Abstract Melanoma and malignant pheochromocytoma are known for high MYC expression. MYCN amplification and its over-expression are associated with the worst neuroblastoma disease outcome. Meta-iodo-benzylguanidine (MIBG) is a norepinephrine analogue and a mitochondrial respiration inhibitor. 131I-MIBG has been used for scintigraphic detection of neural crest derived tumors (neuroblastoma, pheochromocytoma and melanoma) that specifically uptake MIBG by norepinephrine transporters (NET). 131I-MIBG is also used for targeted radiotherapy of neuroblastoma and pheochromocytoma. Non-radiolabeled MIBG had been reported to be cytotoxic to neuroblastoma cells in vitro and in vivo. However, the molecular mechanism of its growth suppressive effect was not elucidated. Our previous studies showed that FCCP, a well-known mitochondrial respiration inhibitor, destabilized MYCN and MYC in neuroblastoma cells and caused growth suppression. In this study we confirmed that MIBG suppressed growth of neuroblastoma cell lines (SKNBE(2)C, IMR5, Nb69, and SKNAS), and its growth suppressive effect in each cell line correlated with NET expression in these cells. In addition, MIBG suppressed growth of neuroblastoma stem cells derived from SKNBE(2)C. MIBG treatment of SKNBE(2)C and SKNAS resulted in an increase expression of growth suppressive gene (GADD45B) and genes encoding for biomarkers of favorable neuroblastoma (CD44, EPHB6, EFNB2, EFNB3, NTRK1). Treatment of MYCN amplified (SKNBE(2)C, IMR5) and non-MYCN amplified (Nb69, SKNAS) neuroblastoma cells with MIBG resulted in marked reduction of MYCN and MYC expression, respectively in dose and time dependent fashions. Collectively, our studies suggest that MIBG not only targets neural crest derived tumors, but also is a MYCN/MYC destabilizing agent. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2875. doi:1538-7445.AM2012-2875
<div>Abstract<p><i>MYCN</i> amplification strongly predicts adverse outcome of neuroblastoma. However, the significance of <i>MYCN</i> expression in the clinical and biological behavior of neuroblastoma has been unclear. To address this question, we first examined the expression of <i>MYCN</i> in combination with <i>TrkA</i> (a favorable prognostic indicator of neuroblastoma) in 91 primary neuroblastoma by quantitative reverse transcription-PCR and investigated the relationship among patient survival, <i>MYCN</i>, and <i>TrkA</i> expressions. Three subsets of neuroblastoma were defined based on <i>MYCN</i> and <i>TrkA</i> expression. Neuroblastoma expressing the highest level of <i>MYCN</i> but little <i>TrkA</i> were <i>MYCN</i>-amplified cases, which had a 5-year survival of 9.3%. Interestingly, <i>MYCN</i> and <i>TrkA</i> expression showed a linear correlation (<i>r</i> = 0.5664, <i>P</i> < 0.00005) in neuroblastoma lacking <i>MYCN</i> amplification, and the 5-year survival of neuroblastoma patients with low <i>MYCN</i> and low <i>TrkA</i> expressions was 63.7%, whereas those with high expression of both had a 5-year survival of 88.1% (<i>P</i> < 0.00005). This nonlinear distribution of disease outcome relative to <i>MYCN</i> expression in neuroblastoma explains why <i>MYCN</i> expression is not predictive of neuroblastoma disease outcome by dichotomous division of the neuroblastoma cohort. However, high-level <i>MYCN</i> expression is associated with favorable outcome in neuroblastoma lacking <i>MYCN</i> amplification. Furthermore, forced expression of MYCN significantly suppresses growth of neuroblastoma cells lacking <i>MYCN</i> amplification by inducing apoptosis and enhancing favorable neuroblastoma gene expression. Collectively, these data suggest that high-level <i>MYCN</i> expression in neuroblastoma lacking <i>MYCN</i> amplification results in a benign phenotype. Thus, the high <i>MYCN</i> expression confers the opposite biological consequence in neuroblastoma, depending on whether or not <i>MYCN</i> is amplified. (Cancer Res 2006; 66(5): 2826-33)</p></div>
