Silencing glypican-3 expression induces apoptosis in human hepatocellular carcinoma cells

The role of glypican-3 in hepatocellular carcinoma: Insights into diagnosis and therapeutic potential

Glypican-3 (GPC-3) is predominantly found in the placenta and fetal liver, with limited expression in adult tissues. Its re-expression in hepatocellular carcinoma (HCC) and secretion into the serum highlights its potential as a diagnostic marker. GPC-3 is involved in important cellular processes such as proliferation, metastasis, apoptosis, and epithelial-mesenchymal transition through various signaling pathways including Wnt, IGF, YAP, and Hedgehog. To review the structure, biosynthesis, and post-translational modifications of GPC-3, and to elucidate its signaling mechanisms and role as a pro-proliferative protein in HCC, emphasizing its diagnostic and therapeutic potential. A comprehensive literature review was conducted, focusing on the expression of GPC-3 in various tumors, with a special emphasis on HCC. The review synthesized findings from experimental studies and clinical trials, analyzing the overexpression of GPC-3 in HCC, its differentiation from other liver diseases, and its potential as a diagnostic and therapeutic target. GPC-3 overexpression in HCC is linked to aggressive tumor behavior and poor prognosis, including shorter overall and disease-free survival. Additionally, GPC-3 has emerged as a promising therapeutic target. Ongoing investigations, including immunotherapies such as monoclonal antibodies and CAR-T cell therapies, demonstrate potential in inhibiting tumor growth and improving clinical outcomes. The review details the multifaceted roles of GPC-3 in tumorigenesis, including its impact on tumor-associated macrophages, glucose metabolism, and epithelial-mesenchymal transition, all contributing to HCC progression. GPC-3's re-expression in HCC and its involvement in key tumorigenic processes underscore its value as a biomarker for early diagnosis and a target for therapeutic intervention. Further research is warranted to fully exploit GPC-3's diagnostic and therapeutic potential in HCC management.

Single is not combined: The role of Co and Ni bioavailability on toxicity mechanisms in liver and brain cells

The two trace elements cobalt (Co) and nickel (Ni) are widely distributed in the environment due to the increasing industrial application, for example in lithium-ion batteries. Both metals are known to cause detrimental health impacts to humans when overexposed and both are supposed to be a risk factor for various diseases. The individual toxicity of Co and Ni has been partially investigated, however the underlying mechanisms, as well as the interactions of both remain unknown. In this study, we focused on the treatment of liver carcinoma (HepG2) and astrocytoma (CCF-STTG1) cells as a model for the target sites of these two metals. We investigated their effects in single and combined exposure on cell survival, cell death mechanisms, bioavailability, and the induction of oxidative stress. The combination of CoCl2 and NiCl2 resulted in higher Co levels with subsequent decreased amount of Ni compared to the individual treatment. Only CoCl2 and the combination of both metals led to RONS induction and increased GSSG formation, while apoptosis and necrosis seem to be involved in the cell death mechanisms of both CoCl2 and NiCl2. Collectively, this study demonstrates cell-type specific toxicity, with HepG2 representing the more sensitive cell line. Importantly, combined exposure to CoCl2 and NiCl2 is more toxic than single exposure, which may originate partly from the respective cellular Co and Ni content. Our data imply that the major mechanism of joint toxicity is associated with oxidative stress. More studies are needed to assess toxicity after combined exposure to elements such as Co and Ni to advance an improved hazard prediction for less artificial and more real-life exposure scenarios.

Anti HCV activity and expression inhibition of HCC markers by protein extract from Iberis gibraltarica

Abstract Hepatitis C virus infection (HCV) is the foremost reason of progressive hepatic fibrosis and cirrhosis, with an elevated risk of hepatocellular carcinoma (HCC) development. Medicinal plants have been used for human health benefits for several years, but their therapeutic potential needs to be explored. The main objective of this study was to figure out the in vitro antiviral and anticancer characteristics of total crude protein of Iberis gibraltarica against HCV and HCC. Total crude protein of Iberis gibraltarica was isolated and quantified. The level of cytotoxicity was measured against the HepG2 cell line and it shows no significant cytotoxicity at the concentration of 504µg/ml. The anti-HCV effect was determined by absolute quantification via real time RT-PCR method and viral titer was reduced up to 66% in a dose dependent manner against the total protein of Iberis gibraltarica. The anticancer potential of Iberis gibraltarica was also examined through mRNA expression studies of AFP and GPC3 genes against the total protein of Iberis gibraltarica-treated HepG2 cells. The results show up to 90% of the down-regulation expression of AFP and GPC3. The obtained results indicate the therapeutic potential of total protein of Iberis gibraltarica against HCV and hepatocellular carcinoma in vitro.

