Neuroblastoma: biological insights into a clinical enigma

Use of Optical Genome Mapping to Detect Structural Variants in Neuroblastoma

BACKGROUND

Neuroblastoma is the most common extracranial solid tumour in children, accounting for 15% of paediatric cancer deaths. Multiple genetic abnormalities have been identified as prognostically significant in neuroblastoma patients. Optical genome mapping (OGM) is a novel cytogenetic technique used to detect structural variants, which has not previously been tested in neuroblastoma. We used OGM to identify copy number and structural variants (SVs) in neuroblastoma which may have been missed by standard cytogenetic techniques.

METHODS

Five neuroblastoma cell lines (SH-SY5Y, NBLW, GI-ME-N, NB1691 and SK-N-BE2(C)) and two neuroblastoma tumours were analysed using OGM with the Bionano Saphyr® instrument. The results were analysed using Bionano Access software and compared to previous genetic analyses including G-band karyotyping, FISH (fluorescent in situ hybridisation), single-nucleotide polymorphism (SNP) array and RNA fusion panels for cell lines, and SNP arrays and whole genome sequencing (WGS) for tumours.

RESULTS

OGM detected copy number abnormalities found using previous methods and provided estimates for absolute copy numbers of amplified genes. OGM identified novel SVs, including fusion genes in two cell lines of potential clinical significance.

CONCLUSIONS

OGM can reliably detect clinically significant structural and copy number variations in a single test. OGM may prove to be more time- and cost-effective than current standard cytogenetic techniques for neuroblastoma.

Minimal Residual Disease Detected by the 7NB-mRNAs ddPCR Assay Is Associated with Disease Progression in High-Risk Neuroblastoma Patients: A Prospective Multicenter Observational Study in Japan

High-risk neuroblastoma (HR-NB) patients remain far from obtaining optimal outcomes, with more than 50% relapse/regrowth rate despite current intensive multimodal therapy. This originated from the activation/proliferation of chemoresistant minimal residual disease (MRD). MRD with a significant prognostic was reported by several quantitative PCR (qPCR) or droplet digital PCR (ddPCR) assays quantitating different sets of NB-associated mRNAs (NB-mRNAs). The 7NB-mRNAs ddPCR assay quantitating CRMP1, DBH, DDC, GAP43, ISL1, PHOX2B, and TH mRNAs was reported to outperform other qPCR assays by a retrospective in-house observational study. In the present study, the Japan Children's Cancer Group (JCCG) Neuroblastoma Committee conducted a prospective multicenter observational study aimed at evaluating a prognostic value of MRD in bone marrow (BM-MRD) and peripheral blood (PB-MRD) detected by 7NB-mRNAs ddPCR assay. Between August 2018 and August 2022, 7 HR-NB patients who registered for JCCG clinical trials (JN-H-11 and JN-H-15) were enrolled. A total of 19 BM and 19 PB samples were collected, and 4/15 BM and 4/15 PB samples were classified as progressive disease (PD)/non-PD samples. BM-MRD and PB-MRD estimated area under curve (AUC) of 0.767 and 0.800 with a significant accuracy (AUC > 0.7). The present study validated a prognostic value of BM-MRD obtained by a previous study (AUC 0.723) and revealed the significant accuracy of PB-MRD as well as BM-MRD.

Neuroblastoma Interaction with the Tumour Microenvironment and Its Implications for Treatment and Disease Progression

Neuroblastoma, a paediatric malignancy of the peripheral nervous system, displays a wide range of clinical outcomes, including regression to fatality despite extensive treatment. Neuroblastoma tumours display a complex interplay with their surrounding environment, known as the tumour microenvironment, which may affect disease progression and patient prognosis. This study aimed to dissect the ways in which neuroblastoma biology, treatment, prognosis, progression, and relapse are linked with the extracellular matrix, the dichotomous identities of neuroblastoma, various regulatory proteins and RNA, and extracellular vesicles within the backdrop of the tumour microenvironment. In addition, other aspects, such as immune cell infiltration, therapeutic options including monoclonal antibodies and small molecule inhibitors; and the ways in which these may affect disease progression and immunosuppression within the context of the neuroblastoma tumour microenvironment, are addressed. Such studies may shed light on useful therapeutic targets within the tumour microenvironment that may benefit groups of NB patients. Ultimately, a detailed understanding of these aspects will enable the neuroblastoma scientific community to improve treatment options, patient outcomes, and quality of life.

Gain-of-function MYCN causes a megalencephaly-polydactyly syndrome manifesting mirror phenotypes of Feingold syndrome

MYCN, a member of the MYC proto-oncogene family, regulates cell growth and proliferation. Somatic mutations of MYCN are identified in various tumors, and germline loss-of-function variants are responsible for Feingold syndrome, characterized by microcephaly. In contrast, one megalencephalic patient with a gain-of-function variant in MYCN, p.Thr58Met, has been reported, and additional patients and pathophysiological analysis are required to establish the disease entity. Herein, we report two unrelated megalencephalic patients with polydactyly harboring MYCN variants of p.Pro60Leu and Thr58Met, along with the analysis of gain-of-function and loss-of-function Mycn mouse models. Functional analyses for MYCN-Pro60Leu and MYCN-Thr58Met revealed decreased phosphorylation at Thr58, which reduced protein degradation mediated by FBXW7 ubiquitin ligase. The gain-of-function mouse model recapitulated the human phenotypes of megalencephaly and polydactyly, while brain analyses revealed excess proliferation of intermediate neural precursors during neurogenesis, which we determined to be the pathomechanism underlying megalencephaly. Interestingly, the kidney and female reproductive tract exhibited overt morphological anomalies, possibly as a result of excess proliferation during organogenesis. In conclusion, we confirm an MYCN gain-of-function-induced megalencephaly-polydactyly syndrome, which shows a mirror phenotype of Feingold syndrome, and reveal that MYCN plays a crucial proliferative role, not only in the context of tumorigenesis, but also organogenesis.

Mutational topography reflects clinical neuroblastoma heterogeneity

Neuroblastoma is a pediatric solid tumor characterized by strong clinical heterogeneity. Although clinical risk-defining genomic alterations exist in neuroblastomas, the mutational processes involved in their generation remain largely unclear. By examining the topography and mutational signatures derived from all variant classes, we identified co-occurring mutational footprints, which we termed mutational scenarios. We demonstrate that clinical neuroblastoma heterogeneity is associated with differences in the mutational processes driving these scenarios, linking risk-defining pathognomonic variants to distinct molecular processes. Whereas high-risk MYCN-amplified neuroblastomas were characterized by signs of replication slippage and stress, homologous recombination-associated signatures defined high-risk non-MYCN-amplified patients. Non-high-risk neuroblastomas were marked by footprints of chromosome mis-segregation and TOP1 mutational activity. Furthermore, analysis of subclonal mutations uncovered differential activity of these processes through neuroblastoma evolution. Thus, clinical heterogeneity of neuroblastoma patients can be linked to differences in the mutational processes that are active in their tumors.

MYCN amplification, TERT rearrangements and ATRX mutations in neuroblastoma: clinicopathological correlates- an Indian perspective

BACKGROUND

Neuroblastoma (NB) is the most common extracranial solid tumour in childhood with a diverse clinical presentation and course. The early age of onset, high frequency of metastatic disease at diagnosis and tendency for spontaneous regression in infancy sets it apart from other childhood tumors. This heterogeneity is largely attributed to underlying genetic aberrations which are distinct in low-risk and high-risk NB. To this end, we sought to analyse our NB cases for the molecular alterations and find its correlation with clinical behaviour.

METHODS

NB cases (n = 50) diagnosed over last 7 years were retrospectively analysed for MYCN amplification (fluorescent-in-situ hybridization), TERT rearrangements (qRT-PCR), ATRX mutations (immunohistochemistry). These findings were correlated with demographic profiles, histologic features and clinical outcome.

RESULTS

Age ranged from 1 month to 30 years (mean 2.8 years) with male preponderance. Poorly differentiated subtype constituted the majority (64%), followed by differentiating (28%) and undifferentiated subtype (8%) which were equally distributed across all age groups. MYCN amplification, TERT-mRNA upregulation and ATRX mutations was observed in 30%, 42% and 24%, respectively. Cases with TERT-mRNA upregulation were distributed equally across all histological subtypes while those with ATRX mutations and MYCN amplification were frequent in poorly differentiated NB. ATRX mutation was mutually exclusive of TERT-mRNA upregulation and MYCN amplification. Kaplan-Meier analysis revealed significantly shorter overall and progression-free survival for tumors harboring MYCN amplification and TERT-mRNA upregulation, while that for ATRX mutant tumors was not significant.

CONCLUSIONS

Our results provide data indicating poor clinical outcome in NB carrying MYCN amplification and TERT-mRNA upregulation.

