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Background: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality. We previously showed that the inhibition of placental growth factor (PlGF) exerts antitumour effects and induces vessel normalisation, possibly reducing hypoxia. However, the exact mechanism underlying these effects remains unclear. Because hypoxia and endoplasmic reticulum stress, which activates the unfolded protein response (UPR), have been implicated in HCC progression, we assessed the interactions between PlGF and these microenvironmental stresses. Methods: PlGF knockout mice and validated monoclonal anti-PlGF antibodies were used in a diethylnitrosamine-induced mouse model for HCC. We examined the interactions among hypoxia, UPR activation and PlGF induction in HCC cells. Results: Both the genetic and pharmacological inhibitions of PlGF reduced the chaperone levels and the activation of the PKR-like endoplasmic reticulum kinase (PERK) pathway of the UPR in diethylnitrosamine-induced HCC. Furthermore, we identified that tumour hypoxia was attenuated, as shown by reduced pimonidazole binding. Interestingly, hypoxic exposure markedly activated the PERK pathway in HCC cells in vitro, suggesting that PlGF inhibition may diminish PERK activation by improving oxygen delivery. We also found that PlGF expression is upregulated by different chemical UPR inducers via activation of the inositol-requiring enzyme 1 pathway in HCC cells. Conclusions: PlGF inhibition attenuates PERK activation, likely by tempering hypoxia in HCC via vessel normalisation. The UPR, in turn, is able to regulate PlGF expression, suggesting the existence of a feedback mechanism for hypoxia-mediated UPR that promotes the expression of the angiogenic factor PlGF. These findings have important implications for our understanding of the effect of therapies normalising tumour vasculature. [ABSTRACT FROM AUTHOR]

Background & Aims: Expression of liver progenitor cell (LPC) characteristics has been proposed as a negative prognostic marker in primary liver tumors. Hypoxia has been linked to activation of the Notch pathway which is responsible for activation and proliferation of LPCs and hypoxia-induced LPC activation has been shown in hepatocellular carcinoma. Our aim was to elucidate the time-dependent effects of hypoxia on the LPC niche in hepatocellular carcinoma which could aid in determining a safe time frame for use of hypoxia inducing therapies. Methods: We used dimethyloxaloylglycine to mimic a hypoxic reaction in mice by stabilizing hypoxia-inducible factor 1 alpha at three distinct time points in diethylnitrosamine induced hepatocarcinogenesis. LPC, metastasis and Notch pathway markers were determined by quantitative PCR and (immune)histochemistry (heamatoxillin-eosin, reticulin, Sirius red and cytokeratin 19 staining). Results: Activating the hypoxia inducible pathway early in hepatocarcinogenesis resulted in an increased incidence of both cholangioma and hepatocellular lesions, associated with high expression of LPC, metastatic and Notch pathway markers. Adversely, activating the hypoxic response during tumor development resulted in decreased incidence of hepatocellular lesions and increased cholangioma incidence, with an unaltered gene expression profile of LPC-, Notch pathway- and metastatic markers. A hypoxic insult at advanced stages of hepatocarcinogenesis severely increased the expression of LPC characteristics, however without increased expression of actors of the Notch pathway and metastatic markers and minor changes in incidence of hepatocellular and cholangioma lesions. Conclusion: Our results indicate that increased hypoxia at the onset of tumor development has detrimental effects on tumor progression; patients with HCC developed in a background of fibrosis/cirrhosis might therefore represent a more difficult treatment group. In contrast, hypoxia during tumor development appears to favor tumor outcome, highlighting the importance of early detection. Finally, hypoxia in advanced stages resulted in increased expression of LPC characteristics indicating poor outcome. [ABSTRACT FROM AUTHOR]