Construction of GPC3-modified Lipopolymer SiRNA Delivery System

BACKGROUND

Gene therapy has been widely concerned because of its unique therapeutic mechanism. However, due to the lack of safe and effective carries, it has not been widely used in clinical practice. Glypican 3 (GPC3) is a highly specific proteoglycan for hepatocellular carcinoma and is a potential diagnostic and therapeutic target for hepatocellular carcinoma. Herein, to monitor the effect of gene therapy and enhance the transfection efficiency of gene carriers, GPC3-modified lipid polyethyleneimine-modified superparamagnetic nanoparticle (GLPS), a type of visualized carrier for siRNA (small-interfering RNA) targeting the liver, was prepared.

METHODS

We performed in vitro gene silencing, cytotoxicity, and agarose gel electrophoresis to identify the optimal GLPS formulation. In vitro MRI and Prussian blue staining verified the liver-targeting function of GLPS. We also analyzed the biocompatibility of GLPS by co-culturing with rabbit red blood cells. Morphological changes were evaluated using HE staining.

RESULTS

The GLPS optimal formulation consisted of LPS and siRNA at a mass ratio of 25:1 and LPS and DSPE-PEG-GPC3 at a molar ratio of 2:3. GLPS exhibited evident liver-targeting function. In vitro, we did not observe morphological changes in red blood cells or hemolysis after co-culture. In vivo, routine blood analysis revealed no abnormalities after GLPS injection. Moreover, the tissue morphology of the kidney, spleen, and liver was normal without injury or inflammation.

CONCLUSION

GLPS could potentially serve as an effective carrier for liver-targeted MRI monitoring and siRNA delivery.

GPC3-Unc5 receptor complex structure and role in cell migration

Neural migration is a critical step during brain development that requires the interactions of cell-surface guidance receptors. Cancer cells often hijack these mechanisms to disseminate. Here, we reveal crystal structures of Uncoordinated-5 receptor D (Unc5D) in complex with morphogen receptor glypican-3 (GPC3), forming an octameric glycoprotein complex. In the complex, four Unc5D molecules pack into an antiparallel bundle, flanked by four GPC3 molecules. Central glycan-glycan interactions are formed by N-linked glycans emanating from GPC3 (N241 in human) and C-mannosylated tryptophans of the Unc5D thrombospondin-like domains. MD simulations, mass spectrometry and structure-based mutants validate the crystallographic data. Anti-GPC3 nanobodies enhance or weaken Unc5-GPC3 binding and, together with mutant proteins, show that Unc5/GPC3 guide migrating pyramidal neurons in the mouse cortex, and cancer cells in an embryonic xenograft neuroblastoma model. The results demonstrate a conserved structural mechanism of cell guidance, where finely balanced Unc5-GPC3 interactions regulate cell migration.

Extending traditional antibody therapies: Novel discoveries in immunotherapy and clinical applications

Immunotherapy has been well regarded as one of the safer and antigen-specific anti-cancer treatments compared to first-generation chemotherapy. Since Coley's discovery, researchers focused on engineering novel antibody-based therapies. Including artificial and modified antibodies, such as antibody fragments, antibody-drug conjugates, and synthetic mimetics, the variety of immunotherapy has been rapidly expanding in the last few decades. Genetic and chemical modifications to monoclonal antibody have been brought into academia, in vivo trials, and clinical applications. Here, we have looked around antibodies overall. First, we elucidate the antibody structure and its cytotoxicity mechanisms. Second, types of therapeutic antibodies are presented. Additionally, there is a summarized list of US Food and Drug Administration (FDA)-approved therapeutic antibodies and recent clinical trials. This review provides a comprehensive overview of both the general function of therapeutic antibodies and a few main variations in development, including recent advent with the proposed mechanism of actions, and we introduce types of therapeutic antibodies, clinical trials, and approved commercial immunotherapeutic drugs.

Mechanisms and Clinical Trials of Hepatocellular Carcinoma Immunotherapy

Hepatocellular carcinoma (HCC), one of the most common and lethal tumors worldwide, is usually not diagnosed until the disease is advanced, which results in ineffective intervention and unfavorable prognosis. Small molecule targeted drugs of HCC, such as sorafenib, provided only about 2.8 months of survival benefit, partially due to cancer stem cell resistance. There is an urgent need for the development of new treatment strategies for HCC. Tumor immunotherapies, including immune check point inhibitors, chimeric antigen receptor T cells (CAR-T) and bispecific antibodies (BsAb), have shown significant potential. It is known that the expression level of glypican-3 (GPC3) was significantly increased in HCC compared with normal liver tissues. A bispecific antibody (GPC3-S-Fabs) was reported to recruit NK cells to target GPC3 positive cancer cells. Besides, bispecific T-cell Engagers (BiTE), including GPC3/CD3, an aptamer TLS11a/CD3 and EpCAM/CD3, were recently reported to efficiently eliminate HCC cells. It is known that immune checkpoint proteins programmed death-1 (PD-1) binding by programmed cell death-ligand 1 (PD-L1) activates immune checkpoints of T cells. Anti-PD-1 antibody was reported to suppress HCC progression. Furthermore, GPC3-based HCC immunotherapy has been shown to be a curative approach to prolong the survival time of patients with HCC in clinically trials. Besides, the vascular endothelial growth factor (VEGF) inhibitor may inhibit the migration, invasion and angiogenesis of HCC. Here we review the cutting-edge progresses on mechanisms and clinical trials of HCC immunotherapy, which may have significant implication in our understanding of HCC and its immunotherapy.

