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As Neoplasias Mieloproliferativas (NMPs) se originam de alterações moleculares ao nível da célula-tronco hematopoética (CTHS), mas alterações do nicho da medula óssea podem também contribuir para a regulação das funções das células-tronco neoplásicas e normais residuais e assim, participar da fisiopatologia da doença. Apesar das NMPs serem bem descritas, a contribuição do microambiente na doença foi pouco estudada. Dessa forma, é nosso objetivo estudar como as células do microambiente contribuem para a doença. Acreditamos que as NMPs se originem não apenas de defeitos intrínsecos da CTHS, mas também da sua regulação por um nicho anormal, capaz de dar suporte proliferativo à mielopoese. Sendo assim, objetivamos caracterizar fenotipicamente as células que dão suporte ao nicho hematopoético localizado no endósteo (células endoteliais, osteoblastos e células-mesenquimais estromais) utilizando um modelo murino transgênico knockin de expressão heterozigótica condicional da mutação Jak2V617F. Para tanto, as células do nicho endosteal da medula óssea dos animais Jak2wt (controles) e Jak2VF (portadores de NMPs associada à mutação Jak2V617F) foram obtidas por meio de digestão dos fragmentos ósseos e caracterizadas por imunofenotipagem da MO total. Após exclusão de células hematopoéticas, as células do nicho foram identificadas como células endoteliais (CE, CD31+/Sca1+), células mesenquimais estromais (CM, CD31-/Sca-1+/CD51+) e Osteoblastos (OB, CD31-/Sca1-/CD51+). Os resultados deste trabalho possibilitaram estabelecer os métodos de isolamento de uma população pura de células mesenquimais no modelo transgênico Jak2V617F. Além disso, observamos diminuição dos osteoblastos nos animais Jak2VF em comparação aos controles Jak2wt. É possível que a deficiência numérica dos osteoblastos resulte em anormalidades funcionais no nicho que possam favorecer a expansão e/ou manutenção das células-tronco neoplásicas. Também não é possível excluir que as células-tronco neoplásicas exerçam um efeito supressor sobre o nicho, reduzindo subpopulações específicas do endósteo, sítio de importantes interações entre células-tronco e microambiente da medula óssea. Estas hipóteses geradas a partir de nossa caracterização fenotípica merecem esclarecimento por meio de estudos funcionais futuros. Myeloproliferative neoplasms (MPN) originate from molecular changes at the hematopoietic stem cells (HSC) level, but changes in the bone marrow niche may also contribute to the functional regulation of neoplastic and normal residual stem cells, and thus participate in the pathophysiology of the disease. Although MPN are well described, the contribution of the microenvironment to the disease has not been fully studied. Therefore, it is our goal to study how the cells from the bone marrow microenvironment contribute to the disease. We believe that MPN are initiated not only by intrinsic HSC defects but also by its regulation by an abnormal niche, that provides proliferative support to myelopoiesis. Therefore, we aimed to phenotypically characterize cells that support the hematopoietic niche located at the endosteum (endothelial cells, osteoblasts and mesenchymal stromal cells) by the use of a murine transgenic knockin model of conditional heterozygous expression of the Jak2V617F mutation. For that, cells from the bone marrow niche of Jak2wt (controls) and Jak2VF (animals with Jak2V617F-associated MPN) were obtained by bone digestion and characterized by immunophenotyping of the total bone marrow. After exclusion of hematopoietic cells, the niche cells were identified as endothelial cells (EC, CD31+/Sca1+), mesenchymal stromal cells (MSC, CD31-/Sca-1+/CD51+) and osteoblasts (OB, CD31-/Sca1-/CD51+). Our results showed that it was possible to establish the methods for isolation of a pure population of mesenchimal stromal cells in the Jak2V617F transgenic model. In addition, we observed a decreased frequency of osteoblasts in the Jak2VF animals when compared to Jak2wt controls. It is possible that the numeric deficiency of osteoblasts results in functional abnormalities of the niche that may favor the expansion or maintenance of the neoplastic stem cells. It is also plausible that neoplastic stem cells exert a suppressive effect on the niche cells, thus reducing specific subpopulations of the endosteum, a site of important interactions between stem cells and the microenvironment of the bone marrow. Such hypotheses generated by our study deserve to be further explored by future functional studies.

Papillary Thyroid Cancer (PTC) is an endocrine malignancy in which BRAFV600E oncogenic mutation induces the most aggressive phenotype. In this way, considering that lncRNAs are arising as key players in oncogenesis, it is of high interest the identification of BRAFV600E-associated long noncoding RNAs, which can provide possible candidates for secondary mechanisms of BRAF-induced malignancy in PTC. In this study, we identified differentially expressed lncRNAs correlated with BRAFV600E in PTC and, also, extended the cohort of paired normal and PTC samples to more accurately identify differentially expressed lncRNAs between these conditions. Indirectly validated targets of the differentially expressed lncRNAs in PTC compared to matched normal samples demonstrated an involvement in surface receptors responsible for signal transduction and cell adhesion, as well as, regulation of cell death, proliferation and apoptosis. Targets of BRAFV600E-correlated lncRNAs are mainly involved in calcium signaling pathway, ECM-receptor interaction and MAPK pathway. In summary, our study provides candidate lncRNAs that can be either used for future studies related to diagnosis/prognosis or as targets for PTC management.

Papillary Thyroid Cancer (PTC) is an endocrine malignancy in which BRAFV600E oncogenic mutation induces the most aggressive phenotype. In this way, considering that lncRNAs are arising as key players in oncogenesis, it is of high interest the identification of BRAFV600E-associated long noncoding RNAs, which can provide possible candidates for secondary mechanisms of BRAF-induced malignancy in PTC. In this study, we identified differentially expressed lncRNAs correlated with BRAFV600E in PTC and, also, extended the cohort of paired normal and PTC samples to more accurately identify differentially expressed lncRNAs between these conditions. Indirectly validated targets of the differentially expressed lncRNAs in PTC compared to matched normal samples demonstrated an involvement in surface receptors responsible for signal transduction and cell adhesion, as well as, regulation of cell death, proliferation and apoptosis. Targets of BRAFV600E-correlated lncRNAs are mainly involved in calcium signaling pathway, ECM-receptor interaction and MAPK pathway. In summary, our study provides candidate lncRNAs that can be either used for future studies related to diagnosis/prognosis or as targets for PTC management.