Dinutuximab: A Review in High-Risk Neuroblastoma

Cost-effectiveness analysis of dinutuximab β for the treatment of high-risk neuroblastoma in China

BACKGROUND

Dinutuximab β can be used to treat children with high-risk neuroblastoma (NB). Due to its high price, whether dinutuximab β is cost-effective for the treatment of high-risk NB remains uncertain. Therefore, assessing the cost-effectiveness of dinutuximab β in children with high-risk NB is of high importance.

METHODS

The health utilities and economic outcomes in children with high-risk NB were projected using a partitioned survival model. The individual patient data (IPD) of add-on treatment with dinutuximab β (GD2 group) were derived from the literature, while the IPD of traditional therapy (TT group) were obtained from retrospective data of Shanghai Children's Medical Center. Treatment costs included drugs, adverse event-related expenses, and medical resource use. Utility values were obtained from the literature. Costs and quality-adjusted life-years (QALYs) were measured over a 10-year time horizon. Deterministic sensitivity analyses (DSA) and probabilistic sensitivity analyses (PSA) were also conducted.

RESULTS

Compared with the TT group, QALY increased in the GD2 group by 0.72 with an increased cost of $171,269.70, leading to an incremental cost-effectiveness ratio of 236,462.75$/QALY. DSA showed that the price of dinutuximab β was the main factor on the results than other parameters. Compared with the TT group, the GD2 group could not be cost-effective in the PSA at the $37,920/QALY threshold.

CONCLUSION

Results found that dinutuximab β is not a cost-effective treatment option for children with high-risk NB unless its price is significantly reduced.

Therapeutic Antibodies in Medicine

Antibody engineering has developed into a wide-reaching field, impacting a multitude of industries, most notably healthcare and diagnostics. The seminal work on developing the first monoclonal antibody four decades ago has witnessed exponential growth in the last 10-15 years, where regulators have approved monoclonal antibodies as therapeutics and for several diagnostic applications, including the remarkable attention it garnered during the pandemic. In recent years, antibodies have become the fastest-growing class of biological drugs approved for the treatment of a wide range of diseases, from cancer to autoimmune conditions. This review discusses the field of therapeutic antibodies as it stands today. It summarizes and outlines the clinical relevance and application of therapeutic antibodies in treating a landscape of diseases in different disciplines of medicine. It discusses the nomenclature, various approaches to antibody therapies, and the evolution of antibody therapeutics. It also discusses the risk profile and adverse immune reactions associated with the antibodies and sheds light on future applications and perspectives in antibody drug discovery.

Antibody engineering and its therapeutic applications

As a natural function, antibodies defend the host from infected cells and pathogens by recognizing their pathogenic determinants. Antibodies (Abs) gained wide acceptance with an enormous impact on human health and have predominantly captured the arena of bio-therapeutics and bio-diagnostics. The scope of Ab-based biologics is vast, and it is likely to solve many unmet clinical needs in future. The majority of attention is now devoted to developing innovative technologies for manufacturing and engineering Abs, better suited to satisfy human needs. The advent of Ab engineering technologies (AET) led to phenomenal developments leading to the generation of Abs-/Ab-derived molecules with desirable functional properties proportional to their expanding requirements. Evolution brought by AET, from the naturally occurring Ab forms to several advanced Ab formats and derivatives, was much needed as it is of great interest to the pharmaceutical industry. Thus, numerous advancements in AET have propelled success in therapeutic Ab development, along with the potential for ever-increasing improvements. Unique characteristics of Abs, such as its diversity, specificity, structural integrity and an array of possible applications, together inspire continuous innovation in the field. Overall, the AET could assist in conquer of several limitations of Abs in terms of their applicability in the field of therapeutics, diagnostics and research; AET has so far led to the production of next-generation Abs, which have revolutionized these arenas. Here in this review, we discuss the various distinguished engineering platforms for Ab development and the progress in modern therapeutics by the so-called "next-generation Abs."

