NB Cells Research Articles

CircRANBP17 modulated KDM1A to regulate neuroblastoma progression by sponging miR-27b-3p.

Neuroblastoma (NB) is a common childhood cancer. Circular RNA RAN binding protein 17 (circRANBP17) has been identified to participate in diverse tumor progression. This study aims to explore the function and mechanism of circRANBP17 in NB. The levels of circRANBP17, miR-27b-3p and KDM1A in NB tissues and cells were measured by qRT-PCR. Mouse model assay was performed to investigate the effect of circRANBP17 knockdown on tumor formation in vivo. The levels of circRANBP17 and KDM1A were significantly up-regulated, and the level of miR-27b-3p was strikingly down-regulated in NB tissues and cells (SK-N-SH and SK-N-AS). Functional studies indicated that miR-27b-3p inhibitor mitigated the inhibitory effects on cell proliferation, migration, invasion and the promoting effect on cell apoptosis in SK-N-SH and SK-N-AS cells induced by circRANBP17 knockdown. Also, miR-27b-3p regulated NB cell malignancy by targeting KDM1A. Further studies revealed that miR-27b-3p inhibitor reversed the low expression of KDM1A induced by circRANBP17 knockdown. In support, circRANBP17 knockdown led to inhibition of tumor formation in vivo. In conclusion, circRANBP17 modulated KDM1A to promote cell proliferation, migration, invasion and restrain cell apoptosis in NB by sponging miR-27b-3p, and the new regulatory network may provide a theoretical basis for the further study of NB.

YY1 transcription factor induces proliferation and aerobic glycolysis of neuroblastoma cells via LDHA regulation.

The present study investigated the effect of transcription factor yin yang 1 (YY1) on aerobic glycolysis and cell proliferation in neuroblastoma and its mechanism. Neuroblastoma cell lines were used to investigate the association between YY1 and lactate dehydrogenase A (LDHA) expression. Cell Counting Kit (CCK)-8 and clone formation experiments were used to detect the cell viability. The interaction of YY1 and LDHA was detected using chromatin immunoprecipitation assay. Glucose uptake, intra/extracellular lactate and pyruvate and LDHA expression were evaluated using standard methods. Reverse transcription quantitative PCR, western blotting and gene overexpression or silencing were undertaken to explore the biological effects and underlying mechanisms of transcriptional regulators in NB cells. The results demonstrated that YY1 was significantly upregulated in neuroblastoma cell lines. The results of aerobic glycolysis and CCK-8 indicated that YY1 significantly promoted the proliferation and aerobic glycolysis of neuroblastoma cells. In addition, chromatin immunoprecipitation-PCR results demonstrated that YY1 was directly bound to the promoter LDHA. Overexpression of LDHA could reverse the inhibitory effect of sh-YY1 on aerobic glycolysis and proliferation of neuroblastoma cells. In conclusion, YY1 could induce aerobic glycolysis and proliferation of neuroblastoma cell lines, and may directly mediate the regulation of LDHA. These findings may provide novel insight for the treatment of neuroblastoma.

Reduction of LPAR1 Expression in Neuroblastoma Promotes Tumor Cell Migration.

Simple SummaryThe tumor metastasis in the bone marrow or other organs in high-risk neuroblastoma patients is a serious problem to tackle and strongly impairs the survival of patients. Novel and effective targets for the treatment of neuroblastoma, especially tumor metastasis, need to be explored. Using multiple databases and analysis methods, LPAR1 was screened out through our comprehensive bioinformatics analysis and found to be positively associated with survival of neuroblastoma patients. LPAR1 was proved to be reduced in neuroblastoma cells compared with non-mailgant cells. LPA-LPAR1 axis showed migration-inhibitory effects on neuroblastoma cells, suggesting that LPAR1 may be a potential target for future treatment of neuroblastoma.Neuroblastoma is the most common extracranial solid tumor in children. Tumor metastasis in high-risk NB patients is an essential problem that impairs the survival of patients. In this study, we aimed to use a comprehensive bioinformatics analysis to identify differentially expressed genes between NB and control cells, and to explore novel prognostic markers or treatment targets in tumors. In this way, FN1, PIK3R5, LPAR6 and LPAR1 were screened out via KEGG, GO and PPI network analysis, and we verified the expression and function of LPAR1 experimentally. Our research verified the decreased expression of LPAR1 in NB cells, and the tumor migration inhibitory effects of LPA on NB cells via LPAR1. Moreover, knockdown of LPAR1 promoted NB cell migration and abolished the migration-inhibitory effects mediated by LPA-LPAR1. The tumor-suppressing effects of the LPA-LPAR1 axis suggest that LPAR1 might be a potential target for future treatment of NB.

