Novel Therapies for Relapsed and Refractory Neuroblastoma

Mutually exclusive teams-like patterns of gene regulation characterize phenotypic heterogeneity along the noradrenergic-mesenchymal axis in neuroblastoma

Neuroblastoma is the most frequent extracranial pediatric tumor and leads to 15% of all cancer-related deaths in children. Tumor relapse and therapy resistance in neuroblastoma are driven by phenotypic plasticity and heterogeneity between noradrenergic (NOR) and mesenchymal (MES) cell states. Despite the importance of this phenotypic plasticity, the dynamics and molecular patterns associated with these bidirectional cell-state transitions remain relatively poorly understood. Here, we analyze multiple RNA-seq datasets at both bulk and single-cell resolution, to understand the association between NOR- and MES-specific factors. We observed that NOR-specific and MES-specific expression patterns are largely mutually exclusive, exhibiting a "teams-like" behavior among the genes involved, reminiscent of our earlier observations in lung cancer and melanoma. This antagonism between NOR and MES phenotypes was also associated with metabolic reprogramming and with immunotherapy targets PD-L1 and GD2 as well as with experimental perturbations driving the NOR-MES and/or MES-NOR transition. Further, these "teams-like" patterns were seen only among the NOR- and MES-specific genes, but not in housekeeping genes, possibly highlighting a hallmark of network topology enabling cancer cell plasticity.

Evolution and contemporary role of metronomic chemotherapy in the treatment of neuroblastoma

Metronomic chemotherapy refers to the consistent and regular administration of low-dose chemotherapeutic agents over an extended period, with minimal or no extended drug-free intervals. The effectiveness of metronomic chemotherapy is derived from its capacity to impede tumor angiogenesis and foster antitumor immune responses, rather than merely interrupting tumor cell mitosis. Metronomic chemotherapy has been applied in the treatment of neuroblastoma for decades, including patients with newly diagnosed high-risk neuroblastoma and relapsed or refractory neuroblastoma. In the modern era of neuroblastoma treatment, metronomic chemotherapy remains a viable option for maintenance therapy in newly diagnosed neuroblastoma patients without access to autologous stem cell transplantation or immunotherapy, especially in resource-limited regions. For relapsed or refractory patients, metronomic chemotherapy is a suitable alternative for individuals intolerant to intensified treatments or receiving palliative care. Cyclophosphamide, etoposide, vinca alkaloids, and celecoxib constitute the primary components of current metronomic chemotherapy. Given the need for additional research to determine the optimal regimen, comprehensive studies must be conducted to explore and establish standardized metronomic chemotherapy protocols. Additionally, investigating potential biomarkers and clinical prognostic factors is imperative for future advancements in this field.

Yoga as a non-pharmacologic therapy to reduce dinutuximab-induced pain in patients with neuroblastoma

BACKGROUND

Anti-GD2 antibodies are key components of treatment for high-risk neuroblastoma; however, they cause neuropathic pain. Yoga therapy may help reduce pain and distress associated with anti-GD2 therapy.

PROCEDURE

Children 3 years of age or older with neuroblastoma participated in individualized yoga therapy while receiving the anti-GD2 antibody dinutuximab (DIN). Yoga therapy was deemed feasible if patients participated during 60% or more of DIN admissions. Patients and caregivers assessed pain/distress before and after yoga therapy with a distress thermometer (DT) and Wong-Baker FACES pain rating scale and completed questionnaires regarding satisfaction with yoga therapy. Therapy was deemed efficacious if there was a ≥1 point pain score change and reduction in distress after yoga.

RESULTS

Eighteen patients were enrolled; 52 encounters (admissions for DIN) were evaluable. Ten of 18 were female, three of 18 were Hispanic, and 10/18 were White. Median age at enrollment was 5.5 years (range: 3-11). Yoga therapy was feasible in 39/52 (75%) encounters. Significant reductions in caregiver-reported pain and distress and reductions in patient-reported pain and distress after yoga therapy were reported. Twelve of 18 caregivers completed questionnaires: seven agreed/strongly agreed that yoga was valuable, and nine agreed/strongly agreed to continued participation in yoga. Thirty-four of 36 clinicians reported that they would recommend yoga therapy for other patients receiving DIN.

CONCLUSIONS

Yoga therapy was feasible during DIN therapy and may be effective in reducing DIN-associated pain and distress. Future studies are needed to evaluate changes in opioid usage with the addition of yoga therapy during anti-GD2 antibody therapy.

Advancements in the Application of the Fenton Reaction in the Cancer Microenvironment

Cancer is a complex and multifaceted disease that continues to be a global health challenge. It exerts a tremendous burden on individuals, families, healthcare systems, and society as a whole. To mitigate the impact of cancer, concerted efforts and collaboration on a global scale are essential. This includes strengthening preventive measures, promoting early detection, and advancing effective treatment strategies. In the field of cancer treatment, researchers and clinicians are constantly seeking new approaches and technologies to improve therapeutic outcomes and minimize adverse effects. One promising avenue of investigation is the utilization of the Fenton reaction, a chemical process that involves the generation of highly reactive hydroxyl radicals (·OH) through the interaction of hydrogen peroxide (H2O2) with ferrous ions (Fe2+). The generated ·OH radicals possess strong oxidative properties, which can lead to the selective destruction of cancer cells. In recent years, researchers have successfully introduced the Fenton reaction into the cancer microenvironment through the application of nanotechnology, such as polymer nanoparticles and light-responsive nanoparticles. This article reviews the progress of the application of the Fenton reaction, catalyzed by polymer nanoparticles and light-responsive nanoparticles, in the cancer microenvironment, as well as the potential applications and future development directions of the Fenton reaction in the field of tumor treatment.

Target therapy for high-risk neuroblastoma treatment: integration of regulatory and scientific tools is needed

Introduction

Several new active substances (ASs) targeting neuroblastoma (NBL) are under study. We aim to describe the developmental and regulatory status of a sample of ASs targeting NBL to underline the existing regulatory gaps in product development and to discuss possible improvements.

Methods

The developmental and regulatory statuses of the identified ASs targeting NBL were investigated by searching for preclinical studies, clinical trials (CTs), marketing authorizations, pediatric investigation plans (PIPs), waivers, orphan designations, and other regulatory procedures.

