Expression of transforming growth factor alpha and epidermal growth factor receptor in human hepatocellular carcinoma

Signaling pathways in liver cancer: pathogenesis and targeted therapy

Liver cancer remains one of the most prevalent malignancies worldwide with high incidence and mortality rates. Due to its subtle onset, liver cancer is commonly diagnosed at a late stage when surgical interventions are no longer feasible. This situation highlights the critical role of systemic treatments, including targeted therapies, in bettering patient outcomes. Despite numerous studies on the mechanisms underlying liver cancer, tyrosine kinase inhibitors (TKIs) are the only widely used clinical inhibitors, represented by sorafenib, whose clinical application is greatly limited by the phenomenon of drug resistance. Here we show an in-depth discussion of the signaling pathways frequently implicated in liver cancer pathogenesis and the inhibitors targeting these pathways under investigation or already in use in the management of advanced liver cancer. We elucidate the oncogenic roles of these pathways in liver cancer especially hepatocellular carcinoma (HCC), as well as the current state of research on inhibitors respectively. Given that TKIs represent the sole class of targeted therapeutics for liver cancer employed in clinical practice, we have particularly focused on TKIs and the mechanisms of the commonly encountered phenomena of its resistance during HCC treatment. This necessitates the imperative development of innovative targeted strategies and the urgency of overcoming the existing limitations. This review endeavors to shed light on the utilization of targeted therapy in advanced liver cancer, with a vision to improve the unsatisfactory prognostic outlook for those patients.

The Loss of an Orphan Nuclear Receptor NR2E3 Augments Wnt/β-catenin Signaling via Epigenetic Dysregulation that Enhances Sp1-β catenin-p300 Interactions in Hepatocellular Carcinoma

The orphan nuclear receptor NR2E3 (Nuclear receptor subfamily 2 group E, Member 3) is an epigenetic player that modulates chromatin accessibility to activate p53 during liver injury. Nonetheless, a precise tumor suppressive and epigenetic role of NR2E3 in hepatocellular carcinoma (HCC) development remains unclear. HCC patients expressing low NR2E3 exhibit unfavorable clinical outcomes, aligning with heightened activation of the Wnt/β-catenin signaling pathway. The murine HCC models utilizing NR2E3 knockout mice consistently exhibits accelerated liver tumor formation accompanied by enhanced activation of Wnt/β-catenin signaling pathway and inactivation of p53 signaling. At cellular level, the loss of NR2E3 increases the acquisition of aggressive cancer cell phenotype and tumorigenicity and upregulates key genes in the WNT/β-catenin pathway with increased chromatin accessibility. This event is mediated through increased formation of active transcription complex involving Sp1, β-catenin, and p300, a histone acetyltransferase, on the promoters of target genes. These findings demonstrate that the loss of NR2E3 activates Wnt/β-catenin signaling at cellular and organism levels and this dysregulation is associated with aggressive HCC development and poor clinical outcomes. In summary, NR2E3 is a novel tumor suppressor with a significant prognostic value, maintaining epigenetic homeostasis to suppress the Wnt/β-catenin signaling pathway that promotes HCC development.

Advanced biosensors for nanomaterial-based detection of transforming growth factor alpha and beta, a class of major polypeptide regulators

Transforming growth factors (TGFs) regulate several cellular processes including, differentiation, growth, migration, extracellular matrix production, and apoptosis. TGF alpha (TGF-α) is a heterogeneous molecule containing 160 amino acid residues. It is a potent angiogenesis promoter that is activated by JAK-STAT signaling. Whereas TGF beta (TGF-β) consists of 390-412 amino acids. Smad and non-Smad signaling both occur in TGF beta. It is linked to immune cell activation, differentiation, and proliferation. It also triggers pre-apoptotic responses and inhibits cell proliferation. Both growth factors have a promising role in the development and homeostasis of tissues. Defects such as autoimmune diseases and cancer develop mechanisms to modulate checkpoints of the immune system resulting in altered growth factors profile. An accurate amount of these growth factors is essential for normal functioning, but an exceed or fall behind the normal level is alarming as it is linked to several disorders. This demands techniques for TGF-α and TGF-β profiling to effectively diagnose diseases, monitor their progression, and assess the efficacy of immunotherapeutic drugs. Quantitative detection techniques including the emergence of biosensing technology seem to accomplish the purpose. Until the present time, few biosensors have been designed in the context of TGF-α and TGF-β for disease detection, analyzing receptor binding, and interaction with carriers. In this paper, we have reviewed the physiology of transforming growth factor alpha and beta, including the types, structure, function, latent/active forms, signaling, and defects caused. It involves the description of biosensors on TGF-α and TGF-β, advances in technology, and future perspectives.

Near-infrared photoimmunotherapy in the models of hepatocellular carcinomas using cetuximab-IR700

Epidermal growth factor receptor (EGFR) has emerged as an important therapeutic target in many cancers, and overexpression of EGFR is frequently observed in hepatocellular carcinomas (HCCs). Near-infrared photoimmunotherapy (NIR-PIT) is a new anticancer treatment that selectively damages the cell membrane of cancer cells after NIR light-induced photochemical reaction of IR700, which is bound to a targeting antibody on the cell membrane. NIR-PIT using cetuximab-IR700 has already been approved in Japan, is under review by the US Food and Drug Administration (FDA) for advanced head and neck cancers, and its safety has been established. However, EGFR has not been investigated as a target in NIR-PIT in HCCs. Here, we investigate the application of NIR-PIT using cetuximab-IR700 to HCCs using xenograft mouse models of EGFR-expressing HCC cell lines, Hep3B, HuH-7, and SNU-449. In vitro NIR-PIT using EGFR-targeted cetuximab-IR700 killed cells in a NIR light dose-dependent manner. In vivo NIR-PIT resulted in a delayed growth compared with untreated controls. In addition, in vivo NIR-PIT in both models showed histological signs of cancer cell damage, such as cytoplasmic vacuolation and nuclear dysmorphism. A significant decrease in Ki-67 positivity was also observed after NIR-PIT, indicating decreased cancer cell proliferation. This study suggests that NIR-PIT using cetuximab-IR700 has potential for the treatment of EGFR-expressing HCCs.

Design, Synthesis, Anticancer Evaluation and Molecular Modeling Studies of New Thiazolidinone-Benzoate Scaffold as EGFR Inhibitors, Cell Cycle Interruption and Apoptosis Inducers in HepG2

Synthesis of new anticancer candidates with protein kinases inhibitory potency is a major goal of pharmaceutical science and synthetic research. This current work represents the synthesis of a series of substituted benzoate-thiazolidinones. Most prepared thiazolidinones were evaluated in vitro for their potential anticancer activity against three cell lines by MTT assay, and they found to be more effective against cancer cell lines with no harm toward normal cells. Thiazolidinones 5 c and 5 h were further evaluated to be kinase inhibitors against EGFR showing effective inhibitory impact (with IC50 value; 0.2±0.009 and 0.098±0.004 μM, for 5 c and 5 h, respectively). Furthermore, 5 c and 5 h have effects on cell cycle and apoptosis induction capability in HepG2 cell lines by DNA-flow cytometry analysis and annexin V-FITC apoptosis assay, respectively. The results showed that they have effect of disrupting the cell cycle and causing cell mortality by apoptosis in the treated cells. Moreover, molecular docking studies showed better binding patterns for 5 c and 5 h with the active site of the epidermal growth factor receptor (EGFR) protein kinase (PDB code 1M17). Finally, toxicity risk and physicochemical characterization by Osiris method was performed on most of the compounds, revealing excellent properties as possible drugs.

