First-in-man phase I study of GC33, a novel recombinant humanized antibody against glypican-3, in patients with advanced hepatocellular carcinoma

Humanization of high-affinity antibodies targeting glypican-3 in hepatocellular carcinoma

Glypican-3 (GPC3) is a cell-surface heparan sulfate proteoglycan highly expressed in hepatocellular carcinoma (HCC). We have generated a group of high-affinity mouse monoclonal antibodies targeting GPC3. Here, we report the humanization and testing of these antibodies for clinical development. We compared the affinity and cytotoxicity of recombinant immunotoxins containing mouse single-chain variable regions fused with a Pseudomonas toxin. To humanize the mouse Fvs, we grafted the combined KABAT/IMGT complementarity determining regions (CDR) into a human IgG germline framework. Interestingly, we found that the proline at position 41, a non-CDR residue in heavy chain variable regions (VH), is important for humanization of mouse antibodies. We also showed that two humanized anti-GPC3 antibodies (hYP7 and hYP9.1b) in the IgG format induced antibody-dependent cell-mediated cytotoxicity and complement-dependent-cytotoxicity in GPC3-positive cancer cells. The hYP7 antibody was tested and showed inhibition of HCC xenograft tumor growth in nude mice. This study successfully humanizes and validates high affinity anti-GPC3 antibodies and sets a foundation for future development of these antibodies in various clinical formats in the treatment of liver cancer.

Glypican-3 level assessed by the enzyme-linked immunosorbent assay is inferior to alpha-fetoprotein level for hepatocellular carcinoma diagnosis

Background/Aims

Glypican-3 (GPC3) protein is highly expressed in hepatocellular carcinoma (HCC) tissue. It has been suggested as a diagnostic biomarker, but its inconsistent performance means that it requires further assessment. We therefore investigated the diagnostic value of the plasma GPC3 level compared to the alpha-fetoprotein (AFP) level as a diagnostic biomarker of HCC.

Methods

We enrolled 157 consecutive patients with newly diagnosed HCC and 156 patients with liver cirrhosis (LC) as the control group. GPC3 plasma levels were measured using two commercially available enzyme-linked immunosorbent assays (ELISAs, named as Assay 1 and 2), and AFP levels were measured using an enzyme-linked chemiluminescent immunoassay. The diagnostic accuracy was analyzed using the receiver operating characteristics (ROC) curve.

Results

Plasma GPC3 levels in HCC patients were very low (0–3.09 ng/mL) in Assay 1, while only 3 of the 157 patients (1.9%) showed detectable GPC3 levels in Assay 2. The median GPC3 level was not significantly elevated in the HCC group (0.80 ng/mL) compared with the LC group (0.60 ng/mL). The area under the ROC curve (AUC) for GPC3 was 0.559 in Assay 1. In contrast, the median AFP level was significantly higher in HCC (27.72 ng/mL) than in LC (4.74 ng/mL), with an AUC of 0.729.

Conclusion

The plasma level of GPC3 is a poor diagnostic marker for HCC, being far inferior to AFP. The development of a consistent detection system for the blood level of GPC3 is warranted.

Aptamers against Cells Overexpressing Glypican 3 from Expanded Genetic Systems Combined with Cell Engineering and Laboratory Evolution

Laboratory in vitro evolution (LIVE) might deliver DNA aptamers that bind proteins expressed on the surface of cells. In this work, we used cell engineering to place glypican 3 (GPC3), a possible marker for liver cancer theranostics, on the surface of a liver cell line. Libraries were then built from a six-letter genetic alphabet containing the standard nucleobases and two added nucleobases (2-amino-8H-imidazo[1,2-a][1,3,5]triazin-4-one and 6-amino-5-nitropyridin-2-one), Watson-Crick complements from an artificially expanded genetic information system (AEGIS). With counterselection against non-engineered cells, eight AEGIS-containing aptamers were recovered. Five bound selectively to GPC3-overexpressing cells. This selection-counterselection scheme had acceptable statistics, notwithstanding the possibility that cells engineered to overexpress GPC3 might also express different off-target proteins. This is the first example of such a combination.

Redirecting T Cells to Glypican-3 with 4-1BB Zeta Chimeric Antigen Receptors Results in Th1 Polarization and Potent Antitumor Activity

T cells engineered to express CD19-specific chimeric antigen receptors (CARs) have shown breakthrough clinical successes in patients with B-cell lymphoid malignancies. However, similar therapeutic efficacy of CAR T cells in solid tumors is yet to be achieved. In this study we systematically evaluated a series of CAR constructs targeting glypican-3 (GPC3), which is selectively expressed on several solid tumors. We compared GPC3-specific CARs that encoded CD3ζ (Gz) alone or with costimulatory domains derived from CD28 (G28z), 4-1BB (GBBz), or CD28 and 4-1BB (G28BBz). All GPC3-CARs rendered T cells highly cytotoxic to GPC3-positive hepatocellular carcinoma, hepatoblastoma, and malignant rhabdoid tumor cell lines in vitro. GBBz induced the preferential production of Th1 cytokines (interferon γ/granulocyte macrophage colony-stimulating factor) while G28z preferentially induced Th2 cytokines (interleukin-4/interleukin-10). Inclusion of 4-1BB in G28BBz could only partially ameliorate the Th2-polarizing effect of CD28. 4-1BB induced superior expansion of CAR T cells in vitro and in vivo. T cells expressing GPC3-CARs incorporating CD28, 4-1BB, or both induced sustained tumor regressions in two xenogeneic tumor models. Thus, GBBz CAR endows T cells with superior proliferative potential, potent antitumor activity, and a Th1-biased cytokine profile, justifying further clinical development of GBBz CAR for immunotherapy of GPC3-positive solid tumors.

Hydrogen peroxide inducible clone-5 mediates reactive oxygen species signaling for hepatocellular carcinoma progression

One of the signaling components involved in hepatocellular carcinoma (HCC) progression is the focal adhesion adaptor paxillin. Hydrogen peroxide inducible clone-5 (Hic-5), one of the paralogs of paxillin, exhibits many biological functions distinct from paxillin, but may cooperate with paxillin to trigger tumor progression. Screening of Hic-5 in 145 surgical HCCs demonstrated overexpression of Hic-5 correlated well with intra- and extra-hepatic metastasis. Hic-5 highly expressed in the patient derived HCCs with high motility such as HCC329 and HCC353 but not in the HCCs with low motility such as HCC340. Blockade of Hic-5 expression prevented constitutive migration of HCC329 and HCC353 and HGF-induced cell migration of HCC340. HCC329Hic-5(−), HCC353Hic-5(−), HCC372Hic-5(−), the HCCs stably depleted of Hic-5, exhibited reduced motility compared with each HCC expressing Scramble shRNA. Moreover, intra/extrahepatic metastasis of HCC329Hic-5(−) in SCID mice greatly decreased compared with HCC329Scramble. On the other hand, ectopic Hic-5 expression in HCC340 promoted its progression. Constitutive and HGF-induced Hic-5 expression in HCCs were suppressed by the reactive oxygen species (ROS) scavengers catalase and dithiotheritol and c-Jun N-terminal kinase (JNK) inhibitor SP600125. On the contrary, depletion of Hic-5 blocked constitutive and HGF-induced ROS generation and JNK phosphorylation in HCCs. Also, ectopic expression of Hic-5 enhanced ROS generation and JNK phosphorylation. These highlighted that Hic-5 plays a central role in the positive feedback ROS-JNK signal cascade. Finally, the Chinese herbal derived anti-HCC peptide LZ-8 suppressed constitutive Hic-5 expression and JNK phosphorylation. In conclusion, Hic-5 mediates ROS-JNK signaling and may serve as a therapeutic target for prevention of HCC progression.

