Targeting of hepatocellular carcinoma with glypican-3-targeting peptide ligand

Integrin α6 Targeted Near Infrared Fluorescent Imaging and Photoacoustic Imaging of Hepatocellular Carcinoma in Mice

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is the fourth most common cause of cancer-related death and ranks sixth in terms of incident cases worldwide. The purpose of this study was to develop an effective and sensitive method to distinguish liver cancer tissues from normal tissues in HCC patients. Integrin α6 is a promising cell surface target for molecular imaging of HCC, where it is overexpressed and is a prognostic biomarker. We previously identified an integrin α6-targeted peptide CRWYDENAC (RWY) that has been used for positron emission tomography (PET) imaging of HCC in mouse models.

METHODS

We labeled the integrin α6-targeted RWY peptide with cyanine 7 (Cy7) to form an optical probe (Cy7-RWY) for near infrared fluorescent (NIRF) and photoacoustic (PA) imaging in HCC. Mice transplanted with subcutaneous HCC-LM3 or orthotopic HCC-H22 cells that overexpressed integrin α6 were intravenously injected with Cy7-RWY and its corresponding Cy7-control. NIRF and PA images of mice were collected from 0 to 48 h after injection.

RESULTS

Both NIRF and PA signals started to accumulate in the tumor 2 h after injection of Cy7-RWY and peaked at 24 h.

CONCLUSIONS

Cy7-RWY is a promising optical probe for NIRF and PA imaging of HCC in mice, and has potential clinical application for HCC detection.

Novel Nanotechnology Approaches to Overcome Drug Resistance in the Treatment of Hepatocellular Carcinoma: Glypican 3 as a Useful Target for Innovative Therapies

Hepatocellular carcinoma (HCC) is the second most lethal tumor, with a 5-year survival rate of 18%. Early stage HCC is potentially treatable by therapies with curative intent, whereas chemoembolization/radioembolization and systemic therapies are the only therapeutic options for intermediate or advanced HCC. Drug resistance is a critical obstacle in the treatment of HCC that could be overcome by the use of targeted nanoparticle-based therapies directed towards specific tumor-associated antigens (TAAs) to improve drug delivery. Glypican 3 (GPC3) is a member of the glypican family, heparan sulfate proteoglycans bound to the cell surface via a glycosylphosphatidylinositol anchor. The high levels of GPC3 detected in HCC and the absence or very low levels in normal and non-malignant liver make GPC3 a promising TAA candidate for targeted nanoparticle-based therapies. The use of nanoparticles conjugated with anti-GPC3 agents may improve drug delivery, leading to a reduction in severe side effects caused by chemotherapy and increased drug release at the tumor site. In this review, we describe the main clinical features of HCC and the common treatment approaches. We propose the proteoglycan GPC3 as a useful TAA for targeted therapies. Finally, we describe nanotechnology approaches for anti-GPC3 drug delivery systems based on NPs for HCC treatment.

Peptide-Conjugated Aggregation-Induced Emission Fluorogenic Probe for Glypican-3 Protein Detection and Hepatocellular Carcinoma Cells Imaging

Hepatocellular carcinoma (HCC) is a malignant tumor with high morbidity and mortality on a global scale, and the development of accurate detection and imaging methods for HCC cells is urgently needed. Herein, by connecting peptide L5, which can specifically bind to the overexpressed Glypican-3 (GPC-3) protein of HCC cells with aggregation-induced emission (AIE) moiety ammonium cation-functionalized 9,10-distyrylanthracene (NDSA) via the “click” reaction, we synthesized a fluorescent probe NDSA-L5. In an aqueous solution, the probe shows weak emission, whereas, in the presence of the GPC-3 protein, bright fluorescence can be obtained since NDSA-L5 binds to the GPC-3 protein, leading to the restricted intramolecular movement of AIE-active NDSA-L5. The imaging and flow cytometry experiments demonstrate that the NDSA-L5 probe can rapidly accumulate in the subcutaneous HCC cells and liver tumor tissue and shows a potential application in early detection and surgical navigation for HCC cancer.

