Search

Disseminating disease is a predictive and prognostic indicator of poor outcome in children with neuroblastoma. Its accurate and sensitive assessment can facilitate optimal treatment decisions. The International Neuroblastoma Risk Group (INRG) Task Force has defined standardised methods for the determination of minimal disease (MD) by immunocytology (IC) and quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) using disialoganglioside G(D2) and tyrosine hydroxylase mRNA respectively. The INRG standard operating procedures (SOPs) define methods for collecting, processing and evaluating bone marrow (BM), peripheral blood (PB) and peripheral blood stem cell harvest by IC and QRT-PCR. Sampling PB and BM is recommended at diagnosis, before and after myeloablative therapy and at the end of treatment. Peripheral blood stem cell products should be analysed at the time of harvest. Performing MD detection according to INRG SOPs will enable laboratories throughout the world to compare their results and thus facilitate quality-controlled multi-centre prospective trials to assess the clinical significance of MD and minimal residual disease in heterogeneous patient groups.

Background: Neuroblastoma is a childhood cancer with considerable morbidity and mortality. Tumor-derived biomarkers may improve risk stratification. Methods: We screened 915 samples of neuroblastoma for loss of heterozygosity (LOH) at chromosome bands 1p36 and 11q23. Additional analyses identified a subgroup of cases of 11q23 LOH with unbalanced 11q LOH (unb11q LOH; defined as loss of 11q with retention of 11p). The associations of LOH with relapse and survival were determined. Results: LOH at 1p36 was identified in 209 of 898 tumors (23 percent) and LOH at 11q23 in 307 of 913 (34 percent). Unb11q LOH was found in 151 of 307 tumors with 11q23 LOH (17 percent of the total cohort). There was a strong association of 1p36 LOH, 11q23 LOH, and unb11q LOH with most high-risk disease features (P<0.001). LOH at 1p36 was associated with amplification of the MYCN oncogene (P<0.001), but 11q23 LOH and unb11q LOH were not (P<0.001 and P=0.002, respectively). Cases with unb11q LOH were associated with three-year event-free and overall survival rates (+/-SE) of 50+/-5 percent and 66+/-5 percent, respectively, as compared with 74+/-2 percent and 83+/-2 percent among cases without unb11q LOH (P<0.001 for both comparisons). In a multivariate model, unb11q LOH was independently associated with decreased event-free survival (P=0.009) in the entire cohort, and both 1p36 LOH and unb11q LOH were independently associated with decreased progression-free survival in the subgroup of patients with features of low-risk and intermediate-risk disease (P=0.002 and P=0.02, respectively). Conclusions: Unb11q LOH and 1p36 LOH are independently associated with a worse outcome in patients with neuroblastoma. [ABSTRACT FROM AUTHOR]

Background: Minimal disease quantification may predict event-free survival (EFS) and overall survival (OS)., Methods: We evaluated mRNA expression of five neuroblastoma-associated genes (NB5 assay) in bone marrows (BM) of patients with newly diagnosed high-risk neuroblastoma who received consistent immunotherapy. mRNA expression of CHGA, DCX, DDC, PHOX2B, and TH genes in BM of 479 patients enrolled on the immunotherapy arm of Children's Oncology Group trials ANBL0032 and ANBL0931 was evaluated using real-time polymerase chain reaction (PCR)-based TaqMan low-density array. Results from end-consolidation and end-therapy were analyzed for association with five-year EFS/OS and patient and tumor characteristics. Tests of statistical significance were two-sided., Results: NB5 assay detected neuroblastoma-related mRNA in 222 of 286 (77.6%) of BMs obtained at end-consolidation and 188 of 304 (61.8%) at end-therapy. Any mRNA level detected in end-therapy BM correlated with significantly worse EFS (57% [49.6%-63.7%] vs 73.0% [63.5%-80.4%]; P = 0.005), but not OS. Analysis limited to patients in complete response at end-therapy still found a significant difference in EFS with detectable versus not detectable NB5 assay results (58.9% [49.5%-67.1%] vs 76.6% [66.1%-84.2%]; P = 0.01). End-consolidation results did not correlate with EFS or OS. Multivariable analysis determined end-therapy NB5 assay BM results (P = 0.02), age at diagnosis (P = 0.002), and preconsolidation response (P = 0.02) were significantly associated with EFS independent of other clinical and biological parameters evaluated, including end-therapy response., Conclusions: If further validated in additional patient cohorts, the NB5 assay's ability to independently predict EFS from end-therapy could improve patient stratification for novel maintenance therapy trials after current end-therapy to improve outcome., (© 2022 Wiley Periodicals LLC.)

