Molecular pathogenesis of human hepatocellular carcinoma

Advances in Histological and Molecular Classification of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a primary liver cancer characterized by hepatocellular differentiation. HCC is molecularly heterogeneous with a wide spectrum of histopathology. The prognosis of patients with HCC is generally poor, especially in those with advanced stages. HCC remains a diagnostic challenge for pathologists because of its morphological and phenotypic diversity. However, recent advances have enhanced our understanding of the molecular genetics and histological subtypes of HCC. Accurate diagnosis of HCC is important for patient management and prognosis. This review provides an update on HCC pathology, focusing on molecular genetics, histological subtypes, and diagnostic approaches.

Hepatocellular Carcinomas with Concomitant Mutations of TERT, TP53, and CTNNB1: Is There a Role for Artificial Intelligence?

TP53, CTNNB1, and TERT-promoter mutations are the most common driver mutations in hepatocellular carcinoma (HCC). The morphological and genetical HCC heterogeneities are difficult to discriminate by the eye of the pathologist. Here, we describe two rare cases of HCC with simultaneous co-mutation of all three of genes, which represent a poorly described occurrence in the literature. In these two cases, areas with different tumor grade and different β-catenin and Glutamine Synthetase expression (performed by automated immunohistochemistry) were observed. NGS analysis was performed in these different areas, to check for potential diversity of mutation burden on the different regions, but no differences were found: all micro-areas analyzed showed the co-presence of mutations in TP53, CTNNB1, and TERT. The evidence that all mutations were found in all the different areas analyzed by NGS leads to hypothesize that the tumor is not composed of different clones harboring different mutations. All the variants are harbored by the same neoplastic clone, albeit leading to different phenotypes. Mutation prediction Artificial Intelligence models could help the morpho-genetic classification of HCC in the future, since they can find variabilities not obvious to the human eye, with increased sensitivity, specificity and reproducibility.

Pathophysiological role of prostaglandin E synthases in liver diseases

Prostaglandin E synthases (PGESs) convert cyclooxygenase (COX)-derived prostaglandin H2 (PGH2) into prostaglandin E2 (PGE2) and comprise at least three types of structurally and biologically distinct enzymes. Two of these, namely microsomal prostaglandin E synthase-1 (mPGES-1) and mPGES-2, are membrane-bound enzymes. mPGES-1 is an inflammation-inducible enzyme that converts PGH2 into PGE2. mPGES-2 is a bifunctional enzyme that generally forms a complex with haem in the presence of glutathione. This enzyme can metabolise PGH2 into malondialdehyde and can produce PGE2 after its separation from haem. In this review, we discuss the role of PGESs, particularly mPGES-1 and mPGES-2, in the pathogenesis of liver diseases. A better understanding of the roles of PGESs in liver disease may aid in the development of treatments for patients with liver diseases.

Phytochemical and Pharmacological Role of Liquiritigenin and Isoliquiritigenin From Radix Glycyrrhizae in Human Health and Disease Models

The increasing lifespan in developed countries results in age-associated chronic diseases. Biological aging is a complex process associated with accumulated cellular damage by environmental or genetic factors with increasing age. Aging results in marked changes in brain structure and function. Age-related neurodegenerative diseases and disorders (NDDs) represent an ever-growing socioeconomic challenge and lead to an overall reduction in quality of life around the world. Alzheimer’s disease (AD) and Parkinson’s disease (PD) are most common degenerative neurological disorders of the central nervous system (CNS) in aging process. The low levels of acetylcholine and dopamine are major neuropathological feature of NDDs in addition to oxidative stress, intracellular calcium ion imbalance, mitochondrial dysfunction, ubiquitin-proteasome system impairment and endoplasmic reticulum stress. Current treatments minimally influence these diseases and are ineffective in curing the multifunctional pathological mechanisms. Synthetic neuroprotective agents sometimes have negative reactions as an adverse effect in humans. Recently, numerous ethnobotanical studies have reported that herbal medicines for the treatment or prevention of NDDs are significantly better than synthetic drug treatment. Medicinal herbs have traditionally been used around the world for centuries. Radix Glycyrrhizae (RG) is the dried roots and rhizomes of Glycyrrhiza uralensis or G. glabra or G. inflata from the Leguminosae/Fabaceae family. It has been used for centuries in traditional medicine as a life enhancer, for the treatment of coughs and influenza, and for detoxification. Diverse chemical constituents from RG have reported including flavanones, chalcones, triterpenoid saponins, coumarines, and other glycosides. Among them, flavanone liquiritigenin (LG) and its precursor and isomer chalcone isoliquiritigenin (ILG) are the main bioactive constituents of RG. In the present review, we summarize evidence in the literature on the structure and phytochemical properties and pharmacological applications of LG and ILG in age-related diseases to establish new therapeutics to improve human health and lifespan.

ARHGAP9 suppresses the migration and invasion of hepatocellular carcinoma cells through up-regulating FOXJ2/E-cadherin

Rho GTPase activating protein 9 (ARHGAP9), a member of RhoGAP family, has been identified as a RhoGAP for Cdc42 and Rac1. Here, we aimed to clarify the expression and functional role of ARHGAP9 in hepatocellular carcinoma (HCC). By analyzing TCGA (The Cancer Genome Atlas) LIHC (liver hepatocellular carcinoma) database, we found that ARHGAP9 expression was lower in HCC tissues than in normal liver tissues, and that patients with ARHGAP9 lower expression had a significant shorter overall survival time than those with ARHGAP9 higher expression. Cell counting kit-8 (CCK-8), transwell assays and in vivo experimental lung metastasis assay revealed that ARHGAP9 overexpression could inhibit HCC cell proliferation, migration and invasion, as well as HCC lung metastases. By next-generation RNA-sequencing, we identified that a transcription factor, Forkhead Box J2 (FOXJ2), was significantly induced by ARHGAP9 overexpression in HepG2 cells. Ectopic expression of FOXJ2 in HCC cell lines also exerted inhibitory effects on cell migration and invasion. Moreover, the inhibitory effects of ARHGAP9 on HCC cell migration and invasion was significantly attenuated by FOXJ2 knockdown. Luciferase reporter assay demonstrated that ARHGAP9 enhanced the transcription of E-cadherin (CDH1) via FOXJ2. Chromatin immunoprecipitation (ChIP) assay demonstrated that FOXJ2 modulated the transcription of E-cadherin (CDH1) by directly binding to its promoter. Furthermore, Pearson's correlation analysis indicated that the mRNA levels of ARHGAP9 in HCC tissues were positively correlated with the mRNA levels of FOXJ2 and CDH1. These data clearly show that ARHGAP9/FOXJ2 inhibit cell migration and invasion during HCC development via inducing the transcription of CDH1.

Characterization of a new monoclonal anti-glypican-3 antibody specific to the hepatocellular carcinoma cell line, HepG2

AIM

To characterize the antigen on HepG2 cell that is specifically recognized by a new monoclonal antibody raised against human liver heparan sulfate proteoglycan (HSPG), clone 1E4-1D9.

