Effect of phosphorylation of MAPK and Stat3 and expression of c-fos and c-jun proteins on hepatocarcinogenesis and their clinical significance

Understanding Gene Involvement in Hepatocellular Carcinoma: Implications for Gene Therapy and Personalized Medicine

Hepatocellular carcinoma (HCC) is the dominant type of liver cancers and is one of the deadliest health threats globally. The conventional therapeutic options for HCC are hampered by low efficiency and intolerable side effects. Gene therapy, however, now offers hope for the treatment of many disorders previously considered incurable, and gene therapy is beginning to address many of the shortcomings of conventional therapies. Herein, we summarize the involvement of genes in the pathogenesis and prognosis of HCC, with a special focus on dysregulated signaling pathways, genes involved in immune evasion, and non-coding RNAs as novel two-edged players, which collectively offer potential targets for the gene therapy of HCC. Herein, the opportunities and challenges of HCC gene therapy are discussed. These include innovative therapies such as genome editing and cell therapies. Moreover, advanced gene delivery technologies that recruit nanomedicines for use in gene therapy for HCC are highlighted. Finally, suggestions are offered for improved clinical translation and future directions in this area of endeavor.

Ozonated Water Inhibits Hepatocellular Carcinoma Invasion and Metastasis by Regulating the HMGB1/NF-κB/STAT3 Signaling Pathway

Background

Hepatocellular carcinoma (HCC) is one of the deadliest cancers worldwide. High-mobility group box 1 (HMGB1), a highly conserved chromosome protein, is considered as a potential therapeutic target and novel biomarker because of its regulation in the proliferation and metastasis of HCC. Ozone has been shown to be beneficial in the treatment of cancer. The objective of this study was to explore the effects and molecular mechanism of ozonated water on the proliferation, migration, and invasion of BEL7402 HCC cells.

Materials and Methods

We assessed cell proliferation using a CCK-8 assay kit and flow cytometry; we performed wound healing and transwell assays to evaluate the effects of ozonated water treatment on cell invasion and migration. We determined reactive oxygen species (ROS) values by flow cytometry and used ELISAs to detect cytokines HMGB1, IL-6, and TNF-α. In addition, we assessed mRNA and protein cytokine expressions using RT-qPCR and Western blot.

Results

Ozonated water decreased the viability of the HCC cells; the IC50 of ozonated water at 24 h was approximately 1.5 μg/mL. Compared with control groups, ozone treated cells revealed reduced mobility on wound healing assays and decreased invasion in transwell assays. HMGB1, IL-6, and TNF-α cytokines were found at lower levels in ozone treated cells than in control cells. Ozonated water-induced ROS accumulation. Likewise, the expressions of phosphorylated nuclear factor Kappa B (NF-κB), p65, NF-κB, P-STAT3, IL-6, JAK2, Slug, Twist, vimentin, MMP-2, MMP-9, and HMGB1 were decreased in the treated cells.

Conclusion

Our findings suggest that ozonated water inhibits the proliferation, invasion, and metastasis of HCC cells via regulation of the HMGB1/NF-κB/STAT3 signaling pathway.

Expression of p-STAT3 and c-Myc correlates with P2-HNF4α expression in nonalcoholic fatty liver disease (NAFLD)

We studied the expression of two hepatocyte nuclear factor 4 alpha (HNF4α) isoforms, p-STAT3. and c-Myc in 49 consecutive liver biopsies with nonalcoholic fatty liver disease (NAFLD) using immunohistochemistry. All 49 biopsies (100%) were positive for nuclear expression of P1-HNF4α. Twenty-eight (57%) cases were positive for P2-HNF4α, 6 (12%) were positive for p-STAT3 and 5 (10%) were positive for c-Myc. All 6 (100%) p-STAT3-positive cases were also positive for P2-HNF4α (p = 0.03). p-STAT3-positive cases were more likely to be positive for c-Myc (67% vs. 2%, p = 0.0003). Four cases were positive for P2-HNF4α, p-STAT3 and c-Myc. p-STAT3 expression was associated with hypertension (p = 0.037). All c-Myc positive biopsies were from patients with obesity, diabetes and hypertension. Only c-Myc expression was associated with advanced fibrosis; three (60%) of the c-Myc positive cases were associated with advanced fibrosis in contrast to 7 (10%) of the 44 c-Myc negative cases (p = 0.011). Based on these results, we hypothesize with the following sequence of events with progression of NAFLD: P2-HNF4α expression is followed by expression of p-STAT3 which in turn is followed by the expression of c-Myc. Additional larger studies are needed to confirm these findings.

Dark and bright side of targeting fibroblast growth factor receptor 4 in the liver

Fibroblast growth factor (FGF) receptor 4 (FGFR4) and its cognate ligand, FGF19, are implicated in a range of cellular processes, including differentiation, metabolism and proliferation. Indeed, their aberrant activation has been associated with the development of hepatic tumours. Despite great advances in early diagnosis and the development of new therapies, liver cancer is still associated with a high mortality rate, owing primarily to high molecular heterogeneity and unclear molecular targeting. The development of FGFR4 inhibitors is a promising tool in patients with concomitant supraphysiological levels of FGF19 and several clinical trials are testing these treatments for patients with advanced hepatocellular carcinoma (HCC). Conversely, using FGF19 analogues to activate FGFR4-KLOTHO β represents a novel therapeutic strategy in patients presenting with cholestatic liver disorders and non-alcoholic steatohepatitis, which could potentially prevent the development of metabolic HCC. Herein, we provide an overview of the currently available therapeutic options for targeting FGFR4 in HCC and other liver diseases, highlighting the need to carefully stratify patients and personalise therapeutic strategies.

A novel therapeutic strategy for hepatocellular carcinoma: Immunomodulatory mechanisms of selenium and/or selenoproteins on a shift towards anti-cancer

Selenium (Se) is an essential trace chemical element that is widely distributed worldwide. Se exerts its immunomodulatory and nutritional activities in the human body in the form of selenoproteins. Se has increasingly appeared as a potential trace element associated with many human diseases, including hepatocellular carcinoma (HCC). Recently, increasing evidence has suggested that Se and selenoproteins exert their immunomodulatory effects on HCC by regulating the molecules of oxidative stress, inflammation, immune response, cell proliferation and growth, angiogenesis, signaling pathways, apoptosis, and other processes in vitro cell studies and in vivo animal studies. Se concentrations are generally low in tissues of patients with HCC, such as blood, serum, scalp hair, and toenail. However, Se concentrations were higher in HCC patient tissues after Se supplementation than before supplementation. This review summarizes the significant relationship between Se and HCC, and details the role of Se as a novel immunomodulatory or immunotherapeutic approach against HCC.

Ras Mitogen-activated Protein Kinase Signaling and Kinase Suppressor of Ras as Therapeutic Targets for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a high incidence cancer and a major health concern worldwide. Among the many molecular signaling pathways that are dysregulated in HCC, the Ras mitogen-activated protein kinase (Ras/Raf/MAPK) signaling pathway has gained renewed attention from basic and clinical researchers. Mutations in Ras and Raf genes which are known to activate the Ras/Raf/MAPK signaling pathway have been infrequently detected in human HCC; however, the Ras/Raf/MAPK signaling pathway is activated in more than 50% of HCC cases, suggesting an alternative mechanism for the activation of the signaling pathway. Kinase suppressor of Ras acts as a molecular scaffold for facilitating the assembly of Ras/Raf/MAPK signaling pathway components and has been implicated in the regulation of this signaling pathway. In this review, we provide important insights into the cellular and molecular mechanisms involved in the activation of the Ras/Raf/MAPK signaling pathway and discuss potential therapeutic strategies for HCC.

Identification of the possible therapeutic targets in the insulin-like growth factor 1 receptor pathway in a cohort of Egyptian hepatocellular carcinoma complicating chronic hepatitis C type 4

Background:

Molecular targeted drugs are the first line of treatment of advanced hepatocellular carcinoma (HCC) due to its chemo- and radioresistant nature. HCC has several well-documented etiologic factors that drive hepatocarcinogenesis through different molecular pathways. Currently, hepatitis C virus (HCV) is a leading cause of HCC. Therefore, we included a unified cohort of HCV genotype 4-related HCCs to study the expression levels of genes involved in the insulin-like growth factor 1 receptor (IGF1R) pathway, which is known to be involved in all aspects of cancer growth and progression.