Critical Review in Designing Plant-Based Anticancer Nanoparticles against Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), accounting for 85% of liver cancer cases, continues to be the third leading cause of cancer-related deaths worldwide. Although various forms of chemotherapy and immunotherapy have been investigated in clinics, patients continue to suffer from high toxicity and undesirable side effects. Medicinal plants contain novel critical bioactives that can target multimodal oncogenic pathways; however, their clinical translation is often challenged due to poor aqueous solubility, low cellular uptake, and poor bioavailability. Nanoparticle-based drug delivery presents great opportunities in HCC therapy by increasing selectivity and transferring sufficient doses of bioactives to tumor areas with minimal damage to adjacent healthy cells. In fact, many phytochemicals encapsulated in FDA-approved nanocarriers have demonstrated the ability to modulate the tumor microenvironment. In this review, information about the mechanisms of promising plant bioactives against HCC is discussed and compared. Their benefits and risks as future nanotherapeutics are underscored. Nanocarriers that have been employed to encapsulate both pure bioactives and crude extracts for application in various HCC models are examined and compared. Finally, the current limitations in nanocarrier design, challenges related to the HCC microenvironment, and future opportunities are also discussed for the clinical translation of plant-based nanomedicines from bench to bedside.

EGFR inhibition reverses resistance to lenvatinib in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. Lenvatinib is approved as a first-line treatment for unresectable HCC. The therapeutic duration of lenvatinib is limited by resistance, but the underlying mechanism is unclear. To establish lenvatinib-resistant cells, Hep3B cells were initially treated with 3 µM lenvatinib. The concentration was gradually increased by 1 µM or 0.5 µM per week and it reached to 7.5 µM 2 months after the initial exposure to lenvatinib. The biological characteristics of these cells were analyzed by ERK activation in the MAPK signaling pathway and a human phospho‐receptor tyrosine kinase (RTK) antibody array. Factors possibly related to lenvatinib resistance were analyzed using inhibitors, and cell proliferation was analyzed. We established lenvatinib-resistant HCC cells (LR cells) by long-term exposure to lenvatinib. Lenvatinib reduced ERK activation in the parent cells, but not in the LR cells. RTK array analysis showed that the activities of EGFR and insulin-like growth factor 1 receptor (IGF1R)/insulin receptor (INSR) were significantly increased in LR cells, whereas the activities of other RTKs were unchanged. Erlotinib, a widely used EGFR inhibitor, downregulated ERK activation in LR cells. The proliferation of LR cells will also be affected when lenvatinib is combined with erlotinib to treat LR cells. In contrast, inhibition of IGFR/INSR did not affect ERK activation or cell proliferation. Scavenging of reactive oxygen species (ROS) ameliorated the enhanced EGFR activation in LR cells. Lenvatinib resistance was induced by enhanced EGFR activation, possibly via ROS accumulation, in lenvatinib- resistant cells. These findings may enable the development of lenvatinib combination therapies for HCC.

Muscarinic Receptors Associated with Cancer

Simple Summary

Recently, cancer research has described the presence of the cholinergic machinery, specifically muscarinic receptors, in a wide variety of cancers due to their activation and signaling pathways associated with tumor progression and metastasis, providing a wide overview of their contribution to different cancer formation and development for new antitumor targets. This review focused on determining the molecular signatures associated with muscarinic receptors in breast and other cancers and the need for pharmacological, molecular, biochemical, technological, and clinical approaches to improve new therapeutic targets.

Abstract

Cancer has been considered the pathology of the century and factors such as the environment may play an important etiological role. The ability of muscarinic agonists to stimulate growth and muscarinic receptor antagonists to inhibit tumor growth has been demonstrated for breast, melanoma, lung, gastric, colon, pancreatic, ovarian, prostate, and brain cancer. This work aimed to study the correlation between epidermal growth factor receptors and cholinergic muscarinic receptors, the survival differences adjusted by the stage clinical factor, and the association between gene expression and immune infiltration level in breast, lung, stomach, colon, liver, prostate, and glioblastoma human cancers. Thus, targeting cholinergic muscarinic receptors appears to be an attractive therapeutic alternative due to the complex signaling pathways involved.

Expression of Pregnancy Up-regulated Non-ubiquitous Calmodulin Kinase (PNCK) in Hepatocellular Carcinoma

BACKGROUND/AIM

Pregnancy up-regulated non-ubiquitous calmodulin kinase (PNCK) is a member of calmodulin kinase, and overexpression of PNCK with involvement in carcinogenesis have been reported in HER-2 amplified breast cancer, clear cell renal cell carcinoma and nasopharygeal carcinoma. However, the expression of PNCK and its clinical implication have not been elucidated in hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

We investigated PNCK expression at both the protein and mRNA level using immunohistochemistry (IHC) and microarray gene expression profiling in HCC tissue samples, and evaluated its association with clinicopathological parameters and their potential prognostic significance.

RESULTS

High PNCK protein expression and high PNCK mRNA level was observed in 61.7% and 34.7% of total HCC cases, respectively. PNCK mRNA level was higher in tumor tissues than in background non-tumor tissues, and significantly correlated with protein expression by IHC. High PNCK expression was associated with higher Edmondson grade, intrahepatic metastasis, microvascular invasion and higher AFP levels. Patients with high PNCK expression showed shorter recurrence-free survival and disease-specific survival, and high mRNA expression of PNCK was an independent prognostic factor in disease-specific survival.

CONCLUSION

Up-regulation of PNCK expression as well as its association with poor prognosis was demonstrated in HCC. PNCK might be a prognostic biomarker of HCC, and could be a potential candidate therapeutic target.

Bioinformatic Analysis of Hepatocellular Carcinoma Cell Lines to the Efficacy of Nimotuzumab

Introduction

Hepatocellular carcinoma (HCC) continues to be a cancer with rising incidence, high mortality, and recurrence rate. The therapeutic effects on HCC are not satisfactory currently. Epidermal growth factor receptor (EGFR) is an important factor, while anti-EGFR agencies have not shown ideal results in HCC.

Materials and Methods

We tested efficacy of nimotuzumab and EGFR expression on cell surface in six HCC cell lines (Hep 3B2.1–7, Li-7, PLC/PRF/5, SK-HEP-1, SNU-182, and SNU-387). Then, we analyzed RNA sequences of every cell line and performed a bioinformatic analysis. Differentially expressed genes (DEGs) were analyzed. The data, TCGA-LIHC from The Cancer Genome Atlas (TCGA) and GSE102079 from Gene Expression Omnibus (GEO), were used to analyse DEGs of Hoshida subclass.

Results

Hep 3B2.1–7 and PLC/PRF/5 were sensitive to nimotuzumab whereas Li-7, SK-HEP-1, SNU-182, and SNU-387 cell lines were resistant. Then, we compared the DEGs between sensitive and resistant group cell lines. We enriched DEGs in GO and KEGG and performed GSEA in each group. Genes in two groups did not show obvious different expressions in EGFR pathways, while Hoshida subclass of HCC seemed to associate with the efficacy of nimotuzumab in that S2 and S3 showed better therapeutic effect than S1. Therefore, we analyzed genes in human tumor samples which were from TCGA-LIHC and GSE102079. We found that COL1A1, COL1A2, COL3A1, and MMP9 were the focus DEGs of S1 and S2 & S3 related to EGFR.

Conclusion

The efficacy of nimotuzumab in HCC did not show direct relevance with EGFR protein expression and EGFR-related pathway. However, efficacy could associate with Hoshida subclass of HCC. Three ECM genes (COL1A1, COL1A2, COL3A1) and MMP9 were paid attention, as they might play important roles in the curative effect of nimotuzumab in HCC.

