Epigenetic Mechanisms Histone Deacetylase-Dependent Regulate the Glioblastoma Angiogenic Matrisome and Disrupt Endothelial Cell Behavior In Vitro.

Glioblastoma (GBM) is the most aggressive brain tumor and different efforts have been employed in the search for new drugs and therapeutic protocols for GBM. Epitranscriptomics has shed light on new druggable Epigenetic therapies specifically designed to modulate GBM biology and behavior such as Histone Deacetylase inhibitors (iHDAC). Although the effects of iHDAC on GBM have been largely explored, there is a lack of information on the underlaying mechanisms HDAC-dependent that modulate the repertoire of GBM secreted molecules focusing on the set of Extracellular Matrix (ECM) associated proteins, the Matrisome, that may impact the surrounding tumor microenvironment. To acquire a better comprehension of the impacts of HDAC activity on the GBM Matrisome, we studied the alterations on the Matrisome-associated ECM regulators, Core Matrisome ECM glycoproteins, ECM-affiliated proteins and Proteoglycans upon HDAC inhibition in vitro as well as their relationship with glioma pathophysiological/clinical features and angiogenesis. For this, U87MG GBM cells were treated for with iHDAC or vehicle (control) and the whole secretome was processed by Mass Spectrometry NANOLC-MS/MS. In silico analyses revealed that proteins associated to the Angiogenic Matrisome (AngioMatrix), including Decorin, ADAM10, ADAM12 and ADAM15 were differentially regulated in iHDAC versus control secretome. Interestingly, genes coding for the Matrisome proteins differentially regulated were found mutated in patients and were correlated to glioma pathophysiological/clinical features. In vitro functional assays, using HBMEC endothelial cells exposed to the secretome of control or iHDAC treated GBM cells, coupled to 2D and 3D GBM cell culture system, showed impaired migratory capacity of endothelial cells and disrupted tubulogenesis in a Fibronectin and VEGF independent fashion. Collectively, our study provides understanding of epigenetic mechanisms HDAC-dependent to key Matrisomal proteins that may contribute to identify new druggable Epigenetic therapies or gliomagenesis biomarkers with relevant implications to improve therapeutic protocols for this malignancy.

Female naturalists and the patterns of suppression of women scientists in history: the example of Maria Sibylla Merian and her contributions about useful plants.

BACKGROUND: This work reunites many women naturalists who registered knowledge about native flora in scientific expeditions around the globe between the seventeenth and nineteenth centuries. Since male naturalists are more recognized in this period of time, we aimed to list female naturalists that published plant descriptions and observations, focusing on the work of Maria Sibylla Merian and to analyze her trajectory as an example to discuss the patterns of the suppression of women scientists. A second aim was to inventory the useful plants described in Maria Sibylla's Metamorphosis Insectorum Surinamensium and find pharmacological evidence about the traditional uses described for those plants cited as medicinal and toxic. METHODS: A survey of female naturalists was carried out by searching information in Pubmed, Scielo, Google Scholar and Virtual Health Library. Once Maria Sibylla published her book Metamorphosis Insectorum Surinamensium by her own, without male co-authors, and also this book is one of the only to have text and illustrations altogether and there are reports indicating information on useful plants in this work, she and her book were chosen as subject of this research. All the information was tabulated by dividing the plants into food, medicinal, toxic, aromatic or other uses. Finally, with the combinations of the scientific name of medicinal and toxic plants with information about their popular uses, a search was carried out in databases in order to indicate current pharmacological studies that reported evidences about the traditional uses described. RESULTS: We found 28 women naturalists who participated in scientific expeditions or trips, or in a curiosity cabinet, or who were collectors of Natural History between the seventeenth and nineteenth centuries. All these women illustrated botanical species and/or recorded their everyday or medicinal use or reported their observations in the form of a published work, letters or diaries. Also, the trajectory of Maria Sibylla Merian revealed that her scientific relevance has been neglected from the eighteenth century by mechanisms of suppression, most of the time by male depreciation, which can be seen as a pattern for suppression of women in science. However, Maria Sibyllas' contributions have been valued again in the twenty-first century. In Maria Sibylla's work, 54 plants were identified, 26 of them used for food, 4 of them aromatic, 8 medicinal, 4 toxic and 9 other uses. CONCLUSION: This study evidences that there are female naturalists whose work could be an important source for ethnopharmacological studies. Researching about women scientists, talking about them and highlighting the gender bias present in the scientific academy about the way the history of science is told is essential for the construction of a more diverse and richer scientific academy. The traditional use of 7 of 8 medicinal plants and 3 of 4 toxic plants reported was correlated with pharmacological studies, highlighting the importance of this historical record and its potential to direct strategic research in traditional medicine.