Background: Immunotherapy with anti-disialoganglioside dinutuximab has improved survival for children with high-risk neuroblastoma (NB) when given after induction chemotherapy and surgery. However, disease recurrence and resistance persist. Dinutuximab efficacy has not been evaluated when initiated before primary tumor removal. Using a surgical mouse model of human NB, we examined if initiating dinutuximab plus ex vivo-activated natural killer (aNK) cells before resection of the primary tumor improves survival., Methods: In vitro, human NB cells (SMS-KCNR-Fluc, CHLA-255-Fluc) were treated with dinutuximab and/or aNK cells and cytotoxicity was measured. In vivo, NB cells (SMS-KCNR-Fluc, CHLA-255-Fluc, or COG-N-415x PDX) were injected into the kidney of NOD-scid gamma mice. Mice received eight intravenous infusions of aNK cells plus dinutuximab beginning either 12 days before or 2 days after resection of primary tumors. Tumors in control mice were treated by resection alone or with immunotherapy alone. Disease was quantified by bioluminescent imaging and survival was monitored. aNK cell infiltration into primary tumors was quantified by flow cytometry and immunohistochemistry at varying timepoints., Results: In vitro, aNK cells and dinutuximab were more cytotoxic than either treatment alone. In vivo, treatment with aNK cells plus dinutuximab prior to resection of the primary tumor was most effective in limiting metastatic disease and prolonging survival. aNK cell infiltration into xenograft tumors was observed after 1 day and peaked at 5 days following injection., Conclusion: Dinutuximab plus aNK cell immunotherapy initiated before resection of primary tumors decreases disease burden and prolongs survival in an experimental mouse model of NB. These findings support the clinical investigation of this treatment strategy during induction therapy in patients with high-risk NB., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Neuroblastoma is a malignancy of the developing sympathetic nervous system that accounts for 12% of childhood cancer deaths. Like many childhood cancers, neuroblastoma shows a relative paucity of somatic single-nucleotide variants (SNVs) and small insertions and deletions (indels) compared to adult cancers. Here, we assessed the contribution of somatic structural variation (SV) in neuroblastoma using a combination of whole-genome sequencing (WGS) of tumor-normal pairs ( n = 135) and single-nucleotide polymorphism (SNP) genotyping of primary tumors ( n = 914). Our study design allowed for orthogonal validation and replication across platforms. SV frequency, type, and localization varied significantly among high-risk tumors. MYCN nonamplified high-risk tumors harbored an increased SV burden overall, including a significant excess of tandem duplication events across the genome. Genes disrupted by SV breakpoints were enriched in neuronal lineages and associated with phenotypes such as autism spectrum disorder (ASD). The postsynaptic adapter protein-coding gene, SHANK2 , located on Chromosome 11q13, was disrupted by SVs in 14% of MYCN nonamplified high-risk tumors based on WGS and 10% in the SNP array cohort. Expression of SHANK2 was low across human-derived neuroblastoma cell lines and high-risk neuroblastoma tumors. Forced expression of SHANK2 in neuroblastoma cells resulted in significant growth inhibition ( P = 2.6 × 10 -2 to 3.4 × 10 -5 ) and accelerated neuronal differentiation following treatment with all- trans retinoic acid ( P = 3.1 × 10 -13 to 2.4 × 10 -30 ). These data further define the complex landscape of somatic structural variation in neuroblastoma and suggest that events leading to deregulation of neurodevelopmental processes, such as inactivation of SHANK2 , are key mediators of tumorigenesis in this childhood cancer., (© 2020 Lopez et al.; Published by Cold Spring Harbor Laboratory Press.)

Purpose: We determined whether elimination of CD105 + cells in the tumor microenvironment (TME) with anti-CD105 antibodies enhanced anti-disialoganglioside (GD2) antibody dinutuximab therapy of neuroblastoma when combined with activated natural killer (aNK) cells., Experimental Design: The effect of MSCs and monocytes on antibody-dependent cellular cytotoxicity (ADCC) mediated by dinutuximab with aNK cells against neuroblastoma cells was determined in vitro . ADCC with anti-CD105 mAb TRC105 and aNK cells against MSCs, monocytes, and endothelial cells, which express CD105, was evaluated. Anti-neuroblastoma activity in immunodeficient NSG mice of dinutuximab with aNK cells without or with anti-CD105 mAbs was determined using neuroblastoma cell lines and a patient-derived xenograft., Results: ADCC mediated by dinutuximab with aNK cells against neuroblastoma cells in vitro was suppressed by addition of MSCs and monocytes, and dinutuximab with aNK cells was less effective against neuroblastomas formed with coinjected MSCs and monocytes in NSG mice than against those formed by tumor cells alone. Anti-CD105 antibody TRC105 with aNK cells mediated ADCC against MSCs, monocytes, and endothelial cells. Neuroblastomas formed in NSG mice by two neuroblastoma cell lines or a patient-derived xenograft coinjected with MSCs and monocytes were most effectively treated with dinutuximab and aNK cells when anti-human (TRC105) and anti-mouse (M1043) CD105 antibodies were added, which depleted human MSCs and murine endothelial cells and macrophages from the TME., Conclusions: Immunotherapy of neuroblastoma with anti-GD2 antibody dinutuximab and aNK cells is suppressed by CD105 + cells in the TME, but suppression is overcome by adding anti-CD105 antibodies to eliminate CD105 + cells., (©2019 American Association for Cancer Research.)

