Tumor Suppressor Gene In Hepatocellular Carcinoma Research Articles

Diagnostic and prognostic role of LINC01767 in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a primary contributor to cancer-related mortality on a global scale. However, the underlying molecular mechanisms are still poorly understood. Long noncoding RNAs are emerging markers for HCC diagnosis, prognosis, and therapeutic target. No study of LINC01767 in HCC was published. To conduct a multi-omics analysis to explore the roles of LINC01767 in HCC for the first time. DESeq2 Package was used to analyze different gene expressions. Receiver operating characteristic curves assessed the diagnostic performance. Kaplan-Meier univariate and Cox multivariate analyses were used to perform survival analysis. The least absolute shrinkage and selection operator (LASSO)-Cox was used to identify the prediction model. Subsequent to the validation of LINC01767 expression in HCC fresh frozen tissues through quantitative real time polymerase chain reaction, next generation sequencing was performed following LINC01767 over expression (GSE243371), and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes/Gene Set Enrichment Analysis/ingenuity pathway analysis was carried out. In vitro experiment in Huh7 cell was carried out. LINC01767 was down-regulated in HCC with a log fold change = 1.575 and was positively correlated with the cancer stemness. LINC01767 was a good diagnostic marker with area under the curve (AUC) [0.801, 95% confidence interval (CI): 0.751-0.852, P = 0.0106] and an independent predictor for overall survival (OS) with hazard ratio = 1.899 (95%CI: 1.01-3.58, P = 0.048). LINC01767 nomogram model showed a satisfied performance. The top-ranked regulatory network analysis of LINC01767 showed the regulation of genes participating various pathways. LASSO regression identified the 9-genes model showing a more satisfied performance than 5-genes model to predict the OS with AUC > 0.75. LINC01767 was down-expressed obviously in tumor than para-tumor tissues in our cohort as well as in cancer cell line; the over expression of LINC01767 inhibit cell proliferation and clone formation of Huh7 in vitro. LINC01767 was an important tumor suppressor gene in HCC with good diagnostic and prognostic performance.

Methylation-regulated tumor suppressor gene PDE7B promotes HCC invasion and metastasis through the PI3K/AKT signaling pathway.

Hepatocellular carcinoma (HCC) has a high mortality rate, and the mechanisms underlying tumor development and progression remain unclear. However, inactivated tumor suppressor genes might play key roles. DNA methylation is a critical regulatory mechanism for inactivating tumor suppressor genes in HCC. Therefore, this study investigated methylation-related tumor suppressors in HCC to identify potential biomarkers and therapeutic targets. We assessed genome-wide DNA methylation in HCC using whole genome bisulfite sequencing (WGBS) and RNA sequencing, respectively, and identified the differential expression of methylation-related genes, and finally screened phosphodiesterase 7B (PDE7B) for the study. The correlation between PDE7B expression and clinical features was then assessed. We then analyzed the changes of PDE7B expression in HCC cells before and after DNA methyltransferase inhibitor treatment by MassArray nucleic acid mass spectrometry. Furthermore, HCC cell lines overexpressing PDE7B were constructed to investigate its effect on HCC cell function. Finally, GO and KEGG were applied for the enrichment analysis of PDE7B-related pathways, and their effects on the expression of pathway proteins and EMT-related factors in HCC cells were preliminarily explored. HCC exhibited a genome-wide hypomethylation pattern. We screened 713 hypomethylated and 362 hypermethylated mCG regions in HCC and adjacent normal tissues. GO analysis showed that the main molecular functions of hypermethylation and hypomethylation were "DNA-binding transcriptional activator activity" and "structural component of ribosomes", respectively, whereas KEGG analysis showed that they were enriched in "bile secretion" and "Ras-associated protein-1 (Rap1) signaling pathway", respectively. PDE7B expression was significantly down-regulated in HCC tissues, and this low expression was negatively correlated with recurrence and prognosis of HCC. In addition, DNA methylation regulates PDE7B expression in HCC. On the contrary, overexpression of PDE7B inhibited tumor proliferation and metastasis in vitro. In addition, PDE7B-related genes were mainly enriched in the PI3K/ATK signaling pathway, and PDE7B overexpression inhibited the progression of PI3K/ATK signaling pathway-related proteins and EMT. PDE7B expression in HCC may be regulated by promoter methylation. PDE7B can regulate the EMT process in HCC cells through the PI3K/AKT pathway, which in turn affects HCC metastasis and invasion.

