Therapeutic Target In HCC Research Articles

DDX17 promotes hepatocellular carcinoma progression via inhibiting Klf4 transcriptional activity

DEAD box RNA helicase 17 (DDX17) is a transcriptional regulator of several transcription factors, which is more appreciated than its role in RNA metabolism. However, prognostic value and biofunction of DDX17 in HCC remain unclear. Illuminating the mechanism underlying the regulating HCC progression by DDX17 may contribute to therapeutic strategies. In our study, we report for the first time that DDX17 was overexpressed in HCC specimens by using The Cancer Genome Atlas (TCGA) and immunohistochemistry (IHC) and correlated to clinical pathological characteristics and patients’ survival. In vitro, DDX17 was ascertained to alter HCC migratory and invasive capacities after overexpression and knockdown in HCC cell lines. Moreover, by performing co-immunoprecipitation (Co-IP) and GST-pull down assay, the physical association between DDX17 and Klf4 was discovered and validated. Additionally, DDX17 could modulate expressions of Klf4 target genes including E-cadherin, MMP2 by inhibiting the promoter activity. The potent correlation between DDX17 and Klf4 target gene expressions was further appraised by a same set of 30 HCC tissues. Besides, we discovered that DDX17 could not deploy its function in regulating Klf4 target gene expressions and HCC progression in Klf4-depletion condition. Intriguingly, DDX17 failed to interact with Klf4 once the zinc-finger domain was deleted and inhibited the binding of Klf4 on MMP-2 promoter. Collectively, our study enucleates novel mechanism of DDX17-mediated oncogenesis by suppressing the transcriptional activity of Klf4 thus is likely to be a therapeutic target in HCC.

Calcium Regulates HCC Proliferation as well as EGFR Recycling/Degradation and Could Be a New Therapeutic Target in HCC.

Calcium is the most abundant element in the human body. Its role is essential in physiological and biochemical processes such as signal transduction from outside to inside the cell between the cells of an organ, as well as the release of neurotransmitters from neurons, muscle contraction, fertilization, bone building, and blood clotting. As a result, intra- and extracellular calcium levels are tightly regulated by the body. The liver is the most specialized organ of the body, as its functions, carried out by hepatocytes, are strongly governed by calcium ions. In this work, we analyze the role of calcium in human hepatoma (HCC) cell lines harboring a wild type form of the Epidermal Growth Factor Receptor (EGFR), particularly its role in proliferation and in EGFR downmodulation. Our results highlight that calcium is involved in the proliferative capability of HCC cells, as its subtraction is responsible for EGFR degradation by proteasome machinery and, as a consequence, for EGFR intracellular signaling downregulation. However, calcium-regulated EGFR signaling is cell line-dependent. In cells responding weakly to the epidermal growth factor (EGF), calcium seems to have an opposite effect on EGFR internalization/degradation mechanisms. These results suggest that besides EGFR, calcium could be a new therapeutic target in HCC.

Multilevel regulation of RUVBL2 expression predicts poor prognosis in hepatocellular carcinoma

BackgroundHepatocellular carcinoma (HCC) is the second-most lethal cancer worldwide with a complex pathogenesis. RuvB-like 2 (RUVBL2) was previously found to contribute to hepatocarcinogenesis. However, its expression, regulation and clinical significance have not been systematically evaluated in a large number of clinical samples.MethodsHere, we performed a comprehensive analysis of RUVBL2 based on multiple datasets from 371 liver cancer patients of The Cancer Genome Atlas (TCGA) and on immunohistochemical staining in 153 subjects. In addition, the aberrant signaling pathways caused by RUVBL2 overexpression were investigated.ResultsWe demonstrated that promoter hypomethylation, copy number gain, MYC amplification and CTNNB1 mutation were all responsible for RUVBL2 overexpression in HCC. High levels of RUVBL2 mRNA were associated with shorter recurrence-free survival time (RFS) but not overall survival time (OS). Furthermore, RUVBL2 protein was overexpressed in the nucleus and cytoplasm of HCC samples. Univariate and multivariate survival analyses showed that strong nuclear and cytoplasmic staining of RUVBL2 independently predicted worse OS and RFS with a 2.03-fold and a 1.71-fold increase in the hazard ratio, respectively. High levels of RUVBL2 promoted carcinogenesis through the heat shock protein 90 (HSP90)-Cell Division Cycle 37 (CDC37), AKT serine/threonine kinase (AKT) and mitogen-activated protein kinase (ERK/MAPK) pathways.ConclusionThe deregulation of RUVBL2 in HCC is influenced at the genomic, epigenetic and transcriptional levels. Our findings highlight the potential roles of RUVBL2 as a promising prognostic marker as well as a therapeutic target for HCC.