<div>Abstract<p><i>MYCN</i> amplification strongly predicts adverse outcome of neuroblastoma. However, the significance of <i>MYCN</i> expression in the clinical and biological behavior of neuroblastoma has been unclear. To address this question, we first examined the expression of <i>MYCN</i> in combination with <i>TrkA</i> (a favorable prognostic indicator of neuroblastoma) in 91 primary neuroblastoma by quantitative reverse transcription-PCR and investigated the relationship among patient survival, <i>MYCN</i>, and <i>TrkA</i> expressions. Three subsets of neuroblastoma were defined based on <i>MYCN</i> and <i>TrkA</i> expression. Neuroblastoma expressing the highest level of <i>MYCN</i> but little <i>TrkA</i> were <i>MYCN</i>-amplified cases, which had a 5-year survival of 9.3%. Interestingly, <i>MYCN</i> and <i>TrkA</i> expression showed a linear correlation (<i>r</i> = 0.5664, <i>P</i> < 0.00005) in neuroblastoma lacking <i>MYCN</i> amplification, and the 5-year survival of neuroblastoma patients with low <i>MYCN</i> and low <i>TrkA</i> expressions was 63.7%, whereas those with high expression of both had a 5-year survival of 88.1% (<i>P</i> < 0.00005). This nonlinear distribution of disease outcome relative to <i>MYCN</i> expression in neuroblastoma explains why <i>MYCN</i> expression is not predictive of neuroblastoma disease outcome by dichotomous division of the neuroblastoma cohort. However, high-level <i>MYCN</i> expression is associated with favorable outcome in neuroblastoma lacking <i>MYCN</i> amplification. Furthermore, forced expression of MYCN significantly suppresses growth of neuroblastoma cells lacking <i>MYCN</i> amplification by inducing apoptosis and enhancing favorable neuroblastoma gene expression. Collectively, these data suggest that high-level <i>MYCN</i> expression in neuroblastoma lacking <i>MYCN</i> amplification results in a benign phenotype. Thus, the high <i>MYCN</i> expression confers the opposite biological consequence in neuroblastoma, depending on whether or not <i>MYCN</i> is amplified. (Cancer Res 2006; 66(5): 2826-33)</p></div>
Neuroblastoma is a pediatric cancer with significant clinical heterogeneity. Despite extensive efforts, it is still difficult to cure children with high-risk neuroblastoma. Immunotherapy is a promising approach to treat children with this devastating disease. We have previously reported that macrophages are important effector cells in high-risk neuroblastoma. In this perspective article, we discuss the potential function of the macrophage inhibitory receptor SIRPA in the homeostasis of tumor-associated macrophages in high-risk neuroblastoma. The ligand of SIRPA is CD47, known as a “don’t eat me” signal, which is highly expressed on cancer cells compared to normal cells. CD47 is expressed on both tumor and stroma cells, whereas SIRPA expression is restricted to macrophages in high-risk neuroblastoma tissues. Notably, high SIRPA expression is associated with better disease outcome. According to the current paradigm, the interaction between CD47 on tumor cells and SIRPA on macrophages leads to the inhibition of tumor phagocytosis. However, data from recent clinical trials have called into question the use of anti-CD47 antibodies for the treatment of adult and pediatric cancers. The restricted expression of SIRPA on macrophages in many tissues argues for targeting SIRPA on macrophages rather than CD47 in CD47/SIRPA blockade therapy. Based on the data available to date, we propose that disruption of the CD47-SIRPA interaction by anti-CD47 antibody would shift the macrophage polarization status from M1 to M2, which is inferred from the 1998 study by Timms et al. In contrast, the anti-SIRPA F(ab’)2 lacking Fc binds to SIRPA on the macrophage, mimics the CD47-SIRPA interaction, and thus maintains M1 polarization. Anti-SIRPA F(ab’)2 also prevents the binding of CD47 to SIRPA, thereby blocking the “don’t eat me” signal. The addition of tumor-opsonizing and macrophage-activating antibodies is expected to enhance active tumor phagocytosis.