Randomized phase II placebo controlled study of codrituzumab in previously treated patients with advanced hepatocellular carcinoma

BACKGROUND & AIMS

Codrituzumab, a humanized monoclonal antibody against Glypican-3 (GPC3) that is expressed in hepatocellular carcinoma (HCC), interacts with CD16/FcγRIIIa and triggers antibody-dependent cytotoxicity. Codrituzumab was studied vs. placebo in a randomized phase II trial in advanced HCC patients who had failed prior systemic therapy.

METHODS

Patients with advanced HCC who had failed prior systemic therapy, ⩾18years, Eastern cooperative oncology group (ECOG) 0-1, Child-Pugh A were randomized 2:1 to biweekly codrituzumab 1600mg vs. placebo. Patients were stratified based on GPC3 immunohistochemical expression: 2+/3+, 1+, and 0. Primary endpoint was progression free survival. Secondary endpoints include overall survival (OS), tolerability, pharmacokinetics, and an exploratory endpoint in biomarkers analysis.

RESULTS

185 patients were enrolled: 125 received codrituzumab and 60 placebo: Median age 64/63, 85/75% male, 46/42% Asian, ECOG 0 65/63%, 74/77% having vascular invasion and/or extra-hepatic metastasis. 84%/70% had prior sorafenib. Drug exposure was 98.4% of planned dose, with an identical adverse events profile between the 2 groups. The median progression free survival and overall survival in the codrituzumab vs. placebo groups in months were: 2.6 vs. 1.5 (hazard ratios 0.97, p=0.87), and 8.7 vs. 10 (hazard ratios 0.96, p=0.82). Projected Ctrough at cycle 3day 1 based exposure, high CD16/FcγRIIIa on peripheral immune cells, and GPC3 expression in the tumor, were all associated with prolonged progression free survival and overall survival.

CONCLUSIONS

Codrituzumab did not show clinical benefit in this previously treated HCC population. Whether higher codrituzumab drug exposure or the use of CD16 and GPC3 as potential biomarkers would improve outcome remain unanswered questions.

LAY SUMMARY

Codrituzumab is a manufactured antibody against a liver cancer protein called glypican-3. In this clinical trial, codrituzumab was not found be effective against liver cancer. It was suggested though that a higher dose of codrituzumab or selecting patients with high level of glypican-3 or its mediator CD16 might improve outcome.

CLINICAL TRIAL REGISTRATION

This trial is registered at Clinicaltrials.gov (NCT01507168).

Personalized Clinical Trials in Hepatocellular Carcinoma Based on Biomarker Selection

BACKGROUND

Since the approval of sorafenib there have been numerous failures of new agents in Phase III studies for treatment of advanced hepatocellular carcinoma (HCC). These studies have generally ignored the molecular heterogeneity of HCC and they have not enrolled patients based on predictive markers of response. The development of molecular targeted therapeutics in HCC needs to model the approach that has been taken with great success in other solid tumors, to decrease the likelihood of failure in future studies.

SUMMARY

Here we review the paradigm taken with novel targeted agents in other solid tumors and highlight ongoing studies in HCC that are incorporating biomarkers in clinical development.

KEY MESSAGES

With the appreciation of the molecular diversity of HCC, clinical development of new agents in HCC will need to be targeted towards those patients who are most likely to benefit. This strategy, based on biomarkers for patient selection, is more likely to yield positive results and mitigate the risk of continued negative Phase III studies.

Hepatic macrophages in homeostasis and liver diseases: from pathogenesis to novel therapeutic strategies

Macrophages represent a major cell type of innate immunity and have emerged as a critical player and therapeutic target in many chronic inflammatory diseases. Hepatic macrophages consist of Kupffer cells, which are originated from the fetal yolk-sack, and infiltrated bone marrow-derived monocytes/macrophages. Hepatic macrophages play a central role in maintaining homeostasis of the liver and in the pathogenesis of liver injury, making them an attractive therapeutic target for liver diseases. However, the various populations of hepatic macrophages display different phenotypes and exert distinct functions. Thus, more research is required to better understand these cells to guide the development of macrophage-based therapeutic interventions. This review article will summarize the current knowledge on the origins and composition of hepatic macrophages, their functions in maintaining hepatic homeostasis, and their involvement in both promoting and resolving liver inflammation, injury, and fibrosis. Finally, the current strategies being developed to target hepatic macrophages for the treatment of liver diseases will be reviewed.

Glypican-3 is a prognostic factor and an immunotherapeutic target in hepatocellular carcinoma

Glypican-3 (GPC3) is a cell surface oncofetal proteoglycan that is anchored by glycosylphosphatidylinositol. Whereas GPC3 is abundant in fetal liver, its expression is hardly detectable in adult liver. Importantly, GPC3 is overexpressed in hepatocellular carcinoma (HCC), and several immunohistochemical studies reported that overexpression predicts a poorer prognosis for HCC patients. Therefore, GPC3 would serve as a useful molecular marker for HCC diagnosis and also as a target for therapeutic intervention in HCC. Indeed, some immunotherapy protocols targeting GPC3 are under investigations; those include humanized anti-GPC3 cytotoxic antibody, peptide vaccine and immunotoxin therapies. When considering the clinical requirements for GPC3-targeting therapy, companion diagnostics to select the appropriate HCC patients are critical, and both immunohistochemical analysis of tissue sections and measurement of serum GPC3 level have been suggested for this purpose. This review summarizes current knowledge regarding the clinical implication of GPC3 detection and targeting in the management of patients with HCC.

Clinicopathological indices to predict hepatocellular carcinoma molecular classification

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is the second most lethal cancer caused by lack of effective therapies. Although promising, HCC molecular classification, which enriches potential responders to specific therapies, has not yet been assessed in clinical trials of anti-HCC drugs. We aimed to overcome these challenges by developing clinicopathological surrogate indices of HCC molecular classification.

METHODS

Hepatocellular carcinoma classification defined in our previous transcriptome meta-analysis (S1, S2 and S3 subclasses) was implemented in an FDA-approved diagnostic platform (Elements assay, NanoString). Ninety-six HCC tumours (training set) were assayed to develop molecular subclass-predictive indices based on clinicopathological features, which were independently validated in 99 HCC tumours (validation set). Molecular deregulations associated with the histopathological features were determined by pathway analysis. Sample sizes for HCC clinical trials enriched with specific molecular subclasses were determined.

RESULTS

Hepatocellular carcinoma subclass-predictive indices were steatohepatitic (SH)-HCC variant and immune cell infiltrate for S1 subclass, macrotrabecular/compact pattern, lack of pseudoglandular pattern, and high serum alpha-foetoprotein (>400 ng/ml) for S2 subclass, and microtrabecular pattern, lack of SH-HCC and clear cell variants, and lower histological grade for S3 subclass. Macrotrabecular/compact pattern, a predictor of S2 subclass, was associated with the activation of therapeutically targetable oncogene YAP and stemness markers EPCAM/KRT19. BMP4 was associated with pseudoglandular pattern. Subclass-predictive indices-based patient enrichment reduced clinical trial sample sizes from 121, 184 and 53 to 30, 43 and 22 for S1, S2 and S3 subclass-targeting therapies respectively.

CONCLUSIONS

Hepatocellular carcinoma molecular subclasses can be enriched by clinicopathological indices tightly associated with deregulation of therapeutically targetable molecular pathways.