Field exposure to 50 Hz significantly affects wild-type and unfolded p53 expression in NB69 neuroblastoma cells.

Previous studies have shown that intermittent exposure to a 50 Hz, 100 µT sinusoidal magnetic field (MF) promotes proliferation of human neuroblastoma cells, NB69. This effect is mediated by activation of the epidermal growth factor receptor through a free radical-dependent activation of the p38 pathway. The present study investigated the possibility that the oxidative stress-sensitive protein p53 is a potential target of the MF, and that field exposure can affect the protein expression. To that end, NB69 cells were exposed to short intervals of 30 to 120 min to the aforementioned MF parameters. Two specific anti-p53 antibodies that allow discrimination between the wild and unfolded forms of p53 were used to study the expression and cellular distribution of both isoforms of the protein. The expression of the antiapoptotic protein Bcl-2, whose regulation is mediated by p53, was also analyzed. The obtained results revealed that MF exposure induced increases in p53 gene expression and in protein expression of the wild-type form of p53. Field exposure also caused overexpression of the unfolded form of p53, together with changes in the nuclear/cytoplasmic distribution of both forms of the protein. The expression of protein Bcl-2 was also significantly increased in response to the MF. As a whole, these results indicated that the MF is capable of interacting with the function, distribution and conformation of protein p53. Such interactions could be involved in previously reported MF effects on NB69 proliferation promotion.

Silencing of Circ_0135889 Restrains Proliferation and Tumorigenicity of Human Neuroblastoma Cells

IntroductionNeuroblastoma (NB) is the most common extracranial solid tumor in infants and young children. Circular ribonucleic acid (RNA) hsa_circ_0135889 (circ_0135889; hsa_circ argonaute 2 _001) is highly expressed in multiple cancer tissues, including NB. However, its role in tumor progression of NB was unclear. MethodsReal-time quantitative polymerace chain reaction was used to detect RNA expression, and western blotting, or immunohistochemistry was used to measure protein expression. Functional experiments were performed using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, 5-Ethynyl-2’- deoxyuridine, Annexin V-fluorescein isothiocyanate/propidium iodide, and transwell assays, as well as xenograft tumor model. The intermolecular interaction was predicted by online databases and confirmed by dual-luciferase reporter assay and RNA pull-down assay. ResultsCirc_0135889 and neuronal differentiation 1 (NEUROD1) were upregulated whilst microRNA (miR)-127-5p, was downregulated in NB tumors and immortalized NB cells. Silencing of circ_0135889 could suppress cell proliferation, migration and invasion, but enhance apoptosis rate of NB cells in vitro. More importantly, circ_0135889 depletion inhibited xenograft tumor growth of NB cells. Circ_0135889 was a sponge for miR-127-5p, and inhibition of miR-127-5p counteracted the inhibitory impact of circ_0135889 knockdown on the malignant behaviors of NB cells. Moreover, NEUROD1 was a direct target of miR-127-5p, and miR-127-5p exerted the anti-tumor role in NB cells by targeting NEUROD1. Furthermore, circ_0135889 regulated NEUROD1expression by sponging miR-127-5p. ConclusionsCirc_0135889 promoted the tumorigenicity of NB by regulating miR-127-5p/NEUROD1 axis, which might provide a promising therapeutic target for NB.

TTF1 suppresses neuroblastoma growth and induces neuroblastoma differentiation by targeting TrkA and the miR-204/TrkB axis

SummaryNeuroblastoma (NB) is the most common extracranial malignant solid tumor in children. We found that TTF1, TrkA, and miR-204 were lowly expressed, whereas TrkB was highly expressed in undifferentiated NB tissues. Meanwhile, TTF1 expression correlated positively with TrkA and miR-204 expression but negatively with TrkB expression. The TTF1 promoter was hypermethylated in undifferentiated NB tissues and SK-N-BE cells, leading to TTF1 downregulation. We also identified miR-204, which directly targets TrkB, as a transcriptional target of TTF1. Functionally, TTF1 suppressed proliferation, migration, and invasion of NB cells, whereas induced cell cycle arrest, apoptosis, and autophagy of NB cells by regulating TrkA and the miR-204-TrkB axis. Furthermore, TTF1 suppressed tumor growth and promoted neurogenic differentiation in a NB xenograft mouse model. Our study demonstrates that TTF1 reduces tumor growth and induces neurogenic differentiation in NB by directly targeting TrkA and the miR-204/TrkB axis.