Heparan sulfate proteoglycans and their modification as promising anticancer targets in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of primary liver cancer. Despite advancements in the treatment strategies of HCC, there is an urgent requirement to identify and develop novel therapeutic drugs that do not lead to resistance. These novel agents should have the potential to influence the primary mechanisms participating in the pathogenesis of HCC. Heparan sulfate proteoglycans (HSPGs) are major elements of the extracellular matrix that perform structural and signaling functions. HSPGs protect against invasion of tumor cells by preventing cell infiltration and intercellular adhesion. Several enzymes, such as heparanase, matrix metalloproteinase-9 and sulfatase-2, have been reported to affect HSPGs, leading to their degradation and thus enhancing tumor invasion. In addition, some compounds that are produced from the degradation of HSPGs, including glypican-3 and syndecan-1, enhance tumor progression. Thus, the identification of enzymes that affect HSPGs or their degradation products in HCC may lead to the development of novel therapeutic targets. The present review discusses the main enzymes and compounds associated with HSPGs, and their involvement with the pathogenicity of HCC.

Novel molecular targets in hepatocellular carcinoma

Globally, hepatocellular carcinoma (HCC) is a leading cause of cancer and cancer-related deaths. The therapeutic efficacy of locoregional and systemic treatment in patients with advanced HCC remains low, which results in a poor prognosis. The development of sorafenib for the treatment of HCC has resulted in a new era of molecular targeted therapy for this disease. However, the median overall survival was reported to be barely higher in the sorafenib treatment group than in the control group. Hence, in this review we describe the importance of developing more effective targeted therapies for the management of advanced HCC. Recent investigations of molecular signaling pathways in several cancers have provided some insights into developing molecular therapies that target critical members of these signaling pathways. Proteins involved in the Hedgehog and Notch signaling pathways, Polo-like kinase 1, arginine, histone deacetylases and Glypican-3 can be potential targets in the treatment of HCC. Monotherapy has limited therapeutic efficacy due to the development of inhibitory feedback mechanisms and induction of chemoresistance. Thus, emphasis is now on the development of personalized and combination molecular targeted therapies that can serve as ideal therapeutic strategies for improved management of HCC.

Sulfated syndecan 1 is critical to preventing cellular senescence by modulating fibroblast growth factor receptor endocytosis

Cellular senescence can be triggered by various intrinsic and extrinsic stimuli. We previously reported that silencing of 3'-phosphoadenosine 5'-phosphosulfate synthetase 2 (PAPSS2) induces cellular senescence through augmented fibroblast growth factor receptor 1 (FGFR1) signaling. However, the exact molecular mechanism connecting heparan sulfation and cellular senescence remains unclear. Here, we investigated the potential involvement of heparan sulfate proteoglycans (HSPGs) in augmented FGFR1 signaling and cellular senescence. Depletion of several types of HSPGs revealed that cells depleted of syndecan 1 (SDC1) exhibited typical senescence phenotypes, and those depleted of PAPSS2-, SDC1-, or heparan sulfate 2-O sulfotransferase 1 (HS2ST1) showed decreased FGFR1 internalization along with hyperresponsiveness to and prolonged activation of fibroblast growth factor 2 (FGF2)-stimulated FGFR1- v-akt murine thymoma viral oncogene homolog (AKT) signaling. Clathrin- and caveolin-mediated FGFR1 endocytosis contributed to cellular senescence through the FGFR1-AKT-p53-p21 signaling pathway. Dynasore treatment triggered senescence phenotypes, augmented FGFR1-AKT-p53-p21 signaling, and decreased SDC1 expression. Finally, the replicatively and prematurely senescent cells were characterized by decreases of SDC1 expression and FGFR1 internalization, and an increase in FGFR1-AKT-p53-p21 signaling. Together, our results demonstrate that properly sulfated SDC1 plays a critical role in preventing cellular senescence through the regulation of FGFR1 endocytosis.

Cobalt Chloride Induced Apoptosis by Inhibiting GPC3 Expression via the HIF-1α/c-Myc Axis in HepG2 Cells

Purpose

To investigate the role of glypican-3 (GPC3) in cobalt chloride (CoCl₂)-induced cell apoptosis in hepatocellular carcinoma.

