Metastatic Potential Of Hepatocellular Carcinoma Cells Research Articles

NUCB2 promotes hepatocellular carcinoma cell growth and metastasis by activating the E2F4/PTGR1 axis.

Background: The important role of nucleobindin 2 (NUCB2) in various cancers has been recently recognized. However, its biological functions and regulatory mechanisms in hepatocellular carcinoma (HCC) remain unclear. Methods: The expression level of NUCB2 in HCC was assessed using public databases, immunohistochemistry, and Western blotting. The effects of NUCB2 on cell proliferation and metastasis were investigated using colony formation, EdU, Transwell assays, and an in vivo mouse xenograft model. Regulation of E2F4 by NUCB2 was identified by protein half-life and in vivo ubiquitylation assays. The relationship between E2F4 and prostaglandin reductase 1 (PTGR1) was investigated by qRT-PCR, RT-PCR, and chromatin immunoprecipitation assays. Results: This study found that NUCB2 expression was significantly higher in HCC tissues than in normal liver tissues, and patients with high expression displayed shorter survival rates. Inhibition of NUCB2 reduced the proliferation and metastatic potential of HCC cells in vitro and in vivo. NUCB2 depletion reduced PTGR1 expression, which reduced cell proliferation and migration. Our findings suggested that NUCB2 suppressed E2F4 degradation by interacting with E2F4. Additionally, increased E2F4 levels facilitated PTGR1 transcription by directly binding to the PTGR1 promoter. Conclusion: This study demonstrated the oncogenic properties of NUCB2 in HCC and suggested that NUCB2 facilitates hepatocellular carcinoma progression by activating the E2F4/PTGR1 axis.

IGFBP2 drives epithelial-mesenchymal transition in hepatocellular carcinoma via activating the Wnt/β-catenin pathway

Metastasis has emerged as a major impediment to achieve successful therapeutic outcomes in hepatocellular carcinoma (HCC). Nonetheless, the intricate molecular mechanisms governing the progression of HCC remain elusive. Herein, we present evidence highlighting the influence exerted by insulin-like growth factor-binding protein 2 (IGFBP2) as a potent oncogene driving the malignant phenotype. Our investigation reveals a marked elevation of IGFBP2 expression in primary tumors, concomitant with the presence of mesenchymal biomarkers in HCC. Through in vitro and in vivo experimentation, we demonstrate that the overexpression of IGFBP2 expedites the progression of epithelial-mesenchymal transition (EMT) and facilitates the metastatic potential of HCC cells, chiefly mediated by the Wnt/β-catenin signaling pathway. Notably, knockdown of IGFBP2 significantly decreased the expression of total and nuclear β-catenin, N-cadherin and vimentin in the treatment of the specific activator of Wnt/β-catenin CHIR-99021. Collectively, our findings identify IGFBP2 as a pivotal regulator within the HCC EMT axis, whereby its overexpression confers the distinctly aggressive clinical features characteristic of the disease.

EZH2-mediated epigenetic silencing of tumor-suppressive let-7c/miR-99a cluster by hepatitis B virus X antigen enhances hepatocellular carcinoma progression and metastasis

BackgroundHepatitis B virus (HBV)-encoded X antigen, HBx, assists in the development of hepatocellular carcinoma (HCC) through complex mechanisms. Our results provide new insights into the EZH2 epigenetic repression of let-7c that promotes HCC migration induced by HBx. Thus, let-7c and HMGA2 represent key diagnostic markers and potential therapeutic targets for the treatment of HBV-related HCC.ResultsWe investigated the epigenetic regulation of let-7c, an important representative miRNA in liver tumor metastasis, in human HCC cells to verify the effect of HBx. Based on quantitative PCR (qPCR) of mRNA isolated from tumor and adjacent non-tumor liver tissues of 24 patients with HBV-related HCC, EZH2 expression was significantly overexpressed in most HCC tissues (87.5%). We executed a miRNA microarray analysis in paired HBV-related HCC tumor and adjacent non-tumorous liver tissue from six of these patients and identified let-7c, miR-199a-3p, and miR-99a as being downregulated in the tumor tissue. Real-time PCR analysis verified significant downregulation of let-7c and miR-99a in both HepG2X and Hep3BX cells, which stably overexpress HBx, relative to parental cells. HBX enhanced EZH2 expression and attenuated let-7c expression to induce HMGA2 expression in the HCC cells. Knockdown of HMGA2 significantly downregulated the metastatic potential of HCC cells induced by HBx.ConclusionsThe deregulation of let-7c expression by HBx may indicate a potential novel pathway through deregulating cell metastasis and imply that HMGA2 might be used as a new prognostic marker and/or as an effective therapeutic target for HCC.