Active legumain promotes invasion and migration of neuroblastoma by regulating epithelial-mesenchymal transition.

Neuroblastoma (NB) is a commonly occurring malignancy in children. Epithelial-mesenchymal transition (EMT) is an adaptive change in promoting tumor metastasis. As an important factor in regulating tumor metastasis, whether legumain could promote metastasis of NB by EMT is still unexplored. Legumain is the active form of prolegumain, abundant in tumor plasma. So in the current study, different forms of legumain were identified in NB. Second, correlation analysis of N-cadherin and active legumain was identified by western blot analysis. Third, legumain gene amplification or gene knockdown were proceeded to examine the effect of legumain on EMT by scratch and transwell assay; meanwhile, active mature legumain or its asparagine endopeptidase (AEP) inhibitor was also added in. Finally, legumain can be detected differently in NB cells. Changes in legumain could influence NB metastasis by regulating EMT markers (e.g., N-cadherin, vimentin, and slug). Besides, the effect of legumain on EMT by its AEP activity was proved by intervention experiment of AEP gene transfection and gene knockdown experiments or adding recombinant human legumain suspension or specific inhibitor of AEP in NB cells (p < 0.05). These results suggest that legumain can promote invasion and migration of NB by regulating EMT, and EMT of NB is regulated by AEP activity of legumain, which can be inhibited by a specific AEP inhibitor.

Abstract 2012: A humanized anaplastic lymphoma kinase (ALK)-directed antibody-drug conjugate (ADC) demonstrates potent cytotoxicity in neuroblastoma (NBL) and fusion positive rhabdomyosarcoma (FP RMS)

Abstract Introduction: ALK is a lineage restricted oncoprotein expressed on the cell surface of NBL as wild-type (WT), mutated, or amplified, and recently shown to be overexpressed in FP RMS. Small molecule inhibitors have shown potent efficacy in NBL with ALK mutations or amplifications, but is limited to a minority of the high-risk population and have demonstrated conferred resistance. We have previously shown the potential of an ADC approach for WT ALK-expressing NBL with a chimeric ALK-directed ADC CDX-0125. Methods: A highly specific humanized ALK antibody KTN0239 was developed with site-specific conjugation of an amine-azido linker conjugated to pyrrolobenzodiazepine (PBD) dimers or duocarmycin using click chemistry. ALK surface expression in ALK amplified (NB-1), WT non-amplified (IMR-32), mutant (Felix, SH-SY5Y, Kelly, NB1-643), and WT null (SK-N-AS) cell lines were quantified with flow cytometry using the primary KTN0239 antibody. Internalization kinetics of KTN0239 were measured using Incucyte® Fabflour-pH labeling. In vitro ADC IC50 values and viability rescue were assessed with a CellTiter-Glo® assay with ADC concentrations ranging from 10 fM to 10 nM. Western blot was used to elucidate cytotoxic mechanism of the ADC. Results: ALK surface protein molecule expression was 21,820 in NB-1 cells, 3,708 in Felix, and 1,426 in SK-N-AS cells. KTN0239 was internalized into NB1 cells with a logarithmic trend, with &amp;gt;65% of antibody internalized within 8 hours. NB-1 cell line viability was rescued to &amp;gt;80% when 2.5 nM of KTN0239 was in competition with the PBD-conjugated ADC at the IC50 concentration. The ADC induced activation of PARP, caspase-3, and γH2AX without attenuation of ALK signaling in NB-1 cells. Conclusions: ADCs directed to ALK-expressing cancers are a promising therapeutic approach. The efficacy of the ADCs are currently being tested in NBL and FP RMS mouse models, and will be reported. Mean IC50 values (pM) of ADCs with a drug antibody ratio (DAR) of 6 in NBL cell lines ADC: PBD-conjugated Duocarmycin-conjugated NB-1 14 71 IMR-32 12 741 Felix 51 110 NB-1643 6.6 1,196 Kelly 517 34,700 SH-SY5Y 693 3,024 SK-N-AS 533 1,420 Citation Format: Alberto D. Guerra, Annie Kennedy, Cynthia Adams, Rawan Shraim, Amber K. Weiner, Chuan Chen, Kateryna Krytska, Colleen Larmour, Smita Matkar, Dimiter Dimitrov, Dontcho V. Jelev, Yael P. Mossé. A humanized anaplastic lymphoma kinase (ALK)-directed antibody-drug conjugate (ADC) demonstrates potent cytotoxicity in neuroblastoma (NBL) and fusion positive rhabdomyosarcoma (FP RMS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2012.