Methods

HepG2 cells were treated with CoCl₂ in the absence or presence of GPC3 plasmid transfection. Cell viability and apoptosis were assessed by MTT assay and flow cytometry, respectively. The expression of GPC3, hypoxia-inducible factor 1α (HIF-1α), c-myc, sp1, poly-ADP-ribose polymerase (PARP) and caspase-3 was determined by real-time PCR, Western blotting, and immunofluorescence after the cells were treated with different concentrations of CoCl₂ or siRNA targeting HIF-1α.

Results

CoCl₂ significantly inhibited the proliferation of HepG2 cells and induced apoptosis. Additionally, the expression of GPC3 mRNA and protein was decreased, and overexpression of GPC3 attenuated the tumour inhibiting effects. Further studies showed that CoCl₂ increased the expression of HIF-1α while reducing the expression of sp1 and c-myc; knockdown of HIF-1α elevated the expression of GPC3, sp1, and c-myc.

Conclusion

CoCl₂ inhibited the growth of HepG2 cells through downregulation of GPC3 expression via the HIF-1α/c-myc axis.

Autophagy suppresses proliferation of HepG2 cells via inhibiting glypican-3/wnt/β-catenin signaling

Introduction

Autophagy plays an important role in the growth and survival of hepatocellular carcinoma (HCC) cells through several target proteins or signaling pathways. Glypican-3 (GPC3) is a new reliable HCC marker, which is involved in tumor growth in HCC, primarily mediated by wnt/β-catenin signaling.

Objective

The present study aimed to identify the role of autophagy in the proliferation of HepG2 cells through GPC3/wnt/β-catenin signaling.

Results and discussion

Results demonstrated that induction of autophagy by nutrition starvation and rapamycin treatment led to the downregulation of GPC3 expression in HepG2 cells, accompanied by the decreased expression of wnt downstream target genes (β-catenin, c-myc and cyclin D1). On the other hand, inhibition of autophagy by 3-methyl adenine (3-MA) could rescue rapamycin-directed downregulation of GPC3 and wnt/β-catenin target genes and augment the proliferation of HepG2 cells. Furthermore, interference of GPC3 by siRNA suppressed wnt/β-catenin signaling and attenuated 3-MA stimulation of HepG2 cell proliferation. More interestingly, the mRNA of GPC3 remained unchanged when the protein levels of GPC3 were decreased by autophagy activation, suggesting that induction of autophagy may accelerate the degradation of GPC3.

Conclusion

These results suggest that autophagy suppresses proliferation of HepG2 cells partially by inhibition of GPC3/wnt/β-catenin signaling.

Role of Glypican-3 in the growth, migration and invasion of primary hepatocytes isolated from patients with hepatocellular carcinoma

BACKGROUND

Recently, Glypican-3 (GPC3) has been identified as a potential hepatocellular carcinoma (HCC) diagnostic and/or therapeutic target. GPC3 has been found to be up-regulated in HCC and to be absent in normal and cirrhotic liver. As yet, however, the molecular characteristics of GPC3 and its role in HCC cell physiology and development are still undefined.

METHODS

Human hepatocyte cultures were established from 10 HCC patients. Additional liver samples were obtained from 5 patients without cirrhosis and/or HCC. Soft agar colony formation, (co-)immunofluorescence and Western blot assays were used to characterize the hapatocyte cultures. The expression of GPC3 in the hepatocytes was silenced using siRNA, after which, apoptosis, scratch wound migration and transwell invasion assays were performed.

RESULTS

We found that in HCC precursor hepatocytes GPC3 is increasingly expressed in different forms and at different locations, i.e., a non-cleaved form (70 kDa) was found to be localized in the cytoplasm while a N-terminal cleaved form (N-GPC3: 40 kDa) was fond to be localized in the cytoplasm and at the extracellular side of hepatocyte membranes. In addition, we found that the non-cleaved form of GPC3 co-localizes with Furin-Convertase in the Golgi apparatus. We also found that, similar to GPC3, Furin-Convertase is expressed in HCC precursor cells, suggesting a role in GPC3 processing. Subsequent siRNA-mediated GPC3 silencing resulted in a temporary inhibition of cell proliferation, migration and ivasion, while inducing apoptosis in transformed hepatocytes.

CONCLUSION

Our data reveal new aspects of the role of GPC3 in early hepatocyte transformation. In addition we conclude that GPC3 may serve as a new HCC immune-therapeutic target.

