Centromere protein F promotes progression of hepatocellular carcinoma through ERK and cell cycle-associated pathways.

Hepatocellular carcinoma (HCC) is one of the deadliest cancer types worldwide. The centromere proteins (CENPs) are critical for the mitosis-related protein complex and are involved in kinetochore assembly and spindle checkpoint signaling during mitosis. However, the clinical significance of CENPs in the recurrence and progression of HCC remains poorly understood. Here, we examined the expression of all CENPs and their association with recurrence and survival of HCC patients using the global gene expression profile dataset established in our laboratory. The effect of silencing CENPF on cell viability, migration, and epithelial-mesenchymal transition (EMT) were detected using CCK-8, transwell, and western blot, respectively. RT-qPCR and western blot were performed to confirm the silencing of CENPF and the relationship between STAT5A and CENPF, while tumorigenesis was tested using the HCC Huh7 xenograft mouse model. Most of the CENPs is overexpressed in HCC, and overexpression of CENPF was significantly associated with the poor survival of HCC patients. CENPF promoted HCC cell lines migration and EMT progression. Knockdown CENPF inhibited cell growth activity against human HCC cells in vitro and xenograft tumors in vivo. Bioinformatics analysis revealed that CENPF genes are enriched in the cell cycle. Silencing CENPF arrested cell cycle at the G2/M phase and inhibited Cyclin B1 and Cyclin E1 expressions. Meanwhile, silencing CENPF prohibited phosphorylation of ERK and the expression of NEK2. Additionally, we found that STAT5A down-regulated CENPF expression and inhibited cancer cell growth viability. In conclusion, our data suggested that CENPF could be potentially developed into a theranostic biomarker to tackle HCC progression.

Cytokinesis regulators as potential diagnostic and therapeutic biomarkers for human hepatocellular carcinoma.

Cytokinesis, the final step of mitosis, is critical for maintaining the ploidy level of cells. Cytokinesis is a complex, highly regulated process and its failure can lead to genetic instability and apoptosis, contributing to the development of cancer. Human hepatocellular carcinoma is often accompanied by a high frequency of aneuploidy and the DNA ploidy pattern observed in human hepatocellular carcinoma results mostly from impairments in cytokinesis. Many key regulators of cytokinesis are abnormally expressed in human hepatocellular carcinoma, and their expression levels are often correlated with patient prognosis. Moreover, preclinical studies have demonstrated that the inhibition of key cytokinesis regulators can suppress the growth of human hepatocellular carcinoma. Here, we provide an overview of the current understanding of the signaling networks regulating cytokinesis, the key cytokinesis regulators involved in the initiation and development of human hepatocellular carcinoma, and their applications as potential diagnostic and therapeutic biomarkers.

Hypoxia-induced modulation of glucose transporter expression impacts 18F-fluorodeoxyglucose PET-CT imaging in hepatocellular carcinoma.

PURPOSE: To investigate the molecular mechanisms underlying the variable standard uptake value (SUV) of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) imaging in hepatocellular carcinoma (HCC) and whether hypoxia-induced glucose transporter expression contributes to the progression of HCC and the rate of glycolysis in HCC cells. MATERIALS AND METHODS: Sixteen HCC specimens obtained from patients who underwent pre-treatment staging with 18F-FDG PET-CT imaging were divided into high maximum SUV (SUVmax > 8) and low SUVmax (SUVmax < 5) groups and employed for whole-genome gene expression profiling using GeneChip Human Genome U133 Plus 2.0 Arrays. The relationship between SUVmax and the expression of glucose transporters 1 and 3 (GLUT1 and GLUT3) was further validated using immunohistochemical analysis. The expression of GLUT1 and GLUT3 in different HCC cells under hypoxia and normoxia conditions were monitored by quantitative reverse transcription PCR (RT-qPCR). Glycolysis and FDG uptake by HCC cells were measured using the Seahorse XF glycolysis stress test and 18F-FDG PET-CT imaging. The effect of GLUT1 and GLUT3 on glucose uptake in HCC cells was examined using the fluorescent D-glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) followed by detection of fluorescence produced by the cells using flow cytometry. RESULTS: Glucose transporters are differentially expressed between samples from HCC patients with high and low SUVmax. In particular, over-expression of GLUT1 and GLUT3 in high SUVmax patients was correlated with high glucose uptake and overall survival. The expression of GLUT1 and GLUT3 was significantly induced by hypoxia in different HCC cells. High expression of GLUT1 and GLUT3 in HCC cells were correlated with high rates of glycolysis and 18F-FDG uptake. Therefore, our data suggested that hypoxia-induced glucose transporters expression could result in the variations of 18F-FDG PET-CT imaging and progression of HCC, contributing to more aggressive disease phenotypes like large tumor size, recurrence, and poor survival. CONCLUSION: Over-expression of GLUT1 and GLUT3 significantly increase glucose uptake in HCC cells. Hypoxia-induced glucose transporters expression may therefore be a contributing variable in 18F-FDG PET-CT imaging and progression in HCC.