METHODS

The antigen recognized by mAb 1E4-1D9 was immunoprecipitated and its amino acid sequence was analyzed LC/MS. The transmembrane domain, number of cysteine residues, and glycosylation sites were predicted from these entire sequences. Data from amino acid analysis was aligned with glypican-3 (https://www.ebi.ac.uk/Tools/msa/clustalo/). The competitive reaction of mAb 1E4-1D9 and anti-glypican-3 on HepG2 cells was demonstrated by indirect immunofluorescence and analyzed by flow cytometry. Moreover, co-immunoprecipitation of mAb 1E4-1D9 and anti-glypican-3 was performed in HepG2 cells by Western immunoblotting. The recognition by mAb 1E4-1D9 of a specific epitope on solid tumor and hematopoietic cell lines was studied using indirect immunofluorescence and analyzed by flow cytometry.

RESULTS

Monoclonal antibody 1E4-1D9 reacted with an HSPG isolated from human liver and a band of 67 kD was detected under both reducing and non-reducing conditions. The specific antigen pulled down by mAb 1E4-1D9, having a MW of 135 kD, was analyzed. The results showed two sequences of interest, gi30722350 (1478 amino acid) and gi60219551 (1378 amino acid). In both sequences no transmembrane regions were observed. Sequence number gi30722350 was 99.7% showed a match to FYCO1, a molecule involved in induction of autophagy. Sequence number gi60219551 contained 15 cysteines and 11 putative glycosylation sites with 6 predicted N-glycosylation sites. It was also matched with all PDZ domain proteins. Moreover, it showed an 85.7% match to glypican-3. Glypican-3 on HepG2 cells competitively reacted with both phycoerythrin-conjugated anti-glypican-3 and mAb 1E4-1C2 and resulted in an increase of double-stained cell population when higher concentration of mAb 1E4-1D9 was used. Moreover, antigens precipitated from HepG2 cell by anti-glypican-3 could be detected by mAb 1E4-1D9 and vice versa. The recognition of antigens, on other solid tumor cell lines, by mAb 1E4-1D9 was studied. The results demonstrated that mAb 1E4-1D9 reacted with Huh7, HepG2, HT29, MCF7, SW620, Caco2, B16F1, U937, K562 and Molt4 cells. It was also found to be weakly positive to SW1353 and HL60 and negative to H460 and Hela cell lines.

CONCLUSION

All findings show that mAb 1E4-1D9 specifically recognizes glypican-3. Moreover, a new partner molecule of glypican-3, FYCO1 is proposed based on the results from co-precipitation studies.

DNA-PKcs: A promising therapeutic target in human hepatocellular carcinoma?

Hepatocellular carcinoma (HCC) is a frequent and deadly disease worldwide. The absence of effective therapies when the tumor is surgically unresectable leads to an extremely poor outcome of HCC patients. Thus, it is mandatory to elucidate the molecular pathogenesis of HCC in order to develop novel therapeutic strategies against this pernicious tumor. Mounting evidence indicates that suppression of the DNA damage response machinery might be deleterious for the survival and growth of the tumor cells. In particular, DNA dependent protein kinase catalytic subunit (DNA-PKcs), a major player in the non-homologous end-joining (NHEJ) repair process, seems to represent a valuable target for innovative anti-neoplastic therapies in cancer. DNA-PKcs levels are strongly upregulated and associated with a poor clinical outcome in various tumor types, including HCC. Importantly, DNA-PKcs not only protects tumor cells from harmful DNA insults coming either from the microenvironment or chemotherapeutic drug treatments, but also possesses additional properties, independent from its DNA repair activity, that provide growth advantages to cancer cells. These properties (metabolic and gene reprogramming, invasiveness and metastasis, resistance to apoptosis, etc.) have started to be elucidated. In the present review, we summarize the physiologic and oncogenic roles of DNA-PKcs, with a special emphasis on liver cancer. In particular, this work focuses on the molecular mechanism whereby DNA-PKcs exerts its pro-tumorigenic activity in cancer cells. In addition, the upstream regulator of DNA-PKcs activation as well as its downstream effectors thus far identified are illustrated. Furthermore, the potential therapeutic strategies aimed at inhibiting DNA-PKcs activity in HCC are discussed.

Oldenlandia diffusa Promotes Antiproliferative and Apoptotic Effects in a Rat Hepatocellular Carcinoma with Liver Cirrhosis

Oldenlandia diffusa (OD) is commonly used with various diseases such as cancer, arthritis, and autoimmune disease. Liver cirrhosis is a predominant risk factor for hepatocellular carcinoma (HCC). Here, we show that the therapeutic effect of OD, which was investigated both in vitro and chemically, induced HCC model. OD significantly enhanced apoptosis and antiproliferative activity and reduced migration ability of HCC cells. In vivo, OD was treated twice a day for 28 days after confirmed HCC model through 2-[¹⁸F]-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) imaging. The survival in OD treated groups was shown to have a greater therapeutic effect than the control group. 28 days after OD treatment, OD treated groups resulted in a significant reduction in tumor number, size, ¹⁸F-FDG uptake, and serum levels such as alanine transaminase, aspartate transaminase, and alkaline phosphate compared to the control group. Also, proliferated cells in tumor sites by OD were reduced compared to the control group. Furthermore, several rats in OD treated group survived over 60 days and liver morphology of these rats showed the difference between tumor mass and normal tissue. These results suggest that OD may have antiproliferative activity, inhibition of metastasis, and apoptotic effects in chemically induced HCC model and can have the potential use for clinical application as anticancer drug of the herbal extract.

Silencing ADAM10 inhibits the in vitro and in vivo growth of hepatocellular carcinoma cancer cells

A disintegrin and metalloprotease 10 (ADAM10) is a transmembrane protein associated with metastasis in a number of types of cancer. Little is known, however, regarding the role of ADAM10 in hepatocellular carcinoma (HCC). The aim of the present study was to evaluate whether downregulation of ADAM10 effects HCC cell proliferation, cell cycle, cell migration and cell invasion. A recombinant small hairpin RNA expression vector carrying ADAM10 was constructed and then transfected into the HepG2 human HCC cell line. In vitro cell proliferation, cell cycle, cell migration and cell invasion, and in vivo tumor growth were determined following the downregulation of ADAM10 by RNA interference. The results revealed that downregulation of ADAM10 expression in HepG2 tumor cells using the RNA silencing approach significantly suppressed cell proliferation, cell migration and cell invasion in vitro, and tumor growth in vivo. Furthermore, ADAM10 silencing was able to significantly reduce constitutive phosphorylation of phosphoinositide 3-kinase (PI3K) and Akt, which implies that ADAM10 is, at least partially, involved in the activation of the PI3K/Akt signaling pathway. These results suggest that ADAM10 is important in regulating the proliferation and metastasis of HCC. Thus, ADAM10 is a promising therapeutic target for the prevention of tumor metastases in HCC.

Silencing of the glypican-3 gene affects the biological behavior of human hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death in the world. The gene glypican-3 (GPC3) is reported to be a potential therapeutic target for HCC. In this study, we use RNA interference with lentiviral vectors to explore the effect of GPC3 silencing on the biological behavior of HCC cells and the potential role of the GPC3 protein in the activation of epithelial-mesenchymal transition (EMT), which relates to HCC cell invasion and migration. Our data suggest that GPC3 silencing leads to a decrease in HCC cell proliferation and to an increase in apoptosis. We demonstrated that GPC3 silencing regulates cell invasion and migration, most probably through the activation of the EMT cellular program. In conclusion, GPC3 is associated with the HCC cell biological behavior, while the relationship between GPC3 and EMT in tumorigenesis of HCC deserves future investigation.

