent manner

BACKGROUND

Hepatoblastoma (HB) is a highly aggressive paediatric malignancy that exhibits a high presence of cancer stem cells (CSCs), which related to tumour recurrence and chemotherapy resistance. Brain expressed X-linked protein 1 (BEX1) plays a pivotal role in ciliogenesis, axon regeneration and differentiation of neural stem cells. However, the role of BEX1 in metabolic and stemness programs in HB remains unclear.

METHODS

BEX1 expression in human and mouse HB was analyzed using gene expression profile data from NCBI GEO and immunohistochemical validation. Seahorse extracellular flux analyzer, ultra-high-performance liquid-chromatography mass spectrometry (LC-MS), flow cytometry, qRT-PCR, Western Blot, sphere formation assay, and diluted xenograft tumour formation assay were used to analyze metabolic and stemness features.

RESULTS

Our results indicated that overexpression of BEX1 significantly enhanced the Warburg effect in HB cells. Furthermore, glycolysis inhibition largely attenuated the effects of BEX1 on HB cell growth and self-renewal, suggesting that BEX1 promotes stemness maintenance of HB cells by regulating the Warburg effect. Mechanistically, BEX1 enhances Warburg effect through the downregulation of peroxisome proliferator-activated receptor-gamma (PPARγ). Furthermore, pyruvate dehydrogenase kinase isozyme 1 (PDK1) is required for PPARγ-induced inhibition of Warburg effect in HB. In addition, BEX1 supports the stemness of HB by enhancing Warburg effect in a PPARγ/PDK1 dependent manner.

CONCLUSIONS

HB patients with high BEX1 and PDK1 expression had a poor prognosis. BEX1 promotes the stemness maintenance of HB cells via modulating the Warburg effect, which depends on PPARγ/PDK1 axis. Pioglitazone could be used to target BEX1-mediated stemness properties in HB by upregulating PPARγ.

Children's Oncology Group's 2023 blueprint for research: Liver tumors

Liver tumors account for approximately 1%-2% of all pediatric malignancies, with the two most common tumors being hepatoblastoma (HB) and hepatocellular carcinoma (HCC). Previous Children's Oncology Group studies have meaningfully contributed to the current understanding of disease pathophysiology and treatment, laying groundwork for the ongoing prospective international study of both HB and HCC. Future work is focused on elucidating the biologic underpinnings of disease to support an evolution in risk categorization, advancements in the multidimensional care required to treat these patients, and the discovery of novel therapies.

Alternative Splicing of lncRNAs From SNHG Family Alters snoRNA Expression and Induces Chemoresistance in Hepatoblastoma

BACKGROUND & AIMS

Hepatoblastoma (HB) is a common pediatric malignant liver tumor that is characterized by a low level of genetic mutations. Alternative splicing (AS) has been shown to be closely associated with cancer progression, especially in tumors with a low mutational burden. However, the role of AS in HB remains unknown.

METHODS

Transcriptome sequencing was performed on 5 pairs of HB tissues and matched non-tumor tissues to delineate the AS landscape in HB. AS events were validated in 92 samples from 46 patients. RNA pull-down and RNA immunoprecipitation assays were carried out to identify splicing factors that regulate the AS of small nucleolar RNA host genes (SNHG). Patient-derived organoids (PDOs) were established to investigate the role of the splicing factor polyadenylate-binding nuclear protein 1 (PABPN1).

RESULTS

This study uncovered aberrant alternative splicing in HB, including lncRNAs from SNHG family that undergo intron retention in HB. Further investigations revealed that PABPN1, a significantly upregulated RNA binding protein, interacts with splicing machinery in HB, inducing the intron retention of these SNHG RNAs and the downregulation of intronic small nucleolar RNAs (snoRNAs). Functionally, PABPN1 acts as an oncofetal splicing regulator in HB by promoting cell proliferation and DNA damage repair via inducing the intron retention of SNHG19. Knock-down of PABPN1 increases the cisplatin sensitivity of HB PDOs.

CONCLUSIONS

Our findings revealed the role of intron retention in regulating snoRNA expression in hepatoblastoma, explained detailed regulatory mechanism between PABPN1 and the intron retention of SNHG RNAs, and provided insight into the development of new HB treatment options.

Genome-wide mapping of cancer dependency genes and genetic modifiers of chemotherapy in high-risk hepatoblastoma

A lack of relevant genetic models and cell lines hampers our understanding of hepatoblastoma pathogenesis and the development of new therapies for this neoplasm. Here, we report an improved MYC-driven hepatoblastoma-like murine model that recapitulates the pathological features of embryonal type of hepatoblastoma, with transcriptomics resembling the high-risk gene signatures of the human disease. Single-cell RNA-sequencing and spatial transcriptomics identify distinct subpopulations of hepatoblastoma cells. After deriving cell lines from the mouse model, we map cancer dependency genes using CRISPR-Cas9 screening and identify druggable targets shared with human hepatoblastoma (e.g., CDK7, CDK9, PRMT1, PRMT5). Our screen also reveals oncogenes and tumor suppressor genes in hepatoblastoma that engage multiple, druggable cancer signaling pathways. Chemotherapy is critical for human hepatoblastoma treatment. A genetic mapping of doxorubicin response by CRISPR-Cas9 screening identifies modifiers whose loss-of-function synergizes with (e.g., PRKDC) or antagonizes (e.g., apoptosis genes) the effect of chemotherapy. The combination of PRKDC inhibition and doxorubicin-based chemotherapy greatly enhances therapeutic efficacy. These studies provide a set of resources including disease models suitable for identifying and validating potential therapeutic targets in human high-risk hepatoblastoma.