Repurposing disulfiram, an alcohol-abuse drug, in neuroblastoma causes KAT2A downregulation and in vivo activity with a water/oil emulsion

Neuroblastoma, the most common type of pediatric extracranial solid tumor, causes 10% of childhood cancer deaths. Despite intensive multimodal treatment, the outcomes of high-risk neuroblastoma remain poor. We urgently need to develop new therapies with safe long-term toxicity profiles for rapid testing in clinical trials. Drug repurposing is a promising approach to meet these needs. Here, we investigated disulfiram, a safe and successful chronic alcoholism treatment with known anticancer and epigenetic effects. Disulfiram efficiently induced cell cycle arrest and decreased the viability of six human neuroblastoma cell lines at half-maximal inhibitory concentrations up to 20 times lower than its peak clinical plasma level in patients treated for chronic alcoholism. Disulfiram shifted neuroblastoma transcriptome, decreasing MYCN levels and activating neuronal differentiation. Consistently, disulfiram significantly reduced the protein level of lysine acetyltransferase 2A (KAT2A), drastically reducing acetylation of its target residues on histone H3. To investigate disulfiram's anticancer effects in an in vivo model of high-risk neuroblastoma, we developed a disulfiram-loaded emulsion to deliver the highly liposoluble drug. Treatment with the emulsion significantly delayed neuroblastoma progression in mice. These results identify KAT2A as a novel target of disulfiram, which directly impacts neuroblastoma epigenetics and is a promising candidate for repurposing to treat pediatric neuroblastoma.

MYCN Amplifications and Metabolic Rewiring in Neuroblastoma

Cancer is a disease caused by (epi)genomic and gene expression abnormalities and characterized by metabolic phenotypes that are substantially different from the normal phenotypes of the tissues of origin. Metabolic reprogramming is one of the key features of tumors, including those established in the human nervous system. In this work, we emphasize a well-known cancerous genomic alteration: the amplification of MYCN and its downstream effects in neuroblastoma phenotype evolution. Herein, we extend our previous computational biology investigations by conducting an integrative workflow applied to published genomics datasets and comprehensively assess the impact of MYCN amplification in the upregulation of metabolism-related transcription factor (TF)-encoding genes in neuroblastoma cells. The results obtained first emphasized overexpressed TFs, and subsequently those committed in metabolic cellular processes, as validated by gene ontology analyses (GOs) and literature curation. Several genes encoding for those TFs were investigated at the mechanistic and regulatory levels by conducting further omics-based computational biology assessments applied on published ChIP-seq datasets retrieved from MYCN-amplified- and MYCN-enforced-overexpression within in vivo systems of study. Hence, we approached the mechanistic interrelationship between amplified MYCN and overexpression of metabolism-related TFs in neuroblastoma and showed that many are direct targets of MYCN in an amplification-inducible fashion. These results illuminate how MYCN executes its regulatory underpinnings on metabolic processes in neuroblastoma.

Targeting long noncoding RNAs in neuroblastoma: Progress and prospects

Neuroblastoma (NB) is the third most prevalent tumor that mostly influences infants and young children. Although different treatments have been developed for the treatment of NB, high-risk patients have been reported to have low survival rates. Currently, long noncoding RNAs (lncRNAs) have shown an attractive potential in cancer research and a party of investigations have been performed to understand mechanisms underlying tumor development through lncRNA dysregulation. Researchers have just newly initiated to exhibit the involvement of lncRNAs in NB pathogenesis. In this review article, we tried to clarify the point we stand with respect to the involvement of lncRNAs in NB. Moreover, implications for the pathologic roles of lncRNAs in the development of NB have been discussed. It seems that some of these lncRNAs have promising potential to be applied as biomarkers for NB prognosis and treatment.

Role of non-coding RNAs in neuroblastoma

Neuroblastoma is known as the most prevalent extracranial malignancy in childhood with a neural crest origin. It has been widely accepted that non-coding RNAs (ncRNAs) play important roles in many types of cancer, including glioma and gastrointestinal cancers. They may regulate the cancer gene network. According to recent sequencing and profiling studies, ncRNAs genes are deregulated in human cancers via deletion, amplification, abnormal epigenetic, or transcriptional regulation. Disturbances in the expression of ncRNAs may act either as oncogenes or as anti-tumor suppressor genes, and can lead to the induction of cancer hallmarks. ncRNAs can be secreted from tumor cells inside exosomes, where they can be transferred to other cells to affect their function. However, these topics still need more study to clarify their exact roles, so the present review addresses different roles and functions of ncRNAs in neuroblastoma.

Metabolic protein kinase signalling in neuroblastoma

BACKGROUND

Neuroblastoma is a paediatric malignancy of incredibly complex aetiology. Oncogenic protein kinase signalling in neuroblastoma has conventionally focussed on transduction through the well-characterised PI3K/Akt and MAPK pathways, in which the latter has been implicated in treatment resistance. The discovery of the receptor tyrosine kinase ALK as a target of genetic alterations in cases of familial and sporadic neuroblastoma, was a breakthrough in the understanding of the complex genetic heterogeneity of neuroblastoma. However, despite progress in the development of small-molecule inhibitors of ALK, treatment resistance frequently arises and appears to be a feature of the disease. Moreover, since the identification of ALK, several additional protein kinases, including the PIM and Aurora kinases, have emerged not only as drivers of the disease phenotype, but also as promising druggable targets. This is particularly the case for Aurora-A, given its intimate engagement with MYCN, a driver oncogene of aggressive neuroblastoma previously considered 'undruggable.'

SCOPE OF REVIEW

Aided by significant advances in structural biology and a broader understanding of the mechanisms of protein kinase function and regulation, we comprehensively outline the role of protein kinase signalling, emphasising ALK, PIM and Aurora in neuroblastoma, their respective metabolic outputs, and broader implications for targeted therapies.

MAJOR CONCLUSIONS

Despite massively divergent regulatory mechanisms, ALK, PIM and Aurora kinases all obtain significant roles in cellular glycolytic and mitochondrial metabolism and neuroblastoma progression, and in several instances are implicated in treatment resistance. While metabolism of neuroblastoma tends to display hallmarks of the glycolytic "Warburg effect," aggressive, in particular MYCN-amplified tumours, retain functional mitochondrial metabolism, allowing for survival and proliferation under nutrient stress. Future strategies employing specific kinase inhibitors as part of the treatment regimen should consider combinatorial attempts at interfering with tumour metabolism, either through metabolic pathway inhibitors, or by dietary means, with a view to abolish metabolic flexibility that endows cancerous cells with a survival advantage.

Antitumor activity of the investigational B7-H3 antibody-drug conjugate, vobramitamab duocarmazine, in preclinical models of neuroblastoma

INTRODUCTION

B7-H3 is a potential target for pediatric cancers, including neuroblastoma (NB). Vobramitamab duocarmazine (also referred to as MGC018 and herein referred to as vobra duo) is an investigational duocarmycin-based antibody-drug conjugate (ADC) directed against the B7-H3 antigen. It is composed of an anti-B7-H3 humanized IgG1/kappa monoclonal antibody chemically conjugated through a cleavable valine-citrulline linker to a duocarmycin-hydroxybenzamide azaindole (vc-seco-DUBA). Vobra duo has shown preliminary clinical activity in B7-H3-expressing tumors.

METHODS

B7-H3 expression was evaluated by flow-cytometry in a panel of human NB cell lines. Cytotoxicity was evaluated in monolayer and in multicellular tumor spheroid (MCTS) models by the water-soluble tetrazolium salt,MTS, proliferation assay and Cell Titer Glo 3D cell viability assay, respectively. Apoptotic cell death was investigated by annexin V staining. Orthotopic, pseudometastatic, and resected mouse NB models were developed to mimic disease conditions related to primary tumor growth, metastases, and circulating tumor cells with minimal residual disease, respectively.

RESULTS

All human NB cell lines expressed cell surface B7-H3 in a unimodal fashion. Vobra duo was cytotoxic in a dose-dependent and time-dependent manner against all cell lines (IC50 range 5.1-53.9 ng/mL) and NB MCTS (IC50 range 17.8-364 ng/mL). Vobra duo was inactive against a murine NB cell line (NX-S2) that did not express human B7-H3; however, NX-S2 cells were killed in the presence of vobra duo when co-cultured with human B7-H3-expressing cells, demonstrating bystander activity. In orthotopic and pseudometastatic mouse models, weekly intravenous treatments with 1 mg/kg vobra duo for 3 weeks delayed tumor growth compared with animals treated with an irrelevant (anti-CD20) duocarmycin-ADC. Vobra duo treatment for 4 weeks further increased survival in both orthotopic and resected NB models. Vobra duo compared favorably to TOpotecan-TEMozolomide (TOTEM), the standard-of-care therapy for NB relapsed disease, with tumor relapse delayed or arrested by two or three repeated 4-week vobra duo treatments, respectively. Further increased survival was observed in mice treated with vobra duo in combination with TOTEM. Vobra duo treatment was not associated with body weight loss, hematological toxicity, or clinical chemistry abnormalities.