Abstract 4878: Prognostic significance of Arginase and CK19 expression in human hepatocellular carcinoma after surgical resection: Correlation with recurrence-free survival

Abstract Background. Arginase-1 is an enzyme that is responsible for the conversion of arginine to urea in the urea cycle. A previous study has shown prognostic value of arginase expression in HCC following surgical resection. However, clear distinction on the role of arginase-1 as a predictor of recurrence in hepatocellular carcinoma remains unanswered. Occasionally, CK19, a cholangiocytic marker can be expressed in HCC, but the combination of arginase-1 and CK19 expression has never been evaluated. In this study, we investigate the usefulness of arginase-1 and CK19 expression alone and in combination in the determination of tumor recurrence following surgical resection in patients with HCC. Design: Formalin-fixed paraffin embedded tissue sections from 112 HCCs were immunostained by an automated method (DAKO enVision + Dual Link System-HRP) using mouse monoclonal Arginase-1 (clone SL6ARG, Dako) and mouse monoclonal CK19 (clone RCK108, invitrogen). Nuclear and/or cytoplasmic reactivity was scored based on the intensity and percentage of positive cells in the tumor cells. Arginase-1 expression was separated into high (intense diffuse or regional positivity in > 50% of tumor cells) and low (weak or negative expression). The clinicopathologic variables including recurrence and survival were obtained from the patients charts and were correlated with the immunochemical results. Results: High arginase-1 expression was detected in 93 patients (83%), whereas CK19 was positive in 19 patients (17%). In the univariate analyses, CK19 positivity (+) in HCC was associated with decreased recurrence free survival when compared with CK19 negative HCC (P=0.001). Arginase-1 expression was not associated recurrence-free and overall survival. However, the combination of arginase-1 and CK19 is associated with decreased recurrence-free survival (p<0.001). Furthermore, Arginase-1/CK19+ combined with TNM staging (p=0.042), vascular invasion (p<0.001) multiple tumor numbers (p=0.02) may play a role as additional predictors of recurrence-free survival. In the multivariate analysis, TNM stage, vascular invasion and CK19 were identified as independent prognostic indicators for recurrence-free survival. In addition, vascular invasion was an independent prognostic predictor of overall survival. Conclusion: The combination of arginase-1 and CK19 immunoreactivity are potential biomarkers of adverse prognosis in HCC, correlating with presence of multiple tumors, vascular invasion and advanced stage. The results of this study may explain why clear beneficial effects of recombinant human arginase have not been demonstrated in clinical studies. Further study of arginase expression and its potential role as a therapeutic target in HCC appear warranted. Citation Format: Ifeyinwa E. Obiorah, Joeffery Chahine, Kyungmin Ko, ByoungUk Park, Jose deGuzman, Bhaskar Kallakury. Prognostic significance of Arginase and CK19 expression in human hepatocellular carcinoma after surgical resection: Correlation with recurrence-free survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4878.

Long Non-Coding RNA RP1130-1 Suppresses Cell Proliferation, Invasion and Migration Mediated by Downregulation of TGF-β

Background: Hepatocellular carcinoma has low levels of long non-coding RNA (LncRNA) RP1130. However, the effects of LncRNA RP1130 in hepatocellular carcinoma still unknown. Materials and Methods: Expression of LncRNA RP1130-1 in HCC and cell lines were detected by real-time PCR. Cell proliferation was assessed by CCK-8. Wound-healing and Transwell assays were performed for HCC cell migration and invasion. Western blotting was carried out to evaluate cell cycle, migration and invasion associated proteins in HCC. Results: Expression levels of LncRNA RP1130-1 was dramatically lower in HCC tissues than in normal control. Similarly, LncRNA RP1130-1 was downregulated in HCC cell lines compared with LO2. The cellular experiments revealed that high expression of LncRNA RP1130-1 in HCC inhibited cell proliferation, migration and invasion. In addition, overexpression of LncRNA RP1130-1 inhibited the expression of transforming growth factor (TGF)-β, and TGF-β reversed the effects of LncRNA RP1130 in HCC cell lines. Conclusions: LncRNA RP1130 exerts anti-tumor effects mediated by inhibiting TGF-β. In summarize, our results indicate that LncRNA RP1130/TGFβ may be a potential therapeutic target for HCC.

