Myxoid glioneuronal tumor: Histopathologic, neuroradiologic, and molecular features in a single center series

BACKGROUND

Myxoid glioneuronal tumor (MGT) is a benign glioneuronal neoplasm recently introduced in the World Health Organization (WHO) classification of the central nervous system (CNS) tumors. MGTs are typically located in the septum pellucidum, foramen of Monro or periventricular white matter of the lateral ventricle. They were previously diagnosed as dysembryoplastic neuroepithelial tumors (DNT), showing histological features almost indistinguishable from classical cortical DNT. Despite that, MGTs have been associated with a specific dinucleotide substitution at codon 385 in the platelet-derived growth factor receptor alpha (PDGFRA) gene, replacing a lysine residue with either leucine or isoleucine (p. LysK385Leu/Iso). This genetic variation has never been described in any other CNS tumor.

MATERIALS AND METHODS

Thirty-one consecutive tumors, previously diagnosed as DNTs at the Meyer Children's Hospital IRCCS between January 2010 and June 2021 were collected for a comprehensive study of their clinical, imaging, pathological features, and molecular profile.

RESULTS

In six out of the thirty-one tumors we had previously diagnosed as DNTs, we identified the recurrent dinucleotide mutation in the PDGFRA. All six tumors were typically located within the periventricular white matter of the lateral ventricle and in the septum pellucidum. We then renamed these lesions as MGT, according to the latest WHO CNS classification. In all patients we observed an indolent clinical course, without recurrence.

CONCLUSION

MGT represent a rare but distinct group of neoplasm with a typical molecular profiling, a characteristic localization, and a relative indolent clinical course.

P17.13.A Verteporfin inhibits autophagy in glioblastoma cell lines

Background

Glioblastoma (GBM) is the most common primary brain tumor with a poor prognosis, characterized by a high cellular heterogeneity and invasiveness. Multi-drug resistance (MDR), the blood brain barrier (BEE) and DNA repair systems let the survival of tumor cells, making the treatment with chemo and radiotherapy not effective. Autophagy is a physiological mechanism that allows the recycling of damaged proteins and organelles, in order to protect the correct cell turnover. However, in GBM this process promotes survival and proliferation in stressful conditions such as after a chemo and / or radiotherapy treatment. The Hippo pathway is an extremely important molecular signaling because it is involved in various tumorigenesis processes, for instance the epithelium-mesenchymal transition (EMT), in the increase of stemness, mechanotransduction and chemoresistance.

Material and Methods

The modulation of autophagy was evaluated in GBM cell lines (U87MG, T98G and A172) exploiting a fluorescent detection that allowed the quantification of the autophagosomal activity present into the cell lines. The rate of autophagy was assessed after the cell lines pharmacological treatment with Hippo pathway inhibitors, Verteporfin 2uM (VP) for 24h, Latrunculin 0,5uM (LAT) for 3h and Cytochalasin 1uM (CIT) for 3h, with Doxorubicin 0,5uM (DOX) for 24h and with the drugs combination (DOX-VP, DOX-LAT and DOX-CIT). Moreover, the expression of the autophagy marker LC3II / I was evaluated in all three GBM cell lines by Western Blotting (WB) experiments. To perform this technique, the cells were treated with DOX and Hippo pathway inhibitors respecting the pharmacological treatment previously used. Then, the proteins were extracted, quantified and finally the WB was performed.

Results

The results obtained showed that the three GBM cell lines without any drugs were marked by high levels of autophagy, similar to the cells treated with Rapamycin, an autophagy inducer. Moreover, the autophagy rate was definitely reduced after treatment with VP and DOX-VP in all three cell lines, including the chemoresistant T98G. Conversely, the other two Hippo pathway inhibitors (LAT-CIT) and DOX did not significantly change the rate of autophagy. The expression of LC3II / I was particularly low after treatment with VP and DOX-VP in all three cell lines while the other two inhibitors did not significantly change its expression.

Conclusion

In conclusion, these data demonstrated that the three GBM cell lines (U87MG, T98G and A172) are characterized by high levels of autophagy and the inhibition of the Hippo pathway with VP and especially the combination DOX-VP reduced the activation of this protumoral molecular mechanism in GBM cell lines.

Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi

Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star's wind can accelerate particles. We report very-high-energy (VHE, [Formula: see text]) gamma rays from the recurrent nova RS Ophiuchi, up to a month after its 2021 outburst, observed using the High Energy Stereoscopic System. The VHE emission has a similar temporal profile to lower-energy GeV emission, indicating a common origin, with a two-day delay in peak flux. These observations constrain models of time-dependent particle energization, favoring a hadronic emission scenario over the leptonic alternative. Shocks in dense winds provide favorable environments for efficient acceleration of cosmic-rays to very high energies.