Results

A total of 188 ASs were identified. Of these, 55 were considered 'not under development' without preclinical or clinical studies. Preclinical studies were found for 115 ASs, of which 54 were associated with a medicinal product. A total of 283 CTs (as monotherapy or in combination) were identified for 70 ASs. Of these, 52% were at phases 1, 1/2, and 2 aimed at PK/PD/dosing activity. The remaining ones also included efficacy. Phase 3 studies were limited. Studies were completed for 14 ASs and suspended for 11. The highest rate of ASs involved in CTs was observed in the RAS-MAPK-MEK and VEGF groups. A total of 37 ASs were granted with a PIP, of which 14 involved NBL, 41 ASs with a waiver, and 18 ASs with both PIPs and waivers, with the PIP covering pediatric indications different from the adult ones. In almost all the PIPs, preclinical studies were required, together with early-phase CTs often including efficacy evaluation. Two PIPs were terminated because of negative study results, and eight PIPs are in progress. Variations in the SmPC were made for larotrectinib sulfate/Vitrakvi® and entrectinib/Rozlytrek® with the inclusion of a new indication. For both, the related PIPs are still ongoing. The orphan designation has been largely adopted, while PRIME designation has been less implemented.

Discussion

Several ASs entered early phase CTs but less than one out of four were included in a regulatory process, and only two were granted a pediatric indication extension. Our results confirm that it is necessary to identify a more efficient, less costly, and time-consuming "pediatric developmental model" integrating predictive preclinical study and innovative clinical study designs. Furthermore, stricter integration between scientific and regulatory efforts should be promoted.

Evaluating the RIST Molecular-Targeted Regimen in a Three-Dimensional Neuroblastoma Spheroid Cell Culture Model

Background: The outcome for patients with high-risk neuroblastoma remains poor and novel treatment strategies are urgently needed. The RIST protocol represents a novel metronomic and multimodal treatment strategy for high-risk neuroblastoma combining molecular-targeted drugs as ‘pre-treatment’ with a conventional chemotherapy backbone, currently evaluated in a phase II clinical trial. For preclinical drug testing, cancer cell growth as spheroid compared to mo-nolayer cultures is of advantage since it reproduces a wide range of tumor characteristics, including the three-dimensional architecture and cancer stem cell (CSC) properties. The objective of this study was to establish a neuroblastoma spheroid model for the rigorous assessment of the RIST treatment protocol. Methods: Evaluation of CSC marker expression was performed by mRNA and protein analysis and spheroid viability by luminescence-based assays. Aberrant expression of RNA-binding protein La in neuroblastoma was assessed by tissue microarray analysis and patients’ data mining. Results: Spheroid cultures showed increased expression of a subgroup of CSC-like markers (CXCR4, NANOG and BMI) and higher Thr389 phosphorylation of the neuroblastoma-associated RNA-binding protein La when compared to monolayer cultures. Molecular-targeted ‘pre-treatment’ of spheroids decreased neoplastic signaling and CSC marker expression. Conclusions: The RIST treatment protocol efficiently reduced the viability of neuroblastoma spheroids characterized by advanced CSC properties.

Identification of ALK Mutation in Neuroblastoma on the Point of Molecular Heterogeneity

BACKGROUND AND AIM

In neuroblastoma, anaplastic lymphoma kinase mutations have recently received attention as molecular targets for the treatment of neuroblastoma, as 6% to 10% of patients with neuroblastoma have anaplastic lymphoma kinase mutations. There are little data from the cases in Turkey. We aimed to detect anaplastic lymphoma kinase mutations and molecular heterogeneity in neuroblastoma using next-generation sequencing. This study is the first one with this many cases in Turkey.

METHODS

Next-generation sequencing analysis was performed using an Illumina MiniSeq custom gene panel. Clinically important mutations were selected for the analysis. We also gathered clinical data of the patients from Turkish Pediatric Oncology Group cohorts to associate them with anaplastic lymphoma kinase mutations. This study is a retrospective cross-sectional study. We followed STROBE guideline (https://www.equator-network.org/reporting-guidelines/strobe/) on this study.

RESULTS

We analyzed anaplastic lymphoma kinase in 108 patients with neuroblastoma, with a mean age of 43.76 months. Pathogenic anaplastic lymphoma kinase mutations were detected in 13 patients (12.04%). We noted that anaplastic lymphoma kinase mutations were primarily observed in intermediate- and high-risk patients (P  =  .028). R1275Q and F1174-related mutations were predominant; I1171T, L1226F, S1189F, V1135A, and G1125S mutations were rare. Duplicate samples did not exhibit any heterogeneity.

CONCLUSIONS

We found that F1174 and R1275Q-related anaplastic lymphoma kinase mutations are the most common pathogenic mutations in neuroblastoma. Anaplastic lymphoma kinase mutation status did not show any heterogeneity, and the mutations were correlated with intermediate- or high-risk groups.

Strategies for Potentiating NK-Mediated Neuroblastoma Surveillance in Autologous or HLA-Haploidentical Hematopoietic Stem Cell Transplants

Simple Summary

High-risk neuroblastomas (HR-NB) are malignant tumors of childhood that are treated with a very aggressive and life-threatening approach; this includes autologous hemopoietic stem cell transplantation (HSCT) and the infusion of a mAb targeting the GD2 tumor-associated antigen. Although the current treatment provided benefits, the 5-year overall survival remains below 50% due to relapses and refractoriness to therapy. Thus, there is an urgent need to ameliorate the standard therapeutic protocol, particularly improving the immune-mediated anti-tumor responses. Our review aims at summarizing and critically discussing novel immunotherapeutic strategies in HR-NB, including NK cell-based therapies and HLA-haploidentical HSCT from patients’ family.

