Human brain astrocytomas range from the indolent low-grade to the highly infiltrating and aggressive high-grade form, also known as glioblastoma multiforme. The extensive heterogeneity of astrocytic tumors complicates their pathological classification. In this study, we compared the protein pattern of low-grade fibrillary astrocytomas to that of glioblastoma multiforme by 2D electrophoresis. The level of most proteins remains unchanged between the different grade tumors and only few differences are reproducibly observable. Fifteen differentially expressed proteins, as well as seventy conserved spots, were identified by mass spectrometry. Western and immnunohistochemical analysis confirmed the differential expression of the identified proteins. These data provide an initial reference map for brain gliomas. Among the proteins more highly expressed in glioblastoma multiforme, we found peroxiredoxin 1 and 6, the transcription factor BTF3, and alpha-B-crystallin, whereas protein disulfide isomerase A3, the catalytic subunit of the cAMP-dependent protein kinase, and the glial fibrillary acidic protein are increased in low-grade astrocytomas. Our findings contribute to deepening our knowledge of the factors that characterize this class of tumors and, at the same time, can be applied toward the development of novel molecular biomakers potentially useful for an accurate classification of the grade of astrocytomas.

Background: Translational medicine aims at transferring advances in basic science research into new approaches for diagnosis and treatment of diseases. Low-grade gliomas (LGG) have a heterogeneous clinical behavior that can be only partially predicted employing current state-of-theart markers, hindering the decision-making process. To deepen our comprehension on tumor heterogeneity, we dissected the mechanism of interaction between tumor cells and relevant components of the neoplastic environment, isolating, from LGG and high-grade gliomas (HGG), proliferating stem cell lines from both the glioma stroma and, where possible, the neoplasm. Methods and Findings: We isolated glioma-associated stem cells (GASC) from LGG (n540) and HGG (n573). GASC showed stem cell features, anchorage-independent growth, and supported the malignant properties of both A172 cells and human glioma-stem cells, mainly through the release of exosomes. Finally, starting from GASC obtained from HGG (n513) and LGG (n512) we defined a score, based on the expression of 9 GASC surface markers, whose prognostic value was assayed on 40 subsequent LGG-patients. At the multivariate Cox analysis, the GASCbased score was the only independent predictor of overall survival and malignant progression free-survival. Conclusions: The microenvironment of both LGG and HGG hosts non-tumorigenic multipotent stem cells that can increase in vitro the biological aggressiveness of gliomainitiating cells through the release of exosomes. The clinical importance of this finding is supported by the strong prognostic value associated with the characteristics of GASC. This patientbased approach can provide a groundbreaking method to predict prognosis and to exploit novel strategies that target the tumor stroma.

BackgroundRecQ helicases play an essential role in the maintenance of genome stability. In humans, loss of RecQ helicase function is linked with predisposition to cancer and/or premature ageing. Current data show that the specific depletion of the human RECQ1 helicase leads to mitotic catastrophe in cancer cells and inhibition of tumor growth in mice.ResultsHere, we show that RECQ1 is highly expressed in various types of solid tumors. However, only in the case of brain gliomas, the high expression of RECQ1 in glioblastoma tissues is paralleled by a lower expression in the control samples due to the poor expression of RECQ1 in non-dividing tissues. This conclusion is validated by immunohistochemical analysis of a tissue microarray containing 63 primary glioblastomas and 19 perilesional tissue samples, as control. We also show that acute depletion of RECQ1 by RNAi results in a significant reduction of cellular proliferation, perturbation of S-phase progression, and spontaneous γ-H2AX foci formation in T98G and U-87 glioblastoma cells. Moreover, RECQ1 depleted T98G and U-87 cells are hypersensitive to HU or temozolomide treatment.ConclusionsCollectively, these results indicate that RECQ1 has a unique and important role in the maintenance of genome integrity. Our results also suggest that RECQ1 might represent a new suitable target for anti cancer therapies aimed to arrest cell proliferation in brain gliomas.