CDK9 inhibitors downregulate DKK1 expression to suppress the metastatic potential of HCC cells.

Elevated expression of Dickkopf-1 (DKK1) is frequently observed in hepatocellular carcinoma (HCC) patients with poor clinical outcomes. Several reports indicating the functional involvement of DKK1 in HCC progression have suggested DKK1 as a promising therapeutic target for HCC. In this study, to develop an efficient way to target DKK1, we assessed the effect of CDK9 inhibitors on DKK1 expression linked to metastatic movement of HCC. The expression of DKK1 in CDK9 inhibitor-treated HCC cells was measured by western blot, ELISA and quantitative real-time reverse transcription PCR. Wound healing assay, migration assay, invasion assay and western blot were examined to evaluate the functional role of DKK1 in CDK9 inhibitors-treated HCC. Inactivation of CDK9 either by a catalytic inhibitor being clinically evaluated or by a specific CDK9 protein degrader largely downregulated DKK1 expression at the transcript and protein levels. In addition, CDK9 inhibitors suppressed the migration and invasion of HCC cells. We observed that ectopic high expression of DKK1 at least partially reversed the defects in metastatic movement of HCC cells mediated by CDK9 inhibitors. We further discovered that the DKK1-nuclear β-catenin axis associated with the metastatic potential of HCC cells was impaired by CDK9 inhibitors. Taken together, our findings suggest that CDK9 inhibitors are potent tools to target DKK1, which can suppress the metastatic progression of HCC.

Folic acid depletion along with inhibition of the PERK arm of endoplasmic reticulum stress pathway promotes a less aggressive phenotype of hepatocellular carcinoma cells.

Folate is a vital vitamin involved in one-carbon metabolism and any changes in folate status may lead to epigenetic alterations. It is already known that stages and liver cancer progression are negatively correlated with folate levels. Nevertheless, mechanisms involved in folate deficiency in HCC (Hepatocellular carcinoma) are still not completely understood. So, this study tests the hypothesis that due to the increased demand for ER (endoplasmic reticulum) proteins, folate deficiency might lead to the induction of UPR (unfolded protein response), which is further correlated with HCC outcomes. HCC cells were cultured in both folate normal (FN) and folate deficient (FD) conditions and the expression of genes of ER stress pathway was investigated. The results demonstrated activation of UPR via induction of PERK, ATF4, and LAMP3. Besides this, FD reduced the migratory capacity and the invasiveness of HCC cells along with the reduction in mesenchymal markers like vimentin but increased apoptosis. Treatment with GSK2606414 (PERK inhibitor) decreased the FD induced expression of PERK, ATF4, and LAMP3 in FD cells. Also, GSK2606414 was found to increase apoptotic cell death and to further reduce the cancer hallmarks selectively in FD cells butnot in FN cells. Altogether, our data suggest that targeting the ER stress pathway along with folate deficiency may provide a more promising elimination of the metastatic potential of HCC cells contributing to more effective therapeutic agents.

Protein Tyrosine Kinase 7 (PTK7) Promotes Metastasis in Hepatocellular Carcinoma via SOX9 Regulation and TGF-β Signaling

Metastasis is found in most advanced hepatocellular carcinoma (HCC) patients, and it drives tumor recurrence and systemic failure. There is no effective treatment owing to its complex biological features. Many of the molecular drivers of metastasis are crucial players in normal physiology but behave unconventionally during cancer progression. Targeting these molecular drivers for therapy and differentiating them from a physiological background require a detailed examination of the novel mechanisms involved in their activation during metastasis. Publicly available transcriptomic data such as that of TCGA-LIHC and Gene Expression Omnibus were utilized to identify novel targets upregulated in advanced and metastatic HCC. Validation of candidates was assisted by immunohistochemistry performed on tissue microarrays derived from more than 100 HCC patients. Expression of protein tyrosine kinase 7 (PTK7) was studied under the treatment of transforming growth factor-β1 and knockdown of SRY-Box Transcription Factor 9 (SOX9) to delineate upstream regulation, while CRISPR-mediated knockout and lentiviral overexpression of PTK7 in HCC cells were performed to study their functional and signaling consequences. Manipulated HCC cells were injected into mice models either by orthotopic or tail-vein injection to observe for any in vivo pro-metastatic effects. PTK7 was discovered to be the kinase most significantly upregulated in advanced and metastatic HCC, at both transcriptomic and proteomic level. Bioinformatic analyses and functional assays performed in HCC cell lines revealed transforming growth factor-β signaling and SOX9 to be important activators of PTK7 expression. Functionally, enrichment of PTK7 expression could positively regulate metastatic potential of HCC cells in vitro and in lung metastasis models performed in immunodeficient mice. The up-regulation of PTK7 recruited the epithelial-mesenchymal transition components, zinc finger protein SNAI2 (SLUG) and zinc finger E-box-binding homeobox 1 (ZEB1). Our study proposes PTK7 as a novel molecular driver in metastatic HCC, particularly in a transforming growth factor-β-activated microenvironment. The preferential expression of PTK7 resulted in a previously unobserved regulatory effect on the recruitment of epithelial-mesenchymal transition components, which established PTK7 as a potential determinant of specific epithelial-mesenchymal transition status. Therefore, our data support the continual development of PTK7-targeted agents as antimetastatic therapies.