Abstract

High-risk neuroblastomas (HR-NB) still have an unacceptable 5-year overall survival despite the aggressive therapy. This includes standardized immunotherapy combining autologous hemopoietic stem cell transplantation (HSCT) and the anti-GD2 mAb. The treatment did not significantly change for more than one decade, apart from the abandonment of IL-2, which demonstrated unacceptable toxicity. Of note, immunotherapy is a promising therapeutic option in cancer and could be optimized by several strategies. These include the HLA-haploidentical αβT/B-depleted HSCT, and the antibody targeting of novel NB-associated antigens such as B7-H3, and PD1. Other approaches could limit the immunoregulatory role of tumor-derived exosomes and potentiate the low antibody-dependent cell cytotoxicity of CD16 dim/neg NK cells, abundant in the early phase post-transplant. The latter effect could be obtained using multi-specific tools engaging activating NK receptors and tumor antigens, and possibly holding immunostimulatory cytokines in their construct. Finally, treatments also consider the infusion of novel engineered cytokines with scarce side effects, and cell effectors engineered with chimeric antigen receptors (CARs). Our review aims to discuss several promising strategies that could be successfully exploited to potentiate the NK-mediated surveillance of neuroblastoma, particularly in the HSCT setting. Many of these approaches are safe, feasible, and effective at pre-clinical and clinical levels.

Personalized dosimetry for a deeper understanding of metastatic response to high activity 131I-mIBG therapy in high risk relapsed refractory neuroblastoma

Background

Dosimetry in molecular radiotherapy for personalized treatment is assuming a central role in clinical management of aggressive/relapsed tumors. Relapsed/refractory metastatic high-risk neuroblastoma (rrmHR-NBL) has a poor prognosis and high-activity ¹³¹I-mIBG therapy could represent a promising strategy. The primary aim of this case series study was to report the absorbed doses to whole-body (D_WB ), red marrow (D_RM ) and lesions (D_Lesion ). A secondary aim was to correlate D_Lesion values to clinical outcome.

Methods

Fourteen patients affected by rrmHR-NBL were treated with high-activity ¹³¹I-mIBG therapy (two administrations separated by 15 days). The first administration was weight-based whereas the second one was dosimetry-based (achieving D_WB equals to 4 Gy). In all patients D_WB and D_RM was assessed; 9/14 patients were selected for D_Lesion evaluation using planar dosimetric approach (13 lesions evaluated). Treatment response was classified as progressive and stable disease (PD and SD), partial and complete response (PR and CR) according to the International Neuroblastoma Response Criteria. Patients were divided into two groups: Responder (CR, PR, SD) and Non-Responder (PD), correlating treatment response to D_Lesion value.

Results

The cumulative D_WB , D_RM and D_Lesion ranged from (1.5; 4.5), (1.0; 2.6) and (44.2; 585.8) Gy. A linear correlation between D_WB and D_RM and a power law correlation between the absorbed dose to WB normalized for administered activity and the mass of the patient were observed. After treatment 3, 2, 4 and 5 patients showed CR, PR, SD and PD respectively, showing a correlation between D_Lesion and the two response group.

Conclusions

Our experience demonstrated feasibility of high activity therapy of ¹³¹I-mIBG in rrmHR-NBL children as two administration intensive strategy. Dosimetric approach allowed a tailored high dose treatment maximizing the benefits of radionuclide therapy for pediatric patients while maintaining a safety profile. The assesment of D_Lesion contributed to have a deeper understaning of metabolic treatment effects.

Nanocarrier-Based Delivery of SN22 as a Tocopheryl Oxamate Prodrug Achieves Rapid Tumor Regression and Extends Survival in High-Risk Neuroblastoma Models

Despite the use of intensive multimodality therapy, the majority of high-risk neuroblastoma (NB) patients do not survive. Without significant improvements in delivery strategies, anticancer agents used as a first-line treatment for high-risk tumors often fail to provide clinically meaningful results in the settings of disseminated, recurrent, or refractory disease. By enhancing pharmacological selectivity, favorably shifting biodistribution, strengthening tumor cell killing potency, and overcoming drug resistance, nanocarrier-mediated delivery of topoisomerase I inhibitors of the camptothecin family has the potential to dramatically improve treatment efficacy and minimize side effects. In this study, a structurally enhanced camptothecin analog, SN22, reversibly coupled with a redox-silent tocol derivative (tocopheryl oxamate) to allow its optimally stable encapsulation and controlled release from PEGylated sub-100 nm nanoparticles (NP), exhibited strong NB cell growth inhibitory activity, translating into rapid regression and durably suppressed regrowth of orthotopic, MYCN-amplified NB tumors. The robust antitumor effects and markedly extended survival achieved in preclinical models recapitulating different phases of high-risk disease (at diagnosis vs. at relapse with an acquired loss of p53 function after intensive multiagent chemotherapy) demonstrate remarkable potential of SN22 delivered in the form of a hydrolytically cleavable superhydrophobic prodrug encapsulated in biodegradable nanocarriers as an experimental strategy for treating refractory solid tumors in high-risk cancer patients.

Relapsed Medulloblastoma in Pre-Irradiated Patients: Current Practice for Diagnostics and Treatment

Relapsed medulloblastoma (rMB) accounts for a considerable, and disproportionate amount of childhood cancer deaths. Recent advances have gone someway to characterising disease biology at relapse including second malignancies that often cannot be distinguished from relapse on imaging alone. Furthermore, there are now multiple international early-phase trials exploring drug-target matches across a range of high-risk/relapsed paediatric tumours. Despite these advances, treatment at relapse in pre-irradiated patients is typically non-curative and focuses on providing life-prolonging and symptom-modifying care that is tailored to the needs and wishes of the individual and their family. Here, we describe the current understanding of prognostic factors at disease relapse such as principal molecular group, adverse molecular biology, and timing of relapse. We provide an overview of the clinical diagnostic process including signs and symptoms, staging investigations, and molecular pathology, followed by a summary of treatment modalities and considerations. Finally, we summarise future directions to progress understanding of treatment resistance and the biological mechanisms underpinning early therapy-refractory and relapsed disease. These initiatives include development of comprehensive and collaborative molecular profiling approaches at relapse, liquid biopsies such as cerebrospinal fluid (CSF) as a biomarker of minimal residual disease (MRD), modelling strategies, and the use of primary tumour material for real-time drug screening approaches.