OBJECTIVEIn the last 2 decades, the endoscopic endonasal approach in the treatment of clival chordomas has evolved to be a viable strategy to achieve maximal safe resection of this tumor. Here, the authors present a multicentric national study, intending to analyze the evolution of this approach over a 20-year time frame and its contribution in the treatment of clival chordomas.METHODSClival chordoma cases surgically treated between 1999 and 2018 at 10 Italian neurosurgical departments were included in this retrospective study. Clinical, radiological, and surgical findings, adjuvant therapy, and outcomes were evaluated and compared according to classification in the treatment eras from 1999 to 2008 and from 2009 to 2018.RESULTSOne hundred eighty-two surgical procedures were reviewed, with an increase in case load since 2009. The endoscopic endonasal transclival approach (EETA) was performed in 151 of 182 cases (83.0%) and other approaches were performed in 31 cases (17%). There was an increment in the use of EETA, neuronavigation, and Doppler ultrasound after 2008. The overall postoperative complication rate was 14.3% (26 of 182 cases) consisting of 9 CSF leaks (4.9%), 7 intracranial hemorrhages (3.8%), 5 cases of meningitis (2.7%), and 5 cerebral ischemic injuries (2.7%). Gross-total resection (GTR) was achieved in 93 of 182 cases (51.1%). Extent of resection (EOR) improved in the second era of the study. Signs and/or symptoms at presentation worsened in 27 cases (14.8%), and the Katz Index worsened in 10 cases (5.5%). Previous treatment, dural involvement, EETA, and intraoperative Doppler ultrasound correlated with GTR. Patients received adjuvant proton beam radiation in 115 of 182 cases (63.2%), which was administered more in the latter era. Five-year progression-free survival (PFS) and overall survival (OS) were 62.3% and 73.5%, respectively. GTR, EETA, proton beam therapy, and the chondroid subtype correlated with a better survival rate. The mean follow-up was 62 months.CONCLUSIONSThrough multicentric data collection, this study encompasses the largest series in the literature of clival chordomas surgically treated through an EETA. An increase in the use of this approach was found among Italian neurosurgical departments together with an improved extent of resection over time. The satisfactory rate of GTR was marked by low surgical morbidity and the preservation of patient quality of life. Surgical outcome was reinforced, in terms of PFS and OS, by the use of proton beam therapy, which was increasingly performed along the period of study.

BackgroundGlioblastoma stem cells (GSC) have been extensively recognized as a plausible cause of glioblastoma resistance to therapy and recurrence resulting in high glioblastoma mortality. Abnormalities in the DNA repair pathways might be responsible for the inability of the currently used chemotherapeutics to eliminate the (GSC) subpopulation.MethodsIn this work, we compared the expression of sixty DNA repair related genes between primary glioblastoma cell cultures and the glioblastoma enriched stem cell primary cultures. MTT test was used to analyze the effect of selected drugs and immunofluorescence to evaluate the load of DNA damage.ResultsWe found several differentially expressed genes and we identified topoisomerase IIβ (Top2β) as the gene with highest up-regulation in GSC. Also among the tested cell lines the expression of Top2β was the highest in NCH421k cells, a well-characterized glioblastoma cell line with all the stemness characteristics. On the other hand, Top2β expression markedly decreased upon the induction of differentiation by all trans-retinoic acid. Depletion of Top2β increased the sensitivity of NCH421k cells to replication stress inducing drugs, such as cisplatin, methyl-methanesulfonate, hydrogen peroxide, and temozolomide. Consistently, we found an increased load of DNA damage and increased Chk1 activation upon Top2β depletion in NCH421k cells.ConclusionWe suggest that Top2β may represent a new target for gene therapy in glioblastoma. In addition, the other genes that we found to be up-regulated in GSC versus glioblastoma primary cells should be further investigated as glioblastoma theranostics.Electronic supplementary materialThe online version of this article (doi:10.1186/s12935-016-0339-9) contains supplementary material, which is available to authorized users.