Neuroblastoma

LINC00839 Promotes Neuroblastoma Progression by Sponging miR-454-3p to Up-Regulate NEUROD1

Neuroblastoma (NB) is the most common extracranial solid malignancy in children. Increasing long non-coding RNAs (lncRNAs) are reported to be associated with NB tumorigenesis and aggressiveness. Here, we attempted to investigate the biological functions of LINC00839 in NB progression as well as its possible pathogenic mechanisms. Public microarray datasets were applied to unearth the abnormally expressed lncRNAs in NB. RT-qPCR analysis was used to measure the expression of LINC00839, miR-454-3p, and neuronal differentiation 1 (NEUROD1) mRNA. The protein level was determined by a western blot assay. CCK-8, plate clone formation, EdU, wound-healing scratch, and transwell assays were employed to evaluate cell proliferation, migration, and invasion. Xenografts were developed in nude mice to determine the effects of LINC00839 on NB tumor growth. Dual-luciferase reporter and RNA immunoprecipitation (RIP) experiments were performed to identify the interaction between miR-454-3p and LINC00839 or NEUROD1. According to GSE datasets (GSE16237 and GSE16476), LINC00839 was found as a potential driver of NB progression. LINC00839 expression was higher in NB tumor tissues and cells. Also, LINC00839 expression was positively correlated with MYCN amplification, advanced INSS stages, and worse prognosis. Silencing of LINC00839 suppressed cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro. Mechanistically, LINC00839 could act as a sponge of miR-454-3p to facilitate the expression of its target NEUROD1. Moreover, miR-454-3p was demonstrated to exert an anti-cancer activity in NB. More importantly, the tumor-suppressive properties mediated by LINC00839 knockdown were significantly counteracted by the inhibition of miR-454-3p or overexpression of NEUROD1. Our study demonstrates that LINC00839 exerts an oncogenic role in NB through sponging miR-454-3p to up-regulate NEUROD1 expression, deepening our comprehension of lncRNA involved in NB and providing access to the possibility of LINC00839 as a therapeutic target for NB.

Cell Adhesion Molecules in Neuroblastoma: Complex Roles, Therapeutic Potential

Neuroblastoma, a biologically heterogeneous tumor derived from neural crest cells, accounts for approximately 15% of childhood deaths from cancer. Recently, scientific literature has explored the role of cell adhesion molecules (CAMs) in cancer metastasis through cell detachment, migration, and invasion. Through a review of the current literature, it is evident that expression of different CAMs on neuroblastoma tumors is associated with favorable or unfavorable clinical prognosis. In patients diagnosed with neuroblastoma, treatment strategies include chemotherapy, surgery, radiotherapy, stem cell transplant, and more recently, immunotherapy and other targeted therapies. Long term survival remains poor despite multimodality treatment, especially for children with high-risk neuroblastoma, making it more necessary to explore innovative targeted therapies. CAMs have immense potential as therapeutic targets, but there is a need for growth and scientific exploration before CAM therapies become clinically useful.

Iron Transporters and Ferroptosis in Malignant Brain Tumors

Malignant brain tumors represent approximately 1.5% of all malignant tumors. The survival rate among patients is relatively low and the mortality rate of pediatric brain tumors ranks first among all childhood malignant tumors. At present malignant brain tumors remain incurable. Although some tumors can be treated with surgery and chemotherapy, new treatment strategies are urgent owing to the poor clinical prognosis. Iron is an essential trace element in many biological processes of the human body. Iron transporters play a crucial role in iron absorption and transport. Ferroptosis, an iron-dependent form of nonapoptotic cell death, is characterized by the accumulation of lipid peroxidation products and lethal reactive oxygen species (ROS) derived from iron metabolism. Recently, compelling evidence has shown that inducing ferroptosis of tumor cells is a potential therapeutic strategy. In this review, we will briefly describe the significant regulatory factors of ferroptosis, iron, its absorption and transport under physiological conditions, especially the function of iron transporters. Then we will summarize the relevant mechanisms of ferroptosis and its role in malignant brain tumors, wherein the role of transporters is not to be ignored. Finally, we will introduce the current research progress in the treatment of malignant brain tumors by inducing ferroptosis in order to explain the current biological principles of potential treatment targets and treatment strategies for malignant brain tumors.

Upregulation of p75NTR by Histone Deacetylase Inhibitors Sensitizes Human Neuroblastoma Cells to Targeted Immunotoxin-Induced Apoptosis

Histone deacetylase (HDAC) inhibitors are novel chemotherapy agents with potential utility in the treatment of neuroblastoma, the most frequent solid tumor of childhood. Previous studies have shown that the exposure of human neuroblastoma cells to some HDAC inhibitors enhanced the expression of the common neurotrophin receptor p75NTR. In the present study we investigated whether the upregulation of p75NTR could be exploited to render neuroblastoma cells susceptible to the cytotoxic action of an anti-p75NTR antibody conjugated to the toxin saporin-S6 (p75IgG-Sap). We found that two well-characterized HDAC inhibitors, valproic acid (VPA) and entinostat, were able to induce a strong expression of p75NTR in different human neuroblastoma cell lines but not in other cells, with entinostat, displaying a greater efficacy than VPA. Cell pretreatment with entinostat enhanced p75NTR internalization and intracellular saporin-S6 delivery following p75IgG-Sap exposure. The addition of p75IgG-Sap had no effect on vehicle-pretreated cells but potentiated the apoptotic cell death that was induced by entinostat. In three-dimensional neuroblastoma cell cultures, the subsequent treatment with p75IgG-Sap enhanced the inhibition of spheroid growth and the impairment of cell viability that was produced by entinostat. In athymic mice bearing neuroblastoma xenografts, chronic treatment with entinostat increased the expression of p75NTR in tumors but not in liver, kidney, heart, and cerebellum. The administration of p75IgG-Sap induced apoptosis only in tumors of mice that were pretreated with entinostat. These findings define a novel experimental strategy to selectively eliminate neuroblastoma cells based on the sequential treatment with entinostat and a toxin-conjugated anti-p75NTR antibody.

BRD4 inhibitor GNE987 exerts anti-cancer effects by targeting super-enhancers in neuroblastoma

Background

Neuroblastoma (NB) is a common extracranial malignancy with high mortality in children. Recently, super-enhancers (SEs) have been reported to play a critical role in the tumorigenesis and development of NB via regulating a wide range of oncogenes Thus, the synthesis and identification of chemical inhibitors specifically targeting SEs are of great urgency for the clinical therapy of NB. This study aimed to characterize the activity of the SEs inhibitor GNE987, which targets BRD4, in NB.

Results

In this study, we found that nanomolar concentrations of GNE987 markedly diminished NB cell proliferation and survival via degrading BRD4. Meanwhile, GNE987 significantly induced NB cell apoptosis and cell cycle arrest. Consistent with in vitro results, GNE987 administration (0.25 mg/kg) markedly decreased the tumor size in the xenograft model, with less toxicity, and induced similar BRD4 protein degradation to that observed in vitro. Mechanically, GNE987 led to significant downregulation of hallmark genes associated with MYC and the global disruption of the SEs landscape in NB cells. Moreover, a novel candidate oncogenic transcript, FAM163A, was identified through analysis of the RNA-seq and ChIP-seq data. FAM163A is abnormally transcribed by SEs, playing an important role in NB occurrence and development.

