Emerging drugs for hepatocellular carcinoma

Targeted Therapies for Hepatocellular Carcinoma Treatment: A New Era Ahead-A Systematic Review

Hepatocellular carcinoma (HCC) remains one of the most common malignancies and the third cause of cancer-related death worldwide, with surgery being the best prognostic tool. Among the well-known causative factors of HCC are chronic liver virus infections, chronic virus hepatitis B (HBV) and chronic hepatitis virus C (HCV), aflatoxins, tobacco consumption, and non-alcoholic liver disease (NAFLD). There is a need for the development of efficient molecular markers and alternative therapeutic targets of great significance. In this review, we describe the general characteristics of HCC and present a variety of targeted therapies that resulted in progress in HCC therapy.

γ-Glutamylcysteine synthetase (γ-GCS) as a target for overcoming chemo- and radio-resistance of human hepatocellular carcinoma cells

AIMS

This study uncovered that the genetically endowed intracellular glutathione contents (iGSH) regulated by the catalytic subunit of γ‑glutamylcysteine synthetase heavy chain (γ‑GCSh) as a prime target for overcoming both the inherited and stimuli-activated chemo- and radio-resistance of hepatocellular carcinoma (HCC) cells.

MAIN METHODS

Reactive oxygen species (ROS) production and mitochondrial membrane potential (Δψm) were determined by the probe-based flow cytometry. The TUNEL assay was used as an index of radio-sensitivity and the MTT assay was used as an index of chemo-sensitivity against various anti-cancer agents. iGSH and γ‑GCSh activity were measured by HPLC methods. γ‑GCSh-overexpressing GCS30 cell line was established by tetracycline-controlled Tet-OFF gene expression system in SK-Hep-1 cells.

KEY FINDINGS

The relative radio-sensitivities of a panel of five HCC cells were found to be correlated negatively with both the contents of iGSH and their corresponding γ‑GCSh activities with an order of abundance being Hep G2 > Hep 3B > J5 > Mahlavu > SK-Hep-1, respectively. Similarly, the cytotoxicity response patterns of these HCC cells against arsenic trioxide (ATO), a ROS-producing anti-cancer drug, were exactly identical to the order of ranking instigated by the radiotherapy (RT) treatment. Next, γ‑GCSh-overexpressing GCS30 cells were found to possess excellent ability to profoundly mitigate both the drop of Δψm and apoptotic TUNEL-positive cell population engendered by ATO, cisplatin, doxorubicin, and RT treatments.

SIGNIFICANCE

Our data unequivocally demonstrate that γ‑GCSh may represent a prime target for overcoming anti-cancer drugs and RT resistance for HCC cells.

Gamma-irradiated β-glucan modulates signaling molecular targets of hepatocellular carcinoma in rats

β-glucans are one of the most abundant forms of polysaccharides known as biological response modifiers which influence host's biological response and stimulate immune system. Accordingly, this study was initiated to evaluate irradiated β-glucan as a modulator for cellular signaling growth factors involved in the pathogenesis of hepatocellular carcinoma in rats. Hepatocellular carcinoma was induced with 20 mg diethylnitrosamine/kg BW. Rats received daily by gastric gavage 65 mg irradiated β-glucan/kg BW. It was found that treatment of rats with diethylnitrosamine induced hepatic injury and caused significant increase in liver injury markers with a concomitant significant increase in both hepatic oxidative and inflammatory indices: alpha-fetoprotein, interferon gamma, and interleukin 6 in comparison with normal and irradiated β-glucan-treated groups. Western immunoblotting showed a significant increase in the signaling growth factors: extracellular signal-regulated kinase 1 and phosphoinositide 3-kinase proteins in a diethylnitrosamine-treated group while both preventive and therapeutic irradiated β-glucan treatments recorded significant improvement versus diethylnitrosamine group via the modulation of growth factors that encounters hepatic toxicity. The transcript levels of vascular endothelial growth factor A and inducible nitric oxide synthase genes were significantly higher in the diethylnitrosamine-treated group in comparison with controls. Preventive and therapeutic treatments with irradiated β-glucan demonstrated that the transcript level of these genes was significantly decreased which demonstrates the protective effect of β-glucan. Histological investigations revealed that diethylnitrosamine treatment affects the hepatic architecture throughout the significant severe appearance of inflammatory cell infiltration in the portal area and congestion in the portal vein in association with severe degeneration and dysplasia in hepatocytes all over hepatic parenchyma. The severity of hepatic architecture changes was significantly decreased with both β-glucan therapeutic and preventive treatments. In conclusion, irradiated β-glucan modulated signal growth factors, vascular endothelial growth factor A, extracellular signal-regulated kinase 1, and phosphatidylinositol-3-kinase, which contributed to experimental hepatocarcinogenesis.