In Vitro Assessment of the Role of p53 on Chemotherapy Treatments in Neuroblastoma Cell Lines

Neuroblastoma is the most frequent malignant extracranial solid tumor of infancy. The overall objective of this work consists of determining the presence of alterations in the p53/MDM2/p14ARF signaling pathway in neuroblastoma cell lines and deciphering their possible relationship with resistance to known antineoplastic drugs and to differentiation agents. Firstly, we characterized 10 neuroblastoma cell lines for alterations at the p53/MDM2/p14ARF signaling pathway by analysis of TP53 point mutations, MYCN and MDM2 amplification, and p14ARF methylation, homozygous deletions, and expression. Secondly, we chose SK-N-FI (mutated at TP53) and SK-N-Be(2) (wild-type TP53) cell lines, treated them with chemotherapeutic agents (doxorubicin, etoposide, cisplatin, and melphalan) and with two isomers of retinoic acid (RA): (9-cis and all-trans). Finally, we analyzed the distribution of the cell cycle, the induction of apoptosis, and the expression levels of p53, p21, and Bcl-2 in those two cell lines. P14ARF did not present promoter methylation, homozygous deletions, and protein expression in any of the 10 neuroblastoma cell lines. One TP53 point mutation was detected in the SK-N-FI cell line. MYCN amplification was frequent, while most cell lines did not present MDM2 amplification. Treatment of SK-N-FI and SK-N-Be(2) cells with doxorubicin, etoposide, cisplatin, and melphalan increased apoptosis and blocked the cycle in G2/M, while retinoic acid isomers induced apoptosis and decreased the percentage of cells in S phase in TP53 mutated SK-N-FI cells, but not in TP53 wild-type SK-N-Be(2) cells. Treatment with cisplatin, melphalan, or 9-cis RA decreased p53 expression levels in SK-N-FI cells but not in SK-N-Be (2). The expression of p21 was not modified in either of the two cell lines. Bcl-2 levels were reduced only in SK-N-FI cells after treatment with cisplatin. However, treatments with doxorubicin, etoposide, or 9-cis-RA did not modify the levels of this protein in either of the two cell lines. In conclusion, TP53 mutated SK-N-FI cells respond better to the retinoic isomers than TP53 wild-type SK-N-Be(2) cells. Although these are in vitro results, it seems that deciphering the molecular alterations of the p53/MDM2/p14ARF signaling pathway prior to treating patients of neuroblastoma might be useful for standardizing therapies with the aim of improving survival.

Phenotypic changes on central nervous system (CNS) tumor cell lines cultured in vitro 2D and 3D models and treated with cisplatin

Despite aggressive therapy, most patients with brain tumors present disease relapse due to the cellular and molecular nature of these tumors. One of the models that best explains the heterogeneity observed in CNS tumors is the presence of cancer stem cells (CSCs). In this paper, we evaluated platinum-based response in brain tumor U-87 MG, LN-18, and KELLY cell lines cultured in monolayer (2D) and neurosphere (CSC enrichment- 3D) models. We evaluated mRNA expression of heat shock proteins (HSPA1A, HSPB1, HSPA1AL, TRAP1, and HSPD1), and DNA repair gene ERCC1. Changes in cell cycle and glycosylation profile were assessed by flow cytometry. After treatment with cisplatin, we found that the mRNA expression of HSPs markedly increased in the U-87 MG and LN-18 neurosphere cells. In KELLY monolayer cells, cisplatin induced upregulation of all genes. In KELLY neurosphere cells, only the HSPA1A, HSPB1, TRAP1, and HSPD1 genes were upregulated. The proportion of cells in the G₀/G₁ phase was significantly higher in U-87 MG neurosphere cisplatin-treated cells. A trend towards a greater proportion of cells in the S phase of U-87 MG monolayer cisplatin-treated cells was also observed. On the other hand, a significant decrease in the number of cells in the S phase and an increase in G₂/M was observed in LN-18 monolayer cisplatin-treated cells. Glycosylation analysis using lectins showed a higher surface binding for PNA in the U-87 MG treated monolayer and a lower binding for Concanavalin A in the treated neurospheres. The binding of Isolectin GS-IB4, GSII, and SBA in KELLY monolayer cisplatin-treated cells was lower whereas the proportion of cells labeled with Concanavalin A was higher. In the KELLY neurosphere cisplatin-treated cells, the binding of Concanavalin A was lower than nontreated cells. Thus, our findings strongly supported the idea that definitions of phenotypic characteristics may help to establish better therapeutic strategies for brain tumors.

A model of modified meta-iodobenzylguanidine conjugated gold nanoparticles for neuroblastoma treatment

Iodine-131 meta-iodobenzylguanidine (131I-mIBG) has been utilized as a standard treatment to minimize adverse side effects by targeting therapies to bind to the norepinephrine transporter (NET) expressed on 90% of neuroblastoma cells. However, only a minority of patients who receive 131I-mIBG radiotherapy have clinical responses, and these are usually not curative. In this study, novel ligand-conjugated gold nanoparticles (GNPs) based on mIBG were synthesized and evaluated biologically with neuroblastoma cells in vitro. To induce specific internalization to the tumor cells and utilize it as a model for radioenhancement, 127I-modified mIBG was successfully synthesized and grafted covalently to the surface of carboxylated PEG-GNPs. 49.28% of the novel mIBG derivative was grafted on carboxylated PEG-GNPs. The particles were stable and not toxic to the normal fibroblast cell line, L929, even at the highest concentration tested (1013 NPs per mL) at 24, 48, and 72 h. Moreover, the cellular uptake of the model was decreased significantly in the presence of a NET inhibitor, suggesting that there was specific internalization into neuroblastoma cells line (SH-SY5Y) via the NET. Therefore, this model provides useful guidance toward the design of gold nanomaterials to enhance the efficiency of 131I-mIBG treatment in neuroblastoma patients. However, the investigation of radio-therapeutic efficiency after radioisotope 131I substitution will be further conducted in a radiation safety laboratory using an animal model.