Immunological landscape and immunotherapy of hepatocellular carcinoma

Advanced hepatocellular carcinoma (HCC) is a serious therapeutic challenge and targeted therapies only provide a modest benefit in terms of overall survival. Novel approaches are urgently needed for the treatment of this prevalent malignancy. Evidence demonstrating the antigenicity of tumour cells, the discovery that immune checkpoint molecules have an essential role in immune evasion of tumour cells, and the impressive clinical results achieved by blocking these inhibitory receptors, are revolutionizing cancer immunotherapy. Here, we review the data on HCC immunogenicity, the mechanisms for HCC immune subversion and the different immunotherapies that have been tested to treat HCC. Taking into account the multiplicity of hyperadditive immunosuppressive forces acting within the HCC microenvironment, a combinatorial approach is advised. Strategies include combinations of systemic immunomodulation and gene therapy, cell therapy or virotherapy.

Molecular classification of hepatocellular carcinoma: potential therapeutic implications

Genomic profiling of hepatocellular carcinoma (HCC) tumors has elucidated recurrent molecular aberrations common or specific to disease etiology, patient race or geographic regions, allowing the classification of HCC tumors into subclasses sharing similar molecular and clinical characteristics. Previously reported transcriptome-based molecular subclasses have highlighted several common themes. Aggressive tumors are characterized by TP53 inactivation mutations and activation of pro-oncogenic signaling pathways, and further subclassified according to expression of stemness markers. The stemness marker-negative aggressive tumors display preferential TGF-β activation. Another group of less aggressive tumors contains a subclass characterized by CTNNB1 mutations accompanied with overexpression of liver-specific WNT targets such as GLUL. Molecular therapies selectively targeting features of the HCC subclasses have suggested their utility in enriching potential responders in clinical trials and guiding therapeutic decision-making for HCC patients.

Biomarkers for the early diagnosis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the second leading cause of cancer-related deaths worldwide. Although the prognosis of patients with HCC is generally poor, the 5-year survival rate is > 70% if patients are diagnosed at an early stage. However, early diagnosis of HCC is complicated by the coexistence of inflammation and cirrhosis. Thus, novel biomarkers for the early diagnosis of HCC are required. Currently, the diagnosis of HCC without pathological correlation is achieved by analyzing serum α-fetoprotein levels combined with imaging techniques. Advances in genomics and proteomics platforms and biomarker assay techniques over the last decade have resulted in the identification of numerous novel biomarkers and have improved the diagnosis of HCC. The most promising biomarkers, such as glypican-3, osteopontin, Golgi protein-73 and nucleic acids including microRNAs, are most likely to become clinically validated in the near future. These biomarkers are not only useful for early diagnosis of HCC, but also provide insight into the mechanisms driving oncogenesis. In addition, such molecular insight creates the basis for the development of potentially more effective treatment strategies. In this article, we provide an overview of the biomarkers that are currently used for the early diagnosis of HCC.

T Cells Engineered to Express a T-Cell Receptor Specific for Glypican-3 to Recognize and Kill Hepatoma Cells In Vitro and in Mice

BACKGROUND & AIMS

Cancer therapies are being developed based on our ability to direct T cells against tumor antigens. Glypican-3 (GPC3) is expressed by 75% of all hepatocellular carcinomas (HCC), but not in healthy liver tissue or other organs. We aimed to generate T cells with GPC3-specific receptors that recognize HCC and used them to eliminate GPC3-expressing xenograft tumors grown from human HCC cells in mice.

METHODS

We used mass spectrometry to obtain a comprehensive peptidome from GPC3-expressing hepatoma cells after immune-affinity purification of human leukocyte antigen (HLA)-A2 and bioinformatics to identify immunodominant peptides. To circumvent GPC3 tolerance resulting from fetal expression, dendritic cells from HLA-A2-negative donors were cotransfected with GPC3 and HLA-A2 RNA to stimulate and expand antigen-specific T cells.

RESULTS

Peptide GPC3367 was identified as a predominant peptide on HLA-A2. We used A2-GPC3367 multimers to detect, select for, and clone GPC3-specific T cells. These clones bound the A2-GPC3367 multimer and secreted interferon-γ when cultured with GPC3367, but not with control peptide-loaded cells. By genomic sequencing of these T-cell clones, we identified a gene encoding a dominant T-cell receptor. The gene was cloned and the sequence was codon optimized and expressed from a retroviral vector. Primary CD8(+) T cells that expressed the transgenic T-cell receptor specifically bound GPC3367 on HLA-A2. These T cells killed GPC3-expressing hepatoma cells in culture and slowed growth of HCC xenograft tumors in mice.

CONCLUSIONS

We identified a GPC3367-specific T-cell receptor. Expression of this receptor by T cells allows them to recognize and kill GPC3-positive hepatoma cells. This finding could be used to advance development of adoptive T-cell therapy for HCC.

A Surgical Perspective on Targeted Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the second leading cause of cancer deaths worldwide, is difficult to treat and highly lethal. Since HCC is predominantly diagnosed in patients with cirrhosis, treatment planning must consider both the severity of liver disease and tumor burden. To minimize the impact to the patient while treating the tumor, techniques have been developed to target HCC. Anatomical targeting by surgical resection or locoregional therapies is generally reserved for patients with preserved liver function and minimal to moderate tumor burden. Patients with decompensated cirrhosis and small tumors are optimal candidates for liver transplantation, which offers the best chance of long-term survival. Yet, only 20%-30% of patients have disease amenable to anatomical targeting. For the majority of patients with advanced HCC, chemotherapy is used to target the tumor biology. Despite these treatment options, the five-year survival of patients in the United States with HCC is only 16%. In this review we provide a comprehensive overview of current approaches to target HCC. We also discuss emerging diagnostic and prognostic biomarkers, novel therapeutic targets identified by recent genomic profiling studies, and potential applications of immunotherapy in the treatment of HCC.

Potentiality of immunotherapy against hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, is the fifth most common cancer worldwide and the second leading cause of cancer-related death. Despite the high incidence, treatment options remain limited for advanced HCC, and as a result prognosis continues to be poor. Current therapeutic options, surgery, chemotherapy and radiotherapy, have only modest efficacy. New treatment modalities to prolong survival and to minimize the risk of adverse response are desperately needed for patients with advanced HCC. Tumor immunotherapy is a promising, novel treatment strategy that may lead to improvements in both treatment-associated toxicity and outcome. The strategies have developed in part through genomic studies that have yielded candidate target molecules and in part through basic biology studies that have defined the pathways and cell types regulating immune response. Here, we summarize the various types of HCC immunotherapy and argue that the newfound field of HCC immunotherapy might provide critical advantages in the effort to improve prognosis of patients with advanced HCC. Already several immunotherapies, such as tumor-associated antigen therapy, immune checkpoint inhibitors and cell transfer immunotherapy, have demonstrated safety and feasibility in HCC patients. Unfortunately, immunotherapy currently has low efficacy in advanced stage HCC patients; overcoming this challenge will place immunotherapy at the forefront of HCC treatment, possibly in the near future.

Antibody-based immunotherapy of solid cancers: progress and possibilities

Monoclonal antibodies remain a primary product option for novel cancer treatment. The properties of an antibody are a function of the antigen specificity and constant region incorporated. The rapid advance in molecular understanding of cancer biology and the host-tumor interaction has defined a new range of targets for antibody development. The clinical success of the checkpoint inhibitors has validated immune modulation and mobilization as a therapeutic approach. Solid cancers are distinguished from hematologic malignancies because the solid tumor stroma contains significant tumor promoting and immune dampening elements less prominent in hematologic cancer. This review highlights how engineered monoclonal antibody products are emerging as potential cornerstones of new more personalized cancer treatment paradigms that target both tumor and the stromal environment.