In neuroblastoma, the interplay between immune cells of the tumor microenvironment and cancer cells contributes to immune escape mechanisms and drug resistance. In this study, we show that natural killer (NK) cell-derived exosomes carrying the tumor suppressor microRNA (miR)-186 exhibit cytotoxicity against MYCN-amplified neuroblastoma cell lines. The cytotoxic potential of these exosomes was partly dependent upon expression of miR-186. miR-186 was downregulated in high-risk neuroblastoma patients, and its low expression represented a poor prognostic factor that directly correlated with NK activation markers (i.e., NKG2D and DNAM-1). Expression of MYCN, AURKA, TGFBR1, and TGFBR2 was directly inhibited by miR-186. Targeted delivery of miR-186 to MYCN-amplified neuroblastoma or NK cells resulted in inhibition of neuroblastoma tumorigenic potential and prevented the TGFβ1-dependent inhibition of NK cells. Altogether, these data support the investigation of a miR-186-containing nanoparticle formulation to prevent tumor growth and TGFβ1-dependent immune escape in high-risk neuroblastoma patients as well as the inclusion of ex vivo -derived NK exosomes as a potential therapeutic option alongside NK cell-based immunotherapy. Significance: These findings highlight the therapeutic potential of NK cell-derived exosomes containing the tumor suppressor miR-186 that inhibits growth, spreading, and TGFβ-dependent immune escape mechanisms in neuroblastoma., (©2018 American Association for Cancer Research.)

Extracellular vesicles (EVs) are secreted membrane vesicles, which play complex physiological and pathological functions in intercellular communication. Recently, we isolated natural killer (NK) cell-derived EVs (NK-EVs) from ex vivo expansion of NK cell cultures. The isolated NK-EVs contained cytotoxic proteins and several activated caspases, and they induced apoptosis in target cells. In this report, the protein levels of cytotoxic proteins from NK-EV isolates were analysed by ELISA. The mean values of perforin (PFN, 550 ng/mL), granzyme A (GzmA, 185 ng/mL), granzyme B (GzmB, 23.4 ng/mL), granulysin (GNLY, 56 ng/mL), and FasL (2.5 ng/mL) were obtained from >60 isolations using dot plots. The correlation between cytotoxicity and cytotoxic protein levels was examined by linear regression. PFN, GzmA, GzmB, GNLY all had a positive, moderate correlation with cytotoxicity, suggesting that there is not a single cytotoxic protein dominantly involved in killing and that all of these proteins may contribute to cytotoxicity. To further explore the possible killing mechanisms, cells were treated with NK-EVs, proteins extracted and lysates assessed by Western blotting. The levels of Gzm A substrates, SET and HMG2, were diminished in targeted cells, indicating that GzmA may induce a caspase-independent death pathway. Also, cytochrome C was released from mitochondria, a central hallmark of caspase-dependent death pathways. In addition, several ER-associated proteins were altered, suggesting that NK-EVs may induce ER stress resulting in cell death. Our results indicate that multiple killing mechanisms are activated by NK-derived EVs, including caspase-independent and -dependent cell death pathways, which can mediate cytotoxicity against cancer cells. Abbreviations : NK: natural killer cells; aNK: activated NK cells; EV: extracellular vesicles; ER: endoplasmic reticulum; ALL: acute lymphoblastic leukaemia; FBS: foetal bovine serum. GzmA: granzyme A; GzmB: granzyme B; GNLY: granulysin; PFN: perforin.

Purpose: Immunotherapy of neuroblastoma that remains after myeloablative chemotherapy with anti-GD2 antibody dinutuximab has increased the two-year event-free and overall survival of high-risk neuroblastoma patients; however, 40% of patients develop recurrent disease during or after this treatment. To determine the potential of such antibody-based immunotherapy earlier in treatment, a mouse model was developed in which surgical resection of the primary tumor was followed by therapy of residual disease with dinutuximab combined with ex vivo -activated human natural killer (aNK) cells., Experimental Design: The effect of combining dinutuximab with human aNK cells was determined in vitro with cellular cytotoxicity and Matrigel invasion assays. The in vivo efficacy of dinutuximab and aNK cells against neuroblastoma was assessed following resection of primary tumors formed by two cell lines or a patient-derived xenograft (PDX) in immunodeficient NOD-scid gamma mice., Results: In vitro , the combination of aNK cells and dinutuximab caused cytotoxicity and decreased invasiveness of three human neuroblastoma cell lines. Treatment of mice with dinutuximab combined with aNK cells after surgical resection of primary intrarenal tumors formed by two cell lines or a PDX decreased tumor cells in liver and bone marrow as evaluated by histopathology and bioluminescence imaging. Survival of mice after resection of these tumors was most significantly increased by treatment with dinutuximab combined with aNK cells compared with that of untreated mice., Conclusions: The combination of dinutuximab and adoptively transferred human aNK cells following surgical resection of primary neuroblastomas significantly improves survival of immunodeficient mice., (©2018 American Association for Cancer Research.)