Abstract 164: Oncogenic PKC-ι/PKC-ζ/14-3-3 and PKC-ι/PKC-ζ/Smad2/3 signaling cascades are crucial for increased invasiveness of Neuroblastoma cells

Abstract Neuroblastoma (NB) is a the pediatric cancer of the early nerve cells in which solid tumors originate from the peripheral sympathetic nervous system and as such can occur primarily anywhere along the sympathetic chain with development on the adrenal gland being most common. The expression of the disease is highly variable as in some cases lead to spontaneously regression without any medical intervention whereas in other cases the tumors become highly metastatic and therapeutically resistant. Our results demonstrated that atypical protein kinase C-iota and zeta (aPKC-ι/ζ) levels were overexpressed in NB cells (BE-2C and BE-M17) and tissues. The present study shows the downstream effects PKC-ι specific inhibitor 5-amino-1-(2,3-dihydroxy-4-(hydroxymethyl)cyclopentyl)-1H-imidazole-4-carboxamide (ICA-1S) and a PKC-ζ specific inhibitor 8-hydroxy-1,3,6-naphthalenetrisulfonic acid (ζ-Stat) on aPKCs, 14-3-3, p-14-3-3, Akt1, NF-κB p65, Smad2/3 and p-Smad2/3. Decreased Vimentin and increased E-cadherin levels indicated the downregulation of epithelial-mesenchymal transition (EMT). Result also indicated that SNAIL1 transcriptional activity was downregulated as a result of aPKC diminution. SNAIL1 is known to induce EMT. 14-3-3 proteins have the ability to bind a multitude of functionally diverse signaling proteins, including kinases, phosphatases, and transmembrane receptors. Our immunoprecipitation (IP) data suggested that both aPKCs associate with 14-3-3 and Smad2/3. Our data also indicated that both 14-3-3 and Smad2/3 levels were significantly decreased as a result of aPKC inhibition. In addition, pIκB, NFκB p65, p-14-3-3, pAkt1, levels were significantly decreased. Our data indicates that 14-3-3 acts as a central key regulator in aPKC driven cell cycle progression in BE-2C and BE-M17 cells. In addition, we found that Smad2/3 plays a vital role in upregulation of aPKC driven Vimentin dynamics in NB cell lines in relation to 14-3-3. In-vitro migration/invasion assays, IP, immunofluorescence, real time qPCR and Western blot techniques were used to further analyze role of aPKCs in NB malignancy. Data confirmed that aPKC attenuation triggers multiple pro-apoptotic signaling cascades through downregulation of NFκB, Akt, and Smad pathways through downregulation of 14-3-3. In-vivo experiments on murine models are being conducted using ICA-1S and ζ-Stat. Excised tumors will be analyzed for pathways observed in in-vitro experiments. Overall results suggest that aPKCs are crucial for increased invasiveness in NB. Results suggested that aPKC can be targeted to develop customized, tailored therapies for NB which merit further research. Citation Format: Sloan Breedy. Oncogenic PKC-ι/PKC-ζ/14-3-3 and PKC-ι/PKC-ζ/Smad2/3 signaling cascades are crucial for increased invasiveness of Neuroblastoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 164.

Abstract 2018: Therapeutic benefit of dual ALK and FAK inhibition in neuroblastoma