Aim:

Determine the gene expression patterns of IGF1R pathway genes in a cohort of Egyptian HCV-related HCCs. Correlate them with different patient/tumor characteristics. Determine the activity status of involved pathways.

Methods:

Total ribonucleic acid (RNA) was extracted from 32 formalin-fixed paraffin-embedded tissues of human HCV-related HCCs and 6 healthy liver donors as controls. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) using RT² Profiler PCR Array for Human Insulin Signaling Pathway was done to determine significantly up- and downregulated genes with identification of most frequently coregulated genes, followed by correlation of gene expression with different patient/tumor characteristics. Finally, canonical pathway analysis was performed using the Ingenuity Pathway Analysis software.

Results:

Six genes – AEBP1, AKT2, C-FOS, PIK3R1, PRKCI, SHC1 – were significantly overexpressed. Thirteen genes – ADRB3, CEBPA, DUSP14, ERCC1, FRS3, IGF2, INS, IRS1, JUN, MTOR, PIK3R2, PPP1CA, RPS6KA1 – were significantly underexpressed. Several differentially expressed genes were related to different tumor/patient characteristics. Nitric oxide and reactive oxygen species production pathway was significantly activated in the present cohort, while the growth hormone signaling pathway was inactive.

Conclusions:

The gene expression patterns identified in this study may serve as possible therapeutic targets in HCV-related HCCs. The most frequently coregulated genes may serve to guide combined molecular targeted therapies. The IGF1R pathway showed evidence of inactivity in the present cohort of HCV-related HCCs, so targeting this pathway in therapy may not be effective.

Molecular Signaling Pathways and Therapeutic Targets in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a complex biological process and is often diagnosed at advanced stages with no effective treatment options. With advances in tumor biology and molecular genetic profiling, several different signaling pathways and molecular mechanisms have been identified as responsible for initiating and promoting HCC. Targeting these critical pathways, which include the receptor tyrosine kinase pathways, the Ras mitogen-activated protein kinase (Ras/Raf/MAPK), the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR), the Wnt/β-catenin signaling pathway, the ubiquitin/proteasome degradation and the hedgehog signaling pathway has led to the identification of novel therapeutics for HCC treatment. In this review, we elaborated on our current understanding of the signaling pathways involved in the development and initiation of HCC and anticipate the potential targets for therapeutic drug development.

Metabolomics for Biomarker Discovery in Fermented Black Garlic and Potential Bioprotective Responses against Cardiovascular Diseases

Fermented black garlic has multiple beneficial biological activities, including cardiovascular protection, anticancer, hepatoprotective, and antibacterial properties. In this study, metabolic differences in the properties of black and fresh garlic were investigated via liquid chromatography quadrupole/time-of-flight-based metabolomics, leading to the identification of characteristic components. Fermented black garlic samples and their Amadori products (AC) promoted angiogenesis, prevented thrombus formation by rescuing chemical-induced vascular lesions in zebrafish, and inhibited H₂O₂-induced injury of endothelial cells, thus reducing the risk of cardiovascular disease. AC suppressed activation of the mitogen-activated protein kinase pathway through inhibition of p38 and ERK1/2 phosphorylation, in turn, increasing the availability of c-Fos/c-Jun or c-Jun/c-Jun complexes for apoptotic resistance. Clarification of the associated signaling pathways should therefore provide a solid foundation for optimization of black garlic-based therapies.

STAT3: An Emerging Therapeutic Target for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a major global health problem and its treatment options have been limited. Signal transducer and activator of transcription 3 (STAT3) is a transcription factor important for various cellular processes. Overexpression and constitutive activation of STAT3 have been frequently found in HCC and associated with poor prognosis. Ample evidence has shown that STAT3 plays pivotal roles in the initiation, progression, metastasis and immune suppression of HCC. Thus, STAT3 has attracted attention as a novel therapeutic target in HCC. Clinical trials have investigated STAT3-targeted therapeutics either as monotherapy or in combination with chemotherapeutic agents, immune checkpoint inhibitors and alternative targeted drugs. Some of these studies have yielded encouraging results. Particularly, napabucasin—a cancer stemness inhibitor targeting STAT3-driven gene transcription—has stood out with its promising clinical efficacy and safety profile. Nonetheless, clinical investigations of STAT3-targeted therapies in HCC are limited and more efforts are strongly urged to evaluate their clinical performance in HCC. Here, we provide a comprehensive review of the roles of STAT3 in HCC and follow by comprehensive analysis of STAT3 targeted strategies.

Capsaicin: Effects on the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent cancers, and to date, there have been very few drugs available that can improve survival, the most well-known being sorafenib. The pathogenesis of HCC is complex, involving multiple processes including abnormal cell and tissue regeneration, angiogenesis, genomic instability, cellular proliferation, and signaling pathway alterations. Capsaicin is a substance that holds increasingly high interest and is studied as a therapeutic option in a wide array of diseases. Several studies have investigated capsaicin roles in various stages of HCC oncogenesis. This paper aims to thoroughly detail the available information on the individual effects of capsaicin on the cellular mechanisms and pathways involved in HCC development, as well as investigate their possible cooperation and interferences. The synergistic antitumor effects of capsaicin and sorafenib are also addressed.

Potential diagnostic and prognostic marker dimethylglycine dehydrogenase (DMGDH) suppresses hepatocellular carcinoma metastasis in vitro and in vivo

Key metabolic enzymes regulatethe fluxes of small compounds to provide the basal substrates for cellular architecture and energy. Some of them are reported to be important carcinogenesis- and metastasis-related genes. In our work, we performed RNA-seq for50 pairs of normal-tumor of hepatocellular carcinoma (HCC) samples and found that the expression of dimethylglycine dehydrogenase (DMGDH) is decreased in HCC. The analysis of protein levels with Western blotting and immunohistochemistry also conformed our findings. It is proven to be a valuable biomarker for both diagnosis and prognosis in three independent datasets. Furthermore, we revealed that DMGDH suppresses migration, invasion and metastasis both in vitro and in vivo. By utilizing gene expression microarray for DMGDH, we identified several possible pathways altered in a DMGDH over-expressing cell line. Among these pathways, we noted that the phosphorylation of Akt-308/473 was significantly suppressed when DMGDH was over-expressed. In summary, our work reveals that DMGDH is a potential valuable biomarker for both diagnosis and prognosisfor HCC, and DMGDH gene expression suppresses metastasis through the Akt signaling pathway.

Morin enhances hepatic Nrf2 expression in a liver fibrosis rat model

AIM

To investigate whether morin can reduce hepatic fibrosis by activating the NF-E2-related factor 2 (Nrf2) signaling pathway.

METHODS

Twenty male Sprague-Dawley rats were randomly divided into four groups: control group, morin group, carbon tetrachloride (CCl₄) group, and morin + CCl₄ group. Rats in both the CCl₄ and morin + CCl₄ groups were injected intraperitoneally with CCl₄ at a dose of 2 mL/kg twice a week. Rats in both the morin and morin + CCl₄ groups were treated orally with morin at a dose of 50 mg/kg twice a week. Control rats were treated with vehicle only twice a week. At the end-point of the 8 wk of the experimental period, serum AST, ALT, and ALP were measured, and the liver specimens were obtained for pathological assessment. Real-time PCR and Western blot methods were used to analyze the expression of α-smooth muscle actin (α-SMA), collagen I, collagen III, Nrf2, heme oxygenase (HO-1), and quinone oxidoreductase 1 (NQO1) using frozen liver specimens.

RESULTS

Morin-treated rats in the morin + CCl₄ group had less hyperplasia of fiber tissue, minimal inflammatory cells, and less body weight loss with favorable liver enzyme measurements compared to rats treated with CCl₄ only. Additionally, morin-treated rats had significantly lower mRNA and protein expression of α-SMA, collagen I, and collagen III, but significantly higher mRNA and protein expression of Nrf2, HO-1, and NQO1 compared to rats treated with CCl₄ only (P < 0.05).