Clinical and metabolomics analysis of hepatocellular carcinoma patients with diabetes mellitus.

INTRODUCTION: Diabetes and cancer are among the most frequent causes of death worldwide. Recent epidemiological findings have indicated a link between diabetes and cancer in several organs, particularly the liver. A number of epidemiological studies have demonstrated that diabetes is an established independent risk factor for hepatocellular carcinoma (HCC). However, the metabolites connecting diabetes and HCC remains less well understood. OBJECTIVES: The study aimed to identify clinical and metabolomics differences of HCC from patients with/without diabetes using comprehensive global metabolomics analysis. METHODS: Metabolite profiling was conducted with the Metabolon platform for 120 human diabetes/non-diabetes HCC tumor/normal tissues. Standard statistical analyses were performed using the Partek Genomics Suite on log-transformed data. Principal component analysis (PCA) was conducted using all and dysregulated metabolites. RESULTS: We identified a group of metabolites that are differentially expressed in the tumor tissues of diabetes HCC compared to non-diabetes HCC patients. Meanwhile, we also identified a group of metabolites that are differentially expressed in the matched normal liver tissues of diabetes HCC compared to non-diabetes HCC patients. Some metabolites are consistently dysregulated in the tumor or matched normal tissues of HCC with or without diabetes. However, some metabolites, including 2-hydroxystearate, were only overexpressed in the tumor tissues of HCC with diabetes and associated with the glucose level. CONCLUSION: Metabolic profiling identifies distinct dysregulated metabolites in HCC patients with/without diabetes.

Relevance of a TCGA-derived Glioblastoma Subtype Gene-Classifier among Patient Populations.

Glioblastoma multiforme (GBM), a deadly cancer, is the most lethal and common malignant brain tumor, and the leading cause of death in adult brain tumors. While genomic data continues to rocket, clinical application and translation to patient care are lagging behind. Big data now deposited in the TCGA network offers a window to generate novel clinical hypotheses. We hypothesized that a TCGA-derived gene-classifier can be applied across different gene profiling platforms and population groups. This gene-classifier validated three robust GBM-subtypes across six different platforms, among Caucasian, Korean and Chinese populations: Three Caucasian-predominant TCGA-cohorts (Affymetrix U133A = 548, Agilent Custom-Array = 588, RNA-seq = 168), and three Asian-cohorts (Affymetrix Human Gene 1.0ST-Array = 61, Illumina = 52, Agilent 4 × 44 K = 60). To understand subtype-relevance in patient therapy, we investigated retrospective TCGA patient clinical sets. Subtype-specific patient survival outcome was similarly poor and reflected the net result of a mixture of treatment regimens with/without surgical resection. As a proof-of-concept, in subtype-specific patient-derived orthotopic xenograft (PDOX) mice, Classical-subtype demonstrated no survival difference comparing radiation-therapy versus temozolomide monotherapies. Though preliminary, a PDOX model of Proneural/Neural-subtype demonstrated significantly improved survival with temozolomide compared to radiation-therapy. A larger scale study using this gene-classifier may be useful in clinical outcome prediction and patient selection for trials based on subtyping.