Circumsporozoite Protein of Plasmodium berghei- and George Baker Virus A-Derived Peptides Trigger Efficient Cell Internalization of Bioconjugates and Functionalized Poly(ethylene glycol)-b-poly(benzyl malate)-Based Nanoparticles in Human Hepatoma Cells

In order to identify the peptides, selected from the literature, that exhibit the strongest tropism towards human hepatoma cells, cell uptake assays were performed using biotinylated synthetic peptides bound to fluorescent streptavidin or engrafted onto nanoparticles (NPs), prepared from biotin-poly(ethylene glycol)-block-poly(benzyl malate) (Biot-PEG-b-PMLABe) via streptavidin bridging. Two peptides, derived from the circumsporozoite protein of Plasmodium berghei- (CPB) and George Baker (GB) Virus A (GBVA10-9), strongly enhanced the endocytosis of both streptavidin conjugates and NPs in hepatoma cells, compared to primary human hepatocytes and non-hepatic cells. Unexpectedly, the uptake of CPB- and GBVA10-9 functionalized PEG-b-PMLABe-based NPs by hepatoma cells involved, at least in part, the peptide binding to apolipoproteins, which would promote NP’s interactions with cell membrane receptors of HDL particles. In addition, CPB and GBVA10-9 peptide–streptavidin conjugates favored the uptake by hepatoma cells over that of the human macrophages, known to strongly internalize nanoparticles by phagocytosis. These two peptides are promising candidate ligands for targeting hepatocellular carcinomas.

NIR-II imaging of hepatocellular carcinoma based on a humanized anti-GPC3 antibody

Liver cancer, of which hepatocellular carcinoma (HCC) is the most common form, is one of the most lethal cancers worldwide. The five-year survival rate for HCC is below 9%, which can be attributed to late diagnosis and limited treatment options at the late stage. Therefore, safe and efficient imaging strategies are urgently needed to facilitate HCC diagnosis and stage evaluation. The development of the second near infrared window (NIR-II, 1000-1700 nm) fluorescence imaging offers the advantages of enhanced resolutions, deeper penetration depth, and less autofluorescence compared to traditional NIR-I window (700-900 nm) imaging. Herein, an HCC targeted NIR-II fluorescent probe, GPC-ICG, was developed by labelling a humanized anti-GPC3 monoclonal antibody with indocyanine green (ICG). Compared to the negative control IgG-ICG probe, the GPC3-ICG probe demonstrated specific GPC3 targeting capability in vitro. And for GPC3 positive Huh-7 tumor bearing mice, the GPC3-ICG probe specifically accumulated in subcutaneous xenografts, with a tumor-background ratio (TBR) of up to 3. The NIR-II imaging of mice organs ex vivo also indicated that GPC3-ICG specifically targeted Huh-7 tumor tissue. Overall, GPC3-ICG is a promising NIR-II probe for GPC3 targeted imaging of HCC.

Multi-Modal Imaging Probe for Glypican-3 Overexpressed in Orthotopic Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is rising steadily in incidence, and more effective methods are needed for early detection and image-guided surgery. Glypican-3 (GPC3) is a cell surface biomarker that is overexpressed in early-stage cancer but not in cirrhosis. An IRDye800-labeled 12-mer amino acid sequence was identified, and specific binding to GPC3 was validated in vitro and in orthotopically implanted HCC tumors in vivo. Over 4-fold greater binding affinity and 2-fold faster kinetics were measured by comparison with previous GPC3 peptides. Photoacoustic images showed peak tumor uptake at 1.5 h post-injection and clearance within ∼24 h. Laparoscopic and whole-body fluorescence images showed strong intensity from tumor versus adjacent liver with about a 2-fold increase. Immunofluorescence staining of human liver specimens demonstrated specific binding to HCC versus cirrhosis with 79% sensitivity and 79% specificity, and normal liver with 81% sensitivity and 84% specificity. The near-infrared peptide is promising for early HCC detection in clinical trials.