Overexpression of Glypican 3 Promotes Proliferation, Regulates Cell Cycle Progression, and Inhibits Apoptosis of Human Fetal Osteoblastic Cell Line 1.19

Craniosynostosis is a complex disease condition, which involves premature fusion of cranial vault sutures and lacks desirable treatment. Previous studies have demonstrated decreased proliferation rate of osteoblasts and downregulated expression of glypican 3 (GPC3) in syndromic craniosynostosis patients. In this study, quantitative and qualitative analysis were utilized to assess the effect of GPC3 in human fetal osteoblastic cell line, hFOB 1.19. Lentiviral transfection efficiency with green fluorescent protein images was obtained after 72 hours. Western Blot and quantitative real-time polymerase chain reaction analysis results indicated that GPC3 was overexpressed in hFOB 1.19 cells transfected with recombinant lentivirus LV-GPC3-GFP. Cell proliferation was assessed by CCK-8 assay and cell cycle progression and apoptosis were analyzed by flow cytometric assay. Results revealed that GPC3 promoted cell viability, induced cell cycle entry into S phase, and inhibited cell apoptosis. These findings provide novel ideas in understanding the pathogenesis of craniosynostosis. It also provides novel insights in the treatment of craniosynostosis by targeting GPC3.

Glypican-3: A promising biomarker for hepatocellular carcinoma diagnosis and treatment

Liver cancer is the second leading cause of cancer-related deaths, and hepatocellular carcinoma (HCC) is the most common type. Therefore, molecular targets are urgently required for the early detection of HCC and the development of novel therapeutic approaches. Glypican-3 (GPC3), an oncofetal proteoglycan anchored to the cell membrane, is normally detected in the fetal liver but not in the healthy adult liver. However, in HCC patients, GPC3 is overexpressed at both the gene and protein levels, and its expression predicts a poor prognosis. Mechanistic studies have revealed that GPC3 functions in HCC progression by binding to molecules such as Wnt signaling proteins and growth factors. Moreover, GPC3 has been used as a target for molecular imaging and therapeutic intervention in HCC. To date, GPC3-targeted magnetic resonance imaging, positron emission tomography, and near-infrared imaging have been investigated for early HCC detection, and various immunotherapeutic protocols targeting GPC3 have been developed, including the use of humanized anti-GPC3 cytotoxic antibodies, treatment with peptide/DNA vaccines, immunotoxin therapies, and genetic therapies. In this review, we summarize the current knowledge regarding the structure, function, and biology of GPC3 with a focus on its clinical potential as a diagnostic molecule and a therapeutic target in HCC immunotherapy.

Characterization of a new monoclonal anti-glypican-3 antibody specific to the hepatocellular carcinoma cell line, HepG2

AIM

To characterize the antigen on HepG2 cell that is specifically recognized by a new monoclonal antibody raised against human liver heparan sulfate proteoglycan (HSPG), clone 1E4-1D9.

METHODS

The antigen recognized by mAb 1E4-1D9 was immunoprecipitated and its amino acid sequence was analyzed LC/MS. The transmembrane domain, number of cysteine residues, and glycosylation sites were predicted from these entire sequences. Data from amino acid analysis was aligned with glypican-3 (https://www.ebi.ac.uk/Tools/msa/clustalo/). The competitive reaction of mAb 1E4-1D9 and anti-glypican-3 on HepG2 cells was demonstrated by indirect immunofluorescence and analyzed by flow cytometry. Moreover, co-immunoprecipitation of mAb 1E4-1D9 and anti-glypican-3 was performed in HepG2 cells by Western immunoblotting. The recognition by mAb 1E4-1D9 of a specific epitope on solid tumor and hematopoietic cell lines was studied using indirect immunofluorescence and analyzed by flow cytometry.

RESULTS

Monoclonal antibody 1E4-1D9 reacted with an HSPG isolated from human liver and a band of 67 kD was detected under both reducing and non-reducing conditions. The specific antigen pulled down by mAb 1E4-1D9, having a MW of 135 kD, was analyzed. The results showed two sequences of interest, gi30722350 (1478 amino acid) and gi60219551 (1378 amino acid). In both sequences no transmembrane regions were observed. Sequence number gi30722350 was 99.7% showed a match to FYCO1, a molecule involved in induction of autophagy. Sequence number gi60219551 contained 15 cysteines and 11 putative glycosylation sites with 6 predicted N-glycosylation sites. It was also matched with all PDZ domain proteins. Moreover, it showed an 85.7% match to glypican-3. Glypican-3 on HepG2 cells competitively reacted with both phycoerythrin-conjugated anti-glypican-3 and mAb 1E4-1C2 and resulted in an increase of double-stained cell population when higher concentration of mAb 1E4-1D9 was used. Moreover, antigens precipitated from HepG2 cell by anti-glypican-3 could be detected by mAb 1E4-1D9 and vice versa. The recognition of antigens, on other solid tumor cell lines, by mAb 1E4-1D9 was studied. The results demonstrated that mAb 1E4-1D9 reacted with Huh7, HepG2, HT29, MCF7, SW620, Caco2, B16F1, U937, K562 and Molt4 cells. It was also found to be weakly positive to SW1353 and HL60 and negative to H460 and Hela cell lines.

CONCLUSION

All findings show that mAb 1E4-1D9 specifically recognizes glypican-3. Moreover, a new partner molecule of glypican-3, FYCO1 is proposed based on the results from co-precipitation studies.