LncRNA AC099850.3 promotes hepatocellular carcinoma proliferation and invasion through PRR11/PI3K/AKT axis and is associated with patients prognosis.

Background: LncRNA is a key factor influencing tumor development. The present study aimed to investigate the effect of a novel lncRNA on the progression of hepatocellular carcinoma (HCC).Methods: A candidate lncRNA in The Cancer Genome Atlas database was identified using limma and survival R packages. The effect of lncRNA AC099850.3 on cell proliferation, apoptosis, migration, and invasion, as well as its association with immune cells in HCC were investigated. Furthermore, the functional mechanisms of lncRNA AC099850.3 in HCC were elucidated.Results: The aberrant expression of lncRNA AC099850.3 was identified in tumor tissues and its prognostic relevance in HCC was determined. The results revealed that AC099850.3 was highly expressed in HCC tissues and cell lines, and it predicted poor prognosis in patients with HCC. Furthermore, knockdown of AC099850.3 significantly suppressed the proliferation and metastatic potential of HCC cells, and promoted cell apoptosis in HCC cells. The results of gene set enrichment analysis revealed that the PI3K/AKT pathway was associated with the biological function of AC099850.3, which was further validated by western blotting. PRR11 was identified as the target gene of AC099850.3 and we established that AC099850.3 acted as an oncogene in the PRR11/PI3K/AKT axis. Immune cell infiltration analyses results revealed that AC099850.3 was positively correlated with T follicular helper cells, M0 macrophages, CD4+ memory T cells, and memory B cells. Conversely, AC099850.3 was negatively correlated with M2 macrophages, monocytes, natural killer cells, and CD8+ T cells, which could be responsible for its oncogenic effect. Of note, a significantly positive correlation was observed between AC099850.3 and key immune checkpoint molecules (PD-1, PD-L1, PD-L2, and CTLA4) in the present study, making AC099850.3 a potential immune therapeutic target for HCC.Conclusion: AC099850.3 can promote malignant biological behavior of HCC cells, and could be a potential biomarker and therapeutic target for HCC.

Metal-Regulatory Transcription Factor-1 Targeted by miR-148a-3p Is Implicated in Human Hepatocellular Carcinoma Progression.

Metal-regulatory transcription factor-1 (MTF-1) is of importance in maintaining metal homeostasis. Copper exposure considerably stimulates the proliferation of hepatocellular carcinoma (HCC) cells with enhanced MTF-1 expression. However, the underlying molecular mechanisms have not been completely elucidated. In this study, we utilized different approaches to investigate the potential role of MTF-1 involved in HCC progression. The expression levels of MTF-1 and miR-148a-3p were determined using real-time polymerase chain reaction (PCR), Western blotting, and immunohistochemistry. The interaction of MTF-1 with apurinic apyrimidinic endonuclease/redox effector factor 1 (APE/Ref-1) or miR-148a-3p was determined using immunoprecipitation or dual-luciferase reporter assay, respectively. Cell viability and metastatic ability were evaluated using colony formation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound scratch, and Transwell assays, and apoptotic cells were detected by flow cytometry. The biological functions of MTF-1 and miR-148a-3p were also determined using a xenograft mouse model. MTF-1 expression was upregulated in HCC cells and was associated with poor survival and recurrence. MTF-1 overexpression enhanced the proliferation and metastatic potential of HCC cells. Further mechanistic analyses demonstrated that MTF-1 bound to APE/Ref-1 and that MTF-1 is a direct target of miR-148-3p, which inversely regulated MTF-1 transcription activity. MiR-148a-3p overexpression effectively inhibited HCC cell proliferation and metastasis stimulated by MTF-1, with increased apoptosis. There was a decrease in miR-148a-3p expression in exosomes isolated from the plasma of patients with HCC and HCC cell culture supernatants. Co-incubation of HCC cells with exosomes from hepatocyte-conditioned media inhibited cell migration and caused apoptosis. The in vivo study revealed slow growth of MTF-1-knockdown and miR-148a-3p-overexpressing Hep3B-derived xenografts, with reduced tumor volume and weight compared with the control group. Collectively, these findings implicate MTF-1 as a modulator of HCC tumorigenesis and progression. Selective targeting towards exosomal miR-148a-3p, which might contribute to the negative regulation of MTF-1 at least partially in HCC, demonstrates therapeutic benefits for patients with HCC.

