Neuroblastoma is the most common extracranial solid tumor of childhood. One important factor that predicts a favorable prognosis is the robust expression of the TRKA and p75NTR neurotrophin receptor ...genes. Interestingly, TRKA and p75NTR expression is often attenuated in aggressive MYCN-amplified tumors, suggesting a causal link between elevated MYCN activity and the transcriptional repression of TRKA and p75NTR, but the precise mechanisms involved are unclear. Here, we show that MYCN acts directly to repress TRKA and p75NTR gene transcription. Specifically, we found that MYCN levels were critical for repression and that MYCN targeted proximal/core promoter regions by forming a repression complex with transcription factors SP1 and MIZ1. When bound to the TRKA and p75NTR promoters, MYCN recruited the histone deacetylase HDAC1 to induce a repressed chromatin state. Forced re-expression of endogenous TRKA and p75NTR with exposure to the HDAC inhibitor TSA sensitized neuroblastoma cells to NGF-mediated apoptosis. By directly connecting MYCN to the repression of TRKA and p75NTR, our findings establish a key pathway of clinical pathogenicity and aggressiveness in neuroblastoma.
Fibromyalgia Syndrome (FMS) is characterized by chronic widespread pain, fatigue, unrefreshing sleep and cognitive dysfunction. Depressive and manic symptoms are often reported in FMS patients' ...history. The aim of this study was to evaluate the prevalence of bipolar spectrum symptoms (BSS) and to correlate these with quality of life (QoL) scores and antidepressant treatment.
From October 2017 to July 2018, a battery of QoL questionnaires (FIQ, PSQI and SF-12) was administered to 120 FMS patients after a clinical examination. The MOODS-SR lifetime questionnaire was then remotely administered to the patients included in the study.
The presence of depressive and manic lifetime symptoms was found, in line with the results of the available literature. A correlation was found between the history of depressive symptoms and the severity of FIQ and SF-12 scores. Despite a low statistical strength, a trend toward a correlation between a history of manic symptoms and SNRI treatment was detected.
The correlation between the MOOD-depressive domains and poor QoL is in line with the available literature. Further studies are needed to corroborate these findings and to elucidate the relationship between manic symptoms and SNRI treatment.
Genome amplification in the form of rings or giant rod-shaped marker chromosomes (RGMs) is a common genetic alteration in soft tissue tumors. The mitotic stability of these structures is often ...rescued by perfectly functioning analphoid neocentromeres, which therefore significantly contribute to cancer progression. Here, we disentangled the genomic architecture of many neocentromeres stabilizing marker chromosomes in well-differentiated liposarcoma and lung sarcomatoid carcinoma samples. In cells carrying heavily rearranged RGMs, these structures were assembled as patchworks of multiple short amplified sequences, disclosing an extremely high level of complexity and definitely ruling out the existence of regions prone to neocentromere seeding. Moreover, by studying two well-differentiated liposarcoma samples derived from the onset and the recurrence of the same tumor, we documented an expansion of the neocentromeric domain that occurred during tumor progression, which reflects a strong selective pressure acting toward the improvement of the neocentromeric functionality in cancer. In lung sarcomatoid carcinoma cells we documented, extensive "centromere sliding" phenomena giving rise to multiple, closely mapping neocentromeric epialleles on separate coexisting markers occur, likely due to the instability of neocentromeres arising in cancer cells. Finally, by investigating the transcriptional activity of neocentromeres, we came across a burst of chimeric transcripts, both by extremely complex genomic rearrangements, and
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-splicing events. Post-transcriptional editing events have been reported to expand and variegate the genetic repertoire of higher eukaryotes, so they might have a determining role in cancer. The increased incidence of fusion transcripts, might act as a driving force for the genomic amplification process, together with the increased transcription of oncogenes.
Childhood neuroblastoma, a disease of the sympathetic nervous system, is the most common solid tumour of infancy, remarkably refractory to therapeutic treatments. One of the most powerful independent ...prognostic indicators for this disease is the amplification of the MYCN oncogene, which occurs at high levels in approximately 25% of neuroblastomas. Interestingly, amplification and not just expression of MYCN has a strong prognostic value, although this fact appears quite surprising as MYCN is a transcription factor that requires dimerising with its partner MAX, to exert its function. This observation greatly suggests that the role of MYCN in neuroblastoma should be examined in the context of MAX expression.