Impact of tumor suppressor genes inactivation on the multidrug resistance phenotype of hepatocellular carcinoma cells

The response of advanced hepatocellular carcinoma (HCC) to pharmacological treatments is unsatisfactory and heterogeneous. Inactivation of tumor suppressor genes (TSGs) by genetic and epigenetic events is frequent in HCC. This study aimed at investigating the impact of frequently altered TSGs on HCC chemoresistance. TSG alterations were screened by in silico analysis of TCGA-LIHC database, and their relationship with survival was investigated. These TSGs were silenced in HCC-derived cell lines using CRISPR/Cas9. TLDA was used to determine the expression of a panel of 94 genes involved in the resistome. Drug sensitivity, cell proliferation, colony formation and cell migration were assessed. The in silico study revealed the down-regulation of frequently inactivated TSGs in HCC (ARID1A, PTEN, CDH1, and the target of p53, CDKN1A). The presence of TP53 and ARID1A variants and the low expression of PTEN and CDH1 correlated with a worse prognosis of HCC patients. In PLC/PRF/5 cells, ARID1A knockout (ARID1AKO) induced increased sensitivity to cisplatin, doxorubicin, and cabozantinib, without affecting other characteristics of malignancy. PTENKO and E-CadKO showed minimal changes in malignancy, resistome, and drug response. In p53KO HepG2 cells, enhanced malignant properties and higher resistance to cisplatin, doxorubicin, sorafenib, and regorafenib were found. This was associated with changes in the resistome. In conclusion, the altered expression and function of several TSGs are involved in the heterogeneity of HCC chemoresistance and other features of malignancy, contributing to the poor prognosis of these patients. Individual identification of pharmacological vulnerabilities is required to select the most appropriate treatment for each patient.

Downregulation of ZC3H13 by miR-362-3p/miR-425-5p is associated with a poor prognosis and adverse outcomes in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is notorious for its poor prognosis. Previous studies identified several N6-methyladenosine (m6A)-related genes that play key roles in the initiation and progression of HCC patients. In particular, the N6-methyladenosine RNA methylation regulator ZC3H13 could be a candidate as a novel biomarker and therapeutic target for hepatocellular carcinoma. In HCC, low expression of ZC3H13 was reported, but the molecular reason is unclear. In this study, we performed pan cancer analysis for ZC3H13 expression and prognosis using The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) data and found that ZC3H13 might be a potential tumor suppressor gene in HCC. Subsequently, miRNAs contributing to ZC3H13 downregulation were identified by a series of in silico analyses, including expression analysis, correlation analysis, and survival analysis. Finally, the miR-362-3p/miR-425-5p-ZC3H13 axis was identified as the most likely upstream miRNA-related pathway of ZC3H13 in HCC. Additionally, miR-362-3p/miR-425-5p mimic and inhibitor results were detected by quantitative real-time PCR (qPCR) analysis and western blotting. We identified an upstream regulatory mechanism of ZC3H13 in HCC, namely, the miR-362-3p/miR-425-5p-ZC3H13 axis. Moreover, the ZC3H13 level was significantly positively associated with tumor immune cell infiltration, biomarkers of immune cells, and immune checkpoint expression. Collectively, our findings elucidated that ncRNA-mediated downregulation of ZC3H13 was correlated with a poor prognosis and tumor immune infiltration in HCC. In conclusion, this study demonstrates that ZC3H13 is a direct target of miR-362-3p/miR-425-5p in liver hepatocellular carcinoma (LIHC) that regulates immune modulation in the microenvironment of LIHC.

Tumor suppressor gene mutations correlate with prognosis and immunotherapy benefit in hepatocellular carcinoma

IntroductionThe tumor microenvironment (TME) has profound impacts on prognosis and immunotherapy. The TME can be altered by the genomic mutations on specific tumor-suppressor genes (TSG), thus, comprehending the association between TME and TSG in hepatocellular carcinoma (HCC) is imperative. MethodsWith a total of 1699 HCC patients from 6 international multicenter cohorts, we delineated the mutational landscape of TSG and summarized the proportion of TSG mutated HCC in different countries. Using the genomic and transcriptomic data, we comprehensively explored the impacts of TSG mutations on TME and immunity in HCC. A dataset of 31 HCC patients from the cBioPortal database was utilized to evaluate the predictive value of TSG subtypes for immunotherapy response. ResultsInterestingly, TSG non-mutated HCC will have more “immune-hot” tumors, and display the infiltration abundance of immune cells such as B cell, CD4+/CD8+T cell, and neutrophil. Moreover, TSG non-mutated HCC was characterized by the higher expression level of three immune checkpoints, including CD40, CD40LG, and TNFRSF4. In line with the TME characterization and immune checkpoint profiles, TSG non-mutated HCC displayed prolonged overall survival and relapse-free survival, notably, are more likely to respond to immune checkpoint inhibitors. ConclusionsOur findings suggested the TSG subtypes could serve as a promising biomarker for guiding surveillance protocol and immunotherapeutic decisions for patients with HCC.

