Project description:Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. β-catenin is widely thought to be a major oncogene in HCC based on the frequency of mutations associated with aberrant Wnt signaling in HCC patients. Challenging this model, our data reveal that β-catenin nuclear accumulation is restricted to the late stage of the disease. Until then, β-catenin is primarily located at the plasma membrane in complex with multiple cadherin family members where it drives tumor cell survival by enhancing the signaling of growth factor receptors such as EGFR. Therefore, our study reveals the evolving nature of β-catenin in HCC to establish it as a compound tumor promoter during the progression of the disease.
Project description:Hepatocellular carcinoma (HCC) is a highly heterogeneous disease, and prior attempts to develop genomic-based classification for HCC have yielded highly divergent results, indicating difficulty in identifying unified molecular anatomy. We performed a meta-analysis of gene expression profiles in data sets from eight independent patient cohorts across the world. In addition, aiming to establish the real world applicability of a classification system, we profiled 118 formalin-fixed, paraffin-embedded tissues from an additional patient cohort. A total of 603 patients were analyzed, representing the major etiologies of HCC (hepatitis B and C) collected from Western and Eastern countries. We observed three robust HCC subclasses (termed S1, S2, and S3), each correlated with clinical parameters such as tumor size, extent of cellular differentiation, and serum alpha-fetoprotein levels. An analysis of the components of the signatures indicated that S1 reflected aberrant activation of the WNT signaling pathway, S2 was characterized by proliferation as well as MYC and AKT activation, and S3 was associated with hepatocyte differentiation. Functional studies indicated that the WNT pathway activation signature characteristic of S1 tumors was not simply the result of beta-catenin mutation but rather was the result of transforming growth factor-beta activation, thus representing a new mechanism of WNT pathway activation in HCC. These experiments establish the first consensus classification framework for HCC based on gene expression profiles and highlight the power of integrating multiple data sets to define a robust molecular taxonomy of the disease. Surgically resected 118 tumor tissues from patients with hepatocellular carcinoma (HCC)
Project description:The orphan nuclear receptor NR2E3 (Nuclear receptor subfamily 2 group E, Member 3) is an epigenetic player essential for p53 activation during liver injuries through its modulation of chromatin accessibility. Nonetheless, a precise tumor suppressive and epigenetic role of NR2E3 in hepatocellular carcinoma (HCC) remains unclear. HCC patients expressing low NR2E3 exhibit unfavorable clinical outcomes, aligning with heightened activation of the WNT/β-catenin signaling pathway. The murine HCC models utilizing NR2E3 knockout mice consistently exhibits accelerated liver tumor formation and progression accompanied by enhanced activation of WNT/β-catenin signaling pathway and inactivation of p53 signaling pathway. At cellular level, the loss of NR2E3 increases the acquisition of aggressive cancer cell phenotype and tumorigenicity and upregulates key genes in the WNT/β-catenin pathway with enhanced chromatin accessibility. This event is mediated through increased formation of active transcription complex involving Sp1, β-catenin, and p300, a histone acetyltransferase, on the promoters of target genes. These findings demonstrate that the loss of NR2E3 promotes WNT/β-catenin signaling activation at cellular, organismal, and clinical levels. In summary, NR2E3 is a novel tumor suppressor that maintains epigenetic homeostasis, thereby preventing activation of WNT/β-catenin signaling that promotes HCC formation and progression.
Project description:CTNNB1 is the most frequently mutated gene in hepatocellular carcinoma (HCC). However, its clinical relevance remains controversial. We determined an evolutionarily conserved β-catenin signature by comparative analysis of gene expression data from human HCC and a mouse model (GSE43628). We generated gene expression data from the tumors of 88 HCC patients who underwent surgical resection as the primary treatment. We used these gene expression data to develop a new prognostification model for prognosis of HCC after surgery. We generated gene expression data from the tumors of 88 HCC patients who underwent surgical resection as the primary treatment.
Project description:CTNNB1 is the most frequently mutated gene in hepatocellular carcinoma (HCC). However, its clinical relevance remains controversial. We determined an evolutionarily conserved β-catenin signature by comparative analysis of gene expression data from human HCC (GSE43619) and a mouse model.