CONCLUSION

Vobra duo exerts relevant antitumor activity in preclinical B7-H3-expressing NB models and represents a potential candidate for clinical translation.

Investigation of the anticancer mechanism of monensin via apoptosis-related factors in SH-SY5Y neuroblastoma cells

Monensin is an ionophore antibiotic that inhibits the growth of cancer cells. The aim of this study was to investigate the apoptosis-mediated anticarcinogenic effects of monensin in SH-SY5Y neuroblastoma cells. The effects of monensin on cell viability, invasion, migration, and colony formation were determined by XTT, matrigel-chamber, wound healing, and colony formation tests, respectively. The effects of monensin on apoptosis were determined by real-time polymerase chain reaction, TUNEL, Western blot, and Annexin V assay. We have shown that monensin suppresses neuroblastoma cell viability, invasion, migration, and colony formation. Moreover, we reported that monensin inhibits cell viability by triggering apoptosis of neuroblastoma cells. Monensin caused apoptosis by increasing caspase-3, 7, 8, and 9 expressions and decreasing Bax and Bcl-2 expressions in neuroblastoma cells. In Annexin V results, the rates of apoptotic cells were found to be 9.66 ± 0.01% (p < 0.001), 29.28 ± 0.88% (p < 0.01), and 62.55 ± 2.36% (p < 0.01) in the 8, 16, and 32 μM monensin groups, respectively. In TUNEL results, these values were, respectively; 35 ± 2% (p < 0.001), 34 ± 0.57% (p < 0.001), and 75 ± 2.51% (p < 0.001). Our results suggest that monensin may be a safe and effective therapeutic candidate for treating pediatric neuroblastoma.

Adaptation of the Th-MYCN Mouse Model of Neuroblastoma for Evaluation of Disseminated Disease

High-risk neuroblastoma remains a profound clinical challenge that requires eradication of neuroblastoma cells from a variety of organ sites, including bone marrow, liver, and CNS, to achieve a cure. While preclinical modeling is a powerful tool for the development of novel cancer therapies, the lack of widely available models of metastatic neuroblastoma represents a significant barrier to the development of effective treatment strategies. To address this need, we report a novel luciferase-expressing derivative of the widely used Th-MYCN mouse. While our model recapitulates the non-metastatic neuroblastoma development seen in the parental transgenic strain, transplantation of primary tumor cells from disease-bearing mice enables longitudinal monitoring of neuroblastoma growth at distinct sites in immune-deficient or immune-competent recipients. The transplanted tumors retain GD2 expression through many rounds of serial transplantation and are sensitive to GD2-targeted immune therapy. With more diverse tissue localization than is seen with human cell line-derived xenografts, this novel model for high-risk neuroblastoma could contribute to the optimization of immune-based treatments for this deadly disease.

Preclinical Models of Neuroblastoma-Current Status and Perspectives

Preclinical in vitro and in vivo models remain indispensable tools in cancer research. These classic models, including two- and three-dimensional cell culture techniques and animal models, are crucial for basic and translational studies. However, each model has its own limitations and typically does not fully recapitulate the course of the human disease. Therefore, there is an urgent need for the development of novel, advanced systems that can allow for efficient evaluation of the mechanisms underlying cancer development and progression, more accurately reflect the disease pathophysiology and complexity, and effectively inform therapeutic decisions for patients. Preclinical models are especially important for rare cancers, such as neuroblastoma, where the availability of patient-derived specimens that could be used for potential therapy evaluation and screening is limited. Neuroblastoma modeling is further complicated by the disease heterogeneity. In this review, we present the current status of preclinical models for neuroblastoma research, discuss their development and characteristics emphasizing strengths and limitations, and describe the necessity of the development of novel, more advanced and clinically relevant approaches.

Tunable plasmonic tweezers based on graphene nano-taper for nano-bio-particles manipulation: numerical study

We take advantage of graphene nano-taper plasmons to design tunable plasmonic tweezers for neuroblastoma extracellular vesicles manipulation. It consists of Si/SiO₂/Graphene stack topped by a microfluidic chamber. Using plasmons of isosceles-triangle-shaped graphene nano-taper with a resonance frequency of 6.25 THz, the proposed device can efficiently trap the nanoparticles. The plasmons of graphene nano-taper generate a large field intensity in the deep sub-wavelength area around the vertices of the triangle. We show that by engineering the dimensions of the graphene nano-taper and an appropriate choice of its Fermi energy, the desired near-field gradient force for trapping can be generated under relatively low-intensity illumination of the THz source when the nanoparticles are placed near the front vertex of the nano-taper. Our results show that the designed system with graphene nano-taper of L = 1200 nm length and W = 600 nm base size and THz source intensity of I = 2 mW/µm², can trap polystyrene nanoparticles with diameters of D = 140, 73, and 54 nm, and with trap stiffnesses of k_y = 9.9 fN/nm, k_y = 23.77 fN/nm, and k_y = 35.51 fN/nm at Fermi energies of E_f = 0.4, 0.5, and 0.6 eV, respectively. It is well known that the plasmonic tweezer as a high-precision and non-contact means of control has potential applications in biology. Our investigations demonstrate that the proposed tweezing device with L = 1200 nm, W = 600 nm, and E_f = 0.6 eV can be utilized to manipulate the nano-bio-specimens. So that, at the given source intensity, it can trap the neuroblastoma extracellular vesicles, which are released by neuroblastoma cells and play an important role in modulating the function of neuroblastoma cells and other cell populations, as small as 88 nm at the front tip of isosceles-triangle-shaped graphene nano-taper. The trap stiffness for the given neuroblastoma extracellular vesicle is obtained as k_y = 17.92 fN/nm.

Targeting macrophage Syk enhances responses to immune checkpoint blockade and radiotherapy in high-risk neuroblastoma

Background

Neuroblastoma (NB) is considered an immunologically cold tumor and is usually less responsive to immune checkpoint blockade (ICB). Tumor-associated macrophages (TAMs) are highly infiltrated in NB tumors and promote immune escape and resistance to ICB. Hence therapeutic strategies targeting immunosuppressive TAMs can improve responses to ICB in NB. We recently discovered that spleen tyrosine kinase (Syk) reprograms TAMs toward an immunostimulatory phenotype and enhances T-cell responses in the lung adenocarcinoma model. Here we investigated if Syk is an immune-oncology target in NB and tested whether a novel immunotherapeutic approach utilizing Syk inhibitor together with radiation and ICB could provide a durable anti-tumor immune response in an MYCN amplified murine model of NB.

Methods

Myeloid Syk KO mice and syngeneic MYCN-amplified cell lines were used to elucidate the effect of myeloid Syk on the NB tumor microenvironment (TME). In addition, the effect of Syk inhibitor, R788, on anti-tumor immunity alone or in combination with anti-PDL1 mAb and radiation was also determined in murine NB models. The underlying mechanism of action of this novel therapeutic combination was also investigated.

Results

Herein, we report that Syk is a marker of NB-associated macrophages and plays a crucial role in promoting immunosuppression in the NB TME. We found that the blockade of Syk in NB-bearing mice markedly impairs tumor growth. This effect is facilitated by macrophages that become immunogenic in the absence of Syk, skewing the suppressive TME towards immunostimulation and activating anti-tumor immune responses. Moreover, combining FDA-approved Syk inhibitor, R788 (fostamatinib) along with anti-PDL1 mAb provides a synergistic effect leading to complete tumor regression and durable anti-tumor immunity in mice bearing small tumors (50 mm3) but not larger tumors (250 mm3). However, combining radiation to R788 and anti-PDL1 mAb prolongs the survival of mice bearing large NB9464 tumors.

Conclusion

Collectively, our findings demonstrate the central role of macrophage Syk in NB progression and demonstrate that Syk blockade can "reeducate" TAMs towards immunostimulatory phenotype, leading to enhanced T cell responses. These findings further support the clinical evaluation of fostamatinib alone or with radiation and ICB, as a novel therapeutic intervention in neuroblastoma.

Prognostic value of xenograft engraftment in patients with metastatic high-risk neuroblastoma

BACKGROUND

Successful engraftment of human cancer biopsies in immunodeficient mice correlates with the poor prognosis of patients. This was reported 30 years ago for children with neuroblastoma, but the standard of care treatment evolved significantly during the last 15 years, leading to improved survival of these patients. Here, we evaluated the association of patient-derived xenograft (PDX) engraftment and prognosis in patients receiving up-to-date treatments for cancers classified as metastatic (stage M) high-risk neuroblastoma (HR-NB) by the International Neuroblastoma Risk Group Staging System (INRGSS).

METHODS

We obtained biopsies from patients with stage M HR-NB. We inoculated biopsy fragments subcutaneously in mice. We studied the association of PDX engraftment with event-free survival (EFS) and overall survival (OS) of patients.