Isotretinoin and Thalidomide Down-Regulate c-MYC Gene Expression and Modify Proteins Associated with Cancer in Hepatic Cells.

Hepatocellular carcinoma (HCC) is the most common form of liver cancer. The number of cases is increasing and the trend for the next few years is not encouraging. HCC is usually detected in the advanced stages of the disease, and pharmacological therapies are not entirely effective. For this reason, it is necessary to search for new therapeutic options. The objective of this work was to evaluate the effect of the drugs isotretinoin and thalidomide on c-MYC expression and cancer-related proteins in an HCC cellular model. The expression of c-MYC was measured using RT-qPCR and western blot assays. In addition, luciferase activity assays were performed for the c-MYC promoters P1 and P2 using recombinant plasmids. Dose-response-time analyses were performed for isotretinoin or thalidomide in cells transfected with the c-MYC promoters. Finally, a proteome profile analysis of cells exposed to these two drugs was performed and the results were validated by western blot. We demonstrated that in HepG2 cells, isotretinoin and thalidomide reduced c-MYC mRNA expression levels, but this decrease in expression was linked to the regulation of P1 and P1-P2 c-MYC promoter activity in isotretinoin only. Thalidomide did not exert any effect on c-MYC promoters. Also, isotretinoin and thalidomide were capable of inducing and repressing proteins associated with cancer. In conclusion, isotretinoin and thalidomide down-regulate c-MYC mRNA expression and this is partially due to P1 or P2 promoter activity, suggesting that these drugs could be promising options for modulating the expression of oncogenes and tumor suppressor genes in HCC.

EYA2 suppresses the progression of hepatocellular carcinoma via SOCS3-mediated blockade of JAK/STAT signaling

BackgroundSomatic mutations are involved in hepatocellular carcinoma (HCC) progression, but the genetic mechanism associated to hepatocarcinogenesis remains poorly understood. We report that Eyes absent homolog 2 (EYA2) suppresses the HCC progression, while EYA2(A510E) mutation identified by exome sequencing attenuates the tumor-inhibiting effect of EYA2.MethodsWhole-exome sequencing was performed on six pairs of human HCC primary tumors and matched adjacent tissues. Focusing on EYA2, expression level of EYA2 in human HCC samples was evaluated by quantitative real-time PCR, western blot and immunohistochemistry. Loss- and gain-of-function studies, hepatocyte-specific deletion of EYA2 (Eya2−/−) in mice and RNA sequencing analysis were used to explore the functional effect and mechanism of EYA2 on HCC cell growth and metastasis. EYA2 methylation status was evaluated using Sequenom MassARRAY and publicly available data analysis.ResultsA new somatic mutation p.Ala510Glu of EYA2 was identified in HCC tissues. The expression of EYA2 was down-regulated in HCC and associated with tumor size (P = 0.001), Barcelona Clinic Liver Cancer stage (P = 0.016) and tumor differentiation (P = 0.048). High level of EYA2 was correlated with a favorable prognosis in HCC patients (P = 0.003). Results from loss-of-function and gain-of-function experiments suggested that knockdown of EYA2 enhanced, while overexpression of EYA2 attenuated, the proliferation, clone formation, invasion, and migration of HCC cells in vitro. Delivery of EYA2 gene had a therapeutic effect on inhibition of orthotopic liver tumor in nude mice. However, EYA2(A510E) mutation led to protein degradation by unfolded protein response, thus weakening the inhibitory function of EYA2. Hepatocyte-specific deletion of EYA2 in mice dramatically promoted diethylnitrosamine-induced HCC development. EYA2 was also down-regulated in HCC by aberrant CpG methylation. Mechanically, EYA2 combined with DACH1 to transcriptionally regulate SOCS3 expression, thus suppressing the progression of HCC via SOCS3-mediated blockade of the JAK/STAT signaling pathway.ConclusionsIn our study, we identified and validated EYA2 as a tumor suppressor gene in HCC, providing a new insight into HCC pathogenesis.