H3B-6527 clinical biomarker assay development and characterization of HCC patient samples.

4121 Background: FGFR4/FGF19 signaling axis is a novel therapeutic target in HCC. Multiple covalent FGFR4 inhibitors, including H3B-6527, are under clinical development. Preclinical efficacy studies in mice (including PDX) have shown that FGF19 expression (FGF19+) is a predictive biomarker for FGFR4 inhibitor response. The mechanisms driving FGF19 expression in HCC is largely unknown however, in some cases, focal amplification of ch11q13.3 containing FGF19 gene is thought to drive the FGF19 expression. Consistent with the preclinical observations, clinical studies have also shown that FGF19+is a predictive biomarker for FGFR4 inhibitor response. However, these trials have also reported a large number of FGF19+patients failing to respond to FGFR4 inhibitors necessitating refinement of patient selection strategies. In an attempt to obtain deeper insights into the role of FGF19+as a predictive biomarker and potentially uncover additional biomarkers that will enable improvement in patient selection strategies, we have characterized a set of 258 HCC patient samples Methods: Samples were acquired from biobanks and utilized to qualify clinical assays including FGF19 copy number (FISH), mRNA expression (qRT-PCR), FGF19 protein (IHC), and a focused NGS panel for assessing both mutations and copy number. A multiplexed protein and mRNA platform enabled assessment of p-ERK and Ki67 (protein) and Cyp7A1 (mRNA) amongst other exploratory PD biomarkers from two FFPE slides. Results: FGF19 positivity rates for IHC and qRT-PCR were 18% (41/225) and 42% (87/209), respectively. The overall correlation was 60%, with 63% (22/235) IHC positive cases also being positive by qRT-PCR. For IHC+/qRT-PCR (-) cases, RNA quality may have impacted assay sensitivity. 4% (9/244) of samples were positive for FGF19 copy number. Among samples with FGF19 copy number gains, 22% (2/9) did not show positive FGF19 expression. Conclusions: Based on our data, FGF19 mRNA is a more inclusive selection strategy and offers an approach to further refine thresholds for efficacy as determined in the clinic. Multiplexed protein-mRNA assays were also validated and implemented to enable a more comprehensive clinical biomarker program.

A novel lncRNA MCM3AP-AS1 promotes the growth of hepatocellular carcinoma by targeting miR-194-5p/FOXA1 axis

BackgroundHepatocellular carcinoma (HCC) is the most common malignant liver tumor with poor clinical outcomes. Increasing amount of long non-coding RNAs (lncRNAs) have been revealed to be implicated in the carcinogenesis and progression of HCC. However, the expressions, clinical significances, and roles of most lncRNAs in HCC are still unknown.MethodsThe expression of lncRNA MCM3AP antisense RNA 1 (MCM3AP-AS1) in HCC tissues and cell lines was detected by qRT-PCR and fluorescence in situ hybridization. Immunoblotting, CCK-8, EdU, colony formation and flow cytometry were performed to investigate the role of MCM3AP-AS1 in HCC cell proliferation, cell cycle and apoptosis in vitro. A subcutaneous tumor mouse model was constructed to analyze in vivo growth of HCC cells after MCM3AP-AS1 knockdown. The interactions among MCM3AP-AS1, miR-194-5p and FOXA1 were measured by RNA pull-down, RNA immunoprecipitation and luciferase reporter assay.ResultsWe revealed a novel oncogenic lncRNA MCM3AP-AS1, which is overexpressed in HCC and positively correlated with large tumor size, high tumor grade, advanced tumor stage and poor prognosis of HCC patients. MCM3AP-AS1 knockdown suppressed HCC cell proliferation, colony formation and cell cycle progression, and induced apoptosis in vitro, and depletion of MCM3AP-AS1 inhibited tumor growth of HCC in vivo. Mechanistically, MCM3AP-AS1 directly bound to miR-194-5p and acted as competing endogenous RNA (ceRNA), and subsequently facilitated miR-194-5p’s target gene forkhead box A1 (FOXA1) expression in HCC cells. Interestingly, FOXA1 restoration rescued MCM3AP-AS1 knockdown induced proliferation inhibition, G1 arrest and apoptosis of HCC cells.ConclusionsOur results recognized MCM3AP-AS1 as a novel oncogenic lncRNA, which indicated poor clinical outcomes in patients with HCC. MCM3AP-AS1 exerted an oncogenic role in HCC via targeting miR-194-5p and subsequently promoted FOXA1 expression. Our findings suggested that MCM3AP-AS1 could be a potential prognostic biomarker and therapeutic target for HCC.