RESULTS

Since 2009, we established 17 PDX from 97 samples of 66 patients with stage M HR-NB, with a follow-up of at least two years. Factors associated with higher probability of engraftment were the death as outcome (p = .0006) and the amplification of the gene MYCN in tumors (p = .0271). Patients whose biopsies established a PDX had significantly shorter EFS and OS (p = .0039 and .0002, respectively) than patients whose samples did not engraft. The association of PDX engraftment and OS was significant in patients without MYCN amplification (p = .0041), but not in patients with MYCN amplification (p = .2707).

CONCLUSION

Positive PDX engraftment is a factor related to poor prognosis and fatal outcome in patients with stage M HR-NB treated with up-to-date therapies.

miR-210-3p enriched extracellular vesicles from hypoxic neuroblastoma cells stimulate migration and invasion of target cells

BACKGROUND

Tumor hypoxia stimulates release of extracellular vesicles (EVs) that facilitate short- and long-range intercellular communication and metastatization. Albeit hypoxia and EVs release are known features of Neuroblastoma (NB), a metastasis-prone childhood malignancy of the sympathetic nervous system, whether hypoxic EVs can facilitate NB dissemination is unclear.

METHODS

Here we isolated and characterized EVs from normoxic and hypoxic NB cell culture supernatants and performed microRNA (miRNA) cargo analysis to identify key mediators of EVs biological effects. We then validated if EVs promote pro-metastatic features both in vitro and in an in vivo zebrafish model.

RESULTS

EVs from NB cells cultured at different oxygen tensions did not differ for type and abundance of surface markers nor for biophysical properties. However, EVs derived from hypoxic NB cells (hEVs) were more potent than their normoxic counterpart in inducing NB cells migration and colony formation. miR-210-3p was the most abundant miRNA in the cargo of hEVs; mechanistically, overexpression of miR-210-3p in normoxic EVs conferred them pro-metastatic features, whereas miR-210-3p silencing suppressed the metastatic ability of hypoxic EVs both in vitro and in vivo.

CONCLUSION

Our data identify a role for hypoxic EVs and their miR-210-3p cargo enrichment in the cellular and microenvironmental changes favoring NB dissemination.

68Ga-DOTATATE PET in Restaging and Response to Therapy in Neuroblastoma: A Case Series and a Mini Review

⁶⁸Ga-DOTATATE PET/CT is widely used for the evaluation of neuroendocrine tumors. Some reports exist on its use in the management of neuroblastoma. Building on the prior reports as well as our previous experience in using this technique for initial staging, we propose to describe its practical benefits in restaging and response to therapy. We describe different aspects including supply logistics, preparation, spatial resolution, and other practical applications. Methods: We reviewed the medical records for 8 patients who were evaluated with ⁶⁸Ga-DOTATATE PET/CT at our institution over 2 y. A note was made of the patient and disease characteristics and the indication for PET imaging, and the results were retrospectively analyzed for feasibility, logistics, radiation exposure, and utility in answering the clinical question. Results: Eight children (5 girls and 3 boys; age range, 4-60 mo; median age, 30 mo) diagnosed with neuroblastoma were imaged with ⁶⁸Ga-DOTATATE PET/CT and 5 with ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG) SPECT/CT over 2 y. Three ⁶⁸Ga-DOTATATE PET scans were done for staging, 10 for response evaluation, and 2 for restaging. ⁶⁸Ga-DOTATATE PET accurately identified neuroblastoma lesions suspected or seen on anatomic imaging. It has been shown to be more specific and more sensitive than ¹²³I-MIBG and at times also MRI. It had better spatial and contrast resolution than ¹²³I-MIBG. ⁶⁸Ga-DOTATATE PET was better than ¹²³I-MIBG SPECT/CT, CT, and MRI in the detection of early progression and viable tumor delineation for response assessment, as well as in target volume definition for external-beam radiotherapy and proton-beam radiotherapy. ⁶⁸Ga-DOTATATE PET was also better at assessing bony and bone marrow disease changes with time. Conclusion: ⁶⁸Ga-DOTATATE PET/CT offers added value and a superior edge to other imaging modalities in restaging and response assessment in neuroblastoma patients. Further multicenter evaluations in larger cohorts are needed.

Biological Insight and Recent Advancement in the Treatment of Neuroblastoma

One of the most frequent solid tumors in children is neuroblastoma, which has a variety of clinical behaviors that are mostly influenced by the biology of the tumor. Unique characteristics of neuroblastoma includes its early age of onset, its propensity for spontaneous tumor regression in newborns, and its high prevalence of metastatic disease at diagnosis in individuals older than 1 year of age. Immunotherapeutic techniques have been added to the previously enlisted chemotherapeutic treatments as therapeutic choices. A groundbreaking new treatment for hematological malignancies is adoptive cell therapy, specifically chimeric antigen receptor (CAR) T cell therapy. However, due to the immunosuppressive nature of the tumor microenvironment (TME) of neuroblastoma tumor, this treatment approach faces difficulties. Numerous tumor-associated genes and antigens, including the MYCN proto-oncogene (MYCN) and disialoganglioside (GD2) surface antigen, have been found by the molecular analysis of neuroblastoma cells. The MYCN gene and GD2 are two of the most useful immunotherapy findings for neuroblastoma. The tumor cells devise numerous methods to evade immune identification or modify the activity of immune cells. In addition to addressing the difficulties and potential advancements of immunotherapies for neuroblastoma, this review attempts to identify important immunological actors and biological pathways involved in the dynamic interaction between the TME and immune system.

Reversible transitions between noradrenergic and mesenchymal tumor identities define cell plasticity in neuroblastoma

Noradrenergic and mesenchymal identities have been characterized in neuroblastoma cell lines according to their epigenetic landscapes and core regulatory circuitries. However, their relationship and relative contribution in patient tumors remain poorly defined. We now document spontaneous and reversible plasticity between the two identities, associated with epigenetic reprogramming, in several neuroblastoma models. Interestingly, xenografts with cells from each identity eventually harbor a noradrenergic phenotype suggesting that the microenvironment provides a powerful pressure towards this phenotype. Accordingly, such a noradrenergic cell identity is systematically observed in single-cell RNA-seq of 18 tumor biopsies and 15 PDX models. Yet, a subpopulation of these noradrenergic tumor cells presents with mesenchymal features that are shared with plasticity models, indicating that the plasticity described in these models has relevance in neuroblastoma patients. This work therefore emphasizes that intrinsic plasticity properties of neuroblastoma cells are dependent upon external cues of the environment to drive cell identity.

The Chromatin Remodeler ATRX: Role and Mechanism in Biology and Cancer

The alpha-thalassemia mental retardation X-linked (ATRX) syndrome protein is a chromatin remodeling protein that primarily promotes the deposit of H3.3 histone variants in the telomere area. ATRX mutations not only cause ATRX syndrome but also influence development and promote cancer. The primary molecular characteristics of ATRX, including its molecular structures and normal and malignant biological roles, are reviewed in this article. We discuss the role of ATRX in its interactions with the histone variant H3.3, chromatin remodeling, DNA damage response, replication stress, and cancers, particularly gliomas, neuroblastomas, and pancreatic neuroendocrine tumors. ATRX is implicated in several important cellular processes and serves a crucial function in regulating gene expression and genomic integrity throughout embryogenesis. However, the nature of its involvement in the growth and development of cancer remains unknown. As mechanistic and molecular investigations on ATRX disclose its essential functions in cancer, customized therapies targeting ATRX will become accessible.

ATM depletion induces proteasomal degradation of FANCD2 and sensitizes neuroblastoma cells to PARP inhibitors

BACKGROUND

Genomic alterations, including loss of function in chromosome band 11q22-23, are frequently observed in neuroblastoma, which is the most common extracranial childhood tumour. In neuroblastoma, ATM, a DNA damage response-associated gene located on 11q22-23, has been linked to tumorigenicity. Genetic changes in ATM are heterozygous in most tumours. However, it is unclear how ATM is associated with tumorigenesis and cancer aggressiveness.

METHODS

To elucidate its molecular mechanism of action, we established ATM-inactivated NGP and CHP-134 neuroblastoma cell lines using CRISPR/Cas9 genome editing. The knock out cells were rigorously characterized by analyzing proliferation, colony forming abilities and responses to PARP inhibitor (Olaparib). Western blot analyses were performed to detect different protein expression related to DNA repair pathway. ShRNA lentiviral vectors were used to knockdown ATM expression in SK-N-AS and SK-N-SH neuroblastoma cell lines. ATM knock out cells were stably transfected with FANCD2 expression plasmid to over-expressed the FANCD2. Moreover, knock out cells were treated with proteasome inhibitor MG132 to determine the protein stability of FANCD2. FANCD2, RAD51 and γH2AX protein expressions were determined by Immunofluorescence microscopy.