GPCR48 promotes invasion and metastasis by inducing epithelial-mesenchymal transition in hepatocellular carcinoma cells

Objective: To observe the G protein-coupled receptor 48 (GPCR48) expression in hepatocellular carcinoma (HCC) cell lines with different metastatic potential and its characteristics effect on the invasion and metastasis of Huh7 hepatoma cells via epithelial-mesenchymal transition (EMT). Methods: Western blot was used to detect the protein expression level of GPCR48 in HCC cells with different metastatic potential. The lentivirus vector expressing GPCR48 gene was constructed. GPCR48 was overexpressed in Huh7 hepatoma cells. The GPCR48 overexpression level was detected by real-time PCR and Western blot. Transwell invasion and migration assay was used to detect the Huh7 hepatoma cells invasion and migration ability in the Control, Mock and GPCR48 overexpression group. Real-time PCR and Western blot were used to detect Huh7 hepatoma cells mRNA and protein expression levels of the EMT related markers (E-cadherin, N-cadherin, vimentin, and γ catenin) in the Control, Mock and GPCR48 overexpression groups, respectively. Analysis of variance was used to compare the differences between data sets. Results: GPCR48 protein expression level in metastatic HCC cell lines was significantly higher than non-metastatic HCC cell lines (P < 0.05). The lentivirus vector expressing the GPCR48 gene had effectively transfected the Huh7 hepatoma cells and stably expressed the GPCR48mRNA and protein. Compared with the Mock and the Control group, Huh7 hepatoma cells invasion and migration ability in the GPCR48 overexpression group was significantly enhanced (F≥5.54, P < 0.05), and the mRNA and protein expression levels of epithelial phenotypic markers E-cadherin and γ-catenin were decreased (P < 0.05). The mRNA and protein expression levels of the mesenchymal phenotypic markers N-cadherin and Vimentin were increased (P < 0.05), indicating that EMT changes occurred in Huh7 hepatoma cells had overexpressed GPCR48. Conclusion: GPCR48 expression level is positively correlated with the metastatic potential of HCC cells. GPCR48 overexpression can down-regulate the expression of epithelial phenotypic markers and up-regulate the expression of mesenchymal phenotypic markers, and induce EMT changes in HCC cells, thus promoting HCC cells invasion and migration.

The application of whole exome sequencing in different metastatic potential of heptaocellular carcinoma

Objective Genome-wide exome sequencing was used to analyze DNA of hepatocellular carcinoma (HCC) tissues and cell lines with different metastatic potentials to explore the mutation genes and sites related to the HCC metastasis. Methods Genomic DNA extracted from twelve HCC tumors and its adjacent tissues and six HCC cells (HCC-LM3, MHCC-97L, MHCC-97H, HepG2, SMCC-7721 and PLC-RFP-5) with different metastatic potentials were analyzed by whole exome sequencing. Bioinformatics analysis and screening of mutations was used to investigated mutation genes and sites potentially associated with HCC metastasis. Results Comparing high and low metastatic potential HCC, high metastatic potential HCC group had more than three gene mutations including UIMC1 (rs3733876 C/T), SEMA3C (rs1527482 G/A), SAMD9 (rs10279499 G/T), RECK (rs16932912 G/A), PDLIM4 (rs4877 G/T, LIMK2 (rs3747154 A/G), CRIM1 (rs3821169 G/T) which was associated with HCC metastasis. Mutate genes and its sites such as CAPZB (rs79308175C/T), CSF1R (rs10079250A/G), HSPA5 (rs143920039A/T), SORBS3 (rs2449331T/C, rs3758036C/T) only occured in high metastatic potential HCC cells (HCC-LM3, MHCC-97L and MHCC-97H), while mutation sites RASAL3 (rs146624357G/A, rs142945276 C/T) only appeared in three low metastatic potential cells (HepG2, SMCC-7721 and PLC-RFP-5). The DNA comparative analysis of three homologous high metastatic potential HCC cell lines (HCC-LM3, MHCC-97Land MHCC-97H) showed that only EHBP1 (rs77403174T/C) was presented in HCC-LM3, while FAM189B (rs150296362C/T), SERPINB13 (rs144903442G/A) and ARHGEF1 (rs2303797C/T) only presented in MHCC-97L and MHCC-97H. Conclusion Mutations and its sites such as UIMC1 (rs3733876C/T), SEMA3C (rs1527482G/A), SAMD9 (rs10279499G/T) was detected to potentially related to the HCC metastasis by genome-wide exome sequencing. Key words: Whole exome sequencing; Hepatocellular carcinoma; Mutations; Metastasis

