Abstract 3661: Extracellular vesicle derived from neural stem cells as potential vehicles of genetic information to modulate glioblastoma biology

Glioblastoma (GBM) is a deadly brain tumor and its high aggressiveness is partly due to a subpopulation of tumor stem cells known as glioblastoma stem-like cells (GSCs). GBM establishes crosstalk with non-tumoral cells, mediated mainly by extracellular vesicles (EVs) and the interaction between GSCs and neural stem cells (NSCs) from the subventricular zone may influence GBM biology. Literature data suggests that cellular communication is an important process for GSCs stemness maintenance, and some authors consider NSCs as a possible cell of origin for GSCs. However, the specific effects that neural stem cells-derived extracellular vesicles (NSCs-EVs) promote in GSCs are still uncertain. Previous data from our group demonstrated specific groups of microRNAs (hsa-miR -137, -216a-5p, -216b-5p, 217), enriched in NSCs-EVs in contrast to intracellular compartments, suggesting these molecules are being produced for secretion. Our study aims to evaluate the role of the miRs contained in NSCs-EVs in GSCs biology. Human induced pluripotent stem cells (hiPSC) were differentiated into NSCs. NSCs were characterized by western blotting and immunofluorescence by the expression of neural commitment markers, such as nestin and β-III-tubulin. NSCs-EVs were isolated from NSCs’ culture media with a commercial kit and analyzed by NTA (nanosight) for EVs size profiling and western blotting to detect specific markers, such as Alix, CD63, and HSP90. In a first approach, we analyzed the effects played by those miRs through predictive online tools. We identified target genes related to stemness (NANOG, SOX2, KLF4), oncogenesis (KRAS, CDC42, CDK6) and metabolism (CAMK2A), besides the Wnt and Notch signaling pathways. The online predictions also identified transcriptional factors related to vasculogenesis and self-renewal, key processes for GSCs activity. We will expose GSCs to NSCs-EVs and evaluate the expression of neural and stemness markers. In a future step, the GSCs previously exposed to NSCs-EVs will be treated with temozolomide, and viability assays will be performed. Additionally, we intend to modulate the four miRs identified and evaluate if they act as effector molecules of NSCs-EVs. Our data corroborate with our initial hypothesis that NSCs-EVs may act as important signalling modes in GSCs activity and consequently in GBM biology. Supported by FAPESP:22/08106-1.

Citation Format: João Pedro Alves de Araújo, Lilian Cruz, Maria Clara da Silva Souza, Mariana Brandão Prado, Rodrigo Nunes Alves, Bárbara Paranhos Coelho, Samuel Ribeiro Soares, Camila Félix Fernandes, Marilene Hohmuth Lopes. Extracellular vesicle derived from neural stem cells as potential vehicles of genetic information to modulate glioblastoma biology. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3661.

Unconventional Protein Secretion in Brain Tumors Biology: Enlightening the Mechanisms for Tumor Survival and Progression

Non-canonical secretion pathways, collectively known as unconventional protein secretion (UPS), are alternative secretory mechanisms usually associated with stress-inducing conditions. UPS allows proteins that lack a signal peptide to be secreted, avoiding the conventional endoplasmic reticulum-Golgi complex secretory pathway. Molecules that generally rely on the canonical pathway to be secreted may also use the Golgi bypass, one of the unconventional routes, to reach the extracellular space. UPS studies have been increasingly growing in the literature, including its implication in the biology of several diseases. Intercellular communication between brain tumor cells and the tumor microenvironment is orchestrated by various molecules, including canonical and non-canonical secreted proteins that modulate tumor growth, proliferation, and invasion. Adult brain tumors such as gliomas, which are aggressive and fatal cancers with a dismal prognosis, could exploit UPS mechanisms to communicate with their microenvironment. Herein, we provide functional insights into the UPS machinery in the context of tumor biology, with a particular focus on the secreted proteins by alternative routes as key regulators in the maintenance of brain tumors.

Multifaceted WNT Signaling at the Crossroads Between Epithelial-Mesenchymal Transition and Autophagy in Glioblastoma

Tumor cells can employ epithelial-mesenchymal transition (EMT) or autophagy in reaction to microenvironmental stress. Importantly, EMT and autophagy negatively regulate each other, are able to interconvert, and both have been shown to contribute to drug-resistance in glioblastoma (GBM). EMT has been considered one of the mechanisms that confer invasive properties to GBM cells. Autophagy, on the other hand, may show dual roles as either a GBM-promoter or GBM-suppressor, depending on microenvironmental cues. The Wingless (WNT) signaling pathway regulates a plethora of developmental and biological processes such as cellular proliferation, adhesion and motility. As such, GBM demonstrates deregulation of WNT signaling in favor of tumor initiation, proliferation and invasion. In EMT, WNT signaling promotes induction and stabilization of different EMT activators. WNT activity also represses autophagy, while nutrient deprivation induces β-catenin degradation via autophagic machinery. Due to the importance of the WNT pathway to GBM, and the role of WNT signaling in EMT and autophagy, in this review we highlight the effects of the WNT signaling in the regulation of both processes in GBM, and discuss how the crosstalk between EMT and autophagy may ultimately affect tumor biology.