CONCLUSION

Morin could play a protective role by inducing the expression of Nrf2 and its downstream antioxidant factors (HO-1 and NQO1) and reducing the expression of α-SMA, collagen I, and collagen III in CCl₄-induced liver fibrosis rats.

RB/PLK1-dependent induced pathway by SLAMF3 expression inhibits mitosis and control hepatocarcinoma cell proliferation

Polo-like kinase PLK1 is a cell cycle protein that plays multiple roles in promoting cell cycle progression. Among the many roles, the most prominent role of PLK1 is to regulate the mitotic spindle formation checkpoint at the M-phase. Recently we reported the expression of SLAMF3 in Hepatocytes and show that it is down regulated in tumor cells of hepatocellular carcinoma (HCC). We also show that the forced high expression level of SLAMF3 in HCC cells controls proliferation by inhibiting the MAPK ERK/JNK and the mTOR pathways. In the present study, we provide evidence that the inhibitory effect of SLAMF3 on HCC proliferation occurs through Retinoblastoma (RB) factor and PLK1-dependent pathway. In addition to the inhibition of MAPK ERK/JNK and the mTOR pathways, expression of SLAMF3 in HCC retains RB factor in its hypophosphorylated active form, which in turn inactivates E2F transcription factor, thereby repressing the expression and activation of PLK1. A clear inverse correlation was also observed between SLAMF3 and PLK expression in patients with HCC. In conclusion, the results presented here suggest that the tumor suppressor potential of SLAMF3 occurs through activation of RB that represses PLK1. We propose that the induction of a high expression level of SLAMF3 in cancerous cells could control cellular mitosis and block tumor progression.

Sorafenib enriches epithelial cell adhesion molecule-positive tumor initiating cells and exacerbates a subtype of hepatocellular carcinoma through TSC2-AKT cascade

Sorafenib is a specific adenosine triphosphate-competitive RAF inhibitor used as a first-line treatment of advanced hepatocellular carcinoma (HCC). However, the responses are variable, reflecting heterogeneity of the disease, while the resistance mechanism remains poorly understood. Here, we report that sorafenib treatment can exacerbate disease progression in both patient-derived xenografts and cell line-derived xenografts and that the therapeutic effect of the drug inversely covaries to the ratio of epithelial cell adhesion molecule-positive cells, which may be tumor initiating cells in HCC. The TSC2-AKT cascade mediates this sorafenib resistance. In response to sorafenib treatment, formation of the TSC1/2 complex is enhanced, causing increased phosphorylation of AKT, which contributes to up-regulation of "stemness"-related genes in epithelial cell adhesion molecule-positive cells and enhancement of tumorigenicity. The expression of TSC2 negatively correlated with prognosis in clinical sorafenib therapy. Furthermore, all-trans retinoic acid decreased AKT activity, reduced the epithelial cell adhesion molecule-positive cell population enriched by sorafenib, and potentiated the therapeutic effect of sorafenib in the patient-derived xenograft model.

CONCLUSION

Our findings suggest that a subtype of HCC is not suitable for sorafenib therapy; this resistance to sorafenib can be predicted by the status of TSC2, and agents inducing differentiation of tumor initiating cells (e.g., all-trans retinoic acid) should improve the prognosis of this subtype of HCC.

The Complex Relationship between Liver Cancer and the Cell Cycle: A Story of Multiple Regulations

The liver acts as a hub for metabolic reactions to keep a homeostatic balance during development and growth. The process of liver cancer development, although poorly understood, is related to different etiologic factors like toxins, alcohol, or viral infection. At the molecular level, liver cancer is characterized by a disruption of cell cycle regulation through many molecular mechanisms. In this review, we focus on the mechanisms underlying the lack of regulation of the cell cycle during liver cancer, focusing mainly on hepatocellular carcinoma (HCC). We also provide a brief summary of novel therapies connected to cell cycle regulation.

Targeting the STAT3 signaling pathway in cancer: role of synthetic and natural inhibitors

Signal transducers and activators of transcription (STATs) comprise a family of cytoplasmic transcription factors that mediate intracellular signaling that is usually generated at cell surface receptors and thereby transmit it to the nucleus. Numerous studies have demonstrated constitutive activation of STAT3 in a wide variety of human tumors, including hematological malignancies (leukemias, lymphomas, and multiple myeloma) as well as diverse solid tumors (such as head and neck, breast, lung, gastric, hepatocellular, colorectal and prostate cancers). There is strong evidence to suggest that aberrant STAT3 signaling promotes initiation and progression of human cancers by either inhibiting apoptosis or inducing cell proliferation, angiogenesis, invasion, and metastasis. Suppression of STAT3 activation results in the induction of apoptosis in tumor cells, and accordingly its pharmacological modulation by tyrosine kinase inhibitors, antisense oligonucleotides, decoy nucleotides, dominant negative proteins, RNA interference and chemopreventive agents have been employed to suppress the proliferation of various human cancer cells in culture and tumorigenicity in vivo. However, the identification and development of novel drugs that can target deregulated STAT3 activation effectively remains an important scientific and clinical challenge. This review presents the evidence for critical roles of STAT3 in oncogenesis and discusses the potential for development of novel cancer therapies based on mechanistic understanding of STAT3 signaling cascade.

Identification of SLAMF3 (CD229) as an inhibitor of hepatocellular carcinoma cell proliferation and tumour progression

Although hepatocellular carcinoma (HCC) is one of the most common malignancies and constitutes the third leading cause of cancer-related deaths, the underlying molecular mechanisms are not fully understood. In the present study, we demonstrate for the first time that hepatocytes express signalling lymphocytic activation molecule family member 3 (SLAMF3/CD229) but not other SLAMF members. We provide evidence to show that SLAMF3 is involved in the control of hepatocyte proliferation and in hepatocellular carcinogenesis. SLAMF3 expression is significantly lower in primary human HCC samples and HCC cell lines than in human healthy primary hepatocytes. In HCC cell lines, the restoration of high levels of SLAMF3 expression inhibited cell proliferation and migration and enhanced apoptosis. Furthermore, SLAMF3 expression was associated with inhibition of HCC xenograft progression in the nude mouse model. The restoration of SLAMF3 expression levels also decreased the phosphorylation of MAPK ERK1/2, JNK and mTOR. In samples from resected HCC patients, SLAMF3 expression levels were significantly lower in tumorous tissues than in peritumoral tissues. Our results identify SLAMF3 as a specific marker of normal hepatocytes and provide evidence for its potential role in the control of proliferation of HCC cells.

Cardiac hormones target nuclear oncogenes c-Fos and c-Jun in carcinoma cells

BACKGROUND

c-Fos is a cellular proto-oncogene which dimerizes with c-Jun proto-oncogene to form AP-1 transcription factor, which upregulates transcription of genes involved in proliferation and cancer formation. Four cardiac hormones, that is, long-acting natriuretic peptide (LANP), vessel dilator, kaliuretic peptide (KP) and atrial natriuretic peptide (ANP) with anticancer effects in vivo are potent inhibitors of the Ras-MEK 1/2-ERK 1/2 kinase cascade and signal transducer and activator of transcription-3 (STAT-3) that activate c-Fos and c-Jun. These four cardiac hormones were investigated for their effects on proto-oncogenes c-Fos and c-Jun within the nucleus of cancer cells.

MATERIALS AND METHODS

Four cardiac hormones were evaluated for their ability to decrease proto-oncogenes c-Fos and c-Jun, measured by ELISA in extracted nuclei of three human cancer cell lines.

RESULTS

Vessel dilator, LANP, KP and ANP over a concentration range of 100 pM-10 μM, maximally decreased c-Fos by 61%, 60%, 61% and 59% in human hepatocellular cancer cells, by 82%, 74%, 78% and 74% in small-cell lung cancer cells, and by 82%, 73%, 78% and 74% in human renal adenocarcinoma cells. c-Jun was maximally reduced by vessel dilator, LANP, KP and ANP by 43%, 31%, 61% and 35% in hepatocellular cancer cells, by 65%, 49%, 59% and 40% in small-cell lung cancer cells, and by 47%, 43%, 57% and 49% in renal cancer cells.