Fanconi anemia ( FA) is an inherited bone marrow failure syndrome due to defective DNA inter-strand cross-link repair. Hematopoietic stem cell transplantation ( HSCT) is curative for pancytopenia, but may not prevent the development of non-hematological malignancies. We describe a 26-year-old male patient with FA and Marfan syndrome who in 1994 underwent successful HSCT with bone marrow stem cells from his human leukocyte antigen ( HLA)-identical sister. In 2006, three lesions in the liver were detected and resected. The three lesions all showed activation of the β-catenin pathway and were histologically characterized by a highly differentiated steatotic hepatocellular carcinoma ( HCC) with remnants of the underlying adenoma from which it arose, a hepatocellular adenoma with foci of well-differentiated HCC, and a cholestatic adenoma. Risk factors for the emergence of HCC included FA itself, the use of androgens for a period of 3 years preceding HSCT and toxicity of the conditioning regimen. Because of the danger of developing additional HCC, liver transplantation was proposed, taking into consideration that immunosuppression would increase the risk of other malignancies. By using part of the liver of the sister, who already acted as bone marrow donor 13 years earlier, immunosuppression could be avoided. Liver transplantation was performed in 2007 without complication. Five years after liver transplantation the patient is doing well. This case is twofold special being the first case reporting FA co-occurring with Marfan syndrome and being the first reported case of FA treated for HCC by liver transplantation from a HLA-identical sibling donor without the use of immunosuppression. [ABSTRACT FROM AUTHOR]

Abstract: Background: Non-alcoholic fatty liver disease is a spectrum of disorders ranging from steatosis to non-alcoholic steatohepatitis (NASH). Steatosis of the liver is benign, whereas NASH can progress to cirrhosis or even hepatocellular carcinoma. Currently, a liver biopsy is the only validated method to distinct NASH from steatosis. Aim: The objective of this study was to identify a biomarker specific for NASH based on the N-glycosylation of serum proteins. Methods: N-glycosylation patterns were assessed using DNA sequencer-assisted fluorophore-assisted capillary electrophoresis and compared with histology. Results: Initially, a glycomarker (log[NGA2F]/[NA2]) was developed based on the results obtained in 51 obese non-alcoholic patients scheduled for bariatric surgery. Multivariate analysis showed that our glycomarker had the lowest P-value of all biomarkers in distinguishing NASH from steatosis (P =0.069). The glycomarker was validated in a cohort of 224 non-alcoholic fatty liver disease patients. In both pilot and validation study, glycomarker score increased in ascending amount of lobular inflammation (single-factor ANOVA, P ≤0.001 and P =0.012, respectively). The N-glycan profile of immunoglobulin G in the NASH population confirmed the significantly increased undergalactosylation present in these patients. Conclusion: Our glycomarker specifically recognises liver inflammation in obese individuals which is the main trigger for the development of steatohepatitis and can differentiate between steatosis and NASH. [Copyright &y& Elsevier]

Background: The increasing incidence of hepatocellular carcinoma in Western countries has led to an expanding interest of scientific research in this field. Therefore, a vast need of experimental models that mimic the natural pathogenesis of hepatocellular carcinoma (HCC) in a short time period is present. The goal of our study was (1) to develop an efficient mouse model for HCC research, in which tumours develop in a natural background of fibrosis and (2) to assess the time-dependent angiogenic changes in the pathogenesis of HCC. Methods: Weekly intraperitoneal injections with the hepatocarcinogenic compound N-nitrosodiethylamine was applied as induction method and samples were taken at several time points to assess the angiogenic changes during the progression of HCC. Results: The N-nitrosodiethylamine-induced mouse model provides well vascularised orthotopic tumours after 25 weeks. It is a representative model for human HCC and can serve as an excellent platform for the development of new therapeutic targets. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) responds poorly to chemotherapy owing to multidrug resistance (MDR). Recent studies showed that part of HCC could be of progenitor cell origin. Because some MDR-conferring transporters [multidrug resistance-associated protein 1 (MRP1), MDR1, MRP3 and breast cancer resistance protein (BCRP)] are expressed in hepatic progenitor cells (HPCs), expression in HCC might reflect a progenitor cell origin and provide the tumour cells with a MDR phenotype. Methods: The transcriptional profile of transporter genes was assessed in 139 HCCs earlier subjected to global gene expression analysis. In addition, we performed real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry for MRP1, MRP3, MDR1, BCRP and biliary/HPC markers keratin 7 and/or keratin 19 (K7/K19) on an independent set of 23 HCCs and surrounding liver. Results: Micro-array analysis showed that MRP1 was the only transporter with increased mRNA levels in HCC compared with the surrounding tissue. MRP1 mRNA levels were significantly higher in HCCs with poor survival and the ‘hepatoblast subtype’ of HCC, thought to be derived from HPCs. In 11 of 23 HCCs of the independent set, we found a diffuse protein expression of MRP1 compared with negative hepatocytic expression observed in normal (surrounding) hepatocytes. MRP1 was expressed in K19+ non-neoplastic HPCs and K19+ tumour cells. In addition, MRP3 and BCRP were expressed in K7/K19+ tumour cells. MRP1 expression was high in poorly differentiated HCCs, large tumours (>7 cm) and microvascular invasive tumours. Conclusions: MRP1 correlated with K19 mRNA and protein expression in two independent series of HCC. In addition, MRP1 was, together with MRP3 and BCRP, colocalized with K7/K19 in the tumour. Therefore, MRP1 expression could be a reflection of the HPC origin of this subgroup of HCCs and may result in an aggressive tumour phenotype. [ABSTRACT FROM AUTHOR]