Hypermethylation of MT1G and MT1H CpGs Promoter Sites and High Serum Levels of Cu Affect Survival Rate of Patients Affected by Hepatocellular Carcinoma

Abstract Objectives Recent evidences suggest a principal role of trace elements and metallothioneins (MTs), proteins involved in metal ions homeostasis and detoxification, in hepatocellular carcinogenesis. The study was designed to evaluate whether serum and liver tissue concentrations of the trace elements Cu, Zn and Se are implicated in survival rate of hepatocellular carcinoma (HCC) patients and if promoter DNA methylation is involved in trace elements-related proteins regulation. Methods Cu, Zn and Se levels were determined in serum and liver tissue samples, both HCC and homologous non neoplastic tissue (N) of 27 HCC patients by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Gene expression analysis of MT1G and MT1H, was performed by Real-time qPCR in HCC and N tissue. Promoter DNA methylation of a region overlapping MT1G and MT1H promoters was assessed by bisulfite amplicon sequencing (BSAS) in HCC and N tissues of 23 patients. Kaplan-Meier survival curves were drawn using the log-rank test (Mantel-Cox test) to examine the differences in survival according to serum trace elements and to gene-specific methylation levels. Results Kaplan-Meier analysis according to serum Cu levels showed that subjects within the highest quintile had an increased mortality rate (88.9%) compared with the other four quintiles (P = 0.025). Considering the 80th percentile of Cu levels (1118 μg/L), subjects with Cu concentrations above this value had a significantly decreased survival rate (P < 0.001). Se and Zn content were depleted in HCC tissues as compared to N tissues (P < 0.0001). MT1G and MT1H were strongly repressed in HCC tissues and precisely, MT1H in 24 out of 27 HCC tissues (P = 0.008) and MT1G in 23 out of 27 HCC tissues (P = 0.037). Nine out of 19 HCC tissues showing a down-regulation of MTs with three CpG sites, significantly hypermethylated in HCC tissue as compared to N tissue (P < 0.05). Considering the median methylation level, patients with higher methylation values showed increased mortality rate (P = 0.015). Conclusions The significant repression of MT1G and MT1H in HCC tissue is related to promoter hypermethylation and support the hypothesis of MT1G and MT1H as possible tumor suppressor genes in HCC. The evidence of promoter methylation levels and survival rate association provide new insights for the role of DNA methylation in liver carcinogenesis. Funding Sources N/A.

UBQLN4 promotes progression of HCC via activating wnt-\u03b2-catenin pathway and is regulated by miR-370

BackgroundUbiquilin-4 (UBQLN4) is a member of the ubiquitin–proteasome system that is usually upregulated in many tumor cells. Its overexpression has been associated with poor disease outcomes in various cancer diseases. However, the underlying mechanism of UBQLN4 in the development of hepatocellular carcinoma (HCC) has not been elucidated.MethodsImmunochemistry, real-time PCR, and western blotting were used to evaluate the expression levels of UBQLN4 in cancer tissues. Univariate, Cox-regression, and Kaplan–Meier analyses were performed to determine the association between UBQLN4 expression and HCC prognosis. Cell Counting Kit-8 (CCK-8), transwell, EDU and colony formation assays were conducted to evaluate the role of UBQLN4 in HCC cell progression. The gene set enrichment analysis and luciferase reporter experiments were conducted to find the mechanism of UBQLN4 in HCC.ResultsUbiquilin-4 (UBQLN4) was overexpressed in HCC tissues. Besides, overexpression of UBQLN4 was associated with poor overall survival and disease-free survival rate of HCC patients. The loss-of-function analysis revealed that suppression of UBQLN4 inhibited the proliferation and invasion of HCC cells in vivo and in vitro. The KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis showed that UBQLN4 could regulate activation of the wnt-β-catenin pathway in HCC cells. Furthermore, our results showed that UBQLN4 was downregulated by miR-370, which acted as a tumor suppressor gene in HCC progression.ConclusionThe results of the present study suggest that the miR-370/UBQLN4 axis may play a critical role in the progression of HCC. These findings may inform future strategies for the development of therapeutic agents against HCC.