CONCLUSION

Four cardiac hormones are potent inhibitors of c-Fos and c-Jun proto-oncogenes within the nucleus of cancer cells.

Signal transduction disturbance related to hepatocarcinogenesis in mouse by prolonged exposure to Nanjing drinking water

Toxicogenomic approaches were used to investigate the potential hepatocarcinogenic effects on mice by oral exposure to Nanjing drinking water (NJDW). Changes in the hepatic transcriptome of 3 weeks male mice (Mus musculus) were monitored and dissected after oral exposure to NJDW for 90 days. No preneoplastic and neoplastic lesions were observed in the hepatic tissue by the end of NJDW exposure. However, total of 746 genes were changed transcriptionally. Thirty-one percent of differentially expressed genes (DEGs) were associated with the functional categories of cell cycle regulation, adhesion, growth, apoptosis, and signal transduction, which are closely implicated in tumorigenesis and progression. Interrogation of Kyoto Encyclopedia of Genes and Genomes revealed that 43 DEGs were mapped to several crucial signaling pathways implicated in the pathogenesis of hepatocellular carcinoma (HCC). In signal transduction network constructed via Genes2Networks software, Egfr, Akt1, Atf2, Ctnnb1, Hras, Mapk1, Smad2, and Ccnd1 were hubs. Direct gene-disease relationships obtained from Comparative Toxicogenomics Database and scientific literatures revealed that the hubs have direct mechanism or biomarker relationships with hepatocellular preneoplastic lesions or hepatocarcinogenesis. Therefore, prolonged intake of NJDW without employing any indoor water treatment strategy might predispose mouse to HCC. Furthermore, Egfr, Akt1, Ctnnb1, Hras, Mapk1, Smad2, and Ccnd1 were identified as promising biomarkers of the potential combined hepatocarcinogenicity.

Potential role of signal transducer and activator of transcription (STAT)3 signaling pathway in inflammation, survival, proliferation and invasion of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies, and is also the fourth most common cancer worldwide with around 700,000 new cases each year. Currently, first line chemotherapeutic drugs used for HCC include fluorouracil, cisplatin, doxorubicin, paclitaxel and mitomycin, but most of these are non-selective cytotoxic molecules with significant side effects. Sorafenib is the only approved targeted therapy by the U.S. Food and Drug Administration for HCC treatment, but patients suffer from various kinds of adverse effects, including hypertension. The signal-transducer-and-activator-of-transcription 3 (STAT3) protein, one of the members of STATs transcription factor family, has been implicated in signal transduction by different cytokines, growth factors and oncogenes. In normal cells, STAT3 activation is tightly controlled to prevent dysregulated gene transcription, whereas constitutively activated STAT3 plays an important role in tumorigenesis through the upregulation of genes involved in anti-apoptosis, proliferation and angiogenesis. Thus, pharmacologically safe and effective agents that can block STAT3 activation have the potential both for the prevention and treatment of HCC. In the present review, we discuss the possible role of STAT3 signaling cascade and its interacting partners in the initiation of HCC and also analyze the role of various STAT3 regulated genes in HCC progression, inflammation, survival, invasion and angiogenesis.

Retinoic acid and cAMP inhibit rat hepatocellular carcinoma cell proliferation and enhance cell differentiation

Hepatocellular carcinoma (HCC) is the third highest cause of cancer death worldwide. In general, the disease is diagnosed at an advanced stage when potentially curative therapies are no longer feasible. For this reason, it is very important to develop new therapeutic approaches. Retinoic acid (RA) is a natural derivative of vitamin A that regulates important biological processes including cell proliferation and differentiation. In vitro studies have shown that RA is effective in inhibiting growth of HCC cells; however, responsiveness to treatment varies among different HCC cell lines. The objective of the present study was to determine if the combined use of RA (0.1 µM) and cAMP (1 mM), an important second messenger, improves the responsiveness of HCC cells to RA treatment. We evaluated the proliferative behavior of an HCC cell line (HTC) and the expression profile of genes related to cancer signaling pathway (ERK and GSK-3β) and liver differentiation (E-cadherin, connexin 26 (Cx26), and Cx32). RA and cAMP were effective in inhibiting the proliferation of HTC cells independently of combined use. However, when a mixture of RA and cAMP was used, the signals concerning the degree of cell differentiation were increased. As demonstrated by Western blot, the treatment increased E-cadherin, Cx26, Cx32 and Ser9-GSK-3β (inactive form) expression while the expression of Cx43, Tyr216-GSK-3β (active form) and phosphorylated ERK decreased. Furthermore, telomerase activity was inhibited along treatment. Taken together, the results showed that the combined use of RA and cAMP is more effective in inducing differentiation of HTC cells.

Primate-specific microRNA-637 inhibits tumorigenesis in hepatocellular carcinoma by disrupting signal transducer and activator of transcription 3 signaling

MiR-637 (microRNA-637) is a primate-specific miRNA belonging to the small noncoding RNA family, which represses gene regulation at the post-transcriptional expression level. Although it was discovered approximately 5 years ago, its biomedical significance and regulatory mechanism remain obscure. Our preliminary data showed that miR-637 was significantly suppressed in four HCC cell lines and, also, in most of the hepatocellular carcinoma (HCC) specimens, thereby suggesting that miR-637 would be a tumor suppressor in HCC. Simultaneously, the enforced overexpression of miR-637 dramatically inhibited cell growth and induced the apoptosis of HCC cells. The transcription factor, signal transducer and activator of transcription 3 (Stat3), is constitutively activated in multiple tumors, and aberrant Stat3 activation is linked to the promotion of growth and desensitization of apoptosis. Our study showed that Stat3 tyrosine 705 phosphorylation and several Stat3-regulated antiapoptotic genes were down-regulated in miR-637 mimics-transfected and Lv-miR637-infected HCC cells. In addition, miR-637 overexpression negatively regulated Stat3 phosphorylation by suppressing autocrine leukemia inhibitory factor (LIF) expression and exogenous LIF-triggered Stat3 activation and rescued cell growth in these cells. A nude mice model also demonstrated the above-described results, which were obtained from the cell model. Furthermore, we found that LIF was highly expressed in a large proportion of HCC specimens, and its expression was inversely associated with miR-637 expression.

CONCLUSION

Our data indicate that miR-637 acted as a tumor suppressor in HCC, and the suppressive effect was mediated, at least in part, by the disruption of Stat3 activation.

Global gene profiling of spontaneous hepatocellular carcinoma in B6C3F1 mice: similarities in the molecular landscape with human liver cancer

Hepatocellular carcinoma (HCC) is an important cause of morbidity and mortality worldwide. Although the risk factors of human HCC are well known, the molecular pathogenesis of this disease is complex, and in general, treatment options remain poor. The use of rodent models to study human cancer has been extensively pursued, both through genetically engineered rodents and rodent models used in carcinogenicity and toxicology studies. In particular, the B6C3F1 mouse used in the National Toxicology Program (NTP) two-year bioassay has been used to evaluate the carcinogenic effects of environmental and occupational chemicals, and other compounds. The high incidence of spontaneous HCC in the B6C3F1 mouse has challenged its use as a model for chemically induced HCC in terms of relevance to the human disease. Using global gene expression profiling, we identify the dysregulation of several mediators similarly altered in human HCC, including re-expression of fetal oncogenes, upregulation of protooncogenes, downregulation of tumor suppressor genes, and abnormal expression of cell cycle mediators, growth factors, apoptosis regulators, and angiogenesis and extracellular matrix remodeling factors. Although major differences in etiology and pathogenesis remain between human and mouse HCC, there are important similarities in global gene expression and molecular pathways dysregulated in mouse and human HCC. These data provide further support for the use of this model in hazard identification of compounds with potential human carcinogenicity risk, and may help in better understanding the mechanisms of tumorigenesis resulting from chemical exposure in the NTP two-year carcinogenicity bioassay.