LncRNA SNHG16 Promotes Hepatocellular Carcinoma Proliferation, Migration and Invasion by Regulating miR-186 Expression.

Long non-coding RNA (lncRNA) and microRNA (miRNA) play an important role in genesis and progression of tumors. The aim of this study was to explore the expression, biological function and molecular mechanism of small nucleolar RNA host gene 16 (SNHG16) in HCC. RT-qPCR was conducted to evaluate the expression level of SNHG16 in HCC tissues and cell lines. Our findings showed for the first time that SNHG16 was up-regulated in HCC tissues and cell lines. The expression of SNHG16 in cancer tissues was highly correlated with tumor size, TNM stage, ALT expression level and HBV DNA level. Moreover, cell proliferation, migration and invasion were detected by CCK-8 assay, transwell migration assay and transwell invasion assay, respectively. Xenograft tumor experiment was used to determine the biological function of SNHG16 in vivo. As revealed by our data, SNHG16 accelerated the proliferation, migration and invasion of HCC cell. SNHG16 facilitated tumor formation in vivo. Next, the relationship between SNHG16, miR-186 and ROCK1 were analyzed using bioinformatics analysis, qRT-PCR, luciferase reporter assay and western blot. Further molecular mechanism studies reported that the expression of SNHG16 was negatively correlated with the level of miR-186 and SNHG16 directly bound to miR-186. SNHG16 and miR-186 repressed each other. Notably, rescue experiments were conducted and showed that miR-186 reversed the effect of SNHG16 on cell. Taken together, SNHG16 promoted HCC cell proliferation, migration and invasion by functioning as a competitive endogenous RNA (ceRNA) to negatively regulate miR-186 expression. Our data suggested that SNHG16 might be a potential biomarker and a new therapeutic target for HCC.

Abstract 1515: NCOA3 promotes tumor growth by activating telomerase reverse transcriptase and predicts poor prognosis in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is one of the most common cancers and a leading cause of cancer death worldwide. The rising incidence and mortality rate of HCC in most countries are due to an increased rate of chronic Hepatitis C virus infection, alcohol abuse and obesity. The molecular mechanisms leading to the development of HCC are complicated, consist of various genetic and epigenetic changes, and are associated with altered signaling pathways. Among these molecular events, elevated expression of human telomerase reverse transcriptase (TERT) is an important alteration in HCC and a hallmark of human cancers. TERT is highly expressed in HCC and positively correlated with the development of HCC. However, the detailed mechanism of TERT activation in HCC remains largely unclear. Here, we identified nuclear receptor coactivator-3 (NCOA3) as a TERT promoter-binding protein, which specifically bound to the -234~-144 region of the TERT promoter. Overexpression of NCOA3 enhanced TERT promoter activity and expression, and promoted HCC cell growth. Moreover, we demonstrated that NCOA3 interacted with the transcription factor SP1 to promote TERT expression. The clinical data showed that the expression of NCOA3 and TERT were positively correlated and elevated in HCC tissues, and HCC patients with high level of NCOA3/TERT had poor prognosis. Collectively, our study revealed that NCOA3 bound to the TERT promoter and activated TERT expression to promote HCC growth, indicating that the NCOA3/TERT signaling pathway could be a potential therapeutic target for HCC. [Funding support: This work was supported by the funds from the National Natural Science Foundation of China (81772925, 81472178, 81702761), the State “973 Program” of China (2014CB542005), and the Natural Science Foundation of Guangdong Province (2016A03031100, 2015A030313018, 2017A030313615)]. Citation Format: Miao Chen, Wenbin Li, Yixin Li, Changlin Zhang, Ge Qin, Qian Long, Dingbo Shi, Wei Guo, Shuihan Shi, Kefang Zhang, Wuguo Deng. NCOA3 promotes tumor growth by activating telomerase reverse transcriptase and predicts poor prognosis in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1515.