Mining featured biomarkers associated with vascular invasion in HCC by bioinformatics analysis with TCGA RNA sequencing data

This study aims to identify the feature genes associated with vascular invasion in hepatocellular carcinoma (HCC). Here, the RNA sequencing data related to vascular invasion in The Cancer Genome Atlas (TCGA) database, including 292 HCC patients with complete clinical data were included in our study as the training dataset for construction and E-TABM-36, including 41 HCC patients with complete clinical data was used as the validation dataset. Following data normalization, differentially expressed mRNA and copy number (CN) were selected between with and without vascular invasion samples. A support vector machine (SVM) classifier was constructed and validated in GSE9828 and GSE20017 datasets. Total 59 feature genes were found by the SVM classifier. Using Cox regression analysis, three clinical features, including Patholigic T, Stage and vascular invasion and 6 optimal prognostic genes, including ANO1, EPHX2, GFRA1, OLFM2, SERPINA10 and TKT were significantly correlated with prognosis. A risk score formula was developed to assess the prognostic value of 6 optimal prognostic genes, which were identified to possess the most remarkable correlation with overall survival in HCC patients. By performing in vitro experiments, we observed TKT was significantly increased, but OLFM2 was decreased in high metastatic potential HCC cell lines (SK-HEP-1 and MHCC-97 H) compared with low metastatic potential cell line Huh7 and normal human liver cell line LO2 using western blotting analysis. Knockdown of TKT in MHCC-97H or overexpression of OLFM2 in SK-HEP-1 significantly suppressed cell migration and invasion using transwell assays. Our results demonstrated that TKT and OLFM2 might be novel independent biomarkers for predicting survival based on the presence of vascular invasion in patients with HCC.

HDAC6 Suppresses Let-7i-5p to Elicit TSP1/CD47-Mediated Anti-Tumorigenesis and Phagocytosis of Hepatocellular Carcinoma.

Histone deacetylase 6 (HDAC6) uniquely serves as a tumor suppressor in hepatocellular carcinogenesis, but the underlying mechanisms leading to tumor suppression are not fully understood. To identify comprehensive microRNAs (miRNAs) regulated by HDAC6 in hepatocellular carcinogenesis, differential miRNA expression analysis of HDAC6-transfected Hep3B cells was performed. Using integrative analyses of publicly available transcriptome data and miRNA target prediction, we selected five candidate miRNAs and, through in vitro functional validation, showed that let-7i-5p specifically suppressed thrombospondin-1 (TSP1) in hepatocellular carcinoma (HCC). Ectopic expression of antisense let-7i-5p (AS-let-7i-5p) inhibited in vitro tumorigenesis of HCC cells. In addition, treatments of partially purified TSP1 from culture cell media (ppTSP1) and recombinant TSP1 (rTSP1) exhibited similar effects with AS-let-7i-5p treatment on the same HCC cells, whereas TSP1 neutralizing antibody treatment significantly attenuated these effects. Notably, treatments of HDAC6 plasmid, AS-let-7i-5p, ppTSP1, and rTSP1 significantly suppressed in vitro angiogenesis and metastatic potential of HCC cells, but the co-treatment of TSP1 antibody specific to cluster of differentiation 47 (CD47) binding domain successfully blocked these effects in the same cells. Furthermore, we demonstrated that recovery of HDAC6 elicited let-7i-5p suppression to de-repress TSP1 expression; therefore, it occupied the CD47 receptor to block CD47-SIRPα-mediated anti-phagocytosis of macrophage in HCC. We also observed that HCC-derived exosomal let-7i-5p suppressed TSP1 of recipient hepatocyte cells. Treatments of HDAC6 plasmid, AS-let-7i-5p, and rTSP1 suppressed tumor incidence as well as tumor growth rates in a spontaneous mouse HCC model. Conclusion: Our findings suggest that the HDAC6-let-7i-5p-TSP1 regulatory pathway suppresses neoplastic and antiphagocytic behaviors of HCC by interacting with cell surface receptor CD47 in HCC and neighboring cells of tumor microenvironment, providing a therapeutic target for the treatment of liver malignancy and metastasis.