RESULTS

Haploinsufficient ATM resulted in increased proliferation (p < 0.01) and cell survival following PARP inhibitor (olaparib) treatment. However, complete ATM knockout decreased proliferation (p < 0.01) and promoted cell susceptibility to olaparib (p < 0.01). Complete loss of ATM suppressed the expression of DNA repair-associated molecules FANCD2 and RAD51 and induced DNA damage in neuroblastoma cells. A marked downregulation of FANCD2 expression was also observed in shRNA-mediated ATM-knockdown neuroblastoma cells. Inhibitor experiments demonstrated that the degradation of FANCD2 was regulated at the protein level through the ubiquitin-proteasome pathway. Reintroduction of FANCD2 expression is sufficient to reverse decreased proliferation mediated by ATM depletion.

CONCLUSIONS

Our study revealed the molecular mechanism underlying ATM heterozygosity in neuroblastomas and elucidated that ATM inactivation enhances the susceptibility of neuroblastoma cells to olaparib treatment. These findings might be useful in the treatment of high-risk NB patients showing ATM zygosity and aggressive cancer progression in future.

Lipid Metabolic Reprogramming in Embryonal Neoplasms with MYCN Amplification

Tumor cells reprogram their metabolism, including glucose, glutamine, nucleotide, lipid, and amino acids to meet their enhanced energy demands, redox balance, and requirement of biosynthetic substrates for uncontrolled cell proliferation. Altered lipid metabolism in cancer provides lipids for rapid membrane biogenesis, generates the energy required for unrestricted cell proliferation, and some of the lipids act as signaling pathway mediators. In this review, we focus on the role of lipid metabolism in embryonal neoplasms with MYCN dysregulation. We specifically review lipid metabolic reactions in neuroblastoma, retinoblastoma, medulloblastoma, Wilms tumor, and rhabdomyosarcoma and the possibility of targeting lipid metabolism. Additionally, the regulation of lipid metabolism by the MYCN oncogene is discussed.

Exposure to nitrosatable drugs during pregnancy and childhood cancer: A matched case-control study in Denmark, 1996-2016

BACKGROUND

Nitrosatable drugs can be synthesized to N-nitroso compounds in human stomach. In a pregnant woman, N-nitroso compounds can be translocated to the fetus through the placenta. Maternal exposure of nitrosatable compounds during pregnancy has been associated with childhood brain tumors and leukemia. However, few studies have investigated an association between nitrosatable drug exposure during pregnancy and childhood cancer. We examined if maternal prescriptions of nitrosatable drugs received during pregnancy are associated with childhood cancer.

METHODS

A matched case-control study was conducted using Danish nationwide registry data from 1995 to 2016. Each childhood cancer case was matched with twenty-five controls. Maternal exposure of nitrosatable drugs during pregnancy was identified from the Danish National Prescription Register. A multivariable conditional logistic regression model was used to estimate adjusted odds ratios (adj.OR) with 95% confidence intervals (CI) for each childhood cancer type.

RESULTS

Maternal prescriptions of nitrosatable drugs positively associate with central nervous system tumors (adj.OR = 1.25; 95% CI = 1.04-1.51) and neuroblastoma (adj.OR = 1.96; 95% CI = 1.34-2.85) in offspring. We also observed a positive association between perinatal exposure of nitrosatable drugs and acute lymphoblastic leukemia (adj.OR = 1.31; 95% CI = 1.07-1.59), however, it appeared to be due to confounding by indication, i.e., maternal infections.

CONCLUSION

Nitrosatable drug use during pregnancy potentially increased risk of central nervous system tumors and neuroblastoma. While a positive association between maternal prescriptions of nitrosatable drugs and acute lymphoblastic leukemia should be interpreted cautiously because of confounding by indication.

Nectin2 influences cell apoptosis by regulating ANXA2 expression in neuroblastoma

Neuroblastoma (NB) is a pediatric cancer of the peripheral sympathetic nervous system and represents the most frequent solid malignancy in infants. Nectin2 belongs to the immunoglobulin superfamily and has been shown to play a role in tumorigenesis. In the current study, we demonstrate that serum Nectin2 level is increased in NB patients compared with that in healthy controls and Nectin2 level is correlated with neuroblastoma international neuroblastoma staging system (INSS) classification. There is a positive correlation between Nectin2 level and shorter overall survival in NB patients. Knockdown of Nectin2 reduces the migration of SH-SY5Y and SK-N-BE2 cells and induces their apoptosis and cell cycle arrest. RNA-seq analysis demonstrates that Nectin2 knockdown affects the expressions of 258 genes, including 240 that are upregulated and 18 that are downregulated compared with negative controls. qRT-PCR and western blot analysis confirm that ANXA2 expression is decreased in Nectin2-knockdown SH-SY5Y cells, consistent with the RNA-seq results. ANXA2 overexpression rescues the percentage of apoptotic NB cells induced by Nectin2 knockdown and compensates for the impact of Nectin2 knockdown on cleaved caspase3 and bax expressions. In addition, western blot analysis results show that ANXA2 overexpression rescues the effect of Nectin2 knockdown on MMP2 and MMP9 expressions. The current data highlight the importance of Nectin2 in NB progression and the potential of Nectin2 as a novel candidate target for gene therapy.

Metastasis in Neuroblastoma and Its Link to Autophagy

Neuroblastoma is a paediatric malignancy originating from the neural crest that commonly occurs in the abdomen and adrenal gland, leading to cancer-related deaths in children. Distant metastasis can be encountered at diagnosis in greater than half of these neuroblastoma patients. Autophagy, a self-degradative process, plays a key role in stress-related responses and the survival of cells and has been studied in neuroblastoma. Accordingly, in the early stages of metastasis, autophagy may suppress cancer cell invasion and migration, while its role may be reversed in later stages, and it may facilitate metastasis by enhancing cancer cell survival. To that end, a body of literature has revealed the mechanistic link between autophagy and metastasis in neuroblastoma in multiple steps of the metastatic cascade, including cancer cell invasion and migration, anoikis resistance, cancer cell dormancy, micrometastasis, and metastatic outbreak. This review aims to take a step forward and discuss the significance of multiple molecular players and compounds that may link autophagy to metastasis and map their function to various metastatic steps in neuroblastoma.

Identification of a cytotoxic factor from a non-pigmented entomopathogenic Serratia marcescens isolate toxic towards human carcinoma cell lines

It has been reported that cell-free culture broths and some proteins from pigmented and non-pigmented Serratia spp. are cytotoxic towards cancerous and non-cancerous human cell lines. Looking for new molecules toxic against human cancerous cells but harmless towards normal human cells, the aim of this work was (a) to determine whether cell-free broths from the entomopathogenic non-pigmented S. marcescens 81 (Sm81), S. marcescens 89 (Sm89) and S. entomophila (SeMor4.1) presented cytotoxic activity towards human carcinoma cell lines; (b) to identify and purify the associated cytotoxic factor(s) and (c) to evaluate whether the cytotoxic factor(s) was cytotoxic towards non-cancerous human cells. This research was focussed on the observed morphology changes and the proportion of remaining viable cells after incubation in the presence of cell-free culture broths from the Serratia spp isolates to evaluate cytotoxic activity. The results showed that broths from both S. marcescens isolates presented cytotoxic activity and induced cytopathic-like effects on the human neuroblastoma CHP-212 and the breast cancer MDA-MB-231 cells. Slight cytotoxicity was observed in the SeMor4.1 broth. A serralysin-like protein of 50 kDa was identified in Sm81 broth as responsible for cytotoxic activity after purification by ammonium sulphate precipitation and ion-exchange chromatography followed by tandem-mass spectrometry (LC-MS/MS). The serralysin-like protein was toxic against CHP-212 (neuroblastoma), SiHa (human cervical carcinoma) and D-54 (human glioblastoma) cell lines in a dose-dependent manner and showed no cytotoxic activity in primary cultures of normal non-cancerous human keratinocytes and fibroblasts. Therefore, this protein should be evaluated for a potential use as an anticancer agent.

Interaction between tumor cell TNFR2 and monocyte membrane-bound TNF-α triggers tumorigenic inflammation in neuroblastoma

BACKGROUND

Tumor progression and resistance to therapy in children with neuroblastoma (NB), a common childhood cancer, are often associated with infiltration of monocytes and macrophages that produce inflammatory cytokines. However, the mechanism by which tumor-supportive inflammation is initiated and propagated remains unknown. Here, we describe a novel protumorigenic circuit between NB cells and monocytes that is triggered and sustained by tumor necrosis factor alpha (TNF-α).

METHODS

We used NB knockouts (KOs) of TNF-α and TNFRSF1A mRNA (TNFR1)/TNFRSF1B mRNA (TNFR2) and TNF-α protease inbitor (TAPI), a drug that modulates TNF-α isoform expression, to assess the role of each component in monocyte-associated protumorigenic inflammation. Additionally, we employed NB-monocyte cocultures and treated these with clinical-grade etanercept, an Fc-TNFR2 fusion protein, to neutralize signaling by both membrane-bound (m) and soluble (s)TNF-α isoforms. Further, we treated NOD/SCID/IL2Rγ(null) mice carrying subcutaneous NB/human monocyte xenografts with etanercept and evaluated the impact on tumor growth and angiogenesis. Gene set enrichment analysis (GSEA) was used to determine whether TNF-α signaling correlates with clinical outcomes in patients with NB.