In this report, we show that, in contrast to what is found in normal cells, MAX expression is significantly different among primary NBs, and that its level appears to correlate with the clinical outcome of the disease. Importantly, controlled modulation of MAX expression in neuroblastoma cells with different extents of MYCN amplification, demonstrates that MAX can instruct gene transcription programs that either reinforce or weaken the oncogenic process enacted by MYCN.
In general, our work illustrates that it is the MAX to MYCN ratio that can account for tumour progression and clinical outcome in neuroblastoma and proposes that such a ratio should be considered as an important criterion to the design and development of anti-MYCN therapies.
•MAX expression correlates with clinical outcome in neuroblastoma.•Modulation of MAX expression affects the oncogenic phenotype of neuroblastoma cells.•MAX silencing inhibits growth and motility of MYCN amplified neuroblastoma cells.•MAX silencing accelerates Retinoic Acid-mediated differentiation of MYCN-amplified neuroblastoma cells.•MAX to MYCN expression ratio may serve as an important criterion for the administration of anti-MYCN drugs.
Abstract
Myc oncoproteins exert tumorigenic effects by regulating the expression of target oncogenes. Histone H3 lysine 79 (H3K79) methylation at Myc-responsive elements of target gene promoters is a ...strict prerequisite for Myc-induced transcriptional activation. DOT1L is the only known histone methyltransferase that catalyses H3K79 methylation. Here, we showed that N-Myc up-regulated DOT1L mRNA and protein expression by binding to the DOT1L gene promoter. Knocking down DOT1L reduced mRNA and protein expression of the N-Myc target genes ODC1 and E2F2. DOT1L bound to the Myc Box II domain of N-Myc protein, and knocking down DOT1L reduced histone H3K79 methylation and N-Myc protein binding at the ODC1 and E2F2 gene promoters and reduced neuroblastoma cell proliferation. Treatment with the small molecule DOT1L inhibitor SGC0946 reduced H3K79 methylation and proliferation of MYCN gene-amplified neuroblastoma cells. In mice xenografted with neuroblastoma cells stably expressing doxycycline-inducible DOT1L small hair-pin RNA, ablating DOT1L expression with doxycycline significantly reduced ODC1 and E2F2 expression, reduced tumor progression and improved overall survival. In addition, high levels of DOT1L gene expression in human neuroblastoma tissues correlated with high levels of MYCN, ODC1 and E2F2 gene expression, and independently correlated with poor patient survival. Taken together, our data identify DOT1L as a novel co-factor in N-Myc-mediated transcriptional activation of target genes and neuroblastoma oncogenesis, and DOT1L inhibitors as novel anticancer agents against MYCN-amplified neuroblastoma.
Citation Format: Matthew Wong, Andrew Tee, Giorgio Milazzo, Jessica Bell, Stefan Hüttelmaier, Patsie Polly, Giovanni Perini, Christopher J. Scarlett, Tao Liu. The histone methyltransferase DOT1L promotes neuroblastoma by regulating gene transcription abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-080. doi:10.1158/1538-7445.AM2017-LB-080
MYCN is a major driver for the childhood cancer, neuroblastoma, however, there are no inhibitors of this target. Enhanced MYCN protein stability is a key component of MYCN oncogenesis and is ...maintained by multiple feedforward expression loops involving MYCN transactivation target genes. Here, we reveal the oncogenic role of a novel MYCN target and binding protein, proliferation-associated 2AG4 (PA2G4). Chromatin immunoprecipitation studies demonstrated that MYCN occupies the PA2G4 gene promoter, stimulating transcription. Direct binding of PA2G4 to MYCN protein blocked proteolysis of MYCN and enhanced colony formation in a MYCN-dependent manner. Using molecular modeling, surface plasmon resonance, and mutagenesis studies, we mapped the MYCN-PA2G4 interaction site to a 14 amino acid MYCN sequence and a surface crevice of PA2G4. Competitive chemical inhibition of the MYCN-PA2G4 protein-protein interface had potent inhibitory effects on neuroblastoma tumorigenesis
. Treated tumors showed reduced levels of both MYCN and PA2G4. Our findings demonstrate a critical role for PA2G4 as a cofactor in MYCN-driven neuroblastoma and highlight competitive inhibition of the PA2G4-MYCN protein binding as a novel therapeutic strategy in the disease. SIGNIFICANCE: Competitive chemical inhibition of the PA2G4-MYCN protein interface provides a basis for drug design of small molecules targeting MYC and MYCN-binding partners in malignancies driven by MYC family oncoproteins.