Golgi phosphoprotein 3 (GOLPH3) promotes hepatocellular carcinoma progression by activating mTOR signaling pathway

BackgroundHepatocellular carcinoma (HCC) is the sixth most common cancer and the second leading cause of cancer-related deaths worldwide. Despite new technologies in diagnosis and treatment, the incidence and mortality of HCC continue rising. And its pathogenesis is still unclear. As a highly conserved protein of the Golgi apparatus, Golgi phosphoprotein 3 (GOLPH3) has been shown to be involved in tumorigenesis of HCC. This study aimed to explore the exact oncogenic mechanism of GOLPH3 and provide a novel diagnose biomarker and therapeutic strategy for patients with HCC.MethodsFirstly, the expression of GOLPH3 was detected in the HCC tissue specimens and HCC cell lines. Secondly, RNA interference was used for GOLPH3 gene inhibition. Thirdly, cell proliferation was analyzed by MTT; cell apoptosis was analyzed by Annexin-V/PI staining, Hoechst 33,342 staining and caspase 3/7 activity assay. Fourthly, xenograft tumor model was used to study the function of GOLPH3 in tumor growth in vivo. Finally, western blotting and immunohistochemistry were used to investigate the role of GOLHP3 in the mTOR signaling pathway.ResultsData showed that the mRNA and protein expression of GOLPH3 were up-regulated in HCC tumor tissue and cell lines compared with those of control (P < 0.05). Correlation analyses showed that GOLPH3 expression was positively correlated with serum alpha-fetoprotein level (AFP, P = 0.006). Knockdown GOLPH3 expression inhibited proliferation and promoted apoptosis in HCC cell lines. What’s more, knockdown GOLPH3 expression led to tumor growth restriction in xenograft tumor model. The expression of phosphorylated mTOR, AKT and S6 K1 were significantly higher in HCC tumor tissue and cell lines compared with those in normal liver tissues (p < 0.05). While the phosphorylated mTOR, AKT and S6 K1 were much lower when diminished GOLPH3 expression in HCC cell lines both in vitro and in vivo.ConclusionThe current study suggests that GOLPH3 contributes to the tumorigenesis of HCC by activating mTOR signaling pathway. GOLPH3 is a promising diagnose biomarker and therapeutic target for HCC. Our study may provide a scientific basis for developing effective approaches to treat the HCC patients with GOLPH3 overexpression.

Downregulation of Nedd4L predicts poor prognosis, promotes tumor growth and inhibits MAPK/ERK signal pathway in hepatocellular carcinoma

Accumulating evidence indicates that the neural precursor cell–expressed, developmentally downregulated 4–like (Nedd4L) related with some tumor progression pathways and was found abnormally expressed in several kinds of solid cancers. However, the role and mechanism of Nedd4L in HCC remain unknown. This study was to assess the role of Nedd4L in HCC tumorigenesis and prognosis. The real-time quantitative RT-PCR and immunohistochemistry results revealed that Nedd4L was downregulated in HCC tissues compared to corresponding peri-noncancerous tissue, and HCC patients with low expression of Nedd4L exhibited poor prognosis assessed by Kaplan-Meier and Cox regression analysis in 78 HCC patients. Furthermore, knockdown of Nedd4L could significantly promote proliferation of HCC cells by CCK-8 and colony formation assays in vitro; whereas ectopic expression of Nedd4L resulted in attenuating proliferation in vitro and tumor growth in vivc determined by nude mice xenografts model. Mechanically, Nedd4L could phosphorylate ERK1/2 and regulate genes related with apoptosis. Collectively, Nedd4L plays a tumor suppressive role in HCC, possibly through triggering MAPK/ERK-mediated apoptosis, and Nedd4L downregulation may be a potential prognostic biomarker as well as a therapeutic target for HCC.

TRIP6 promotes cell proliferation in hepatocellular carcinoma via suppression of FOXO3a

Thyroid hormone receptor-interacting protein 6 (TRIP6), a member of LIM family, acts as an adaptor protein and is overexpressed in several tumor types. However, the clinical significance and biological role of TRIP6 in HCC remains unknown. In our study, we found that TRIP6 was markedly overexpressed in HCC cells and clinical specimens compared with normal hepatocytes and adjacent non-tumor tissues. Immunohistochemical and statistical analysis showed that the expression of TRIP6 significantly correlated with HCC patients' clinical stage and poor survival. Moreover, we demonstrated that overexpressing TRIP6 significantly enhanced, whereas silencing endogenous TRIP6 inhibited, the proliferation and the anchorage-independent growth ability of HCC cells. In addition, overexpression of TRIP6 accelerated, while inhibition of TRIP6 retarded, G1-S phase transition in HCC cells. We further found that overexpression of TRIP6 increased the activation of AKT and suppressed the transactivity of FOXO3a. Meanwhile, overexpression of TRIP6 leaded to the decreased expression of cyclin-dependent kinase inhibitors p21Cip1 and p27Kip1 and increased expression of the cell cycle regulator cyclin D1. While silencing TRIP6 triggered the opposite effect. Taken together, these findings showed that TRIP6 plays an important role in promoting HCC cells proliferation and may serve as a novel prognostic biomarker and therapeutic target in HCC.