P06.07 Germline mutation of SMARCE1 gene in a family with spinal meningiomas

BACKGROUND

Meningioma is the most common benign primary intracranial tumor, arising from arachnoid cells of the meninges, but in 20% of cases displays aggressive behavior. Meningiomas are mainly sporadic and the familial forms are very rare. Meningioma account for a small subset (1–4%) of all pediatric brain tumors and may be associated with hereditary tumor predisposition syndrome caused by germline mutations of NF2, SMARCB1, SUFU, and SMARCE1 genes.

MATERIAL AND METHODS

We present a case of a 16-year-old girl with spinal clear cell meningiomas (CCMs) WHO II with a second spinal lesion identified during the follow-up. Considering the multiple lesions, we performed Whole Exome Sequencing (WES) on DNA from peripheral blood to search for an underlying CCMs tumor predisposition syndrome (#607174).

RESULTS

We identified a heterozygous frameshift variant c.439delA (p.Ser147fs) in SMARCE1, chromatin remodelling factor that acts as a tumor suppressor gene. Meningioma analysis by Sanger sequencing showed a loss of heterozygosity (LOH) of the wild-type allele. We identified the c.439delA in the constitutional DNA of the father and the sister but not in the mother. At the moment, the father is asymptomatic and the 14 years old sister showed two spinal lesions (meningiomas likely) at the first MRI.

CONCLUSION

We report a family study of hereditary tumor predisposition syndrome to CCMs with SMARCE1 mutation in which are present two asymptomatic carriers with different ages and gender. The asymptomatic carriers will undergo neurological examination and MRI of the brain and spine, according to a screening protocol. The incomplete penetrance phenomenon is known in SMARCE1-related families with CCMs and it is probably due to the interaction of SMARCE1 with yet unidentified genes.

P04.20 The role of YAP in Glioblastoma cell lines

BACKGROUND

Glioblastoma (GBM) is a primary human malignant brain tumor, the most common in adults. Several studies have highlighted the Hippo-pathway as a cancer signalling network. The Hippo pathway is an evolutionarily conserved signal cascade, which is involved in the control of organ growth. Dysregulations among this pathway have been found in lung, ovarian, liver and colorectal cancer. The key downstream effector of the Hippo-pathway is the Yes-associated protein (YAP); in the nucleus, its function as transcription co-activator is to interact with transcription factors, resulting in the expression of target genes involved in pro-proliferating and anti-apoptotic programs.

MATERIAL AND METHODS

Using western blotting analysis, we determined the nuclear expression of YAP on three GBM cell lines (U87MG, T98G and A172). To investigate which inhibitors against the Hippo-pathway were the most efficient, we performed a cytotoxic assay: we treated all the three cell lines with different inhibitors such as Verteporfin (VP), Cytochalasin D (CIT), Latrunculin A (LAT), Dobutamine (DOB) and Y27632. Afterwards, we performed a treatment using Doxorubicin (DOX) combined with the inhibitors, evaluating its cytotoxic effect on our cell lines, through cell viability experiments. More western blotting experiments were performed to investigate the oncogenic role of YAP at nucleus level. Furthermore, preliminary experiments have been conducted in order to investigate the apoptosis, senescence and autophagy modulation due to the Hippo-pathway.

RESULTS

We showed our cell lines express nuclear YAP. We assessed the efficiency of the main inhibitors against Hippo-pathway, proving that VP, LAT A and CIT show a strong cytostatic effect, linked to time increase; plus we saw a cytotoxic effect on T98G. The association of DOX with selected inhibitors is able to reduce cell viability and nuclear YAP expression rate in all three GBM lines. Finally, preliminary experiments were set up to assess how and if the mechanisms of apoptosis, autophagy and senescence were affected by the Hippo-pathway. The combination of DOX with inhibitors promotes resistance to apoptosis.

CONCLUSION

Our results show that nuclear YAP is present in all tumor lines, thus confirming that this molecular pathway is functioning in GBM lines. Nuclear YAP is more highly expressed after DOX administration. Moreover, the combined treatment (DOX with Hippo-pathway inhibitors) reduces both cell proliferation and viability, and increases the rate of apoptosis. Preliminary experiments on senescence and autophagy were used to determine the best Hippo-pathway inhibitor. These data demonstrate that the Hippo-pathway plays a crucial role in GBM proliferation and resistance to apoptosis. Inhibiting this pathway and in particular the transcription factor YAP, in association with DOX, might be an excellent therapeutic target.

Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow

Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera-electron volts, this spectrum is described by a power law with photon index of 2.07 ± 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.

