Medulloblastoma (MB) is a malignant pediatric brain tumor arising in the cerebellum consisting of four distinct subgroups: WNT, SHH, Group 3 and Group 4, which exhibit different molecular phenotypes. We studied the expression of Dickkopf (DKK) 1-4 family genes, inhibitors of the Wnt signaling cascade, in MB by screening 355 expression profiles derived from four independent datasets. Upregulation of DKK1, DKK2 and DKK4 mRNA was observed in the WNT subgroup, whereas DKK3 was downregulated in 80% MBs across subgroups with respect to the normal cerebellum (p < 0.001). Since copy number aberrations targeting the DKK3 locus (11p15.3) are rare events, we hypothesized that epigenetic factors could play a role in DKK3 regulation. Accordingly, we studied 77 miRNAs predicting to repress DKK3; however, no significant inverse correlation between miRNA/mRNA expression was observed. Moreover, the low methylation levels in the DKK3 promoters (median: 3%, 5% and 5% for promoter 1, 2 and 3, respectively) excluded the downregulation of gene expression by methylation. On the other hand, the treatment of MB cells with Trichostatin A (TSA), a potent inhibitor of histone deacetylases (HDAC), was able to restore both DKK3 mRNA and protein. In conclusion, DKK3 downregulation across all MB subgroups may be due to epigenetic mechanisms, in particular, through chromatin condensation.
At diagnosis, children with neuroblastoma (NB) present with either localized or metastatic disease. Since the mechanisms responsible for BM invasion are not well known, we investigated the transcriptome of resident BM cells from NB patients as compared to healthy children.
Transthoracic echocardiography (TTE) has been traditionally considered inadequate for the diagnosis of acute type A aortic syndrome (AAAS). In the last decade, high-resolution probes and harmonic imaging have been implemented in new echocardiographic systems. However, studies assessing the diagnostic accuracy of TTE for the identification of AAAS in large populations using modern ultrasound technology are lacking.
Neural Crest Cells (NCCs) are transient multipotent migratory cells that derive from the embryonic neural crest which is itself derived from the margin of the neural tube. DNA repair genes are expressed in the early stages of mammalian development to reduce possible replication errors and genotoxic damage. Some birth defects and cancers are due to inappropriate or defective DNA repair machinery, indicating that the proper functioning of DNA repair genes in the early stages of fetal development is essential for maintaining DNA integrity. We performed a genome-wide expression analysis combining laser capture microdissection (LCM) and high-density oligo-microarray of murine NCCs at pre-migratory embryonic days 8.5 (E8.5), and at E13.5, as well as on neural crest-derived cells from the adrenal medulla at postnatal day 90. We found 11 genes involved in DNA repair activity (response to DNA damage stimulus, DNA damage checkpoint, base-excision repair, mismatch repair), over-expressed in the early stages of mouse embryo development. Expression of these 11 genes was very low or undetectable in the differentiated adrenal medulla of the adult mouse. Amongst the 11 genes, 6 had not been previously reported as being over-expressed during mouse embryonic development. High expression of DNA repair genes in enriched NCCs during early embryonic development may contribute to maintaining DNA integrity whilst failure of some of these genes may be associated with the onset of genetic disease and cancer. Our model of enriched murine NCCs and neural crest-derived cells can be used to elucidate the key roles of genes during normal embryonic development and in cancer pathogenesis.
The present study evaluates the effects of combined leflunomide (LEF) and low dose of prednisone therapy, on selected inflammatory gene expression in peripheral blood mononuclear cells (PBMCs) of early rheumatoid arthritis (ERA) patients by gene microarray analysis and quantitative real time-polymerase chain reaction (qRT-PCR).
The interpretation of gene interaction in biological networks generates the need for a meaningful ranking of network elements. Classical centrality analysis ranks network elements according to their importance but may fail to reflect the power of each gene in interaction with the others.
The effects of low dose prednisone (PD) alone or in combination with leflunomide (LEF) were tested on inflammatory gene expression in early rheumatoid arthritis (RA). Ten RA patients were assigned as group A (untreated)and group B (pretreated with PD 5 mg/day for 3 months -T0). Therefore, both groups were treated with LFN (20mg/day). Expression ratio of 34 inflammatory genes was detected by microarray analysis in early RA patients and CNT (5), before (T0), and after 3 months (T1) of combined therapy (PN+LFN). At T0, 17 genes linked with arthritis were found altered in early RA, (A and B groups), compared to CNT. At T1 in the group A, 41% of genes were found unchanged, 12% upregulated, and 47% downregulated, whereas in the group B, 65% of genes were found unchanged, 6% upregulated, and 29% downregulated. The results suggest that the combination of PN and LEF seems to play a synergistic effect by modulating some inflammatory genes in early RA.