Insights into the etiology-associated gene regulatory networks in hepatocellular carcinoma from The Cancer Genome Atlas.

BACKGROUND AND AIM: Hepatitis B virus (HBV), hepatitis C virus, alcohol consumption, and non-alcoholic fatty liver disease are the major known risk factors for hepatocellular carcinoma (HCC). There have been very few studies comparing the underlying biological mechanisms associated with the different etiologies of HCC. In this study, we hypothesized the existence of different regulatory networks associated with different liver disease etiologies involved in hepatocarcinogenesis. METHODS: Using upstream regulatory analysis tool in ingenuity pathway analysis software, upstream regulators (URs) were predicted using differential expressed genes for HCC to facilitate the interrogation of global gene regulation. RESULTS: Analysis of regulatory networks for HBV HCC revealed E2F1 as activated UR, regulating genes involved in cell cycle and DNA replication, and HNF4A and HNF1A as inhibited UR. In hepatitis C virus HCC, interferon-γ, involved in cellular movement and signaling, was activated, while IL1RN, mitogen-activated protein kinase 1 involved in interleukin 22 signaling and immune response, was inhibited. In alcohol consumption HCC, ERBB2 involved in inflammatory response and cellular movement was activated, whereas HNF4A and NUPR1 were inhibited. For HCC derived from non-alcoholic fatty liver disease, miR-1249-5p was activated, and NUPR1 involved in cell cycle and apoptosis was inhibited. The prognostic value of representative genes identified in the regulatory networks for HBV HCC can be further validated by an independent HBV HCC dataset established in our laboratory with survival data. CONCLUSIONS: Our study identified functionally distinct candidate URs for HCC developed from different etiologic risk factors. Further functional validation studies of these regulatory networks could facilitate the management of HCC towards personalized medicine.

Interleukin-13 receptor alpha 2 cooperates with EGFRvIII signaling to promote glioblastoma multiforme.

The interleukin-13 receptor alpha2 (IL-13Rα2) is a cancer-associated receptor overexpressed in human glioblastoma multiforme (GBM). This receptor is undetectable in normal brain which makes it a highly suitable target for diagnostic and therapeutic purposes. However, the pathological role of this receptor in GBM remains to be established. Here we report that IL-13Rα2 alone induces invasiveness of human GBM cells without affecting their proliferation. In contrast, in the presence of the mutant EGFR (EGFRvIII), IL-13Rα2 promotes GBM cell proliferation in vitro and in vivo. Mechanistically, the cytoplasmic domain of IL-13Rα2 specifically binds to EGFRvIII, and this binding upregulates the tyrosine kinase activity of EGFRvIII and activates the RAS/RAF/MEK/ERK and STAT3 pathways. Our findings support the "To Go or To Grow" hypothesis whereby IL-13Rα2 serves as a molecular switch from invasion to proliferation, and suggest that targeting both receptors with STAT3 signaling inhibitor might be a therapeutic approach for the treatment of GBM.

Simultaneous silencing of ACSL4 and induction of GADD45B in hepatocellular carcinoma cells amplifies the synergistic therapeutic effect of aspirin and sorafenib.