MiR-455 Inhibits HepG2 Cell Proliferation and Promotes Apoptosis by Targeting RhoC

Hepatocellular carcinoma (HCC) is a common malignancy worldwide with poor prognosis and high mortality. The aberrant expression or alteration of microRNAs (miRNAs) contributes to the development and progression of cancer. Studies have shown that miR-455 plays a regulatory role in the development of HCC. Therefore, in the present study, the role of miR-455 was analyzed in HepG2 cells proliferation and apoptosis using MTT and flow cytometry methods. Binding sites were predicted by bioinformatics and luciferase assay was used to verify the target relationship between miR-455 and RhoC-encoding gene RHOC. After that, the effects of miR-455 on RHOC and its product RhoC, were explored by qPCR and Western blotting. As PTEN is a key tumor suppressor gene in HCC, and Bcl-2 and Caspase 3 are important indication of apoptosis, expression levels of PTEN, Bcl2 and Caspase 3 proteins were determined in cells overexpressing RhoC. We show that miR-455 promotes HepG2 cells apoptosis and inhibits proliferation. Bioinformatics analysis and luciferase assay indicate that specific recognition sites for miR-455 are within the RhoC 3'-UTR. Luciferase activity was significantly lower in the cells co-transfected with miR-455 mimics and RhoC-WT (p < 0.01) as compared to that in control cells, pointing that RHOC gene is, indeed, targeted by miR-455. RHOC mRNA was significantly reduced after miR-455 transfection in HepG2 cells. In addition, we show that RhoC could activate the HCC cells proliferation ability and inhibit apoptosis rate (p < 0.01), and decrease expression of PTEN and Caspase 3 (p < 0.01), while upregulating levels of Bcl2. In conclusion, our study indicates that miR-455 plays a suppressive role in HCC development by targeting RhoC-encoding mRNA.

MiR-486-5p Suppresses Proliferation and Migration of Hepatocellular Carcinoma Cells through Downregulation of the E3 Ubiquitin Ligase CBL.

MicroRNAs have been broadly implicated in cancer, but precise functions and mechanisms in carcinogenesis vary among cancer types and in many cases remain poorly understood. Hepatocellular carcinoma (HCC) is among the most frequent and lethal cancers. The aim of the present study was to investigate the role of miR-486-5p in HCC and identify its specific target. MiR-486-5p was significantly downregulated in HCC tissues and cell lines compared with noncancerous tissues and, respectively, although expression level was not correlated with the degree of infiltration or tumor stage. However, miR-486-5p overexpression in HCC cells inhibited proliferation and migration as evidenced by CCK-8 cell counting, wound healing, and transwell assays, indicating that miR-486-5p is an HCC suppressor. We employed four miRNA databases to predict the target genes of miR-486-5p and verified retrieved genes using qPCR and western blotting. The E3 ubiquitin ligase CBL was significantly downregulated by miR-486-5p overexpression in HCC cell lines at both mRNA and protein level, and overexpression of CBL counteracted the inhibitory effects of miR-486-5p on HCC cell proliferation and migration. Moreover, CBL expression was negatively correlated with miR-486-5p expression in HCC tissues. Collectively, our results suggest that miR-486-5p may act as a tumor suppressor gene in HCC by downregulating CBL expression.

Epigenomic profiling of DNA methylation for hepatocellular carcinoma diagnosis and prognosis prediction.

DNA hypermethylation has emerged as a novel molecular biomarker for the diagnosis and prognosis prediction of many cancers. We aimed to identify clinically useful biomarkers regulated by DNA methylation in hepatocellular carcinoma (HCC). Genome-wide methylation analysis in HCCs and paired noncancerous tissues was performed using an Illumina Infinium HumanMethylation 450K BeadChip array. Methylation-specific polymerase chain reaction and pyrosequencing were used to validate the methylation status of selected genes in 100 paired HCCs and noncancerous samples. A total of 97027 (20.0%) out of 485577 CpG sites significantly were differed between HCC and noncancerous tissues. Among all the significant CpG sites, 48.8% are hypermethylated and 51.2% are hypomethylated in HCCs. Multiple signaling pathways (AMP-activated protein kinase, estrogen, and adipocytokine) involved in gene methylation were identified in HCC. FES was selected for further analysis based on its high level of methylation confirmed by polymerase chain reaction and pyrosequencing. The result showed that FES hypermethylation was correlated with tumor size (0.001), serum alpha fetoprotein (0.023), and tumor differentiation (0.006). FES protein was significantly downregulated in 51/100 (51%) HCCs, and 94.12% (48/51) of them were due to promoter hypermethylation. Both FES hypermethylation and protein downregulation were associated with the progression-free survival and overall survival of HCC patients. Overexpressed and knockdown of FES confirmed its inhibitory effect on the proliferation and migration of HCC cells. We identified many new differentially methylated CpGs in HCCs and demonstrate that FES functions as a tumor suppressor gene in HCC and its methylation status could be used as an indicator for prognosis of HCC.