Berberine regulates the protein expression of multiple tumorigenesis-related genes in hepatocellular carcinoma cell lines

Background

Hepatocellular carcinoma (HCC) is the seventh most common malignancy and the third leading cause of cancer-related death worldwide with an extremely grim prognosis. Berberine (BBR) has been found to inhibit proliferation of human HCC cells, although the underlying mechanism(s) are unclear.

Methods

Protein expression was detected by Western blots. Cell viability was determined by using the CellTiter Assay kit.

Results

We confirm that BBR treatment inhibits HepG2, Hep3B, and SNU-182 cell viability, and suggest that it regulates this proliferation via the modulation of multiple tumorigenesis-related genes protein expression. BBR treatment up-regulated protein expression of tumor suppressor genes, including Kruppel-like factor 6 (KLF6), activating transcription factor 3 (ATF3) and p21, while down-regulating the expression of selected oncogenes, including E2F transcription factor 1 (E2F1) and pituitary tumor transforming gene 1 (PTTG1). The specific extracellular signal–regulated kinases 1/2 (ERK1/2) inhibitor, PD98059, partially inhibited BBR effects including reduction of cell viability, and up-regulation of KLF6 and ATF3 expressions; although, PD98059 did not alter the down-regulation of E2F1 and PTTG1 expression by BBR.

Conclusions

Our results suggest that BBR inhibits HCC cell viability by modulating multiple tumorigenesis-related genes, and that up-regulation of tumor suppressor genes by BBR is in part the result of ERK1/2 action. The results of this study augment our understanding of the mechanisms underlying the effect of BBR on hepatocellular cancers and provide further evidence as to the biological plausibility of this agent’s role in the treatment of these malignancies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-017-0429-3) contains supplementary material, which is available to authorized users.

Suppressing the CDC37 cochaperone in hepatocellular carcinoma cells inhibits cell cycle progression and cell growth

BACKGROUND & AIMS

The molecular cochaperone CDC37 regulates the activities of multiple protein kinases, and is an attractive broad-spectrum target in many types of cancers in which it is over-expressed. This study investigates the antitumour effects of inhibiting CDC37 in human hepatocellular carcinoma (HCC).

METHODS

A total of 91 patients were enrolled for CDC37 mRNA detection by using quantitative real-time PCR. Cell proliferation, gene expression changes and tumourigenicity were determined by targeting CDC37 using RNA interference in human hepatoma cell lines.

RESULTS

We confirmed the significant over-expression of CDC37 transcript and protein in HBV-associated HCC patients. Using a CDC37-specific small oligo-siRNA, we silenced CDC37 expression in HepG2 and Huh7 hepatoma cell lines, and observed inhibition of in vitro cell proliferation, cell cycle arrest at the G1 phase, and enhanced apoptosis. Specifically, we found concomitant down-regulation of Cyclin D1, CDK4, and pRB (S807/811 and S795) upon CDC37 suppression, which could mediate the arrest of cell cycle progression at the G1 phase. Gene expression profiling further identified several genes involved in cell proliferation, cell cycle progression, and apoptosis that are regulated by CDC37 suppression. Huh7 cells with stable knockdown of CDC37 showed decreased in vitro colony formation ability, and significantly slowed xenograft growth in vivo.

CONCLUSIONS

On the basis of the observed antitumour effects of inhibiting CDC37 expression, we propose that CDC37 is a promising therapeutic target in HCC. Its ability to regulate multiple pathways makes it potentially valuable in treating the heterogeneous subtypes of this malignancy.