Purpose
Cancer mortality data allow assessing, at the same time, the risk of developing the disease and the quality of care provided to patients after the oncologic diagnosis. This study explores the ...risk of death caused by a single tumor site in a psychiatric population treated in a community-based psychiatric service.
Methods
All patients with an ICD-10 psychiatric diagnosis, seeking care in 1982–2006 (25 years), were included. Data were drawn from the South Verona Psychiatric Case Register (PCR). Mortality and cause of death were ascertained using different procedures and sources. Standardized mortality ratios (SMRs) were used to compare the observed number of deaths with the expected number using as reference a population in the Veneto region.
Results
Having been admitted to the hospital (SMR = 1.32), having a short interval from registration (1.52), having a diagnosis of alcoholism (2.03), and being a middle-aged male (1.83) were factors showing an increased risk of death from cancer. Increased SMRs were found for cancer of the oral cavity (22.93), lymphoma, leukemias, Hodgkin's lymphoma (8.01), and central nervous system (CNS) and cranial nerve tumors (4.75). The SMR decreased for stomach tumors (0.49). Patients with alcoholism (5.90 for larynx), affective disorders (20.00 for lymphomas), and personality disorders (28.00 for SNC) were found to be exposed to a high risk of cancer death in specific sites.
Conclusions
Psychiatric patients showed different patterns of site-specific cancer mortality when compared with the general population. The 20-fold higher risk of dying from hematological neoplasms needs further investigation. Chronic use of phenothiazines could be involved in the relative protection from stomach and prostate cancer found in psychiatric patients.
The centromere directs the segregation of chromosomes during mitosis and meiosis. It is a distinct genetic locus whose identity is established through epigenetic mechanisms that depend on the ...deposition of centromere-specific centromere protein A (CENP-A) nucleosomes. This important chromatin domain has so far escaped comprehensive molecular analysis due to its typical association with highly repetitive satellite DNA. In previous work, we discovered that the centromere of horse chromosome 11 is completely devoid of satellite DNA; this peculiar feature makes it a unique model to dissect the molecular architecture of mammalian centromeres. Here, we exploited this native satellite-free centromere to determine the precise localization of its functional domains in five individuals: We hybridized DNA purified from chromatin immunoprecipitated with an anti CENP-A antibody to a high resolution array (ChIP-on-chip) of the region containing the primary constriction of horse chromosome 11. Strikingly, each individual exhibited a different arrangement of CENP-A binding domains. We then analysed the organization of each domain using a single nucleotide polymorphism (SNP)-based approach and single molecule analysis on chromatin fibres. Examination of the ten instances of chromosome 11 in the five individuals revealed seven distinct ‘positional alleles’, each one extending for about 80–160 kb, were found across a region of about 500 kb. Our results demonstrate that CENP-A binding domains are autonomous relative to the underlying DNA sequence and are characterized by positional instability causing the sliding of centromere position. We propose that this dynamic behaviour may be common in mammalian centromeres and may determine the establishment of epigenetic alleles.
Mutations in the CDKL5 (cyclin-dependent kinase-like 5) gene are associated with a severe epileptic encephalopathy (early infantile epileptic encephalopathy type 2, EIEE2) characterized by ...early-onset intractable seizures, infantile spasms, severe developmental delay, intellectual disability, and Rett syndrome (RTT)-like features. Despite the clear involvement of CDKL5 mutations in intellectual disability, the function of this protein during brain development and the molecular mechanisms involved in its regulation are still unknown. Using human neuroblastoma cells as a model system we found that an increase in CDKL5 expression caused an arrest of the cell cycle in the G0/G1 phases and induced cellular differentiation. Interestingly, CDKL5 expression was inhibited by MYCN, a transcription factor that promotes cell proliferation during brain development and plays a relevant role in neuroblastoma biology. Through a combination of different and complementary molecular and cellular approaches we could show that MYCN acts as a direct repressor of the CDKL5 promoter. Overall our findings unveil a functional axis between MYCN and CDKL5 governing both neuron proliferation rate and differentiation. The fact that CDKL5 is involved in the control of both neuron proliferation and differentiation may help understand the early appearance of neurological symptoms in patients with mutations in CDKL5.
► CDKL5 enhances neuronal differentiation. ► CDKL5 arrests cell cycle of neuronal precursor cells. ► MYCN directly represses transcription of CDKL5. ► These results may help explain the neurological symptoms of RTT patients.
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