The variability in the prognosis of individuals with hepatocellular carcinoma (HCC) suggests that HCC may comprise several distinct biological phenotypes. These phenotypes may result from activation of different oncogenic pathways during tumorigenesis and/or from a different cell of origin. Here we address whether the transcriptional characteristics of HCC can provide insight into the cellular origin of the tumor. We integrated gene expression data from rat fetal hepatoblasts and adult hepatocytes with HCC from human and mouse models. Individuals with HCC who shared a gene expression pattern with fetal hepatoblasts had a poor prognosis. The gene expression program that distinguished this subtype from other types of HCC included markers of hepatic oval cells, suggesting that HCC of this subtype may arise from hepatic progenitor cells. Analyses of gene networks showed that activation of AP-1 transcription factors in this newly identified HCC subtype might have key roles in tumor development. [ABSTRACT FROM AUTHOR]

Libbrecht L, Desmet V, Roskams T. Preneoplastic lesions in human hepatocarcinogenesis.Liver International 2005: 25: 16–27.© Blackwell Munksgaard, 2005The early stages of hepatocarcinogenesis in human chronic liver diseases are characterized by the emergence of preneoplastic lesions of which some will eventually develop into hepatocellular carcinoma (HCC). Basic studies on the genetic and epigenetic alterations of these preneoplastic lesions may eventually lead to new therapeutic strategies. Clinicopathological studies are also important in order to determine optimal management of patients with a preneoplastic lesion. This article aims to provide a comprehensive review of the current concepts of preneoplastic lesion in chronic liver diseases. The microscopical small-cell dysplastic focus is the smallest morphologically recognizable precursor lesion of HCC and therefore is a logical target of study to elucidate the earliest events in hepatocarcinogenesis. In contrast, large-cell dysplasia is not a precursor lesion, but appears to be of clinical value because of its good predictive value for development of HCC. Dysplastic nodules (DNs) are macroscopically recognizable precursor lesions of HCC and high-grade DNs (HGDNs) have a risk of malignant transformation. Detection of DNs and correct differentiation from small HCC (<2 cm) is sometimes difficult, especially when only imaging techniques are used. Additional clinicopathological studies on identification and optimal treatment of DNs are necessary. Molecular studies on HGDNs and small HCCs may yield much information on the genetic mechanisms involved in the transition from severe dysplasia to early malignancy. In contrast, currently available data indicate that (large) regenerative nodules do not represent a distinct step in hepatocarcinogenesis. Animal models will be helpful in the further unravelling of human HCC development, provided that studies are performed on models that are good representatives of human hepatocarcinogenesis. We propose three criteria by which good mimickers can be identified. [ABSTRACT FROM AUTHOR]

The article discusses the role of Glypican-3 (GPC3) in solid pseudopapillary neoplasm (SPN) of the pancreas. It notes that GPC3 is a cell-surface protein that regulates the Wnt-signalling pathway and is highly expressed in hepatocellular carcinoma (HCC). It mentions that GPC3 functions as a tumour suppressor gene and an oncofetal protein in some tissues and is also expressed in various embryonal tumours. It reveals that the pancreatic SPN is associated with pancreatic development.