RESULTS

We found that NB expression of TNFR2 and monocyte membrane-bound tumor necrosis factor alpha is required for monocyte activation and interleukin (IL)-6 production, while NB TNFR1 and monocyte soluble TNF-α are required for NB nuclear factor kappa B subunit 1 (NF-κB) activation. Treatment of NB-monocyte cocultures with clinical-grade etanercept completely abrogated release of IL-6, granulocyte colony-stimulating factor (G-CSF), IL-1α, and IL-1β and eliminated monocyte-induced enhancement of NB cell proliferation in vitro. Furthermore, etanercept treatment inhibited tumor growth, ablated tumor angiogenesis, and suppressed oncogenic signaling in mice with subcutaneous NB/human monocyte xenografts. Finally, GSEA revealed significant enrichment for TNF-α signaling in patients with NB that relapsed.

CONCLUSIONS

We have described a novel mechanism of tumor-promoting inflammation in NB that is strongly associated with patient outcome and could be targeted with therapy.

NSUN2 gene rs13181449 C>T polymorphism reduces neuroblastoma risk

Neuroblastoma is the most common tumor in infants. RNA m5C modification regulates the survival, differentiation, and migration of cells affecting RNA function. However, the effects of the m5C modification methyltransferase gene NSUN2 polymorphism on neuroblastoma susceptibility have not been reported. TaqMan method was used to determine genotypes of four NSUN2 polymorphisms (rs4702373 C>T, rs13181449 C>T, rs166049 T>G, and rs8192120 A>C) in 402 patients with neuroblastoma and 473 cancer-free controls from Jiangsu province, China. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the association of NSUN2 polymorphisms with neuroblastoma susceptibility. The association was also further assessed in subgroups stratified by age, sex, tumor origin, and stage. GTEx was used to analyze the effect of these polymorphisms on NSUN2 expression. We found the rs13181449 C>T was significantly associated with reduced neuroblastoma risk (CT vs. CC: adjusted OR = 0.68, 95% CI = 0.51-0.92, P = 0.012; CT/TT vs. CC: adjusted OR = 0.70, 95% CI = 0.53-0.92, P = 0.010). Compared with 0-2 protective genotypes, those with 3-4 protective genotypes could significantly reduce the neuroblastoma risk (adjusted OR = 0.68, 95% CI = 0.52 to 0.90, P = 0.006). Stratification analysis showed that the protective effect of rs13181449 polymorphism remained significant in children with age >18 months, boys, and those with early INSS stages. Moreover, children with more protective genotypes in the same subgroups also exhibited significantly reduced neuroblastoma risk. GTEx analysis showed that the rs13181449 T genotype was related with decreased NSUN2 gene expression. In conclusions, NSUN2 rs13181449 polymorphism is associated with decreased neuroblastoma risk, and the underlying mechanism in neuroblastoma needs further study.

Comparison among Neuroblastoma Stages Suggests the Involvement of Mitochondria in Tumor Progression

Neuroblastoma (NB) is the most common extracranial tumor of early childhood and accounts for 15% of all pediatric cancer mortalities. However, the precise pathways and genes underlying its progression are unknown. Therefore, we performed a differential gene expression analysis of neuroblastoma stage 1 and stage 4 + 4S to discover biological processes associated with NB progression. From this preliminary analysis, we found that NB samples (stage 4 + 4S) are characterized by altered expression of some proteins involved in mitochondria function and mitochondria-ER contact sites (MERCS). Although further analyses remain necessary, this review may provide new hints to better understand NB molecular etiopathogenesis, by suggesting that MERCS alterations could be involved in the progression of NB.

TRAF4 Silencing Induces Cell Apoptosis and Improves Retinoic Acid Sensitivity in Human Neuroblastoma

Neuroblastoma (NB) is a pediatric malignancy that arises in the peripheral nervous system, and the prognosis in the high-risk group remains dismal, despite the breakthroughs in multidisciplinary treatments. The oral treatment with 13-cis-retinoic acid (RA) after high-dose chemotherapy and stem cell transplant has been proven to reduce the incidence of tumor relapse in children with high-risk neuroblastoma. However, many patients still have tumors relapsed following retinoid therapy, highlighting the need for the identification of resistant factors and the development of more effective treatments. Herein, we sought to investigate the potential oncogenic roles of the tumor necrosis factor (TNF) receptor-associated factor (TRAF) family in neuroblastoma and explore the correlation between TRAFs and retinoic acid sensitivity. We discovered that all TRAFs were efficiently expressed in neuroblastoma, but TRAF4, in particular, was found to be strongly expressed. The high expression of TRAF4 was associated with a poor prognosis in human neuroblastoma. The inhibition of TRAF4, rather than other TRAFs, improved retinoic acid sensitivity in two human neuroblastoma cell lines, SH-SY5Y and SK-N-AS cells. Further in vitro studies indicated that TRAF4 suppression induced retinoic acid-induced cell apoptosis in neuroblastoma cells, probably by upregulating the expression of Caspase 9 and AP1 while downregulating Bcl-2, Survivin, and IRF-1. Notably, the improved anti-tumor effects from the combination of TRAF4 knockdown and retinoic acid were confirmed in vivo using the SK-N-AS human neuroblastoma xenograft model. In conclusion, the highly expressed TRAF4 might be implicated in developing resistance to retinoic acid treatment in neuroblastoma, and the combination therapy with retinoic acid and TRAF4 inhibition may offer significant therapeutic advantages in the treatment of relapsed neuroblastoma.

Recent advances in the roles of exosomal microRNAs in neuroblastoma

Exosomal miRNAs (exo-miRs), universally found in biofluids, tissues, and/or conditioned medium of the cell cultures play a significant role in cell - cell communication, thus driving cancer progression and metastasis. Very few studies have explored the role of exo-miRs in the progression of children’s cancer - neuroblastoma. In this mini review, I briefly summarize the existing literature on the role of exo-miRs in the pathogenesis of neuroblastoma.

Recent advances in the roles of exosomal microRNAs in neuroblastoma

Exosomal miRNAs (exo-miRs), universally found in biofluids, tissues, and/or conditioned medium of the cell cultures play a significant role in cell - cell communication, thus driving cancer progression and metastasis. Very few studies have explored the role of exo-miRs in the progression of children's cancer - neuroblastoma. In this mini review, I briefly summarize the existing literature on the role of exo-miRs in the pathogenesis of neuroblastoma.

GATA3 positively regulates PAR1 to facilitate in vitro disease progression and decrease cisplatin sensitivity in neuroblastoma via inhibiting the hippo pathway

GATA binding protein 3 (GATA3) is reported to critically involved in the pathogenesis of neuroblastoma (NB). This study investigated the specific role and mechanism of GATA3 in NB progression. JASPAR was utilized to predict GATA3's downstream targets, whose binding relation with GATA3 was inspected by a dual-luciferase reporter assay. NB cell lines underwent transfection of GATA3/protease-activated receptor 1 (PAR1) overexpression plasmids or shGATA3, followed by cisplatin treatment. NB cell sensitivity to cisplatin, viability, migration, invasion, cell cycle progression and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, wound healing assay, transwell assay and flow cytometry, respectively. Expressions of GATA3, PAR1, epithelial-mesenchymal transition-related molecules (N-Cadherin and Vimentin), hippo pathway-related molecules (mammalian Ste20-like kinase (Mst)1, Mst2, Mps one binding (Mob) 1, phosphorylated (p)-Mob1, Yes-associated protein (YAP) and p-YAP) in NB tissues and cell lines were assessed by western blot or qRT-PCR. GATA3 expression was increased in NB tissues and cells. GATA3 overexpression increased NB cell viability, promoted migration, invasion, and cell cycle progression, increased the expressions of N-Cadherin, Vimentin and YAP, decreased the expressions of Mst1, Mst2, Mob1, p-Mob1, p-YAP and the ratio of p-YAP to YAP, and attenuated cisplatin-induce cell apoptosis, which GATA3 knockdown induced the opposite effect. GATA3 directly targeted PAR1, whose overexpression increased NB cell viability, inhibited the hippo pathway, and attenuated cisplatin-induce cell apoptosis, and reversed GATA3 knockdown-induced effect on these aspects. GATA3 positively regulates PAR1 to facilitate in-vitro disease progression and decrease cisplatin sensitivity in NB via inhibiting the hippo pathway.