Radiofluorinated GPC3-Binding Peptides for PET Imaging of Hepatocellular Carcinoma

PURPOSE

Hepatocellular carcinoma (HCC) remains one of the most challenging diseases worldwide. Glypican-3 (GPC-3) is a cell surface proteoglycan that is overexpressed on the membrane of HCC cells. The purpose of this study was to develop a target-specific radiofluorinated peptide for positron emission tomography (PET) imaging of GPC3 expression in hepatocellular carcinoma.

PROCEDURES

New GPC3-binding peptides (GP2076 and GP2633) were radiolabeled with F-18 using Al[¹⁸F]F labeling approach, and the resulting PET probes were subsequently subject to biological evaluations. A highly hydrophilic linker was incorporated into GP2633 with an aim of reducing the probe uptake in liver and increasing tumor-to-liver (T/L) contrast. Both GP2076 and GP2633 were radiolabeled using Al[¹⁸F]F chelation approach. The binding affinity, octanol/water partition coefficient, cellular uptake and efflux, and stability of both F-18 labeled peptides were tested. Tumor targeting efficacy and biodistribution of Al[¹⁸F]F-GP2076 and Al[¹⁸F]F-GP2633 were determined by PET imaging in HCC-bearing mice. Immunohistochemistry analyses were performed to compare the findings from PET scans.

RESULTS

Al[¹⁸F]F-GP2076 and Al[¹⁸F]F-GP2633 were rapidly radiosynthesized within 20 min in excellent radiochemical purity (> 97 %). Al[¹⁸F]F-GP2633 was determined to be more hydrophilic than Al[¹⁸F]F-GP2076 in terms of octanol/water partition coefficient. Both Al[¹⁸F]F-GP2076 and Al[¹⁸F]F-GP2633 demonstrated good in vitro and in vivo stability and binding specificity to GPC3-positive HepG2 cells. For PET imaging, Al[¹⁸F]F-GP2633 exhibited enhanced uptake in HepG2 tumor (%ID/g 3.37 ± 0.35 vs. 2.13 ± 0.55, P = 0.031) and reduced accumulation in liver (%ID/g 1.70 ± 0.26 vs. 3.70 ± 0.98, P = 0.027) at 60 min post-injection (pi) as compared to Al[¹⁸F]F-GP2076, resulting in significantly improved tumor-to-liver (T/L) contrast (ratio 2.00 ± 0.18 vs. 0.59 ± 0.14, P = 0.0004). Higher uptake of Al[¹⁸F]F-GP2633 in GPC3-positive HepG2 tumor was observed as compared to GPC3-negative McA-RH7777 tumor (%ID/g 3.37 ± 0.35 vs. 1.64 ± 0.03, P = 0.001) at 60 min pi, confirming GPC3-specific accumulation of Al[¹⁸F]F-GP2633 in HepG2 tumor.

CONCLUSION

The results demonstrated that Al[¹⁸F]F-GP2633 is a promising probe for PET imaging of GPC3 expression in HCC. Convenient preparation, excellent GPC3 specificity in HCC, and favorable excretion profile of Al[¹⁸F]F-GP2633 warrant further investigation for clinical translation. PET imaging with a GPC3-specific probe would provide clinicians with vital diagnostic information that could have a significant impact on the management of HCC patients.