Recent Evidence-Based Clinical Guide for the Use of Dinutuximab Beta in Pediatric Patients with Neuroblastoma

The anti-GD2 antibody dinutuximab beta (Qarziba^®) has been added to the present standard of care for patients with high-risk neuroblastoma in Europe based on the positive results obtained in different studies. In both the first-line and relapsed/refractory settings, treatment with dinutuximab beta attains objective clinical responses in children with high-risk neuroblastoma. Its incorporation has changed the outcome for these patients and optimized management should be guaranteed to minimize possible adverse effects. Most prevalent adverse events include pain, allergic reactions, fever and capillary leak syndrome. There are still no evidence-based clinical guidelines that include the latest published evidence to optimize its use, as it depends on the experience gained in each referral center. Topics such as the mode of preparation and administration, the concomitant use of interleukin-2, the recommended pediatric age and dose for its use, or the adequate management of possible toxicities are important aspects to review. The objective of this article was to update the clinical guide to management with dinutuximab beta of children with neuroblastoma based on the most recent published evidence and our own experience in clinical practice.

GD2 Expression in Medulloblastoma and Neuroblastoma for Personalized Immunotherapy: A Matter of Subtype

Neuroblastoma (NBL) and medulloblastoma (MB) are aggressive pediatric cancers which can benefit from therapies targeting gangliosides. Therefore, we compared the ganglioside profile of 9 MB and 14 NBL samples by thin layer chromatography and mass spectrometry. NBL had the highest expression of GD2 (median 0.54 nmol GD2/mg protein), and also expressed complex gangliosides. GD2-low samples expressed GD1a and were more differentiated. MB mainly expressed GD2 (median 0.032 nmol GD2/mg protein) or GM3. Four sonic hedgehog-activated (SHH) as well as one group 4 and one group 3 MBs were GD2-positive. Two group 3 MB samples were GD2-negative but GM3-positive. N-glycolyl neuraminic acid-containing GM3 was neither detected in NBL nor MB by mass spectrometry. Furthermore, a GD2-phenotype predicting two-gene signature (ST8SIA1 and B4GALNT1) was applied to RNA-Seq datasets, including 86 MBs and validated by qRT-PCR. The signature values were decreased in group 3 and wingless-activated (WNT) compared to SHH and group 4 MBs. These results suggest that while NBL is GD2-positive, only some MB patients can benefit from a GD2-directed therapy. The expression of genes involved in the ganglioside synthesis may allow the identification of GD2-positive MBs. Finally, the ganglioside profile may reflect the differentiation status in NBL and could help to define MB subtypes.

Stem Cell-Based Models for Studying the Effects of Cancer and Cancer Therapies on the Peripheral Nervous System

In recent years, the complexity of cancer and cancer therapies and their interactions with the peripheral nervous system have come into focus, but limitations in experimental models have remained a significant challenge in the field. As evidence, there are currently no therapies approved that target cancer-peripheral nervous system or cancer therapy-peripheral nervous system interactions as an anti-neoplastic or anti-neurotoxic agent, respectively. Human pluripotent stem cells offer an appealing model system that, unlike rodent models, is compatible with high throughput, high content applications; techniques that reflect modern drug discovery methodologies. Thus, utilizing the key advantages of stem cell-based models in tandem with the strengths of traditional animal models offers a complementary and interdisciplinary strategy to advance cancer and cancer therapy-peripheral nervous system research and drug discovery. In this review, the current status of the cancer-peripheral nervous system and cancer therapy-peripheral nervous system research is discussed, examples where stem cell-based models have been implemented are described, and avenues where stem cell-based models may further advance the field are proposed.

Bi-specific and Tri-specific NK Cell Engagers: The New Avenue of Targeted NK Cell Immunotherapy

Natural killer (NK) cell-mediated cancer immunotherapy has grown significantly over the past two decades. More recently, multi-specific engagers have been developed as cancer therapeutics to effectively arm endogenous NK cells to more potently induce specific cytolytic responses against tumor targets. This review explores the bi- and tri-specific NK/tumor engagers that are emerging as a new generation of immunotherapeutics. These molecules vary in configuration, but they typically have small molecular weights and domains that engage specific tumor antigens and NK cell-activating receptors such as CD16, NKp30, NKp46, and NKG2D. They have demonstrated compelling potential in boosting NK cell cytotoxicity against specific tumor targets. This highly adaptable off-the-shelf platform, which in some formats also integrates cytokines, is poised to revolutionize targeted NK cell immunotherapy, either as a monotherapy or in combination with other effective anti-cancer therapies.