Sox17 inhibits hepatocellular carcinoma progression by downregulation of KIF14 expression

Sox17, an antagonist of canonical Wnt/β-catenin signaling, inhibits several malignant carcinogenesis and progression. However, little is known about Sox17 in hepatocellular carcinoma (HCC). Here, we found that Sox17 is downregulated in HCC tissue. Furthermore, Sox17 inhibits cell proliferation and migration in HCC. KIF14, a member of kinesin superfamily protein (KIFs), is an oncogene in a variety of malignant tumors including HCC. We demonstrated that Sox17 is negatively related to KIF14 expression in HCC tissue and Sox17 inhibits HCC cell proliferation and migration by transcriptional downregulation of KIF14 expression. Our results may provide a strategy for blocking HCC carcinogenesis and progression.

Role of hepatitis C virus induced osteopontin in epithelial to mesenchymal transition, migration and invasion of hepatocytes

Osteopontin (OPN) is a secreted phosphoprotein which has been linked to tumor progression and metastasis in a variety of cancers including hepatocellular carcinoma (HCC). Previous studies have shown that OPN is upregulated during liver injury and inflammation. However, the role of OPN in hepatitis C virus (HCV)-induced liver disease pathogenesis is not known. In this study, we determined the induction of OPN, and then investigated the effect of secreted forms of OPN in epithelial to mesenchymal transition (EMT), migration and invasion of hepatocytes. We show the induction of OPN mRNA and protein expression by HCV-infection. Our results also demonstrate the processing of precursor OPN (75 kDa) into 55 kDa, 42 kDa and 36 kDa forms of OPN in HCV-infected cells. Furthermore, we show the binding of secreted OPN to integrin αVβ3 and CD44 at the cell surface, leading to the activation of downstream cellular kinases such as focal adhesion kinase (FAK), Src, and Akt. Importantly, our results show the reduced expression of epithelial marker (E-cadherin) and induction of mesenchymal marker (N-cadherin) in HCV-infected cells. We also show the migration and invasion of HCV-infected cells using wound healing assay and matrigel coated Boyden chamber. In addition, we demonstrate the activation of above EMT markers, and the critical players involved in OPN-mediated cell signaling cascade using primary human hepatocytes infected with Japanese fulminant hepatitis (JFH)-1 HCV. Taken together, these studies suggest a potential role of OPN in inducing chronic liver disease and HCC associated with chronic HCV infection.

Mechanism of hepatitis C virus (HCV)-induced osteopontin and its role in epithelial to mesenchymal transition of hepatocytes

Osteopontin (OPN) is a secreted phosphoprotein, originally characterized in malignant-transformed epithelial cells. OPN is associated with tumor metastasis of several tumors and is overexpressed in hepatocellular carcinoma (HCC) tissue involving HCC invasion and metastasis. Importantly, OPN is significantly up-regulated in liver injury, inflammation, and hepatitis C virus (HCV)-associated HCC. However, the underlying mechanisms of OPN activation and its role in HCV-mediated liver disease pathogenesis are not known. In this study, we investigated the mechanism of OPN activation in HCV-infected cells. We demonstrate that HCV-mediated Ca(2+) signaling, elevation of reactive oxygen species, and activation of cellular kinases such as p38 MAPK, JNK, PI3K, and MEK1/2 are involved in OPN activation. Incubation of HCV-infected cells with the inhibitors of AP-1 and Sp1 and site-directed mutagenesis of AP-1- and Sp1-binding sites on the OPN promoter suggest the critical role of AP-1 and Sp1 in OPN promoter activation. In addition, we show the in vivo interactions of AP-1 and Sp1 with the OPN promoter using chromatin immunoprecipitation assay. We also show the calpain-mediated processing of precursor OPN (∼75 kDa) into ∼55-, ∼42-, and ∼36-kDa forms of OPN in HCV-infected cells. Furthermore, we demonstrate the critical role of HCV-induced OPN in increased phosphorylation of Akt and GSK-3β followed by the activation of β-catenin, which can lead to EMT of hepatocytes. Taken together, these studies provide an insight into the mechanisms of OPN activation that is relevant to the metastasis of HCV-associated HCC.

Deregulation of signalling pathways in prognostic subtypes of hepatocellular carcinoma: novel insights from interspecies comparison

Hepatocellular carcinoma is a frequent and fatal disease. Recent researches on rodent models and human hepatocarcinogenesis contributed to unravel the molecular mechanisms of hepatocellular carcinoma dedifferentiation and progression, and allowed the discovery of several alterations underlying the deregulation of cell cycle and signalling pathways. This review provides an interpretive analysis of the results of these studies. Mounting evidence emphasises the role of up-regulation of RAS/ERK, P13K/AKT, IKK/NF-kB, WNT, TGF-ß, NOTCH, Hedgehog, and Hippo signalling pathways as well as of aberrant proteasomal activity in hepatocarcinogenesis. Signalling deregulation often occurs in preneoplastic stages of rodent and human hepatocarcinogenesis and progressively increases in carcinomas, being most pronounced in more aggressive tumours. Numerous changes in signalling cascades are involved in the deregulation of carbohydrate, lipid, and methionine metabolism, which play a role in the maintenance of the transformed phenotype. Recent studies on the role of microRNAs in signalling deregulation, and on the interplay between signalling pathways led to crucial achievements in the knowledge of the network of signalling cascades, essential for the development of adjuvant therapies of liver cancer. Furthermore, the analysis of the mechanisms involved in signalling deregulation allowed the identification of numerous putative prognostic markers and novel therapeutic targets of specific hepatocellular carcinoma subtypes associated with different biologic and clinical features. This is of prime importance for the selection of patient subgroups that are most likely to obtain clinical benefit and, hence, for successful development of targeted therapies for liver cancer.

DNA repair capacity, DNA-strand break repair gene polymorphisms, and the incidence of hepatocellular carcinoma in southwestern Guangxi of China

The associations between DNA repair capacity (DRC), DNA repair gene polymorphisms, and the incidence of hepatocellular carcinoma (HCC) have not been determined in high-risk areas. The aims of this study were to investigate whether DRC is related to the incidence of HCC and to determine whether polymorphisms in the DNA repair genes that regulate DRC are associated with the risk of HCC. First, a small case-control study was conducted to examine the association between DRC and the incidence of HCC and the environmental and genetic factors regulating DRC. Then, a large case-control study was conducted to determine whether those DNA repair gene polymorphisms shown to regulate DRC were related to the risk of HCC. The median DRC was significantly lower among the cases (0.80) than the controls (0.93). A multivariate linear regression analysis showed that the HBsAg status (p<0.01), ethnicity (p=0.01), and polymorphisms in the XRCC3-241 (p=0.01) and APE1-148 (p=0.03) gene loci may be impact factors for DRC. In the large case-control study, a stratified analysis showed that individuals with the APE1-148-combined genotype GT+TT likely had a significantly higher HCC risk compared with those with only the GG genotype (crude odds ratio=1.93, 95% confidence interval=1.17-3.17) among the Zhuang ethnicity. However, nonsignificant differences were observed between XRCC3-241 polymorphisms and the HCC risk. DRC may be related to the incidence of HCC as determined by environmental and genetic factors found in southwestern part of the Guangxi Province. Gene-environment interactions play an important role in the incidence and progression of HCC.