Prion Protein at the Leading Edge: Its Role in Cell Motility

Cell motility is a central process involved in fundamental biological phenomena during embryonic development, wound healing, immune surveillance, and cancer spreading. Cell movement is complex and dynamic and requires the coordinated activity of cytoskeletal, membrane, adhesion and extracellular proteins. Cellular prion protein (PrPC) has been implicated in distinct aspects of cell motility, including axonal growth, transendothelial migration, epithelial-mesenchymal transition, formation of lamellipodia, and tumor migration and invasion. The preferential location of PrPC on cell membrane favors its function as a pivotal molecule in cell motile phenotype, being able to serve as a scaffold protein for extracellular matrix proteins, cell surface receptors, and cytoskeletal multiprotein complexes to modulate their activities in cellular movement. Evidence points to PrPC mediating interactions of multiple key elements of cell motility at the intra- and extracellular levels, such as integrins and matrix proteins, also regulating cell adhesion molecule stability and cell adhesion cytoskeleton dynamics. Understanding the molecular mechanisms that govern cell motility is critical for tissue homeostasis, since uncontrolled cell movement results in pathological conditions such as developmental diseases and tumor dissemination. In this review, we discuss the relevant contribution of PrPC in several aspects of cell motility, unveiling new insights into both PrPC function and mechanism in a multifaceted manner either in physiological or pathological contexts.

Duplication of Dio3 genes in teleost fish and their divergent expression in skin during flatfish metamorphosis

Deiodinase 3 (Dio3) plays an essential role during early development in vertebrates by controlling tissue thyroid hormone (TH) availability. The Atlantic halibut (Hippoglossus hippoglossus) possesses duplicate dio3 genes (dio3a and dio3b). Expression analysis indicates that dio3b levels change in abocular skin during metamorphosis and this suggests that this enzyme is associated with the divergent development of larval skin to the juvenile phenotype. In larvae exposed to MMI, a chemical that inhibits TH production, expression of dio3b in ocular skin is significantly up-regulated suggesting that THs normally modulate this genes expression during this developmental event. The molecular basis for divergent dio3a and dio3b expression and responsiveness to MMI treatment is explained by the multiple conserved TREs in the proximal promoter region of teleost dio3b and their absence from the promoter of dio3a. We propose that the divergent expression of dio3 in ocular and abocular skin during halibut metamorphosis contributes to the asymmetric pigment development in response to THs.

Orchestrating change: The thyroid hormones and GI-tract development in flatfish metamorphosis

Metamorphosis in flatfish (Pleuronectiformes) is a late post-embryonic developmental event that prepares the organism for the larval-to-juvenile transition. Thyroid hormones (THs) play a central role in flatfish metamorphosis and the basic elements that constitute the thyroid axis in vertebrates are all present at this stage. The advantage of using flatfish to study the larval-to-juvenile transition is the profound change in external morphology that accompanies metamorphosis making it easy to track progression to climax. This important lifecycle transition is underpinned by molecular, cellular, structural and functional modifications of organs and tissues that prepare larvae for a successful transition to the adult habitat and lifestyle. Understanding the role of THs in the maturation of organs and tissues with diverse functions during metamorphosis is a major challenge. The change in diet that accompanies the transition from a pelagic larvae to a benthic juvenile in flatfish is associated with structural and functional modifications in the gastrointestinal tract (GI-tract). The present review will focus on the maturation of the GI-tract during metamorphosis giving particular attention to organogenesis of the stomach a TH triggered event. Gene transcripts and biological processes that are associated with GI-tract maturation during Atlantic halibut metamorphosis are identified. Gene ontology analysis reveals core biological functions and putative TH-responsive genes that underpin TH-driven metamorphosis of the GI-tract in Atlantic halibut. Deciphering the specific role remains a challenge. Recent advances in characterizing the molecular, structural and functional modifications that accompany the appearance of a functional stomach in Atlantic halibut are considered and future research challenges identified.

Transcriptome of the Atlantic halibut (Hippoglossus hippoglossus)

Although the Atlantic halibut (Hippoglossus hippoglossus) is an important commercial species, there is still a deficit with regard to the number of transcripts in the databases, which can be accessed and exploited for targeted candidate gene and pathway studies. In this study, the RNAs from head, skin and GI tract from different developmental stages were sequenced to generate 22,272 contigs of 500 base pairs or greater as a molecular resource for this species.

The influence of urbanization on natural radiation levels in anomalous areas

This paper verifies the effects of urbanization on the original levels of environmental gamma radiation in an anomalous area. The fieldwork was done in the city of Guarapari, on the seacoast of the state of Espírito Santo, Brazil. This place was chosen because the whole region is naturally rich in monazite sand, which contains thorium and uranium. A similar study was also carried out in the 1960s. The measurements were done using an inorganic NaI scintillometer detector with Cu+Pb filters coupled to a scaler. The methodology of measurements used was similar to the one applied in the fieldwork carried out in the 1960s. In addition, a simulation was performed in the laboratory, to determine the attenuation of the materials used in the urbanization of the region. The results of this work clearly show that there was a reduction in the levels of external radiation in the streets and squares of Guarapari. It was concluded that the reduction was due to attenuation by the materials used in the urbanization.

[Reactions and feelings of the nursing professional towards death]

Through this paper which self explanatory and description we attempted to understand the reaction and feelings of nurses facing patients who are out of therapeutic possibility. W conducted individual, semi guided interviews with nine nurses from a general hospital in Maringá-PR about their reactions and feelings regarding forthcoming death on a daily base can be an extremely painful experience, therefore, they normally use self defense mechanics such as denial and reasoning death in order to live with daily losses. As a result these professional nurses may fail to notice the limits and their anxiety thus preventing them from providing a good quality of work in assisting their patients. Based on this fact we would like to suggest a prearranged space at the hospital where these health professionals could meet to share, reflect upon and express their anxieties, their fears, their helplessness and pain in face of death, enabling them to be better prepared for their daily losses.