Epidermal Growth Factor Receptor Expression and Resistance Patterns to Targeted Therapy in Non-Small Cell Lung Cancer: A Review

Globally, lung cancer is the leading cause of cancer-related death. The majority of non-small cell lung cancer (NSCLC) tumours express epidermal growth factor receptor (EGFR), which allows for precise and targeted therapy in these patients. The dysregulation of EGFR in solid epithelial cancers has two distinct mechanisms: either a kinase-activating mutation in EGFR (EGFR-mutant) and/or an overexpression of wild-type EGFR (wt-EGFR). The underlying mechanism of EGFR dysregulation influences the efficacy of anti-EGFR therapy as well as the nature of resistance patterns and secondary mutations. This review will critically analyse the mechanisms of EGFR expression in NSCLC, its relevance to currently approved targeted treatment options, and the complex nature of secondary mutations and intrinsic and acquired resistance patterns in NSCLC.

Integrated stress response in hepatitis C promotes Nrf2-related chaperone-mediated autophagy: A novel mechanism for host-microbe survival and HCC development in liver cirrhosis

The molecular mechanism(s) how liver damage during the chronic hepatitis C virus (HCV) infection evolve into cirrhosis and hepatocellular carcinoma (HCC) is unclear. HCV infects hepatocyte, the major cell types in the liver. During infection, large amounts of viral proteins and RNA replication intermediates accumulate in the endoplasmic reticulum (ER) of the infected hepatocyte, which creates a substantial amount of stress response. Infected hepatocyte activates a different type of stress adaptive mechanisms such as unfolded protein response (UPR), antioxidant response (AR), and the integrated stress response (ISR) to promote virus-host cell survival. The hepatic stress is also amplified by another layer of innate and inflammatory response associated with cellular sensing of virus infection through the production of interferon (IFN) and inflammatory cytokines. The interplay between various types of cellular stress signal leads to different forms of cell death such as apoptosis, necrosis, and autophagy depending on the intensity of the stress and nature of the adaptive cellular response. How do the adaptive cellular responses decode such death programs that promote host-microbe survival leading to the establishment of chronic liver disease? In this review, we discuss how the adaptive cellular response through the Nrf2 pathway that promotes virus and cell survival. Furthermore, we provide a glimpse of novel stress-induced Nrf2 mediated compensatory autophagy mechanisms in virus-cell survival that degrade tumor suppressor gene and activation of oncogenic signaling during HCV infection. Based on these facts, we hypothesize that the balance between hepatic stress, inflammation and different types of cell death determines liver disease progression outcomes. We propose that a more nuanced understanding of virus-host interactions under excessive cellular stress may provide an answer to the fundamental questions why some individuals with chronic HCV infection remain at risk of developing cirrhosis, cancer and some do not.

Hepatocellular Carcinoma Mechanisms Associated with Chronic HCV Infection and the Impact of Direct-Acting Antiviral Treatment

Hepatitis C virus (HCV) infection is the major risk factor for liver cirrhosis and hepatocellular carcinoma (HCC). The mechanisms of HCC initiation, growth, and metastasis appear to be highly complex due to the decade-long interactions between the virus, immune system, and overlapping bystander effects of host metabolic liver disease. The lack of a readily accessible animal model system for HCV is a significant obstacle to understand the mechanisms of viral carcinogenesis. Traditionally, the primary prevention strategy of HCC has been to eliminate infection by antiviral therapy. The success of virus elimination by antiviral treatment is determined by the SVR when the HCV is no longer detectable in serum. Interferon-alpha (IFN-α) and its analogs, pegylated IFN-α (PEG-IFN-α) alone with ribavirin (RBV), have been the primary antiviral treatment of HCV for many years with a low cure rate. The cloning and sequencing of HCV have allowed the development of cell culture models, which accelerated antiviral drug discovery. It resulted in the selection of highly effective direct-acting antiviral (DAA)-based combination therapy that now offers incredible success in curing HCV infection in more than 95% of all patients, including those with cirrhosis. However, several emerging recent publications claim that patients who have liver cirrhosis at the time of DAAs treatment face the risk of HCC occurrence and recurrence after viral cure. This remains a substantial challenge while addressing the long-term benefit of antiviral medicine. The host-related mechanisms that drive the risk of HCC in the absence of the virus are unknown. This review describes the multifaceted mechanisms that create a tumorigenic environment during chronic HCV infection. In addition to the potential oncogenic programming that drives HCC after viral clearance by DAAs, the current status of a biomarker development for early prediction of cirrhosis regression and HCC detection post viral treatment is discussed. Since DAAs treatment does not provide full protection against reinfection or viral transmission to other individuals, the recent studies for a vaccine development are also reviewed.

Chaperone-Mediated Autophagy in the Liver: Good or Bad?

Hepatitis C virus (HCV) infection triggers autophagy processes, which help clear out the dysfunctional viral and cellular components that would otherwise inhibit the virus replication. Increased cellular autophagy may kill the infected cell and terminate the infection without proper regulation. The mechanism of autophagy regulation during liver disease progression in HCV infection is unclear. The autophagy research has gained a lot of attention recently since autophagy impairment is associated with the development of hepatocellular carcinoma (HCC). Macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA) are three autophagy processes involved in the lysosomal degradation and extracellular release of cytosolic cargoes under excessive stress. Autophagy processes compensate for each other during extreme endoplasmic reticulum (ER) stress to promote host and microbe survival as well as HCC development in the highly stressed microenvironment of the cirrhotic liver. This review describes the molecular details of how excessive cellular stress generated during HCV infection activates CMA to improve cell survival. The pathological implications of stress-related CMA activation resulting in the loss of hepatic innate immunity and tumor suppressors, which are most often observed among cirrhotic patients with HCC, are discussed. The oncogenic cell programming through autophagy regulation initiated by a cytoplasmic virus may facilitate our understanding of HCC mechanisms related to non-viral etiologies and metabolic conditions such as uncontrolled type II diabetes. We propose that a better understanding of how excessive cellular stress leads to cancer through autophagy modulation may allow therapeutic development and early detection of HCC.

MAT2B mediates invasion and metastasis by regulating EGFR signaling pathway in hepatocellular carcinoma

The poor prognosis of hepatocellular carcinoma (HCC) patients is mainly due to cancer metastasis. Methionine adenosyltransferase 2β (MAT2B) encodes a regulatory subunit (β) for methionine adenosyltransferase. Previous studies reveal that MAT2B provides a growth advantage for HCC, but its role in metastasis is unknown. This study showed that both in the xenograft zebra fish model and in the lung metastasis model in nude mice, the stable inhibition of MAT2B could suppress the metastasis of HCC cancer cells. Silencing of MAT2B in HCC cell lines could remarkably inhibit migration and invasion. By analysis of human phospho-kinase array membranes, we found several differentially expressed proteins, including phosphor-AKT, phospho-EGFR, phospho-Src family, phospho-FAK, phospho-STAT3 and phospho-ERK. We further confirmed the change of these EGFR pathway-related proteins was in accordance with MAT2B expression pattern through immunoblotting test. Finally, we found that MAT2B was overexpressed in HCC caner tissues and correlated with poor prognosis for HCC patients in clinical manifestation. Our study demonstrated that silencing of MAT2B could suppress liver cancer cell migration and invasion through the inhibition of EGFR signaling, which suggested that MAT2B might serve as a new prognostic marker and therapeutic target for HCC.