Ethanol Extract of Dianthus chinensis L. Induces Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells In Vitro

Dianthus chinensis L. is used to treat various diseases including cancer; however, the molecular mechanism by which the ethanol extract of Dianthus chinensis L. (EDCL) induces apoptosis is unknown. In this study, the apoptotic effects of EDCL were investigated in human HepG2 hepatocellular carcinoma cells. Treatment with EDCL significantly inhibited cell growth in a concentration- and time-dependent manner by inducing apoptosis. This induction was associated with chromatin condensation, activation of caspases, and cleavage of poly (ADP-ribose) polymerase protein. However, apoptosis induced by EDCL was attenuated by caspase inhibitor, indicating an important role for caspases in EDCL responses. Furthermore, EDCL did not alter the expression of bax in HepG2 cells but did selectively downregulate the expression of bcl-2 and bcl-xl, resulting in an increase in the ratio of bax:bcl-2 and bax:bcl-xl. These results support a mechanism whereby EDCL induces apoptosis through the mitochondrial pathway and caspase activation in HepG2 cells.

Growth inhibition of human hepatocellular carcinoma cells by overexpression of G-protein-coupled receptor kinase 2

Hepatocellular carcinoma (HCC) is one of the deadliest forms of human liver cancer and does not respond well to conventional therapies. Novel effective treatments are urgently in need. G-protein-coupled kinase 2 (GRK2) is unique serine/threonine kinase that involves in many signaling pathways and regulates various essential cellular processes. Altered levels of GRK2 have been linked with several human diseases including cancer. In this study, we investigated a novel approach for HCC treatment by inducing overexpression of GRK2 in human HCC cells. We found that overexpression of GRK2 through recombinant adenovirus transduction inhibits the growth of human HCC cells. BrdU incorporation assay showed that the growth inhibition caused by elevated GRK2 level was due to reduced cell proliferation but not apoptosis. To examine the anti-proliferative function of increased GRK2 level, we performed cell cycle analysis using propidium iodide staining. We found that the proliferation suppression was associated with G2/M phase cell cycle arrest by the wild-type GRK2 but not its kinase-dead K220R mutant. Furthermore, increased levels of wild-type GRK2 induced upregulation of phosphor-Ser(15) p53 and cyclin B1 in a dose-dependent manner. Our data indicate that the anti-proliferative function of elevated GRK2 is associated with delayed cell cycle progression and is GRK2 kinase activity-dependent. Enforced expression of GRK2 in human HCC by molecular delivery may offer a potential therapeutic approach for the treatment of human liver cancer.

Silencing glypican-3 expression induces apoptosis in human hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the most common internal malignant tumors. Glypican-3 (GPC3) is involved in the biological and molecular events in the tumorigenesis of HCC. We used RNA interference to evaluate the molecular effects of GPC3 suppression at the translational level and demonstrated for the first time that GPC3 silencing results in a significant elevation of the Bax/Bcl-2 ratio, the release of cytochrome c from mitochondria and the activation of caspase-3. The results suggest that GPC3 regulates cell proliferation by enhancing the resistance to apoptosis through the dysfunction of the Bax/Bcl-2/cytochrome c/caspase-3 signaling pathway and therefore plays a critical role in the tumorigenesis of HCC. Thus, the knockdown of GPC3 should be further investigated as an attractive novel approach for the targeted gene therapy of HCC.

Automatic transwell assay by an EIS cell chip to monitor cell migration

Here an EIS (electrochemical impedance spectroscopy) biochip to detect cell migration is demonstrated. This biochip has been inspired by a traditional transwell assay/modified Boyden chamber and consists of two compartments separated by a porous membrane. This structure (PDMS-based) is aligned to EIS sensors. Cells are seeded in the upper chamber through microfluidic channels. During migration cells go through the pores of the membrane and get in touch with the electrodes that detect migrated cells. The performance of our cell-chip was tested by investigating the migratory ability of hepatocellular carcinoma (HCC) cells as a function of microenvironment. For this purpose we challenged HCC cells to migrate on different extra-cellular matrix (ECM) components including laminin 1, collagen IV and laminin 5. The results reveal that our cell chip provides reliable results that consistently overlap with those obtained with traditional standardized Boyden chambers. Thus, we demonstrate a new, easy tool to study cell migration and to perform automatic assays. This approach is easier and faster than traditional transwell assays and can be suitable for high-throughput studies in drug discovery applications.

γ-Tocotrienol is a novel inhibitor of constitutive and inducible STAT3 signalling pathway in human hepatocellular carcinoma: potential role as an antiproliferative, pro-apoptotic and chemosensitizing agent

BACKGROUND AND PURPOSE

Activation of signal transducer and activator of transcription 3 (STAT3) play a critical role in the survival, proliferation, angiogenesis and chemoresistance of tumour cells. Thus, agents that suppress STAT3 phosphorylation have potential as cancer therapies. In the present study, we investigated whether the apoptotic, antiproliferative and chemosensitizing effects of γ-tocotrienol are associated with its ability to suppress STAT3 activation in hepatocellular carcinoma (HCC).

EXPERIMENTAL APPROACH

The effect of γ-tocotrienol on STAT3 activation, associated protein kinases and phosphatase, STAT3-regulated gene products, cellular proliferation and apoptosis in HCC cells was investigated.

KEY RESULTS

γ-Tocotrienol inhibited both the constitutive and inducible activation of STAT3 with minimum effect on STAT5. γ-Tocotrienol also inhibited the activation of Src, JAK1 and JAK2 implicated in STAT3 activation. Pervanadate reversed the γ-tocotrienol-induced down-regulation of STAT3, suggesting the involvement of a protein tyrosine phosphatase. Indeed, we found that γ-tocotrienol induced the expression of the tyrosine phosphatase SHP-1 and deletion of the SHP-1 gene by small interfering RNA abolished the ability of γ-tocotrienol to inhibit STAT3 activation. γ-Tocotrienol also down-regulated the expression of STAT3-regulated gene products, including cyclin D1, Bcl-2, Bcl-xL, survivin, Mcl-1 and vascular endothelial growth factor. Finally, γ-tocotrienol inhibited proliferation, induced apoptosis and significantly potentiated the apoptotic effects of chemotherapeutic drugs (paclitaxel and doxorubicin) used for the treatment of HCC.

CONCLUSIONS AND IMPLICATIONS

Overall, these results suggest that γ-tocotrienol is a novel blocker of the STAT3 activation pathway, with a potential role in future therapies for HCC and other cancers.