Long non-coding RNA Myd88 promotes growth and metastasis in hepatocellular carcinoma via regulating Myd88 expression through H3K27 modification

Enhanced Myd88 expression has been found in various parenchymal tumors especially in hepatocellular carcinoma with little mechanism of its upregulation known. A lot of long non-coding RNAs are reported to regulate the protein-coding genes which have location association through various mechanisms. In our study we confirmed a new long non-coding RNA Myd88 aberrant upregulated in HCC located upstream of Myd88 and verified a positive regulation relationship between them indicating that Lnc-Myd88 might participate in the enhanced expression of Myd88 in HCC. The gain- and loss-of-function analysis revealed that Lnc-Myd88 could promote the proliferation and metastasis of HCC both in vitro and in vivo. In addition, ChIP assays demonstrated that Lnc-Myd88 might increase Myd88 expression through enhancing H3K27Ac in the promoter of Myd88 gene, thus resulting in the activation of both NF-κB and PI3K/AKT signal pathways. In conclusion, we proposed that Lnc-Myd88 might serve as a novel diagnosis and therapeutic target for HCC.

Abstract 436: Folate cycle represents a new metabolic vulnerability for hepatocellular carcinoma treatment

Abstract Hepatocellular carcinoma (HCC), primary liver cancer, ranks the third most lethal cancer worldwide due to late symptom presentation and lack of promising curative therapy. Metabolic reprogramming has been recognized as a major and new hallmark of cancer in recent years. Better understanding of its underpinning molecular mechanisms favoring cancer growth will be crucial for the development of effective HCC therapeutics. The folate cycle fuels metabolic processes and the production of metabolites essential to cell growth and tumorigenesis maintenance. Through the shuttling of a single carbon unit by a folate derivative through the tetrahydrofolate (THF) backbone in the cytoplasmic and mitochondrial compartments, metabolites like NADPH - a major cellular antioxidant for redox balance, s-adenosyl methionine (SAM) - precursor of DNA and histone methylation, and pyrimidine and purine - the building blocks of DNA are produced. We found folate to be indispensable for HCC cell growth. Furthermore, methylene-THF dehydrogenase 1-like (MTHFD1L), a key enzyme facilitating the folate cycle from the mitochondria, was found to be significantly up-regulated in HCC with association to poorer clinical features for patients. Genetic inhibition of MTHFD1L by knockdown and knockout by shRNA and CRISPR-Cas9 systems, respectively, blocked NADPH production. Rapid elevation in oxidative stress induced DNA damage and cell cycle delay; ultimately inhibiting HCC proliferation. Binding of the transcription factor NRF2, a potent protector of oxidative stress, and MTHFD1L was confirmed by ChIP assay. NRF2 over-expression using the CRISPR-activating system in HCC cells further highlighted the dependent relationship between NRF2 and MTHFD1L. Metabolomics analysis showed that MTHFD1L knockdown caused a disruption to the folate cycle and accumulation of serine. Surprisingly, MTHFD1L knockdown did not reduce the levels of SAM and nucleotides. Knockdown of MTHFD1L in HCC cells significantly inhibited primary liver tumor growth and lung metastasis in orthotopic liver implantation model. Therapeutically, the administration of methotrexate, an anti-folate agent, sensitized HCC cells towards Sorafenib treatment both in vitro and vivo. The folate cycle represents a metabolic vulnerability and attractive therapeutic target for HCC. Inhibition of MTHFD1L disrupts the folate cycle and sensitizes HCC cells towards its convention treatment agent, Sorafenib in various HCC mouse models. Our investigation unravels a metabolic vulnerability in cancer which contributes to better understanding and is beneficial for the development of precise inhibitors specifically targeting associated pathways. Citation Format: Derek Lee, Iris Ming-Jing Xu, David Kung-Chun Chiu, Robin Kit-Ho Lai, Chun-Ming Wong, Irene Oi-Lin Ng, Carmen Chak-Lui Wong. Folate cycle represents a new metabolic vulnerability for hepatocellular carcinoma treatment [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 436. doi:10.1158/1538-7445.AM2017-436

