Future of molecular profiling of human hepatocellular carcinoma

Regulatory MiR-148a-ACVR1/BMP circuit defines a cancer stem cell-like aggressive subtype of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third most common cancer in Asia. HCC has heterogeneous etiologic and molecular profiles and a varied response to therapeutics. The high recurrence rate and curtailed survival in this cancer are attributed to its resistance to therapy. The ultimate goal is to develop a more effective personalized therapeutic strategy for HCC, but the first step is to develop a system for classifying the disease on the basis of molecular biomarkers. To that end, we performed mRNA and microRNA (miRNA) expression profiling in 100 HCC tissues. Clustering analysis of informative genes identified two robust subtypes, which were validated by an independent dataset. The subtype characterized by a cancer stem cell-like signature was clinically aggressive and associated with poor survival. Integrated analysis of miRNA and mRNA expression in this subtype showed that miR-148a was expressed at a significantly lower level in these tumors than in the other subtype. MiR-148a has been shown to directly suppress the expression of activin A receptor type 1 (ACVR1), a key receptor in the signaling pathway of the bone morphogenetic proteins (BMPs), which regulate many stem cell markers as well as the clinically important cytokine interleukin-8 (IL-8). Increased expression of ACVR1 and its downstream genes EPCAM, CD24, CD90, and IL-8 was associated with shorter survival in a larger cohort of 227 HCC cases. Introduction of miR-148a resulted in suppressed tumor phenotypes both in vitro and in vivo.

CONCLUSION

We identified a clinically aggressive stem cell-like subtype of HCC that is characterized by an miR-148a-ACVR1-BMP-Wnt circuit. We propose that miR-148a may serve as a prognostic biomarker and therapeutic target for this subtype of HCC.

Silencing of hypoxia-inducible factor-1β induces anti-tumor effects in hepatoma cell lines under tumor hypoxia

Dimerization of hypoxia-inducible factor-1 beta (HIF-1β) [aryl hydrocarbon receptor nuclear translocator (ARNT)] with HIF-1α is involved in various aspects of cancer biology, including proliferation and survival under hypoxic conditions. We investigated the in vitro mechanism by which silencing of HIF-1β leads to the suppression of tumor cell growth and cellular functions. Various hepatocellular carcinoma (HCC) cell lines (Huh-7, Hep3B, and HepG2) were transfected with small interfering RNA (siRNA) against HIF-1β (siHIF-1β) and cultured under hypoxic conditions (1% O2 for 24 h). The expression levels of HIF-1β, HIF-1α, and growth factors were examined by immunoblotting. Tumor growth was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and tumor activity was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling, tumor cell invasion, and migration assays. Under hypoxic conditions, silencing of HIF-1β expression suppressed tumor cell growth and regulated the expression of tumor growth-related factors, such as vascular endothelial growth factor, epidermal growth factor, and hepatocyte growth factor. Suppression of tumor cell invasion and migration was also demonstrated in HIF-1β-silenced HCC cell lines. Silencing of HIF-1β expression may induce anti-tumor effects under hypoxic conditions in HCC cell lines.

Deciphering cancer heterogeneity: the biological space

Most lethal solid tumors including hepatocellular carcinoma (HCC) are considered incurable due to extensive heterogeneity in clinical presentation and tumor biology. Tumor heterogeneity may result from different cells of origin, patient ethnicity, etiology, underlying disease, and diversity of genomic and epigenomic changes which drive tumor development. Cancer genomic heterogeneity thereby impedes treatment options and poses a significant challenge to cancer management. Studies of the HCC genome have revealed that although various genomic signatures identified in different HCC subgroups share a common prognosis, each carries unique molecular changes which are linked to different sets of cancer hallmarks whose misregulation has been proposed by Hanahan and Weinberg to be essential for tumorigenesis. We hypothesize that these specific sets of cancer hallmarks collectively occupy different tumor biological space representing the misregulation of different biological processes. In principle, a combination of different cancer hallmarks can result in new convergent molecular networks that are unique to each tumor subgroup and represent ideal druggable targets. Due to the ability of the tumor to adapt to external factors such as treatment or changes in the tumor microenvironment, the tumor biological space is elastic. Our ability to identify distinct groups of cancer patients with similar tumor biology who are most likely to respond to a specific therapy would have a significant impact on improving patient outcome. It is currently a challenge to identify a particular hallmark or a newly emerged convergent molecular network for a particular tumor. Thus, it is anticipated that the integration of multiple levels of data such as genomic mutations, somatic copy number aberration, gene expression, proteomics, and metabolomics, may help us grasp the tumor biological space occupied by each individual, leading to improved therapeutic intervention and outcome.