Signaling networks in human hepatocarcinogenesis--novel aspects and therapeutic options

Hepatocellular carcinoma (HCC) represents one of the most common human malignancies with poor prognosis. Because therapeutic strategies are insufficient for most HCC patients, there is a great need to determine the central molecular mechanisms and pathways in order to derive novel targets for systemic therapy. There is vast evidence that not only the dysregulation of distinct signaling cascades, but also their interactions at different levels, affect tumor cell function. Through these interactions, the effects of pathways can be increased, and even new tumor-supporting qualities acquired that further facilitate HCC progression. Although several approaches for the modulation of these relevant pathways are under development, future therapeutic strategies should take into account that oncogenic stimuli cannot be understood in a monodimensional manner. In order to avoid escape mechanisms during therapy, strategies based on comprehensive knowledge of the interactive regulatory network in hepatocarcinogenesis are necessary.

Oncogenetic tree modeling of human hepatocarcinogenesis

Classical comparative genomic hybridization (CGH) has been used to identify recurrent genomic alterations in human HCC. As hepatocarcinogenesis is considered as a stepwise process, we applied oncogenetic tree modeling on all available classical CGH data to determine occurrence of genetic alterations over time. Nine losses (1p, 4q, 6q, 8p, 9p, 13q, 16p, 16q and 17p) and ten gains (1q, 5p, 6p, 7p, 7q, 8q, 17q, 20p, 20q and Xq) of genomic information were used to build the oncogenetic tree model. Whereas gains of 1q and 8q together with losses of 8p formed a cluster that represents early etiology-independent alterations, the associations of gains at 6q and 17q as well as losses of 6p and 9p were observed during tumor progression. HBV-induced HCCs had significantly more chromosomal aberrations compared to HBV-negative tumors. Losses of 1p, 4q and 13q were associated with HBV-induced HCCs, whereas virus-negative HCCs showed an association of gains at 5p, 7, 20q and Xq. Using five aberrations that were significantly associated with tumor dedifferentiation a robust progression model of stepwise human hepatocarcinogensis (gain 1q → gain 8q → loss 4q → loss 16q → loss 13q) was developed. In silico analysis revealed that protumorigenic candidate genes have been identified for each recurrently altered hotspot. Thus, oncogenic candidate genes that are coded on chromosome arms 1q and 8q are promising targets for the prevention of malignant transformation and the development of biomarkers for the early diagnosis of human HCC that may significantly improve the treatment options and thus prognosis of HCC patients.

The 4-acetylantroquinonol B isolated from mycelium of Antrodia cinnamomea inhibits proliferation of hepatoma cells

BACKGROUND

Antrodia cinnamomea is known for its antihepatoma activity, yet the identity of its active compound was unclear. In this study, a 5-ton fermenter was used to prepare sufficient mycelium of A. cinnamomea for active compound isolation and identification.

RESULTS

Using antiproliferative activity toward HepG2 cells as guidance in the isolation process, 4-acetylantroquinonol B was purified and identified to be the major bioactive compound of A. cinnamomea cultivated by submerged fermentation. The median effective doses (EC(50)) of 4-acetylantroquinonol B for HepG2 cells were 0.10 +/- 0.00 and 0.08 +/- 0.00 microg mL(-1) for 72 and 96 h treatments, respectively. The selective indices of 4-acetylantroquinonol B were 100 and 125 for 72 and 96 h treatments, respectively, indicating that this compound had high selective activity for hepatoma cells.

CONCLUSION

4-Acetylantroquinonol B is the major antihepatoma constituent of Antrodia cinnamomea mycelium produced by submerged fermentation.

Soluble glypican 3 inhibits the growth of hepatocellular carcinoma in vitro and in vivo

The heterogeneity of the molecular pathology of HCC poses a formidable obstacle to the development of non-cytotoxic therapies. Several pro-tumorigenic signaling pathways can be aberrantly activated in HCC, including those triggered by Wnts. Glypican-3 (GPC3), a membrane-bound heparan sulfate proteoglycan that is overexpressed in most HCCs, promotes the growth of these tumors by stimulating Wnt signaling. Because GPC3 binds with high affinity to Wnts, and its growth-promoting activity requires attachment to the cell membrane, we have hypothesized that a mutated GPC3 lacking the GPI anchoring domain (sGPC3) will block Wnt signaling and inhibit the growth of Wnt-dependent tumors. In addition, because sGPC3 displays heparan sulfate chains, this secreted glypican could also inhibit HCC growth by blocking the activity of other heparin-binding growth factors. To test this hypothesis, HCC cell lines were infected with an sGPC3-expressing lentivirus or virus control, and the effect of sGPC3 on the in vitro and in vivo growth was investigated. In addition, the signaling pathways targeted by sGPC3 were identified. We observed that sGPC3-expressing cells had lower proliferation rate. In addition, sGPC3 significantly inhibited the in vivo growth of the Huh6, HepG2 and Huh7 HCC cell lines. sGPC3 blocked Wnt signaling in Huh6- and Huh7-derived tumors and Erk1/2 and Akt phosphorylation in tumors generated by Huh7 and HepG2 cells, respectively. An anti-angiogenic effect in Huh7 and HepG2-derived tumors was also observed. We conclude that sGPC3 can inhibit HCC tumorigenicity by blocking the activity of several pro-tumorigenic growth factors.

Prognostic markers and putative therapeutic targets for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most frequent human cancer and a fatal disease. Therapies with pharmacological agents do not improve the prognosis of patients with unresectable HCC. This emphasizes the need to identify new targets for early diagnosis, chemoprevention, and treatment of the disease. Available evidence indicates that clinical outcome of HCC could reflect the genetic predisposition to cancer development and progression. Numerous loci controlling HCC progression have been identified in rodents. In this review, we describe results of recent studies on effector mechanisms of susceptibility/resistance genes, responsible for HCC progression, aimed at identifying new putative prognostic markers and therapeutic targets of this tumor. Highest c-myc amplification and overexpression, alterations of iNOS crosstalk with IKK/NF-kB and RAS/ERK signaling, ubiquitination of ERK and cell cycle inhibitors, and deregulation of FOXM1 and cell cycle key genes occur in rapidly progressing dysplastic nodules and HCC, induced in genetic susceptible rat strains, compared to the lesions of resistant rats. Notably, alterations of these mechanisms in human HCC subtypes with poorer or better prognosis, are similar to those present in genetically susceptible and resistant rats, respectively, and function as prognostic markers and therapeutic targets. Attempts to cure advanced HCC by molecular therapy directed against specific targets led to modest survival benefit. Thus, efforts are necessary to identify and test, in pre-clinical and clinical studies, new therapeutic targets for combined molecular treatments of HCC. They may take advantage from the comparative analysis of signal transduction in HCCs differently prone to progress, in rats and humans.

Overexpression of VCC-1 gene in human hepatocellular carcinoma cells promotes cell proliferation and invasion

Vascular endothelial growth factor-correlated chemokine 1 (VCC-1), a novel chemokine, is hypothesized to be associated with carcinogenesis. VCC-1 is expressed in hepatocellular carcinoma (HCC) cells, but its function remains unknown. To investigate the molecular effects of VCC-1 on HCC cells, the HCC cell line SMMC7721 was stably transfected with the recombinant plasmid pcDNA3.1/VCC-1. Our data demonstrated that overexpression of VCC-1 in SMMC7721 cells significantly enhanced the cellular proliferation, invasive ability, and tumor growth, when compared with both empty vector control cells and parental cells. These results strongly suggest that VCC-1 plays an important role in SMMC7721 invasion and tumor growth, and indicate that VCC-1 may serve as a potential biomarker for anti-HCC therapies.