Abstract Neuroblastoma (NB) is the most common extracranial pediatric tumor, and accounts for approximately 12% of cancer-related deaths in children. Though several genomic drivers have been identified, the development of targeted therapy for treating this aggressive pediatric malignancy has yet to be realized. Thus, there exists an urgent need to develop alternative therapeutic strategies for treating aggressive and metastatic NB. One novel approach is to therapeutically target anaplastic lymphoma kinase (ALK) and focal adhesion kinase (FAK), which are multi-functional tyrosine kinases implicated in neural development and play an important role in growth and metastasis of several cancers. Genomic aberrations of ALK such as overexpression, amplifications, and mutations, have been reported in NB. The role of FAK has also been delineated in NB as well as associated with disease metastasis. Using in silico analysis of sequencing data from NB patients procured from Pediatric MI-ONCOSEQ (precision oncology program), we found a cohort of patients that express high ALK and FAK expression. Given the potential roles of ALK and FAK in NB, we evaluated the efficacy of a novel compound ESK440, which is a dual ALK and FAK inhibitor. ESK440 has passed Phase 1 clinical trials in adult patients with solid tumors. It is capable of crossing the blood brain barrier and binds to several mutated forms of ALK, thus making ESK440 an attractive therapeutic candidate for treating NB. A wide panel of NB cancer cell lines were screened with ESK440, and a CellTiter-Glo® Luminescent Cell Viability Assay was used to determine the IC-50s. Our results revealed that NB cells with ALK genomic aberrations (mutations and amplifications) showed low IC-50 values. Further, treatment with ESK440 inhibited ALK and FAK associated signaling pathways. We also observed decreased expression of MYCN. Intriguingly, ESK440 studies in NB xenograft model (NB-1) resulted in tumor regression in treated animals. Altogether, our study has discovered the therapeutic potential of dual ALK and FAK inhibitor in NB, and our findings may provide the foundation for initiating clinical trials targeting this disease in pediatric patients. Citation Format: Seema Chugh, Jean C. Tien, Jennifer Hon, Pushpinder Singh Bawa, Carson Kenum, Chi Chiang Li, Yunhui Cheng, Andrew D. Delekta, Jae Eun Choi, Rahul Mannan, Yuanyuan Qiao, Rajen Mody, Arul Chinnaiyan. Therapeutic benefit of dual ALK and FAK inhibition in neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2018.

1317-P: Intermittent Hypoxia Increased the Expression of DBH and PNMT in Neuronal Cells via MicroRNA-Mediated Mechanism

Sleep apnea syndrome (SAS) , characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia [IH]) , is a risk factor for hypertension and insulin resistance. We have reported correlation between IH and insulin resistance. However, why hypertension is induced by IH has been elusive. Here, we investigated the effect of IH on the expression of catecholamine metabolizing enzymes using in vitro IH system. Human and mouse neuronal cells, NB-1 and Neuro-2a, were exposed to IH (70 cycles of 5 min hypoxia [1% O2] and min normoxia [21% O2]) or normoxia for 24 hours. Real-time RT-PCR revealed that IH significantly increased the mRNA levels of dopamine β-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in both NB-1 (P=0.0271 and P&amp;lt;0.0001, respectively) and Neuro-2a (P=0.0135 and P=0.0341, respectively) . Western blot showed that the expression of DBH and PNMT in the NB-1 cells significantly increased by IH (P=0.0296 and P=0.0007, respectively) . We next prepared reporter plasmids containing human DBH (-1018˜+10) and PNMT (-600˜+67) upstream of luciferase reporter gene and transfected them into NB-1 cells. The promoter activities of these genes were not increased by IH. Target mRNA search of microRNA (miR) s using MicroRNA.org program revealed that the mRNAs have a potential target sequence for miR-375. The miR-375 level of IH-treated cells was significantly decreased than that of normoxia-treated cells (P=0.0222) . To clarify the role of miR-375, miR-375 mimic and non-specific control RNA (miR-375 mimic NC) were introduced into NB-1 cells. The IH-induced up-regulation of mRNAs of DBH and PNMT was abolished by introduction of miR-375 mimic but not by miR-375 mimic NC. Theses results strongly suggest that IH stress down-regulates the miR-375 in neuronal cells, resulting in the increased levels of DBH and PNMT via the inhibition of the miR-375-mediated mRNA degradation, leading SAS patients to hypertension. Disclosure S.Takasawa: None. R.Shobatake: None. Y.Takeda: None. T.Uchiyama: None. A.Yamauchi: None. M.Makino: None. K.Asai: None. H.Ota: None.

Intermittent Hypoxia Increased the Expression of DBH and PNMT in Neuroblastoma Cells via MicroRNA-375-Mediated Mechanism.