Sorafenib encapsulated in nanocarrier functionalized with glypican-3 specific peptide for targeted therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world with increasing incidence. Chemotherapy is required for HCC patients after receiving surgical resection. Serious off-target induced side effects and systemic toxicity limit the clinical utility of drugs. Targeting therapeutic nanomedicine is an innovative strategy for enhancing drug delivery efficiency and reducing side effects. Here, we successfully formulated nanocarriers to encapsulate sorafenib, an FDA approved drug for treatment of HCC. Sorafenib is encapsulated with an entrapment efficiency >80% over 20 days. The effective aqueous solubility is improved over 1900-fold. The release ratio in vitro is characterized by a half-life of T_1/2 = 22.7 h. The peak target-to-background ratio for nanocarrier uptake by tumor occurs at 24 h post-injection, and is significantly greater for the target peptide versus controls. Ex vivo biodistribution confirms the in vivo results. Tumor regression is significantly greater for the target peptide versus controls after 21 days of therapy. No acute toxicity is found by blood chemistry or necropsy. In summary, a peptide specific for GPC3 has been identified, and used to modify the surface of a nanocarrier that encapsulates sorafenib with high entrapment efficiency. Regression of HCC xenograft tumors showed promise for targeted drug delivery.

In Vitro Performance of Published Glypican 3-Targeting Peptides TJ12P1 and L5 Indicates Lack of Specificity and Potency

Background: Glypican 3 (GPC3), a plasma membrane heparan sulfate proteoglycan, is overexpressed on human hepatocellular carcinoma and may represent a promising biomarker. Several studies have reported peptides that selectively bind to GPC3 and could serve as scaffolds for imaging or therapeutic agents.

Materials and Methods: We synthesized variants of two previously published peptides, DHLASLWWGTEL (TJ12P1) and RLNVGGTYFLTTRQ (L5), and evaluated their in vitro binding performance in paired isogenic cell lines, A431(GPC3⁻) and A431-GPC3⁺ (G1), as well as the liver cancer cell line HepG2. Using flow cytometry and biolayer interferometry (BLI), we compared the binding of the TJ12P1 and L5 peptide variants to the binding of corresponding scrambled peptides having the same amino acid composition, but in random sequence.

Results: While both peptides bound to G1 and HepG2, they also bound to A431. The corresponding scrambled peptides demonstrated greater apparent binding to both G1 and A431 than their specific counterparts. BLI confirmed lack of binding at 0.5–1 μM for both peptides.

Conclusions: We conclude that neither TJ12P1 nor L5 variant demonstrates selectivity for GPC3 at concentrations near the reported K_D, and that the peptides lack potency or are nonspecific, making them inadequate for use as imaging agents.

Promoting Early Diagnosis and Precise Therapy of Hepatocellular Carcinoma by Glypican-3-Targeted Synergistic Chemo-Photothermal Theranostics

The specific-targeting approach could promote the specificity of diagnosis and the accuracy of cancer treatment. The choice of a specific-targeting receptor is the key step in this approach. Glypican-3 (GPC3) is an oncofetal proteoglycan anchored on the cell membrane. It is overexpressed even in the early stage of hepatocellular carcinoma (HCC), whereas it shows almost no expression in the healthy adult liver. Therefore, GPC3 may be applied as a specific-targeting receptor for HCC theranostics. In this study, a GPC3 specific-targeting theranostics nanodevice, GPC3 targeting peptide (named G12)-modified liposomes co-loaded with sorafenib (SF) and IR780 iodide (IR780), was developed (GSI-Lip), which aims to realize early diagnosis and precise chemo-photothermal therapy of HCC. SF was the first-line chemotherapy drug for the treatment of HCC. IR780 was used for photothermal therapy and near-infrared fluorescence imaging. The evaluation of early diagnosis verified that early-stage tumors (3.45 ± 0.98 mm³, 2 days after 5 × 10⁵ H22 cells' inoculation in mice) could be clearly detected using GSI-Lip, which was significantly more sensitive than folic acid-modified liposomes ( p < 0.01, 32.90 ± 10.01 mm³, 4 days after 1 × 10⁶ H22 cells' inoculation in mice). The study of the endocytic pathway indicated that specific G12/GPC3 recognition may induce caveolae-mediated endocytosis of GSI-Lip. Notably, the accumulation of GSI-Lip in tumors was significantly increased compared with that observed with folic acid-modified liposomes ( p < 0.01). Specific-targeting endowed the precise antitumor effect of GSI-Lip. GSI-Lip showed a higher antitumor efficacy in comparison with folic acid-modified liposomes (inhibition rate: 90.52% vs 84.22%, respectively; p < 0.01). During a period of 21 days, the synergistic chemo-photothermal therapy (GSI-Lip + laser) exhibited a better antitumor effect versus GSI-Lip without laser (inhibition rate: 94.93% vs 90.52%, respectively; p < 0.01). Overall, GPC3-targeted GSI-Lip promoted the sensitivity and specificity of HCC early diagnosis and achieved synergistic efficacy of chemo-photothermal theranostics, which has potential clinical applications. Furthermore, the present study revealed that a more specific-targeting ligand could further improve the efficacy of theranostics against HCC.