Dual PI3K/mTOR inhibitor NVP-BEZ235-induced apoptosis of hepatocellular carcinoma cell lines is enhanced by inhibitors of autophagy

Dysregulation of the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling has been found in several types of human cancer, including hepatocellular carcinoma (HCC). NVP-BEZ235 is a novel, orally bioavailable dual PI3K/mTOR inhibitor that has exhibited promising activity against HCC in preclinical models. Autophagy is a cellular lysosomal degradation pathway essential for the regulation of cell survival and death to maintain homeostasis. This process is negatively regulated by mTOR signaling and often counteracts the efficacy of certain cancer therapeutic agents. In this study, we explored the role of autophagy in apoptosis induced by NVP-BEZ235 in two HCC cell lines, Hep3B and PLC/PRF/5, and identified the mechanism of combinatorial treatment. NVP-BEZ235 was effective in inhibiting the growth of the two HCC cell lines possibly though induction of apoptosis. NVP-BEZ235 also potently increased the expression of LC3-II and decreased the expression of p62, indicating induction of autophagy. When NVP-BEZ235 was used in combination with Atg5 siRNA or the autophagy inhibitor 3-methyladenine (3-MA), enhancement of the inhibitory effects on the growth of HCC cells was detected. In addition, enhanced induction of apoptosis was observed in cells exposed to the combination of NVP-BEZ235 and Atg5 siRNA or 3-MA. Thus, induction of autophagy by NVP-BEZ235 may be a survival mechanism that counteracts its anticancer effects. Based on these data, we suggest a strategy to enhance the anticancer efficacy of BEZ235 by blockade of autophagy. Thus, our study provides a rationale for the clinical development of combinations of NVP-BEZ235 and autophagy inhibitors for the treatment of HCC and other malignancies.

Targeted agents and systemic therapy in hepatocellular carcinoma

Cytotoxic chemotherapy, hormonal agents, and immunotherapy have been tested in hepatocellular cancer (HCC) with marginal efficacy to date. Recent insights into the molecular pathogenesis of HCC have identified several aberrant signaling pathways that have served as targets for novel therapeutic agents. These discoveries have been translated into the clinical realm with the use of the antiangiogenic and the Raf kinase inhibitor, sorafenib, and have revealed the potential of targeted agents to produce clinically meaningful survival benefits in patients with advanced HCC. Efforts continue in the quest to improve the outcome of HCC patients through the development and evaluation of other targeted agents, and to better understand the interactions between the underlying disease biology and response to therapy. Several pathways are now implicated in hepatocarcinogenesis and agents that target these pathways continue to be developed.

CD147/EMMPRIN: an effective therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is characterized by high resistance to conventional systemic therapies, rapid progression, easy metastasis and frequent recurrence. There is therefore an urgent requirement to develop novel systemic agents which specifically target hepatoma-associated antigen in the tumors of HCC patients. CD147, a transmembrane glycoprotein, is highly expressed by HCC cells and is strongly associated with HCC progression and prognosis. CD147 in HCC cells modulates HCC growth, promotes invasion and metastasis by stimulating adjacent fibroblasts and HCC cells to produce elevated levels of several extracellular matrix metalloproteinases (MMPs) in the HCC microenvironment. It is also involved in HCC angiogenesis and multidrug resistance (MDR). Clinical progress has been made in HCC treatment using CD147-directed monoclonal antibodies. Here, we give an overview of the literature regarding the molecular features and expression of CD147 in human HCC tissues. We specifically focus on the role of CD147 in HCC invasion and metastasis, as well as in angiogenesis and multidrug resistance. In addition, advances in therapeutic strategies targeting HCC CD147 are summarized.