Sleep apnea syndrome (SAS), characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia (IH)), is a risk factor for hypertension and insulin resistance. We report a correlation between IH and insulin resistance/diabetes. However, the reason why hypertension is induced by IH is elusive. Here, we investigated the effect of IH on the expression of catecholamine-metabolizing enzymes using an in vitro IH system. Human and mouse neuroblastoma cells (NB-1 and Neuro-2a) were exposed to IH or normoxia for 24 h. Real-time RT-PCR revealed that IH significantly increased the mRNA levels of dopamine β-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in both NB-1 and Neuro-2a. Western blot showed that the expression of DBH and PNMT in the NB-1 cells was significantly increased by IH. Reporter assays revealed that promoter activities of DBH and PNMT were not increased by IH. The miR-375 level of IH-treated cells was significantly decreased relative to that of normoxia-treated cells. The IH-induced up-regulation of DBH and PNMT was abolished by the introduction of the miR-375 mimic, but not by the control RNA. These results indicate that IH stress increases levels of DBH and PNMT via the inhibition of miR-375-mediated mRNA degradation, potentially playing a role in the emergence of hypertension in SAS patients.

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

BackgroundNeuroblastoma (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.ResultsIn 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.ConclusionGNE987 destroyed the abnormal transcriptional regulation of oncogenes in NB by downregulating BRD4, which could be a potential therapeutic candidate for NB.

Photodynamic therapy with 5-aminolevulinic acid: A new diagnostic, therapeutic, and surgical aid for neuroblastoma

Background5-Aminolevulinic acid (ALA)-based photodynamic therapy (PDT) is widely used in cancer therapy because of the tumor-specific accumulation of photosensitizing protoporphyrin IX (PpIX). We aimed to assess the susceptibility of human neuroblastoma cell lines to ALA-PDT and determine the mechanism of PDT. MethodsWe used four human neuroblastoma cell lines (GOTO, NB9, IMR32, and NB1) and a gastric cancer cell line (MKN45) as a positive control. Cells were treated with increasing concentrations of ALA, and the ALA-induced production of PpIX in tumor cells was quantified using fluorescence spectrophotometry. PDT photocytotoxicity was measured by exposing the cells to a 630-nm irradiation for 10 min, and apoptotic cells stained with phosphatidylserine (PS) and propidium iodide (PI) were detected through flow cytometry. ResultsALA cytotoxicity was not observed in any cell line. The intracellular concentration of PpIX increased in an ALA dose-dependent manner, and intracellular fluorescence of PpIX increased in a time-dependent manner. The viability of NB-1 cells treated with 250 μM 5-ALA rapidly decreased to 5%. Photocytotoxicity was observed in the following order: NB1, IMR32, NB-9, and GOTO. Photocytotoxicity was positively correlated with intracellular PpIX concentrations. PS+/PI- cells increased up to 21% after 12 h, and PS+/PI+ cells accounted for 35% of all cells after 24 h, which suggests that ALA-PDT induced apoptotic cell death. ConclusionThis study shows that neuroblastoma cell lines were susceptible to 5-ALA-PDT, resulting in persistent apoptotic cell death. Levels of evidenceN/A for basic study.

Licochalcone E inhibits trxR1 expression, alters Nrf2/STAT6 signal, and induces antitumor effects in vitro against human SH‐SY5Y and SK‐N‐BE(2) neuroblastoma cells

AbstractNeuroblastoma (NB) is the most common solid tumor of the sympathetic nervous system (SNS) arising in childhood less than 15 years age. Licochalcone (Lic) is known to show inhibitory effects in cancer growth, and there has evidence suggested that Lic A inhibits hypoxic induced NB SK‐N‐SH cell proliferation. However, it is unclear whether LicE exerts similar effects in NB and the associated molecular mechanism of Lic in neuroblastoma is still unclear. In the current study, we found that LicE at the concentration 2, 4 and 6 μM all induced a profound reduction in cell viability, colony formation and cell proliferation. Next, LicE treatment effectively promoted cell apoptosis, inhibited cell migration and invasion. LicE significantly suppressed trxR1 expression, activated Nrf2 expression and inhibited STAT6 expression in SH‐SY5Y and SK‐N‐BE(2) NB cells. We further identified that trxR1, STAT6 overexpression or Nrf2 silence reversed the antitumor effects of LicE in human SH‐SY5Y and SK‐N‐BE(2) NB cells. Finally, LicE treatment significantly inhibited tumor growth in nude mice carrying a SK‐N‐SH cell xenograft. These results provide new insights into the effects and highlighting a novel mechanism of LicE through regulating trxR1/Nrf2/STAT6 signal pathway in NB.