Conclusion

GNE987 destroyed the abnormal transcriptional regulation of oncogenes in NB by downregulating BRD4, which could be a potential therapeutic candidate for NB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00769-8.

Multiple Immunofluorescence Imaging Analysis Reveals Differential Expression of Disialogangliosides GD3 and GD2 in Neuroblastomas

BACKGROUND

Peripheral neuroblastic tumors (pNTs) are the most common childhood extracranial solid tumors. There are several therapeutic strategies targeting disialoganglioside GD2. Disialoganglioside GD3 has become a potential target. However, the mechanism by which pNTs express GD3 and GD2 remains unclear. We investigated the combined expression status of GD3 and GD2 in pNTs and delineated their clinicopathological values.

METHODS

GD3 and GD2 expression was examined in pNT tissue samples (n = 35) using immunohistochemistry and multiple immunofluorescence imaging.

RESULTS

GD3 and GD2 expression was positive in 32/35 and 25/35 samples, respectively. Combinatorial analysis of GD3 and GD2 expression in neuroblastoma showed that both were heterogeneously expressed from cell to cell. There were higher numbers of GD3-positive and GD2-negative cells in the low-risk group than in the intermediate-risk (P = 0.014) and high-risk (P = 0.009) groups. Cases with high proportions of GD3-positive and GD2-negative cells were associated with the International Neuroblastoma Staging System stage (P = 0.004), Children's Oncology Group risk group (P = 0.001), and outcome (P = 0.019) and tended to have a higher overall survival rate.

CONCLUSION

We demonstrated that neuroblastomas from low-risk patients included more GD3-positive and GD2-negative cells than those from high-risk patients. Clarifying the heterogeneity of neuroblastoma aids in better understanding the biological characteristics and clinical behavior.

The efficacy and safety of Iodine-131-metaiodobenzylguanidine therapy in patients with neuroblastoma: a meta-analysis

Objective

Neuroblastoma is a common extracranial solid tumor of childhood. Recently, multiple treatments have been practiced including Iodine-131-metaiodobenzylguanidine radiation (¹³¹I-MIBG) therapy. However, the outcomes of efficacy and safety vary greatly among different studies. The aim of this meta-analysis is to evaluate the efficacy and safety of ¹³¹I-MIBG in the treatment of neuroblastoma and to provide evidence and hints for clinical decision-making.

Methods

Medline, EMBASE database and the Cochrane Library were searched for relevant studies. Eligible studies utilizing ¹³¹I-MIBG in the treatment of neuroblastoma were included. The pooled outcomes (response rates, adverse events rates, survival rates) were calculated using either a random-effects model or a fixed-effects model considering of the heterogeneity.

Results

A total of 26 clinical trials including 883 patients were analyzed. The pooled rates of objective response, stable disease, progressive disease, and minor response of ¹³¹I-MIBG monotherapy were 39%, 31%, 22% and 15%, respectively. The pooled objective response rate of ¹³¹I-MIBG in combination with other therapies was 28%. The pooled 1-year survival and 5-year survival rates were 64% and 32%. The pooled occurrence rates of thrombocytopenia and neutropenia in MIBG monotherapy studies were 53% and 58%. In the studies of ¹³¹I-MIBG combined with other therapies, the pooled occurrence rates of thrombocytopenia and neutropenia were 79% and 78%.

Conclusion

¹³¹I-MIBG treatment alone or in combination of other therapies is effective on clinical outcomes in the treatment of neuroblastoma, individualized ¹³¹I-MIBG is recommended on a clinical basis.

Different tumorigenicity and distinct metastasis and gene signature between orthotopic and subcutaneous neuroblastoma xenografted mice

Patient-derived (PDX) and cell-derived (CDX) xenograft models are widely used in preclinical studies of human neuroblastoma. In this study, we constructed orthotopic and subcutaneous neuroblastoma CDX models by injecting human neuroblastoma cells into the adrenal gland and the flanks of immunodeficient mice, respectively. The tumorigenesis, metastasis and response to chemotherapy for the two models were also compared. Our results indicated that orthotopic tumor mice showed significantly faster tumor growth than that of subcutaneous mice. Importantly, the expression of PHOX2B and GAB2 was dramatically increased in the tumors of orthotopic CDX mice. Furthermore, orthotopic CDX mice developed multiple organ metastasis resembling that of neuroblastoma patients, while metastasis occurred predominantly in lung in subcutaneous CDX mice. Moreover, the two CDX models showed comparable response to cyclophosphamide treatment. Our results suggest that orthotopic CDX mice are superior to subcutaneous CDX mice as a preclinical model to study human neuroblastoma.

Congenital hypogonadotropic hypogonadism complicated by neuroblastoma

A 3-mo-old male infant was referred to our hospital with micropenis. Since his serum LH, FSH, and testosterone levels were low (< 0.3 mIU/mL, 0.08 mIU/mL, and < 0.03 ng/mL, respectively), Kallmann syndrome/normosmic hypogonadotropic hypogonadism was suspected. In the process of searching for complications of Kallmann syndrome/normosmic hypogonadotropic hypogonadism, a right adrenal gland tumor was incidentally discovered. The patient was diagnosed with stage 1 neuroblastoma. A homozygous p.P147L (c.C440T) mutation in the KISS1R gene was detected as a cause of the congenital hypogonadotropic hypogonadism. KISS1-KISS1R signaling, which is essential for GnRH secretion, exhibits anti-metastatic and/or anti-tumoral roles in numerous cancers. High KISS1 expression levels reportedly predict better survival outcomes than low KISS1 expression levels in neuroblastoma. Therefore, decreased KISS1-KISS1R signaling may have played a role in the neuroblastoma in this patient.

Progress of oncolytic virotherapy for neuroblastoma

As a neuroendocrine tumor derived from the neural crest, neuroblastoma (NB) is the most common extracranial solid tumor in children. The prognosis in patients with low- and intermediate-risk NB is favorable while that in high-risk patients is often detrimental. However, the management of the considerably large proportion of high-risk patients remains challenging in clinical practice. Among various new approaches, oncolytic virus (OV) therapy offers great advantages in tumor treatment, especially for high-risk NB. Genetic modified OVs can target NB specifically without affecting normal tissue and avoid the widespread drug resistance issue in anticancer monotherapy. Meanwhile, its safety profile provides great potential in combination therapy with chemo-, radio-, and immunotherapy. The therapeutic efficacy of OV for NB is impressive from bench to bedside. The effectiveness and safety of OVs have been demonstrated and reported in studies on children with NB. Furthermore, clinical trials on some OVs (Celyvir, Pexa-Vec (JX-594) and Seneca Valley Virus (NTX-010)) have reported great results. This review summarizes the latest evidence in the therapeutic application of OVs in NB, including those generated in cell lines, animal models and clinical trials.

