Impacto do secretoma das células estaminais mesenquimatosas na patofisiologia dos glioblastomas

Os gliomas malignos são os tumores primários do cérebro mais frequentes, constituindo cerca de 80% de todas as neoplasias do sistema nervoso central, sendo o glioblastoma (GBM) o subtipo mais agressivo e letal. Mesmo com abordagens terapêuticas integradas, que incluem cirurgia, radioterapia e quimioterapia, o prognóstico de doentes com glioma continua a ser insatisfatório. As células estaminais mesenquimatosas (MSCs) têm sido estudadas como uma nova abordagem terapêutica para gliomas, uma vez que apresentam uma capacidade intrínseca de migrar para zonas de lesão, incluindo tumores, e podem ser modificadas para incorporarem agentes anti-tumorais. No entanto, ainda é questionável de que forma as MSCs, per se, influenciam a patofisiologia tumoral. Neste estudo, avaliámos o impacto do secretoma de MSCs em características de agressividade das células de GBM. Estudos in vitro demonstraram que células de GBM expostas a meios condicionados (MC) de células perivasculares humanas do cordão umbilical (HUCPVCs, uma população de MSCs) apresentavam aumentos na viabilidade, proliferação e migração celulares. Por outro lado, nenhum efeito foi observado na sensibilidade ao agente quimioterapêutico temozolamida. Ensaios in vivo demonstraram ainda que o MC das HUCPVCs promove a angiogénese e o crescimento tumoral. Finalmente, a caracterização do secretoma das HUCPVCs foi efetuada por análises de proteómica, o que permitiu identificar varias proteínas secretadas que estão envolvidas na sobrevivência, proliferação e migração das células de GBM, revelando novos potenciais mediadores moleculares envolvidos nos efeitos observados nas células de GBM. Em resumo, os nossos resultados sugerem que é necessária precaução no uso de MSCs como potenciais agentes terapêuticos para o tratamento de GBM.

Autores e Afiliações:

Joana Vieira de Castro,^1,2 Eduardo D. Gomes,^1,2 Sara Granja,^1,2 Sandra I. Anjo,^3,4 Fátima Baltazar,^1,2 Bruno Manadas,³ António J. Salgado,^1,2 and Bruno M. Costa^1,2

¹Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal;

²ICVS/3B’s-PT Government Associate Laboratory, University of Minho, Braga/Guimarães, Campus de Gualtar, 4710-057 Braga, Portugal;

³CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal;

⁴Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra, Portugal.

Abstract:

Background: Glioblastoma (GBM) is a highly aggressive primary brain cancer, for which curative therapies are not available. An emerging therapeutic approach suggested to have potential to target malignant gliomas has been based on the use of multipotent mesenchymal stem cells (MSCs), either unmodified or engineered to deliver anticancer therapeutic agents, as these cells present an intrinsic capacity to migrate towards malignant tumors. Nevertheless, it is still controversial whether this innate tropism of MSCs towards the tumor area is associated with cancer promotion or suppression. Considering that one of the major mechanisms by which MSCs interact with and modulate tumor cells is via secreted factors, we studied how the secretome of MSCs modulates critical hallmark features of GBM cells.

Methods: The effect of conditioned media (CM) from human umbilical cord perivascular cells (HUCPVCs, a MSC population present in the Wharton's jelly of the umbilical cord) on GBM cell viability, migration, proliferation and sensitivity to temozolomide treatment of U251 and SNB-19 GBM cells was evaluated. The in vivo chicken chorioallantoic membrane (CAM) assay was used to evaluate the effect of HUCPVCs CM on tumor growth and angiogenesis. The secretome of HUCPVCs was characterized by proteomic analyses.

Results: We found that both tested GBM cell lines exposed to HUCPVCs CM presented significantly higher cellular viability, proliferation and migration. In contrast, resistance of GBM cells to temozolomide chemotherapy was not significantly affected by HUCPVCs CM. In the in vivo CAM assay, CM from HUCPVCs promoted U251 and SNB-19 tumor cells growth. Proteomic analysis to characterize the secretome of HUCPVCs identified several proteins involved in promotion of cell survival, proliferation and migration, revealing novel putative molecular mediators for the effects observed in GBM cells exposed to HUCPVCs CM.

Conclusions: These findings provide novel insights to better understand the interplay between GBM cells and MSCs, raising awareness to potential safety issues regarding the use of MSCs as stem-cell based therapies for GBM.

Revista: Journal of Translational Medicine

Link: https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-017-1303-8