The Current Status and Future Potential of Theranostics to Diagnose and Treat Childhood Cancer

In theranostics (i.e., therapy and diagnostics) radiopharmaceuticals are used for both therapeutic and diagnostic purposes by targeting one specific tumor receptor. Biologically relevant compounds, e.g., receptor ligands or drugs, are labeled with radionuclides to form radiopharmaceuticals. The possible applications are multifold: visualization of biological processes or tumor biology in vivo, diagnosis and tumor staging, therapy planning, and treatment of specific tumors. Theranostics research is multidisciplinary and allows for the rapid translation of potential tumor targets from preclinical research to “first-in-man” clinical studies. In the last decade, the use of theranostics has seen an unprecedented value for adult cancer patients. Several radiopharmaceuticals are routinely used in clinical practice (e.g., [⁶⁸Ga/¹⁷⁷Lu]DOTATATE), and dozens are under (pre)clinical development. In contrast to these successes in adult oncology, theranostics have scarcely been developed to diagnose and treat pediatric cancers. To date, [^123/131I]meta-iodobenzylguanidine ([^123/131I]mIBG) is the only available and approved theranostic in pediatric oncology. mIBG targets the norepinephrine transporter, expressed by neuroblastoma tumors. For most pediatric tumors, including neuroblastoma, there is a clear need for novel and improved radiopharmaceuticals for imaging and therapy. The strategy of theranostics for pediatric oncology can be divided in (1) the improvement of existing theranostics, (2) the translation of theranostics developed in adult oncology for pediatric purposes, and (3) the development of novel theranostics for pediatric tumor-specific targets. Here, we describe the recent advances in theranostics development in pediatric oncology and shed a light on how this methodology can affect diagnosis and provide additional treatment options for these patients.

Development of a dinutuximab delivery system using silk foams for GD2 targeted neuroblastoma cell death

Neuroblastoma is the most common extracranial solid tumor of childhood and is associated with poor survival in high risk patients. Recently, dinutuximab (DNX) has emerged as an effective immunotherapy to treat patients with high risk neuroblastoma. DNX works through the induction of cell lysis via complement-dependent cytotoxicity (CDC) or antibody dependent cellular cytotoxicity (ADCC). However, one third of patients who undergo DNX treatment exhibit tumor relapse and the therapy is dose limited by side effects such as severe pain. To overcome delivery challenges of DNX, including large size and dose limiting side effects, we fabricated a delivery system capable of sustained local delivery of bioactive DNX utilizing silk fibroin. We evaluated the impact of silk properties (MW, crystallinity, and concentration) on release properties and confirmed the bioactivity of the release product. Additionally, we observed that the effectiveness of CDC induction by DNX could be correlated to the GD2 expression level of the target cells, with both the intravenous DNX formulation and the released DNX. Collectively, these data highlights a strategy to overcome delivery challenges and potentially improve therapeutic efficacy in cells expressing heterogenous levels of GD2.

Histone Deacetylases and Histone Deacetylase Inhibitors in Neuroblastoma

Histone deacetylases (HDACs) are enzymes that play a key role in regulating gene expression by remodeling chromatin structure. An imbalance of histone acetylation caused by deregulated HDAC expression and activity is known to promote tumor progression in a number of tumor types, including neuroblastoma, the most common solid tumor in children. Consequently, the inhibition of HDACs has emerged as a potential strategy to reverse these aberrant epigenetic changes, and several classes of HDAC inhibitors (HDACi) have been shown to inhibit tumor proliferation, or induce differentiation, apoptosis and cell cycle arrest in neuroblastoma. Further, the combined use of HDACi with other chemotherapy agents, or radiotherapy, has shown promising pre-clinical results and various HDACi have progressed to different stages in clinical trials. Despite this, the effects of HDACi are multifaceted and more work needs to be done to unravel their specific mechanisms of actions. In this review, we discuss the functional role of HDACs in neuroblastoma and the potential of HDACi to be optimized for development and use in the clinic for treatment of patients with neuroblastoma.