YTHDC1 gene polymorphisms and neuroblastoma susceptibility in Chinese children

Neuroblastoma (NB) is the most common extracranial tumor in children. YTHDC1, a member of RNA methylation modification binding proteins, plays critical roles in tumor occurrence and metastasis. However, it is unclear whether YTHDC1 gene polymorphisms are related to NB susceptibility. Herein, we aimed to evaluate the association between YTHDC1 gene polymorphisms (rs2293596 T>C, rs2293595 T>C, rs3813832 T>C) and susceptibility of NB by logistic regression models. In this eight-center case-control study, 898 patients with NB and 1734 healthy controls were genotyped by TaqMan assay. The results showed that rs3813832 TC genotype could significantly reduce the susceptibility of NB compared with the TT genotype [adjusted odds ratio (AOR) = 0.81, 95% confidence interval (CI) = 0.68-0.96, P = 0.018]. Combined genotype analysis revealed that individuals with 3 protective genotypes had a prominently lower NB risk than those with 0-2 protective genotypes (AOR = 0.80, 95% CI = 0.68-0.94, P = 0.006). The stratified analysis also demonstrated the protective effect of rs3813832 TC/CC and 3 protective genotypes in certain subgroups. Further functional experiments revealed that YTHDC1 siRNA-554, targeting the area near the rs3813832 T>C polymorphism site, could observably inhibit the proliferation and migration of NB cells. In conclusion, our findings highlight the involvement of YTHDC1 gene and its genetic variants in the etiology of NB.

hsa_circ_0013401 Accelerates the Growth and Metastasis and Prevents Apoptosis and Autophagy of Neuroblastoma Cells by Sponging miR-195 to Release PAK2

Background

Increased levels of circRNAs have been identified in a variety of cancers. However, the specific functions and mechanisms of circRNAs in neuroblastoma (NB) have not been fully explored.

Methods

The levels of hsa_circ_0045997, hsa_circ_0080307, hsa_circ_0013401, hsa_circ_0077578, and microRNA-195 were confirmed by RT-qPCR in NB. Gain- and loss-of-function assays and rescue experiments were conducted to determine the influence of hsa_circ_0013401, miR-195, and P21-activated kinase 2 (PAK2) on the proliferation, apoptosis, autophagy, migration, and invasion of NB cells. Regulatory gene targets were validated by the luciferase assay. A xenograft mouse model was used to determine the in vivo effects of hsa_circ_0013401.

Results

hsa_circ_0013401 was highly expressed, miR-195 was lowly expressed, and there was a negative correlation between hsa_circ_0013401 and miR-195 in NB. The inhibitory effects of hsa_circ_0013401 knockdown suppressed the proliferation, migration, and invasion and induced the apoptosis and autophagy of NB cells by targeting miR-195 to downregulate PAK2 expression. Luciferase reporter assays showed that miR-195 was a direct target of hsa_circ_0013401, and PAK2 was the downstream target gene of miR-195. In vivo studies showed that hsa_circ_0013401 promotes tumor formation.

Conclusions

hsa_circ_0013401 induced NB progression through miR-195 to enhance PAK2. Therefore, we might highlight a novel regulatory axis (hsa_circ_0013401/miR-195/PAK2) in NB.

Synthetic Heterocyclic Derivatives as Kinase Inhibitors Tested for the Treatment of Neuroblastoma

In the last few years, small molecules endowed with different heterocyclic scaffolds have been developed as kinase inhibitors. Some of them are being tested at preclinical or clinical levels for the potential treatment of neuroblastoma (NB). This disease is the most common extracranial solid tumor in childhood and is responsible for 10% to 15% of pediatric cancer deaths. Despite the availability of some treatments, including the use of very toxic cytotoxic chemotherapeutic agents, high-risk (HR)-NB patients still have a poor prognosis and a survival rate below 50%. For these reasons, new pharmacological options are urgently needed. This review focuses on synthetic heterocyclic compounds published in the last five years, which showed at least some activity on this severe disease and act as kinase inhibitors. The specific mechanism of action, selectivity, and biological activity of these drug candidates are described, when established. Moreover, the most remarkable clinical trials are reported. Importantly, kinase inhibitors approved for other diseases have shown to be active and endowed with lower toxicity compared to conventional cytotoxic agents. The data collected in this article can be particularly useful for the researchers working in this area.

FGFR2 loss sensitizes MYCN-amplified neuroblastoma CHP134 cells to CHK1 inhibitor-induced apoptosis

Checkpoint kinase 1 (CHK1) plays a key role in genome surveillance and integrity throughout the cell cycle. Selective inhibitors of CHK1 (CHK1i) are undergoing clinical evaluation for various human malignancies, including neuroblastoma. In this study, one CHK1i‐sensitive neuroblastoma cell line, CHP134, was investigated, which characteristically carries MYCN amplification and a chromosome deletion within the 10q region. Among several cancer‐related genes in the chromosome 10q region, mRNA expression of fibroblast growth factor receptor 2 (FGFR2) was altered in CHP134 cells and associated with an unfavorable prognosis of patients with neuroblastoma. Induced expression of FGFR2 in CHP134 cells reactivated downstream MEK/ERK signaling and resulted in cells resistant to CHK1i‐mediated cell growth inhibition. Consistently, the MEK1/2 inhibitor, trametinib, potentiated CHK1 inhibitor–mediated cell death in these cells. These results suggested that FGFR2 loss might be prone to highly effective CHK1i treatment. In conclusion, extreme cellular dependency of ERK activation may imply a possible application for the MEK1/2 inhibitor, either as a single inhibitor or in combination with CHK1i in MYCN‐amplified neuroblastomas.

Molecular Basis and Clinical Features of Neuroblastoma

Neuroblastoma, a neoplasm of the sympathetic nervous system, originates from neuroblastoma stem cells during embryogenesis. It exhibits unique clinical features including a tendency for spontaneous regression of tumors in infants and a high frequency of metastatic disease at diagnosis in patients aged over 18 months. Genetic risk factors and epigenetic dysregulation also play a significant role in the development of neuroblastoma. Over the past decade, our understanding of this disease has advanced considerably. This has included the identification of chromosomal copy number aberrations specific to neuroblastoma development, risk groups, and disease stage. However, high-risk neuroblastoma remains a therapeutic challenge for pediatric oncologists. New therapeutic approaches have been developed, either as alternatives to conventional chemotherapy or in combination, to overcome the dismal prognosis. Particularly promising strategies are targeted therapies that directly affect cancer cells or cancer stem cells while exhibiting minimal effect on healthy cells. This review summarizes our understanding of neuroblastoma biology and prognostic features and focuses on novel therapeutic strategies for this intractable disease.

Analysis of Asymmetric Cell Division Using Human Neuroblastoma Cell Lines as a Model System

Neuroblastoma is one of the most common childhood solid tumors and develops from neural stem cells that normally comprise the embryonic structure termed the neural crest. Human neuroblastoma cell lines have special properties as they exhibit cell growth and are induced to become mature neurons by drugs such as retinoid. Therefore, we examined asymmetric cell division (ACD) using human neuroblastoma cells as an ACD model, and confirmed that ACD in human cancer cells is evolutionally conserved. Furthermore, we demonstrated that MYCN is involved in cell division fate. We introduce the brief history of ACD study using neuroblastoma cell lines and discuss why human neuroblastoma cells are an ideal model system for clarifying the mechanism of ACD.