The transcription factor GLI1 mediates TGFβ1 driven EMT in hepatocellular carcinoma via a SNAI1-dependent mechanism

The role of the epithelial-to-mesenchymal transition (EMT) during hepatocellular carcinoma (HCC) progression is well established, however the regulatory mechanisms modulating this phenomenon remain unclear. Here, we demonstrate that transcription factor glioma-associated oncogene 1 (GLI1) modulates EMT through direct up-regulation of SNAI1 and serves as a downstream effector of the transforming growth factor-β1 (TGFβ1) pathway, a well-known regulator of EMT in cancer cells. Overexpression of GLI1 increased proliferation, viability, migration, invasion, and colony formation by HCC cells. Conversely, GLI1 knockdown led to a decrease in all the above-mentioned cancer-associated phenotypes in HCC cells. Further analysis of GLI1 regulated cellular functions showed that this transcription factor is able to induce EMT and identified SNAI1 as a transcriptional target of GLI1 mediating this cellular effect in HCC cells. Moreover, we demonstrated that an intact GLI1-SNAI1 axis is required by TGFβ1 to induce EMT in these cells. Together, these findings define a novel cellular mechanism regulated by GLI1, which controls the growth and EMT phenotype in HCC.

Surgical treatment for large hepatocellular carcinoma: does size matter?

Despite significant progress in the management of hepatocellular carcinoma (HCC), patients with large HCC (defined as >10 cm) continue to present a significant challenge. The goal of this paper is to review the existing literature regarding large HCC, with emphasis on identifying the issues and challenges involved in approaching these tumours surgically. A computerized search was made of the Medline database from January 1992 to December 2010. The MESH heading 'large' or 'huge' in combination with the keyword 'hepatocellular carcinoma' was used. After excluding further studies that identified 'large' HCC as less than 10 cm and/or sequential publications with overlapping patient populations, the search produced a study population of 22 non-duplicated papers, reporting on a total of 5223 patients with HCC tumours >10 cm. Regarding resection for large HCC, the overall 5-year survival in these studies ranged from 25% to 45%, with few outliers on both sides, whereas in most studies, the 5-year disease-free survival ranged between 15% and 35%, with the only exception being studies with patients with single lesions and no cirrhosis showing disease-free survival of 41% and 56%, respectively. Risk factors identified included vascular invasion, cirrhosis, high level of alpha-fetoprotein and the presence of multiple lesions. Finally, liver transplantation, although an attractive concept, did not appear to offer a survival benefit in any of the studies. In conclusion, identifying the risk factors that affect the outcome in patients undergoing surgery for large HCC is critical. The reason is that surgical resection can have excellent outcomes in carefully selected patients.

Next-generation sequencing of microRNAs for breast cancer detection

It is reported that different microRNA (miRNA) profiles can be detected in the blood of cancer patients. We investigated that whether the key serum miRNAs could discriminate patients with and without breast cancer. This study was divided into three parts: (1) miRNA marker discovery using SOLiD sequencing-based miRNA profiling on cancerous and adjacent noncancerous breast tissue of one breast cancer patient; (2) marker selection and validation by real-time PCR on a small set of serum; (3) gene ontology analysis of the key miRNA target genes. Of genome-wide tissue miRNA expression analysis, five miRNAs were found to be altered more than fivefold by SOLiD sequencing (i.e., miR-29a, miR-23a, miR-23b, miR-192, and miR-21). All the five miRNAs were validated on the 20 breast cancer patients and 20 controls. miR-29a and miR-21 were significantly increased in the serum of breast cancer patients (P < .05). Gene ontology analysis of the target genes revealed enrichment for special biological process categories, that is, signal transduction, development, apoptosis, cell proliferation, and cell adhesion. SOLiD sequencing provides a promising method for cancer-related miRNA profiling. Serum miRNAs may be useful biomarkers for breast cancer detection.