Local delivery of dinutuximab from lyophilized silk fibroin foams for treatment of an orthotopic neuroblastoma model

Immunotherapy targeting GD2 is a primary treatment for patients with high-risk neuroblastoma. Dinutuximab is a monoclonal antibody with great clinical promise but is limited by side effects such as severe pain. Local delivery has emerged as a potential mechanism to deliver higher doses of therapeutics into the tumor bed, while limiting systemic toxicity. We aim to deliver dinutuximab locally in a lyophilized silk fibroin foam for the treatment of an orthotopic neuroblastoma mouse model. Dinutuximab-loaded silk fibroin foams were fabricated through lyophilization. In vitro release profile and bioactivity of the release through complement-dependent cytotoxicity were characterized. MYCN-amplified neuroblastoma cells (KELLY) were injected into the left gland of mice to generate an orthotopic neuroblastoma model. Once the tumor volume reached 100 mm³ , dinutuximab-, human IgG-, or buffer-loaded foams were implanted into the tumor and growth was monitored using high-resolution ultrasound. Post-resection histology was performed on tumors. Dinutuximab-loaded silk fibroin foams exhibited a burst release, with slow release thereafter in vitro with maintenance of bioactivity. The dinutuximab-loaded foam significantly inhibited xenograft tumor growth compared to IgG- and buffer-loaded foams. Histological analysis revealed the presence of dinutuximab within the tumor and neutrophils and macrophages infiltrating into dinutuximab-loaded silk foam. Tumors treated with local dinutuximab had decreased MYCN expression on histology compared to control or IgG-treated tumors. Silk fibroin foams offer a mechanism for local release of dinutuximab within the neuroblastoma tumor. This local delivery achieved a significant decrease in tumor growth rate in a mouse orthotopic tumor model.

Repurposing a psychoactive drug for children with cancer: p27Kip1-dependent inhibition of metastatic neuroblastomas by Prozac

The MYC family of transcription factors is a major driver of human cancer and potential therapeutic target. However, no clinically viable drugs have been yet developed that are able to directly tackle MYC oncoproteins. In our laboratory, we are exploring alternative approaches aiming to disturb signalling downstream of MYC. MYCN is frequently activated in neuroblastoma, a paediatric solid malignancy that, in its metastatic form, has a very poor prognosis. An important pathway regulated by MYC is the CKS1/SKP2/p27^kip1 axis. In this study, we have repurposed the anti-psychotic drug Prozac to disrupt CKS1/SKP2/p27^Kip1 signalling and assess its potential as an anti-neuroblastoma agent in vitro and in vivo. Using DNA editing technology, we show that stabilisation of p27^Kip1 operated by Prozac in MYC-activated cells is essential for the anti-neuroblastoma activity of the drug. Furthermore, dosing mice with a concentration of Prozac equivalent to that used in long-term clinical trials in children with psychiatric disorders caused a significant reduction of metastatic disease in two models of high-risk neuroblastoma. The favourable toxicity profile of Prozac suggests that long-term treatments might be implemented in children with MYC/CKS1^high neuroblastomas.

Immunotherapies for pediatric cancer: current landscape and future perspectives

The advent of immunotherapy has revolutionized how we manage and treat cancer. While the majority of immunotherapy-related studies performed to date have focused on adult malignancies, a handful of these therapies have also recently found success within the pediatric space. In this review, we examine the immunotherapeutic agents that have achieved the approval of the US Food and Drug Administration for treating childhood cancers, highlighting their development, mechanisms of action, and the lessons learned from the seminal clinical trials that ultimately led to their approval. We also shine a spotlight on several emerging immunotherapeutic modalities that we believe are poised to have a positive impact on the treatment of pediatric malignancies in the near future.

Challenges and Opportunities for Childhood Cancer Drug Development

Cancer in children is rare with approximately 15,700 new cases diagnosed in the United States annually. Through use of multimodality therapy (surgery, radiation therapy, and aggressive chemotherapy), 70% of patients will be "cured" of their disease, and 5-year event-free survival exceeds 80%. However, for patients surviving their malignancy, therapy-related long-term adverse effects are severe, with an estimated 50% having chronic life-threatening toxicities related to therapy in their fourth or fifth decade of life. While overall intensive therapy with cytotoxic agents continues to reduce cancer-related mortality, new understanding of the molecular etiology of many childhood cancers offers an opportunity to redirect efforts to develop effective, less genotoxic therapeutic options, including agents that target oncogenic drivers directly, and the potential for use of agents that target the tumor microenvironment and immune-directed therapies. However, for many high-risk cancers, significant challenges remain.