Hepatocellular carcinoma treatment over sorafenib: epigenetics, microRNAs and microenvironment. Is there a light at the end of the tunnel?

INTRODUCTION

Sorafenib is currently the only approved therapy in hepatocellular carcinoma (HCC). Alternative first- and second-line treatments are a significant unmet medical need, and several biologic agents have been tested in recent years, with poor results. Therefore, angiogenic pathways and the cytokine cascade remain possible targets in HCC. Recent studies suggest a role of epigenetic processes, associated with the initiation and development of HCC. In this field, DNA methylation, micro-RNAs (miRNAs) and tumor microenvironment cells became a possible new target for HCC treatment.

AREAS COVERED

This review explains the possible role of DNA methylation and histone deacetylase inhibitors as predictive biomarkers and target therapy, the extensive world of the promising miRNA blockade strategy, and the recent strong evidence of correlation between HCC tumors and peritumoral stroma cells. The literature and preclinic/clinic data were obtained through an electronic search.

EXPERT OPINION

Future research should aim to understand how best to identify patient groups that would benefit most from the prescribed therapy. To overcome the 'therapeutic stranding' of HCC, a possible way out from the current therapeutic tunnel might be to evaluate the major epigenetic and genetic processes involved in HCC carcinogenesis, not underestimating the tumor microenvironment and its 'actors' (angiogenesis, immune system, platelets). We are only at the start of a long journey towards the elucidation of HCC molecular pathways as therapeutic targets. Yet, currently this path appears to be the only one to cast some light at the end of the tunnel.

Enhanced specific antitumor immunity of dendritic cells transduced with the glypican 3 gene and co-cultured with cytokine-induced killer cells against hepatocellular carcinoma cells

Dendritic cell (DC)‑based cancer immunotherapy requires an immunogenic tumor‑associated antigen and an effective therapeutic strategy. Glypican 3 (GPC3) is a valuable diagnostic marker and a potential therapeutic target in hepatocellular carcinoma (HCC). The present study investigated whether DCs transduced with the GPC3 gene (DCs‑GPC3) and co‑cultured with autologous cytokine‑induced killer cells (CIKs) may induce a marked specific immune response against GPC3‑expressing HCC cells in vitro and in vivo. Human DCs were transfected with a green fluorescent protein plasmid with GPC3 by nucleofection and then co‑cultured with autologous CIKs. Flow cytometry was used to measure the phenotypes of DCs and CIKs. The co‑cultured cells were harvested and incubated with HCC cells and the cytotoxicity of the CIKs was assessed by nonradioactive cytotoxicity assay. The anti-tumor activity of these effector cells was further evaluated using a nude mouse tumor model. The results demonstrated that DCs‑GPC3 significantly promoted the autologous CIKs differentiation, as well as anti‑tumor cytokine interferon‑γ secretion. In addition, DCs‑GPC3‑CIKs significantly enhanced the cytotoxic activity against GPC3‑expressing HepG2 cells, indicating a GPC3‑specific marked immune response against HCC cells. The in vivo data indicated that DCs‑GPC3‑CIKs exhibited significant HepG2 cell‑induced tumor growth inhibition in nude mice. The results of the present study provided a new insight into the design of personalizing adoptive immunotherapy for GPC3‑expressing HCC cells.

Engineering α-fetoprotein-based gene vaccines to prevent and treat hepatocellular carcinoma: review and future prospects

Activation of a patient's immune system offers an attractive approach to prevent and treat hepatocellular carcinoma (HCC). However, the antitumor efficacy of current HCC vaccines was weak owing to insufficient immune activation of targeting self/tumor antigens. We recently found that epitope-optimized α-fetoprotein effectively activated CD8 T cells and generated potent antitumor effects in the carcinogen-induced autochthonous HCC mouse model. We predict that the same antigen engineering approach of epitope-optimization will enable us to develop effective human vaccines to prevent HCC recurrence after liver resection. The engineered human HCC vaccines may also allow us to identify high-affinity T-cell receptors and antibodies that can be used to reprogram T cells to treat HCC tumors via adoptive transfer.

Suppression of postsurgical recurrence of hepatocellular carcinoma treated with autologous formalin-fixed tumor vaccine, with special reference to glypican-3

Autologous formalin-fixed tumor vaccine (AFTV) suppressed re-recurrence for more than 32 months of multiple-recurrent hepatocellular carcinoma based on hepatitis C virus-induced liver cirrhosis in a case with previous recurrence interval, 51-, 28-, 12-, and 4-months. We detected glypican-3-specific cytotoxic T lymphocytes in the peripheral blood at 12 months after AFTV.

High preoperative levels of serum glypican-3 containing N-terminal subunit are associated with poor prognosis in patients with hepatocellular carcinoma after partial hepatectomy

Glypican-3 (GPC3) is a glycosylphosphatidylinositol-anchored cell surface glycoprotein overexpressed in hepatocellular carcinoma (HCC) cells and may serve as a potential molecular target for therapeutic intervention. This study evaluated the prognostic significance of serum GPC3 in HCC patients receiving curative surgery. A novel sandwich enzyme-linked immunosorbent assay for the quantitative and sensitive determination of serum GPC3 N-terminal subunit antigen (sGPC3N) was developed and used to measure sGPC3N levels in 25 healthy volunteers and 115 HCC patients who underwent curative partial hepatectomy. The relationships between sGPC3N and clinicopathologic features were analyzed and the prognostic impact on overall survival (OS) or disease-free survival (DFS) was also investigated. Mean and median levels of sGPC3N in healthy controls were 110.12 and 115.95 pg mL(-1) , respectively, with 185.52 pg mL(-1) (mean + 2 SD) being set as the upper limit of the normal range. In HCC patients, sGPC3N levels were significantly increased (mean/median, 405.16/236.19 pg mL(-1) ) compared to healthy controls (p < 0.0001), and 60% of HCC cases (69/115) showed sGPC3N levels that were higher than the upper normal limit. High sGPC3N levels were significantly associated with serum AFP level, high Child-Pugh score and positive HCV. Kaplan-Meier analysis indicated that elevated pre-operative sGPC3N was associated with shorter OS and DFS after hepatectomy (p ≤ 0.01). Multivariate analysis revealed elevated sGPC3N as an independent poor prognostic marker for OS (p < 0.05) and DFS (p < 0.01). The pre-operative sGPC3N level serves as an independent prognostic biomarker in HCC patients.

Targeting the tumor stroma in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and deadly cancers worldwide. In ninety percent of the cases it develops as a result of chronic liver damage and it is thus a typical inflammation-related cancer characterized by the close relation between the tumor microenvironment and tumor cells. The stromal environment consists out of several cell types, including hepatic stellate cells, macrophages and endothelial cells. They are not just active bystanders in the pathogenesis of HCC, but play an important and active role in tumor initiation, progression and metastasis. Furthermore, the tumor itself influences these cells to create a background that is beneficial for sustaining tumor growth. One of the key players is the hepatic stellate cell, which is activated during liver damage and differentiates towards a myofibroblast-like cell. Activated stellate cells are responsible for the deposition of extracellular matrix, increase the production of angiogenic factors and stimulate the recruitment of macrophages. The increase of angiogenic factors (which are secreted by macrophages, tumor cells and activated stellate cells) will induce the formation of new blood vessels, thereby supplying the tumor with more oxygen and nutrients, thus supporting tumor growth and offering a passageway in the circulatory system. In addition, the secretion of chemokines by the tumor cells leads to the recruitment of tumor associated macrophages. These tumor associated macrophages are key actors of cancer-related inflammation, being the main type of inflammatory cells infiltrating the tumor environment and exerting a tumor promoting effect by secreting growth factors, stimulating angiogenesis and influencing the activation of stellate cells. This complex interplay between the several cell types involved in liver cancer emphasizes the need for targeting the tumor stroma in HCC patients.