Long noncoding RNA linc00462 promotes hepatocellular carcinoma progression

BackgroundHepatocellular carcinoma (HCC) represents one of the most common malignancies worldwide. In two pubic long noncoding RNA (lncRNA) profiling studies of HCC, linc00462 was consistently upregulated. We analyzed the clinical significance and biological role of linc00462 in HCC. MethodsWe performed quantitative real-time PCR analysis to determine the levels of linc00462 in HCC tissues from 49 patients. Functional analysis was performed in cell lines and in an animal model to support clinical findings. ResultsOur data showed that linc00462 was significantly upregulated in HCC tissues compared with matched normal tissues. The knockdown of linc00462 in HCC cells resulted in a much less aggressive oncogenic phenotype, and linc00462 downregulation contribute to the inactivation of the PI3K/AKT signaling pathway. Conclusionslinc00462 may be a potential therapeutic target in HCC.

Eukaryotic elongation factor 2 is a prognostic marker and its kinase a potential therapeutic target in HCC

Hepatocellular carcinoma is a cancer with increasing incidence and largely refractory to current anticancer drugs. Since Sorafenib, a multikinase inhibitor has shown modest efficacy in advanced hepatocellular carcinoma additional treatments are highly needed. Protein phosphorylation via kinases is an important post-translational modification to regulate cell homeostasis including proliferation and apoptosis. Therefore kinases are valuable targets in cancer therapy. To this end we performed 2D differential gel electrophoresis and mass spectrometry analysis of phosphoprotein-enriched lysates of tumor and corresponding non-tumorous liver samples to detect differentially abundant phosphoproteins to screen for novel kinases as potential drug targets. We identified 34 differentially abundant proteins in phosphoprotein enriched lysates. Expression and distribution of the candidate protein eEF2 and its phosphorylated isoform was validated immunohistochemically on 78 hepatocellular carcinoma and non-tumorous tissue samples. Validation showed that total eEF2 and phosphorylated eEF2 at threonine 56 are prognostic markers for overall survival of HCC-patients. The activity of the regulating eEF2 kinase, compared between tumor and non-tumorous tissue lysates by in vitro kinase assays, is more than four times higher in tumor tissues. Functional analyzes regarding eEF2 kinase were performed in JHH5 cells with CRISPR/Cas9 mediated eEF2 kinase knock out. Proliferation and growth is decreased in eEF2 kinase knock out cells.ConclusioneEF2 and phosphorylated eEF2 are prognostic markers for survival of hepatocellular carcinoma patients and the regulating eEF2 kinase is a potential drug target for tumor therapy.

Overexpression of SMOC2 Attenuates the Tumorigenicity of Hepatocellular Carcinoma Cells and Is Associated With a Positive Postoperative Prognosis in Human Hepatocellular Carcinoma.

Secreted modular calcium binding protein-2 (SMOC2), a recently identified matricellular protein that belongs to the SPARC protein family, has been reported to be downregulated in various cancers. The purpose of this study was to investigate the clinical significance and biological function of SMOC2 in human hepatocellular carcinoma. Real-time quantitative PCR and western blotting analyses revealed that SMOC2 mRNA and protein levels were significantly downregulated in human HCC tissues compared to the matched adjacent normal tissues. Clinicopathological analysis indicated that SMOC2 expression was significantly associated with tumor size, number of tumors, tumor-node-metastasis (TNM) stage and distant metastasis. Kaplan-Meier survival analysis showed that high tumor SMOC2 expression was associated with improved overall survival and disease-free survival in patients with HCC. Functional analyses (cell proliferation and colony formation assays, cell migration and invasion assays, cell cycle and apoptosis assays) demonstrated that stable overexpression of SMOC2 using a lentiviral vector significantly inhibited cell proliferation, colony formation, migration and invasion, and induced G0/G1 phase arrest in HCC cells in vitro. In addition, experiments with a mouse model revealed the suppressed effect of SMOC2 on HCC tumorigenicity and metastases in vivo. These results suggest that SMOC2 functions as a tumor suppressor during the development of HCC and may represent an effective prognostic factor and novel therapeutic target for HCC.