KLF4-Mediated CDH3 Upregulation Suppresses Human Hepatoma Cell Growth and Migration via GSK-3β Signaling.

P-cadherin (CDH3), a classical cell adhesion molecule involved in tissue integrity and cell localization, has been implicated in many types of cancer. However, little is known about its function and regulatory mechanism in hepatocellular carcinoma (HCC). Here we report that CDH3 was positively regulated by kr¨uppel-like transcription factor 4 (KLF4), which is a crucial tumor suppressor gene in HCC, at mRNA level in HCC cell lines. Luciferase reporter assay and chromatin immunoprecipitation assay indicated that KLF4 directly bound to CDH3 promoter and transcriptionally activated CDH3 expression. Consistently, CDH3 expression was closely related with KLF4 expression in patients' samples and both proteins exhibited a downregulated expression pattern in cancer samples. Functionally, enforced CDH3 expression suppressed and silenced CDH3 expression promoted HCC cell growth and migration in vitro. Mechanistically, we observed that GSK-3β was regulated by CDH3 and may function as a possible downstream effector of CDH3. Knockdown of GSK-3β showed a similar phenotype with CDH3 silencing. Taken together, these findings establish the KLF4/CDH3/GSK-3β axis as an important regulatory mechanism in HCC development.

Downregulation of microRNA-143 promotes cell proliferation by regulating PKCε in hepatocellular carcinoma cells.

The abnormal expression of microRNAs (miRNAs) has been reported in hepatocellular carcinoma (HCC), however, the functional role of miR‑143 in HCC remains to be fully elucidated. The present study aimed to investigate the effects of the downregulation of miR‑143 on HCC cell proliferation and apoptosis, and elucidated the underlying mechanism. Hepg2 and Hep3B human hepatoma cell lines cells were transfected with miR‑143 inhibitor. Following transfection, the cell viability and apoptosis were respectively determined using a 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2‑H‑tetrazolium bromide assay and flow cytometry, and the mRNA and protein levels of protein kinase Cε (PKCε) were examined. The expression levels of PKCε were downregulated by short hairpin (sh)RNA, and the effects of the downregulation of miR‑143 on HCC cell proliferation were measured. The results showed that the miR‑143 inhibitor significantly promoted cell proliferation and suppressed apoptosis in the Hepg2 and Hep3B cells. The miR‑143 inhibitor significantly increased the protein levels of PKCε in the Hepg2 and Hep3B cells; however, no significant differences were found in the mRNA levels of PKCε. In addition, the downregulation of PKCε markedly decreased the cell viability of the Hepg2 and Hep3B cells, and co‑transfection with the miR‑143 inhibitor and PKCε shRNA significantly alleviated the miR‑143 inhibitor‑induced high cell proliferation. Taken together, these results suggested that miR‑143 acts as a tumor suppressor gene in HCC. The downregulation of mi‑143 promoted cell proliferation by regulating PKCε in the HCC cells.

Abstract 1548: Down-regulation of 4-hydroxyphenylpyruvate dioxygenate (HPD) contributes to the pathogenesis of hepatocellular carcinoma (HCC) through ERK / BCL-2 signalling activation