Sorafenib is currently the only US Food and Drug Administration (FDA)-approved molecular inhibitor for the systemic therapy of advanced hepatocellular carcinoma (HCC). Aspirin has been studied extensively as an anti-inflammation, cancer preventive and therapeutic agent. However, the potential synergistic therapeutic effects of sorafenib and aspirin on advanced HCC treatment have not been well studied. Drug combination studies and their synergy quantification were performed using the combination index method of Chou-Talalay. The synergistic therapeutic effects of sorafenib and aspirin were evaluated using an orthotopic mouse model of HCC and comprehensive gene profiling analyses were conducted to identify key factors mediating the synergistic therapeutic effects of sorafenib and aspirin. Sorafenib was determined to act synergistically on HCC cells with aspirin in vitro. Using Hep3B and HuH7 HCC cells, it was demonstrated that sorafenib and aspirin acted synergistically to induce apoptosis. Mechanistic studies demonstrated that combining sorafenib and aspirin yielded significant synergistically anti-tumor effects by simultaneously silencing ACSL4 and the induction of GADD45B expression in HCC cells both in vitro and in the orthotopic HCC xenograft mouse model. Importantly, clinical evidence has independently corroborated that survival of HCC patients expressing ACSL4highGADD45Blow was significantly poorer compared to patients with ACSL4lowGADD45Bhigh, thus demonstrating the potential clinical value of combining aspirin and sorafenib for HCC patients expressing ACSL4highGADD45Blow. In conclusion, sorafenib and aspirin provide synergistic therapeutic effects on HCC cells that are achieved through simultaneous silencing of ACSL4 and induction of GADD45B expression. Targeting HCC with ACSL4highGADD45Blow expression with aspirin and sorafenib could provide potential synergistic therapeutic benefits.

Human mesenchymal stem cells preferentially migrate toward highly oncogenic human hepatocellular carcinoma cells with activated EpCAM signaling.

The epithelial cell adhesion molecule (EpCAM) is a type I transmembrane glycoprotein that is regarded as one of the markers for tumor initiating cells (TIC) in human hepatocellular carcinoma (HCC). Much work has been directed towards targeting these TICs as a mean of placing these master regulators of cell proliferation and drug resistance under control. Human bone marrow-derived mesenchymal stem cells are known to exhibit an innate property of tumor tropism. However, the possible relationship between MSC and TIC is not well understood. In this study, we show that MSC migration to HCC can be effectively inhibited by TACE and γ-secretase inhibitors that stop the activation of EpCAM signaling event. Silencing of EpCAM expression through siRNA and antibody approaches also resulted in impaired MSC migration. By contrast, increase levels of EpICD proteins in HCC cells and HCC mouse xenografts resulted in enhanced MSC migration. Taken together, these findings show that MSC is drawn to the more oncogenic population of HCC, and could potentially serve as a cell-based carrier of therapeutic genes to target EpICD-enriched hepatic tumor cells.

Atypical regulators of Wnt/ß-catenin signaling as potential therapeutic targets in Hepatocellular Carcinoma.

Hepatocellular carcinoma is one of the most common causes of cancer-related death worldwide. Hepatocellular carcinoma development depends on the inhibition and activation of multiple vital pathways, including the Wnt signaling pathway. The Wnt/ß-catenin pathway lies at the center of various signaling pathways that regulate embryonic development, tissue homeostasis and cancers. Activation of the Wnt/ß-catenin pathway has been observed frequently in hepatocellular carcinoma. However, activating mutations in ß-catenin, Axin and Adenomatous Polyposis Coli only contribute to a portion of the Wnt signaling hyper-activation observed in hepatocellular carcinoma. Therefore, besides mutations in the canonical Wnt components, there must be additional atypical regulation or regulators during Wnt signaling activation that promote liver carcinogenesis. In this mini-review, we have tried to summarize some of these well-established factors and to highlight some recently identified novel factors in the Wnt/ß-catenin signaling pathway in hepatocellular carcinoma. Impact statement Early recurrence of human hepatocellular carcinoma (HCC) is a frequent cause of poor survival after potentially curative liver resection. Among the deregulated signaling cascades in HCC, evidence indicates that alterations in the Wnt/ß-catenin signaling pathway play key roles in hepatocarcinogenesis. In this review, we summarize the potential molecular mechanisms how the microtubule-associated Protein regulator of cytokinesis 1 (PRC1), a direct Wnt signaling target previously identified in our laboratory to be up-regulated in HCC, in promoting cancer proliferation, stemness, metastasis and tumorigenesis through a complex regulatory circuitry of Wnt3a activities.