Targeting heat shock protein 90 with non-quinone inhibitors: a novel chemotherapeutic approach in human hepatocellular carcinoma

The inhibition of heat shock protein 90 (Hsp90) has emerged as a promising antineoplastic strategy in diverse human malignancies. Hsp90 has been predicted to be involved in hepatocellular carcinoma (HCC) development; however, its role in hepatocarcinogenesis remains elusive. Using chemically distinctive Hsp90 inhibitors, we show that Hsp90 capacitates the aberrant expression and activity of crucial hepatocarcinogenesis-driving factors (e.g., insulin-like growth factor receptor 1, hepatocyte growth factor receptor, protein kinase B, v-raf-1 murine leukemia viral oncogene homolog 1, and cyclin-dependent kinase 4). In vitro, Hsp90 inhibition with both geldanamycin analogs (17-allylamino-17-desmethoxygeldanamycin (17-AAG) and 17-dimethylaminoethylamino-17-desmethoxygeldanamycin (17-DMAG)) and the non-quinone compound 8-(6-iodobenzo[d][1,3]dioxol-5-ylthio)-9-(3-(isopropylamino)propyl)-9H-purin-6-amine (PU-H71) reduced the viability of various HCC cell lines, induced the simultaneous degradation of numerous hepatocarcinogenic factors, and caused substantial cell cycle arrest and apoptosis. In contrast, nontumorigenic hepatocytes were less susceptible to Hsp90 inhibition. Because conventional geldanamycin-derivate Hsp90 inhibitors induce dose-limiting liver toxicity, we tested whether novel Hsp90 inhibitors lacking the benzoquinone moiety, which has been deemed responsible for hepatotoxicity, can elicit antineoplastic activity without causing significant liver damage. In HCC xenograft mouse models, PU-H71 was retained in tumors at pharmacologically relevant concentrations while being rapidly cleared from nontumorous liver. PU-H71 showed potent and prolonged in vivo Hsp90 inhibitory activity and reduced tumor growth without causing toxicity.

CONCLUSION

Hsp90 constitutes a promising therapeutic target in HCC. Non-quinone Hsp90 inhibitors exhibit tumor-specific accumulation and exert potent antineoplastic activity without causing significant hepatotoxicity.

Proinflammatory cytokines cause FAT10 upregulation in cancers of liver and colon

The mRNA of the ubiquitin-like modifier FAT10 has been reported to be overexpressed in 90% of hepatocellular carcinoma (HCC) and in over 80% of colon, ovary and uterus carcinomas. Elevated FAT10 expression in malignancies was attributed to transcriptional upregulation upon the loss of p53. Moreover, FAT10 induced chromosome instability in long-term in vitro culture, which led to the hypothesis that FAT10 might be involved in carcinogenesis. In this study we show that interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha synergistically upregulated FAT10 expression in liver and colon cancer cells 10- to 100-fold. Real-time RT-PCR revealed that FAT10 mRNA was significantly overexpressed in 37 of 51 (72%) of human HCC samples and in 8 of 15 (53%) of human colon carcinomas. The FAT10 cDNA sequences in HCC samples were not mutated and intact FAT10 protein was detectable. FAT10 expression in both cancer tissues correlated with expression of the IFN-gamma- and TNF-alpha-dependent proteasome subunit LMP2 strongly suggesting that proinflammatory cytokines caused the joint overexpression of FAT10 and LMP2. NIH3T3 transformation assays revealed that FAT10 had no transforming capability. Taken together, FAT10 qualifies as a marker for an interferon response in HCC and colon carcinoma but is not significantly overexpressed in cancers lacking a proinflammatory environment.

[Molecular pathogenesis of hepatocellular carcinoma: new therapeutic approaches and predictive pathology]

Hepatocellular carcinoma is one of the most prevalent malignancies worldwide and its incidence is increasing. Multimodal strategies directed towards this carcinoma include primary (e.g. immunisation) and secondary (e.g. antiviral therapy) prevention, surgical approaches, novel specific systemic therapies (targeted therapy), and the treatment of comorbidity (cirrhosis). New molecular approaches are currently under development. These tackle several specific targets, with pathology being challenged in many aspects: experimental evaluation, the development of valid tumor-relevant diagnostic tests as well as morphological evaluation in the context of clinical studies, and finally in routine diagnosis.

Differential expression of E-prostanoid receptors in human hepatocellular carcinoma

Recent studies have shown that inhibition of cyclooxygenases (e.g. COX-2) exerts antitumorigenic effects on hepatocellular carcinomas (HCCs), which are to a significant extent due to the abrogation of PGE(2) synthesis. PGE(2) acts via differentially regulated prostaglandin receptors (EP(1-4)). Our study was designed to investigate the expression pattern of EP-receptors in HCCs and to evaluate the therapeutic potential of selective EP-receptor antagonists. Using tissue microarrays including a total of 14 control livers, 17 liver cirrhoses, 22 premalignant dysplastic nodules (DNs) and 162 HCCs with different histological grades, the expression of COX-2, mPGES-1 and -2 and EP(1-4)-receptors was analyzed. Western immunoblot analyses were performed to confirm the expression in HCC cell lines. The effects of EP(1-4)-receptor antagonism on cell viability and apoptosis were investigated using MTT-assays and FACS-analyses, respectively. COX-2, mPGES-1 and -2 and EP(1-4)-receptors were expressed in all HCC tissues. COX-2 expression was highest in DNs and declined with loss of HCC-differentiation. With respect to COX-2 expression, a converse expression of EP(1-3) -receptors and mPGES-1 and -2 was found in DNs compared to HCCs. Selectively antagonizing EP(1)- and EP(3)-receptors reduced the viability of HCC cells in a dose-dependent manner, which was associated with apoptosis induction. Our results suggest a differential regulation of EP-receptor subtype expression with dedifferentiation of HCCs in which a converse expression pattern for COX-2 in comparison to EP(1-3)-receptors occurs. Of clinical interest, selectively antagonizing EP(1)- and EP(3)-receptors may provide a novel systemic therapeutic approach to the treatment of HCCs.

Quantitative analysis of gene expression relative to 18S rRNA in carcinoma samples using the LightCycler instrument and a SYBR GreenI-based assay: determining FAT10 mRNA levels in hepatocellular carcinoma

Due to the fact that mutations and up- or downregulation of genes can lead to the development of cancer, quantitative comparison of relative gene expression in healthy and cancerous tissue can gain valuable insights into tumorigenesis. While the semi-quantitative DNA microarrays are being used to identify differentially expressed genes on a genomic scale, real-time RT-PCR provides a powerful tool for quantitative measurement of gene expression. Presently, it is the most sensitive method available. Here we describe in detail a SYBR GreenI-based assay using the LightCycler instrument to measure the levels of mRNA for the ubiquitin-like protein FAT10 relative to 18S rRNA in human hepatocellular carcinoma tissue. This method can be easily adapted to any tissue (human or mouse, rat, etc.) and any gene.