Preclinical trials for prevention of tumor progression of hepatocellular carcinoma by LZ-8 targeting c-Met dependent and independent pathways

Hepatocellular carcinoma (HCC) is among the most lethal cancers. Mounting studies highlighted the essential role of the HGF/c-MET axis in driving HCC tumor progression. Therefore, c-Met is a potential therapeutic target for HCC. However, several concerns remain unresolved in c-Met targeting. First, the status of active c-Met in HCC must be screened to determine patients suitable for therapy. Second, resistance and side effects have been observed frequently when using conventional c-Met inhibitors. Thus, a preclinical system for screening the status of c-Met signaling and identifying efficient and safe anti-HCC agents is urgently required. In this study, immunohistochemical staining of phosphorylated c-Met (Tyr1234) on tissue sections indicated that HCCs with positive c-Met signaling accounted for approximately 46% in 26 cases. Second, many patient-derived HCC cell lines were established and characterized according to motility and c-Met signaling status. Moreover, LZ8, a medicinal peptide purified from the herb Lingzhi, featuring immunomodulatory and anticancer properties, was capable of suppressing cell migration and slightly reducing the survival rate of both c-Met positive and negative HCCs, HCC372, and HCC329, respectively. LZ8 also suppressed the intrahepatic metastasis of HCC329 in SCID mice. On the molecular level, LZ8 suppressed the expression of c-Met and phosphorylation of c-Met, ERK and AKT in HCC372, and suppressed the phosphorylation of JNK, ERK, and AKT in HCC329. According to receptor array screening, the major receptor tyrosine kinase activated in HCC329 was found to be the epidermal growth factor receptor (EGFR). Moreover, tyrosine-phosphorylated EGFR (the active EGFR) was greatly suppressed in HCC329 by LZ8 treatment. In addition, LZ8 blocked HGF-induced cell migration and c-Met-dependent signaling in HepG2. In summary, we designed a preclinical trial using LZ8 to prevent the tumor progression of patient-derived HCCs with c-Met-positive or -negative signaling.

Systemic treatment of advanced hepatocellular carcinoma: from disillusions to new horizons

Hepatocellular carcinoma (HCC) is an aggressive malignancy, which accounts for a third of all cancer deaths globally each year. The management of patients with HCC is complex, as both the tumour stage and any underlying liver disease must be considered conjointly. Since the approval of sorafenib in advanced HCC, several phase III clinical trials have failed to demonstrate any superiority over sorafenib in the frontline setting, and no agent has been shown to impact outcomes after sorafenib failure. This review will focus on the range of experimental therapeutics for patients with advanced HCC and highlight the successes and failures of these treatments as well as areas for future development. Specifics such as dose limiting toxicity and safety profile in patients with liver dysfunction related to the underlying chronic liver disease should be considered when developing therapies in HCC. Finally, robust validated and reproducible surrogate end-points as well as predictive biomarkers should be defined in future randomised trials.

Immunotherapy of hepatocellular carcinoma

Newer immunotherapy agents may break the barrier that tumors create to evade the attack from the immune system. Dendritic cell vaccination has shown encouraging clinical activity and a favorable safety profile in advanced tumor stages. However, optimal cell maturation status, choice of tumor antigens and route of administration have not been established. Single or multiple peptides derived from tumor-associated antigens may also be used for cancer vaccination. Intratumoral delivery of oncolytic viruses expressing immunostimulating cytokines like GM-CSF have produced stimulating clinical results that need further verification. But it is probably T-cell checkpoint modulation with monoclonal antibodies that has attracted the highest expectations. Promising activity has been reported for tremelimumab, a CTLA-4 inhibitor, and a clinical trial testing the PD-1 antibody nivolumab is underway. Future progress will probably come from a better understanding of the mechanisms of cancer-related immunosuppression, improvement in agents and strategies and combination of the available therapeutic tools.

Glypican-3-targeting F(ab')2 for 89Zr PET of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an increasingly lethal malignancy for which management is critically dependent on accurate imaging. Glypican-3 (GPC3) is a cell surface receptor overexpressed in most HCCs and provides a unique target for molecular diagnostics. The use of monoclonal antibodies (mAbs) that target GPC3 (αGPC3) in PET imaging has shown promise but comes with inherent limitations associated with mAbs such as long circulation times. This study used (89)Zr-conjugated F(ab')2 fragments directed against GPC3 ((89)Zr-αGPC3-F(ab')2) to evaluate the feasibility of the fragments as a diagnostic immuno-PET imaging probe.

METHODS

Immobilized ficin was used to digest αGPC3, creating αGPC3-F(ab')2 fragments subsequently conjugated to (89)Zr. In vivo biodistribution and PET studies were performed on GPC3-expressing HepG2 and GPC3-nonexpressing RH7777 orthotopic xenografts.

RESULTS

Reliable αGPC3-F(ab')2 production via immobilized ficin digestion was verified by high-performance liquid chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. (89)Zr-αGPC3-F(ab')2 demonstrated F(ab')2-dependent, antigen-specific cell binding. HepG2 tumor uptake was higher than any other tissue, peaking at 100 ± 21 percentage injected dose per gram (%ID/g) 24 h after injection, a value 33- to 38-fold higher than GPC3-nonexpressing RH7777 tumors. The blood half-life of the (89)Zr-αGPC3-F(ab')2 conjugate was approximately 11 h, compared with approximately 115 h for historic mAb controls. This shorter half-life enabled clear tumor visualization on PET 4 h after administration, with a resultant peak tumor-to-liver contrast ratio of 23.3. Blocking antigen-expressing tumors with an excess of nonradiolabeled αGPC3 resulted in decreased tumor uptake similar to native liver. The kidneys exhibited high tissue uptake, peaking at 24 h with 83 ± 12 %ID/g. HepG2 tumors ranging from 1.5 to 7 mm were clearly visible on PET, whereas larger RH7777 tumors displayed signal lower than background liver tissue.

CONCLUSION

This study demonstrates the feasibility of using (89)Zr-αGPC3-F(ab')2 for intrahepatic tumor localization with small-animal PET. Faster blood clearance and lower background liver uptake enable excellent signal-to-noise ratios at early time points. Increased renal uptake is similar to that as has been seen with clinical radioactive peptide imaging. (89)Zr-αGPC3-F(ab')2 addresses some of the shortcomings of whole-antibody immuno-PET probes. Further optimization is warranted to maximize probe sensitivity and specificity in the process of clinical translation.

Glypican 3 overexpression in primary and metastatic Wilms tumors

Glypican 3 (GPC3), a heparan sulfate proteoglycan, plays a role in cell growth and differentiation. Mutations of the GPC3 gene are responsible for Simpson-Golabi-Behmel syndrome, which is characterized by anomalies of postnatal overgrowth and an increased risk of developing pediatric malignancies, mostly Wilms tumor and liver cancer. In order to understand the possible role of GPC3 in renal development and Wilms tumor formation, we analyzed messenger RNA (mRNA) and protein levels of GPC3 in sporadic Wilms tumors and compared it to normal kidneys and other common renal epithelial tumors. By using Affymetrix HGU133 oligonucleotide gene expression microarray data from 191 renal tumors and 12 normal kidneys, we found significant overexpression of GPC3 in Wilms tumors (p < 0.01), with 3.5-fold higher expression in comparison to normal kidneys and 6.5-fold higher than any type of renal tumors. The GPC3 gene product in Wilms tumor was further evaluated by immunohistochemistry and quantified by an automated image analysis. Cytoplasmic and membranous GPC3 immunoreactivity was present in 77 % of primary Wilms tumors (23/30), 93 % of metastatic Wilms tumors (13/14), 50 % of metanephric adenomas (4/8), 33 % of congenital mesoblastic nephromas (2/6), 100 % of nephrogenic rests (11/11), and 100 % of fetal kidneys (5/5). GPC3 staining was predominantly identified in blastemal and epithelial components of Wilms tumors, similar to that of fetal non-neoplastic kidney. All adult renal tumors (n = 60) and normal kidneys (n = 15) were GPC3 negative. These findings suggest the utility of GPC3 in differential diagnosis and follow-up of Wilms tumors. Our data also indicate that GPC3 is an oncofetal protein with a potential therapeutic value.