MELK is an oncogenic kinase essential for early hepatocellular carcinoma recurrence.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. Many kinases have been found to be intimately involved in oncogenesis and the deregulation of kinase function has emerged as a major mechanism by which cancer cells evade normal physiological constraints on growth and survival. Previously, we have performed gene expression profile analysis on HCC samples and have identified a host of kinases that are remarkably overexpressed in HCC. Among these, the Maternal Embryonic Leucine Zipper Kinase (MELK) is highly overexpressed in HCC and its overexpression strongly correlates with early recurrence and poor patients' survival. Silencing MELK inhibited cell growth, invasion, stemness and tumorigenicity of HCC cells by inducing apoptosis and mitosis. We further showed that the overexpression of MELK in HCC samples strongly correlated with the cell cycle- and mitosis-related genes which are directly regulated as part of the forkhead transcription factor FoxM1-related cell division program. Together, our data establish MELK as an oncogenic kinase involved in the pathogenesis and recurrence of HCC and could provide a promising molecular target to develop therapeutic strategies for patients with advanced HCC.

Telomerase reverse transcriptase promotes cancer cell proliferation by augmenting tRNA expression.

Transcriptional reactivation of telomerase reverse transcriptase (TERT) reconstitutes telomerase activity in the majority of human cancers. Here, we found that ectopic TERT expression increases cell proliferation, while acute reductions in TERT levels lead to a dramatic loss of proliferation without any change in telomere length, suggesting that the effects of TERT could be telomere independent. We observed that TERT determines the growth rate of cancer cells by directly regulating global protein synthesis independently of its catalytic activity. Genome-wide TERT binding across 5 cancer cell lines and 2 embryonic stem cell lines revealed that endogenous TERT, driven by mutant promoters or oncogenes, directly associates with the RNA polymerase III (pol III) subunit RPC32 and enhances its recruitment to chromatin, resulting in increased RNA pol III occupancy and tRNA expression in cancers. TERT-deficient mice displayed marked delays in polyomavirus middle T oncogene-induced (PyMT-induced) mammary tumorigenesis, increased survival, and reductions in tRNA levels. Ectopic expression of either RPC32 or TERT restored tRNA levels and proliferation defects in TERT-depleted cells. Finally, we determined that levels of TERT and tRNA correlated in breast and liver cancer samples. Together, these data suggest the existence of a unifying mechanism by which TERT enhances translation in cells to regulate cancer cell proliferation.

Single-layer MoS2 nanosheet grafted upconversion nanoparticles for near-infrared fluorescence imaging-guided deep tissue cancer phototherapy.

A multifunctional nanostructure is prepared by covalently grafting upconversion nanoparticles (UCNPs) with chitosan functionalized MoS2 (MoS2-CS) and folic acid (FA) and then loading phthalocyanine (ZnPc) on the surface of MoS2, which integrates photodynamic therapy (PDT) with photothermal therapy (PTT) and upconversion luminescence imaging into one system for enhanced antitumor efficiency.

The microtubule-associated protein PRC1 promotes early recurrence of hepatocellular carcinoma in association with the Wnt/ß-catenin signalling pathway.

OBJECTIVES: Hepatocellular carcinoma (HCC) is the second leading cause of cancer mortality worldwide. Alterations in microtubule-associated proteins (MAPs) have been observed in HCC. However, the mechanisms underlying these alterations remain poorly understood. Our aim was to study the roles of the MAP protein regulator of cytokinesis 1 (PRC1) in hepatocarcinogenesis and early HCC recurrence. DESIGN: PRC1 expression in HCC samples was evaluated by microarray, immunoblotting and immunohistochemistry analysis. Molecular and cellular techniques including siRNA-mediated and lentiviral vector-mediated knockdown were used to elucidate the functions and mechanisms of PRC1. RESULTS: PRC1 expression was associated with early HCC recurrence and poor patient outcome. In HCC, PRC1 exerted an oncogenic effect by promoting cancer proliferation, stemness, metastasis and tumourigenesis. We further demonstrated that the expression and distribution of PRC1 is dynamically regulated by Wnt3a signalling. PRC1 knockdown impaired transcription factor (TCF) transcriptional activity, decreased Wnt target expression and reduced nuclear ß-catenin levels. Mechanistically, PRC1 interacts with the ß-catenin destruction complex, regulates Wnt3a-induced membrane sequestration of this destruction complex, inhibits adenomatous polyposis coli (APC) stability and promotes ß-catenin release from the APC complex. In vivo, high PRC1 expression correlated with nuclear ß-catenin and Wnt target expression. PRC1 acted as a master regulator of a set of 48 previously identified Wnt-regulated recurrence-associated genes (WRRAGs) in HCC. Thus, PRC1 controlled the expression and function of WRRAGs such as FANCI, SPC25, KIF11 and KIF23 via Wnt signalling. CONCLUSIONS: We identified PRC1 as a novel Wnt target that functions in a positive feedback loop that reinforces Wnt signalling to promote early HCC recurrence.