Tumor-associated macrophages can promote growth of cancers. In neuroblastoma, tumor-associated macrophages have greater frequency in metastatic versus loco-regional tumors, and higher expression of genes associated with macrophages helps to predict poor prognosis in the 60% of high-risk patients who have MYCN-non-amplified disease. The contribution of cytotoxic T-lymphocytes to anti-neuroblastoma immune responses may be limited by low MHC class I expression and low exonic mutation frequency. Therefore, we modelled human neuroblastoma in T-cell deficient mice to examine whether depletion of monocytes/macrophages from the neuroblastoma microenvironment by blockade of CSF-1R can improve the response to chemotherapy. In vitro, CSF-1 was released by neuroblastoma cells, and topotecan increased this release. In vivo, neuroblastomas formed by subcutaneous co-injection of human neuroblastoma cells and human monocytes into immunodeficient NOD/SCID mice had fewer human CD14 + and CD163 + cells and mouse F4/80 + cells after CSF-1R blockade. In subcutaneous or intra-renal models in immunodeficient NSG or NOD/SCID mice, CSF-1R blockade alone did not affect tumor growth or mouse survival. However, when combined with cyclophosphamide plus topotecan, the CSF-1R inhibitor BLZ945, either without or with anti-human and anti-mouse CSF-1 mAbs, inhibited neuroblastoma growth and synergistically improved mouse survival. These findings indicate that depletion of tumor-associated macrophages from neuroblastomas can be associated with increased chemotherapeutic efficacy without requiring a contribution from T-lymphocytes, suggesting the possibility that combination of CSF-1R blockade with chemotherapy might be effective in patients who have limited anti-tumor T-cell responses., (© 2018 UICC.)

Single agent studies targeting the tumor microenvironment in central nervous system (CNS) tumors have largely been disappointing. Combination therapies targeting various pathways and cell types may be a more effective strategy. In this phase I study, we evaluated the combination of dasatinib, lenalidomide, and temozolomide in children with relapsed or refractory primary CNS tumors. Patients 1-21 years old with relapsed or refractory CNS tumors were eligible. Starting doses of dasatinib and lenalidomide were 65 mg/m 2 /dose twice daily and 55 mg/m 2 once daily, respectively, while temozolomide was constant at 75 mg/m 2 daily. The study followed a 3 + 3 phase I design, with a 4-week dose-limiting toxicity (DLT) evaluation period. Serial peripheral blood lymphocyte subsets were evaluated in consenting patients. Fifteen patients were enrolled and thirteen were DLT-evaluable. DLTs occurred in 5 patients, including somnolence and confusion (1 patient), hypokalemia (1 patient) and thrombocytopenia (3 patients). The maximum tolerated dose for the combination was dasatinib 65 mg/m 2 twice daily, lenalidomide 40 mg/m 2 daily, and temozolomide 75 mg/m 2 daily, for 21 days followed by 7 days rest in repeating 28-day cycles. Transient increases in natural killer effector cells and cytotoxic T-cells were seen after 1 week of treatment. One out of six response-evaluable patients showed a partial response. The combination was feasible and relatively well tolerated in this heavily pre-treated population. The most common toxicities were hematologic. Preliminary evidence of clinical benefit was seen.

High-risk neuroblastomas show a paucity of recurrent somatic mutations at diagnosis. As a result, the molecular basis for this aggressive phenotype remains elusive. Recent progress in regulatory network analysis helped us elucidate disease-driving mechanisms downstream of genomic alterations, including recurrent chromosomal alterations. Our analysis identified three molecular subtypes of high-risk neuroblastomas, consistent with chromosomal alterations, and identified subtype-specific master regulator proteins that were conserved across independent cohorts. A 10-protein transcriptional module-centered around a TEAD4-MYCN positive feedback loop-emerged as the regulatory driver of the high-risk subtype associated with MYCN amplification. Silencing of either gene collapsed MYCN -amplified ( MYCN Amp ) neuroblastoma transcriptional hallmarks and abrogated viability in vitro and in vivo Consistently, TEAD4 emerged as a robust prognostic marker of poor survival, with activity independent of the canonical Hippo pathway transcriptional coactivators YAP and TAZ. These results suggest novel therapeutic strategies for the large subset of MYCN-deregulated neuroblastomas. Significance: Despite progress in understanding of neuroblastoma genetics, little progress has been made toward personalized treatment. Here, we present a framework to determine the downstream effectors of the genetic alterations sustaining neuroblastoma subtypes, which can be easily extended to other tumor types. We show the critical effect of disrupting a 10-protein module centered around a YAP/TAZ-independent TEAD4-MYCN positive feedback loop in MYCN Amp neuroblastomas, nominating TEAD4 as a novel candidate for therapeutic intervention. Cancer Discov; 8(5); 582-99. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 517 ., (©2018 American Association for Cancer Research.)

Neuroblastomas with a high mitosis-karyorrhexis index (High-MKI) are often associated with MYCN amplification, MYCN protein overexpression and adverse clinical outcome. However, the prognostic effect of MYC-family protein expression on these neuroblastomas is less understood, especially when MYCN is not amplified. To address this, MYCN and MYC protein expression in High-MKI cases (120 MYCN amplified and 121 non- MYCN amplified) was examined by immunohistochemistry. The majority (101) of MYCN -amplified High-MKI tumors were MYCN(+), leaving one MYC(+), 2 both(+), and 16 both(-)/(+/-), whereas non- MYCN -amplified cases appeared heterogeneous, including 7 MYCN(+), 36 MYC(+), 3 both(+), and 75 both(-)/(+/-) tumors. These MYC-family proteins(+), or MYC-family driven tumors, were most likely to have prominent nucleolar (PN) formation (indicative of augmented rRNA synthesis). High-MKI neuroblastoma patients showed a poor survival irrespective of MYCN amplification. However, patients with MYC-family driven High-MKI neuroblastomas had significantly lower survival than those with non-MYC-family driven tumors. MYCN(+), MYC-family protein(+), PN(+), and clinical stage independently predicted poor survival. Specific inhibition of hyperactive rRNA synthesis and protein translation was shown to be an effective way to suppress MYC/MYCN protein expression and neuroblastoma growth. Together, MYC-family protein overexpression and PN formation should be included in new neuroblastoma risk stratification and considered for potential therapeutic targets., Competing Interests: CONFLICTS OF INTEREST The authors have no conflicts of interest to disclose in relation to manuscript.