Rethink of EGFR in Cancer With Its Kinase Independent Function on Board

The epidermal growth factor receptor (EGFR) is one of most potent oncogenes that are commonly altered in cancers. As a receptor tyrosine kinase, EGFR's kinase activity has been serving as the primary target for developing cancer therapeutics, namely the EGFR inhibitors including small molecules targeting its ATP binding pocket and monoclonal antibodies targeting its ligand binding domains. EGFR inhibitors have produced impressive therapeutic benefits to responsive types of cancers. However, acquired and innate resistances have precluded current anti-EGFR agents from offering sustainable benefits to initially responsive cancers and benefits to EGFR-positive cancers that are innately resistant. Recent years have witnessed a realization that EGFR possesses kinase-independent (KID) pro-survival functions in cancer cells. This new knowledge has offered a different angle of understanding of EGFR in cancer and opened a new avenue of targeting EGFR for cancer therapy. There are already many excellent reviews on the role of EGFR with a focus on its kinase-dependent functions and mechanisms of resistance to EGFR targeted therapies. The present opinion aims to initiate a fresh discussion about the function of EGFR in cancer cells by laying out some unanswered questions pertaining to EGFR in cancer cells, by rethinking the unmet therapeutic challenges from a view of EGFR's KID function, and by proposing novel approaches to target the KID functions of EGFR for cancer treatment.

Immunohistochemical Expression of Epidermal Growth Factor Receptor in Hepatocellular Carcinoma

INTRODUCTION

Epidermal growth factor receptor (EGFR) signaling plays an important role in various cancers, including hepatocellular carcinoma (HCC). We aimed to evaluate immunoexpression of EGFR in HCC and surrounding non-tumor liver tissue and to correlate it to multiple clinicopathologic data.

MATERIAL AND METHODS

We analyzed 60 patients with HCC for multiple clinicopathologic characteristics and survival. Presence of the immunosignal and the percentage of positive tumor cells at the whole tumor tissue sample and adjacent cirrhotic liver tissue were semi-quantitatively determined.

RESULTS

Nineteen patients (31.67%) were female and 41 (68.33%) were male ranging in age from 31 to 85 years, median 61.88±10.51. Mean survival time for female patients was 8.86±1.76 months, for male 13.03±1.50 months and overall survival was 11.6051±1.19 months. The most patients had: T2 status (41.67%), no enlarged lymph nodes (90%), vascular invasion (63.33%) and well differentiated (43.33%) tumors. EGFR immunoexpression was determined in range from 0% to 100% in both tumor and non-tumor tissue with mean value of 39.58% in tumor and 86.86% in cirrhotic tissue (p<0.00). Higher percent of tumor EGFR positive cells were found in cases with higher T status, higher levels of AFP and poorly differentiated carcinoma, but not significantly. Lower percent of tumor EGFR positive cells were found in patients with vascular invasion and enlarged lymph nodes, but also not significantly. EGFR expression in tumor tissue significantly influenced survival of the patients (p<0.05).

CONCLUSION

The study showed that expression of EGFR in lower percentage of tumor cells was associated to favorable prognosis, making it a potential prognostic marker and therapeutic target.

Demethylation-Induced Overexpression of Shc3 Drives c-Raf-Independent Activation of MEK/ERK in HCC

Invasion and intrahepatic metastasis are major factors of poor prognosis in patients with hepatocellular carcinoma (HCC). In this study, we show that increased Src homolog and collagen homolog 3 (Shc3) expression in malignant HCC cell lines associate with HCC invasion and metastasis. Shc3 (N-Shc) was significantly upregulated in tumors of 33 HCC patient samples as compared with adjacent normal tissues. Further analysis of 52 HCC patient samples showed that Shc3 expression correlated with microvascular invasion, cancer staging, and poor prognosis. Shc3 interacted with major vault protein, resulting in activation of MEK1/2 and ERK1/2 independently of Shc1 and c-Raf; this interaction consequently induced epithelial-mesenchymal transition and promoted HCC cell proliferation and metastasis. The observed increase in Shc3 levels was due to demethylation of its upstream promoter, which allowed c-Jun binding. In turn, Shc3 expression promoted c-Jun phosphorylation in a positive feedback loop. Analysis of metastasis using a tumor xenograft mouse model further confirmed the role of Shc3 in vivo Taken together, our results indicate the importance of Shc3 in HCC progression and identify Shc3 as a novel biomarker and potential therapeutic target in HCC.Significance: Ectopic expression of Shc3 forms a complex with MVP/MEK/ERK to potentiate ERK activation and plays an important role in sorafinib resistance in HCC. Cancer Res; 78(9); 2219-32. ©2018 AACR.

Overexpression of SCAMP3 is an indicator of poor prognosis in hepatocellular carcinoma

SCAMP3, an isoform of the secretory carrier membrane proteins (SCAMPs) family, is a membrane-trafficking protein involved in endosome transport. Previous microarray data showed that SCAMP3 mRNA is highly expressed in hepatocellular carcinoma (HCC). In this study, the expression and clinical significance of SCAMP3 in 100 pairs of HCC and adjacent normal tissue were investigated. siRNA transfection was performed to silence SCAMP3 expression in HCC cells. The MTS assay and flow cytometry were used to detect the proliferation, cell cycle progression of HCC cells. Compared with adjacent normal tissues, SCAMP3 expression was dramatically increased in HCC tissues demonstrated by Western blotting (P < 0.05). In immunohistochemistry, compared with the adjacent normal tissues, SCAMP3 was detected in 96% of the HCC samples with a significant increase in intensity and number of stained cells (P < 0.05). Also, high SCAMP3 expression was found in 86% of the HCC samples (P < 0.05). The increased SCAMP3 expression was significantly correlated with vascular invasion (P = 0.004) and tumor stage (P = 0.001). Univariate and multivariate survival analyses showed that the expression of SCAMP3 was an independent prognostic factor of overall survival of HCC patients. Knockdown of SCAMP3 expression led to suppression of cell proliferation and blockage of cell cycle of HCC cells. In conclusion, our present study suggested that SCAMP3 may serve as a promising prognostic biomarker and molecular target of HCC and further investigation is warranted.

Hepatocellular carcinoma treated with anti-epidermal growth factor receptor antibody nimotuzumab: A case report

RATIONALE

Molecular targeted therapy provides new ideas and hope for the treatment of hepatocellular cancer. Epidermal growth factor receptor (EGFR) is closely related to tumor cell proliferation, apoptosis, invasion, and metastasis.

PATIENT CONCERNS

Several reports indicate that the EGFR is expressed frequently in hepatocellular carcinoma (HCC), thus targeting EGFR research has become a hot topic to explore the treatment of HCC patient.

DIAGNOSES

Anti-EGFR might serve as a potential therapeutic agent, especially for patients with HCC who are unable to tolerate chemotherapy and surgery.

INTERVENTIONS

Although phase II open-label study of cetuximab in unresectable HCC was negative, the clinical relevance of this report by Song et al which is based on a single patient is questionable.

OUTCOMES

We for the first time report that nimotuzumab (an anti-EGFR mAb) resulted in a complete remission (CR) in an 87-year-old patient with HCC. The patient was in B stage according to Barcelona center staging criteria and his liver function was Child-Pugh B grade.

LESSONS

Our case suggested that anti-EGFR mAbs might be potential therapeutic options for HCC.