EDIL3 is a novel regulator of epithelial-mesenchymal transition controlling early recurrence of hepatocellular carcinoma.

BACKGROUND & AIMS: Patients with advanced hepatocellular carcinoma (HCC) continue to have a dismal prognosis. Early recurrence, metastases and angiogenesis are the major obstacles to improve the outcome of HCC. Epithelial-mesenchymal transition (EMT) is a key contributor to cancer metastasis and recurrence, which are the major obstacles to improve prognosis of HCC. METHODS: Combining gene expression profiles of HCC samples with or without early recurrence and established cell lines with epithelial or mesenchymal phenotype, EDIL3 was identified as a novel regulator of EMT. The expression of EDIL3 was evaluated by quantitative PCR, Western blotting or immunohistochemistry. The effects of EDIL3 on the angiogenesis and metastasis of HCC cells were examined by wound healing, Matrigel invasion and tube formation assay in vitro and orthotopic xenograft mouse model of HCC in vivo. The signaling pathways of EDIL3 mediated were investigated through microarray and Western blotting analysis. RESULTS: EDIL3 was identified as a novel regulator of EMT, which contributes to angiogenesis, metastasis and recurrence of HCC. EDIL3 induces EMT and promotes HCC migration, invasion and angiogenesis in vitro. Mechanistically, overexpression of EDIL3, which was regulated by the downregulation of miR-137 in HCC, triggered the activation of ERK and TGF-ß signaling through interactions with αvß3 integrin. Blocking ERK and TGF-ß signaling overcomes EDIL3 induced angiogenesis and invasion. Using the orthotopic xenograft mouse model of HCC, we demonstrated that EDIL3 enhanced the tumorigenic, metastatic and angiogenesis potential of HCC in vivo. CONCLUSIONS: EDIL3-mediated activation of TGF-ß and ERK signaling could provide therapeutic implications for HCC.

The over-expression of survivin enhances the chemotherapeutic efficacy of YM155 in human hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. The inability of chemotherapeutic drugs to selectively target HCC tumor cells because of their predominant resistant phenotype to most conventional anticancer agents bestows a major obstacle for the clinical management of HCC. In this report, we have examined and demonstrated the remarkable heterogeneity of expression of survivin and its phosphorylated active form (p-survivin) in HCC patients' tissues and cell lines. Furthermore, the expression of survivin and p-survivin in HCC cell lines was found to be associated with response to the small-molecule survivin suppressant YM155. Therefore, in the HCC cell lines that express elevated level of survivin and p-survivin, YM155 efficiently inhibited their proliferation, induced cell cycle arrest and apoptosis resulting in DNA damage through the dysregulation of cell-cycle checkpoint-related regulatory genes. Importantly, YM155 yielded significantly better therapeutic effect than sorafenib when tested in an orthotopic mouse model using patient-derived HCC xenografts with elevated survivin and p-survivin expression. Our results clearly demonstrated that the level of survivin and p-survivin expression could serve as molecular predictive biomarkers to select potential YM155-responsive patients, in a move towards delivering precision medicine for HCC patients.

Ascochlorin, an isoprenoid antibiotic inhibits growth and invasion of hepatocellular carcinoma by targeting STAT3 signaling cascade through the induction of PIAS3.