Extracellular vesicles (EVs) deliver bioactive macromolecules (i.e. proteins, lipids and nucleic acids) for intercellular communication in multicellular organisms. EVs are secreted by all cell types including immune cells. Immune cell-derived EVs modulate diverse aspects of the immune system to either enhance or suppress immune activities. The extensive effects of immune cell-derived EVs have become the focus of great interest for various nano-biomedical applications, ranging from the medical use of nanoplatform-based diagnostic agents to the development of therapeutic interventions as well as vaccine applications, and thus may be ideal for 'immune-theranostic'. Here, we review the latest advances concerning the biological roles of immune cell-derived EVs in innate and acquired immunity. The intercellular communication amongst immune cells through their EVs is highlighted, showing that all immune cell-derived EVs have their unique function(s) in immunity through intricate interaction(s). Natural-killer (NK) cell-derived EVs, for example, contain potent cytotoxic proteins and induce apoptosis to targeted cancer cells. On the other hand, cancer cell-derived EVs bearing NK ligands may evade immune surveillance and responses. Finally, we discuss possible medical uses for the immune cell-derived EVs as a tool for immune-theranostic: as diagnostic biomarkers, for use in therapeutic interventions and for vaccination., Competing Interests: No potential conflict of interest was reported by the authors.

Cancer-associated fibroblasts (CAF) have been suggested to originate from mesenchymal stromal cells (MSC), but their relationship with MSCs is not clear. Here, we have isolated from primary human neuroblastoma tumors a population of αFAP- and FSP-1-expressing CAFs that share phenotypic and functional characteristics with bone marrow-derived MSCs (BM-MSC). Analysis of human neuroblastoma tumors also confirmed the presence of αFAP- and FSP-1-positive cells in the tumor stroma, and their presence correlated with that of M2 tumor-associated macrophages. These cells (designated CAF-MSCs) enhanced in vitro neuroblastoma cell proliferation, survival, and resistance to chemotherapy and stimulated neuroblastoma tumor engraftment and growth in immunodeficient mice, indicating an effect independent of the immune system. The protumorigenic activity of MSCs in vitro and in xenografted mice was dependent on the coactivation of JAK2/STAT3 and MEK/ERK1/2 in neuroblastoma cells. In a mouse model of orthotopically implanted neuroblastoma cells, inhibition of JAK2/STAT3 and MEK/ERK/1/2 by ruxolitinib and trametinib potentiated tumor response to etoposide and increased overall survival. These data point to a new type of protumorigenic CAF in the tumor microenvironment of neuroblastoma and to STAT3 and ERK1/2 as mediators of their activity. Cancer Res; 77(18); 5142-57. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Purpose: We determined whether quantifying neuroblastoma-associated mRNAs (NB-mRNAs) in bone marrow and blood improves assessment of disease and prediction of disease progression in patients with relapsed/refractory neuroblastoma. Experimental Design: mRNA for CHGA, DCX, DDC, PHOX2B, and TH was quantified in bone marrow and blood from 101 patients concurrently with clinical disease evaluations. Correlation between NB-mRNA (delta cycle threshold, Δ C t , for the geometric mean of genes from the TaqMan Low Density Array NB5 assay) and morphologically defined tumor cell percentage in bone marrow, 123 I-meta-iodobenzylguanidine (MIBG) Curie score, and CT/MRI-defined tumor longest diameter was determined. Time-dependent covariate Cox regression was used to analyze the relationship between Δ C t and progression-free survival (PFS). Results: NB-mRNA was detectable in 83% of bone marrow (185/223) and 63% (89/142) of blood specimens, and their Δ C t values were correlated (Spearman r = 0.67, P < 0.0001), although bone marrow C t was 7.9 ± 0.5 C t stronger than blood C t When bone marrow morphology, MIBG, or CT/MRI were positive, NB-mRNA was detected in 99% (99/100), 88% (100/113), and 81% (82/101) of bone marrow samples. When all three were negative, NB-mRNA was detected in 55% (11/20) of bone marrow samples. Bone marrow NB-mRNA correlated with bone marrow morphology or MIBG positivity ( P < 0.0001 and P = 0.007). Bone marrow and blood Δ C t values correlated with PFS ( P < 0.001; P = 0.001) even when bone marrow was morphologically negative ( P = 0.001; P = 0.014). Multivariate analysis showed that bone marrow and blood Δ C t values were associated with PFS independently of clinical disease and MYCN gene status ( P < 0.001; P = 0.055). Conclusions: This five-gene NB5 assay for NB-mRNA improves definition of disease status and correlates independently with PFS in relapsed/refractory neuroblastoma. Clin Cancer Res; 23(18); 5374-83. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Extracellular vesicles (EVs) have been the focus of great interest, as they appear to be involved in numerous important cellular processes. They deliver bioactive macromolecules such as proteins, lipids, and nucleic acids, allowing intercellular communication in multicellular organisms. EVs are secreted by all cell types, including immune cells such as natural killer cells (NK), and they may play important roles in the immune system. Currently, a large-scale procedure to obtain functional NK EVs is lacking, limiting their use clinically. In this report, we present a simple, robust, and cost-effective method to isolate a large quantity of NK EVs. After propagating and activating NK cells ex vivo and then incubating them in exosome-free medium for 48 h, EVs were isolated using a polymer precipitation method. The isolated vesicles contain the tetraspanin CD63, an EV marker, and associated proteins (fibronectin), but are devoid of cytochrome C, a cytoplasmic marker. Nanoparticle tracking analysis showed a size distribution between 100 and 200 nm while transmission electron microscopy imaging displayed vesicles with an oval shape and comparable sizes, fulfilling the definition of EV. Importantly, isolated EV fractions were cytotoxic against cancer cells. Furthermore, our results demonstrate for the first time that isolated activated NK (aNK) cell EVs contain the cytotoxic proteins perforin, granulysin, and granzymes A and B, incorporated from the aNK cells. Activation of caspase -3, -7 and -9 was detected in cancer cells incubated with aNK EVs, and caspase inhibitors blocked aNK EV-induced cytotoxicity, suggesting that aNK EVs activate caspase pathways in target cells. The ability to isolate functional aNK EVs on a large scale may lead to new clinical applications. Abbreviations : NK: natural killer cells; activated NK (aNK) cells; EVs: extracellular vesicles; ALL: acute lymphoblastic leukaemia; aAPC: artificial antigen-presenting cell; TEM: transmission electron microscope; PBMC: peripheral blood mononuclear cells; FBS: foetal bovine serum.