Anti-GD2 antibody-containing immunotherapy postconsolidation therapy for people with high-risk neuroblastoma treated with autologous haematopoietic stem cell transplantation

BACKGROUND

Neuroblastoma is a rare malignant disease that primarily affects children. The tumours mainly develop in the adrenal medullary tissue, and an abdominal mass is the most common presentation. High-risk disease is characterised by metastasis and other primary tumour characteristics resulting in increased risk for an adverse outcome. The GD2 carbohydrate antigen is expressed on the cell surface of neuroblastoma tumour cells and is thus a promising target for anti-GD2 antibody-containing immunotherapy.

OBJECTIVES

To assess the efficacy of anti-GD2 antibody-containing postconsolidation immunotherapy after high-dose chemotherapy (HDCT) and autologous haematopoietic stem cell transplantation (HSCT) compared to standard therapy after HDCT and autologous HSCT in people with high-risk neuroblastoma. Our primary outcomes were overall survival and treatment-related mortality. Our secondary outcomes were progression-free survival, event-free survival, early toxicity, late non-haematological toxicity, and health-related quality of life.

SEARCH METHODS

We searched the electronic databases CENTRAL (2018, Issue 9), MEDLINE (PubMed), and Embase (Ovid) on 20 September 2018. We searched trial registries and conference proceedings on 28 October 2018. Further searches included reference lists of recent reviews and relevant articles as well as contacting experts in the field. There were no limits on publication year or language.

SELECTION CRITERIA

Randomised controlled trials evaluating anti-GD2 antibody-containing immunotherapy after HDCT and autologous HSCT in people with high-risk neuroblastoma.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, abstracted data on study and participant characteristics, and assessed risk of bias and GRADE. Any differences were resolved by discussion, with third-party arbitration unnecessary. We performed analyses according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. We used the five GRADE considerations, that is study limitations, consistency of effect, imprecision, indirectness, and publication bias, to judge the quality of the evidence.

MAIN RESULTS

We identified one randomised controlled trial that included 226 people with high-risk neuroblastoma who were pre-treated with autologous HSCT. The study randomised 113 participants to receive immunotherapy including isotretinoin, granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-2, and ch14.18, a type of anti-GD2 antibody also known as dinutuximab. The study randomised another 113 participants to receive standard therapy including isotretinoin.The results on overall survival favoured the dinutuximab-containing immunotherapy group (hazard ratio (HR) 0.50, 95% confidence interval (CI) 0.31 to 0.80; P = 0.004). The results on event-free survival also favoured the dinutuximab-containing immunotherapy group (HR 0.61, 95% CI 0.41 to 0.92; P = 0.020). Randomised data on adverse events were not reported separately. The study did not report progression-free survival, late non-haematological toxicity, and health-related quality of life as separate endpoints. We graded the quality of the evidence as moderate.

AUTHORS' CONCLUSIONS

The evidence base favours dinutuximab-containing immunotherapy compared to standard therapy concerning overall survival and event-free survival in people with high-risk neuroblastoma pre-treated with autologous HSCT. Randomised data on adverse events are lacking, therefore more research is needed before definitive conclusions can be made regarding this outcome.

RDM1 promotes neuroblastoma growth through the RAS-Raf-MEK-ERK pathway

Neuroblastoma (NB) is an aggressive cancer that originates in the sympathetic nervous system and primarily affects children. Here, we show that high levels of RAD52 motif containing 1 (RDM1; a protein with similarities to RAD52, which is important for double-strand DNA repair) are associated with poor clinical outcomes for NB. In addition, RDM1^-/- cells exhibited increased sensitivity to cisplatin, a common chemotherapy drug, and disruption of RDM1 suppressed NB cell proliferation. We also report that loss of RDM1 augmented cell apoptosis and induced cell cycle arrest, and that stable knockdown of RDM1 significantly inhibited NB tumor growth in a xenograft mouse model. Importantly, we identified that RDM1 promoted cell proliferation via the RAS-Raf-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) signaling pathway. In conclusion, the current study demonstrates a correlation between DNA damage regulator RDM1 and the oncogenic RAS-Raf-MEK-ERK pathway in NB.