Protumorigenic overexpression of stathmin/Op18 by gain-of-function mutation in p53 in human hepatocarcinogenesis

The microtubule (MT)-destabilizing protein stathmin/Op18 has previously been described to be negatively regulated by p53 and to be highly expressed in several tumor entities. However, little is known about its expression profile, functional or therapeutic relevance, and regulation in human hepatocarcinogenesis. Here we demonstrate cytoplasmic overexpression of stathmin in premalignant lesions (dysplastic nodules; DNs) and hepatocellular carcinomas (HCCs), which significantly correlated with tumor progression, proliferation, and activation of other protumorigenic factors (e.g., nuclear p53). Inhibition of stathmin expression by gene-specific short interfering RNA (siRNA) was associated with a significant reduction of MT-dependent cellular functions such as tumor cell viability, proliferation, migration, and increased apoptosis in HCC cells. Loss of stathmin expression increased responsiveness of tumor cells to the treatment with cytostatic drugs targeting MT-stability (paclitaxel, vinblastine) and to DNA cross-linking agents (cisplatin). Surprisingly, inducible expression of p53(wt) in p53-negative HCC cells as well as a reduction of p53(wt) by siRNA in p53(wt)-positive cells did not alter stathmin expression. However, stathmin was down-regulated after siRNA-based reduction of p53(mut/Y220C) and p53(mut/R213Q) expression in different tumor cell types.

CONCLUSION

Our results demonstrate that overexpression of stathmin is an early protumorigenic event in human hepatocarcinogenesis, and its up-regulation can be mediated by gain-of-function mutations in p53. Thus, stathmin represents a potential therapeutic target, for example, by increasing responsiveness of tumor cells to treatment with chemotherapeutic agents after reduction of stathmin bioactivity.

Cyclooxygenase-2 Inhibition Induces Apoptosis Signaling via Death Receptors and Mitochondria in Hepatocellular Carcinoma

Inhibition of cyclooxygenase (COX)-2 elicits chemopreventive and therapeutic effects in solid tumors that are coupled with the induction of apoptosis in tumor cells. We investigated the mechanisms by which COX-2 inhibition induces apoptosis in hepatocellular carcinoma (HCC) cells. COX-2 inhibition triggered expression of the CD95, tumor necrosis factor (TNF)-R, and TNF-related apoptosis-inducing ligand (TRAIL)-R1 and TRAIL-R2 death receptors. Addition of the respective specific ligands further increased apoptosis, indicating that COX-2 inhibition induced the expression of functional death receptors. Overexpression of a dominant-negative Fas-associated death domain mutant reduced COX-2 inhibitor-mediated apoptosis. Furthermore, our findings showed a link between COX-2 inhibition and the mitochondrial apoptosis pathway. COX-2 inhibition led to a rapid down-regulation of myeloid cell leukemia-1 (Mcl-1), an antiapoptotic member of the Bcl-2 family, followed by translocation of Bax to mitochondria and cytochrome c release from mitochondria. Consequently, overexpression of Mcl-1 led to inhibition of COX-2 inhibitor-mediated apoptosis. Furthermore, blocking endogenous Mcl-1 function using a small-interfering RNA approach enhanced COX-2 inhibitor-mediated apoptosis. It is of clinical importance that celecoxib acted synergistically with chemotherapeutic drugs in the induction of apoptosis in HCC cells. The clinical relevance of these results is further substantiated by the finding that COX-2 inhibitors did not sensitize primary human hepatocytes toward chemotherapy-induced apoptosis. In conclusion, COX-2 inhibition engages different apoptosis pathways in HCC cells stimulating death receptor signaling, activation of caspases, and apoptosis originating from mitochondria.

Apoptotic effects of Antrodia cinnamomea fruiting bodies extract are mediated through calcium and calpain-dependent pathways in Hep 3B cells

Antrodia cinnamomea is well known in Taiwan as a traditional medicine for treating cancer and inflammation. The purpose of this study was to evaluate the apoptotic effects of ethylacetate extract from A. cinnamomea (EAC) fruiting bodies in Hep 3B, a liver cancer cell line. EAC decreased cell proliferation of Hep 3B cells by inducing apoptotic cell death. EAC treatment increased the level of calcium (Ca2+) in the cytoplasm and triggered the subsequent activation of calpain and caspase-12. EAC also initiated the mitochondrial apoptotic pathway through regulation of Bcl-2 family proteins expression, release of cytochrome c, and activation of caspase-9 in Hep 3B cells. Furthermore, the mitochondrial apoptotic pathway amplified the calpain pathway by Bid and Bax interaction and Ca2+ translocation. We have therefore concluded that the molecular mechanisms during EAC-mediated proliferation inhibition in Hep 3B cells were due to: (1) apoptosis induction, (2) triggering of Ca2+/calpain pathway, (3) disruption of mitochondrial function, and (4) apoptotic signaling being amplified by cross-talk between the calpain/Bid/Bax and Ca2+/mitochondrial apoptotic pathways.

Doxorubicin coupled to lactosaminated albumin inhibits the growth of hepatocellular carcinomas induced in rats by diethylnitrosamine

BACKGROUND/AIMS

The hepatocyte receptor for asialoglycoproteins internalizes galactosyl terminating macromolecules which can be used as hepatotropic drug carriers. Since this receptor is also expressed on the cells of well differentiated human hepatocellular carcinomas (HCCs), we studied whether conjugation of doxorubicin (DOXO) with lactosaminated human albumin (L-HSA) increases the drug efficacy on HCCs induced in rats by diethylnitrosamine (DENA).

METHODS

DENA was given in the drinking water for 8 weeks. One week after the last day of DENA administration, animals were randomly assigned to three groups. Each group was administered with either saline, free or coupled DOXO (1 microg/g). Rats received 4 weekly intravenous injections. One week after the last administration, rats were killed and HCC development was evaluated by counting the tumor nodules on the surface of hepatic lobes.

RESULTS

In rats treated with L-HSA coupled DOXO the number of neoplastic nodules was significantly lower (P < 0.05) than that counted in animals injected with saline or with free DOXO. Coupled DOXO did not decrease body rat weight, which was markedly reduced by the free drug.

CONCLUSIONS

Conjugation with L-HSA increased the antineoplastic efficacy and decreased the systemic toxicity of DOXO administered to rats with HCCs produced by DENA.

Glypican-3 promotes the growth of hepatocellular carcinoma by stimulating canonical Wnt signaling

Glypican-3 (GPC3) is a heparan sulfate proteoglycan that is bound to the cell membrane by a glycosyl-phosphatidylinositol anchor. GPC3 is expressed by most hepatocellular carcinomas but not by normal hepatocytes and benign liver lesions. We report here that GPC3 stimulates the in vitro and in vivo growth of hepatocellular carcinoma cells by increasing autocrine/paracrine canonical Wnt signaling. Co-immunoprecipitation experiments showed that GPC3 is able to form complexes with Wnts, and cell-binding assays indicated that GPC3-expressing cells have an increased capacity to bind Wnt. Collectively, these results suggest that GPC3 stimulates Wnt activity by facilitating the interaction of this polypeptide with its signaling receptors. Surprisingly, in contrast to the current model that proposes that Wnt-glypican binding is mediated by the heparan sulfate chains, we found that the nonglycanated GPC3 core protein can form complexes with Wnts. Furthermore, we showed that the glycosaminoglycan chains are not required for the stimulatory effect on Wnt signaling and hepatocellular carcinoma growth.