The identification of key genes and pathways in hepatocellular carcinoma by bioinformatics analysis of high-throughput data

Liver cancer is a serious threat to public health and has fairly complicated pathogenesis. Therefore, the identification of key genes and pathways is of much importance for clarifying molecular mechanism of hepatocellular carcinoma (HCC) initiation and progression. HCC-associated gene expression dataset was downloaded from Gene Expression Omnibus database. Statistical software R was used for significance analysis of differentially expressed genes (DEGs) between liver cancer samples and normal samples. Gene Ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, based on R software, were applied for the identification of pathways in which DEGs significantly enriched. Cytoscape software was for the construction of protein–protein interaction (PPI) network and module analysis to find the hub genes and key pathways. Finally, weighted correlation network analysis (WGCNA) was conducted to further screen critical gene modules with similar expression pattern and explore their biological significance. Significance analysis identified 1230 DEGs with fold change >2, including 632 significantly down-regulated DEGs and 598 significantly up-regulated DEGs. GO term enrichment analysis suggested that up-regulated DEG significantly enriched in immune response, cell adhesion, cell migration, type I interferon signaling pathway, and cell proliferation, and the down-regulated DEG mainly enriched in response to endoplasmic reticulum stress and endoplasmic reticulum unfolded protein response. KEGG pathway analysis found DEGs significantly enriched in five pathways including complement and coagulation cascades, focal adhesion, ECM–receptor interaction, antigen processing and presentation, and protein processing in endoplasmic reticulum. The top 10 hub genes in HCC were separately GMPS, ACACA, ALB, TGFB1, KRAS, ERBB2, BCL2, EGFR, STAT3, and CD8A, which resulted from PPI network. The top 3 gene interaction modules in PPI network enriched in immune response, organ development, and response to other organism, respectively. WGCNA revealed that the confirmed eight gene modules significantly enriched in monooxygenase and oxidoreductase activity, response to endoplasmic reticulum stress, type I interferon signaling pathway, processing, presentation and binding of peptide antigen, cellular response to cadmium and zinc ion, cell locomotion and differentiation, ribonucleoprotein complex and RNA processing, and immune system process, respectively. In conclusion, we identified some key genes and pathways closely related with HCC initiation and progression by a series of bioinformatics analysis on DEGs. These screened genes and pathways provided for a more detailed molecular mechanism underlying HCC occurrence and progression, holding promise for acting as biomarkers and potential therapeutic targets.

EGFR Signaling in Liver Diseases

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase that is activated by several ligands leading to the activation of diverse signaling pathways controlling mainly proliferation, differentiation, and survival. The EGFR signaling axis has been shown to play a key role during liver regeneration following acute and chronic liver damage, as well as in cirrhosis and hepatocellular carcinoma (HCC) highlighting the importance of the EGFR in the development of liver diseases. Despite the frequent overexpression of EGFR in human HCC, clinical studies with EGFR inhibitors have so far shown only modest results. Interestingly, a recent study has shown that in human HCC and in mouse HCC models the EGFR is upregulated in liver macrophages where it plays a tumor-promoting function. Thus, the role of EGFR in liver diseases appears to be more complex than what anticipated. Further studies are needed to improve the molecular understanding of the cell-specific signaling pathways that control disease development and progression to be able to develop better therapies targeting major components of the EGFR signaling network in selected cell types. In this review, we compiled the current knowledge of EGFR signaling in different models of liver damage and diseases, mainly derived from the analysis of HCC cell lines and genetically engineered mouse models (GEMMs).

Loss of EGF-dependent cell proliferation ability on radioresistant cell HepG2-8960-R

Acquired radioresistance of cancer cells interferes with radiotherapy and increases the probability of cancer recurrence. HepG2-8960-R, which is one of several clinically relevant radioresistant (CRR) cell lines, has a high tolerance to the repeated clinically relevant doses of X-ray radiation. In this study, HepG2-8960-R had slightly lower cell proliferation ability than HepG2 in the presence of FBS. In particular, epidermal growth factor (EGF) hardly enhanced cell proliferation and DNA synthesis in HepG2-8960-R. Additionally, EGF could not induce the activation of Erk1/2, because the expression of EGF receptor (EGFR) protein decreased in HepG2-8960-R in accordance with the methylation of the EGFR promoter region. Therefore, cetuximab did not inhibit HepG2-8960-R cell proliferation. Our study showed that HepG2-8960-R had radioresistant and cetuximab-resistant abilities.

Entrapment of an EGFR inhibitor into nanostructured lipid carriers (NLC) improves its antitumor activity against human hepatocarcinoma cells

Background

In hepatocellular carcinoma (HCC), different signaling pathways are de-regulated, and among them, the expression of the epidermal growth factor receptor (EGFR). Tyrphostin AG-1478 is a lipophilic low molecular weight inhibitor of EGFR, preferentially acting on liver tumor cells. In order to overcome its poor drug solubility and thus improving its anticancer activity, it was entrapped into nanostructured lipid carriers (NLC) by using safe ingredients for parenteral delivery.

Results

Nanostructured lipid carriers (NLC) carrying tyrphostin AG-1478 were prepared by using the nanoprecipitation method and different matrix compositions. The best system in terms of mean size, PDI, zeta potential, drug loading and release profile was chosen to evaluate the anti-proliferative effect of drug-loaded NLC versus free drug on human hepatocellular carcinoma HA22T/VGH cells.

Conclusions

Thanks to the entrapment into NLC systems, tyrphostin AG-1478 shows an enhanced in vitro anti-tumor activity compared to free drug. These finding raises hope of future drug delivery strategy of tyrphostin AG-1478 -loaded NLC targeted to the liver for the HCC treatment.

Systemic therapy of hepatocellular carcinoma: Current status and future perspectives

The management of hepatocellular carcinoma (HCC) has substantially changed in the past few decades, the introduction of novel therapies (such as sorafenib) have improved patient survival. Nevertheless, HCC remains the third most common cause of cancer-related deaths worldwide. Decision-making largely relies on evidence-based criteria, as showed in the US and European clinical practice guidelines, which endorse five therapeutic recommendations:resection; transplantation; radiofrequency ablation; chemoembolization; and sorafenib. Many molecularly targeted agents that inhibit angiogenesis, epidermal growth factor receptor, and mammalian target of rapamycin are at different stages of clinical development in advanced HCC. Future research should continue to unravel the mechanism of hepatocarcinogenesis and to identify key relevant molecular targets for therapeutic intervention. Identification and validation of potential surrogate and predictive biomarkers hold promise to individualize patient’s treatment to maximize clinical benefit and minimize the toxicity and cost of targeted agents.

The EGFR signalling system in the liver: from hepatoprotection to hepatocarcinogenesis

The liver displays an outstanding wound healing and regenerative capacity unmatched by any other organ. This reparative response is governed by a complex network of inflammatory mediators, growth factors and metabolites that are set in motion in response to hepatocellular injury. However, when liver injury is chronic, these regenerative mechanisms become dysregulated, facilitating the accumulation of genetic alterations leading to unrestrained cell proliferation and the development of hepatocellular carcinoma (HCC). The epidermal growth factor receptor (EGFR or ErbB1) signaling system has been identified as a key player in all stages of the liver response to injury, from early inflammation and hepatocellular proliferation to fibrogenesis and neoplastic transformation. The EGFR system engages in extensive crosstalk with other signaling pathways, acting as a true signaling hub for other growth factors, cytokines and inflammatory mediators. Here, we briefly review essential aspects of the biology of the EGFR, the other ErbB receptors, and their ligands in liver injury, regeneration and HCC development. Some aspects of the preclinical and clinical experience with EGFR therapeutic targeting in HCC are also discussed.