Glycosylated diazeniumdiolate-based oleanolic acid derivatives: synthesis, in vitro and in vivo biological evaluation as anti-human hepatocellular carcinoma agents

A series of O(2)-glycosylated diazeniumdiolate-based derivatives of oleanolic acid (4-19) were synthesized and their anti-human hepatocellular carcinoma (HCC) activities were evaluated. Compound 6 selectively inhibited HCC, but not non-tumor liver cell proliferation. This inhibition was attributed to high levels of nitric oxide (NO) released in HCC cells. Importantly, 6 exhibited low acute toxicity (LD(50) = 173.3 mg kg(-1)) and potent inhibition of HCC tumor growth in mice (3 mg kg(-1) iv). Furthermore, 6 induced HCC cell apoptosis, which was accompanied by lower mitochondrial membrane potentials and Bcl2 expression, but with higher cytochrome C release, Bax, caspase 3 and 9 expression activities in HCC cells. Collectively, 6 may be a promising candidate drug for the intervention of HCC.

A triterpenoid from Thalictrum fortunei induces apoptosis in BEL-7402 cells through the P53-induced apoptosis pathway

Thalictrum fortunei S. Moore, a perennial plant distributed in the southeastern part of China, has been used in Traditional Chinese Medicine for thousands of years for its antitumor, antibacterial and immunoregulatory effects. In order to investigate the active components and the mechanism of the anti-tumor effects of Thalictrum fortunei, the growth inhibitory effects of eight triterpenoids isolated from the aerial parts of the plant on tumor cell lines were examined by 3-(4,5)-dimethylthiazoy1-3,5-diphenyltetrazolium bromide (MTT) assay. The MTT-assay results showed that the inhibitory activity of 3-O-β-d-glucopyranosyl-(1→4)-β-d-fucopyranosyl(22S,24Z)-cycloart-24-en-3β,22,26-triol 26-O-β-d-glucopyranoside (1) was stronger than that of the other seven tested triterpenoids on human hepatoma Bel-7402 cell line (Bel-7402), human colon lovo cells (LoVo), human non-small cells lung cancer NCIH-460 cells (NCIH-460) and human gastric carcinoma SGC-7901 cells (SGC-7901) after 48 h treatment in vitro, with the IC₅₀ values of 66.4, 84.8, 73.5, 89.6 μM, respectively. Moreover, the antitumor mechanism of compound 1 on Bel-7402 cell was explored through nucleus dyeing, fluorescence assay, flow cytometry and western blot. The flow cytometric analysis results revealed that compound 1 caused apoptosis and mitochondrial membrane potential (MMP) loss in Bel-7402 cells. A fluorescence assay indicated that intracellular reactive oxygen species (ROS) were markedly provoked by compound 1 treatment compared to control cells. Immunoblot results showed that compound 1 significantly increased the expression levels of cleaved caspase-3, P53 and Bax protein, and decreased the expression level of Bcl-2 protein. These findings indicate that compound 1 inhibits the growth activity of tumor cells, probably through the P53 protein-induced apoptosis pathway.

Berberine induces cell death in human hepatoma cells in vitro by downregulating CD147

The isoquinoline plant alkaloid berberine has anti-tumor effects on a variety of carcinoma cells, mainly through inhibition of cell proliferation, apoptosis induction and cell cycle arrest. However, the mechanisms underlying its role in tumor progression are unknown. In the present study, we investigated the molecular mechanisms involved in berberine-induced cell death in human hepatoma carcinoma cell (HCC) lines HepG2 and SMMC7721. Our results showed that berberine inhibited tumor cell viability in a dose- and time-dependent manner, and induced cell death via apoptosis and autophagy. Moreover, berberine treatment significantly inhibited CD147 expression by HCC cells in a dose-dependent manner. Overexpression of CD147 protein markedly reduced berberine-induced cell death. Our data provide the first experimental evidence that berberine induces cell death in HCC cells via downregulation of CD147 and suggest a new mechanism to explain its anti-tumor effects.

Novel therapeutic strategies for targeting liver cancer stem cells

The cancer stem cell (CSC) hypothesis was first proposed over 40 years ago. Advances in CSC isolation were first achieved in hematological malignancies, with the first CSC demonstrated in acute myeloid leukemia. However, using similar strategies and technologies, and taking advantage of available surface markers, CSCs have been more recently demonstrated in a growing range of epithelial and other solid organ malignancies, suggesting that the majority of malignancies are dependent on such a compartment.