Emerging strategies in the treatment of advanced hepatocellular carcinoma: the role of targeted therapies

Hepatocellular cancer (HCC) is the fifth most common cause of cancer worldwide and its incidence is increasing as a result of the dissemination of hepatitis B and C virus infection. Surgical resection and liver transplantation are considered the only cures for HCC, but benefit approximately 10-15% of patients. In addition, radiofrequency ablation may is potentially curative for patients' with small HCC. Some patients with unresectable disease confined to the liver may benefit from embolisation or chemoembolisation. In the presence of disease not amenable to loco-regional therapy, median survival is only a few months. Current systemic therapy with cytotoxic chemotherapy induces relatively few responses and has no clear survival benefit. Current interest is focussed on the potential role of targeted therapies based on the key aspects of molecular pathogenesis of HCC, most notably sorafenib, an oral multikinase inhibitor. Recent developments discussed in this article demonstrate the potential benefits of this drug which seems destined to become first-line therapy for advanced HCC.

Systemic therapy for advanced hepatocellular carcinoma: past, present, and future

BACKGROUND

Although approximately 80% of hepatocellular carcinoma (HCC) cases occur in developing countries, the incidence of HCC in Western countries is on the rise due to the impact of hepatitis C. Challenges in developing effective therapies include the inherent chemoresistance of HCC, the pharmacologic challenges presented by a diseased liver, the presentation of most patients at advanced stages, and the difficulty in adequately measuring radiological response. While responses to traditional chemotherapeutic agents have been documented, significant survival benefit is debatable.

METHODS

The authors review the results of published clinical trials of systemic therapy and immunotherapy that have impacted the present treatment of HCC.

RESULTS

With recent progress in the elucidation of HCC molecular pathways, targeted agents show promise. The multikinase inhibitor sorafenib has provided survival benefit in patients with advanced HCC and well-preserved liver function. Sunitinib, bevacizumab, epidermal growth factor receptor inhibitors, and mammalian target of rapamycin (mTOR) inhibitors have shown activity in small patient cohorts. Immunotherapy appears to be a promising approach that can result in the regression of bulky, invasive cancer in some patients.

CONCLUSIONS

New agents with a variety of mechanisms of activity offer promising therapeutic options for patients with advanced HCC.

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.

MicroRNA-101 regulates expression of the v-fos FBJ murine osteosarcoma viral oncogene homolog (FOS) oncogene in human hepatocellular carcinoma

MicroRNAs (miRNAs) have recently been proposed as a versatile class of molecules involved in regulation of various biological processes. Although there is emerging evidence that some microRNAs can function as oncogenes or tumor suppressors, the specific role of miRNA in human hepatocellular carcinoma (HCC) is unclear at this point. In this study, we examined the microRNA expression profiles in a set of 20 human HCC specimens by miRNA microarray and quantitative real-time polymerase chain reaction. The results showed that among the 20 HCC samples analyzed, microRNA-101 was significantly down-regulated twofold or more (twofold to 20-fold) in 16 samples compared with the matching nontumoral liver tissues. Using both a luciferase reporter assay and Western blot analysis, we showed that microRNA-101 repressed the expression of v-fos FBJ murine osteosarcoma viral oncogene homolog (FOS) oncogene, a key component of the activator protein-1 (AP-1) transcription factor. Moreover, using a luciferase expression vector (pAP-1-Luc) driven by seven copies of an AP-1 cis-element, we observed that microRNA-101 expression inhibited phorbol 12-myristate 13-acetate (PMA)-induced AP-1 activity. In in vitro Matrigel invasion and Transwell migration assays, enhanced microRNA-101 expression inhibited the invasion and migration of cultured HCC cells, respectively. These findings suggest that microRNA-101 may play an important role in HCC.

CONCLUSION

MicroRNA-101, which is aberrantly expressed in HCC, could repress the expression of the FOS oncogene.

Molecular targeted therapy for hepatocellular carcinoma

A majority of patients with HCC present with advanced disease and are not candidates for liver transplantation, surgical resection, or regional therapy. Systemic cytotoxic chemotherapy agents are minimally effective, can have significant toxicity, and have not been shown to improve patient survival. Hepatocellular carcinomas are inherently chemotherapy-resistant tumors and are known to overexpress the multidrug resistance genes. Hepatocellular carcinoma is a very heterogeneous disease in terms of its etiology, molecular carcinogenic mechanisms, and biological behavior, which complicate our ability to identify rational molecular therapeutic "targets." Nearly every pathway involved in carcinogenesis is altered to some degree in HCC. Changes in hepatocyte growth factor expression, intracellular signaling, protease and matrix metalloproteinase expression, and oncogene expression are seen in HCC. The recent demonstration, in randomized clinical trials, of survival benefit for HCC patients treated with the oral agent sorafenib is encouraging progress in the development of molecularly targeted anticancer agents in HCC.

SOCS-3 is associated with vascular invasion and overall survival in hepatocellular carcinoma

AIMS

Alteration of the suppressor of cytokine signalling-3 (SOCS-3) has been observed in certain human cancers. However, the clinical role of this short-lived protein in hepatocellular carcinoma (HCC) is not well established. Therefore, we aimed to explore the potential role of SOCS-3 proteins in HCC.

METHODS

Paraffin embedded sections from 87 HCC patients were included in this study. The expression patterns of SOCS-3 proteins were analysed using immunohistochemistry and the results were correlated with clinicopathological characteristics and overall survival of the HCC patients.

RESULTS

The SOCS-3 expression of HCC lesions and the adjacent non-tumourous liver tissues was significantly correlated (p = 0.035), while the SOCS-3 expression in HCC lesions was significantly and positively correlated with vascular invasion and histological grading (p = 0.034 and 0.032, respectively). The Kaplan-Meier survival curve showed that the HCC patients with high SOCS-3 expression were associated with a poor overall survival rate in the HCC subgroup with positive vascular invasion (p = 0.014). Furthermore, a multivariate Cox regression model showed that SOCS-3 expression was also a significant determinant of the overall survival for HCC (p = 0.006).

CONCLUSIONS

Our results indicate that altered SOCS-3 expression is associated with the overall survival in a subset of HCC patients with positive vascular invasion. Constitutive and altered SOCS-3 expression may have potential roles in a subset of HCC patients.

c-Fos overexpression increases the proliferation of human hepatocytes by stabilizing nuclear Cyclin D1

AIM: To investigate the effect of stable c-Fos overexpression on immortalized human hepatocyte (IHH) proliferation.

METHODS: IHHs stably transfected with c-Fos (IHH-Fos) or an empty vector (IHH-C) were grown in medium supplemented with 1% serum or stimulated with 10% serum. Cell proliferation was assessed by cell counts, 3H-thymidine uptake and flow cytometry analyses. The levels of cell cycle regulatory proteins (Cyclin D1, E, A) cyclin dependent kinases (cdk) cdk2, cdk4, cdk6, and their inhibitors p15, p16, p21, p27, total and phosphorylated GSK-3β and epidermal growth factor receptor (EGF-R) were assayed by Western blotting. Analysis of Cyclin D1 mRNA levels was performed by reverse transcription-polymerase chain reaction and real-time polymerase chain reaction (PCR) analysis. Stability of Cyclin D1 was studied by cycloheximide blockade experiments.

RESULTS: Stable c-Fos overexpression increased cell proliferation under low serum conditions and resulted in a two-fold increase in [³H]-thymidine incorporation following serum addition. Cell cycle analysis by flow cytometry showed that c-Fos accelerated the cell cycle kinetics. Following serum stimulation, Cyclin D1 was more abundantly expressed in c-Fos overexpressing cells. Cyclin D1 accumulation did not result from increased transcriptional activation, but from nuclear stabilization. Overexpression of c-Fos correlated with higher nuclear levels of inactive phosphorylated GSK-3β, a kinase involved in Cyclin D1 degradation and higher levels of EGF-R mRNA, and EGF-R protein compared to IHH-C both in serum starved, and in serum stimulated cells. Abrogation of EGF-R signalling in IHH-Fos by treatment with AG1478, a specific EGF-R tyrosine kinase inhibitor, prevented the phosphorylation of GSK-3β induced by serum stimulation and decreased Cyclin D1 stability in the nucleus.