CCL15 Recruits Suppressive Monocytes to Facilitate Immune Escape and Disease Progression in Hepatocellular Carcinoma.

Chemokines play a key role in orchestrating the recruitment and positioning of myeloid cells within the tumor microenvironment. However, the tropism regulation and functions of these cells in hepatocellular carcinoma (HCC) are not completely understood. Herein, by scrutinizing the expression of all chemokines in HCC cell lines and tissues, we found that CCL15 was the most abundantly expressed chemokine in human HCC. Further analyses showed that CCL15 expression was regulated by genetic, epigenetic, and microenvironmental factors, and negatively correlated with patient clinical outcome. In addition to promoting tumor invasion in an autocrine manner, CCL15 specifically recruited CCR1+ cells toward HCC invasive margin, approximately 80% of which were CD14+ monocytes. Clinically, a high density of marginal CCR1+ CD14+ monocytes positively correlated with CCL15 expression and was an independent index for dismal survival. Functionally, these tumor-educated monocytes directly accelerated tumor invasion and metastasis through bursting various pro-tumor factors and activating signal transducer and activator of transcription 1/3, extracellular signal-regulated kinase 1/2, and v-akt murine thymoma viral oncogene homolog signaling in HCC cells. Meanwhile, tumor-derived CCR1+ CD14+ monocytes expressed significantly higher levels of programmed cell death-ligand 1, B7-H3, and T-cell immunoglobulin domain and mucin domain-3 that may lead to immune suppression. Transcriptome sequencing confirmed that tumor-infiltrating CCR1+ CD14+ monocytes were reprogrammed to upregulate immune checkpoints, immune tolerogenic metabolic enzymes (indoleamine and arginase), inflammatory/pro-angiogenic cytokines, matrix remodeling proteases, and inflammatory chemokines. Orthotopic animal models confirmed that CCL15-CCR1 axis forested an inflammatory microenvironment enriched with CCR1+ monocytes and led to increased metastatic potential of HCC cells. Conclusion: A complex tumor-promoting inflammatory microenvironment was shaped by CCL15-CCR1 axis in human HCC. Blockade of CCL15-CCR1 axis in HCC could be an effective anticancer therapy.

T-cell immune regulator 1 enhances metastasis in hepatocellular carcinoma

Recurrence and metastasis are major challenges in the management of hepatocellular carcinoma (HCC) patients after resection. To identify a metastasis-associated gene signature, we performed comparative gene expression analysis with recurrent HCC tissues from HCC patients who underwent partial or total hepatectomy and from non-metastatic primary HCC tissues. From this, we were able to identify genes associated with HCC recurrence. TCIRG1 (T-Cell Immune Regulator 1) was one of the aberrantly overexpressed genes in patients with recurrent HCC who had undergone total hepatectomy. The significant overexpression of TCIRG1 was confirmed using the Liver Hepatocellular Carcinoma dataset from The Cancer Genome Atlas. High expression of TCIRG1 was significantly associated with poor 5-year disease-free and recurrence-free survival of HCC patients. TCIRG1 knockdown suppressed tumor cell growth and proliferation in HCC cell lines; caused a significant increase in the proportion of cells in the G1/S phase of cell cycle; induced cell death; suppressed the metastatic potential of HCC cells by selectively regulating the epithelial–mesenchymal transition (EMT) regulatory proteins E-cadherin, N-cadherin, Fibronectin, Snail and Slug; and significantly attenuated the metastatic potential of ras-transformed NIH-3T3 cells in vitro and in vivo. These findings suggest that TCIRG1 functions as a metastatic enhancer by modulating growth, death and EMT in HCC cells. TCIRG1 could be a therapeutic target for the treatment of liver malignancy and metastasis.

MiR-520f promotes cell aggressiveness by regulating fibroblast growth factor 16 in hepatocellular carcinoma.