Primary liver cancer consists predominantly of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). It is believed that hepatic progenitor cells (HPCs) could be the origin of some HCCs and ICCs. Furthermore, stem cell activators such as Wnt/β-catenin, TGF-β, Notch and Hedgehog signaling pathways also expedite tumorigenesis, and these pathways could serve as molecular targets to assist in designing cancer prevention strategies. Recent studies indicate that additional factors such as EpCAM, Lin28 or miR-181 may also contribute to HCC progression by targeting HCC CSCs. Various therapeutic drugs that directly modulate CSCs have been examined in vivo and in vitro. However, CSCs clearly have a complex pathogenesis, with a considerable crosstalk and redundancy in signaling pathways, and hence targeting single molecules or pathways may have a limited benefit for treatment. Many of the key signaling molecules are shared by both CSCs and normal stem cells, which add further challenges for designing molecularly targeted strategies specific to CSCs but sparing normal stem cells to avoid side effects. In addition to the direct control of CSCs, many other factors that are needed for the maintenance of CSCs, such as angiogenesis, vasculogenesis, invasion and migration, hypoxia, immune evasion, multiple drug resistance, and radioresistance, should be taken into consideration when designing therapeutic strategies for HCC.

Here we provide a brief review of molecular signaling in liver CSCs and present insights into new therapeutic strategies for targeting liver CSCs.

HCC and angiogenesis: possible targets and future directions

Hepatocellular carcinoma (HCC), the most common primary liver tumor, is notoriously resistant to systemic therapies, and often recurs even after aggressive local therapies. HCCs rely on the formation of new blood vessels for growth, and VEGF is critical in this process. A hallmark of new vessel formation in tumors is their structural and functional abnormality. This leads to an abnormal tumor microenvironment characterized by low oxygen tension. The liver is perfused by both arterial and venous blood and the resulting abnormal microenvironment selects for more-aggressive malignancies. Anti-VEGF therapy with sorafenib was the first systemic therapy to demonstrate improved survival in patients with advanced-stage HCC. This important development in the treatment of HCC raises hope as well as critical questions on the future development of targeted agents including other antiangiogenic agents, which hold promise to further increase survival in this aggressive disease.

The molecular pathogenesis and clinical implications of hepatocellular carcinoma

The prognosis of hepatocellular carcinoma (HCC) is affected by tumoral factors and liver functions; therefore it is often difficult to select the appropriate therapeutic methods for HCC. Recently, two global phase III trials showed that sorafenib, which is a tyrosine kinase inhibitor, improved the prognosis of patients with advanced HCC. As a new therapeutic strategy for HCC, sorafenib is expected to expand the indication for HCC in the future. However, it alone is insufficient for the molecular-targeted treatment of HCC because the signaling pathway exists not only in cancer cells but also in normal cells. Recently, cancer stem cells (CSCs) have attracted attention as a novel therapeutic target for HCC. There is now much evidence that stem cell properties such as self-renewal, unlimited proliferation, and differentiation are highly relevant to cancer recurrence and the drug resistance of HCC. In this review, we describe the molecular pathogenesis and the current state and future development of molecular- and CSC-therapeutic targeted agents for HCC, citing various reports.

Sulfatase 2 protects hepatocellular carcinoma cells against apoptosis induced by the PI3K inhibitor LY294002 and ERK and JNK kinase inhibitors

BACKGROUND

Sulfatase 2 (SULF2), an extracellular heparan sulphate 6-O-endosulphatase, has an oncogenic effect in hepatocellular carcinoma (HCC) that is partially mediated through glypican 3, which promotes heparin-binding growth factor signalling and HCC cell growth. SULF2 also increases phosphorylation of the anti-apoptotic Akt kinase substrate GSK3β and SULF2 expression is associated with a decreased apoptotic index in human HCCs.

METHODS

We investigated the functional and mechanistic effects of SULF2 on drug-induced apoptosis of HCC cells using immunohistochemistry, Western immunoblotting, gene transfection, real-time quantitative polymerase chain reaction, MTT and apoptosis assays and immunocytochemistry.