P04.08 The role of SCN1A in glioblastomas and mixed neuronal glial tumors of pediatric age

BACKGROUND

Low and high grade gliomas, are the most common pediatric central nervous system (CNS) tumors and they show an extremely broad range of clinical behavior. Pediatric glioma is distinct from its adult counterpart with different genetic/epigenetic profile and biological features. Recently, several studies have shown the involvement of voltage-gated Na+ channels (VGSC) in different types of cancer, including gliomas. VGSC are multimeric transmembrane complexes, responsible for membrane depolarization in excitable cells playing an important role also in cell proliferation, migration, apoptosis and differentiation. VGSC are therapeutic targets in cardiovascular and neurological disorders and, in cancers, they could be a novel target for the development of promising anticancer therapy

MATERIAL AND METHODS

Firstly, we explored the genetic background of 9 pediatric glioblastomas (1–9 pGBMs), through whole-exome sequencing (WES) using HiSeq1000 platform (Illumina) with paired-end approach. On the basis of our results, we extended our study in another group of 16 epileptogenic mixed neuronal-glial tumors of pediatric age, (WHO grade I and II), through an amplicon approach (TSCA) using MiniSeq System platform (Illumina)

RESULTS

We identified variants in SCN1A gene in 3/9 pGBMs: case 3 had c.5782C>G in tumor and blood; case 5 showed c.2278G>T and two mosaic variants (c.5933C>T, 22% and c.4942C>T, 14%); case 6 showed c.667G>T variant only in tumor, and not in other non tumoral tissues (blood, urine and buccal swab). No variants in SCN1A were identified in a group of 16 pediatric mixed gliomas

CONCLUSION

In this study, we explore the genetic background of two groups of pediatric neuroepithelial brain tumors, through Next generation sequencing approach. We identified only in pGBMs variants in SCN1A gene that encoded for VGSCs and is involved in a spectrum of early-onset epileptic encephalopathies. None of our mutated patients showed history of epilepsy. Now, it is not clear the significance of these variants in pGBMs but interestingly, these variants are present in pGBM and not in mixed gliomas. Further studies on a big cohort of patients are needed to establish if they could play a role in pGBMs aggressiveness, migration and progression. Moreover, VGSCs could be a pharmacological target in pGBMs treatment

Morquio A syndrome due to maternal uniparental isodisomy of the telomeric end of chromosome 16

Morquio A syndrome (MPS IVA) is a recessive lysosomal storage disorder (LSD) caused by mutations in the GALNS gene leading to the deficiency of lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Patients show a broad spectrum of phenotypes ranging from classical severe type to mild forms. Classical forms are characterized by severe bone dysplasia and usually normal intelligence. So far, more than 170 unique mutations have been identified in the GALNS gene of MPS IVA patients. We report on a Morquio A patient with a classical phenotype who was found to be homozygous for a missense mutation (c.236 G>A; p.Cys79Tyr) in the GALNS gene. This alteration affects the highly conserved p.Cys79 that is transformed into formylglycine, the catalytic residue of the active site. The mutation was present in the proband's mother, but not in the father, whose paternity was confirmed by microsatellite analysis. In order to test the hypothesis of maternal uniparental disomy (UPD), we investigated the segregation of sixteen microsatellite markers from chromosome 16. The results showed a condition of maternal UPD due to an error in meiosis I. Maternal isodisomy of the 16q24 region led to homozygosity for the GALNS mutant allele, causing the patient's disease. These findings allow to add for the first time the LSD Morquio A syndrome to the list of conditions that can be caused by UPD. The possibility of UPD is relevant when giving genetic counseling to couples since the recurrent risk in future pregnancies is dramatically reduced.

Subtyping mtDNA haplogroup H by SNaPshot minisequencing and its application in forensic individual identification

Sequence variation of the hypervariable segments (HVS) I/II of mitochondrial DNA (mtDNA) and the haplogroup affiliation were determined in a sample of 271 Italian subjects. This analysis showed that 42% of the individuals could be ascribed to H, the most frequent haplogroup in European Caucasian populations. This fraction was then screened for specific single nucleotide polymorphisms located in the coding region to identify H subclades H1-H15. We set up two multiplex polymerase chain reactions and specific SNaPshot assays to investigate the frequency distribution of these subgroups in our population sample and to examine their usefulness in discriminating among commonly shared HVS I/II sequences. This allowed the assignment of a large portion of the mtDNAs ( approximately 70%) to specific subhaplogroups, with H1 and H5 being the most represented. About two-thirds of the individuals sharing common HVS I/II sequences were subdivided and ascribed to specific H subhaplogroups with a significant reduction of the frequencies of the most common mtDNA haplotypes. Haplogroup H subtyping could thus be extremely useful in forensic identification when many samples have to be analysed and compared, avoiding excessive time-consuming and labor-intensive sequencing analysis.