Journal Article T cells from unprimed mice respond to the self antigen heme, in a class II restricted manner, at a frequency similar to alloresponses Get access Robyn M. Sutherland, Robyn M. Sutherland 1Department of Microbiology, University of PennsylvaniaPhiladelphia, PA 19104, USA3Present address: Department of Veterinary Pathology, University of SydneySydney, NSW 2006, Australia Search for other works by this author on: Oxford Academic PubMed Google Scholar Zhen-Kun Pan, Zhen-Kun Pan 1Department of Microbiology, University of PennsylvaniaPhiladelphia, PA 19104, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Andrew J. Caton, Andrew J. Caton 2Wistar Institute of Anatomy and BiologyPhiladelphia, PA 19104, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Xao X. Tang, Xao X. Tang 1Department of Microbiology, University of PennsylvaniaPhiladelphia, PA 19104, USA4Present address: Division of Neurology Research, Children's Hospital of PhiladelphiaPhiladelphia, PA 19104, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Douglas M. Cerasoli, Douglas M. Cerasoli 2Wistar Institute of Anatomy and BiologyPhiladelphia, PA 19104, USA Search for other works by this author on: Oxford Academic PubMed Google Scholar Yvonne Paterson Yvonne Paterson 1Department of Microbiology, University of PennsylvaniaPhiladelphia, PA 19104, USA Correspondence to: Y. Paterson Search for other works by this author on: Oxford Academic PubMed Google Scholar International Immunology, Volume 7, Issue 5, May 1995, Pages 771–783, https://doi.org/10.1093/intimm/7.5.771 Published: 01 May 1995 Article history Revision received: 19 September 1994 Accepted: 13 January 1995 Published: 01 May 1995
Abstract We previously showed that TSA (an HDAC inhibitor) and Epoxomycin (a proteasome inhibitor) as single agents and in combination significantly suppressed growth of MYCN-amplified neuroblastoma cells. However, these compounds had contrasting effects on MYCN expression. TSA down-regulated MYCN expression, but Epoxomycin and the TSA/Epoxomycin combination led to MYCN hyper-expression (defined as markedly increased expression beyond that observed in the untreated cells). The expression of p53 was also increased in MYCN-amplified cells treated with Epoxomycin or the TSA/Epoxomycin combination. In an independent study, we also found that treatment of neuroblastoma cells (MYCN-amplified or non-MYCN amplified) with 17-DMAG and S(+) Ibuprofen resulted in an increase in p53 expression and a reduction in MYCN or MYC expression. In this study, we examined (i) the pattern of gene expression induced by MYCN hyper-expression in MYCN-amplified cells, and (ii) a potential functional relationship between p53 and MYCN/MYC in neuroblastoma. Transient transfection of MYCN and TP53 into neuroblastoma cells was done by electroporation. Gene expression profiling, TaqMan real-time PCR, and Western blot assays were used to detect expression patterns of genes and proteins. It was observed that ectopic over MYCN expression in MYCN-amplified IMR5 cells resulted in growth suppression. Gene expression profiling analysis revealed that the hyper-expression of MYCN in the MYCN-transfected IMR5 cells led to an increased expression of genes involved in growth suppression and apoptosis, including EGR1, EPHA2, KLF2, PERP and SEL1L. The expression of PERP and EPHA2 was confirmed by TaqMan real-time PCR and Western blot assay, respectively. Interestingly, co-transfection of TP53 and MYCN in IMR5 cells led to high p53 expression but a reduction in MYCN expression (below the levels of endogenous MYCN). Transfection of TP53 into IMR5, SY5Y, and SKNAS reduced endogenous MYCN and MYC expression in these cells. Consistent with these observations, treatment of IMR5 and SY5Y cells with known p53-inducers, Doxorubicin and CoCl2, resulted in an increased p53 expression and a reduction of MYCN and MYC expression. Although high MYCN expression sustains growth of MYCN-amplified neuroblastoma, the hyper-expression of MYCN is deleterious to survival of these cells. In addition, augmented p53 expression may elicit a negative feedback regulation of MYCN/MYC expression in neuroblastoma. Citation Format: Naohiko Ikegaki, Xao Tang. A biological crosstalk between p53 and MYCN/MYC in neuroblastoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1218. doi:10.1158/1538-7445.AM2015-1218