Combination of cetuximab and rapamycin enhances the therapeutic efficacy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most deadly cancers worldwide. It is well known that the activation of PI3K/AKT/mTOR and the Ras/MAPK signaling pathway plays a critical role in cellular metabolism, growth and proliferation, and its inhibitors have been used as therapeutic drugs for hepatocellular carcinoma. Cetuximab, a chimerical monoclonal EGFR IgG1 antibody, can block the binding of EGF or other ligands to EGFR and thus inhibit ligands-induced receptor phosphorylation. In the present study, we found that rapamycin could enhance the antiproliferation effect of cetuximab in both HepG2 cells and Huh-7 cells and arrest the cell cycle. Cetuximab in combination with rapamycin had synergistic effects on inhibiting the phosphrylation of proteins in PI3K/AKT/mTOR and Ras/MAPK signaling pathway. Combination of cetuximab with rapamycin treatment significantly suppressed the HCC development in HepG2 cells-xenografted mice and improved the survival. Cetuximab and rapamycin inhibited the growth of HCC both in vitro and in vivo. These results suggest that the combination therapy using the inhibitors for both EGFR and PI3K/AKT/mTOR signaling pathways may be a novel therapeutic approach for HCC.

Gene expression of growth factors and growth factor receptors for potential targeted therapy of canine hepatocellular carcinoma

The purpose of this study was to evaluate the gene expression of growth factors and growth factor receptors of primary hepatic masses, including hepatocellular carcinoma (HCC) and nodular hyperplasia (NH), in dogs. Quantitative real-time reverse transcriptase-polymerase chain reaction was performed to measure the expression of 18 genes in 18 HCCs, 10 NHs, 11 surrounding non-cancerous liver tissues and 4 healthy control liver tissues. Platelet-derived growth factor-B (PDGF-B), transforming growth factor-α, epidermal growth factor receptor, epidermal growth factor and hepatocyte growth factor were found to be differentially expressed in HCC compared with NH and the surrounding non-cancerous and healthy control liver tissues. PDGF-B is suggested to have the potential to become a valuable ancillary target for the treatment of canine HCC.

An update on clinical trials in the treatment of advanced hepatocellular carcinoma

Despite the successful FDA approval of sorafenib as the standard of care therapy in patients with advanced hepatocellular carcinoma (HCC), its clinical benefits have been modest. The mortality rate remains high and prognosis poor for patients with advanced-stage HCC. The exact mechanism of sorafenib in the treatment of HCC and its resistance at the molecular levels are largely unknown. There are no other treatment options in first-line therapy and there is currently no standard of care second-line therapies available. Thus, there is a critical need for novel therapeutic approaches for the treatment of advanced HCC, and thus a clear justification for the already reported, currently ongoing, and planned clinical trials.

Hepatitis B Virus-Encoded X Protein Downregulates EGFR Expression via Inducing MicroRNA-7 in Hepatocellular Carcinoma Cells

Hepatitis B virus (HBV) infection accounts for over a half of cases of hepatocellular carcinoma (HCC), the most frequent malignant tumor of the liver. HBV-encoded X (HBx) plays critical roles in HBV-associated hepatocarcinogenesis. However, it is unclear whether and how HBx regulates the expression of epidermal growth factor receptor (EGFR), an important gene for cell growth. Therefore, the study aimed to investigate the association between HBx and EGFR expression. In this study, we found that HBx upregulates miR-7 expression to target 3′UTR of EGFR mRNA, which in turn results in the reduction of EGFR protein expression in HCC cells. HBx-mediated EGFR suppression renders HCC cells a slow-growth behavior. Deprivation of HBx or miR-7 expression or restoration of EGFR expression can increase the growth rate of HCC cells. Our data showed the miR-7-dependent EGFR suppression by HBx, supporting an inhibitory role of HBx in the cell growth of HCC. These findings not only identify miR-7 as a novel regulatory target of HBx, but also suggest HBx-miR-7-EGFR as a critical signaling in controlling the growth rate of HCC cells.

Molecular imaging of hepatocellular carcinoma xenografts with epidermal growth factor receptor targeted affibody probes

Hepatocellular carcinoma (HCC) is a highly aggressive and lethal cancer. It is typically asymptomatic at the early stage, with only 10%–20% of HCC patients being diagnosed early enough for appropriate surgical treatment. The delayed diagnosis of HCC is associated with limited treatment options and much lower survival rates. Therefore, the early and accurate detection of HCC is crucial to improve its currently dismal prognosis. The epidermal growth factor receptor (EGFR) has been reported to be involved in HCC tumorigenesis and to represent an attractive target for HCC imaging and therapy. In this study, an affibody molecule, Ac-Cys-Z_EGFR:1907, targeting the extracellular domain of EGFR, was used for the first time to assess its potential to detect HCC xenografts. By evaluating radio- or fluorescent-labeled Ac-Cys-Z_EGFR:1907 as a probe for positron emission tomography (PET) or optical imaging of HCC, subcutaneous EGFR-positive HCC xenografts were found to be successfully imaged by the PET probe. Thus, affibody-based PET imaging of EGFR provides a promising approach for detecting HCC in vivo.

The evolving landscape of therapeutic drug development for hepatocellular carcinoma

Currently, only one drug, sorafenib, is FDA approved for the treatment of advanced hepatocellular carcinoma (HCC), achieving modest objective response rates while still conferring an overall survival benefit. Unlike other solid tumors, no oncogenic addiction loops have been validated as clinically actionable targets in HCC. Outcomes of HCC could potentially be improved if critical molecular subclasses with distinct therapeutic vulnerabilities can be identified, biomarkers that predict recurrence or progression early can be determined and key epigenetic, genetic or microenvironment drivers that determine best response to a specific targeting treatment can be uncovered. Our group and others have examined the molecular heterogeneity of hepatocellular carcinoma. We have developed a panel of patient derived xenograft models to enable focused pre-clinical drug development of rationally designed therapies in specific molecular subgroups. We observed unique patterns, including synergies, of drug activity across our molecularly diverse HCC xenografts, pointing to specific therapeutic vulnerabilities for individual tumors. These efforts inform clinical trial designs and catalyze therapeutic development. It also argues for efficient strategic allocation of patients into appropriate enriched clinical trials. Here, we will discuss some of the recent important therapeutic studies in advanced HCC and also some of the potential strategies to optimize clinical therapeutic development moving forward.

New agents on the horizon in hepatocellular carcinoma

Despite the successful approval and extensive application of sorafenib, the prognosis for patients with advanced hepatocellular carcinoma (HCC) remains poor. Fortunately, there have been renewed and continued interests and active research in developing other molecularly targeted agents in HCC during the past few years. While there is early evidence of antitumor activity of several agents in phase I/II studies, phase III efforts with a few targeted agents have failed, highlighting the challenges of new drug development in HCC. This review summarizes the current status of other molecularly targeted agents under development in advanced HCC.