Ganglioside GD3 synthase (GD3S), a novel cancer drug target

Gangliosides are a class of important glycosphingolipids containing sialic acid that are widely distributed on the outer surface of cells and are abundantly distributed in brain tissue. Disialoganglioside with three glycosyl groups (GD3) and disialoganglioside with two glycosyl groups (GD2) are markedly increased in pathological conditions such as cancers and neurodegenerative diseases. GD3 and GD2 were found to play important roles in cancers by mediating cell proliferation, migration, invasion, adhesion, angiogenesis and in preventing immunosuppression of tumors. GD3 synthase (GD3S) is the regulatory enzyme of GD3 and GD2 synthesis, and is important in tumorigenesis and the development of cancers. The study of GD3S as a drug target may be of great significance for the discovery of new drugs for cancer treatment. This review will describe the gangliosides and their roles in physiological and pathological conditions; the roles of GD3 and GD2 in cancers; the expression, functions and mechanisms of GD3S, and its potential as a drug target in cancers.

S-trityl-L-cysteine, a novel Eg5 inhibitor, is a potent chemotherapeutic strategy in neuroblastoma

Eg5 is a member of the kinesin-5 family. It is involved in the formation of the bipolar spindle and serves a crucial role in mitosis; meaning that mitotic activation may serve as a chemotherapeutic strategy. However, the anticancer activity of Eg5 inhibitors in neuroblastoma remains uncharacterized. In the present study, the expression of Eg5 was examined in clinical tissue samples and neuroblastoma cell lines, SK-N-SH, SH-SY5Y and SK-N-BE2. Additionally, the antitumor activity of the Eg5 inhibitor, S-trityl-L-cysteine (STLC), was confirmed in vitro. STLC could mediate cell apoptosis, as well as cell cycle arrest, in a dose-dependent manner, which may contribute toward its antitumor activity. STLC-mediated apoptosis and cell cycle arrest were triggered by activation of the mitogen-activated protein kinase and nuclear factor kB signaling pathways. These results suggested that STLC may have potential in the in vivo treatment of neuroblastoma.

New Strategies Using Antibody Combinations to Increase Cancer Treatment Effectiveness

Antibodies have proven their high value in antitumor therapy over the last two decades. They are currently being used as the first-choice to treat some of the most frequent metastatic cancers, like HER2⁺ breast cancers or colorectal cancers, currently treated with trastuzumab (Herceptin) and bevacizumab (Avastin), respectively. The impressive therapeutic success of antibodies inhibiting immune checkpoints has extended the use of therapeutic antibodies to previously unanticipated tumor types. These anti-immune checkpoint antibodies allowed the cure of patients devoid of other therapeutic options, through the recovery of the patient’s own immune response against the tumor. In this review, we describe how the antibody-based therapies will evolve, including the use of antibodies in combinations, their main characteristics, advantages, and how they could contribute to significantly increase the chances of success in cancer therapy. Indeed, novel combinations will consist of mixtures of antibodies against either different epitopes of the same molecule or different targets on the same tumor cell; bispecific or multispecific antibodies able of simultaneously binding tumor cells, immune cells or extracellular molecules; immunomodulatory antibodies; antibody-based molecules, including fusion proteins between a ligand or a receptor domain and the IgG Fab or Fc fragments; autologous or heterologous cells; and different formats of vaccines. Through complementary mechanisms of action, these combinations could contribute to elude the current limitations of a single antibody which recognizes only one particular epitope. These combinations may allow the simultaneous attack of the cancer cells by using the help of the own immune cells and exerting wider therapeutic effects, based on a more specific, fast, and robust response, trying to mimic the action of the immune system.

Honokiol triggers receptor‑interacting protein kinase 3‑mediated cell death of neuroblastoma cells by upregulating reactive oxygen species

Neuroblastoma is the most common form of childhood extracranial tumor and almost half of neuroblastoma cases occur in infants under two years old. Neuroblastoma accounts for ~6‑10% of childhood cancers and 15% of cancer‑associated childhood mortality. However, an effective treatment remains to be developed. Honokiol exhibits long‑lasting central muscle relaxation, anti‑inflammatory, antibacterial, antimicrobial, antiulcer, antioxidation, antiaging and antitumor effects. Honokiol has been previously demonstrated to kill neuroblastoma cells, however, the underlying mechanism of action remains unclear. The present study reports that honokiol inhibits the growth of neuroblastoma cells via upregulation of reactive oxygen species (ROS). MTT assays demonstrated that treatment of Neuro‑2a neuroblastoma cells with honokiol resulted in time‑ and dose‑dependent inhibition of cell proliferation, which was associated with upregulation of the protein expression of receptor‑interacting protein kinase 3 (RIP3), as demonstrated by western blot analysis. Furthermore, knockdown of RIP3 by small interfering RNA, or pharmacological inhibition of RIP3 by the RIP3 specific inhibitor necrosulfonamide, reversed honokiol‑induced loss of cell viability in Neuro‑2a cells. Importantly, honokiol significantly increased the intracellular ROS levels as determined by a 2',7'‑dichlorofluorescin diacetate assay, while ROS scavenger N‑acetyl cysteine significantly prevented the induction of ROS and RIP3 by honokiol. The results of the present study indicate that honokiol may suppress the growth of neuroblastoma Neuro‑2a cells, at least partially, through ROS‑mediated upregulation of RIP3.