RESULTS

The increased expression of SULF2 in human HCCs was confirmed by immunohistochemistry and immunoblotting. Treatment with inhibitors of MEK, JNK and PI3 kinases decreased the viability of SULF2-negative Hep3B HCC cells and induced apoptotic caspase 3 and 7 activity, which was most strongly induced by the PI3K inhibitor LY294002. Forced expression of SULF2 in Hep3B cells significantly decreased activity of the apoptotic caspases 3 and 7 and induced resistance to LY294002-induced apoptosis. As expected, LY294002 inhibited activation of Akt kinase by PI3K. Conversely, knockdown of SULF2 using an shRNA construct targeting the SULF2 mRNA induced profound cell growth arrest and sensitized the endogenously SULF2-expressing HCC cell lines Huh7 and SNU182 to drug-induced apoptosis. The effects of knockdown of SULF2 on HCC cells were mediated by decreased Akt phosphorylation, downregulation of cyclin D1 and the anti-apoptotic molecule Bcl-2, and upregulation of the pro-apoptotic molecule BAD.

CONCLUSION

The prosurvival, anti-apoptotic effect of SULF2 in HCC is mediated through activation of the PI3K/Akt pathway.

The role of signaling pathways in the development and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly prevalent, treatment-resistant malignancy with a multifaceted molecular pathogenesis. Current evidence indicates that during hepatocarcinogenesis, two main pathogenic mechanisms prevail: (1) cirrhosis associated with hepatic regeneration after tissue damage caused by hepatitis infection, toxins (for example, alcohol or aflatoxin) or metabolic influences, and (2) mutations occurring in single or multiple oncogenes or tumor suppressor genes. Both mechanisms have been linked with alterations in several important cellular signaling pathways. These pathways are of interest from a therapeutic perspective, because targeting them may help to reverse, delay or prevent tumorigenesis. In this review, we explore some of the major pathways implicated in HCC. These include the RAF/MEK/ERK pathway, phosphatidylinositol-3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, WNT/beta-catenin pathway, insulin-like growth factor pathway, hepatocyte growth factor/c-MET pathway and growth factor-regulated angiogenic signaling. We focus on the role of these pathways in hepatocarcinogenesis, how they are altered, and the consequences of these abnormalities. In addition, we also review the latest preclinical and clinical data on the rationally designed targeted agents that are now being directed against these pathways, with early evidence of success.

Small molecule antagonists of Tcf4/beta-catenin complex inhibit the growth of HCC cells in vitro and in vivo

Hepatocellular carcinoma (HCC) is the 5th most common cancer worldwide. It is intrinsically resistant toward standard chemotherapy, making it imperative to develop novel selective chemotherapeutic agents. The Wnt/beta-catenin pathway plays critical roles in development and oncogenesis, and is dysregulated in HCC. Our study aims to evaluate the activity of 3 small molecule antagonists of the Tcf4/beta-catenin complex (PKF118-310, PKF115-584 and CGP049090) on HCC cell lines in vitro and in vivo. All 3 chemicals displayed dose-dependent cytotoxicity in vitro against all 3 HCC cell lines (HepG2, Hep40 and Huh7), but were at least 10 times less cytotoxic to normal hepatocytes (from 3 donors) by using ATP assay. In HepG2 and Huh7 cells, treatment with the antagonists decreased Tcf4/beta-catenin binding capability and transcriptional activity, associated with downregulation of the endogenous Tcf4/ beta-catenin target genes c-Myc, cyclin D1 and survivin. In HepG2 and Huh7 cells, treatment with the antagonists induced apoptosis and cell cycle arrest at the G1/S phase. All antagonists suppressed in vivo tumor growth in a HepG2 xenograft model, associated with apoptosis and reduced c-Myc, cyclin D1 and survivin expressions. Our results suggest that these 3 antagonists of the Tcf4/beta-catenin complex are potential chemotherapeutic agents which may offer a pathway specific option for the clinical management of HCC.

Identification of HTA as a novel-specific marker for human hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common malignancy in the world, especially in China. Early diagnosis of new and recurrent hepatocellular carcinoma, followed by timely treatment, will help decrease mortality. Currently biomarkers are not satisfactory. Better diagnostic methods are highly demanded.

METHODS

In this study, we have used in silico identification and RT-PCR test and discovered a hepatoma associated gene (HTA). Knockdown of endogenous HTA expression was performed by small interfering RNA in malignant hepatocyte HepG2. Then we tested the cell proliferative ability of these cells in vitro and in vivo.