Comparison of three different methods to detect bone marrow involvement in patients with neuroblastoma

PurposeNeuroblastoma (NB) is the most frequent extracranial tumor in children. The detection of bone marrow (BM) involvement is crucial for correct staging and risk-adapted treatment. We compared three methods regarding the detection of NB involvement in BM.MethodsEighty-one patients with NB were included in this retrospective study. BM samples were obtained at designated time points at study entry and during treatment or follow-up. The diagnostic tools for BM analysis included cytomorphology (CM), flow cytometry (FCM) and automatic immunofluorescence plus fluorescence in situ hybridization (AIPF).ResultsWe analyzed 369 aspirates in 81 patients in whom AIPF, CM, and FCM were simultaneously available. During the observation period, NB cells were detected in 86/369 (23.3%) cases, by CM in 32/369 (8.7%), by FCM in 52 (14.1%), and by AIPF in 72 (19.5%) samples. AIPF and/or FCM confirmed all positive results obtained in CM and detected 11 additional positive BM aspirates in 294 CM negative samples (p < 0,001). Survival of patients with BM involvement at study entry identified solely by FCM/AIPF was 17.4% versus 0% for patients in whom BM involvement was already identified by CM.ConclusionThe combination of AIPF/FCM yielded the highest detection rate of NB cells in BM. AIPF was the single, most sensitive method in detecting these cells. Although CM did not provide any additional positive results, it is still a useful, readily available and cost-effective tool. The prognostic significance of FCM and AIPF should be confirmed in a prospective study with a larger number of patients.

Synergistic efficacy of inhibiting MYCN and mTOR signaling against neuroblastoma

BackgroundNeuroblastoma (NB) patients with MYCN amplification or overexpression respond poorly to current therapies and exhibit extremely poor clinical outcomes. PI3K-mTOR signaling-driven deregulation of protein synthesis is very common in NB and various other cancers that promote MYCN stabilization. In addition, both the MYCN and mTOR signaling axes can directly regulate a common translation pathway that leads to increased protein synthesis and cell proliferation. However, a strategy of concurrently targeting MYCN and mTOR signaling in NB remains unexplored. This study aimed to investigate the therapeutic potential of targeting dysregulated protein synthesis pathways by inhibiting the MYCN and mTOR pathways together in NB.MethodsUsing small molecule/pharmacologic approaches, we evaluated the effects of combined inhibition of MYCN transcription and mTOR signaling on NB cell growth/survival and associated molecular mechanism(s) in NB cell lines. We used two well-established BET (bromodomain extra-terminal) protein inhibitors (JQ1, OTX-015), and a clinically relevant mTOR inhibitor, temsirolimus, to target MYCN transcription and mTOR signaling, respectively. The single agent and combined efficacies of these inhibitors on NB cell growth, apoptosis, cell cycle and neurospheres were assessed using MTT, Annexin-V, propidium-iodide staining and sphere assays, respectively. Effects of inhibitors on global protein synthesis were quantified using a fluorescence-based (FamAzide)-based protein synthesis assay. Further, we investigated the specificities of these inhibitors in targeting the associated pathways/molecules using western blot analyses.ResultsCo-treatment of JQ1 or OTX-015 with temsirolimus synergistically suppressed NB cell growth/survival by inducing G1 cell cycle arrest and apoptosis with greatest efficacy in MYCN-amplified NB cells. Mechanistically, the co-treatment of JQ1 or OTX-015 with temsirolimus significantly downregulated the expression levels of phosphorylated 4EBP1/p70-S6K/eIF4E (mTOR components) and BRD4 (BET protein)/MYCN proteins. Further, this combination significantly inhibited global protein synthesis, compared to single agents. Our findings also demonstrated that both JQ1 and temsirolimus chemosensitized NB cells when tested in combination with cisplatin chemotherapy.ConclusionsTogether, our findings demonstrate synergistic efficacy of JQ1 or OTX-015 and temsirolimus against MYCN-driven NB, by dual-inhibition of MYCN (targeting transcription) and mTOR (targeting translation). Additional preclinical evaluation is warranted to determine the clinical utility of targeted therapy for high-risk NB patients.

Molecular Iodine/Cyclophosphamide Synergism on Chemoresistant Neuroblastoma Models.