Connectivity Map Analysis Indicates PI3K/Akt/mTOR Inhibitors as Potential Anti-Hypoxia Drugs in Neuroblastoma

Neuroblastoma (NB) is one of the deadliest pediatric cancers, accounting for 15% of deaths in childhood. Hypoxia is a condition of low oxygen tension occurring in solid tumors and has an unfavorable prognostic factor for NB. In the present study, we aimed to identify novel promising drugs for NB treatment. Connectivity Map (CMap), an online resource for drug repurposing, was used to identify connections between hypoxia-modulated genes in NB tumors and compounds. Two sets of 34 and 21 genes up- and down-regulated between hypoxic and normoxic primary NB tumors, respectively, were analyzed with CMap. The analysis reported a significant negative connectivity score across nine cell lines for 19 compounds mainly belonging to the class of PI3K/Akt/mTOR inhibitors. The gene expression profiles of NB cells cultured under hypoxic conditions and treated with the mTORC complex inhibitor PP242, referred to as the Mohlin dataset, was used to validate the CMap findings. A heat map representation of hypoxia-modulated genes in the Mohlin dataset and the gene set enrichment analysis (GSEA) showed an opposite regulation of these genes in the set of NB cells treated with the mTORC inhibitor PP242. In conclusion, our analysis identified inhibitors of the PI3K/Akt/mTOR signaling pathway as novel candidate compounds to treat NB patients with hypoxic tumors and a poor prognosis.

Personalized Medicine for Neuroblastoma: Moving from Static Genotypes to Dynamic Simulations of Drug Response

High-risk neuroblastoma is an aggressive childhood cancer that is characterized by high rates of chemoresistance and frequent metastatic relapse. A number of studies have characterized the genetic and epigenetic landscape of neuroblastoma, but due to a generally low mutational burden and paucity of actionable mutations, there are few options for applying a comprehensive personalized medicine approach through the use of targeted therapies. Therefore, the use of multi-agent chemotherapy remains the current standard of care for neuroblastoma, which also conceptually limits the opportunities for developing an effective and widely applicable personalized medicine approach for this disease. However, in this review we outline potential approaches for tailoring the use of chemotherapy agents to the specific molecular characteristics of individual tumours by performing patient-specific simulations of drug-induced apoptotic signalling. By incorporating multiple layers of information about tumour-specific aberrations, including expression as well as mutation data, these models have the potential to rationalize the selection of chemotherapeutics contained within multi-agent treatment regimens and ensure the optimum response is achieved for each individual patient.

Comparing mTOR inhibitor Rapamycin with Torin-2 within the RIST molecular-targeted regimen in neuroblastoma cells

The prognosis for patients with relapsed or refractory high-risk neuroblastoma remains dismal and novel therapeutic options are urgently needed. The RIST treatment protocol has a multimodal metronomic therapy design combining molecular-targeted drugs (Rapamycin and Dasatinib) with chemotherapy backbone (Irinotecan and Temozolomide), which is currently verified in a phase II clinical trial (NCT01467986). With the availability of novel and more potent ATP competitive mTOR inhibitors, we expect to improve the RIST combination therapy. By comparing the IC50 values of Torin-1, Torin-2, AZD3147 and PP242 we established that only Torin-2 inhibited cell viability of all three MycN-amplified neuroblastoma cell lines tested at nanomolar concentration. Single treatment of both mTOR inhibitors induced a significant G1 cell cycle arrest and combination treatment with Dasatinib reduced the expression of cell cycle regulator cyclin D1 or increased the expression of cell cycle inhibitor p21. The combinatorial index depicted for both mTOR inhibitors a synergistic effect with Dasatinib. Interestingly, compared to Rapamycin, the combination treatment with Torin-2 resulted in a broader mTOR pathway inhibition as indicated by reduced phosphorylation of AKT (Thr308, Ser473), 4E-BP (Ser65), and S6K (Thr389). Furthermore, substituting Rapamycin in the modified multimodal RIST protocol with Torin-2 reduced cell viability and induced apoptosis despite a significant lower Torin-2 drug concentration applied. The efficacy of nanomolar concentrations may significantly reduce unwanted immunosuppression associated with Rapamycin. However, at this point we cannot rule out that Torin-2 has increased toxicity due to its potency in more complex systems. Nonetheless, our results suggest that including Torin-2 as a substitute for Rapamycin in the RIST protocol may represent a valid option to be evaluated in prospective clinical trials for relapsed or treatment-refractory high-risk neuroblastoma.

Targeting MDM2 for Neuroblastoma Therapy: In Vitro and In Vivo Anticancer Activity and Mechanism of Action

Simple Summary

Neuroblastoma is a malignant tumor of the sympathetic nervous system that causes aggressive disease in children. The overall survival rate of high-risk patients is very low, therefore developing effective and safe therapies for neuroblastoma is an urgent unmet medical need. The mouse double minute 2 (MDM2) homolog gene is amplified and overexpressed in neuroblastoma and contributes to the poor response to treatment and poor prognosis in patients with high-risk neuroblastoma. Therefore, targeting MDM2 provides a promising approach to neuroblastoma therapy, especially for advanced disease. In the present study, we tested a unique MDM2 inhibitor, SP141, for its therapeutic efficacy and safety in neuroblastoma tumor models. We found that SP141 has significant anti- neuroblastoma activity in cell culture and inhibits tumor growth in animal models of human neuroblastoma, without any noticeable host toxicity. These results provide the basis for targeting MDM2 to treat high-risk neuroblastoma.

Abstract

Background: Neuroblastoma is an aggressive pediatric solid tumor with an overall survival rate of <50% for patients with high-risk disease. The majority (>98%) of pathologically-diagnosed neuroblastomas have wild-type p53 with intact functional activity. However, the mouse double minute 2 (MDM2) homolog, an E3 ubiquitin ligase, is overexpressed in neuroblastoma and leads to inhibition of p53. MDM2 also exerts p53-independent oncogenic functions. Thus, MDM2 seems to be an attractive target for the reactivation of p53 and attenuation of oncogenic activity in neuroblastoma. Methods: In this study, we evaluated the anticancer activities and underlying mechanisms of action of SP141, a first-in-class MDM2 inhibitor, in neuroblastoma cell lines with different p53 backgrounds. The findings were confirmed in mouse xenograft models of neuroblastoma. Results: We demonstrate that SP141 reduces neuroblastoma cell viability, induces apoptosis, arrests cells at the G2/M phase, and prevents cell migration, independent of p53. In addition, in neuroblastoma xenograft models, SP141 inhibited MDM2 expression and suppressed tumor growth without any host toxicity at the effective dose. Conclusions: MDM2 inhibition by SP141 results in the inhibition of neuroblastoma growth and metastasis, regardless of the p53 status of the cells and tumors. These findings provide proof-of-concept that SP141 represents a novel treatment option for both p53 wild-type and p53 null neuroblastoma.