Cancer metastasis is a multistep cellular process, which has be confirmed one of mainly causes of cancer associated-death in hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) participate in tumorigenesis function as either tumor suppressor genes or oncogenes. In order to elaborate the critical miRNAs and their targets in HCC, we compared the differential expression of miRNA between HCC tissues and normal tissues. Microarray analysis revealed there were several significantly up-expression miRNAs in HCC, compared to normal solid tissue. Among them, the expression of miR-520f was the most over-expression in HCC cell lines than that in human normal liver cells LO2, as well as up-regulated in HCC than that in the corresponding normal tissues. Moreover, Kaplan Meier-plotter analyses revealed that higher miR-520f levels were negatively correlated with poor overall survival. By applying bioinformatics methods to identify the targeting genes of miRNA, we demonstrated that fibroblast growth factor 16 (FGF16) was the miR-520f-targeted gene. Meanwhile, FGF16 exhibited similar expression patterns to miR-520f in HCC. Forced miR-520f expression accelerated HCC cells proliferation and aggressiveness in vitro and in vivo, whereas down-regulation of miR-520f caused an opposite outcome. Moreover, over-expression of FGF16 was closely related to the metastatic potential of HCC cells. Herein, we also confirmed that ectopic expression of FGF16 in HCC cells promoted proliferation, colony formation, and increased migration, invasion of HCC cells in vitro. Collectively, our results indicated that over-expression of miR-520f and FGF16 was positively associated with aggressive phenotypes and poor survival of patients with HCC, and miR-520f promoted HCC aggressive phenotypes by regulating the expression of FGF16. MiR-520f may be employed as a prognostic factor and therapeutic target for HCC.

WWC2 is an independent prognostic factor and prevents invasion via Hippo signalling in hepatocellular carcinoma.

WWC family proteins negatively regulate HEK293 cell proliferation and organ growth by suppressing the transcriptional activity of Yes‐associated protein (YAP), a major effector of the Hippo pathway. The function of the scaffolding protein WWC1 (also called KIBRA) has been intensively studied in cells and animal models. However, the expression and clinicopathologic significance of WWC2 in cancer are poorly characterized. This study aimed to clarify the biological function and mechanism of action of WWC2 in hepatocellular carcinoma (HCC). Retrospective analysis revealed WWC2 was significantly down‐regulated in 95 clinical HCC tissues compared to the paired adjacent non‐cancerous tissues. Moreover, loss of WWC2 expression was significantly associated with advanced clinicopathological features, including venous infiltration, larger tumour size and advanced TNM stage. Positive WWC2 expression was associated with significantly better 5‐year overall survival, and WWC2 was an independent prognostic factor for overall survival in HCC. Moreover, we confirmed WWC2 inhibits HCC cell invasive ability in vitro. Elevated YAP expression was also observed in the same cohort of HCC tissues. Pearson's correlation coefficient analysis indicated WWC2 expression correlated inversely with nuclear YAP protein expression in HCC. Mechanistically, we confirmed overexpression of WWC2 suppresses the invasive and metastatic potential of HCC cells by activating large tumour suppressor 1 and 2 kinases (LATS1/2), which in turn phosphorylates the transcriptional co‐activator YAP. Overall, this study indicates WWC2 functions as a tumour suppressor by negatively regulating the Hippo signalling pathway and may serve as a prognostic marker in HCC.

Abstract 3829: TCIRG1, T-cell immune regulator 1, functions as a metastatic enhancing gene in liver tumorigenesis

Abstract Recurrence and metastasis are a major challenge in the management of hepatocellular carcinoma (HCC) patients after HCC resection. In order to identify metastatic molecular signature, we performed comparative gene expression profiling analysis with recurred HCC tissues from HCC patients who underwent partial or total hepatectomy and non-metastatic primary HCC. From this, we were able to recapitulate molecular signatures associate with HCC recurrence, and found that TCIRG1 (T-Cell Immune Regulator 1) was one of the aberrantly overexpressed gene elements in recurred HCC patients with total hepatectomy. We then observed that TCIRG1 is significantly overexpressed in TCGA-LIHC (Liver Hepatocellular Carcinoma Dataset of The Cancer Genome Atlas), and high expression of TCIRG1 was significantly associated with poor prognosis of HCC patients in 5-year disease-free. TCIRG1 knockdown suppressed tumor cell growth and proliferation in Huh7 and SNU475, liver cancer cell lines. From flow cytometric analysis for cell cycle analysis and cell death, we observed that TCIRG1 knockdown caused a significant increase of G1/S phase, and also induced programmed cell death processing in liver cancer cells. TCIRG1 knockdown also reduced the metastatic potential of HCC cells by selectively regulating epithelial-mesenchymal transition (EMT) regulatory proteins, E-cadherin, N-cadherin, Vimentin, Fibronectin, Snail and Slug, in liver cancer cells. In addition, sustained expression of TCIRG1 in liver cancer cell line reduced tumor growth rate in mouse xenograft model. Moreover, targeted-disruption of TCIRG1 significantly attenuated the metastatic potential of ras-transformed NIH-3T3 cells in vitro and in vivo. In conclusion, our findings suggest that TCIRG1 functions as metastatic enhancing gene by modulating cellular growth, death, and EMT in liver cancer cells providing TCIRG1 as a therapeutic target for the treatment of liver malignancy and metastasis. Citation Format: Hee Doo Yang, Jung Woo Eun, Qingyu Shen, Hyung Seok Kim, Sang Yean Kim, Suk Woo Nam. TCIRG1, T-cell immune regulator 1, functions as a metastatic enhancing gene in liver tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3829. doi:10.1158/1538-7445.AM2017-3829