[Epigenetic study of Rett's syndrome as an adequate model for autistic disorders]

Rett's syndrome (RTT) is a severe hereditary disorder of the nervous system. MECP2 gene mutations are considered as a primary cause of the disease. In the present study, we have found MECP2 mutations in 33 (84.6%) out of 39 RTT females. We have also studied X-inactivation patterns in 70 girls with RTT. A frequency of skewed X-inactivation was 37% (26 patients), being significantly higher (p < 0.001) than that in the controls. The investigation of inactivated X chromosome origin revealed that about 33% pairs had preferentially the inactivated maternal X chromosome. An abnormal type of chromosome X inactivation was observed in all RTT females. Thus, we conclude that skewed X-inactivation may be considered as a common feature of RTT. There is unambiguous evidence that epigenetic alterations in RTT are associated with MECP2 mutations. MeCP2 protein also appears to be involved in transcriptional regulation of chromosome X genes. RTT in females without MECP2 mutations is related to the epigenetic alterations. We suggest X chromosome inactivation study in RTT females and their mothers to be informative for investigation of genetic processes in RTT girls, even in case MECP2 mutations have not been found. RTT could be considered as an appropriate model for studying epigenetic abnormalities in relation to autistic spectrum disorders.

Fuzzy predictive control for nitrogen removal in biological wastewater treatment

Whenever the carbon/nitrogen ratio of a domestic wastewater is too low, full denitrification is difficult to obtain and an additional source of organic carbon has to be provided. Since loading conditions may vary appreciably over the diurnal cycle, depending on the weather and sewage conditions, dosing should be controlled by an adaptive regulator to keep into account the time-varying process dynamics. A fuzzy predictive controller is proposed in this paper and its performance is tested through numerical simulations. The new aspects brought forward are the use of an improved model for denitrification, the use of benchmark (i.e. thoroughly tested and standardised) input files and the conclusion about regulator performance in overall plant performance, in terms of carbon saving and discharge compliance.

Spectrum and distribution of MECP2 mutations in 64 Italian Rett syndrome girls: tentative genotype/phenotype correlation

We report a direct DNA sequencing analysis of the MECP2 gene undertaken on a further 64 Italian patients with Rett syndrome by using a LICOR 4200 Automated Sequencer. All of the girls entering the study had a consistent clinical diagnosis for this disorder. All coding regions and the flanking intronic splice site sequences were amplified as three non-overlapping fragments by using both forward and reverse primers. The results were then compared to the MECP2 reference sequences published in GenBank. Mutations of the MECP2 gene were identified in 64 of 75 (85.33%) unrelated sporadic Rett syndrome girls. Genotype/phenotype correlation studies, in particular in groups of patients with the same mutation, did not offer definitive and interesting data.

Infrared fluorescent automated detection of thirteen short tandem repeat polymorphisms and one gender-determining system of the CODIS core system

We used an infrared (IR) automated fluorescence monolaser sequencer for the analysis of 13 autosomal short tandem repeat (STR) systems (TPOX, D3S1358, FGA, CSF1PO, D5S818, D7S820, D8S1179, TH01, vWA, D13S317, D16S359, D18S51, D21S11) and the X-Y homologous gene amelogenin system. These two systems represent the core of the combined DNA index systems (CODIS). Four independent multiplex reactions, based on the polymerase chain reaction (PCR) technique and on the direct labeling of the forward primer of every primer pair, with a new molecule (IRDye800), were set up, permitting the exact characterization of the alleles by comparison with ladders of specific sequenced alleles. This is the first report of the whole analysis of the STRs of the CODIS core using an IR automated DNA sequencer. The protocol was used to solve paternity/maternity tests and for population studies. The electrophoretic system also proved useful for the correct typing of those loci differing in size by only 2 bp. A sensibility study demonstrated that the test can detect an average of 10 pg of undegraded human DNA. We also performed a preliminary study analyzing some forensic samples and mixed stains, which suggested the usefulness of using this analytical system for human identification as well as for forensic purposes.

Direct sequencing of long polymerase chain reaction fragments

Direct sequencing of polymerase chain reaction (PCR)-generated templates is a commonly used technique in molecular biology laboratories. We describe an improved method for direct sequencing of PCR fragments longer than 20 kb obtained with a commercial mixture of Taq and Pwo DNA polymerases. The sequencing protocol was optimized for an automated infrared DNA sequencer, consistently yielding long reads (500-600 bases).

Temporary prosthesis for laryngotracheal stenosis: a clinical report

Clinical and laboratory procedures to fabricate a transitional prosthesis for patients treated with laryngofissure surgery have been described. Hard resin promoted healing of the surgical area and maintained the opening because of its stiffness. The prosthesis, which can be highly polished, was easily removed by the patient for proper hygiene and was fabricated to accurately fit the inside margins of the wound. All these factors were important for a good clinical result.