Machine learning methods revealed the roles of immune-metabolism related genes in immune infiltration, stemness, and prognosis of neuroblastoma

BACKGROUND

Immunometabolism plays an important role in neuroblastoma (NB). However, the mechanism of immune-metabolism related genes (IMRGs) in NB remains unclear. This study aimed to explore the effects of IMRGs on the prognosis, immune infiltration and stemness of patients with NB using machine learning methods.

METHODS

R software (v4.2.1) was used to identify the differentially expressed IMRGs, and machine learning algorithm was used to screen the prognostic genes from IMRGs. Then we constructed a prognostic model and calculated the risk scores. The NB patients were grouped according to the prognosis scores. In addition, the genes most associated with the immune infiltration and stemness of NB were analyzed by weighted gene co-expression network analysis (WGCNA).

RESULTS

There were 89 differentially expressed IMRGs between the MYCN amplification and the MYCN non-amplification group, among which CNR1, GNAI1, GLDC and ABCC4 were selected by machine learning algorithm to construct the prognosis model due to their better prediction effect. Both the K-M survival curve and the 5-year Receiver operating characteristic (ROC) curve indicated that the prognosis model could predict the prognosis of NB patients, and there was significant difference in immune infiltration between the two groups according to the median of risk score.

CONCLUSIONS

We verified the effects of IMRGs on the prognosis, immune infiltration and stemness of NB. These findings could provide help for predicting prognosis and developing immunotherapy in NB.

Macrophage infiltration promotes regrowth in MYCN-amplified neuroblastoma after chemotherapy

Despite aggressive treatment, the 5-year event-free survival rate for children with high-risk neuroblastoma is <50%. While most high-risk neuroblastoma patients initially respond to treatment, often with complete clinical remission, many eventually relapse with therapy-resistant tumors. Novel therapeutic alternatives that prevent the recurrence of therapy-resistant tumors are urgently needed. To understand the adaptation of neuroblastoma under therapy, we analyzed the transcriptomic landscape in 46 clinical tumor samples collected before (PRE) or after (POST) treatment from 22 neuroblastoma patients. RNA sequencing revealed that many of the top-upregulated biological processes in POST MYCN amplified (MNA⁺) tumors compared to PRE MNA⁺ tumors were immune-related, and there was a significant increase in numerous genes associated with macrophages. The infiltration of macrophages was corroborated by immunohistochemistry and spatial digital protein profiling. Moreover, POST MNA⁺ tumor cells were more immunogenic compared to PRE MNA⁺ tumor cells. To find support for the macrophage-induced outgrowth of certain subpopulations of immunogenic tumor cells following treatment, we examined the genetic landscape in multiple clinical PRE and POST tumor samples from nine neuroblastoma patients revealing a significant correlation between an increased amount of copy number aberrations (CNA) and macrophage infiltration in POST MNA⁺ tumor samples. Using an in vivo neuroblastoma patient-derived xenograft (PDX) chemotherapy model, we further show that inhibition of macrophage recruitment with anti-CSF1R treatment prevents the regrowth of MNA⁺ tumors following chemotherapy. Taken together, our work supports a therapeutic strategy for fighting the relapse of MNA⁺ neuroblastoma by targeting the immune microenvironment.

A retrospective evaluation of the presentation, prognostic factors and outcomes of neuroblastoma in Ugandan children

Neuroblastoma (NB) is the most common extracranial solid tumor of childhood. The complete burden and outcomes in Uganda are unknown. The study was a multicenter retrospective chart review of children aged between 0 to 15 years diagnosed with NB from 2010 to 2020. Demographic, clinical and tumor-related characteristics were extracted for analysis. Kaplan-Meier survival curves and Cox regression models were used to determine the one-year overall survival (OS) and identify prognostic factors. Seventy-five patients were evaluated, with a median age at diagnosis of 48 months (IQR 26-108 months). Fever (74.7%), weight loss (74.7%), high blood pressure (70.3%) and abdominal swelling/mass (65.3%) were the most common features at diagnosis. Suprarenal tumors (52%) and stage 4 disease (70.7%) were also common. The one-year OS was 60.0% (95%CI 56.8%; 64.3%) with a median survival time of 12.6 months (95% CI: 8.1; 20.8). The one-year OS for non-metastatic and metastatic disease was 67.3% and 42.6% (p = 0.11) respectively. Leukocytosis (p < 0.001) at diagnosis was of prognostic significance while clinical remission after induction chemotherapy (p < 0.001) provided survival advantages. Children who received maintenance chemotherapy had a longer median survival time of 38.5 months (range 10.8-69.5). Age (p = 0.001), lung metastasis (p < 0.001), and leukocytosis (p < 0.001) remained significant on multivariate analysis. In this Ugandan study, leukocytosis was a clinical predictor of prognosis, metastatic disease had management challenges and maintenance chemotherapy prolonged the survival time but not OS.

Anti-GRP-R monoclonal antibody antitumor therapy against neuroblastoma

Standard treatment for patients with high-risk neuroblastoma remains multimodal therapy including chemoradiation, surgical resection, and autologous stem cell rescue. Immunotherapy has demonstrated success in treating many types of cancers; however, its use in pediatric solid tumors has been limited by low tumor mutation burdens. Gastrin-releasing peptide receptor (GRP-R) is overexpressed in numerous malignancies, including poorly-differentiated neuroblastoma. Monoclonal antibodies (mAbs) to GRP-R have yet to be developed but could serve as a potential novel immunotherapy. This preclinical study aims to evaluate the efficacy of a novel GRP-R mAb immunotherapy against neuroblastoma. We established four candidate anti-GRP-R mAbs by screening a single-chain variable fragment (scFv) library. GRP-R mAb-1 demonstrated the highest efficacy with the lowest EC50 at 4.607 ng/ml against GRP-R expressing neuroblastoma cells, blocked the GRP-ligand activation of GRP-R and its downstream PI3K/AKT signaling. This resulted in functional inhibition of cell proliferation and anchorage-independent growth, indicating that mAb-1 has an antagonist inhibitory role on GRP-R. To examine the antibody-dependent cellular cytotoxicity (ADCC) of GRP-R mAb-1 on neuroblastoma, we co-cultured neuroblastoma cells with natural killer (NK) cells versus GRP-R mAb-1 treatment alone. GRP-R mAb-1 mediated ADCC effects on neuroblastoma cells and induced release of IFNγ by NK cells under co-culture conditions in vitro. The cytotoxic effects of mAb-1 were confirmed with the secretion of cytotoxic granzyme B from NK cells and the reduction of mitotic tumor cells in vivo using a murine tumor xenograft model. In summary, GRP-R mAb-1 demonstrated efficacious anti-tumor effects on neuroblastoma cells in preclinical models. Importantly, GRP-R mAb-1 may be an efficacious, novel immunotherapy in the treatment of high-risk neuroblastoma patients.

BCI, an inhibitor of the DUSP1 and DUSP6 dual specificity phosphatases, enhances P2X7 receptor expression in neuroblastoma cells

P2X7 receptor (P2RX7) is expressed strongly by most human cancers, including neuroblastoma, where high levels of P2RX7 are correlated with a poor prognosis for patients. Tonic activation of P2X7 receptor favors cell metabolism and angiogenesis, thereby promoting cancer cell proliferation, immunosuppression, and metastasis. Although understanding the mechanisms that control P2X7 receptor levels in neuroblastoma cells could be biologically and clinically relevant, the intracellular signaling pathways involved in this regulation remain poorly understood. Here we show that (E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI), an allosteric inhibitor of dual specificity phosphatases (DUSP) 1 and 6, enhances the expression of P2X7 receptor in N2a neuroblastoma cells. We found that exposure to BCI induces the phosphorylation of mitogen-activated protein kinases p38 and JNK, while it prevents the phosphorylation of ERK1/2. BCI enhanced dual specificity phosphatase 1 expression, whereas it induced a decrease in the dual specificity phosphatase 6 transcripts, suggesting that BCI-dependent inhibition of dual specificity phosphatase 1 may be responsible for the increase in p38 and JNK phosphorylation. The weaker ERK phosphorylation induced by BCI was reversed by p38 inhibition, indicating that this MAPK is involved in the regulatory loop that dampens ERK activity. The PP2A phosphatase appears to be implicated in the p38-dependent dephosphorylation of ERK1/2. In addition, the PTEN phosphatase inhibition also prevented ERK1/2 dephosphorylation, probably through p38 downregulation. By contrast, inhibition of the p53 nuclear factor decreased ERK phosphorylation, probably enhancing the activity of p38. Finally, the inhibition of either p38 or Sp1-dependent transcription halved the increase in P2X7 receptor expression induced by BCI. Moreover, the combined inhibition of both p38 and Sp1 completely prevented the effect exerted by BCI. Together, our results indicate that dual specificity phosphatase 1 acts as a novel negative regulator of P2X7 receptor expression in neuroblastoma cells due to the downregulation of the p38 pathway.