Neuroblastoma Cells Depend on CSB for Faithful Execution of Cytokinesis and Survival

Neuroblastoma, the most common extra-cranial solid tumor of early childhood, is one of the major therapeutic challenges in child oncology: it is highly heterogenic at a genetic, biological, and clinical level. The high-risk cases have one of the least favorable outcomes amongst pediatric tumors, and the mortality rate is still high, regardless of the use of intensive multimodality therapies. Here, we observed that neuroblastoma cells display an increased expression of Cockayne Syndrome group B (CSB), a pleiotropic protein involved in multiple functions such as DNA repair, transcription, mitochondrial homeostasis, and cell division, and were recently found to confer cell robustness when they are up-regulated. In this study, we demonstrated that RNAi-mediated suppression of CSB drastically impairs tumorigenicity of neuroblastoma cells by hampering their proliferative, clonogenic, and invasive capabilities. In particular, we observed that CSB ablation induces cytokinesis failure, leading to caspases 9 and 3 activation and, subsequently, to massive apoptotic cell death. Worthy of note, a new frontier in cancer treatment, already proved to be successful, is cytokinesis-failure-induced cell death. In this context, CSB ablation seems to be a new and promising anticancer strategy for neuroblastoma therapy.

Comparison of Next-Generation Sequencing and Fluorescence In Situ Hybridization for Detection of Segmental Chromosomal Aberrations in Neuroblastoma

The aim of this study was to compare next-generation sequencing (NGS) with the traditional fluorescence in situ hybridization (FISH) for detecting segmental chromosomal aberrations (SCAs) such as 1p deletion, 11q deletion and 17q gain, which are well-known predictive markers for adverse outcome in neuroblastoma. The tumor tissue obtained from 35 patients with neuroblastoma was tested by FISH and targeted NGS, which is specially designed to detect copy number alterations across the entire chromosomal region in addition to mutations in 353 cancer-related genes. All chromosomal copy number alterations were analyzed using the copy number variation plot derived from targeted NGS. FISH was performed to detect 1p deletion, 11q deletion and 17q gain. The copy numbers of 1p, 11q, and 17q obtained via NGS were correlated with those acquired via FISH. The SCAs determined by NGS were matched with those by FISH. Most 17q gain of mismatched cases detected by NGS alone showed a subsegmental gain of 17q. FISH revealed 11q deletion and 17q gain in a few tumor cells of two cases, which were not detected by NGS. NGS can be a sensitive complementary and alternative method to the conventional FISH for detecting SCAs.

The synergistic antitumor effect of combination therapy with a MEK inhibitor and YAP inhibitor on pERK-positive neuroblastoma

BACKGROUND

We previously reported the in vitro and in vivo antitumor effects of trametinib, a MEK inhibitor, on neuroblastoma with MAPK pathway mutations. As we observed eventual resistance to trametinib in our previous study, we evaluated the combination therapy of CA3, a YAP inhibitor, with trametinib, based on a recent report suggesting the potential involvement of YAP in the mechanism underlying the resistance to trametinib in neuroblastoma.

METHODS

SK-N-AS cells (a neuroblastoma cell line harboring RAS mutation) were treated with CA3 in vitro and subjected to a viability assay, immunocytochemistry and flow cytometry. Next, we analyzed the in vitro combination effect of CA3 and trametinib using the CompuSyn software program. Finally, we administered CA3, trametinib or both to SK-N-AS xenograft mice for 10 weeks to analyze the combination effect.

RESULTS

CA3 inhibited cell proliferation by both cell cycle arrest and apoptosis in vitro. Combination of CA3 and trametinib induced a significant synergistic effect in vitro (Combination Index <1). Regarding the in vivo experiment, combination therapy suppressed tumor growth, and 100% of mice in the combination therapy group survived, whereas the survival rates were 0% in the CA3 group and 33% in the trametinib group. However, despite this promising survival rate in the combination group, the tumors gradually grew after seven weeks with MAPK reactivation.

CONCLUSION

Our results indicated that CA3 and trametinib exerted synergistic antitumor effects on neuroblastoma in vitro and in vivo, and CA3 may be a viable option for concomitant drug therapy with trametinib, since it suppressed the resistance to trametinib. However, this combination effect was not sufficient to achieve complete remission. Therefore, we need to adjust the protocol to obtain a better outcome by determining the mechanism underlying regrowth in the future.

Neuroblastoma: A Case of Massive Hepatomegaly

Neuroblastoma is the most common embryonal tumor of childhood and has a variable presentation. Stage 4S neuroblastoma, described as a localized primary tumor in an infant with metastasis to skin, liver, or bone marrow, is an exception to the poor prognosis seen in widespread metastasis of neuroblastoma. Survival in infants with this stage of the disease is over 90%. Stage 4S with massive liver involvement, however, confers a poor prognosis. We need more research on the optimum treatment modality for patients with Stage 4S disease and massive hepatomegaly to improve patient outcomes.

Therapeutic Targeting of the Anaplastic Lymphoma Kinase (ALK) in Neuroblastoma-A Comprehensive Update

Neuroblastoma (NBL) is an embryonic malignancy of the sympathetic nervous system and mostly affects children under the age of five. NBL is highly heterogeneous and ranges from spontaneously regressing to highly aggressive disease. One of the risk factors for poor prognosis are aberrations in the receptor tyrosine kinase anaplastic lymphoma kinase (ALK), which is involved in the normal development and function of the nervous system. ALK mutations lead to constitutive activation of ALK and its downstream signalling pathways, thus driving tumorigenesis. A wide range of steric ALK inhibitors has been synthesized, and several of these inhibitors are already in clinical use. Major challenges are acquired drug resistance to steric inhibitors and pathway evasion strategies of cancer cells upon targeted therapy. This review will give a comprehensive overview on ALK inhibitors in clinical use in high-risk NBL and on the potential and limitations of novel inhibitors. Because combinatory treatment regimens are probably less likely to induce drug resistance, a special focus will be on the combination of ALK inhibitors with drugs that either target downstream signalling pathways or that affect the survival and proliferation of cancer cells in general.

Role of Notch pathway in effect of mono-2-ethylhexyl phthalate on the proliferation and cell cycle of SH-SY5Y cell

Neuroblastoma (NB) is an estrogen-dependent tumor. Mono-2-ethylhexyl phthalate (MEHP) has an estrogen-like effect. However, the effects of MEHP on the progression of NB are not well illustrated. This study was to clarify the effect of Notch pathway on proliferation and cell cycle of SH-SY5Y cell induced by MEHP. The viability of SH-SY5Y and BE2C cells were detected by CCK8; cell cycle and apoptosis were detected by flow cytometry; the protein expression levels of Notch pathway and cell cycle related proteins were detected by Western-blot. Results show that MEHP exposure can promote cell proliferation and altered the cell cycle. MEHP exposure can up-regulate the expression of C-MYC, Cyclin D1, Bcl-2 and affected the Notch pathway. In conclusion, MEHP exposure can promote NB cell proliferation and affect the cell cycle and apoptosis. Notch pathway plays a critical role in accelerating the cell cycle and inhibiting the apoptosis of SH-SY5Y cells caused by MEHP.