Thymoquinone-Loaded Soluplus®-Solutol® HS15 Mixed Micelles: Preparation, In Vitro Characterization, and Effect on the SH-SY5Y Cell Migration

Thymoquinone (TQ) is the main active ingredient of Nigella sativa essential oil, with remarkable anti-neoplastic activities with anti-invasive and anti-migratory abilities on a variety of cancer cell lines. However, its poor water solubility, high instability in aqueous solution and pharmacokinetic drawbacks limits its use in therapy. Soluplus^® and Solutol^® HS15 were employed as amphiphilic polymers for developing polymeric micelles (SSM). Chemical and physical characterization studies of micelles are reported, in terms of size, homogeneity, zeta potential, critical micelle concentration (CMC), cloud point, encapsulation efficiency (EE%), load capacity (DL), in vitro release, and stability. This study reports for the first time the anti-migratory activity of TQ and TQ loaded in SSM (TQ-SSM) in the SH-SY5Y human neuroblastoma cell line. The inhibitory effect was assessed by the wound-healing assay and compared with that of the unformulated TQ. The optimal TQ-SSM were provided with small size (56.71 ± 1.41 nm) and spherical shape at ratio of 1:4 (Soluplus:Solutol HS15), thus increasing the solubility of about 10-fold in water. The entrapment efficiency and drug loading were 92.4 ± 1.6% and 4.68 ± 0.12, respectively, and the colloidal dispersion are stable during storage for a period of 40 days. The TQ-SSM were also lyophilized to obtain a more workable product and with increased stability. In vitro release study indicated a prolonged release of TQ. In conclusion, the formulation of TQ into SSM allows a bio-enhancement of TQ anti-migration activity, suggesting that TQ-SSM is a better candidate than unformulated TQ to inhibit human SH-SY5Y neuroblastoma cell migration.

Amino Acids Regulate Cisplatin Insensitivity in Neuroblastoma

Simple Summary

Neuroblastomas mostly show poor response to the Cisplatin therapy. Amino acids serve as building blocks for proteins, which are acquired either through diet or protein breakdown. Our study reveals high amino acid pools and dependence of Cisplatin-tolerant neuroblastomas cells on amino acids for their survival, especially, in drug treated conditions. Our study also demonstrates that response of neuroblastomas to Cisplatin can be improved by decreasing cellular amino acid levels either by reducing amino acid supplements or by applying autophagy inhibitor, Hydroxychloroquine. Thus, our findings establish that neuroblastomas can be sensitized to Cisplatin by targeting amino acid metabolism.

Abstract

Neuroblastoma are pediatric, extracranial malignancies showing alarming survival prognosis outcomes due to their resilience to current aggressive treatment regimens, including chemotherapies with cisplatin (CDDP) provided in the first line of therapy regimens. Metabolic deregulation supports tumor cell survival in drug-treated conditions. However, metabolic pathways underlying cisplatin-resistance are least studied in neuroblastoma. Our metabolomics analysis revealed that cisplatin-insensitive cells alter their metabolism; especially, the metabolism of amino acids was upregulated in cisplatin-insensitive cells compared to the cisplatin-sensitive neuroblastoma cell line. A significant increase in amino acid levels in cisplatin-insensitive cells led us to hypothesize that the mechanisms upregulating intracellular amino acid pools facilitate insensitivity in neuroblastoma. We hereby report that amino acid depletion reduces cell survival and cisplatin-insensitivity in neuroblastoma cells. Since cells regulate their amino acids levels through processes, such as autophagy, we evaluated the effects of hydroxychloroquine (HCQ), a terminal autophagy inhibitor, on the survival and amino acid metabolism of cisplatin-insensitive neuroblastoma cells. Our results demonstrate that combining HCQ with CDDP abrogated the amino acid metabolism in cisplatin-insensitive cells and sensitized neuroblastoma cells to sub-lethal doses of cisplatin. Our results suggest that targeting of amino acid replenishing mechanisms could be considered as a potential approach in developing combination therapies for treating neuroblastomas.

Hypoxia Predicts Poor Prognosis in Neuroblastoma Patients and Associates with Biological Mechanisms Involved in Telomerase Activation and Tumor Microenvironment Reprogramming

The biological and clinical heterogeneity of neuroblastoma (NB) demands novel biomarkers and therapeutic targets in order to drive the most appropriate treatment for each patient. Hypoxia is a condition of low-oxygen tension occurring in poorly vascularized tumor tissues. In this study, we aimed to assess the role of hypoxia in the pathogenesis of NB and at developing a new clinically relevant hypoxia-based predictor of outcome. We analyzed the gene expression profiles of 1882 untreated NB primary tumors collected at diagnosis and belonging to four existing data sets. Analyses took advantage of machine learning methods. We identified NB-hop, a seven-gene hypoxia biomarker, as a predictor of NB patient prognosis, which is able to discriminate between two populations of patients with unfavorable or favorable outcome on a molecular basis. NB-hop retained its prognostic value in a multivariate model adjusted for established risk factors and was able to additionally stratify clinically relevant groups of patients. Tumors with an unfavorable NB-hop expression showed a significant association with telomerase activation and a hypoxic, immunosuppressive, poorly differentiated, and apoptosis-resistant tumor microenvironment. NB-hop defines a new population of NB patients with hypoxic tumors and unfavorable prognosis and it represents a critical factor for the stratification and treatment of NB patients.