SOX4 Mediates ATRA-Induced Differentiation in Neuroblastoma Cells

Neuroblastoma (NB), which is considered to be caused by the differentiation failure of neural crest cells, is the most common extracranial malignant solid tumor in children. The degree of tumor differentiation in patients with NB is closely correlated with the survival rate. To explore the potential targets that mediate NB cell differentiation, we analyzed four microarray datasets from GEO, and the overlapping down- or upregulated DEGs were displayed using Venn diagrams. SOX4 was one of the overlapping upregulated DEGs and was confirmed by RT-qPCR and Western blot in ATRA-treated NGP, SY5Y, and BE2 cells. To clarify whether SOX4 was the target gene regulating NB cell differentiation, the correlation between the expression of SOX4 and the survival of clinical patients was analyzed via the R2 database, SOX4 overexpression plasmids and siRNAs were generated to change the expression of SOX4, RT-qPCR and Western blot were performed to detect SOX4 expression, cell confluence or cell survival was detected by IncuCyte Zoom or CCK8 assay, immunocytochemistry staining was performed to detect cells' neurites, and a cell cycle analysis was implemented using Flow cytometry after PI staining. The results showed that the survival probabilities were positively correlated with SOX4 expression, in which overexpressing SOX4 inhibited NB cell proliferation, elongated the cells' neurite, and blocked the cell cycle in G1 phase, and that knockdown of the expression of SOX4 partially reversed the ATRA-induced inhibition of NB cell proliferation, the elongation of the cells' neurites, and the blocking of the cell cycle in the G1 phase. These indicate that SOX4 may be a target to induce NB cell differentiation.

ERK Inhibitor Ulixertinib Inhibits High-Risk Neuroblastoma Growth In Vitro and In Vivo

Neuroblastoma (NB) is a pediatric tumor of the peripheral nervous system. Approximately 80% of relapsed NB show RAS-MAPK pathway mutations that activate ERK, resulting in the promotion of cell proliferation and drug resistance. Ulixertinib, a first-in-class ERK-specific inhibitor, has shown promising antitumor activity in phase 1 clinical trials for advanced solid tumors. Here, we show that ulixertinib significantly and dose-dependently inhibits cell proliferation and colony formation in different NB cell lines, including PDX cells. Transcriptomic analysis revealed that ulixertinib extensively inhibits different oncogenic and neuronal developmental pathways, including EGFR, VEGF, WNT, MAPK, NGF, and NTRK1. The proteomic analysis further revealed that ulixertinib inhibits the cell cycle and promotes apoptosis in NB cells. Additionally, ulixertinib treatment significantly sensitized NB cells to the conventional chemotherapeutic agent doxorubicin. Furthermore, ulixertinib potently inhibited NB tumor growth and prolonged the overall survival of the treated mice in two different NB mice models. Our preclinical study demonstrates that ulixertinib, either as a single agent or in combination with current therapies, is a novel and practical therapeutic approach for NB.

Advances in liquid biopsy in neuroblastoma

Even with intensive treatment of high-risk neuroblastoma (NB) patients, half of high-risk NB patients still relapse. New therapies targeting the biological characteristics of NB have important clinical value for the personalized treatment of NB. However, the current biological markers for NB are mainly analyzed by tissue biopsy. In recent years, circulating biomarkers of NB based on liquid biopsy have attracted more and more attention. This review summarizes the analytes and methods for liquid biopsy of NB. We focus on the application of liquid biopsy in the diagnosis, prognosis assessment, and monitoring of NB. Finally, we discuss the prospects and challenges of liquid biopsy in NB.

Exosomes in Neuroblastoma Biology, Diagnosis, and Treatment

Neuroblastoma is an extracranial solid tumour of the developing sympathetic nervous system accounting for circa 15% of deaths due to cancer in paediatric patients. The clinical course of this cancer may be variable, ranging from aggressive progression to regression, while the amplification of MYCN in this cancer is linked to poor patient prognosis. Extracellular vesicles are a double membrane encapsulating various cellular components including proteins and nucleic acids and comprise exosomes, apoptotic bodies, and microvesicles. The former can act as mediators between cancer, stromal and immune cells and thereby influence the tumour microenvironment by the delivery of their molecular cargo. In this study, the contribution of extracellular vesicles including exosomes to the biology, prognosis, diagnosis and treatment of neuroblastoma was catalogued, summarised and discussed. The understanding of these processes may facilitate the in-depth dissection of the complexity of neuroblastoma biology, mechanisms of regression or progression, and potential diagnostic and treatment options for this paediatric cancer which will ultimately improve the quality of life of neuroblastoma patients.

Chromosome instability in neuroblastoma: A pathway to aggressive disease

For over 100-years, genomic instability has been investigated as a central player in the pathogenesis of human cancer. Conceptually, genomic instability includes an array of alterations from small deletions/insertions to whole chromosome alterations, referred to as chromosome instability. Chromosome instability has a paradoxical impact in cancer. In most instances, the introduction of chromosome instability has a negative impact on cellular fitness whereas in cancer it is usually associated with a worse prognosis. One exception is the case of neuroblastoma, the most common solid tumor outside of the brain in children. Neuroblastoma tumors have two distinct patterns of genome instability: whole-chromosome aneuploidy, which is associated with a better prognosis, or segmental chromosomal alterations, which is a potent negative prognostic factor. Through a computational screen, we found that low levels of the de- ubiquitinating enzyme USP24 have a highly significant negative impact on survival in neuroblastoma. At the molecular level, USP24 loss leads to destabilization of the microtubule assembly factor CRMP2 - producing mitotic errors and leading to chromosome missegregation and whole-chromosome aneuploidy. This apparent paradox may be reconciled through a model in which whole chromosome aneuploidy leads to the subsequent development of segmental chromosome alterations. Here we review the mechanisms behind chromosome instability and the evidence for the progressive development of segmental alterations from existing numerical aneuploidy in support of a multi-step model of neuroblastoma progression.

Pharmacophore-Model-Based Virtual-Screening Approaches Identified Novel Natural Molecular Candidates for Treating Human Neuroblastoma

The mortality of cancer patients with neuroblastoma is increasing due to the limited availability of specific treatment options. Few drug candidates for combating neuroblastoma have been developed, and identifying novel therapeutic candidates against the disease is an urgent issue. It has been found that muc-N protein is amplified in one-third of human neuroblastomas and expressed as an attractive drug target against the disease. The myc-N protein interferes with the bromodomain and extraterminal (BET) family proteins. Pharmacologically inhibition of the protein potently depletes MYCN in neuroblastoma cells. BET inhibitors target MYCN transcription and show therapeutic efficacy against neuroblastoma. Therefore, the study aimed to identify potential inhibitors against the BET family protein, specifically Brd4 (brodamine-containing protein 4), to hinder the activity of neuroblastoma cells. To identify effective molecular candidates against the disease, a structure-based pharmacophore model was created for the binding site of the Brd4 protein. The pharmacophore model generated from the protein Brd4 was validated to screen potential natural active compounds. The compounds identified through the pharmacophore-model-based virtual-screening process were further screened through molecular docking, ADME (absorption, distribution, metabolism, and excretion), toxicity, and molecular dynamics (MD) simulation approach. The pharmacophore-model-based screening process initially identified 136 compounds, further evaluated based on molecular docking, ADME analysis, and toxicity approaches, identifying four compounds with good binding affinity and lower side effects. The stability of the selected compounds was also confirmed by dynamic simulation and molecular mechanics with generalized Born and surface area solvation (MM-GBSA) methods. Finally, the study identified four natural lead compounds, ZINC2509501, ZINC2566088, ZINC1615112, and ZINC4104882, that will potentially inhibit the activity of the desired protein and help to fight against neuroblastoma and related diseases. However, further evaluations through in vitro and in vivo assays are suggested to identify their efficacy against the desired protein and disease.

Minimal residual disease detected by droplet digital PCR in peripheral blood stem cell grafts has a prognostic impact on high-risk neuroblastoma patients

More than half of high-risk neuroblastoma (NB) patients have experienced relapse due to the activation of chemoresistant minimal residual disease (MRD) even though they are treated by high-dose chemotherapy with autologous peripheral blood stem cell (PBSC) transplantation. Although MRD in high-risk NB patients can be evaluated by quantitative PCR with several sets of neuroblastoma-associated mRNAs (NB-mRNAs), the prognostic significance of MRD in PBSC grafts (PBSC-MRD) is unclear. In the present study, we collected 20 PBSC grafts from 20 high-risk NB patients and evaluated PBSC-MRD detected by droplet digital PCR (ddPCR) with 7NB-mRNAs (CRMP1, DBH, DDC, GAP43, ISL1, PHOX2B, and TH mRNA). PBSC-MRD in 11 relapsed patients was significantly higher than that in 9 non-relapsed patients. Patients with a higher PBSC-MRD had a lower 3-year event-free survival (P = 0.0148). The present study suggests that PBSC-MRD detected by ddPCR with 7NB-mRNAs has a prognostic impact on high-risk NB patients.