Codelivery of sorafenib and GPC3 siRNA with PEI-modified liposomes for hepatoma therapy

A novel liposomal system incorporating branched PEI was prepared to efficiently codeliver sorafenib and GPC3 siRNA for hepatocellular carcinoma therapy.

Prediction and preliminary screening of HLA-A*0201-restricted epitope peptides of human GPC3

In response to the limited therapeutic option for hepatocellular carcinoma (HCC), immunotherapy as a promising approach points out a new direction to the cure of tumours through specific recognition and elimination of tumour cells by the immunity-enhanced autologous immunocytes of patients. Few effective tumour antigens, however, are alternative in addition to alpha fetoprotein or tumour cell lysates. Recent studies have demonstrated that glypican-3 (GPC3) is not only a promising diagnostic marker, but also ideal therapeutic target to HCC. In this study, potential HLA-A*0201 GPC3 peptides were screened with three epitope prediction software, the binding affinity of 13 predicted epitopes with high scores was determined by T2 cells binding assay and four optimal epitopes were identified. This is the first study in which the optimal HLA-A*0201 GPC3 epitopes were screened from a large number of candidates predicted by three software. The optimized HLA-A*0201 GPC3 peptides will provide new epitope candidates for HCC immunotherapy.

Oncofetal glypican-3: Specific diagnosis and targeted-therapy for primary liver cancer

The development and progression of primary hepatocellular cancer (PHC) are a multi- factorial, multi-step, and multi-center complex process. Its early diagnosis and effective treatments are of the most importance. Glypican-3 (GPC-3) plays a crucial role in PHC progression. Increased GPC-3 expression has been found during hepatocyte malignant transformation. GPC-3 levels in PHC patients are related to HBV infection, TNM stage, periportal cancerous embolus, and extra-hepatic metastasis. Circulating GPC-3 or GPC-3 mRNA with AFP enhances the positive rate up to 94.3% for PHC diagnosis. Down-regulating GPC-3 by specific siRNA could alter liver cancer cell biological behaviors such as migration, metastasis, and invasion; and inhibit nude mouse xenograft growth with decreased β-catenin, p-GSK3β, and cyclin D1 expression, suggesting that oncofetal GPC-3 is not only a specific diagnostic biomarker for PHC, but also a promising target for PHC therapy.

Diagnostic and prognostic significance of glypican 5 and glypican 6 gene expression levels in gastric adenocarcinoma

Gastric Cancer is one of the most common malignancies worldwide and the second most common cause of cancer-related mortality. Previous studies revealed several genetic alterations specific to gastric cancer. In this study, we aimed to investigate the diagnostic and prognostic significance of the expression levels of the glypican 5 and glypican 6 genes (GPC5 and GPC6, respectively) in gastric cancer. For this purpose, GPC5 and GPC6 expression was quantitatively determined by quantitative polymerase chain reaction method in normal gastric mucosa and intestinal type gastric adenocarcinoma samples from 35 patients. The expression levels of GPC5 and GPC6 were compared between normal and tumor tissues. Additionally, the association of the expression levels in tumor tissues with several clinicopathological parameters was evaluated. Although GPC5 was not expressed in any of the samples, the expression of GPC6, which was detected in both groups, was found to be significantly higher in tumor tissues compared to that in normal samples (P=0.039). However, there was no statistically significant association between GPC6 expression and any of the clinicopathological parameters investigated (P>0.05). Our findings suggested that an increase in GPC6 expression levels may be implicated in gastric cancer development, but not in cancer progression.

Evaluation of antiglypican-3 therapy as a promising target for amelioration of hepatic tissue damage in hepatocellular carcinoma

In Egypt, hepatocellular carcinoma (HCC) was predicted to continue to rise over the next few decades causing a national problem. Meanwhile, glypican-3 (GPC3), a highly expressed glypican, has emerged as a potential target for HCC immunotherapy. Therefore, we aimed to identify the impact of blocking GPC3 on liver damage in HCC as well as a possible mechanism. Fifty four HCC patients, 20 cirrhotic patients and 10 healthy subjects were recruited. Serum levels of GPC3, sulfatase-2 (SULF-2), heparan sulfate proteoglycan (HSPG), insulin-like growth factor-II (IGF-II) were measured by ELISA. In parallel, HCC was induced in 40 male Sprague-Dawley rats in presence/absence of antiGPC-3. Liver impairment was detected by investigating liver sections stained with hematoxylin/eosin and serum α-fetoprotein (AFP). Liver homogenates of GPC3, SULF-2, and HSPG were measured by ELISA. Gene expression of caspase-3 and IGF-II were assayed by RT-PCR. HCC patients showed significant elevated serum levels of GPC3, IGF-II and SULF-2 accompanied by decreased HSPG. However, treatment of HCC rats with antiGPC-3 significantly reduced serum AFP and showed nearly normal hepatocytes. In addition, antiGPC-3 significantly reduced elevated liver homogenates protein levels of GPC3 and SULF-2 and gene expression of IGF-II and caspase-3. antiGPC-3 restored the reduced hepatic HSPG. antiGPC-3 showed anti-tumor activity as well as hepatoprotective effects. antiGPC-3-chemoprotective effect can be explained by forced reduction of IGF-II expression, restoration of HSPGs, deactivation of SULF-2 and reduction of gene expression of caspase-3. Targeting GPC3 is a promising therapeutic approach for HCC.