Purpose: Immunotherapy of high-risk neuroblastoma using the anti-GD2 antibody dinutuximab induces antibody-dependent cell-mediated cytotoxicity (ADCC). Galunisertib, an inhibitor of TGFβR1, was examined for its ability to enhance the efficacy of dinutuximab in combination with human ex vivo activated NK (aNK) cells against neuroblastoma., Experimental Design: TGFB1 and TGFBR1 mRNA expression was determined for 249 primary neuroblastoma tumors by microarray analysis. The ability of galunisertib to inhibit SMAD activity induced by neuroblastoma patient blood and bone marrow plasmas in neuroblastoma cells was tested. The impact of galunisertib on TGFβ1-induced inhibition of aNK cytotoxicity and ADCC in vitro and on anti-neuroblastoma activity in NOD-scid gamma (NSG) mice was determined., Results: Neuroblastomas express TGFB1 and TGFBR1 mRNA. Galunisertib suppressed SMAD activation in neuroblastoma cells induced by exogenous TGFβ1 or by patient blood and bone marrow plasma, and suppressed SMAD2 phosphorylation in human neuroblastoma cells growing in NSG mice. In NK cells treated in vitro with exogenous TGFβ1, galunisertib suppressed SMAD2 phosphorylation and restored the expression of DNAM-1, NKp30, and NKG2D cytotoxicity receptors and the TRAIL death ligand, the release of perforin and granzyme A, and the direct cytotoxicity and ADCC of aNK cells against neuroblastoma cells. Addition of galunisertib to adoptive cell therapy with aNK cells plus dinutuximab reduced tumor growth and increased survival of mice injected with two neuroblastoma cell lines or a patient-derived xenograft., Conclusions: Galunisertib suppresses activation of SMAD2 in neuroblastomas and aNK cells, restores NK cytotoxic mechanisms, and increases the efficacy of dinutuximab with aNK cells against neuroblastoma tumors. Clin Cancer Res; 23(3); 804-13. ©2016 AACRSee related commentary by Zenarruzabeitia et al., p. 615., (©2016 American Association for Cancer Research.)

Neuroblastoma (NB) is the most common extracranial solid tumor in children. Our previous studies showed that the angiogenic integrin α v β 3 was increased in high-risk metastatic (stage 4) NB compared with localized neuroblastomas. Herein, we show that integrin α v β 3 was expressed on 68% of microvessels in MYCN-amplified stage 3 neuroblastomas, but only on 34% (means) in MYCN-non-amplified tumors ( p < 0.001; n = 54). PTEN, a tumor suppressor involved in α v β 3 signaling, was expressed in neuroblastomas either diffusely, focally or not at all (immunohistochemistry). Integrin α v β 3 was expressed on 60% of tumor microvessels when PTEN was negative or focal, as compared to 32% of microvessels in tumors with diffuse PTEN expression ( p < 0.001). In a MYCN transgenic mouse model, loss of one allele of PTEN promoted tumor growth, illustrating the potential role of PTEN in neuroblastoma pathogenesis. Interestingly, we report the novel dual PI-3K/BRD4 activity of SF1126 (originally developed as an RGD-conjugated pan PI3K inhibitor). SF1126 inhibits BRD4 bromodomain binding to acetylated lysine residues with histone H3 as well as PI3K activity in the MYCN amplified neuroblastoma cell line IMR-32. Moreover, SF1126 suppressed MYCN expression and MYCN associated transcriptional activity in IMR-32 and CHLA136, resulting in overall decrease in neuroblastoma cell viability. Finally, treatment of neuroblastoma tumors with SF1126 inhibited neuroblastoma growth in vivo . These data suggest integrin α v β 3 , MYCN/BRD4 and PTEN/PI3K/AKT signaling as biomarkers and hence therapeutic targets in neuroblastoma and support testing of the RGD integrin α v β 3 -targeted PI-3K/BRD4 inhibitor, SF1126 as a therapeutic strategy in this specific subgroup of high risk neuroblastoma., Competing Interests: CONFLICTS OF INTEREST Dr. Durden discloses financial conflict of interest in SignalRx Pharmaceuticals and in the SF1126 drug. The relationship between Dr. Durden and SignalRx has been internally reviewed and approved by the University of California, San Diego in accordance with its conflict of interest policies.