Discovery and diagnostic value of a novel oncofetal protein: glypican 3

Glypican 3 is a membrane-bound heparan sulfate proteoglycan, which has recently been identified as a marker for liver cancer and germ cell malignancies. Individuals with loss-of-function mutations for the glypican 3 gene exhibit Simpson-Golabi-Behmel syndrome, a rare X-linked overgrowth disorder. Expression of glypican 3 mRNA and protein is normally silenced in most adult organs and may reappear during malignant transformation. In the past few years, immunohistochemical and molecular characteristics of glypican 3 in hepatocellular carcinoma have been elucidated. More recently, glypican 3 has been emerging as a new diagnostic marker for germ cell tumors and especially testicular and ovarian yolk sac tumors. However, in other tumors such as renal cell carcinomas, squamous cell carcinomas, and melanomas, studies disagree on the level of glypican 3 expression. Finally, there is the controversial notion of glypican 3 as a tumor suppressor gene. In this review article, we update current knowledge on glypican 3 expression in normal and neoplastic tissues, evaluate its utility as a tumor marker in clinical practice, and explore its role as a novel oncofetal protein with clinical implications. Our focus is on the diagnostic value of glypican 3 in germ cell tumors and other neoplasms in addition to hepatocellular carcinoma. In conclusion, glypican 3 has been proven to be a useful immunohistochemical marker in distinguishing yolk sac tumors, choriocarcinomas, and Wilms tumors from other malignancies histologically mimicking these primitive tumors. Clinically, we recommend that glypican 3 be used as part of a panel of markers in subtyping testicular germ cell tumors.

Development of T cells redirected to glypican-3 for the treatment of hepatocellular carcinoma

PURPOSE

The aim of our study is to elucidate whether T cells expressing GPC3-targeted chimeric antigen receptor (CAR) can efficiently eliminate GPC3-positive HCC cells and their potential in the treatment of HCC.

EXPERIMENTAL DESIGN

T cells expressing a first-generation and third-generation GPC3-targeted CAR were prepared using lentiviral vector transduction. The in vitro and in vivo cytotoxic activities of the genetically engineered CAR T cells were evaluated against various HCC cell lines.

RESULTS

GPC3-targeted CAR T cells could efficiently kill GPC3-positive HCC cells but not GPC3-negative cells in vitro. These cytotoxic activities seemed to be positively correlated with GPC3 expression levels in the target cells. In addition, T cells expressing the third-generation GPC3-targeted CAR could eradicate HCC xenografts with high level of GPC3 expression and efficiently suppress the growth of HCC xenografts with low GPC3 expression level in vivo. The survival of the mice bearing established orthotopic Huh-7 xenografts was significantly prolonged by the treatment with the third-generation GPC3-targeted CAR T cells.

CONCLUSIONS

GPC3-targeted CAR T cells could potently eliminate GPC3-positive HCC cells, thereby providing a promising therapeutic intervention for GPC3-positive HCC.

Implications of biomarkers in human hepatocellular carcinoma pathogenesis and therapy

Hepatocellular carcinoma (HCC) is one of the most frequent tumors worldwide and accounts for approximately one-third of all malignancies. In the past decade, advances have been made to improve the prognosis of HCC, including improvement in the clinical diagnosis of early-stage HCC using molecular biomarkers and molecular-targeted therapy to treat advanced HCC. However, the diagnosis, pathogenesis and targeted therapy of HCC are not completely independent, and should be comprehensively studied. For example, a number of tumor markers provide useful clinical information not only for prognosis, but also in pathogenesis and treatment efficacy. Therefore, this review will focus on the role of several specific biomarkers implicated in the pathogenesis of HCC and several promising molecular-targeted drugs that target the biomarkers of HCC.

Circulating biomarkers in hepatocellular carcinoma

PURPOSE

Our aims are to determine levels of circulating cellular and protein biomarkers in hepatocellular carcinoma (HCC) patients and to analyse any relationships with clinical parameters.

METHODS

Fifty-four consenting patients were recruited. Circulating tumour cells (CTCs) were enumerated (by CellSearch) and characterised via filtration [by isolation by size of epithelial tumour cells (ISET)] with downstream immunohistochemistry (IHC). Glypican-3 (GPC3) expression in tumour biopsies and CTCs (by IHC) was compared, and levels of circulating caspase-cleaved and full-length cytokeratin 18 (CK18, measured using M30 and M65 ELISAs) were examined as a putative prognostic factor and marker of tumour burden.

RESULTS

CTCs were identified in 14 out of 50 (28%) patients by CellSearch and in 19 out of 19 (100%) patients by ISET. The presence of GPC3-positive CTCs by ISET was 100% concordant with the presence of GPC3-positive cells in the original tumour (n = 5). No statistically significant correlations were observed between CTC number and clinical characteristics, although trends were noted between CTC subtypes, Child-Pugh score and tumour node metastasis stage. Serum M30 and M65 levels (as continuous variables) significantly correlated with overall survival (OS) in a univariate analysis (p = 0.003 and p < 0.001, respectively); M65 levels remained statistically significant in a multivariate analysis (p = 0.029).

CONCLUSIONS

This is the first study to detect GPC3-positive CTCs in HCC, important for drug development with this target. The significant association of circulating CK18 with OS in HCC further exemplifies the utility of circulating biomarkers in cancer.

Inactivation of Wnt signaling by a human antibody that recognizes the heparan sulfate chains of glypican-3 for liver cancer therapy

Wnt signaling is important for cancer pathogenesis and is often up-regulated in hepatocellular carcinoma (HCC). Heparan sulfate proteoglycans (HSPGs) function as coreceptors or modulators of Wnt activation. Glypican-3 (GPC3) is an HSPG that is highly expressed in HCC, where it can attract Wnt proteins to the cell surface and promote cell proliferation. Thus, GPC3 has emerged as a candidate therapeutic target in liver cancer. While monoclonal antibodies to GPC3 are currently being evaluated in preclinical and clinical studies, none have shown an effect on Wnt signaling. Here, we first document the expression of Wnt3a, multiple Wnt receptors, and GPC3 in several HCC cell lines, and demonstrate that GPC3 enhanced the activity of Wnt3a/β-catenin signaling in these cells. Then we report the identification of HS20, a human monoclonal antibody against GPC3, which preferentially recognized the heparan sulfate chains of GPC3, both the sulfated and nonsulfated portions. HS20 disrupted the interaction of Wnt3a and GPC3 and blocked Wnt3a/β-catenin signaling. Moreover, HS20 inhibited Wnt3a-dependent cell proliferation in vitro and HCC xenograft growth in nude mice. In addition, HS20 had no detectable undesired toxicity in mice. Taken together, our results show that a monoclonal antibody primarily targeting the heparin sulfate chains of GPC3 inhibited Wnt/β-catenin signaling in HCC cells and had potent antitumor activity in vivo.