GPC3 reduces cell proliferation in renal carcinoma cell lines

BACKGROUND

Glypican 3 (GPC3) is a member of the family of glypican heparan sulfate proteoglycans (HSPGs). The GPC3 gene may play a role in controlling cell migration, negatively regulating cell growth and inducing apoptosis. GPC3 is downregulated in several cancers, which can result in uncontrolled cell growth and can also contribute to the malignant phenotype of some tumors. The purpose of this study was to analyze the mechanism of action of the GPC3 gene in clear cell renal cell carcinoma.

METHODS

Five clear cell renal cell carcinoma cell lines and carcinoma samples were used to analyze GPC3 mRNA expression (qRT-PCR). Then, representative cell lines, one primary renal carcinoma (786-O) and one metastatic renal carcinoma (ACHN), were chosen to carry out functional studies. We constructed a GPC3 expression vector and transfected the renal carcinoma cell lines, 786-O and ACHN. GPC3 overexpression was analyzed using qRT-PCR and immunocytochemistry. We evaluated cell proliferation using MTT and colony formation assays. Flow cytometry was used to evaluate apoptosis and perform cell cycle analyses.

RESULTS

We observed that GPC3 is downregulated in clear cell renal cell carcinoma samples and cell lines compared with normal renal samples. GPC3 mRNA expression and protein levels in 786-O and ACHN cell lines increased after transfection with the GPC3 expression construct, and the cell proliferation rate decreased in both cell lines following overexpression of GPC3. Further, apoptosis was not induced in the renal cell carcinoma cell lines overexpressing GPC3, and there was an increase in the cell population during the G1 phase in the cell cycle.

CONCLUSION

We suggest that the GPC3 gene reduces the rate of cell proliferation through cell cycle arrest during the G1 phase in renal cell carcinoma.

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.

Prognostic and clinicopathological significance of glypican-3 overexpression in hepatocellular carcinoma: A meta-analysis

AIM: To investigate the prognostic and clinicopathological significance of glypican-3 (GPC3) overexpression in hepatocellular carcinoma (HCC).

METHODS: Publications were searched using PubMed, EMBASE, the Cochrane Library and the Chinese Biomedical Literature Database up to March 2013. Inclusion and exclusion criteria were established to screen eligible studies for meta-analysis. The hazard ratios (HRs) of the eligible studies were pooled using RevMan 5.2 software to evaluate the impact of GPC3 overexpression on overall survival (OS) and disease-free survival (DFS) in HCC patients. The correlation between GPC3 expression and clinicopathological parameters of HCC was also analyzed.

RESULTS: A total of five studies with 493 patients were included in the meta-analysis. The combined HRs indicated that GPC3 overexpression can predict poor OS (n = 362 in 3 studies, HR = 2.18, 95%CI: 1.47-3.24, Z = 3.86, P = 0.0001) and DFS (n = 325 in 3 studies, HR = 2.05, 95%CI: 1.43-2.93, Z = 3.94, P < 0.0001) in HCC patients without heterogeneity. Egger’s and Begg’s tests were applied to detect publication bias, and the results showed that there was no evidence of publication bias detected in the OS studies (the P value for Egger’s test was 0.216) or DFS studies (the P value for Egger’s test was 0.488). The combined odds ratios (ORs) suggested that GPC3 expression tends to be associated with tumor vascular invasion (OR = 2.74, 95%CI: 1.15-6.52, P = 0.02), hepatic cirrhosis (OR = 2.10, 95%CI: 1.31-3.36, P = 0.002), poor tumor differentiation (OR = 0.22, 95%CI: 0.13-0.40, P < 0.00001) and advanced TNM stage (OR = 0.31, 95%CI: 0.18-0.51, P < 0.00001).

CONCLUSION: From this study, we conclude that GPC3 overexpression tends to be associated with a poor prognosis (poor OS or DFS) in HCC.

MicroRNA-520c-3p inhibits hepatocellular carcinoma cell proliferation and invasion through induction of cell apoptosis by targeting glypican-3

AIM

Glypican-3 (GPC3) is a membrane-associated heparan sulfate proteoglycan involved in regulation of cell proliferation, cell survival, cell migration and differentiation process. MicroRNAs (miRNAs) are single-stranded, non-coding functional RNAs that are important in many biological processes. GPC3 and miRNAs have been found to play essential roles in the development and progression of hepatocellular carcinoma (HCC). However, little information about the relationship between GPC3 and miRNAs is available nowadays. Therefore, this study aims to examine the relationship between GPC3 and miRNAs.