Neuroblastoma is the second most common solid tumor in children. Since the seminal discovery of the role of amplification of the MYCN oncogene in the pathogenesis of neuroblastoma in the 1980s, much focus has been on the contribution of genetic alterations in the progression of this cancer. However it is now clear that not only genetic events play a role but that the tumor microenvironment (TME) substantially contributes to the biology of neuroblastoma. In this article, we present a comprehensive review of the literature on the contribution of the TME to the ten hallmarks of cancer in neuroblastoma and discuss the mechanisms of communication between neuroblastoma cells and the TME that underlie the influence of the TME on neuroblastoma progression. We end our review by discussing how the knowledge acquired over the last two decades in this field is now leading to new clinical trials targeting the TME., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Introduction: Patients with high-risk neuroblastoma rarely succumb to their primary tumor but rather from relapsed metastatic disease after surgery. We, therefore, sought to create an in vivo model of minimal residual disease (MRD), which clinically replicates tumor recurrence and metastasis after surgical resection., Methods: Neuroblastoma cell lines CHLA-255, CHLA-136, and SH-SY5Y were used. After establishing orthotopic xenografts, mice were divided into control tumor group (sham operation at 14days) and tumor resection group (resection at 14days). Mice were monitored by bioluminescent imaging and sacrificed when institutional criteria for euthanasia were met., Results: In the CHLA-255 and CHLA-136 cell lines, mice experienced significantly longer survival following tumor resection (p<0.007). There was no survival benefit seen in the SH-SY5Y cell line (p=0.29). Bioluminescent imaging demonstrated metastatic disease in 100% of all tumor resection mice and varying rates of metastasis in control mice (4 of 5 CHLA-255, 2 of 4 CHLA-136, and 7 of 7 SH-SY5Y)., Conclusion: In this study, we describe a novel neuroblastoma model of MRD in mice. This MRD model serves as an innovative means to test preclinical therapies as well as elucidate mechanisms of metastatic disease in experimental neuroblastoma., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The molecular mechanisms underlying the aggressive behavior of MYCN driven neuroblastoma (NBL) is under intense investigation; however, little is known about the impact of this family of transcription factors on the splicing program. Here we used high-throughput RNA sequencing to systematically study the expression of RNA isoforms in stage 4 MYCN-amplified NBL, an aggressive subtype of metastatic NBL. We show that MYCN-amplified NBL tumors display a distinct gene splicing pattern affecting multiple cancer hallmark functions. Six splicing factors displayed unique differential expression patterns in MYCN-amplified tumors and cell lines, and the binding motifs for some of these splicing factors are significantly enriched in differentially-spliced genes. Direct binding of MYCN to promoter regions of the splicing factors PTBP1 and HNRNPA1 detected by ChIP-seq demonstrates that MYCN controls the splicing pattern by direct regulation of the expression of these key splicing factors. Furthermore, high expression of PTBP1 and HNRNPA1 was significantly associated with poor overall survival of stage4 NBL patients (p ≤ 0.05). Knocking down PTBP1, HNRNPA1 and their downstream target PKM2, an isoform of pro-tumor-growth, result in repressed growth of NBL cells. Therefore, our study reveals a novel role of MYCN in controlling global splicing program through regulation of splicing factors in addition to its well-known role in the transcription program. These findings suggest a therapeutically potential to target the key splicing factors or gene isoforms in high-risk NBL with MYCN-amplification., (Published by Elsevier Ireland Ltd.)