Inhibition of CIP2A determines erlotinib-induced apoptosis in hepatocellular carcinoma

Erlotinib is a small-molecular inhibitor of epidermal growth factor receptor (EGFR). Here, we identify that cancerous inhibitor of protein phosphatase 2A (CIP2A) is a major determinant mediating erlotinib-induced apoptosis in hepatocellular carcinoma (HCC). Erlotinib showed differential effects on apoptosis in 4 human HCC cell lines. Erlotinib induced significant apoptosis in Hep3B and PLC5 cell lines; however, Huh-7 and HA59T cell lines showed resistance to erlotinib-induced apoptosis at all tested doses. Down-regulation of CIP2A, a cellular inhibitor of protein phosphatase 2A (PP2A), mediated the apoptotic effect of erlotinib in HCC. Erlotinib inhibited CIP2A in a dose- and time-dependent manner in all sensitive HCC cells whereas no alterations in CIP2A were found in resistant cells. Overexpression of CIP2A upregulated phospho-Akt and protected Hep3B cells from erlotinib-induced apoptosis. In addition, silencing CIP2A by siRNA restored the effects of erlotinib in Huh-7 cells. Moreover, adding okadaic acid, a PP2A inhibitor, abolished the effects of erlotinib on apoptosis in Hep3B cells; and forskolin, a PP2A agonist enhanced the effect of erlotinib in resistant HA59T cells. Combining Akt inhibitor MK-2206 with erlotinib restored the sensitivity of HA59T cells to erlotinib. Furthermore, in vivo xenograft data showed that erlotinib inhibited the growth of PLC5 tumor but had no effect on Huh-7 tumor. Erlotinib downregulated CIP2A and upregulated PP2A activity in PLC5 tumors, but not in Huh-7 tumors. In conclusion, inhibition of CIP2A determines the effects of erlotinib on apoptosis in HCC. CIP2A may be useful as a therapeutic biomarker for predicting clinical response to erlotinib in HCC treatment.

Molecularly targeted therapy for advanced hepatocellular carcinoma in 2012: current status and future perspectives

Improving the overall survival for patients with advanced hepatocellular carcinoma (HCC) requires development of effective systemic therapy. Despite the successful approval and extensive application of sorafenib, the prognosis for patients with advanced HCC remains poor and the benefits with sorafenib are modest. In the past few years, there have been renewed and continued interests and active research in developing other molecularly targeted agents in HCC. While the initial efforts are focusing on anti-angiogenic therapy, other agents targeting the epidermal growth factor-receptor, mammalian target of rapamycin (mTOR), hepatocyte growth factor/c-Met among others have entered HCC clinical trials. Combining different molecularly targeted agents or combining targeted agents with chemotherapy represent other strategies under investigation. This review will attempt to summarize the current status of other molecularly targeted agents or regimens beyond sorafenib under development in advanced HCC and the future perspectives.

Systemic treatment and targeted therapy in patients with advanced hepatocellular carcinoma

BACKGROUND

ADVANCED HEPATOCELLULAR CARCINOMA (HCC) IS A MALIGNANCY OF GLOBAL IMPORTANCE: it is the sixth most common cancer and the third most common cause of cancer-related mortality worldwide. Despite decades of efforts by many investigators, systemic chemotherapy or hormone therapy has failed to demonstrate improved survival in patients with HCC.. Ongoing studies are evaluating the efficacy and tolerability of combining Sorafenib with erlotinib and other targeted agents or chemotherapy.

AIMS

On the basis of placebo-controlled, randomized phase III trials, Sorafenib has shown improved survival benefits in advanced HCC and has set a new standard for future clinical trials. The successful clinical development of Sorafenib in HCC has ushered in the era of molecularly targeted agents in this disease, which is discussed in this educational review.

MATERIAL AND METHODS

Many molecularly targeted agents that inhibit angiogenesis, epidermal growth factor receptor, and mammalian target of rapamycin are at different stages of clinical development in advanced HCC. Future research should continue to unravel the mechanism of hepatocarcinogenesis and to identify key relevant molecular targets for therapeutic intervention. Identification and validation of potential surrogate and predictive biomarkers hold promise to individualize patients' treatment to maximize clinical benefit and minimize the toxicity and cost of targeted agents.

RESULTS

Systemic therapy with various classes of agents, including hormone and cytotoxic agents, has provided no or marginal benefits. Improved understanding of the mechanism of hepatocarcinogenesis, coupled with the arrival of many newly developed molecularly targeted agents, has provided the unique opportunity to study some of these novel agents in advanced HCC.

CONCLUSIONS

The demonstration of improved survival benefits by Sorafenib in advanced HCC has ushered in the era of molecular-targeted therapy in this disease, with many agents undergoing active clinical development.

Targeted therapy for hepatocellular carcinoma: novel agents on the horizon

Hepatocellular carcinoma (HCC) is the most common liver cancer, accounting for 90% of primary liver cancers. In the last decade it has become one of the most frequently occurring tumors worldwide and is also considered to be the most lethal of the cancer systems, accounting for approximately one third of all malignancies. Although the clinical diagnosis and management of early-stage HCC has improved significantly, HCC prognosis is still extremely poor. Furthermore, advanced HCC is a highly aggressive tumor with a poor or no response to common therapies. Therefore, new effective and well-tolerated therapy strategies are urgently needed. Targeted therapies have entered the field of anti-neoplastic treatment and are being used on their own or in combination with conventional chemotherapy drugs. Molecular-targeted therapy holds great promise in the treatment of HCC. A new therapeutic opportunity for advanced HCC is the use of sorafenib (Nexavar). On the basis of the recent large randomized phase III study, the Sorafenib HCC Assessment Randomized Protocol (SHARP), sorafenib has been approved by the FDA for the treatment of advanced HCC. Sorafenib showed to be able to significantly increase survival in patients with advanced HCC, establishing a new standard of care. Despite this promising breakthrough, patients with HCC still have a dismal prognosis, as it is currently the major cause of death in cirrhotic patients. Nevertheless, the successful results of the SHARP trial underscore the need for a comprehensive understanding of the molecular pathogenesis of this devastating disease. In this review we summarize the most important studies on the signaling pathways implicated in the pathogenesis of HCC, as well as the newest emerging drugs and their potential use in HCC management.

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

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

Epidermal Growth Factor Receptor (EGFR) Crosstalks in Liver Cancer

Hepatocarcinogenesis is a complex multistep process in which many different molecular pathways have been implicated. Hepatocellular carcinoma (HCC) is refractory to conventional chemotherapeutic agents, and the new targeted therapies are meeting with limited success. Interreceptor crosstalk and the positive feedback between different signaling systems are emerging as mechanisms of targeted therapy resistance. The identification of such interactions is therefore of particular relevance to improve therapeutic efficacy. Among the different signaling pathways activated in hepatocarcinogenesis the epidermal growth factor receptor (EGFR) system plays a prominent role, being recognized as a “signaling hub” where different extracellular growth and survival signals converge. EGFR can be transactivated in response to multiple heterologous ligands through the physical interaction with multiple receptors, the activity of intracellular kinases or the shedding of EGFR-ligands. In this article we review the crosstalk between the EGFR and other signaling pathways that could be relevant to liver cancer development and treatment.

Growth suppression of human hepatocellular carcinoma xenografts by a monoclonal antibody CH12 directed to epidermal growth factor receptor variant III

Human hepatocellular carcinoma (HCC) is considered difficult to cure because it is resistant to radio- and chemotherapy and has a high recurrence rate after curative liver resection. Epidermal growth factor receptor variant III (EGFRvIII) has been reported to express in HCC tissues and cell lines. This article describes the efficacy of an anti-EGFRvIII monoclonal antibody (mAb CH12) in the treatment of HCC xenografts with EGFRvIII expression and the underlying mechanism of EGFRvIII as an oncogene in HCC. The results demonstrated that CH12 bound preferentially to EGFRvIII with a dissociation constant (K(d)) of 1.346 nm/liter. In addition, CH12 induces strong antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in Huh7-EGFRvIII (with exogenous expression of EGFRvIII) and SMMC-7721 (with endogenous expression of EGFRvIII) cells. Notably, CH12 significantly inhibited the growth of Huh7-EGFRvIII and SMMC-7721 xenografts in vivo with a growth inhibition ratio much higher than C225, a U. S. Food and Drug Administration-approved anti-EGFR antibody. Treatment of the two HCC xenografts with CH12 significantly suppressed tumor proliferation and angiogenesis. Mechanistically, in vivo treatment with CH12 reduced the phosphorylation of constitutively active EGFRvIII, Akt, and ERK. Down-regulation of the apoptotic protectors Bcl-x(L), Bcl-2, and the cell cycle regulator cyclin D1, as well as up-regulation of the cell-cycle inhibitor p27, were also observed after in vivo CH12 treatment. Collectively, these results indicate that the monoclonal antibody CH12 is a promising therapeutic agent for HCC with EGFRvIII expression.