Analysis of SARS-CoV-2 infection associated cell entry proteins ACE2, CD147, PPIA, and PPIB in datasets from non SARS-CoV-2 infected neuroblastoma patients, as potential prognostic and infection biomarkers in neuroblastoma

SARS-CoV-2 viral contagion has given rise to a worldwide pandemic. Although most children experience minor symptoms from SARS-CoV-2 infection, some have severe complications including Multisystem Inflammatory Syndrome in Children. Neuroblastoma patients may be at higher risk of severe infection as treatment requires immunocompromising chemotherapy and SARS-CoV-2 has demonstrated tropism for nervous cells. To date, there is no sufficient epidemiological data on neuroblastoma patients with SARS-CoV-2. Therefore, we evaluated datasets of non-SARS-CoV-2 infected neuroblastoma patients to assess for key genes involved with SARS-CoV-2 infection as possible neuroblastoma prognostic and infection biomarkers. We hypothesized that ACE2, CD147, PPIA and PPIB, which are associated with viral-cell entry, are potential biomarkers for poor prognosis neuroblastoma and SARS-CoV-2 infection. We have analysed three publicly available neuroblastoma gene expression datasets to understand the specific molecular susceptibilities that high-risk neuroblastoma patients have to the virus. Gene Expression Omnibus (GEO) GSE49711 and GEO GSE62564 are the microarray and RNA-Seq data, respectively, from 498 neuroblastoma samples published as part of the Sequencing Quality Control initiative. TARGET, contains microarray data from 249 samples and is part of the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) initiative. ACE2, CD147, PPIA and PPIB were identified through their involvement in both SARS-CoV-2 infection and cancer pathogenesis. In-depth statistical analysis using Kaplan-Meier, differential gene expression, and Cox multivariate regression analysis, demonstrated that overexpression of ACE2, CD147, PPIA and PPIB is significantly associated with poor-prognosis neuroblastoma samples. These results were seen in the presence of amplified MYCN, unfavourable tumour histology and in patients older than 18 months of age. Previously, we have shown that high levels of the nerve growth factor receptor NTRK1 together with low levels of the phosphatase PTPN6 and TP53 are associated with increased relapse-free survival of neuroblastoma patients. Interestingly, low levels of expression of ACE2, CD147, PPIA and PPIB are associated with this NTRK1-PTPN6-TP53 module, suggesting that low expression levels of these genes are associated with good prognosis. These findings have implications for clinical care and therapeutic treatment. The upregulation of ACE2, CD147, PPIA and PPIB in poor-prognosis neuroblastoma samples suggests that these patients may be at higher risk of severe SARS-CoV-2 infection. Importantly, our findings reveal ACE2, CD147, PPIA and PPIB as potential biomarkers and therapeutic targets for neuroblastoma.

Enzymatic Spermine Metabolites Induce Apoptosis Associated with Increase of p53, caspase-3 and miR-34a in Both Neuroblastoma Cells, SJNKP and the N-Myc-Amplified Form IMR5

Neuroblastoma (NB) is a common malignant solid tumor in children and accounts for 15% of childhood cancer mortality. Amplification of the N-Myc oncogene is a well-established poor prognostic marker in NB patients and strongly correlates with higher tumor aggression and resistance to treatment. New therapies for patients with N-Myc-amplified NB need to be developed. After treating NB cells with BSAO/SPM, the detection of apoptosis was determined after annexin V-FITC labeling and DNA staining with propidium iodide. The mitochondrial membrane potential activity was checked, labeling cells with the probe JC-1 dye. We analyzed, by real-time RT-PCR, the transcript of genes involved in the apoptotic process, to determine possible down- or upregulation of mRNAs after the treatment on SJNKP and the N-Myc-amplified IMR5 cell lines with BSAO/SPM. The experiments were carried out considering the proapoptotic genes Tp53 and caspase-3. After treatment with BSAO/SPM, both cell lines displayed increased mRNA levels for all these proapoptotic genes. Western blotting analysis with PARP and caspase-3 antibody support that BSAO/SPM treatment induces high levels of apoptosis in cells. The major conclusion is that BSAO/SPM treatment leads to antiproliferative and cytotoxic activity of both NB cell lines, associated with activation of apoptosis.

Functional and Clinical Characteristics of Cell Adhesion Molecule CADM1 in Cancer

The cell adhesion molecule CADM1, which participates in cell adhesion and signal transduction, has a regulatory effect on the development of tumors. CADM1 is often involved in malignant tumors of multiple organ systems, such as the respiratory and digestive systems. Upregulated CADM1 promotes tumor cell apoptosis and inhibits malignant proliferation. Along with cell cycle-related proteins, it participates in regulating signaling pathways, such as EMT, STAT3, and AKT, and plays an important role in inhibiting invasion and migration. Considering clinical characteristics, low CADM1 expression is associated with aggressive tumors and poor prognosis. In addition, some long non-coding RNAs (lncRNAs) or miRNAs directly or indirectly act on CADM1 to regulate tumor growth and motility. Interestingly, CADM1 function differs in adult T-cell leukemia/lymphoma (ATLL), and NF-κB is thought to be involved in this process. Taken together, CADM1 could be a potential biomarker for early diagnosis and a target for cancer treatment in future clinical practices.

How Do Telomere Abnormalities Regulate the Biology of Neuroblastoma?

Telomere maintenance plays important roles in genome stability and cell proliferation. Tumor cells acquire replicative immortality by activating a telomere-maintenance mechanism (TMM), either telomerase, a reverse transcriptase, or the alternative lengthening of telomeres (ALT) mechanism. Recent advances in the genetic and molecular characterization of TMM revealed that telomerase activation and ALT define distinct neuroblastoma (NB) subgroups with adverse outcomes, and represent promising therapeutic targets in high-risk neuroblastoma (HRNB), an aggressive childhood solid tumor that accounts for 15% of all pediatric-cancer deaths. Patients with HRNB frequently present with widely metastatic disease, with tumors harboring recurrent genetic aberrations (MYCN amplification, TERT rearrangements, and ATRX mutations), which are mutually exclusive and capable of promoting TMM. This review provides recent insights into our understanding of TMM in NB tumors, and highlights emerging therapeutic strategies as potential treatments for telomerase- and ALT-positive tumors.

Investigation of patient factors associated with the number of transfusions required during chemotherapy for high-risk neuroblastoma

BACKGROUND

Blood transfusion is an important supportive care for high-risk neuroblastoma. When the number of transfusions increases, transfusion-associated adverse reactions may be more problematic. However, the factors determining the degree of myelosuppression and the number of transfusions during chemotherapy for high-risk neuroblastoma remain unclear.

MATERIALS AND METHODS

We investigated patient factors determining the number of required transfusions in 15 high-risk neuroblastoma patients who received five courses of chemotherapy. Clinical data, cytokine profile and colony-forming assay with bone marrow samples at diagnosis were analysed.

RESULTS

The required number of transfusions of both platelets and erythrocytes decreased once in the second course and then increased as the course progressed. The variability among cases increased as the chemotherapy course progressed. In cases of low peripheral blood platelet count and lower fibrinogen level at diagnosis, the number of platelet transfusions was higher during chemotherapy. In contrast, there was a negative correlation between the forming ability of granulocyte-macrophage or erythroid colonies and the number of erythrocyte transfusions in the latter period.

CONCLUSION

In the early stages of chemotherapy, bone marrow infiltration in neuroblastoma and/or coagulopathy complication may cause thrombocytopenia and requirement of platelet transfusion; conversely, in the later stages, the number of erythrocyte transfusions may be defined by the patient's inherent hematopoietic ability. These factors may be useful in predicting the required number of transfusions.