Abstract Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies in the world. Metastasis, recurrence and therapy resistance remain major obstacles to the improvement of long-term survival and represent major causative factors contributing to the rising mortality rates and poor prognosis of HCC. Identification of key drivers important for clinical prognostic utility and elucidation of mechanisms involved in hepatocarcinogenesis is urgently needed to aid in the development of novel treatment modalities. To this end, we began our study with an analysis of a publicly gene expression dataset (GSE14520) comprising of transcriptomic profiles from a large cohort of human non-tumor liver and HCC clinical samples in hope to establish a prognostic gene signature associated with metastatic risk / recurrence status so to identify novel driver genes responsible for HCC development and progression. By this method, 4-hydroxyphenylpyruvate dioxygenase (HPD) was identified as a candidate tumor suppressor gene in HCC. HPD was found to be frequently down-regulated in primary HCC tumors as compared with peri-tumor liver tissues. Its expression negatively correlated with aggressive HCC pathological features, including tumor stage, metastasis, recurrence and survival. Notably, down-regulated HPD expression in HCC is in part a result of hypermethylation at the HPD promoter. The functional effect of HPD was then examined in HCC cells with or without HPD stably repressed or ectopically overexpressed. Upon knockdown of HPD, HCC cells displayed significantly enhanced abilities to form tumors, metastasize and confer sorafenib resistance in vitro and in vivo. Conversely, overexpression of HPD in HCC cells led to an opposing effect. Consistently, sorafenib-resistant HCC patient derived xenografts also displayed attenuated levels of HPD as compared with parental sorafenib-sensitive counterparts. Mechanistically, HPD down-regulation mediates aggressive cancer features in HCC through activation of an ERK and BCL-2 pro-survival signaling pathway, as evidenced by rescue experiments involving the ERK inhibitor U0126. Collectively, our findings suggest HPD down-regulation in HCC tumors to promote tumorigenicity, metastasis and sorafenib resistance through ERK / BCL-2 signaling activation and that HPD may represent a novel prognostic biomarker for HCC. Citation Format: Man Tong, Tin Lok Wong, Steve Tin-Chi Luk, Noélia Che, Kai Yau Wong, Tsun Ming Fung, Xin-Yuan Guan, Nikki P Lee, Yun-Fei Yuan, Terence K Lee, Stephanie Ma. Down-regulation of 4-hydroxyphenylpyruvate dioxygenate (HPD) contributes to the pathogenesis of hepatocellular carcinoma (HCC) through ERK / BCL-2 signalling activation [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 1548. doi:10.1158/1538-7445.AM2017-1548

LINC00052 upregulates EPB41L3 to inhibit migration and invasion of hepatocellular carcinoma by binding miR-452-5p.

Numerous studies have demonstrated that a class of long noncoding RNAs (lncRNAs) are dysregulated in hepatocellular carcinoma (HCC) and they are closely related with tumorigenesis. Our previous studies indicated that LINC00052 was a downregulated lncRNA in HCC and acted as a tumor suppressor gene. Using transcription microarray analysis, we found that knockdown of LINC00052 resulted in EPB41L3 downregulation. However, the function of EPB41L3 and the mechanism of LINC00052 downregulating EPB41L3 in HCC remain unclear. In this study, we found that overexpression of LINC00052 could upregulate the EPB41L3 expression and it might serve as a tumor suppressor gene in HCC. Database analysis showed that miR-452-5P could target LINC00052. The binding regions between LINC00052 and miR-452-5P were confirmed by luciferase assays. Moreover, LINC00052 inhibited cell malignant behavior by increasing miR-452-5P expression, suggesting that LINC00052 was negatively regulated by miR-452-5P. In addition, overexpression of miR-452-5P resulted in a decrease of EPB41L3 expression, suggesting that EPB41L3 was as a target of miR-452-5P. In conclusion, these results demonstrated that a novel pathway was mediated by LINC00052 in HCC.

Pivotal roles of glycogen synthase-3 in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world, and represents the second most frequently cancer and third most common cause of death from cancer worldwide. At advanced stage, HCC is a highly aggressive tumor with a poor prognosis and with very limited response to common therapies. Therefore, there is still the need for new effective and well-tolerated therapeutic strategies. Molecular-targeted therapies hold promise for HCC treatment. One promising molecular target is the multifunctional serine/threonine kinase glycogen synthase kinase 3 (GSK-3). The roles of GSK-3β in HCC remain controversial, several studies suggested a possible role of GSK-3β as a tumor suppressor gene in HCC, whereas, other studies indicate that GSK-3β is a potential therapeutic target for this neoplasia. In this review, we will focus on the different roles that GSK-3 plays in HCC and its interaction with signaling pathways implicated in the pathogenesis of HCC, such as Insulin-like Growth Factor (IGF), Notch, Wnt/β-catenin, Hedgehog (HH), and TGF-β pathways. In addition, the pivotal roles of GSK3 in epithelial-mesenchymal transition (EMT), invasion and metastasis will be also discussed.