Nanoformulation of CCL21 greatly increases its effectiveness as an immunotherapy for neuroblastoma

Neuroblastoma is the most commonly diagnosed extracranial solid tumor in children. The patients with aggressive metastatic disease or refractory/relapsed neuroblastoma currently face a dismally low chance of survival. Thus, there is a great need for more effective therapies for this illness. In previous studies, we, as well as others, showed that the immune cell chemoattractant C-C motif chemokine ligand 21 (CCL21) is effective as an intratumoral therapy able to slow the growth of cancers. In this current study, we developed and tested an injectable, slow-release, uniform, and optimally loaded alginate nanoformulation of CCL21 as a means to provide prolonged intratumoral treatment. The alginate-nanoformulated CCL21, when injected intratumorally into mice bearing neuroblastoma lesions, significantly prolonged survival and decreased the tumor growth rate compared to CCL21 alone, empty nanoparticles, or buffer. Notably, we also observed complete tumor clearance and subsequent full protection against tumor rechallenge in 33% of nanoformulated CCL21-treated mice. Greater intratumoral presence of nanoformulated CCL21, compared to free CCL21, at days 1 and 2 after treatment ended was confirmed through fluorescent labeling and tracking. Nanoformulated CCL21-treated tumors exhibited a general pattern of prolonged increases in anti-tumor cytokines and relatively lower levels of pro-tumor cytokines in comparison to tumors treated with CCL21 alone or buffer only. Thus, this novel nanoformulation of CCL21 is an effective treatment for neuroblastoma, and may have potential for the delivery of CCL21 to other types of solid tumors in the future and as a slow-release delivery modality for other immunotherapies.

Optimizing care for high-risk neuroblastoma patients treated with dinutuximab: Challenges for the multidisciplinary team

Current treatment protocols for high-risk neuroblastoma include high-dose chemotherapy, surgery, stem cell transplantation and radiation. Recently, dinutuximab, a chimeric monoclonal antibody, specifically targeting the disialoganglioside highly expressed on neuroblastoma cells, has been licensed. Its incorporation in maintenance therapy represents a promising treatment approach. The introduction of its use was a challenge for the entire multidisciplinary team in our pediatric hematology and oncology ward just as for the pharmacy team. An overview of the key points that were observed is presented.

Selenium enhances TRPA1 channel-mediated activity of temozolomide in SH-SY5Y neuroblastoma cells

PURPOSE

Neuroblastoma is a malignant solid tumor that originates from the sympathetic nervous system in early childhood. Temozolomide is used for treatment in high-risk groups with low treatment response of neuroblastomas. TRPA1 channels in neuroblastoma cells are calcium permeable channels that can be activated by reactive oxygen species (ROT). In this study, we aimed to evaluate the level of activity of temozolomide and selenium in neuroblastoma cells via TRPA1 channels.

METHOD

Seven main groups were formed using SH-SY5Y neuroblastoma cells. The control was divided into temozolomide (TMZ) (100 μM, 24 h), TMZ+SEL+AP18, SEL (sodium selenite, 100 μM, 24 h), and SEL+AP18 groups. Intergroup calcium signaling, intracellular reactive oxygen species, caspase-3 and caspase-9, and mitochondrial depolarization analyses were performed by channel activation with TRPA1 agonist cinnamaldehyde in all groups.

RESULTS

Cytosolic calcium concentration, apoptosis, caspase-3 and caspase-9 activation, mitochondrial membrane depolarization, and ROT levels were higher in TMZ (p < 0.001), TMZ+SEL (p < 0.001), and SEL (p < 0.05) groups than the control group. TRPA1 was lower in TTMZ+AP18, TMZ+SEL+AP18, and SEL+AP18 groups with channel blockers than respectively TMZ, TMZ+SEL, and SEL groups without channel blockers (p < 0.05).

CONCLUSION

The use of selenium with temozolomide increased the apoptotic efficacy of temozolomide via TRPA1 channels on tumor cells.

Monitoring Immune Responses in Neuroblastoma Patients during Therapy

Neuroblastoma (NBL) is the most common extracranial solid tumor in childhood. Despite intense treatment, children with this high-risk disease have a poor prognosis. Immunotherapy showed a significant improvement in event-free survival in high-risk NBL patients receiving chimeric anti-GD2 in combination with cytokines and isotretinoin after myeloablative consolidation therapy. However, response to immunotherapy varies widely, and often therapy is stopped due to severe toxicities. Objective markers that help to predict which patients will respond or develop toxicity to a certain treatment are lacking. Immunotherapy guided via immune monitoring protocols will help to identify responders as early as possible, to decipher the immune response at play, and to adjust or develop new treatment strategies. In this review, we summarize recent studies investigating frequency and phenotype of immune cells in NBL patients prior and during current treatment protocols and highlight how these findings are related to clinical outcome. In addition, we discuss potential targets to improve immunogenicity and strategies that may help to improve therapy efficacy. We conclude that immune monitoring during therapy of NBL patients is essential to identify predictive biomarkers to guide patients towards effective treatment, with limited toxicities and optimal quality of life.

Protein tyrosine phosphatase PTPN1 modulates cell growth and associates with poor outcome in human neuroblastoma

Background

Protein tyrosine phosphatases (PTPs) regulate neuronal differentiation and survival, but their expression patterns and functions in human neuroblastoma (NB) are scarcely known. Here, we have investigated the function and expression of the non-receptor PTPN1 on human NB cell lines and human NB tumor samples.

Material/methods

NB tumor samples from 44 patients were analysed by immunohistochemistry using specific antibodies against PTPN1, PTPRH, PTPRZ1, and PTEN. PTPN1 knock-down, cell proliferation and tyrosine phosphorylation analyses, and RT-qPCR mRNA expression was assessed on SH-SY5Y, SMS-KCNR, and IMR-32 human NB cell lines.

Results

Knock-down of PTPN1 in SH-SY5Y NB cells resulted in increased tyrosine phosphorylation and cell proliferation. Retinoic acid-mediated differentiation of NB cell lines did not affect PTPN1 mRNA expression, as compared with other PTPs. Importantly, PTPN1 displayed high expression on NB tumors in association with metastasis and poor prognosis.

Conclusions

Our results identify PTPN1 as a candidate regulator of NB cell growth and a potential NB prognostic biomarker.