Therapeutic Antibodies: What Have We Learnt from Targeting CD20 and Where Are We Going?

Therapeutic monoclonal antibodies (mAbs) have become one of the fastest growing classes of drugs in recent years and are approved for the treatment of a wide range of indications, from cancer to autoimmune disease. Perhaps the best studied target is the pan B-cell marker CD20. Indeed, the first mAb to receive approval by the Food and Drug Administration for use in cancer treatment was the CD20-targeting mAb rituximab (Rituxan®). Since its approval for relapsed/refractory non-Hodgkin's lymphoma in 1997, rituximab has been licensed for use in the treatment of numerous other B-cell malignancies, as well as autoimmune conditions, including rheumatoid arthritis. Despite having a significant impact on the treatment of these patients, the exact mechanisms of action of rituximab remain incompletely understood. Nevertheless, numerous second- and third-generation anti-CD20 mAbs have since been developed using various strategies to enhance specific effector functions thought to be key for efficacy. A plethora of knowledge has been gained during the development and testing of these mAbs, and this knowledge can now be applied to the design of novel mAbs directed to targets beyond CD20. As we enter the "post-rituximab" era, this review will focus on the lessons learned thus far through investigation of anti-CD20 mAb. Also discussed are current and future developments relating to enhanced effector function, such as the ability to form multimers on the target cell surface. These strategies have potential applications not only in oncology but also in the improved treatment of autoimmune disorders and infectious diseases. Finally, potential approaches to overcoming mechanisms of resistance to anti-CD20 therapy are discussed, chiefly involving the combination of anti-CD20 mAbs with various other agents to resensitize patients to treatment.

Modulation of interactions of neuroblastoma cell lines with extracellular matrix proteins affects their sensitivity to treatment with the anti-GD2 ganglioside antibody 14G2a

Children diagnosed with high risk neuroblastoma have poor prognosis which stimulates efforts to broaden therapies of the neoplasm. GD2-ganglioside (GD2) marks neuroblastoma cells and is a target for monoclonal antibodies. We have recently shown that some neuroblastoma cell lines are sensitive to direct cytotoxicity of the anti-GD2 mouse monoclonal antibody 14G2a (mAb). For IMR-32 and LA-N-1 cell lines, treatment with the 14G2a mAb induced evident changes in appearance such as cell rounding, aggregation, loose contact with culture plastic, or detachment. Such findings prompted us to investigate whether modulation of attachment of neuroblastoma cells to extracellular matrix (ECM) proteins can affect their sensitivity to the 14G2a mAb treatment. First, using ultra-low attachment plates, we show that survival of the IMR-32, LA-N-1, LA-N-5, CHP-134 and Kelly cells depends on attachment. Next, we compared cellular ATP levels of the cell lines treated with the 14G2a mAb using uncoated, fibronectin-, collagen IV-coated surfaces to show that the ECM proteins slightly modulate sensitivity of the cell lines to the mAb. Then, we characterized presence of selected integrin subunits or their complexes on the cell surface. Finally, we applied small molecule inhibitors of selected integrin complexes: obtustatin (inhibiting α1β1 heterodimer), BIO 1211 (inhibiting active α4β1 heterodimer), cilengitide and SB273005 (inhibitors of αVβ3, αVβ5 heterodimers) to verify their effects on attachment of cell lines, cellular ATP levels, and in some experiments activities of apoptosis-executing caspase-3 and -7, for the compounds used alone or in combination with the 14G2a mAb. We characterized levels of total FAK (focal adhesion kinase), p-FAK (Tyr397) in IMR-32 cells treated with BIO 1211, and in LA-N-5, Kelly and SK-N-SH cells treated with SB273005. Our results extend knowledge on factors influencing cytotoxicity of 14G2a.