Molecular Genetics in Neuroblastoma Prognosis

In recent years, much research has been carried out to identify the biological and genetic characteristics of the neuroblastoma (NB) tumor in order to precisely define the prognostic subgroups for improving treatment stratification. This review will describe the major genetic features and the recent scientific advances, focusing on their impact on diagnosis, prognosis, and therapeutic solutions in NB clinical management.

A population-based analysis of clinical features and lymph node dissection in head and neck malignant neurogenic tumors

Background

The influence of lymph node dissection (LND) on survival in patients with head and neck neurogenic tumors remains unclear. We aimed to determine the effect of LND on the outcomes of patients with head and neck neurogenic tumors.

Methods

Data of patients with surgically treated head and neck neurogenic tumors were identified from the Surveillance, Epidemiology, and End Results (SEER) database (1975–2016) to investigate the relationship between LND and clinical outcomes by survival analysis. Subgroup analysis was performed in IVa and IVb group.

Results

In total, 662 head and neck neurogenic tumor patients (median age: 49.0 [0–91.0] years) met the inclusion criteria, of whom 13.1% were in the IVa group and 86.9% were in the IVb group. The median follow-up time was 76.0 months (range: 6.0–336.0 months), and the 5-year and 10-year overall survival was 82.4% (95% CI, 0.79–0.85) and 69.0% (95% CI, 0.64–0.73). Cox regression analysis revealed older age (P < .001), advanced stage (P = .037), African American race (P = .002), diagnosis before 2004 (P < .001), and chemotherapy administration (P < .001) to be independent negative predictors of overall survival. Kaplan-Meier analysis demonstrated that LND was not a predictor of clinical nodal negativity (cN0) in either IVa or IVb patients.

Conclusions

In head and neck neurogenic patients, LND may not impact the outcome of cN0 in either IVa or IVb group. These data can be recommended in guiding surgical plan and future studies.

Acceleration or Brakes: Which Is Rational for Cell Cycle-Targeting Neuroblastoma Therapy?

Unrestrained proliferation is a common feature of malignant neoplasms. Targeting the cell cycle is a therapeutic strategy to prevent unlimited cell division. Recently developed rationales for these selective inhibitors can be subdivided into two categories with antithetical functionality. One applies a “brake” to the cell cycle to halt cell proliferation, such as with inhibitors of cell cycle kinases. The other “accelerates” the cell cycle to initiate replication/mitotic catastrophe, such as with inhibitors of cell cycle checkpoint kinases. The fate of cell cycle progression or arrest is tightly regulated by the presence of tolerable or excessive DNA damage, respectively. This suggests that there is compatibility between inhibitors of DNA repair kinases, such as PARP inhibitors, and inhibitors of cell cycle checkpoint kinases. In the present review, we explore alterations to the cell cycle that are concomitant with altered DNA damage repair machinery in unfavorable neuroblastomas, with respect to their unique genomic and molecular features. We highlight the vulnerabilities of these alterations that are attributable to the features of each. Based on the assessment, we offer possible therapeutic approaches for personalized medicine, which are seemingly antithetical, but both are promising strategies for targeting the altered cell cycle in unfavorable neuroblastomas.

Overexpression of Endogenous Retroviruses and Malignancy Markers in Neuroblastoma Cell Lines by Medium-Induced Microenvironmental Changes

Neuroblastoma (NB) is the commonest solid tumor outside the central nervous system in infancy and childhood with a unique biological heterogeneity. In patients with advanced, metastasizing neuroblastoma, treatment failure and poor prognosis is often marked by resistance to chemo- or immunotherapy. Thus, identification of robust biomarkers seems essential for understanding tumor progression and developing effective therapy. Here, we have studied the expression of human endogenous retroviruses (HERV) as potential targets in NB cell lines during stem-cell medium-induced microenvironmental change. Quantitative PCR revealed that relative expression of the HERV-K family and HERV-W1 ENV were increased in all three NB cell lines after incubation in stem-cell medium. Virus transcriptome analyses revealed the transcriptional activation of three endogenous retrovirus elements: HERV-R ENV (ERV3-1), HERV-E1 and HERV-Fc2 ENV (ERVFC1-1). Known malignancy markers in NB, e.g. proto-oncogenic MYC or MYCN were expressed highly heterogeneously in the three investigated NB cell lines with up-regulation of MYC and MYCN upon medium-induced microenvironmental change. In addition, SiMa cells exclusively showed a phenotype switching from loosely-adherent monolayers to low proliferating grape-like cellular aggregates, which was accompanied by an enhanced CD133 expression. Interestingly, the overexpression of HERV was associated with a significant elevation of immune checkpoint molecule CD200 in both quantitative PCR and RNA-seq analysis suggesting tumor escape mechanism in NB cell lines after incubation in serum-free stem cell medium.

123I metaiodobenzylguanidine (MIBG) uptake predicts early relapse of neuroblastoma using semi-quantitative SPECT/CT analysis

OBJECTIVE

123I metaiodobenzylguanidine (MIBG) scintigraphy is a useful tool for the diagnosis of neuroblastoma (NB). MIBG uptake is correlated with norepinephrine transporter expression; hence, it is expected that high-MIBG tumors would be more highly differentiated and have a better prognosis than those with lower expression. We have introduced a method of assessing MIBG accumulation semi-quantitatively using SPECT/CT fusion images. The purpose of this study was to evaluate the relationship of 123I MIBG uptake measured by semi-quantitative values of SPECT/CT and early relapse of NB.

METHODS

We studied the cases of 11 patients (5 males and 6 females, age 5-65 months, median age 20 months) with histopathologically proven NB between April 2010 and March 2015. The early-relapse group was defined as patients who had relapsed within 3 years after the first 123I MIBG SPECT/CT exam. Other patients were classified as the delay-relapse group. Uptake of MIBG was evaluated using the count ratio of tumor and muscles. T/Mmax and T/Mmean were defined as follows: T/Mmax = max count of tumor/max count of muscle, T/Mmean = mean count of tumor/mean count of muscle.

RESULTS

The average T/Mmean values of the early-relapse group and delay-relapse group were 2.65 ± 0.58 and 7.66 ± 2.68, respectively. The T/Mmean values of the early-relapse group were significantly lower than those of delay-relapse group (p < 0.05). The average T/Mmax of the early-relapse group and delay-relapse group were 8.86 ± 3.22 and 16.20 ± 1.97, respectively. There was no significant difference in T/Mmax values between the two groups.

CONCLUSIONS

Low 123I MIBG uptake using semi-quantitative SPECT/CT analysis was correlated with early relapse of NB.

Differentiating Neuroblastoma: A Systematic Review of the Retinoic Acid, Its Derivatives, and Synergistic Interactions

A neuroblastoma (NB) is a solid paediatric tumour arising from undifferentiated neuronal cells. Despite the recent advances in disease management and treatment, it remains one of the leading causes of childhood cancer deaths, thereby necessitating the development of new therapeutic agents and regimens. Retinoic acid (RA), a vitamin A derivative, is a promising agent that can induce differentiation in NB cells. Its isoform, 13-cis RA or isotretinoin, is used in NB therapy; however, its effectiveness is limited to treating a minimal residual disease as maintenance therapy. As such, research focuses on RA derivatives that might increase the anti-NB action or explores the potential synergy between RA and other classes of drugs, such as cellular processes mediators, epigenetic modifiers, and immune modulators. This review summarises the in vitro, in vivo, and clinical data of RA, its derivatives, and synergising compounds, thereby establishing the most promising RA derivatives and combinations of RA for further investigation.