An innovative peptide with high affinity to GPC3 for hepatocellular carcinoma diagnosis

Glypican-3 (GPC3) is a key biomarker for early diagnosis of human hepatocellular carcinoma (HCC) due to its overexpression in most HCC tumor tissues. Recently, peptides with high affinity to GPC3 have attracted more attention because of their high biocompatibility, non-immunogenicity, fast clearing and easy modification. Herein, we have designed an innovative GPC3 targeting peptide (sequence: DYEMHLWWGTEL, denoted as IPA) by using structure-based virtual simulation. The higher binding abilities of IPA over the reported peptide (YP) were displayed on different cell lines, showing a positive correlation with GPC3 expressions, which were further verified by the GPC3 protein binding assay. The GPC3 targeting specificity of IPA was proved by peptide blocking and siRNA experiment. The localized anchor of peptide IPA on the cell membranes of HepG2 and Huh-7 with GPC3 overexpression confirmed the GPC3 binding capacity. By connecting a near-infrared dye MPA, the in vivo identification ability of IPA to GPC3 was also demonstrated on GPC3-positive (HepG2) and GPC3-negative (U87) xenograft-bearing mice. These results indicated that the designed IPA presented desirable GPC3 targeting ability, showing promising prospects in detecting the expression of GPC3 for HCC targeting imaging.

Detecting GPC3-Expressing Hepatocellular Carcinoma with L5 Peptide-Guided Pretargeting Approach: In Vitro and In Vivo MR Imaging Experiments

Objective

To investigate the potential of L5 peptide-guided pretargeting approach to identify GPC3-expressing hepatocellular carcinoma (HCC) using ultrasmall superparamagnetic iron oxide (USPIO) as the MR probe.

Methods

Immunofluorescence with carboxyfluorescein- (FAM-) labeled L5 peptide was performed in HepG2 cells. Polyethylene glycol-modified USPIO (PEG-USPIO) and its conjugation with streptavidin (SA-PEG-USPIO) were synthesized, and their hydrodynamic diameters, zeta potential, T₂ relaxivity, and cytotoxicity were measured. In vitro and in vivo two-step pretargeting MR imaging was performed on HepG2 cells and tumor-bearing mice after the administration of biotinylated L5 peptide (first step), followed by SA-PEG-USPIO (second step). Prussian blue staining was performed to assess iron deposition in tumors.

Results

The high specificity of L5 peptide for GPC3 was demonstrated. Generation of SA-PEG-USPIO nanoparticles with good biocompatibility (an average hydrodynamic diameter of 35.97 nm and a zeta potential of -7.91 mV), superparamagnetism (R ₂ = 0.1039 × 10³ mM^-1s^-1), and low toxicity was achieved. The pretargeting group showed more enhancement than the nonpretargeting group both in vitro (60% vs 20%, P < 0.05) and in vivo (32% vs 6%, P < 0.001). Substantial iron deposition was only observed in HepG2 cells and tumors in the pretargeting group.

Conclusion

L5 peptide-guided, two-step pretargeting approach with USPIO as the MR imaging probe is a lucrative strategy to specifically identify GPC3-expressing HCC.