Neuroblastoma (Nb), the most common extracranial tumor in children, exhibited remarkable phenotypic diversity and heterogeneous clinical behavior. Tumors with MYCN overexpression have a worse prognosis. MYCN promotes tumor progression by inducing cell proliferation, de-differentiation, and dysregulated mitochondrial metabolism. Cyclophosphamide (CFF) at minimum effective oral doses (metronomic therapy) exerts beneficial actions on chemoresistant cancers. Molecular iodine (I2) in coadministration with all-trans retinoic acid synergizes apoptosis and cell differentiation in Nb cells. This work analyzes the impact of I2 and CFF on the viability (culture) and tumor progression (xenografts) of Nb chemoresistant SK-N-BE(2) cells. Results showed that both molecules induce dose-response antiproliferative effects, and I2 increases the sensibility of Nb cells to CFF, triggering PPARγ expression and acting as a mitocan in mitochondrial metabolism. In vivo oral I2/metronomic CFF treatments showed significant inhibition in xenograft growth, decreasing proliferation (Survivin) and activating apoptosis signaling (P53, Bax/Bcl-2). In addition, I2 decreased the expression of master markers of malignancy (MYCN, TrkB), vasculature remodeling, and increased differentiation signaling (PPARγ and TrkA). Furthermore, I2 supplementation prevented loss of body weight and hemorrhagic cystitis secondary to CFF in nude mice. These results allow us to propose the I2 supplement in metronomic CFF treatments to increase the effectiveness of chemotherapy and reduce side effects.

Prolyl oligopeptidase participates in the cytosine arabinoside-induced nuclear translocation of glyceraldehyde 3-phosphate dehydrogenase in a human neuroblastoma cell line

Previously, we reported that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a binding partner of prolyl oligopeptidase (POP) in neuroblastoma NB-1 cells and that the POP inhibitor, SUAM-14746, inhibits cytosine arabinoside (Ara-C)-induced nuclear translocation of GAPDH and protects against Ara-C cytotoxicity. To carry out a more in-depth analysis of the interaction between POP and GAPDH, we generated POP-KO NB-1 cells and compared the nuclear translocation of GAPDH after Ara-C with or without SUAM-14746 treatment to wild-type NB-1 cells by western blotting and fluorescence immunostaining. Ara-C did not induce the nuclear translocation of GAPDH and SUAM-14746 did not protect against Ara-C cytotoxicity in POP-KO cells. These results indicate that the anticancer effects of Ara-C not only include the commonly known antimetabolic effects, but also the induction of cell death by nuclear transfer of GAPDH through interaction with POP.

Abstract 1544: Generation of ALK CAR-T cells for neuroblastoma therapy

Abstract Neuroblastoma (NB) is the most deadly cancer in children with dismal survival in high-risk patients. The majority of NB express the full length anaplastic lymphoma kinase (ALK) receptor, that typically acts as driver oncogene together with MYCN. In contrast to ALK-driven lung cancer or lymphoma, targeted therapies with ALK tyrosine kinase inhibitors (TKIs), despite encouraging, induce only partial responses in NB. Therefore, additional tools to improve NB treatment are strongly needed. To specifically target NB cells, we developed a series of ALK chimeric antigen receptor (CAR) T constructs from antibodies that recognize both human and mouse ALK. Murine ALK CAR-T cells are able to control the growth of ALK+ leukemia and NB in syngeneic tumor models without detectable toxicity. From the leading candidate, we generated fully humanized ALK CAR-T cells that showed potent in vitro killing activity against a large panel of human NB lines, with activity comparable to GD2 CAR-T cells that are currently in clinical trials for NB patients. Remarkably, ALK CAR-T treatment synergized in vivo with the ALK inhibitor lorlatinib. Mechanistically, lorlatinib not only reduced tumor growth, but enhanced ALK expression on the surface of tumor cells, thereby facilitating ALK CAR-T targeting. Combination of ALK CAR-T cells with lorlatinib resulted in enhanced killing of NB cells and cure or markedly increased survival in mouse models of human metastatic NB even with low ALK expression. These findings support the clinical development of ALK CAR-T cells for NB therapy. Citation Format: Elisa Bergaggio, Wei-Tien Tai, Andrea Aroldi, Ineês Mota, Diego Alvarado, Elisa Landoni, Jasna Metovic, Manuel Nüesch, Rafael Blasco-Patiño, Mauro Papotti, Gianpietro Dotti, Roberto Chiarle. Generation of ALK CAR-T cells for neuroblastoma therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1544.