Antibody-dependent cell cytotoxicity: immunotherapy strategies enhancing effector NK cells

Antibody-dependent cellular cytotoxicity (ADCC) is a set of mechanisms that target cells coated with IgG antibodies of the proper subclasses (IgG1 in the human) to be the prey of cell-to-cell cytolysis executed by immune cells expressing FcRIIIA (CD16A). These effectors include not only natural killer (NK) cells but also other CD16⁺ subsets such as monocyte/macrophages, NKT cells or γδ T cells. In cancer therapy, ADCC is exploited by antibodies that selectively recognize proteins on the surface of malignant cells. An approach to enhance antitumor activity is to act on effector cells so they are increased in their numbers or enhanced in their individual (on a cell per cell basis) ADCC performance. This enhancement can be therapeutically attained by cytokines (that is, interleukin (IL)-15, IL-21, IL-18, IL-2); immunostimulatory monoclonal antibodies (that is, anti-CD137, anti-CD96, anti-TIGIT, anti-KIR, anti-PD-1); TLR agonists or by adoptive infusions of ex vivo expanded NK cells which can be genetically engineered to become more efficient effectors. In conjunction with approaches optimizing IgG1 Fc affinity to CD16, acting on effector cells offers hope to achieve synergistic immunotherapy strategies.

[Clinical features and outcomes of neuroblastoma patients aged above 5 years]

OBJECTIVE

To investigate the clinical features and outcomes of neuroblastoma (NB) children aged above 5 years, and to provide a theoretical basis for improving prognosis.

METHODS

A retrospective analysis was performed for the clinical data of 54 previously untreated NB children, and their clinical features and outcome were analyzed. The Kaplan-Meier method was used for survival analysis.

RESULTS

Among the 54 children, there were 36 boys and 18 girls, and all of them had stage 3 or 4 NB. Of all the children, 41 (41/54, 76%) had retroperitoneal space-occupying lesions, 10 (10/54, 18%) had mediastinal space-occupying lesions, 2 (2/54, 4%) had intraspinal space-occupying lesions, and 1 (1/54, 2%) had pelvic space-occupying lesions. At the end of the follow-up, 30 children (30/54, 56%) survived, among whom 23 (77%) achieved disease-free survival (9 achieved complete remission after chemotherapy for recurrence), 6 (20%) achieved partial remission of tumor (all of them received chemotherapy again due to recurrence), and 1 (3%) experienced progression (with progression after chemotherapy again due to recurrence); 24 children (44%) died, among whom 22 died after chemotherapy again due to recurrence and 2 died of multiple organ failure during the first treatment. According to the Kaplan-Meier survival analysis, the mean survival time was 53.8 months, and the children with stage 3 NB had a significantly higher overall survival rate than those with stage 4 NB (80% vs 53%; p<0.01). The children with recurrence had a significantly lower mean survival time than those without recurrence (51.68 months vs 62.57 months; p<0.01).

CONCLUSIONS

Older children often have late-stage NB, but standard treatment can improve their outcomes.

Glypican-3 Targeting Immunotoxins for the Treatment of Liver Cancer

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, yet no effective therapeutics exist. This review provides an overview of the recent development of recombinant immunotoxins for the treatment of glypican-3 (GPC3) expressing HCC. GPC3 is a cell surface heparan sulfate proteoglycan that is overexpressed in HCC, but is absent from normal adult human tissues. Treatment of HCC with anti-GPC3 immunotoxins represents a new therapeutic option. Using phage display and hybridoma technologies, three high affinity antibodies (HN3, HS20 and YP7) have been generated against GPC3. Two of these antibodies (HN3 and HS20) have demonstrated the ability to inhibit Wnt/Yap signaling, leading to a reduction in liver cancer cell proliferation. By combining the HN3 antibody capable of inhibiting Wnt/Yap signaling with the protein synthesis inhibitory domain of the Pseudomonas exotoxin, a recombinant immunotoxin that exhibits a dual inhibitory mechanism was generated. This immunotoxin was found to be highly effective in the treatment of human HCCs in mouse xenograft models. Engineering of the toxin fragment to reduce the level of immunogenicity is currently being explored. The development of immunotoxins provides opportunities for novel liver cancer therapies.