Clinical outcomes and prognostic factors to predict treatment response in high risk neuroblastoma patients receiving topotecan and cyclophosphamide containing induction regimen: a prospective multicenter study

BACKGROUND

Neuroblastoma is the most common extra-cranial solid tumor among children. Despite intensive treatment, patients with advanced disease mostly experience dismal outcomes. Here, we proposed the use of topotecan and cyclophosphamide containing induction regimen as an upfront therapy to high risk neuroblastoma patients.

METHODS

Patients with high risk neuroblastoma undergoing ThaiPOG high risk neuroblastoma protocol from 2016 to 2017 were studied. All patients received 6 cycles of induction regimen consisting of 2 cycles topotecan (1.2 mg/m²/day) and cyclophosphamide (400 mg/m²/day) for 5 days followed by cisplatin (50 mg/m²/day) for 4 days combined with etoposide (200 mg/m²/day) for 3 days on the third and fifth cycles and cyclophosphamide (2100 mg/m²/day) for 2 days combined with doxorubicin (25 mg/m²/day) and vincristine (0.67 mg/m²/day) for 3 days on the fourth and sixth cycles. Treatment response after the 5th cycle before surgery and treatment-related toxicities after each topotecan containing induction cycle were evaluated. Relevant prognostic factors were analyzed to measure the treatment response among those patients.

RESULTS

In all, 107 high risk neuroblastoma patients were enrolled in the study. After the 5th cycle of induction regimen, the patients achieved complete response (N = 2), very good partial response (N = 40), partial response (N = 46) and mixed response (N = 19). None of the patients experienced stable disease or disease progression. The most significant prognostic factor was type of healthcare system. The most common adverse effect was febrile neutropenia followed by mucositis, diarrhea and elevated renal function.

CONCLUSION

The topotecan and cyclophosphamide containing induction regimen effectively provides favorable treatment response. The regimen is well tolerated with minimal toxicity among patients with high risk neuroblastoma in Thailand.

Modulation of all-trans retinoic acid-induced MiRNA expression in neoplastic cell lines: a systematic review

Background

Cancer is a genetic and epigenetic disease that involves inactivation of tumor suppressor genes and activation of proto-oncogenes. All-trans retinoic acid (ATRA) is an isomer of retinoic acid involved in the onset of differentiation and apoptosis of a number of normal and cancer cells, functioning as an anti-cancer agent in several neoplasms. Ectopic changes in the expression of certain microRNAs (miRNAs) occur in response to ATRA, leading to phenotypic alterations in neoplastic cell lines. Moreover, the modulation of miRNA patterns upon ATRA-treatment may represent an effective chemopreventive and anti-cancer therapy strategy. The present systematic review was performed to provide an overview of the modulation of ATRA-induced miRNA expression in different types of neoplastic cells and identify the efficacy of intervention factors (i.e., concentration and duration of treatment) and how they influence expression profiles of oncogenesis-targeting miRNAs.

Methods

A systematic search was conducted according to the PRISMA statement via the US National Library of Medicine MEDLINE/PubMed bibliographic search engine.

Results

The search identified 31 experimental studies involving human cell lines from nine different cancer types (neuroblastoma, acute myeloid leukemia, breast cancer, lung cancer, pancreatic cancer, glioma, glioblastoma, embryonal carcinoma, and colorectal cancer) treated with ATRA at concentrations ranging from 10^− 3 μmol/L to 10² μmol mol/L for 24 h to 21 days.

Conclusion

The concentrations used and the duration of treatment of cancer cells with ATRA varied widely. The presence of ATRA in the culture medium of cancer cells was able to modulate the expression of more than 300 miRNAs, and inhibit invasive behavior and deregulated growth of cancer cells, resulting in total tumor remission in some cases. ATRA may thus be broadly effective for neoplasm treatment and prevention, although these studies may not accurately represent in vivo conditions. Additional studies are required to elucidate ATRA-induced miRNA modulation during neoplasm treatment.

Targeting anaplastic lymphoma kinase in neuroblastoma

Over the last decade, anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase (RTK), has been identified as a fusion partner in a diverse variety of translocation events resulting in oncogenic signaling in many different cancer types. In tumors where the full‐length ALK RTK itself is mutated, such as neuroblastoma, the picture regarding the role of ALK as an oncogenic driver is less clear. Neuroblastoma is a complex and heterogeneous tumor that arises from the neural crest derived peripheral nervous system. Although high‐risk neuroblastoma is rare, it often relapses and becomes refractory to treatment. Thus, neuroblastoma accounts for 10–15% of all childhood cancer deaths. Since most cases are in children under the age of 2, understanding the role and regulation of ALK during neural crest development is an important goal in addressing neuroblastoma tumorigenesis. An impressive array of tyrosine kinase inhibitors (TKIs) that act to inhibit ALK have been FDA approved for use in ALK‐driven cancers. ALK TKIs bind differently within the ATP‐binding pocket of the ALK kinase domain and have been associated with different resistance mutations within ALK itself that arise in response to therapeutic use, particularly in ALK‐fusion positive non‐small cell lung cancer (NSCLC). This patient population has highlighted the importance of considering the relevant ALK TKI to be used for a given ALK mutant variant. In this review, we discuss ALK in neuroblastoma, as well as the use of ALK TKIs and other strategies to inhibit tumor growth. Current efforts combining novel approaches and increasing our understanding of the oncogenic role of ALK in neuroblastoma are aimed at improving the efficacy of ALK TKIs as precision medicine options in the clinic.

Dual-Specificity Phosphatases in Neuroblastoma Cell Growth and Differentiation

Dual-specificity phosphatases (DUSPs) are important regulators of neuronal cell growth and differentiation by targeting proteins essential to neuronal survival in signaling pathways, among which the MAP kinases (MAPKs) stand out. DUSPs include the MAPK phosphatases (MKPs), a family of enzymes that directly dephosphorylate MAPKs, as well as the small-size atypical DUSPs, a group of low molecular-weight enzymes which display more heterogeneous substrate specificity. Neuroblastoma (NB) is a malignancy intimately associated with the course of neuronal and neuroendocrine cell differentiation, and constitutes the source of more common extracranial solid pediatric tumors. Here, we review the current knowledge on the involvement of MKPs and small-size atypical DUSPs in NB cell growth and differentiation, and discuss the potential of DUSPs as predictive biomarkers and therapeutic targets in human NB.