CONCLUSION

An antibody directed against the heparan sulfate of a proteoglycan shows efficacy in blocking Wnt signaling and HCC growth, suggesting a novel strategy for liver cancer therapy.

HCC therapies--lessons learned

The antiangiogenic multikinase inhibitor sorafenib was the first systemic agent to demonstrate a significant improvement in the overall survival of patients with advanced hepatocellular carcinoma (HCC), thereby introducing molecularly-targeted therapy in a therapeutic field of unmet needs. However, survival benefits for patients on sorafenib treatment are modest in clinical practice and advancing the field is far more challenging than initially anticipated. Molecular and clinical heterogeneity diminishes signals of potential activity in unselected populations, and underlying liver cirrhosis seals the fate of many novel targeted agents by causing relevant toxicity and mortality. The failure of subsequent randomized controlled phase III trials underscores the urgent need to identify the driver targets and to develop matched active agents with manageable toxicities in specific phase I studies in patients with cirrhosis. Refinement of phase II-III trial designs with a biomarker-enriched patient-selection process and stratification according to prognostic baseline factors is indispensable to prevent another 5-year vain endeavour in systemic therapy of HCC.

Critical analysis of the potential of targeting GPC3 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. The treatment options for patients with advanced HCC are limited, and novel treatment strategies are required urgently. Glypican-3 (GPC3), a member of the glypican family of heparan sulfate proteoglycans, is overexpressed in 72%−81% of HCC cases, and is correlated with a poor prognosis. GPC3 regulates both stimulatory and inhibitory signals, and plays a key role in regulating cancer cell growth. GPC3 is released into the serum, and so might be a useful diagnostic marker for HCC. GPC3 is also used as an immunotherapeutic target in HCC. A Phase I study of a humanized anti-GPC3 monoclonal antibody, GC33, revealed a good safety profile and potential antitumor activity, and a Phase II trial is currently ongoing. In addition, the authors’ investigator-initiated Phase I study of a GPC3-derived peptide vaccine showed good safety and tolerability, and demonstrated that the GPC3 peptide-specific cytotoxic T-lymphocyte frequency in peripheral blood correlated with overall survival in HCC patients. A sponsor-initiated Phase I clinical trial of a three-peptide cocktail vaccine, which includes a GPC3-derived peptide, is also underway. GPC3 is currently recognized as a promising therapeutic target and diagnostic marker for HCC. This review introduces the recent progress in GPC3 research, from biology to clinical impact.

Chemotherapy for advanced hepatocellular carcinoma in the sorafenib age

The kinase inhibitor sorafenib is the only systemic therapy proven to have a positive effect on survival of patients with advanced hepatocellular carcinoma (HCC). After development of sorafenib and its introduction as a therapeutic agent used in the clinic, several critical questions have been raised. Clinical parameters and biomarkers predicting sorafenib efficacy are the most important issues that need to be elucidated. Although it is difficult to know the responders in advance using conventional characteristics of patients, there are specific serum cytokines and/or gene amplification in tumor tissues that have been reported to predict efficacy of sorafenib. Risk and benefits of continuation of sorafenib beyond radiological progression is another issue to consider because no other standard therapy for advanced HCC as yet exists. In addition, effectiveness of the expanded application of sorafenib is still controversial, although a few studies have shed some light on combinational treatment with sorafenib for intermediate-stage HCC. Recently, over 50 relevant drugs have been developed and are currently under investigation. The efficacy of some of these drugs has been extensively examined, but none have demonstrated any superiority over sorafenib, so far. However, there are several drugs that have shown efficacy for treatment after sorafenib failure, and these are proceeding to further studies. To address these issues and questions, we have done extensive literature review and summarize the most current status of therapeutic application of sorafenib.

Heparan sulfate signaling in cancer

Heparan sulfate (HS) is a biopolymer consisting of variably sulfated repeating disaccharide units. The anticoagulant heparin is a highly sulfated intracellular variant of HS. HS has demonstrated roles in embryonic development, homeostasis, and human disease via non-covalent interactions with numerous cellular proteins, including growth factors and their receptors. HS can function as a co-receptor by enhancing receptor-complex formation. In other contexts, HS disrupts signaling complexes or serves as a ligand sink. The effects of HS on growth factor signaling are tightly regulated by the actions of sulfyltransferases, sulfatases, and heparanases. HS has important emerging roles in oncogenesis, and heparin derivatives represent potential therapeutic strategies for human cancers. Here we review recent insights into HS signaling in tumor proliferation, angiogenesis, metastasis, and differentiation. A cancer-specific understanding of HS signaling could uncover potential therapeutic targets in this highly actionable signaling network.

Development of a clinical chemiluminescent immunoassay for serum GPC3 and simultaneous measurements alone with AFP and CK19 in diagnosis of hepatocellular carcinoma

BACKGROUND

Glypican-3 (GPC3) is an oncofetal antigen that shows great promise as a biomarker for diagnosis of hepatocellular carcinoma (HCC), but there is no reliable kit that can be used to detect it in clinics. The aim of this study is to develop a stable performance kit for GPC3 detection in clinics.

DESIGN AND METHODS

The paired antibodies were identified through cycle-screening methods based on our previous research. Then, a double antibodies sandwich chemiluminescent immunoassay for detecting serum GPC3 was developed. The performance of the developed GPC3 diagnostic kit was evaluated by detecting the concentration of serum GPC3 and assessing its single or combined use with alpha fetoprotein (AFP) and cytokeratin 19 fragment (CK19) for HCC diagnosis.

RESULTS

The assay demonstrated a linear range of 10-800 ng/ml, the cross-reactivity rate at 0.018% (AFP), 0.020% (carcino-embryonic antigen), and 0.021% (CK19), respectively. The minimum detectable concentration was 0.05 ng/ml; the intraassay coefficient of variation (CV) and interassay CV were both less than 10%, with good stability and reproducibility. GPC3 has a high sensitivity (54.2%) and specificity (99.4%) in diagnosing HCC. The level of GPC3 in HCC was robust higher than that in healthy or other liver diseases' sera (108.67 ± 230.04 ng/ml vs. 3.99 ± 7.68 ng/ml). The diagnostic sensitivity of GPC3 single or combined with CK19 and AFP for HCC was evaluated, and the rates were 54.2 and 90.6%, respectively.

CONCLUSIONS

An applicable chemiluminescent immunoassay with stable performance against GPC3 in diagnosing HCC has been established and the combination of GPC3 with CK19 and AFP could improve the diagnostic sensitivity for HCC.

Japanese phase I study of GC33, a humanized antibody against glypican-3 for advanced hepatocellular carcinoma

GC33 is a humanized mAb against human glypican-3 (GPC3). In the first-in-human study carried out in the USA, GC33 was well tolerated and showed preliminary antitumor activity in patients with advanced hepatocellular carcinoma. This study aimed to assess the safety, tolerability, and pharmacokinetic characteristics of GC33 in Japanese patients with advanced hepatocellular carcinoma. The study design was a conventional 3 + 3 dose-escalation design to determine the maximum tolerated dose of GC33 given i.v. at 5, 10, or 20 mg/kg weekly. Immunohistochemistry was carried out on tumor biopsies to evaluate GPC3 expression. Thirteen patients were enrolled across the three dose levels, and no patients observed any dose-limiting toxicity up to the highest planned dose of 20 mg/kg. The most common adverse events were decreased lymphocyte count, decreased natural killer cell count, increased C-reactive protein, and pyrexia. Grade 3 adverse events (increased blood pressure, decreased lymphocyte count, and decreased platelet count) were observed in two or more patients. The AUCinf showed a dose-proportional increase from the 5 mg/kg dose group to the 20 mg/kg dose group. The trough concentrations of GC33 appeared to reach a steady state after the fourth to the sixth dose. Seven of the 13 patients showed stable disease, the other six showed progressive disease. Furthermore, three patients showed long-term stable disease of more than 5 months. In conclusion, GC33 given at up to 20 mg/kg weekly was well tolerated in Japanese patients with advanced hepatocellular carcinoma.