Glypican-3-targeted precision diagnosis of hepatocellular carcinoma on clinical sections with a supramolecular 2D imaging probe

The ability of chemical tools to effectively detect malignancy in frozen sections removed from patients during surgery is important for the timely determination of the subsequent surgical program. However, current clinical methods for tissue imaging rely on dye-based staining or antibody-based techniques, which are sluggish and complicated. Methods: Here, we have developed a 2D material-based supramolecular imaging probe for the simple, rapid yet precise diagnosis of hepatocellular carcinoma (HCC). The 2D probe is constructed through supramolecular self-assembly between a water soluble, fluorescent peptide ligand that selectively targets glypican-3 (GPC-3, a specific cell-surface biomarker for HCC) and 2D molybdenum disulfide that acts as a fluorescence quencher as well as imaging enhancer. Results: We show that the 2D imaging probe developed with minimal background fluorescence can sensitively and selectively image cells overexpressing GPC-3 over a range of control cells expressing other membrane proteins. Importantly, we demonstrate that the 2D probe is capable of rapidly (signal became readable within 1 min) imaging HCC tissues over para-carcinoma regions in frozen sections derived from HCC patients; the results are in accordance with those obtained using traditional clinical staining methods. Conclusion: Compared to conventional staining methods, which are laborious (e.g., over 30 min is needed for antibody-based immunosorbent assays) and complex (e.g., diagnosis is based on discrimination of the nucleus morphology of cancer cells from that of normal cells), our probe, with its simplicity and quickness, might become a promising candidate for tumor-section staining as well as fluorescence imaging-guided surgery.

Imaging the expression of glypican-3 in hepatocellular carcinoma by PET

The glypican-3 (GPC3) receptor is overexpressed in hepatocellular carcinoma (HCC) and is a potential diagnostic and therapeutic target. GPC3-targeted molecular imaging will be helpful to differentiate diagnosis and guide therapy. In the present study, we will develop a novel PET probe for imaging the expression of GPC-3. L5 (sequence: RLNVGGTYFLTTRQ), a GPC3 targeting peptide, was labeled with 5-carboxyfluorescein (FAM) and ¹⁸F-fluoride. Cell binding tests were performed to identify the binding specificity of FAM-L5 and ¹⁸F radiolabeled peptide. MicroPET/CT imaging was used to determine the potential of a novel PET tracer for visualizing HCC tumors with a high expression of GPC3. In vitro binding tests showed that the uptake of FAM-L5 in HepG2 cells (high expression of GPC3) was significantly higher than that of HL-7702 cells (negative expression of GPC3) (mean fluorescent intensity: 14,094 ± 797 vs. 2765 ± 314 events, t = 32.363, P = 0.000). Confocal fluorescent imaging identified that FAM-L5 accumulated where the GPC3 receptor was located. A novel PET tracer (¹⁸F-AlF-NODA-MP-6-Aoc-L5) was successfully labeled by chelation chemistry. In vitro cell uptake studies showed that ¹⁸F-AlF-NODA-MP-6-Aoc-L5 can bind to HepG2 tumor cells and was stable in PBS and mouse serum stability tests. MicroPET/CT showed that HepG2 tumors could be clearly visualized with a tumor/muscle ratio of 2.46 ± 0.53. However, the tumor/liver ratio was low (0.93 ± 0.16) due to the high physiological uptake in the liver. This study demonstrates that FAM and the ¹⁸F-labeled L5 peptide can selectively target HCC with a high expression of GPC3 in vitro and in vivo. ¹⁸F-AlF-NODA-MP-C6-L5 has the potential to be a GPC3 target tracer but requires some chemical modifications to achieve a high enough tumor/liver ratio for detection of the tumor in the liver.