Deregulated activation of oncogenic transcription factors such as signal transducer and activator of transcription 3 (STAT3) plays a pivotal role in proliferation and survival of hepatocellular carcinoma (HCC). Thus, agents which can inhibit STAT3 activation may have an enormous potential for treatment of HCC patients. Hence, in the present report, we investigated the effect of ascochlorin (ASC), an isoprenoid antibiotic on STAT3 activation cascade in various HCC cell lines and orthotopic mouse model. We observed that ASC could substantially inhibit both constitutive and IL-6/EGF inducible STAT3 activation as well as reduce its DNA binding ability. ASC increased the expression of protein inhibitor of activated STAT3 (PIAS3) which could bind to STAT3 DNA binding domain and thereby down-regulate STAT3 activation. Deletion of PIAS3 gene by siRNA abolished the ability of ASC to inhibit STAT3 activation and induce apoptosis in HCC cells. ASC also modulated the expression of diverse STAT3-regulated oncogenic gene products. Finally, when administered intraperitoneally, ASC also inhibited tumor growth in an orthotopic HCC mouse model and reduced STAT3 activation in tumor tissues. Overall our results indicate that ASC mediates its anti-tumor effects predominantly through the suppression of STAT3 signaling cascade, and can form the basis of novel therapy for HCC patients.

ECT2 regulates the Rho/ERK signalling axis to promote early recurrence in human hepatocellular carcinoma.

BACKGROUND & AIMS: Early recurrence is the major obstacle for improving the outcome of patients with hepatocellular carcinoma (HCC). Therefore, identifying key molecules contributing to early HCC recurrence can enable the development of novel therapeutic strategies for the clinical management of HCC. Epithelial cell transforming sequence 2 (ECT2) has been implicated in human cancers, but its function in HCC is largely unknown. METHODS: ECT2 expression was studied by microarrays, immunoblotting and immunohistochemistry in human HCC samples. siRNA- and lentiviral vector-mediated knockdown were employed to decipher the molecular functions of ECT2. RESULTS: The upregulation of ECT2 is significantly associated with early recurrent HCC disease and poor survival. Knockdown of ECT2 markedly suppressed Rho GTPases activities, enhanced apoptosis, attenuated oncogenicity and reduced the metastatic ability of HCC cells. Moreover, knockdown of ECT2 or Rho also suppressed ERK activation, while the silencing of Rho or ERK led to a marked reduction in cell migration. Stable knockdown of ECT2 in vivo resulted in significant retardation of tumour growth and the suppression of ERK activation. High expression of ECT2 correlates with high ERK phosphorylation and poor survival of HCC patients. Furthermore, ECT2 enhances the expression and stability of RACGAP1, accelerating ECT2-mediated Rho activation to promote metastasis. CONCLUSIONS: ECT2 is closely associated with the activation of the Rho/ERK signalling axis to promote early HCC recurrence. In addition, ECT2 can crosstalk with RACGAP1 to catalyse the GTP exchange involved in Rho signalling to further regulate tumour initiation and metastasis.

An oncogenic role of Agrin in regulating focal adhesion integrity in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths globally. The identity and role of cell surface molecules driving complex biological events leading to HCC progression are poorly understood, hence representing major lacunae in HCC therapies. Here, combining SILAC quantitative proteomics and biochemical approaches, we uncover a critical oncogenic role of Agrin, which is overexpressed and secreted in HCC. Agrin enhances cellular proliferation, migration and oncogenic signalling. Mechanistically, Agrin's extracellular matrix sensor activity provides oncogenic cues to regulate Arp2/3-dependent ruffling, invadopodia formation and epithelial-mesenchymal transition through sustained focal adhesion integrity that drives liver tumorigenesis. Furthermore, Agrin signalling through Lrp4-muscle-specific tyrosine kinase (MuSK) forms a critical oncogenic axis. Importantly, antibodies targeting Agrin reduced oncogenic signalling and tumour growth in vivo. Together, we demonstrate that Agrin is frequently upregulated and important for oncogenic property of HCC, and is an attractive target for antibody therapy.