Prognostic Signature of Immune Genes and Immune-Related LncRNAs in Neuroblastoma: A Study Based on GEO and TARGET Datasets

Background

The prognostic value of immune-related genes and lncRNAs in neuroblastoma has not been elucidated, especially in subgroups with different outcomes. This study aimed to explore immune-related prognostic signatures.

Materials and Methods

Immune-related prognostic genes and lncRNAs were identified by univariate Cox regression analysis in the training set. The top 20 C-index genes and 17 immune-related lncRNAs were included in prognostic model construction, and random forest and the Least Absolute Shrinkage and Selection Operator (LASSO) regression algorithms were employed to select features. The risk score model was constructed and assessed using the Kaplan-Meier plot and the receiver operating characteristic curve. Functional enrichment analysis of the immune-related lncRNAs was conducted using the STRING database.

Results

In GSE49710, five immune genes (CDK4, PIK3R1, THRA, MAP2K2, and ULBP2) were included in the risk score five genes (RS5_G) signature, and eleven immune-related lncRNAs (LINC00260, FAM13A1OS, AGPAT4-IT1, DUBR, MIAT, TSC22D1-AS1, DANCR, MIR137HG, ERC2-IT1, LINC01184, LINC00667) were brought into risk score LncRNAs (RS_Lnc) signature. Patients were divided into high/low-risk score groups by the median. Overall survival and event/progression-free survival time were shortened in patients with high scores, both in training and validation cohorts. The same results were found in subgroups. In grouping ability assessment, the area under the curves (AUCs) in distinguishing different groups ranged from 0.737 to 0.94, better in discriminating MYCN status and high risk in training cohort (higher than 0.9). Multivariate Cox analysis demonstrated that RS5_G and RS_Lnc were the independent risk factors for overall and event/progression-free survival (all p-values <0.001). Correlation analysis showed that RS5_G and RS_Lnc were negatively associated with aDC, CD8+ T cells, but positively correlated with Th2 cells. Functional enrichment analyzes demonstrated that immune-related lncRNAs are mainly enriched in cancer-related pathways and immune-related pathways.

Conclusion

We identified the immune-related prognostic signature RS5_G and RS_Lnc. The predicting and grouping ability is close to being even better than those reported in other studies, especially in subgroups. This study provided prognostic signatures that may help clinicians to choose optimal treatment strategies and showed a new insight for NB treatment. These results need further biological experiments and clinical validation.

Phosphorylation of Specificity Protein 3 Is Critical for Activation of β4-Galactosyltransferase 3 Gene Promoter in SH-SY5Y Human Neuroblastoma Cell Line

Elevated expression of β4-galactosyltransferase (β4GalT) 3 is correlated with poor clinical outcome of neuroblastoma patients. Our recent study has revealed that the transcription of the β4GalT3 gene is activated by Specificity protein (Sp) 3 in SH-SY5Y human neuroblastoma cell line. Here we report the biological significance of the Sp3 phosphorylation in the transcriptional activation of the β4GalT3 gene. The treatment of SH-SY5Y cells with 10% fetal bovine serum (FBS) increased the mitogen-activated protein kinase (MAPK) signaling and the promoter activity of the β4GalT3 gene. Meanwhile, the treatment with U0126, an inhibitor for MAPK kinase, decreased the MAPK signaling and the promoter activity. These findings indicate that the transcriptional activation of the β4GalT3 gene is mediated by the MAPK signaling. In SH-SY5Y cells cultured in the medium containing 10% FBS, the serine (Ser) residues in Sp3 were phosphorylated. Human Sp3 contains four Ser residues, Ser73, Ser563, Ser566, and Ser646, as the putative phosphorylation sites. Sp3 mutant with the mutation of Ser73 did not decrease the promoter activation of the β4GalT3 gene, indicating that Ser73 is uninvolved in the promoter activation of the β4GalT3 gene by Sp3. In contrast, Sp3 mutants with the mutations of Ser563, Ser566, and Ser646 significantly reduced the promoter activation by Sp3. The results suggest that the phosphorylation of these Ser residues is implicated in the promoter activation by Sp3. This study demonstrates that the phosphorylation of Sp3 plays important roles in the transcriptional activation of the β4GalT3 gene in human neuroblastoma.

YTHDF2 Gene rs3738067 A>G Polymorphism Decreases Neuroblastoma Risk in Chinese Children: Evidence From an Eight-Center Case-Control Study

Neuroblastoma is a primary malignancy mainly occurring in children. We have reported that polymorphisms of several N6-methyladenosine (m6A) RNA modification-related genes contributed to neuroblastoma risk in previous studies. YTHDF2, a "reader" of RNA m6A modification, is involved in cancer progression. Here, we estimated the association between a YTHDF2 gene rs3738067 A>G polymorphism and neuroblastoma susceptibility in 898 neuroblastoma patients and 1,734 healthy individuals from China. We found that the rs3738067 A>G could decrease neuroblastoma risk [AG vs. AA: adjusted odds ratio (OR) = 0.76, 95% confidence interval (CI) = 0.64-0.90, P = 0.002; AG/GG vs. AA: adjusted OR = 0.81, 95% CI = 0.69-0.95, P = 0.011). Besides, the rs3738067 AG/GG genotype was related to reduced neuroblastoma risk in the following subgroups: children aged 18 months and under, boys, patients with tumors originating from retroperitoneal, patients at clinical stage IV, and cases at clinical stages III plus IV. Importantly, false-positive report probability analysis proved our significant results worthy of close attention of. The expression quantitative trait locus analysis results revealed that the rs3738067 was associated with the expression of YTHDF2.

Metastatic neuroblastoma mimicking an infantile hemangioma

Neuroblastoma is the most common solid tumor malignancy in the first year of life. We present a rare case of a 5-month-old girl with an infraorbital tumor that simulated an infantile hemangioma clinically but was ultimately diagnosed as metastatic neuroblastoma.

MicroRNAs at the Crossroad of the Dichotomic Pathway Cell Death vs. Stemness in Neural Somatic and Cancer Stem Cells: Implications and Therapeutic Strategies

Stemness and apoptosis may highlight the dichotomy between regeneration and demise in the complex pathway proceeding from ontogenesis to the end of life. In the last few years, the concept has emerged that the same microRNAs (miRNAs) can be concurrently implicated in both apoptosis-related mechanisms and cell differentiation. Whether the differentiation process gives rise to the architecture of brain areas, any long-lasting perturbation of miRNA expression can be related to the occurrence of neurodevelopmental/neuropathological conditions. Moreover, as a consequence of neural stem cell (NSC) transformation to cancer stem cells (CSCs), the fine modulation of distinct miRNAs becomes necessary. This event implies controlling the expression of pro/anti-apoptotic target genes, which is crucial for the management of neural/neural crest-derived CSCs in brain tumors, neuroblastoma, and melanoma. From a translational point of view, the current progress on the emerging miRNA-based neuropathology therapeutic applications and antitumor strategies will be disclosed and their advantages and shortcomings discussed.