Human Hepatocarcinoma Cell Targeting by Glypican-3 Ligand Peptide Functionalized Silica Nanoparticles: Implications for Ultrasound Molecular Imaging

Silica nanoparticles (SiNPs) are widely studied nanomaterials for their potential employment in advanced biomedical applications, such as selective molecular imaging and targeted drug delivery. SiNPs are generally low cost and highly biocompatible, can be easily functionalized with a wide variety of functional ligands, and have been demonstrated to be effective in enhancing ultrasound contrast at clinical diagnostic frequencies. Therefore, SiNPs might be used as contrast agents in echographic imaging. In this work, we have developed a SiNPs-based system for the in vitro molecular imaging of hepatocellular carcinoma cells that express high levels of glypican-3 protein (GPC-3) on their surface. In this regard, a novel GPC-3 targeting peptide was designed and conjugated to fluorescent silica nanoparticles. The physicochemical properties, acoustic behavior, and biocompatibility profile of the functionalized SiNPs were characterized; then binding and uptake of both naked and functionalized SiNPs were analyzed by laser scanning confocal microscopy and transmission electron microscopy in GPC-3 positive HepG2 cells, a human hepatocarcinoma cell line. The results obtained showed that GPC-3-functionalized fluorescent SiNPs significantly enhanced the ultrasound contrast and were effectively bound and taken up by HepG2 cells without affecting their viability.

Biology and function of glypican-3 as a candidate for early cancerous transformation of hepatocytes in hepatocellular carcinoma (Review)

Glypican-3 (GPC-3), a transmembrane heparan sulfate proteoglycan (HSPG), has recently been investigated as a player in tissue-dependent cellular signaling, specifically as a regulator of growth. Noteworthy, the regulatory protein has been implicated in both stimulatory and inhibitory pathways involving cell growth. Initially, GPC-3 was thought to act as a cell cycle regulator, as a loss-of-function mutation in the gene caused a hyper-proliferative state known as Simpson-Golabi-Behmel (SGB) overgrowth syndrome. Additionally, certain cancer types have displayed a downregulation of GPC-3 expression. More recently, the protein has been evaluated as a useful marker for hepatocellular carcinoma (HCC) due to its increased expression in the liver during times of growth. In contrast, the GPC-3 marker is not detectable in normal adult liver. Immunotherapy that targets GPC-3 and its affiliated proteins is under investigation as these new biomarkers may hold potential for the detection and treatment of HCC and other diseases in which GPC-3 may be overexpressed. Studies have reported that an overexpression of GPC-3 in HCC predicts a poorer prognosis. This prognostic value further pushes the question regarding GPC-3's role in the regulation and progression of HCC. This review will summarize the current knowledge regarding the clinical aspects of GPC-3, while also synthesizing the current literature with the aim to better understand this molecule's biological interactions at a molecular level, not only in the liver, but in the rest of the body as well. Due to the existing gap in the literature surrounding GPC-3, we believe further investigation of function, structure and domains, cellular localization, and other subfields is warranted to evaluate the protein as a whole, as well as its part in the study of HCC.

Current and Future Theranostic Applications of the Lipid-Calcium-Phosphate Nanoparticle Platform

Over the last four years, the Lipid-Calcium-Phosphate (LCP) nanoparticle platform has shown success in a wide range of treatment strategies, recently including theranostics. The high specific drug loading of radiometals into LCP, coupled with its ability to efficiently encapsulate many types of cytotoxic agents, allows a broad range of theranostic applications, many of which are yet unexplored. In addition to providing an overview of current medical imaging modalities, this review highlights the current theranostic applications for LCP using SPECT and PET, and discusses potential future uses of the platform by comparing it with both systemically and locally delivered clinical radiotherapy options as well as introducing its applications as an MRI contrast agent. Strengths and weaknesses of LCP and of nanoparticles in general are discussed, as well as caveats regarding the use of fluorescence to determine the accumulation or biodistribution of a probe.

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.