MicroRNAs as new players in the genomic galaxy and disease puzzles

Abstract MicroRNAs (miRNAs) are a large family of short, single-stranded, highly conserved noncoding RNAs involved in gene regulation that can regulate gene expression through sequence-specific base pairing with target messenger RNAs (mRNAs). miRNAs have been implicated in the development of a wide variety of cancers as well as heart disease and other diseases. This review describes the role of miRNAs in human disease, methodology for evaluating miRNA gene expression, and the potential role of miRNAs as therapeutic agents and targets for the treatment of disease.

Role of microRNA-199a-5p and discoidin domain receptor 1 in human hepatocellular carcinoma invasion

Background

Micro-ribonucleic acid (miRNA)-199a-5p has been reported to be decreased in hepatocellular carcinoma (HCC) compared to normal tissue. Discoidin domain receptor-1 (DDR1) tyrosine kinase, involved in cell invasion-related signaling pathway, was predicted to be a potential target of miR-199a-5p by the use of miRNA target prediction algorithms. The aim of this study was to investigate the role of miR-199a-5p and DDR1 in HCC invasion.

Methods

Mature miR-199a-5p and DDR1 expression were evaluated in tumor and adjacent non-tumor liver tissues from 23 patients with HCC undergoing liver resection and five hepatoma cell lines by the use of real-time quantitative RT-PCR (qRT-PCR) analysis. The effect of aberrant miR-199a-5p expression on cell invasion was assessed in vitro using HepG2 and SNU-182 hepatoma cell lines. Luciferase reporter assay was employed to validate DDR1 as a putative miR-199a-5p target gene. Regulation of DDR1 expression by miR-199a-5p was assessed by the use qRT-PCR and western blotting analysis.

Results

A significant down-regulation of miR-199a-5p was observed in 65.2% of HCC tissues and in four of five cell lines. In contrast, DDR1 expression was significantly increased in 52.2% of HCC samples and in two of five cell lines. Increased DDR1 expression in HCC was associated with advanced tumor stage. DDR1 was shown to be a direct target of miR-199a-5p by luciferase reporter assay. Transfection of miR-199a-5p inhibited invasion of HepG2 but not SNU-182 hepatoma cells.

Conclusions

Decreased expression of miR-199a-5p contributes to increased cell invasion by functional deregulation of DDR1 activity in HCC. However, the effect of miR-199a-5p on DDR1 varies among individuals and hepatoma cell lines. These findings may have significant translational relevance for development of new targeted therapies as well as prognostic prediction for patients with HCC.

Stathmin1 overexpression associated with polyploidy, tumor-cell invasion, early recurrence, and poor prognosis in human hepatoma

Frequent intrahepatic metastasis causes early tumor recurrence and dismaying prognosis of human hepatocellular carcinoma (HCC). We recently identified overexpression of stathmin1 (STMN1) in human HCC. This study was designed to elucidate the clinical and biological significance of overexpression of STMN1 in HCC. Expression of STMN1 was conducted by quantitative reverse transcription-polymerase chain reaction and immunoblotting assays on 58 pairs of HCC and para-tumor liver tissues from patients with HCC along with normal liver tissues as the controls. Association of STMN1 overexpression with tumor recurrence and prognosis was investigated by Kaplan-Meier cumulative survival and Cox Regression analyses. Roles of STMN1 in cell cycle, cell motility, and invasion were determined by in vitro assays. STMN1 overexpression in hepatoma was strongly associated with local invasion (P = 0.031), early recurrence (P = 0.002), and poor prognosis (P = 0.005), and was an independent indicator for tumor recurrence (P = 0.0045). STMN1 overexpression further identified subgroups of HCC patients with higher tumor recurrence and worse prognosis among HCC patients with early tumor stage (T1) or intermediate histological grades (G2 and G3), both of whom represent the majority of HCC patients receiving primary curative hepatectomy. Silencing STMN1 expression via RNA interference suppressed invasion activity, while ectopic expression of STMN1 enhanced cell invasion and caused polyploidy of cells. In conclusion, STMN1 overexpression could predict early tumor recurrence and poor prognosis, particularly at early stage of hepatoma. Overexpression of STMN1 promoted polyploidy formation, tumor-cell invasion, and intrahepatic metastasis, suggesting that STMN1 can be a target for anti-cancer therapy of human hepatoma.