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.

Beyond sorafenib: novel targeted therapies for advanced hepatocellular carcinoma

IMPORTANCE OF THE FIELD

The successful approval of sorafenib has greatly stimulated the development of other molecular targeted agents in advanced hepatocellular carcinoma (HCC).

AREAS COVERED IN THIS REVIEW

The aim of this review was to summarize the key data of sorafenib Phase III studies and the lessons and unanswered questions with sorafenib in HCC. It extensively updated the current ongoing studies combining sorafenib with erlotinib and other targeted agents or chemotherapy, and many molecularly targeted agents under development that inhibit angiogenesis, EGFR, and mammalian target of rapamycin (mTOR).

WHAT THE READER WILL GAIN

A comprehensive understanding of the current status of drug development of targeted agents in advanced HCC and insights into the challenges of developing these agents in HCC.

TAKE HOME MESSAGE

Sorafenib is the first and only approved agent in advanced HCC. Several Phase III studies are ongoing with other drugs in advanced HCC. Many early clinical trials are conducted to assess other molecularly targeted agents that inhibit different pathways of hepatocarcinogenesis.

Putative association of transforming growth factor-alpha polymorphisms with clearance of hepatitis B virus and occurrence of hepatocellular carcinoma in patients with chronic hepatitis B virus infection

Previous studies showed that several genetic polymorphisms might influence the clinical outcome of chronic hepatitis B virus (HBV) infection, including HBV clearance or development of hepatocellular carcinoma (HCC). The aim of this study was to determine whether polymorphisms of the transforming growth factor-alpha (TGF-alpha) gene are associated with clinical outcome of HBV infection. A total of 1096 Korean subjects having either present or past evidence of HBV infection were prospectively enrolled between January 2001 and August 2003. Among 16 genetic variants in TGFA gene, nine variants were genotyped using TaqMan assay and the genetic association with HBV clearance and HCC occurrence was analysed. Statistical analyses revealed that TGFA+103461T>C, TGFA+106151C>G and TGFA-ht2 were marginally associated with clearance of HBV infection. However, only TGFA-ht2 retained significance after multiple correction (OR = 0.39, P(corr) = 0.007 in recessive model). Although no variants were significant after multiple correction, TGFA+88344G>A and TGFA+103461T>C were weakly associated in recessive model in the analysis of HCC occurrence. In addition, Cox relative hazards model also revealed that TGFA+88344G>A was associated with onset age of HCC occurrence in subjects (RH = 1.46, P(corr) = 0.04). TGF-alpha polymorphisms might be an important factor in immunity, progression of inflammatory process and carcinogenesis, which explains the variable outcome of HBV infection at least in part. Further biological evidence is warranted in the future to support these suggestive associations.

Systemic treatment of hepatocellular carcinoma: dawn of a new era?

PURPOSE AND DESIGN

Despite decades of efforts by many investigators, systemic chemotherapy or hormone therapy have failed to demonstrate improved survival in patients with advanced hepatocellular carcinoma (HCC). On the basis of placebo-controlled, randomized phase III trials, sorafenib has shown improved survival benefits in advanced HCC and has set a new standard for future clinical trials. The successful clinical development of sorafenib in HCC has ushered in the era of molecularly targeted agents in this disease, which is discussed in this educational review.

RESULTS AND CONCLUSION

Ongoing studies are evaluating the efficacy and tolerability of combining sorafenib with erlotinib and other targeted agents or chemotherapy. Many molecularly targeted agents that inhibit angiogenesis, epidermal growth factor receptor, and mammalian target of rapamycin are at different stages of clinical development in advanced HCC. Combining targeted agents that inhibit different pathways in hepatocarcinogenesis is an area of active investigation. Future research should continue to unravel the mechanism of hepatocarcinogenesis and to identify key relevant molecular targets for therapeutic intervention. Identification and validation of potential surrogate and predictive biomarkers holds promise to individualize patients' treatment to maximize clinical benefit and minimize the toxicity and cost of targeted agents. We hope that we will continue to improve the efficacy of systemic therapy in advanced HCC in the coming years.

The disease relevance of human hepatocellular xenograft models: molecular characterization and review of the literature

In recent years a number of new therapeutics has been developed that were not general toxins and inhibitors of cell division like classical chemotherapeutics, but were designed to target a specific pathway. A prerequisite for this development was the comprehensive characterization of molecular alterations occurring in human hepatocellular carcinoma (HCC). However, while much knowledge of the molecular pathogenesis of human HCC has been gained, the model systems used to test the functional relevance of these alterations and applied for preclinical evaluation of drug candidates are still poorly characterized. In this paper, we reviewed the literature about several commonly used HCC cell lines and xenotransplantation models and present our own data on the molecular characterization of these. Results obtained demonstrate that it is important to have a sound knowledge of the specific molecular constitution of the experimental model and to carefully evaluate the functional status of the pathway of interest. For this reason, we make the gene expression profiles publicly available to help researchers making an informed decision about which model to use.

Ethanol-TGFalpha-MEK signaling promotes growth of human hepatocellular carcinoma

BACKGROUND

Chronic ethanol intake is a significant risk factor for the development of cirrhosis and hepatocellular carcinoma (HCC). The effects of ethanol on extracellular signal-regulated kinase (ERK) activation, transforming growth factor alpha (TGF-alpha), and HCC growth were examined in this study.

METHODS

HepG2, SKHep, Hep3B human HCC cells, or normal human hepatocytes were treated with ethanol (0-100 mM), exogenous TGF-alpha, TGF-alpha neutralization antibody or the MEK inhibitor U0126. TGF-alpha levels were quantified by ELISA. Growth was determined by trypan blue-excluded cell counts. Cell cycle phase distribution was determined by flow cytometry. Protein expression was determined by Western blot.

RESULTS

Ethanol treatment (10-40 mM) increased ERK activation in HepG2 and SKHep HCC cells but not in Hep3B or human hepatocyte cells. Growth increased in HepG2 (174 +/- 29%, P < 0.05) and SKHep (149 +/- 12%, P < 0.05) cells in response to ethanol treatment. Correspondingly, ethanol increased S phase distribution in these cells. U0126 suppressed ethanol-induced growth increases. Ethanol treatment for 24 h also raised TGF-alpha levels in HepG2 cells (118%-198%) and SKHep cells (112%-177%). Exogenous administration of recombinant TGF-alpha mimicked the ethanol-induced growth in HepG2 and SKHep cells; TGF-alpha neutralization antibody effectively abrogated this effect. The TGF-a neutralization antibody also prevented ERK activation by ethanol in HepG2 cells.

CONCLUSIONS

These data demonstrate that clinically relevant doses of ethanol stimulate ERK-dependent proliferation of HCC cells. Ethanol up-regulates TGF-alpha levels in HCC cells and enhances growth through cell cycles changes, which appear to be mediated through TGF-alpha-MEK-ERK signaling. Ethanol-MEK signaling in normal hepatocytes is absent, suggesting that ethanol promotion of HCC growth may in part depend upon the acquisition of cancer-specific signaling by hepatocytes.