Abstract B28: Discovery of 2-acetylpyridine-[N-(3-hydroxy-2-naphthoyl)]hydrazone analogs as glycine N-methyltransferase (GNMT) inducers for the treatment of hepatocellular carcinoma (HCC)

Abstract Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the third most common cause of cancer mortality. Because of the late diagnosis, poor treatment options and high recurrence, the incidence still nearly equals to the mortality rate. Therefore, the discovery of novel therapeutic agents and/or drug combination strategies is urgently needed. Glycine N-methyltransferase (GNMT) is a tumor suppressor gene for HCC. Literatures revealed that the expression of GNMT is significantly down-regulated in HCC patients. Therefore, discovery of small molecule compounds that are able to enhance GNMT expression will have important implications for the treatment of HCC. Recently, we have identified a small molecule, 2-acetylpyridine-[N-(3-hydroxy-2-naphthoyl)]hydrazone (1), as a hit from a collective drug library containing more than 20,000 compounds using a GNMT gene expression-oriented screen platform. Preliminary results indicated that compound 1 is capable of inducing GNMT expression strongly with 7.57 folds to control in 2.5 micromole. In order to discover novel lead compounds based on the initial hit, we have synthesized more than 100 analogs of compound 1 and evaluated for their effects on GNMT promoter activity. Results indicated certain newly synthesized compounds are more active than compound 1. A comprehensive Structure-activity relationships (SAR) study will be presented. Citation Format: Cherng-Chyi Tzeng, Chih-Hua Tseng, Yeh-Long Chen. Discovery of 2-acetylpyridine-[N-(3-hydroxy-2-naphthoyl)]hydrazone analogs as glycine N-methyltransferase (GNMT) inducers for the treatment of hepatocellular carcinoma (HCC). [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B28.

Expression and Significances of G-Protein-Coupled Receptor Kinase 3 in Hepatocellular Carcinoma.

Objective: To investigate expression, clinical, pathologic and prognostic significances of G-protein-coupled receptor kinase 3 (GRK3) in hepatocellular carcinoma (HCC).Materials and Methods: Expression of GRK3 was detected using Western blotting and tissue microarray-based immunohistochemical staining in 8 and 395 patients (training set: n=164; validation set: n=231) with HCC underwent hepatectomy, respectively. GRK3 expression and its associations with cliniopathologic variables and tumor-specific survival were evaluated.Results: Expression of GRK3 was lower in tumor than in non-tumor tissues from 4 out of 8 patients. In the training set, the H-score of tumoral GRK3 staining was much lower than that in adjacent non-tumor liver tissues. In addition, GRK3 was associated with tumor-node-metastasis (TNM) stage and serum α-fetoprotein (AFP) level. Patients with high GRK3 tumors were found to carry significantly better tumor-specific survival, compared with those with low GRK3 ones. Furthermore, GRK3 was identified as one of independent predictors of favorable prognosis, adjusted for clinicopathologic parameters. Importantly, these results were further validated in the independent validation set. In all patients and 7 out of 10 subgroups, GRK3 was also revealed to be prognostic.Conclusions: GRK3 is down-regulated and predicts good prognosis in HCC. Therefore, GRK3 might function as a tumor suppressor gene in HCC.

AKR7A3 suppresses tumorigenicity and chemoresistance in hepatocellular carcinoma through attenuation of ERK, c-Jun and NF-κB signaling pathways.

Hepatocellular carcinoma (HCC), which accounts for 85–90% of primary liver cancer, is now the second leading cause of cancer-related mortality worldwide. Here we reported that Aldo-Keto Reductase family 7A isoform 3 (AKR7A3) is frequently down-regulated in HCC, associating with poor overall survival rate, elevated serum α-fetoprotein (AFP) and poor differentiation of HCC. The promoter region of AKR7A3 was detected to be hypermethylated. Loss of heterozygosity (LOH) was also detected in AKR7A3. Functional assays on both AKR7A3 overexpressed and knockdown cells, including foci formation, colony formation in soft agar, migration, invasion and tumor formation in nude mice, demonstrated the strong tumor suppressive functions of AKR7A3. In addition, treatment of chemotherapy drug cisplatin showed that AKR7A3 sensitizes tumor cells to apoptosis. Mechanistically, western blot analysis showed that overexpression of AKR7A3 inhibits the activation of ERK, c-Jun and NF-κB. In summary, we found that AKR7A3 functions as a tumor suppressor gene in HCC through attenuating c-Jun, ERK and NF-κB signaling pathways.