O-GlcNAcylation protein disruption by Thiamet G promotes changes on the GBM U87-MG cells secretome molecular signature.

Glioblastoma (GBM) is a grade IV glioma highly aggressive and refractory to the therapeutic approaches currently in use. O-GlcNAcylation plays a key role for tumor aggressiveness and progression in different types of cancer; however, experimental evidence of its involvement in GBM are still lacking. Here, we show that O-GlcNAcylation plays a critical role in maintaining the composition of the GBM secretome, whereas inhibition of OGA activity disrupts the intercellular signaling via microvesicles. Using a label-free quantitative proteomics methodology, we identified 51 proteins in the GBM secretome whose abundance was significantly altered by activity inhibition of O-GlcNAcase (iOGA). Among these proteins, we observed that proteins related to proteasome activity and to regulation of immune response in the tumor microenvironment were consistently downregulated in GBM cells upon iOGA. While the proteins IGFBP3, IL-6 and HSPA5 were downregulated in GBM iOGA cells, the protein SQSTM1/p62 was exclusively found in GBM cells under iOGA. These findings were in line with literature evidence on the role of p62/IL-6 signaling axis in suppressing tumor aggressiveness and our experimental evidence showing a decrease in radioresistance potential of these cells. Taken together, our findings provide evidence that OGA activity may regulate the p62 and IL-6 abundance in the GBM secretome. We propose that the assessment of tumor status from the main proteins present in its secretome may contribute to the advancement of diagnostic, prognostic and even therapeutic tools to approach this relevant malignancy.

Live Cell Imaging Supports a Key Role for Histone Deacetylase as a Molecular Target during Glioblastoma Malignancy Downgrade through Tumor Competence Modulation.

Glioblastoma (GBM) is the most aggressive tumor of the central nervous system, and the identification of the mechanisms underlying the biological basis of GBM aggressiveness is essential to develop new therapies. Due to the low prognosis of GBM treatment, different clinical studies are in course to test the use of histone deacetylase inhibitors (iHDACs) in anticancer cocktails. Here, we seek to investigate the impact of HDAC activity on GBM cell behavior and plasticity by live cell imaging. We pharmacologically knock down HDAC activity using two different inhibitors (TSA and SAHA) in two different tumor cell types: a commercial GBM cell line (U87-MG) and primary tumor (GBM011). Upon 72 hours of in vitro iHDAC treatment, GBM cells presented a very unusual elongated cell shape due to tunneling tube formation and independent on TGF-ß signaling epithelial to mesenchymal transition. Live cell imaging revealed that voltage-sensitive Ca++ signaling was disrupted upon HDAC activity blockade. This behavior was coupled to vimentin and connexin 43 gene expression downregulation, suggesting that HDAC activity blockade downgrades GBM aggressiveness mostly due to tumor cell competence and plasticity modulation in vitro. To test this hypothesis and access whether iHDACs would modulate tumor cell behavior and plasticity to properly respond to environmental cues in vivo, we xenografted GBM oncospheres in the chick developing the neural tube. Remarkably, upon 5 days in the developing neural tube, iHDAC-treated GBM cells ectopically expressed HNK-1, a tumor-suppressor marker tightly correlated to increased survivor of patients. These results describe, for the first time in the literature, the relevance of iHDACs for in vivo tumor cell morphology and competence to properly respond to environmental cues. Ultimately, our results highlight the relevance of chromatin remodeling for tumor cell plasticity and shed light on clinical perspectives aiming the epigenome as a relevant therapeutic target for GBM therapy.