Prediction of progression-free survival in patients presenting with hepatocellular carcinoma within the Milan criteria

Transplantation is the treatment of choice for hepatocellular carcinoma (HCC) meeting the Milan criteria. HCC and chronic liver diseases have distinct natural histories for which an equitable transplant policy must account. We enrolled and prospectively followed at a single center 206 consecutive HCC patients that presented within the Milan criteria. Patients were treated per the Barcelona Clinic Liver Cancer (BCLC) algorithm; 95% received resection, ablation, or transarterial chemoembolization. The median follow-up was 16 months. Progression occurred in 84 patients, and 8 patients died. Risk factors for the time to disease progression (death or progression beyond T2) were analyzed in 170 patients with a complete data set. Risk factors with the strongest relationship to progression included tumor diameter and tumor persistence/recurrence after local therapy (hazard ratios of 1.51 and 2.75, respectively, when transplanted patients were censored at the time of transplantation and hazard ratios of 1.53 and 3.66, respectively, when transplantation was counted as an event; P < or = 0.0001). To evaluate the current Model for End-Stage Liver Disease (MELD) exception, we compared the expected progression rate (PR) with our observed PR in 133 stage T2 patients. The current policy resulted in a large overestimation of the PR for T2 HCC and an unsatisfactory performance [Harrell's concordance index (C index) = 0.60, transplant censored; C index = 0.55, transplant as progression]. Risk factors for progression that were identified by univariate analysis were considered for multivariate analysis. With these risk factors and the patients' natural MELD scores, an adjusted model applicable to organ allocation was generated, and this decreased the discrepancy between the expected and observed PRs (C index = 0.66, transplant censored; C index = 0.69, transplant as progression). In conclusion, the current MELD exception largely overestimates progression in T2 patients treated according to the BCLC guidelines. The tumor response to resective or ablative treatment can predict tumor progression beyond the Milan criteria, and it should be taken into account in models designed to prioritize organ allocation.

dUTP pyrophosphatase expression correlates with a poor prognosis in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a malignancy with a poor prognosis, partly owing to the lack of biomarkers that support its classification in line with its malignant nature. To discover a novel molecular marker that is related to the efficacy of treatment for HCC and its biological nature, we performed serial analysis of gene expression (SAGE) in HCC, normal liver and cirrhotic liver tissues.

METHODS

Gene expression profiles of HCC tissues and non-cancerous liver tissues were obtained by SAGE. Suppression of the target gene by RNA interference was used to evaluate its role in HCC in vitro. The relation of the identified marker and prognosis was statistically examined in surgically resected HCC patients.

RESULTS

We identified significant overexpression of DUT, which encodes dUTP pyrophosphatase (dUTPase), in HCC tissue, and this was confirmed in about two-thirds of the HCC samples by reverse-transcription polymerase chain reaction (n=20). Suppression of dUTPase expression using short interfering RNAs inhibited cell proliferation and sensitized HuH7 cells to 5-fluorouracil treatment. Nuclear dUTPase expression was observed in 36.6% of surgically resected HCC samples (n=82) evaluated by immunohistochemistry, and its expression was significantly correlated with the histological grades (P=0.0099). Notably, nuclear dUTPase expression correlated with a poor prognosis with statistical significance (HR, 2.47; 95% CI, 1.08-5.66; P=0.032).

CONCLUSION

Taken together, these results suggest that nuclear dUTPase may be a good biomarker for predicting prognosis in HCC patients after surgical resection. Development of novel dUTPase inhibitors may facilitate the eradication of HCC.

Involvement of miR-199a downregulation in the preventive effects of Jianpi Jiedu Recipe against experimental hepatocarcinoma in rats

AIM: To investigate the preventive effects of Jianpi Jiedu Recipe against diethylnitrosamine-induced hepatocarcinoma in rats and explore the involvement of miR-199a downregulation in this process.