RESULTS

HTA was expressed specifically in some kinds of tumors, but not detected in any normal tissues. It was expressed especially high in hepatocellular carcinoma. Knockdown of endogenous HTA expression in HepG2 by small interfering RNA attenuated HCC cell growth.

CONCLUSIONS

HCA is a very good marker for tumors, especially for HCC. It could play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.

PDGFRalpha: a new therapeutic target in the treatment of hepatocellular carcinoma?

BACKGROUND

Hepatocellular carcinoma (HCC) develops most often in a background of chronic inflammatory liver injury from viral infection or alcohol use. Most HCCs are diagnosed at a stage at which surgical resection is not feasible. Even in patients receiving surgery rates of recurrence and metastasis remain high. There are few effective HCC therapies and hence a need for novel, rational approaches to treatment. Platelet derived growth factor receptor-alpha (PDGFR-alpha) is involved in tumor angiogenesis and maintenance of the tumor microenvironment and has been implicated in development and metastasis of HCC.

OBJECTIVE

To examine PDGFR-alpha as a target for therapy of HCC and explore opportunities and strategies for PDGFR-alpha inhibition.

METHODS

A review of relevant literature.

RESULTS/CONCLUSIONS

Targeted inhibition of PDGFR-alpha is a rational strategy for prevention and therapy of HCC.

A quantitative proteomic approach for identification of potential biomarkers in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. In this study, our objective was to identify differentially regulated proteins in HCC through a quantitative proteomic approach using iTRAQ. More than 600 proteins were quantitated of which 59 proteins were overexpressed and 92 proteins were underexpressed in HCC as compared to adjacent normal tissue. Several differentially expressed proteins were not implicated previously in HCC. A subset of these proteins (six each from upregulated and downregulated groups) was further validated using immunoblotting and immunohistochemical labeling. Some of the overexpressed proteins with no previous description in the context of HCC include fibroleukin, interferon induced 56 kDa protein, milk fat globule-EGF factor 8, and myeloid-associated differentiation marker. Interestingly, all the enzymes of urea metabolic pathway were dramatically downregulated. Immunohistochemical labeling confirmed differential expression of fibroleukin, myeloid associated differentiation marker and ornithine carbamoyl transferase in majority of HCC samples analyzed. Our results demonstrate quantitative proteomics as a robust discovery tool for the identification of differentially regulated proteins in cancers.

Advances in experimental and translational research in the treatment of hepatocellular carcinoma

Hepatocellular cancer (HCC) is the fifth-leading cause of cancer and the third-leading cause of cancer related deaths world-wide. Current treatment options are limited, as HCC has been shown to be a highly resistant type of cancer to most current treatment modalities. Novel approaches are being explored in the fields of gene therapy, viral oncolytics, radioembolization, and several new biologic therapies. This article summarizes these recent clinical findings and discusses what role they will have in the future treatment of HCC.

Epigenetic instability is rare in fibrolamellar carcinomas but common in viral-associated hepatocellular carcinomas

Fibrolamellar carcinomas have a unique predilection for younger individuals and arise in livers without recognizable liver disease. In contrast to typical hepatocellular carcinomas, fibrolamellar carcinomas show few chromosomal changes and lack mutation in key genes such as TP53 and CTNNB1. Epigenetic instability, manifesting as methylation of important tumor suppressor gene promoters, has not been investigated in fibrolamellar carcinomas. Thus, the methylation status of 11 tumor suppressor gene promoters was investigated using methylation-specific PCR: RASSF1, CDH1, CDKN2B, HPP1, CDKN2A, GSTP1, P16, RARA, FLJ13081, SOCS1, and TP53. Nine fibrolamellar carcinomas were studied including primary tumors (N=5) and metastatic deposits (N=4) along with control groups of typical hepatocellular carcinoma arising in livers with (N=21) and without cirrhosis (N=10). In fibrolamellar carcinomas, RASSF1A and CDH1 (e-cadherin) were the most commonly methylated genes with 80-100% of tumors methylated. However, overall fibrolamellar carcinomas showed low levels of methylation with no differences between fibrolamellar carcinomas and their paired normal livers. However, fibrolamellar carcinomas showed significantly less methylation than hepatocellular carcinomas that arose in the background of viral cirrhosis. Overall, methylation was most strongly linked to viral cirrhosis. In conclusion, fibrolamellar carcinoma shows low levels of methylation. In contrast, higher levels of promoter methylation are associated with hepatocellular carcinomas that arise in the setting of viral induced cirrhosis.