GepLiver: an integrative liver expression atlas spanning developmental stages and liver disease phases

Chronic liver diseases usually developed through stepwise pathological transitions under the persistent risk factors. The molecular changes during liver transitions are pivotal to improve liver diagnostics and therapeutics yet still remain elusive. Cumulative large-scale liver transcriptomic studies have been revealing molecular landscape of various liver conditions at bulk and single-cell resolution, however, neither single experiment nor databases enabled thorough investigations of transcriptomic dynamics along the progression of liver diseases. Here we establish GepLiver, a longitudinal and multidimensional liver expression atlas integrating expression profiles of 2469 human bulk tissues, 492 mouse samples, 409,775 single cells from 347 human samples and 27 liver cell lines spanning 16 liver phenotypes with uniformed processing and annotating methods. Using GepLiver, we have demonstrated dynamic changes of gene expression, cell abundance and crosstalk harboring meaningful biological associations. GepLiver can be applied to explore the evolving expression patterns and transcriptomic features for genes and cell types respectively among liver phenotypes, assisting the investigation of liver transcriptomic dynamics and informing biomarkers and targets for liver diseases.

Single-cell transcriptomics uncovers cellular architecture and developmental trajectories in hepatoblastoma

BACKGROUND AND AIMS

Hepatoblastoma (HB) is the predominant type of childhood liver cancer. Treatment options for the clinically advanced HB remain limited. We aimed to dissect the cellular and molecular basis underlying HB oncogenesis and heterogeneity at the single-cell level, which could facilitate a better understanding of HB at both the biological and clinical levels.

APPROACH AND RESULTS

Single-cell transcriptome profiling of tumor and paired distal liver tissue samples from five patients with HB was performed. Deconvolution analysis was used for integrating the single-cell transcriptomic profiles with the bulk transcriptomes of our HB cohort of post-neoadjuvant chemotherapy tumor samples. A single-cell transcriptomic landscape of early human liver parenchymal development was established for exploring the cellular root and hierarchy of HB oncogenesis. As a result, seven distinct tumor cell subpopulations were annotated, and an effective HB subtyping method was established based on their compositions. A HB tumor cell hierarchy was further revealed to not only fit with the classical cancer stem cell (CSC) model but also mirror the early human liver parenchymal development. Moreover, FACT inhibition, which could disrupt the oncogenic positive feedback loop between MYC and SSRP1 in HB, was identified as a promising epigenetic-targeted therapeutic strategy against the CSC-like HB1-Pro-like1 subpopulation and its related high-risk "Pro-like1" subtype of HB.

CONCLUSIONS

Our findings illustrate the cellular architecture and developmental trajectories of HB via integrative bulk and single-cell transcriptome analyses, thus establishing a resourceful framework for the development of targeted diagnostics and therapeutics in the future.

Intratumoral erythroblastic islands restrain anti-tumor immunity in hepatoblastoma

Erythroblastic islands (EBIs) are the specialized structures for erythropoiesis, but they have never been found functional in tumors. As the most common pediatric liver malignancy, hepatoblastoma (HB) requires more effective and safer therapies to prevent progression and the lifelong impact of complications on young children. However, developing such therapies is impeded by a lack of comprehensive understanding of the tumor microenvironment. By single-cell RNA sequencing of 13 treatment-naive HB patients, we discover an immune landscape characterized by aberrant accumulation of EBIs, formed by VCAM1⁺ macrophages and erythroid cells, which is inversely correlated with survival of HB. Erythroid cells inhibit the function of dendritic cells (DCs) via the LGALS9/TIM3 axis, leading to impaired anti-tumor T cell immune responses. Encouragingly, TIM3 blockades relieve the inhibitory effect of erythroid cells on DCs. Our study provides an immune evasion mechanism mediated by intratumoral EBIs and proposes TIM3 as a promising therapeutic target for HB.

Dihydromyricetin functions as a tumor suppressor in hepatoblastoma by regulating SOD1/ROS pathway

Background

Hepatoblastoma has an unsatisfactory prognosis, and traditional chemotherapy has strong side effects. Dihydromyricetin is a flavonoid extracted from a woody vine of the genus Serpentine in the family Vitaceae, with effects such as preventing alcoholic liver and reducing the incidence of liver cancer. However, the effect of DHM on hepatoblastoma and its specific pathway are still unclear.

Purpose

The purpose of this study was to investigate the effects of DHM on children's hepatoblastoma and its related mechanisms.

Methods

CCK-8 assays were used to measure proliferation. Apoptosis and reactive oxygen species (ROS) were analyzed by flow cytometry. Apoptotic cells were observed using Hoechst 33342 staining and fluorescence microscopy. Protein expression levels in HuH-6 and HepG2 cells were determined by western blotting.

Results

We found that DHM was able to inhibit the growth and increase cellular mortality in HuH-6 and HepG2 cells. Furthermore, DHM decreased the intracellular ROS level and increased the expression of SOD1. ROS scavenger NAC promoted apoptosis, while the use of SOD1 inhibitor LCS-1 weakened the ROS scavenging effect of DHM , and to some extent reduced the killing effect of DHM on hepatoblastoma cells.

Conclusion

These results suggest that regulating SOD1/ROS pathway to induce apoptosis is one of the potential mechanisms of DHM as a tumor suppressor in hepatoblastoma. Therefore, DHM may be a novel candidate for inhibiting hepatoblastoma growth and deserves further study.