CONCLUSION: Our results clearly indicate a positive role for c-Fos in cell cycle regulation in hepatocytes. Importantly, we delineate a new mechanism by which c-Fos could contribute to hepatocarcinogenesis through stabilization of Cyclin D1 within the nucleus, evoking a new feature to c-Fos implication in hepatocellular carcinoma.

Systemic therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is currently the fifth most common solid tumor worldwide and the third leading cause of cancer-related death. Eighty percent of new cases occur in developing countries, but the incidence is rising in economically developed regions including Japan, Western Europe, and the United States. More than 80% of patients present with advanced or unresectable disease, and for those patients who do undergo resection, the recurrence rates can be as high as 50% at 2 years. Thus, a large number of patients will seek systemic therapy. Systemic cytotoxic chemotherapy is largely ineffective and can have significant toxicity in patients with underlying liver dysfunction. Newer biologic agents that target molecular abnormalities common to HCC may improve the clinical outcome in patients with HCC.

Ethanol inhibition of angiotensin II-stimulated Tyr705 and Ser727 STAT3 phosphorylation in cultured rat hepatocytes: relevance to activation of p42/44 mitogen-activated protein kinase

Angiotensin (Ang) II-stimulated phosphorylation of signal transducer and activator transcription (STAT) 3 in rat hepatocytes and the effects of ethanol on this activation were investigated. Angiotensin II (100 nM) stimulated Tyr705 and Ser727 phosphorylation of STAT3 and formation of sis-inducing factor complexes. In the presence of U-0126 (10microM), a p42/44 mitogen-activated protein kinase (MAPK) kinase inhibitor, Ang II further increased Tyr705 phosphorylation of STAT3 but completely abrogated Ser727 phosphorylation of STAT3. Inhibition of p42/44MAPK also increased STAT3 DNA-binding activity. Pretreatment with ethanol (100mM) for 24h resulted in decrease in Tyr705 phosphorylation of STAT3 by ethanol alone and inhibition of Tyr705 phosphorylation of STAT3 stimulated by Ang II. Although ethanol potentiates Ang II stimulated p42/44 MAPK activation in hepatocytes, ethanol inhibited Ser727 phosphorylation of STAT3 stimulated by Ang II. Angiotensin II-stimulated STAT3-binding activity was not significantly affected by ethanol treatment. These results suggest a negative regulation of Ang II-stimulated STAT3 tyrosine phosphorylation and STAT3-binding activity through p42/44 MAPK activation in hepatocytes. However, ethanol modulation of Ang II-stimulated STAT3 phosphorylation occurs by MAPK independent mechanisms. Ethanol potentiation of MAPK signaling without suppression of STAT3 function may modulate the course of alcoholic liver injury.

VEGF-D promotes tumor growth and lymphatic spread in a mouse model of hepatocellular carcinoma

Lymphatic spread is an important clinical determinant for the prognosis of hepatocellular carcinoma (HCC), but little is known about the control of lymphangiogenesis in HCC. We addressed expression and biological role of the pro-(lymph), angiogenic protein VEGF-D in this tumor entity. Using immunohistochemistry and in situ hybridization on specimens of HCC, cirrhotic and normal liver we found abundant expression of VEGF-D exclusively in the tumor cells. The cognate receptor VEGFR-3 was detected on blood and lymphatic vessels. By clinicopathological analysis VEGF-D expression was correlated with pT-stage of the primary, lymph node metastasis and lymphangiosis carcinomatosa. Three out of 4 human HCC cell lines expressed and secreted VEGF-D. To approach its biological function, VEGF-D deficient SKHep-1 cells were stably transfected with VEGF-D cDNA and effects on tumor progression were determined in vivo. Compared to mock-transfected controls, subcutaneous tumors derived from VEGF-D expressing cells were larger and more frequently metastasized to regional lymph nodes. VEGF-D expressing tumors exhibited increased microvessel density and increased abundance of peri- and intratumoral lymphatics, as assessed by immunostaining for CD31 and for LYVE-1 and/or podoplanin, respectively. Furthermore, coexpression of the soluble extracellular VEGFR-3 domain blocked VEGF-D-induced tumor growth and lymphatic spread via reduction of angiogenesis and lymphangiogenesis. In the orthotopic approach, VEGF-D expression resulted in an increased rate of intra- and extrahepatic as well as lymph node metastasis. In conclusion, our study suggests that expression of VEGF-D is involved in growth and lymphatic spread of HCC. Therefore, VEGF-D might represent a therapeutic target in HCC.

Systemic therapy for hepatocellular carcinoma: cytotoxic chemotherapy, targeted therapy and immunotherapy

Conventional cytotoxic chemotherapy has not provided clinical benefit or prolonged survival for patients with advanced HCC. This review summarizes the results of prospective clinical trials of several categories of systemic therapy, with emphasis on the more promising results from recent trials of biologically targeted therapeutic agents in HCC.

Inhibition of growth and metastasis of human hepatocellular carcinoma by antisense oligonucleotide targeting signal transducer and activator of transcription 3

PURPOSE

Hepatocellular carcinoma (HCC) is an aggressive malignancy and is a devastating clinical complication of chronic liver disease. Therapeutic options are limited mainly because the genetic and biochemical understanding of this disease remains fragmented. We intended to study the role of signal transducer and activator of transcription 3 (STAT3) aberrant signaling in HCC malignancy, and the therapeutic potential of inhibition of STAT3 expression for HCC.

EXPERIMENTAL DESIGN

A 2'-O-methoxyethylribose-modified phosphorothioate antisense oligonucleotide (ASO) was used to knock down STAT3 expression in different human HCC cell lines, including the highly metastatic HCCLM3 derived from orthotopic implantation and subsequent lung metastasis in athymic mice. The effects of STAT3 ASO treatment on HCC cells, metastasis, and animal survival following HCCLM3 orthotopic implantation were evaluated.

RESULTS

Specific suppression of phosphorylated STAT3 reduced its DNA-binding activity, inhibited the expression of vascular endothelial growth factor, survivin, matrix metalloproteinases 2 and 9, reduced cell proliferation and migratory potential, induced apoptosis in vitro, and inhibited intradermal angiogenesis and s.c. tumorigenesis upon injection in mice. In mice bearing orthotopically implanted HCCLM3, STAT3 inhibition following therapeutic treatment with STAT3 ASO reduced circulating vascular endothelial growth factor and basic fibroblast growth factor, decreased intratumor CD34-positive microvessel density, intrahepatic and intraperitoneal transmission, and lung metastasis. HCC tumor volume and weight were reduced and the survival time of mice bearing orthotopically xenografted HCC was approximately doubled in STAT3 ASO-treated mice (P < 0.05).

CONCLUSIONS

Constitutively activated STAT3 is essential for the growth, survival, and metastasis of HCC, suggesting that STAT3-targeted therapy may have utility for HCC.

Abrogation of constitutive STAT3 activity sensitizes human hepatoma cells to TRAIL-mediated apoptosis

BACKGROUND/AIMS

Signal transducer and activator of transcription 3 (STAT3) is constitutively activated and regulates cell growth and survival of various cancer cells. We investigated the anti-tumor effect of AG490, a Janus kinase 2 specific inhibitor, inhuman hepatoma cells.

METHODS

Effects of AG490 on STAT3 activation, on cell-growth and survival, and on the expression of cell-cycle- and apoptosis-related proteins were evaluated in Huh-1, Huh-7, HepG2 and Hep3B cells. Next, whether AG490 renders hepatoma cells susceptible to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was examined in vitro and in vivo.

RESULTS

Constitutively activated STAT3 through tyrosine phosphorylation was detected in all hepatoma cells. AG490 inhibited the phosphorylation of STAT3 and its activity. AG490 induced cell cycle arrest in Huh-1, Huh-7 and HepG2 through cyclin D1 downregulation, and induced marked apoptosis in Hep3B. AG490 downregulated at least one of the anti-apoptotic proteins, Bcl-xL, survivin or XIAP in all hepatoma cells. AG490 sensitized Huh-1, Huh-7 and HepG2 to TRAIL-induced apoptosis in vitro. Intraperitoneal injection of AG490, the combination of AG490 and TRAIL more greatly, repressed the growth of subcutaneous Huh-7 tumors in athymic mice.