Paraoxonase 3 inhibits cell proliferation and serves as a prognostic predictor in hepatocellular carcinoma.

Paraoxonase 3 (PON3) exerts prominent anti-inflammation and anti-oxidation properties mainly at the cellular level, and is primarily expressed in the liver. However, its role in HCC remains unexplored. Here, we investigated the expression pattern, clinical significance, and function of PON3 in HCC. PON3 mRNA and protein levels were respectively determined in two large cohorts using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) of tissue microarray. We found that PON3 was downregulated in most HCCs. Kaplan-Meier and log-rank test showed that PON3 downregulation predicted shorter recurrence-free survival (RFS) and overall survival (OS) time in all HCC patients, especially early-stage HCC patients. Cox regression analysis revealed that the PON3 downregulation was an independent risk factor for RFS and OS. Gain- and loss-of-function experiments revealed that PON3 suppressed cell proliferation in vivo and in vitro, which was attributed to its cell-cycle arrest effect. In addition, microarray analysis showed that some pro-proliferative genes were elevated when PON3 was knockdown, and these genes possibly involved in the underlying mechanisms. In conclusion, our studies reveal the cell proliferation inhibitory function of PON3 and offer a potential prognostic predictor and therapeutic target for HCC.

A CD13 inhibitor, ubenimex, synergistically enhances the effects of anticancer drugs in hepatocellular carcinoma.

Cancer stem cells (CSCs) were reported to be involved in resistance to chemo/radiation therapy. We previously reported that CD13 was both a marker of CSCs and a candidate therapeutic target in HCC. In the present study, we explored the antitumor effect of a combined therapy, where ubenimex, a CD13 inhibitor, was combined with conventional anticancer drugs, fluorouracil (5-FU), cisplatin (CDDP), doxorubicin (DXR) and sorafenib (SOR), and we elucidated the mechanism of these combination therapies. We evaluated changes in the expression of CD13 before and after treatment with anticancer drugs and with or without ubenimex in the human HCC cell lines HuH7 and PLC/PRF/5. The interactions between the anticancer drugs and ubenimex were determined with isobologram analyses. We analyzed cell cycle, apoptosis, and intracellular reactive oxygen species (ROS) levels to explore the mechanisms of the combination therapies. In both cell lines, the expression of CD13 increased after a 72-h exposure to each anticancer drug alone (P<0.05), and the expression of CD13 decreased with ubenimex administration (P<0.05). Isobologram analyses indicated that ubenimex had synergistic effects with 5-FU, CDDP and DXR, and an additive effect with SOR. Cell cycle analyses showed that ubenimex decreased the proportion of cells in G0/G1. Ubenimex enhanced the effects of 5-FU, CDDP and DXR by increasing apoptosis and intracellular ROS levels. In combination therapies, ubenimex synergistically enhanced the antitumor effects of 5-FU, CDDP and DXR on cell cycle regulation and apoptosis induction in HCC cell lines. The effects of ubenimex were due to increased intracellular ROS levels.

HMDB and 5-AzadC Combination Reverses Tumor Suppressor CCAAT/Enhancer-Binding Protein Delta to Strengthen the Death of Liver Cancer Cells.

Hepatocellular carcinoma (HCC) can arise from chronic inflammation due to viral infection, organ damage, drug toxicity, or alcohol abuse. Moreover, gene desensitization via aberrant CpG island methylation is a frequent epigenetic defect in HCC. However, the details of how inflammation is linked with epigenetic-mediated desensitization of tumor suppressor genes remains less investigated. In this study, we found that loss of CEBPD enhances the growth of liver cancer cells and is associated with the occurrence of liver cancers, as determined by the assessment of clinical specimens and in vivo animal models. Moreover, E2F1-regulated epigenetic axis attenuated CEBPD expression in liver cancer cells. CEBPD is responsive to the hydroxymethyldibenzoylmethane (HMDB)-induced p38/CREB pathway and plays an important role in the HMDB-induced apoptosis of cancer cells. Regarding depression of epigenetic effects to enhance HMDB-induced CEBPD expression, the combination of HMDB and 5-Aza-2'-deoxycytidine (5-AzadC) could enhance the death of liver cancer cells and reduce the tumor formation of Huh7 xenograft mice. In conclusion, these results suggest that CEBPD could be a useful diagnostic marker and therapeutic target in HCC. The results also reveal the therapeutic potential for low-dose 5-AzadC to enhance the HMDB-induced death of HCC cells.