Sorafenib: in hepatocellular carcinoma

Sorafenib is an orally active multikinase inhibitor with anti-tumour activity. It was recently approved in the US and the EU for the treatment of patients with hepatocellular carcinoma. Oral sorafenib 400 mg twice daily significantly improved survival in patients with advanced hepatocellular carcinoma in the randomized, double-blind, multicentre, phase III SHARP trial (n = 602); the median duration of survival was 10.7 months with sorafenib and 7.9 months with placebo. In addition, the median time to progression was significantly longer in patients receiving sorafenib than in those receiving placebo (5.5 vs 2.8 months). Combination therapy with oral sorafenib 400 mg twice daily and intravenous doxorubicin has potential in the treatment of patients with advanced hepatocellular carcinoma, according to the results of a randomized, double-blind, phase II study (n = 96). Although the addition of sorafenib to doxorubicin did not significantly delay the time to progression, the median durations of overall survival and progression-free survival were significantly longer with sorafenib plus doxorubicin than with doxorubicin alone. Monotherapy with oral sorafenib 400 mg twice daily was generally well tolerated in patients with advanced hepatocellular carcinoma, with a manageable adverse event profile.

Sulfatase 2 up-regulates glypican 3, promotes fibroblast growth factor signaling, and decreases survival in hepatocellular carcinoma

It has been shown that the heparin-degrading endosulfatase, sulfatase 1 (SULF1), functions as a liver tumor suppressor, but the role of the related sulfatase, sulfatase 2 (SULF2), in liver carcinogenesis remains to be elucidated. We investigated the effect of SULF2 on liver tumorigenesis. Expression of SULF2 was increased in 79 (57%) of 139 hepatocellular carcinomas (HCCs) and 8 (73%) of 11 HCC cell lines. Forced expression of SULF2 increased HCC cell growth and migration, whereas knockdown of SULF2 using short hairpin RNA targeting SULF2 abrogated HCC cell proliferation and migration in vitro. Because SULF1 and SULF2 desulfate heparan sulfate proteoglycans (HSPGs) and the HSPG glypican 3 (GPC3) is up-regulated in HCC, we investigated the effects of SULF2 on GPC3 expression and the association of SULF2 with GPC3. SULF2-mediated cell growth was associated with increased binding of fibroblast growth factor 2 (FGF2), phosphorylation of extracellular signal-regulated kinase and AKT, and expression of GPC3. Knockdown of GPC3 attenuated FGF2 binding in SULF2-expressing HCC cells. The effects of SULF2 on up-regulation of GPC3 and tumor growth were confirmed in nude mouse xenografts. Moreover, HCC patients with increased SULF2 expression in resected HCC tissues had a worse prognosis and a higher rate of recurrence after surgery.

CONCLUSION

In contrast to the tumor suppressor effect of SULF1, SULF2 has an oncogenic effect in HCC mediated in part through up-regulation of FGF signaling and GPC3 expression.

Genetic diversity of hepatocellular carcinomas and its potential impact on targeted therapies

Hepatocellular carcinoma (HCC) is one of the most frequent solid tumors worldwide and represents the third cause of mortality among deaths from cancer. It has been extensively studied in terms of genetic alteration in the last 10 years and our knowledge has dramatically increased in this field, leading to the definition of different altered pathways in hepatocarcinogenesis. Recently, a comprehensive study of genetic and transcriptomic alterations in a large series of HCC tumors enabled the identification of a six-group molecular-based classification of HCC, defined by a simple 16-gene signature. This classification is closely related to specific alteration of WNT and AKT oncogenic pathways. Together with the analysis of defined oncogenic proteins, such global classifications could be useful in the prediction of future-targeted therapy efficiency.