CONCLUSIONS

Abrogation of constitutive activation of STAT3 by AG490 enhances the anti-tumor activity of TRAIL against human hepatoma cells.

Cell transformation and proteome alteration in QSG7701 cells transfected with hepatitis C virus non-structural protein 3

Persistent hepatitis C virus (HCV) infection can cause liver cirrhosis and hepatocellular carcinoma. Non-structural protein 3 (NS3), an important part of HCV, has been implicated in the life cycle of the virus and interacts with host cellular proteins. In this study, we investigated the effect of NS3 protein on cell tranformation and related protein alteration in human hepatocyte QSG7701 cells. The results indicated that stable expression of the NS3 protein in QSG7701 cells induced transformed characters with reduced population doubling time, anchorage-independent growth and tumor development. Fifteen differentially-expressed proteins were separated and identified using 2-D electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectrometry. Western blot analysis confirmed that the increase of phospho-p44/42 and phospho-p38 proteins was associated with transformed cells. These results supported the view that HCV NS3 protein plays a transforming role and provided some clues to elucidate the carcinogenesis mechanism of HCV-related hepatocellular carcinoma.

Safety, pharmacokinetics, and preliminary antitumor activity of sorafenib: a review of four phase I trials in patients with advanced refractory solid tumors

Sorafenib is an oral multikinase inhibitor that inhibits Raf serine/threonine kinases and receptor tyrosine kinases involved in tumor growth and angiogenesis. It has demonstrated preclinical and clinical activity in several tumor types. Sorafenib 400 mg twice daily (bid) has been approved in several countries worldwide for the treatment of renal cell carcinoma. This review summarizes key safety, pharmacokinetic, and efficacy data from four phase I, single-agent, dose-escalation studies with sorafenib in patients with advanced refractory solid tumors (n = 173). These trials followed different treatment regimens (7 days on/7 days off, n = 19; 21 days on/7 days off, n = 44; 28 days on/7 days off, n = 41; or continuous dosing, n = 69) to establish the optimum dosing schedule. Sorafenib was generally well tolerated; most adverse events were mild to moderate in severity up to the defined maximum-tolerated dose of 400 mg twice daily (bid). The most frequently reported drug-related adverse events at any grade included fatigue (40%), anorexia (35%), diarrhea (34%), rash/desquamation (27%), and hand-foot skin reaction (25%). Sorafenib demonstrated preliminary antitumor activity, particularly among patients with renal cell carcinoma or hepatocellular carcinoma: overall, two of 137 evaluable patients achieved partial responses and 38 (28%) had stable disease. Although there was high interpatient variability in plasma pharmacokinetics across these studies, this was not associated with an increased incidence or severity of toxicity. Preliminary studies suggest that phosphorylated extracellular signal-related kinase in tumor cells or peripheral blood lymphocytes may be a useful biomarker for measuring and, ultimately, predicting the effects of sorafenib. Based on these findings, continuous daily 400 mg bid sorafenib was chosen as the optimal regimen for phase II/III studies. Trials are ongoing in renal cell carcinoma, hepatocellular carcinoma, melanoma, and non-small cell lung cancer.

Immunohistochemical analysis of p53, cyclinD1, RB1, c-fos and N-ras gene expression in hepatocellular carcinoma in Iran

AIM: To study the effect of some genes especially those involved in cell cycle regulation on hepatocellular carcinoma.

METHODS: Paraffin-embedded tissue samples of 25 patients (18 males and 7 females) with hepatocellular carcinoma were collected from 22 pathology centers in Tehran during 2000-2001, and stained using immunohistochemistry method (avidin-biotin-peroxidase) for detection of p53, cyclinD1, RB1, c-fos and N-ras proteins.

RESULTS: Six (24%), 5 (20%), 12 (48%) and 2 samples (8%) were positive for p53, cyclinD1, C-fos and N-ras expression, respectively. Twenty-two (88%) samples had alterations in the G1 cell-cycle checkpoint protein expression (RB1 or cyclinD1). P53 positive samples showed a higher (9 times) risk of being positive for RB1 protein than p53 negative samples. Loss of expression of RB1 in association with p53 over-expression was observed in 4 (66.7%) of 6 samples. Loss of expression of RB1 was seen in all cyclinD1 positive, 20 (90.9%) N-ras negative, and 11 (50%) C-fos positive samples, respectively. CyclinD1 positive samples showed a higher (2.85 and 4.75 times) risk of being positive for c-fos and N-ras expression than cyclinD1 negative samples.

CONCLUSION: The expression of p53, RB1 and c-fos genes appears to have a key role in the pathogenesis of hepatocellular carcinoma in Iran. Simultaneous overexpression of these genes is significantly associated with their loss of expression during development of hepatocellular carcinoma.

Altered p-STAT3 (tyr705) expression is associated with histological grading and intratumour microvessel density in hepatocellular carcinoma

BACKGROUND

Constitutive activation of signal transducer and activator of transcription 3 at tyrosine residue 705 (p-STAT3 (tyr705)) has been associated with many types of human cancers. However, its potential roles and biological effects in hepatocellular carcinoma (HCC) are not well established.

AIM

To explore whether an altered p-STAT3 (tyr705) expression is associated with angiogenesis or proliferation and thereby plays a part in HCC development.

METHODS

Paraffin-wax-embedded sections from 69 patients with HCC were collected in this study. Using a semiquantitative immunohistochemical staining method, the expression patterns of p-STAT3 (tyr705) in both HCC lesions and the adjacent non-tumorous liver parenchyma were analysed. The results obtained were further correlated with intratumour microvessel density (MVD), Ki-67 expression, clinicopathological parameters and overall survival.

RESULTS

A strong p-STAT3 (tyr705) nuclear staining was observed in 49.3% of HCC lesions, but was reported only in 5.8% of the adjacent non-tumorous liver parenchyma (p<0.001). The expression of p-STAT3 (tyr705) in HCC lesions was significantly and positively correlated with the intratumour MVD (p = 0.002), but not with Ki-67 expression. No significant correlation of p-STAT3 (tyr705) was found in addition to histological grading (p = 0.019). Multivariate Cox regression analysis showed that p-STAT3 (tyr705) expression was a significant predictor of overall survival for HCC (p = 0.036), although the Kaplan-Meier survival curves showed no significant difference between the high and low p-STAT3 (tyr705) expression subgroups.

CONCLUSIONS

The results showed that p-STAT3 (tyr705) expression was closely correlated with histological grading and intratumour MVD in HCC. Thus, the potential role of p-STAT3 (tyr705) in HCC development may be through these correlations.

Altered p-STAT3 (tyr705) expression is associated with histological grading and intratumour microvessel density in hepatocellular carcinoma

BACKGROUND

Constitutive activation of signal transducer and activator of transcription 3 at tyrosine residue 705 (p-STAT3 (tyr705)) has been associated with many types of human cancers. However, its potential roles and biological effects in hepatocellular carcinoma (HCC) are not well established.

AIM

To explore whether an altered p-STAT3 (tyr705) expression is associated with angiogenesis or proliferation and thereby plays a part in HCC development.

METHODS

Paraffin-wax-embedded sections from 69 patients with HCC were collected in this study. Using a semiquantitative immunohistochemical staining method, the expression patterns of p-STAT3 (tyr705) in both HCC lesions and the adjacent non-tumorous liver parenchyma were analysed. The results obtained were further correlated with intratumour microvessel density (MVD), Ki-67 expression, clinicopathological parameters and overall survival.