Apoptotic effects of extract from Antrodia camphorata fruiting bodies in human hepatocellular carcinoma cell lines

The fruiting body of Antrodia camphorata is well known in Taiwan as a traditional medicine for treating cancer and inflammation. The purpose of this study was to evaluate the apoptotic effects of ethylacetate extract from A. camphorata (EAC) fruiting bodies in two human liver cancer cell lines, Hep G2 and PLC/PRF/5. Treatment with EAC decreased the cell growth of Hep G2 and PLC/PRF/5 cells in a dose dependent manner. In Fas/APO-1 positive-Hep G2 cells, EAC increased the expression level of Fas/APO-1 and its two forms of ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), in a p53-indenpendent manner. In addition, EAC also initiated mitochondrial apoptotic pathway through regulation of Bcl-2 family proteins expression, release of cytochrome c, and activation of caspase-9 both in Hep G2 and PLC/PRF/5 cells. Furthermore, EAC also inhibited the cell survival signaling by enhancing the amount of IkappaBalpha in cytoplasm and reducing the level and activity of NF-kappaB in the nucleus, and subsequently attenuated the expression of Bcl-X(L) in Hep G2 and PLC/PRF/5 cells. EAC therefore decreased the cell growth and induced apoptosis both in Hep G2 and PLC/PRF/5 cells.

Chromosome alterations in human hepatocellular carcinomas correlate with aetiology and histological grade--results of an explorative CGH meta-analysis

All available comparative genomic hybridisation (CGH) analyses (n=31, until 12/2003) of human hepatocellular carcinomas (HCCs; n=785) and premalignant dysplastic nodules (DNs; n=30) were compiled and correlated with clinical and histological parameters. The most prominent amplifications of genomic material were present in 1q (57.1%), 8q (46.6%), 6p (22.3%), and 17q (22.2%), while losses were most prevalent in 8p (38%), 16q (35.9%), 4q (34.3%), 17p (32.1%), and 13q (26.2%). Deletions of 4q, 16q, 13q, and 8p positively correlated with hepatitis B virus aetiology, while losses of 8p were more frequently found in hepatitis C virus-negative cases. In poorly differentiated HCCs, 13q and 4q were significantly under-represented. Moreover, gains of 1q were positively correlated with the occurrence of all other high-frequency alterations in HCCs. In DNs, amplifications were most frequently present in 1q and 8q, while deletions occurred in 8p, 17p, 5p, 13q, 14q, and 16q. In conclusion, aetiology and dedifferentiation correlate with specific genomic alterations in human HCCs. Gains of 1q appear to be rather early events that may predispose to further chromosomal abnormalities. Thus, explorative CGH meta-analysis generates novel and testable hypotheses regarding the cause and functional significance of genomic alterations in human HCCs.

Molecular profiling of human hepatocellular carcinoma defines mutually exclusive interferon regulation and insulin-like growth factor II overexpression

Molecular subtyping of human hepatocellular carcinoma (HCC) with potential mechanistic and therapeutic impact has not been achieved thus far. We have analyzed the mRNA expression patterns of 43 different human HCC samples and 3 HCC cell lines in comparison with normal adult liver using high-density cDNA microarrays. Two main groups of HCC, designated group A (65%) and group B (35%), were distinguished based on clustering of the most highly varying genes. Group A HCCs were characterized by induction of a number of interferon (IFN)-regulated genes, whereas group B was characterized mainly by down-regulation of several apoptosis-relevant and IFN-regulated genes. The number of apoptotic tumor cells and tumor-infiltrating lymphocytes was significantly higher in tumors of group A as compared with those of group B. Based on the expression pattern, group B was further subdivided into two subgroups, designated subgroup B1 (6 of 43 tumors, 14%) and subgroup B2 (9 of 43 tumors, 21%). A prominent characteristic of subgroup B1 was high overexpression of insulin-like growth factor (IGF)-II. All tested HCC cell lines expressed equally high concentrations of IGF-II transcripts and co-segregated with group B1 in clustering. IGF-II overexpression and induction of IFN-related genes were mutually exclusive, even when analysis was extended to other cancer expression profile studies. Moreover, IFN-gamma treatment substantially reduced IGF-II expression in HCC cells. In conclusion, cDNA microarray analyses provided subtyping of HCCs that is related to intratumor inflammation and tumor cell apoptosis. This profiling may be of mechanistic and therapeutic impact because IGF-II overexpression has been linked to reduced apoptosis and increased proliferation and may be accessible to therapeutic intervention.

Different procarcinogenic potentials of lymphocyte subsets in a transgenic mouse model of chronic hepatitis B

The immune response to hepatitis viruses is believed to be involved in the development of chronic hepatitis; however, its pathogenetic potential has not been clearly defined. The current study, using a transgenic mouse model of chronic hepatitis B, was designed to determine the relative contributions of the immune cell subsets to the progression of liver disease that induces hepatocellular carcinogenesis. Hepatitis B virus transgenic mice were adoptively transferred with CD4+ and CD8+ T cell-enriched or -depleted and B cell-depleted splenocytes obtained from hepatitis B surface antigen-primed, syngeneic nontransgenic donors. The resultant liver disease, hepatocyte apoptosis, regeneration, and tumor development were assessed and compared with the manifestations in mice that had received unfractionated spleen cells. Transfer of CD8(+)-enriched splenocytes caused prolonged disease kinetics, and a marked increase in the extent of hepatocyte apoptosis and regeneration. In 12 of 14 mice the transfer resulted in multiple hepatocellular carcinomas (HCCs) comparable with the manifestations seen in the mice transferred with total splenocytes. In contrast, mice that had received CD4(+)-enriched cells demonstrated lower levels of liver disease and developed fewer incidences of HCC (4 of 17). The experiment also revealed that all of the groups of mice complicated with HCC developed comparable mean numbers and sizes of tumors. B-cell depletion had no effect on disease kinetics in this model. Taken together, these results demonstrate that the pathogenetic events induced by CD8+ T-cell subset are primarily responsible for the induction of chronic liver disease that increases tumor incidence, suggesting their potential in triggering the process of hepatocarcinogenesis.

Acacetin inhibits the proliferation of Hep G2 by blocking cell cycle progression and inducing apoptosis

Flavonoids are a broadly distributed class of plant pigments, universally present in vascular plants and responsible for much of the coloring in nature. They are strong antioxidants that occur naturally in foods and can inhibit carcinogenesis in rodents. In this study, we examined acacetin (5,7-dihydroxy-4'-methoxyflavone), a flavonoid compound, for its effect on proliferation in a human liver cancer cell line, Hep G2. The results showed that acacetin inhibited the proliferation of Hep G2 by inducing apoptosis and blocking cell cycle progression in the G1 phase. Enzyme-linked immunosorbent assay showed that acacetin significantly increased the expression of p53 and p21/WAF1 protein, contributing to cell cycle arrest. An enhancement in Fas/APO-1 and its two form ligands, membrane-bound Fas ligand and soluble Fas ligand, as well as Bax protein, was responsible for the apoptotic effect induced by acacetin. Taken together, our study suggests that the induction of p53 and activity of the Fas/Fas ligand apoptotic system may participate in the antiproliferative activity of acacetin in Hep G2 cells.