MicroRNA-145 overexpression inhibits neuroblastoma tumorigenesis in vitro and in vivo

Neuroblastoma (NB) is responsible for 15% of all childhood cancer deaths. Despite advances in treatment and disease management, the overall 5-year survival rates remain poor in high-risk disease (25-40%). It is well known that miR-145 functions as a tumor suppressor in several types of cancer. However, the impact of miR-145 on NB is still ambiguous. Our aim was to investigate the potential tumor suppressive role and mechanisms of miR-145 in high-risk neuroblastoma. Expression levels of miR-145 in tissues and cells were determined using RT-qPCR. The effect of miR-145 on cell viability was evaluated using MTT assays, apoptosis levels were determined using TUNEL staining, and the MTDH protein expression was determined using western blot and RT-PCR. Luciferase reporter plasmids were constructed to confirm direct targeting for MTDH. The results showed that miR-145 expression was significantly lower in high-risk MYCN amplified (MNA) tumors and low miR-145 expression was associated with worse EFS and OS in our cohort. Over-expression of miR-145 reduced cell viability and increased apoptosis in SH-SY-5Y cells. We identified MTDH as a direct target for miR-145 in SH-SY-5Y cells. Targeting MTDH has the similar results as miR-145 overexpression. Our findings suggest that low miR-145 expression was associated with poor prognosis in patients with NB, and the overexpression of miR-145 inhibited NB cells growth by down-regulating MTDH, thus providing a potential target for the development of microRNA-based approach for NB therapy.

SNHG16 knockdown inhibits tumorigenicity of neuroblastoma in children via miR-15b-5p/PRPS1 axis

Neuroblastoma is an important problem in children. Long noncoding RNAs (lncRNAs) exhibit important roles in tumorigenicity of neuroblastoma. However, the role and mechanism of lncRNA small nucleolar RNA host gene 16 (SNHG16) in neuroblastoma tumorigenicity remain poorly understood. Forty-six neuroblastoma samples and 28 normal tissues were harvested. The levels of SNHG16, microRNA-15b-5p (miR-15b-5p), and phosphoribosyl pyrophosphate synthetase 1 (PRPS1) were detected via quantitative reverse transcription PCR or western blot. Cell proliferation as well as cycle distribution were measured via 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide or flow cytometry. Cell metastasis was investigated via epithelial-mesenchymal transition or transwell assay. The target relationship of miR-15b-5p and SNHG16 or PRPS1 was explored via starBase and dual-luciferase reporter assay. The role of SNHG16 in neuroblastoma in vivo was analyzed using a xenograft model. We found SNHG16 and PRPS1 levels were increased in neuroblastoma tissues and cells. SNHG16 knockdown inhibited cell proliferation, increased the cell cycle distribution at G0/G1 phase, and decreased the cells at S phase. SNHG16 overexpression caused an opposite effect. SNHG16 silence suppressed neuroblastoma cell metastasis. PRPS1 knockdown constrained cell proliferation and metastasis and regulated cell cycle distribution. miR-15b-5p was sponged by SNHG16 and directly targeted PRPS1. miR-15b-5p knockdown or PRPS1 overexpression mitigated the influence of SNHG16 silence on cell cycle, proliferation, and metastasis. SNHG16 knockdown reduced xenograft tumor growth. In conclusion, SNHG16 downregulation suppressed neuroblastoma tumorigenicity by regulating cell cycle, proliferation, and metastasis via miR-15b-5p/PRPS1 axis.

The Role of MYCN in Symmetric vs. Asymmetric Cell Division of Human Neuroblastoma Cells

Asymmetric cell division (ACD) is an important physiological event in the development of various organisms and maintenance of tissue homeostasis. ACD produces two different cells in a single cell division: a stem/progenitor cell and differentiated cell. Although the balance between self-renewal and differentiation is precisely controlled, disruptions to ACD and/or enhancements in the self-renewal division (symmetric cell division: SCD) of stem cells resulted in the formation of tumors in Drosophila neuroblasts. ACD is now regarded as one of the characteristics of human cancer stem cells, and is a driving force for cancer cell heterogeneity. We recently reported that MYCN controls the balance between SCD and ACD in human neuroblastoma cells. In this mini-review, we discuss the mechanisms underlying MYCN-mediated cell division fate.

Antiproliferative effect of mifepristone (RU486) on human neuroblastoma cells (SK-N-SH): in vitro and in vivo studies

RU486 (mifepristone), a glucocorticoid and progesterone receptor antagonist, has been reported to exert antiproliferative effects on tumor cells. Experiments were performed to analyze the effects of RU486 on the proliferation of the human neuroblastoma, both in vitro and in vivo, using the human neuroblastoma SK-N-SH cell line. The exposure in vitro of SK-N-SH cells to RU486 revealed a dose-dependent inhibition of ³H-thymidine incorporation due to a rapid but persistent inhibition of MAPKinase activity and ERK phosphorylation. A significant decrease of SK-N-SH cell number was evident after 3, 6, and 9 days of treatment (up to 40% inhibition), without evident cell death. The inhibitory effect exerted by RU486 was not reversed by the treatment of the cells with dexamethasone or progesterone. Moreover, RU486 induced a shift in SK-N-SH cell phenotypes, with an almost complete disappearance of the neuronal-like and a prevalence of the epithelial-like cell subtypes. Finally, the treatment with RU486 of nude mice carrying a SK-N-SH cell xenograft induced a strong inhibition (up to 80%) of tumor growth. These results indicated a clear effect of RU486 on the growth of SK-N-SH neuroblastoma cells that does not seem to be mediated through the classical steroid receptors. RU486 acted mainly on the more aggressive component of the SK-N-SH cell line and its effect in vivo was achieved at a concentration already used to inhibit oocyte implantation.

Targeting the p53-MDM2 pathway for neuroblastoma therapy: Rays of hope

Despite being the subject of extensive research and clinical trials, neuroblastoma remains a major therapeutic challenge in pediatric oncology. The p53 protein is a central safeguard that protects cells against genome instability and malignant transformation. Mutated TP53 (the gene encoding p53) is implicated in many human cancers, but the majority of neuroblastomas have wild type p53 with intact transcriptional function. In fact, the TP53 mutation rate does not exceed 1-2% in neuroblastomas. However, overexpression of the murine double minute 2 (MDM2) gene in neuroblastoma is relatively common, and leads to inhibition of p53. It is also associated with other non-canonical p53-independent functions, including drug resistance and increased translation of MYCN and VEGF mRNA. The p53-MDM2 pathway in neuroblastoma is also modulated at several different molecular levels, including via interactions with other proteins (MYCN, p14^ARF). In addition, the overexpression of MDM2 in tumors is linked to a poorer prognosis for cancer patients. Thus, restoring p53 function by inhibiting its interaction with MDM2 is a potential therapeutic strategy for neuroblastoma. A number of p53-MDM2 antagonists have been designed and studied for this purpose. This review summarizes the current understanding of p53 biology and the p53-dependent and -independent oncogenic functions of MDM2 in neuroblastoma, and also the regulation of the p53-MDM2 axis in neuroblastoma. This review also highlights the use of MDM2 as a molecular target for the disease, and describes the MDM2 inhibitors currently being investigated in preclinical and clinical studies. We also briefly explain the various strategies that have been used and future directions to take in the development of effective MDM2 inhibitors for neuroblastoma.