RESULTS

A strong p-STAT3 (tyr705) nuclear staining was observed in 49.3% of HCC lesions, but was reported only in 5.8% of the adjacent non-tumorous liver parenchyma (p<0.001). The expression of p-STAT3 (tyr705) in HCC lesions was significantly and positively correlated with the intratumour MVD (p = 0.002), but not with Ki-67 expression. No significant correlation of p-STAT3 (tyr705) was found in addition to histological grading (p = 0.019). Multivariate Cox regression analysis showed that p-STAT3 (tyr705) expression was a significant predictor of overall survival for HCC (p = 0.036), although the Kaplan-Meier survival curves showed no significant difference between the high and low p-STAT3 (tyr705) expression subgroups.

CONCLUSIONS

The results showed that p-STAT3 (tyr705) expression was closely correlated with histological grading and intratumour MVD in HCC. Thus, the potential role of p-STAT3 (tyr705) in HCC development may be through these correlations.

Opportunities for targeted therapies in hepatocellular carcinoma

Hepatocellular cancer (HCC) is the fifth most common solid tumor worldwide, accounting for 500,000 new cases annually. Although less common in the United States, HCC is expected to increase in incidence over the next two decades largely because of the prevalence of hepatitis C virus infection. A majority of patients present with advanced disease and are not candidates for liver transplantation, surgical resection, or regional therapy. In 60% to 80% of patients with HCC, treatment is complicated by underlying liver cirrhosis and hepatic dysfunction. Systemic treatments are minimally effective, can have significant toxicity, and have not been shown to improve patient survival. New approaches targeting molecular abnormalities specific to HCC are needed to improve patient outcome. This review summarizes the state of knowledge of those key aspects of the molecular pathogenesis of HCC that may represent rational therapeutic targets in this disease. Relevant preclinical and clinical information on novel compounds directed toward abnormalities in HCC is reviewed.

Suppressed MKP-1 is an independent predictor of outcome in patients with hepatocellular carcinoma

OBJECTIVE

An increase in the activity of mitogen-activated protein kinases (MAPKs) has been correlated with a more malignant phenotype in several tumor models in vivo. This study was designed to clarify the expression of MKP-1 in surgically resected hepatocellular carcinoma (HCC).

METHODS

We reviewed the cases of 77 patients who had undergone initial liver resection for HCC without preoperative treatment. Immunohistochemical analysis of MKP-1 was performed on paraffin-embedded tissues. The correlation between MKP-1 expression and clinical outcome was investigated.

RESULTS

Tumor cells were immunohistochemically stained for MKP-1 expression, and the same levels as in normal hepatocytes were detected in 66 (85%) of 77 HCC patients, being decreased in 11 (15%) HCCs. Decreased MKP-1 expression significantly correlated with serum alpha-fetoprotein levels and tumor size (p<0.05). The disease-free survival rates in MKP-1-negative and -positive patients were 0 and 31.0% at 5 years, respectively (p<0.01). The survival rates after a surgical resection in MKP-1-negative and -positive patients were 18.2 and 65.5% at 5 years, respectively (p<0.01).

CONCLUSIONS

The MKP-1 expression in HCC was an independent prognostic factor for outcome in HCC patients. In the future, it will be useful to explore whether the phosphatase expression might account for the response to HCC treatments targeting at MAPK activation.

Reversing chemoresistance in cisplatin-resistant human ovarian cancer cells: A role of c-Jun NH2-terminal kinase 1

To investigate the role of activation of c-Jun NH2-terminal kinase 1 (JNK1) in mediating cisplatin-induced apoptosis and the possibility of induction of JNK activity in triggering relation to DNA damage and drug resistance. We investigated the difference of cisplatin-induced activation of JNK pathway and H2O2 alteration between cisplatin-sensitive human ovarian carcinoma cell line A2780 and its resistant variant A2780/DDP. JNK, p-JNK protein, and extracellular H2O2 levels were determined in both A2780 and A2780/DDP cells which were transfected with dominant negative allele of JNK and recombinant JNK1 separately. Both A2780 and A2780/DDP were treated with CDDP, the JNK pathway was activated and a prolonged JNK activation was maintained for at least 12 h in A2780, and only a transient activation (3 h) was detected in A2780/DDP in response to cisplatin treatment. Inhibition of JNK activity by transfection with a dominant negative allele of JNK blocked CDDP-induced apoptosis significantly in A2780 cells. Selective stimulation of the JNK pathway by lipofectamine-mediated delivery of recombinant JNK1 led to activation of c-Jun and decrease of extracellular H2O2, as well as apoptosis sensitization to CDDP in A2780/DDP cells. We concluded that JNK pathway might play an important role in mediating cisplatin-induced apoptosis in A2780 cells, and the duration of JNK activation might be critical in determining whether cells survive or undergo apoptosis. The resistance to CDDP can be reversed through activating c-Jun and decreasing extracellular generation of H2O2 by pcDNA3(FLAG)-JNK1-wt transfection in A2780/DDP cells.

Phase I clinical and pharmacokinetic study of the Novel Raf kinase and vascular endothelial growth factor receptor inhibitor BAY 43-9006 in patients with advanced refractory solid tumors

PURPOSE

BAY 43-9006 is a novel dual-action Raf kinase and vascular endothelial growth factor receptor inhibitor that inhibits tumor cell proliferation and angiogenesis. This study established the safety and pharmacokinetics of BAY 43-9006 in 69 patients with advanced refractory solid tumors.

PATIENTS AND METHODS

BAY 43-9006 (50 to 800 mg) was administered once or twice daily on a varying weekly schedule. Pharmacokinetic sampling was performed in all patients; preliminary tumor response was also assessed. The effect of BAY 43-9006 on phorbol myristate acetate-stimulated ERK phosphorylation in peripheral blood lymphocytes was studied using flow cytometry.

RESULTS

Mild to moderate diarrhea was the most common (55%) treatment-related adverse event. The maximum-tolerated dose was 400 mg bid continuous. Dose-limiting toxicities were grade 3 diarrhea and fatigue at 800 mg bid, and grade 3 skin toxicity at 600 mg bid. BAY 43-9006 pharmacokinetics were highly variable for single and multiple dosing, and toxicity did not appear to be dose dependent. Significant decreases of phorbol myristate acetate-stimulated ERK phosphorylation (P < .01) were identified at doses >/= 200 mg bid continuous. Forty-five patients were assessable for efficacy; one patient had a partial response (hepatocellular carcinoma at 400 mg bid continuous), 25 patients had stable disease, with eight lasting > 6 months and five for >12 months. Eighteen patients had progressive disease, and tumor response could not be evaluated in one patient.

CONCLUSION

Oral BAY 43-9006 was well tolerated and appeared to provide some clinical benefits. Based on the results of this study, BAY 43-9006 at 400 mg bid continuous is recommended for ongoing and future studies.

Bystander activity of Ad-mda7: Human MDA-7 protein kills melanoma cells via an IL-20 receptor-dependent but STAT3-independent mechanism

The melanoma differentiation-associated gene-7 (mda-7/IL24) is a unique member of the IL-10 family of cytokines, with ubiquitous tumor cell proapoptotic activity. Transduction of tumor or normal cells with the mda-7 gene results in secretion of glycosylated MDA-7 protein. Recent data indicate that secreted MDA-7 protein functions as a pro-Th1 cytokine and as a potent antiangiogenic molecule. MDA-7 protein binds two distinct type II cytokine heterodimeric receptor complexes, IL-20R1/IL-20R2 (type 1 IL-20R) and IL-22R1/IL-20R2 (type 2 IL-20R). In this study we analyzed the activity of glycosylated secreted MDA-7 against human melanoma cells. MDA-7 protein induces phosphorylation and nuclear translocation of STAT3 in melanoma cells via both type 1 and type 2 IL-20R. MDA-7 induces dose-dependent cell death in melanoma tumor cells. MDA-7 receptor engagement results in up-regulation of BAX and subsequent apoptosis induction; this effect is mediated by STAT3-independent signaling. Additional IL-10 family members (IL-10, -19, -20, and -22) also activate STAT3; however, these ligands do not activate death pathways in melanoma. In normal cells, MDA-7 can bind to its cognate receptors and induce phosphorylation of STAT3, without cytotoxic sequelae. This study defines a tumor-selective cytotoxic bystander role for secreted MDA-7 protein and identifies a novel receptor-mediated, STAT3-independent, and PKR-independent death pathway.