Echographic imaging of tumoral cells through novel nanosystems for image diagnosis

Since the recognition of disease molecular basis, it has become clear that the keystone moments of medical practice, namely early diagnosis, appropriate therapeutic treatment and patient follow-up, must be approached at a molecular level. These objectives will be in the near future more effectively achievable thanks to the impressive developments in nanotechnologies and their applications to the biomedical field, starting-up the nanomedicine era. The continuous advances in the development of biocompatible smart nanomaterials, in particular, will be crucial in several aspects of medicine. In fact, the possibility of manufacturing nanoparticle contrast agents that can be selectively targeted to specific pathological cells has extended molecular imaging applications to non-ionizing techniques and, at the same time, has made reachable the perspective of combining highly accurate diagnoses and personalized therapies in a single theranostic intervention. Main developing applications of nanosized theranostic agents include targeted molecular imaging, controlled drug release, therapeutic monitoring, guidance of radiation-based treatments and surgical interventions. Here we will review the most recent findings in nanoparticles contrast agents and their applications in the field of cancer molecular imaging employing non-ionizing techniques and disease-specific contrast agents, with special focus on recent findings on those nanomaterials particularly promising for ultrasound molecular imaging and simultaneous treatment of cancer.

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.

Expression characteristics and diagnostic value of annexin A2 in hepatocellular carcinoma

AIM: To investigate the characteristics and diagnostic value of annexin A2 (ANXA2) expression in cancerous tissues and sera of patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

METHODS: Levels of liver ANXA2 gene transcription or protein expression were analyzed in HCC-, their self-controlled precancerous-, and distant cancerous- tissues from 30 HCC. Serum levels of ANXA2 expression in 115 patients with HCC, 25 with metastatic liver cancer, 35 with chronic hepatitis, 28 with acute hepatitis, 38 with cirrhosis, and 30 healthy controls were determined. Clinicopathological characteristics of circulating ANXA2 expression were analyzed, and its diagnostic efficiency and clinical values in HCC were evaluated.

RESULTS: ANXA2 expression was localized in both cell membrane and cytoplasm in HCC tissue, mainly in the cytoplasm of matched adjacent cancerous tissue, and there was almost no positive staining in matched distant cancerous tissue. Abnormal expression of liver ANXA2 was present in HCC tissues compared with self-controlled adjacent- and distant-cancerous tissues at protein or mRNA level. Circulating ANXA2 in HCC patients was significantly higher than that of other liver diseases (P < 0.01) except metastatic liver cancer. If the diagnostic cutoff value of ANXA2 level was more than 18 ng/mL, the incidence of serum ANXA2 was 86.96% in the HCC group, 80% in the metastatic liver cancer group, 31.58% in the liver cirrhosis group, none in the chronic hepatitis or acute hepatitis or normal control group, respectively. Serum ANXA2 expression in HCC patients was correlated with HBV infection (27.38 ± 5.67 ng/mL vs 18.58 ± 7.83 ng/mL, P < 0.01), extrahepatic metastasis (26.11 ± 5.43 ng/mL vs 22.79 ± 5.64 ng/mL, P < 0.01), and portal vein thrombus (26.03 ± 5.99 ng/mL vs 23.06 ± 5.03 ng/mL, P < 0.01), and was significantly higher (P < 0.01) in the moderately- (26.19 ± 5.34 ng/mL) or the poorly- differentiated group (27.05 ± 5.13 ng/mL) than in the well differentiated group (20.43 ± 4.97 ng/mL), and in the tumor node metastasis stages III-IV (P < 0.01) than in stages I-II. ANXA2 was not correlated with patient sex, age, size or α-fetoprotein (AFP) level. Area under the receiver operating characteristic curve for the whole range of sensitivities and specificities was 0.796 for ANXA2 and 0.782 for AFP. Combining detection of serum ANXA2 and AFP substantially improved the diagnostic efficiency (96.52%) and the negative predictive value (96.61%) for HCC.

CONCLUSION: The characteristics and distribution of ANXA2 expression has good diagnostic potential for HCC diagnosis.