Novel hepatocellular carcinoma molecules with prognostic and therapeutic potentials

Hepatocellular carcinoma (HCC), the predominant form of primary liver cancer, is the sixth most common cancer worldwide and the third leading cause of cancer-related death. The difficulty to diagnose early cancer stages, the aggressive behaviors of HCC, and the poor effectiveness of therapeutic treatments, represent the reasons for the quite similar deaths per year and incidence number. Considering the fact that the diagnosis of HCC typically occurs in the advanced stages of the disease when the therapeutic options have only modest efficacy, the possibility to identify early diagnostic markers could be of significant benefit. So far, a large number of biomarkers have been associated to HCC progression and aggressiveness, but many of them turned out not to be of practical utility. This is the reason why active investigations are ongoing in this field. Given the huge amount of published works aimed at the identification of HCC biomarkers, in this review we mainly focused on the data published in the last year, with particular attention to the role of (1) molecular and biochemical cellular markers; (2) micro-interfering RNAs; (3) epigenetic variations; and (4) tumor stroma. It is worth mentioning that a significant number of the HCC markers described in the present review may be utilized also as targets for novel therapeutic approaches, indicating the tight relation between diagnosis and therapy. In conclusion, we believe that integrated researches among the different lines of investigation indicated above should represent the winning strategies to identify effective HCC markers and therapeutic targets.

Spontaneous and therapeutic immune responses in hepatocellular carcinoma: implications for current and future immunotherapies

Hepatocellular carcinoma (HCC) represents a major health problem in the world, ranking fifth in incidence and third in cancer-related deaths. Due to the unique immunosuppressive microenvironment of the liver, HCC develops in an immunotolerant niche posing an important obstacle to immunotherapy. A number of studies, however, have shown immunogenic properties of HCC by demonstrating spontaneous adaptive immune responses during tumor formation and progression. Furthermore, studies examining immune responses during HCC therapy have revealed that conventional treatments such as surgical resection, locoregional therapy and systemic therapy with antibodies, small molecules or chemotherapy induce adaptive immune responses that contribute to therapeutic effects. These observations have provided a basis for clinical trials involving adoptive transfers of T cells or natural killer cells, peptide and dendritic cell vaccinations or, more recently, virotherapy and inhibition of co-inhibitory molecules. Here, spontaneous and therapeutic immune responses in HCC and their implication for current and future immunotherapies are discussed.

Advanced unresectable hepatocellular carcinoma: new biologics as fresh ammunition or clues to disease understanding?

PURPOSE OF REVIEW

Hepatocellular carcinoma (HCC) is a prevalent malignancy associated with a guarded prognosis. At present, sorafenib is the only approved systemic therapy for patients with advanced disease. The effect of sorafenib on overall survival is modest and limited in time by the occurrence of drug resistance.

RECENT FINDINGS

Together with the increasing knowledge of molecular pathways involved in HCC, targeted molecules have been developed and tested in first and second line following sorafenib. These include antiangiogenic drugs, as well as biologicals inhibiting cell proliferation and survival. Recent phase III trials investigated sunitinib, linifanib, brivanib and erlotinib, but none of them were found superior to sorafenib. New findings in mechanisms of drug resistance create opportunities in the treatment of sorafenib-refractory disease, with cMET inhibition as the most promising approach. This article reviews the pathways involved in HCC and their targets as well as potential strategies for drug development in the future.

SUMMARY

Advanced HCC has been the subject of intensive clinical research following the success of sorafenib. Despite many failures, some agents show promising results in phase II trials. Targeting new pathways, using multidrug regimens and tailoring treatment guided by predictive markers should allow new successes.

Glypican-3 antibodies: a new therapeutic target for liver cancer

Glypican-3 (GPC3) is an emerging therapeutic target in hepatocellular carcinoma (HCC), even though the biological function of GPC3 remains elusive. Currently human (MDX-1414 and HN3) and humanized mouse (GC33 and YP7) antibodies that target GPC3 for HCC treatment are under different stages of preclinical or clinical development. Humanized mouse antibody GC33 is being evaluated in a phase II clinical trial. Human antibodies MDX-1414 and HN3 are under different stages of preclinical evaluation. Here, we summarize current evidence for GPC3 as a new target in liver cancer, discuss both its oncogenic function and its mode of actions for current antibodies, and evaluate potential challenges for GPC3-targeted anti-cancer therapies.

Treatment of hepatocellular carcinoma: present and future

Hepatocellular carcinoma is a major health problem. It is the sixth most common cancer worldwide and the third most common cause of cancer-related death. Despite the availability of several treatment opportunities, diagnosis is still made in an advanced phase, limiting application of most therapeutic choices that currently are based on the Barcelona Clinic Cancer Liver Classification and include surgical resection, orthotopic liver transplantation and ablative methods for very early and early disease, arterial chemoembolization for intermediate stages and systemic therapy with sorafenib for advanced hepatocellular carcinoma. Thanks to novel advancements in knowledge of molecular pathogenesis of this tumor, many new systemic agents and locoregional treatments are in different stages of clinical development and they represent an important promise of further improvements in patients' survival.

Clinical trials in hepatocellular carcinoma: an update

The success of sorafenib has spurred an explosive increase of clinical trials testing novel molecular targets and other agents in the treatment of hepatocellular carcinoma (HCC). The paradigm of the studies has been characterized by three noticeable changes. First, the molecular targets of interest have expanded from angiogenesis to cancer cell-directed oncogenic signaling pathways for advanced HCC treatment. Agents targeting EGFR, FGFR, PI3K/Akt/mTOR, TGF-β, c-Met, MEK, IGF signaling, and histone deacetylase have been actively explored. Second, the target indication has shifted from advanced stage to early or intermediate stages of disease. The feasibility of combining locoregional therapies and targeted agents, and the use of novel agents after curative treatments are currently under active investigation. Finally, the therapeutic strategy has shifted from monotherapy to combination targeted therapy. We aim to provide a comprehensive overview of newly disclosed and ongoing clinical trials for the treatment of HCC.

Novel therapeutics in hepatocellular carcinoma: how can we make progress?

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death globally, and its prevalence and impact are even more profound because sorafenib is the only systemic therapy proven to prolong survival in patients with advanced disease. Randomized phase III trials of other novel targeted agents including sunitinib, linifanib, brivanib, and the combination of sorafenib plus erlotinib have failed to improve overall survival compared with sorafenib as a single agent in the first line setting, as well as compared with placebo in the second-line setting, in the case of brivanib. These negative studies are a sobering reminder of the challenges to clinical research in HCC, including the competing comorbidity of liver dysfunction, marked clinical and biologic heterogeneity, and the unreliability of surrogate endpoints to accurately predict survival. To address these challenges, HCC-specific phase I/Ib cohorts must be used to define the maximum tolerated dose and drug exposure in this organ dysfunction population with high background rates of adverse events and little tolerance for superimposed treatment-related toxicity. Pooled analyses of contemporary randomized trials and database studies should be undertaken to define the strongest prognostic factors for stratification in future phase III studies. Research blood and archival tumor specimens should be collected from patients on clinical trials to intensify the search for biomarkers of responsive or resistant subsets, in parallel with ongoing efforts to improve on radiographic response assessment. Collectively, these and other new strategies are needed to make progress in identifying active novel therapeutics for patients with HCC.