Project description:We previously reported that the nuclear receptor NR2E3 activates the tumor suppressor gene p53 by modulating chromatin accessibility. In this study, we further investigated the impact of NR2E3 deficiency on chromatin accessibility. We used FAIRE-seq (Formaldehyde-Assisted Isolation of Regulatory Elements) analysis to find that NR2E3 loss increased chromatin accessibility in genomic regions interacting with various transcription factors, including Sp1. Additionally, NR2E3 loss enhanced chromatin accessibility and expression of crucial genes, such as JAK1 and PPARD, essential for WNT-β-catenin signaling pathway activation by facilitating interactions between Sp1 and Myc transcription factors at their promoters. Gene set enrichment analysis (GSEA) on mouse liver tumor tissues from wild-type and NR2E3 knockout mice confirmed that NR2E3 ablation activated WNT-β-catenin signaling pathways in vivo. Kaplan-Meier survival analysis using liver cancer patient data from two clinical datasets confirmed that patients with low NR2E3 expression exhibited increased WNT-β-catenin signaling activation, associated with adverse clinical outcomes. These findings highlight NR2E3 as a crucial tumor suppressor gene in hepatocellular carcinoma (HCC), primarily restraining WNT-β-catenin signaling pathway activation to maintain epigenetic homeostasis and contribute to HCC development. Our results prove NR2E3's critical role in liver cancer pathogenesis by regulating WNT-β-catenin signaling pathways and epigenetic equilibrium maintenance. The Formaldehyde Assisted Isolation of Regulatory Elemens (FAIRE)-Seqwas performed using control (shCT) and NR2E3-depleted (shNR2E3) HepG2 cells.
Project description:CTNNB1 is the most frequently mutated gene in hepatocellular carcinoma (HCC). However, its clinical relevance remains controversial. We determined an evolutionarily conserved β-catenin signature by comparative analysis of gene expression data from human HCC and a mouse model (GSE43628). We generated gene expression data from the tumors of 88 HCC patients who underwent surgical resection as the primary treatment. We used these gene expression data to develop a new prognostification model for prognosis of HCC after surgery.
Project description:Background & Aims: Extracellular vesicles (EVs) play a pivotal role in connecting tumor cells and their local and distant microenvironment. Here, we aimed to understand the role and molecular basis of patient-derived EVs in modulating cancer stemness and tumorigenesis in the context of hepatocellular carcinoma (HCC). Methods: EVs were isolated, quantified and characterized from patients’ sera. EVs were tested vigorously, both in vitro and in vivo, by various functional assays. Proteomic analysis was performed to identify the functional components of EVs. The expression level of polymeric immunoglobulin receptor (pIgR) in circulating EVs, tumor and non-tumorous tissues of HCC patients was determined by ELISA, immunoblotting, immunohistochemistry and quantitative PCR. The functional role and underlying mechanism of EVs with an enhanced pIgR expression was elucidated. Blockage of EV-pIgR with neutralizing antibody was performed in nude mice implanted with patient-derived tumor xenograft (PDTX). Results: Circulating EVs of late-stage HCC (L-HCC) patient had significantly elevated pIgR expression when compared to the EVs released by control individuals. The augmenting effect of L-HCC patient in cancer stemness and tumorigenesis was hindered by anti-pIgR antibody. EVs enriched with pIgR consistently promoted cancer stemness and cancerous phenotypes in the recipient cells. Mechanistically, EV-pIgR-induced cancer aggressiveness was abrogated by Akt and β-catenin inhibitors, ascertaining the role of EV-pIgR through the activation of PDK1/Akt/GSK3β/β-catenin signaling axis. Furthermore, anti-pIgR neutralizing antibody attenuated the tumor growth in mice implanted with PDTX. Conclusion: The study illustrates an unrevealed role of EV-pIgR in regulating cancer stemness and aggressiveness, in which EV-pIgR activates PDK1/Akt/GSK3β/β-catenin signaling cascades. The blockage of intercellular communications mediated by EV-pIgR in the tumor microenvironment may provide a new therapeutic strategy for cancer patients.
Project description:Up to 41% of hepatocellular carcinomas (HCCs) result from activating mutations in the CTNNB1 gene encoding β-catenin. β-catenin has dual cellular functions as a component of the Wnt signaling pathway and adherens junctions. HCC-associated CTNNB1 mutations stabilize the β-catenin protein, leading to nuclear and/or cytoplasmic localization of β-catenin and downstream activation of Wnt target genes. In patient HCC samples, β-catenin nuclear and cytoplasmic localization are typically patchy, even among HCC with highly active CTNNB1 mutations. The functional and clinical relevance of this heterogeneity in β-catenin activation are not well understood. To define mechanisms of β-catenin-driven HCC initiation, we generated a Cre-lox system that enabled switching on activated β-catenin in 1) a small number of hepatocytes in early development; or 2) the majority of hepatocytes in later development or adulthood. We discovered that switching on activated β-catenin in a subset of larval hepatocytes was sufficient to drive HCC initiation. To determine the role of Wnt/β-catenin signaling heterogeneity later in hepatocarcinogenesis, we performed RNA-seq analysis of zebrafish β-catenin-driven HCC. Ingenuity Pathway Analysis of differentially expressed genes in the Cre-lox HCC model revealed that “Cancer” and “Liver Tumor” categories were significantly altered, indicating transcriptional similarities with human HCC and other vertebrate HCC models. At the single-cell level, 2.9% to 15.2% of hepatocytes from zebrafish β-catenin-driven HCC expressed two or more of the Wnt target genes axin2, mtor, glula, myca, and wif1, indicating focal activation of Wnt signaling in established tumors. Thus, heterogeneous β-catenin activation drives HCC initiation and persists throughout hepatocarcinogenesis.