A more complete understanding of aberrant oncogenic signaling in neuroblastoma, a malignancy of the developing sympathetic nervous system, is paramount to improving patient outcomes. Recently, we identified LIN28B as an oncogenic driver in high-risk neuroblastoma. Here, we identify the oncogene RAN as a LIN28B target and show regional gain of chromosome 12q24 as an additional somatic alteration resulting in increased RAN expression. We show that LIN28B influences RAN expression by promoting RAN Binding Protein 2 expression and by directly binding RAN mRNA. Further, we demonstrate a convergence of LIN28B and RAN signaling on Aurora kinase A activity. Collectively, these findings demonstrate that LIN28B-RAN-AURKA signaling drives neuroblastoma oncogenesis, suggesting that this pathway may be amenable to therapeutic targeting., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: To evaluate BSO-mediated glutathione (GSH) depletion in combination with L-PAM for children with recurrent or refractory high-risk neuroblastoma (NB) as a means to enhance alkylator sensitivity., Procedure: This pilot study (NCI #T95-0092) administered L-S,R-buthionine sulfoximine (BSO) as a bolus followed by 72 hr continuous infusion of either 0.75 g/m(2)/hr (level 1) or 1.0 g/m(2)/hr (level 2) and melphalan (L-PAM) (15 mg/m(2) bolus at hour 48 of BSO infusion). GSH in blood mononuclear cells and bone marrow was measured by enzymatic assay, BSO in plasma by HPLC., Results: Thirty two patients received 58 courses of therapy (median 1, range 1-4 courses). Blood mononuclear cell GSH decreased (48 hr) to 47% ± 15.7%. Level 2 mean steady-state concentration (Css) for BSO = 524 ± 207 μM and peak L-PAM concentration = 3.32 ± 1.2 μM. Grade 3-4 leukopenia and thrombocytopenia were common. There were two deaths from CNS toxicity and acute tubular necrosis; one had a large, intracranial mass, both were receiving cephalosporin antibiotics. No other significant toxicities were seen. There were six responses (five partial and, one mixed) representing an 18% response rate; four/six responses occurred in patients that relapsed following myeloablative therapy and included a 98% reduction in volume (cm(3)) of a pelvic mass, and three/five patients with >3 log reduction of tumor in marrow as measured by immunocytology (sensitivity 1/10(5))., Conclusions: BSO/L-PAM has activity against recurrent high-risk NB. Exclusion of cephalosporin antibiotics in future clinical trials of BSO may diminish the potential for serious renal and CNS toxicity., (© 2015 Wiley Periodicals, Inc.)

Background: MYCN amplification with subsequent MYCN protein overexpression is a powerful indicator of poor prognosis of neuroblastoma patients. Little is known regarding the prognostic significance of the homologous MYC protein expression in neuroblastoma., Methods: Immunostaining for MYCN and MYC protein was performed on 357 undifferentiated/poorly differentiated neuroblastomas. Results were analysed with other prognostic markers., Results: Sixty-seven (19%) tumours were MYCN(+), 38 (11%) were MYC(+), and one(0.3%) had both proteins(+). MYCN(+) tumours and MYC(+) tumours were more likely diagnosed in children>18months with stage4-disease. MYCN(+) tumours were associated with amplified MYCN, Unfavourable Histology (UH), and High-MKI (Mitosis-Karyorrhexis Index). MYC(+) tumours were also frequently UH but not associated with MYCN amplification, and more likely to have low-/intermediate-MKI. Favourable Histology patients without MYC/MYCN expressions exhibited the best survival (N=167, 89.7±5.5% 3-year EFS, 97.0±3.2% 3-year OS), followed by UH patients without MYC/MYCN expressions (N=84, 63.1±13.6% 3-year EFS, 83.5±9.4% 3-year OS). MYCN(+)patients and MYC(+)patients had similar and significantly low (P<0.0001) survivals (46.2±12.0% 3-year EFS, 63.2±12.1% 3-year OS and 43.4±23.1% 3-year EFS, 63.5±19.2% 3-year OS, respectively). Notably, the prognostic impact imparted by MYC expression was independent from other markers., Conclusions: In this series, ∼30% of neuroblastomas had augmented MYCN or MYC expression with dismal survivals. Prospective study of MYC/MYCN protein expression signature as a new biomarker for high-risk neuroblastomas should be conducted.

Background: How exosomic microRNAs (miRNAs) contribute to the development of drug resistance in the context of the tumor microenvironment has not been previously described in neuroblastoma (NBL)., Methods: Coculture experiments were performed to assess exosomic transfer of miR-21 from NBL cells to human monocytes and miR-155 from human monocytes to NBL cells. Luciferase reporter assays were performed to assess miR-155 targeting of TERF1 in NBL cells. Tumor growth was measured in NBL xenografts treated with Cisplatin and peritumoral exosomic miR-155 (n = 6 mice per group) CD163, miR-155, and TERF1 levels were assessed in 20 NBL primary tissues by Human Exon Arrays and quantitative real-time polymerase chain reaction. Student's t test was used to evaluate the differences between treatment groups. All statistical tests were two-sided., Results: miR-21 mean fold change (f.c.) was 12.08±0.30 (P < .001) in human monocytes treated with NBL derived exosomes for 48 hours, and miR-155 mean f.c. was 4.51±0.25 (P < .001) in NBL cells cocultured with human monocytes for 48 hours. TERF1 mean luciferase activity in miR-155 transfected NBL cells normalized to scrambled was 0.36 ± 0.05 (P <.001). Mean tumor volumes in Dotap-miR-155 compared with Dotap-scrambled were 322.80±120mm(3) and 76.00±39.3mm(3), P = .002 at day 24, respectively. Patients with high CD163 infiltrating NBLs had statistically significantly higher intratumoral levels of miR-155 (P = .04) and lower levels of TERF1 mRNA (P = .02)., Conclusions: These data indicate a unique role of exosomic miR-21 and miR-155 in the cross-talk between NBL cells and human monocytes in the resistance to chemotherapy, through a novel exosomic miR-21/TLR8-NF-кB/exosomic miR-155/TERF1 signaling pathway., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)