METHODS: Male Wistar rats were randomly divided into three groups: normal control group (n = 25), model group (n = 40 ) and prevention group (n = 40). The normal control group was given normal saline [10 mL/(kg•d) ig] for 12 weeks, the model group was given diethylnitrosamine dissolved in drinking water (80 ppm) at a dose of 8 mg/(kg•d) for the same duration, and the prevention group was given both diethylnitrosamine at the same dose and Jianpi Jiedu Recipe [17.5 g/(kg•d), ig] for the same duration. Five rats in each group were executed at weeks 4, 8, 12 and 16, respectively, and the remaining rats were killed at week 20. Meanwhile, the mortality, incidence of ascites, and liver and spleen index were measured. Hematoxylin-eosin staining (HE) was used to examine hepatic pathological changes. The expression of miR-199a mRNA was detected by real-time reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS: At week 20, the mortality rate and the incidence rate of ascites were 0% and 0% in the normal control group, 42.5% and 87.5% in the model group, and 17.5% and 44.4% in the prevention group, respectively. The mortality rate and the incidence of ascites were significantly lower in the prevention group than in the model group (both P < 0.05). At week 16, the incidence of HCC was 100% in both the model group and prevention group and 0% in the normal control group, the incidence of grade III liver cancer was 100% (5/5) in the model group, and the incidences of grade I, II and III liver cancer were 40% (2/5), 40% (2/5 ) and 20% (1/5) in the prevention group, respectively. Compared with the model group, the liver and spleen index in the prevention group were significantly reduced at all time points (all P < 0.01). Real-time RT-PCR results showed that the expression of miR-199a was significantly upregulated in the model group. However, miR-199a expression was significantly downregulated in the prevention group at all time points except at week 16 (all P < 0.01).

CONCLUSION: Jianpi Jiedu Recipe has good preventive effects against hepatocarcinoma in rats perhaps partly by downregulating miR-199a expression.

Pseudomonas aeruginosa: mannose sensitive hemagglutinin inhibits the growth of human hepatocarcinoma cells via mannose-mediated apoptosis

A vaccine derived from the outer membrane proteins of the Gram-negative bacterium Pseudomonas aeruginosa has been shown to have immune modulatory properties. An inactivated mutant strain of P. aeruginosa with mannose sensitive hemagglutinin fimbria (PA-MSHA) has been used for adjuvant therapy for malignant cancer. In this study, the growth of human hepatocellular carcinoma Hep G2 and BEL-7402 cells is inhibited by PA-MSHA, but not by mannose-cleaved PA-MSHA. PA-MSHA-treated cells arrested in the S phase of the cell cycle and underwent apoptosis. We hypothesize that apoptosis induced by treatment of Hep G2 and BEL-7402 cells with PA-MSHA is mediated by the mannose residues of PA-MSHA and is propagated through the extrinsic apoptosis pathway directly through caspase-8. These data provide mechanistic details for the potential application of PA-MSHA-based treatment of hepatocellular carcinoma.

Advances in the relationship between microRNA and mechanism of human primary hepatocellular carcinoma

In genetics, microRNAs (miRNAs) are single-stranded RNA molecules of 19-22 nucleotides (nts) in length, which are non-coding RNAs and negatively down-regulate expression of their target genes in post-transcriptional level. Recently, many studies have shown that miRNAs are involved in the regulation of cell proliferation, differentiation, apoptosis and so on. The mutation, depletion or dysfunction of miRNAs was closely associated with occurrence and progression of human cancers. This review mainly discusses the advances in the relationship between miRNAs and hepatocellular carcinoma (HCC) in recent years.

miR-122, a paradigm for the role of microRNAs in the liver

Recent studies have uncovered profound and unexpected roles for a family of tiny regulatory RNAs, known as microRNAs (miRNAs), in the control of diverse aspects of hepatic function and dysfunction, including hepatocyte growth, stress response, metabolism, viral infection and proliferation, gene expression, and maintenance of hepatic phenotype. In liver cancer, misexpression of specific miRNAs suggests diagnostic and prognostic significance. Here, we review the biology of the most abundant miRNA in human liver, miR-122, and consider the diversity of its roles in the liver. We provide a compilation of all miRNAs expressed in the liver, and consider some possible therapeutic opportunities for exploiting miRNAs in the different settings of liver diseases.