Novel role of semaphorin 3A in the growth and progression of hepatocellular carcinoma

Semaphorin3A(SEMA3A), a secretory protein, is a founding member of the semaphorin family and functions in both the biological behavior of tumor cells and the modulation of tumor-associated macrophages. However, the role of SEMA3A in hepatocellular carcinoma(HCC) is still not well established. In the present study, we investigated the expression levels of SEMA3A in 80HCC tissues and cell lines, using RT-qPCR, western blotting and immunohistochemistry. Expression profile analysis revealed that SEMA3A was significantly overexpressed in human HCC patients and positively correlated with the metastatic potential of HCC cells. Lentiviral transfection into PLC/PRF/5 and HCCLM3 cells was performed to stably upregulate and downregulate the expression of SEMA3A in HCC cells. Cell Counting Kit-8(CCK-8), wound-healing and invasion assays revealed that SEMA3A promoted the proliferation and migration of HCC cells invitro. Proteome profiler antibody microarray analysis revealed that overexpression of SEMA3A in HCC cells induced a significant increase in the expression levels of gelsolin-like capping protein(CapG), galectin-3, enolase2 and epithelial cell adhesion molecule(EpCAM). Furthermore, the upregulation of SEMA3A in HCC cells promoted tumor growth and progression in an HCC mouse model. These results indicate that SEMA3A enhances CapG, galectin-3, enolase2 and EpCAM expression to promote HCC progression and is a potential therapeutic target for HCC.

Identification of ACTG2 functions as a promoter gene in hepatocellular carcinoma cells migration and tumor metastasis

Metastatic hepatocellular carcinoma (HCC) remains a mostly incurable disease. The fact that the identity of the mechanisms that regulate metastasis in HCC is known hampers the development of anti-metastatic therapies. Currently, there is no effective treatment for HCC once it is progressed to metastatic stage. Therefore, further study to elucidate the molecular mechanism underlying the metastasis of HCC is urgently required for the improvement of HCC treatment. Here, we describes actin gamma smooth muscle 2 (ACTG2) over-express in HCC and demonstrates high-expression of ACTG2 as a promising therapeutic target in HCC metastasis. The use of shRNA to knock-down ACTG2 impaired cells migration and invasion in vitro. Moreover, silencing of ACTG2 causes almost complete inhibition of metastasis in vivo. In contrast, overexpression ACTG2 significantly enforces HCC cells migration and metastasis. Finally, ACTG2 boosts the metastatic potential of HCC cells in a Notch homolog 1 (Notch1) dependent manner. Collectively, our study reveals a critical role of ACTG2 in HCC tumor metastasis, and renders it a novel target for the treatment of HCC.

Oncogenic potential of histone-variant H2A.Z.1 and its regulatory role in cell cycle and epithelial-mesenchymal transition in liver cancer

H2A.Z is a highly conserved H2A variant, and two distinct H2A.Z isoforms, H2A.Z.1 and H2A.Z.2, have been identified as products of two non-allelic genes, H2AFZ and H2AFV. H2A.Z has been reported to be overexpressed in breast, prostate and bladder cancers, but most studies did not clearly distinguish between isoforms. One recent study reported a unique role for the H2A.Z isoform H2A.Z.2 as a driver of malignant melanoma. Here we first report that H2A.Z.1 plays a pivotal role in the liver tumorigenesis by selectively regulating key molecules in cell cycle and epithelial-mesenchymal transition (EMT). H2AFZ expression was significantly overexpressed in a large cohort of hepatocellular carcinoma (HCC) patients, and high expression of H2AFZ was significantly associated with their poor prognosis. H2A.Z.1 overexpression was demonstrated in a subset of human HCC and cell lines. H2A.Z.1 knockdown suppressed HCC cell growth by transcriptional deregulation of cell cycle proteins and caused apoptotic cell death of HCC cells. We also observed that H2A.Z.1 knockdown reduced the metastatic potential of HCC cells by selectively modulating epithelial-mesenchymal transition regulatory proteins such as E-cadherin and fibronectin. In addition, H2A.Z.1 knockdown reduced the in vivo tumor growth rate in a mouse xenograft model. In conclusion, our findings suggest the oncogenic potential of H2A.Z.1 in liver tumorigenesis and that it plays established role in accelerating cell cycle transition and EMT during hepatocarcinogenesis. This makes H2A.Z.1 a promising target in liver cancer therapy.