METHODS

Dual-luciferase reporter assay was used to validate the direct target of GPC3. Fluorescence quantitative PCR and Western blotting were used to examined the gene expression at mRNA and protein levels. Cell apoptosis was evaluated by flow cytometric analysis and Annexin V-FITC staining. Invasion of cells was evaluated by Transwell matrigel assay.

RESULTS

The results showed that miR-520c-3p could specifically target GPC3 in HCC cells. GPC3 protein levels decreased with unchanged transcription efficiency after miRNA transfection, and there was negative correlation of miR-520c-3p expression in HCC in relate to GPC3 protein levels. Moreover, miR-520c-3p not only induced HCC cell apoptosis, but also inhibited the growth and invasion of the cells. Interestingly, overexpression of GPC3 could effectively reverse apoptosis induced by miR-520c-3p transfection in HCC.

CONCLUSIONS

Taken together, these results supported that miR-520c-3p may decrease GPC3 protein levels to inhibit proliferation of HCC cells. Therefore, GPC3 could be a new target for genetic diagnosis and treatment of HCC.

Disulfiram eradicates tumor-initiating hepatocellular carcinoma cells in ROS-p38 MAPK pathway-dependent and -independent manners

Tumor-initiating cells (TICs) play a central role in tumor development, metastasis, and recurrence. In the present study, we investigated the effect of disulfiram (DSF), an inhibitor of aldehyde dehydrogenase, toward tumor-initiating hepatocellular carcinoma (HCC) cells. DSF treatment suppressed the anchorage-independent sphere formation of both HCC cells. Flow cytometric analyses showed that DSF but not 5-fluorouracil (5-FU) drastically reduces the number of tumor-initiating HCC cells. The sphere formation assays of epithelial cell adhesion molecule (EpCAM)⁺ HCC cells co-treated with p38-specific inhibitor revealed that DSF suppresses self-renewal capability mainly through the activation of reactive oxygen species (ROS)-p38 MAPK pathway. Microarray experiments also revealed the enrichment of the gene set involved in p38 MAPK signaling in EpCAM⁺ cells treated with DSF but not 5-FU. In addition, DSF appeared to downregulate Glypican 3 (GPC3) in a manner independent of ROS-p38 MAPK pathway. GPC3 was co-expressed with EpCAM in HCC cell lines and primary HCC cells and GPC3-knockdown reduced the number of EpCAM⁺ cells by compromising their self-renewal capability and inducing the apoptosis. These results indicate that DSF impaired the tumorigenicity of tumor-initiating HCC cells through activation of ROS-p38 pathway and in part through the downregulation of GPC3. DSF might be a promising therapeutic agent for the eradication of tumor-initiating HCC cells.

Overexpression of heparanase in ovarian cancer and its clinical significance

It has been reported that heparanase (HPSE) is overexpressed in ovarian cancer and is associated with tumor invasion and metastasis. However, a systematic study on the contribution of HPSE to tumor metastasis is rarely reported. In this study, based on the measurement of HPSE serum concentration, the expression of HPSE at both the mRNA and protein levels in tumors and its effects on the biological behaviors of cancer cells, we elucidated the role of HPSE in tumor invasion and metastasis in ovarian cancer and concluded that either the expression of HPSE in cancer and/or the serum concentration of HPSE may be a useful biomarker for the evaluation of surgery effects and prognosis prediction.

Targeted glypican-3 gene transcription inhibited the proliferation of human hepatoma cells by specific short hairpin RNA

Hepatocellular carcinoma (HCC) is a highly chemoresistant cancer with no effective systemic therapy. Despite of surgical or locoregional therapies, prognosis remains poor because of high tumor recurrence or progression, and currently, there are no well-established effective adjuvant therapies. Glypican-3 (GPC-3) is specifically overexpressed in hepatoma and perhaps is a valuable molecular target for HCC therapy. In this present study, the effect of silencing GPC-3 gene transcription on human HepG2 cell proliferation was investigated by constructing GPC-3 short hairpin RNA (shRNA) plasmid. After HepG2 cells were transfected with the most efficient shRNA, GPC-3 mRNA expression (90.4 %) was inhibited significantly and estimated by fluorescence quantitative reverse transcriptase-polymerase chain reaction, and the result was accordance with downregulation at the protein level. The percentage of the cell proliferation was down to 28.9 % in the shRNA group and 19.9 % in the shRNA plus sorafenib group. The cell cycles were arrested in the G₁ phase (65.6 %) and the apoptosis rate was increasing (66.75 %) in the shRNA1 group with significant alteration compared with that in the negative-shRNA group. Specific shRNA might intervene effectively GPC-3 activation and inhibit tumor cell proliferation, suggesting that GPC-3 gene should be a potential molecular target for HCC therapy.