Background & Aims: Hepatocellular adenomas (HCA) are benign liver tumors mainly related to oral contraception and classified into 4 molecular subgroups: inflammatory (IHCA), HNF1A-inactivated (H-HCA), β-catenin-activated (bHCA) or unclassified (UHCA). Glycogen storage disease type I (GSD) is a rare hereditary metabolic disease that predisposes to HCA development. The aim of our study was to characterize the molecular profile of GSD-associated HCA. Methods: We characterized a series of 25 HCAs developed in 15 patients with GSD by gene expression and DNA sequence of HNF1A, CTNNB1, IL6ST, GNAS, and STAT3 genes. Moreover, we searched for glycolysis, gluconeogenesis, and fatty acid synthesis alterations in GSD non-tumor livers and compared our results to those observed in a series of sporadic H-HCA and various non-GSD liver samples. Results: GSD adenomas were classified as IHCA (52%) mutated for IL6ST or GNAS, bHCA (28%) or UHCA (20%). In contrast, no HNF1A inactivation was observed, showing a different molecular subtype distribution in GSD-associated HCA from that observed in sporadic HCA (p= 0.0008). In non-tumor GSD liver samples, we identified glycolysis and fatty acid synthesis activation with gluconeogenesis repression. Interestingly, this gene expression profile was similar to that observed in sporadic H-HCA. Conclusions: Our study showed a particular molecular profile in GSD-related HCA characterized by a lack of HNF1A inactivation. This exclusion could be explained by similar metabolic defects observed with HNF1A inactivation and glucose-6-phosphatase deficiency. Inversely, the high frequency of β-catenin mutations could be related to the increased frequency of malignant transformation in hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]

Background & Aims: The placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family known to stimulate endothelial cell growth, migration and survival, attract angiocompetent macrophages, and determine the metastatic niche. Unlike VEGF, genetic studies have shown that PlGF is specifically involved in pathologic angiogenesis, thus its inhibition would not affect healthy blood vessels, providing an attractive drug candidate with a good safety profile. Methods: We assess whether inhibition of PlGF could be used as a potential therapy against hepatocellular carcinoma (HCC), by using PlGF knockout mice and monoclonal anti-PlGF antibodies in a mouse model for HCC. In addition, the effect of PlGF antibodies is compared to that of sorafenib, as well as the combination of both therapies. Results: We have found that both in a transgenic knockout model and in a treatment model, targeting PlGF significantly decreases tumor burden. This was achieved not only by inhibiting neovascularisation, but also by decreasing hepatic macrophage recruitment and by normalising the remaining blood vessels, thereby decreasing hypoxia and reducing the prometastatic potential of HCC. Conclusions: Considering the favourable safety profile and its pleiotropic effect on vascularisation, metastasis and inflammation, PlGF inhibition could become a valuable therapeutic strategy against HCC. [ABSTRACT FROM AUTHOR]

Background & Aims: The two major primary liver cancers in adults are hepatocellular carcinoma and cholangiocarcinoma. These tumors rapidly outgrow their vascular supply and become hypoxic, resulting in the production of hypoxia inducible factors. Recently, interest has grown in the regulators of these factors. Several reports have been published describing the role of prolyl hydroxylase domains – the key oxygen sensor responsible for the degradation of hypoxia inducible factors – in tumor progression and vascularisation. The effect of prolyl hydroxylase domain 2 on the pathogenesis of liver cancer has never been studied. Methods: A diethylnitrosamine-induced mouse model was used in this study, allowing primary hepatic tumors to occur as a result of chronic liver damage. Several parameters of prolyl hydroxylase domain 2-haplodeficient mice were compared to those of wild type mice, thereby focussing on the expression of angiogenic factors and on the hepatic progenitor cell activation and differentiation. Results: This study shows that inhibiting prolyl hydroxylase domain 2 increases the hepatocarcinogenesis and stimulates the development of cholangiocarcinoma. Furthermore, PHD2 deficiency and the accompanying continuous HIF activation, selected for a more metastatic tumor phenotype. Conclusions: The effect of prolyl hydroxylase domain 2 deficiency on hepatocarcinogenesis hold a great potential for therapeutic intervention, since hypoxia and the selection for a more aggressive cholangiocarcinoma phenotype might also have a repercussion on patients receiving long-term treatment with anti-angiogenic compounds. [Copyright &y& Elsevier]