Neuroblastoma is the most common, pediatric, extra-cranial, malignant solid tumor. Despite multimodal therapeutic protocols, outcome for children with a high-risk clinical phenotype remains poor, with long-term survival still less than 40%. Hereby, we evaluated the potential of non-coding RNA expression to predict outcome in high-risk, stage 4 neuroblastoma.
We aimed to identify novel molecular prognostic markers to better predict relapse risk estimate for children with high-risk (HR) metastatic neuroblastoma (NB). We performed genome- and/or transcriptome-wide analyses of 129 stage 4 HR NBs. Children older than 1 year of age were categorized as "short survivors" (dead of disease within 5 years from diagnosis) and "long survivors" (alive with an overall survival time ? 5 years). We reported that patients with less than three segmental copy number aberrations in their tumor represent a molecularly defined subgroup with a high survival probability within the current HR group of patients. The complex genomic pattern is a prognostic marker independent of NB-associated chromosomal aberrations, i.e., MYCN amplification, 1p and 11q losses, and 17q gain. Integrative analysis of genomic and expression signatures demonstrated that fatal outcome is mainly associated with loss of cell cycle control and deregulation of Rho guanosine triphosphates (GTPases) functioning in neuritogenesis. Tumors with MYCN amplification show a lower chromosome instability compared to MYCN single-copy NBs (P = .0008), dominated by 17q gain and 1p loss. Moreover, our results suggest that the MYCN amplification mainly drives disruption of neuronal differentiation and reduction of cell adhesion process involved in tumor invasion and metastasis. Further validation studies are warranted to establish this as a risk stratification for patients.
Metastases in the bone marrow (BM) are grim prognostic factors in patients with neuroblastoma (NB). In spite of extensive analysis of primary tumor cells from high- and low-risk NB patients, a characterization of freshly isolated BM-infiltrating metastatic NB cells is still lacking. Our aim was to identify proteins specifically expressed by metastatic NB cells, that may be relevant for prognostic and therapeutic purposes. Sixty-six Italian children over 18 months of age, diagnosed with stage 4 NB, were included in the study. Metastatic NB cells were freshly isolated from patients BM by positive immunomagnetic bead manipulation using anti-GD2 monoclonal antibody. Gene expression profiles were compared with those obtained from archived NB primary tumors from patients with 5 y-follow-up. After validation by RT-qPCR, expression/secretion of the proteins encoded by the up-regulated genes in the BM-infiltrating NB cells was evaluated by flow cytometry and ELISA. Compared to primary tumor cells, BM-infiltrating NB cells down-modulated the expression of CX3CL1, AGT, ATP1A2 mRNAs, whereas they up-regulated several genes commonly expressed by various lineages of BM resident cells. BM-infiltrating NB cells expressed indeed the proteins encoded by the top-ranked genes, S100A8 and A9 (calprotectin), CD177 and CD3, and secreted the CXCL7 chemokine. BM-infiltrating NB cells also expressed CD271 and HLA-G. We have identified proteins specifically expressed by BM-infiltrating NB cells. Among them, calprotectin, a potent inflammatory protein, and HLA-G, endowed with tolerogenic properties facilitating tumor escape from host immune response, may represent novel biomarkers and/or targets for therapeutic intervention in high-risk NB patients.
About 50% of children with neuroblastoma (NB) show a metastatic disease and have a poor prognosis. However, disease progression is greatly variable and depends on patients age and MYCN oncogene amplification. To investigate the role of patients age in tumor aggressiveness, we performed array-CGH and gene expression profiles of three groups (G) of metastatic NBs: G1, stage 4S patients and MYCN single copy (MYCN-) tumors; G2, stage 4 patients, ? 18 months of age, MYCN- tumors and favorable outcome and G3, Stage 4 patients, ? 19 months with unfavorable outcome. G1 was characterized by numerical aberrations prevalently; on the contrary, all G3 tumors had structural rearrangements, whereas G2 showed an intermediate pattern. The average of numerical alterations decreased significantly from G1 to G2 to G3 (p < 0.01). Contrarily, the number of structural aberrations increased from G1 to G2 to G3 (p < 2.35 E-05). Noteworthy, G3/MYCN- NBs were characterized by several complex intrachromosome rearrangements. Expression analysis of the three groups showed significant differences in genes of Rho and Ras signaling pathways, development and adhesion, cell cycle regulation and telomerase activity. Accumulation of structural alterations increased with patients age and was associated with a more aggressive disease. Abnormal expression of genes involved in cell cycle and telomerase in G3 may be responsible for the genomic instability in this cohort of patients. The higher DNA instability observed in G3/MYCN- NBs than in MYCN-amplified G3 may also explain why patients ? 19 months have a poor outcome independently by MYCN status.
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